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.

The relation between pericoronary fat thickness and density quantified by coronary computed tomography angiography with coronary artery disease severity

“…Epicardial adipose thickness (EAT) which is a component of visceral adipose tissue and correlates strongly with visceral abdominal fat, increases with obesity. 14 …”

Exploring the role of epicardial adipose-tissue-derived extracellular vesicles in cardiovascular diseases

“…The adipose tissue of the heart can be categorized into two distinct compartments according to their respective anatomical location: epicardial fat and pericardial fat. 13 EAT is the fat depot located between the myocardium and the visceral layer of the epicardium, whereas the pericardial fat is located on the outer surface of the parietal pericardium. 14 EAT accumulates within the interventricular and atrioventricular grooves and is present along the coronary vessels, the right edge of the wall of the right ventricle, on the anterior wall, and around the apex of the heart.…”

“…In this way, it may exert a protective role by releasing anti-inflammatory adipokines with cardioprotective effects (i.e., adiponectin). 13 …”

“…Indeed, it represents an indispensable energy source for the myocardium, providing energy through the beta-oxidation of long chain fatty acids, which are then used by the heart as its main energy source. 13 EAT exhibits a greater ability to take up and release FFAs compared with other fat depots and, given the proximity between EAT and cardiomyocytes, FFAs may directly diffuse from EAT into the myocardial cells, or they can be actively transported through the coronary circulation. 17 , 22 Adipocyte fatty-acid-binding protein (also known as FABP4), highly expressed in EAT, participates in the intracellular transport of fatty acids from epicardial fat into the myocardium, while however protecting the myocardium from exposure to high fatty acid levels.…”

Myocardial fat accumulation is associated with cardiac dysfunction in patients with type 2 diabetes, especially in elderly or female patients: a retrospective observational study

“…In the heart, epicardial fat is another type of ectopic fat. Epicardial fat is increased in patients with type 2 diabetes [6], and its accumulation is associated with the presence of coronary artery disease and cardiac arrhythmias [7][8][9]. Moreover, the accumulation of triglycerides (TGs) in coronary arteries has been recently reported [10,11].…”