Application of Mindin as early biomarker in prediction or diagnosis of acute kidney injury

Abstract

The invention discloses application of Mindin as an early-stage biomarker in prediction or diagnosis of acute kidney injury, belongs to the technical field of biology, and relates to a method for early diagnosis of AKI (acute kidney injury), the early-stage serum biomarker of acute kidney injury is determined by analyzing the concentration of Mindin protein in serum of a normal person and a patient with acute kidney injury. The relationship between serum Mindin and acute kidney injury is analyzed by using an independence test, the occurrence of AKI (acute kidney injury) is predicted in an early stage, the purpose of preliminarily screening patients is achieved, and a kit with high specificity is applied to patients with increased screening for further definite diagnosis. The application method of the Mindin as the early biomarker in predicting or diagnosing the acute kidney injury has important significance in early diagnosis and prognosis of the acute kidney injury.

Description

Technical Field

[0001] The present invention belongs to the field of biotechnology, and specifically relates to an application of Mindin as an early biomarker in predicting or diagnosing acute kidney injury. Background Art

[0002] Acute Kidney Injury (AKI) is a common clinical problem and the main cause of renal dysfunction. It is associated with high morbidity and mortality and is usually caused by injuries such as renal ischemia-reperfusion (IR) injury, severe myocardial dysfunction, hypovolemia, sepsis or nephrotoxins. It not only increases the personal economic burden, but is also closely related to prolonged hospitalization and poor clinical outcomes. Statistics show that the incidence and mortality of acute kidney injury are increasing year by year, with an incidence of 10-15% in hospitalized patients and even as high as 58% in intensive care units. Some milder AKI can restore renal function through supportive care or renal replacement therapy, but more than 50% of AKI will eventually develop into chronic kidney disease (CKD). However, there is no effective treatment to prevent AKI or promote AKI recovery in the clinic. It is urgent to study the transformation mechanism of AKI to CKD and find potential therapeutic targets and strategies. Although we have made some progress in the study of pathogenesis and new therapeutic targets in recent years, doctors still do not have effective and specific treatment strategies.

[0003] The current standard for diagnosing AKI is an acute decline in glomerular filtration rate (GFR), as evidenced by an acute increase in serum creatinine (Scr) levels or a decrease in urine output (UO) over time. Many studies have shown that new biomarkers are more sensitive than serum creatinine and urine output in detecting AKI in certain populations. Specifically, there is an unmet need for early detection of patients with AKI before AKI progresses to the point of requiring renal replacement therapy. Biomarker-guided management may help identify high-risk patient groups who progress to severe AKI and determine when to start renal replacement therapy and the optimal follow-up period.

[0004] Early diagnosis and treatment of AKI are crucial, and the development of new early biomarkers can help achieve this goal. By looking for specific biomarkers, we can detect the occurrence of AKI earlier and take treatment measures early, thereby reducing the severity of the disease and the risk of complications for patients. Therefore, researching and developing new early biomarkers of acute kidney injury is an important task, which can make an important contribution to improving the diagnosis and treatment level and quality of life of patients. In order to ensure the health of patients with acute kidney injury in my country and ensure the safety of their treatment, it is urgently necessary to research and develop new early biomarkers of acute kidney injury. Summary of the invention

[0005] The purpose of the present invention is to provide a use of Mindin as an early biomarker in predicting or diagnosing acute kidney injury in response to the existing problems.

[0006] The present invention is achieved through the following technical solutions:

[0007] Application of Mindin as an early biomarker in the prediction or diagnosis of acute kidney injury.

[0008] Furthermore, the specific application method is evaluated by measuring the content of Mindin protein.

[0009] Furthermore, the Mindin protein content includes serum Mindin protein content and kidney tissue Mindin protein content.

[0010] Furthermore, the serum Mindin protein content is detected by enzyme-linked immunosorbent assay.

[0011] Furthermore, the content of Mindin protein in kidney tissue is detected by immunofluorescence method.

[0012] Furthermore, the Mindin protein content is proportional to the severity of acute kidney injury.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. Mindin is an acute response phase protein, mainly located outside the cell membrane. It is a small molecule protein that plays an important role in mediating natural immunity and inflammation. The present invention provides the use of serum Mindin in the early diagnosis of acute kidney injury. The present invention first discovered that Mindin is significantly increased in the serum and renal tissue of acute kidney injury, and Mindin can be used as an early biomarker for diagnosing acute kidney injury. The method for using Mindin as an early biomarker in predicting or diagnosing acute kidney injury provided by the present invention is of great significance for the early diagnosis and prognosis of acute kidney injury.

