Molecular profiling of acute and chronic rejections of renal allografts.
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ABSTRACT:
SUBMITTER: Petra H
PROVIDER: S-EPMC3834978 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundDimethylarginines are inhibitors of NO synthesis and are involved in the pathogenesis of vascular diseases. In this study, we ask the question if asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) levels change during fatal and reversible acute rejection, and contribute to the pathogenesis of chronic vasculopathy.MethodsThe Dark Agouti to Lewis rat strain combination was used to investigate fatal acute rejection. Fischer 344 kidneys were transplanted to Lewis rats to study reversible acute rejection episode and the process of chronic rejection. Isograft recipients and untreated Lewis rats were used as controls. l-arginine derivatives were determined by HPLC, and ADMA-metabolizing enzymes were studied by quantitative RT-PCR and western blotting.ResultsRenal transplantation transiently increased dimethylarginine levels independent of acute rejection. ADMA plasma levels did not importantly differ between recipients undergoing fatal or reversible acute rejection, whereas SDMA was even lower in recipients of Fisher 344 grafts. In comparison to isograft recipients, ADMA and SDMA levels were slightly elevated during reversible, but not during the process of chronic rejection. Increased dimethylarginine levels, however, did not block NO synthesis. Interestingly, protein methylation, but not ADMA degradation, was increased in allografts.ConclusionsOur data do not support the concept that renal allografts are protected from fatal rejection by dimethylarginines. Dimethylarginines may play a role in triggering chronic rejection, but a contribution to vascular remodelling itself is improbable. In contrast, differential arginine methylation of yet unknown proteins by PRMT1 may be involved in the pathogenesis of acute and chronic rejection.
| S-EPMC3006445 | biostudies-literature
Project description:Molecular testing represents a promising adjunct for the diagnosis of antibody-mediated rejection (AMR). Here, we apply a novel gene expression platform in sequential formalin-fixed paraffin-embedded samples from nonhuman primate (NHP) renal transplants. We analyzed 34 previously described gene transcripts related to AMR in humans in 197 archival NHP samples, including 102 from recipients that developed chronic AMR, 80 from recipients without AMR, and 15 normal native nephrectomies. Three endothelial genes (VWF, DARC, and CAV1), derived from 10-fold cross-validation receiver operating characteristic curve analysis, demonstrated excellent discrimination between AMR and non-AMR samples (area under the curve = 0.92). This three-gene set correlated with classic features of AMR, including glomerulitis, capillaritis, glomerulopathy, C4d deposition, and DSAs (r = 0.39-0.63, p < 0.001). Principal component analysis confirmed the association between three-gene set expression and AMR and highlighted the ambiguity of v lesions and ptc lesions between AMR and T cell-mediated rejection (TCMR). Elevated three-gene set expression corresponded with the development of immunopathological evidence of rejection and often preceded it. Many recipients demonstrated mixed AMR and TCMR, suggesting that this represents the natural pattern of rejection. These data provide NHP animal model validation of recent updates to the Banff classification including the assessment of molecular markers for diagnosing AMR.
| S-EPMC5658276 | biostudies-literature
Project description:BackgroundAcute pyelonephritis (APN) versus acute rejection (AR) is a frequently encountered diagnostic and therapeutic dilemma in kidney transplants. Variable culture results, overlapping histologic features, and persistent graft dysfunction despite antibiotics are frequently encountered. Therefore, we explored the utility of intragraft microRNA profiles to distinguish between allograft APN and AR.Materials and methodsBetween 2003 and 2011, we identified 49 patients with biopsy features of APN, within the first 2 years posttransplant. MicroRNA profiling was performed on 20 biopsies (normal kidney, n=4; unequivocal AR, n=5; features of APN, n=11).ResultsOnly 32% (16/49) of the patients had concomitant positive urine cultures at biopsy, and in 8 of 16 patients, colony count was less than 10 CFU/mL. In 14 of 49 patients, positive urine culture did not coincide with the biopsy, and in 19 of 49 patients, urine cultures were negative. On microRNA profiling, good clustering was seen among the normal kidneys and among AR biopsies. Among the 11 biopsies with features of APN, 4 biopsies showed good clustering with a pattern distinct from AR; (these patients recovered graft function with antibiotics); 7 of 11 biopsies showed heterogeneity in microRNA profiles and variable outcomes with antibiotic treatment. We identified a panel of 25 microRNAs showing statistical difference in expression between AR and APN. MiR-99b, miR-23b let-7b-5p, miR-30a, and miR-145 were validated using qPCR.ConclusionAllograft pyelonephritis can be a diagnostic and therapeutic challenge. A gestalt approach is required. In addition to histology and cultures, differential intragraft microRNA expression may prove helpful to distinguish APN from AR in renal allograft biopsies.
