ST2 as a cardiovascular risk biomarker: from the bench to the bedside.

ST2 is a member of the interleukin (IL)-1 receptor family discovered in a classical translational science fashion, and exists in two forms, a trans-membrane receptor (ST2L) as well as a soluble decoy receptor (sST2). The ligand of ST2 is IL-33, which is involved in reducing fibrosis and hypertrophy in mechanically strained tissues. In in vitro and in vivo models, ST2L transduces the effects of IL-33, while excess sST2 or abnormalities in ST2 signaling leads to cardiac hypertrophy, fibrosis, and ventricular dysfunction. Clinically, in patients with symptomatic heart failure (HF), elevated concentrations of sST2 are strongly associated with severity of the diagnosis, and powerfully predict increased risk of complications, independent of other established or emerging biomarkers. sST2 testing has also been shown to predict onset of symptomatic HF in patients with acute myocardial infarction, while in community-based subjects, sST2 values independently predict future HF, cardiovascular disease events, and mortality.