Fetuin-A , also known as Alpha-2-HS-Glycoprotein (AHSG) , belongs to the Fetuin family , is a plasma binding protein , and is more abundant in fetal than adult blood. It is involved in several functions , such as endocytosis , brain development and the formation of bone tissue. Fetuins are carrier proteins like albumin. Fetuin-A forms soluble complexes with calcium and phosphate and thus is a carrier of otherwise insoluble calcium phosphate. Thus Fetuin-A is a potent inhibitor of pathological calcification. The circulating levels of fetuin-A , a well-described inhibitor of calcification , regulate the cell-dependent process of osteogenesis. The low circulating fetuin-A levels are associated with a greater prevalence and/or severity of Vascular calcification (VC) and increased risk for all-cause and cardiovascular mortality. However , high circulating fetuin-A levels appear to induce insulin resistance and , in non-dialyzed subjects with diabetic nephropathy , are directly related to VC burden. The emerging role of fetuin-A deficiency as a risk factor in dialysis patients was documented in cross-sectional studies demonstrating a significant correlation with all-cause and cardiovascular mortality. Additionally , Human fetuin-A is a negative acute phase protein involved in inflammatory diseases , thus being a potential physiological regulator of meprin activity. Fetuin-A is a broad-range protease inhibitor. Fetuin-A and cystatin C as endogenous proteolytic regulators of meprin activity broadens our understanding of the proteolytic network in plasma.
