FTY720 administration results in a M2 associated immunoregulatory effect that positively influences the outcome of alveolar bone repair outcome in mice.

The alveolar bone repair process may be influenced by multiple local and systemic factors, which include immune system cells and mediators. Macrophages allegedly play important roles in the repair process, and the transition of an initial inflammatory M1 profile into a pro-reparative M2 profile theoretically contributes to a favorable repair outcome. In this context, considering immunoregulatory molecules as potential targets for improving bone repair, this study evaluated the role of the immunoregulatory molecule FTY720, previously described to favor the development of the M2 phenotype, in the process of alveolar bone healing in C57Bl/6 (WT) mice. Experimental groups submitted to tooth extraction and maintained under control conditions or treated with FTY720 were evaluated by microtomographic (µCT), histomorphometric, immunohistochemical and molecular analysis to characterize healing and host response features at 0, 1, 3, 7 and 14 days. Our results demonstrated that the FTY720 group presented higher bone tissue density, higher bone tissue volume, greater tissue volume fraction, greater number and thickness of trabeculae and a higher number of osteoblasts and osteoclasts than the control group. Accordingly, the bone markers BMP2, BMP7, ALPL, SOST and RANK mRNA expressions increased in the FTY720 treated group. Furthermore, the levels of FIZZ, ARG2 and IL-10 mRNA increased in the FTY720 group together with the presence of CD206+ cells, suggesting that the boost of bone formation mediated by FTY720 involves an increased polarization and activity of M2 macrophages in healing sites. Thus, our results demonstrate that FTY720 favored the process of alveolar bone repair, probably trough a strengthened M2 response, associated with an increased expression of markers osteogenic differentiation and activity markers. Immunoregulatory strategies based in the modulation of macrophage polarization profile can comprise effective tools to improve the bone repair process.

Oral health condition in cancer patients under bisphosphonate therapy.

OBJECTIVES: To investigate the association of oral health condition with the occurrence of medication-related osteonecrosis of the jaw (MRONJ) in a cancer population. METHODS: A multicenter cross-sectional study was conducted with cancer patients exposed to bisphosphonates for at least 7 months. Dental and periodontal conditions were assessed by epidemiological indices. RESULTS: The sample consisted of 80 patients under bisphosphonate therapy, nine of which were allocated to group 1 (with MRONJ) and 71 to group 2 (without MRONJ). Osteonecrosis cases presented 19 decayed, missing, and filled teeth on average. Moderate gingival inflammation was noted in both groups and together with severe inflammation exceeded 50% of the groups. The presence of dental calculus was detected in about half of the individuals in both groups. Shallow periodontal pockets were detected in about 25% of both groups. Deep periodontal pockets were more prevalent among patients with osteonecrosis. Regular oral hygiene was detected in approximately 25% of individuals in both groups. There was a strong positive correlation between the clinical staging of osteonecrosis and decayed, missing, and filled teeth index (DMFTI). CONCLUSIONS: Patients had a poor oral health condition. All but one osteonecrosis case had no previous history of tooth extraction; oral infections seemed to play a major role in the development of bone necrosis. Advanced osteonecrosis stages were associated with a higher DMFTI.