title: In vivo bone formation following transplantation of human adipose-derived stromal cells that are not differentiated osteogenically.
abstract: A number of studies have shown in vivo bone regeneration by transplantation of osteogenic cells differentiated in vitro from adipose-derived stromal cells (ADSCs). However, the in vitro osteogenic differentiation process requires an additional culture period, and the dexamethasone that is generally used in the process may be cytotoxic. Here, we tested the hypothesis that ADSCs that are not differentiated osteogenically in vitro prior to transplantation would extensively regenerate bone in vivo when exogenous bone morphogenetic protein-2 (BMP-2) is delivered to the transplantation site. We fabricated a poly(dl-lactic-co-glycolic acid)/hydroxyapatite (PLGA/HA) composite scaffold with osteoactive HA that is highly exposed on the scaffold surface. This scaffold was able to release BMP-2 over a 4-week period in vitro. Human ADSCs cultured on BMP-2-loaded PLGA/HA scaffolds for 2 weeks differentiated toward osteogenic cells expressing alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) mRNA, while cells on PLGA/HA scaffolds without BMP-2 expressed only ALP. To study in vivo bone formation, PLGA/HA scaffolds (group 1), BMP-2-loaded PLGA/HA scaffolds (group 2), undifferentiated ADSCs seeded on PLGA/HA scaffolds (group 3), and undifferentiated ADSCs seeded on BMP-2-loaded PLGA/HA scaffolds (group 4) were implanted into dorsal, subcutaneous spaces of athymic mice. Eight weeks after implantation, group 4 exhibited a 25-fold greater bone formation area and 5-fold higher calcium deposition than group 3. Bone regeneration by transplanted human ADSCs in group 4 was confirmed by expression of human-specific osteoblastic genes, ALP, collagen type I, OPN, OCN, and bone sialoprotein, while group 3 expressed much lower levels of collagen type I and OPN mRNA only. This study demonstrates the feasibility of extensive in vivo bone regeneration by transplantation of ADSCs without prior in vitro osteogenic differentiation, and that a PLGA/HA composite BMP-2 delivery system stimulates bone regeneration following transplantation of undifferentiated human ADSCs.
authors.affiliation: Graduate School of Life Science and Biotechnology, Pochon CHA University & CHA Stem Cell Institute, Gangnam-gu, Seoul, Korea.
authors.forename: Oju
authors.initials: O
authors.lastname: Jeon
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Rhie
authors.forename: Il-Kuen
authors.initials: IK
authors.lastname: Kwon
authors.forename: Jae-Hwan
authors.initials: JH
authors.lastname: Kim
authors.forename: Byung-Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Soo-Hong
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation; D017690:Cell Transplantation; D006224:Cricetinae; D003412:Cricetulus; D017886:Durapatite / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005786:Gene Expression Regulation; D006016:Glycolates / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D019344:Lactic Acid; D051379:Mice; D008819:Mice, Nude; D010012:Osteogenesis / Q000235:genetics; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D019919:Prosthesis Implantation; D017154:Stromal Cells / Q000166:cytology* / Q000637:transplantation*; D054457:Tissue Scaffolds; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D006016:Glycolates; D016212:Transforming Growth Factor beta; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D017886:Durapatite; D002118:Calcium