Bench to bedside: elucidation of the OPG-RANK-RANKL pathway and the development of denosumab

A Comprehensive Review of Interventional Clinical Trials in Patients with Bone Metastases

Bone metastasis is one of the most important factors associated with poor prognosis for patients with prostate, breast, thyroid, and lung cancer. In the past two decades, 651 clinical trials, including 554 interventional trials, were being registered in ClinicalTrials.gov and pharma.id.informa.com to combat bone metastases from different perspectives. In this review, we comprehensively analyzed, regrouped, and discussed all the interventional trials on bone metastases. Clinical trials were re-grouped into bone-targeting agents, radiotherapy, small molecule targeted therapy, combination therapy, and others, based on the different mechanisms of action including modifying the bone microenvironment and preventing the growth of cancer cells. We also discussed the potential strategies that might improve overall survival and progression-free survival of patients with bone metastases in the future.

TRPS1 regulates the opposite effect of progesterone via RANKL in endometrial carcinoma and breast carcinoma

Medroxyprogesterone (MPA) has therapeutic effect on endometrial carcinoma (EC), while it could promote the carcinogenesis of breast cancer (BC) by activating receptor activator of NF-kB ligand (RANKL). However, the selective mechanism of MPA in endometrium and breast tissue remains obscure. Multiomics analysis of chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq) were performed in cell lines derived from endometrial cancer and mammary tumor to screen the differential co-regulatory factors of progesterone receptor (PR). Dual-luciferase assays and ChIP-PCR assays were used to validate the transcriptional regulation. Co-immunoprecipitation (Co-IP) and immunofluorescence assays were carried out to explore molecular interactions between PR, the cofactor transcriptional repressor GATA binding 1 (TRPS1), and histone deacetylase 2 (HDAC2). Subsequently, human endometrial cancer/breast cancer xenograft models were established to investigate the regulation effect of cofactor TRPS1 in vivo. In the current study, we found that MPA downregulated RANKL expression in a time- and dose-dependent manner in EC, while had the opposite effect on BC. Then PR could recruit cofactor TRPS1 to the promoter of RANKL, leading to histone deacetylation of RANKL to repress its transcription in EC, whereas MPA disassociated the PR/TRPS1/HDAC2 complex to enhance RANKL histone acetylation in BC. Therefore, TRPS1, the coregulator recruited by PR played a critical role in the selective mechanism of progesterone in EC and BC and could become a potential candidate for targeted therapy to improve the anticancer effect of MPA on EC and avoid its carcinogenic effect on BC.

RANKL and RANK in Cancer Therapy

Receptor activator of nuclear factor-κB (RANK) and its ligand (RANKL) are key regulators of mammalian physiology such as bone metabolism, immune tolerance and antitumor immunity, and mammary gland biology. Here, we explore the multiple functions of RANKL/RANK in physiology and pathophysiology and discuss underlying principles and strategies to modulate the RANKL/RANK pathway as a therapeutic target in immune-mediated cancer treatment.

Denosumab and incidence of type 2 diabetes among adults with osteoporosis: population based cohort study

OBJECTIVE

To estimate the effect of denosumab compared with oral bisphosphonates on reducing the risk of type 2 diabetes in adults with osteoporosis.

DESIGN

Population based study involving emulation of a randomized target trial using electronic health records.

SETTING

IQVIA Medical Research Data primary care database in the United Kingdom, 1995-2021.

PARTICIPANTS

Adults aged 45 years or older who used denosumab or an oral bisphosphonate for osteoporosis.

MAIN OUTCOME MEASURES

The primary outcome was incident type 2 diabetes, as defined by diagnostic codes. Cox proportional hazards models were used to estimate adjusted hazard ratios and 95% confidence intervals, comparing denosumab with oral bisphosphonates using an as treated approach.

RESULTS

4301 new users of denosumab were matched on propensity score to 21 038 users of an oral bisphosphonate and followed for a mean of 2.2 years. The incidence rate of type 2 diabetes in denosumab users was 5.7 (95% confidence interval 4.3 to 7.3) per 1000 person years and in oral bisphosphonate users was 8.3 (7.4 to 9.2) per 1000 person years. Initiation of denosumab was associated with a reduced risk of type 2 diabetes (hazard ratio 0.68, 95% confidence interval 0.52 to 0.89). Participants with prediabetes appeared to benefit more from denosumab compared with an oral bisphosphonate (hazard ratio 0.54, 0.35 to 0.82), as did those with a body mass index ≥30 (0.65, 0.40 to 1.06).

CONCLUSIONS

In this population based study, denosumab use was associated with a lower risk of incident type 2 diabetes compared with oral bisphosphonate use in adults with osteoporosis. This study provides evidence at a population level that denosumab may have added benefits for glucose metabolism compared with oral bisphosphonates.

CCL12 induces trabecular bone loss by stimulating RANKL production in BMSCs during acute lung injury

In the last three years, the capacity of health care systems and the public health policies of governments worldwide were challenged by the spread of SARS-CoV-2. Mortality due to SARS-CoV-2 mainly resulted from the development of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Moreover, millions of people who survived ALI/ARDS in SARS-CoV-2 infection suffer from multiple lung inflammation-induced complications that lead to disability and even death. The lung-bone axis refers to the relationship between lung inflammatory diseases (COPD, asthma, and cystic fibrosis) and bone diseases, including osteopenia/osteoporosis. Compared to chronic lung diseases, the influence of ALI on the skeleton has not been investigated until now. Therefore, we investigated the effect of ALI on bone phenotypes in mice to elucidate the underlying mechanisms. In vivo bone resorption enhancement and trabecular bone loss were observed in LPS-induced ALI mice. Moreover, chemokine (C-C motif) ligand 12 (CCL12) accumulated in the serum and bone marrow. In vivo global ablation of CCL12 or conditional ablation of CCR2 in bone marrow stromal cells (BMSCs) inhibited bone resorption and abrogated trabecular bone loss in ALI mice. Furthermore, we provided evidence that CCL12 promoted bone resorption by stimulating RANKL production in BMSCs, and the CCR2/Jak2/STAT4 axis played an essential role in this process. Our study provides information regarding the pathogenesis of ALI and lays the groundwork for future research to identify new targets to treat lung inflammation-induced bone loss.

Periplocin targets low density lipoprotein receptor-related protein 4 to attenuate osteoclastogenesis and protect against osteoporosis

Osteoporosis is a common inflammaging-related condition, where long-term accumulation of pro-inflammatory cytokines causes massive bone loss. Periplocin, a cardiotonic steroid isolated from Periploca forrestii, has been proved to reduce inflammation in several inflammatory diseases, such as rheumatoid arthritis. However, its effect and mechanism of inflammation in osteoporosis, in which pro-inflammatory factors accelerate bone loss, has not been well demonstrated. In this study, periplocin attenuated receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation of bone marrow-derived macrophages (BMMs) and RAW264.7 cells in vitro. It reduced osteoclast numbers and bone resorption in a concentration- and time-dependent manner. Further, periplocin treatment resulted in reduced bone loss on mice with ovariectomy-induced osteoporosis in vivo. By transcriptome sequencing, periplocin was indicated to function through inhibition of the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways and attenuating interactions between NF-κB and nuclear factor of activated T-cells 1 (NFATc1). It was further detected to bind low density lipoprotein receptor-related protein 4 (LRP4) in osteoclasts to exert anti-inflammatory and anti-osteoclastic effects. Overall, the findings have highlighted a better understanding for the anti-inflammatory and anti-osteoclastic role of periplocin in osteoporosis and its mechanism, bringing new possibilities for osteoporosis treatment.

Effects of anti-RANKL antibodies administered to pregnant mice on bone and tooth development in neonates

OBJECTIVES

This study examined how the anti-bone resorptive agent denosumab, which comprises anti-receptor activator of nuclear factor kappa B ligand (anti-RANKL) monoclonal antibodies, administered during pregnancy affected neonatal development. Anti-RANKL antibodies, which are known to bind to mouse RANKL and inhibit osteoclast formation, were administered to pregnant mice. Following this, the survival, growth, bone mineralization, and tooth development of their neonates were analyzed.

METHODS

Anti-RANKL antibodies (5 mg/kg) were injected into pregnant mice on day 17 of gestation. After parturition, their neonatal offspring underwent microcomputed tomography at 24 h and at 2, 4, and 6 weeks after birth. Three-dimensional bone and teeth images were subjected to histological analysis.

