Epicardial adipose tissue, metabolic disorders, and cardiovascular diseases: recent advances classified by research methodologies

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  FIGURE 1. Three categories of research in the area of epicardial adipose tissue (EAT). Studies in the area of EAT can be classified into three categories according to their research methodology, namely studies based on imaging techniques, in‐depth profiling of EAT, and in vitro cocultural studies. Simultaneously, these three categories of investigations also represent the continuous deepening process of our understanding of EAT. First, studies based on imaging techniques made important contributions to demonstrate the association between EAT and cardiovascular diseases (CVDs). Second, in‐depth profiling of EAT and its secretome allowed us to gain deeper insights into the key role played by EAT in CVDs. Third, coculture studies were conducted to explore the paracrine effects of EAT on cardiomyocytes.

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  FIGURE 2. Milestones in the development of imaging techniques used in EAT‐related research. In 2001, Taguchi et al. first proposed a CT‐based measurement of EAT volume. In 2003, Iacobellis et al. first proposed using echocardiography to measure EAT thickness. Around 2015, algorithms for fully automated EAT segmentation and quantification emerged. In 2017, Antonopoulos et al. first proposed fat attenuation index of EAT as a novel imaging biomarker. In 2019, Oikonomou et al. first applied radiomics for analyzing EAT.

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  FIGURE 3. Interventions targeting epicardial adipose tissue (EAT). Four types of interventions have been proposed to reduce EAT volume, including exercise interventions, dietary interventions, bariatric surgery, and pharmaceutical interventions. Several types of exercise training protocols and dietary interventions have proven effective in reducing EAT amount. Besides, bariatric surgeries, including sleeve gastrectomy and Roux‐en‐Y gastric bypass, can lead to pronounced effects in decreasing EAT, as well as other fat deposits. Finally, drugs including sodium‐glucose cotransporter‐2 (SGLT‑2) inhibitors, glucagon‐like peptide‐1 (GLP‐1) analogues and statins have been studied to reduce EAT amount.

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  FIGURE 4. Association between epicardial adipose tissue (EAT) and metabolic disorders. EAT amount measured by imaging techniques is significantly higher in patients with metabolic disorders. An increased EAT volume is associated with a higher risk of developing metabolic syndrome, cardiovascular mortality, atrial fibrillation (AF) incidence, and reduced cardiac function. Further, in‐depth profiling studies suggest that EAT is remodeled into a more proinflammatory phenotype in patients with metabolic disorders. Finally, coculture studies explored the paracrine effect of EAT and provided preliminary evidence that EAT might be a link between metabolic disorders and CVDs.