Α1-microglobulin Research Articles

Urinary Markers of Tubular Injury in Early Diabetic Nephropathy.

Diabetic nephropathy (DN) is a common and serious complication of diabetes associated with adverse outcomes of renal failure, cardiovascular disease, and premature mortality. Early and accurate identification of DN is therefore of critical importance to improve patient outcomes. Albuminuria, a marker of glomerular involvement in early renal damage, cannot always detect early DN. Thus, more sensitive and specific markers in addition to albuminuria are needed to predict the early onset and progression of DN. Tubular injury, as shown by the detection of tubular injury markers in the urine, is a critical component of the early course of DN. These urinary tubular markers may increase in diabetic patients, even before diagnosis of microalbuminuria representing early markers of normoalbuminuric DN. In this review we summarized some new and important urinary markers of tubular injury, such as neutrophil gelatinase associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid binding protein (L-FABP), N-acetyl-beta-glucosaminidase (NAG), alpha-1 microglobulin (A1M), beta 2-microglobulin (B2-M), and retinol binding protein (RBP) associated with early DN.

Urine alpha-1-microglobulin reliability in the diagnosis of pyelonephritis: a systematic review

Article type Systematic review article Introduction:Pyelonephritis is known as kidney inflammation due to bacterial infection which should be diagnosed and treated promptly. In this article, we decided to systematically review the diagnostic value and reliability of evaluating urine excretion low molecular weight protein alpha-1-microglobulin (A1M). Methods: PubMed and Scopus were searched for the relevant articles about the efficacy of urine alpha-1-micriglobulin assays in the diagnosis of pyelonephritis in children. The search strategy was microglobulin AND pyelonephritis. No language and date limitations were included in this review. Results: A total of 16 articles were retrieved from PubMed and 23 articles from Scopus. After studying the abstracts, only 5 articles were selected, which specifically studied the efficacy of alpha-1-micrglobulin in the diagnosis of pyelonephritis in children. Discussion: A1M is not an acute phase protein but its concentration alters in several clinical conditions. Conclusion: Evaluating the urine concentration of A1M is a noninvasive and cost effective strategy with the diagnostic capability for urinary tract disorders such as early recognition of tubular damages during pyelonephritis.

191 - Alpha-1-Microglobulin (A1M) Protects Kidney Epithelial Cells from Cellular, Mitochondrial and Molecular Damage Following Exposure to Heme and Hydroxyl Radicals

191 - Alpha-1-Microglobulin (A1M) Protects Kidney Epithelial Cells from Cellular, Mitochondrial and Molecular Damage Following Exposure to Heme and Hydroxyl Radicals

First trimester prediction of preeclampsia.

Preeclampsia (PE) is a serious pregnancy-related condition that causes severe maternal and fetal morbidity and mortality. Within the recent years, there has been an increasing focus in predicting PE at the end of the first trimester of pregnancy. In this review, literature published between 2011 and 2015 was evaluated. In a total of six biomarker algorithms, for first and early second trimester, the prediction of preeclampsia is discussed. In addition, one randomized clinical trial was included. Several algorithms were based on placental biomarkers such as pregnancy-associated plasma protein A (PAPP-A), placental growth factor (PLGF), and soluble FMS-like tyrosine kinase 1 (s-FLT-1). The algorithms containing these biomarkers showed a high prediction rate (PR) for early onset PE, ranging from 44 to 92% at 5% false positive rate (FPR). New biomarkers suggest an alternative model based on free HbF and the heme scavenger alpha-1-microglobulin (A1M) with a prediction rate of 69% at an FPR of 5%. Interestingly, this model performs well without uterine artery Doppler pulsatility index (UtAD-PI), which is an advantage particularly if the screening method were to be implemented in developing countries. The randomized clinical trial showed a clear reduction in early onset PE as well as reducing preterm PE if identified high-risk pregnancies were treated with low-dose aspirin. In conclusion, PE prediction is now possible through several prediction algorithms and prophylaxis is beneficial in high-risk cases.

Urinary biomarkers for early diabetic nephropathy in type 2 diabetic patients.

