Longitudinal analysis of vascular function and biomarkers of metabolic bone disorders before and after renal transplantation.

Background/aims: The role of chronic kidney disease-mineral bone disorder (CKD-MBD) reversibility in the amelioration of vascular function and in the reduction of the risk for cardiovascular events after renal transplantation is still unknown.

Methods: We investigated the longitudinal relationship between the main biomarkers of CKD-MBD and the evolution of vascular function [flow-mediated dilatation (FMD)] after transplantation in a series of 161 patients with kidney failure maintained on chronic dialysis (5D-CKD).

Results: Before transplantation, FMD in patients was markedly lower (-40%, p < 0.001) than in well-matched healthy subjects and increased by 27% after transplantation (p = 0.001). Fibroblast growth factor 23 (FGF23), 25-hydroxy-vitamin D (25OHVD) and serum phosphate (p < 0.01) were independently associated with simultaneous changes in FMD. Changes in classical risk factors and in risk factors related to CKD like the glomerular filtration rate, serum albumin, C-reactive protein and insulin resistance failed to independently explain the variability in FMD changes after transplantation.

Conclusion: Endothelium-dependent vasodilatation improves after kidney transplantation, which is parallel to the dramatic fall in FGF23, the reduction in serum phosphorus and the increase in 25OHVD levels. If these associations are causal, a part of decline in cardiovascular risk after transplantation is related to partial resolution of CKD-MBD.