Use of quinolinic acid in the preparation of drugs for preventing and treating acute kidney injury

Abstract

This invention discloses the application of quinolinic acid in the preparation of drugs for the prevention and treatment of acute kidney injury (AKI). AKI refers to acute kidney injury induced by renal ischemia-reperfusion. The drug is an oral formulation used for prophylactic administration in high-risk individuals undergoing iatrogenic procedures at potential AKI risk, and for pretreatment of ischemic conditions in transplanted kidneys. Experiments have shown that administration of quinolinic acid significantly reduces serum urea nitrogen levels in AKI mice, alleviates renal tissue morphological damage in AKI mice, and reduces the expression level of the renal tubular injury factor NGAL protein in AKI mice, demonstrating significant clinical value in the prevention and treatment of AKI.

Description

Technical Field

[0001] This invention belongs to the field of medicine, specifically relating to the application of quinolinic acid in the preparation of drugs for the prevention and treatment of acute kidney injury. Background Technology

[0002] Acute kidney injury (AKI), a critical clinical condition characterized by a rapid decline in renal filtration function, has become a serious global public health challenge. Its incidence is rising annually, with an incidence of approximately 7-11.6% among hospitalized patients in my country, exceeding 50% in ICU patients. The severity of AKI directly impacts mortality and prognosis: the mortality rate for dialysis-dependent patients reaches 50%; over 30% of non-dialysis patients will progress to stage 4 chronic kidney disease (CKD) or end-stage renal disease (ESRD); even with short-term renal function recovery, the long-term risk of progression to CKD and ESRD increases dramatically by 2.61 times and 4.81 times, respectively. Data from 2013 shows that there were approximately 1.4 million hospitalized AKI patients in my country, consuming 10% of the country's total medical resources (approximately US$13 billion), placing a heavy economic burden on the nation. Unfortunately, despite significant progress in pathological mechanism research and dialysis technology, there are currently no effective interventions to alleviate primary kidney injury or promote kidney repair, resulting in a bottleneck in clinical prevention and treatment.

[0003] Nicotinamide adenine dinucleotide (NAD) + Initially discovered to participate in glycolysis as a hydrogen carrier, subsequent studies further revealed that NAD+... + It also acts as a key cofactor in reactions catalyzed by various enzymes, including Sirtuins, PARPs, and CD157 / CD38. Based on these functions, NAD... + NAD+ plays a crucial role in the occurrence and development of acute kidney injury by deeply regulating biological processes such as mitochondrial function, DNA repair, oxidative stress, and inflammation. NAD+ in mammals... + NAD+ synthesis primarily relies on two pathways: the salvage synthesis pathway and the de novo synthesis pathway. The activity of both pathways affects NAD+ levels in the kidneys. + The de novo synthesis pathway, which uses tryptophan as a starting substrate, generates quinolinic acid (QA) through a cascade of enzymes. This pathway is the main source of quinolinic acid in the body. Quinolinic acid is ultimately converted into NAD+. +Quinolinic acid plays an indispensable role in energy metabolism, DNA damage repair, cell senescence, and apoptosis regulation. Furthermore, studies have shown that quinolinic acid itself has broad biological functions at physiological concentrations: it not only participates in normal physiological processes such as neurotransmitter regulation and synaptic plasticity maintenance, but also plays an important role in key aspects such as immune regulation and anti-oxidative stress. However, there are currently no reports on quinolinic acid supplementation promoting kidney repair and improving acute kidney injury. Summary of the Invention

[0004] To address the lack of effective treatments for acute kidney injury (AKI), this invention provides the application of quinolinic acid in the preparation of drugs for the prevention and treatment of AKI. This invention demonstrates through animal experiments the effectiveness of quinolinic acid as an oral medication in the prevention and treatment of AKI. Oral supplementation with quinolinic acid, via NAD+... + Synthesizing NAD through de novo synthesis pathway + This can reduce renal tubular damage and prevent and improve acute kidney injury.

[0005] This invention provides the application of quinolinic acid in the preparation of drugs for the prevention and treatment of acute kidney injury using the following technical solution: This invention provides the application of quinolinic acid in the preparation of drugs for the prevention and treatment of acute kidney injury.

