Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Gene Expression in Biopsies of Acute Rejection and Interstitial Fibrosis/Tubular Atrophy Reveals Highly Shared Mechanisms that Correlate with Worse Long-term Outcomes

ABSTRACT: 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.

ORGANISM(S): Homo sapiens

SUBMITTER: Sunil Kurian

PROVIDER: E-GEOD-76882 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Gene Expression in Biopsies of Acute Rejection and Interstitial Fibrosis/Tubular Atrophy Reveals Highly Shared Mechanisms That Correlate With Worse Long-Term Outcomes.

Modena B D BD Kurian S M SM Gaber L W LW Waalen J J Su A I AI Gelbart T T Mondala T S TS Head S R SR Papp S S Heilman R R Friedewald J J JJ Flechner S M SM Marsh C L CL Sung R S RS Shidban H H Chan L L Abecassis M M MM Salomon D R DR

American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons 20160315 7

Interstitial fibrosis and tubular atrophy (IFTA) is found in approximately 25% of 1-year biopsies posttransplant. It is known that IFTA correlates with decreased graft survival when histological evidence of inflammation is present. Identifying the mechanistic etiology of IFTA is important to understanding why long-term graft survival has not changed as expected despite improved immunosuppression and dramatically reduced rates of clinical acute rejection (AR) (Services UDoHaH. http://www.ustransp ...[more]

PMID: 26990570

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Project description:Immunosuppression is needed in HLA identical sibling renal transplantation. We conducted a tolerance trial in this patient cohort using Alemtuzumab induction, donor hematopoietic stem cells, tacrolimus/mycophenolate immunosuppression converted to sirolimus, planning complete drug withdrawal by 24 months post-transplantation. After an additional 12 months with no immunosuppression, normal biopsies and renal function, recipients were considered tolerant. Twenty recipients were enrolled. Of the first 10 (>36 months post-transplantation), 5 had immunosuppression successfully withdrawn for 16-36 months (tolerant), 2 had disease recurrence and 3 had subclinical rejection in protocol biopsies (non-tolerant). Microchimerism disappeared after 1 year, and CD4+CD25highCD127-FOXP3+ T cells and CD19+IgD/M+CD27- B cells increased to 5 years post-transplantation in both groups, whereas immune/inflammatory gene expression pathways in the peripheral blood and urine were differentially downregulated in tolerant compared to non-tolerant recipients. Therefore, in this HLA identical renal transplant tolerance trial, absent chimerism, Treg and Breg immunophenotypes were indistinguishable between tolerant and non-tolerant recipients, but global genomic changes indicating immunomodulation were observed only in tolerant recipients. A total of 46 PBMC samples representing blood draws from four time points in the first 9 recipients were processed for microarray analysis (The Scripps Research Institute, La Jolla, CA). The analyzed time points were: immediately pre-operatively in the absence of immunosuppression (n=9); post-operatively at 1 year (n=8, range 11-13 months); at 2 years (n=12, range 18-25 months); >3 years (n=17, range 32-48 months). (At year 2 and at > 3 years, repeated samples were obtained from individual subjects, and at one year, one subject had a technically unsatisfactory sample.) To discount the effects of immunosuppression on gene expression, microarray data were included on whole blood from 18 healthy human subjects (controls: GSE40586; NCBI Gene Expression Omnibus [GEO] repository).

Project description: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.

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Dataset Information

Gene Expression in Biopsies of Acute Rejection and Interstitial Fibrosis/Tubular Atrophy Reveals Highly Shared Mechanisms that Correlate with Worse Long-term Outcomes

Publications

Gene Expression in Biopsies of Acute Rejection and Interstitial Fibrosis/Tubular Atrophy Reveals Highly Shared Mechanisms That Correlate With Worse Long-Term Outcomes.

Similar Datasets

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