fig1

Figure 1. Proliferation and differentiation capacity of adipose tissue-derived stem cells (ASCs). ASCs display a fibroblast like phenotype. Their morphology is characterized by a small cell body, containing a large round nucleus, with long and thin extensions. ASC have have high proliferation and self-renewal potential in vitro. Upon induction by specific medium, ASCs are able to differentiate into different cell lines including the adipogenic, chondrogenic and osteogenic line. According to their cell fate, ASC change their morphology by activation of certain molecular processes during the differentiation processes. This may lead to increased fat synthesis resulting in the generation of lipid droplets (white arrows; adipogenic differentiation is indicated by red droplets upon Oil-Red O staining), which will increase during adipogenesis (white asterisks), and finally merge into one large fat vacuole. During osteogenesis, ASCs secrete a collagen I-rich extracellular matrix that calcifies during the later stages of differentiation. One indicator of osteogenesis is the formation of calcification appearing red after Alizarin red staining (arrow). Chondrogenic differentiation leads to the generation of cell nodules associated with a well-organized extracellular matrix rich in collagen II and sulfated proteoglycans. These proteoglycans can be specifically detected using the stain Alcian Blue under acidic conditions (white asterisk; cross marks nuclei; arrows denote acidic mucosubstances)