Relationship between hemorheology and endothelial dysfunction in renal transplant patients receiving calcineurin inhibitors

BACKGROUND: Calcineurin inhibitors, mainly cyclosporin A (CsA), are associated with endothelial dysfunction in renal transplant recipients (RTRs). Hemorheological disturbances including decreased erythrocyte deformability (ED), increased plasma viscosity and erythrocyte aggregation (EA) have also been reported in CsA-treated RTRs. The aim of this study was to investigate the relationship between hemorheological factors and endothelial dysfunction in CsA- and tacrolimus (Tc)-treated RTRs. METHODS: Thirty-one RTRs and 16 healthy subjects were recruited. The RTR group received either CsA (n = 16) or Tc (n = 15). Endothelial function was evaluated by flow-mediated dilation (FMD) of the brachial artery. ED and EA were measured with laser-assisted optical rotational cell analyzer, and plasma viscosity by a cone-plate viscometer. RESULTS: FMD of the CsA group was significantly lower than that of controls (6.3% ± 5.1% vs. 11.9% ± 5.6%, p = 0.024), whereas, there was no significant difference between the Tc group (8.8% ± 5.4%) and controls. At shear stresses ranging between 0.95 and 30 Pa, EDs of the CsA group were significantly lower compared with controls. In the Tc group, the decrease in ED was significant at shear stresses ranging between 0.53 and 5.33 Pa. ED indices did not correlate with FMD in any of the groups. CONCLUSIONS: The degree of endothelial dysfunction and reduction in ED were more remarkable in patients on CsA therapy. Hemorheological factors were not likely to be associated with endothelial dysfunction in RTRs.