Protective amino acid agents for peritoneal dialysis

Abstract

The present invention relates to a protective agent selected from the group consisting of L-glutamine, L-alanyl-L-glutamine, L-glutamyl-L-alanine, L-glutamyl-L-glycine, L-glycyl-L-glutamine, or a mixture thereof, and to a method for preparing the protective agent, the present invention relates to a protective agent for use in the prevention and / or treatment of diseases associated with end-stage nephropathy (ESKD) mediated by liver dysfunction induced by peritoneal dialysis treatment, specifically for the prevention and / or treatment during peritoneal dialysis treatment: (A) liver diseases induced by said peritoneal dialysis treatment and / or (B) diseases associated with ESKD mediated by liver dysfunction induced by said peritoneal dialysis treatment, wherein said protective agent is administered by intraperitoneal administration.

Description

Technical Field

[0001] This invention relates to a protective agent for peritoneal dialysis treatment, its specific therapeutic uses, and treatment methods using said protective agent. Background Technology

[0002] Chronic kidney disease (CKD) and renal failure lead to uremic toxin retention and fluid excess, most notably in patients with end-stage renal disease (ESKD) (1). ESKD is also strongly associated with an increased risk of systemic inflammation, including metabolic inflammation, which is defined as a chronic low-grade inflammatory state induced by metabolic alterations. Furthermore, ESKD is associated with atherosclerosis and cardiovascular disease (CVD) (2).

[0003] Peritoneal dialysis (PD) is a home-based renal replacement therapy for ESKD with similar survival rates compared to hemodialysis (HD) (3). Peritoneal dialysate (PDF) is injected into the peritoneal cavity using a sterile procedure and removed after several hours. PD is primarily driven by PDF pressure gradients based on hypertonic glucose or colloids, reducing uremic toxins and fluid excess through small solute diffusion and ultrafiltration of water across the peritoneum. While PD provides a life-saving renal replacement, it also introduces typical surgery-related complications, increasing the incidence of uremia in ESKD (3). Prolonged exposure to PDF leads to a high load of intraperitoneal glucose and its degradation products (GDP), which is associated with inflammation and vascular changes (4, 5) and may enhance metabolic and cardiovascular risk profiles (6).

[0004] Most commercially available PDFs contain glucose monohydrate as their primary permeation agent. Alternatively, PDFs may contain glucose polymers (i.e., icodextrin) or colloidal permeation substances (such as amino acids or peptides).

[0005] Some clinical and experimental observations suggest that PDF is cytotoxic and is associated with a technical failure risk of up to 30% in long-term PD treatment (7).

[0006] WO2008 / 106702A1 provides a glucose-based peritoneal fluid containing a protectant in the form of L-glutamine and a dipeptide capable of releasing L-glutamine, said dipeptide being L-glutyl-L-glycine, L-glycine-L-glutamine, L-glutyl-L-alanine, or L-alanyl-L-glutamine, or a mixture of two or more said dipeptides, wherein said dipeptide is present at a concentration of 2 mM to 25 mM in the dialysate.

[0007] According to this patent application, these dipeptides, particularly L-alanyl-L-glutamine (hereinafter referred to as alanyl-glutamine or "Ala / Gln"), have been found to help prevent the failure of the technology.

[0008] The common idea behind these protectants is their ability to release L-glutamine. Therefore, although alanyl-glutamine is mentioned primarily below, it can be expected that the reported effects will also be achieved when other protectants in the above group are used.

[0009] Some publications have further investigated the role of Ala / Gln in glucose-based PDFs (8-26).

[0010] The liver is increasingly recognized as a central hub connecting metabolism and CVD (27). To enable the liver to tolerate exposure to gut-derived microbes and dietary molecules, metabolic activity and associated inflammatory processes are tightly controlled. Stimulation occurs when there is a need to clear hepatotropic pathogens or toxic products of metabolic activity (28). Several studies have shown an epidemiological association between CKD and chronic liver disease, with recent research focusing on metabolic stress that leads to renal-hepatic crosstalk (29, 30).

