Plasma and Cardiac Galectin-3 in Patients With Heart Failure Reflects Both Inflammation and Fibrosis: Implications for Its Use as a Biomarker.

BACKGROUND Galectin (Gal)-3 is a β-galactoside-binding lectin and currently intensely studied as a biomarker in heart failure. Gal-3 also exerts proinflammatory effects, at least in extracardiac tissues. Objective of this study was to characterize the relationship of plasma and myocardial Gal-3 levels with cardiac fibrosis and inflammation in patients with nonischemic dilated cardiomyopathy and inflammatory cardiomyopathy (iCMP). METHODS AND RESULTS Endomyocardial biopsies and blood samples were obtained from patients with newly diagnosed cardiomyopathy and clinical suspicion of myocarditis. According to histopathologic findings, patients were classified as having dilated cardiomyopathy (n=40) or iCMP (n=75). Cardiac fibrosis was assessed histologically on endomyocardial biopsy sections. In patients with iCMP, myocardial Gal-3 expression significantly correlated with inflammatory cell count on endomyocardial biopsy (r=0.56; P<0.05). In contrast, an inverse association was observed between myocardial Gal-3 expression and cardiac fibrosis in patients with iCMP (r=-0.59; P<0.05). In patients with dilated cardiomyopathy, myocardial Gal-3 expression correlated with cardiac fibrosis on left ventricular biopsy (P=0.63; P<0.01). Of note, in both groups, plasma Gal-3 levels did not correlate with myocardial Gal-3 levels or left ventricular fibrosis, whereas a positive correlation between plasma Gal-3 levels and inflammatory cell count on endomyocardial biopsy was observed in patients with iCMP. CONCLUSIONS The present study suggests that myocardial Gal-3 can be considered as a possible marker for both cardiac inflammation and fibrosis, depending on the pathogenesis of heart failure. However, circulating concentrations of Gal-3 do not seem to reflect endomyocardial Gal-3 levels or cardiac fibrosis.