Methods for improving treatment outcomes in patients undergoing ultrafiltration

Abstract

The invention relates to methods for improving treatment outcomes in patients undergoing ultrafiltration. Ultrafiltration during hemodialysis or fluid removal can induce sympathetic nervous system activation, hypovolemia, catecholamine surge, and widespread microvascular ischemia, leading to cardiac stunning, dialysis intolerance, and organ injury. Disclosed herein are methods of administering a therapeutically effective amount of one or more receptor agonists of the renin-angiotensin system (RAS), including angiotensin II, angiotensin III, angiotensin IV, angiotensin 1-7, and / or prorenin receptor (PRR) agonists, to maintain capillary perfusion and prevent ischemia. The methods reduce risk or incidence of catecholamine surge, intradialytic hypotension, cardiac dysfunction, and muscle cramps, and also prevent or minimize systemic ischemic injury to the brain, heart, kidneys, liver, and skeletal muscle. By preserving systemic microvascular blood flow, the disclosed methods mitigate or prevent dialysis-associated heart disease as well as neurocognitive impairment, including white matter injury, memory decline, and executive dysfunction. These approaches enable improved hemodynamic stability, achieving ultrafiltration targets without the need to adjust treatment goals, reducing the necessity for fluid bolus administration, aiding in reaching dry weight, achievement of dry weight goals, minimizing the occurrence and severity of skeletal muscle cramps, and reduced long-term cardiovascular and neurological complications in patients receiving ultrafiltration therapy.

Description

Attorney Docket No. 38215.0007P1METHODS FOR IMPROVING TREATMENT OUTCOMES IN PATIENTS UNDERGOING ULTRAFILTRATION CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims priority to US Provisional Application No.63 / 711,968, filed October 25, 2024, which application is hereby incorporated by reference in its entirety.SEQUENCE LISTING

[0002] The contents of the electronic sequence listing named '‘38215.0007Pl.xml,’’ created on October 22, 2025, and having a size of 21,570 bytes is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION

[0003] The invention relates to methods for improving treatment outcomes in patients undergoing ultrafiltration (UF) by administering a therapeutically effective amount of one or more agonists targeting receptors of the RAS, such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or an agonist targeting the prorenin receptor (PRR) to prevent a catecholamine surge and maintain blood flow in microvascular blood vessels.BACKGROUND OF THE INVENTION

[0004] Ultrafiltration is a process that involves the removal of excess fluid from a patient’s blood using a semipermeable membrane and pressure. It is a key component of hemodialysis, helping patients with kidney dysfunction achieve their target dry weight, as they cannot naturally expel excess fluid through their kidneys.

[0005] While necessary for treating renal failure and fluid overload, one of the significant challenges faced by patients undergoing maintenance ultrafiltration is the risk of ultrafiltration-induced microvascular ischemia and related adverse events due to a surge in catecholamines, primarily involving epinephrine and norepinephrine. During ultrafiltration, fluid is extracted quickly from the vascular compartment and the excess fluid in the interstitial tissue gradually refills the vascular space. However, it is common for the ultrafiltration rate to surpass the interstitial refill rate leading to hypovolemia. Although the hypovolemia is temporary, it triggers sympathetic nervous system activation resulting in thesecretion of catecholamines and vasoconstriction to maintain blood pressure, microvascular perfusion, and cardiac output. Hypovolemia can also contribute to a decline in blood pressure (e.g., hypotension) triggering release of catecholamines. Norepinephrine and epinephrine act to constrict blood vessels (vasoconstriction) to preserve blood pressure and redirect blood flow to vital organs. In addition, dialysis involves the removal of excess fluid and toxins, which can result in rapid changes in blood volume and electrolyte imbalances. These fluid and electrolyte shifts can stimulate the sympathetic nervous system and lead to the release of catecholamines. Further, the composition of the dialysis fluid can influence electrolyte balance and blood pH, further affecting the release of catecholamines. Finally, pain or discomfort during dialysis can also activate the sympathetic nervous system, resulting in a catecholamine surge.

[0006] The catecholamine surge not only increases heart rate and contractility (at first to maintain cardiac output), it can also result in vasoconstriction in peripheral and non-essential vascular beds. This can exacerbate blood flow issues, particularly in microvascular areas, where smaller vessels are more vulnerable to constriction ultimately leading to a decrease in regional wall motion and cardiac stunning. Excessive release of catecholamines can lead to peripheral vasoconstriction, affecting microvascular perfusion, especially in tissues that require constant blood flow. The catecholamine surge can result in intense vasoconstriction of small arterioles and capillaries, particularly in peripheral tissues. As these smaller vessels constrict, microvascular perfusion can be compromised, leading to ischemia - a condition where tissues are deprived of oxygen and nutrients due to inadequate blood flow.

[0007] The clinical implications are many. Dialysis-induced hypotension and the subsequent catecholamine surge can create a vicious cycle. As the body tries to compensate for low blood volume and pressure, microvascular ischemia can result, leading to tissue damage or dysfunction. The heart is particularly vulnerable to such effects, as cardiac stunning (reversible cardiac dysfunction) and microvascular ischemia can lead to long-term cardiovascular complications if not addressed. The catecholamine surge during ultrafiltration in dialysis, driven by sympathetic nervous system activation, can lead to widespread vasoconstriction and capillary de-recruitment, resulting in microvascular ischemia, impaired skeletal muscle oxygenation and organ dysfunction or injury contributing to in critical organs, particularly in the heart (see Diinser MW, et al., “Sympathetic overstimulation during critical illness: adverse effects of adrenergic stress,’' J Intensive Care Med 24:293-316, 2009; Burton et al.. “Hemodialysis-induced cardiac injury: determinants and associated outcomes”, Clin. J. Am. Soc. Nephrol. 2009, May; 4(5):914-20; Burton et al. “Hemodialysis-inducedrepetitive myocardial injury results in global and segmental reduction in systolic cardiac function’7, Clin. J. Am. Soc. Nephrol. 2009, Dec. 4(12): 1925-31). Microvascular ischemia may not present as classic chest pain, but it can lead to myocardial stunning or subtle cardiac injury. This is especially significant in patients with pre-existing heart conditions, where compromised coronary microcirculation can worsen outcomes.

[0008] Cardiac stunning during hemodialysis occurs when reduced blood flow causes temporary dysfunction of the heart muscle, leading to microvascular ischemia in the myocardium. This condition is exacerbated by intradialytic hypotension (IDH), which results from significant shifts in fluid balance and blood pressure during the procedure. The repetitive ischemic episodes caused by drastic hemodynamic changes during hemodialysis can reduce blood flow to the heart muscle, particularly in patients with pre-existing cardiovascular conditions, resulting in left ventricular regional wall motion abnormalities and long-term cardiac damage. However, cardiac stunning is not limited to patients with coronary artery disease, as it also occurs in children, underscoring the broader cardiac toxicity of conventional hemodialysis treatments (see Hothi, et al., “Pediatric myocardial stunning underscores the cardiac toxicity of conventional hemodialysis treatments”, Clin. J. Am. Soc. Nephrol. 2009 Apr; 4(4): 790-7). The existence of microvascular ischemia and cardiac stunning is not dependent upon the existence of hypotension; it exists in patients with normal blood pressure. Ultrafiltration alone can activate the sympathetic nervous system and cause arginine vasopressin to increase arterial resistance.

[0009] Other organs can be affected. In addition to cardiac stunning, ultrafiltration can also cause organ ischemia, such as in the brain and kidneys, which can also be highly sensitive to changes in microvascular flow.

[0010] The brain can suffer from ischemia during hemodialysis due to impaired blood flow, similar to the effects seen in acute ischemic strokes. McIntyre’s studies using diffusion tensor MRI scans and neurocognitive testing have demonstrated progressive deficits in attention, memory, and executive function in patients undergoing chronic ultrafiltration. See Eldehni et al., “Exploring hemodynamics of hemodialysis using extrema points analysis model,” Theor. Biol. Med. Model. 2013, 10:33; Eldehni et al., “Brain white matter microstructure in endstage kidney disease, cognitive impairment, and circulatory stress,” Hemodial Int. (2019) 23:356-65. This contributes to cognitive symptoms such as dizziness, confusion or fatigue, memory loss, and other neurological issues frequently observed in HD patients. Cognitive impairment is one of the most significant long-term complications of dialysis, with microvascular ischemia and white matter injury implicated as underlying mechanisms.

[0011] Similarly, the kidneys — already compromised in dialysis patients — can be further affected by the recurrent ischemia resulting in acute kidney injury’. Cumulatively, the dysfunction to a multiplicity of organ systems leads to dialysis fatigue, all of which are related to the same cause: microvascular ischemia.

[0012] Furthermore, the catecholamine surge can contribute to fatigue and muscle cramps, which are common in dialysis patients, due to compromised blood flow to the skeletal muscles.

[0013] Thus, in addition to cardiac injury, ultrafiltration-induced catecholamine surges and microvascular ischemia can impair systemic organ perfusion, an effect that extends beyond the myocardium to include the brain, kidneys, and skeletal muscles. Recurrent episodes of microvascular ischemia during ultrafiltration contribute to cumulative end-organ dysfunction, manifested as fatigue, cognitive decline, muscle cramping, and dialysis intolerance.

[0014] The effects of catecholamine surge are made worse by the fact that patients requiring ultrafiltration can have reduced renin-angiotensin (RAS) response and / or reduced plasma concentrations of angiotensin II. It has been shown that angiotensin II (All) can maintain capillary patency by increasing postcapillary resistance more than precapillary resistance. Szczepanska-Sadowska E. “Hemodynamic effects of a moderate increase of the plasma vasopressin level in conscious dogs.” Pflugers Arch Eur J Physiol 1973;338:313-22. 27; Jarhult J. “Comparative effects of angiotensin and noradrenaline on resistance, capacitance, and precapillary sphincters in cat skeletal muscle.”Acto Physiol Scand 1971;81:315-24. For these patients, the RAS system is less able to modulate the impact of the catecholamine surge.

[0015] It has been demonstrated that administering prazosin, a drug that blocks the a-adrenergic receptors thus preventing vasoconstriction via catecholamines, is effective to reduce intradialytic cramp frequency. Sidhom OA, Odeh YK, Krumlovsky FA, Budris WA, Wang Z, Pospisil PA, et al. Low-dose prazosin in patients with muscle cramps during hemodialysis. Clin. Pharmacol. Ther. 1994;56:445-451. But this also prevents the body from being able to increase blood pressure leading to hypotension. As such, blocking the a-adrenergic receptors is not a viable treatment method.

[0016] It has also been shown that surgical activation of arginine vasopressin (AVP) release, which preferentially constricts precapillary arterioles, causes concentration-related decline in the capillary hydrostatic pressure and increasing the fraction of closed capillaries (derecruitment). See Sedek GS, et al. “Splanchnic tissues are a major part of the rapiddistribution spaces of inulin, urea, and theophylline.” J Pharmacol Exp Ther 1989;251:1026-31; Atkinson AJ Jr, et al., "‘Physiological basis of multicompartmental models of drug distribution.” Trends Pharmacol Sci 1991;12:96-101. Progressive dysfunction of the RAS system in dialysis patients with decreased production of angiotensin II exaggerates this imbalance, resulting in capillary dropout and ischemia.

[0017] As mentioned above, ultrafiltration leads to the production and secretion of catecholamines such as epinephrine and norepinephrine, which cause vasoconstriction via the a-adrenergic receptor. Although both epinephrine and norepinephrine activate the |3-adrenergic receptor, which increases heart rate and cardiac contractility, excess β-adrenergic activation causes direct cardiac injury. See Brooks, W. W. and Conrad, C. H., “Isoproterenol-induced myocardial injury and diastolic dysfunction in mice: structural and functional correlates”, Comp. Med. 2009, Aug, 59(4): 339-343. When catecholamine levels increase or surge, they can cause acute cardiac dysfunction and injury known as Takotsubo syndrome or cardiomyopathy. See Campana et al., “Catecholamine-induced Takotsubo syndrome: a case series,” Eur. Heart J. Case Rep., 2023, Jul, 7(7) 1-6.

[0018] Therefore, there is a need for ultrafiltration methods that can effectively remove excess water from the patient while maintaining blood pressure, preventing a decline in blood pressure (e g., hypotension), preventing a catecholamine surge, and minimizing or preventing microvascular ischemia, without which can lead to long term damage of the heart and other organs, as well as other undesirable ultrafiltration side effects, all of which can hinder the patient from achieving their dry weight and increase the likelihood of discontinuing treatment.SUMMARY OF INVENTION

[0019] The present invention is in some aspects directed to the administration of angiotensin II (All) receptor agonists to maintain blood pressure and prevent a catecholamine surge in patients undergoing ultrafiltration to improve ultrafiltration treatment outcomes and to prevent or minimize adverse effects associated with ultrafiltration.

[0020] The present invention is in some aspects directed to the administration of agonists targeting receptors of the RAS to maintain blood pressure and prevent a catecholamine surge, which could cause vasoconstriction and microvascular ischemia.

[0021] The present invention is in other aspects directed to the administration of agonists that target the Mas receptor to maintain perfusion in microvascular tissue structures, alone or incombination with agonists that target a RAS receptor to maintain blood pressure and prevent a catecholamine surge, to patients undergoing ultrafiltration to improve ultrafiltration treatment outcomes and to prevent or minimize adverse effects associated with ultrafiltration.

[0022] The present invention is in other aspects directed to the administration of agonists that target the prorenin receptor (PRR), to enhance angiotensin II production that will help maintain blood pressure, alone or in combination with agonists that target the Mas receptor to maintain perfusion in microvascular tissue structures, alone or in combination with agonists that target a RAS receptor to maintain blood pressure and prevent a catecholamine surge, to patients undergoing ultrafiltration to improve ultrafiltration treatment outcomes and to prevent or minimize adverse effects associated with ultrafiltration.

[0023] Since the RAS is comprised of 2 axes with opposing functions: the pressor axis, represented by AT1R (angiotensin type 1 receptor), which mediates the vasoconstrictive effects of the RAS, and the depressor axis, which exerts vasodilatory effects through AT2R (angiotensin type 2 receptor) or its specific Mas receptor, the present invention is in some aspects directed to the administration of agonists targeting receptors of the RAS, to maintain blood pressure to prevent a catecholamine surge, and to promote vasodilation to maintain perfusion in microvascular tissue structures.

[0024] The present invention is in some aspects directed to the administration of agonists targeting receptors of the RAS, such as angiotensin III, to promote vasodilation and prevent microvascular ischemia.

[0025] The present invention is in some aspects directed to the administration of agonists targeting receptors of the RAS, such as angiotensin IV (AIV), to promote vasodilation and prevent microvascular ischemia.

[0026] The present invention is in some aspects directed to the administration of agonists targeting receptors of the RAS, such as angiotensin 1-7, to promote vasodilation and prevent microvascular ischemia.

[0027] The present invention is in other aspects directed to the administration of agonists of the ATR1 receptor, alone or in combination with ATR2 receptor agonists, alone or in combination with AT4 receptor agonists, alone or in combination with Mas receptor agonists to patients undergoing ultrafiltration to improve ultrafiltration treatment outcomes and to prevent or minimize adverse effects associated with ultrafiltration.

