JP6083937B2 - Test method for acute kidney injury - Google Patents

Description

  The present invention relates to a test method for acute kidney injury including detection of extracellular region megalin in urine, and a reagent for testing acute kidney injury used in the test method, including an anti-extracellular region megalin antibody.

  In recent years, acute renal failure (ARF) has been focused not only on structural abnormalities such as acute tubular necrosis, but also on functional abnormalities in renal hemodynamics. Diagnosis and treatment have also changed from ARF to the concept of acute kidney injury (AKI), and the importance of early diagnosis and treatment has been proposed.

  Acute kidney injury refers to a condition in which kidney function is rapidly reduced, and many acute kidney injury is characterized by decreased kidney function due to tubular necrosis. Causes of acute kidney injury include prerenal renal failure, renal parenchymal renal failure, and postrenal renal failure. Prerenal renal failure is due to traumatic bleeding, dehydration, vomiting, decreased extracellular fluid volume such as diarrhea, decreased effective circulating blood volume such as cardiogenic shock, and dissecting aortic aneurysm, renal artery thrombosis, etc. This occurs when the kidney is exposed to ischemia due to a decrease in renal blood flow. Renal parenchymal renal failure is glomerular (acute glomerulonephritis, rapidly progressive glomerulonephritis, polyarteritis nodosa, etc.), acute tubular necrosis (antibiglycoside antibiotics, anti-inflammatory analgesics, antitumor) Injury directly to the kidney tissue, such as those caused by drugs, contrast agents, etc.) and acute interstitial nephritis (due to antibiotics such as β-lactams, anti-inflammatory analgesics, anticonvulsants, etc.). In postrenal renal failure, urinary obstruction (ureter stones), bladder, urethral obstruction (prostatic hypertrophy, prostate cancer), pelvic tumors, etc., occur during the passage of urine, resulting in impaired urinary excretion It is what

  Acute kidney injury is known as a renal disease that may be combined in cases requiring management in an intensive care unit, such as after open heart surgery or aortic replacement, and a patient requiring intensive treatment has acute kidney injury It has been reported that the mortality rate is as high as about 50%.

  Therefore, it is necessary to grasp the pathological condition in time units after onset. At present, improvement in the prognosis of acute kidney injury cannot be achieved without early diagnosis and intervention.

  At present, diagnosis of acute kidney injury is usually performed by serum creatinine and urine volume, but there is a problem in diagnosis by these two items. No diagnostic criteria have been established for these two items, and there are 35 definitions of acute kidney injury. In order to solve this problem, as a global effort, an acute kidney injury network was created, and diagnostic criteria for acute kidney injury were proposed. In the diagnostic criteria, (1) Serum creatinine is increased 1.5 times or more, or 0.3 mg / dL or more, (2) 0.5 mL / kg oliguria per hour continues for 6 hours or more, It has been shown to diagnose acute kidney injury. Furthermore, similar to the stage classification of chronic kidney disease, the stage classification of acute kidney injury (RIFLE classification, AKIN classification, etc.) has been proposed.

  However, problems still exist in the diagnosis based on the above two items. Serum creatinine does not rise immediately even when glomerular filtration rate decreases due to renal injury, while serum creatinine may continue to rise for a while even if glomerular filtration rate tends to recover. It is not very useful as an early marker for detecting acute changes, monitoring of therapeutic effects, and a prognostic marker. In addition, serum creatinine is susceptible to extrarenal factors such as weight, race, sex, drugs, muscle metabolism, and nutritional status. In addition, since the amount of urine takes time to diagnose, it is not suitable as a marker for acute kidney injury that requires understanding the pathological condition in units of time after onset. Therefore, there is an urgent need to develop a biomarker that is easy to measure and is not easily affected by other biological factors, and that enables early detection of disease, risk classification, and prognosis prediction.

  Urinary megalin is a substance found in connection with renal diseases, and a simple means for examining renal injury by measuring urinary megalin has been disclosed (Patent Documents 1 and 2).

