Expression data from kidney biopsies of liver disease patients
ABSTRACT: Glomerular abnormalities have been demonstrated in kidney biopsies of patient after orthotopic liver transplantation (OLT). We hypothesize that these changes exist prior to OLT and may play a role in the development of renal failure after OLT. We use gene expression microarrays to investigate the mechanism of kidney disease in patients listed for OLT. Gene expression profiles of biopsies of cirrhotic patients were compared with pre-implantation living donor biopsies. Glomerular abnormalities were seen in 92% of the biopsies, the most common being increase in mesangial matrix. Electron microscope showed effacement of podocytes (93%) and duplication (35%) and widening of glomerular basement membrane (45%). Gene Ontology analysis revealed significant up-regulation of genes implicated in immune response, including T-cell, leucocyte and platelet activation and differentiation. Pathogenesis-based transcripts analysis revealed significantly increased expression of cytotoxic T-cell, macrophage, B-cell, natural killer cell, and endothelial cell associated transcripts, indicating an ongoing inflammatory immune response. Eight patients with cirrhotic livers listed for transplantation were referred to the kidney transplant clinic at Montefiore Medical Center, Bronx, New York, for evaluation of renal dysfunction between April 2010 and March 2013. Patients consented prior to clinically indicated kidney biopsy for enrollment into the study. Information and lab results were collated for each patient including: age, sex, race, etiology of liver disease, history of diabetes mellitus (DM) and hypertension (HTN), metabolic profile, liver function tests, glycosylated hemoglobin (HgbA1c), C3 and C4 complement concentrations, antinuclear antibody titers and spot urine protein to creatinine ratio. Patients completed a 24-hr urine collection for protein and creatinine, which was used to assess proteinuria and creatinine clearance. eGFR was calculated using the Modified Diet of Renal Disease (MDRD) formula. Hematuria was defined as presence of any red cells in urine analysis. Proteinuria was defined as protein excretion of greater than 100mg in 24 hour. HTN and DM were defined by use of anti-hypertensive and insulin or oral hypoglycemic agents respectively in past or at time of kidney biopsy. Biopsies from cirrhotic patients were then compared to nine pre-implantation biopsies from living kidney donors. The de-identified patient clinical characteristics are provided in each sample records; For Hematuria, HTN, MM (mesangial matrix expansion), MC (mesangial cell increase), II (interstitial inflammation), podocyte, BM (basement membrane thickening), the value 0 and 1 represents 'ABSENT' and 'PRESENT', respectively. For C3 and C4, the value 0 and 1 represents NORMAL and LOW C3 (or C4) LEVELS, repectively. For TA (tubular atrophy), IF (interstital fibrosis), AS (arteiosclerosis), the value 0, 1, and 2 represents ABSENT, PRESENT MILD, and PRESENT MODERATE, respectively. For IgG, IgA, IgM, C, and EmPE, the values represent 1 (ABSENT), 1 (MILD STAINING), 2 (MODERATE), 3 (SEVERE), NA (NOT AVAILABLE), P (PENDING). For BMWId, BMd, and EDD, the values represent 0 (ABSENT), 1 (PRESENT), NA (NOT AVAILABLE), P (PENDING).
Project description:INTRODUCTION:Little is known about the association of urine metabolites with structural lesions in persons with diabetes. OBJECTIVES:We examined the relationship between 12 urine metabolites and kidney structure in American Indians with type 2 diabetes. METHODS:Data were from a 6-year clinical trial that assessed renoprotective efficacy of losartan, and included a kidney biopsy at the end of the treatment period. Metabolites were measured in urine samples collected within a median of 6.5 months before the research biopsy. Associations of the creatinine-adjusted urine metabolites with kidney structural variables were examined by Pearson's correlations and multivariable linear regression after adjustment for age, sex, diabetes duration, hemoglobin A1c, mean arterial pressure, glomerular filtration rate (iothalamate), and losartan treatment. RESULTS:Participants (n?=?62, mean age 45?±?10 years) had mean?±?standard deviation glomerular filtration rate of 137?±?50 ml/min and median (interquartile range) urine albumin:creatinine ratio of 34 (14-85) mg/g near the time of the biopsy. Urine aconitic and glycolic acids correlated positively with glomerular filtration surface density (partial r?=?0.29, P?=?0.030 and r?=?0.50, P?<?0.001) and total filtration surface per glomerulus (partial r?=?0.32, P?=?0.019 and r?=?0.43, P?=?0.001). 2-ethyl 3-OH propionate correlated positively with the percentage of fenestrated endothelium (partial r?=?0.32, P?=?0.019). Citric acid correlated negatively with mesangial fractional volume (partial r=-0.36, P?=?0.007), and homovanillic acid correlated negatively with podocyte foot process width (partial r=-0.31, P?=?0.022). CONCLUSIONS:Alterations of urine metabolites may associate with early glomerular lesions in diabetic kidney disease.