[0011] In CKD, the liver can act as either a victim, developing specific symptoms such as fatty liver disease (MAFLD) associated with metabolic (functional impairment), or a perpetrator, mediating an environment that contributes to CKD-related CVD. The liver's central role in detecting and responding to extrahepatic and intrahepatic signals is achieved through an acute-phase response, which amplifies inflammatory stimuli by several orders of magnitude. Hepatocytes produce acute-phase proteins (such as complement proteins and C-reactive protein [CRP]), which then promote systemic inflammation through direct effector functions (27, 28).

[0012] Although these pathological mechanisms are very common in ESKD patients receiving PD treatment, the inventors of this invention are unaware of any mechanistic studies that link PD to liver disease or elucidate the role of PD-induced liver dysfunction in PD-related conditions such as CVD.

[0013] Clinical reports linking PD to the liver are few and inconclusive. Historical reports have shown the presence of subcapsular hepatic steatosis in PD patients and its occurrence associated with concurrent use of intraperitoneal insulin and glucosyl PDF, which is associated with high rates of peritoneal metastasis and high body weight (31, 32). A small cross-sectional study reported that the high prevalence of chronic liver disease in PD patients was associated with a high risk of atherosclerosis, and therefore with CVD (33). PD patients have been reported to have higher liver enzymes compared to HD patients in some studies (34), but not in others (35). Liberato et al. discussed the possibility that the elevated levels of gamma-glutamyl transferase (GGT) observed in two dialysis groups could be associated with malnutrition-inflammation-atherosclerosis syndrome (34), thus being closely related to CVD. Therefore, it remains unclear whether PD has a specific effect on the liver in clinical PD, and the role of PD-induced liver dysfunction in the inflammatory response.

[0014] Further background information can be found in Ferrantelli Evelina et al., Kidney International 89(3) 2016, 625-635 and Mikolasevic et al., Medical Hypotheses 82(2) 2013, 205-208. Summary of the Invention

[0015] The purpose of this invention is to provide improvements in the side effects associated with PD.

[0016] This objective is achieved through the subject matter of claim 1.

[0017] Other preferred embodiments of the invention are disclosed in the dependent claims. Attached Figure Description

[0018] Figure 1 Peritoneal dialysis-induced liver inflammation. Control mice with and without PD, and uremia mice.

[0019] Inflammation score and nonalcoholic fatty liver disease (NAFLD) activity score (NAS). P-value calculated by the Mann-Whitney U test, without multiplicity correction.

[0020] a. Changes in healthy animals

[0021] b. Changes in animal models of uremia

[0022] Figure 2Effect of alanyl-glutamine supplementation to PDF on PD-induced liver inflammation. Control mice, PD-treated uremic mice, and PD- and AlaGln-supplemented uremic mice were included. P-values ​​were calculated using the Mann-Whitney U test, without multiplicity correction.

[0023] a. Inflammation score and NAFLD activity score (NAS);

[0024] b. Percentage of the area of ​​Oil Red O stained tissue (=fatty degeneration) on liver sections

[0025] c. Percentage of Sirius red stained tissue (=fibrosis) on liver sections.

[0026] Figure 3 Effects of alanyl-glutamine administration on specific biomarkers associated with cardiovascular disease. Control mice, uremic mice treated with PD, and uremic mice treated with PD and AlaGln supplementation.

[0027] The abundance of APOH, CFB, and CRP in liver tissue was assessed using mass spectrometry proteomics analysis.

[0028] Figure 4 The correlation between changes in various liver parameters induced by alanyl-glutamine treatment in patients with long-term PD, and their correlation with changes in systemic inflammatory parameters. A secondary analysis of a prospective, multicenter phase II trial on the effects of alanyl-glutamine on clinical parameters of liver injury in patients with long-term PD is added to the PDF.