  Megalin, also known as Glycoprotein 330 (gp330) or Low Density Lipoprotein (LDL) -receptor relate protein 2 (LRP2), is a glycoprotein with a molecular weight of approximately 600 kDa expressed in the proximal tubular epithelial cells of the kidney ( Non-patent documents 1, 2).

  There are two types of megalin in cell culture experiments using renal proximal tubular epithelial cells: membrane-bound full-length megalin and Soluble-Form (fragment containing extracellular region) lacking the intracellular region. (Non-patent Document 3), and a method for measuring full-length human megalin, extracellular region, and intracellular region in urine has also been reported (Patent Document 3).

International Publication No. WO2002 / 037099 International publication WO2010 / 126055 International Publication No. WO2010 / 126043

Christensen E.I., Willnow T.E. (1999) J. Am. Soc. Nephrol. 10, 2224-2236 Zheng G, McCluskey R.T. et al. (1994) J. Histochem. Cytochem. 42, 531-542 Flavia F.J., Julie R.I. et al. (1998) Kidney. International. 53, 358-366

  An object of the present invention is to provide a test method capable of detecting acute kidney injury early and a test method for determining the onset risk of acute kidney injury. For example, patients with high risk of complication of acute kidney injury after open heart surgery are provided. It is an object of the present invention to provide an inspection method that can be predicted before surgery.

  In order to solve the above problems, the present inventors have focused on the fact that the amount of urinary extracellular region megalin excreted in patients with a high risk of acute kidney injury is higher than that in healthy subjects or patients without acute kidney injury, The inventors have found that by detecting extracellular region megalin, it is possible to test for acute kidney injury and the risk of developing acute kidney injury, thereby completing the present invention.

That is, this invention consists of the following.
[1] A test method for detecting acute kidney injury by detecting urinary extracellular region megalin.
[2] The testing method according to [1], wherein acute renal injury is determined when the urinary extracellular region megalin level is higher than a reference value.
[3] A test method for evaluating the risk of developing acute kidney injury by measuring urinary extracellular region megalin in a subject.
[4] The test method according to [3], wherein when the urinary extracellular region megalin level is higher than a reference value, the risk of developing acute kidney injury is high.
[5] The examination method according to [4], wherein the subject is an ICU inpatient who is admitted to an ICU (intensive care unit) or a patient who is admitted to a general ward.
[6] A test method for evaluating the risk of complication of acute kidney injury after cardiac surgery by measuring urinary extracellular region megalin in a subject before cardiac surgery.
[7] The test method according to [6], wherein when the urinary extracellular region megalin level is higher than a reference value, the risk of complication of acute kidney injury is high.
[8] The testing method according to any one of [1] to [7], wherein urinary megalin is detected by an immunological technique.
[9] A reagent for testing acute kidney injury, which is used in the testing method according to [8], comprising an anti-megalin antibody for detecting urinary megalin.
[10] An acute kidney injury test reagent kit used for the test method according to [9], comprising a reagent for detecting urinary megalin using an anti-megalin antibody.

  The test method of the present invention makes it possible to determine the risk of developing acute kidney injury that could not be determined by conventional test methods.

It is a figure which shows the result (Example 2) which compared the amount of urinary extracellular region megalin excretion of a healthy person and an acute kidney injury patient. It is a figure which shows the result (Examples 3 and 4) which compared the amount of urinary extracellular area | region megalin excretion of an acute kidney injury onset patient and an acute kidney injury non-onset patient. It is a figure which shows the result (Example 4) which compared the alpha1-microglobulin of an acute kidney injury onset patient and an acute kidney injury non-onset patient. It is a figure which shows the result (Example 4) which compared the beta2-microglobulin of an acute kidney injury onset patient and an acute kidney injury non-onset patient. It is a figure which shows the result (Example 4) which compared the N-acetyl- (beta) -D-glucosaminidase of the acute kidney injury onset patient and the acute kidney injury non-onset patient. It is a figure which shows the result (Example 4) which compared Neutrophil gelatinase-associated lipocalin (N-gal) of an acute kidney injury onset patient and an acute kidney injury non-onset patient.

