Autologous Porcine Bone Marrow Mesenchymal Cells for Reconstruction of a Resorbed Alveolar Bone: A Preclinical Model in Mini-Pigs

Regeneration of atrophied alveolar bone prior to insertion of dental implants is a major challenge for oral and maxillofacial surgery. It has been reported that Bone Marrow (BM) derived Mesenchymal Stromal Cells (MSC) retain therapeutic potential for bone regeneration. In the present study, a preclinical mini-pig model simulating the clinical setting was established in order to evaluate the efficacy of autologous MSC for mandible regeneration. Under general anaesthesia, BM aspirates were collected from tibia of mini-pigs (n = 5) and MSC were isolated, characterized and expanded. At the same time, a narrow alveolar ridge was simultaneously created by bilateral extraction of two premolar teeth and removal of the buccal bone in order to simulate the pathological situation in humans. After ex vivo expansion, cells were delivered fresh to the surgical operating room and seeded on Biphasic Calcium Phosphate (BCP) granules for 1 hour followed by implantation into the simulated alveolar defects in one pig. The surgical defects were closed with sutures and left to heal for eight weeks. A bone biopsy was taken and dental implants were placed in the newly formed bone. The bone biopsy taken during the procedure showed mineralized bone containing substantial amount of new bone with BCP granules embedded in osteoid tissues and dispersed throughout the newly formed bone matrix. The data demonstrate the osteogenic potential of autologous MSC combined with BCP, providing crucial pre-clinical information in a large animal aimed at the reconstruction of resorbed alveolar bone.