Alterations of bone proteins in medication-related osteonecrosis of the jaw

Background: Changes in the protein pattern of osteoblastic lineage cells from the alveolar bone during medication-related osteonecrosis of the jaw have rarely been investigated. This lack of information is partly due to the limited availability of healthy samples and the lack of human alveolar bone cell lines for research. The aim of the present study was to investigate bone proteins collagen 1, RUNX2 and RANKL in vivo and in vitro. Furthermore, we established the necessary cell lines of osteoblastic lineage cells from the alveolar bone. Methods: We used immunohistochemistry to describe the protein pattern in vivo. For cell culture, osteoblastic lineage cells from the alveolar bone were treated with zoledronate or denosumab and analyzed by immunocytochemistry and western blots. Results: Collagen 1 is decreased in vivo in patients with MRONJ and in vitro by influence of denosumab. Zoledronate is able to reduce RUNX2 in vitro. While RANKL is not significant affected in vivo and in vitro. Conclusions: The results of the present study will help us elucidate the cellular mechanisms of medication-related osteonecrosis of the jaw. Although culture of osteoblastic lineage cells from the alveolar bone with zoledronate and denosumab significantly altered the protein pattern, future research is needed to examine the effects of bone scaffolds, biofilms and more cell types mimicking in vivo conditions.