Unknown,Transcriptomics,Genomics,Proteomics

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Transcriptome analysis in human kidney to investigate whether fibrosis with inflammation at one year post transplant predicts transplant functional decline

ABSTRACT: We previously observed reduced graft survival for kidney transplants having interstitial fibrosis with subclinical inflammation, but not fibrosis alone, on 1-year protocol biopsy. The current study aimed to determine whether fibrosis with inflammation at 1 year is associated with renal functional decline in a low-risk transplant cohort and to characterize the nature of the inflammation. Subjects were living-donor, tacrolimus/mycophenolate-treated transplant recipients without overt risk factors for reduced graft survival (n=151). Transplants with normal histology (n=86) or fibrosis alone (n=45) on 1-year protocol biopsy had stable renal function between 1 and 5 years, while those having fibrosis with inflammation (n=20) had declining glomerular filtration rate and reduced graft survival. Immunohistochemistry confirmed increased interstitial T-cells and macrophages/dendritic cells in the fibrosis with inflammation group. Gene expression was performed on a subset of biopsies in each group and demonstrated increased expression of transcripts related to innate and cognate immunity in transplants having fibrosis with inflammation. Pathway- and pathological process-specific analyses of microarray profiles revealed that, in fibrosis with inflammation, over-expressed transcripts were enriched for potentially damaging immunological activities including Toll-like receptor signaling, antigen presentation/dendritic cell maturation, interferon gamma-inducible response, cytotoxic T lymphocyte-associated and acute rejection-associated genes. Thus, fibrosis with inflammation in 1-year protocol biopsies is associated with reduced graft survival and function and with a rejection-like gene expression signature even in recipients with no clinical risk for inferior outcome. Early interventions aimed at altering rejection-like inflammation may favor improved long-term KTx survival. We analyzed gene expression from a group of 65 renal transplant recipients. Patient groups were carefully selected to include patients on the same immunosuppression (Prograf-MMF-Pred), transplant type (LD), absence of over post-transplant complications (AR, BK, DGF). For each patient a 1 year protocol biopsy was examined by conventional histology and gene expression. By histology the patients were categorized as histologically normal (n=25, i/cg/ci=0), IF/TA (n=24, i/cg=0, ci>0) and IFTA+i (n=16, cg=0, i/ci>0). This dataset is part of the TransQST collection.

ORGANISM(S): Homo sapiens

SUBMITTER: Walter Park

PROVIDER: E-GEOD-22459 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Fibrosis with inflammation at one year predicts transplant functional decline.

Park Walter D WD Griffin Matthew D MD Cornell Lynn D LD Cosio Fernando G FG Stegall Mark D MD

Journal of the American Society of Nephrology : JASN 20100902 11

Lack of knowledge regarding specific causes for late loss of kidney transplants hampers improvements in long-term allograft survival. Kidney transplants with both interstitial fibrosis and subclinical inflammation but not fibrosis alone after 1 year have reduced survival. This study tested whether fibrosis with inflammation at 1 year associates with decline of renal function in a low-risk cohort and characterized the nature of the inflammation. We studied 151 living-donor, tacrolimus/mycophenola ...[more]

PMID: 20813870

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Project description:We study the global gene expression profiles of TGP patients with or without graft loss to determine if a clinical and/or gene expression profile can predict allograft survival. Transplant glomerulopathy (TGP) carries a poor prognosis and is associated with decreased allograft survival. In a large series of kidney transplant recipients, graft loss was observed in 38% of TGP patients at 5 years compared to 5% in patients without TGP. Among patients with TGP, predictors of poor outcome included C4d deposition in the peritubular capillaries, higher serum creatinine and proteinuria at diagnosis, the severity of interstitial fibrosis, and GBM duplication (higher Banff M-bM-^@M-^Xchronic glomerulopathy [cg]M-bM-^@M-^Y score), and the presence of DSA. However, the importance of microvascular inflammation determined by peritubular capillaritis (ptc) and glomerulitis (g) scores and the strength of DSA has not been explored thoroughly. We have recently reported the intragraft gene expression profiles of TGP patients, with or without DSA. However, the association between gene expression profiles of biopsies and the allograft survival has not been investigated. In this study, in addition to known clinical and demographic factors associated with poor outcomes in TGP, we specifically aimed to investigate if intragraft gene expression profiles by microarrays, microvascular inflammation scores, and the strength of DSA determined by mean fluorescence intensity (MFI) values could predict allograft loss in TGP patients. The study population was derived from renal allograft biopsies diagnosed with TGP at Montefiore Medical Center, Bronx, NY from January 2009 to December 2012. All biopsies were clinically indicated for elevated creatinine or proteinuria. A retrospective chart review was conducted to record clinical, demographic, immunological, and histopathological parameters and graft outcomes. Graft loss was defined as requiring dialysis and/or retransplantation during follow-up. Of the 525 patients who underwent clinically indicated transplant kidney biopsies, 52 patients (10%) had diagnosis of TGP. Median follow up time after the biopsy was 23 months (range, 1-46). Seventeen patients (32%) lost their allografts (defined by return to dialysis or re-transplantation) at a median time of 16 months (range, 1-44). A subgroup of patients who were enrolled in the IRB-approved M-bM-^@M-^\Immune Monitoring StudyM-bM-^@M-^] and had clinically indicated biopsy samples were included in the analysis. A total of 28 biopsy samples (8 graft loss and 20 functioning allograft) were used for gene expression profiling.

