PTH Effects on Bone Healing in Calvaria Bone Allograft Model

Introduction: The establishment of new therapeutic approaches for tissue repair and regeneration can be accelerated if adequate technologies for monitoring the repair process are developed. In craniomaxillofacial surgery, 96,000 bone graft procedures are performed each year to treat bone loss due to trauma or disease. Alas, autologous bone grafts are not always available, and additional surgery must be performed for its harvest. Alternatively, there is a large potential supply of craniofacial allografts composed of nonvital bone. However, these grafts often fail to integrate with host bone due to formation of scar tissue. Recently, it was shown that daily teriparatide (recombinant human parathyroid hormone, PTH) treatment enhances integration of devitalized allograft in long bones and inhibits scar formation. We hypothesized that PTH treatment induces integration of allografts also in cranial membranous bones via several mechanisms as depicted on Diagram 1: 1. Enhanced homing of MSCs to the site of injury; 2. Enhanced differentiation of MSCs to osteoprogenitors; 3. Modulation of the vasculogenesis in the defect proximity decreases the abundance of mast cells, thus leading to more efficient bone formation on the expanse of fibrous tissue.