Transforming growth factor-beta 1 adsorbed to tricalciumphosphate coated implants increases peri-implant bone remodeling

Increasing experimental interest has emerged for the use of growth factors to stimulate bone healing and bone formation in various clinical situations . We and others have demonstrated that recombinant human transforming growt h factor-beta1 (rhTGF-beta1) adsorbed onto tricalcium phosphate (TCP)-coate d implants can improve mechanical fixation and bone ongrowth. The present s tudy evaluated bone remodeling in newly formed bone and adjacent trabecular bone around TCP-coated implants with and without rhTGF-beta1 adsorption. U nloaded cylindrical grit-blasted titanium alloy implants coated with TCP we re inserted bilaterally into the femoral condyles of 10 skeletally mature m ongrel dogs. The implants were initially surrounded by a 2 mm gap. Implants with 0.3 mug rhTGF-beta1 were compared with implants without growth factor . The dogs were sacrificed after six weeks. Bone remodeling was evaluated b y histomorphometry on Goldner-stained undecalcified sections. The bone volu me in the gap was increased significantly from 17.6% in the control group t o 25.6% in the rhTGF-beta1 group (p = 0.03). Also bone surface was increase d in the rhTGF-beta1 group. The osteoclast covered surfaces were increased from 3.6% in the control group to 5.9% in the rhTGF-beta1 group (p = 0.02). In the surrounding trabecular bone no significant changes in bone remodeli ng parameters was demonstrated. This study suggests that rhTGF-beta1 adsorb ed onto TCP-ceramic coated implants accelerates repair activity in the newl y formed bone close to the implant, but it does not seem to influence bone remodeling in preexisting bone at a greater distance from the implant. (C) 2000 Elsevier Science Ltd. All rights reserved.