[0029] a) Spearman's rank correlation: Black blocks indicate positive correlation (p-value < 0.1, without multiplicity correction). White blocks indicate non-significant positive correlation (p-value ≥ 0.1).

[0030] b. Spearman rank correlation between changes in plasma interleukin-6 and changes in GGT levels (rho = 0.35, p = 0.03, without multiplicity correction). Detailed Implementation

[0031] The inventors have for the first time analyzed the effects of PD itself on the livers of uremia and non-uremia animals, and surprisingly found that PD, especially PD utilizing glucose-based PDF, itself induces liver disease, thereby increasing the likelihood of diseases mediated by liver dysfunction.

[0032] In the inventors' research, uremic and non-uremic animals receiving PD were permitted for mechanistic studies to elucidate the specific effects of PD on hepatic molecular responses in a rigorously controlled experimental model of CKD. Experimental data indicated that PD treatment was associated with increased liver inflammation and acute-phase reactions as a novel treatment-specific adverse event, potentially diminishing its beneficial effects in reducing uremic toxemia and hyperhydration in ESKD patients. Furthermore, the experimental setup of PD in non-uremic animals in the inventors' research allowed for unique insights into the pathological mechanisms associated with specific PD surgery, insights that would otherwise be unattainable. Interestingly, the results of these experiments clearly confirmed the differential expression of liver proteins associated with acute-phase hepatic response signaling without CKD as a confounding factor.

[0033] These data indeed demonstrate a direct causal role for specific PD factors in inducing liver inflammation and acute-phase response signaling, as well as subsequent systemic inflammation (particularly metabolic inflammation) and CVD in patients with PD. Excessive energy and nutrients directly transferred to the liver via portal vein flow through the peritoneum induced by PDF may lead to metabolic stress, triggering altered metabolic inflammation and immune responses, thereby promoting liver disease and CVD.

[0034] In summary, the inventors have found direct evidence of liver symptoms and dysfunction induced by PD. By applying the established long-term PD exposure model to uremic and non-uremic mice, their histological and proteomic findings directly linked chronic intraperitoneal PDF exposure, via the portal peritoneum-liver axis, to liver inflammation and liver-mediated systemic inflammation (particularly metabolic inflammation), rather than to CKD.

[0035] The inventors have discovered that using the protective agent of claim 1, particularly alanyl-glutamine, during intraperitoneal administration in peritoneal dialysis treatment can mitigate the negative effects of PDF on the liver.

[0036] The inventors investigated the potential effects of alanyl-glutamine supplementation on the liver in a long-term rat model of liver disease (PD). This treatment significantly reduced PD-induced liver symptoms and liver-mediated metabolic inflammation. Histologically, the improvement in NAFLD activity score (NAS), primarily due to reduced inflammatory infiltration, provides evidence of alanyl-glutamine-mediated reduction in PD-induced morphological liver pathology. This morphological improvement correlates with corresponding molecular responses observed in the rat liver proteome.

[0037] Alanyl-glutamine has been shown to reduce liver reperfusion injury in rat models, protect mice from LPS-induced acute liver injury, and significantly alleviate steatohepatitis and fibrosis in a rat NAFLD model (36-38).

[0038] However, to date, no one has suggested that the use of alanyl-glutamine directly affects PD-induced liver disease and / or further liver-related negative consequences of PD.

[0039] Therefore, in a first aspect, the present invention provides a protective agent selected from the group consisting of L-glutamine, L-alanyl-L-glutamine, L-glutyl-L-alanine, L-glutyl-L-glycine, L-glycyl-L-glutamine, or mixtures thereof, specifically for the prevention and / or treatment of the following diseases during peritoneal dialysis:

[0040] (A) Liver disease induced by the peritoneal dialysis treatment and / or

[0041] (B) Liver dysfunction mediated by the peritoneal dialysis treatment described above that is associated with end-stage renal disease (ESKD).

