Role of epicardial adipose tissue in coronary artery disease in non-obese patients.
BACKGROUND
Epicardial adipose tissue (EAT) surrounding the heart may contribute to the development of coronary artery disease (CAD) through its local secretion of adipocytokines. Although the quantity of EAT is associated with obesity and metabolic syndrome, the role of EAT in the development of CAD in non-obese patients remains to be determined.


METHODS
This study included 41 patients with CAD who underwent coronary artery bypass graft surgery and 28 patients without CAD who underwent other cardiac surgery. EAT volume was measured by 64-slice multi-detector computed tomography before the surgery. We obtained pericardial fluid and epicardial and subcutaneous adipose tissue samples at the surgery. We investigated the relationship between EAT volume and adiponectin levels in pericardial fluid and incident CAD in patients with and without obesity (body mass index>25 kg/m(2)).


RESULTS
There was no significant difference in EAT volume between obese patients with and without CAD (55.5 ± 40.2 mL vs. 40.1 ± 19.7 mL, p=0.323). However, EAT volume was significantly greater in non-obese patients with CAD compared to those without CAD (35.0 ± 18.8 mL vs. 15.7 ± 11.0 mL, p<0.001). Adiponectin concentrations in pericardial fluid were significantly lower in non-obese patients with CAD compared to those without CAD (2.7 ± 2.0 μg/mL vs. 4.3 ± 3.7 μg/mL, p=0.049), whereas the adiponectin levels were decreased in obese patients regardless of the presence of CAD. Non-obese patients with CAD had significantly larger size adipocytes in EAT but not subcutaneous adipose tissue compared to those without CAD. Multiple logistic regression analysis showed that increased EAT volume was independently associated with incident CAD in non-obese patients.


CONCLUSIONS
Increased EAT may play a crucial role in development of CAD through impairment of adiponectin secretion in non-obese patients.
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Tadateru
T
Iwayama
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Joji
J
Nitobe
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan. Electronic address: tewatana@med.id.yamagata-u.ac.jp.
Tetsu
T
Watanabe
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Mitsunori
M
Ishino
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Harutoshi
H
Tamura
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Satoshi
S
Nishiyama
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Hiroki
H
Takahashi
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Takanori
T
Arimoto
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Tetsuro
T
Shishido
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Takehiko
T
Miyashita
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Takuya
T
Miyamoto
Department of Cardiovascular, Thoracic and Pediatric Surgery, Yamagata University School of Medicine, Yamagata, Japan.
Shuji
S
Toyama
Department of Cardiovascular, Thoracic and Pediatric Surgery, Yamagata University School of Medicine, Yamagata, Japan.
Mitsuaki
M
Sadahiro
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Isao
I
Kubota
D052242:Adiponectin / Q000378:metabolism*; D000273:Adipose Tissue / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D000368:Aged; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000209:etiology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009765:Obesity / Q000378:metabolism / Q000473:pathology; D010496:Pericardium / Q000378:metabolism* / Q000473:pathology*
D052242:Adiponectin
Computed tomography; Coronary artery disease; Cytokines; Risk factors