Bisphosphonates inhibit surface-mediated osteogenesis

Medication-related osteonecrosis of the jaw (MRONJ): a review of pathogenesis hypothesis and therapy strategies

Medication-related osteonecrosis of the jaw (MRONJ), a severe side effect caused by antiresorptive antiangiogenic medication, particularly bisphosphonates (BPs), has become a challenging disease with serious and profound effects on the physical and mental health of patients. Although it occurs with high frequency and is harmful, the exact mechanism of MRONJ remains unknown, and systematic and targeted approaches are still lacking. Maxillofacial surgeons focus on the etiology of osteonecrosis in the mandible and maxilla as well as the appropriate oral interventions for high-risk patients. Adequate nursing care and pharmacotherapy management are also crucial. This review provides a current overview of the clinicopathologic feature and research of MRONJ caused by BPs, with an emphasis on the potential mechanisms and current therapy and prevention strategies of the disease. We are of the opinion that an in-depth comprehension of the mechanisms underlying MRONJ will facilitate the development of more precise and efficacious therapeutic approaches, resulting in enhanced clinical outcomes for patients.

Could MRONJ Be Related to Osimertinib Monotherapy in Lung Cancer Patients after Denosumab Suspension?

BACKGROUND

Medication-related osteonecrosis of the jaws is the most frequent complication in patients treated or in therapy with antiresorptive/antiangiogenetic drugs. The list of medications possibly related to MRONJ onset is constantly growing; we aimed to report on a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (Osimertinib) as possibly responsible for bilateral maxillary necrosis onset in the herein-described case.

METHODS

In June 2023, an oncologic patient with two different maxillary bone exposures was referred to our attention. His medical history revealed a two-year Denosumab regimen along with Osimertinib, the latter not suspended before teeth extractions. The clinicians performed a sequestrum removal and bone debridement after three cycles of antibiotic therapy.

RESULTS

Histologic examinations confirmed the clinical diagnosis of MRONJ excluding a metastatic occurrence, while complete mucosal healing was achieved after 15 days.

CONCLUSIONS

The patient suspended Denosumab for more than six months before teeth extraction for MRONJ prevention; hence, failure to discontinue Osimertinib led us to consider it a possible etiological factor. From a literature analysis, only one case has already been published reporting a possible Osimertinib-related occurrence of MRONJ in lung cancer patients. Our case is a further report that could be intended as an alert both for oncologists and dentists to share decisions about the oral management of such patients together, also informing them about this possible risk. Also, this report could trigger in the scientific community the necessity to evaluate further guidelines for similar doubtful cases in which the drug interaction, the mono-suspension, and the possible removable prosthesis-related additional trauma should be considered causes or con-causes.

Functional β-TCP/MnO2 /PCL artificial periosteum promoting osteogenic differentiation of BMSCs by reducing locally reactive oxygen species level

Segmental bone defects caused by trauma, tumor resection or congenital malformations are often reconstructed with autologous, allogeneic bone grafts or artificial bone materials, of which, about 5% ~ 10% will have delayed healing or even nonunion of fractures. The loss of periosteum and excessive accumulation of ROS in fracture site leads to the aging of osteoblasts and the decline of their proliferation and differentiation, thus affecting the fracture healing process. In this study, we prepared a functional modified artificial periosteum β-TCP/MnO2 /PCL(β-TMP) by electrospinning with a function of catalyzing decomposition of H2 O2 . We examined the surface morphology of β-TMP, the concentration of Ca, P and Mn of β-TMP, as well as the diameter distribution range of nanofibers on β-TMP. Through X-ray diffraction patterns and Fourier transform infrared spectra, β-TMP was characterized and its hydrophilicity was tested. The release of Mn2+ and Ca2+ of 0.1 and 0.05% β-TMP in different pH values (7.4 and 5.5) determined by ICP. We also identified that β-TMP could reduce the level of ROS in cells by lowering the level of H2 O2 . 0%, 0.05% and 0.1% β-TMP displayed good cell compatibility, cell adhesion and cellular morphology in the condition with or without H2 O2 . 0.5% β-TMP showed compromised cell compatibility in normal condition, however, the compromised phenotypes could be partially rescued in the present of H2 O2 . Compared with 0%, 0.05% and 0.1% β-TMP displayed higher osteoblastic differentiation with or without H2 O2 in BMSCs as well as in MG-63. In sum, β-TMP helped osteogenesis and promoted repair of bone defects.