[0042] The protective agent is administered via intraperitoneal administration.

[0043] Another aspect of the invention relates to the preventive and / or therapeutic use of the protective agent during peritoneal dialysis treatment of said disease (A) and / or (B).

[0044] Another aspect of the invention relates to the use of the protective agent in the preparation of medicaments for the treatment or prevention of said diseases (A) and / or (B) during peritoneal dialysis treatment.

[0045] Another aspect of the invention relates to a method of administering the protective agent to a subject in need via intraperitoneal administration during peritoneal dialysis to prevent and / or treat the disease (A) and / or (B).

[0046] The following discussion may refer to any of the above aspects, with necessary modifications.

[0047] In a preferred embodiment of the invention, the liver disease (A) induced by peritoneal dialysis treatment is a chronic liver disease, particularly non-infectious liver inflammation.

[0048] Non-infectious liver inflammation includes diseases such as non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and metabolic (functional)-associated fatty liver disease (MAFLD).

[0049] In patients with ESKD, the pathophysiological mechanisms linking PD to the liver cannot be separated from the effects of renal-hepatic crosstalk in CKD and its chronic low-grade inflammatory and metabolic factors (e.g., associated with atherosclerotic dyslipidemia and glycemic abnormalities (30)). CKD and fatty liver disease share many risk factors (e.g., obesity, hypertension, insulin resistance, type 2 diabetes, atherogenic dyslipidemia), resulting in a prevalence of CKD of approximately 20–55% in the non-alcoholic fatty liver disease (NAFLD) population, significantly higher than the 5–35% in the non-NAFLD population (39). Furthermore, several studies have shown an association between CKD and NAFLD, describing a broader phenotype of metabolic (functional impairment)-associated fatty liver disease (MAFLD), further emphasizing the pathogenic role of metabolic dysfunction, and the increased risk of CVD from CKD, MAFLD, and their common and non-common risk factors (29, 30, 40–43). In a population-based study, the positive correlation between the fatty liver index (a marker of hepatic steatosis) and the incidence of CKD was entirely mediated by the combined effects of the most important cardiometabolic risk factors (44). Liver pathological markers were significantly associated with serum CRP, ALT, AST, and lipid markers (i.e., cholesterol, LDL, triglycerides) as well as CVD in dialysis patients (45). Furthermore, liver function parameters were positively correlated with poor prognosis, CVD, and all-cause morbidity in patients with ESKD and PD (46).

[0050] To date, there are no reported data on the effects of alanyl-glutamine on liver injury and liver-mediated systemic metabolic inflammation (which may cause CVD) in patients with PD.

[0051] Therefore, in addition to the experiments in animal models described above, the inventors also conducted a secondary analysis of the results from a recent clinical PD trial (in human patients, 8) to validate their experimental findings.

[0052] As a result of this new analysis, the inventors were able to determine that the addition of alanine-glutamine to the PDF significantly reduced clinical parameters of liver injury, with statistical significance for LDH and liver-specific ALT.

[0053] In the aforementioned experiment (8), it was also reported that the addition of alanine-glutamine to PDF could reduce systemic inflammation, which was reflected in the decreasing trend of biomarkers such as hs-CRP and IL-6, and reached statistical significance for IL-8 (8, Table 3).

[0054] The inventors’ new secondary analysis now also reveals a significant association between changes in systemic inflammatory markers (interleukin-6) and changes in liver enzymes (GGT) and clinical markers of cell lysis (AST, LDH).

[0055] These findings also confirm the inventors’ experimental findings in a mouse model that alanyl-glutamine has therapeutic effects on regulated cell death (e.g., necrotizing apoptosis signaling) and systemic inflammation, particularly metabolic inflammation, indicating that alanyl-glutamine works on the liver of PD patients, which acts as both a victim (sentinel) and a perpetrator (mediator).

