Project description:Background: Strategies to improve long term renal allograft survival have been directed to recipient dependent mechanisms of renal allograft injury. In contrast, no such efforts have been made to optimize organ quality in the donor. In order to get insight into the deleterious gene pathways expressed at different time points during deceased kidney transplantation, transcriptomics was performed on kidney biopsies from a large cohort of deceased kidney transplants. Methods: A total of 554 kidney biopsies were taken from living and deceased donor kidneys at donation, after cold ischemia and after reperfusion. Transcriptomics by means of whole genome micro-array analyses followed by functional pathway analyses was performed. Results: Oxidative stress and complement- and coagulation pathways were uncovered as potential pathways for intervention in deceased donors. No genes were found to be differentially expressed between donation and cold ischemia. After reperfusion, pathways related to oxidative stress, NOD-like signalling, MAPK, cytokine-cytokine receptor, complement- and-coagulation and chemokines were enriched in kidneys from deceased organ donors. Pathways related to prolonged and worsening deprivation of oxygen were associated with delayed graft function of DCD grafts. Conclusions: The present study reveals oxidative stress and enrichment of complement and coagulation pathways in deceased donor kidneys. Future intervention therapies to optimize donor organ quality and prolong allograft survival should target oxidative stress and innate immune activation in the donor.
Project description:The fate of transplanted kidneys is substantially influenced by the graft quality as transplantation of kidneys from elderly and expanded criteria deceased donors (ECD) is associated with higher occurrence of delayed graft function, rejection and inferior long term outcome. Little is known about early molecular fingerprints of these events in different donor categories. Borderline changes represent the most frequent histological finding early after kidney transplantation. Therefore, transcriptomic profiles of early case biopsies diagnosed as borderline changes were studied in ECD, standard criteria deceased donors (SCD) and living donor (LD) kidney transplantation using RNA microarray (Agilent SurePrintG3). The increased transcripts typical for ECD as compared to LD (n=437) showed enrichment of extracellular matrix (ECM) -receptor interaction (p=0.004) and complement and coagulation pathways (p=0.004) and GO terms related to platelet activation, blood coagulation, regulation of cell cycle, acute inflammatory response, wound healing or defense response (p<0.001). Gene annotation analysis of transcripts with increased expression in ECD grafts compared to SCD (n=244) showed the highest enrichment of inflammatory response (p=0.013), response to wounding (p=0.001) and defense response (p=0.005) and ECM-receptor interaction pathway (p=0.043). Comparative gene expression overlaps of ECD, SCD and LD using Venn’s diagrams found 62 up- and 16 down-regulated genes in ECD compared to both LD and SCD. Shared increased transcripts in ECD vs. both SCD and LD included, thrombospondin 2 (THBS2), angiopoietin-like 4 (ANGPTL4), collagens (COL6A3, COL1A1), chemokines CCL13 or interleukin IL11 and most significant down-regulated transcripts included proline rich 35 (PRR35) and fibroblast growth factor 9 (FGF9). Transcriptomic profile of higher inflammation and extracellular matrix remodeling in early borderline changes in the ECD kidney allografts suggest mechanisms how ischemia/reperfusion injury aggravates alloimmune response in the presence of chronic vascular changes.
Project description:Deceased kidney donation after brain death (DBD) is the main source of transplants, yet these grafts yield inferior transplant outcomes when compared to living donation. In brain death, cerebral injury contributes to systemic biological dysregulation, causing significant cellular stress in donor kidneys that adversely impacts the quality of grafts. Here, we hypothesized that proteolytic processes in DBD kidneys might lead to podocyte damage with subsequent development of post-transplant dysfunction. Using protein topography and migration analysis platform (PROTOMAP), we mapped degradation profiles of cytoskeletal proteins in DBD kidneys. Cytoskeletal proteolytic degradation was further studied by Immunoblotting on a separate cohort of deceased and living donor kidney biopsies. To investigate potential mechanism of kidney cytoskeletal protein degradation, in-vitro human podocytes and ex-vivo precision-cut human kidney slices were employed. We found novel proteolytic profiles of key podocyte cytoskeletal proteins in donor kidneys associated with suboptimal posttransplant function. These were unique to brain-death and were not observed in circulatory-death or living-donor kidneys. Talin-specific protein degradation in DBD kidneys indicated Calpain-1 activation may have a key role in proteolytic processes observed in the dysfunctional kidneys. Investigation of the underlying mechanism suggests that Transforming-Growth Factor-β (TGFβ) induces Calpain-1 activation, leading to brain-death specific podocyte degradation patterns and dysregulation of actin cytoskeleton; events that were prevented, in-vitro, by Calpain inhibition. Conclusion Our data demonstrate that podocyte protein degradation impacts the quality of DBD kidneys, propose a role of TGFβ mediated Calpain-1 proteolytic processing of cytoskeletal Talin-1, suggesting therapeutic opportunities to prevent kidney dysfunction.
Project description:The study aims to evaluate the efficacy of liver transplantation in the context of non-resectable colorectal liver metastasis. The primary endpoint is the overall survival in this group of patients while the secondary endpoint is the disease-free survival.
Patients included in this protocol will be evaluated either for whole or partial liver transplantation from deceased or living donors.
Type of different transplantations proposed are as follows:
1. Whole liver graft or partial liver (split) from a deceased donor
2. Partial liver graft retrieved from a deceased donor and orthotopically implanted after having performed a left hepatectomy in the recipient.
3. Partial liver graft retrieved from a deceased donor and heterotopically implanted if total hepatectomy can not be performed.
4. Partial liver graft retrieved from a living donor and orthotopically implanted after having performed total hepatectomy.
