Bisphosphonate-related osteonecrosis of jaw (BRONJ): an anti-angiogenic side-effect?

Polymeric Nanoformulation of Zoledronic Acid Rescues Osteoblasts from the Harmful Effect of its Native Form: An In Vitro Investigation of Cytotoxic Potential on Osteoblasts and Osteosarcoma Cells

Osteosarcoma (OS) is a malignant tumor, fatal for pediatric patients who do not respond to chemotherapy, alternative therapies and drugs can provide better outcomes. Zoledronic acid (Zol) belonging to the class of bisphosphonates (BPs) has a direct antitumor ability to prevent Ras GTPases modification and stimulate apoptosis. Despite advances in maintaining balance in skeletal events and direct anticancer properties, Zol causes cytotoxicity to normal healthy pre-osteoblast cells, hampering mineralization and differentiation. The study reports the preparation and evaluation of a nanoformulation that can diminish the existing drawbacks of native Zol. The cytotoxic effect is evaluated on bone cancer cells and healthy bone cells with three different cell lines namely, K7M2 (mouse OS cell line), SaOS2 (human OS cell line), and MC3T3E1 (healthy cell counterpart). It is observed that Zol nanoformulation is uptaken more (95%) in K7M2 whereas in MC3T3E1, the percent population internalizing nanoparticles (NPs) is 45%. Zol has a sustained release of 15% after 96 h from the NP which leads to a rescuing effect on the normal pre-osteoblast cells. In conclusion, it can be stated that Zol nanoformulation can be used as a good platform for a sustained release system with minimum side effects to normal bone cells.

Alendronate/dexamethasone combination therapy worsens soft and hard tissue wound healing around implants in rat maxillae

Dental implant treatment in patients prescribed medications is associated with bisphosphonate-related osteonecrosis of the jaw (BRONJ) around the implants. However, there is no scientific information on how bisphosphonate and/or steroid therapies affect wound healing around implants after implant placement. The aim of this study was to histopathologically and immunopathologically investigate the effects of bisphosphonate and/or steroid therapy on the early stages of soft and hard tissue wound healing around implants in rat maxillae. Eight-week-old female Wistar rats were used. Alendronate (ALN) monotherapy, dexamethasone (DEX) monotherapy, and ALN/DEX combination therapy were started 4 weeks after tooth extraction of right maxillary first molars. Saline was used as a control (n = 14/group). Implant placement was carried out after grossly and manually confirming no open wounds at 16 weeks post-extraction. Euthanasia was performed at 18 weeks post-extraction. Microcomputed tomography, histological stains and immunostaining to detect blood vessels and macrophages were performed to quantitatively analyze wound healing around implants. ALN/DEX combination therapy significantly increased necrotic bone with more empty lacunae and polymorphonuclear cell infiltration with open wounds when compared with all other therapy groups. Necrotic bone was broadly distributed from the crestal bone to the lower area near the apex of the implants in the ALN/DEX group. Interestingly, both ALN/DEX combination therapy and DEX monotherapy significantly increased the number of CD68⁺NG2^- macrophages, whereas only ALN/DEX combination therapy, not DEX monotherapy, significantly shifted the M1/M2 ratio to M1 by significant increases in M1 macrophages and unchanged M2 macrophages in the connective tissue around implants. Within the limitations of this study, these findings may contribute to understanding the early stages of the histopathology and immunopathology of BRONJ-like lesions around dental implants. Continuous accumulation of M1 macrophages without alteration of M2 macrophages may be associated with developing BRONJ around implants.

Medication-related osteonecrosis and osteoradionecrosis of the jaws: Update and current management

Medication related osteonecrosis of the jaws (MRONJ) and osteoradionecrosis of the jaws (ORNJ) are two different diseases of quite similar appearance. MRONJ is mainly due to antiresorptive or antiangiogenic drug therapy and ORNJ to radiotherapy. The present work aimed at presenting and comparing the current knowledge on MRONJ and ORNJ. They both present as an exposure of necrotic bone and differ in some clinical or radiological characteristics, clinical course and mostly in treatment. They share similar risk factors. A tooth extraction is more frequently found as a triggering factor in MRONJ. The frequency of a maxillary localisation seems higher for MRONJ. On computed tomographic images, a periosteal reaction seems characteristic of MRONJ. More frequent pathological fractures seem to occur in ORNJ. It is mandatory, for ORNJ diagnosis, to exclude a residual or recurrent tumour using histological examination. Both MRONJ and ORNJ are challenging to treat and cannot be managed similarly. For both, it would still be worth to optimise awareness within the medical community, patients' oral hygiene and dental cares to improve their prevention and make their incidences decrease. Conservative therapy is more frequently achieved for MRONJ than ORNJ and surgical resection is more often performed for ORNJ. For both diseases, the last treatment possible in refractory cases is a surgical extensive resection with free flap reconstruction. A MRONJ classification is widely used today, whereas no consensus exists to date for ORNJ classification. We propose a classification that could play this role.

