Adipokines in periaortic and epicardial adipose tissue: differential expression and relation to atherosclerosis

Adipokines are protein products of adipose tissue with paracrine and endocrine actions, which have been implicated in the pathogenesis of cardiovascular disease. Locally produced adipokines, especially by periadventitial adipose tissue, may affect vascular physiology and pathology. We investigated the expression of adiponectin, visfatin, leptin and novel adipokines chemerin and vaspin in human periaortic and epicardial adipose tissue, as well as their correlation to aortic and coronary atherosclerosis.

Standard immunohistochemical staining for the adipokines was performed on samples of human periaortic, pericoronary and apical epicardial adipose tissue. Atherosclerotic lesions of the adjacent vascular wall were assessed using the AHA classification.

Adipokines were expressed in periadventitial and apical epicardial adipose tissue and - except for adiponectin - in vascular smooth muscle cells and foam cells in atherosclerotic lesions. Aortic atherosclerosis was positively correlated with chemerin, vaspin, visfatin and leptin periaortic fat expression. Coronary atherosclerosis was positively correlated with chemerin and visfatin pericoronary fat expression. Adipose tissue adiponectin expression was negatively correlated to atherosclerosis in both locations. Expression of adipokines in apical epicardial fat was not associated with atherosclerosis.

Our results show: a) a different expression pattern of adiponectin, visfatin, leptin, chemerin and vaspin in periaortic, pericoronary and apical epicardial adipose tissue, b) a correlation of these adipokines with either aortic or coronary atherosclerosis or both in a pattern characteristic for each adipokine and suggest that locally produced adipokines might differently affect the atherosclerotic process in different locations.