Growth Differentiation Factor 15 Is Superior to Troponin I in the Evaluation of Kidney Transplant Candidates.

INTRODUCTION: Pretransplant cardiac troponin I (cTNI) has demonstrated its predicting value in survival after kidney transplant. Growth differentiation factor 15 (GDF-15) is a biomarker currently studied as a predictor of mortality and cardiovascular events (CVE) in different scenarios. The aim of this study was to compare the utility of these two biomarkers in the prediction of events after kidney transplant. METHODS: We included 359 kidney transplants performed in our center between 2005 and 2015. cTNI and GDF-15 were measured on stored serum samples obtained pretransplant. RESULTS: Median GDF-15 was 5,346.4 pg/mL, and cTNI was 5.6 ng/L. After follow-up, 77 (21.5%) patients died, and the incidence of cerebrovascular accident (CVA), acute coronary syndrome (ACS), and major adverse CVEs (MACE) was 6.38%, 12.68%, and 20.56%, respectively. Patients were stratified in tertiles according to GDF-15 and cTNT levels. By multivariate cox regression analysis including both biomarkers and different clinical characteristics, we found a significant relation between GDF-15 and mortality, CVAs, and MACE (highest tertile hazard ratio [HR] 2.2 95% confidence interval [CI] [1.2-4.1], p = 0.01, HR 9.7 CI 95% [2.2-43.1], p = 0.003 and HR 2.7 CI 95% [1.4-5.1], p = 0.002). On the contrary, posttransplant ACS was related to cTNI (highest cTNI tertile HR 3.2 CI 95% [1.5-7.3], p = 0.003). DISCUSSION: Our study indicates the potential utility of GDF-15 as a mortality and CVE predictor after kidney transplant and its superiority compared to cTNI. By contrast, probably due to its tissue specificity, cardiac troponin showed a stronger correlation with acute coronary events. Although more studies are needed to confirm our findings, these two molecules could be used in conjunction with other tools to predict adverse events after transplant and ideally find strategies to minimize them.

Long-term survival of renal transplantation in patients with lupus nephritis: experience from a single university centre.

OBJECTIVES: Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE). Unfortunately, 10-20% of patients with LN develop end-stage renal disease (ESRD), and renal transplantation may be a therapeutic option. However, concerns about LN recurrence after transplant have been reported. We aimed to assess long-term post-transplant graft and patient survival in LN compared to patients with non-autoimmune nephropathy (polycystic kidney disease - PCKD). METHODS: We carried out a single-centre retrospective study of all patients who underwent renal transplantation due to LN in a referral unit between 1980 and 2018. This cohort was compared with a group of PCKD patients. The main outcome variables were graft and patient survival for up to 20 years, and the time-course of serum creatinine and proteinuria in the first 5 years after transplantation. Cumulative survival rates were estimated by the Kaplan-Meier method and compared using the log-rank test. RESULTS: We included 53 patients: LN group (n=21) and PCKD group (n=32). Baseline clinical characteristics were similar in both groups, except age at transplantation (39.8±11.3 years in the LN group and 46.6±5.0 years in the PCKD group; p=0.004). No significant differences were found regarding graft (p=0.59) or patient survival (p=0.087) at 20 years of follow-up. CONCLUSIONS: Despite concerns about LN recurrence after renal transplantation, this study shows that this procedure might be a safe alternative therapy for ESRD related to SLE and may provide long-term survival.

Immunosuppression with Calcineurin Inhibitor after Renal Transplant Failure Inhibits Allosensitization.

Immunosuppression withdrawal after graft failure seems to favor sensitization. A high percentage of calculated panel-reactive antibody (cPRA) and the development of de novo donor specific antibodies (dnDSA) indicate human leukocyte antigen (HLA) sensitization and may hinder the option of retransplantation. There are no established protocols on the immunosuppressive treatment that should be maintained after transplant failure. A retrospective analysis including 77 patients who lost their first renal graft between 1 January 2006-31 December 2015 was performed. Two sera were selected per patient, one immediately prior to graft loss and another one after graft failure. cPRA was calculated by Single Antigen in all patients. It was possible to analyze the development of dnDSA in 73 patients. By multivariate logistic regression analysis, the absence of calcineurin inhibitor (CNI) at 6 months after graft failure was related to cPRA > 75% (OR 4.8, CI 95% 1.5-15.0, p = 0.006). The absence of calcineurin inhibitor (CNI) at 6 months after graft loss was significantly associated with dnDSA development (OR 23.2, CI 95% 5.3-100.6, p < 0.001). Our results suggest that the absence of CNI at the sixth month after graft loss is a risk factor for sensitization. Therefore, maintenance of an immunosuppressive regimen based on CNI after transplant failure should be considered when a new transplant is planned, since it seems to prevent HLA allosensitization.

Growth Differentiation Factor 15: A Biomarker with High Clinical Potential in the Evaluation of Kidney Transplant Candidates.

Kidney transplantation implies a significant improvement in patient survival. Nevertheless, early mortality after transplant remains high. Growth differentiation factor 15 (GDF-15) is a novel biomarker under study as a mortality predictor in multiple scenarios. The aim of this study is to assess the utility of GDF-15 to predict survival in kidney transplant candidates. For this purpose, 395 kidney transplant recipients with pretransplant stored serum samples were included. The median GDF-15 was 5331.3 (50.49-16242.3) pg/mL. After a mean of 90.6 ± 41.5 months of follow-up, 82 (20.8%) patients died. Patients with higher GDF-15 levels (high risk tertile) had a doubled risk of mortality after adjustment by clinical characteristics (p = 0.009). After adjustment by EPTS (Estimated Post Transplant Survival score) the association remained significant for medium hazards ratios (HR) 3.24 95%CI (1.2-8.8), p = 0.021 and high risk tertiles HR 4.3 95%CI (1.65-11.54), p = 0.003. GDF-15 improved the prognostic accuracy of EPTS at 1-year (ΔAUC = 0.09, p = 0.039) and 3-year mortality (ΔAUC = 0.11, p = 0.036). Our study suggests an independent association between higher GDF-15 levels and mortality after kidney transplant, adding accuracy to the EPTS score, an established risk prediction model currently used in kidney transplant candidates.