The fat mass and obesity related gene polymorphism influences the risk of rejection in heart transplant patients.

Heart transplantation is a relatively common treatment for end-stage heart failure. The major complication of heart transplantation is organ rejection. Epigenetic could play a role in the pathogenesis of organ rejection, and the FTO gene is a mediator of DNA methylation. We analyzed a tagging FTO SNP rs17817449 in both donor and recipient DNA obtained through 370 heart transplantations. Recipient FTO genotypes were not associated with either type of rejection or with the general increase in the risk of rejection. When compared with patients without a history of rejection, carriers of transplanted hearts with the FTO TT genotype exhibited a significantly increased risk (P = 0.02) of suffering from both types of rejection in comparison to carriers of hearts with at least one G allele (OR; 95% CI = 2.56; 1.15-5.69). Our results suggest that the donor, but not the recipient, FTO genotype could be a significant predictor of acute rejection in heart transplant patients.

Novel insights into pretransplant allosensitization in heart transplant recipients in the contemporary era of immunosuppression and rejection surveillance.

Solid-phase assays (SPA) have facilitated detection and definition of antibodies to human leukocyte antigens (HLA) and major histocompatibility complex class I chain-related antigen A (MICA). However, clinical consequences of pretransplant SPA results in heart transplantation have been studied insufficiently in the current era of immunosuppression and rejection surveillance. Pretransplant sera, panel-reactive antibodies (PRA), pretransplant crossmatch, and clinical data were retrospectively analyzed in 264 adult heart transplant recipients. The specificity of HLA and MICA antibodies and C1q-binding activity of donor-specific antibodies (DSA) were defined using SPA. Pretransplant HLA antibodies were detected in 57 (22%) individuals, in 28 individuals (11%); these antibodies were DSA after transplant. Preformed DSA and elevated peak PRA were independent predictors of pathologic AMR, which occurred in 19 individuals (7%). The increasing number of DSA and the cumulative mean fluorescence intensity of DSA were associated with AMR. C1q-binding assay was a suboptimal predictor of AMR in our cohort. Pretransplant allosensitization and MICA antibodies were related neither to impaired graft survival nor to other adverse clinical events during a median follow-up of 39 months. Identification of preformed DSA by SPA, in addition to PRA monitoring, may predict AMR in the contemporary era of heart transplantation.

Comparison of relative telomere length measured in aortic tissue and leukocytes in patients with end stage heart failure.

OBJECTIVES: Telomeres are repetitive non-coding DNA sequences on the ends of eukaryotic chromosomes. Relative leukocyte telomere length (LrTL) is considered to reflect biological ageing and fitness. Therefore, we examined whether LrTL would reflect rTL in aortic tissue (ArTL) and whether it could be used as a marker of biological heart age. DESIGN: We analysed telomere length in aortic and leukocyte samples from 73 heart recipients (63 males, 10 females; age 52.2±11.7 years). Relative telomere length was measured using a quantitative PCR-based method. RESULTS: Neither LrTL nor ArTL correlated significantly with the age of heart recipients. Mean ArTL was slightly shorter than LrTL (p=0.06) and there was a slight but significant inverse correlation between LrTL and ArTL (p=0.019). CONCLUSIONS: The age of patients with end stage heart failure was not associated with leukocyte or aortic telomere length. An inverse correlation between LrTL and ArTL suggests that LrTL is unlikely to be an important predictor of biological ageing in these patients.

Monitoring of plasma circulating donor DNA reflects cardiac graft injury: Report of two cases.

The current standard for graft rejection surveillance is endomyocardial biopsy (EMB), an invasive procedure with rare but potentially serious complications. Detection of circulating donor-derived cell-free DNA (ddcfDNA) is an option for noninvasive monitoring of graft injury and rejection. A 63-year-old man and a 65-year-old woman were monitored by EMB for allograft rejection. A total of 48 single-nucleotide polymorphisms with a minor allele frequency range of 0.4-0.5 were screened to distinguish donor and recipient DNA based on homozygosity, and digital droplet PCR was used to analyze ddcfDNA concentrations. Both subjects suffered rejection within the first 6 months after transplantation. The maximal ddcfDNA level of 270 copies (cp)/ml during EMB-confirmed acute cellular rejection (ACR; mild grade 1R/2, patient 1), and the maximal concentration of 1,846 cp/ml in the case of EMB-confirmed antibody-mediated rejection (AMR; grade 1+; patient 2), was detected. Individual monitoring of ddcfDNA dynamics from the 1st to the 6th month posttransplant reflected cardiac graft injury in patients suffering ACR or AMR, meaning that ddcfDNA may serve as a noninvasive biomarker.

Posttransplant Complications and Genetic Loci Involved in Telomere Maintenance in Heart Transplant Patients.

Reaching critically short telomeres induces cellular senescence and ultimately cell death. Cellular senescence contributes to the loss of tissue function. We aimed to determine the association between variants within genes involved in telomere length maintenance, posttransplant events, and aortic telomere length in heart transplant patients. DNA was isolated from paired aortic samples of 383 heart recipients (age 50.7 ± 11.9 years) and corresponding donors (age 38.7 ± 12.0 years). Variants within the TERC (rs12696304), TERF2IP (rs3784929 and rs8053257), and OBCF1 (rs4387287) genes were genotyped, and telomere length was measured using qPCR. We identified similar frequencies of genotypes in heart donors and recipients. Antibody-mediated rejection (AMR) was more common (p < 0.05) in carriers of at least one G allele within the TERF2IP locus (rs3784929). Chronic graft dysfunction (CGD) was associated with the TERC (rs12696304) GG donor genotype (p = 0.05). The genetic risk score did not determine posttransplant complication risk prediction. No associations between the analyzed polymorphisms and telomere length were detected in either donor or recipient DNA. In conclusion, possible associations between donor TERF2IP (rs3784929) and AMR and between TERC (rs12696304) and CGD were found. SNPs within the examined genes were not associated with telomere length in transplanted patients.

Association between aortic telomere length and cardiac post-transplant allograft function.

BACKGROUND: In patients having undergone orthotopic heart transplantation, a number of complications exist that are known to be connected to both telomerase activity and telomere length. The aim of this study was to determine how telomere length in aortic DNA correlates with the subsequent post-transplantation development of the patients. MATERIALS AND METHODS: Between 2005 and 2015, we collected aortic samples from 376 heart recipients (age 50.8 ±â€¯11.8 years) and 383 donors (age 38.6 ±â€¯12.2 years). Relative telomere length in aortic tissue DNA was determined using quantitative PCR. RESULTS: Shorter telomere length was detected in heart allograft recipients compared to donors (P < 0.0001). Patients suffering acute cellular rejection had significantly shorter telomere length (P < 0.01) than patients without rejection. Shorter telomere length was observed in patients with implanted mechanical circulatory support before heart transplantation (P < 0.03), as well as in subjects with cardiac allograft vasculopathy (P < 0.05). Overall survival time after heart transplantation was associated with shorter donor telomeres (P < 0.004). CONCLUSIONS: Telomere length differed between donors and recipients independent of the sex and age of the patients. Our findings suggest a potential new linkage between the aortic telomere length of recipients and post-heart transplant complications. Further studies focusing on epigenetic modifications and gene regulation involved in telomere maintenance in transplanted patients should verify our results.