Diabetic nephropathy (DN) is a serious complication of diabetes associated with increased risk of mortality, and cardiovascular and renal outcomes. Diagnostic markers to detect DN at early stage are important as early intervention can slow loss of kidney function and improve patient outcomes. Urinary biomarkers may be elevated in diabetic patients even before the appearance of microalbuminuria, and can be used as useful marker for detecting nephropathy in patients with normoalbuminuria (early DN). We reviewed some new and important urinary biomarkers, such as: Neutrophil gelatinase associated lipocalin (NGAL), N-acetyl-beta-glucosaminidase (NAG), Cystatin C, alpha 1-microglobulin, immunoglobulin G or M, type IV collagen, nephrin, angiotensinogen and liver-type fatty acid–binding protein (L-FABP) associated with early DN in type 2 diabetic patients. Our search identified a total of 42 studies that have been published to date. Urinary levels of these biomarkers were elevated in type 2 diabetic patients compared with non-diabetic controls, including in patients who had no signs indicating nephropathy (without microalbuminuria), and showed positive correlation with albuminuria. Despite the promise of these new urinary biomarkers, further large, multicenter prospective studies are still needed to confirm their clinical utility as a screening tool for early type 2 DN in every day practice.

(143) - Donor- and Recipient-Related Predictors of Mortality After Heart Transplantation: Results From a Contemporary French National Cohort

s S61 Methods: 117 patients undergoing HTx at IKEM were prospectively enrolled. AKI was defined as an increase of serum creatinine level by ≥ 50% or worsening of renal function requiring renal replacement therapy (RRT) during 1st week postHTx. Serum Cystatin-C and urinary Neutrophil gelatinase-associated lipocalin (NGAL), alpha-1-microglobulin (A1M) or albumin were serially sampled. Results: 30 patients (25.6% of total) fulfilled the criteria of AKI. Preoperative renal function, demographics and comorbidities were similar between AKI and non-AKI groups. Cystatin-C displayed earliest and the most robust separation between AKI and non-AKI group, with significant difference present already 3 hours after surgery (figure left, arrow) and persisting on day 7 and 10. The increase in Cystatin-C preceded the serum creatinine elevation by 4 days. In univariate analysis, Cystatin-C> 1.6 mg/L at 3-hours after HTx predicted AKI with OR 5.1 (95%CI: 2.2-13) and in multivariate analysis (adjustment to presence of sepsis, bleeding or need of RVAD) with OR 4.4 (95% CI:1.7-12). Urinary NGAL raised significantly only on day 3 in AKI group (p= 0.003). Differences in ACR and A1M values between groups did not reach significance. Interestingly, elevated Cystatin-C (≥ 2.5mg/L at day 7) predicted also long-term mortality after HTx (figure right). Conclusion: Cystatin-C was the most useful for evaluation and prediction of AKI. Measurement of serum Cystatin-C in patients early after HTx (3h after surgery) may help to promptly identify the patients with high risk for renal complications. Elevated cystatin-C also predicts long-term outcome. (Grant NT/11269 5 and NT/ 11262-6 and Institutional support 00023001) ascending aortic diameter was also a predictor and may reflect the risks associated with an undersized allograft. The final predictor was total ischemic time emphasizing the need for improvements in allograft preservation and storage.

Comparaison des performances diagnostiques de deux tests de rupture prématurée des membranes (IGFBP-1/PAMG-1) en pratique clinique

Evaluate the two main immunochromatographic tests of premature rupture of membranes (PROM): Actimprom(®) based on the discovery of insulin-like growth factor binding protein-1 (IGFBP-1) and Amnisure(®) based on the discovery of placental alpha 1-microglobulin (PAMG -1). The comparison was made voluntarily in clinical practice and is interested in a population whose failure is not clean break. Prospective and comparative study performed on 2012, at the university hospital of Caen, in 85 patients with PROM suspected between 24SA and 36SA. The presence of blood, semen or vaginal infection has been notified. Frank rupture of membranes was an exclusion criterion. Actimprom(®) and Amnisure(®) were detected PROM with a specificity, sensitivity, PPV and NPV respectively 89.4% (CI 79.4-95.6%), 68.4% (CI 43.5-87.4%), 65% (CI 40.8-84.6%) and 90.8% (CI 81-96.5%). The results of both tests were not influenced by the presence of blood or inflammatory disease. Performance of these tests is probably related to the quality of the sample and the extraction step in bed of the patient. This work showed no significant difference between the two tests in terms of performance in the diagnosis of PROM. At present, there is no formally favor the use of one or the other.