Enhancing the Oral Rehabilitation and Quality of Life of Bisphosphonate-Treated Patients: The Role of Dental Implants

The purpose of this review is to examine the literature on the topic of bisphosphonate-related osteonecrosis of the jaw (BRONJ) and dental implant failure in patients undergoing bisphosphonate (BP) therapy who also received dental implants before, during, or after BP treatment, as compared to healthy patients. This research followed the guidelines in the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. The "PICO" or population, intervention, comparison, and outcome clinical question was as follows: does the insertion of dental implants in patients receiving bisphosphonate therapy increase the failure and loss of implants or the incidence of bisphosphonate-related osteonecrosis of the jaw compared to healthy patients? The articles published in PubMed/Medical Literature Analysis and Retrieval System Online (MEDLINE) up to July 1, 2023, were retrieved using a mix of Medical Subject Heading (MeSH) words and their entry terms. The absence of randomized clinical trials examining this issue underscores the need for additional studies with extended follow-ups to answer outstanding questions. Because of the potential for BRONJ and implant failure, patients receiving bisphosphonate medication should exercise caution when planning dental implant surgery. In addition, when such procedures are carried out, the patient's entire systemic condition must be considered.

Association of bisphosphonates with diabetes risk and glycemic control: a meta-analysis

Previous evidence suggests that bisphosphonates may improve glycemic control. The present meta-analysis, comprising seven studies with 1,233,844 participants, demonstrated that bisphosphonate use was significantly associated with a lower risk of diabetes. However, in the randomized controlled trial subgroup, a non-significant association was found. Further studies are needed to determine causality.

PURPOSE

This study aimed to evaluate the impact of bisphosphonates on glycemic control and the risk of incident diabetes.

METHODS

MEDLINE, Embase, and Cochrane Library were searched from inception to February 15, 2022. Experimental or observational studies that compared fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) levels and the diabetes risk with and without bisphosphonates were included. Studies without relevant outcomes, only providing crude estimates, or the absence of a control group were excluded. Two reviewers independently screened the articles, extracted data, and appraised studies. The pooled relative risk (RR) and weighted mean difference (WMD) were calculated using random effects models.

RESULTS

Seven studies (n = 1,233,844) on diabetes risk were included, including two post hoc analyses of randomized controlled trials (RCTs) and five observational studies. Compared with controls, bisphosphonates (BPs) were associated with a significant decrease in the risk of diabetes (RR = 0.77; 95% CI, 0.65 to 0.90; P = 0.002). However, in the subgroup of post hoc analyses of RCTs, the association was non-significant (RR = 0.93; 95% CI, 0.74 to 1.18; P = 0.576). Moreover, three studies (n = 4906) on FBG and one (n = 60) on HbA1c were included. We observed non-significant association between BPs and changes in FBG (WMD =  - 0.61 mg/dL; 95% CI, - 2.72 to 1.49; P = 0.567) and HbA1c (WMD =  - 0.11%; 95% CI, - 0.23 to 0.01; P = 0.083).

CONCLUSION

Patients taking BPs may have a lower risk of incident diabetes than those without BPs. However, due to the high between-study heterogeneity and inconsistent findings between post hoc analyses of RCTs and observational studies, further rigorous RCTs are required to determine whether the findings are causal.

Berbamine inhibits RANKL- and M-CSF-mediated osteoclastogenesis and alleviates ovariectomy-induced bone loss

Osteoporosis is a common public health problem characterized by decreased bone mass, increased bone brittleness and damage to the bone microstructure. Excessive bone resorption by osteoclasts is the main target of the currently used drugs or treatment for osteoporosis. Effective antiresorptive drugs without side effects following long-term administration have become a major focus of anti-osteoporotic drugs. In the present study, we investigated the effect of berbamine, a small molecule natural product from Berberis amurensis Rupr, a traditional Chinese medicine, on RANKL-induced osteoclast differentiation in vitro and ovariectomy-induced bone loss in vivo. The results demonstrated that berbamine at a safe and effective dose inhibited osteoclastogenesis and bone resorption function in vitro by suppressing the nuclear factor-κB signaling pathway. In addition, berbamine protected against osteoporosis by inhibiting osteoclastogenesis and bone resorption function without affecting osteogenesis in the ovariectomy mouse model. These findings revealed that berbamine has a protective role against osteoporosis and may represent a novel promising treatment strategy for osteoporosis.