[0028] The present invention is in other aspects directed to the administration of PRR agonists, alone or in combination with RAS receptor agonists, to patients undergoingultrafiltration to improve ultrafiltration treatment outcomes and to prevent or minimize adverse effects associated with ultrafiltration.

[0029] In still other aspects, the method of the invention provides for the maintenance or increase in the cardiac output and / or cardiac index, prevention of cardiac injury, prevention of cardiac stunning, prevention of an increase in biomarkers of cardiac injury, e.g., troponin I, creatine kinase-mb, and for a reduction in the incidence of cardiac dysfunction (e.g., regional wall motion abnormalities that lead to cardiac remodeling) and / or cardiac muscle injury of the subject during ultrafiltration. Thus, disclosed are methods of maintaining cardiac output, maintaining the cardiac index, preventing an increase in troponin I or creatine kinase-mb biomarkers in patients undergoing hemodialysis with administering receptor agonists of the RAS. such as angiotensin II. angiotensin III, angiotensin IV, angiotensin 1-7. and / or PRR agonist. Also disclosed are methods of minimizing and / or preventing cardiac dysfunction and / or cardiac muscle injury during ultrafiltration by administering receptor agonist of the RAS, such as angiotensin II, angiotensin III, angiotensin IV, angiotensin 1-7, and / or PRR agonists.

[0030] In other aspects, the method of the invention enables a subject undergoing ultrafiltration to avoid a decline in blood pressure (e.g., incidence of hypotension). Thus, disclosed are methods of preventing a decline in blood pressure in a subject undergoing ultrafiltration by administering one or more RAS receptor agonists, such as angiotensin II, angiotensin III. angiotensin IV, angiotensin 1-7. and / or a PRR agonist.

[0031] In another aspect, the method of the invention enables a subject undergoing ultrafiltration to avoid intradialytic hypotension that leads to cardiac stunning and cardiac remodeling as a result of ultrafiltration. Thus, disclosed are methods of preventing intradialytic hypotension that leads to cardiac stunning and cardiac remodeling in a patient undergoing ultrafiltration by administering one or more RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV, angiotensin 1-7, and / or a PRR agonist.

[0032] In yet other aspects, the method of the invention enables a subject undergoing ultrafiltration to achieve their dry weight goal. Thus, disclosed are methods of enabling a subject undergoing ultrafiltration to achieve their dry weight goal by administering one or more RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or a PRR agonist such as prorenin and renin.

[0033] In still other aspects, the method of the invention provides for a reduction in the need for bolus fluid administration to the subject, a reduction in the need to reduce the ultrafiltration goal of the subject, and / or a reduction in the need to discontinue or terminateultrafiltration for the subject. Thus, disclosed are methods of minimizing the need for bolus fluid administration to the subject, minimizing the need to reduce the ultrafiltration goal of the subject, and / or minimizing or preventing the need to discontinue or terminate ultrafiltration by administering one or more RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or a PRR agonist such as prorenin and renin.

[0034] In yet another aspect, the method of the invention enables a subject undergoing ultrafiltration to prevent systemic microvascular ischemia and its consequences across multiple organ systems including the brain, heart, kidney and other organ systems that are sensitive to temporary ischemia, as a result of ultrafiltration. Thus, disclosed are methods of preventing ischemia in the brain, heart, kidney, or other organs in a patient undergoing dialysis by administering one or more RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or a PRR agonist such as prorenin and renin.

[0035] In other aspects, the methods of the invention reduce the risk of cerebral microvascular ischemia and thereby prevent or mitigate neurocognitive impairment, including memory low, executive dysfunction and dialysis-related vascular dementia.Cognitive impairment is a particularly significant long-term complication of dialysis. By administering a therapeutically effective amount of one or more RAS receptor agonists and / or PRR agonists to preserve capillary perfusion during ultrafiltration, the inventive methods reduce the risk of cerebral ischemia and thereby prevent or mitigate neurocognitive impairment. Thus, disclosed are methods of preventing neurocognitive impairment in a patient undergoing dialysis by administering one or more RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or a PRR agonist such as prorenin and renin. In certain embodiments, neurocognitive outcomes may be assessed by serial neuropsychological testing, including but not limited to, Montreal Cognitive Assessment (MoCA), Trail Making Test, or Wechsler Memory Scale, in patients undergoing ultrafiltration with or without administration of a RAS receptor agonist.Preservation or improvement of test scores over time compared to baseline is an additional measure of treatment efficacy. Imaging biomarkers, such as diffusion tensor MRI or functional MRI, may also be used to demonstrate preserved white matter integrity and reduced ischemic injury.

[0036] In some aspects, the present invention is directed to a method of minimizing or preventing muscle cramps in a subject undergoing ultrafiltration, the method comprisingadministering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or a PRR agonist such as prorenin and renin. In other aspects, the administration of the RAS agonists and / or PRR agonists during dialysis results in a reduction in the incidence of cramping during ultrafiltration as well as a reduction in the incidence of severe cramps during ultrafiltration. In some aspects, the subject experiences two or less cramps per ultrafiltration session. In other aspects, the subject experiences one or less severe cramps per ultrafiltration session. In still other aspects, the subject experiences one or less cramps in the upper extremities. And in yet other aspects, the subject experiences an increase in systolic blood pressure and / or heart rate, or the subject does not experience ultrafiltration-induced hypotension. In other aspects, the method of the invention provides for a delay in the onset of dialytic cramps during ultrafiltration, wherein the subject does not experience a cramp until at least 50%, at least 60%, at least 70%, at least 80% or at least 90%, of the ultrafiltration treatment session has been completed. Thus, also disclosed are methods of delaying the onset of skeletal muscle cramps in patients undergoing ultrafiltration by administering RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or PRR agonists such as prorenin and renin.

[0037] According to the inventive methods described herein, the agonists are administered to patients undergoing ultrafiltration before, during, or after ultrafiltration treatment. In some aspects, the subject undergoing ultrafiltration has chronic or end-stage kidney disease.

[0038] According to the inventive methods described herein, the therapeutically effective amount of RAS receptor agonists and / or PRR agonists is administered to the subject at a rate between about 0.1 ng / kg / min and about 20 ng / kg / min of body weight of the subject.

[0039] In some aspects, the therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist is administered to the subject by continuous infusion, e.g., at a low dose of angiotensin II. In some aspects, the continuous infusions can include pauses in the infusion, e.g., for a period in time to allow the subjects blood pressure to decrease. The infusion can occur in the extracorporeal circuit, including the extracorporeal circuit pre-filter and extracorporeal circuit post-filter.

[0040] In other aspects, the therapeutically effective amount of one or more RAS receptor agonist such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or PRR agonists such as prorenin and renin can be administered to the subject in accordance with any of the methods described herein at an initial infusion rate of 1 ng / kg / min. After 15 minutes, the infusion rate can be increased in increments to 0.5 to 2 ng / kg / min every 15minutes until either a maximum infusion rate of 30 ng / kg / min is reached or the systolic blood pressure reaches 180 mmHg. In some aspects, a therapeutically effective amount of angiotensin II is administered to the subject at a concentration of 5 pg / mL in 0.9% sodium chloride solution. The therapeutically effective amount of angiotensin II is administered at a median infusion rate of angiotensin II administered to the subject is 2.5 ng / kg / min and, in some aspects, the infusion rate of angiotensin II does not exceed 10 ng / kg / min.DESCRIPTION OF THE DRAWING

[0041] FIG. 1 shows a CRAMP-HD study flow chart.

[0042] FIG. 2 shows a time-series boxplot with overlaid jittered points representing pain scores at various time intervals after the commencement of dialysis according to treatment assignment.This time-series Boxplot with Jittered Points Overlay and Statistical Annotation shows the distribution of pain scores measured using the Brief Pain Inventory (BPI) at different times after the start of dialysis for two different treatments, Angiotensin II and Placebo. The jittered points represent individual pain score measurements to display the data spread and outliers, while the boxplot summarizes the central tendency and variability. Except four instances, all occurrences of a pain score greater than zero were seen in the placebo group. The statistical annotation provides the effect size and p-value for the Angiotensin II treatment effect.

[0043] FIGS. 3A-3C shows an example of percentage of participants experiencing cramps at each site during the intervention. (A) overall, (B) angiotensin II, (C) placebo

[0044] FIGS. 4A-4D show hemodynamic changes during intervention according to treatment assignment. (A) systolic blood pressure vs time after the start of dialysis. (B) Diastolic blood pressure vs time after the start of dialysis. (C) Mean arterial pressure vs time after the start of dialysis. (D) Heart rate vs time after the start of dialysis.

[0045] FIG. 5 shows a time-series boxplot with overlaid jittered points representing dosage used at various time intervals after the commencement of dialysis according to treatment assignment.

[0046] FIG. 6 shows a cardiac index during intervention according to treatment assignment.

[0047] FIG. 7 shows a cardiac output during intervention according to treatment assignment.

[0048] FIG. 8 shows a comparison of troponin I pre and post intervention according to treatment assignment.

[0049] FIG. 9 shows a comparison of creatine kinase pre and post intervention according to treatment assignment.

[0050] FIG. 10 shows a comparison of renin pre and post intervention according to treatment assignment.DETAILED DESCRIPTION OF THE INVENTION

[0051] The present invention features methods of improving treatment outcomes of patients undergoing ultrafiltration comprising the administration of one or more RAS receptor agonists, such as angiotensin II and / or a Mas receptor agonist, and / or a PRR agonist.A. Definitions

[0052] It is understood that the disclosed method and compositions are not limited to the particular methodology, protocols, and reagents described as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims.

[0053] It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to “a dose” includes a plurality of such doses, reference to “the dose” is a reference to one or more doses and equivalents thereof known to those skilled in the art, and so forth.

[0054] As used herein, the term “subject” or “patient” refers to any organism to which a composition of this invention may be administered, e.g., for experimental, diagnostic, and / or therapeutic purposes. Typical subjects include animals (e.g., mammals such as non-human primates, and humans; avians; domestic household or farm animals such as cats, dogs, sheep, goats, cattle, horses, and pigs; laboratory animals such as mice, rats, and guinea pigs; rabbits; fish; reptiles; zoo and wild animals). Typically, “subjects” are animals, including mammals such as humans and primates, and the like.

[0055] As used herein, the term “treating” refers to partially or completely alleviating, ameliorating, relieving, mitigating, preventing, delaying onset of, inhibiting, or slowing progression of, reducing severity of, and / or reducing incidence of cardiac injury. Treatment can be administered to a subject who does not exhibit signs of cardiac injury and / or to a subject who exhibits signs of cardiac injury.

[0056] As used herein, “preventing’' is meant to mean minimize the chance that a subject who has an increased susceptibility for developing a disease, disorder or condition will develop the disease, disorder, or condition (e.g., cardiac injury, catecholamine-associated cardiac injury). For example, prevent as used herein can mean minimize the chance that a subject who is at risk of cardiac injury will develop it.

[0057] As used herein, the terms “administering” and “administration” refer to any method of providing a disclosed composition (e.g., angiotensin II) to a subject. Such methods are well known to those skilled in the art and include, but are not limited to: oral administration, transdermal administration, administration by inhalation, nasal administration, topical administration, intravaginal administration, ophthalmic administration, auricular administration, intracerebral administration, rectal administration, sublingual administration, buccal administration, and parenteral administration, including injectable such as intravenous administration, intra-arterial administration, intramuscular administration, and subcutaneous administration. Administration can be continuous or intermittent. In various aspects, a preparation can be administered therapeutically: that is, administered to treat an existing disease or condition. In further various aspects, a preparation can be administered prophylactically; that is, administered for prevention of a disease or condition.

[0058] The term “RAS receptor agonist” refers to agonists that mediate the pressor or depressor actions like angiotensin II and its metabolites. Key receptors in the RAS are the angiotensin type 1 receptor (ATR1). the angiotensin type 2 receptor (ATR2). the angiotensin ty pe 4 receptor (ATR4) and the Mas receptor. The peptide hormone angiotensin II is an example of an angiotensin II type 1 or 2 receptor agonist with its pressor activity7acting on ATR1. The peptide hormone angiotensin 1-7 is an example of Mas receptor agonist. The peptide hormone angiotensin III is an example of an angiotensin II type 1 or type 2 receptor agonist. The peptide hormone angiotensin IV is an example an angiotensin type 4 receptor agonist.

[0059] The term “PRR agonist” refers to agonists or the prorenin receptor including prorenin and renin.

[0060] The term “angiotensin II” may refer to Asp-Arg-Val-Tyr-Ile-His-Pro-Phe [SEQ ID NO: 1] also called 5-isoleucine angiotensin II. SEQ ID NO: 1 is an octa-peptide naturally present in humans and other species, such as equines, hogs, etc. Isoleucine may be substituted by valine to result in 5-valine angiotensin II, Asp-Arg-Val-Tyr-Val-His-Pro-Phe [SEQ ID NO: 2], Other angiotensin II analogues such as [Asnl - Phe4 ]-angiotensin II [SEQ ID NO: 3], hexapeptide Val-Tyr-Ile-His-Pro-Phe [SEQ ID NO: 4], nonapeptide Asn-Arg-Val-Tyr-Tyr-Val-His-Pro-Phe [SEQ ID NO: 5], [Asn'-Ileu5 -Ileu8 ]-angiotensin II [SEQ ID NO: 6], [Asnl -Ileu5 -Ala8 ]-angiotensin II [SEQ ID NO: 7], and [Asnl -diiodoTyr4 -Ileu5]-angiotensin II [SEQ ID NO: 8] may also be used. Angiotensin II may be synthesized, for example, by solid phase peptide synthesis to incorporate modifications, such as C-terminal amidation. C-terminal acetate groups may also be added. Fragments of angiotensin II which retain the activity of angiotensin II may also be used, for example angiotensin II fragments wherein an N terminal amino acid is deleted, or angiotensin II fragments in which a C terminal is deleted (e.g., Ang III, Ang IV and Ang 11(1-7)). The term ‘‘angiotensin II,” without further specificity, is intended to refer to any of these various forms, as well as combinations thereof.

[0061] The term “cardiac dysfunction” refers to any disturbance or abnormality in the function of the heart including left ventricular systolic dysfunction (e.g., reduced (<40%) left ventricular echocardiographic ejection fraction (LVEF) or impaired global longitudinal strain (GLS)), left ventricular diastolic dysfunction defined on the basis of left ventricular filling pattern as any abnormal relaxation (mitral E / A <0.5, deceleration time >280 milliseconds), pseudonormal filling (e.g., left atrial size at or above the sex-specific 80th percentile, left ventricular mass at or above the sex-specific 80th percentile, or any atrial fibrillation) or restrictive filling (mitral E / A >2.0, deceleration time <120 milliseconds)), right atrial enlargement, or right ventricular dysfunction, or regional wall motion abnormalities, which are defined as regional abnormalities in contractile function.

[0062] The term “cardiac stunning” refers to a state of cardiac dysfunction that can occur in a portion of the cardiac muscle after a brief interruption in blood flow despite restoration of normal blood flow to that portion. The cardiac dysfunction can remain for a variable period of time ranging from hours to days or even weeks. Stunning may also be causes by excess beta-adrenergic stimulation as seen in Takotsubo syndrome.

