Periodontal regeneration using ex vivo autologous stem cells engineered to express the BMP-2 gene: an alternative to alveolaplasty

The regeneration of the periodontal attachment apparatus remains clinically challenging because of the involvement of three tissue types and the complexity of their relationship. Human recombinant bone morphogenic protein-2 (rhBMP-2) can accelerate the regeneration of bone and cementum and the insertion of periodontal ligament fibers but may lead to a deranged periodontal relationship, ankylosis and root resorption. This study evaluated a novel approach to regeneration of the periodontal attachment apparatus using a combination of ex vivo autologous bone marrow mesenchymal stem cells (MSCs) engineered by replication-defective adenovirus to express the BMP-2 gene and Pluronic F127 (PF127). Twenty-four periodontal defects were surgically created in 12 New Zealand white rabbits and randomly assigned to three experimental groups with MSCs: the advBMP-2 group; the adv beta gal group; the MSC group and one control group: PF127 only. The regenerated periodontal attachment apparatus was assessed histologically and the total regenerated bone volume was calculated from three-dimensional computed tomography analysis. This approach regenerated not only cementum with Sharpey's fiber insertion, but also statistically significant quantities of bone, re-establishing a more normal relationship among the components of the regenerated periodontal attachment apparatus, which is beneficial for the maintenance of periodontal health. Ex vivo gene transfer using stem cells as vectors may provide an advantage of slower BMP-2 release, increasing cementogenesis. There is regeneration of the periodontal attachment apparatus, whereas direct usage of the protein (rhBMP-2) yields unhinged periodontal relationship. Thus, this approach may represent an alternative means for periodontal alveolar bone graft in clinical settings.