Osseointegration and Remodeling of Mineralized Bone Graft Are Negatively Impacted by Prior Treatment with Bisphosphonates

BACKGROUND

Bisphosphonates limit resorption by inhibiting osteoclast formation and activation. They are removed during preparation of demineralized bone matrix (DBM) particles, but it is not known if osteogenesis and incorporation of mineralized bone allografts from patients treated with oral bisphosphonates are affected in vivo.

METHODS

Human block allografts from 3 bisphosphonate-treated donors and 3 age and sex-matched control donors who had not received bisphosphonates were obtained (Musculoskeletal Transplant Foundation); one-half from each donor was demineralized. In the first study, 3 × 2-mm mineralized and demineralized cylindrical grafts were implanted bilaterally in the femoral metaphysis of 56 rats. In the second study, samples from each group were pooled, prepared as particles, and implanted bilaterally in the femoral marrow canal of 24 rats. Osseointegration, defined as native bone in contact with allograft, was assessed at 10 weeks by micro-computed tomography (CT) and histomorphometry.

RESULTS

Micro-CT showed greater bone volume in sites treated with demineralized samples compared with the control mineralized and bisphosphonate-exposed mineralized samples. More new bone was generated along the cortical-endosteal interface compared with mineralized samples. Histology showed significantly less new bone in contact with the mineralized bisphosphonate-exposed allograft (10.4%) compared with mineralized samples that did not receive bisphosphonates (22.8%) and demineralized samples (31.7% and 42.8%). A gap was observed between native bone and allograft in the bisphosphonate-exposed mineralized samples (0.50 mm 2 ). The gap area was significantly greater compared with mineralized samples that did not receive bisphosphonates (0.16 mm 2 ) and demineralized samples (0.10 and 0.03 mm 2 ).

CONCLUSIONS

Mineralized allografts were osseointegrated, but not remodeled or replaced by living bone, preventing full regeneration of the bone defect. Prior treatment of the donor with bisphosphonates affected osteogenesis, preventing osteointegration and remodeling of the allograft into the regenerating bone.

CLINICAL RELEVANCE

Clinical use of mineralized allografts from patients who had received bisphosphonate therapy needs to be evaluated; in this animal model, such grafts were not integrated into the host bone or remodeled, and full regeneration of the bone defects was prevented.

Inhibitory Effect of Biotransformed-Fucoidan on the Differentiation of Osteoclasts Induced by Receptor for Activation of Nuclear Factor-κB Ligand

Bone homeostasis is regulated by constant remodeling through osteogenesis by osteoblasts and osteolysis by osteoclasts and osteoporosis can be provoked when this balance is broken. Present pharmaceutical treatments for osteoporosis have harmful side effects and thus, our goal was to develop therapeutics from intrisincally safe natural products. Fucoidan is a polysaccharide extracted from many species of brown seaweed, with valuable pharmaceutical activities. To intensify the effect of fucoidan on bone homeostasis, we hydrolyzed fucoidan using AMG, Pectinex and Viscozyme. Of these, fucoidan biotransformed by Pectinex (Fu/Pec) powerfully inhibited the induction of tartrate-resistant acid phosphatase (TRAP) activity in osteoclasts differentiated from bone marrow macrophages (BMMs) by the receptor for activation of nuclear factor-κB ligand (RANKL). To investigate potential of lower molecular weight fucoidan it was separated into >300 kDa, 50-300 kDa, and <50 kDa Fu/Pec fractions by ultrafiltration system. The effects of these fractions on TRAP and alkaline phosphatase (ALP) activities were then examined in differentiated osteoclasts and MC3T3-E1 osteoblasts, respectively. Interestingly, 50-300 kDa Fu/Pec suppressed RANKL-induced osteoclasts differentiation from BMMs but did not synergistically enhance osteoblasts differentiation induced by osteogenic agents. In addition, this fraction inhibited the expressions of NFATc1, TRAP, OSCAR, and RANK, which are all key transcriptional factors involved in osteoclast differentiation, and those of Src, c-Fos and Mitf, as determined by RT-PCR. In conclusion, enzymatically low-molecularized 50-300 kDa Fu/Pec suppressed TRAP by downregulating RANKL-related signaling, contributing to the inhibition of osteoclasts differentiation, and represented a potential means of inducing bone remodeling in the background of osteoporosis.

