Follistatin-Like 1 in Chronic Systolic Heart FailureClinical Perspective: A Marker of Left Ventricular Remodeling

Background— Follistatin-like 1 (FSTL1) is an extracellular glycoprotein found in human serum. Recent work suggests that FSTL1 is secreted in response to ischemic injuries and that its overexpression is protective in the heart and vasculature. Methods and Results— We examined serum FSTL1 levels in patients with chronic heart failure with left ventricular (LV) ejection fraction P P =0.09). After adjusting for significant parameters, patients with increased FSTL1 remained at the highest risk of death (hazard ratio, 1.028; 95% CI, 0.98 to 1.78; P =0.26). To determine whether elevated FSTL1 levels may be derived from the myocardium, FSTL1 protein expression was measured in explanted failing (n=18) and nonfailing (n=7) human hearts. LV failing hearts showed 2.5-fold higher FSTL1 protein levels over nonfailing control hearts ( P Conclusions— Elevated serum FSTL1 in patients with heart failure was associated with LV hypertrophy. Further studies on the role of FSTL1 as a biomarker in chronic systolic heart failure are warranted.