Mesodermal differentiation potency of culture-expanded hMSC. Characterization of culture-expanded hMSC upon exposure to specific (A) chondrogenic, (B) osteogenic and (C) adipogenic agents, respectively. Chondrogenic, adipogenic and osteogenic differentiation potential were confirmed by means of (A) immunohistochemical staining of collagen type II fibers, (B) Von Kossa and (C) Oil Red O staining, respectively. 64 × 10 original magnification. Stainings shown are representative for at least 5 separate experiments.