Teriparatide's role in the management of bisphosphonate-associated osteonecrosis of the jaw

Osteochemonecrosis: an overview

Osteonecrosis of the jaw to a certain extent has been with us for many years. But recently the advent of various medications such as bisphosphonates, VEGF inhibitors, tyrosine kinase inhibitors and humanized antibodies to osteoclastic action have resulted in thousands of cases. While the bisphosphonates continue to be the most common medication associated with osteochemonecrosis antibodies such as denosumab which irreversibly act on osteoclastic action are also being reported. This narrative review will serve as an update with a focus on some of the histopathologic features discussed and reviewed. Perhaps even more uncommonly seen in past reports a discussion of features possibly observed while grossing specimens will be discussed. At the end of this report is hoped that the pathologist will have a better understanding of the historical features, clinical settings, gross examination features as well as histopathologic features associated with osteochemonecrosis.

Teriparatide and the treatment of bisphosphonate-related osteonecrosis of the jaw: a rat model

OBJECTIVES

The objectives of this study were to establish a bisphosphonate-related osteonecrosis of the jaw (BRONJ) rat model and to analyse the effects of teriparatide (TP) on this model.

METHODS

Sprague-Dawley rats were divided into three groups: I-zoledronic acid (ZA, n = 10); II-ZA and teriparatide (ZA + TP, n = 10); III-control (n = 10). Osteonecrosis was induced by administering zoledronic acid to groups ZA and ZA + TP. A week after the injections, rats underwent extraction of the first left mandibular molar. Following a four week period, TP was administered to the ZA + TP group for 28 days. Upon killing, extraction sockets were examined clinically, radiologically and histopathologically.

RESULTS

Clinical examination revealed necrotic bone exposure in none of the animals. MicroCT (µCT) examination showed that bone mineral density of the newly formed bone in the extraction socket was lower in the ZA group than in the ZA + TP group (p < 0.05). Histopathological examination revealed that only the ZA and ZA + TP groups developed osteonecrosis, and the osteonecrotic bone area in the ZA group was larger than that in the ZA + TP group (p < 0.05). Tartrate-resistant acid phosphatase (TRAcP) enzyme histochemistry revealed that the number of detached and large osteoclasts were higher in the ZA group than in other groups, whereas the number of apoptotic osteoclasts in both ZA and ZA + TP groups were higher than in the control group (p < 0.05).

CONCLUSIONS

Our data indicate that bisphosphonate-related osteonecrosis of the jaw model used in the present study is an attractive model to investigate treatment modalities and that TP might be an effective treatment in BRONJ.

Adjunct teriparatide therapy with monitoring of bone turnover markers and bone scintigraphy for bisphosphonate-related osteonecrosis of the jaw

The management of bisphosphonate-related osteonecrosis of the jaw (BRONJ) is still difficult in many cases that do not respond to conservative treatments. We report a case of BRONJ treated by adjunctive teriparatide therapy for 6 months with monitoring of bone turnover markers (at baseline, at 1, 3, and 6 months of treatment, and after 9 months off therapy) and bone scintigraphy (at baseline, 3 and 6 months, and after 9 months off therapy). The patient was a 78-year-old woman with osteoporosis and BRONJ. She had not responded to previous conventional treatment. Teriparatide was added for resolution of BRONJ. The pain disappeared after 1 month, and remarkable bone regeneration was obtained after 6 months, with significantly increasing bone formation and resorption markers. Bone scintigraphy showed regression of the uptake area. This case suggests the usefulness of monitoring bone turnover markers and using bone scintigraphy to increase the effectiveness of teriparatide therapy.