RESULTS

Approximately 70% of the neonatal mice born to mice who received anti-RANKL antibodies died within 6 weeks after birth. These mice had a significantly lower body weight and significantly higher bone mass compared with the control group. Furthermore, delayed tooth eruption and abnormal tooth morphology (eruption length, enamel surface, and cusps) were observed. Conversely, while the tooth germ shape and mothers against decapentaplegic homolog 1/5/8 expression remained unchanged at 24 h after birth in the neonatal mice born to mice that received anti-RANKL antibodies, osteoclasts were not formed.

CONCLUSIONS

These results suggest that anti-RANKL antibodies administered to mice in the late stage of pregnancy results in adverse events in their neonatal offspring. Thus, it is speculated that administering denosumab to pregnant humans will affect fetal development and growth after birth.

Changes in RANKL and TRAcP 5b after discontinuation of denosumab suggest RANKL mediated formation of osteoclasts results in the increased bone resorption

In patients discontinuing long-term denosumab, RANKL levels are high 6 months after the last denosumab injection. Nine and 12 months after the last denosumab injection RANKL levels are lower, but TRAcP 5b levels are higher, suggesting that accumulated RANKL increases the number of active osteoclasts.

PURPOSE

The rapid increase in bone turnover occurring when discontinuing long-term treatment with denosumab (DMAB), an antibody that neutralizes receptor activator of nuclear factor kappa-B ligand (RANKL) is not fully understood. We aimed to investigate the mechanisms underlying the rebound activation of bone resorption by measuring tartrate-resistant acid phosphatase 5b (TRAcP 5b), RANKL, osteoprotegerin (OPG), C-terminal collagen crosslinks (CTX), and procollagen type I N-propeptide (P1NP) in patients discontinuing long-term DMAB.

METHODS

Sixty-one patients with BMD T-score > - 2.5 at the spine and hip discontinuing long-term DMAB were randomized to treatment with zoledronate (ZOL) 6 months (6 M group, n = 20), 9 months (9 M group, n = 20) or 12 months after the last DMAB injection or when bone turnover was high (12 M group, n = 21). Bone turnover markers were measured immediately before initiation of ZOL treatment.

RESULTS

We found higher CTX and PINP in the 9 M and 12 M groups compared to the 6 M group (p < 0.001). In the 6 M group, TRAcP 5b was lower and RANKL higher than in the other two groups (p < 0.001). TRAcP 5b correlated negatively with RANKL (R = - 0.54), and time since the last DMAB injection correlated positively with CTX (R = 0.56), PINP (R = 0.72), TRAcP 5b (R = 0.51) and negatively with RANKL (R = - 0.70) (p < 0.001 for all). We found no difference in OPG between groups.

CONCLUSION

Following discontinuation of long-term DMAB, we find high levels of RANKL, which most likely result in an increase in the number of active osteoclasts (illustrated by TRAcP5b) causing an increased bone turnover.

Dual Role of Interleukin-20 in Different Stages of Osteoclast Differentiation and Its Osteoimmune Regulation during Alveolar Bone Remodeling

Osteoimmunology mediators are critical to balance osteoblastogenesis and osteoclastogenesis to maintain bone homeostasis. A lot of the osteoimmunology mediators are regulated by interleukin-20 (IL-20). However, little is known about the role of IL-20 in bone remodeling. Here, we showed that IL-20 expression was correlated with osteoclast (OC) activity in remodeled alveolar bone during orthodontic tooth movement (OTM). Ovariectomize (OVX) in rats promoted OC activity and enhanced IL-20 expression, while blocking OC inhibited IL-20 expression in osteoclasts. In vitro, IL-20 treatment promoted survival, inhibited apoptosis of the preosteoclast at the early stages of osteoclast differentiation, and boosted the formation of osteoclasts and their bone resorption function at the late stages. More importantly, anti-IL-20 antibody treatment blocked IL-20-induced osteoclastogenesis and the subsequent bone resorption function. Mechanistically, we showed that IL-20 synergistically acts with RANKL to activate the NF-κB signaling pathway to promote the expression of c-Fos and NFATc1 to promote osteoclastogenesis. Moreover, we found that local injection of IL-20 or anti-IL-20 antibody enhanced osteoclast activity and accelerated OTM in rats, while blocking IL-20 reversed this phenomenon. This study revealed a previously unknown role of IL-20 in regulating alveolar bone remodeling and implies the application of IL-20 to accelerated OTM.

Current comprehensive understanding of denosumab (the RANKL neutralizing antibody) in the treatment of bone metastasis of malignant tumors, including pharmacological mechanism and clinical trials

Denosumab, a fully humanized monoclonal neutralizing antibody, inhibits activation of the RANK/RANKL/OPG signaling pathway through competitive binding with RANKL, thereby inhibiting osteoclast-mediated bone resorption. Denosumab inhibits bone loss; therefore, it is used to treat metabolic bone diseases (including postmenopausal osteoporosis, male osteoporosis, and glucocorticoid-induced osteoporosis), in clinical practice. Since then, multiple effects of denosumab have been discovered. A growing body of evidence suggests that denosumab has a variety of pharmacological activities and broad potential in clinical diseases such as osteoarthritis, bone tumors, and other autoimmune diseases. Currently, Denosumab is emerging as a treatment for patients with malignancy bone metastases, and it also shows direct or indirect anti-tumor effects in preclinical models and clinical applications. However, as an innovative drug, its clinical use for bone metastasis of malignant tumors is still insufficient, and its mechanism of action needs to be further investigated. This review systematically summarizes the pharmacological mechanism of action of denosumab and the current understanding and clinical practice of the use of denosumab for bone metastasis of malignant tumors to help clinicians and researchers deepen their understanding of denosumab.

Astragalus Polysaccharides Alleviate Lung Adenocarcinoma Bone Metastases by Inhibiting the CaSR/PTHrP Signaling Pathway

Bone metastasis is one of the common complications of lung cancer and can lead to bone-related adverse events, such as pathological fractures, spinal cord defects, and nerve compression syndrome. As an effective medicinal component of Astragalus membranaceus, Astragalus polysaccharide (APS) has antitumor activity and alleviates osteoporosis to a certain extent. In this study, we explored the possible role and mechanism underlying APS inhibition of lung adenocarcinoma bone metastases by constructing a mouse model of lung adenocarcinoma bone metastases. First, we constructed osteoclast (OC) and osteoblast (OB) culture systems in vitro to confirm that APS affected the differentiation and function of OCs and OBs. Then, using the mouse bone metastasis model, microCT, and bone histopathology, we confirmed that APS inhibited osteolytic metastasis and tumor cell proliferation in mice, and the effect was mainly realized by inhibiting the CaSR/PTHrP signal pathway. The results showed that APS had a protective effect on lung adenocarcinoma bone metastases.

Denosumab Discontinuation

PURPOSE OF REVIEW

To review the pathophysiology, the clinical consequences as well as way of mitigating the effects of denosumab discontinuation.

RECENT FINDINGS

Treatment with denosumab (DMAB) is reversible and upon discontinuation there is a rapid increase in bone turnover and a subsequent bone loss. During this phase of high bone turnover, an increased risk of fractures has been reported. Therefore, treatment with DMAB could be considered life-long. However, side-effects may prompt the need for discontinuation and moreover, treatment with DMAB may have increased BMD to levels where continuing treatment does not provide further fracture risk reduction. Patients stopping DMAB should be offered subsequent antiresorptive treatment with an intense monitoring regimen during the initial year as most of the bone loss occurs within these initial 12 months. In this review, we evaluated the literature published over the past 1 to 3 years investigating DMAB withdrawal with focus on bone turnover markers, bone mineral density, and fracture risk and the transition to other anti-osteoporosis therapies. Furthermore, we summarized the current recommendations of international guidelines. In this review, we evaluated the literature published over the past 1 to 3 years investigating denosumab (DMAB) discontinuation and the transition to other anti-osteoporosis therapies. Additionally, we summarized the current recommendations of international guidelines.

Discontinuation of denosumab in men with prostate cancer

In patients with non-metastatic prostate cancer, treated with radiation therapy and androgen deprivation therapy for 3 years and DMAB on average for 5 years, BMD was in the normal or osteopenic range. Discontinuation of DMAB led to a bone loss of 2-5%. In men with osteopenia, the bone loss was prevented by zoledronate.

PURPOSE

Patients with prostate cancer receiving androgen deprivation therapy (ADT) are treated with denosumab (DMAB) to prevent fractures and preserve bone mass. We wanted to investigate the change in BMD in men with non-metastatic prostate cancer discontinuing DMAB.

