Homocysteine-dependent endothelial dysfunction induced by renal ischemia/ reperfusion injury

Background: Elevation of serum homocysteine is considered to contribute to endothelial dysfunc- tion, which is considered to be the initial event in vascular disease following renal transplantation. We sought to investigate whether an association exist- ed between serum homocysteine levels and endo- thelial dysfunction after renal ischemia/reperfusion (I/R) injury. Materials and methods: Acetylcholine (Ach)-induced endothelium-dependent and sodium nitroprusside (SNP)-induced endothelial-independent relaxation responses were determined in thoracic aortas from different I/R groups. A correlation analysis was per- formed between Ach responses and homocysteine levels. Results: Long-term I/R injury decreased the respons- es to acetylcholine and the pD 2 values of the con- centration response curves compared with controls. While vascular responses to SNP were unchanged among all groups. Homocysteine levels correlated with the pD 2 values of acetylcholine among control and I/R groups, indicating that the increase in homo- cysteine was associated with decreased sensitivity to acetylcholine. In short-term I/R rats, no associa- tion was observed between these parameters. Conclusion: These data suggest a possible link be- tween serum homocysteine and decreased vascular reactivity to endothelium-dependent relaxation in I/R aorta.