Encapsulation of adipogenic factors to promote differentiation of adipose-derived stem cells

Insulin and dexamethasone were encapsulated in poly(lactic-co-glycolic acid) (PLGA) microspheres to induce adipogenesis for potential applications in soft tissue reconstruction. Release kinetics and bioactivity of the drugs were examined. Surface morphology and diameter of the PLGA microspheres was evaluated using scanning electron microscopy. The release of insulin was determined using ELISA whereas the release of dexamethasone was evaluated spectrophotometrically. The activity of the drugs was assessed by releasing the drugs in the presence of human adipose-derived stem cells. The ability of the cells cultured with microspheres to differentiate into adipocytes was evaluated using Oil Red O stains. Cells treated with the dexamethasone and insulin microspheres demonstrated a significant increase in lipid inclusions compared with control groups. Insulin and dexamethasone microspheres can reproduce the adipogenic effect exerted by differentiation medium, and may represent a clinically relevant method of stimulating adipogenesis in tissue engineering therapies.