Assessment of bovine biomaterials containing bone morphogenetic proteins bound to absorbable hydroxyapatite in rabbit segmental bone defects

Evelyn Hasegawa Gonçalves Caporali,José Mauro Granjeiro,Tânia M Cestari,José Morceli,Sheila Canevese Rahal,Mariana A Correa,Maria Jaqueline Mamprim,Rumio Taga

doi:10.1590/s0102-86502006000600003

Abstract

To evaluate the osteo-regenerative capacity of two proprietary bone grafting materials, using a segmental defect model in both radial diaphyses of rabbits. The right defect was filled with pooled bone morphogenetic proteins (pBMPs) bound to absorbable ultrathin powdered hydroxyapatite (HA) mixed with inorganic and demineralized bone matrix and bone-derived collagen, derived from bovine bone (Group A). The left defect was filled with bovine demineralized bone matrix and pBMPs bound to absorbable ultrathin powdered HA (Group B). In both groups, an absorbable membrane of demineralized bovine cortical was used to retain the biomaterials in the bone defects, and to guide the tissue regeneration. The rabbits were euthanized 30, 90 and 150 days after surgery. Radiographic, tomographic and histologic evaluations were carried out on all specimens. At 30 days, the demineralized cortical bone cover was totally resorbed in both groups. HA was totally resorbed from Group A defects, whereas HA persisted in Group B defects. A prominent foreign body reaction was evident with both products, more pronounced in sections from Group B. At 90 days, the defects in Group B exhibited more new bone than Group A. However, at 150 days after surgery, neither treatment had stimulated complete repair of the defect. The partial bone healing of the segmental defect occurred with low or none performance of the biomaterials tested.

Highlights

Autografts and allografts are the traditional options for treatment of larger bone defects[1], their use is associated with several disadvantages
Costa Filho et al.[12] testing a pool of Bovine purified BMP (bBMP) bound to a similar absorbable hydroxyapatite mixed with inorganic bovine bone in cylindrical titanium prototypes introduced into tibiae of rabbits, concluded that the pool of bBMPs containing other bone non-collagenous proteins had a inhibitory effect on osteogenesis
Brandão et al.[22] evaluating the same hydroxyapatite, mixed or not with pooled bone morphogenetic proteins (pBMPs) implanted in rat alveolar wounds, achieved delay in wound healing in both groups, suggesting an absence of osteogenic properties in these materials

Summary

Introduction

Autografts and allografts are the traditional options for treatment of larger bone defects[1], their use is associated with several disadvantages. Allograft and xenograft bone substitutes have been studied to overcome the risks associated to autogenous bone, but their use is complicated by issues such as immunogenicity and consequent rejection, graft sequestration and infection; and the potential for disease transmission[1,2]. To overcome these limitations, considerable research has been directed towards developing clinically viable bone substitutes that are biocompatible, resorbable, and easy to handle, with physical and chemical properties similar to that of cancellous bone, free of pathological agents and cost-effective[2]. The hypothesis addressed by the study is that the graft materials will exhibit similar osteo-regenerative effects

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Results

Conclusion