The level of urinary α1 microglobulin excretion is a useful marker of peritubular capillaritis in antineutrophil cytoplasmic antibody associated vasculitis.

Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis affects small vessels in the kidney (i.e., arterioles, glomerular or peritubular capillaries, or venules). Although crescentic glomerulonephritis is a common histological finding, the incidence of peritubular capillaritis (PTC) or arteriolitis is unclear. Moreover, the laboratory data that reflect the degree of renal histological damage and distinguish between PTC and arteriolitis have not yet been clarified. We investigated laboratory data and histological findings from 11 patients diagnosed with ANCA-associated vasculitis (2 men and 9 women, mean age 70.3 ± 3.3 years) whose renal biopsies were performed between 2009 and 2014. All patients were positive for myeloperoxidase (MPO)-ANCA. PTC or arteriolitis was detected in six patients (54.5 %), respectively. The only significant positive relationship between laboratory data and histological findings observed was that between levels of urinary α1 microglobulin (u-α1MG) excretion and the percentage of tubular atrophy and interstitial fibrosis (r = 0.67, p = 0.035). No significant differences in laboratory data were found between patients with or without arteriolitis. However, the levels of u-α1MG excretion were significantly higher in patients with PTC than in those without PTC (75.2 ± 19.5 vs. 15.0 ± 3.6 mg/dl, p = 0.035). PTC or arteriolitis occurs at a high rate independently of crescentic glomerulonephritis in ANCA-associated vasculitis patients. The levels of u-α1MG excretion reflect the degrees of tubular atrophy and interstitial fibrosis. Moreover, high levels of u-α1MG excretion suggest that PTC is more likely than arteriolitis in ANCA-associated vasculitis patients.

Epidemiological survey of urinary Cadmium in Shengyang urban children

Objective To evaluate the body burden of Cadmium(Cd) in normal children from Shenyang city, and to analyze the effect of Cd on kidney.Furthermore, to investigate the influences of living factors on the level of Cd in children, so as to make recommendations for children's health. Methods The subjects was composed of 1 170 healthy children recruited from 0 to 17 years old by cluster random sampling method.They were divided into three groups(0-5 years old group, 6-11 years old group, 12-17 years old group). Questionnaires were used to obtain essential information about age, gender, weight, socioeconomic status, medication, and so on.Second morning urine samples were collected to make routine analyses, urinary Cd(Cdob), urine microalbumin(MALB) and α1-microglobulin(α1-MG). Results 1.A total of 1 070 children including 544 males and 526 females were enrolled.2.The concentration of Cdob increased with age, in agreement with the level of urinary Cd corrected by urine specific gravity(Cdsg). However, the level of Cd in urine corrected by urinary creatinine(Cdcr) presented the opposite status with the age increasing.3.Cdcr and urine MALB adjusted by urinary creatinin(MALBcr) revealed a positive correlation(rs=0.45, P<0.01).4.Pre-ference values for Cdob and Cdsg, Cdcr respectively were: 0-5 years old<0.56 μg/L, <0.83 μg/L and <2.17 μg/g Cr; 6-11 years old<0.65 μg/L, <1.01 μg/L and <1.23 μg/g Cr; 12-17 years old<0.74 μg/L, <1.15 μg/L and <1.25 μg/g Cr. Conclusions There is an age-dependent cumulative increases in Cdob.Although renal damage was not found in this study, the uptake of Cd should be reduced as much as possible and it is necessary to strengthen the follow-up study of Cdob in body burden. Key words: Urinary Cadmium; Epidemiological survey; Child

