Heart fat infiltration in subjects with and without coronary artery disease

Context: Fat may accumulate around the heart in epicardial adipose tissue or inside the heart as lipid droplets (LDs). Objective: To compare myocardial steatosis between subjects with and without coronary artery disease (CAD and non-CAD) and to identify which cells contain LDs. Design: Body mass index, waist circumference, glucose, insulin, HOMA index, leptin, adiponectin and hs-CRP were evaluated in CAD and non-CAD subjects. Biopsies were collected from right atrial myocardium. Immunohistochemistry for perilipin (PLIN) 1 and 2 was used to characterize LDs and their localization respectively in adipocytes or myocardial cells. Cardiomyocytes apoptosis and HIF1 alpha were obtained in a subgroup of subjects . Setting: Hospitalized patients Patients: Male subjects consecutively undergoing elective cardiac surgery either for coronary bypass grafting (CAD, n 23) or for valve replacement (non-CAD, n18). Main outcome: Myocardial steatosis. Results: PLIN1 and PLIN2 resulted significantly higher in CAD than in non-CAD subjects, as well as apoptosis; PLIN 1 was positively associated with circulating leptin, hs-CRP and apoptosis, and negatively with adiponectin. PLIN 2 was positively associated with BMI, waist circumference, leptin and negatively with adiponectin. After taking into account absence/presence of hypertension, diabetes and CAD/non-CAD, adiponectin resulted negatively associated with PLIN1 (R2 0.532); waist circumference and adiponectin were associated with PLIN2 (R2 0.399). Conclusions: Myocardial steatosis is greater in CAD than non-CAD subjects, depending on both metabolically active adipocytes interspersed among cardiomyocytes, and higher fat deposition inside cardiomyocytes; serum adiponectin and waist are independent predictors of myocardial steatosis.