osteoprotegerin-deficient mice develop early onset osteoporosis and arterial calcification

Chronically increased osteoclastogenesis in adult celiac disease patients does not hinder improvement in bone health induced by gluten-free diet: Role of vitamin D, OPG and IL-6

The etiology of bone loss in celiac disease (CeD) remains a clinical challenge, with uncertainties present such as the extent of involvement of malabsorption and inflammation-induced osteoresorption processes in development of osteopenia/osteoporosis (OPN/OP), or reasons for failure to achieve healthy bone mass (BMD) even after long-term gluten-free diet (GFD) treatment. This observational prospective study explores the in vitro osteoclastogenic potential of peripheral blood precursors originating from adult active (newly diagnosed and untreated) celiac disease patients (aCeD) and describes the longitudinal changes in osteoclastogenesis after long-term adherence to GFD. To find connections between in vitro observations and in vivo bone metabolism changes, serum levels of 25(OH)D3, PTH, bCTX, PINP, CRP, IL-6, RANKL and OPG were measured before and after GFD and levels of these markers were correlated with the rate of osteoclastogenesis in vitro. OPG and IL-6 showed associations with BMD and/or presence of OPN/OP. Patients after GFD (CeD-GFD) exhibited improved BMD and increased serum 25(OH)D3 levels, alongside reduced bCTX and PINP levels. Compared to healthy donors, aCeD osteoclast genesis in vitro was higher and, surprisingly, remained elevated even in CeD-GFD patients. Negative correlation was found between osteoclastogenesis rate and serum OPG in aCeD, while osteoclastogenesis rate positively correlated with PTH in CeD-GFD. These results highlight OPG as marker for risk of OPN/OP in CeD and suggest that improvement of BMD after GFD is a result of uncoupling between bone metabolism and osteoresorptive action of osteoclasts after GFD.

Long-Term Denosumab Treatment in Adults with Juvenile Paget Disease

Juvenile Paget disease (JPD) is a very rare disease, mainly caused by biallelic inactivating mutations in the TNFRSF11B gene that encodes osteoprotegerin. Owing to its rarity, the treatment of JPD is largely empirical. Accelerated bone turnover as assessed by biochemical markers, such as alkaline phosphatase (ALP), can be suppressed by bisphosphonate treatment, but it relapses if bisphosphonate treatment is discontinued. In this report, we describe our experience with long-term denosumab treatment in two adults with JPD, homozygous for the "Balkan" mutation (966_969delTGACinsCTT) in TNFRSF11B. Subject 1 started denosumab in age 35 and subject 2 in age 34. Both continue treatment until today, for 13.5 and 12 years, respectively. ALP was steadily normalized in both. Bone pain decreased and mobility improved. Hearing did not further deteriorate and no new fracture occurred. Vision remained unchanged in subject 2, but subject 1 experienced sudden vision loss of the right eye at age 46, which was successfully managed with intravitreal treatment with anti-vascular endothelial growth factor medications. In conclusion, long-term denosumab administration in adults with JPD, who had been previously treated with bisphosphonates, was safe and effective in terms of the skeletal disease, but it may not prevent the emergence of retinopathy.

ERK inhibits osteoclast differentiation in RAW 264.7 cells through the osteoprotegerin-mediated autophagy

Osteoclasts (OCs) are bone-resorbing cells derived from the monocyte/macrophage lineage. The extracellular signal-regulated kinase (ERK) pathway controls cellular responses such as proliferation, differentiation, and survival, including those of OCs. In the present study, ERK inhibitors reduced the proliferation of bone marrow-derived macrophages (BMMs) and RAW 264.7 cells. However, ERK inhibitors decreased OC differentiation in BMMs but increased it in RAW 264.7 cells. ERK downregulation using small interfering RNA transfection also increased the OC differentiation and the expression of receptor activator of nuclear factor-κB, OC-specific markers, and OC-associated transcription factors in RAW 264.7 cells. These findings suggest ERK regulates OC differentiation in RAW 264.7 cells differently than in BMMs. Thus, we further investigated the mechanism by which ERK negatively regulates OC differentiation in RAW 264.7 cells. ERK inhibition decreased the expression of osteoprotegerin (OPG), a negative regulator of OC differentiation. OPG knockdown increased OC formation. ERK inhibitors activated the Akt/mammalian target of the rapamycin (mTOR) signaling pathway while inhibiting unc-51-like autophagy activating kinase 1 (ULK1). This resulted in decreased levels of microtubule-associated protein 1A/1B-light chain 3-II (LC3-II) and increased levels of p62, thereby reducing autophagy. In addition, OPG knockdown reduced autophagy by activating Akt/mTOR and inhibiting ULK1, resulting in decreased LC3-II and accumulated p62. Therefore, ERK inhibition promoted OC differentiation by downregulating OPG-mediated inhibition of osteoclastogenesis and autophagy in RAW 264.7 cells. These findings highlight ERK's complex role in OC differentiation and suggest that understanding ERK's dual impact on OC differentiation can provide insights into novel treatment strategies for bone-related disorders.