  The present invention is characterized by testing for acute kidney injury by detecting an extracellular region fragment of megalin present in the urine of a subject.

  Full-length human megalin consists of the amino acid sequence from the 26th to the 4655th amino acid sequence shown in SEQ ID NO: 2. SEQ ID NO: 1 shows the base sequence of human megalin. Shown in SEQ ID NO: 2. The 1st to 25th sequences of the amino acid sequence are signal peptide sequences. The amino acid sequence of human megalin is disclosed in NCBI (National Center for Biotechnology Information) Accession No .: NP_004516 (RefSeq protein ID: 126012573). Human megalin is a single transmembrane glycoprotein composed of three regions: an extracellular region, a transmembrane region, and an intracellular region. A region consisting of the 26th to 4424th amino acids of the amino acid sequence shown in SEQ ID NO: 2 is referred to as the extracellular region of human megalin. The extracellular region fragment of human megalin includes a part or all of the extracellular region, and means a part or all of the region consisting of the 26th to 4424th amino acids of the amino acid sequence shown in SEQ ID NO: 2. Refers to the lack of an intracellular region. Examples of the human megalin extracellular region fragment lacking the intracellular region include a fragment consisting of the 26th to 4361th amino acid sequences of the amino acid sequence shown in SEQ ID NO: 2. This fragment is the remaining extracellular region-side fragment generated in the process of forming a primary cleavage product consisting of the amino acid sequence from 4362 to 4655 of the amino acid sequence shown in SEQ ID NO: 2. Furthermore, examples of the human megalin extracellular region fragment lacking the intracellular region include a fragment consisting of the 4362th to 4437th amino acid sequences of the amino acid sequence shown in SEQ ID NO: 2. This fragment is the remaining extracellular region-containing fragment formed in the above-mentioned secondary cleavage product formation process, consisting of the amino acid sequence from the 4438th to the 4655th amino acid sequence of the amino acid sequence shown in SEQ ID NO: 2.

  In the present invention, an extracellular region fragment lacking an intracellular region is referred to as “extracellular region megalin”.

  In the present invention, extracellular region megalin excreted in urine is measured. In this specification, urine as a specimen may be obtained from any subject. The method for collecting urine is not limited, but it is preferable to use early morning urine or occasional urine. The amount of urine necessary for the test method of the present invention is about 10 to 200 μL. The test method of the present invention may be performed simultaneously with a conventional general urine test. The present invention is also aimed at predicting the risk of developing acute kidney injury after cardiac surgery such as open heart surgery or aortic replacement. In this case, the urine sample should be collected before surgery. Collect. The urine sample can be treated by adding a treatment solution to the collected urine and mixing it. The treatment solution may be any solution as long as it can adjust the pH of urine, mask urine sediment and / or solubilize extracellular megalin, but preferably a chelating agent or a surfactant in a buffer solution. Examples of the solution are as follows. The buffer solution and the chelating agent may be any known one, and the surfactant is preferably a nonionic surfactant. Examples of the treatment liquid include a solution containing 0.2M EDTA and 10% (Vol./Vol.) TritonX-100 in 2M Tris-HCl (pH 8.0). A urine sample solution can be obtained by adding 10 μL of the treatment solution to 90 μL of a urine sample and mixing them.

  Various methods are conceivable as a method for detecting extracellular region megalin from a urine sample solution. An example of a method for detecting extracellular region megalin is an immunological technique. Immunological methods include, for example, immunostaining (including fluorescent antibody method, enzyme antibody method, heavy metal labeled antibody method, radioisotope labeled antibody method), separation by electrophoresis and fluorescence, enzyme, radioisotope, etc. Methods combined with detection methods (including Western blotting and fluorescence two-dimensional electrophoresis), enzyme immunoassay adsorption (ELISA), dot blotting, latex agglutination (LA), immunochromatography Although it can be performed by a method or the like, it is preferable to use the ELISA method or the LA method. From the viewpoint of quantitativeness, it is preferable to use the sandwich method among the ELISA methods. In the sandwich method, a urine sample solution is added to a microtiter plate on which an anti-extracellular megalin antibody is immobilized to cause an antigen / antibody reaction, and then an enzyme-labeled anti-extracellular megalin antibody is added to perform the antigen / antibody reaction. After washing, reaction and color with the enzyme substrate are performed, and the absorbance is measured to detect megalin in urine, and the urinary megalin concentration can be calculated from the measured value. Alternatively, fluorescence may be measured after an antigen-antibody reaction using a fluorescently labeled anti-extracellular megalin antibody.

