Bone turnover markers can predict healing time in medication-related osteonecrosis of the jaw

Role of sclerostin deletion in bisphosphonate-induced osteonecrosis of the jaw

PURPOSE

Bone resorption inhibitors, such as bisphosphonates (BP) and denosumab, are frequently used for the management of osteoporosis. Although both drugs reduce the risk of osteoporotic fractures, they are associated with a serious side effect known as medication-related osteonecrosis of the jaw (MRONJ). Sclerostin antibodies (romosozumab) increase bone formation and decrease the risk of osteoporotic fractures: however, their anti-resorptive effect increases ONJ. Thus, this study aimed to elucidate the role of sclerostin deletion in the development of MRONJ.

METHODS

Sclerostin knockout (SostΔ26/Δ26) mice were used to confirm the development of ONJ by performing tooth extractions. To confirm the role of sclerostin deficiency in a more ONJ-prone situation, we used the BP-induced ONJ model in combination with severe periodontitis to evaluate the development of ONJ and bone formation in wild-type (WT) and SostΔ26/Δ26 mice. Wound healing assay using gingival fibroblasts with or without sclerostin stimulation and tooth extraction socket healing were evaluated in the WT and SostΔ26/Δ26 mice.

RESULTS

ONJ was not detected in the extraction socket of SostΔ26/Δ26 mice. Moreover, the incidence of ONJ was significantly lower in the SostΔ26/Δ26 mice treated with BP compared to that of the WT mice. Osteogenic proteins, osteocalcin, and runt-related transcription factor 2, were expressed in the bone surface in SostΔ26/Δ26 mice. Recombinant sclerostin inhibited gingival fibroblast migration. The wound healing rate of the extraction socket was faster in SostΔ26/Δ26 mice than in WT mice.

CONCLUSION

Sclerostin deficiency did not cause ONJ and reduced the risk of developing BP-induced ONJ. Enhanced bone formation and wound healing were observed in the tooth extraction socket. The use of romosozumab (anti-sclerostin antibody) has proven to be safe for surgical procedures of the jaw.

Clinical risk factors for severity and prognosis of antiresorptive agent-related osteonecrosis of the jaw: a retrospective observational study

INTRODUCTION

The incidence of antiresorptive agent-related osteonecrosis of the jaw (ARONJ) is rare, and its management has not yet been established. This study aimed to investigate the predictors for advanced stage and healing of ARONJ to establish an appropriate treatment strategy.

MATERIALS AND METHODS

We retrospectively analyzed patients diagnosed with ARONJ at Kobe City Medical Center General Hospital between April 2014 and March 2020. Outcomes were defined as stage ≥ 2 ARONJ (primary) and healing of ARONJ (secondary). Multivariate logistic regression analysis was used to detect factors associated with the outcomes, and odds ratios (OR) and 95% confidence intervals (CI) were calculated.

RESULTS

This study included 143 patients (stage ≥ 2 ARONJ, 51%; healing of ARONJ, 60%). Multivariate logistic regression analysis revealed that advanced age (per year) (OR 1.037; 95% CI 1.003-1.072; p = 0.028) and serum albumin (per g/dL) (OR 0.430; 95% CI 0.213-0.869; p = 0.018) were significantly associated with stage ≥ 2 ARONJ. Furthermore, multivariate logistic regression analysis revealed that cancer (yes) (OR 0.099; 95% CI 0.029-0.339; p < 0.001), conservative surgical treatment (yes) (OR 15.42; 95% CI 5.657-42.0; p < 0.001), C-reactive protein (per mg/dL) (OR 0.599; 95% CI 0.415-0.864; p < 0.001), and vitamin D analog (yes) (OR 0.167; 95% CI 0.034-0.827; p = 0.028) were factors associated with healing.

CONCLUSION

Our findings suggest that age and hypoalbuminemia are associated with the severity of ARONJ, and cancer, high inflammation, and vitamin D analog may impair healing. In contrast, conservative surgical treatment can overcome the poor treatment outcomes associated with ARONJ.