Project description:BACKGROUND:Immunoglobulin A nephropathy (IgAN) is a clinical and pathological syndrome with heterogenous manifestation and progression. Complement activation is involved in the disease. However, the clinical significance of C4 deposition in IgAN is obscure. METHODS:A multicenter retrospective study was conducted in biopsy-proven IgAN patients. Based on mesangial C4 deposition, patients were divided into two groups. The baseline clinical data and immunopathological phenotypes were compared. The composite endpoint was defined as eGFR decline greater than 50%, doubling of baseline serum creatinine, the occurrence of end-stage renal disease (ESRD). RESULTS:A total of 642 IgAN patients were recruited, with 41 patients showing mesangial C4 deposition. The mesangial C4 positive group showed lower serum albumin, higher proteinuria, and a higher rate of IgG, IgM, and C1q mesangial deposition. After a median follow-up of 43.18?months, 81 (12.62%) patients achieved the composite endpoint. The multivariate Cox regression models identified glomerular C4 deposition (hazard ratios [HR]?=?3.22, 95% confidence intervals [CI]?=?1.51-6.87, p?<?0.01), global sclerosis (G1 vs. G0, HR?=?1.90, 95%CI?=?1.02-3.52, p?=?0.04; G2 vs. G0, HR?=?3.72, 95%CI?=?1.98-7.00, p?<?0.01), male (HR?=?1.80, 95%CI?=?1.10-2.97, p?=?0.02), serum creatinine (HR?=?1.01, 95%CI?=?1.00-1.01, p?<?0.01), triglyceride (HR?=?1.17, 95%CI?=?1.01-1.35, p?=?0.04), proteinuria (HR?=?1.07, 95%CI?=?1.01-1.13, p?=?0.02), serum C3 level (HR?=?0.05, 95%CI?=?0.01-0.25, p?<?0.01), and serum C4 level (HR?=?99.59, 95%CI?=?8.69-1140.89, p?<?0.01) as independent risk factors for poor renal outcomes. CONCLUSIONS:Glomerular mesangial C4 deposition and global sclerosis are independent predictors for poor prognosis in IgAN patients.
Project description:Urine protein loss is common in dogs with chronic kidney disease (CKD).To evaluate new biomarkers of glomerular and tubulointerstitial (TI) damage compared with histology and as survival indicators in dogs with naturally occurring, proteinuric CKD.One hunderd and eighty dogs with naturally occurring kidney disease.Retrospective study using urine, serum, and renal biopsies from dogs with kidney disease, 91% of which had proteinuric CKD. Biomarkers were evaluated and correlated with pathologic renal damage, and significant associations, sensitivities, and specificities of biomarkers for renal disease type were determined.Fractional excretions of immunogloblin M (IgM_FE) and immunoglobulin G (IgG_FE) correlated most strongly with glomerular damage based on light microscopy (r = 0.58 and 0.56, respectively; P < .01). Serum creatinine (SCr) correlated most strongly with TI damage (r = 0.70, P < .01). Urine IgM/creatinine and urine NAG/creatinine had the highest sensitivity (75%) and specificity (78%) for detection of immune complex-mediated glomerulonephritis. Although individually most biomarkers were significantly associated with decreased survival time (P < .05), in a multivariate analysis, SCr, IgM_FE, and glomerular damage based on transmission electron microscopy (TEM) were the only biomarkers significantly associated with survival time (SCr: P = .001; IgM_FE: P = .008; TEM: P = .017).Novel urine biomarkers and FEs are useful for detection of glomerular and TI damage in dogs with proteinuric CKD and might predict specific disease types and survival.
Project description:Angiotensin receptor blockers are renoprotective in hypertensive azotemic patients with type 2 diabetes, but their efficacy in early diabetic kidney disease is uncertain. We performed a 6-year randomized clinical trial in 169 American Indians with type 2 diabetes and normoalbuminuria (albumin/creatinine ratio [ACR] <30 mg/g; n = 91) or microalbuminuria (ACR 30-299 mg/g; n = 78) at baseline. The primary outcome was decline in glomerular filtration rate (GFR) to ?60 mL/min or to half the baseline value in subjects who entered with GFR <120 mL/min. Another outcome was differences in glomerular structure at end of treatment. Subjects received 100 mg losartan or placebo daily. GFR was measured annually; 111 subjects underwent kidney biopsies. Only nine subjects reached the GFR outcome, and the unadjusted hazard ratio (losartan vs. placebo) was 0.50 (95% CI, 0.12-1.99). Differences in mesangial fractional volume were not estimated in the combined albuminuria groups because of an interaction with treatment assignment. In separate analyses, mesangial fractional volume was lower in subjects treated with losartan in the microalbuminuria group (18.8 vs. 25.6%; P = 0.02), but not in the normoalbuminuria group (19.6 vs. 17.8%; P = 0.86). Treatment with losartan may preserve some features of kidney structure in American Indians with type 2 diabetes and microalbuminuria.