[0063] The term “ultrafiltration” (UF) refers to a process in which water and small solutes are filtered through a semipermeable membrane w hile larger molecules, such as proteins and cells, are retained. Ultrafiltration is commonly used in medical treatments to remove excess fluids from the body or to separate substances based on their size and / or manage fluid overload. In conditions such as heart failure or kidney failure, ultrafiltration is used to remove excess fluids that the body cannot eliminate naturally. In critical care and renal support, ultrafiltration is vital in providing continuous filtration for patients unable to undergo conventional dialysis due to instability.

[0064] The term “hemodialysis’' refers to a procedure that filters waste products, excess salts, and water from the blood, commonly used for patients with kidney failure. It involves a machine with a semipermeable membrane called a dialyzer (artificial kidney). Blood from the patient flows on one side of the membrane, while a dialysis solution (dialysate) flows on the other. Ultrafiltration in this process helps remove excess fluids, which can accumulate in patients with kidney dysfunction. Continuous Renal Replacement Therapy (CRRT) is a slow, continuous form of hemodialysis used in critically ill patients who cannot tolerate rapid fluid removal. It removes fluid and solutes gradually through UF over 24 hours.

[0065] The term “plasmapheresis” refers to a blood purification process where plasma, the liquid part of the blood, is separated from cells. The process is used to treat autoimmune diseases, certain neurological disorders, and remove harmful antibodies or proteins from the blood.

[0066] The term “hemofiltration” refers to a blood purification process similar to hemodialysis but primarily focusing on removing water and solutes from the blood through UF. It is often used for patients in acute kidney failure or critical care. Unlike hemodialysis, which relies on diffusion, hemofiltration uses convection to remove solutes with the fluid.

[0067] The term “peritoneal dialysis” refers to dialysis wherein the peritoneal membrane inside the abdomen acts as a filter. A dialysis solution is introduced into the abdominal cavity, and waste products diffuse into this solution from the blood vessels in the peritoneal membrane.

[0068] The term “pharmaceutically acceptable salt,” as used herein, represents those salts which are, within the scope of sound medical judgment, suitable for use. Thephy sicochemical and biological properties of drug substances are greatly affected by their salt forms. The choice of a particular salt formulation is based on numerous factors such as the drug substance chemistry, intended dosage form, pharmacokinetics, and pharmacodynamics. The selection of a counterion is based on the degree of ionization of the acidic or basic functional groups that are present in the drug. Consideration is made with respect to the drug substance contact with the tissues of humans and animals without undue toxicity, irritation, allergic response and the like and are commensurate with a reasonable benefit / risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, pharmaceutically acceptable salts are described in: Berge et al., J. Pharmaceutical Sciences 66: 1-19, 1977, and in Pharmaceutical Salts: Properties, Selection, and Use, (Eds. P. H. Stahl and C. G.Wermuth), Wiley-VCH, 2008. The salts can be prepared in situ during the final isolation and purification of the compounds described herein or separately by reacting the free base groupwith a suitable organic acid. Representative acid addition salts include acetate, adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptonate, glycerophosphate, hemisulfate, heptonate, hexanoate, hydrobromide, hydrochloride, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, toluenesulfonate, undecanoate, valerate salts, and the like.Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like, as well as nontoxic ammonium, quaternary ammonium, and amine cations, including, but not limited to ammonium, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, triethylamine, ethylamine, and the like.

[0069] An “effective amount’" of a drug or composition is that amount of drug or composition which is sufficient to provide a beneficial effect to the subject to which the drug or composition is administered. The phrase “therapeutically effective amount”, as used herein, refers to an amount that is sufficient or effective to prevent or treat (delay or prevent the onset of, prevent the progression of, inhibit, decrease or reverse) a disease or condition, including alleviating symptoms of such diseases.

[0070] “Low dose” or “low dosage” means a dose that prevents a decline in blood pressure, but avoids a clinically adverse, prolonged rise in blood pressure.

[0071] “Optional” or “optionally” means that the subsequently described event, circumstance, or material may or may not occur or be present, and that the description includes instances where the event, circumstance, or material occurs or is present and instances where it does not occur or is not present.

[0072] Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, also specifically contemplated, and considered disclosed, is the range from the one particular value and / or to the other particular value unless the context specifically indicates otherwise. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another, specifically contemplated embodiment that should be considered disclosed unless the context specifically indicates otherwise. It will be further understood that the endpoints of each of the ranges are significant both in relationto the other endpoint, and independently of the other endpoint unless the context specifically indicates otherwise. Finally, it should be understood that all of the individual values and subranges of values contained within an explicitly disclosed range are also specifically contemplated and should be considered disclosed unless the context specifically indicates otherwise. The foregoing applies regardless of whether in particular cases some or all of these embodiments are explicitly disclosed.

[0073] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of skill in the art to which the disclosed method and compositions belong. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present method and compositions, the particularly useful methods, devices, and materials are as described.Publications cited herein and the material for which they are cited are hereby specifically incorporated by reference. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such disclosure by virtue of prior invention. No admission is made that any reference constitutes prior art. The discussion of references states what their authors assert, and applicants reserve the right to challenge the accuracy and pertinence of the cited documents. It will be clearly understood that, although a number of publications are referred to herein, such reference does not constitute an admission that any of these documents forms part of the common general knowledge in the art.

[0074] Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers, or steps. In particular, in methods stated as comprising one or more steps or operations it is specifically contemplated that each step comprises what is listed (unless that step includes a limiting term such as “consisting of”), meaning that each step is not intended to exclude, for example, other additives, components, integers or steps that are not listed in the step.

[0075] As further described herein, the invention is in some aspects directed to methods of administering agonists of the RAS and / or PRR to patients undergoing ultrafiltration in order to prevent a decline in circulating blood volume and thereby prevent the catecholamine surge so as to prevent the incidence of microvascular ischemia and resulting adverse effects.

[0076] The invention is further directed to methods for maintaining cardiovascular and sympathetic nervous system homeostasis in a patient undergoing ultrafiltration, comprising administering to the patient a therapeutically effective amount of a RAS receptor agonist suchas angiotensin II and / or PRR agonist, wherein the administration modulates blood pressure and blood flow, thereby reducing the activation of the sympathetic nervous system and minimizing a catecholamine surge. In some aspects such methods will further prevent or reduce vasoconstriction in the microvasculature, thereby minimizing the risk of microvascular ischemia during or following ultrafiltration, reducing the need for administration to the patient of other pharmacological agents, such as vasopressors or fluid boluses, that are commonly used to mitigate intradialytic hypotension and its associated catecholamine response, minimizing the risk of cardiac dysfunction, including cardiac stunning, by reducing the catecholamine-induced vasoconstriction and maintaining consistent myocardial perfusion during ultrafiltration, modulating vascular tone by acting on angiotensin II receptors to promote vasodilation in non-essential vascular beds, reducing systemic vascular resistance and the body’s need to release epinephrine and norepinephrine, helping maintain fluid-electrolyte balance during ultrafiltration, contributing to homeostatic stability and minimizing the activation of stress-related pathways, including the catecholamine response, and / or preventing the excessive release of catecholamines, which can lead to peripheral vasoconstriction, thereby reducing the frequency and severity of skeletal muscle cramps during ultrafiltration.

[0077] The invention is also directed to a method for improving the clinical outcome of ultrafiltration by administering a therapeutically effective amount of a RAS receptor agonist such as angiotensin II and / or PRR agonist, to a patient, wherein the administration ensures stable cardiac output, prevents fatigue, and minimizes brain and kidney injury by reducing the incidence of catecholamine surge and its effects on microvascular ischemia.B. RAS Receptor Agonists and PRR Agonists

[0078] The renin-angiotensin system (RAS) is comprised of 2 axes with opposing functions. The pressor axis, represented by AT1R (Ang [angiotensin] II type 1 receptor), which mediates the vasoconstrictive, trophic, and proinflammatory effects of the RAS, and the depressor axis, which exerts vasodilatory, anti-inflammatory, and antifibrotic effects through Ang (1-7) and its specific Mas (Mas receptor).

[0079] The methods of the invention involve administration of RAS receptor agonists to a subject. In some aspects, the RAS receptor agonists can be drugs (e.g., synthetic compounds or natural substances) or compositions that stimulate the ATI receptor, which can cause vasoconstriction, aldosterone secretion, cardiac and / or tissue remodeling, sympathetic nervous system activation, and stimulate proinflammatory’ and profibrotic pathways. The ATI receptor is found in many tissues including the heart, kidneys, vasculature, brain, andadrenal glands. In other aspects, the RAS receptor agonists can be drugs (e.g., synthetic compounds or natural substances) or compositions that stimulate the AT2 receptor, which can cause vasodilation, have anti-inflammatory and antifibrotic effects, stimulate neuroprotection and tissue repair. The AT2 receptor is found mainly in fetal tissues, but in adults, it is present in the heart, kidney and brain. Information on the angiotensin II receptor mechanisms is described in de Gasparo M et al. Int 'I Union Pharmacol. XXIII. “The angiotensin II receptors. Pharmacological Reviews"’, 2000; 52(3):415-472 and Foulquier et al., Nature, " A tale of two receptors”, 2014; 493: S9, each of which are incorporated by reference herein.

[0080] In still other aspects, the RAS receptor agonists can be drugs (e.g., synthetic compounds or natural substances) such as angiotensin 1-7 or compositions that stimulate the Mas receptor. Mas receptor agonists can be administered to modulate the action of and / or mitigate detrimental effects of ultrafiltration. The Mas receptor is a key component of the renin-angiotensin system (RAS), specifically involved in vasodilation, anti-inflammatory, and cardioprotective effects. The Mas receptor is found in the heart, blood vessels, kidneys, brain, and lungs. Information on the mechanisms by which the Mas receptor mediates vasodilation and opposes the effects of the ATI receptor is described in Santos, R. A., Sampaio, W. O., Alzamora, A C., ‘'The ACE2 / angiotensin-(l-7) / Mas axis of the renin-angiotensin system: Focus on angiotensin-(l-7)." Physiological Reviews (2018) and Ferrario, C. M., et al. "Counterregulatory Actions of Angiotensin-(l-7)." Hypertension (2013), each of which are incorporated by reference herein.

[0081] In still other aspects, drugs or compositions that target different RAS receptors (e.g., the AT4 receptor) or the prorenin receptor (PRR) can be administered to modulate the action of and / or mitigate detrimental effects of other RAS agonists. In some aspects, drugs (e.g., synthetic compounds or natural substances) or compositions that stimulate the AT4 receptor, such as AIV can be administered, which drugs can affect cognitive function, cause vasodilation, and can have neurological effects. The AT4 receptor is found in the brain, heart, kidneys, and endothelium. Information on the AT4 receptor mechanism is described in Wright JW, Harding JW. “The brain renin-angiotensin system: A diversity of functions and implications for CNS diseases. ” Pflugers Arch. - Eur. J. Physiol. 2013; 465(1): 133-151 and Gard PR. “Cognitive-enhancing effects of angiotensin IV.” BMC Neurosci. 2008; 9(Suppl 2), each of which are incorporated by reference herein.

[0082] In yet other embodiments, drugs (e.g., synthetic compounds or natural substances) or compositions that stimulate the pro-renin receptor (PRR) can be administered, which drugs can cause RAS activation, cellular proliferation, inflammation, and oxidative stress. The(pro)renin receptor is a multifunctional protein that is expressed in multiple organs including the kidney, heart, vascular smooth, brain, adipose tissue, liver, eye and placenta. Binding to the PRR activates angiotensin-II dependent and independent pathways. Information on the PRR mechanism is described in Nguyen G, Muller DN. “The biology of the (pro)renin receptor.'’ J. Am. Soc. Nephrol. 2010; 21(l):18-23 and Batenburg WW et al., “Prorenin is the endogenous agonist of the (pro)renin receptor: Binding kinetics and effects on smooth muscle cells.” J. Hypertens. 2007; Dec.25(12):2441-2453, each of which are incorporated by reference herein.

[0083] In some aspects of the invention, the RAS receptor agonist can be angiotensin II. Angiotensin II is a peptide hormone naturally produced by the body. Angiotensin II regulates blood pressure via vasoconstriction and sodium reabsorption. Hemodynamic effects of angiotensin II administration have been the subject of numerous clinical studies, demonstrating significant effects on systemic and renal blood flow (Harrison-Bernard, L. M., The renal renin-angiotensin system. Adv Physiol Educ., (2009) 33(4): p. 270-74). Angiotensin II is a hormone produced by the renin-angiotensin-aldosterone system (RAAS) that modulates blood pressure via regulation of vascular smooth muscle tone and extracellular fluid homeostasis. Angiotensin II mediates its effects on the vasculature by inducing vasoconstriction and sodium retention. In addition to its systemic effects, angiotensin II has a pronounced effect on the efferent arterioles of the kidney, maintaining glomerular filtration when blood flow is decreased. Angiotensin II also regulates sodium reabsorption in the kidney by stimulating Na+ / H+ exchangers in the proximal tubule and inducing the release of aldosterone and vasopressin (Harrison-Bernard, L. M., The renal renin-angiotensin system. Adv. Physiol. Educ., 2009. 33(4): p. 270-4).

[0084] The sequence of angiotensin II used in the compositions and methods disclosed herein may be homologous to the sequences of angiotensin II described above. In certain aspects, the invention includes isolated, synthetic, or recombinant amino acid sequences that are at least 80%, 85%, 90%, 95%, 97%, 98%, 99% or 100% identical to SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, and / or 8. Any such variant sequences may be used in place of an angiotensin II as described in the preceding paragraph.

[0085] In some aspects, the angiotensin II may be selected from 5-valine angiotensin II, 5-valine angiotensin II amide, 5-L -isoleucine angiotensin II, and 5-L-isoleucine angiotensin II amide, or a pharmaceutically acceptable salt thereof, preferably manufactured under current good manufacturing conditions (cGMP). In some aspects, the composition may include different forms of angiotensin II in different percentages, e.g., a mixture of hexapeptide andnonapeptide angiotensin. The composition comprising angiotensin II may be suitable for parenteral administration, e.g.. for injection or intravenous infusion.

[0086] Similarly, an angiotensin II therapeutic may be used as any suitable salt, deprotected form, acetylated form, deacetylated form, and / or prodrug form of the above-mentioned peptides, including pegylated forms of the peptides or conjugates as disclosed in U. S. Pat. No. 7,666,408 (incorporated by reference). The term "prodrug" refers to any precursor compound which is able to generate or to release the above-mentioned peptide under physiological conditions. Such prodrugs may be larger peptides which are selectively cleaved in order to form the peptide of the invention. For example, in some aspects, the prodrug may be angiotensin I or its homologues that may result in angiotensin II by the action of certain endogenous or exogenous enzymes. Further prodrugs include peptides with protected amino acids, e.g., having protecting groups at one or more carboxylic acid and / or amino groups. Suitable protecting groups for amino groups are the benzyloxy carbonyl, t-butyloxycarbonyl (BOC), fluorenylmethyloxycarbonyl (FMOC), formyl, and acetyl or acyl group. Suitable protecting groups for the carboxylic acid group are esters such as benzyl esters or t-butyl esters. The present invention also contemplates the use of angiotensin II and / or precursor peptides having amino acid substitutions, deletions, additions, the substitutions and additions including the standard D and L amino acids and modified amino acids, such as, for example, amidated and acetylated amino acids, wherein the therapeutic activity of the base peptide sequence is maintained at a pharmacologically useful level.