[0015] 2. The method for early diagnosis of AKI of the present invention determines the early serum biomarker of acute kidney injury by analyzing the concentration of Mindin protein in the serum of normal people and patients with acute kidney injury, and uses an independent test to analyze the relationship between serum Mindin and acute kidney injury, so as to predict the occurrence of AKI at an early stage and achieve the purpose of preliminary screening of patients. For patients with increased screening results, a highly specific test kit is used for further diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is an analysis chart of the clinical correlation and prognostic diagnostic value of Mindin in patients with acute kidney injury;

[0017] Figure 2 Analysis chart of the results of Mindin, a core gene in acute kidney injury, discovered through data mining;

[0018] Figure 3 The results of the expression and localization of Mindin in the kidney tissue removed from patients with hydronephrosis;

[0019] Figure 4 Predict Mindin m6A modification site map for SRAMP;

[0020] Figure 5 The results of the Mindin and macrophage expression levels in the kidneys of normal control mice and mice with ischemia-reperfusion (24h, 7d and 14d); DETAILED DESCRIPTION

[0021] In order to further explain the present invention, it is described below in conjunction with the following specific embodiments.

[0022] Mindin is an extracellular matrix protein of the SPON-F-Sondin family, mainly distributed in tissues such as the liver, kidney, lung, and vascular endothelial cells. It can affect the formation and organizational structure of the extracellular matrix, regulate the function of T cells and macrophages, and participate in inflammatory responses and the migration of immune cells. Studies have found that serum Mindin is significantly increased in diabetic nephropathy and is closely related to the severity of the disease; studies on brain and liver ischemia-reperfusion injury have found that inhibition of Mindin can reduce epithelial cell damage and inflammatory responses caused by ischemia-reperfusion injury (IRI), and at the same time enhance the proliferation and repair of surviving cells; and specific knockout of Mindin can reduce cell apoptosis and inflammatory responses after cerebral ischemia-reperfusion injury and inhibit apoptosis of normal brain cells by activating Akt and inhibiting the NF-κB signaling pathway. At the same time, specific knockout of Mindin in hepatocytes can directly inhibit inflammatory responses in hepatocytes and promote hepatocyte regeneration. The above studies indicate that Mindin may mediate the cell damage and proliferation and repair process caused by ischemia-reperfusion organ injury. Furthermore, the present invention discovered for the first time that Mindin is significantly elevated in the serum and renal tissue of acute kidney injury. Therefore, Mindin of the present invention can be used as an early biomarker for diagnosing acute kidney injury, providing a new diagnostic method for clinical practice.

[0023] Example 1

[0024] Clinical trials

[0025] The steps for collecting and testing patient serum include:

[0026] S1. Collect blood from patients on the first day after enrollment. After venipuncture, blood was drawn and collected into heparinized tubes;

[0027] S2. After the blood is collected, let it stand for 30 minutes, centrifuge it at 2-8℃ and 4000rpm / min for 10 minutes, take the supernatant, divide it into portions, and store it in a -80℃ refrigerator;

[0028] S3, quantitatively determine the content of Mindin in plasma by double antibody sandwich ELISA within 25-35 days after specimen collection;

[0029] S4, coating each marker antibody in a 96-well microplate to prepare a solid phase carrier, with standard wells, test sample wells, and blank wells respectively;

[0030] S5. Set 7 standard wells, add 100uL of standard products of different concentrations in sequence, add 100uL of standard product diluent to the blank well, and add 100uL of the sample to be tested to make each marker into a solid phase carrier;

[0031] S6, add 100uL of the sample to be tested to each of the microwells of the sample to be tested, wherein the marker protein binds to the antibody connected to the solid phase carrier, and then add the biotinylated specific antibody, and then wash the unbound biotinylated antibody, and then add HRP-labeled avidin;

[0032] S7. After thorough washing again, TMB substrate is added for color development. TMB is converted into blue under the catalysis of peroxidase and then into the final yellow under the action of acid. The depth of the color is positively correlated with the concentration of the marker protein in the sample.

[0033] S8. Measure the absorbance (OD value) at a wavelength of 450 nm using an enzyme-labeled instrument and calculate the sample concentration;

[0034] S9. Plot the average values ​​of the duplicate wells of each standard and the OD values ​​of the samples after deducting the OD value of the blank well (seven-point graph), with the concentration of the standard as the ordinate (or logarithmic coordinate), and the OD value as the abscissa (or logarithmic coordinate). Detect the standard curve (software name), find the corresponding concentration from the standard curve, calculate the regression equation of the standard curve using the concentration of the standard and the OD value, substitute the OD value of the sample into the equation, and calculate the sample concentration, which is the actual concentration of the sample.

