Purified adipose tissue-derived extracellular vesicles facilitate adipose organoid vascularization through coordinating adipogenesis and angiogenesis

One of the major challenges in the way of better fabricating vascularized adipose organoids is the destructive effect of adipogenic differentiation on preformed vasculature, which probably stems from the discrepancy between the<i>in vivo</i>physiological microenvironment and the<i>in vitro</i>culture conditions. As an intrinsic component of adipose tissue (AT), adipose tissue-derived extracellular vesicles (AT-EVs) have demonstrated both adipogenic and angiogenic ability in recent studies. However, whether AT-EVs could be employed to coordinate the angiogenesis and adipogenesis in the vascularization of adipose organoids remains largely unexplored. Herein, we present an efficient method for isolating higher-purity AT-EV preparations from lipoaspirates, and verify the superiority of AT-EV preparations' angiogenic and adipogenic capabilities over those from unpurified lipoaspirates. Next, in the spheroid culture model, it was discovered that the addition of AT-EVs could effectively improve the aggregation through enhancing intercellular adhesion of monoculture spheroids composed of human umbilical vascular endothelial cells (HUVECs), and helped produce vascularized adipose organoids with proper lipolysis and glucose uptake ability in the coculture spheroids comprised of adipose-derived stem cells (ADSCs) and HUVECs. Subsequently, it was observed that AT-EVs could exert a retaining effect on the vasculature of prevascularized coculture spheroids cultured in an adipogenic environment, compared to the reduced vascular networks where AT-EVs were absent. Altogether, these results indicate that AT-EVs, by means of releasing bioactive molecules that emulate the<i>in vivo</i>microenvironment, can modify non-replicative<i>in vitro</i>microenvironments, coordinate<i>in vitro</i>adipogenesis and angiogenesis, and facilitate the fabrication of vascularized adipose organoids.