Systematic review of medication related osteonecrosis of the jaw (MRONJ) in patients undergoing only antiangiogenic drug therapy: surgery or conservative therapy?

Medication-related osteonecrosis of the jaw (MRONJ) systemic review: mevalonate pathway mechanisms explored

Medication-related osteonecrosis of the jaw (MRONJ) is a rare, but devastating condition caused by bisphosphonates, receptor activator of nuclear factor kappa-B ligand inhibitors, anti-angiogenic medications, and disease-modifying antirheumatic drugs. While the clinical spectrum of MRONJ has a wide range, there is a subgroup of patients that do not improve with antibiotics and conservative surgical debridement resulting in pathologic fractures, draining fistulas, and/or osteomyelitis. For the severely affected individuals, the only cure is surgical resection with micro-vascular free flap reconstruction. The etiology of MRONJ is unknown because of the lack of understanding of the biological underpinnings of the disorder connected to the mechanisms of action of the various medications. This limited knowledge has resulted in the classification of patients by clinical presentation rather than underlying pathology. Therefore, the aim of this article is to present a mechanistic framework of MRONJ through the mevalonate pathway in the context of the medications that are known to induce it and explore potential novel therapeutics.

Oral administration of Bifidobacterium breve improves anti-angiogenic drugs-derived oral mucosal wound healing impairment via upregulation of interleukin-10

Recent studies have suggested that long-term application of anti-angiogenic drugs may impair oral mucosal wound healing. This study investigated the effect of sunitinib on oral mucosal healing impairment in mice and the therapeutic potential of Bifidobacterium breve (B. breve). A mouse hard palate mucosal defect model was used to investigate the influence of sunitinib and/or zoledronate on wound healing. The volume and density of the bone under the mucosal defect were assessed by micro-computed tomography (micro-CT). Inflammatory factors were detected by protein microarray analysis and enzyme-linked immunosorbent assay (ELISA). The senescence and biological functions were tested in oral mucosal stem cells (OMSCs) treated with sunitinib. Ligated loop experiments were used to investigate the effect of oral B. breve. Neutralizing antibody for interleukin-10 (IL-10) was used to prove the critical role of IL-10 in the pro-healing process derived from B. breve. Results showed that sunitinib caused oral mucosal wound healing impairment in mice. In vitro, sunitinib induced cellular senescence in OMSCs and affected biological functions such as proliferation, migration, and differentiation. Oral administration of B. breve reduced oral mucosal inflammation and promoted wound healing via intestinal dendritic cells (DCs)-derived IL-10. IL-10 reversed cellular senescence caused by sunitinib in OMSCs, and IL-10 neutralizing antibody blocked the ameliorative effect of B. breve on oral mucosal wound healing under sunitinib treatment conditions. In conclusion, sunitinib induces cellular senescence in OMSCs and causes oral mucosal wound healing impairment and oral administration of B. breve could improve wound healing impairment via intestinal DCs-derived IL-10.

Correlations between Immune Response and Etiopathogenic Factors of Medication-Related Osteonecrosis of the Jaw in Cancer Patients Treated with Zoledronic Acid

Impairment of the immune response in MRONJ (medication-related osteonecrosis of the jaws) is one of the still unclear etiopathogenic mechanisms of this condition encountered in cancer patients treated with bisphosphonates, with negative effects on the patient's quality of life. The aim of the present study was to correlate the immune response with etiopathogenic factors via immunohistochemical evaluation of the maxillary tissues in zoledronic acid osteonecrosis. The retrospective study included a group of 51 patients with various types of cancers, diagnosed with stage 2 or 3 MRONJ at zoledronic acid and treated surgically. Immunohistochemical expressions of αSMA, CD3, CD4, CD8, CD20, CD79α, CD68, CD204, and tryptase were evaluated. Immunohistochemical markers expressions were statistically analyzed according to the duration of the treatment, the trigger factor, the location of the MRONJ, and the healing status. Analysis of the immune response included T lymphocytes, B lymphocytes, plasma cells, macrophages, and mast cells. The duration of treatment significantly influenced the immunohistochemical expression of most markers (p < 0.05). For an increasing trend in treatment duration, a decreasing trend in marker score was observed, suggesting an inverse correlation. The expression of the markers was different depending on the trigger factor, on MRONJ localization (maxilla/mandible), and the healing status, being more intense in patients cured per primam compared to those who had relapses. The patient's immune response was negatively influenced by the duration of the treatment, the trigger factor, the location of the lesion in the mandible, and the recurrence of MRONJ.