[0087] In some aspects the angiotensin II is synthetic human angiotensin II having a chemical name of L-Asparty 1-L-arginyl-L-valyl-L-tyrosyl-L-isoleucyl-L-histidyl-L-prolyl-L-phenylalanine, acetate salt. Molecular formula: C₅₀H₇₁N₁₃O₁₂ • (C₂H₄O₂)n; (n= number of acetate molecules; theoretical n = 3), Average molecular weight: 1046.2 (as free base).

[0088] In another embodiment, the invention features prodrug forms of RAS receptor agonists (e.g., angiotensin II) for use in the treatment methods described herein. One example of an angiotensin II pro-drug is the peptide angiotensin I, which has the sequence Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu (SEQ ID NO:1). Another example of an angiotensin II prodrug is the protein angiotensinogen, which is a 452-amino acid protein, which is cleaved by a protease, renin, to produce angiotensin I.

[0089] The invention also features the use of non-peptide agonists of angiotensin II in the methods described herein. Methods for designing and synthesizing non-peptidic chemical structures are well known in the art of medicinal chemistry.

[0090] Angiotensin II (All) is an octapeptide having a molecular weight of 1046.2 Daltons and the following structure:H-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-OH (SEQ ID NO:2)

[0091] All is the classical effector of the renin-angiotensin cascade and is formed endogenously from angiotensinogen by two successive hydrolytic reactions. Several All polypeptide metabolites of All also act on angiotensin receptors, and it is likely that small molecule agonists can also be developed and employed. All is available commercially for clinical research as a sterile dry powder supplied in glass vials. It is intended to be administered intravenously after reconstitution in physiological saline.

[0092] Although All has been administered to human subjects both by injection and infusion, it is the prior experience with infusions that is most relevant to the current use of this agent. All infusions generally have been used to probe physiological responses in normal subjects and in patients, but in a few instances have been administered as therapy to treat patients with septic shock that has become refractory to catecholamines, during cesarean section to maintain blood pressure during spinal anesthesia, and to deliver intra-arterial chemotherapy more selectively.

[0093] In other aspects, the methods of the invention involve administration of a RAS receptor agonist, including the Mas receptor, and / or agonists of the prorenin receptor (PRR), including but are not limited to, the angiotensin II compounds described above, [125I] [Sar 1 ] angiotensin II (e.g., [125I]Sar-Arg-Val-Tyr-Ile-His-Pro-Phe)(SEQ ID NO. 11), [125I][Sar', He8] -angiotensin II (e.g., Sar-Arg-Val-Tyr-Ile-His-Pro-Ile-OEI) (SEQ ID NO. 12), [Sar1, Cha8] angiotensin-II (e.g., Sar-Arg-Val-Tyr-Val-His-Pro-Cha-COOH) (SEQ ID NO. 13), [Sar1, Cha4] angiotensin -II (e.g., Sar-COOH)(SEQ ID NO. 14), 1-sarcosine, 8-isoleucine angiotensin II ([Sar1, He8] angiotensin II) (e.g., Sar-Arg-Val-Tyr-Ile-His-Pro-Ile-OH) (SEQ ID NO. 15), 1-sarcosine, 8-alanine angiotensin II ([Sar1, Ala8] -angiotensin II), [p-aminoPhe6] angiotensin II (e.g., Asp-Arg-Val-Tyr-He-(p-amino-Phe)-Pro-Phe) (SEQ ID NO. 16), angiotensin III (e.g., Arg-Val-Tyr-He-His-Pro-Phe) (SEQ ID NO: 17), angiotensin A (e.g., Ala-Arg-Val-Tyr-Ile-His-Pro-Phe) (SEQ ID NO. 18), CGP42112 (i.e., (2S,3S)-2-[[(2S)-l-[(2S)-2-[[(2S)-6-[[(2S)-5-(diaminomethylideneamino)-2- (phenylmethoxycarbonylamino)pentanoyl]amino]-2-[[(2S)-3-(4-hydroxyphenyl)-2-(pyridine-3-carbonylamino)propanoyl]amino]hexanoyl]amino]-3-(3H-imidazol-4-yl)propanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoic acid), angiotensin IV (e.g., Val-Tyr-Ile-His-Pro-Phe) (SEQ ID NO: 19), angiotensin-(l-7) or [125I] angiotensin-(l-7) (e.g.,Asp-Arg-Val-Tyr-Ile-His-Pro (SEQ ID NO:20) or (2S)-l-[(2S)-2-[[(2S,3S)-2-[[(2S)-2-[[(2S)-2- [[(2S)-2- [ [(2S)-2-amino-4-hy droxy-4-oxobutanoyl] amino] -5 -(diaminomethylideneamino)pentanoyl]amino]-3-methylbutanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-3-methylpentanoyl]amino]-3-(3H-imidazol-4-yl)propanoyl]pyrrolidine-2-carboxylic acid), AVE-0991 (i.e., 3-ethyl-l-[3-[4-[(5-formyl-4-methoxy-2-phenylimidazol- 1 -yl)methyl] phenyl] -5-(2-methylpropyl)thiophen-2-yl] sulfonylurea), novokinin (e.g., Arg-Pro-Leu-Lys-Pro-Trp) (SEQ ID NO:21), Compound 21 (i.e., 3-[4-(lH-imidazol-l-ylmethyl)phenyl]-5-(2-methylpropyl)thiophene-2-[(N-butyloxylcarbamate)-sulphonamide] sodium salt; see also Wan Y, Wallinder C, Plouffe B et al. Design, synthesis, and biological evaluation of the first selective nonpeptide AT2 receptor agonist. J Med. Chem. 2004;47:5995-6008, which is incorporated by reference herein), Compound 38 (i.e., 3-[(4-morpholin-4-ylbenzoyl)amino]-N-[(lS)-l-phenyl-2-pyrrolidin-l-ylethyl]-lH-thieno[5,4-d]pyrazole-5-carboxamide), L-163,101 (i.e., N-[2-[4-[(2-ethyl-5,7-dimethylimidazo[4,5-b]pyridin-3-yl)methyl]phenyl]-4-(2-methylpropyl)phenyl]sulfonylbenzamide), L-162,313 (i.e., butyl N-[3-[4-[(2-ethyl-5.7-dimethylimidazo[5,4-b]pyridin-3-yl)methyl]phenyl]-5-(2-methylpropyl)thiophen-2-yl] sulfonylcarbamate), TRV023 (e.g., H-Sar-Arg-Val-Tyr-Lys-His-Pro-Ala-OH) (SEQ ID NO:22), TRV026 (e.g., H-Sar-Arg-Val-Tyr-Lys-His-Pro-NH2) (SEQ ID NO:23), LVV-hemorphin (e.g., Leu-Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe) (SEQ ID NO:24), AR234958 (i.e., 1 -(4-fluorophenyl)-4- { [4-(3 -fluorophenyl)- 1 -(2-methoxy-4-nitrobenzenesulfonyl)pyrrolidin-3-yl]methyl}piperazine), AR234960 (i.e., l-[[4-(3-fluorophenyl)-I-(2-methoxy-4-nitrophenyl)sulfonylpyrrolidin-3-yl]methyl]-4-pyri din-2-ylpiperazine), prorenin and renin.

[0094] Angiotensin III is a metabolite of angiotensin II. formed by the removal of a single amino acid from the latter. It retains significant biological activity and serves multiple important functions in the RAS. Like angiotensin II, angiotensin III stimulates the release of aldosterone from the adrenal glands, leading to increased sodium retention and potassium excretion in the kidneys. This process plays a key role in maintaining blood pressure and electrolyte balance. Although less potent than angiotensin II in terms of vasoconstriction, angiotensin III still contributes to blood pressure regulation. It exerts effects primarily through angiotensin type 1 (ATI) receptors, leading to mild vasoconstriction and aiding in maintaining systemic vascular resistance. Angiotensin III plays a role in the central nervous system (CNS) by stimulating thirst and sodium appetite, thereby contributing to fluid balance. It also influences the sympathetic nervous system to help regulate blood pressure via centralmechanisms. Angiotensin III has been shown to activate AT2 receptors, which are known to oppose the effects of ATI receptors. Activation of AT2 receptors leads to vasodilation, antiinflammatory effects, and tissue repair, counterbalancing the vasoconstrictive and pro-inflammatory actions of ATI receptor activation.

[0095] In still other embodiments of the invention, the method involves administering angiotensin II in combination with an agent that has vasodilation effects such angiotensin III, angiotensin IV, angiotensin 1-7, C21 and / or CGP42H2A.C. Modes of administration

[0096] Administration of RAS receptor agonists and / or PRR agonists can be by any convenient route, e.g., intravenous (using either a bolus or by a steady infusion), intramuscular, intra-osseos, subcutaneous or inhalation.

[0097] The compositions of the invention containing RAS receptor agonists and / or PRR agonists can be administered in a variety of conventional w ays. In some aspects, the compositions of the invention are suitable for parenteral administration. These compositions may be administered, for example, intraperitoneally, intravenously, intra-arterially, intra-renally, or intrathecally. In some aspects, the compositions of the invention are injected intravenously. One of skill in the art would appreciate that a method of administering a therapeutically effective substance formulation or composition of the invention w ould depend on factors such as the age, weight, and physical condition of the patient being treated, and the disease or condition being treated. The skilled worker w ould. thus, be able to select a method of administration optimal for a patient on a case-by-case basis.

[0098] In general, RAS receptor agonists and / or PRR agonists may be administered to a patient orally, by subcutaneous, intramuscular, intravenous or other modes of injection, or in any other manner. Depending on the specific application, the RAS receptor agonists and / or PRR agonists will generally be administered as infusions (e.g., continuous infusion) to patients beginning at the start of hemodialysis and continuing through this procedure.

[0099] In one embodiment of the invention, one or more RAS receptor agonists and / or a PRR agonist is administered to a patient before or during ultrafiltration, using the same intravenous line that is established for the ultrafiltration itself. In a preferred version of this embodiment, the RAS receptor agonist(s) and / or RPR agonists is added into the distal injection port of the hemodialysis machine in the line that returns blood from the dialysis cartridge to the patient.D. Doses of the Therapeutically Effective Substance

[0100] The dose of RAS receptor agonist and / or PRR agonist that is used depends on the particular agonist that is employed. For example, when angiotensin II itself is used, thestarting dose can be about 1-30, about 1-20, about 1-10, or about 1-5 ng / kg / min by continuous infusion. Similar doses can be used for other RAS receptor agonists and / or PRR agonists. For example, for angiotensin I the same dose may be used. For angiotensin III or IV, half the dose may be used.

[0101] A preferred dose of RAS receptor agonist and / or PRR agonist is between about 0.1 and about 30 ng / kg of body weight per minute of administration (ng / kg / min). More preferably a dose between 0.5 and 20 ng / kg / min is used. Even more preferably a dose between 1 and 10 ng / kg / min is used. Desirably, a low dose of the RAS agonist and / or PRR agonist is used, meaning that the dose administered is lower than the dose of such agent when used as vasopressor. When angiotensin II is used, the dose of angiotensin II is less than 20 ng / kg / min, for example a dose that is about 10 ng / kg / min or lower (e.g., between about 0.5 and 10 ng / kg / min), or about 7.5 ng / kg / min or lower (e.g., between about 0.5 and 7.5 ng / kg / min), or about 6 ng / kg / min or lower (e.g., between about 0.5 and 6 ng / kg / min), or about 4 ng / kg / min or lower (e.g., between about 0.5 and 4 ng / kg / min).

[0102] In some aspects, the dose administration of a RAS receptor agonist and / or a PRR agonist is commenced within 15 minutes (before or after) of the beginning of the ultrafiltration treatment and will continue during the entire duration of ultrafiltration treatment. In other aspects, the administration can be commenced prior to the ultrafiltration treatment, for example, the angiotensin II administration can be commenced 30 minutes, 45 minutes, 60 minutes. 90 minutes, 120 minutes, 150 minutes, 180 minutes before the ultrafiltration treatment. Similarly, the administration can be continued after the ultrafiltration treatment, for example, the administration can be continued for 30 minutes, or 45 minutes or 60 minutes after the ultrafiltration treatment symptoms.

[0103] In some aspects, the dose administration is commenced at a time that corresponds to the onset of cramping in a previous ultrafiltration session. Thus, in some aspects, the dosing can be individualized for each subject. In some aspects, the dose administration is commenced within 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes of a time that corresponds to the onset of cramping in the subj ect in a previous ultrafiltration session.

[0104] The RAS receptor agonist and / or PRR agonist infusion rate is increased or decreased to meet the requirements of individual patients. Desirably the infusion rate is adjusted so as to maintain a systolic blood pressure between about 100 and 180 mmHg. According to another embodiment of the invention, an initial dose of 1 ng / kg- min is used and is increased over time (e.g., by 0.5 to 2 ng / kg / min every' 15 minutes) until the systolic bloodpressure reaches 180 mmHg or a final dose of about 15 ng / kg / min or lower (e.g., between about 0.5 and 15 ng / kg / min), or about 10 ng / kg / min or lower (e.g., between about 0.5 and 10 ng / kg / min), or about 7.5 ng / kg / min or lower (e.g., between about 0.5 and 7.5 ng / kg / min), or about 6 ng / kg / min or lower (e.g., between about 0.5 and 6 ng / kg / min), or about 4 ng / kg / min or lower (e.g., between about 0.5 and 4 ng / kg / min).. The dose may be decreased (e.g., if systolic blood pressure rises more than 10 mmHg) or increased (e.g., if systolic pressure falls more than 10 mmHg) during administration of the RAS receptor agonist and / or PRR agonist. A particularly effective dose is between about 1.5 ng / kg / min to about 5 ng / kg / min or a median dose of about 2.5 ng / kg / min.E. Subject Population

[0105] The method of the invention involves administering RAS receptor agonists, e.g.. All, AIII, AIV, and / or angiotensin 1-7 and / or PRR agonists to a human subject undergoing or having reason to undergo ultrafiltration, such as hemodialysis, treatment for fluid overload, or peritoneal dialysis. In some aspects, the subject may require continuous renal replacement therapy (CRRT), for example the subject may have chronic kidney disease (CKD) (e.g., any of stages 1-5). In other aspects, the subject may have acute kidney injury (AKI). Common causes of kidney failure include diabetes, high blood pressure (hypertension), kidney inflammation (glomerulonephritis), kidney cysts (polycystic kidney disease), inherited kidney disease, and long-term use of nonsteroidal anti-inflammatory drugs or other medications that could harm the kidneys. The subject may also have acute kidney failure resulting from a severe illness, complicated surgery, coronary ischemia, cerebrovascular accident or other serious problem. The subject may also have fluid overload that requires ultrafiltration.

[0106] The subject may have additional conditions related to the ultrafiltration treatment. Such additional conditions include reduced blood pressure (hypotension), muscle cramps, itching, sleep problems, anemia, bone disease, high blood pressure (hypertension), hyperkalemia, hypokalemia, pericarditis, amyloidosis, or other complications associated with hemodialysis treatment.