METHODS

We conducted a retrospective cohort study based on medical records from patients referred to the Department of Endocrinology from the Department of Urology, Aarhus University Hospital between June 1, 2018, and June 1, 2021. We retrieved information on biochemistry and DXA performed 0-6 months after the last DMAB injection and a second DXA performed approximately 12 months after the first. In case of a BMD T-score ≤ - 1 at the lumbar spine or total hip at the first DXA, the patients were treated with zoledronate. The primary endpoint was change in lumbar spine BMD.

RESULTS

We included 50 patients with non-metastatic prostate cancer. The mean DMAB treatment duration was 5 ± 0.1 years. Among the patients treated with zoledronate (n = 9), BMD was maintained at the spine and femoral neck after a mean of 16 months. We found a significant decrease in BMD; - 4.9 ± 4.2%, - 1.9 ± 3.5%, and - 2.4 ± 3.6% at the spine, total hip, and femoral neck between the first and second DXA in the patients not treated with zoledronate (n = 24) (p ≤ 0.01 for all). One patient who did not receive ZOL sustained multiple fragility vertebral fractures after DMAB discontinuation.

CONCLUSION

In men with non-metastatic prostate cancer, discontinuation of DMAB after stopping ADT led to an average bone loss of 2-5%. Zoledronate prevented bone loss in men with osteopenia.

Clostridium butyricum Can Promote Bone Development by Regulating Lymphocyte Function in Layer Pullets

Bone health problems are a serious threat to laying hens; microbiome-based therapies, which are harmless and inexpensive, may be an effective solution for bone health problems. Here, we examined the impacts of supplementation with Clostridium butyricum (CB) on bone and immune homeostasis in pullets. The results of in vivo experiments showed that feeding the pullets CB was beneficial to the development of the tibia and upregulated the levels of the bone formation marker alkaline phosphatase and the marker gene runt-related transcription factor 2 (RUNX2). For the immune system, CB treatment significantly upregulated IL-10 expression and significantly increased the proportion of T regulatory (Treg) cells in the spleen and peripheral blood lymphocytes. In the in vitro test, adding CB culture supernatant or butyrate to the osteoblast culture system showed no significant effects on osteoblast bone formation, while adding lymphocyte culture supernatant significantly promoted bone formation. In addition, culture supernatants supplemented with treated lymphocytes (pretreated with CB culture supernatants) stimulated higher levels of bone formation. In sum, the addition of CB improved bone health by modulating cytokine expression and the ratio of Treg cells in the immune systems of layer pullets. Additionally, in vitro CB could promote the bone formation of laying hen osteoblasts through the mediation of lymphocytes.

Sexing Bones: Improving Transparency of Sex Reporting to Address Bias Within Preclinical Studies

Despite knowledge that sexually dimorphic mechanisms regulate bone homeostasis, sex often remains unreported and unconsidered in preclinical experimental design. Failure to report sex could lead to inappropriate generalizations of research findings and less effective translation into clinical practice. Preclinical sex bias (preferential selection of one sex) is present across other fields, including neuroscience and immunology, but remains uninvestigated in skeletal research. For context, we first summarized key literature describing sexually dimorphic bone phenotypes in mice. We then investigated sex reporting practices in skeletal research, specifically how customary it is for murine sex to be included in journal article titles or abstracts and then determined whether any bias in sex reporting exists. Because sex hormones are important regulators of bone health (gonadectomy procedures, ie, ovariectomy [OVX] and orchidectomy [ORX], are common yet typically not reported with sex), we incorporated reporting of OVX and ORX terms, representing female and male mice, respectively, into our investigations around sex bias. Between 1999 and 2020, inclusion of sex in titles or abstracts was low in murine skeletal studies (2.6%-4.06%). Reporting of OVX and ORX terms was low (1.44%-2.64%) and reporting of OVX and ORX with sex uncommon (0.4%-0.3%). When studies were combined to include both sexes and OVX (representing female) and ORX terms (representing male), a bias toward reporting of female mice was evident. However, when the terms OVX and ORX were removed, a bias toward the use of male mice was identified. Thus, studies focusing on sex hormones are biased toward female reporting with all other studies biased in reporting of male mice. We now call upon journal editors to introduce consistent guidance for transparent and accessible reporting of murine sex in skeletal research to better monitor preclinical sex bias, to diversify development of treatments for bone health, and to enable global skeletal health equity. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The effect of denosumab on disseminated tumor cells (DTCs) of breast cancer patients with neoadjuvant treatment: a GeparX translational substudy

Background

Disseminated tumor cells (DTCs) in the bone marrow are observed in about 40% at primary diagnosis of breast cancer and predict poor survival. While anti-resorptive therapy with bisphosphonates was shown to eradicate minimal residue disease in the bone marrow, the effect of denosumab on DTCs, particularly in the neoadjuvant setting, is largely unknown. The recent GeparX clinical trial reported that denosumab, applied as an add-on treatment to nab-paclitaxel based neoadjuvant chemotherapy (NACT), did not improve the patient’s pathologic complete response (pCR) rate. Herein, we analyzed the predictive value of DTCs for the response to NACT and interrogated whether neoadjuvant denosumab treatment may eradicate DTCs in the bone marrow.

Methods

A total of 167 patients from the GeparX trial were analyzed for DTCs at baseline by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3. Initially DTC-positive patients were re-analyzed for DTCs after NACT ± denosumab.

Results

At baseline, DTCs were observed in 43/167 patients (25.7%) in the total cohort, however their presence did not predict response to nab-paclitaxel based NACT (pCR rates: 37.1% in DTC-negative vs. 32.6% DTC-positive; p = 0.713). Regarding breast cancer subtypes, the presence of DTCs at baseline was numerically associated with response to NACT in TNBC patients (pCR rates: 40.0% in DTC-positive vs. 66.7% in DTC-negative patients; p = 0.16). Overall, denosumab treatment did not significantly increase the given DTC-eradication rate of NACT (NACT: 69.6% DTC-eradication vs. NACT + denosumab: 77.8% DTC-eradication; p = 0.726). In TNBC patients with pCR, a numerical but statistically non-significant increase of DTC-eradication after NACT + denosumab was observed (NACT: 75% DTC-eradication vs. NACT + denosumab: 100% DTC-eradication; p = 1.00).

Conclusion

This is the first study worldwide, demonstrating that neoadjuvant add-on denosumab over a short-term period of 24 months does not increase the DTC-eradication rate in breast cancer patients treated with NACT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-023-01619-2.

Causal effects for genetic variants of osteoprotegerin on the risk of acute myocardial infarction and coronary heart disease: A two-sample Mendelian randomization study

Although since the 1980s, the mortality of coronary heart disease(CHD) has obviously decreased due to the rise of coronary intervention, the mortality and disability of CHD were still high in some countries. Etiological studies of acute myocardial infarction(AMI) and CHD were extremely important. In this study, we used two-sample Mendelian randomization(TSMR) method to collect GWAS statistics of osteoprotegerin (OPG), AMI and CHD to reveal the causal relationship between OPG and these two diseases. In total, we identified 7 genetic variants associated with AMI and 7 genetic variants associated with CHD that were not found to be in linkage disequilibrium(LD; r ² < 0.001). Evidence of a positive effect of an OPG genetic susceptibility on AMI was discovered(IVW OR = 0.877; 95% CI = 0.787-0.977; p = 0.017; 7 SNPs) and CHD (IVW OR = 0.892; 95% CI = 0.803-0.991; p = 0.033; 7 SNPs). After removing the influence of rs1385492, we found that there was a correlation between OPG and AMI/CHD (AMI: weighted median OR = 0.818;95% CI = 0.724-0.950; p = 0.001; 6SNPs;CHD: weighted median OR = 0.842; 95% CI = 0.755-0.938; p = 1.893 × 10^-3; 6SNPs). The findings of our study indicated that OPG had a tight genetic causation association with MI or CHD. This genetic causal relationship presented us with fresh ideas for the etiology of AMI and CHD, which is an area of research that will continue in the future.

Bone Metastasis in Bladder Cancer

Bladder cancer (BCa) is the 10th most common and 13th most deadly malignancy worldwide. About 5% of BCa patients present initially with metastatic disease, with bone being the most diagnosed site for distant metastasis. The overall one-year survival of patients with BCa is 84%, whereas it is only 21% in patients with bone metastasis (BM). Metastasis of BCa cells to bone occurs by epithelial-to-mesenchymal transition, angiogenesis, intravasation, extravasation, and interactions with the bone microenvironment. However, the mechanism of BCa metastasis to the bone is not completely understood; it needs a further preclinical model to completely explain the process. As different imaging mechanisms, PET-CT cannot replace a radionuclide bone scan or an MRI for diagnosing BM. The management of BCa patients with BM includes chemotherapy, immunotherapy, targeted therapy, antibody-drug conjugates, bisphosphonates, denosumab, radioisotopes, and surgery. The objective of these treatments is to inhibit disease progression, improve overall survival, reduce skeletal-related events, relieve pain, and improve the quality of life of patients.