  The anti-extracellular region megalin antibody used in the immunological technique may be any antibody that can detect human megalin. The anti-extracellular region megalin antibody used in the present invention may be a known antibody or an antibody developed in the future. Although not particularly limited, the anti-extracellular region megalin antibody may be, for example, a monoclonal antibody or a polyclonal antibody, and includes a chimeric antibody, a humanized antibody, or a binding activity fragment thereof. These antibodies may be labeled with an enzyme or a fluorescent dye. Two or more types of anti-extracellular region megalin antibodies may be used. Two or more kinds of anti-extracellular region megalin antibodies are preferably antibodies that are used in the sandwich method and recognize different epitopes. For example, as an anti-extracellular region megalin antibody, an antibody that recognizes an epitope present in the region (LBD1) between the 26th amino acid and the 314th amino acid of the amino acid sequence shown in SEQ ID NO: 2 can be used.

  In the present invention, the urinary extracellular region megalin value may be the urinary extracellular region megalin concentration itself, but the urinary extracellular region megalin concentration is urinary components that are stably excreted in the urine. It may be a parameter corrected with a value relating to (component value in urine).

  As the urine component, urine creatinine is particularly preferable, and it is preferable to correct the urinary extracellular region megalin concentration by the urine creatinine concentration. The urinary creatinine concentration is considered to be almost constant for one individual regardless of the disease because the production of creatinine depends on the amount of muscle. In the examination of urinary components, in order to avoid urine volume error, a method of correcting the amount of the intended urinary component by the amount per 1 g of creatinine is generally used. It becomes possible to compare urinary components. A parameter obtained by correcting the urinary extracellular region megalin concentration by the urinary creatinine concentration is called urinary extracellular region megalin excretion (MEG / Cre), and can be calculated by the following equation.

<Formula> MEG / Cre: Urinary extracellular region megalin excretion (pmol / g) = 100 x Urinary extracellular region megalin concentration (pM) ÷ Urinary creatinine concentration (mg / dL)

  By measuring urinary extracellular region megalin, acute kidney injury can be detected or examined. That is, by measuring the urinary extracellular region megalin of a subject, it is possible to detect whether or not the subject suffers from acute kidney injury or to obtain data for judging whether or not the subject suffers from acute kidney injury. it can.

  When the amount of urinary extracellular region megalin excretion obtained by the test method of the present invention is higher than the reference value (Cut-Off value), it can be determined that it is acute kidney injury. According to the method of the present invention, it is possible to early detect acute kidney injury that is difficult to diagnose.

  Further, by measuring urinary extracellular region megalin, the risk of developing acute kidney injury can be determined, predicted, or evaluated. That is, by measuring a subject's urinary extracellular region megalin, the risk of the subject developing acute kidney injury can be determined, predicted, or evaluated, or determined, predicted, or Data for evaluation can be obtained. When the urinary extracellular region megalin excretion obtained by the test method of the present invention is higher than the reference value (Cut-Off value), it is determined that the risk of developing acute kidney injury is high, and is predicted or evaluated Can do.