Borate bioactive glass prevents zoledronate-induced osteonecrosis of the jaw by restoring osteogenesis and angiogenesis

OBJECTIVES

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a severe complication of systemic nitrogen-containing bisphosphonate (N-BP) administration, which leads to osteonecrosis, pain, and infection. Despite much effort, effective remedies are yet to be established. This study aimed to investigate potential recovery effect of borate bioactive glass (BBG) in vitro and in vivo.

METHODS

The effect of BBG on zoledronate-treated bone marrow mesenchymal cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) was explored by cell counting kit-8, EdU assay, flow cytometry, alkaline phosphatase staining, alizarin red staining, angiogenesis experiment, and real-time quantitative polymerase chain reaction. The preventive effect of BBG on zoledronate-induced osteonecrosis of the jaw in rat model was examined by micro-CT, HE staining, and immunohistochemistry.

RESULTS

Exposure of BBG to BMSCs and HUVECs increased cell proliferation and restored their osteogenesis and angiogenesis potential in vitro. The BRONJ lesions were satisfactorily repaired and bone mineral density, bone volume/tissue volume, trabecula number, OCN-positive cells, and CD31-positive cells were increased in the BBG-treated groups compared with saline-treated groups.

CONCLUSIONS

Exposure of BMSCs and HUVECs to BBG restores osteogenesis and angiogenesis inhibited by zoledronate. BBG successfully restores extraction socket healing of BRONJ in rat model.

Effect of alendronate or 8-prenylnaringenin applied as a single therapy or in combination with vibration on muscle structure and bone healing in ovariectomized rats

Bisphosphonate alendronate (ALN), phytoestrogen 8-prenylnaringenin (8-PN) and the whole body vibration exert a favorable effect on osteoporotic bone. However, the impact of these treatments and the combination of pharmacological therapies with biomechanical stimulation on muscle and bone has not yet been explored in detail. The effect of ALN and 8-PN and their combination with the vibration (Vib) on skeletal muscle and bone healing was investigated in ovariectomized (Ovx) rats.

Three-month old rats were Ovx (n = 78), or left intact (Non-Ovx; n = 12). Five weeks after Ovx, all rats were treated according to the group assignment (n = 12/13): 1) Non-Ovx; 2) Ovx; 3) Ovx + Vib; 4) Ovx + ALN; 5) Ovx + ALN + Vib; 6): Ovx + 8-PN; 7) Ovx + 8-PN + Vib. Treatments with ALN (0.58 mg/kg BW, in food), 8-PN (1.77 mg/kg BW, daily s.c. injections) and/or with vertical vibration (0.5 mm, 35 Hz, 1 g, 15 min, 2×/day, 5×/week) were conducted for ten weeks. Nine weeks after Ovx, all rats underwent bilateral tibia osteotomy with plate osteosynthesis and were sacrificed six weeks later.

Vibration increased fiber size and capillary density in muscle, enlarged callus area and width, and decreased callus density in tibia, and elevated alkaline phosphatase in serum. ALN and ALN + Vib enhanced capillarization and lactate dehydrogenase activity in muscle. In tibia, ALN slowed bone healing, ALN + Vib increased callus width and density, enhanced callus formation rate and expression of osteogenic genes. 8-PN and 8-PN + Vib decreased fiber size and increased capillary density in muscle; callus density and cortical width were reduced in tibia. Vibration worsened 8-PN effect on bone healing decreasing the callus width and area.

Our data suggest that Vib, ALN, 8-PN, or 8-PN + Vib do not appear to aid bone healing. ALN + Vib improved bone healing; however application is questionable since single treatments impaired bone healing. Muscle responds to the anti-osteoporosis treatments and should be included in the evaluation of the drugs.

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Vibration (Vib) was beneficial for muscle structure, it tended to interfere with early bone healing.

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Alendronate (ALN) enhanced capillary density and metabolism in muscle, slowed bone healing.

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8-Prenylnaringenin (8-PN) had favorable effects on muscle, for bone healing it was disadvantageous.

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8PN + Vib further worsened 8-PN effect on bone, ALN + Vib improved bone healing.

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Muscles respond to anti-osteoporosis treatments, their analysis should be included in the evaluation of drugs.