| S-EPMC4090250 | biostudies-literature
Project description:Increasing evidence accumulates on the central involvement of microRNAs (miRNAs) in disease pathophysiology. We identified distinctly deregulated miRNAs in human renal allograft biopsies from patients undergoing acute cellular rejection, antibody-mediated rejection (ABMR), and delayed graft function (DGF).Sixty-five posttransplantation kidney biopsy samples covering 41 cases with acute rejection (15 vascular rejection, 15 interstitial rejection, and 11 ABMR), 14 DGF cases, and 10 protocol biopsies serving as controls were analyzed using the Affymetrix GeneChip miRNA Array. Differentially regulated miRNAs were identified by Student's t test and Bonferroni correction. Target genes for the set of miRNAs were retrieved from miRTarBase (experimentally verified targets) as well as by applying the target prediction routines DIANAmT, miRanda, and Targetscan.Patients with acute cellular rejection, ABMR, and DGF discriminate from the control group (protocol biopsies) in unsupervised clustering of miRNA profiles, clearly identifying deregulated miRNAs in rejection and DGF. Angiogenesis, apoptosis, and transforming growth factor-? signaling were identified as relevant pathways in ischemic response following an integrative analysis of miRNA targets and mRNA expression profiles. Inflammation by chemokine and cytokine signaling, T-cell activation, and B-cell activation were identified as relevant in acute rejection accordingly.These data suggest that distinct miRNA signatures playing a role in specific biological pathways discriminate acute cellular and humoral rejection and DGF. This finding serves as valuable tool for a rational selection of diagnostic, prognostic, and potentially therapeutic molecular targets of posttransplantation events.
| S-EPMC3677100 | biostudies-literature
Project description: Not available
| S-DIXA-D-1171 | biostudies-other
Project description:Compromised renal function after renal allograft transplantation often results in anemia in the recipient. Molecular mechanisms leading to anemia during acute rejection are not fully understood; inadequate erythropoietin production and iron deficiency have been reported to be the main contributors. To increase our understanding of the molecular events underlying anemia in acute rejection, we analyzed the gene expression profiles of peripheral blood lymphocytes (PBL) from four pediatric renal allograft recipients with acute rejection and concurrent anemia, using DNA microarrays containing 9000 human cDNA clones (representing 7469 unique genes). In these anemic rejecting patients, an 'erythropoiesis cluster' of 11 down-regulated genes was identified, involved in hemoglobin transcription and synthesis, iron and folate binding and transport. Additionally, some alloimmune response genes were simultaneously down-regulated. An independent data set of 36 PBL samples, some with acute rejection and some with concurrence of acute rejection and anemia, were analyzed to support a possible association between acute rejection and anemia. In conclusion, analysis using DNA microarrays has identified a cluster of genes related to hemoglobin synthesis and/or erythropoeisis that was altered in kidneys with renal allograft rejection compared with normal kidneys. The possible relationship between alterations in the expression of this cluster, reduced renal function, the alloimmune process itself, and other influences on the renal transplant awaits further analysis. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Keywords: disease_state_design
2006-01-06 | GSE3976 | GEO
Project description:Many hypothesize that subtle inflammation and immune activity detected in the intraoperative period are linked to adverse postkidney transplant clinical outcomes. To this end, renal allografts were analyzed for expression of pro-inflammatory, inflammation-induced adhesion molecules, immune activation as well as anti-apoptotic genes expressed 15 min after vascular reperfusion (zero-hour) to determine whether this analysis can aid in predicting the occurrence of delayed graft function (DGF), acute rejection (AR), and the quality of graft function at 6 mo. Intraoperative biopsies were obtained from 75 consecutively performed renal allografts in which consent was obtained 15 min after vascular reperfusion. These biopsies were analyzed by quantitative real-time PCR for transcription of 15 select genes and by standard histopathology. Posttransplant clinical outcomes were also analyzed in respect to intraoperative transcriptional profiles and clinical parameters available at the time of transplantation. This study demonstrates that a limited and hypothesis-driven PCR-based transcriptional profile of the zero-hour kidney biopsy predicts posttransplant clinical outcomes including DGF, early AR, and the quality of renal function 6 mo posttransplantation. For some clinical endpoints, the combined use of molecular analysis and established clinical indicators available at the time of transplantation further enhances the quality of prognosis. The transcriptional profiling data provide absolutely essential data to the predictive models, particularly with respect to AR and renal function 6 mo posttransplantation.
