TABLE 2.
Studies exploring the phenotype of EAT.
| Study | Year published | Experimental vs. control groups | Sample collection | Detecting method | Involved adipocytokines or cytokines | Major findings |
|---|---|---|---|---|---|---|
| Mazurek et al. 41 | 2003 | EAT vs. SAT (n = 42, paired samples) | EAT and SAT samples, collected form patients undergoing CABG surgery | RT‐PCR, ELISA | IL‐1β, IL‐6, MCP‐1, and TNF‐α | The levels of IL‐1β, IL‐6, MCP‐1, and TNF‐α in EAT were significantly higher than SAT. |
| Iacobellis et al. 205 | 2005 | CAD (n = 16) vs. non‐CAD (n = 6) | EAT samples collected form CAD‐patients (undergoing CABG surgery) and non‐CAD patients (undergoing valve replacement or atrium septal defect repair) | Western blot | Adiponectin | The level of adiponectin EAT was significantly lower in CAD‐patients than non‐CAD patients. |
| Baker et al. 206 | 2006 | EAT (n = 46) vs. omental fat (n = 14) vs. abdominal SAT (n = 30) vs. gluteal SAT (n = 13) | EAT, omental fat, abdominal SAT, and gluteal SAT samples, collected from patients undergoing CABG surgery | RT‐PCR | Resistin, adiponectin |
The level of resistin in EAT was threefold higher than that in gluteal adipose tissue. The level of adiponectin EAT is significantly lower than that in omental fat, abdominal SAT, and gluteal SAT. |
| Kremen et al. 207 | 2006 | Preoperative vs. postoperative (n = 15, paired samples) | EAT and SAT samples, collected at the beginning (considered as preoperative) and before the end (considered as postoperative) of elective cardiac surgery (10 CABG surgeries and 5 valvular plastique) | RT‐PCR | Leptin, adiponectin, CD14, CD68, Resistin, MCP‐1, IL‐6 |
The levels of IL‐6, resistin, and MCP‐1 in both EAT and SAT significantly increased at the end of the surgery. The levels of Leptin, adiponectin, CD14, and CD68 did not change significantly. |
| Cheng et al. 208 | 2008 | CAD (n = 46) vs. non‐CAD (n = 12) | EAT and abdominal adipose tissue samples, collected from CAD‐patients (undergoing CABG surgery) and non‐CAD patients (undergoing valve replacement or atrium septal defect repair) | ELISA | TNF‐a, IL‐6, leptin, visfatin, adiponectin |
The levels of TNF‐a, IL‐6, leptin, and visfatin in conditioned media of EAT form CAD patients were significantly higher than non‐CAD patients. The level of adiponectin in conditioned media of EAT form CAD patients was significantly lower than non‐CAD patients. |
| Eiras et al. 209 | 2008 | CAD (n = 58) vs. non‐CAD (n = 34) | EAT and SAT samples, collected form CAD‐patients (undergoing CABG surgery) and non‐CAD patients (undergoing valve surgery) | RT‐PCR | Adiponectin, IL‐6 |
EAT of CAD patients expressed higher level of IL‐6 and lower level of adiponectin compared with non‐CAD patients. Increased extension of CAD is significantly associated with higher level of IL‐6 and lower level of adiponectin in EAT. |
| Eiras et al. 210 | 2010 | EAT vs. SAT (n = 55, paired samples) | EAT and SAT samples, collected from patients undergoing elective cardiac surgery (CABG or valve replacement) | Nitroblue tetrazolium chloride assays (for measuring ROS) | Production of reactive oxygen species (ROS) | The level of oxidative stress is greater in EAT than SAT in patients with CVDs. |
| McAninch et al. 111 | 2015 | EAT vs. SAT (n = 23, paired samples) | EAT and SAT samples, collected form CAD‐patients (undergoing CABG surgery) and non‐CAD patients (undergoing valve surgery) | Transcriptome |
The EAT transcriptome is distinct form SAT. Relative to SAT, EAT is a highly inflammatory tissue. |
|
| Du et al. 211 | 2016 | CAD (n = 28) vs. non‐CAD (n = 12) | EAT and SAT samples, collected form CAD‐patients (undergoing CABG surgery) and non‐CAD patients (undergoing valve surgery) | RT‐PCR | Omentin‐1, adiponectin |
The levels of omentin‐1 and adiponectin in EAT of CAD patients were significantly lower than non‐CAD patients. In CAD patients, omentin‐1 expression was lower in EAT surrounding coronary segments with stenosis than those without stenosis. |
| Gruzdeva et al. 212 | 2017 | EAT vs. SAT (n = 24 paired samples) | EAT and SAT samples, collected form patients undergoing CABG surgery | ELISA | Leptin, TNF‐α, IL‐1, adiponectin, IL‐10, FGF‐β |
The levels of leptin, soluble leptin receptor, TNF‐α, and IL‐1 were higher in cultured adipocytes form EAT than SAT. The levels of anti‐inflammatory cytokines, including adiponectin, IL‐10 and FGF‐β were lower in cultured adipocytes form EAT than SAT. |
| Gruzdeva et al. 213 | 2019 |
EAT vs. SAT (n = 84, paired samples) Subgroup: Obesity (n = 54) vs. nonobesity (n = 30) |
EAT and SAT samples, collected form patients undergoing CABG surgery | RT‐PCR | Adiponectin, IL‐10, leptin, IL6, TNF‐α |
The levels of adiponectin and IL‐10 were lower in cultured adipocytes form EAT than SAT. The levels of leptin, IL6, and TNF‐α were higher in cultured adipocytes form EAT than SAT. The level of adiponectin was lower in cultured EAT and SAT adipocytes form obese patients than nonobese patients. |
| Sardu et al. 214 | 2019 | Prediabetic patients (n = 180) vs. normoglycemic (NG) patients (n = 180) (matched patients) | EAT and SAT samples, collected form patients undergoing CABG surgery | ELISA | Proinflammatory tone, defined as TNF‐α, reduced SIRT6 levels, and leptin to adiponectin ratio | The level of inflammatory tone was higher in prediabetic patients than NG‐patients and was highly associated with the MACE during the 12‐months follow‐up. |
| Zhang et al. 215 | 2019 | CAD (n = 38) vs. non‐CAD (n = 40) | EAT and SAT samples, collected form CAD‐patients (undergoing CABG surgery) and non‐CAD patients (undergoing valve surgery or atrium septal defect repair) | RT‐PCR, immunohistochemistry | Leptin |
The level of leptin in EAT of CAD‐patients was significantly higher than non‐CAD patients. In subgroup analysis, the level of leptin in EAT of CAD‐patients with local coronary stenosis near the right coronary artery ostium was significantly higher than those without. |
Abbreviations: CABG, coronary artery bypass grafting; CAD, coronary artery disease.; EAT, epicardial adipose tissue; MCP‐1, monocyte chemoattractant protein‐1; RT‐PCR: real‐time polymerase chain reaction, ELISA: enzyme‐linked immunosorbent assay; SAT, subcutaneous adipose tissue; TNF‐α, tumor necrosis factor‐α.