Vascular endothelial function of sirolimus maintenance regimen in renal transplant recipients

Endothelial dysfunction is of vital importance as it may cause ischemia and dysfunction in various organs, especially the heart and kidneys. Despite this problem being well documented in patients with end-stage renal disease, there are insufficient data considering this issue to demand sirolimus use in renal transplantation. One potential cause of endothelial dysfunction in renal transplantation patients may be the use of the conventional protocols with cyclosporine [CsA]- versus sirolimus-based therapy. We studied 22 renal transplant recipients including on CsA (n = 14; group I, and sirolimus (n = 8; group II). Endothelial functions of the brachial artery were evaluated using high-resolution vascular ultrasound. Endothelium-dependent and-independent vasodilatations were assessed by sublingual nitroglycerine (NTG). Results are presented as percentage from baseline values. Significant endothelial dysfunction was noted among renal transplant patients treated with CsA. Endothelium-dependent vasodilatation was 3.6% ± 2.8% in group I and 14.5% ± 3.2% in group II (P < 0.002). The increase in brachial artery diameter after sublingual NTG measured 9.9% ± 4.7% versus 22.1% ± 5.9% in groups I and group II, respectively. This observation indicated that endothelial vasodilatation was preserved among patients on sirolimus but not CsA therapy. We concluded that endothelial vasodilatation is impaired in renal transplant recipients. Moreover, sirolimus seems to be more useful than CsA to overcome the compromised vasculature as observed in diabetic and elderly patients.