Characterization of heme binding to recombinant α1-microglobulin

Background: Alpha-1-microglobulin (A1M), a small lipocalin protein found in plasma and tissues, has been identified as a heme1 and radical scavenger that may participate in the mitigation of toxicities caused by degradation of hemoglobin. The objective of this work was to investigate heme interactions with A1M in vitro using various analytical techniques and to optimize analytical methodology suitable for rapid evaluation of the ligand binding properties of recombinant A1M versions.Methods: To examine heme binding properties of A1M we utilized UV/Vis absorption spectroscopy, visible circular dichroism (CD), catalase-like activity, migration shift electrophoresis, and surface plasmon resonance (SPR), which was specifically developed for the assessment of His-tagged A1M.Results: The results of this study confirm that A1M is a heme binding protein that can accommodate heme at more than one binding site and/or in coordination with different amino acid residues depending upon heme concentration and ligand-to-protein molar ratio. UV/Vis titration of A1M with heme revealed an unusually large bathochromic shift, up to 38 nm, observed for heme binding to a primary binding site. UV/Vis spectroscopy, visible CD and catalase-like activity suggested that heme is accommodated inside His-tagged (tgA1M) and tagless A1M (ntA1M) in a rather similar fashion although the His-tag is very likely involved into coordination with iron of the heme molecule. SPR data indicated kinetic rate constants and equilibrium binding constants with KD values in a μM range.Conclusions: This study provided experimental evidence of the A1M heme binding properties by aid of different techniques and suggested an analytical methodology for a rapid evaluation of ligand-binding properties of recombinant A1M versions, also suitable for other His-tagged proteins.

Effects of electro-acupuncture on endotoxic shock-induced acute kidney injury in rabbits: relationship with Keap1-Nrf2/ARE signaling pathway

Objective To evaluate the effects of electro-acupuncture (EA) at Zusanli and Shenshu acupoints on endotoxic shock-induced acute kidney injury (AKI) and the relationship with Keap1-Nrf2/ARE signaling pathway in rabbits.Methods Forty pathogen-free male New Zealand white rabbits,weighing 1.5-2.0 kg,were randomly divided into 4 groups randomly (n =10 each) using a random number table:control group (group C) ; endotoxic shock-induced AKI (group AKI) ; EA + endotoxin-induced AKI group (group EA) ; EA at non-acupoints + endotoxin-induced AKI group (group SEA).Endotoxic shock-induced AKI was induced with LPS 5 mg/kg (in 2 ml of normal saline) injected via the auricular vein.Electro-stimulation (2/15 Hz,0.2-0.6 ms,1-2 mA) of Zusanli and Shenshu acupoints was performed for 10 min once a day for 4 consecutive days,and the model was established on 5th day and then EA was continued until the animals were sacrificed in group EA.In group SEA,EA was performed at the points 5 mm lateral to the acupoints of Zusanli and Shenshu,and the other procedures were similar to those previously described in group EA.At 6 h of LPS,the urine was collected for determination of α1-microglobulin (α1-MG) concentrations.The animals were sacrificed and kidneys were removed for microscopic examination of the pathological changes which were also scored.Dry-wet weight method was used to measure water content in renal tissues.Nrf2 mRNA and HO-1 mRNA expression was detected using RT-PCR.The expression of Nrf2 total protein and nuclear protein and downstream HO-1 in renal tissues was determined by Western blot.Results Compared with group C,pathological scores,water content in renal tissues,and urinary α1-MG were significantly increased,and the expression of Nrf2 total protein and nuclear protein,HO-1,Nrf2 mRNA and HO-1 mRNA was up-regulated in AKI,EA and SEA groups.Compared with group EA,pathological scores,water content in renal tissues,and urinary α1-MG were significantly increased,and the expression of Nrf2 total protein and nuclear protein,HO-1,Nrf2 mRNA and HO-1 mRNA was down-regulated in AKI and SEA groups.There was no significant difference in each parameter between AKI and SEA groups.Conclusion EA at Zusanli and Shenshu can attenuate AKI induced by endotoxic shock in rabbits,and activation of keap1-Nrf2/ARE signaling pathway may be involved in the mechanism. Key words: Electric stimulation therapy ; POINT ST36 (ZUSANLI) ; POINT SL23 (SHENSHU) ; Endotoxemia ; Shock, septic ; Kidney failure, acute ; Nuclear factor erythroid 2-related factor2

