Thiazolidinediones and glucocorticoids synergistically induce differentiation of human adipose tissue stromal cells: Biochemical, cellular, and molecular analysis

While adipocyte differentiation has been studied extensively in murine cult ures, the lack of a readily available preadipocyte model has hindered equiv alent studies in man. We describe methods for the isolation and culture of primary human stromal cells from surgical adipose tissue specimens. In vitr o, the stromal cells rapidly differentiate in response to a combination of adipogenic agents; Among these, glucocorticoids and thiazolidinediones act together to induce the formation of lipid vacuoles within the cells. These morphologic changes accompany the increased expression of 2 characteristic adipocyte proteins, the cytoplasmic enzyme glycerol phosphate dehydrogenase (GPDH) and the secreted cytokine leptin. Likewise, stromal cell differenti ation results in elevated mRNA levels for the fatty acid binding protein aP 2 and the adipogenic regulatory transcription factors CCAAT/enhancer bindin g protein alpha (C/EBP alpha) and peroxisome proliferator-activated recepto r gamma (PPAR gamma) in addition to leptin. The in vitro differentiated str omal cells exhibit a lipolytic response to beta -adrenergic agonists, compa rable to that reported with primary human adipocytes. These studies demonst rate the validity of human adipose tissue-derived stromal cells as a reliab le in vitro model for investigations of adipocyte metabolism in humans. Cop yright (C) 2001 by W.B. Saunders Company.