Fetuin-A (AHSG) and its usefulness in clinical practice. Review of the literature

Background. Fetuin-A, also called Alpha 2-Heremans Schmid Glycoprotein, is a multifunctional plasma agent what has been proven in animal and human studies. It plays a role as a physiological inhibitor of insulin receptor tyrosine kinase associated with insulin resistance and a negative acute phase reactant. It also regulates bone remodeling and calcium metabolism being an important inhibitor of calcium salt precipitation and vascular calcifications. Methods. PubMed database was searched for articles from 2002 up to December 2014 to identify the role of fetuin-A in the pathogenesis of selected internal diseases. Results. Due to secretion of fetuin-A mainly by the liver, it may be a marker of liver function and predictor of mortality in patients with cirrhosis and hepatocellular cancer. The associations between high fetuin-A and metabolic syndrome as well as its hepatic manifestation-nonalcoholic fatty liver disease and atherogenic lipid profile have been well proven. However, fetuin-A relation with BMI is not so clear. Contrary to few reports, many authors suggest that fetuin-A may be an independent risk factor for type 2 diabetes and marker of diabetic complications. Close associations of high and low fetuin-A concentrations with cardiovascular diseases and mortality risk have been reported which is explained by differences in analyzed populations, stages of atherosclerosis and calcifications, coexistence of type 2 diabetes or kidney dysfunction and different main pathways of fetuin-A actions in various diseases. Conclusions. Fetuin-A has a diagnostic potential as a biomarker for liver dysfunction, cardiovascular diseases and disorders associated with metabolic syndrome.