From death to birth: how osteocyte death promotes osteoclast formation

Bone remodeling is a dynamic and continuous process involving three components: bone formation mediated by osteoblasts, bone resorption mediated by osteoclasts, and bone formation-resorption balancing regulated by osteocytes. Excessive osteocyte death is found in various bone diseases, such as postmenopausal osteoporosis (PMOP), and osteoclasts are found increased and activated at osteocyte death sites. Currently, apart from apoptosis and necrosis as previously established, more forms of cell death are reported, including necroptosis, ferroptosis and pyroptosis. These forms of cell death play important role in the development of inflammatory diseases and bone diseases. Increasing studies have revealed that various forms of osteocyte death promote osteoclast formation via different mechanism, including actively secreting pro-inflammatory and pro-osteoclastogenic cytokines, such as tumor necrosis factor alpha (TNF-α) and receptor activator of nuclear factor-kappa B ligand (RANKL), or passively releasing pro-inflammatory damage associated molecule patterns (DAMPs), such as high mobility group box 1 (HMGB1). This review summarizes the established and potential mechanisms by which various forms of osteocyte death regulate osteoclast formation, aiming to provide better understanding of bone disease development and therapeutic target.

Computed tomography provides a "one-stop-shop" targeted analysis for coronary artery calcification and osteoporosis: a review

The global trend towards longer lifespans has led to an aging population and a rise in the prevalence of diseases that predominantly affect elderly people. Coronary artery calcification (CAC) and osteoporosis (OP) are common in elderly populations. CT scans provide a reliable method to assess and monitor the progression of these diseases. In this review, the relationship between OP and CAC in terms of pathophysiological mechanism, comorbidity risk factors and clinical manifestations is reviewed, with a focus on the advancements in CT imaging, clinical applications and the possibility for "one-stop-shop" for examination.

Rapid and relaying deleterious effects of a gastrointestinal pathogen, Citrobacter rodentium, on bone, an extra-intestinal organ

Enteropathogenic infections cause pathophysiological changes in the host but their effects beyond the gastrointestinal tract are undefined. Here, using Citrobacter rodentium infection in mouse, which mimics human diarrheal enteropathogenic Escherichia coli, we show that gastrointestinal infection negatively affects bone remodeling, leading to compromised bone architecture. Transmission of infection through fecal-oral route from Citrobacter rodentium-infected to non-infected mice caused bone loss in non-infected cage mates. Mice with B cell deficiency (Igh6-/- mice) failed to clear C. rodentium infection and exhibited more severe and long-term bone loss compared to WT mice. Unbiased cytokine profiling showed an increase in circulating tumor necrosis factor α (TNFα) levels following Citrobacter rodentium infection, and immunoneutralization of TNFα prevented infection-induced bone loss completely in WT and immunocompromised mice. These findings reveal rapid, relaying, and modifiable effects of enteropathogenic infections on an extraintestinal organ-bone, and provide insights into the mechanism(s) through which these infections affect extraintestinal organ homeostasis.

Bone mineral density and the risk of kidney disease in patients with type 1 diabetes

AIM

To explore the association between bone disorder and the risk for progression of diabetic kidney disease (DKD) in persons with type 1 diabetes mellitus (T1DM).

METHODS

In this prospective cohort study the association between bone mineral density (BMD), bone-derived factors (sclerostin, Dickkopf-1, and osteoprotegerin (OPG)), and four outcomes were investigated: 1) progression of albuminuria; 2) decline in estimated glomerular filtration rate (eGFR) ≥30 %; 3) kidney failure (KF); and 4) a composite kidney outcome consisting of at least one of the outcomes.

