Bone morphogenetic protein induces bone in the squirrel monkey, but bone matrix does not.

Demineralized bone matrix (DBM) reproducibly induces extraskeletal bone formation in rodents, but its effects in dogs and primates are negative or uncertain. In previous studies on the squirrel monkey, DBM did not induce bone, although the same implants were effective in nude rats. In the present study, the DBM was augmented with recombinant human bone morphogenetic protein-2 (BMP-2). Bone was formed in 10 of 12 monkeys, as verified by histology and calcium content. However, in 4 monkeys, the induced bone mass appeared smaller than the original implant. DBM controls induced microscopic amounts of bone in 2 out of 10 monkeys. In the nude rats, all DBM controls and augmented implants induced bone. The difficulties in achieving bone induction in higher animals may be overcome, at least partially, by using a higher concentration of the inductive protein than is present in DBM.