Project description:In clinical organ transplantation complete cessation of immunosuppressive therapy can be successfully accomplished in selected recipients providing a proof-of-principle that allograft tolerance is attainable in humans. The intra-graft molecular pathways associated with human allograft tolerance, however, have not been comprehensively studied before. In this study we analyzed sequential liver tissue samples collected from liver recipients enrolled in a prospective multicenter immunosuppressive withdrawal clinical trial. Tolerant and non-tolerant recipients differed in the intra-graft expression of genes involved in the regulation of iron homeostasis.These results point to a critical role of iron homeostasis in the regulation of intra-graft alloimmune responses in humans and provide a set of novel biomarkers to conduct drug-weaning trials in liver transplantation. The complete database comprised the expression measurements of 48766 probes in liver biopsies. The liver biopsy specimens available for the study were obtained: a) before immunosuppressive drugs were discontinued from tolerant (TOL, n=24) and non-tolerant (Non-TOL, n=29) recipients; b) at the time of rejection from non-tolerant recipients (Non TOL REJ, n=18); In addition, liver tissue samples were also collected from the following control patient groups: a) liver transplant recipients with chronic hepatitis due to recurrent hepatitis C virus infection (HEPC, n=12); b) liver transplant recipients with typical acute cellular rejection taking place during the immediate post-transplant period (REJ, n=9); c) liver transplant recipients under maintenance immunosuppression with normal liver function and normal liver histology 1 year after transplantation (CONT-Tx, n=8); and d) non-transplanted patients undergoing surgery for colorectal liver metastases (CONT, n=10).
Project description:The histological evaluation of liver via biopsy remains as the standard for the diagnosis of both acute cellular rejection (ACR) and recurrent hepatitis C (RHC) after liver transplantation. Nevertheless, it is often difficult to diagnose ACR in HCV-positive recipients because of common co-existing and overlapping morphological changes with RHC. The aim of the study was to identify potential target genes for ACR in recipients with RHC. We analyzed 22 liver biopsy samples obtained from 21 HCV-positive recipients. The clinicopathological diagnoses for the biopsies were ACR-predominant with superimposed RHC in 9 samples (ACR group) and RHC with no ACR (non-ACR group) in the remaining. We compared the transcriptional alterations between the two groups with oligonucleotide microarray and selected 2206 genes which were significantly modulated in ACR. Subsequently we analyzed the regulatory networks in ACR using Ingenuity Pathway Analysis, and focused on 5 genes (IFNAR1, IL-12RB2, NFATC3, BMP2, and CASP8) from the core network as the target genes for ACR. In conclusion, our results demonstrated that novel transcriptome patterns of ACR and concurrent RHC were present and distinct from recipients with only RHC, suggesting that gene expression profiling may have a role in the diagnosis of ACR in recipients with hepatitis C. Keywords: Gene identification in ACR with recurrent HCV infection Of 22 liver biopsy samples, 9 represented the clinicopathological diagnoses for ACR-predominant with superimposed RHC (ACR group) and 13 represented the clinicopathological diagnoses for RHC with no ACR (non-ACR group) .
Project description:The histological evaluation of liver via biopsy remains as the standard for the diagnosis of both acute cellular rejection (ACR) and recurrent hepatitis C (RHC) after liver transplantation. Nevertheless, it is often difficult to diagnose ACR in HCV-positive recipients because of common co-existing and overlapping morphological changes with RHC. The aim of the study was to identify potential target genes for ACR in recipients with RHC. We analyzed 22 liver biopsy samples obtained from 21 HCV-positive recipients. The clinicopathological diagnoses for the biopsies were ACR-predominant with superimposed RHC in 9 samples (ACR group) and RHC with no ACR (non-ACR group) in the remaining. We compared the transcriptional alterations between the two groups with oligonucleotide microarray and selected 2206 genes which were significantly modulated in ACR. Subsequently we analyzed the regulatory networks in ACR using Ingenuity Pathway Analysis, and focused on 5 genes (IFNAR1, IL-12RB2, NFATC3, BMP2, and CASP8) from the core network as the target genes for ACR. In conclusion, our results demonstrated that novel transcriptome patterns of ACR and concurrent RHC were present and distinct from recipients with only RHC, suggesting that gene expression profiling may have a role in the diagnosis of ACR in recipients with hepatitis C. Keywords: Gene identification in ACR with recurrent HCV infection
Project description:Recurrent hepatitis C virus (rHCV) is universal post-liver transplantation (LT), with accelerated fibrosis rates compared to non-transplanted patients. rHCV is associated with increased mortality and morbidity post-transplant and is a leading indication for re-transplantation. We hypothesized that miRNA expression profiles from liver grafts can distinguish severity of HCV recurrence and differentiate this from acute cellular rejection (ACR). Methods Using microarrays, we characterized global microRNA (miRNA) expression from patients with slow HCV fibrosis progression (F<2 Ishak), fast HCV fibrosis progression (FM-bM-^IM-%2 Ishak), ACR and non-HCV transplanted patients. Selected miRNA were analysed by quantitative PCR (qPCR) using both liver tissue and serum samples. Results We demonstrated changes in miRNA expression in patients with slow HCV fibrosis progression that were anti-fibrogenic, anti-angiogenic and anti-inflammatory in comparison to patients with fast HCV fibrosis progression. miRNA-146a, miRNA-19a, miRNA- 20a and miRNA-let-7e expression were increased in the slow HCV fibrosis progression group. In addition, comparison of patients with fast HCV progression against patients with ACR identified pro-fibrogenic pathways. qPCR analysis on liver tissue and serum confirmed the up-regulation of miRNAs in the slow HCV fibrosis progression group. Conclusion We demonstrate specific miRNA expression signatures that distinguish rate of progression of HCV recurrence and ACR post M-bM-^@M-^Sliver transplantation. Pathway analysis indicates that specific miRNA may play a regulatory role in these processes. The miRNAs identified may act as potential biomarkers for HCV recurrence post-LT and help distinguish between ACR and recurrent HCV. We compared 29 patients in total; 11 patients with slow HCV fibrosis progression, 9 patients with fast HCV fibrosis progression, 5 patients with acute cellular rejection and 4 HCV negative patients with normal liver histology that acted as controls. RNA was extracted from archived histology samples of the RG and NRG and miRNA expression was analysed using the affymetrix Genechip miRNA 2.0 assays.
