S. Bahrami et al., Periosteally derived osteoblast-like cells differentiate into chondrocytesin suspension culture in agarose, ANAT REC, 259(2), 2000, pp. 124-130
Pluripotent cells from the periosteal layer adjacent to cortical bone attai
n an osteoblast-like phenotype in culture when reaching confluence in monol
ayer. It is unknown whether such newly differentiated osteoblast-like cells
preserve the chondrogenic potential characteristics for stem cells derived
from the periosteum. Primary osteoprogenitor cells derived from bovine met
acarpal periosteum were differentiated into alkaline phosphatase-positive o
steoblast-like cells by an established monolayer culture protocol. After tr
ansfer into suspension culture in agarose gels, the cells differentiated in
to chondrocytes demonstrated by the production of collagen II, but not of c
ollagen I, as well as alkaline phosphatase activity was abated. Contrarily,
with continuation of monolayer culture, the cells maintained their osteobl
ast-like phenotype and secreted large amounts of collagen I and a minor qua
ntity of collagen III and V. The alkaline phosphatase activity steadily inc
reased during the entire culture period of 2 weeks. Thus, our culture techn
iques can serve as useful tools to study mechanisms of differentiation by m
odulating the phenotypic potential of osteogenic cells. The results present
ed here support the notion that the extracellular environment strongly infl
uences the cell type and its metabolism. Anat Rec 259:124-130, 2000. (C) 20
00 Wiley-Liss, Inc.