Influence of heme oxygenase-1 on microcirculation after kidney transplantation.

Background: Cytoprotective proteins, such as heme oxygenase-1 (HO-1), play a decisive role in ischemia-reperfusion injury during kidney transplantation. The aim of this study was to investigate the impact of heme oxygenase-1 on microcirculation and on ischemia-reperfusion injury in an isogenic kidney transplantation rat model.

Materials And Methods: Seventy male Lewis rats were distributed into three groups. In Group 1(control), the kidneys were only mobilized. In Groups 2 and 3, bilateral nephrectomy was performed, and a kidney from another Lewis rat was orthotopically transplanted on the left side. The donor animals in Group 3 received preconditioning with the HO-1 inductor hemin. 24 h after reperfusion graft function and morphology were examined. Microcirculation was investigated by in vivo microscopy of the renal surface 1 h after reperfusion.

Results: HO-1 preconditioning led to significantly lower serum creatinine and serum urea, as well as less histological damage and inducible nitric oxide synthase expression. Microcirculation was improved by a significant enlargement of the vascular diameter and an increase of the capillary flow.

Conclusions: Treatment with hemin improves microcirculation by induction of HO-1 and reduces ischemia-reperfusion injury after kidney transplantation. HO-1 induction was shown to be a promising approach in the preconditioning of donor kidneys.