Bone mineralization and vascularization in bisphosphonate-related osteonecrosis of the jaw: an experimental study in the rat

OBJECTIVES

Pathogenesis of bisphosphonate-related osteonecrosis of the jaws (BRONJ) is not fully explained. An antiangiogenic effect of bisphosphonates (BPs) or an altered bone quality have been advocated. The aims of the present study were to analyze alveolar mandibular vascularization and bone quality in rats with BRONJ.

MATERIALS AND METHODS

Thirty-eight Sprague-Dawley rats were randomized into two groups: zoledronic acid (ZA), n = 27, and control (CTRL) n = 11. The ZA group received a weekly IV injection of ZA (100 μg/kg) during 10 weeks. The CTRL group received saline. After 6 weeks, extraction of the right mandibular molars was performed. Rats were sacrificed after 14 weeks. Microtomography characterized bone lesions and vascularization after injection of a radio-opaque material. Raman microspectroscopy evaluated bone mineralization.

RESULTS

Fifty-five percent of ZA rats presented bone exposure and signs of BRONJ. None sign was found at the left hemimandible in the ZA group and in the CTRL group. Vascular density appeared significantly increased in the right hemimandibles of the CTRL group compared to the left hemimandibles. Vascularization was reduced in the ZA group. A significantly increased of the mineral-to-amide ratio was found in the alveolar bone of ZA rats by Raman microspectroscopy.

CONCLUSIONS

In a rat model of BRONJ, microtomography evidenced osteonecrosis in BRONJ. Raman spectroscopy showed an increased mineralization. Vascularization after tooth extraction was impaired by ZA.

CLINICAL RELEVANCE

Prolonged BP administration caused an increase in the mineralization and a quantitative reduction of the vascularization in the alveolar bone; both factors might be involved concomitantly in the BRONJ pathophysiology.

Zoledronate suppresses VEGF‑induced capillary tube formation and inhibits expression of interferon‑induced transmembrane protein‑1 in human umbilical vein endothelial cells

Interferon‑induced transmembrane protein 1 (IFITM1) is a member of the interferon‑induced transmembrane protein family and has recently been identified as a novel protein participant in angiogenesis. Zoledronate (ZON), a nitrogen‑containing bisphosphonate, is widely used in the treatment of osteoporosis and to prevent bone metastases of certain cancer types. However, the association between ZON and IFITM1 has remained elusive. The present study investigated the effect of ZON on the expression of IFITM1 during vascular endothelial growth factor (VEGF)‑induced capillary tube formation in human umbilical vein endothelial cells. It was observed that cell proliferation and VEGF‑induced tube formation were significantly inhibited by treatment with 10 µM ZON. The expression of IFITM1 increased during VEGF‑induced tube formation. However, the VEGF‑induced increase in IFITM1 expression exhibited a dose‑ and time‑dependent decrease with ZON treatment at the mRNA and protein level. Furthermore, matrix metalloproteinase‑9 activation was markedly decreased by ZON treatment. These results suggest that induction of IFITM1 expression may be involved in the anti‑angiogenic activity of ZON.

[Research progress on bisphosphonate-related osteonecrosis of the jaws]

Bisphosphonates (BPs), as potent drugs inhibiting bone resorption, have been widely used for treatment of several diseases. In recent years, dentists and oral and maxillofacial surgeons reported continuously increasing cases of bisphosphonate-related osteonecrosis of the jaws (BRONJ). This disease is clinically characterized by exposed bones, formation of sequestrum, pain, and halitosis. Provided that pathogenesis of BRONJ is unclear, effective treatments for this disease are currently unavailable. Thus, prevention plays an important role in the management of BRONJ. This review summarizes research progress on pathogenesis, risk factors, clinical characteristics, treatment, and prevention of this condition.

Histopathological features of bone regeneration in a canine segmental ulnar defect model

Background

Today, finding an ideal biomaterial to treat the large bone defects, delayed unions and non-unions remains a challenge for orthopaedic surgeions and researchers. Several studies have been carried out on the subject of bone regeneration, each having its own advantages. The present study has been designed in vivo to evaluate the effects of cellular auto-transplantation of tail vertebrae on healing of experimental critical bone defect in a dog model.

Methods

Six indigenous breeds of dog with 32 ± 3.6 kg average weight from both sexes (5 males and 1 female) received bilateral critical-sized ulnar segmental defects. After determining the health condition, divided to 2 groups: The Group I were kept as control I (n = 1) while in Group II (experimental group; n = 5) bioactive bone implants were inserted. The defects were implanted with either autogeneic coccygeal bone grafts in dogs with 3-4 cm diaphyseal defects in the ulna. Defects were stabilized with internal plate fixation, and the control defects were not stabilized. Animals were euthanized at 16 weeks and analyzed by histopathology.