P31 - A1M, an extravascular tissue cleaning and housekeeping protein: a possible drug candidate

Alpha-1-microglobulin (A1M) is a small protein found intra- and extracellularly in all tissues of vertebrates. The protein was discovered 40 years ago and its physiological role remained unknown for a long time. A series of recent publications have demonstrated that A1M is a vital part of tissue housekeeping. A strongly electronegative free thiol group forms the structural basis of heme-binding, reductase- and radical-trapping properties. A rapid flow of liver-produced A1M through blood and extravascular compartments ensures clearing of biological fluids from heme and free radicals and repair of oxidative lesions. After binding, both the radicals and A1M are electroneutral and therefore do not present any further oxidative stress to tissues. The biological cleaning cycle is completed by glomerular filtration, renal degradation and urinary excretion of A1M heavily modified by covalently linked radicals and heme-groups. Based on its role as a tissue housekeeping cleaning factor, A1M constitutes a potential therapeutic drug candidate in treatment or prophylaxis of diseases or conditions that are associated with pathological oxidative stress elements.

Therapeutic effect of maternal molecular hydrogen administration in a rat model of preeclampsia

s / Placenta 35 (2014) A1eA112 A78 Conclusion: A novel biomarker to specifically and reliably predict the risk for severe preeclampsia is successfully identified. Further investigations in larger cohorts including populations of other ethnic/genetic backgrounds are necessary. P2.52. THERAPEUTIC EFFECT OF MATERNAL MOLECULAR HYDROGEN ADMINISTRATION IN A RAT MODEL OF PREECLAMPSIA Takafumi Ushida, Yukio Mano, Tomomi Kotani Nagoya university graduate school of medicine, Nagoya city, Japan Objective: Preeclampsia is a pregnancy-specific condition characterized by new-onset hypertension and proteinuria. It is also occasionally related to fetal growth restriction. Some studies suggest that placental oxidative stress plays an important role in the pathogenesis of preeclampsia. Recently, molecular hydrogen (H2) is reported to prevent a variety of diseases associated with oxidative stress in model systems and in human. Here, we studied the efficacy of H2 using a rat model of preeclampsia. Methods:We used thewell-established reduced utero-placental perfusion pressure (RUPP) model of placental ischemia-induced hypertension in rat that mimics features of preeclampsia. RUPP was performed on day 14 of pregnancy, clips were placed around the aorta below the renal arteries and on both the left and right uterine arcade at the ovarian artery. The sham group underwent laparotomy on day 14 of pregnancy without RUPP procedure. Hydrogen-saturated water (HW) was orally administered ad libitum from day 12 to 19 of pregnancy. On day 19, mean arterial pressure (MAP) was measured via carotid catheters, and then fetus and placenta were collected by cesarean section. Results:MAP and urinary protein were significantly increased in the RUPP group compared with the sham group. HW treatment attenuated both MAP and urinary protein (sham 4.73, RUPP 8.14 and RUPP+HW 5.88mg/dL, respectively). RUPP fetuses and placentas were significantly smaller than those of sham group. In the RUPP+HW group, the decrease in fetal and placental weights was improved (fetal weight, sham 2.25, RUPP 1.79 and RUPP+HW 1.98g, respectively; placental weight, sham 0.417, 0.381 and 0.416g, respectively). Conclusion: The prophylactic administration of HWsignificantly attenuated features of preeclampsia. Moreover, fetal growth was also improved. These results suggest that maternal administration of HW could have a potential benefit for the prevention of preeclampsia as a novel intra-uterine therapy. P2.53. PREECLAMPSIA IN PREGNANCIES WITH AND WITHOUT DIABETES; THE ASSOCIATIONS WITH PLACENTAL WEIGHT. A POPULATION STUDY OF 655 842 PREGNANCIES Johanne Dypvik , Ellen Marie Strom-Roum , Camilla Haavaldsen , Lars Johan Vatten , Anne Eskild a,b Department of Obstetrics and Gynecology, Akerhus University Hospital, Lorenskog, Norway; b Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Public Health, Norwegian University of Science and Technology, Trondheim, Norway Objectives: To study whether placental weight in pregnancies with preeclampsia differs by maternal diabetes status? Methods: The study comprised all singleton deliveries in Norway from 1999 through 2010 (n 1⁄4 655 842). Data were obtained from the Medical Birth Registry of Norway. We used z-scores of placental weight to adjust for differences in gestational age at delivery between pregnancies, and we studied the distributions of placental weight z-scores in deciles (tenths) in preeclamptic pregnancies with and without diabetes and in normotensive pregnancies with and without diabetes. Results: In pregnancies with preeclampsia, the mean placental weight was much higher in diabetic pregnancies as compared to non-diabetic pregnancies. Thus, among pregnancies with preeclampsia, diabetic pregnancies were overrepresented in the highest decile of placental weight (28.8%) whereas preeclamptic pregnancies without diabetes were underrepresented in the highest decile of placental weight (9.8%). The enlargement of the placentas in preeclamptic pregnancies with diabetes was also pronounced in pregnancies with preterm delivery, and 30.1% were in the highest decile of placental weight as compared to 5.1% of the preeclamptic pregnancies without diabetes. Conclusion: In pregnancies with preeclampsia, the placenta was large when the mother had concomitant diabetes, whereas in preeclamptic pregnancies without diabetes the placenta was small and smaller than in normotensive pregnancies. This finding suggests that the placental role in preeclampsia may differ by maternal diabetes status. P2.54. ALPHA-1 MICROGLOBULIN AS A POTENTIAL THERAPEUTIC CANDIDATE FOR THE TREATMENT OF PREECLAMPSIA Lena Erlandsson , Ludivine Doridot , Aur elien Ducat , Johann Castille , Jean-Luc Vilotte , Lena Wester Rosenl€ of , Magnus Gram, Bo Akerstr€ om , Daniel Vaiman , Stefan Hansson a a Institution for Clinical Sciences in Lund, Lund University, Department of Obstetrics and Gynecology, Lund, Sweden,; b INSERM U1016, Institute Cochin, Paris, France; c INRA UMR1313, G en etique Animale et Biologie Int egrative, Jouy-en-Josas,