[0056] In summary, the findings of the human clinical trial and new secondary data analysis indicate that, in the experimental system, intraperitoneal treatment with alanine-glutamine not only alleviated liver inflammatory damage and liver-mediated systemic inflammation induced by PD, especially metabolic inflammation, but also led to a reduction in clinical parameters related to liver damage and systemic inflammation in patients with long-term PD.

[0057] In another embodiment of the invention, the ESKD-related disease (B) mediated by liver dysfunction is a cardiovascular disease, particularly atherosclerotic cardiovascular disease, including cardiovascular diseases caused by inflammation and cardiovascular diseases caused by metabolic inflammation.

[0058] As mentioned above, the liver is increasingly recognized as a central hub connecting metabolism and CVD.

[0059] As discussed above, in the experimental system, intraperitoneal treatment with alanine-glutamine not only alleviated liver inflammatory damage and liver-mediated systemic inflammation induced by PD, especially metabolic inflammation, but also led to a reduction in clinically relevant parameters of liver damage and systemic inflammation in patients with long-term PD.

[0060] The inventors' discovery of a new reduction in the side effects of PD by adding alanyl-glutamine to the PDF provides a new targeted therapy option for PD patients to improve systemic inflammation, particularly metabolic inflammation, thereby improving CVD prognosis.

[0061] This new treatment option could provide a suitable alternative to the administration of anti-inflammatory biologics, such as IL-6-specific antibodies.

[0062] In one embodiment of the invention, administration of the protective agent begins at the start of the peritoneal dialysis treatment.

[0063] In another embodiment of the invention, administration of the protective agent begins some time after the start of the peritoneal dialysis treatment.

[0064] In this implementation, medication can be initiated once markers of liver disease or liver-mediated systemic inflammation, particularly metabolic inflammation, associated with peritoneal dialysis treatment are detected. These markers can be biomarkers, such as laboratory markers and / or imaging findings.

[0065] As indicators of liver disease, serum markers of hepatobiliary damage (e.g., AST, ALT, GGT, ALP, bilirubin) and / or imaging findings indicating liver damage and / or hepatitis and / or steatosis / deposition and / or fibrosis (e.g., MRI, CT, PET, liver elastography, ultrasound) can be observed.

[0066] As indicators of inflammation / metabolic inflammation, serum markers (e.g., CRP, hs-CRP, IL-6, IL-8, albumin, fibrinogen, SAA) and / or erythrocyte sedimentation rate and / or imaging findings (e.g., PET) can still be observed.

[0067] As indicators of cardiovascular disease, especially cardiovascular disease caused by inflammation / metabolic inflammation, biomarkers (e.g., CRP, hs-CRP, IL-6, IL-8, fibrinogen, SAA) and / or imaging findings (e.g., angiography, MRI, CT, PET, ultrasound) can still be observed.

[0068] According to the present invention, the protective agent is administered intraperitoneally to reach those sites in the body directly affected by PD treatment.

[0069] Intraperitoneal administration can be performed by intraperitoneal injection or infusion of a protectant in a suitable drug carrier known to those skilled in the art.

[0070] Administration can be done intermittently or continuously.

[0071] In a particularly preferred embodiment, the protective agent is administered as a component of the peritoneal dialysis fluid (PDF).

[0072] The PDF containing the protective agent can preferably be exactly the same as the PDF applied to the patient for PD treatment.

[0073] In this case, the body that has already undergone PD treatment does not need to receive another different treatment plan.

[0074] In this implementation, a PDF containing a protective agent (as the only PDF) can be administered from the start of the PD treatment.

[0075] Alternatively, if treatment is initiated with a different peritoneal dialysis fluid, the other PDF can be completely replaced with a fluid containing a protective agent, especially after indicators of liver disease or liver-mediated systemic inflammation, particularly metabolic inflammation, are detected.

[0076] Preferably, during PD treatment, the liquid containing the protective agent is administered as the sole PDF. This means that the patient is treated only with the PDF containing the protective agent.

