Donor variation in the growth properties and osteogenic potential of humanmarrow stromal cells

Human marrow stromal cells (MSCs) were isolated from posterior illiac crest marrow aspirates obtained from 17 healthy donors, ages 19-45 years, with n o apparent physical disability. First passage hMSCs exhibited growth rates in vitro that varied up to 12-fold between donors. No correlation between g rowth rate and the age or gender of the donor was evident (P less than or e qual to 0.05). When hMSCs were cultured without passage for eight days (sub confluent cultures) or 22 days (confluent cultures) in the absence of any o steogenic agonists, levels of alkaline phosphatase enzyme activity varied 4 0-fold and 10-fold, respectively, between donors. When exposed to osteo-ind uctive media, donor populations also showed dramatic differences in levels of bone-specific gene induction. Collectively, these data demonstrate that hMSC cultures are composed of a heterogeneous mixture of cells at various s tages of differentiation and with distinct osteogenic potentials. Differenc es in both growth rate and ALP activity were evident in hMSC cultures Estab lished from multiple aspirates obtained over a six month period from the sa me donors. Therefore, it appears that cellular heterogeneity produced by th e method of harvest is propagated within and among different donor populati ons during culture expansion in vitro. J. Cell. Biochem. 75:424-436, 1999. (C) 1999 Wiley-Liss, Inc.