Alpha-1 microglobulin as a potential therapeutic candidate for the treatment of preeclampsia

Alpha-1 microglobulin as a potential therapeutic candidate for the treatment of preeclampsia

Fetal hemoglobin induces changes to the glomerular filtration rate in kidney that resembles symptoms observed during preeclampsia and was ameliorated by co-administration of alpha-1 microglobulin.

Fetal hemoglobin induces changes to the glomerular filtration rate in kidney that resembles symptoms observed during preeclampsia and was ameliorated by co-administration of alpha-1 microglobulin.

PD30-09 TRANSURETHRAL RESECTION OR INCISION OF THE PROSTATE AFTER RENAL TRANSPLANTATION: IS THERE A SAFE TIME FOR THE PROCEDURE?

improvements in graft survival following kidney transplantation. However, there are no non-invasive diagnostic parameters available that enable early and reliable detection of acute rejection. The objective of our study was to establish a urinary protein profile suitable to determine rejectionspecific changes following kidney transplantation and to predict early acute rejection at a postoperative stage. Furthermore, we focused on identification of candidate proteins for the use as biomarkers in clinical practice for diagnosis of acute rejection. METHODS: Urine samples of 116 kidney recipients were included. Rejection was proven by biopsy (n1⁄458) and stable transplant function was monitored for at least 2 years (n1⁄458). Postoperative urine samples were collected between 3rd and 10th day following transplantation. Urinary protein profiles were analyzed by SELDI-TOF-MS. Multiplex-Fluorescence-2DE and Peptide Mass Fingerprinting were used for identification of candidate proteins. Urinary concentration of candidate proteins was validated by ELISA. RESULTS: A protein signature including 4 masses differentiated acute rejection from stable transplant patients at the postoperative stage with 73% sensitivity and 88% specificity. Alpha-1-microglobulin (A1MG) and Haptoglobin (Hp) were identified as putative biomarkers for acute rejection. Protein levels were significantly higher in postoperative urine samples from patients with upcoming rejection than in stable transplant patients (A1MG: 29.13 mg/ml vs. 22.06 mg/ml, p1⁄40.001; Hp: 628.34 ng/ml vs. 248.57 ng/ml, p1⁄40.003). The combination of both proteins enabled the diagnosis of early rejection with 85% sensitivity and 80% specificity. CONCLUSIONS: Protein profiling using mass spectrometry is suitable for non-invasive detection of rejection-specific changes following kidney transplantation. A specific protein profile enables prediction of early acute allograft rejection in the immediate postoperative period. A1MG and Hp appear to be reliable rejection biomarkers. Further analyses have to show if early diagnosis is possible for patients with allograft rejection that occurs several month after transplantation by analyzing changes in urine protein pattern in regular intervals.