[0077] In another embodiment, the fluid can be administered in combination with another peritoneal dialysis fluid. This other peritoneal dialysis fluid can be selected from any available PDF compatible with a PDF containing a protective agent.

[0078] In another embodiment of the invention, the PDF containing the protective agent is based on glucose as a permeabilizing agent.

[0079] Preferably, the protective agent used according to the invention or in the method of the invention is L-alanyl-L-glutamine, optionally mixed with one or more other protective agents.

[0080] Example

[0081] Examples 1 and 2—Rat Experimental Models

[0082] method

[0083] The inventors conducted mouse PD exposure experiments similar to long-term PD in healthy and uremic mice:

[0084] The experiment consisted of n=34 animals, divided into six different groups.

[0085] The animals were divided into the following groups:

[0086] 1) Healthy control animals (“control”)

[0087] 2) Healthy animals receiving PD treatment (via indwelling catheter) (“PD”)

[0088] 3) Healthy animals receiving PD treatment supplemented with alanyl-glutamine (via indwelling catheter) (“PD+AG”)

[0089] 4) Uremic animals (“uremia”)

[0090] 5) Uremic animals receiving PD treatment (via indwelling catheter) (“Uremic PD”)

[0091] 6) Uremic animals receiving PD therapy supplemented with alanyl-glutamine (via indwelling catheter) (“Uremic PD+AG”)

[0092] All animals in the uremia group (groups 4, 5, and 6) underwent left 2 / 3 nephrectomy on day 0 of the study and right nephrectomy on day 7 of the study, thereby inducing chronic kidney disease.

[0093] All animals that received PD treatment (groups 2, 3, 5, and 6) had indwelling catheters implanted on day 7 of the study.

[0094] Starting on day 14, animals in groups 2, 3, 5, and 6 received daily injections of PDF (Dianeal PD4 3.86% [Baxter, Deerfield, IL, USA]) via their indwelling catheters for six weeks, thereby inducing long-term PDF exposure.

[0095] For animals in groups 3 and 6, daily PDF injections supplemented with alanyl-glutamine (8 mM) were administered during the six-week period.

[0096] Histological analysis was performed on the livers of the animals at the time of sacrifice (day 56 of the study).

[0097] As described above (47), hematoxylin and eosin (H&E) stained liver tissue was assessed using the NAFLD activity score (NAS) on a facial region image of each mouse.

[0098] Fatty liver was assessed by semi-quantitative measurement of Oil Red O stained liver tissue using one facial region image per mouse.

[0099] Liver fibrosis was assessed by semi-quantitative measurement of Sirius red-stained liver tissue using one facial region image per mouse.

[0100] Example 1—Regardless of uremia status, PD induces liver damage—Alanyl-glutamine weakens this effect of PD.

[0101] At the end of the experiment, H&E-stained liver histology showed a significant increase in the number of infiltrating inflammatory immune cells, especially near the interlobular veins (peritoneal flow) of the portal venous system, while the area of ​​hepatocyte ballooning degeneration increased in animals treated with PD.

[0102] like Figure 1 As shown, these findings manifested as a significant increase in NAFLD activity scores (NAS) in mice treated with PD.

[0103] Figure 1 a shows these changes in healthy animals, while Figure 1 b shows these changes in the animal model of uremia. In both groups, mice receiving PD showed a significant increase in NAFLD activity score (NAS) compared to mice that did not receive PD (p<0.05).

[0104] Therefore, this effect of PD was observed in both healthy and uremic animals, that is, regardless of the uremic state. These increases in NAS were primarily caused by higher amounts of inflammatory infiltrates.

