Endothelial cells from visceral adipose tissue disrupt adipocyte functions in a three-dimensional setting: Partial rescue by angiopoietin-1

Abstract

During obesity, chronic inflammation of human white adipose tissue (WAT) is associated with metabolic and vascular alterations. Endothelial cells from visceral WAT (VAT-ECs) exhibit a proinflammatory and senescent phenotype and could alter adipocyte functions. We aimed to determine the contribution of VAT-ECs to adipocyte dysfunction related to inflammation and to rescue these alterations by antiinflammatory strategies. We developed an original three-dimensional setting allowing maintenance of unilocular adipocyte functions. Coculture experiments demonstrated that VAT-ECs provoked a decrease in the lipolytic activity, adipokine secretion, and insulin sensitivity of adipocytes from obese subjects, as well as an increased production of several inflammatory molecules. Interleukin (IL)-6 and IL-1b were identified as potential actors in these adipocyte alterations. The inflammatory burst was not observed in cocultured cells from lean subjects. Interestingly, pericytes, in functional interactions with ECs, exhibited a proinflammatory phenotype with diminished angiopoietin-1 (Ang-1) secretion in WAT from obese subjects. Using the anti-inflammatory Ang-1, we corrected some deleterious effects of WAT-ECs on adipocytes, improving lipolytic activity and insulin sensitivity and reducing the secretion of proinflammatory molecules. In conclusion, we identified a negative impact of VAT-ECs on adipocyte functions during human obesity. Therapeutic options targeting EC inflammation could prevent adipocyte alterations that contribute to obesity comorbidities. © 2014 by the American Diabetes Association.