The Role and Implications of Epicardial Fat in Coronary Atherosclerotic Disease

Abstract

The current minireview aims to assess the implications of epicardial fat secretory function in the development of coronary artery disease. The epicardial adipose tissue (EAT) is a visceral fat depot that has been described as a cardiovascular risk factor. In addition to its mechanical protection role and physiological secretory function, it seems that various secretion products of the epicardial fat are responsible for metabolic disturbances at the level of the cardiac muscle when in association with pre-existing pathological conditions, such as metabolic syndrome. There is a pathological reduction in sarcomere shortening, abnormal cytosolic Ca²⁺ fluxes, reduced expression of sarcoplasmic endoplasmic reticulum ATPase 2a and decreased insulin-mediated Akt-Ser473-phosphorylation in association with abnormal levels of epicardial fat tissue. Activin A, angiopoietin-2, and CD14-positive monocytes selectively accumulate in the diseased myocardium, resulting in reduced cardiomyocyte contractile function. At the same time, it is believed that these alterations in secretory products directly decrease the myocyte function via molecular changes, thus contributing to the development of coronary disease when certain comorbidities are associated.

Keywords: atherosclerosis; coronary artery disease; epicardial fat; metabolic syndrome; oxidative stress.

Figure 1

Intra-operative view of EAT. Left ventricle (LV); Right ventricle (RV); Left anterior descending artery (LAD); Internal mammary artery (IMA); Epicardial adipose tissue (EAT); Myocardium (M); Pericardium (P). Photo collected from own practice and obtained with patient’s consent.

Figure 2

Anatomical description. Epicardial fat (A). Pericardial fat (B). Pericardium (C). The myocardium (D). Aorta (E). Photo collected from own practice and obtained with patient’s consent.

Figure 3

Epicardial fat by transthoracic echocardiography. (a). Epicardial fat thickness at parasternal long axis (the distance from outer side of myocardium to pericardium). (b). Epicardial fat by transthoracic echocardiography. Epicardial fat thickness at parasternal short axis (the distance from outer side of myocardium to pericardium). EAT—Epicardial Adipose Tissue; RV—Right Ventricle; LV—Left Ventricle; Ao—Aorta; LA—Left Atrium. White arrows pointing towards the EAT; Yellow arrow pointing towards the magnified view of EAT.