Thrombin Peptide TP508 Enhances Bone Formation in Rabbit Maxillary Sinus

Objectives: TP508 thrombin based peptide (Chrysalin™) has been shown to increase expression of genes involved in osteoblastic differentiation, matrix synthesis and angiogenesis, and may act to protect the initial clot formation onto bone graft particles. Anorganic bovine bone (ABB) is a bone replacement graft that is both biocompatible and has osteoconductive properties. The aim of this project was to evaluate the effect on new bone formation with ABB + TP508 compared to ABB and collagen sponge controls in the maxillary sinuses of rabbits. Methods: 24 female New Zealand white rabbits received bilateral maxillary sinus augmentation with standardized amounts of ABB + 20ug TP508 (Group A), ABB + 100ug TP508 (Group B), ABB alone, or collagen sponge alone. Animals were sacrificed at 2 and 5 weeks and block sections of each maxillary sinus were prepared for histometric evaluation. Results: For all groups, the percentage of the carrier grafted bone decreased from 2 to 5 weeks, and new bone was evident at 2 weeks. All groups except collagen sponge controls had statistically significant more new bone formation at 5 weeks vs. 2 weeks. These 2 to 5 week increases were as follows: 3.6-10.8% ABB alone, 14.0-26.8% Group A, and 11.7-21.2% Group B. Groups A and B had statistically greater bone formation compared to the ABB alone group at both 2 and 5 weeks. Group A had 5.6% more new bone (p<0.05) than Group B bone formation at 5 weeks. Conclusions: TP508 peptide when used in combination with ABB can enhance new bone formation in the maxillary sinus and appears to have a stimulatory osteoinductive type effect on an otherwise osteoconductive bone graft.

Supported by Chrysalis Biotechnology, Inc, Orthologic, Inc., and Research and Grants Committee of the Louisiana State University School of Dentistry Grant Number: PP0203