  In addition, by measuring the urinary extracellular region megalin, the risk of developing acute kidney injury after cardiac surgery such as after open heart surgery or aortic replacement can be determined, predicted, or evaluated. Furthermore, postoperative prognosis such as postoperative hospitalization days and ICU entry days can be evaluated, and it is easy to make a schedule such as postoperative treatment plans. That is, in a subject undergoing the above cardiac surgery, the risk of the subject developing acute kidney injury after surgery by collecting the subject's urine before surgery and measuring the urinary extracellular region megalin. Or postoperative prognosis can be determined, predicted or evaluated, or data for determining, predicting or evaluating can be obtained. When the amount of urinary extracellular region megalin excretion obtained by the test method of the present invention is higher than the reference value (Cut-Off value), the risk of developing acute kidney injury is high, and the postoperative prognosis is also judged to be poor. Can be predicted, evaluated or evaluated. If the risk of developing acute kidney injury is high and the prognosis is poor, the subject's condition can be managed intensively after surgery, or the surgery may be discontinued.

  In addition, by measuring urinary extracellular megalin, the risk of developing acute kidney injury in patients admitted to the ICU or admitted to the general ward can be determined, predicted, or evaluated can do. That is, by collecting urine from ICU patients admitted to the ICU (intensive care unit) or patients admitted to the general ward and measuring urinary extracellular region megalin, the risk of developing acute kidney injury in the patient is increased. Data for determination, prediction, or evaluation can be obtained, or data for determination, prediction, or evaluation can be obtained. When the urinary extracellular region megalin excretion obtained by the test method of the present invention is higher than the reference value (Cut-Off value), it is determined that the risk of developing acute kidney injury is high, and is predicted or evaluated. Can do. There is a report that 35 to 65% of ICU inpatients and 5 to 20% of general ward inpatients develop acute kidney injury, and it is possible to prevent the onset by judging the risk by the method of the present invention. become.

  Although the reference value in the present invention can be appropriately set, the urinary extracellular region megalin value of a healthy person can be used. A healthy person is preferably a subject who is negative for other renal function markers, and examples of other renal function markers include estimated glomerular filtration rate (eGFR) and urine protein. More preferably, the urinary extracellular region megalin is detected for a plurality of healthy individuals, and the upper limit value of the 95% confidence interval of the urinary extracellular region megalin value is used as the reference value. The 95% confidence interval can be obtained by a known method. When the measurement value of a healthy person is normally distributed, it can be obtained by the following formula.

  95% confidence interval = average of extracellular region megalin value in normal urine ± t × standard deviation of extracellular region megalin value in normal human urine

  Note that t is a degree of freedom and varies depending on the number of healthy subjects, and therefore may be selected based on the t distribution table. In general, for a 95% confidence interval t is 1.96.

  On the other hand, if the normal region urinary extracellular megalin level is not normally distributed, the range that occupies 95% including the median is taken as the reference range, and the upper limit is the reference value for the extracellular megalin level in urine. To do.

  The present invention includes an anti-extracellular region megalin antibody for detecting urinary extracellular region megalin antibody, an acute kidney injury test reagent for testing acute kidney injury, and an acute kidney injury test containing the reagent A reagent kit is also included. The kit may contain a sample collection device, a sample processing solution, a reagent such as a chromogenic substrate, and may further contain a device necessary for the test.

  Examples of the present invention will be described below in more detail, but the present invention is not limited to these, and various applications are possible without departing from the technical idea of the present invention. It is.

