Application of BMP-Bone Cement and FGF-Gel on Periodontal Tissue Regeneration in Nonhuman Primates.

The ultimate challenge of tissue engineering research is the translation of experimental knowledge into clinical application. In the preclinical testing phase of any new therapy, animal models remain the gold standard. Therefore, the methodological choice of a suitable model is critical to meet the requirements for a safe clinical application of the developed treatment. For instance, we have shown in rats that the application of calcium phosphate cement (CPC)/propylene glycol alginate (PGA) with bone morphogenetic protein (BMP)-2 or fibroblast growth factor (FGF)-2 resulted in the regeneration of periodontal defects. However, it is debated whether using small models form a predictive method for translation to larger species. At the same time, the 3R framework is encouraged as guiding principles of the ethical use of animal testing. Therefore, based on the successful rat study, the objective of this study was to further investigate the periodontal regenerative efficacy of the CPC/BMP and PGA/FGF system in a periodontal defect model with a low number of nonhuman primates (NHPs). Three Macaca fascicularis-overstocked from breeding for other purposes-were used (reuse of animals and appropriateness of the experimental animal species according to 3R framework). Three-wall periodontal defects were surgically created in the mandible. In total, 10 defects were created and distributed over two groups: (1) control group: PGA+CPC (n = 5) and (2) experimental group: PGA/FGF+CPC/BMP (n = 5). After 3 months, tissue regeneration was evaluated by histomorphometry and radiographic measurements. Data showed that epithelial downgrowth, cementum, and ligament regeneration were significantly enhanced in the experimental group compared with the control group (n = 5; p = 0.013, p = 0.028, and p = 0.018, respectively). However, the amount of newly formed bone did not differ (p = 0.146). Overall, as a translational proof-of-principle study, the hybrid periodontal regenerative method of CPC/BMP+PGA/FGF promoted periodontal regeneration in NHPs. This study warrants the application of CPC/BMP/PGA/FGF in clinical trials.