Results

Histological evaluation of this new bone at sixteen weeks postoperatively revealed primarily lamellar bone, with the formation of new cortices and normal-appearing marrow elements. And also reformation cortical compartment and reconstitution of marrow space were observed at the graft-host interface together with graft resorption and necrosis responses. Finally, our data were consistent with the osteoconducting function of the tail autograft.

Conclusions

Our results suggested that the tail vertebrae autograft seemed to be a new source of autogenous cortical bone in order to supporting segmental long bone defects in dogs. Furthermore, cellular autotransplantation was found to be a successful replacement for the tail vertebrae allograft bone at 3-4 cm segmental defects in the canine mid- ulna. Clinical application using graft expanders or bone autotransplantation should be used carefully and requires further investigation.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2028232688119271.

Bisphosphonate related osteonecrosis of the jaw: a study of 18 cases associated with fungal infection

Osteonecrosis of the jaw (ONJ) is a serious complication associated with oral and intravenous bisphosphonate therapy. Its pathogenesis is not well understood and its management is difficult. Microbiological investigations have detected a variety of oral pathogens such as Actinomyces, Enterococcus, Candida albicans, Aspergillus, Haemophilus influenzae, alpha-hemolytic streptococci, Lactobacillus, Enterobacter, and Klebsiella pneumoniae. To better treat it, it is important to understand its causes and complications. Materials and Methods. Our present study addresses a microscopic observation of curetted jaw necrotic lesions related to bisphosphonates. Results. A mycotic infestation has been found in all of the 18 cases studied. Discussion. An identification of the fungal agent and its incrimination in the pathogenesis of bisphosphonates related osteonecrosis of the jaw could change radically the management of this condition.

Bone Health in Patients with Breast Cancer: Recommendations from an Evidence-Based Canadian Guideline

Bone loss is common in patients with breast cancer. Bone modifying agents (BMAs), such as bisphosphonates and denosumab, have been shown to reverse or stabilize bone loss and may be useful in the primary and metastatic settings. The purpose of this review is to provide clear evidence-based strategies for the management of bone loss and its symptoms in breast cancer. A systematic review of clinical trials and meta-analyses published between 1996 and 2012 was conducted of MEDLINE and EMBASE. Reference lists were hand-searched for additional publications. Recommendations were developed based on the best available evidence. Zoledronate, pamidronate, clodronate, and denosumab are recommended for metastatic breast cancer patients; however, no one agent can be recommended over another. Zoledronate or any oral bisphosphonate and denosumab should be considered in primary breast cancer patients who are postmenopausal on aromatase inhibitor therapy and have a high risk of fracture and/or a low bone mineral density and in premenopausal primary breast cancer patients who become amenorrheic after therapy. No one agent can be recommended over another. BMAs are not currently recommended as adjuvant therapy in primary breast cancer for the purpose of improving survival, although a major Early Breast Cancer Cooperative Trialists’ Group meta-analysis is underway which may impact future practice. Adverse events can be managed with appropriate supportive care.

Association of a polymorphism in PON-1 gene with steroid-induced osteonecrosis of femoral head in Chinese Han population

Background

Treatment with steroids covers a wide spectrum of diseases in clinic. However, some users are suffering from serious side effects of steroid administration, while we enjoy the benefit it brings about. Osteonecrosis of the femoral head (ONFH) is a troublesome one among them. Recent studies have demonstrated that lipid metabolism disorder may play a vital role in pathogenesis of ONFH and mutation of the paraoxonase-1 (PON-1) gene may be involved in the occurrence of this disease. However, the relationship between polymorphisms of PON-1 and ONFH has not been thoroughly studied. The aim of this study was to determine whether PON-1 polymorphisms are associated with steroid-induced ONFH through a cohort study among Chinese Han population.

Methods

This trial applied a case–control scheme to compare the clinical data including PON-1 SNP among 94 patients and 106 control subjects to analyze the association between SNP and risk of steroid-induced ONFH. Time of Flight Mass Spectrometer is utilized for genotyping and the result was analyzed in multivariate analysis models.

Results

According to polymorphism test of rs662, its SNP was significantly associated with the risk of ONFH in overdominant analysis model [P value: 0.022; odds ratio (OR): 0.39]. However, genotype frequencies of rs662 of PON-1 gene between case and control group showed no differences (P > 0.05).

