Carbon monoxide releasing molecules inhibit cell death resulting from renal transplantation related stress

Purpose: Organ cold storage and subsequent transplantation are associated with significant ischemia-reperfusion injury, leading to cell death, graft inflammation and decreased graft function. Materials and Methods: CORM-3s reduce oxidative stress and prevent inflammation in kidneys stored at 4C and subsequently transplanted. Graft survival and function are markedly improved compared to kidneys preserved and stored in University of Wisconsin solution alone. We determined whether CORM-3 has direct antiapoptotic effects on in vitro preparations of human HUVECs exposed to anoxic conditions. We also determined whether direct administration of CORM-3 to renal grafts before and/or after cold storage would prevent renal damage during the transplantation process. Results: CORM-3 supplementation led to a significantly increased frequency of live cells (mean ± SD 72.3% ± 1.9%, p <0.01), reduced apoptosis (14.9% ± 6.1%, p <0.01) and decreased mitochondrial transmembrane potential (40.2% ± 7.2%, p <0.05) in HUVECs exposed to 20 hours of cold storage compared to controls (11.6% ± 3.5%, 82.2% ± 2.3% and 78.2% ± 3.2%, respectively). In keeping with this antiapoptotic effect CORM-3 supplementation led to a mean 7.4 ± 2.1-fold up-regulation in Bcl-2 gene expression. CORM-3 supplementation in standard preservation solution was most beneficial at initial ischemic injury and before cold storage exposure. However, additional reflushing before vascular reperfusion showed an additive benefit to graft survival and function after transplantation. This was confirmed by decreased glomerular and tubular necrosis, and apoptosis in double flushed grafts. Conclusions: CORM-3 supplementation in standard University of Wisconsin solution has a significant impact on decreasing cellular and graft injury, and improving survival through its antiapoptotic effects, which are likely mediated through mitochondrial membrane stabilization.