Vascular calcification in uremic conditions : new insights into pathogenesis

Chronic kidney disease (CKD) patients have an higher incidence of cardiovascular morbidity and mortality compared with the general population. In the past 10 years, several studies pointed out that vascular calcification is a major cause of cardiovascular disease in the dialysis population. In CKD patients, high levels of serum phosphate and parathyroid hormone play a critical role in the pathogenesis of cardiovascular events. Calcium- and aluminum-free phosphate binders provide a new and effective therapeutic tool in preventing cardiovascular calcifications in CKD in animal models and in hemodialysis patients. Moreover, the pathogenesis of vascular and soft-tissue calcification, which traditionally has been associated with a passive calcium-phosphate deposition, certainly also is related to an active, cell-mediated process. In fact, some bone regulatory proteins seem to be able to induce or inhibit mineral deposition in the vasculature. In particular, bone matrix protein 7, α2-HS glycoprotein, and matrix GLA protein may be regulatory keys in preventing extraskeletal calcification in uremic conditions. This review presents the current understanding of the pathogenesis of vascular calcification in CKD patients, focusing on these 3 proteins and their protective action on extraskeletal calcification.