Testosterone Enanthate: An In Vitro Study of the Effects Triggered in MG-63 Cells

The aim of this study was to investigate the effects of the androgenic hormone testosterone enanthate (TE) on human MG-63 cells. MG-63 were cultured for 24 h in the presence of TE at increasing concentrations to assess its lethal dose. Therefore, the suitable concentration for a prolonged use of TE in vitro was assessed by viability assay over 9 days. Finally, MG-63 were exposed to TE for 14 days and assayed for differentiation by qPCR and Alizarin Red S staining. TE in the amount of 100 µM resulted as the maximum dose tolerated by MG-63 cells after 24 h. However, a prolonged exposure in culture TE in the amount of 100 µM showed a cytostatic effect on cell proliferation. On the contrary, TE 10 µM was tolerated by the cells and did not boost cell proliferation, but did enhance new bone formation, as revealed by COL1A1, ALPL, BGLAP, and IBSP gene expression after 3, 7, and 14 days, and calcium deposition by Alizarin Red S staining after 14 days. Based on the current study, 10 µM is the critical dose of TE that should be used in vitro to support bone differentiation of MG-63 cells.

Ibandronate Suppresses Changes in Apatite Orientation and Young's Modulus Caused by Estrogen Deficiency in Rat Vertebrae

Bone material quality is important for evaluating the mechanical integrity of diseased and/or medically treated bones. However, compared to the knowledge accumulated regarding changes in bone mass, our understanding of the quality of bone material is lacking. In this study, we clarified the changes in bone material quality mainly characterized by the preferential orientation of the apatite c-axis associated with estrogen deficiency-induced osteoporosis, and their prevention using ibandronate (IBN), a nitrogen-containing bisphosphonate. IBN effectively prevented bone loss and degradation of whole bone strength in a dose-dependent manner. The estrogen-deficient condition abnormally increased the degree of apatite orientation along the craniocaudal axis in which principal stress is applied; IBN at higher doses played a role in maintaining the normal orientation of apatite but not at lower doses. The bone size-independent Young's modulus along the craniocaudal axis of the anterior cortical shell of the vertebra showed a significant and positive correlation with apatite orientation; therefore, the craniocaudal Young's modulus abnormally increased under estrogen-deficient conditions, despite a significant decrease in volumetric bone mineral density. However, the abnormal increase in craniocaudal Young's modulus did not compensate for the degradation of whole bone mechanical properties due to the bone loss. In conclusion, it was clarified that changes in the material quality, which are hidden in bone mass evaluation, occur with estrogen deficiency-induced osteoporosis and IBN treatment. Here, IBN was shown to be a beneficial drug that suppresses abnormal changes in bone mechanical integrity caused by estrogen deficiency at both the whole bone and material levels.

Hydrophilic implants generated using a low-cost dielectric barrier discharge plasma device at the time of placement exhibit increased osseointegration in an animal pre-clinical study: An effect that is sex-dependent

OBJECTIVES

Increased wettability of titanium and titanium alloy surfaces due to processing and storage methods increases osteoprogenitor cell differentiation and osseointegration compared to microroughness alone. Implants that are exposed to air have a hydrophobic surface due to adsorption of atmospheric hydrocarbons, which can limit overall implant success. Dielectric barrier discharge plasma (DBD) is one method to increase surface hydrophilicity. Although current DBD methods yield a hydrophilic surface, adsorbed hydrocarbons rapidly restore hydrophobicity. We demonstrated that application of DBD to implants previously packaged in a vacuum, generates a hydrophilic surface that supports osteoblastic differentiation in vitro and this can be done immediately prior to use. In the present study, we tested the hypothesis that DBD treatment to alter surface wettability at the time of implant placement will improve osseointegration in vivo.

MATERIALS AND METHODS

Twenty male and sixteen female rabbits were used in a preclinical trans-axial femur model of osseointegration. Control and DBD treatment implants were inserted randomized per hind limb in each rabbit (1 implant/hind-limb). At 6 weeks post-surgery, bone-to-implant contact, adjacent bone volume, and torque to failure were assessed by micro-CT, calcified histology, and mechanical testing.

RESULTS

DBD plasma treatment of vacuum-sealed implants increased surface wettability and did not change surface chemistry or roughness. Peak torque and torsional energy, and bone-to-implant contact increased with DBD treatment in males. In contrast, female rabbits showed increased osseointegration equal to DBD treated male implants regardless of DBD plasma treatment.

CONCLUSION

DBD treatment is an effective method to enhance osseointegration by increasing surface wettability; however, this response is sex dependent. In healthy female patients, DBD treatment may not be necessary but in older patients or patients with compromised bone, this treatment could be an effective measure to ensure implant success.