[0035] The age of the patients described in step S1 was between 18 and 80 years old. Patients with any of the following were excluded: previous sepsis, coronary heart disease, etc.; history of dialysis or kidney transplantation; pregnancy; previous history of chronic kidney disease; and combined renal trauma.

[0036] The primary outcome of the above trial was the association between Mindin and the incidence of AKI 7 days after admission in patients with acute kidney injury, and the secondary outcome was the ability to evaluate biomarkers and clinical parameters.

[0037] The level of Mindin protein in blood was detected by enzyme-linked immunosorbent assay.

[0038] All operations in this experiment were approved by the Ethics Committee of Tongren Hospital Affiliated to Wuhan University.

[0039] Mindin has significant clinical relevance and diagnostic value in patients with acute kidney injury. Figure 1 As shown:

[0040] The present invention collected serum samples from 20 healthy people and 20 patients with acute kidney injury to evaluate the correlation between Mindin expression and renal function. Compared with healthy people, the levels of Mindin protein, renal function indicators serum creatinine (Scr) and urea nitrogen (BUN) in the peripheral blood of patients with acute kidney injury were significantly increased (P<0.001)( Figure 1 AC). Subsequently, it was proved that Mindin level was significantly correlated with serum creatinine and urea nitrogen levels (P<0.05) ( Figure 1 DE). The ROC curve showed that in the renal injury patient dataset GES66494, the area under the curve (AUC) of Mindin was 0.946 (95% CI: 0.884–1.000; p<0.001) ( Figure 1 F), indicating the potential possibility of Mindin as a molecular marker for the diagnosis of acute kidney injury. In summary, Mindin is a potential molecular marker for acute kidney injury.

[0041] Figure 1 middle:

[0042] (A) Expression level of Mindin protein in peripheral blood of patients with acute kidney injury.

[0043] (BC) Expression levels of serum creatinine (Scr) and blood urea nitrogen (BUN) in the peripheral blood of patients with acute kidney injury.

[0044] (DE) Pearson correlation analysis between Mindin and serum creatinine (Scr) and blood urea nitrogen (BUN).

[0045] (F) The receiver operating characteristic (ROC) curve of Mindin was drawn using the renal injury patient dataset GES66494, and the area under the curve (AUC) was calculated.

[0046] *P<0.05; **P<0.01; ns, no significant difference.

[0047] The necrotic renal tissues of patients with hydronephrosis were obtained, and the expression and localization of Mindin were observed by immunofluorescence.

[0048] The results showed that Mindin protein was highly expressed in the kidney tissue of patients with hydronephrosis, and the infiltration of macrophages in the kidney increased. Figure 2 .

[0049] Figure 2 middle:

[0050] The picture on the right is the enlarged area of ​​the box on the left.

[0051] Example 2

[0052] Animal experiments

[0053] Construction of a mouse model of acute renal injury induced by ischemia-reperfusion

[0054] 1. Animal modeling

[0055] 1.1 Treatment of mice in the ischemia-reperfusion group (IR)

[0056] S1. All experimental mice in this study were anesthetized intraperitoneally with sodium pentobarbital at a concentration of 50 mg / kg;

[0057] S2. Use an animal shaver to shave the hair in the surgical area on both sides of the mouse's back, then use a cotton swab or gauze to soak a small amount of physiological saline to remove the remaining hair in the surgical area, and then use a cotton ball soaked in 1% active iodine liquid to disinfect the surgical incision from the inside to the outside three times. After treatment, spread a towel and make a longitudinal incision on the skin about 1 cm on the side of the spine near the lowest rib of the mouse;

[0058] S3, the fascia and muscles of the mice were separated in sequence, and then the perirenal fat tissue and fascia were bluntly freed using a glass needle and ophthalmic fiber forceps to expose the bilateral renal pedicles, and the bilateral renal arteries were clamped for 30 minutes using micro-artery clamps;

[0059] S4. Successful ischemia is indicated by observing the color of the kidneys gradually changing from pink to bright red or cherry purple. Then, the micro-arterial clamp is released and the color of both kidneys is observed to gradually recover from bright red or cherry purple to pink, indicating successful reperfusion. Sterile suture needles are then used to close the surgical incision layer by layer.

