Role of Vitamin D in Uremic Vascular Calcification

Table 1

Potential roles of vitamin D in preventing vascular calcification on endothelium and vascular smooth muscle.

Alleviating endothelial calcification	Mechanism	Alleviating arterial calcification	Mechanism
Inhibition of foam cell and cholesterol efflux in macrophage	(1) Activation of cholesterol 7-α-hydroxylase; (2) Decrease of oxidative LDL uptake by foamy cells; (3) Decrease of ER stress by differentiation of macrophage	Treatment on renal osteodystrophy	(1) On high-turnover osteodystrophy: inhibition of parathyroid hormone; (2) On low-turnover osteodystrophy: restoring osteoblast activity
Enhancing vascular regeneration	(1) Providing circulating CD45−CD117+Sca1+Flk1+ angiogenic myeloid cells; (2) Downregulating thrombotic cytokine from vascular smooth muscle cells	Restoring calcification inhibitors	(1) Increase of fetuin-A concentration; (2) Restoring local klotho expression; (3) Restoring osteopontin expression
RAAS system inactivation	(1) Downregulating renin expression; (2) Decrease of urine angiotensinogen and intrarenal RAAS activation	Regressing residual proteinuria	(1) RAAS inactivation; (2) Lessening TGF-β1 induced tubulointerstitial fibrosis
Improving insulin resistance	(1) Decrease of pancreatic beta cell destruction; (2) Increase of beta cell insulin secretion; (3) Increase of insulin sensitivity