Modulating glycosphingolipid metabolism and autophagy improves outcomes in pre-clinical models of myeloma bone disease

Patients with multiple myeloma, an incurable malignancy of plasma cells, frequently develop osteolytic bone lesions that severely impact quality of life and clinical outcomes. Eliglustat, a U.S. Food and Drug Administration-approved glucosylceramide synthase inhibitor, reduced osteoclast-driven bone loss in preclinical in vivo models of myeloma. In combination with zoledronic acid, a bisphosphonate that treats myeloma bone disease, eliglustat provided further protection from bone loss. Autophagic degradation of TRAF3, a key step for osteoclast differentiation, was inhibited by eliglustat as evidenced by TRAF3 lysosomal and cytoplasmic accumulation. Eliglustat blocked autophagy by altering glycosphingolipid composition whilst restoration of missing glycosphingolipids rescued autophagy markers and TRAF3 degradation thus restoring osteoclastogenesis in bone marrow cells from myeloma patients. This work delineates both the mechanism by which glucosylceramide synthase inhibition prevents autophagic degradation of TRAF3 to reduce osteoclastogenesis as well as highlighting the clinical translational potential of eliglustat for the treatment of myeloma bone disease.

Osteoclast Recycling and the Rebound Phenomenon Following Denosumab Discontinuation

PURPOSE OF REVIEW

Inhibition of receptor activator of nuclear factor kappa-B ligand (RANKL) with denosumab is an effective treatment in a number of conditions including osteoporosis where suppression of bone resorption is desired. However, denosumab discontinuation is associated with rebound increase in bone resorption and subsequent loss in bone mass and a rapid return to baseline fracture risk. We review recent data on the rebound increase in bone resorption following denosumab discontinuation and the potential mechanisms behind this phenomenon.

RECENT FINDINGS

Osteoclasts have been considered to be highly specialised cells that undergo apoptosis after fulfilling their function of bone resorption. However, recent studies suggest that osteoclasts are longer lived cells which migrate through vasculature and are capable of undergoing fission into a novel cell type (the osteomorph) and re-fusion in a process termed osteoclast recycling. The life cycle of the osteoclast is more complex than previously appreciated. Osteoclast recycling provides a novel mechanistic framework to examine changes in osteoclast biology in response to treatment of bone diseases and provides an exciting new avenue towards personalised medicine.

Phosphatidylserine liposome multilayers mediate the M1-to-M2 macrophage polarization to enhance bone tissue regeneration

An appropriate immune microenvironment, governed by macrophages, is essential for rapid tissue regeneration after biomaterial implantation. The macrophage phenotypes, M1 (inflammatory) and M2 (anti-inflammatory/healing), exert opposing effects on the repair of various tissues. In this study, a new strategy to promote tissue repair and tissue-to-biomaterial integration by M1-to-M2 macrophage transition using artificial apoptotic cell mimetics (phosphatidylserine liposomes; PSLs) was developed using bone as a model tissue. Titanium was also selected as a model substrate material because it is widely used for dental and orthopedic implants. Titanium implants were functionalized with multilayers via layer-by-layer assembly of cationic protamine and negatively charged PSLs that were chemically stabilized to prevent disruption of lipid bilayers. Samples carrying PSL multilayers could drive M1-type macrophages into M2-biased phenotypes, resulting in a dramatic change in macrophage secretion for tissue regeneration. In a rat femur implantation model, the PSL-multilayer-coated implant displayed augmented de novo bone formation and bone-to-implant integration, associated with an increased M1-to-M2-like phenotypic transition. This triggered the proper generation and activation of bone-forming osteoblasts and bone-resorbing osteoclasts relative to their uncoated counterparts. This study demonstrates the benefit of local M1-to-M2 macrophage polarization induced by PSL-multilayers constructed on implants for potent bone regeneration and bone-to-implant integration. The results of this study may help in the design of new immunomodulatory biomaterials. STATEMENT OF SIGNIFICANCE: Effective strategies for tissue regeneration are essential in the clinical practice. The macrophage phenotypes, M1 (inflammatory) and M2 (anti-inflammatory/healing), exert opposing effects on the repair of various tissues. Artificially produced phosphatidylserine-containing liposomes (PSLs) can induce M2 macrophage polarization by mimicking the inverted plasma membranes of apoptotic cells. This study demonstrates the advantages of local M1-to-M2 macrophage polarization induced by PSL-multilayers constructed on implants for effective bone regeneration and osseointegration (bone-to-implant integration). Mechanistically, M2 macrophages promote osteogenesis but inhibit osteoclastogenesis, and M1 macrophages vice versa. We believe that our study makes a significant contribution to the design of new immunomodulatory biomaterials for regenerative medicine because it is the first to validate the benefit of PSLs for tissue regeneration.

Long-Term Outcomes of Adjuvant Denosumab in Breast Cancer

BACKGROUND: Adjuvant aromatase inhibitors increase osteoporosis and fractures in patients with hormone receptor–positive breast cancer. We have previously reported outcomes of the ABCSG-18 (study 18 from the Austrian Breast & Colorectal Cancer Study Group) trial showing that adjuvant anti–receptor activator of nuclear factor-κB ligand denosumab treatment counteracts these adverse effects and may improve outcomes. We report here the final long-term outcomes. METHODS: ABCSG-18 is a prospective, double-blind, placebo-controlled, phase 3 trial in which 3425 postmenopausal patients with early hormone receptor–positive breast cancer receiving aromatase inhibitor therapy were randomly assigned in 58 trial centers to receive either denosumab 60 mg or placebo administered subcutaneously every 6 months. The primary end point was the time to first clinical fracture after randomization. Secondary disease outcome–related end points were disease-free survival (DFS), bone metastasis–free survival (BMFS), and overall survival (OS). RESULTS: For this final protocol-defined analysis, median follow-up is 8 years (interquartile range, 6 to 9.6 years). There were 309 versus 368 DFS events (hazard ratio, 0.83; 95% confidence interval [CI], 0.71 to 0.97) in the denosumab versus the placebo group, respectively, resulting in an absolute 9-year DFS benefit of 3.5 percentage points (79.4 vs. 75.9%). Adjuvant denosumab improved BMFS by 2.5 percentage points (88.9 vs. 86.4%; hazard ratio, 0.81; 95% CI, 0.65 to 1.00) and OS by 1.0 percentage point (90.9 vs. 89.9%; hazard ratio, 0.80; 95% CI, 0.64 to 1.01). No new toxicities for this dose of adjuvant denosumab were observed. CONCLUSIONS: DFS, BMFS, and OS continued to show benefit in this final long-term analysis of ABCSG-18. There were no new toxicities. (Funded by Amgen; ClinicalTrials.gov number, NCT00556374.)

Comparison of denosumab and oral bisphosphonates for the treatment of glucocorticoid-induced osteoporosis: a systematic review and meta-analysis

BACKGROUND

Both denosumab and bisphosphonates have been demonstrated effective for glucocorticoid-induced osteoporosis. However, evidence-based medicine is still lacking to prove the clinical results between denosumab and bisphosphonates. This meta-analysis aims to compare the efficacy and safety between denosumab and oral bisphosphonates for the treatment of glucocorticoid-induced osteoporosis through evidence-based medicine.

METHODS

MEDLINE, EMBASE, and the Cochrane library databases were searched up to June 2022 for randomized controlled trials that compared denosumab and oral bisphosphonates in the treatment of glucocorticoid-induced osteoporosis. The following outcomes were extracted for comparison: percentage change in bone mineral density from baseline at the lumbar spine, total hip, femoral neck, and ultra-distal radius; percentage change from baseline in serum concentration of bone turnover markers; and incidence of treatment-emergent adverse events.