[0060] The entire operation was performed on a constant temperature operating table to ensure that the body temperature of the mice remained at 37°C. After the operation, the mice were transferred to a 37°C constant temperature box and placed in a cage after they were fully awake.

[0061] 1.2 Treatment of sham-operated mice

[0062] The same surgical approach was performed, but without renal artery clamping.

[0063] Ten weeks after surgery, anesthetize with an overdose of sodium pentobarbital, remove the whiskers of mice, remove the eyeballs of mice with curved forceps to collect blood, place the blood specimens at 2-8℃ for 30 minutes, centrifuge at 1000rpm for 10 minutes, take the supernatant and aliquot, and store in a -80℃ refrigerator; all experimental mice are killed. Quickly remove the mouse kidneys and place them on ice, remove the renal capsule, and then use a blade to cut the kidney tissue longitudinally into two halves, one half is immersed in 4% paraformaldehyde solution for pathological analysis, and the other half of the kidney tissue is placed in a cryopreservation tube and put into a liquid nitrogen tank, then transferred to an ultra-low temperature refrigerator for storage for molecular biology experimental detection.

[0064] The experimental animals in this part were divided into sham operation group (Sham) and ischemia-reperfusion group (IR), with 10 mice in each group.

[0065] All operations in this experiment complied with the Guidelines for the Care and Use of Laboratory Animals and the Guiding Opinions on the Ethical Treatment of Laboratory Animals and other regulations, and were approved by the Experimental Animal Ethics Committee of the Tongren Hospital Affiliated to Wuhan University.

[0066] 2. Experimental testing

[0067] 2.1 Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR)

[0068] (1) RNA extraction

[0069] RNA was extracted using the OMEGA (R6934-01) kit as follows:

[0070] 1) Add 1 mL RNA-Solv Reagent to the reagent and add an appropriate amount of tissue sample (no more than 30 mg);

[0071] 2) After standing at room temperature for 5 min, add 200 μL of chloroform and vortex for 20 s using a mixer to ensure adequate mixing;

[0072] 3) After the mixture was allowed to stand at room temperature for 2 to 3 minutes, it was centrifuged at 12,000 rpm for 15 minutes to separate the aqueous layer and the organic layer;

[0073] 4) Next, take 500 μL of the upper aqueous phase and transfer it to a new 1.5 mL microcentrifuge tube, add an equal volume of 70% anhydrous ethanol, and vortex thoroughly to mix. Then, insert the centrifuge column into a 2 mL collection tube, transfer 700 μL of the sample into the centrifuge column, perform high-speed centrifugation at 12,000 rpm, and then discard the filtered liquid;

[0074] This step needs to be repeated until most of the RNA is filtered out of the centrifugal column;

[0075] 5) After that, add 500 μL RNA Wash Buffer 1 solution to the centrifuge tube and continue centrifugation at 12000 rpm, then discard the filtrate and reuse the collection tube;

[0076] 6) Next, add 500 μL of RNA Wash Buffer 2 diluted with 100% anhydrous ethanol to the centrifuge column, centrifuge at 12,000 rpm, discard the filtrate and reuse the collection tube;

[0077] This step needs to be repeated once;

[0078] 7) Afterwards, centrifuge again at 12000 rpm for 2 min to dry the centrifuge column;

[0079] 8) Finally, place the centrifuge column in a 1.5 mL enzyme-free centrifuge tube, add 50 μL DEPC water and centrifuge at high speed for 2 minutes, and finally freeze the extracted RNA in a -80°C refrigerator.

[0080] (2) Reverse transcription

[0081] 1) To ensure the consistency and accuracy of the experiment, the present invention uniformly quantifies the sample concentration as 1 μg, and accurately calculates the required sample volume, and then uses enzyme-free water to fill the total volume to 14 μL;

[0082] 2) Denature the RNA at 65°C for 5 min using a metal bath and immediately cool it on ice to prevent RNA renaturation;

[0083] 3) Using the Toyobo kit (FSQ-101), add 6 μL of reagent in proportion to prepare a 20 μL reaction system;

[0084] 4) Use the reverse transcription equipment of Bio-Rad to perform reverse transcription reaction at 37°C for 15 min;

[0085] 5) Then, the enzyme inactivation reaction was carried out at 98°C for 5 minutes. After all reactions were completed, the cDNA was stored at 4°C or -20°C.