[0105] On the other hand, the addition of alanyl-glutamine to the PDF significantly reduced the number of inflammatory immune cell infiltrates, decreased the area of ​​hepatocyte ballooning degeneration in H&E liver sections, and significantly reduced NAS semi-quantitatively expressed in uremic mice (p<0.05). Similarly, this was mainly due to the presence of inflammatory infiltrates. Figure 2 a). Furthermore, by adding alanyl-glutamine to the PDF, PD-induced hepatic steatosis (e.g.) could be observed. Figure 2 b) shows the percentage of area of ​​tissue stained with Oil Red O (as shown in b) and fibrosis (e.g. Figure 2 The improvement trend is shown by the percentage of Sirius red stained tissue area (as indicated by c).

[0106] Example 2—PD treatment induces liver inflammation and acute phase reactions; similarly, alanyl-glutamine attenuates this effect.

[0107] To investigate the effects of PD-induced or related hepatic molecular inflammatory responses and to discover potential new therapeutic interventions, mass spectrometry proteomics analysis was performed on the livers of all animals in the rat experiment in Example 1.

[0108] The inventors used Ingenuity Pathway Analysis (EMEA Qiagen, Aarhus, Denmark) to extract all identified proteins that are either part of acute-phase response signaling pathways or pathways associated with liver inflammation. In the subset of proteins identified by PLS-DA (Partial Least Squares Discriminant Analysis) as the most significant differentially expressed in the livers of animals that underwent and did not undergo PD, 57 proteins were significantly aberrantly regulated by PD compared to control animals (p<0.05, variance-stable linear model using empirical Bayesian contraction).

[0109] Supplementation with alanyl-glutamine in the PDF significantly altered the abundance of 11 acute-phase response and inflammation-related proteins in the liver of uremic animals treated with PD (p<0.05, using a variance-stable linear model with empirical Bayesian contraction). These 11 proteins are part of pathways involving acute-phase response signaling (e.g., CFB, APOH, and RELA), glucocorticoid receptor signaling (e.g., HSPA5, NCOR1, NDUFA4, NDUFB3, SDHB, RELA, and IRF3), and necroptosis signaling (e.g., TIMM13, PPID, and IRF3).

[0110] Figure 3 The effect of this on three selected biomarkers (APOH, CFB, and CRP) is illustrated graphically. These biomarkers are known to be clinically relevant to cardiovascular risk.

[0111] Therefore, the inventors here demonstrate the well-described effects of PD on liver inflammation and liver-mediated systemic inflammation, particularly metabolic inflammation, and the improvement of liver protein levels by supplementing PDF with alanyl-glutamine. The effects of PDF supplementation on PD-induced liver inflammation and liver-mediated systemic inflammation, particularly metabolic inflammation, are primarily achieved by modulating proteins in the acute phase response signaling pathway, the glucocorticoid receptor signaling pathway (regulating NFκB and its respective downstream effects), and the necroptosis signaling pathway.

[0112] Example 3—Alanyl-Glutamine Supplementation in PDF Improves Liver Function (Impairment) in Human PD Patients

[0113] To further investigate the effects of alanyl-glutamine supplementation in PDF on liver (dysfunction) induced by human PD, the inventors conducted a secondary analysis of a prospective, multicenter, double-blind, controlled, randomized, two-phase, two-treatment, crossover, phase II, proof-of-concept study in PDF of patients with long-term PD, including eight Austrian centers.

[0114] To this end, the inventors included liver tests (GOT / AST, GPT / ALT, GGT, LDH) obtained as safety data in all patients in the complete analysis set. Since the protocol analysis excluded patients with interfering correlations only with local peritoneal effects, this resulted in n=41 patients with long-term PD being randomly assigned to either the placebo group I (arm) or the alanine-glutamine group I in this crossover study for secondary analysis purposes.

[0115] Vychytil et al. have previously described this study cohort and its baseline characteristics (8).

[0116] Supplementation with alanyl-glutamine in the PDF significantly reduced clinical markers of liver injury. These effects of alanyl-glutamine in human trials in patients with long-term PD are highly consistent with the protein-level effects of alanyl-glutamine on regulating cell death (e.g., necroptotic signaling) described in mouse experiments in Example 2.