RESULTS

In 318 participants (median follow-up time 5.5 years) patients with osteoporosis (BMD with T-score < -2.5) had increased risk of eGFR decline: hazard ratio (HR) 2.56 (95 % CI 1.06-6.19, p = 0.04), KF: HR 9.92 (95 % CI 1.16-84.95, p = 0.04), and the composite kidney outcome: HR 2.42 (95 % CI 1.18-4.96, p = 0.02). Patients with high OPG had increased risk of eGFR decline, KF, and the composite outcome, compared to patients with low OPG in unadjusted analysis. No bone-derived factor was associated with any outcome in adjusted analyses.

CONCLUSIONS

In patients with T1DM low BMD was associated with progression of DKD, suggesting an interaction between bone and kidney.

Osteoprotegerin, Osteopontin, and Osteocalcin Are Associated With Cardiovascular Events in Type 2 Diabetes: Insights From EXSCEL

OBJECTIVE

To evaluate the association of four bone metabolism biomarkers (osteoprotegerin, osteopontin, sclerostin, and osteocalcin) with cardiovascular events in people with type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

The Exenatide Study of Cardiovascular Event Lowering (EXSCEL) was a randomized clinical trial evaluating the cardiovascular (CV) safety and efficacy of once-weekly exenatide for patients with T2D. Candidate biomarker data were selected from proteomic profiling performed at baseline and 12 months after randomization samples by SomaScan assay in 5,473 trial participants. The primary composite outcome was the first occurrence of CV death, nonfatal myocardial infarction, or nonfatal stroke (major cardiovascular events [MACE]). Cox proportional hazards models controlling for confounders were used for time-to-event analyses to calculate hazard ratios (HRs) with 95% CI for a 1 SD increase in the biomarker concentrations.

RESULTS

The primary outcome occurred in 813 participants (14.9%). Higher levels of osteoprotegerin (HR 1.11; 95% CI 1.03-1.20; P = 0.0047) and osteopontin (HR 1.10; 95% CI 1.02-1.18; P = 0.0095) were associated with an increased risk of MACE. The addition of osteoprotegerin and osteopontin to a clinical predictive model containing traditional CV risk factors provided minimal incremental value for MACE prediction (C-index 0.629 vs. 0.638; likelihood ratio test P < 0.001). Osteocalcin and sclerostin were not associated with MACE. Osteocalcin had a nonlinear association with all-cause death and with CV death.

CONCLUSIONS

Higher levels of osteoprotegerin and osteopontin are associated with an increased risk of CV events in people with T2D, supporting the hypothesis that pathways involved in bone metabolism play a role in CV disease.

Genes involved in osteogenic differentiation induced by low‑intensity pulsed ultrasound in goldfish scales

The teleost scale is a unique calcified tissue that contains osteoclasts, osteoblasts, osteocytes and the bone matrix, similar to mammalian bone. Here, the effects of low-intensity pulsed ultrasound (LIPUS) on osteoblasts and osteoclasts in goldfish scales were investigated. Scales were treated with LIPUS, which is equivalent to use under clinical conditions (30 mW/cm2 for 20 min), then cultured at 15˚C. Alkaline phosphatase activity, a marker of osteoblasts, or tartrate-resistant acid phosphatase (TRAP) activity, a marker of osteoclasts was measured. The gene expression profile was examined using RNA-sequencing. Gene network and biological function analyses were performed using the Ingenuity® Pathways Knowledge Base. A single exposure of LIPUS significantly increased ALP activity but did not affect TRAP activity. These data indicated that LIPUS induced osteoblastic activation in goldfish scales. Using RNA-sequencing, numerous genes that were significantly and differentially expressed 3, 6, and 24 h after LIPUS exposure were observed. Ingenuity® pathway analysis demonstrated that three gene networks, GN-3h, GN-6h, and GN-24h, were obtained from upregulated genes at 3, 6 and 24 h culture, respectively, and included several genes associated with osteoblast differentiation, such as protein kinase D1, prostaglandin-endoperoxide synthase 2, TNFRSF11B (tumor necrosis factor receptor superfamily, member 11b) and WNT3A (Wnt family member 3A). A significant upregulation of expression levels of these genes in scales treated with LIPUS was confirmed by reverse transcription-quantitative polymerase chain reaction. These results contribute to elucidating the molecular mechanisms of osteoblast activation induced by LIPUS.