RESULTS

Four randomized controlled trials involving 714 patients were included. The pooled results showed that denosumab was superior to bisphosphonates in improving bone mineral density in lumbar spine (mean difference (MD) 1.70; 95% confidence interval (CI) 1.11-2.30; P < 0.001) and ultra-distal radius (MD 0.87; 95% CI 0.29-1.45; P = 0.003), and in suppressing C-terminal telopeptide of type 1 collagen (MD -34.83; 95% CI -67.37--2.28; P = 0.04) and procollagen type 1 N-terminal propeptide (MD -14.29; 95% CI -23.65- -4.94; P = 0.003) at 12 months. No significant differences were found in percentage change in total hip or femoral neck bone mineral density at 12 months, or in the incidence of treatment-emergent adverse events or osteoporosis-related fracture.

CONCLUSIONS

Compared with bisphosphonates, denosumab is superior in improving bone mineral density in lumbar spine and ultra-distal radius for glucocorticoid-induced osteoporosis. Further studies are needed to prove the efficacy of denosumab.

Bone Metastasis of Breast Cancer: Molecular Mechanisms and Therapeutic Strategies

Bone metastasis is a common complication of many types of advanced cancer, including breast cancer. Bone metastasis may cause severe pain, fractures, and hypercalcemia, rendering clinical management challenging and substantially reducing the quality of life and overall survival (OS) time of breast cancer patients. Studies have revealed that bone metastasis is related to interactions between tumor cells and the bone microenvironment, and involves complex molecular biological mechanisms, including colonization, osteolytic destruction, and an immunosuppressive bone microenvironment. Agents inhibiting bone metastasis (such as bisphosphate and denosumab) alleviate bone destruction and improve the quality of life of breast cancer patients with bone metastasis. However, the prognosis of these patients remains poor, and the specific biological mechanism of bone metastasis is incompletely understood. Additional basic and clinical studies are urgently needed, to further explore the mechanism of bone metastasis and develop new therapeutic drugs. This review presents a summary of the molecular mechanisms and therapeutic strategies of bone metastasis of breast cancer, aiming to improve the quality of life and prognosis of breast cancer patients and provide a reference for future research directions.

Guanylyl Cyclase-B Dependent Bone Formation in Mice is Associated with Youth, Increased Osteoblasts, and Decreased Osteoclasts

C-type natriuretic peptide (CNP) activation of guanylyl cyclase-B (GC-B) catalyzes the synthesis of cGMP in chondrocytes and osteoblasts. Elevated cGMP stimulates long bone growth, and inactivating mutations in CNP or GC-B reduce cGMP, which causes dwarfism. GC-B^7E/7E mice that express a GC-B mutant that cannot be inactivated by dephosphorylation exhibit increased CNP-dependent GC-B activity, which increases bone length, as well as bone mass and strength. Importantly, how GC-B increases bone mass is not known. Here, we injected 12-week-old, wild type mice once daily for 28 days with or without BMN-111 (Vosoritide), a proteolytically resistant CNP analog. We found that BMN-111 treated mice had elevated levels of osteocalcin and collagen 1 C-terminal telopeptide (CTX) as well as increased osteoblasts and osteoclasts. In BMN-111 injected mice, tibial mRNAs for Rank ligand and osteoprotegrin were increased and decreased, respectively, whereas sclerostin mRNA was elevated 400-fold, consistent with increased osteoclast activity and decreased osteoblast activity. Mineral apposition rates and trabecular bone mass were not elevated in response to BMN-111. Because 9-week-old male GC-B^7E/7E mice have increased bone mass but do not exhibit increased mineral apposition rates, we examined 4-week-old male GC-B^7E/7E mice and found that these animals had increased serum osteocalcin, but not CTX. Importantly, tibias from these mice had 37% more osteoblasts, 26% fewer osteoclasts as well as 36% and 40% higher mineral apposition and bone formation rates, respectively. We conclude that GC-B-dependent bone formation is coupled to an early juvenile process that requires both increased osteoblasts and decreased osteoclasts.

Emerging trends and focus of giant cell tumor of bone research from 2001-2021: A visualization research

Giant cell tumor of bone is a highly invasive benign tumor with a high postoperative recurrence rate.

OBJECTIVE

This study aims to analyze the research hotspots and trends of global research on giant cell tumor of bone in the past 20 years, to provide a reference for relevant personnel in this field to carry out academic research.

METHODS

The literature related to giant cell tumor of bone from 2001 to 2021 was retrieved from the Web of Science. The bibliometrics research method and VOS Viewer were used to extract and analyze the keywords of the journal authors' research institutions, and the research status and development direction in the recent 20 years were visualized.

RESULTS

A total of 2063 articles were included. The number of global publications is increasing every year. The United States contributes the most to global research, with the most citations and the highest H-index. The journal Clinical Orthopaedics and Related Research published the most articles on this issue. "Denosumab" and "h3f3a" will get more attention and be the next popular hotspot in the future.

CONCLUSION

The study of giant cell tumor of bone is a hot spot of continuous development and has an important contribution to human health.

The Innate Immune Microenvironment in Metastatic Breast Cancer

The immune system plays a fundamental role in neoplastic disease. In the era of immunotherapy, the adaptive immune response has been in the spotlight whereas the role of innate immunity in cancer development and progression is less known. The tumor microenvironment influences the terminal differentiation of innate immune cells, which can explicate their pro-tumor or anti-tumor effect. Different cells are able to recognize and eliminate no self and tumor cells: macrophages, natural killer cells, monocytes, dendritic cells, and neutrophils are, together with the elements of the complement system, the principal players of innate immunity in cancer development and evolution. Metastatic breast cancer is a heterogeneous disease from the stromal, immune, and biological point of view and requires deepened exploration to understand different patient outcomes. In this review, we summarize the evidence about the role of innate immunity in breast cancer metastatic sites and the potential targets for optimizing the innate response as a novel treatment opportunity.

Tumor Microenvironment, Clinical Features, and Advances in Therapy for Bone Metastasis in Gastric Cancer

Gastric cancer (GC) is one of the most malignant neoplasms worldwide, accounting for about 770,000 deaths in 2020. The incidence of gastric cancer bone metastasis (GC-BM) is low, about 0.9–13.4%, and GC patients develop GC-BM because of a suitable bone microenvironment. Osteoblasts, osteoclasts, and tumor cells interact with each other, secreting cytokines such as PTHrP, RANK-L, IL-6, and other growth factors that disrupt the normal bone balance and promote tumor growth. The functions and numbers of immune cells in the bone microenvironment are continuously inhibited, resulting in bone balance disorder due to the cytokines released from destroyed bone and growing tumor cells. Patients with GC-BM are generally younger than 65 years old and they often present with a later stage of the disease, as well as more aggressive tumors. They usually have shorter overall survival (OS) because of the occurrence of skeletal-related events (SREs) and undetected bone destruction due to the untimely bone inspection. Current treatments of GC-BM focus mainly on gastric cancer and SRE-related treatment. This article reviews the clinical features, possible molecular pathogeneses, and the most commonly used diagnostic methods and treatments of bone metastasis in gastric cancer.

Beneficial effects of denosumab on muscle performance in patients with low BMD: a retrospective, propensity score-matched study

This study examined the effects of denosumab compared to bisphosphonates and vitamin D alone on muscle performance in patients with low BMD. While grip force improved in both the denosumab and bisphosphonate group, a superior increase in chair rising test force was observed in the denosumab group.

INTRODUCTION

The aim of this study was to investigate the effect of the anti-resorptive agent denosumab (Dmab) on upper and lower limb muscle performance compared to bisphosphonate (BP) treatment and vitamin D supplementation alone (i.e., basic therapy) in patients with low BMD.

METHODS

This retrospective, propensity score-matched (sex, age, BMI, follow-up time) cohort study included 150 osteopenic or osteoporotic patients receiving basic (n = 60), BP (n = 30) or Dmab (n = 60) therapy. All patients underwent a musculoskeletal assessment at baseline and follow-up, including DXA, laboratory bone metabolism parameters, grip force, and chair rising test mechanography. Mean annual percentage changes were calculated and compared between study groups.

RESULTS

After a mean follow-up period of 17.6 ± 9.0 months, a significantly higher increase in grip force in both the Dmab (p < 0.001) and BP group (p = 0.001) compared to the vitamin D group was observed (vitamin D =  - 6.1 ± 10.2%; BP =  + 0.8 ± 8.2%; Dmab =  + 5.1 ± 25.5%). The Dmab group showed a significantly higher increase in chair rising test force compared to the BP group (vitamin D =  + 5.8 ± 12.7%; BP =  + 0.9 ± 8.6%; Dmab =  + 8.2 ± 14.4%; Dmab vs. BP p = 0.03). Neither the changes in BMD nor in bone metabolic parameters were associated with changes in muscle performance.