[0117] Table 1 below shows the effect of alanyl-glutamine supplementation in the PDF on functional markers of liver function (disorder).

[0118]

[0119]

[0120] * Log10 transformation was performed due to skewness.

[0121] Furthermore, changes induced by alanyl-glutamine supplementation in the PDF were observed to be positively correlated with different clinical diagnostic markers of hepatobiliary injury. This was observed in... Figure 4 As shown in a. Because each marker exhibits a different pattern of cell damage within the hepatobiliary system, different significance levels can be observed for each correlation pair.

[0122] Figure 4 b shows that changes induced by alanyl-glutamine supplementation in the PDF were positively correlated with one of the clinical diagnostic markers of hepatobiliary injury (GGT) and inflammation (IL-6). As mentioned above, systemic administration of anti-inflammatory biologics (such as IL-6-specific antibodies) has been developed as a therapeutic option for treating metabolic inflammation and reducing CVD risk. Therefore, Figure 4 The observed reduction in clinical diagnostic markers of hepatobiliary injury induced by alanyl-glutamine supplementation in PDFs (Table 1) was analyzed. Figure 4 a) A reduction in clinically diagnostic markers of observed inflammation, particularly / including / and metabolic inflammation ( Figure 4 b) This link. This validated the mechanism of action of alanyl-glutamine in a mouse PD model observed in Examples 1 and 2 in a human clinical randomized placebo-controlled phase II trial.

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Claims

1. A protective agent selected from the group consisting of L-glutamine, L-alanyl-L-glutamine, L-glutyl-L-alanine, L-glutyl-L-glycine, L-glycyl-L-glutamine, or mixtures thereof, specifically for the prevention and / or treatment of peritoneal dialysis: (A) Liver disease induced by the peritoneal dialysis treatment and / or (B) Diseases related to end-stage renal disease, i.e., ESKD, mediated by liver dysfunction induced by the aforementioned peritoneal dialysis treatment. The protective agent is administered via intraperitoneal administration.

2. The protective agent according to claim 1, wherein the liver disease (A) caused by the peritoneal dialysis treatment is a chronic liver disease, particularly non-infectious liver inflammation.

3. The protective agent according to claim 2, wherein the non-infectious liver inflammation includes non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and metabolic (functional)-associated fatty liver disease (MAFLD).

4. The protective agent according to any one of the preceding claims, wherein the ESKD-related disease (B) mediated by liver dysfunction is a cardiovascular disease, particularly atherosclerotic cardiovascular disease, including inflammation-driven cardiovascular disease and metabolic inflammation-driven cardiovascular disease.

5. The protective agent according to any one of the preceding claims, wherein administration of the protective agent begins at the start of the peritoneal dialysis treatment.

6. The protective agent according to any one of claims 1 to 4, wherein administration of the protective agent begins some time after the start of the peritoneal dialysis treatment.

7. The protective agent according to claim 6, wherein administration of the protective agent is initiated once an indicator of liver disease or liver-mediated systemic inflammation, particularly metabolic inflammation or cardiovascular disease, is detected.

8. The protective agent according to claim 7, wherein the indicator is selected from the group consisting of biomarkers, such as laboratory markers and / or imaging results.

9. The protective agent according to any one of the preceding claims, wherein the protective agent is administered as a component of peritoneal dialysis fluid (PDF).

10. The protective agent according to claim 9, wherein the peritoneal dialysis fluid is administered as the sole peritoneal dialysis fluid during peritoneal dialysis treatment.

11. The protective agent according to claim 9, wherein the peritoneal dialysis fluid is administered in combination with another peritoneal dialysis fluid.

12. The protective agent according to any one of claims 9 to 11, wherein the peritoneal dialysis fluid is based on glucose as an osmotic agent.

13. The protective agent according to any one of the preceding claims, wherein the protective agent is L-alanyl-L-glutamine, optionally mixed with one or more other protective agents.

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