[0107] In some aspects, subjects that have higher (above average) muscle mass are more likely to get cramping during ultrafiltration. Thus, in some aspects, treating subjects undergoing ultrafiltration that have high muscle mass with angiotensin II can prevent cramping from occurring.F. Methods Related to the Administration of RAS Receptor Agonists and / or PRR agonists

[0108] One aspect of the invention is a method of treatment comprising administering a therapeutically effective dose of a RAS receptor agonist, e.g., All, and / or PRR agonist to a subject undergoing ultrafiltration. The administration of a RAS receptor agonist and / or a PRR agonist to a subject undergoing ultrafiltration can lead to improvement in outcomes of ultrafiltration treatment and to the reduction or prevention of negative outcomes associated with ultrafiltration treatment.a. Methods Related to Improving Cardiac Outcomes

[0109] In other aspects of the invention, the method, in addition to providing each of the below described benefits, produces an increase in systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and / or heart rate (HR) in the subject undergoing ultrafiltration. In some aspects, this occurs without any significant adverse impact on cardiac output (CO) or cardiac index (CI) or on biomarkers of cardiac or muscle injury such as troponin (e.g., troponin I) and creatine kinase-mb. In yet other aspects of the invention, RAS receptor agonist, e.g.. All, and / or PRR agonist administration can reduce and / or prevent cardiac injury, reduce and / or prevent decrease in cardiac output, and / or reduce and / or prevent cardiac stunning. These are significant advantages of the method. As such, the method of the invention provides for maintenance or increase in the cardiac output and / or cardiac index, prevention of cardiac injury, prevention of cardiac stunning, prevention of an increase in biomarkers of myocardial injury such as troponin I and / or prevention of an increase in creatine kinase-mb and / or renin, and for reduction in the incidence of cardiac dysfunction (e.g., long term cardiac dysfunction such as congestive heart failure) and / or cardiac muscle injury’ of the subject during ultrafiltration. Thus, disclosed are methods of maintaining cardiac output, maintaining the cardiac index, preventing a rise in troponin and / or creatine kinase-mb and / or renin levels in patients undergoing hemodialysis with administering a RAS receptor agonist such as angiotensin II and / or a Mas receptor agonist and / or PRR agonists. Also disclosed are methods of minimizing and / or preventing cardiac dysfunction and / or cardiac muscle injury during ultrafiltration by administering a RAS receptor agonist such as angiotensin II and / or PRR agonists.

[0110] Subjects undergoing ultrafiltration treatment frequency experience intradialytic hypotension during ultrafiltration and subjects undergoing chronic ultrafiltration frequently develop cardiovascular complications including atrial fibrillation, stroke, and heart failure.

[0111] Cardiac stunning during ultrafiltration refers to a transient reduction in heart function, often occurring due to a series of physiologic events initiated during the treatment. Hemodialysis involves the removal of excess fluid from the blood to prevent fluid overload. However, when fluid is removed too quickly, it can cause a sudden reduction in blood volume (hypovolemia) which in turn can diminish the amount of blood returning to the heart (venous return or preload). This results in less blood available for the heart to pump out during each contraction. With reduced preload, the heart’s stroke volume (the amount of blood pumped with each heartbeat) declines, which leads to a drop in cardiac output (the total volume of blood the heart pumps per minute). This can trigger compensatory mechanisms, such as increased heart rate, but may not fully restore normal circulation. The reduction in blood volume and cardiac output often leads to lowering of blood pressure (hypotension), a common side effect of hemodialysis. Hypotension reduces the perfusion pressure necessary to maintain adequate blood flow to vital organs, particularly the heart. With lower systemic blood pressure and decreased perfusion, blood flow to the coronary arteries (which supply oxygen-rich blood to the heart muscle) is compromised. The lack of adequate oxygen delivery (ischemia) to the myocardium (heart muscle) results in myocardial stunning — a reduction in the contractile function of the heart as evidenced by a decline in regional wall motion. Even after blood flow is restored, the affected myocardial tissue may remain dysfunctional for hours to days. Repeated episodes of ischemia and cardiac stunning over time, especially if ultrafiltration sessions are frequent and fluid removal is aggressive, can lead to chronic, cumulative cardiac damage. This may contribute to the development of heart failure, left ventricular hypertrophy, or other long-term cardiovascular complications.

[0112] In some aspects, RAS receptor agonist, e.g., All, and / or a PRR agonist administration can cause venous constriction which pushes blood from the extremities to the heart thus helping prevent loss of blood pressure (e.g., interdialytic hypotension) and other cardiac related issues or injuries.b. Methods Related to Preventing Ischemia

[0113] In other aspects, RAS receptor agonist, e.g., AIL and / or PRR agonist administration can help to maintain blood flow in the capillary bed which will thereby help to prevent critical organ ischemia (e.g., microvascular ischemia), such as in the heart, brain (cerebral or cerebrovascular ischemia), and kidneys.

[0114] In other aspects, RAS receptor agonist, e.g., AIL and / or PRR agonist administration can help to prevent injury to organs such as the heart (e.g., ischemic heart disease, myocardial infarction, abnormal heart rhythms), brain (e.g., cerebral infarction orischemic stroke), gut (e.g., bowel ischemia, intestinal ischemia / reperfusion, mesenteric ischemia), liver (e.g., ischemic hepatitis) and / or kidneys (e.g., renal ischemia / reperfusion injury (IRI)).

[0115] As such, the method of the invention provides for minimization or prevention of ischemia (e.g., microvascular ischemia) of the subject during ultrafiltration. Thus, disclosed are methods of preventing critical organ ischemia (e.g., microvascular ischemia), such as in the heart, brain, and kidneys, in patients undergoing hemodialysis with administering a RAS receptor agonist such as angiotensin II and / or a PRR agonist.

[0116] In still other aspects, the administration of the RAS receptor agonist, e.g., All, and / or the PRR agonist can be done in combination with a secondary drug that helps to increase blood flow in the capillary bed. Suitable secondary drugs may include vasodilators such as nitroglycerin and hydralazine, calcium channel blockers such as amlodipine and nifedipine, ACE inhibitors such as lisinopil and enalapril, angiotensin II receptor blockers such as losartan and valsartan, phosphodiesterase inhibitors such as sildenafil and tadalafil, nitrates such as isosorbide dinitrate and isosorbide mononitrate, prostaglandins such as alprostadil and epoprostenol, pentoxifylline and alpha-blockers such as prazosin and doxazosin.c. Methods Related to Reduction in Muscle Cramping

[0117] In some aspects of the invention, the therapeutically effective amount of a RAS receptor agonist and / or a PRR agonist reduces the frequency and / or severity of ultrafiltration -related cramps in the subject. Frequency of cramps can be assessed by counting the number of cramp events that occur during a ultrafiltration session. In some aspects the method of the invention reduces frequency of cramps such that they occur in less than 50% of subjects, or less than 40% of subjects, or less than 30% of subjects while taking the RAS receptor agonist and / or PRR agonist. In other aspects the method of the invention reduces the frequency of cramps during ultrafiltration to 3 or less, 2 or less, 1 or less, or 0 cramping episodes per subject per ultrafiltration session. Thus disclosed are methods of minimizing the frequency of skeletal muscle cramps in patients undergoing ultrafiltration by administering a RAS receptor agonist and / or a PRR agonist.

[0118] Severity of cramps can be assessed using a pain scale from 1 to 10 classified in 3 categories: minor (1-3), moderate (4-6), and severe (7-10). In some aspects the method of the invention prevents the incidence of severe cramps in the subject while undergoing ultrafiltration. In some aspects the method of the invention prevents the incidence of both moderate and severe cramps in the subject while undergoing ultrafiltration. In other aspects,the method of the invention reduces the incidence of moderate and severe cramps during ultrafiltration to less than 3, or less than 2. or less than 1, or 0 moderate or severe cramping episodes per subject per ultrafiltration session.

[0119] In other aspects of the invention, the therapeutically effective amount of a RAS receptor agonist, e.g., All, and / or a PRR agonist delays the onset of and / or slows the onset of cramps in the subject while undergoing ultrafiltration. Cramps can occur suddenly during ultrafiltration treatment. The administration of a RAS receptor agonist, e.g.. All, and / or a PRR agonist can reduce the incidence of sudden onset of cramping during ultrafiltration. In some aspects, the method of the invention reduces the incidence of sudden onset cramps during ultrafiltration to 3 or less, 2 or less, or 1 or less, or 0 sudden onset cramps per subject per ultrafiltration session.

[0120] Administration of a RAS receptor agonist, e.g.. All, and / or a PRR agonist can also delay the onset of cramping during ultrafiltration. In some embodiments, the delay in onset of cramping ensures that subj ects undergoing ultrafiltration are able to continue the ultrafiltration treatment and avoid discontinuation due to the pain of cramping.

[0121] In yet other aspects of the invention, the therapeutically effective amount of a RAS receptor agonist, e.g., All, and / or a PRR agonist reduces the duration of ultrafiltration-related cramps. The method of the invention provides, in some aspects, a reduction in the duration of cramps in the subject during ultrafiltration to less than 15 minutes, less than 12 minutes, less than 10 minutes, less than 8 minutes, less than 6 minutes, less than 4 minutes, or less than 2 minutes.

[0122] In still yet other aspects of the invention, the therapeutically effective amount of a RAS receptor agonist, e.g., All, and / or a PRR agonist reduces the incidence of muscle cramps during the interval between ultrafiltration treatments. In some aspects, the method of treatment comprising administering a therapeutically effective dose of a RAS receptor agonist, e.g., All, and / or a PRR agonist to a subject undergoing ultrafiltration prevents the incidence of muscle cramps between ultrafiltration treatments.

[0123] In further other aspects of the invention, the therapeutically effective amount of a RAS receptor agonist, e.g., All, and / or a PRR agonist minimizes the location of ultrafiltration-related cramps. The method of the invention, in some aspects, prevents cramps in the lower extremities (e.g., thighs, calves, feet). In some aspects, the method of the invention reduces the incidence of cramps in the lower extremities during ultrafiltration to 3 or less. 2 or less, or 1 or less, or 0 sudden onset cramps per subject per ultrafiltration session. In other aspects, the method of the invention prevents cramps in the upper extremities (e.g..torso / ribs, forearm, hands, fingers). In some aspects, the method of the invention reduces the incidence of cramps in the upper extremities during ultrafiltration to 3 or less, 2 or less, or 1 or less, or 0 sudden onset cramps per subject per ultrafiltration session.d. Methods Related to Improving the Efficacy of Ultrafiltration Treatment

[0124] In yet other aspects of the invention, the administration of a therapeutically effective amount of a RAS receptor agonist, e.g., All, and / or a PRR agonist improves the efficacy of ultrafiltration treatment. In some aspects, the method of the invention prevents or reduces discontinuation or termination of ultrafiltration treatment. Discontinuation or termination of ultrafiltration due to muscle cramping is a challenge for ultrafiltration treatment. The method of the invention reduces the number of times ultrafiltration treatment is discontinued or terminated resulting in improved ultrafiltration care for patients.

[0125] In other aspects, the method provides for reduction in the need for bolus administration of fluid (e.g., sodium chloride solution) to a subject during ultrafiltration. Thus, disclosed are methods of reducing the need for bolus fluid administration to the subject by administering a RAS receptor agonist, e.g.. All, and / or a PRR agonist. Fluid bolus administration during ultrafiltration may be carried out if the subject experiences loss of blood pressure and / or cramping during ultrafiltration. In an aspect of the invention, the administration of a RAS receptor agonist, e.g., AU, and / or a PRR agonist during ultrafiltration treatment can reduce or eliminate the need for any bolus administration of fluid.

[0126] In other aspects, the method provides for reduction in the need to reduce the ultrafiltration goal during ultrafiltration. Thus, disclosed are methods of minimizing the need to reduce the ultrafiltration goal to the subject by administering a RAS receptor agonist, e.g., AU, and / or a PRR agonist. The ultrafiltration is the volume of water that must be removed during ultrafiltration. The administration of a RAS receptor agonist, e.g., AU, and / or a PRR agonist during ultrafiltration reduces or eliminates the need to reduce the ultrafiltration volume.e. Methods Related to Ameliorating Fatigue Associated with Ultrafiltration

[0127] In still other aspects of the invention, the method, in addition to providing each of the above descnbed benefits, further produces improvements in post-ultrafiltration fatigue. Fatigue is a subjective sense of weakness, lack of energy, and tiredness. Fatigue is one of the most frequent complaints of ultrafiltration patients and is associated with reduced quality of life. A majority of ultrafiltration patients undergoing long-term treatment suffer fatigue and fatigue can lead patients to forego more frequent ultrafiltration.

[0128] In some aspects of the invention, RAS receptor agonist, e.g., All, and / or PRR agonist administration can cause reduction and / or elimination of ultrafiltration-related fatigue by reducing or preventing changes in blood pressure, e.g., by preventing onset of reduction in blood pressure (e.g., intradialytic hypotension).f. Methods of Achieving Dry Weight

[0129] While a RAS receptor agonist, e.g., All, and / or a PRR agonist can be used to reduce, e.g., incidence of cramping, this does not mean the effect is sufficient to enable the subject to achieve their target dry weight. Described herein is the ability to achieve a target weight (e.g., dry weight) by preventing all or most undesirable side effects of ultrafiltration.

[0130] Disclosed are methods of achieving dry weight in a subject undergoing ultrafiltration comprising administering to the subject an effective amount of a RAS receptor agonist, e.g., All, and / or a PRR agonist.

[0131] In some aspects, dry weight is the lowest weight a subject undergoing ultrafiltration can tolerate without developing low blood pressure or other cardiac related symptoms. Dry weight can be measured in kilograms and can be a little lower than a healthy person's weight without extra fluid.

[0132] In some aspects, subjects undergoing ultrafiltration suffer cramping so severe that they cannot continue the ultrafiltration and therefore never achieve dry weight. Thus, in some aspects, a subject undergoing ultrafiltration can be treated with a RAS receptor agonist, e.g., All. and / or a PRR agonist to prevent cramping in the subject which would allow ultrafiltration to continue until the subject has reached their target weight (e.g., dry weight).

[0133] In some aspects, administering a RAS receptor agonist, e.g., All, and / or a PRR agonist can also prevent loss of blood pressure (e.g., intradialytic hypotension) to allow' achievement of dry weight. In some aspects, a RAS receptor agonist, e.g., AIL and / or a PRR agonist allow s the subject to maintain blood pressure, thus preventing loss of blood pressure and / or hypotension.

[0134] In some aspects, achieving dry weight can prevent cardiac injury. In some aspects, the removal of so much fluid during ultrafiltration can cause cramping and the subject can respond by producing adrenaline to protect themselves but this response can ultimately lead to cardiac injury. Therefore, allowing a subject to achieve dry weight by administering a RAS receptor agonist, e.g., All, and / or a PRR agonist is due to preventing cramping so severe the ultrafiltration has to stop before dry weight is achieved or is due to preventing cardiac injury or loss of blood pressure (e.g., hypotension) from the ultrafiltration.g. Methods of Preventing Ultrafiltration Induced Microvascular Ischemia

[0135] In yet other aspects of the invention, the administration of a therapeutically effective amount of a RAS receptor agonist, e g., All, and / or a PRR agonist prevents microvascular ischemia in vulnerable organs, including the heart, brain, gut, liver and kidney.