CONCLUSION

Dmab resulted in increased muscle strength in the upper and lower limbs, indicating systemic rather than site-specific effects as compared to BP. Based on these findings, Dmab might be favored over other osteoporosis treatments in patients with low BMD and poor muscle strength.

Yaşlı yetişkinlerde osteoporoz tedavisinde antirezorptif ajanların karşılaştırılması

Purpose: There are few studies comparing the effectiveness of anti-osteoporotic drugs among elderly population. In this study, we aimed to compare the effectiveness of alendronate, zoledronic acid, and denosumab in older adults. Materials and Methods: A total of 350 older adults with osteoporosis, aged 65 and over were included in this retrospective study. The number of patients receiving alendronate, zoledronic acid, and denosumab was 111, 121, and 118, respectively. Bone mineral density (BMD) was measured at baseline and 24th month by performing dual-energy x-ray absorptiometry (DXA) scans. Results: The age, comorbidities, and laboratory analysis results of the patients were similar. While there was no statistically significant difference in BMD response at the femoral neck between the treatment groups (Baseline BMDs for alendronate, zoledronic acid, and denosumab were 0.61, 0.59, and 0.58, respectively, while 24th month BMDs were 0.62, 0.60, and 0.59, respectively), alendronate and zoledronic acid improved lumbar spine BMD more than denosumab (Baseline BMDs for alendronate, zoledronic acid, and denosumab were 0.74, 0.74, and 0.71, respectively, while 24th month BMDs were 0.77, 0.78, and 0.73). Conclusion: This study has shown that, like parenteral antiresorptive agents, alendronate can elicit a desirable BMD response in older osteoporotic adults. The results of our study may guide osteoporosis treatment in older individuals.

Molecular mechanisms, physiological roles, and therapeutic implications of ion fluxes in bone cells: Emphasis on the cation-Cl- cotransporters

Bone turnover diseases are exceptionally prevalent in human and come with a high burden on physical health. While these diseases are associated with a variety of risk factors and causes, they are all characterized by common denominators, that is, abnormalities in the function or number of osteoblasts, osteoclasts, and/or osteocytes. As such, much effort has been deployed in the recent years to understand the signaling mechanisms of bone cell proliferation and differentiation with the objectives of exploiting the intermediates involved as therapeutic preys. Ion transport systems at the external and in the intracellular membranes of osteoblasts and osteoclasts also play an important role in bone turnover by coordinating the movement of Ca²⁺ , PO₄ ^2- , and H⁺ ions in and out of the osseous matrix. Even if they sustain the terminal steps of osteoformation and osteoresorption, they have been the object of very little attention in the last several years. Members of the cation-Cl^- cotransporter (CCC) family are among the systems at work as they are expressed in bone cells, are known to affect the activity of Ca²⁺ -, PO₄ ^2- -, and H⁺ -dependent transport systems and have been linked to bone mass density variation in human. In this review, the roles played by the CCCs in bone remodeling will be discussed in light of recent developments and their potential relevance in the treatment of skeletal disorders.

A bibliometric research based on hotspots and frontier trends of denosumab

Denosumab is a monoclonal antibody that targets and inhibits the osteoclast activating factor receptor activator for nuclear factor-κB ligand (RANKL). It has been widely used in the treatment of osteoporosis, giant cell tumors of bone, and in the prevention of malignant skeletal-related events (SREs). We collected the research results and related MeSH terms of denosumab from 2011 to 2021 through the Web of Science and PubMed, respectively. The literature was visualized and analyzed by CiteSpace and bibliometric online analysis platforms. The MeSH terms were biclustered using the Bibliographic Co-Occurrence Analysis System (BICOMB) and graph clustering toolkit (gCLUTO). The results show that the number of denosumab-related annual publications had increased from 51 to 215, with the United States leading and Amgen Inc. being the most influential in the past 10 years. Articles published in the Journal of Bone and Mineral Research had the highest total citations. Three scholars from Shinshu University in Matsumoto, Yukio Nakamura, Takako Suzuki, and Hiroyuki Kato, joined the field relatively late but produced the most. The clinical comparison and combination of denosumab with other drugs in the treatment of osteoporosis was the most significant focus of research. Drug withdrawal rebound and management strategies have gained more attention and controversy recently. MeSH analysis revealed eight major categories of research hotspots. Among them, exploring the multiple roles of the RANK-RANKL-OPG system in tumor progression, metastasis, and other diseases is the potential direction of future mechanism research. It is a valuable surgical topic to optimize the perioperative drug administration strategy for internal spinal fixation and orthopedic prosthesis implantation. Taken together, the advantages of denosumab were broad and cost-effective. However, there were still problems such as osteonecrosis of the jaw, severe hypocalcemia, a high recurrence rate of giant cells in the treatment of bone and individual sarcoidosis, and atypical femoral fractures, which need to be adequately solved.

Identification of a binding site on soluble RANKL that can be targeted to inhibit soluble RANK-RANKL interactions and treat osteoporosis

One of the major challenges for discovering protein-protein interaction inhibitors is identifying selective and druggable binding sites at the protein surface. Here, we report an approach to identify a small molecular binding site to selectively inhibit the interaction of soluble RANKL and RANK for designing anti-osteoporosis drugs without undesirable immunosuppressive effects. Through molecular dynamic simulations, we discovered a binding site that allows a small molecule to selectively interrupt soluble RANKL-RANK interaction and without interfering with the membrane RANKL-RANK interaction. We describe a highly potent inhibitor, S3-15, and demonstrate its specificity to inhibit the soluble RANKL-RANK interaction with in vitro and in vivo studies. S3-15 exhibits anti-osteoporotic effects without causing immunosuppression. Through in silico and in vitro experiments we further confirm the binding model of S3-15 and soluble RANKL. This work might inspire structure-based drug discovery for targeting protein-protein interactions.

Where is bone science taking us?

Bone science has over the last decades unraveled many important pathways in bone and mineral metabolism and the interplay between genetic factors and the environment. Some of these discoveries have led to the development of pharmacological treatments of osteoporosis and rare bone diseases. Other scientific avenues have uncovered a role for the gut microbiome in regulating bone mass, which have led to investigations on the possible therapeutic role of probiotics in the prevention of osteoporosis. Huge advances have been made in identifying the genes that cause rare bone diseases, which in some cases have led to therapeutic interventions. Advances have also been made in understanding the genetic basis of the more common polygenic bone diseases, including osteoporosis and Paget's disease of bone (PDB). Polygenic profiles are used for establishing genetic risk scores aiming at early diagnosis and intervention, but also in Mendelian randomization (MR) studies to investigate both desired and undesired effects of targets for drug design.

Pharmacokinetics, pharmacodynamics, safety, and immunogenicity of a biosimilar of denosumab (LY06006): a randomized, double-blind, single-dose, parallel-controlled clinical study in healthy Chinese subjects

OBJECTIVES

To compare the pharmacokinetics (PK), pharmacodynamics (PD), safety, and immunogenicity of LY06006 (denosumab biosimilar) and denosumab (Prolia®) in healthy Chinese adult male subjects.

METHODS

In this randomized, double-blind, parallel-controlled, single-dose, comparative biosimilar study, A total of 168 subjects received 60 mg of LY06006 or denosumab by subcutaneous (SC) abdominal injections in a 1:1 ratio with a follow-up period of 168 days.

RESULTS

After a single SC abdominal injection of 60 mg LY06006/denosumab, the geometric mean ratio of the main pharmacokinetic parameters, C_max and AUC_0-∞, of the two drugs were 97.57% and 104.27%, respectively; the geometric mean ratio of the main pharmacodynamic parameters AUEC_0-t and E_max, were 101.00% and 99.64%, respectively, and the 90% confidence interval was observed to be within 80-125%. The subjects in the test group (LY06006) and control group (denosumab) were all negative for anti-drug antibody (ADA). The incidence and severity of treatment-emergent adverse events (TEAEs) and adverse reactions (ADR) were similar for both groups, and no grade 3 or higher TEAEs occurred in either group.

CONCLUSIONS

This study demonstrated that LY06006 and denosumab have similar characteristics and bioequivalence in pharmacokinetics. Moreover, they had similar pharmacodynamic profiles, safety, and immunogenicity.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT04973722.

