Endothelial dysfunction and vitamin D levels in kidney allograft recipients

There have been several studies demonstrating a relationship between vitamin D and cardiovascular disease. Vitamin D Deficiency/Insufficiency (D/I) is a common problem in chronic renal disease and also renal transplant recipients, however, there is a variation between the summer and winter periods. We investigated whether there is a relationship between vitamin D D/I and endothelial dysfunction in renal transplant recipients (RTR). We also evaluated vitamin D levels in summer and winter. Flowmediated dilatation (FMD), soluble endothelial protein receptor C (sEPRC) and soluble thrombomodulin (sTM) were chosen for markers of endothelial function. Firty-five patients were recruited to the study. Winter measurements were performed on March, summer measurements were performed in September. In the winter, methe an vitamin D level was 18.8±7.5, compared with 34.3±13.0 ng/ml in the summer period (p<0.0001). There were 38 (84%) and 20 (44%) patients in the winter and summer periods with vitamin D D/I, respectively. We did not find any significant association between vitamin D D/I and FMD, sTM or sEPCR in either period. While vitamin D D/I is a common finding during winter in RTR, it recovers in the summer. Moreover, vitamin D D/I seems not to be associated with endothelial dysfunction.