[0136] During ultrafiltration, the brain can suffer from reduced cerebral blood flow, which can result in cognitive decline and white matter injury, often seen as leukoaraiosis. The gastrointestinal tract and liver are also impacted during ultrafiltration, with reductions in blood flow exacerbating gut dysbiosis and endotoxemia (release of toxins from the gut), which further worsens systemic inflammation. Further, despite the dialysis treatment, many patients still have residual kidney function that progressively deteriorates due to microvascular ischemia, increasing their vulnerability to circulatory stress.

[0137] Disclosed are methods of preventing ultrafiltration induced abnormal perfusion or microvascular ischemia to organs and / or damage to vascular beds of organs comprising administering to the subject an effective amount of a RAS receptor agonist, e.g., All, and / or a PRR agonist. Such organs can include, but are not limited to, the brain, kidneys, liver, and gut.

[0138] Such methods include a method of minimizing or preventing injury to the brain, kidney, gut, and / or liver, in patients undergoing ultrafiltration comprising administering to the subject a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

[0139] In some aspects, the methods of the invention reduce the risk of cerebral microvascular ischemia and thereby prevent or mitigate neurocognitive impairment, including memory decline, executive dysfunction, processing speed impairment, and dialysis-related vascular dementia. In certain embodiments, microvascular ischemia in the brain may be measured either via a Positron Emission Tomography (PET) scan or near infrared spectroscopy (NIRS). Neurocognitive outcomes may be assessed by serial neuropsychological testing, including but not limited to, Montreal Cognitive Assessment (MoCA), Trail Making Test, or Wechsler Memory Scale, in patients undergoing ultrafiltration with or without administration of a RAS receptor agonist. Preservation or improvement of test scores over time compared to baseline is an additional measure of treatment efficacy. Imaging biomarkers, such as diffusion tensor MRI or functional MRI, may also be used to demonstrate preserved white matter integrity and reduced ischemic injury. Thus, disclosed are methods of preventing neurocognitive impairment in a patientundergoing dialysis by administering one or more RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV. and / or angiotensin 1-7, and / or a PRR agonist such as prorenin and renin. Such methods optionally further comprise administering a neuropsychological test, e.g., selected from the group consisting of the Montreal Cognitive Assessment (MoCA), the Trail Making Test, or the Wechsler Memory7Scale, one or more times during the course of dialysis, such as, for example, before and / or or after each dialysis session.

[0140] In some aspects, the methods of the invention reduce the risk of renal microvascular ischemia and thereby prevent or mitigate renal injury7and post-dialysis fatigue associated with impaired cortical and medullary perfusion. In certain embodiments, microvascular ischemia in the kidney may be measured using magnetic resonance imaging techniques such as blood oxygen level-dependent MRI (BOLD-MRI), which quantifies changes in tissue oxygenation through R2* mapping, or by contrast-enhanced ultrasound (CEUS), which measures cortical and medullary7blood flow based on time-intensity perfusion curves. Such imaging may be conducted before, during, and after ultrafiltration to assess preservation of renal perfusion following administration of one or more RAS receptor agonists, such as angiotensin II, angiotensin III, angiotensin IV, or angiotensin 1-7, and / or a PRR agonist such as prorenin or renin. In some embodiments, improved renal perfusion correlates with stable or decreased serum creatinine, cystatin C. or urinary NGAL, providing biochemical confirmation of reduced renal ischemia.

[0141] In further aspects, the methods of the invention reduce the risk of hepatic microvascular ischemia and associated hepatic dysfunction during ultrafiltration. In certain embodiments, microvascular perfusion of the liver may be assessed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), which quantifies perfusion parameters such as Ktrans, ve, and area under the contrast curve, or by contrast-enhanced ultrasound (CEUS) to evaluate real-time parenchymal blood flow. In some embodiments, administration of a RAS receptor agonist or PRR agonist during ultrafiltration maintains hepatic perfusion and oxygenation, thereby reducing hepatic enzyme elevation and preserving hepatic synthetic function, as evidenced by stable alanine aminotransferase (ALT), aspartate aminotransferase (AST), and albumin levels.

[0142] In additional aspects, the methods of the invention reduce the risk of gastrointestinal or splanchnic microvascular ischemia, which may contribute to dialysis-related hypotension, nausea, and endotoxemia. In certain embodiments, gut microvascular ischemia may be measured or visualized using indocyanine green (ICG) fluorescenceangiography, which provides a direct measure of mucosal perfusion, or by gastric tonometry, which measures the mucosal-arterial PCO2 gradient as an indirect indicator of intestinal hypoperfusion. Alternatively, sublingual or mucosal microcirculation may be assessed using sidestream dark field (SDF) or incident dark field (IDF) videomicroscopy, providing quantifiable metrics of capillary density and flow (e.g., microvascular flow index, perfused vessel density, and proportion of perfused vessels). Thus, disclosed are methods of preventing renal, hepatic, and gastrointestinal microvascular ischemia in a patient undergoing dialysis by administering one or more RAS receptor agonists such as angiotensin II, angiotensin III, angiotensin IV, and / or angiotensin 1-7, and / or a PRR agonist such as prorenin or renin, optionally in conjunction with imaging or physiological monitoring of organspecific microcirculatory perfusion.

[0143] Taken together, the foregoing aspects illustrate that ultrafiltration can induce systemic microvascular ischemia affecting multiple organ systems, including the brain, heart, kidneys, liver, and gastrointestinal tract. Such ischemia arises from transient hypovolemia, sympathetic activation, and catecholamine surge, leading to regional vasoconstriction and reduced capillary perfusion. The methods disclosed herein provide a means of preventing or mitigating these effects by pharmacologically preserving microvascular flow and tissue oxygen delivery. Administration of one or more RAS receptor agonists and / or PRR agonists during ultrafiltration maintains perfusion across critical vascular beds, thereby reducing ischemic injury, preventing downstream organ dysfunction, and improving overall hemodynamic stability and treatment tolerance. Accordingly, the invention encompasses methods of preventing systemic microvascular ischemia in a subject undergoing dialysis or ultrafiltration by administering a therapeutically effective amount of one or more RAS receptor agonists such as angiotensin II, angiotensin III. angiotensin IV, and / or angiotensin 1-7, and / or a PRR agonist such as prorenin or renin, thereby maintaining capillary perfusion and preventing multi-organ ischemic injury.G. Pharmaceutical Compositions

[0144] Suitable formulations (pharmaceutical compositions) for administering a RAS receptor agonist, e.g., All, and / or a PRR agonist will depend on the mode of administration. For example, formulations adapted for parenteral administration may comprise a sterile aqueous preparation, preferably isotonic with the blood of the recipient. This aqueous preparation may be formulated according to known methods using suitable dispersing or wetting agents and suspending agents. The preparation also may be a sterile injectable solution or suspension in a diluent or solvent, for example as a solution with mannitol, 1,3-butanediol, water, Ringer's solution, and isotonic sodium chloride solution, which are exemplary acceptable diluents. Sterile, fixed oils may be employed as a solvent or suspending medium. Bland fixed oils, including synthetic mono or di-glycerides, and fatty acids, such as oleic acid, may also be used. Most of the agents described herein are commercially available and can be obtained readily from commercial sources.

[0145] The pharmaceutical compositions of the present invention may also contain diluents, fillers, salts, buffers, stabilizers, solubilizers, and other materials well known in the art. The term "pharmaceutically acceptable carrier" refers to anon-toxic carrier that may be administered to a patient, together with a therapeutically effective substance (such as angiotensin II) of this invention, and which does not destroy the pharmacological activity' of the therapeutically effective substance. The term "pharmaceutically acceptable" means anon-toxic material that does not interfere with the effectiveness of the biological activity of the active ingredient(s). The characteristics of the carrier will depend on the route of administration. The term "excipient" refers to an additive in a formulation or composition that is not a pharmaceutically active ingredient. One of skill in the art would appreciate that the choice of any one excipient may influence the choice of any other excipient. For example, the choice of a particular excipient may preclude the use of one or more additional excipients because the combination of excipients would produce undesirable effects. One of skill in the art would be able to empirically determine which excipients, if any, to include in the compositions of the invention. Excipients of the invention may include, but are not limited to, co-solvents, solubilizing agents, buffers, pH adjusting agents, bulking agents, surfactants, encapsulating agents, tonicity-adjusting agents, stabilizing agents, protectants, and viscosity modifiers. In some aspects, it may be beneficial to include a pharmaceutically acceptable carrier in the compositions of the invention.

[0146] In some aspects, it may be beneficial to include a solubilizing agent in the compositions of the invention. Solubilizing agents may be useful for increasing the solubility of any of the components of the formulation or composition, including a therapeutically effective substance (e.g.. angiotensin II and / or catecholamine) or an excipient. The solubilizing agents described herein are not intended to constitute an exhaustive list, but are provided merely as exemplary solubilizing agents that may be used in the compositions of the invention. In certain aspects, solubilizing agents include, but are not limited to, ethyl alcohol, tert-butyl alcohol, polyethylene glycol, glycerol, methylparaben, propylparaben, polyethylene glycol, polyvinyl pyrrolidone, and any pharmaceutically acceptable salts and / or combinations thereof.

[0147] In some aspects, it may be beneficial to adjust the pH of the compositions by including a pH-adjusting agent in the compositions of the invention. Modifying the pH of a formulation or composition may have beneficial effects on, for example, the stability or solubility of a therapeutically effective substance, or may be useful in making a formulation or composition suitable for parenteral administration. pH-adjusting agents are well known in the art. Accordingly, the pH-adjusting agents described herein are not intended to constitute an exhaustive list, but are provided merely as exemplary pH-adjusting agents that may be used in the compositions of the invention. pH-adjusting agents may include, for example, acids and bases. In some aspects, a pH-adjusting agent includes, but is not limited to, acetic acid, hydrochloric acid, phosphoric acid, sodium hydroxide, sodium carbonate, and combinations thereof.

[0148] The pH of the compositions of the invention may be any pH that provides desirable properties for the formulation or composition. Desirable properties may include, for example, therapeutically effective substance (e.g., angiotensin II) stability', increased therapeutically effective substance retention as compared to compositions at other pHs, and improved filtration efficiency. In some aspects, the pH of the compositions of the invention may be from about 3.0 to about 9.0, e.g., from about 5.0 to about 7.0. In particular aspects, the pH of the compositions of the invention may be 5.5±0.1, 5.6±0.1, 5.7±0.1, 5.8±0.1, 5.9±0.1, 6.0±0.1. 6. l±0.1, 6.2±0.1, 6.3±0.1, 6.4±0.1, or 6.5±0.1.

[0149] In some aspects, it may be beneficial to buffer the pH by including one or more buffers in the compositions. In certain aspects, a buffer may have a pKa of, for example, about 5.5, about 6.0, or about 6.5. One of skill in the art would appreciate that an appropriate buffer may be chosen for inclusion in compositions of the invention based on its pKa and other properties. Buffers are well known in the art. Accordingly, the buffers described herein are not intended to constitute an exhaustive list, but are provided merely as exemplary buffers that may be used in the compositions of the invention. In certain aspects, a buffer may include one or more of the following: Tris, Tris HC1, potassium phosphate, sodium phosphate, sodium citrate, sodium ascorbate, combinations of sodium and potassium phosphate, Tns / Tris HC1, sodium bicarbonate, arginine phosphate, arginine hydro-chloride, histidine hydrochloride, cacodylate, succinate, 2-(N-morpholino)ethanesulfonic acid (MES), maleate, bis-tris methane, phosphate, carbonate, and any pharmaceutically acceptable salts and / or combinations thereof.

[0150] In some aspects, it may be beneficial to include a surfactant in the compositions of the invention. Surfactants, in general, decrease the surface tension of a liquidcomposition. This may provide beneficial properties such as improved ease of filtration. Surfactants also may act as emulsifying agents and / or solubilizing agents. Surfactants are well known in the art. Accordingly, the surfactants described herein are not intended to constitute an exhaustive list, but are provided merely as exemplary surfactants that may be used in the compositions of the invention. Surfactants that may be included include, but are not limited to, sorbitan esters such as polysorbates (e.g., polysorbate 20 and polysorbate 80), lipopolysaccharides, polyethylene glycols (e.g., PEG 400 and PEG 3000), poloxamers (i.e., pluronics), ethylene oxides and polyethylene oxides ( e.g., Triton X-100), saponins, phospholipids (e.g., lecithin), and combinations thereof.

[0151] In some aspects, it may be beneficial to include a tonicity-adjusting agent in the compositions of the invention. The tonicity of a liquid composition is an important consideration when administering the composition to a patient, for example, by parenteral administration. Tonicity-adjusting agents, thus, may be used to help make a formulation or composition suitable for administration. Tonicity -adjusting agents are well known in the art. Accordingly, the tonicity-adjusting agents described herein are not intended to constitute an exhaustive list, but are provided merely as exemplary tonicity-adjusting agents that may be used in the compositions of the invention. Tonicity-adjusting agents may be ionic or nonionic and include, but are not limited to, inorganic salts, amino acids, carbohydrates, sugars, sugar alcohols, and carbohydrates. Exemplary inorganic salts may include sodium chloride, potassium chloride, sodium sulfate, and potassium sulfate. An exemplary amino acid is glycine. Exemplary sugars may include sugar alcohols such as glycerol, propylene glycol, glucose, sucrose, lactose, and mannitol.

[0152] In some aspects, it may be beneficial to include a stabilizing agent in the compositions of the invention. Stabilizing agents help increase the stability of a therapeutically effective substance in compositions of the invention. This may occur by, for example, reducing degradation or preventing aggregation of a therapeutically effective substance. Without wishing to be bound by theory, mechanisms for enhancing stability may include sequestration of the therapeutically effective substance from a solvent or inhibiting free radical oxidation of the anthracy cline compound. Stabilizing agents are well known in the art. Accordingly, the stabilizing agents described herein are not intended to constitute an exhaustive list, but are provided merely as exemplary stabilizing agents that may be used in the compositions of the invention. Stabilizing agents may include, but are not limited to, emulsifiers and surfactants.

[0153] The compositions of the invention can be administered in a variety' of conventional ways. In some aspects, the compositions of the invention are suitable for parenteral administration. These compositions may be administered, for example, intraperitoneally, intravenously, intra-arterially, intra-renally, or intrathecally. In some aspects, the compositions of the invention are injected intravenously. One of skill in the art would appreciate that a method of administering a therapeutically effective substance formulation or composition of the invention would depend on factors such as the age, weight, and physical condition of the patient being treated, and the disease or condition being treated. The skilled worker would, thus, be able to select a method of administration optimal for a patient on a case-by-case basis.

[0154] The pharmaceutical compositions can be sterile and sterilized by conventional sterilization techniques or sterile filtered. Aqueous solutions can be packaged for use as is, or lyophilized, the lyophilized preparation, which is encompassed by the present disclosure, can be combined with a sterile aqueous carrier prior to administration. The pH of the pharmaceutical compositions typically will be between 3 and 11 (e.g., between about 5 and 9) or between 6 and 8 (e.g., between about 7 and 8). The resulting compositions in solid form can be packaged in multiple single dose units, each containing a fixed amount of the above-mentioned agent or agents, such as in a sealed package of tablets or capsules. The composition in solid form can also be packaged in a container for a flexible quantity, such as in a squeezable tube designed for a topically applicable cream or ointment.

