Abstract
CONTEXT: Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice. The increasing evidence supports links between inflammation and AF. There is evidence showing that obesity is a major cause of adipose tissue (AT) inflammation. Ghrelin (GHRL), through its growth hormone secretagogue receptor (GHS-R) present on adipose tissue macrophages (ATMs), could modulate AT inflammation. OBJECTIVE: Our study aimed to evaluate the role of adipose tissue macrophages (ATMs) and their GHS-R in adipose tissue samples of right atrial appendages (RAA) biopsies. SUBJECTS AND METHOD: We obtained RAA biopsies from 10 obese patients, undergoing cardiac surgery for coronary artery bypass graft (CABG) and developing postoperative atrial fibrillation (POAF). The epicardial tissue samples were examined using immunohistochemistry to visualize and quantify CD68 and GSH-R expression of the ATMs. RESULTS: Histologically, the mean adipocyte diameter (MAD) of epicardial adipose tissue (EAT) was larger in EAT samples with inflammation as compared to EAT without inflammation (84.2 µm vs. 79.6 µm). The expression of CD68 was lower in EAT without inflammation as compared to EAT with inflammation in adipose tissue samples. Similarly, the expression of GSH-R was lower in EAT samples without inflammation as compared to EAT samples with inflammation in adipose tissue. CONCLUSIONS: Increased epicardial fat area, macrophage infiltration, and GHS-R expression in epicardial ATMs appeared to be associated with postoperative atrial fibrillation in obese patients.