BACKGROUND: Our study focused on the ability of epicardial adipocytes to produce bioactive substances and compare the extent of this production with the production of adipokines in visceral adipocytes, which are well known endocrine cells capable of contributing to the development of atherosclerosis.
MATERIAL AND METHODS: The gene expression of human cytokines (IL-6, IL-8, IL-18, RANTES and MCP-1) and adipokines (leptin and adiponectin) was measured in primary cell lines of epicardial and visceral adipocytes, both in undifferentiated and mature statuses, after a 21-day-long differentiation protocol. Each condition was assayed in triplicate in two independent primary cell lines obtained from two different donors.
RESULTS: The epicardial preadipocytes showed an increased expression of IL-8 (3.25-fold, p<0.05) compared with visceral preadipocytes. The expression of the atheroprotective adiponectin in epicardial preadipocytes was minimal compared with the expression in visceral preadipocytes (p<0.0001). Moreover, the expression of the genes of interest was dependent on the differentiation degree and cell origin. We observed an altered expression of the proinflammatory genes IL-8 (0.016-fold, p<0.01) and MCP-1 (0.19-fold, p<0.05) in differentiated epicardial adipocytes compared with undifferentiated adipocytes. The epicardial adipocytes showed an increased expression of IL-6 (8.13-fold, p<0.05) compared with the visceral adipocytes.
CONCLUSION: Our results suggest that epicardial adipocytes substantially differ from visceral adipocytes and might locally contribute to the pathogenesis of coronary atherosclerosis.