The histopathologic classification for ANCA-associated GN distinguishes four classes on the basis of patterns of injury. In the original validation study, these classes were ordered by severity of ...kidney function loss as follows: focal, crescentic, mixed, and sclerotic. Subsequent validation studies disagreed on outcomes in the crescentic and mixed classes. This study, driven by the original investigators, provides several analyses in order to determine the current position of the histopathologic classification of ANCA-associated GN.
A validation study was performed with newly collected data from 145 patients from ten centers worldwide, including an analysis of interobserver agreement on the histopathologic evaluation of the kidney biopsies. This study also included a meta-analysis on previous validation studies and a validation of the recently proposed ANCA kidney risk score.
The validation study showed that kidney failure at 10-year follow-up was significantly different between the histopathologic classes (
<0.001). Kidney failure at 10-year follow-up was 14% in the crescentic class versus 20% in the mixed class (
=0.98). In the meta-analysis, no significant difference in kidney failure was also observed when crescentic class was compared with mixed class (relative risk, 1.15; 95% confidence interval, 0.94 to 1.41). When we applied the ANCA kidney risk score to our cohort, kidney survival at 3 years was 100%, 96%, and 77% in the low-, medium-, and high-risk groups, respectively (
<0.001). These survival percentages are higher compared with the percentages in the original study.
The crescentic and mixed classes seem to have a similar prognosis, also after adjusting for differences in patient populations, treatment, and interobserver agreement. However, at this stage, we are not inclined to merge the crescentic and mixed classes because the reported confidence intervals do not exclude important differences in prognosis and because an important histopathologic distinction would be lost.
De novo
thrombotic microangiopathy (TMA) is associated with poor kidney graft survival, and as we previously described, it is a recipient driven process with suspected genetic background. Direct ...Sanger sequencing was performed in 90 KTR with
de novo
TMA and 90 corresponding donors on selected regions in
CFH, CD46, C3
, and
CFB
genes that involve variations with a functional effect or confer a risk for aHUS. Additionally, 37 recipients of paired kidneys who did not develop TMA were analyzed for the
MCPggaac
haplotype. Three-years death-censored graft survival was assessed using Kaplan-Meier and Cox regression models. The distribution of haplotypes in all groups was in the Hardy-Weinberg equilibrium and there was no clustering of haplotypes in any group. In the TMA group, we found that
MCPggaac
haplotype carriers were at a significantly higher risk of graft loss compared to individuals with the wild-type genotype. Worse 3-year death-censored graft survival was associated with longer cold ischemia time (HR 1.20, 95% CI 1.06, 1.36) and recipients’
MCPggaac
haplotype (HR 3.83, 95% CI 1.42, 10.4) in the multivariable Cox regression model. There was no association between donor haplotypes and kidney graft survival. Similarly, there was no effect of the
MCPggaac
haplotype on 3-year graft survival in recipients of paired kidneys without
de novo
TMA. Kidney transplant recipients carrying the
MCPggaac
haplotype with
de novo
TMA are at an increased risk of premature graft loss. These patients might benefit from therapeutic strategies based on complement inhibition.
We evaluated biomarkers related to kidney fibrosis for the outcome of patients with IgA nephropathy (IgAN). Clinical parameters (estimated glomerular filtration rate, hypertension, proteinuria) and ...histological findings were assessed in 134 patients with IgAN at the time of diagnosis and followed up prospectively (mean follow-up time, 56.5 months). We measured biomarkers of collagen and laminin turnover in serum and urine collected at the time of kidney biopsy using a novel enzyme-linked immunosorbent assay. Linear discriminant analysis and logistic regression models were used to predict the patient's kidney outcome. Five serum and urine biomarkers of laminin and collagen turnover (sLG1M, sPRO-C3, sPRO-C6, uPRO-C6/Cr, uC3M/Cr) could significantly differentiae IgAN patients with a worse prognosis. Clinical parameters (glomerular filtration rate (GFR), proteinuria) distinguished patients at risk of IgAN progression with a specificity of 87.3% and a sensitivity of 45.2% (area under the curve-AUC 0.751). The addition of the biomarkers significantly increased the prognostic ability with a specificity of 85.1% and a sensitivity of 73.3% (AUC 0.905). We have identified three serum (sLG1M, sPRO-C3, sPRO-C6) and two urinary markers (uPRO-C6/Cr, u-C3M /Cr) that significantly improve the prognostic ability of markers of kidney function to identify an IgAN patient's risk of progressing to ESKD.