(Example 1) Measurement of urinary extracellular region megalin excretion A urine of a fragment (extracellular region megalin) containing a human megalin extracellular region using a monoclonal antibody (anti-extracellular region megalin monoclonal antibody) against the human megalin extracellular region. Medium excretion was measured. The anti-extracellular region megalin monoclonal antibody is a mouse monoclonal antibody that recognizes an epitope present in the region (LBD1) between the 26th amino acid and the 314th amino acid of the amino acid sequence shown in SEQ ID NO: 2. Measurement was evaluated using anti-human megalin LBD1 monoclonal antibody A and anti-human megalin LBD1 monoclonal antibody B that recognize two different epitopes in LBD1. Using an anti-human megalin LBD1 monoclonal antibody A solid-phased microtiter plate and an ALP-labeled anti-human megalin LBD1 monoclonal antibody B, human megalin extracellular region-containing fragments in urine were measured. First, 90μL of urine and 2M Tris-HCl, 0.2M Ethylenediamine-N, N, N ', N'-tetraacetic acid (hereinafter Ethylenediamine-N, N, N', N'-tetraacetic acid is abbreviated as EDTA), 10 % (vol./vol.) Polyethylene Glycol Mono-p-isooctylphenyl Ether (hereinafter, Polyethylene Glycol Mono-p-isooctylphenyl Ether is referred to as Triton X-100), 10 μL of pH 8.0 solution, and 100 μL of the mixed solution are mixed. Anti-human megalin LBD1 monoclonal antibody A-immobilized microtiter plate (FluoroNunc ™ Module F16 Black-Maxisorp ™ Surface plate, manufactured by Nalge Nunc International) was added to the wells. Leave at 37 ° C for 1 hour, then remove the urine sample solution added to the wells by decantation, add TBS-T to the wells of the microtiter plate at 200 μL / well, and remove TBS-T by decantation. T was removed and washing was performed. This washing process was performed three times in total. Thereafter, an ALP-labeled anti-human megalin LBD1 monoclonal antibody B (0.5 ng / mL) solution was added at 100 μL / well. ALP-labeled anti-human megalin LBD1 monoclonal antibody B was prepared in a labeled antibody diluent. Leave at 37 ° C for 1 hour, then remove the ALP-labeled antibody solution added to the well by decantation, add TBS-T to the well of the microtiter plate at 200 μL / well, and decant TBS-T was removed and washed. This washing process was performed a total of 4 times. Thereafter, Assay Buffer was added to the well of the microtiter plate at 200 μL / well, and the Assay Buffer was removed by decantation and washed. This washing step was performed twice. Next, CDP-Star (registered trademark) Chemiluminescent Substrate for Alkaline Phosphatase Ready-to-Use (0.4 mM) with Emerald-II (trademark) Enhancer (ELISA-Light (trademark) System: Applied Biosystems) ALP As an enzyme reaction substrate solution, it was added at 100 μL / well and allowed to stand at 37 ° C. for 30 minutes in the dark. Immediately thereafter, the accumulated luminescence intensity for 1 second in this well was measured, and the measured value was used as an index for measurement evaluation of urinary extracellular region megalin. For measurement of chemiluminescence intensity, Microplate Luminometer Centro LB960 and MicroWin2000 software (Berthold) were used. Native human megalin extracted from the kidney was used as a standard product for the calibration curve. The urinary extracellular region megalin excretion amount obtained by correcting the urinary extracellular region megalin concentration with the urine creatinine concentration was calculated from the following equation.

<Formula> MEG / Cre: Urinary extracellular region megalin excretion (pmol / g) = 100 x Urinary extracellular region megalin concentration (pM) ÷ Urinary creatinine concentration (mg / dL)

  In addition, 205 pmol / g (urinary extracellular region megalin excretion amount) was used as a reference value (normal range) of the urinary extracellular region megalin excretion amount obtained from 56 healthy subjects. The 95% confidence interval was calculated from the normal distribution of urinary extracellular region megalin excretion in 56 healthy subjects, and the upper limit of this 95% confidence interval was 205 pmol / g (urinary extracellular region megalin excretion). Yes, this value was used as a reference value for the amount of urinary extracellular domain megalin excreted. Note that the reference value obtained this time may vary depending on changes in the measurement system platform and the standard setting method of the reference standard substance, and this value is a cut-off value that can be used permanently and permanently. It is not something to do. Therefore, 205pmol / g (extracellular urinary extracellular megalin excretion) is not a particularly limited value, but can be regarded as a consistently valid set reference value for the following verification. Can be judged from the verification contents described in the overall examples.

(Example 2) Clinical significance of urinary extracellular region megalin excretion in acute kidney injury The method of Example 1 was used to determine urinary extracellular region megalin excretion in 14 patients with acute kidney injury (AKI). Compared with 56 humans.

