The differentiation of beige adipocyte in pericardial and epicardial adipose tissues induces atrial fibrillation development.

OBJECTIVE: Growing evidence has identified that excessive accumulation of pericardial adipose tissues (PAT) and epicardial adipose tissues (EAT) is associated with atrial fibrillation (AF) development. Moreover, beige adipocytes, present in PAT and EAT, have been proved beneficial in consumption of fatty acid and promotion of weight lose by nonshivering thermogenesis. The objective of this prospective, observational study was to reveal the potential association between beige adipocytes and AF development.

PATIENTS AND METHODS: Fat tissues from subcutaneous adipose tissue (SAT), PAT and EAT were obtained from 70 AF and 30 sinus rhythm patients. Hematoxylin and eosin (H&E) staining were performed to analyze morphological changes in fat tissues. Real-time PCR was performed to identify mRNA expression of unique uncoupling protein-1 (UCP-1). Western blotting and immunohistochemistry (IHC) were performed to determine protein expression of UCP-1.

RESULTS: Our results indicated that pericardial and epicardial adipocytes in AF patients demonstrated white-like change tendency and had lower expression of UCP-1 when compared to sinus rhythm patients. Additionally, the decrease of UCP-1 mRNA expression in PAT and EAT, together with LA enlargement, were independent risk factors of AF. Further, UCP-1 mRNA expression in EAT, but not in PAT, have a significant correlation with LA diameter. The function of nonshivering thermogenesis in PAT and EAT was impaired in AF patients, and this dysfunction in EAT had a great correlation with LA dilation.

CONCLUSIONS: Our data provide a new therapeutic target for LA remodeling and AF treatment.