Summary
BIA, a Bone Inducing Agent extracted from a cultured human osteosarcoma cell line
(Saos–2), is highly osteoinductive in the skeletal muscle of athymic mice and promotes
early osseous union of stabilized femoral non-unions in rats. To evaluate its effect
in dogs, ten milligrams of BIA mixed with an equal amount of pure bovine collagen
type I was compared with 20 mg of bovine collagen alone, a gelatin capsule alone,
and fresh autogenous cancellous graft, after orthotopic and heterotopic implantation
in Beagles.
For osteoinductive bioassays, each implant was placed in the latissimus dorsi muscle
of five Beagles for six weeks. Bone formation was evaluated by thoracic radiographs
every two weeks and by high detail radiographs and histology six weeks after implantation.
To evaluate the effects of BIA after orthotopic implantation, four cortical defects
were created in each left femur of four Beagles. One defect on each femur was randomly
filled with BIA plus collagen, collagen alone, a gelatin capsule alone, or autogenous
cancellous graft. Radiographic evaluation of the femurs was performed every two weeks
for eight weeks. Healing of the defects was assessed with high detail radiographs,
dual energy X-ray absorptiometry, histology and histomorphometry eight weeks after
implantation.
Ten mg of BIA did not induce bone formation six weeks after heterotopic implantation
and did not promote bone healing after orthotopic implantation in the dogs. The discrepancy
between these results and those obtained in rodents may be related to immunogenic
factors or to the dose of BIA used in this study.
BIA, a Bone Inducing Agent extracted from a cultured osteosarcoma cell line is highly
osteoinductive in rodents. BIA was evaluated and compared with autogenous cancellous
bone graft and bovine collagen after orthotopic and heterotopic implantation in Beagles.
Each implant was placed in the latissimus dorsi muscle of five Beagles and in femoral
cortical defects of four Beagles. Bone formation was evaluated by radiography, dual
energy X-ray absorptiometry, histology and histo-morphometry. BIA did not induce bone
formation after heterotopic implantation and did not promote bone healing after orthotopic
implantation in dogs.
Keywords
Osteoinduction - bone inducing agent - osteosarcoma
