Beneficial paracrine effects of adipocytes from obese rats on cultured endothelial cells

The purpose was to test the hypothesis that adipocytes from obese rats would exert pro-atherogenic paracrine effects on cultured endothelial cells compared to adipocytes from lean rats, and that the adverse obesity-associated paracrine effects of adipocytes would be more pronounced in visceral than subcutaneous adipose tissue. Epididymal and subcutaneous adipose tissues were harvested from 32-wk old obese Otsuka Long Evans Tokushima Fatty (OLETF) and lean Long Evans Tokushima Otsuka (LETO) rats. Cultured rat aortic endothelial cells were treated for 24 hours with media conditioned with LETO subcutaneous adipocytes (LSA), OLETF subcutaneous adipocytes (OSA), LETO epididymal adipocytes (LEA), and OLETF epididymal adipocytes (OEA). The amounts of key adipokines secreted by ATs was measured in the supernatant fluid with ELISA and mRNA levels of a number of pro- and anti-atherogenic genes was assessed in treated endothelial cells via quantitative real-time PCR. Compared to adipocytes from other depots, secretion of leptin and TNFα was highest and vaspin secretion was lowest from OEA. However, endothelial cells treated with OEA conditioned media exhibited lower expression of several pro-atherogenic genes. These data suggest that adipocytes isolated from obese visceral adipose tissue secrete some as-yet unidentified factor(s) that confers a beneficial effect on transcription of pro- and anti-atherogenic genes of endothelial cells.