Osteoinduction by demineralised bone

Bone contains several growth factors, including bone morphogenetic proteins (BMPs), transforming growth factor beta (TGF-beta), insulin-like growth fa ctors I and II (IGF-I and IGF-II), platelet derived growth factor (PDGF) an d basic and acidic fibroblast growth factor (bFGF and aFGF). The BMPs are t he only factors known to provoke bone formation heterotopically by making u ndifferentiated formation heterotopically by making undifferentiated mesenc hymal cells differentiate into osteoblasts (osteoinduction). Much of our kn owledge of osteoinduction derives from studies in rodents of heterotopicall y implanted demineralised bone which contains various growth factors, inclu ding BMPs. This model has been used to examine the effect on osteoinduction of different factors, including the type of host soft tissue, age and spec ies of donor and recipients, demineralisation procedure, storage and steril isation procedures, experimental diabetes, dietary factors, hormones, growt h factors, caffeine, biphosphonates, indomethacin and biomaterials. Deminer alised bone enhances bone formation experimentally in various animal models , including cranio-maxillofacial reconstructions, healing of diaphyseal def ects, and spinal fusion; demineralised bone has also been used in a limited way clinically. However, sufficient osteoinduction in humans may require a higher concentration of BMPs and other growth factors than those found in demineralised bone.