Early non-invasive detection and prediction of graft function after kidney transplantation is essential since interventions might prevent further deterioration. The aim of this study was to analyze the dynamics and predictive value of four urinary biomarkers: kidney injury molecule-1 (KIM-1), heart-type fatty acid binding protein (H-FABP), N-acetyl-β-D-glucosaminidase (NAG), and neutrophil gelatinase-associated lipocalin (NGAL) in a living donor kidney transplantation (LDKT) cohort. Biomarkers were measured up to 9 days after the transplantation of 57 recipients participating in the VAPOR-1 trial. Dynamics of KIM-1, NAG, NGAL, and H-FABP significantly changed over the course of 9 days after transplantation. KIM-1 at day 1 and NAG at day 2 after transplantation were significant predictors for the estimated glomerular filtration rate (eGFR) at various timepoints after transplantation with a positive estimate (p < 0.05), whereas NGAL and NAG at day 1 after transplantation were negative significant predictors (p < 0.05). Multivariable analysis models for eGFR outcome improved after the addition of these biomarker levels. Several donor, recipient and transplantation factors significantly affected the baseline of urinary biomarkers. In conclusion, urinary biomarkers are of added value for the prediction of graft outcome, but influencing factors such as the timing of measurement and transplantation factors need to be considered.

Introduction Ischaemia reperfusion injury (IRI) is inevitable in kidney transplantation and negatively affects patient and graft outcomes. Anaesthetic conditioning (AC) refers to the use of anaesthetic agents to mitigate IRI. AC is particularly associated with volatile anaesthetic (VA) agents and to a lesser extent to intravenous agents like propofol. VA like sevoflurane interferes with many of the processes underlying IRI and exerts renal protective properties in various models of injury and inflammation. We hypothesise that a sevoflurane-based anaesthesia is able to induce AC and thereby reduce post-transplant renal injury, reflected in improved graft and patient outcome, compared with a propofol-based anaesthesia in transplant recipients of a deceased donor kidney. Methods and analysis Investigator-initiated, multicentre, randomised, controlled and prospective clinical trial with two parallel groups. The study will include 488 kidney transplant recipients from donation after brain death (DBD) or donation after circulatory death (DCD) donors. Participants are randomised in a 1:1 design to a sevoflurane (intervention) or propofol (control) group. The primary endpoint is the incidence of delayed graft function in recipients of DCD and DBD donor kidneys and/or 1-year biopsy-proven and treated acute rejection. Secondary endpoints include functional delayed graft function defined as failure of serum creatinine levels to decrease by at least 10% per day for three consecutive days; primary non-function is defined as a permanent lack of function of the allograft; length of hospital stay and postoperative complications of all kinds, estimated glomerular filtration rate at 1 week and 3 and 12 months calculated with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula; readmissions at 3 and 12 months, graft survival and all-cause mortality at 12 months. Ethics and dissemination The study is approved by the local ethical committees and national data security agencies. Results are expected to be published in 2025. Trial registration number NCT02727296.

Background: Ischemia–reperfusion injury (IRI) is a key contributor to graft dysfunction in kidney transplantation. Cell-free mitochondrial DNA (mtDNA) is increasingly recognized as a damage-associated molecular pattern (DAMP) and biomarker in IRI, but its prognostic role in living donor kidney transplantation (LDKT) remains unclear. Methods: This post hoc analysis of the VAPOR-1 study evaluated urinary mtDNA (UmtDNA) in 57 LDKT recipients. MtDNA levels (ND1, ND6, and D-loop) were measured at five early timepoints post-transplantation using qPCR. Associations between early UmtDNA and long-term graft function, defined by estimated glomerular filtration rate (eGFR) at 1, 12, and 24 months, were analyzed. Results: Higher UmtDNA levels in the first urine after reperfusion were significantly associated with improved eGFR at 12 months and a positive change in eGFR between month 1 and 24. These associations were not attributable to urine creatinine levels or mitochondrial copy number. Conclusions: In this LDKT cohort, elevated early UmtDNA may reflect a well-functioning graft capable of clearing systemic mtDNA rather than ongoing tubular injury. These findings suggest that the biological interpretation of mtDNA as a biomarker is context-dependent and call for careful reconsideration of its role in early transplant monitoring.

Ischemia reperfusion injury (IRI) is the primary cause of early complications in kidney transplantation and contributes to impaired graft function. Mitochondrial DNA (mtDNA), which is implicated in IRI-induced organ damage, has shown promise as a biomarker for assessing and predicting organ function, though studies have focused primarily on deceased donor transplantation. This post-hoc analysis of the VAPOR-1 study aimed to explore the presence, dynamics, and prognostic value of urinary mtDNA in a cohort of 57 living donor kidney transplantation (LDKT) recipients. Surprisingly, higher mtDNA gene levels in the first urine after transplantation were associated with higher estimated glomerular filtration rate (eGFR) at 12 as well as with an increase in eGFR between month 1 and month 24 after transplantation. These findings suggest that, contrary to prior assumptions of mtDNA as a damage marker, early urinary mtDNA levels may reflect graft function rather than injury. This study underscores the potential of urinary mtDNA as a prognostic tool for renal allograft function and advocates for a re-evaluation of the way early posttransplantation renal damage markers are interpreted in LDKT.