[0006] Preferably, the acute kidney injury is acute kidney injury induced by renal ischemia-reperfusion.

[0007] Preferably, the drug is an oral preparation.

[0008] Preferably, the drug is used for prophylactic administration in high-risk individuals facing potential acute kidney injury during iatrogenic procedures.

[0009] Preferably, the drug is used for the pretreatment of ischemic conditions in transplanted kidneys.

[0010] The present invention conducted the following animal model experiments: 1. In vivo experiments on the association between decreased quinolinic acid levels and aggravation of acute kidney injury in mice. Eight-week-old female and male mice were used to surgically establish an acute kidney injury model induced by ischemia-reperfusion injury (IRI). Blood was collected 48 hours post-surgery to assess renal function by measuring blood urea nitrogen (BUN) levels. Both kidneys were harvested; a portion was fixed in paraffin, sectioned, and examined under a microscope for pathological changes to assess morphological damage, while the other portion was used for molecular biology experiments to quantify the degree of renal cell damage and to detect renal quinolinic acid (quinolinic acid) levels by mass spectrometry. Results showed that, compared to male mice, female mice exhibited less significant increases in BUN after IRI, reduced acute tubular necrosis under light microscopy, and lower expression of the tubular injury factor NGAL, while renal quinolinic acid levels were significantly elevated. This suggests that decreased quinolinic acid levels in male mice are associated with more severe acute kidney injury.

[0011] 2. In vivo experiment of quinolinic acid in treating acute kidney injury in mice Eight-week-old male mice were used to surgically establish an ischemia-reperfusion-induced acute kidney injury model. Forty-eight hours prior to ischemia-reperfusion, mice were administered quinolinic acid (purchased from Sigma-Aldrich, USA, at a dose of 25 mg / kg / day) via gavage. 25 mg of quinolinic acid was dissolved in 10 ml of normal saline, and 0.2 ml of the solution was administered to each 20 g mouse via gavage once daily. A final dose of quinolinic acid was given four hours before sacrifice, for a total of five administrations. The control group received an equal volume of normal saline (NS) via gavage for five consecutive days. Forty-eight hours after modeling, serum was collected to measure blood urea nitrogen levels to assess renal function. Both kidneys were harvested; one portion was fixed in paraffin, sectioned, and examined under a microscope for pathological changes to assess renal morphological damage, while the other portion was used for molecular biology experiments to quantify the degree of renal cell damage. The results showed that administration of quinolinic acid reduced the increase in blood urea nitrogen, renal tubular necrosis under light microscopy, and increased expression of kidney injury factors in male rats induced by ischemia-reperfusion injury, suggesting that quinolinic acid supplementation has a therapeutic effect on ischemia-reperfusion-induced acute kidney injury.

[0012] The above results confirm that low levels of quinolinic acid in the kidneys of mice are highly correlated with more severe ischemia-reperfusion-induced acute kidney injury, and that quinolinic acid supplementation significantly improves acute kidney injury in mice, making it suitable for the development of drugs to prevent and treat acute kidney injury.

[0013] Compared with the prior art, the application of quinolinic acid provided by the present invention in the preparation of drugs for the prevention and treatment of acute kidney injury has the following beneficial effects: 1. Oral administration significantly improves patient compliance and treatment accessibility: This invention is the first to verify the efficacy and safety of quinolinic acid administered orally in the treatment of acute kidney injury. Oral administration requires no medical assistance and can be completed by the patient independently, avoiding the physical and psychological burden of intravenous medication. It is particularly suitable for treatment cycles requiring multiple consecutive days of administration. This characteristic has irreplaceable clinical value for early-stage AKI patients who have not yet met the criteria for hospitalization, as well as patients who require consolidation therapy after discharge.

[0014] 2. This invention provides a novel etiological intervention strategy that differs from traditional symptomatic and supportive treatments: Currently, in clinical practice, apart from renal replacement therapy (dialysis), there is a lack of specific drugs that effectively improve renal function in patients with acute kidney injury. This invention, by verifying the direct protective effect of quinolinic acid on renal tubular cells, provides an intervention method to alleviate acute kidney injury at the etiological level, solving the problem of "treating the symptoms but not the root cause" in existing technologies.

