title: The association of human mesenchymal stem cells with BMP-7 improves bone regeneration of critical-size segmental bone defects in athymic rats.
abstract: Critical size segmental bone defects are still a major challenge in reconstructive orthopedic surgery. Transplantation of human mesenchymal stem cells (hMSC) has been proposed as an alternative to autogenous bone graft, as MSC can be expanded in vitro and induced to differentiate into bone-regenerating osteoblasts by several bone morphogenetic proteins (BMP). The aim of this study was to investigate whether the association of hMSC and BMP-7, with providing the necessary scaffold to fill the bone loss, improved bone regeneration in a rat model of critical size segmental bone defect, compared to treatment with either hMSC or BMP-7 and the matrix. In addition, we tested whether pre-treatment of hMSC with cyclic ADP-ribose (cADPR), an intracellular Ca2+ mobilizer previously shown to accelerate the in vitro expansion of hMSC (Scarfì S et al, Stem Cells, 2008), affected the osteoinductive capacity of the cells in vivo. X-ray analysis, performed 2, 10 and 16 weeks after transplantation, revealed a significantly higher score in the rats treated with hMSC and BMP-7 compared to controls, receiving either hMSC or BMP-7. Microtomography and histological analysis, performed 16weeks after transplantation, confirmed the improved bone regeneration in the animals treated with the association of hMSC and BMP-7 compared to controls. Pre-treatment with cADPR to stimulate hMSC proliferation in vitro did not affect the bone regenerating capacity of the cells in vivo. These results indicate that the association of in vitro expanded hMSC with BMP-7 provide a better osteoinductive graft compared to either hMSC or BMP-7 alone. Moreover, cADPR may be used to stimulate hMSC proliferation in vitro in order to reduce the time required to obtain a transplantable number of cells, with no adverse effect on the bone regenerating capacity of hMSC.
authors.affiliation: Hip Surgery Unit and "Livio Sciutto" Foundation, S. Corona Hospital, Pietra Ligure, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Burastero
authors.forename: Sonia
authors.initials: S
authors.lastname: Scarfì
authors.forename: Chiara
authors.initials: C
authors.lastname: Ferraris
authors.forename: Chiara
authors.initials: C
authors.lastname: Fresia
authors.forename: Nadia
authors.initials: N
authors.lastname: Sessarego
authors.forename: Floriana
authors.initials: F
authors.lastname: Fruscione
authors.forename: Francesco
authors.initials: F
authors.lastname: Monetti
authors.forename: Francesca
authors.initials: F
authors.lastname: Scarfò
authors.forename: Peter
authors.initials: P
authors.lastname: Schupbach
authors.forename: Marina
authors.initials: M
authors.lastname: Podestà
authors.forename: Guido
authors.initials: G
authors.lastname: Grappiolo
authors.forename: Elena
authors.initials: E
authors.lastname: Zocchi
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000494:pharmacology; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D055419:Bone Morphogenetic Protein 7 / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects*; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics; D051381:Rats; D011923:Rats, Nude; D014158:Transcription, Genetic / Q000187:drug effects; D014945:Wound Healing / Q000187:drug effects; D055114:X-Ray Microtomography
chemical_list: D015415:Biomarkers; D055419:Bone Morphogenetic Protein 7; D000246:Adenosine Diphosphate Ribose