The effect of immunosuppressive treatment on arterial stiffness and matrix Gla protein levels in renal transplant recipients

Introduction: Arterial stiffness is a risk marker for cardiovascular events. In this study we aimed to compare the effect on calcineurin inhibitors (CNI) and mammalian Target of Rapamycine inhibitors (mTORi) on arterial stiffness in renal transplant patients. Patients and methods: 81 renal transplant patients under CNI-based or mTORi-based protocol for at least 6 months were included in the study. Arterial stiffness was measured by using the SphygmoCor device (AtCor Medical, Sydney, Australia). Vitamin K-dependent, calcification inhibitor matrix Gla protein (MGP) concentrations were quantified by ELISA methods (Biomedica, Vienna, Austria). Results: 34 patients were on mTORi-based and 47 on CNI-based immunosuppression. Mean age was 37.9 +/- 10.8 (18 - 71) years and 45% were female. Age, gender, graft functions and follow-up period of the groups were similar. Augmentation index was 15.2 +/- 12.6% in CNI and 18.8 +/- 14.0% in mTORi groups (p > 0.05). There was no difference regarding carotid-femoral pulse wave velocity between groups. Arterial stiffness was positively correlated with age, total cholesterol, LDL cholesterol, mean arterial pressure (MAP) and proteinuria. MGP levels were higher in the mTORi group but were not predictors for carotid-femoral pulse wave velocity. Conclusion: Rather than specific immunosuppressive drug effects, conventional risk factors, blood pressure and proteinuria are the most important predictors for arterial stiffness in renal transplant patients.