[0015] 3. This invention provides a "prevention before disease" intervention strategy to establish a kidney protective barrier for high-risk groups facing potential iatrogenic damage: Clinically, there are many patients undergoing high-risk procedures for kidney damage, such as major cardiac surgery, liver transplantation, and nephrotoxic chemotherapy infusions. Existing intervention strategies often only initiate treatment after acute kidney injury occurs, by which time irreversible damage to the renal tubular epithelial cells has already occurred. This invention proposes prophylactic oral supplementation of quinolinic acid before kidney injury occurs (such as before surgery), activating the self-protective mechanism of renal tubular epithelial cells at the "first moment" of ischemic exposure, thus blocking damage at the initial stage. Attached Figure Description

[0016] Figure 1 The changes in serum urea nitrogen levels in 8-week-old C57BL / 6J female and male mice 48 hours after ischemia-reperfusion-induced acute kidney injury in Example 1 of this invention; Figure 2 The image shows the H&E staining of kidney tissue from 8-week-old C57BL / 6J female and male mice 48 hours after ischemia-reperfusion-induced acute kidney injury in Example 1 of this invention. Figure 3 The pathological scores of renal tubular necrosis in 8-week-old C57BL / 6J female and male mice induced by ischemia-reperfusion injury 48 hours after the injury in Example 1 of this invention. Figure 4 The expression level of renal tubular injury factor NGAL in 8-week-old C57BL / 6J female and male mice 48 hours after ischemia-reperfusion induced acute kidney injury in Example 1 of the present invention; Figure 5 The quinolinic acid level in the kidneys of 8-week-old C57BL / 6J female and male mice 48 hours after ischemia-reperfusion-induced acute kidney injury in Example 1 of this invention; Figure 6The serum urea nitrogen level of 8-week-old C57BL / 6J male mice 48 hours after ischemia-reperfusion-induced acute kidney injury (quinolinic acid or NS control treatment) in Example 2 of the present invention. Figure 7 The H&E staining of kidney tissue from 8-week-old C57BL / 6J male mice 48 hours after ischemia-reperfusion-induced acute kidney injury (with quinolinic acid or NS control treatment). Figure 8 The pathological score of renal tubular necrosis in 8-week-old C57BL / 6J male mice 48 hours after ischemia-reperfusion induced acute kidney injury (with quinolinic acid or NS control treatment). Figure 9 The expression level of NGAL, a renal tubular injury factor, in 8-week-old C57BL / 6J male mice 48 hours after ischemia-reperfusion-induced acute kidney injury (with quinolinic acid or NS as control treatment) in Example 2 of this invention. Detailed Implementation

[0017] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0018] This invention discloses the application of quinolinic acid in the preparation of drugs for the prevention and treatment of acute kidney injury (AKI), which is induced by renal ischemia-reperfusion. The drug is an oral formulation used for prophylactic administration in high-risk individuals undergoing iatrogenic procedures at potential AKI risk, and for pretreatment of ischemic conditions in transplanted kidneys. Experiments have shown that quinolinic acid significantly reduces serum urea nitrogen levels in AKI mice, alleviates renal tissue morphological damage, and decreases the expression level of the renal tubular injury factor NGAL protein in AKI mice, demonstrating significant clinical value in the prevention and treatment of AKI.

[0019] Example 1 Seventeen 8-week-old male and female C57BL / 6J mice (9 males and 8 females) were used to establish an ischemia-reperfusion-induced acute kidney injury model by bilateral renal pedicle clamping for 22 minutes. After modeling, mouse weight was measured and recorded daily, and general condition was observed. Forty-eight hours after modeling, both groups of mice were weighed and anesthetized with an intraperitoneal injection of 5% chloral hydrate (0.25 ml / 25 g body weight). Blood was collected from the eyeballs, centrifuged, and the serum was separated and stored at -80°C for blood urea nitrogen analysis. The abdomen was cut along the midline to expose the peritoneum, and both kidneys were separated. The kidneys were placed on pre-prepared ice for tissue sampling. Tissue from both ends of one kidney, mainly cortical tissue, was rapidly frozen in liquid nitrogen and stored at -80°C for subsequent molecular biology experiments and metabolite analysis. The other kidney was fixed in 4% paraformaldehyde solution, dehydrated using a gradient method, embedded in paraffin, and stained with H&E for histopathological observation.