Differential Effects of Neurectomy and Botox-induced Muscle Paralysis on Bone Phenotype and Titanium Implant Osseointegration

Metabolic bone is highly innervated by both sensory and sympathetic nerves. In addition to skeletal development, neural regulation participates in local bone remodeling, which is important for successful osseointegration of titanium implants. Neurectomy is a model used to investigate the lack of neural function on bone homeostasis, but the relative impacts of direct denervation to bone or denervation-induced muscle paralysis are less well defined. To investigate this difference, we used two nerve intervention models, sciatic and femoral neurectomy (SFN) v. botox-induced muscle paralysis (BTX) and assessed the resulting femoral bone phenotype and Ti implant osseointegration. Male Sprague Dawley rats (19) were randomly divided into three groups: implant control (n = 5), SFN (n = 7), and BTX (n = 7). Ti implants (microrough/hydrophilic [modSLA], Institut Straumann AG) were placed in the distal metaphysis of each femur on day 24 post-SFN or BTX. Bone and muscle were examined on day 28 after implant insertion. Both nerve intervention models impaired osseointegration. MicroCT and histology indicated that both models had reduced trabecular bone formation. Only BTX reduced cortical bone formation and increased cortical bone porosity. BTX resulted in more bone loss characterized by the least trabecular and cortical bone, as well as osseointegration. Osteoblasts isolated from the tibia exhibited a model-specific phenotype when they were grown on Ti substrates in vitro. Neurectomy caused more severe muscle atrophy than botox injection. These results indicate that neural regulation directly modulates bone formation and osseointegration. Muscle paralysis modulated the effects of loss of neural inputs into bone, supporting the hypothesis that mechanical loading of bone is a factor in achieving successful osseointegration. The different effects of botox and neurectomy on bone phenotype indicated that the sensory and sympathetic nerves had a role in the osseointegration process.

Effects of EGF-coated titanium surfaces on adhesion and metabolism of bisphosphonate-treated human keratinocytes and gingival fibroblasts

OBJECTIVE

To assess the effects of epidermal growth factor (EGF)-coated titanium (Ti) discs on the adhesion and metabolism of keratinocytes and gingival fibroblasts exposed to nitrogen-containing bisphosphonates.

MATERIALS AND METHODS

Keratinocytes and fibroblasts were seeded (1 × 10⁵ cells/disc) on Ti discs coated with EGF (100 nM). After 24 h, cells were exposed or not to sodium alendronate (SA) or zoledronic acid (ZA) at different concentrations (0 = control, 0.5, 1, or 5 μM) for 48 h. Cell adhesion to the substrates was evaluated by fluorescence microscopy. Cell viability (alamarBlue, n = 6) and synthesis of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2), and keratinocytes growth factor (KGF) (ELISA, n = 6) were assessed. Data were statistically analyzed by one-way ANOVA and Tukey tests (α = 0.05).

RESULTS

Higher cell adhesion rate was observed when keratinocytes and fibroblasts were seeded onto EGF-coated discs in comparison to uncoated discs. ZA treatment hindered the adhesion of both cell lines on the Ti discs as well as reduced the viability and synthesis of VEGF, KGF and MMP-2 by cells (p < 0.05). SA treatment did not affect cell viability, but interfered negatively on the adhesion and synthesis of EGF and KGF by the cells (p < 0.05). EGF-coated surface increased cell viability and synthesis of growth factors as well as downregulated the synthesis of MMP-2 in comparison to control (p < 0.05).

CONCLUSION

EGF applied on Ti surface improves the biological responses of oral mucosa cells exposed to SA and ZA.

CLINICAL RELEVANCE

EGF-coating on titanium may be a suitable strategy to improve oral mucosa cellular events related to biological sealing, especially for patients under bisphosphonate therapy.

Bone metabolism regulation: Implications for the treatment of bone diseases

Bone cells in the human body are continuously engaged in cellular metabolism, including the interaction between bone cells, the interaction between the erythropoietic cells of the bone marrow and stromal cells, for the remodeling and reconstruction of bone. Osteoclasts and osteoblasts play an important role in bone metabolism. Diseases occur when bone metabolism is abnormal, but little is known about the signaling pathways that affect bone metabolism. The study of these signaling pathways will help us to use the relevant techniques to intervene, so as to improve the condition. The study of these signaling pathways will help us to use the relevant techniques to intervene, so as to improve the condition. I believe they will shine in the diagnosis and treatment of future clinical bone diseases.