Development of an Orally Active Small-Molecule Inhibitor of Receptor Activator of Nuclear Factor-κB Ligand

Receptor activator of nuclear factor-κB (RANK) and its ligand, RANKL, play pivotal roles in bone remodeling. The monoclonal antibody denosumab successfully inhibited the maturation of osteoclasts (OCs) by binding to RANKL in the clinic. We continued our efforts to develop small-molecule inhibitors of RANKL. In this work, 41 β-carboline derivatives were synthesized based on previously synthesized compound Y1599 to improve its drug-like properties. Compound Y1693 was identified as a potent RANKL inhibitor that improved absorption-distribution-metabolism-excretion properties and effectively prevented RANKL-induced osteoclastogenesis and bone resorption. Furthermore, Y1693 also suppressed the expression of OC marker genes. Moreover, Y1693 demonstrated good tolerability and efficacy in an orally administered mouse model of osteoporosis as well as the ability to rescue alveolar bone loss in vivo caused by periodontal disease. Collectively, the above findings may provide a valuable direction for the development of novel antiresorptive therapies that target RANKL.

Osteonecrosis of the Jaw Caused by Denosumab in Treatment-Naïve and Pre-Treatment with Zoledronic Acid Groups: A Time-to-Onset Study Using the Japanese Adverse Drug Event Report (JADER) Database

BACKGROUND

Medication-related osteonecrosis of the jaw is a serious adverse event associated with bone-modifying agents, such as injectable bisphosphonate (zoledronic acid) and the anti-receptor activator of nuclear factor-κB ligand antibody (denosumab).

OBJECTIVE

This study aims to evaluate and compare the time-to-onset profile for medication-related osteonecrosis of the jaw associated with denosumab between treatment-naïve (naïve group) and pre-treatment with zoledronic acid (post-zoledronic acid group) patients using the Japanese Adverse Drug Event Report database.

METHODS

Medication-related osteonecrosis of the jaw was defined according to the Medical Dictionary for Regulatory Activities. The medication-related osteonecrosis of the jaw onset profiles were evaluated using the Weibull shape parameter and the log-rank test.

RESULTS

The Japanese Adverse Drug Event Report database contains 632,409 reports published between April 2004 and March 2020. In the time-to-onset analysis, after extracting the combinations with complete information for the treatment start date and the medication-related osteonecrosis of the jaw onset date, 272 reports of the naïve group and 86 reports of the post-zoledronic acid group were analyzed. The median onset in the naïve and post-zoledronic acid groups was 487.0 (25-75%: 274.0-690.8) and 305.5 (25-75%: 158.3-508.5) days, respectively. Medication-related osteonecrosis of the jaw occurred earlier in the post-zoledronic acid group than in the naïve group, and the log-rank test demonstrated a significant difference in their time transitions (p < 0.0001).

CONCLUSIONS

The results indicated a risk of medication-related osteonecrosis of the jaw in naïve and post-zoledronic acid groups and a shorter onset time in the latter than in the former. Thus, healthcare professionals should take the early risk of medication-related osteonecrosis of the jaw into account when switching patients from zoledronic acid to denosumab treatment.

The 100 most cited papers on bone metastasis: A bibliometric analysis

•

Citations per article in the most 100 top cited articles ranged from 357 to 2167.

•

The leading country was USA, Canada, and United Kingdom.

•

Clinical management of bone metastasis from different malignancy origins.

•

Intense collaborative activity between countries and institutions was obvious between the selected papers.

Background

Over the past few decades, a vast number of articles focused on bone metastasis have been published. Bibliometric analysis is helpful to determine the qualities and characteristics and to reveal the influential articles in this field.

Methods

All the databases in Web of Science were utilized to identify articles published from 1961 to 2020. The top 100 most cited articles on bone metastases were involved for degree centrality analysis and analyses on publication time and citations, journals, authors, geographical distribution, research institutions, and research keywords.

Results

The selected articles were published mainly from 1986 to 2015. The 100 most cited articles were selected from a total of 67,451 citations out of 90,502 publications with a density of 50.239 citations/year. Citations per article ranged from 357 to 2167. The leading country was USA, followed by Canada and United Kingdom. The most frequently studied themes were clinical management of bone metastasis from different malignancy origins. A co-authorship analysis revealed an intense collaborative activity between countries and institutions.

Conclusions

This study identified the top 100 most cited articles on bone metastasis. Publication time, area, and theme distribution were thoroughly analyzed. The present study highlighted some of the most influential contributions to the field. Clinical and academic communities have shown a sustained interest in the management of bone metastasis.

Denosumab and Risk of Community-acquired Pneumonia: A Population-based Cohort Study

CONTEXT

Recent meta-analyses of randomized controlled trials have raised concerns that denosumab might increase the risk of infection. However, data of denosumab on the risk of community-acquired pneumonia are sparse.

OBJECTIVE

This work aimed to examine the risk of community-acquired pneumonia in individuals receiving denosumab compared to those receiving alendronate.

METHODS

We conducted a propensity score-matched cohort study with a UK primary care database (IQVIA Medical Research Database). We examined the relation of denosumab to community-acquired pneumonia using a Cox proportional hazard model. The study participants were osteoporotic patients older than 45 years who were initiators of denosumab or alendronate from August 1, 2010, to September 17, 2020. The outcome measure was community-acquired pneumonia.

RESULTS

Patients treated with denosumab (n = 933) were compared with those treated with alendronate (n = 4652). In the matched population, the mean (SD) age was 77 (11) years, 89% were women, and about half of the study population had a history of major osteoporotic fracture. Over 5 years of follow-up, the incidence of community-acquired pneumonia per 1000 person-years was 72.0 (95% CI, 60.1-85.7) in the denosumab group and 75.1 (95% CI, 69.4-81.2) in the alendronate group. The hazard of community-acquired pneumonia was similar between denosumab and alendronate users (hazard ratio [HR] 0.96; 95% CI, 0.79-1.16). The results remained consistent in a series of sensitivity analyses, with HR ranging from 0.82 (95% CI, 0.65-1.04) to 0.99 (95% CI, 0.81-1.21).

CONCLUSION

Denosumab does not significantly increase the susceptibility of community-acquired pneumonia and could possibly be safely used for the management of osteoporosis.

Exploring new pathways in endocrine-resistant breast cancer

The most common breast cancer (BC) subtypes are hormone-dependent, being either estrogen receptor-positive (ER⁺), progesterone receptor-positive (PR⁺), or both, and altogether comprise the luminal subtype. The mainstay of treatment for luminal BC is endocrine therapy (ET), which includes several agents that act either directly targeting ER action or suppressing estrogen production. Over the years, ET has proven efficacy in reducing mortality and improving clinical outcomes in metastatic and nonmetastatic BC. However, the development of ET resistance promotes cancer survival and progression and hinders the use of endocrine agents. Several mechanisms implicated in endocrine resistance have now been extensively studied. Based on the current clinical and pre-clinical data, the present article briefly reviews the well-established pathways of ET resistance and continues by focusing on the three most recently uncovered pathways, which may mediate resistance to ET, namely receptor activator of nuclear factor kappa B ligand (RANKL)/receptor activator of nuclear factor kappa B (RANK), nuclear factor kappa B (NFκB), and Notch. It additionally overviews the evidence underlying the approval of combined therapies to overcome ET resistance in BC, while highlighting the relevance of future studies focusing on putative mediators of ET resistance to uncover new therapeutic options for the disease.

Ganoderic acid A improves osteoarthritis by regulating RANKL/OPG ratio

Ganoderma mushrooms have been used to treat rheumatoid arthritis (RA) in East Asia. Whether Ganoderic acid A (GAA), the natural product extracted from Ganoderma, could be utilized to alleviate osteoarthritis (OA) is investigated in this study. Destabilization of the medial meniscus (DMM) model was constructed to reveal the in vivo effect of GAA. We found that GAA could significantly alleviate the pathology of DMM, as confirmed by the diminished maximum histologic scores. On the other hand, GAA could down-regulate the relative expression of osteoprotegerin (OPG) and up-regulate the relative expression of nuclear factor-kappa B ligand (RANKL) in DMM cartilage and human articular chondrocytes (HC-A) cells with diminished matrix metallopeptidase 13 (MMP-13) secretion in the synovial fluid. It was further demonstrated that the serum concentration of OPG was correlated with the severity of osteoarthritis. All these data reveal that GAA could improve OA by regulating the RANKL/OPG ratio to inhibit the secretion of MMP-13.

Progress in research of non-cirrhotic chronic viral hepatitis with osteoporosis

Osteoporosis is one of the complications of chronic viral hepatitis related cirrhosis, and the pathogenesis and treatment methods for osteoporosis have been extensively studied. However, whether chronic viral hepatitis is the risk factor for osteoporosis is still controversial. Some studies have demonstrated the relationship between them, but there is still no systematic judgment on its pathogenesis and treatment. In this review, we systematically summarize the risk, possible pathogenesis, and treatment scheme of osteoporosis secondary to non-cirrhosis chronic viral hepatitis, with an aim to clarify the relationship between chronic viral hepatitis and osteoporosis, remind clinicians to be alert to the possibility of osteoporosis complicated by chronic viral hepatitis, and provide support for clinical diagnosis and treatment.