The recurrence of IgA nephropathy (IgAN) after kidney transplantation occurs in 20-35% of patients. The main aim of this study is to evaluate risk factors affecting the course of IgAN after renal ...biopsy of native kidney and kidney transplant. We evaluated clinical parameters and histological findings at the time of biopsy of native kidney and after kidney transplantation in 313 patients with IgAN with a follow-up of up to 36 years. Using hierarchical clustering method, patients with graft failure (n=50) were divided into two groups based on the mean time from kidney transplant to graft failure (11.2
6.1 years). The time-to-graft failure corresponded well to the time from the renal biopsy of native kidney to end-stage renal disease (5.9
0.4 years). Body mass index, proteinuria, microscopic hematuria, histological evaluation of fibrosis, and crescents at the time of renal biopsy of native kidney were the main variables for the differentiation of the two groups. Higher age of kidney-transplant donor, histological recurrence of IgAN, antibody-mediated rejection, and the onset of microscopic hematuria and proteinuria within 1 year after kidney transplant were also associated with worse graft survival in multivariate Cox regression analysis.
Activity and chronicity of kidney involvement in ANCA-associated vasculitis (AAV) can be currently reliably evaluated only by kidney biopsy. In this study, we measured a panel of serum and urinary ...biomarkers collected at the time of kidney biopsy and hypothesized that they could reflect specific histopathological parameters in the biopsy and help to predict prognosis.
We examined a cohort of 45 patients with AAV and 10 healthy controls. Biomarker levels (DKK-3, CD163, EGF, PRO-C6 and C3M) were measured in this study by ELISA. Biopsies were scored with a scoring system for AAV (focal x crescentic x sclerotic x mixed class) and interstitial fibrosis was quantified.
Levels of urinary DKK-3, CD163, EGF, PRO-C6 and C3M significantly differed among biopsy classes in AAV, with urinary DKK-3 and PRO-C6 levels being highest in the sclerotic class and lowest in the focal class, urinary CD163 levels highest in the crescentic class and urinary C3M levels highest in the focal class. Moreover, the urinary biomarkers were able to discriminate focal biopsy class from the other classes. Urinary DKK-3, EGF, PRO-C6 and C3M levels measured at the time of biopsy were also significantly related to the extent of fibrosis and to the final kidney function at the end of follow-up.
This small pilot study suggests that selected urinary biomarkers of fibrosis and inflammation may reflect changes in the kidney biopsy and be prognostic of kidney outcome in patients with AAV.
The complement system activation and regulation have been linked to post-transplant pathologies including chronic antibody mediated rejection (cAMR) and the recurrence of IgA nephropathy (ReIgAN) but ...distinct mechanisms remain to be elucidated.
In this retrospective single center study, the outcome of kidney transplantation was studied in 150 patients with late histological diagnosis to be either cAMR or ReIgAN, 14 stable kidney grafts at 3 months and finally 11 patients with native kidney IgAN nephropathy. To study a role of complement cascade and regulation in cAMR and ReIgAN, the RNA was extracted from available frozen kidney biopsy samples and using RT-qPCR transcripts of 11 target genes along with clinical data were determined and compared with stable grafts at 3 months protocol biopsies or IgAN native kidney nephropathy. Immunohistologically, CD46 (MCP), and C5 proteins were stained in biopsies.
Interestingly, there were no differences in kidney graft survival between cAMR and ReIgAN since transplantation. cAMR was associated with significantly higher intragraft transcripts of
, and
as compared to ReIgAN (
< 0.05). When compared to normal stable grafts, cAMR grafts exhibited higher
, and
(
< 0.01). Moreover, ReIgAN was associated with the increase of
(
< 0.01), and
(
< 0.05) transcripts compared with native kidney IgAN. Rapid progression of cAMR (failure at 2 years after biopsy) was observed in patients with lower intrarenal CD55 expression (AUC 0.77, 78.6% sensitivity, and 72.7 specificity). There was highly significant association of several complement intrarenal transcripts and the degree of CKD regardless the diagnosis;
, and
expressions positively correlated with eGFR (for all
< 0.001). Neither the low mRNA transcripts nor the high mRNA transcripts biopsies were associated with distinct trend in MCP or C5 proteins staining.
The intrarenal complement system transcripts are upregulated in progressively deteriorated kidney allografts.
