title: Comparison of in vitro mineralization by murine embryonic and adult stem cells cultured in an osteogenic medium.
abstract: Nearly half a million bone-grafting procedures occurred in the United States in the year 2000. Tissue-engineered bone substitutes may mitigate difficulties associated with current grafting options. Embryonic stem cells (ESCs) could be a potential cell source for bone substitutes; however, direct comparisons between ESCs and other cell sources are lacking. Here we provide a direct, long-term, in vitro comparison of mineralization processes in adult, marrow-derived, mesenchymal stem cells (MSCs) and ESCs from the 129/Sv+c/+p mouse strain. MSCs were observed to grow at a slower rate than ESCs. MSCs expressed seven times more alkaline phosphatase (AP) per cell than did ESCs and immediately showed type I collagen and osteocalcin production. ESCs also produced type I collagen and osteocalcin, but production was delayed. Mineral deposition by ESCs was nearly 50 times higher than by MSCs. Spectroscopic analysis showed the calcium-to-phosphorus ratio (Ca:P) of the ESC mineral (1.26:1) to be significantly higher than that of the MSCs (0.29:1), but still 25% lower than hydroxyapatite (1.67:1). Addition of basic fibroblast growth factor significantly inhibited AP expression, mineral deposition, and Ca:P ratios in MSCs and had little effect on ESCs. These functional characteristics may assist with cell selection for purposes of bone tissue engineering.
authors.affiliation: Department of Biomedical Engineering, Tulane University, New Orleans, Louisiana, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Shimko
authors.forename: Chris A
authors.initials: CA
authors.lastname: Burks
authors.forename: Kay C
authors.initials: KC
authors.lastname: Dee
authors.forename: Eric A
authors.initials: EA
authors.lastname: Nauman
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D018786:Bone Substitutes; D002113:Calcification, Physiologic / Q000187:drug effects / Q000502:physiology*; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology*; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D018786:Bone Substitutes; D016222:Fibroblast Growth Factor 2