RANKL biology

Since the receptor activator of nuclear factor-kappa B ligand (RANKL), its cognate receptor activator of nuclear factor-kappa B (RANK), and the decoy receptor osteoprotegerin (OPG) were discovered, a number of studies have uncovered the crucial role of the RANKL-RANK-OPG pathway in controlling the key aspect of bone homeostasis, the immune system, inflammation, cancer, and other systems under pathophysiological condition. These findings have expanded the understanding of the multifunctional biology of the RANKL-RANK-OPG pathway and led to the development of therapeutic potential targeting this pathway. The successful development and application of anti-RANKL antibody in treating diseases causing bone loss validates the utility of therapeutic approaches based on the modulation of this pathway. Moreover, recent studies have demonstrated the involvement of the RANKL-RANK pathway in osteoblast differentiation and bone formation, shedding light on the RANKL-RANK dual signaling in coupling bone resorption and bone formation. In this review, we will summarize the current understanding of the RANKL-RANK-OPG system in the context of the bone and the immune system as well as the impact of this pathway in disease conditions, including cancer development and metastasis.

The Roles of RANK/RANKL/OPG in Cardiac, Skeletal, and Smooth Muscles in Health and Disease

Although their physiology and functions are very different, bones, skeletal and smooth muscles, as well as the heart have the same embryonic origin. Skeletal muscles and bones interact with each other to enable breathing, kinesis, and the maintenance of posture. Often, muscle and bone tissues degenerate synchronously under various conditions such as cancers, space travel, aging, prolonged bed rest, and neuromuscular diseases. In addition, bone tissue, skeletal and smooth muscles, and the heart share common signaling pathways. The RANK/RANKL/OPG pathway, which is essential for bone homeostasis, is also implicated in various physiological processes such as sarcopenia, atherosclerosis, and cardiovascular diseases. Several studies have reported bone-skeletal muscle crosstalk through the RANK/RANKL/OPG pathway. This review will summarize the current evidence indicating that the RANK/RANKL/OPG pathway is involved in muscle function. First, we will briefly discuss the role this pathway plays in bone homeostasis. Then, we will present results from various sources indicating that it plays a physiopathological role in skeletal, smooth muscle, and cardiac functions. Understanding how the RANK/RANKL/OPG pathway interferes in several physiological disorders may lead to new therapeutic approaches aimed at protecting bones and other tissues with a single treatment.

Pharmacological Therapies for the Management of Inflammatory Bone Resorption in Periodontal Disease: A Review of Preclinical Studies

Periodontitis, a highly prevalent multicausal chronic inflammatory and destructive disease, develops as a result of complex host-parasite interactions. Dysbiotic bacterial biofilm in contact with the gingival tissues initiates a cascade of inflammatory events, mediated and modulated by the host's immune response, which is characterized by increased expression of several inflammatory mediators such as cytokines and chemokines in the connective tissue. If periodontal disease (PD) is left untreated, it results in the destruction of the supporting tissues around the teeth, including periodontal ligament, cementum, and alveolar bone, which lead to a wide range of disabilities and poor quality of life, thus imposing significant burdens. This process depends on the differentiation and activity of osteoclasts, the cells responsible for reabsorbing the bone tissue. Therefore, the inhibition of differentiation or activity of these cells is a promising strategy for controlling bone resorption. Several pharmacological drugs that target osteoclasts and inflammatory cells with immunomodulatory and anti-inflammatory effects, such as bisphosphonates, anti-RANK-L antibody, strontium ranelate, cathepsin inhibitors, curcumin, flavonoids, specialized proresolving mediators, and probiotics, were already described to manage inflammatory bone resorption during experimental PD progression in preclinical studies. Meantime, a growing number of studies have described the beneficial effects of herbal products in inhibiting bone resorption in experimental PD. Therefore, this review summarizes the role of several pharmacological drugs used for PD prevention and treatment and highlights the targeted action of all those drugs with antiresorptive properties. In addition, our review provides a timely and critical appraisal for the scientific rationale use of the antiresorptive and immunomodulatory medications in preclinical studies, which will help to understand the basis for its clinical application.

American Association of Oral and Maxillofacial Surgeons' Position Paper on Medication-Related Osteonecrosis of the Jaws-2022 Update

Strategies for management of patients with, or at risk for, medication-related osteonecrosis of the jaws (MRONJ) - formerly referred to as bisphosphonate-related osteonecrosis of the jaws (BRONJ)-were set forth in the American Association of Oral and Maxillofacial Surgeons (AAOMS) position papers in 2007, 2009 and 2014. The position papers were developed by a committee appointed by the AAOMS Board of Trustees and comprising clinicians with extensive experience in caring for these patients, as well as clinical and basic science researchers. The knowledge base and experience in addressing MRONJ continues to evolve and expand, necessitating modifications and refinements to the previous position papers. Three members of the AAOMS Committee on Oral, Head, and Neck Oncologic and Reconstructive Surgery (COHNORS) and three authors of the 2014 position paper were appointed to serve as a working group to analyze the current literature and revise the guidance as indicated to reflect current knowledge in this field. This update contains revisions to diagnosis and management strategies and highlights the current research status. AAOMS maintains that it is vitally important for this information to be disseminated to other relevant healthcare professionals and organizations.

Bone Mineral and Organic Properties in Postmenopausal Women Treated With Denosumab for Up to 10 years

In postmenopausal women with osteoporosis, denosumab (DMAb) therapy through 10 years resulted in significantly higher degree of mineralization of bone, with a subsequent increase from years 2-3 to year 5 and no further difference between years 5 and 10. Our aim was to assess the variables reflecting the quality of bone mineral and organic matrix (Fourier transform infrared microspectroscopy), and the microhardness of bone (Vickers microindentation). Cross-sectional assessments were performed in blinded fashion on iliac bone biopsies from osteoporotic women (72 from FREEDOM trial, 49 from FREEDOM Extension trial), separately in cortical and cancellous compartments. After 2-3 years of DMAb, mineral/matrix ratio and microhardness of cortical bone were significantly higher compared with placebo, whereas mineral maturity, mineral crystallinity, mineral carbonation, and collagen maturity were not different in both bone compartments. Through 5 years of DMAb, mineral carbonation was significantly lower and mineral/matrix ratio, mineral maturity, and crystallinity were significantly higher versus 2-3 years and were not different between 5 and 10 years, with the exception of mineral maturity in cancellous bone. These data support a transition of mineral to more mature crystals (within physiological range) and the completeness of secondary mineralization within 5 years of DMAb treatment. Microhardness in cortical and cancellous compartments was significantly lower at 5 years of DMAb versus 2-3 years and was not different from years 5 to 10. The lower microhardness at years 5 and 10 is likely the result of maturation of the organic matrix in a persistently low state of bone remodeling over 5 and 10 years. © 2022 American Society for Bone and Mineral Research (ASBMR).

Bone Metastases: From Mechanisms to Treatment

OBJECTIVES

Bone metastases are of high clinical relevance because they are a frequent complication of most types of common cancers, such as breast and prostate. The metastatic process is complex, requiring the completion of several different steps to allow successful dissemination and homing. In addition, preparation of the metastatic niche changes the constant cycle of bone matrix formation and degradation, leading to the clinical phenotypes of lytic and sclerotic lesions. We review our current knowledge on this topic and briefly explain the current treatment landscape of bone metastasis.

DATA SOURCES

These include PubMed, international guidelines, and clinician experience.

CONCLUSION

Bone metastases remain a clinical challenge that negatively impacts patients prognosis and quality of life. A comprehensive understanding of the complex molecular mechanisms that results in bone metastasis is the basis for successful treatment of affected patients. The disruption of bone matrix metabolism is already recognized as the prerequisite for metastasis formation, but many open questions remain that need to be addressed in future research to establish individually tailored treatment approaches.

IMPLICATIONS FOR NURSING PRACTICE

Patient-centered therapy of bone metastases requires suitable pharmacological options, and importantly a holistic approach in care delivery across the multidisciplinary team. Nurses provide the cornerstone of the multidisciplinary team and provide the closest and the most frequent contact to the patient and their families to provide timely intervention. Nurses require a basic understanding of the complex physiology of metastasis to inform practice.