title: Ectopic bone formation in rats: the importance of vascularity of the acceptor site.
abstract: Bone graft substitutes (BGS) can be fabricated by the combination of three key ingredients: (1) competent bone-forming cells, (2) a suitable framework or scaffold, and (3) the presence of biological stimulants. Although much research has been done to develop the ideal BGS, still the results are not very consistent. In view of this, the cellularity and vascularity of the recipient site are supposed to be important for the osteoinductive capacity of BGS. Therefore, we hypothesized that a muscle recipient site could favor bone formation in a cell-based BGS compared to a subcutaneous recipient site due to the higher vascularity of muscle tissue. To prove this hypothesis, 48 titanium fiber mesh implants were seeded with rat bone marrow stromal cells (RBM) and implanted subcutaneously and intramuscularly in the adductor thigh muscle of rats. The amount of bone formation after 1, 3 and 6 weeks was evaluated by histology and histomorphometry as well as by calcium content. Analysis revealed that the bone formation increased during implantation. However, bone formation did not exceed 12% of the implant surface, both for the intramuscular and subcutaneous recipient site. Also, no significant differences in bone amount between these two sites existed. Consequently, our hypothesis could not be confirmed.
authors.affiliation: Department of Plastic Surgery, University Medical Center Nijmegen 305, P.O. Box 9101, Nijmegen 6500 HB, The Netherlands. hartman@nvpc.nl
authors.forename: Ed H M
authors.initials: EH
authors.lastname: Hartman
authors.forename: Johan W M
authors.initials: JW
authors.lastname: Vehof
authors.forename: J E
authors.initials: JE
authors.lastname: de Ruijter
authors.forename: Paul H M
authors.initials: PH
authors.lastname: Spauwen
authors.forename: John A
authors.initials: JA
authors.lastname: Jansen
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001846:Bone Development; D001854:Bone Marrow Cells / Q000378:metabolism; D018786:Bone Substitutes; D002118:Calcium / Q000378:metabolism; D017102:Fracture Healing; D050723:Fractures, Bone / Q000628:therapy*; D020007:Implants, Experimental; D008297:Male; D008856:Microscopy, Fluorescence; D009132:Muscles / Q000378:metabolism; D018919:Neovascularization, Physiologic; D010011:Osteocytes / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors; D023822:Tissue Engineering; D014025:Titanium / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D014025:Titanium; D002118:Calcium