Summary of the Rationale for Conducting the Study

When the size of a bone defect exceeds the intrinsic regenerative capacity of bone (critical-size bone defect), or in certain bone diseases where spontaneous bone healing does not occur, the use of biomaterials becomes essential for bone regeneration. For this purpose, autogenous bone alone or in combination with allografts is most commonly used. Demineralized freeze-dried bone allograft (DFDBA) contains bone morphogenetic proteins (BMPs) and exhibits osteoconductive and osteoinductive properties. Despite the widespread use of bone allografts, their handling is difficult and they lack adhesive properties, which leads to dispersion of the particles at the defect site. Fibrin glue is used in surgery as a sealant to reduce capillary and lymphatic bleeding and has also been applied in tissue engineering as a novel therapeutic approach for bone repair and regeneration. Fibrin glue forms a biocompatible porous scaffold that provides favorable conditions for cell migration and angiogenesis. It also helps prevent the dispersion of bone powder particles. In addition, fibrin can be injected in liquid form and subsequently solidifies in situ, allowing it to fill bone defects of any shape or geometry. However, due to its rapid degradation and weak mechanical properties, many researchers have combined fibrin with other materials to overcome these limitations. Emdogain is the commercial name of a synthetic enamel matrix derivative (EMD), composed mainly of amelogenin proteins, which stimulate cell proliferation and differentiation and improve the regeneration of periodontal tissues and alveolar bone. Exosomes are a subgroup of membrane-bound extracellular vesicles with sizes ranging from 30 to 150 nanometers and have recently attracted significant attention in regenerative medicine. Exosomes have been evaluated in numerous animal models for bone regeneration in defects and bone-related diseases such as osteoarthritis, osteoporosis, osteonecrosis, and inflammatory bone loss in periodontitis, demonstrating enhanced bone formation and tissue integration. Given that no study has yet compared bone regeneration using DFDBA bone powder combined with fibrin glue containing exosomes versus DFDBA bone powder combined with fibrin glue containing enamel matrix derivative (Emdogain), the present study aims to compare the effects of adding exosomes or Emdogain to DFDBA bone powder with fibrin glue on the regeneration of critical-size defects in rat calvaria.

Principal Investigator: Dr. Amir Jalal Abbasi
Start Year: 1404