Project description:Acute cellular rejection occurs frequently during the first few weeks following liver transplantation. During this period its molecular phenotype is confounded by pro-inflammatory events elicited by surgery, ischemia-reperfusion injury and early post-transplant complications. To unambiguously define the molecular profile associated with rejection we collected sequential biological specimens from liver transplant patients at least 3 years after transplantation who developed rejection while enrolled in trials of intentional immunosuppression withdrawal Transcriptomic RISET 2.0 chips were employed using portal blood vein from 37 liver trasplant patients.Two timepoints were selected: before immunosupressive weaning and rejection time point.
Project description:Liver transplantation is the only lifesaving therapy for patients with irreversible liver failure, and 30% of the recipients experience acute rejection in the first 12 months following transplantation. Acute rejection is diagnosed by core needle biopsy and noninvasive methods for predicting acute rejection could improve clinical care. MicroRNAs (miRNAs) are emerging as biomarkers of clinically significant events. We investigated whether circulating extracellular miRNA profiles in sera matched to liver allograft biopsies predict human liver allograft status. Small RNA sequencing and TaqMan low-density array analysis of RNA from biopsy matched sera identified that liver specific miR-122, and miRs -885, -210, -194, 193b, -192, -148a, -34a and -22 distinguish patients with acute rejection biopsies from those with biopsies without rejection features (false discovery rate of <0.15). We measured absolute levels of these informative 9 miRNAs using quantitative real-time PCR assays. Receiver-operating-characteristic (ROC) curve analysis of circulating levels of miRNA levels validated that all 9 miRNAs discriminate patients with acute rejection in their biopsies from those without rejection in their biopsies (P <0.01 to P<0.0001). A parsimonious diagnostic signature of miR-122 and miR-194 was diagnostic of acute rejection with a sensitivity of 79% (95% confidence interval [CI], 49% to 95%) and a specificity of 88% (95% CI, 64% to 99%) (area under the curve, 0.91; 95% CI, 0.81 to 1.00; P<0.001 by ROC curve analysis). Our findings suggest that a molecular signature of miR-122 and miR-194 in serum offers a noninvasive means of diagnosing acute rejection including mild forms in human liver allografts.
Project description:Acute cellular rejection is common after lung transplantation and is associated with an increased risk of early chronic rejection. We present combined single cell RNA and T cell receptor sequencing on recipient derived T cells obtained from the bronchoalveolar lavage of three lung transplant recipients with acute cellular rejection and compare them with T cells obtained from the same three patients after clinical treatment of rejection with high-dose, systemic glucocorticoids. At the time of acute cellular rejection, we find an oligoclonal expansion of cytotoxic CD8+ T cells, that all persist as tissue resident memory T cells following successful treatment. Persisting CD8+ allograft-resident T cells have reduced gene expression for cytotoxic mediators following therapy with glucocorticoids. This clonal expansion is discordant with circulating T cell clonal expansion at the time of rejection, suggesting in-situ expansion. These findings pose a potential biological mechanism linking acute cellular rejection to chronic allograft damage.
Project description:Acute rejection remains an important risk factor affecting the survival of recipients following transplantation. Bone marrow mesenchymal stem cells (BMMSCs) are used in the treatment of organ transplantation due to their immunomodulatory ability. BMMSCs were isolated from rat bone marrow and modified with the adenovirus for heme oxygenase 1 (HO-1) gene. Saline solution, BMMSCs or HO-1/BMMSCs were perfused into the donor liver in vitro using a normothermic machine perfusion (NMP) system, followed by liver transplantation. The liver grafts were collected at 7 days post-transplantation. Gene chip technology was used to detect differential gene expression.
Project description:Acute cellular rejection occurs frequently during the first few weeks following liver transplantation. During this period its molecular phenotype is confounded by pro-inflammatory events elicited by surgery, ischemia-reperfusion injury and early post-transplant complications. To unambiguously define the molecular profile associated with rejection we collected sequential biological specimens from liver transplant patients at least 3 years after transplantation who developed rejection while enrolled in trials of intentional immunosuppression withdrawal
Project description:Molecular Characterization of Acute Cellular Rejection Occurring during Intentional Immunosuppression Withdrawal in Liver Transplantation