Project description:Introduction. Factors contributing to kidney transplant fibrosis remain incompletely understood—particularly in the absence of acute complications. Methods. Baseline and one-year surveillance biopsies from 15 uncomplicated living donor kidney transplants were subjected to microarray and quantitative RT-PCR (qRT-PCR) analyses in order to examine changes in gene expression patterns over time. Biopsy pairs were purposefully selected from allografts with no history of acute complications and were divided into those that were histologically normal (n = 7) and those that had developed subclinical interstitial fibrosis (n = 8) at 1 year. Results. Compared to the paired baseline specimens, expression levels of 3578 probesets were found altered in all the one-year biopsies studied. A large proportion of the upregulated genes in this transplant-associated profile were functionally linked with inflammation, immunity or response to injury. These included components of inflammation-related signaling pathways (integrin, interferon and TLR) as well as individual mediators of inflammatory and immune responses. An additional 2884 probesets demonstrated altered expression in fibrotic grafts only at 1 year. The gene products in this fibrosis-associated profile were also predominantly linked with inflammation and immune function, suggesting exaggerated inflammatory activity within the fibrotic grafts. qRT-PCR analyses confirmed the predicted expression patterns for selected transcripts from the microarray profiles. Conclusions. Transcriptional profiles of histologically normal living donor renal allografts indicate that there is ongoing injury response and inflammation at 1 year compared to the immediate post-transplant period. Subclinical development of interstitial fibrosis during the first post-transplant year is associated with additional upregulation of inflammation-related genes. Keywords: time course, comparative expression We analyzed gene expression from a group of 15 renal transplant patients. All patients had histologically normal time zero biopsy but while 7 remained histologically normal (TxNorm), 8 developed subclinical interstitial fibrosis (GIF/TA) by 1 year. Patient groups were carefully selected to include patients on the same immunosuppresion therapy, transplant type, biopsy histology and absence of overt post-transplant complications (acute rejection, BK, etc). This dataset is part of the TransQST collection.

Project description:Rationale: Interstitial fibrosis and tubular atrophy (IFTA) is found in ~25% of 1-year biopsies post-transplant(1, 2). It correlates with decreased graft survival when histological evidence of inflammation is present¬.(3-5) Identifying the etiology of IFTA is important because longterm graft survival has not changed as expected given improved therapies and a dramatically reduced incidence of acute rejection.(6-8) Methods: Gene expression profiles of 234 samples were obtained with matching clinical and outcome data (7 transplant centers). 81 IFTA samples were divided into subphenotypes by the degree of inflammation on histology: IFTA with acute rejection (AR), IFTA with inflammation and IFTA without inflammation. Samples with AR (n=54) and normally functioning transplants (TX; n=99) were used in comparisons. Conclusions: Gene expression profiling of all IFTA phenotypes were strongly enriched for cAR gene dysregulation pathways, including IFTA samples without histological evidence of inflammation. Thus, by molecular profiling we demonstrate that most IFTA samples have ongoing immune-mediated injury or chronic rejection that is more sensitively detected by gene expression profiling. We also found that the relative expression of AR-affiliated genes correlated with future graft loss in IFTA samples without inflammation. We conclude that undetected and/or undertreated immune rejection is leading to IFTA and graft failure. RNA was extracted from biopsy samples using the RNEasy kit (Qiagen), biotinylated cRNA prepared using Ambion MessageAmp Biotin II and hybridized to Affymetrix HG U133 Plus PM peg arrays (http://affymetrix.com/index.affx). Probe intensity data were log2–transformed and normalized using a custom-designed frozen Robust Multichip Average (fRMA). Low-variance and low signal probes were filtered according to industry standards, resulting in a filtered gene list with 17,564 transcripts. This dataset is part of the TransQST collection.

Project description:Background: Despite significant improvements in short-term kidney transplant survival, comparable increases in 5 and 10-year outcomes have not been achieved. Chronic allograft nephropathy (CAN) is a major cause of late graft loss. Toxic nephropathy and inadequate long-term immunosuppression are possible factors. We performed a randomized prospective trial comparing calcineurin inhibitor (CNI)-free to CNI-based immunosuppression to determine the impact on renal function, structure, and gene expression. Methods: Sixty-one kidney recipients received mycophenolate mofetil (MMF), and prednisone (P). Randomized patients received concentration-controlled sirolimus or cyclosporine. Two years post-transplant 55 patients underwent renal function studies, 48 (87%) underwent transplant biopsies; all classified by Banff scoring and 41 by DNA microarrays. Findings: Comparing sirolimus/MMF/P to cyclosporine/MMF/P at two years, there was a significantly lower serum creatinine (1.35 vs. 1.81 mg/dl; p=0.008), significantly higher Cockroft-Gault glomerular filtration rate (GFR) (80.4 vs. 63.4 cc/min; p=0.008), iothalamate GFR (60.6 vs. 49.2 cc/min; p= 0.018), and Banff 0 (normal) biopsies (66.6 vs. 20.8%; p=0.013). Regression analysis of calculated GFR’s from 1 to 36 months yielded a positive slope for sirolimus of 3.36 ml/min/year, and a negative slope for cyclosporine of –1.58 ml/min/year (p=0.008). Gene expression profiles of kidney biopsies with higher Banff CAN scores confirmed significant up regulation of genes responsible for immune/inflammation and fibrosis/tissue remodeling. Interpretation: At two years the sirolimus-treated patients have better renal transplant function, a diminished prevalence of CAN, and down regulated expression of genes responsible for the progression of CAN. All may provide for an alternative natural history with improved graft survival. Keywords = Cyclosporine Keywords = Sirolimus Keywords = Transplantation Keywords = DNA microarrays Keywords = calcineurin inhibitors Keywords: parallel sample. This dataset is part of the TransQST collection.

Dataset Information

Transcriptome analysis in human kidney to investigate whether fibrosis with inflammation at one year post transplant predicts transplant functional decline

Publications

Fibrosis with inflammation at one year predicts transplant functional decline.

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