[0155] In one embodiment, glass vials containing 50 pg angiotensin II (All) packaged under inert gas (for example, supplied by Bachem) are used, along with pumps for administering All infusions. All is reconstituted in 5% DAV and added to a 250 mL glass bottle of 5% D / W to give a final concentration of Dose x Patient Weight (in kg) per mL, where Dose initially is 1 ng / kg or 2 ng / kg, but may subsequently be between 1 and 5 ng / kg or 1 and 10 ng / kg (for example, 3, 5, or 10 ng / kg), as specified by the protocol. The infusion pump delivers infusions at a rate of 0.5 mL / min or 1 mL / min but may be altered to deliver less than 0.5 mL / min or as much as 2 mL / min, as needed. The infusion rate may be lowered to 0.5 mL / min should systolic pressure rise more than 15 mm Hg. It may be preferred to use infusion pumps that are accurate at lower infusion rates, in which case the dissolved Dose would be correspondingly increased.

[0156] Similar formulations can be prepared for other RAS receptor agonists and / or PRR agonists.

[0157] The following examples are included to illustrate the invention, but the invention should not be understood to be limited to these exemplified embodiments.EXAMPLE

[0158] The effectiveness of treating patients undergoing intermittent hemodialysis (IHD) with Angiotensin II to improve patient outcomes was demonstrated.

[0159] A pilot, single-blinded, placebo-controlled, randomized cross-over trial to assess the safety and efficacy of angiotensin II infusion as a means to prevent muscle cramps in IHD patients with a history7of frequent intradialytic cramps was conducted at Austin Hospital in Australia from August 2023 to March 2024. Adult patients (aged >18 years) receiving maintenance hemodialysis (3 times per week) were eligible for inclusion if they had appropriate dialysis access (arteriovenous fistula [AVF], arteriovenous graft [AVG] or permanent catheter) and a recent history7of painful muscle cramps, defined by early termination of a dialysis session due to muscle cramps in the previous month or reduction in prescribed ultrafiltration or administration of fluid due to muscle cramps in the previous month.

[0160] Exclusion criteria included (1) know n or suspected allergy to components of angiotensin II, (2) presently taking an angiotensin II receptor blocker, (3) history of intracerebral haemorrhage, (4) history of heart failure with a left ventricular ejection fraction (LVEF) less than 20%, (5) pre-dialysis systolic blood pressure (SBP) greater than 180 mmHg, or (6) any other disease or significant lab result abnormality that, according to the investigator, could compromise participant safety7, interfere with trial participation, or impact the trial objectives. Patients eligible for the study were selected from lists of outpatients receiving hemodialysis. Those who fulfilled all inclusion criteria and none of the exclusion criteria were enrolled in the trial after obtaining informed consent.

[0161] Patients were randomly assigned in a 1: 1 ratio to receive either angiotensin II or placebo (0.9% saline) during their first dialysis treatment of the week, based on a computer-generated list. Randomization was performed using an online research electronic data capture (REDCap Consortium, Vanderbilt University', Nashville, TN database). Patients alternated between receiving angiotensin II or placebo during their first dialysis treatment of the week for a total of four w eeks. Each participant completed two dialysis treatments with angiotensin II and two dialysis treatments with placebo, providing a balanced exposure to both interventions across the study period. Patients and dialysis nurses were blinded to groupallocation. An unblinded investigator of the research team was responsible for preparing and administering the study drug infusion.

[0162] In sessions assigned to the intervention group, patients were administered a continuous infusion of angiotensin II. To prepare the study infusion for the intervention arm, 1 mL was w ithdraw n from a 500 rnL bag of 0.9% sodium chloride and replaced with 1 mL of angiotensin II (2.5 mg), achieving a final concentration of 5000 pg / L (5 pg / rnL). The infusion for the study drug began within 15 minutes of starting the dialysis session, at an initial prescribed dose of 1 ng / kg / min. The infusion rate was increased in increments of 0.5 to 2 ng / kg / min every 15-minutes. The process was continued until the dose reached the maximum rate of 30 ng / kg / min or the systolic blood pressure reached 180 mmHg. The goal was to deliver angiotensin II at the maximum tolerated dose between 1 to 30 ng / kg / min while maintaining a SBP between 100 to 180 mmHg. If the SBP increased above 180 mmHg, the infusion was paused for 15 minutes and restarted if the SBP fell below 180 mmHg.Adjustments to the infusion rates were handled by a member of the study team.

[0163] For sessions assigned to the control group, patients receive a continuous placebo infusion of 0.9% saline in a 500 mL bag. The titration protocol of the placebo was identical to active drug.

[0164] Demographic data including age, sex, comorbidities, etiology7of end-stage-kidney -disease (ESKD), and baseline laboratories parameters were collected. Dialysis prescriptions include modality, blood flow rate (BFR), dialysate flow rate (DFR), duration, ty pe of vascular access, anticoagulation, ultrafiltration rate, target weight, pre- and postdialysis weight w ere also collected. Intensity7of muscle cramps w as evaluated using the Brief Pain Inventory (BPI), employing a scale from 1 to 10, where 1 indicates minimal pain and 10 represents the most severe pain.

[0165] Hemodynamic parameters were collected at baseline and every 15 minutes until dialysis cessation by the ClearSight device (Edwards Lifesciences, Irvine, CA) and included SBP, diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), and cardiac index (CI). Troponin I, creatine kinase, and plasma renin activity were collected pre- and post-dialysis.

[0166] The primary outcome was the safety and tolerability of angiotensin II, defined as the incidence of local and / or systemic adverse events including: (1) intradialytic hypertension, which was defined as a significant increase in SBP to over 180 mmHg during a dialysis session, necessitating intervention, (2) access thrombosis, (3) venousthromboembolic event, or (4) arterial thromboembolic event. Evidence of adverse events was identified from patients, dialysis nursing charts, and the medical record.

[0167] The secondary efficacy outcomes were (1) occurrence of painful muscle cramps, (2) muscle cramp intensity as assessed by the BPI, (3) hemodialysis treatment alteration due to muscle cramps (e.g., fluid bolus administration, reduction in ultrafiltration goal, or treatment termination), (4) intradialytic hypotension defined as a decrease in SBP >20 mmHg or SBP <90 mmHg, (5) adverse intradialytic symptoms (e.g., abdominal pain, nausea, vomiting, restlessness, dizziness, fainting, “going flat”). The secondary safety outcomes were changes in hemodynamic parameters (SBP, DBP, MAP, HR, CO, CI) and change in cardiac, muscle and RAAS biomarkers (troponin I, creatine kinase, and renin) from pre- to post-dialysis.

[0168] Based on feasibility, we aimed to include a convenience sample of 6 patients with total 24 sessions and approximately 50 hours of angiotensin II infusion in this pilot study. Descriptive statistics were used to summarize data. Numerical data were presented as frequencies and percentages (%), normally distributed data were presented as means and standard deviations (SD), and skewed data were presented as medians and interquartile ranges (IQR).

[0169] Baseline characteristics were compared using Fisher’s exact test, the unpaired t-test, or the Mann- Whitney U test, as appropriate. For comparison of parameters during the intervention and outcomes between two groups, analyses were made using the paired t-test, Wilcoxon signed-rank test, or McNemar’s test depending on datatype. Linear mixed models were constructed with time as a random effect to assess for the interaction between group assignment and pain score, drug dosage, SBP, DBP, MAP, HR, CO, and CI. All analyses were performed using R version 4.2.3 (R Foundation for Statistical Computing) and a two-sided p-value less than 0.05 was considered statistically significant.

[0170] From 1 August 2023 to 30 March 2024 a total of 12 patients were screened for eligibility. Six patients were excluded since they were ineligible (n=2) or declined to participate (n=4). The remaining 6 patients were randomized and completed a total of 24 study dialysis sessions (Figure 1).

[0171] Baseline characteristics of the study population according to their initial allocation are shown in Table 1.1. Table 1. Baseline characteristics of study participantsStudy participants Characteristics. „. Angiotensin IIAll (n =6)&_ Placebo (n = 3) Age (years) 68.2±5.6 65.3±6.7 71±3.5 Sex. n (%)Male 4 (66.7) 2 (66.7) 2 (66.7) Female 2 (33.3) 1 (33.3) 1 (33.3) Comorbidities, n (%)Hypertension 6 (100) 3 (100) 3 (100) Cardiovascular disease 3 (50) 2 (66.7) 1 (33.3) Chronic lung disease 3 (50) 1 (33.3) 2 (66.7) Chronic liver disease 1 (16.7) 0 (0) 1 (33.3) Cancer 1 (16.7) 0 (0) 1 (33.3) Cause of ESKD, n (%)ADPKD 1 (16.7) 0 (0) 1 (16.7) ANCA-associated GN 1 (16.7) 1 (33.3) 0 (0) Diabetic nephropathy 1 (16.7) 0 (0) 1 (33.3) Membranous nephropathy 1 (16.7) 0 (0) 1 (33.3) Reflux nephropathy 2 (33.3) 2 (66.7) 0 (0) Vascular access site, n (%)Arteriovenous fistula 2 (33.7) 0 (0) 2 (66.7) Arteriovenous graft 1 (16.7) 1 (33.3) 0 (0) Permanent catheter 3 (50) 2 (66.7) 1 (33.3) RAAS inhibitor usage, n (%) 1 (16.7) 0 (0) 1 (33.3) Residual urine output, ml / day 0 (0-75) 0 (0-50) 0 (0-50) Dialysis vintage, yr 5.6 (2-9.2) 8.3 (4.4-10.9) 2.8 (2.2-6.2) LaboratoriesUrea. mmolL 17.06±3.68 17.4±4.9 16.7±3.1 Cr, pmol / L 648.3±231.5 619.3±344.5 677.3±113.2 Potassium, mmol / L 4.5±1.0 4.5±1.3 4.5±1.1 Phosphate, mmol / L 1.6±0.5 1.4±0.5 1.8±0.6 Albumin, g / dL 28.8±3.6 30.7±1.2 27±4.6 Hemoglobin, g / L 100.7±17.9 109±24.2 92.3±2.1 Values are presented as n (%), mean±SD, and median (IQR)Abbreviations: ADPKD, autosomal dominant polycystic kidney disease; ANCA, antineutrophil cytoplasmic antibodies; Cr. creatinine; ESKD. end stage kidney disease; RAAS, renin angiotensin aldosterone system.

[0172] The mean age was 68.2 years, and the median dialysis vintage was 5.6 years. The most common comorbidities were hypertension, cardiovascular disease, and chronic lung disease. Only one patient was normally on chronic angiotensin receptor blockers (ARBs) therapy but had stopped such therapy for clinical reasons during the study period. There were no significant differences between groups in terms of baseline demographic, laboratory, hemodynamic or dialysis parameters (Table 2).Table 2. Characteristics of dialysis and clinical parameters according to treatment assignment _Angiotensin II Placebo p value (12 sessions) (12 sessions)Pre-dialysis parametersSBP, mmHg 134.2±16.2 123.2±20.8 0.161 DBF. mmHg 58.9±I0.7 55.8±9.9 0.474 MAP, mmHg 79.2±11.3 79.1±11 0.985 HR, / min 68.1±I0.3 68.4±11.2 0.940 CO, L / min 4.9±0.9 4.2±L1 0.149 CI 2.5±0.7 2.5±0.3 0.956 Post-dialysis parametersSBP. mmHg 139.1±21.2 133.3±32.5 0.608 DBP, mmHg 65.4±12.5 64.9±13.3 0.925 MAP, mmHg 87.8±I6.7 88.8±15.3 0.880 HR, / min 84.7±8.5 78.8±9.9 0.134 CO, mm 4.5±0.9 4.5±1.1 0.938 CI 2.4±0.6 2.4±0.3 0.356 Dialysis prescriptionDialysis time, h 4.5 (4-4.5) 4.5 (4-4.5) 1 Blood flow rate, mL / min 300 (300-300) 300 (300-300) 0.514 Dialysate flow rate, mL / min 500 (500-500) 500 (500-500) 1 Anticoagulation, n (%) 0.605 No 2 (16.7) 4 (33.3)Heparin 4 (33.3) 3 (25) Enoxaparin 6 (50) 5 (41.7) Ultrafiltration rate, mL / kg / hr 10.1 (7.0-10.7) 9.2 (8.2-10.0) 0.686 Total ultrafiltration volume, mL 2760 (2300-3925) 2925 (2375-3625) 0.912 Target weight, kg 69.8 (65.4-88.1) 69.8 (65.2-88.1) 0.976 Pre-dialysis weight, kg 74.1 (66.9-90.8) 74 (66.8-91.7) 0.977 Post-dialysis weight, kg 71.1 (65.4-88.6) 71 (65.6-88.6) 0.908 Volume and dose of study drugTotal drug volume, mL 7.8 (3.8-21.5) 33.2 (29.1-57.6) <0.001” Maximal drug dosing, ng / kg / min 2.5 (1 6-4.8) 16.6 (10-30) <0.001* Values are presented as n (%), mean±SD, and median (IQR)Abbreviations: CO, cardiac output; DBF, diastolic blood pressure; HR, heart rate; MAP, mean arterial pressure; SBP, systolic blood pressure" / ’-value < 005 is statistically significant

[0173] The total volume of study drug and maximum drug dosage were lower with angiotensin II treatments compared to placebo treatments (median, 7.8 ml vs 33.2 ml.<0.001) and (2.5 ng / kg / min vs 16.6 ng / kg / min, / ’<().001 ). respectively. Additionally, the drug dosage varied less during angiotensin II treatments compared to placebo treatments (^=0.002) (Figure5).

[0174] Intradialytic hypertension occurred during 4 angiotensin II sessions and 2 placebo sessions (33% vs 17%, =0.64). No patients developed access thrombosis, venous thrombosis, or arterial thrombosis (Table 3).Table 3. Adverse event and IHD-related muscle cramps according to treatment assignment _Angiotensin II Placebo „. (12 sessions) (12 sessions)va ueAdverse events related to angiotensin 11, n (%)Intradialytic hypertension 4 (33.3) 2 (16.7) 0.640 Access thrombosis 0 (0) 0 (0) 1.00 Venous thrombosis (DVT or 0 (0) 0 (0)PE)1 UUArterial thrombosis (AMI or 0 (0) 0 (0)CVA) IHD-related muscle crampOccurrence of cramps, n (%) 4 (33.3) 11 (91.6) 0.009" Time to first cramps symptom, h 3.5±0.9 2.9±1.2 0.353 Total episodes of cramps persession1 episode 4 (100) 7 (63.6) 0.413 2 episodes 0 (0) 2 (18.2) 0.478 3 episodes 0 (0) 0 (0) 1.00 4 episodes 0 (0) 2 (18.2) 0.478 Average intensity per sessions** 1.4±2.1 5.3±2.6 <0.001“ Maximal intensity per session** 1.4±2.1 6±2.9 <0.001" Hemodialysis treatment alteration due to crampNo changes (maintain same 3 (25) 2 (16.7)treatment) Fluid bolus administration 0 (0) 5 (41.7) 0.037" Reduction in ultrafiltration goal 1 (83) 5 (41.7) 0.220 Dialysis termination 0 (0) 1 (8.3) 1.00 Intradialytic symptoms 0 (0) 0 (0) 1.00 Intradialytic hypotension 0 (0) 0 (0) 1.00 Values are presented as n (%), mean±SDAbbreviations: AMI, acute myocardial infarction; CVA, cerebrovascular disease; DVT, deep vein thrombosis; IHD, intermittent hemodialysis; PE, pulmonary embolism *P-value < 005 is statistically significant **BPI (Brief Pain Inventory) was used to evaluate intensity by rating pain score on a scale ranging from 0 to 10.