[0086] (3) qRT-PCR

[0087] 1) Using cDNA as the template of the PCR reaction system, a Bio-Rad fluorescence quantitative detection PCR instrument was used to perform qRT-PCR detection on the sample to be tested;

[0088] Reagents were purchased from Servicebio;

[0089] The preparation system is as follows:

[0090] 2x Universal Blue SYBR Green qPCR Master Mix 10 μL; Forward Primer (10 μM) 0.4 μL; Reverse Primer (10 μM) 0.4 μL; cDNA 1 μL; and adjust the total volume to 20 μL with enzyme-free water.

[0091] Primer sequences are shown in Table 1.

[0092] Table 1 Primer list

[0093]

[0094] 2) The cycling conditions are set as follows: the initial denaturation phase is carried out at 95°C for 2 minutes, followed by a cycling phase, including denaturation at 95°C for 5 seconds, annealing at 58°C for 30 seconds, and extension at 72°C for 30 seconds. This cycle will be repeated 45 times and finally enter the melting phase. By analyzing the green fluorescence signal in the PCR melting curve and amplification curve of the sample, a threshold can be set in the linear growth part of the curve. The cycle number corresponding to the intersection of this threshold and the amplification curve of the sample to be tested is defined as the Ct value. The relative expression of the gene is calculated by 2 -△△Ct Methods Statistical analysis was performed.

[0095] 2.1 Enzyme-linked immunosorbent assay (ELISA)

[0096] 2.1.1 Sample preparation

[0097] Plasma sample: Collect whole blood into a test tube containing an anticoagulant, mix well, place on ice, centrifuge at approximately 4000 rpm at 4°C for 10 min, and take the yellow or light yellow supernatant to obtain plasma.

[0098] 2.2.2 Reagent preparation

[0099] Before use, all components must be warmed up for at least 120 minutes to ensure they are fully warmed to room temperature.

[0100] Concentrated detergent: The concentrated detergent taken out of the refrigerator will have crystals, which is normal. Heat it in a water bath to completely dissolve the crystals. Dilute the concentrated detergent and distilled water at a ratio of 1:20, that is, add 19 parts of distilled water to 1 part of concentrated detergent.

[0101] Substrate: Substrate solution A and B should be mixed thoroughly at a volume ratio of 1:1 before use and used within 15 minutes after mixing. All reagents and components should be returned to room temperature. It is recommended to perform duplicate wells for standards, quality controls and samples.

[0102] 2.2.3 Specific experimental steps

[0103] S1. Prepare the working solution of each component according to the instructions;

[0104] S2. Take out the required strips from the aluminum foil bag; seal the remaining strips with a ziplock bag and put them back in the refrigerator. Set up standard wells, 0 value wells, blank wells and sample wells. Add 50 μL of standard with different concentrations to the standard wells, 50 μL of sample diluent to the 0 value wells, nothing to the blank wells, and 50 μL of the sample to be tested to the sample wells;

[0105] S3. Add 100 μL of detection antibody labeled with horseradish peroxidase (HRP) to the standard wells, 0 value wells and sample wells except the blank wells;

[0106] S4. Cover the reaction plate with a sealing film and incubate in a 37°C water bath or incubator in the dark for 60 min.

[0107] S5. Remove the sealing film, discard the liquid, pat dry on absorbent paper, fill each well with washing solution, let stand for 20 seconds, shake off the washing solution, pat dry on absorbent paper, and repeat this 5 times; if using an automatic plate washer, please wash the plate according to the operating procedures of the plate washer, and add a 30-second soaking procedure to improve the accuracy of the test; after washing, before adding the substrate, pat the reaction plate dry on a clean, non-chipping paper;

[0108] S6. Mix substrate A and B in a 1:1 volume ratio, add 100 μL of the substrate mixture to all wells, cover the reaction plate with a sealing film, and incubate in a 37°C water bath or incubator in the dark for 15 min;

[0109] S7. Add 50 μL of stop solution to all wells and read the absorbance (OD value) of each well on a microplate reader.

[0110] Result calculation: With the concentration of the standard as the horizontal axis (6 standard wells, plus 1 0-value well, a total of 7 concentration points), and the corresponding absorbance (OD value) as the vertical axis, computer software is used to use the four-parameter Logistic curve fitting (4-p1) to create a standard curve equation, and the sample concentration value is calculated using the equation through the sample absorbance (OD value). If the sample is diluted, the concentration value measured by the above method must be multiplied by the dilution factor to obtain the final concentration of the sample.