Osteoprotegerin as an Emerging Biomarker of Carotid Artery Stenosis? A Scoping Review with Meta-Analysis

Objective: In developed countries, stroke is the fifth cause of death, with a high mortality rate, and with recovery to normal neurological function in one-third of survivors. Atherosclerotic occlusive disease of the extracranial part of the internal carotid artery and related embolic complications are common preventable causes of ischemic stroke (IS), attributable to 7-18% of all first-time cases. Osteoprotegerin (OPG), a soluble member of the tumor necrosis factor receptor (TNFR) superfamily, is considered a modulator of vascular calcification linked to vascular smooth muscle cell proliferation and collagen production in atherosclerotic plaques. Therefore, OPG emerges as a potential biomarker (BM) of calcified carotid plaques and carotid artery stenosis (CAS). Methods: We performed a literature search of PubMed on OPG in CAS and atherosclerosis published until 2024. Results: Increased levels of serum OPG were reported in both patients with symptomatic and asymptomatic CAS, and higher values were observed in those with unstable atherosclerotic plaques. Notably, increased OPG levels were observed regardless of the location of atherosclerosis, including coronary and other peripheral arteries. In addition, chronic kidney disease, the most significant confounder disturbing the association between vascular damage and circulating OPG levels, decreases the usefulness of OPG as a BM in CAS. Conclusions: Osteoprotegerin may be considered an emerging BM of global rather than cerebrovascular atherosclerosis. Its diagnostic significance in identifying patients with asymptomatic CAS and their monitoring is limited.

Effect of Luteolin on cadmium-inhibited bone growth via suppressing osteoclastogenesis in laying chickens

Luteolin (Lut) is a flavonoid derived from several plant sources. Cadmium (Cd) is a widespread environmental contaminant and potential toxin with detrimental effects on animal health. However, the effect of Lut on Cd-induced inhibition of bone growth in laying chickens remains unclear. This study investigates the effects of Lut on Cd-induced inhibition of bone growth in the femur and tibia of laying chickens. A total of sixty 1-d-old green-eggshell yellow feather laying chickens were randomly assigned to 4 groups after a 5-d acclimation period: basal diet (Con), cadmium chloride (CdCl2, Cd), Lut, and Lut + Cd. Bone microstructure, serum biomarkers of bone remodeling, the levels of Cd, calcium (Ca), phosphorus (P), and trace metal elements were assessed using the micro-computed tomography (Micro-CT), enzyme-linked immunosorbent assay (ELISA), and microwave digestion, respectively. Bone remodeling biomarkers, late endosomal/lysosomal adaptor and MAPK and mTOR activator 1 (LAMTOR1), as well as the phosphorylation of AMP-activated protein kinase α (AMPKα) and protein kinase B (Akt), were quantified using the qRT-PCR and western blot. The results indicated that Lut effectively mitigated Cd-induced bone mass loss compared to the Cd group, resulting in increased bone volume (BV), bone surface/BV (BS/BV), connectivity density (Conn.Dn), and the length and weight of the femur and tibia in laying chickens. Mechanistically, compared to the Cd group, Lut restored the ratio of osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL) in serum and bone tissue, enhanced the expression of bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), osteocalcin (OCN), and Osterix (OSX), while reducing the levels of Ca, Cd, and alkaline phosphatase (ALP) activity, as well as the expression of osteopontin (OPN), c-Fos, osteoclast stimulatory-transmembrane protein (OC-STAMP), tartrate-resistant acid phosphatase, cathepsin K (CTSK), matrix metalloprotein-9 (MMP-9), LAMTOR1, and the phosphorylation of AMPKα and Akt. Therefore, Lut alleviates Cd-induced damage to the femur and tibia of chickens by promoting osteogenesis and inhibiting osteoclastogenesis, positioning Lut as a potential therapeutic plant extract for enhancing bone growth in laying chickens.

