Protein levels of heme oxygenase-1 during reperfusion in human kidney transplants with delayed graft function

Introduction: Delayed graft function (DGF) as a consequence of ischemia reperfusion injury (IRI) is associated with a decrease in long-term allograft survival. Heme oxygenase-1 (HO-1) is a stress responsive gene that is highly expressed in multiple pathological processes. The aim of our study was to analyze whether HO-1 protein levels in human kidney transplants during IRI correlate with the incidence of DGF. Methods: Kidney biopsies were obtained from 27 kidney allografts at two time points: at the end of cold storage and shortly after reperfusion. Samples were analyzed for HO-1 protein levels by Western blot. Results: Heme oxygenase-1 protein levels were significantly higher in post-reperfusion biopsies (39.4 vs. 13.7 arbitrary units, p = 0.001). In pre-reperfusion biopsies no association was observed between HO-1 protein levels and DGF. In post-reperfusion biopsies, higher levels of HO-1 protein were measured in kidneys with DGF (53.7 vs. 36.2 arbitrary units, p = 0.064). DGF kidneys showed a significantly higher increase from pre- to post-reperfusion in HO-1 protein (42.0 vs. 18.7 arbitrary units, p = 0.025). Conclusion: Heme oxygenase-1 protein levels shortly after allograft reperfusion are closely related with initial graft function. Assessment thereof may be considered a valuable tool to predict DGF.