title: Carrier dependent cell differentiation of bone morphogenetic protein-2 induced osteogenesis and chondrogenesis during the early implantation stage in rats.
abstract: To evaluate the osteoinductive effects of recombinant human bone morphogenetic protein (rhBMP)-2 during the early stages of rat ectopic bone formation, we prepared two distinct carriers. Two carriers, insoluble bone matrix (IBM) and fibrous glass membrane (FGM) were combined with rhBMP-2 and implanted into the backs of rats to evaluate the osteoinductive effects of the two rhBMP-2 carrier systems. Insoluble bone matrix particle size was 320 to 620 microm. Fibrous glass membrane was constructed from unwoven glass fibers 1 microm in diameter. Alkaline phosphatase (ALP) activity and type II collagen were detected in IBM/rhBMP-2 at 5 days postimplantation. Calcium (Ca) was also detected in IBM/rhBMP-2 at 7 and 9 days postimplantation. In contrast, ALP and type II collagen were detected in FGM/rhBMP-2 at 7 days. Calcium was undetected, indicating that the bone formation in IBM/rhBMP-2 proceeded faster than in FGM/rhBMP-2 during the early stage of BMP-induced osteogenesis. In addition, mRNA expression level of KDR, a receptor for vascular endothelial growth factor, was also increased in IBM/rhBMP-2. To investigate the in vivo release profile of rhBMP-2, iodine 125 ((125)I)-labeled BMP-2-incorporating IBM and FGM implants were inserted into the back subcutis of mice. More than 60% of the rhBMP-2 was released from the IBM/rhBMP-2 carrier within 1 day after implantation, whereas 50% of the rhBMP-2 was released from the FGM/rhBMP-2 10 days postimplantation. These results indicated that osteo- and chondrogenesis depends highly upon the geometry of the carrier and the in situ retention of rhBMP-2 during the early stage of rhBMP-2 induced bone formation.
authors.affiliation: Department of Oral Health Science, Graduate School of Dental Medicine, Hokkaido University, N-13, W-7, Kita-ku, Sapporo 060-8586, Japan. htakita@den.hokudai.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Takita
authors.forename: J W M
authors.initials: JW
authors.lastname: Vehof
authors.forename: J A
authors.initials: JA
authors.lastname: Jansen
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Tabata
authors.forename: M
authors.initials: M
authors.lastname: Tamura
authors.forename: Y
authors.initials: Y
authors.lastname: Kuboki
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001857:Bone Matrix / Q000737:chemistry / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D020219:Chondrogenesis / Q000502:physiology*; D004337:Drug Carriers; D005898:Glass / Q000737:chemistry; D006801:Humans; D007457:Iodine Radioisotopes / Q000378:metabolism; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D010316:Particle Size; D019736:Prostheses and Implants; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism
chemical_list: C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D004337:Drug Carriers; D007457:Iodine Radioisotopes; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D015675:Osteocalcin; D040301:Vascular Endothelial Growth Factor Receptor-2; D000469:Alkaline Phosphatase; D002118:Calcium