  FIG. 1 shows the result of comparison of urinary extracellular region megalin excretion between healthy persons and patients with acute kidney injury. The amount of urinary extracellular domain megalin excreted in patients with acute kidney injury was found to be significantly higher than that of healthy individuals (P <0.001). When the upper limit of the 95% confidence interval of the urinary extracellular region megalin excretion amount “MEG / Cre” obtained from urine obtained from healthy subjects is the reference value, the reference value is 205 pmol / g, and patients with acute kidney injury Of these, 64.3% showed a value higher than this reference value.

(Example 3) Clinical significance of urinary extracellular region megalin excretion in open heart surgery patients Concentration of urinary extracellular region megalin collected before open heart surgery in 54 patients who had undergone open heart surgery according to the method of Example 1 Was measured to determine the amount of urinary extracellular domain megalin excreted. After open heart surgery, we examined whether patients had acute kidney injury and 14 patients with acute kidney injury (AKI) and 40 patients with non-acute kidney injury (non AKI) The urinary extracellular region megalin excretion was compared. The result of the comparison is shown in FIG. It can be seen that urinary extracellular region megalin excretion is significantly higher (P <0.001) in patients with acute kidney injury after open heart surgery than in patients who have not.

(Example 4) Comparison with other renal disease markers According to the method of Example 1, the concentration of urinary extracellular region megalin collected before open heart surgery in 54 patients who had undergone open heart surgery was measured, and urinary extracellular Area megalin excretion was determined. In addition, tubule damage markers similar to urinary megalin, α1-microglobulin (AMG), β2-microglobulin (BMG), N-acetyl-β-D-glucosaminidase (NAG), Neutrophil gelatinase-associated lipocalin (N-gal) was measured. After performing open heart surgery, we investigated whether patients had acute kidney injury, 14 patients with acute kidney injury (AKI) and 40 patients with non-acute kidney injury (non AKI) Urinary extracellular region megalin excretion, AMG, BMG, NAG, N-gal were compared. The results of comparison of urinary extracellular region megalin excretion, AMG, BMG, NAG and N-gal are shown in FIGS. 2, 3, 4, 5 and 6, respectively. At this time, since AMG, BMG, NAG and N-gal shown above are urinary markers, correction was performed with urinary creatinine. Five types of urinary markers, including urinary extracellular domain megalin, showed significantly higher values (P <0.001) in patients with acute kidney injury after open heart surgery than those who did not. Only the amount of megalin excreted in the outer region.

  As described above, by measuring the urinary extracellular region megalin preoperatively by the test method of the present invention, it becomes possible to find a patient with postoperative acute kidney injury preoperatively. It has been reported that mortality is as high as about 50% when acute kidney injury is complicated by open heart surgery that requires management in the postoperative intensive care unit. In order to reduce this mortality rate, it is most effective to find patients with acute kidney injury after open heart surgery before surgery instead of during or after surgery. Excretion. Moreover, since the sample of the test | inspection method of this invention is urine, unlike the conventional method, it can test | inspect noninvasively and can reduce a patient's physical burden and is useful.

Claims (4)

  A mouse monoclonal that recognizes the region (LBD1) consisting of amino acids from the 26th amino acid to the 4424th amino acid of the amino acid sequence shown in SEQ ID NO: 2 for megalin containing the urinary extracellular region of the subject before cardiac surgery A test method for evaluating the risk of complication of acute kidney injury after cardiac surgery by measuring with an antibody.   The test method according to claim 1, wherein when the megalin value containing the urinary extracellular region is higher than the reference value, it is evaluated that the risk of complication of acute kidney injury is high. An anti-megalin antibody for detecting urinary megalin, comprising a mouse monoclonal antibody that recognizes a region (LBD1) consisting of amino acids 26 to 4424 of the amino acid sequence shown in SEQ ID NO: 2 A reagent for testing acute kidney injury, which is used in the testing method according to 1 or 2. A reagent for detecting urinary megalin using a mouse monoclonal antibody that recognizes a region (LBD1) consisting of amino acids 26 to 4424 of the amino acid sequence shown in SEQ ID NO: 2 as an anti-megalin antibody A reagent kit for testing acute kidney injury, which is used in the testing method according to claim 1 or 2 .

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