[0175] There was a significantly lower occurrence of intradialytic cramps with angiotensin II compared to placebo (30% vs 90%. =0.009). No patients experienced more than one cramp per session with angiotensin II, compared to one to four cramps per session with placebo (Table 3). Cramps were also less intense with angiotensin II compared to placebo (median BPI 1.4 vs 5.3, P <0.001; maximum BPI 1.4 vs 6.0, P <0.001). Moreover, on linear mixed modelling, angiotensin II was associated with a statistically significant reduction in pain scores overtime during dialysis compared to the placebo (P=0.002) (Figure 2). The single patient treated with an ARBs reported no muscle cramps in the angiotensin II group and severe reported muscle cramps with placebo. Cramps were localized predominantly in the lower limbs, especially in the calf (Figure 3). Fluid bolus administration occurred more frequently with placebo than with angiotensin II (42% vs 0%, P=0.037) and there was a trend towards ultrafiltration reduction during placebo compared to angiotensin II (41.7% vs. 8.3%, =0.22, Table 2).

[0176] SBP, MAP, DBP, and HR increased more over time with angiotensin II compared to placebo (SBP 15.9 mmHg, MAP 13.2 mmHg, DBP 9.7 mmHg, all P<0.001; HR 3 bpm, P=0.028) (Figure 4). There were no significant differences between groups in terms of CO or CI when assessed over the entire treatment period (Figure 6 and Figure 7).Changes in troponin I, creatine kinase, and renin before were also not significantly different when assessed before and after treatment (Figures 8-10). During the initial 60 minutes there was a significant difference with the angiotensin II group showing maintenance of systolic blood pressure, cardiac output and cardiac index while the placebo group showed a decline in systolic blood pressure, cardiac output and cardiac index (Table 4).Table 4. Dialysis parameters after 45 and 60 minutesAngiotensin II effect v. Angiotensin II effect v. placebo after 45 minutes placebo after 60 minutes) Dialysis parametersSBP, mmHg +17.23 +18.7902=0.016*) DBP. mmHg +2.5 +4.9702=0.086) MAP. mmHg +6.31 + 11.4402=0.004*) HR, / min +0.25 +0.37 02=0.84) CO, L / min +0.678 +0.533 02=0.059) CI, L / min / m2+0.351 +0.28202=0.05*) RBV change (%) +0.39+0.229 02=0.702) Values are presented as n (%), mean±SD, and median (IQR)Abbreviations: CO, cardiac output; DBP, diastolic blood pressure; HR, heart rate; MAP, mean arterial pressure; SBP, systolic blood pressure" / ’-value < 0.05 is statistically significant

[0177] This pilot, single-blinded, placebo-controlled, randomized crossover trial of maintenance IHD patients who frequently experienced intradialytic muscle cramps demonstrated that infusion of angiotensin II during dialysis is safe and effective to decrease the frequency and intensity' of cramps. Additionally, this study demonstrated that angiotensin II administration is effective to decrease the need for fluid bolus administration and increase blood pressure and heart rate, without significant impact on cardiac or muscle injury biomarkers or serum renin levels.

[0178] Despite the increase in blood pressure we observed with angiotensin II compared to placebo, there was no difference in the incidence of intradialytic hypertension between groups. Conversely, angiotensin II may have enhanced hemodynamic status in these patients since fewer patients receiving angiotensin II required fluid bolus administration during their treatment. Because the optimal dosing and titration regimen for the prevention of cramps in patients undergoing IHD was unknown, we opted for a lower starting dose of 1 ng / kg / min and implemented a cautious regimen aimed at ensuring blood pressure stability. The median maximal dose required to achieve a satisfactory’ hemodynamic response (defined as a SBP between 100 and 180 mmHg) was 2.5 ng / kg / min.

[0179] These findings support that infusion of angiotensin II during ultrafiltration may prevent or restore physiological responses to the volume stress caused by ultrafiltration and prevent skeletal muscle hypoperfusion and ischemia. These findings further support that low dose angiotensin II infusion is safe in IHD patients and is effective to prevent or reduce the frequency and pain intensity of intradialytic muscle cramps. Moreover, they confirm the effect of angiotensin II on blood pressure and support that such treatment may decrease the use of fluid bolus therapy during IHD. Finally, they support that the increase in blood pressure with angiotensin II does not adversely affect cardiac output.

[0180] While the present invention has been described with reference to what are presently considered to be the preferred examples, it is to be understood that the invention is not limited to the disclosed examples. To the contrary7, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0181] All publications, patents, and patent applications are herein incorporated by reference in their entirety’ to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety. Where a term in the present application is found to be defined differently in a document incorporated herein by reference, the definition provided herein is to serve as the definition for the term.

Claims

CLAIMS1. A method of minimizing or preventing microvascular ischemia in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist and optionally one or more vasodilators.

2. A method of minimizing or preventing a decline in blood pressure in a patient undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or an agonist of the prorenin receptor (PRR).

3. A method of maintaining cardiac output in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

4. A method of minimizing or preventing cardiac muscle injury and / or an increase in biomarkers of cardiac injury such as troponin I or creatine kinase-mb in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

5. A method of minimizing or preventing cardiac stunning in a patient undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

6. A method of minimizing or preventing cardiovascular dysfunction in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

7. A method of minimizing or preventing ultrafiltration fatigue in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

8. A method of minimizing or preventing brain injury in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

9. A method of minimizing or preventing kidney injury' in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

10. A method of minimizing or preventing injury' to the gut in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

11. A method of minimizing or preventing injury to the liver in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

12. A method of minimizing the need to reduce the ultrafiltration goal in a patient undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

13. A method of minimizing the need to discontinue or terminate ultrafiltration in a patient undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

14. A method of achieving dry weight in a subject undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

15. A method of reducing the need for bolus fluid administration in a patient undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

16. A method of minimizing the frequency of skeletal muscle cramps in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

17. A method of minimizing the severity' and intensity of skeletal muscle cramps in a patient undergoing ultrafiltration in a patient undergoing ultrafiltration comprisingadministering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

18. A method of preventing termination of ultrafiltration due to the severity of muscle cramps comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

19. A method of delaying the onset of skeletal muscle cramps in patients undergoing ultrafiltration comprising administering to the subject undergoing ultrafiltration a therapeutically effective amount of one or more RAS receptor agonists and / or a PRR agonist.

20. The method of any one of claims 16-19, wherein the subject experiences 2 or less cramps per ultrafiltration session, wherein the subject experiences 1 or less severe cramps per ultrafiltration session, and / or wherein the subject experiences 1 or less cramps in the upper extremities.

21. The method of any one of claims 1-20, wherein the administration of agonist(s) targeting receptors of the RAS and / or the PRR prevents catecholamine surge during the ultrafiltration.

22. The method of any one of claims 1-21, wherein the method further prevents microvascular ischemia.

23. The method of any one of claims 1-22, wherein the RAS receptor agonist is angiotensin II.

24. The method of any one of claims 1-23, wherein the RAS receptor agonist comprises an ATR1 and / or ATR2 receptor agonist administered in combination with a Mas receptor agonist and / or a PRR agonist.

25. The method of any one of claims 1-24, wherein the RAS receptor agonist is [125I][Sarl] angiotensin II, [125I][Sar', Ile8]-angiotensin II, [Sarl, Cha8] angiotensin- II, [Sarl, Cha4] angiotensin II, [Sarl, Ile8] angiotensin II, [Sari, Ala8] -angiotensin II), [p-aminoPhe6] angiotensin II, angiotensin 1-7, angiotensin III, angiotensin A, CGP42H2, angiotensin IV, AVE-0991, novokinin, Compound 21, Compound 38, L- 163,101, L-162,313, TRV023, TRV026, LVV-hemorphin, AR234958, AR234960, or a combination thereof.

26. The method of any one of claims 1-25, wherein the therapeutically effective amount of RAS receptor agonist and / or PRR agonist is administered to the subject at the start of the ultrafiltration procedure.

27. The method of any one of claims 1-26, wherein the therapeutically effective amount of the RAS receptor agonist and / or the PRR agonist is administered to the subject by continuous infusion.

28. The method of any one of claims 1-27, wherein the therapeutically effective amount of the RAS receptor agonist and / or the PRR agonist is administered to the subject by continuous infusion with pauses in the infusion.

29. The method of any one of claims 27-28, wherein the infusion occurs in the extracorporeal circuit.

30. The method of any one of claims 1-29, wherein the therapeutically effective amount of the RAS receptor agonist and / or the PRR agonist is administered to the subject at doses sufficient to maintain adequate blood pressure and prevent a compensatory catecholamine release during ultrafiltration.

31. The method of any one of claims 1-30, wherein the therapeutically effective amount of the RAS receptor agonist and / or the PRR agonist is administered to the subject at a low dose.

32. The method of any one of claims 1-31, wherein the therapeutically effective amount of the RAS receptor agonist and / or the PRR agonist is administered to the subject by continuous infusion at a rate between about 0.1 ng / kg / min and about 20 ng / kg / min of body weight of the subject.

33. The method of any one of claims 1-32, wherein the starting dose of the RAS receptor agonist and / or the PRR agonist is about 1-10 ng / kg / min by continuous infusion.

34. The method of any one of claims 1-33, wherein the starting dose of the RAS receptor agonist and / or the PRR agonist is about 1-5 ng / kg / min by continuous infusion.

35. The method of any one of claims 1-34, wherein the therapeutically effective amount of the RAS receptor agonist and / or the PRR agonist is administered to the subject by continuous infusion at an initial rate of 1 ng / kg / min.

36. The method of claim 35, wherein after 15 minutes the infusion rate is increased in increments of 0.5 to 5 ng / kg / min every 15 minutes until either the systolic blood pressure reaches 180 mmHg or a maximum infusion rate of 20 ng / kg / min is reached.

37. The method of any one of claims 27-36, wherein the median infusion rate of the RAS receptor agonist and / or the PRR agonist administered to the subject is about 2.5 ng / kg / min.

38. The method of claim 27-37, wherein the infusion rate of the RAS receptor agonist and / or the PRR agonist does not exceed 10 ng / kg / min.

39. The method of any one of claims 1-38, wherein the therapeutically effective amount of the RAS receptor agonist and / or the PRR agonist is administered to the subject within 15 minutes to 3 hours before or after the start of the ultrafiltration session.

40. The method of any one of claims 16-19, wherein the therapeutically effective amount of the RAS receptor agonist and / or the PRR agonist is administered to the subject within 15 minutes before or after the onset of cramps in previous ultrafiltration sessions.

41. The method of any one of claims 16-19 and 40, wherein the method further provides for a delay in the onset of dialytic cramps during ultrafiltration, wherein the subject does not experience a cramp until at least 50%, at least 60%, at least 70%, at least 80% or at least 90% of the ultrafiltration treatment session has been completed.

42. The method of any one of claims 1-41, wherein the method further provides for maintenance of the cardiac index of the subject during the administration of the RAS receptor agonist and / or the PRR agonist.

43. The method of any one of claims 1-42, wherein the subject has need for continuous renal replacement therapy.

44. The method of any one of claims 1-43, wherein the administration of the RAS receptor agonist and / or the PRR agonist to the subject undergoing ultrafiltration is continued during subsequent ultrafiltration treatment.

45. The method of any one of claims 1-44, further comprising the administration to the subject a therapeutically effective amount of a drug that helps increase blood flow in the capillary bed, such as vasodilators such as nitroglycerin, hydralazine and AT4 receptor agonists that promote nitric oxide (NO) production such as angiotensin, calcium channel blockers such as amlodipine and nifedipine, ACE inhibitors such as lisinopil and enalapril, angiotensin II receptor blockers such as losartan and valsartan, phosphodiesterase inhibitors such as sildenafil and tadalafil, nitrates such as isosorbide dinitrate and isosorbide mononitrate, prostaglandins such as alprostadil and epoprostenol. pentoxifylline and alpha-blockers such as prazosin and doxazosin.

46. A method for maintaining cardiovascular and sympathetic nervous system homeostasis in a patient undergoing ultrafiltration, comprising administering to the patient a therapeutically effective amount of angiotensin II, wherein the angiotensin II modulates blood pressure and blood flow, thereby reducing the activation of the sympathetic nervous system and minimizing a catecholamine surge.

47. The method of claim 46, wherein the administration of angiotensin II prevents or reduces vasoconstriction in the microvasculature, thereby minimizing the risk of microvascular ischemia during or following ultrafiltration.

48. A method according to claim 46, wherein the administration of angiotensin II reduces the need for administration to the patient of other pharmacological agents, such as vasopressors or fluid boluses, that are commonly used to mitigate intradialytic hypotension and its associated catecholamine response.

49. The method of claim 46, wherein the administration of angiotensin II minimizes the risk of cardiac dysfunction, including cardiac stunning, by reducing the catecholamine-induced vasoconstriction and maintaining consistent myocardial perfusion during ultrafiltration.

50. The method of claim 46, wherein the administration of angiotensin II modulates vascular tone by acting on angiotensin II receptors to promote vasodilation in non- essential vascular beds, reducing systemic vascular resistance and the body’s need to release epinephrine and norepinephrine.

51. The method of claim 46, wherein the administration of angiotensin II helps maintain fluid-electrolyte balance during ultrafiltration, contributing to homeostatic stability and minimizing the activation of stress-related pathways, including the catecholamine response.

52. The method of claim 46. wherein the administration of angiotensin II prevents the excessive release of catecholamines, which can lead to peripheral vasoconstriction, thereby reducing the frequency and severity of skeletal muscle cramps during ultrafiltration.

53. A method for improving the clinical outcome of ultrafiltration by administering angiotensin II to a patient, wherein the angiotensin II ensures stable cardiac output, prevents fatigue, and minimizes brain and kidney injury by reducing the incidence of catecholamine surge and its effects on microvascular ischemia.

54. The method of claim 1, wherein the method maintains capillary perfusion in the patient and prevents ischemic injury to one or more organs selected from the group consisting of the heart, brain, kidney, liver, gut and skeletal muscle.

55. The method of claim 1, wherein the systemic microvascular ischemia is cerebral ischemia and the method prevents neurocognitive impairment.

56. The method of claim 55, wherein preventing neurocognitive impairment comprises preventing memory’ decline, executive dysfunction, or processing speed impairment in a subject undergoing chronic dialysis.

57. The method of claim 55, wherein the method reduces white matter injury detectable by near infrared spectroscopy (NIRS) or diffusion tensor MRI.

58. The method of claim 54, wherein the method reduces dialysis-associated fatigue or muscle cramping by preserving skeletal muscle perfusion.

59. The method of claim 54, wherein the method reduces kidney ischemia, thereby preventing acute-on-chronic kidney injury'.

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