Urine protein profiling identified alpha-1-microglobulin and haptoglobin as biomarkers for early diagnosis of acute allograft rejection following kidney transplantation

Early diagnosis of acute rejection and effective immunosuppressive therapy lead to improvement in graft survival following kidney transplantation. In this study, we aimed to establish a urinary protein profile suitable to distinguish between patients with rejection and stable graft function and to predict acute rejection based on postoperatively collected urine samples. A further objective was to identify candidate proteins for the use as biomarkers in clinical practice. Urine samples of 116 kidney recipients were included. Rejection was proven by biopsy (n = 58), and stable transplant function was monitored for at least 2 years (n = 58). Postoperative urine samples were collected between 3rd and 10th day following transplantation. Urinary protein profiles were obtained by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. Protein identification and validation were performed using multiplex fluorescence 2DE, peptide mass fingerprinting and enzyme-linked immunosorbent assay. A protein profile including four mass peaks differentiated acute rejection from stable transplants at the time point of rejection and at the postoperative state with 73 % sensitivity and 88 % specificity. Alpha-1-microglobulin (A1MG) and Haptoglobin (Hp) were identified as putative rejection biomarkers. Protein levels were significantly higher in postoperative urine from patients with rejection (A1MG 29.13 vs. 22.06 μg/ml, p = 0.001; Hp 628.34 vs. 248.57 ng/ml, p = 0.003). The combination of both proteins enabled the diagnosis of early rejection with 85 % sensitivity and 80 % specificity. Protein profiling using mass spectrometry is suitable for noninvasive detection of rejection-specific changes following kidney transplantation. A specific protein profile enables the prediction of early acute allograft rejection in the immediate postoperative period. A1MG and Hp appear to be reliable rejection biomarkers.

Tubulointerstitial nephritis antigen expression in chronic kidney disease and its clinical significance

To explore tubulointerstitial nephritis antigen (TIN-ag) expression of chronic kidney disease (CKD) patients' renal tissue and the correlation to clinical phenotype. Through digital drawing lots, a total of 77 CKD patients from October 2012 to February 2013 at our department were randomly selected. All of them underwent biopsy. Based upon their pathological findings, they were divided into 2 groups of minimal change disease (MCD) and non-minimal change disease (NMCD). The stains of hematoxylin and eosin and Masson were used to observe renal pathological changes and immunofluorescence for detecting the TIN-ag expression of kidney tissue. The serum levels of creatinine, blood urea nitrogen, estimated glomerular filtration rate (eGFR), 24-hour urine output, 24-hour urine protein, α1-microglobulin, β2-microglobulin, pathological casts, N-acetyl-beta-glucosaminidase (NAG), specific gravity and other clinical parameters were monitored to examine their relationship between renal tissue TIN-ag expression. TIN-ag expression was distinct in renal tubular basement membrane of MCD patients while weak in primary focal segmental glomerulosclerosis (FSGS)(n = 16), IgA nephropathy (n = 23), MN (n = 14) and LN (n = 15) renal tissue. Immunofluorescence quantitative analysis showed that tubular TIN-ag fluorescence intensity of NMCD group was significantly lower than that of MCD group (4.84(3.02, 10.73) vs 20.79(8.19, 37.00), P < 0.01). In addition, TIN-ag expression in renal interstitial collagen area deposition of 0 grade group was higher than that of collagen area deposition 1-3 grades group (all P < 0.05). Serum α1-microglobulin and pathological urine cast, 24-hour urine protein of CKD patients were negatively correlated with kidney tubules TIN-ag expression (r = -0.312, -0.298, -0.214, all P < 0.05). Serum creatinine, blood urea nitrogen, serum β2-microglobulin and eGFR of CKD patients had no significant correlations with TIN-ag expression (P > 0.05). TIN-ag expression of CKD patients with lower expression levels of NAG was significantly higher than that of normal levels of NAG expression. TIN-ag expression of low urine specific gravity group was lower than that of normal urine specific gravity group (P < 0.05). TIN-ag expression of renal tissue tubule basement membrane in NMCD group is significantly lower than that in MCD group. TIN-ag expression is negatively correlated with renal tissue fibrosis. Expression of serum α1-microglobulin and concentrations of urinary pathology tube, 24-hour urine protein, NAG expression and urine specific gravity are negatively correlated with renal tissue TIN-ag expression in CKD patients.