5. Partial liver graft retrieved from a living donor and orthotopically implanted after having after having performed a left hepatectomy in the recipient.
6. Partial liver graft retrieved from a living donor and heterotopically implanted if total hepatectomy can not be performed.
In cases 2-3-5-6 total hepatectomy of native liver can be secondarily performed after having achieved a proper graft hypertrophy in order to avoid a small for size syndrome
Project description:Transplanting renal allografts represents the major curative treatment of chronic renal failure. Despite recent advances in immunosuppressive therapy, long-term survival of allografts remains a major clinical problem. Kidney function depends in part on transport proteins such as MRP2 (ABCC2) which facilitates renal secretion of amphiphilic exogenous and endogenous compounds. Inherited variants of genes not related to the immune system have been shown to modify the outcome after renal transplantation. We investigated whether ABCC2 gene variants in the donor kidney affect renal graft function. A congenic rat model was established carrying a single nucleotide deletion in the ABCC2 gene. Renal cross transplantations were performed with wild type rats. Renal excretion of the MRP2 substrates bilirubin glucuronide and p-aminohippuric acid, but not morphine-6-glucuronide, was affected by the donor genotype. Moreover, proteomic analyses and transcriptional profiling revealed modified expression patterns indicative of increased oxidative stress in renal grafts carrying the mutated gene. In the clinical part our study, we assessed ABCC2 haplotypes in renal transplant patients and evaluated graft function. The 3563T>A gene polymorphism was significantly associated with delayed graft function. Together, both experimental and clinical data show that the ABCC2 genotype of the donor kidney affects renal graft function. Experiment Overall Design: Performed analyses of (6) wild-type and (6) MRP2 deficient kidneys that had been transplanted in wild-type recipients.
Project description:The biopsy samples obtained at implantation segregated in 2 distinct groups according to donor origin, with a cluster of 319 unique identified genes higher expressed in DD compared to LD kidneys, and 329 genes lower expressed (false discovery rate <5%). Using pathway analysis software a significant local renal overrepresentation of complement genes in DD implantation biopsies was identified. Complement gene expression in DD kidneys related both to donor death and cold ischemia duration, and was associated with a slower onset of renal allograft function. In post-transplantation protocol biopsies, there was a continued overexpression of complement genes, regardless of donor source. The local renal complement gene expression variability in post-transplantation biopsies correlated with renal graft function. This study demonstrates a significant and clinically relevant local overexpression of complement genes in DD kidneys at engraftment and continuous functionally important regulation of complement gene expression after transplantation, regardless of donor source. Targeted therapy interfering with complement activation is an attractive therapeutic target that deserves further investigation in solid organ transplantation. Keywords: time course, genomics gene expression
Project description:In deceased donor kidney transplantation, acute kidney injury (AKI) prioir to surgery is a major determinant of delayed graft function (DGF), but AKI is histologically silent and difficult to assess. We hypothesized that a molecular measurement of AKI would add power to conventional risk assessments to predict the early poor allograft function at first week post transplantation. We performed microarrays on implantation biopsies taken during reperfusion in 70 deceased donor kidneys from 53 donors. Early poor function was classified by two definitions on day 7 post-transplantation: serum creatinine greater than 265 umol/L (3 mg/dL) or the requirement for dialysis. Donor age and related risk scores (Irish, Schold, KDRI) associated with worse early function, as expected, but histologic features (glomerulosclerosis; pathology risk scores (Remuzzi, MAPI)) correlated with donor age but not with poor function. However, molecular AKI signal, previously defined in kidneys with early injury, was the best single predictor of poor allograft function. The combination of donor age and the AKI signal improved the prediction of poor function. In addition, asssessments of tissue quality particularly donor age, Banff ct, Irish and KDRI scores, showed negative correlative trend with late graft function, whereas the AKI signal did not. Thus donor age and the molecular AKI signal are the main predictors of early impaired function, but have little impact on survival.
Project description:Because of inherent differences between deceased donor (DD) and living donor (LD) liver grafts, we hypothesize that the molecular signatures will be unique, correlating with specific biologic pathways and clinical patterns. Following reperfusion, 579 genes in DD grafts and 1324 genes in LDs were differentially expressed (p<0.005). Many up-regulated LD genes were related to regeneration, biosynthesis and cell cycle, and a large number of down-regulated genes were linked to hepatic metabolism and energy pathways correlating with post-transplant clinical laboratory findings. There was significant up-regulation of inflammatory/immune genes in both DD and LD, each with a distinct pattern. Gene expression patterns of select genes associated with inflammation and regeneration in LD and DD grafts correlated with protein expression. Unique patterns of early gene expression are seen in LD and DD liver grafts, correlating with protein expression and clinical results, demonstrating distinct inflammatory profiles and significant down-regulation of metabolic pathways in LD grafts. Keywords: liver transplantation, live donor transplantation, liver regeneration, microarrays, mRNA expression, reperfusion injury
Project description:Donor organ shortage, growing waiting lists and organ discard rates are key problems in kidney transplantation. Donor organ quality is a critical factor determining post-transplant graft outcomes. However, organ quality is difficult to predict. Balancing the use of marginal donors without affecting outcomes is a main issue in the transplant field. The decision of acceptance of a kidney organ for transplantation is mainly based on donor organ biopsy findings, even though there are recognized limitations. The lack of better measures of organ quality at the time of transplantation as a predictor of performance graft outcome is a serious clinical challenge. Herein, we propose the use of a limited set of genes that captures intrinsic biology of kidney donor organs to improve available scoring systems. We studied gene expression in 192 deceased donor kidney biopsies and evaluated short-term outcomes which included delayed graft function and eGFR (high versus low) at 24 months for 168 kidney transplant recipients.