Long-term and sequential treatment for osteoporosis

Osteoporosis is a skeletal disorder that causes impairment of bone structure and strength, leading to a progressively increased risk of fragility fractures. The global prevalence of osteoporosis is increasing in the ageing population. Owing to the chronic character of osteoporosis, years or even decades of preventive measures or therapy are required. The long-term use of bone-specific pharmacological treatment options, including antiresorptive and/or osteoanabolic approaches, has raised concerns around adverse effects or potential rebound phenomena after treatment discontinuation. Imaging options, risk scores and the assessment of bone turnover during initiation and monitoring of such therapies could help to inform individualized treatment strategies. Combination therapies are currently used less often than 'sequential' treatments. However, all patients with osteoporosis, including those with secondary and rare causes of osteoporosis, as well as specific patient populations (for example, young adults, men and pregnant women) require new approaches for long-term therapy and disease monitoring. New pathophysiological aspects of bone metabolism might therefore help to inform and revolutionize the diagnosis and treatment of osteoporosis.

Anti-angiogenic drug aggravates the degree of anti-resorptive drug-based medication-related osteonecrosis of the jaw by impairing the proliferation and migration function of gingival fibroblasts

BACKGROUND

Long-term use of anti-resorptive or anti-angiogenic drugs in cancer patients with odontogenic infections may lead to medication-related osteonecrosis of the jaw (MRONJ). This study investigated whether anti-angiogenic agents aggravate MRONJ occurrence in anti-resorptive-treated patients.

METHODS

The clinical stage and jawbone exposure of MRONJ patients caused by different drug regimens were analyzed to ascertain the aggravation effect of anti-angiogenic drugs on anti-resorptive drug-based MRONJ. Next, a periodontitis mice model was established, and tooth extraction was performed after administering anti-resorptive and/or anti-angiogenic drugs; the imaging and histological change of the extraction socket were observed. Moreover, the cell function of gingival fibroblasts was analyzed after the treatment with anti-resorptive and/or anti-angiogenic drugs in order to evaluate their effect on the gingival tissue healing of the extraction socket.

RESULTS

Patients treated with anti-angiogenic and anti-resorptive drugs had an advanced clinical stage and a bigger proportion of necrotic jawbone exposure compared to patients treated with anti-resorptive drugs alone. In vivo study further indicated a greater loss of mucosa tissue coverage above the tooth extraction in mice treated with sunitinib (Suti) + zoledronate (Zole) group (7/10) vs. Zole group (3/10) and Suti group (1/10). Micro-computed tomography (CT) and histological data showed that the new bone formation in the extraction socket was lower in Suti + Zole and Zole groups vs. Suti and control groups. In vitro data showed that the anti-angiogenic drugs had a stronger inhibitory ability on the proliferation and migration function of gingival fibroblasts than anti-resorptive drugs, and the inhibitory effect was obviously enhanced after combining zoledronate and sunitinib.

CONCLUSION

Our findings provided support for a synergistic contribution of anti-angiogenic drugs to anti-resorptive drugs-based MRONJ. Importantly, the present study revealed that anti-angiogenic drugs alone do not induce severe MRONJ but aggravate the degree of MRONJ via the enhanced inhibitory function of gingival fibroblasts based on anti-resorptive drugs.

Novel VEGFR-2 Kinase Inhibitors as Anticancer Agents: A Review Focusing on SAR and Molecular Docking Studies (2016-2021)

Cancer growth, annexation, and metastatic spread are all aided by the formation of new blood vessels (angiogenesis). The commencement of the VEGF pathway leads to signal transduction that enhances endothelial cell survival, relocation, and divergence from pre-existing vasculature. The ability of solid malignancies to bloom and spread depends critically on their ability to establish their independent blood circulation (tumor angiogenesis). VEGFR is a major receptor tyrosine kinase that regulates angiogenesis, cell growth, and metastasis, diminishing apoptosis, cytoskeletal function, and other biological processes VEGFR has proven to be a remarkable focus for a variety of anticancer medicines in clinical studies. This Review explores the development of anti-VEGF-based antiangiogenic therapies having different scaffolds. This review had focused on SAR and docking studies of previously reported molecules.

Oral Side Effects in Patients with Metastatic Renal Cell Carcinoma Receiving the Antiangiogenic Agent Pazopanib-Report of Three Cases

Pazopanib is a potent multi-kinase inhibitor that hinders angiogenesis and blocks tumor growth. It has been approved for the treatment of metastatic renal cell carcinoma (mRCC) and advanced soft tissue sarcoma. There is emerging evidence that bleeding is a common adverse effect of pazopanib and other targeted therapies in patients with mRCC. In addition, jaw osteonecrosis related to pazopanib was recently described in the literature. We report three cases of patients with mRCC who developed adverse oral events related to pazopanib. The first patient, treated with pazopanib as monotherapy, presented with gingival bleeding and oral burning sensation. The other two patients receiving pazopanib as monotherapy and pazopanib followed by sunitinib, respectively, presented complaining about mandibular pain; a diagnosis of medication-related osteonecrosis of the jaw (MRONJ) was rendered in both cases. Gingival bleeding and MRONJ may develop as oral side effects of pazopanib use. The cases presented here aim to alert and inform health care professionals about the risk of adverse oral events in patients with mRCC receiving the antiangiogenic agent pazopanib.

