Bone morphogenetic proteins in human bone regeneration

Recently, the first clinical reports on bone regeneration by two recombinant human bone morphogenetic proteins (rhBMPs), BMP-2 and BMP-7 (also named osteogenic protein-1, OP-1) have been published (1-4). Although both BMPs were able to support bone regeneration, a significant variation in individual response was observed with both proteins. Animal studies and laboratory experiments reveal a number of conditions that influence the osteoinductivity of BMP, such as BMP concentration, carrier properties and influence of local and systemic growth factors and hormones. In this paper, these studies and the clinical reports are reviewed, and the conditions that modulate the BMP-dependent osteoinduction are discussed. The information may provide clues as to how the performance of recombinant human BMP as bone-graft substitute in humans can be improved.