[0020] Serum urea nitrogen was measured in both male and female mice. Figure 1 As shown, after establishing the ischemia-reperfusion-induced acute kidney injury model, the serum urea nitrogen level in male mice was approximately 7-fold higher than that in female mice (79.78±5.810 mmol / L in males and 12.32±2.267 mmol / L in females), and the difference was statistically significant. Figure 2 , Figure 3 As shown, morphologically, the renal tubular necrosis in female mice was less pronounced and less severe than that in male mice under light microscopy, and the pathological damage score was correspondingly lower in female mice (3.200±0.200 for males and 1.200±0.200 for females), with statistically significant differences; Figure 4 As shown, in molecular experiments, the expression level of the renal tubular injury factor NGAL protein in the kidneys of female mice was also lower than that in male mice (0.897±0.043 in male mice and 0.353±0.050 in female mice), and the difference was statistically significant; Figure 5 As shown, more importantly, the quinolinic acid level in the kidney tissue of female mice was significantly higher than that of male mice (0.049±0.004 ng / mg tissue in male mice and 0.113±0.019 ng / mg tissue in female mice), and the difference was statistically significant. These results indicate that, compared with female mice, lower quinolinic acid levels in the kidneys of male mice are associated with aggravated acute kidney injury due to ischemia-reperfusion injury.

[0021] Example 2 Ten 8-week-old male C57BL / 6J mice were used to establish an ischemia-reperfusion-induced acute kidney injury model by bilateral renal pedicle clamping for 22 minutes. Five mice were administered quinolinic acid via gavage (quinolinic acid was administered 48 hours before ischemia-reperfusion for prevention; 25 mg of quinolinic acid was dissolved in 10 ml of physiological saline, and 0.2 ml of the solution was administered to each 20 g mouse via gavage, once daily, with a final administration of quinolinic acid 4 hours before sacrifice, for a total of 5 administrations); the remaining five mice were administered an equal volume of physiological saline via gavage. After modeling, mouse weight and general condition were measured and recorded daily. Mice were sacrificed 48 hours after modeling, and serum and kidneys were collected. Specific procedural details are as described in Example 1.

[0022] After 5 days of quinolinic acid treatment in male rats, as Figure 6 As shown, serum urea nitrogen (BUN) levels in mice treated with quinolinic acid (QA) were significantly lower than those in the control group after the establishment of the ischemia-reperfusion acute kidney injury model (QA group 25.73±4.459 mmol / L, NS group 45.29±5.844 mmol / L), with statistically significant differences. Figure 7 , Figure 8As shown, morphological examination under light microscopy revealed significant improvement in renal morphological damage and a decrease in the renal tubular injury score (QA group 0.720±0.167, NS group 2.000±0.174), with statistically significant differences. Figure 9 As shown in the molecular experiments, the expression level of the renal tubular injury factor NGAL protein in the kidneys of the treatment group was also lower than that in the control group (QA group 0.478±0.051, NS group 0.880±0.149), and the difference was statistically significant. These results indicate that quinolinic acid supplementation can alleviate ischemia-reperfusion-induced acute kidney injury.

[0023] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. Application of quinolinic acid in the preparation of drugs for the prevention and treatment of acute kidney injury.

2. The application according to claim 1, characterized in that, The acute kidney injury referred to here is acute kidney injury induced by renal ischemia-reperfusion.

3. The application according to claim 1, characterized in that, The drug is an oral preparation.

4. The application according to claim 1, characterized in that, The drug is used for prophylactic administration in high-risk individuals undergoing iatrogenic procedures that may pose a potential risk of acute kidney injury.

5. The application according to claim 1, characterized in that, The drug is used for the pretreatment of ischemic conditions in transplanted kidneys.

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