Urinary biomarkers in assessing the nephrotoxic potential of gentamicin in solitary kidney patients after 7 days of therapy

Introduction: The solitary kidney (SK) may present increased vulnerability to nephrotoxicity because of adaptive phenomena. Aims: Assessing the vulnerability of the SK with urinary tract infections (UTI) to gentamicin by means of urinary biomarkers (N-acetyl-beta-D-glucosaminidase (NAG) and urinary alpha-1-microglobulin), as well as glomerular filtration rate (GFR). Methods: We studied 14 patients with SK with UTI (group A) (mean age 58.07 ± 13.61 years, mean duration of SK 13.55 ± 12.33 years) who were administered gentamicin for 7 days. Group B consisted by 17 patients with SK without any other associated renal pathology (average age 51.17 ± 9.39 years, average existence period of a single kidney 33.23 ± 21.73 years). We also included a third group (group C) represented by nine healthy individuals, with two kidneys. Results: Increased values of urinary NAG were found in group B as compared to group C and alpha-1 microglobulin in group A as compared to group B. During treatment with gentamicin, increased values of both NAG and alpha-1-microglobulin in group A were found on day 7 as compared to values before treatment (day 7 NAG = 18.99 ± 14.07 U/g creat versus day 0, NAG = 5.15 ± 6.54 U/g creat, p = 0.004; day 7 alpha-1-microglobulin = 20.88 ± 18.84 mg/g creat versus day 0, urinary alpha-1-microglobulin = 4.96 ± 6.57 mg/g creat, p = 0.003). No statistically significant alterations of GFR were noticed after 7 days of treatment. Conclusions: We found the nephrotoxic effects of gentamicin at tubular level, but not at glomerular level. The nephrotoxic potential of gentamicin in patients with a SK can be monitored by assessing urinary biomarkers during treatment of UTI.

Values of Alpha 1 Microglobulin Does Not Differ between Individuals with and without Family History of Balkan Endemic Nephropathy

Aim. The aim of this study was to compare urinary alpha 1 microglobulin (A1MG) in healthy individuals with and without family burden for Balkan endemic nephropathy (BEN) in an endemic village. Methods. Otherwise healthy inhabitants with microalbuminuria or proteinuria were divided into two groups: with (n = 24) and without (n = 32) family BEN burden and screened for urinary A1MG and A1MG/urine creatinine ratio. Results. Average value of urinary A1MG was 10.35 ± 7.01 mg/L in group with and 10.79 ± 8.27 mg/L in group without family history for BEN (NS, P = 0.87). A1MG was higher than 10 mg/L in eight (33.33%) inhabitants with family history and in 12 (37.5%) without (NS, P = 0.187). Average values of urinary A1MG/creatinine ratio were 1.30 ± 1.59 and 0.94 ± 0.78 in group with and group without family BEN history (NS, P = 0.39, resp.). Elevated values of this ratio were found in 13 (54.17%) inhabitants with and 14 (43.75%) without family history for BEN (NS, P = 0.415). Conclusion. We did not find statistically significant difference in the examined markers between healthy individuals with and without family burden for BEN. We concluded that these markers are not predictive of risk for BEN.