[0111] 3. Results

[0112] The Gene Expression Omnibus (GEO) of the National Center for Biotechnology Information (NCBI) aims to archive and make public microarray and other high-throughput data generated by the scientific community for free use by researchers worldwide. The GEO database has a complete infrastructure that complies with the Minimum Information Standard for Microarray Experiments (MIAME), ensuring that both raw and processed data with complete annotations are captured and stored. The database supports a variety of data storage options and formats, including but not limited to NetTables, Spreadsheets, Extensible Markup Language (XML), and text files in Simple General Format (SOFT). In addition to data storage capabilities, GEO also provides a series of user-friendly web interfaces and applications that enable users to efficiently explore, visualize, and download thousands of experimental data and tens of millions of gene expression patterns stored in GEO. This article describes the structure and user facilities of the GEO database in detail, and focuses on the latest progress in database design, performance optimization, extension of submission format options, and updates to data query and retrieval utilities. Researchers can obtain the latest information and data resources of the GEO database by visiting the following website: http: / / www.ncbi.nlm.nih.gov / geo / .

[0113] The present invention uses six data sets of the GEO database (GSE66494, GSE87025, GSE36496, GSE217654, GSE96102, GSE217650) to analyze differentially expressed genes. Through UpSet graph analysis, it is found that genes such as Mindin, HAVCR1, and FKBP10 are core regulatory genes in the process of renal injury ( Figure 3 AB). At the same time, we analyzed the GSE66494 dataset and found that the expression of Mindin in CKD patients was significantly increased ( Figure 3 C).

[0114] The present invention uses the online tool SRAMP (http: / / www.cuilab.cn / sramp / ) to predict all possible m6A sites in the m6A peak region sequences of three mouse-derived and one human-derived Mindin genes, and predicts additional m6A methylation sites ( Figure 4 ).

[0115] In addition, the present invention established a mouse renal ischemia-reperfusion model, further proving that the expression level of Mindin in renal tissue and serum was significantly increased in the model group and reached a peak at 24h ( Figure 1DE). Compared with the normal control group, Mindin protein and macrophages were highly expressed and co-localized in the renal tissue of mice after ischemia-reperfusion. As the reperfusion time prolonged, its expression first increased (24h) and then gradually decreased (7d, 14d) ( Figure 3 DE), the above results indicate that Mindin may regulate the process of acute kidney injury as a core gene.

[0116] Figure 3 middle:

[0117] (A) UpSet graph shows the differentially expressed genes in the datasets (GSE66494, GSE87025, GSE36496, GSE217654, GSE96102, GSE217650).

[0118] (B) Volcano plot showing upregulated and downregulated genes in the dataset GSE217650.

[0119] (C) The expression level of Mindin was significantly increased in CKD patients in the GSE66494 dataset.

[0120] (D) After renal ischemia-reperfusion in mice, the expression level of Mindin mRNA in renal tissue was detected by qRT-PCR at 24h, 7d, and 14d.

[0121] (E) After renal ischemia-reperfusion in mice, the levels of Mindin in serum were detected by ELISA at 24 h, 7 d, and 14 d.

[0122] *P<0.05; **P<0.01; ***P<0.001; ns, no significant difference.

[0123] Mindin expression in the renal tissue and peripheral blood of mice at different time points after ischemia-reperfusion. Compared with the normal control group, Mindin protein was abundantly expressed in the renal tissue of mice after ischemia-reperfusion and co-localized in macrophages. With the extension of reperfusion time, its expression first increased (24h) and then gradually decreased (7d, 14d) ( Figure 5 ).

[0124] In summary, Mindin protein is significantly increased in the renal tissue of acute kidney injury, and Mindin protein is significantly increased in the serum of acute kidney injury. It can be inferred that Mindin protein can be used as an early biomarker of acute kidney injury.

Claims

1. Application of Mindin as an early biomarker in the prediction or diagnosis of acute kidney injury.

2. The use according to claim 1, characterized in that: The specific application method is to conduct evaluation by measuring the content of Mindin protein.

3. The use according to claim 2, characterized in that: The Mindin protein content includes the serum Mindin protein content and the kidney tissue Mindin protein content.

4. The use according to claim 3, characterized in that: The serum Mindin protein content is detected by enzyme-linked immunosorbent assay.

5. The use according to claim 3, characterized in that: The content of Mindin protein in kidney tissue is detected by immunofluorescence method.

6. The use according to claim 3, characterized in that: The Mindin protein content is proportional to the severity of acute kidney injury.

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