| S-EPMC1350948 | biostudies-literature
Project description:The significance of borderline changes (BL) in kidney allograft biopsies is widely debated. We examined differences in gene expression patterns between early clinical biopsy tissue and 3-month protocol biopsy tissue, all of which had histological BL changes and identified specific molecular BL patterns associated with poor graft outcome. The expression profiles were analyzed in training set of patients and next data were validated in validation cohort using RT-qPCR. Using the Illumina microarray technology, we observed greater expression of immunity- and inflammation-related genes in tissues from early clinical biopsies compared to 3-month protocol biopsies with BL findings. In tissues with early clinically manifested BL changes, graft deterioration within 24 months due to chronic rejection was associated with increased activation of immune, defense, and inflammatory processes, specifically with higher donor age and expression of macrophage receptor CLEC5A. In the 3-month protocol biopsies with BL changes, graft dysfunction was associated with increased expression of fibrinogen complex transcripts. This study highlights the molecular differences between clinical and subclinical biopsies with similar histological findings. The data also support a recommendation for frequent patient monitoring, especially in those who received grafts from expanded criteria donors (ECDs).
2013-12-19 | GSE52694 | GEO
Project description:The significance of borderline changes (BL) in kidney allograft biopsies is widely debated. We examined differences in gene expression patterns between early clinical biopsy tissue and 3-month protocol biopsy tissue, all of which had histological BL changes and identified specific molecular BL patterns associated with poor graft outcome. The expression profiles were analyzed in training set of patients and next data were validated in validation cohort using RT-qPCR. Using the Illumina microarray technology, we observed greater expression of immunity- and inflammation-related genes in tissues from early clinical biopsies compared to 3-month protocol biopsies with BL findings. In tissues with early clinically manifested BL changes, graft deterioration within 24 months due to chronic rejection was associated with increased activation of immune, defense, and inflammatory processes, specifically with higher donor age and expression of macrophage receptor CLEC5A. In the 3-month protocol biopsies with BL changes, graft dysfunction was associated with increased expression of fibrinogen complex transcripts. This study highlights the molecular differences between clinical and subclinical biopsies with similar histological findings. The data also support a recommendation for frequent patient monitoring, especially in those who received grafts from expanded criteria donors (ECDs). The experiments were performed with total RNA derived from the renal graft biopsy samples of 28 different patients who had undergone a kidney transplantation. Only the patients with diagnosis of borderline changes early (M-bM-^IM-$2 months) or protocolar (3 months) were included in the study. RNA profiles of patients with stable and deteriorated graft function during 2 years after transplantation were compared. As microarray platform, Illumina HumanHT-12 v4.0 Expression BeadChips (Illumina) was used. The chip scanning was performed with a BeadStation 500 instrument (Illumina Inc), and the raw data were extracted with the BeadStudio Data Analysis Software (Illumina). The R software lumi package was used to further process the raw data. The quantile method was used for normalization.
2013-12-19 | E-GEOD-52694 | biostudies-arrayexpress
Project description:We previously demonstrated that donor treatment with inhaled hydrogen protects lung grafts from cold ischemia/reperfusion (I/R) injury during lung transplantation. To elucidate the mechanisms underlying hydrogen's protective effects, we conducted a gene array analysis to identify changes in gene expression associated with hydrogen treatment.Donor rats were exposed to mechanical ventilation with 98% oxygen and 2% nitrogen or 2% hydrogen for 3 h before harvest; lung grafts were stored for 4h in cold Perfadex. Affymetrix gene array analysis of mRNA transcripts was performed on the lung tissue prior to implantation.Pretreatment of donor lungs with hydrogen altered the expression of 229 genes represented on the array (182 upregulated; 47 downregulated). Hydrogen treatment induced several lung surfactant-related genes, ATP synthase genes and stress-response genes. The intracellular surfactant pool, tissue adenosine triphosphate (ATP) levels and heat shock protein 70 (HSP70) expression increased in the hydrogen-treated grafts. Hydrogen treatment also induced the transcription factors C/EBP? and C/EBP?, which are known regulators of surfactant-related genes.Donor ventilation with hydrogen significantly increases expression of surfactant-related molecules, ATP synthases and stress-response molecules in lung grafts. The induction of these molecules may underlie hydrogen's protective effects against I/R injury during transplantation.
| S-EPMC4007057 | biostudies-other