Kidney fibrosis is the hallmark of chronic kidney disease (CKD) and is characterized by an imbalanced extracellular matrix (ECM) remodeling. Collagen type III is one of the main ECM components of the ...interstitial matrix of the kidney. We hypothesized that measuring three biomarkers of collagen type III reflecting different aspects of this protein turnover (C3M, C3C, and PRO-C3) may provide different information about the fibrotic burden in patients with IgA nephropathy (IgAN). We examined a cohort of 134 patients with IgAN. The three collagen type III biomarkers were measured in serum (S) and in urine (U) samples taken on the same day before kidney biopsy was performed. Biopsies were evaluated for interstitial fibrosis and tubular atrophy, according to the Banff and MEST-C scores. S-PRO-C3 and S-C3C correlated with the degree of fibrosis in the biopsy, whereas U-C3M/Cr had an inverse correlation with fibrosis. U-C3M/Cr had the highest discrimination ability for advanced fibrosis, which was maintained after adjustment for the other collagen type III biomarkers, proteinuria, and serum creatinine. The data presented in this study indicate that measuring the different fragments of the same ECM protein and in different matrices provides a variety of information regarding pathological kidney tissue alterations in patients with IgAN.
Abstract
Background and study aims
Circular ESD (CESD) is a treatment option for patients with extensive early esophageal cancer. Its major drawback is the development of a stricture. Stenting may ...represent an attractive prevention strategy. We designed an experimental study to assess the effect of stents covered with acellular biomatrix (AB) and a drug-eluting stent.
Materials and methods
Thirty-five 35 pigs underwent CESD and were randomized into six groups: G1 (control), G2 (SEMS), G3 (SEMS + AB), G4 (SEMS + AB + steroid-eluting layer), G5 (biodegradable stent BD), G6 (BD + AB). SEMS were placed alongside the post-CESD defect, fixed and removed after 21 days. The main outcomes were stricture development, severity, and histopathology.
Results
Pigs with BD stents (G5, 6) experienced severe inflammation and hypergranulation without biodegradation, therefore, these groups were closed prematurely. Significant strictures developed in 29 of 30 pigs (96.7 %). The most severe stricture developed in G2 and G4 (narrowest diameter (mm) 8.5 ± 3, 3 (G2) and 8.6 ± 2.1 (G4) vs. 17 ± 7.3 (G1) and 13.5 ± 8.3 (G3);
P
< 0.01. Signs of re-epithelization were present in 67 % and 71 % in G1 and G2 and in 100 % in G3 and G4. The most robust re-epithelization layer was present in G4. The inflammation was the most severe in G1 (mean score 2.3) and least severe in G4 (0.4).
Conclusions
Stenting did not effectively prevent development of post-CESD esophageal stricture. SEMS with AB resulted in improved re-epithelization and decreased stricture severity. Steroid-eluting SEMS suppressed inflammation. BD stents seem inappropriate for this indication.
Thrombotic microangiopathy (TMA) significantly affects kidney graft survival, but its pathophysiology remains poorly understood.
In this multicenter, retrospective, case-control paired study designed ...to control for donor-associated risks, we assessed the recipients' risk factors for de novo TMA development and its effects on graft survival. The study group consists of patients with TMA found in case biopsies from 2000 to 2019 (n = 93), and the control group consists of recipients of paired kidney grafts (n = 93). Graft follow-up was initiated at the time of TMA diagnosis and at the same time in the corresponding paired kidney graft.
The TMA group displayed higher peak panel-reactive antibodies, more frequent retransplantation status, and longer cold ischemia time in univariable analysis. In the multivariable regression model, longer cold ischemia times (odds ratio, 1.18; 95% confidence interval CI, 1.01-1.39;
= 0.043) and higher peak pretransplant panel-reactive antibodies (odds ratio, 1.03; 95% CI, 1.01-1.06;
= 0.005) were found to be associated with increased risk of de novo TMA. The risk of graft failure was higher in the TMA group at 5 y (hazard ratio HR, 3.99; 95% CI, 2.04-7.84;
< 0.0001). Concomitant rejection significantly affected graft prognosis at 5 y (HR, 6.36; 95% CI, 2.92-13.87;
< 0.001). De novo TMA associated with the active antibody-mediated rejection was associated with higher risk of graft failure at 5 y (HR, 3.43; 95% CI, 1.69-6.98;
< 0.001) compared with other TMA.
Longer cold ischemia and allosensitization play a role in de novo TMA development, whereas TMA as a part of active antibody-mediated rejection was associated with the highest risk for premature graft loss.
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