BOVINE BONE MORPHOGENETIC PROTEIN (BBMP NCP)-INDUCED REPAIR OF SKULL TREPHINE DEFECTS IN PIGS/

Bovine bone morphogenetic protein and associated noncollagenous protei ns (bBMP/NCP) were implanted in skull trephine defects, 14 and 22 mm i n diameter, in adult minipigs. The defects were larger than the critic al size for repair of cranial bones in pigs observed for a period of s ix to 16 weeks. The trephines were placed either in the nasal bone at eye level, or in the frontal bone. In minipigs the repair was more adv anced in trephines in the frontal bone than in the nasal region, but w as incomplete in either bone bed. As in dogs, implants of bBMP/NCP in heterotopic sites were resorbed before a competent cell population cou ld respond. Serum anti-BMP antibody was elevated. The IgG levels of th e antibody titer showed a clearcut dose-response; the level was signif icantly higher in one pig with implants of 85 mg of bBMP/NCP proteins in a frontal bone trephine.