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Epicardial adipose tissue (or epicardial fat) is the adipose tissue depot mainlysurrounding the epicardial coronary vessels (Figs. 8.3, 8.4, 8.5, and 8.6). It is a
metabolically active part of the heart and it secretes numerous bioactive molecules,
such as inflammatory adipokines, growth factors, and cardioprotective factors. A
recent meta-analysis demonstrated that epicardial adipose tissue is significantly
thicker in patients with coronary artery disease compared to healthy patients [ 61 ].
Numerous studies propose that interactions occur between the epicardial adipose
tissue and the remodeling myocardium, which underpin the etiology of coronary
artery disease, various metabolic syndromes, and atrial fibrillation [ 62 – 64 ]. A num-
ber of studies have shown that epicardial adipose tissue causes an overproduction of
several pro- and anti-inflammatory cytokines and bioactive substances, including
leptin, tumor necrosis factor-alpha, and adiponectin [ 65 , 66 ]. The protein hormone
adiponectin can be produced by other cell types, including cardiomyocytes. Under
physiological conditions, its expression level in cardiomyocytes is significantly
lower than in adipose tissue. The main source of plasma adiponectin is the adipose
tissue [ 67 ]. Adiponectin is a protective factor for the heart. It is characterized by its
anti-inflammatory, anti-atherogenic, anti-apoptotic, and anti-hypertrophic effects.
Many studies show that adiponectin levels decrease in patients suffering from dia-
betes mellitus, coronary artery disease, hypertension, or dilated cardiomyopathy
[ 68 – 70 ]. On the other hand, Takahashi et al. [ 71 ] showed that adiponectin is
expressed by injured cardiomyocytes in patients with myocardial infarction or
dilated cardiomyopathy. Furthermore, Takano et al. [ 72 ] suggested that the heart
Fig. 8.3 The epicardium of the human heart containing epicardial adipose tissue (EAT) visualized
by light microscopy. Mes mesothelium, CV coronary vein, Myo myocardium (H&E stain, Orig.
Magn. 50×)
I. Varga et al.