Conclusions

Our data suggest for the first time that SNP (rs662) of the PON-1 gene was associated with the risk of steroid-induced ONFH. In addition, PAI-1 SNPs may play an important role in pathogenesis of ONFH.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticphatology.diagnomx.eu/vs/1501829501107336.

Genetic polymorphisms in plasminogen activator inhibitor-1 predict susceptibility to steroid-induced osteonecrosis of the femoral head in Chinese population

Background

Steroid usage has been considered as a leading cause of non-traumatic osteonecrosis of the femoral head (ONFH), which is involved in hypo-fibrinolysis and blood supply interruption. Genetic polymorphisms in plasminogen activator inhibitor-1 (PAI-1) have been demonstrated to be associated with ONFH risk in several populations. However, this relationship has not been established in Chinese population. The aim of this study was to investigate the association of PAI-1 gene polymorphisms with steroid-induced ONFH in a large cohort of Chinese population.

Methods

A case–control study was conducted, which included 94 and 106 unrelated patients after steroid administration recruited from 14 provinces in China, respectively. Two SNPs (rs11178 and rs2227631) within PAI-1 were genotyped using Sequenom MassARRAY system.

Results

rs2227631 SNP was significantly associated with steroid-induced ONFH group in codominant (P = 0.04) and recessive (P = 0.02) models. However, there were no differences found in genotype frequencies of rs11178 SNP between controls and patients with steroid-induced ONFH (all P > 0.05).

Conclusions

Our data offer the convincing evidence for the first time that rs2227631 SNP of PAI-1 may be associated with the risk of steroid-induced ONFH, suggesting that the genetic variations of this gene may play an important role in the disease development.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1569909986109783.

Risk of osteonecrosis of the jaw in cancer patients receiving denosumab: a meta-analysis of seven randomized controlled trials

AIMS

The aim of this study is to gain a better understanding of the overall incidence and risk of osteonecrosis of the jaw (ONJ) in cancer patients receiving denosumab.

METHODS

We performed a meta-analysis of relevant randomized controlled trials identified in Pubmed, Embase, and Cochrane databases. Abstracts presented at the conferences were also searched. Overall incidence rates, relative risk (RR), and 95 % confidence intervals (CI) were calculated employing fixed- or random-effects models depending on the heterogeneity of the included trials.

RESULTS

A total of 8963 patients with a variety of solid tumors from 7 randomized controlled trials (RCTs) were included for the meta-analysis. The overall incidence of ONJ in cancer patients receiving denosumab was 1.7 % [95 % CI: 0.9-3.1 %]. Also, the use of denosumab was associated with significantly increased risk of ONJ in comparison with bisphosphonates (BPs)/placebo treatment (RR 1.61, 95 % CI: 1.05-2.48, P = 0.029). Subgroup analysis based on controlled therapies demonstrated an increased risk of ONJ in denosumab therapy, when compared with BPs (RR 1.48, 95 % CI: 0.96-2.29, P = 0.078) or placebo (RR 16.28, 95 % CI: 1.68-158.05, P = 0.017). Similar results were observed in prostate cancer (RR 3.358, 95 % CI: 1.573-7.166, P = 0.002) while there was a non-significantly increased risk of denosumab-related osteonecrosis of the jaw (DONJ) in non-prostate cancers (RR 1.142, 95 % CI: 0.678-1.921, P = 0.618).

CONCLUSIONS

The use of denosumab is associated with an increased risk of developing ONJ when compared with BP treatment or placebo, although the increased risk was not statistically significant between denosumab and BP treatment. Further studies are still needed to establish guidelines for the prevention and effective treatment of ONJ.

The treatment effect of porous titanium alloy rod on the early stage talar osteonecrosis of sheep

Osteonecrosis of the talus (ONT) may severely affect the function of the ankle joint. Most orthopedists believe that ONT should be treated at an early stage, but a concise and effective surgical treatment is lacking. In this study, porous titanium alloy rods were prepared and implanted into the tali of sheep with early-stage ONT (IM group). The curative effect of the rods was compared to treatment by core decompression (DC group). No significant differences in bone reconstruction were observed between the two groups at 1 month after intervention. After 3 months, the macroscopic view of gross specimens of the IM group showed ordinary contours, but the specimens of the DC group showed obvious partial bone defects and cartilage degeneration. Quantitative analysis of the reconstructed trabeculae by micro-CT and histological study suggested that the curative effect of the IM group was superior to that of the DC group at 3 months after intervention. These favorable short-term results of the implantation of porous titanium alloy rods into the tali of sheep with early-stage ONT may provide insight into an innovative surgical treatment for ONT.