Editors' ChoiceCardiovascular Disease

A Coat Connects Obesity with Heart Disease

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Science Translational Medicine  05 Jun 2013:
Vol. 5, Issue 188, pp. 188ec95
DOI: 10.1126/scitranslmed.3006622

Obesity is a worldwide public health challenge, and its prevalence and associated comorbidities have increased dramatically in the past three decades. A principal comorbidity associated with obesity is coronary heart disease; however, there is still controversy over the extent of the contribution of obesity to heart disease. Recent evidence suggests that the adipose tissue surrounding the coronary arteries may expand in obese patients. This so-called perivascular adipose tissue (PVAT) may affect the function of the coronary arteries by releasing vasoactive and inflammatory mediators. Now, Owen et al. explore the mechanisms by which PVAT may affect the coronary arteries in lean and obese animals.

Owen and colleagues hypothesized that obesity favors coronary artery vasoconstriction. To test their hypothesis, the authors studied isolated coronary arteries from Ossbaw swine, an animal that develops obesity when exposed to a nutritional excess and physical inactivity. The pigs were fed either standard chow (lean swine) or an atherogenic diet (obese swine) for 6 to 12 months. Arteries were stimulated with potassium chloride solution or prostaglandin F2α before and after incubation with PVAT. Interestingly, PVAT from coronary and mesenteric arteries but not subcutaneous PVAT boosted arterial contraction in response to smooth muscle depolarization with potassium chloride solution. Arterial contractions were dependent on the amount of PVAT added and were greater for coronary arteries from obese versus lean swine. Similar responses to PVAT were observed in coronary arteries from lean and obese swine in which the endothelial lining had been removed. Protein expression profiling of PVAT from lean and obese swine revealed marked differences, including up-regulation of proteins important for smooth muscle contraction (RhoA and calpastatin) in obese but not lean animals.

The results of this study support the notion that PVAT surrounding coronary arteries may independently initiate or augment the contraction of coronary arteries in obese animals. These findings strengthen the direct link between obesity and heart disease and call for future studies to investigate whether this association holds in humans.

M. K. Owen et al. Perivascular adipose tissue potentiates contraction of coronary vascular smooth muscle: Influence of obesity. Circulation, 17 May 2013 (10.1161/CIRCULATIONAHA.112.001238). [Abstract]

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