Background: Endothelial dysfunction is a significant cause of vascular and end-organ damage after solid organ transplantation. The aim of this study was to compare endothelial function in healthy controls and in patients who received tacrolimus for immunosuppression after orthotopic liver transplantation (OLT).
Methods: Eight OLT patients and eight age- and BMI-matched healthy subjects were included in the study. Apart from hemodynamic parameters, enzymatic liver function, fasting plasma glucose levels, creatinine, cholesterol, nitric oxide and endothelin-1 levels were measured. Flow-mediated dilatation (FMD) in the brachial artery was determined by bi-mode ultrasound.
Results: Systolic and diastolic blood pressure and heart rate were higher in OLT recipients compared with the control group, but remained within normal limits. Blood results did not differ significantly between the groups. Circulating nitric oxide (152.2 +/- 29.7 vs. 180.6 +/- 40.1 micromol/L) and endothelin-1 (20.5 +/- 1.0 vs. 18.9 +/- 1.3 pmol/L) values were similar, and the FMD was normal in both groups (10.29 +/- 0.89 vs. 9.86 +/- 2.43% in controls and OLT recipients, respectively). There was a significant positive correlation between plasma tacrolimus levels after OLT and FMD (r = 0.72, p < 0.05).
Conclusion: As assessed by both laboratory and functional approaches, endothelial function was unaltered in patients taking tacrolimus after OLT. The positive correlation between tacrolimus plasma levels and FMD suggest that tacrolimus might have beneficial effects on endothelial function after OLT.