STEM CELLS AND DEVELOPMENT 15:719–728 (2006)

Regulation of adipocyte differentiation is an important process in the control of adipose tissue de-velopment. So far, adipogenesis has been investigated through the use of various experimental mod-els. In this work, we used human mesenchymal stem cells (hMSCs) obtained from amniotic fluid (AF) as an alternative model more representative of what naturally happens in vivo. In our opin-ion, these hMSCs are still not influenced by differentiation stimuli and could act in a way more cor-respondent to the physiological process of adipogenesis, representing also an ethically acceptable al-ternative to totipotent human embryonic stem cells (ES). Adipocyte differentiation was monitorated following the expressions of key genes. We measured the expression levels of PPAR2, PPAR-C1, UCP-1, adipsin, and leptin genes using quantitative real-time PCR. We tested our experimental model with two different media. Understanding in vivo adipogenesis mechanisms will shed light on the pathophysiology of many diseases. 71