Project description:Podocyte depletion is a common mechanism driving progression in glomerular diseases. Alport Syndrome glomerulopathy, caused by defective ?3?4?5 (IV) collagen heterotrimer production by podocytes, is associated with an increased rate of podocyte detachment detectable in urine and reduced glomerular podocyte number suggesting that defective podocyte adherence to the glomerular basement membrane might play a role in driving progression. Here a genetically phenotyped Alport Syndrome cohort of 95 individuals [urine study] and 41 archived biopsies [biopsy study] were used to test this hypothesis. Podocyte detachment rate (measured by podocin mRNA in urine pellets expressed either per creatinine or 24-hour excretion) was significantly increased 11-fold above control, and prior to a detectably increased proteinuria or microalbuminuria. In parallel, Alport Syndrome glomeruli lose an average 26 podocytes per year versus control glomeruli that lose 2.3 podocytes per year, an 11-fold difference corresponding to the increased urine podocyte detachment rate. Podocyte number per glomerulus in Alport Syndrome biopsies is projected to be normal at birth (558/glomerulus) but accelerated podocyte loss was projected to cause end-stage kidney disease by about 22 years. Biopsy data from two independent cohorts showed a similar estimated glomerular podocyte loss rate comparable to the measured 11-fold increase in podocyte detachment rate. Reduction in podocyte number and density in biopsies correlated with proteinuria, glomerulosclerosis, and reduced renal function. Thus, the podocyte detachment rate appears to be increased from birth in Alport Syndrome, drives the progression process, and could potentially help predict time to end-stage kidney disease and response to treatment.
Project description:X-linked Alport syndrome (XLAS), caused by mutations in the type IV collagen COL4A5 gene, accounts for approximately 80% of human Alport syndrome. Dogs with XLAS have a similar clinical progression. Prior studies in autosomal recessive Alport mice demonstrated early mesangial cell invasion as the source of laminin 211 in the glomerular basement membrane (GBM), leading to proinflammatory signaling. The objective of this study was to verify this process in XLAS dogs.XLAS dogs and WT littermates were monitored with serial clinicopathologic data and kidney biopsies. Biopsies were obtained at set milestones defined by the onset of microalbuminuria (MA), overt proteinuria, onset of azotemia, moderate azotemia, and euthanasia. Kidney biopsies were analyzed by histopathology, immunohistochemistry, and electron microscopy.XLAS dogs showed progressive decrease in renal function and progressive increase in interstitial fibrosis and glomerulosclerosis (based on light microscopy and immunostaining for fibronectin). The only identifiable structural abnormality at the time of microalbuminuria was ultrastructural evidence of mild segmental GBM multilamination, which was more extensive when overt proteinuria developed. Co-localization studies showed that mesangial laminin 211 and integrin ?8?1 accumulated in the GBM at the onset of overt proteinuria and coincided with ultrastructural evidence of mild cellular interpositioning, consistent with invasion of the capillary loops by mesangial cell processes.In a large animal model, the induction of mesangial filopodial invasion of the glomerular capillary loop leading to the irregular deposition of laminin 211 is an early initiating event in Alport glomerular pathology.
Project description:Environmental exposure to multiple metals is common. A number of metals cause nephrotoxicity with acute and/or chronic exposure. However, few epidemiologic studies have examined the impact of metal coexposure on kidney function. Therefore, the authors evaluated associations of antimony and thallium with kidney outcomes and assessed the impact of cadmium exposure on those associations in lead workers.Multiple linear regression was used to examine associations between ln-urine thallium, antimony and cadmium levels with serum creatinine- and cystatin-C-based glomerular filtration measures and ln-urine N-acetyl-?-D-glucosaminidase (NAG).In 684 participants, median urine thallium and antimony were 0.39 and 0.36 ?g/g creatinine, respectively. After adjustment for lead dose, urine creatinine and kidney risk factors, higher ln-urine thallium was associated with higher serum creatinine- and cystatin-C-based estimates of glomerular filtration rate; associations remained significant after adjustment for antimony and cadmium (regression coefficient for serum creatinine-based estimates of glomerular filtration rate =5.2 ml/min/1.73 m2; 95% CI =2.4 to 8.0). Antimony associations with kidney outcomes were attenuated by thallium and cadmium adjustment; thallium and antimony associations with NAG were attenuated by cadmium.Urine thallium levels were significantly associated with both serum creatinine- and cystatin-C-based glomerular filtration measures in a direction opposite that expected with nephrotoxicity. Given similarities to associations recently observed with cadmium, these results suggest that interpretation of urine metal values, at exposure levels currently present in the environment, may be more complex than previously appreciated. These results also support multiple metal analysis approaches to decrease the potential for inaccurate risk conclusions.
