IADR Abstract Archives
Oral Fibroblast's Critical Role in Prevention and Treatment of MRONJ
Objectives: Medication-related osteonecrosis of the jaw (MRONJ) is a severe complication that follows tooth extraction in oncologic patients receiving Zoledronic acid (ZA). While the mechanism in which ZA influences Osteoclasts is well known, the influence of ZA on Osteoblasts (OBs) differentiation and on oral mucosa hasn't been investigated thoroughly. Our aim was to investigate the interaction between soft tissue cells (STCs) and OBs after ZA administration.
Methods: XTT proliferation assay was used to determine the ZA working concentration. STCs were represented by primary oral fibroblasts from three mucosal sites - PDL, masticatory and lining mucosa, and keratinocytes by HaCat cells. The conditioned media (CM) from all STCs was collected and served as secretome: CMFibro and CMHaCat.
Bone Marrow and PDL mesenchymal stem cells (MSCs) were cultured in osteogenic medium (OS). 5 μM ZA solution was added with and without STCs secretome and differentiation was evaluated using Alkaline Phosphatase, Alizarine Red and Von Kossa staining. Proteomic analysis was used to further investigate the difference in the content between CMFibro and CMHaCat.
Results: Compared to MSCs cultured in OS, adding STCs secretome had no influence on OBs differentiation. However, addition of fresh 5 μM ZA solution with and without CMHaCat decreased OBs differentiation by at least 50%. Addition of CMFibro obtained from all fibroblasts, with fresh 5 μM ZA solution, enabled almost the same differentiation as in OS group. Proteomic analysis revealed the exclusive presence of specific proteins in CMFibro that participate in OBs differentiation.
Conclusions: ZA decreased OBs differentiation and this effect was shown to be reversed by the addition of CMFibro. A possible mechanism of action may be the secretion of pro-osteogenic proteins by oral fibroblasts. In the future, this finding can be translated into clinical procedures, using connective tissue graft to seal an extraction socket in patients receiving ZA.
Methods: XTT proliferation assay was used to determine the ZA working concentration. STCs were represented by primary oral fibroblasts from three mucosal sites - PDL, masticatory and lining mucosa, and keratinocytes by HaCat cells. The conditioned media (CM) from all STCs was collected and served as secretome: CMFibro and CMHaCat.
Bone Marrow and PDL mesenchymal stem cells (MSCs) were cultured in osteogenic medium (OS). 5 μM ZA solution was added with and without STCs secretome and differentiation was evaluated using Alkaline Phosphatase, Alizarine Red and Von Kossa staining. Proteomic analysis was used to further investigate the difference in the content between CMFibro and CMHaCat.
Results: Compared to MSCs cultured in OS, adding STCs secretome had no influence on OBs differentiation. However, addition of fresh 5 μM ZA solution with and without CMHaCat decreased OBs differentiation by at least 50%. Addition of CMFibro obtained from all fibroblasts, with fresh 5 μM ZA solution, enabled almost the same differentiation as in OS group. Proteomic analysis revealed the exclusive presence of specific proteins in CMFibro that participate in OBs differentiation.
Conclusions: ZA decreased OBs differentiation and this effect was shown to be reversed by the addition of CMFibro. A possible mechanism of action may be the secretion of pro-osteogenic proteins by oral fibroblasts. In the future, this finding can be translated into clinical procedures, using connective tissue graft to seal an extraction socket in patients receiving ZA.