Serum heat shock proteins as novel biomarker for heart failure and cardiovascular diseases

Abstract

Heat shock proteins (HSPs) or chaperonins, as they were previously named, are a group of evolutionarily conserved proteins that show high sequence homology between different species, from bacteria to humans (Morimoto. Science. 1993;259:1409-10). They are involved in maintaining various cellular proteins in their correctly folded functional forms (Patterson and Cyr. Circulation. 2002;106:2741-6). These proteins have several functions such as cytoprotection and intracellular assembly, stabilization, folding, and translocation of oligomeric proteins (Hightower. Cell 1991;66:191-7). In particular, heat shock protein 60 (HSP60) is a mitochondrial protein constitutively expressed in the majority of cells, and its expression is upregulated by a variety of stressors. In the setting of cardiovascular disease, higher titers of antibody to HSPs have been reported in atherosclerosis, which may contribute to immunoactivation in this process and other similar conditions. In heart failure, HSP60 is released from cardiomyocytes; it has been demonstrated in several studies that increased serum HSP60 is related to the severity of the disease. In fact, high levels of sHSP60 correlate with worse prognosis and higher mortality rate in patients with acute heart failure (AHF) (Bonanad et al. Congest Heart Fail. 2013;19:6-10).