Project description:BACKGROUND:In type 1 diabetes, changes in the GFR and urine albumin-to-creatinine ratio (ACR) are related to changes in kidney structure that reflect disease progression. However, such changes have not been studied in type 2 diabetes. METHODS:Participants were American Indians with type 2 diabetes enrolled in a clinical trial of losartan versus placebo. We followed a subset who underwent kidney biopsy at the end of the 6-year trial, with annual measurements of GFR (by urinary clearance of iothalamate) and ACR. Participants had a second kidney biopsy after a mean follow-up of 9.3 years. We used quantitative morphometric analyses to evaluate both biopsy specimens. RESULTS:Baseline measures for 48 participants (12 men and 36 women, mean age 45.6 years) who completed the study included diabetes duration (14.6 years), GFR (156 ml/min), and ACR (15 mg/g). During follow-up, glomerular basement membrane (GBM) width, mesangial fractional volume, and ACR increased, and surface density of peripheral GBM and GFR decreased. After adjustment for sex, age, ACR, and each morphometric variable at baseline, an increase in ACR during follow-up was significantly associated with increases in GBM width, mesangial fractional volume, and mean glomerular volume, and a decrease in surface density of peripheral GBM. Decline in GFR was not associated with changes in these morphometric variables after additionally adjusting for baseline GFR. CONCLUSIONS:In American Indians with type 2 diabetes and preserved GFR at baseline, increasing ACR reflects the progression of earlier structural glomerular lesions, whereas early GFR decline may not accurately reflect such lesions.
Project description:BACKGROUND:Henoch-Schönlein purpura nephritis (HSPN) shares many similarities with IgA nephropathy. We aimed to analyze the predictive value of the International Study of Kidney Disease in Children (ISKDC) classification and the updated Oxford classification for IgA nephropathy in HSPN patients. METHODS:Data of 275 HSPN patients (aged≥14 years) were retrieved, and all of them underwent a renal biopsy. We re-classified the biopsies according to the ISKDC classification and the updated Oxford classification to analyze their correlations with clinical features and renal outcomes. The renal endpoints were defined as ≥30% reduction in baseline estimated glomerular filtration rate (eGFR) in 2 years, doubling of serum creatinine (Scr) or end stage renal disease. RESULTS:During follow-up period of 56(30,86) months, 30(10.9%) patients reached renal endpoints. Segmental sclerosis was the only pathological feature independently associated with renal endpoints (HR 4.086, 95%CI 1.111-15.026, P = 0.034). Tubular atrophy/ interstitial fibrosis was associated with eGFR and Scr levels, and its correlation with renal endpoints was found by univariate analysis. Endocapillary hypercellularity was associated with 24 h urine protein and is of prognostic value in univariate analysis. Mesangial hypercellularity was not associated with clinical features or renal endpoints. Crescents were associated with 24 h urine protein, Scr and eGFR levels, but both ISKDC and updated Oxford classifications of crescents were not associated with renal endpoints by multivariate analysis. CONCLUSIONS:The updated Oxford classification can help in disease management and renal outcome prediction of HSPN.
Project description:Chronic kidney disease (CKD) is a prevalent cause of morbidity and mortality worldwide. A hallmark of CKD progression is renal fibrosis characterized by excessive accumulation of extracellular matrix (ECM) proteins. In this study, we aimed to investigate the correlation of the urinary proteome classifier CKD273 and individual urinary peptides with the degree of fibrosis. In total, 42 kidney biopsies and urine samples were examined. The percentage of fibrosis per total tissue area was assessed in Masson trichrome stained kidney tissues. The urinary proteome was analysed by capillary electrophoresis coupled to mass spectrometry. CKD273 displayed a significant and positive correlation with the degree of fibrosis (Rho?=?0.430, P?=?0.0044), while the routinely used parameters (glomerular filtration rate, urine albumin-to-creatinine ratio and urine protein-to-creatinine ratio) did not (Rho?=?-0.222; -0.137; -0.070 and P?=?0.16; 0.39; 0.66, respectively). We identified seven fibrosis-associated peptides displaying a significant and negative correlation with the degree of fibrosis. All peptides were collagen fragments, suggesting that these may be causally related to the observed accumulation of ECM in the kidneys. CKD273 and specific peptides are significantly associated with kidney fibrosis; such an association could not be detected by other biomarkers for CKD. These non-invasive fibrosis-related biomarkers can potentially be implemented in future trials.