Coronado MJ, et al. - Researchers studied the association of elevated sera soluble (s)ST2 with acute and chronic heart failure risk in 303 adults with a diagnosis of clinically suspected myocarditis (78% male) and in mice. Healthy men and men with myocarditis exhibited higher sera sST2 levels vs women. Patients with myocarditis and New York Heart Association class III-IV heart failure were found to have elevated sST2 levels, this was predominantly seen in men. Also, remarkably higher levels of sera sST2 were detected in male mice with myocarditis where levels were related to cardiac inflammation. In male mice with myocarditis, increased sera sST2 levels, attributed to testosterone but not to estradiol, were demonstrated by gonadectomy with hormone replacement. Overall, an increased risk of heart failure based on New York Heart Association class in men ≤50 years old was observed in association with elevated sera sST2 in a well-characterized subset of heart failure patients with clinically suspected and biopsy-confirmed myocarditis.