Bone Concentration of Ampicillin/Sulbactam: A Pilot Study in Patients with Osteonecrosis of the Jaw

Osteonecrosis of the jaw (ONJ) occurs typically after irradiation of the head and neck area or after the intake of antiresorptive agents. Both interventions can lead to compromised bone perfusion and can ultimately result in infection and necrosis. Treatment usually consists of surgical necrosectomy and prolonged antibiotic therapy, usually through beta-lactams such as ampicillin/sulbactam. The poor blood supply in particular raises the question as to whether this form of antibiosis can achieve sufficient concentrations in the bone. Therefore, we investigated the antibiotic concentration in plasma and bone samples in a prospective study. Bone samples were collected from the necrosis core and in the vital surrounding bone. The measured concentrations in plasma for ampicillin and sulbactam were 126.3 ± 77.6 and 60.2 ± 35.0 µg/mL, respectively. In vital bone and necrotic bone samples, the ampicillin/sulbactam concentrations were 6.3 ± 7.8/1.8 ± 2.0 µg/g and 4.9 ± 7.0/1.7 ± 1.7 µg/g, respectively. These concentrations are substantially lower than described in the literature. However, the concentration seems sufficient to kill most bacteria, such as Streptococci and Staphylococci, which are mostly present in the biofilm of ONJ. We, therefore, conclude that intravenous administration of ampicillin/sulbactam remains a valuable treatment in the therapy of ONJ. Nevertheless, increasing resistance of Escherichia coli towards beta-lactam antibiotics have been reported and should be considered.

Contribution of Antiangiogenic Agents to the Risk of Medication-related Osteonecrosis of the Jaw in Combination with Antiresorptive Agents: Preliminary Results in a Comparative Prospective Report of 59 Oncologic Cases

AIM

The aim of this preliminary study was to evaluate in an oncological population the association risk of antiangiogenic (AA) agents to antiresorptive (AR) agents on the incidence and the severity of medication-related osteonecrosis of the jaw (MRONJ).

MATERIALS AND METHODS

In this prospective study, we reviewed the medical records and clinical variables of 59 consecutive oncologic patients who developed MRONJ. For all patients, we retrieved the following variables: age, gender, alcohol and tobacco use, type of cancer, use of corticosteroids for >3 months, history of diabetes, MRONJ staging, combination of AR and AA agents, dental history (surgery, prosthesis) or spontaneous, site of MRONJ, delay between AR and AA first intake, and MRONJ development. Patients were divided into two groups according to drugs therapy they underwent: group 1 (G1) including patients treated with AR agents alone and group 2 (G2) including patients receiving antiresorptive-antiangiogenic drugs (AR+AA). The degree and the therapeutical success were defined as primary outcomes and the number, the localization, and the delay in onset of the lesions as secondary outcomes. In order to identify predictive factors of osteonecrosis-free interval time, univariate and multivariate Cox regression was performed. Statistical tests were carried out using the IBM^® SPSS^® Statistics software. All reported P-values are two-tailed and were considered to be significant when less than 0.05.

RESULTS

Among the 47 patients who received AR agent alone (group 1), the mean treatment duration before diagnosis of MRONJ was 39.2 months. In the second group (n = 12), patients developed MRONJ with a comparable mean time of 55 months (P = 0.16). According to the staging of MRONJ at the time of diagnosis, no significant difference (P = 0.736) was observed between the two groups. Moreover, the treatment applied was not statistically different in both the groups and was successful in 36.17% of the patients in group 1 and 58.33% of the patients in group 2. No statistically difference was reported in both the groups (P = 0.16). After statistical analysis, no significant difference in terms of MRONJ localization (P = 0.13) was observed. Finally, the incidence of spontaneous MRONJ was comparable in both the groups. Statistical analysis revealed that total time of treatment was the only factor associated with poor osteonecrosis-free interval time (hazard ratio 0.99; P = 0.001). Interestingly, the combination of an AA and AR agent was not a significant predictor factor of the interval time before the diagnosis of osteonecrosis. Additionally, corticosteroid use, diabetes mellitus, and dental consultation before treatment were not statistically related to poorer osteonecrosis-free interval time rates.

CONCLUSION

In our preliminary study, neither the mean treatment time duration before the diagnosis of MRONJ nor the dose delivered was different in both the groups (AR vs. AR+AA). Moreover, no significant difference was observed between both the groups regarding the localization and the staging of MRONJ at the time of diagnosis. Interestingly, our results demonstrated that the risk of spontaneous MRONJ is statistically comparable in the AR and AR-AA groups. Additionally, the addition of an AA agent did not influence the treatment applied in the two groups of patients.