(P 197) Hypoxia Exerts Differential Effects on the Chondrogenic and Osteogenic Differentiation of Human Adipose-Derived Mesenchymal Stem Cells

• Published in: Tissue engineering. Part A 2008-05, Vol.14 (5), p.861-861
• Main Authors: Merceron, C, Vinatier, C, Masson, M, Guigand, L, Amiaud, J, Cherel, Y, Gatius, M, Weiss, P, Guicheux, J
• Format: Article
• Language: English
• ISSN: 1937-3341; 1937-335X

Human adipose tissue-derived stem cells (hATSC) have been contemplated as reparative cells for cartilage engineering. Chondrogenic differentiation of hATSC can be induced by an enriched culture medium and a three dimensional environment. Given that bone is vascularized and cartilage not, oxygen tension has been suggested as a regulatory factor for osteo-chondrogenic differentiation. Our work aimed at determining whether hypoxia affects the osteo-chondrogenic potential of hATSC. HATSC were cultured in chondrogenic or osteogenic medium for 30 days, in pellets or monolayers, and under 5% or 20% oxygen tension. Cell differentiation was monitored by real-time PCR (COL2A1, aggrecan and osteocalcin). The chondrogenic differentiation was further evaluated by Alcian Blue and immunohistological staining for glycosaminoglycans (GAG) and type II collagen respectively. The osteogenic differentiation was also assessed by the staining of mineralized matrix (Alizarin Red) and measurement of alkaline phosphatase activity (ALP). The expression of chondrogenic markers was up-regulated when hATSC were exposed to hypoxia in chondrogenic medium. Conversely, osteocalcin expression, mineralization and ALP activity were severely reduced under hypoxic condition even in the presence of osteogenic medium. Our data strongly suggest that hypoxia favors the chondrogenic differentiation of hATSC as evidenced by the expression of the chondrogenic markers, whereas it could alter their osteogenic potential. Our results highlight the differential regulatory role of hypoxia on the chondrogenic and osteogenic differentiation process of hATSC. These data could help us exploit the potential of tissue engineering and stem cells to replace or restore the function of osteoarticular tissues.