The search for novel biomarkers in sepsis-induced cardiomyopathy – A new challenge to overcome

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection and it remains the most frequent cause of death amongst critically ill patients worldwide, despite recent medical advancements. The cardiac involvement in sepsis, better known as sepsis-induced cardiomyopathy, represents a form of cardiac dysfunction identified in septic patients, characterized by ventricular dilation, myocardial involvement, decreased ejection fraction and reversibility. Although the implications of cardiac involvement in sepsis can be extremely severe, this affliction has not been intensely debated in literature. Therefore, in order to better understand this affliction, we need to identify new markers. Two biomarkers, endothelin-1 (ET-1) and the soluble form of suppression of tumorigenicity 2 protein (sST2) have previously been linked to both sepsis and acute/chronic heart failure. Endothelin-1 is part of a family of amino acid peptides, that is mainly produced by endothelial cells and exerts a vasoconstrictive effect, but also causes fibrosis of the vascular cells, stimulates production of reactive oxygen species and induces proinflammatory mechanisms. During sepsis, it induces coronary vasoconstriction, decreased cardiac output, increased vascular resistance and permeability and increased fluid flux into the extravascular space on cardiac level, as well as affecting the contractility of myocardial myocytes. High values of serum ET-1 have also been identified in septic shock and in endotoxin-induced febrile responses in rats. The Suppression of tumorigenicity 2 protein (ST2) is a member of the interleukin-1 receptor family and is involved in T helper 2 cells-associated immune response. Recent studies identified a close link between ST2 and both inflammatory and heart diseases. Furthermore, it was recently approved by the Food and Drug Administration as a prognostic biomarker in heart failure and is recommended for the evaluation of additional cardiovascular risk.