RANK/RANKL Signaling Pathway in Breast Development and Cancer

RANK pathway has attracted increasing interest as a promising target in breast cancer, given the availability of denosumab, an anti-RANKL drug. RANK signaling mediates progesterone-driven regulation of mammary gland development and favors breast cancer initiation by controlling mammary cell proliferation and stem cell fate. RANK activation promotes luminal mammary epithelial cell senescence, acting as an initial barrier to tumorigenesis but ultimately facilitating tumor progression and metastasis. Comprehensive analyses have demonstrated that RANK protein expression is an independent biomarker of poor prognosis in postmenopausal and estrogen receptor-negative breast cancer patients. RANK pathway also has multiple roles in immunity and inflammation, regulating innate and adaptive responses. In the tumor microenvironment, RANK and RANKL are expressed by different immune cell populations and contribute to the regulation of tumor immune surveillance, mainly driving immunosuppressive effects.Herein, we discuss the preventive and therapeutic potential of targeting RANK signaling in breast cancer given its tumor cell intrinsic and extrinsic effects. RANKL inhibition has been shown to induce mammary tumor cell differentiation and an antitumor immune response. Moreover, loss of RANK signaling increases sensitivity of breast cancer cells to chemotherapy, targeted therapies such as HER2 and CDK4/6 inhibitors, and immunotherapy. Finally, we describe clinical trials of denosumab for breast cancer prevention, such as those ongoing in women with high risk of developing breast cancer, large phase III clinical trials where the impact of adjuvant denosumab on disease-free survival has been assessed, and window trials to evaluate the immunomodulatory effects of denosumab in breast cancer and other solid tumors.

Interplay between bone marrow adiposity and bone resorption in RANKL-mediated modelled osteoporosis

Bone marrow adipose tissue (BMAT) accrues in osteoporosis, whereas its contribution to the progression of bone resorption remains insufficiently understood. To understand the mechanisms that promote BMAT expansion in osteoporosis, in the present study, we performed extensive analysis of the spatiotemporal pattern of BMAT expansion during the progression of bone resorption in TgRANKL transgenic mouse models of osteoporosis expressing human RANKL (receptor activator of nuclear factor-κB ligand). Our results showed that TgRANKL mice of both sexes developed dramatically increased BMAT expansion compared to wild-type (WT) littermates, that was analogous to the levels of RANKL expression and the severity of the bone loss phenotype. BMAT was formed at close proximity to areas undergoing active bone remodelling and bone resorption, whereas bone resorption preceded BMAT development. Expression analysis in bone fractions demonstrated that BMAT constitutes a major source for RANKL production. Ex vivo analysis of isolated bone marrow stromal cells from TgRANKL mice showed an increased adipogenic differentiation capacity compared to WT, while osteoclast supernatants further exaggerated adipogenesis, supporting a critical role of the osteoclast-derived secretome in the differentiation of bone marrow adipocytes. Furthermore, the effectiveness of an antiosteoporosis treatment in BMAT development was investigated upon treatment of TgRANKL models with the bisphosphonate alendronate. Notably, alendronate effectively improved bone mass and attenuated BMAT expansion, indicating a possible involvement of osteoclasts and bone resorption in BMAT development. On the contrary, inhibition of BMAT with PPARγ antagonists (GW9662 or BADGE) effectively ameliorated BMAT expansion but failed to reverse the osteoporotic phenotype of TgRANKL mice. Overall, our data demonstrate that TgRANKL mice constitute unique genetic mouse models for investigating the pathogenic mechanisms that regulate the development and expansion of BMAT in osteolytic diseases.

Abnormally accumulated GM2 ganglioside contributes to skeletal deformity in Tay-Sachs mice

Tay-Sachs Disease is a rare lysosomal storage disorder caused by mutations in the HEXA gene, responsible for the degradation of ganglioside GM2. In addition to progressive neurodegeneration, Tay-Sachs patients display bone anomalies, including kyphosis. Tay-Sachs disease mouse model (Hexa-/-Neu3-/-) shows both neuropathological and clinical abnormalities of the infantile-onset disease phenotype. In this study, we investigated the effects of GM2 accumulation on bone remodeling activity. Here, we evaluated the bone phenotype of 5-month-old Hexa-/-Neu3-/- mice with age-matched control groups using gene expression analysis, bone plasma biomarker analysis, and micro-computed tomography. We demonstrated lower plasma alkaline phosphatase activity and calcium levels with increased tartrate-resistant acid phosphatase levels, indicating reduced bone remodeling activity in mice. Consistently, gene expression analysis confirmed osteoblast reduction and osteoclast induction in the femur of mice. Micro-computed tomography and analysis show reduced trabecular bone volume, mineral density, number, and thickness in Hexa-/-Neu3-/- mice. In conclusion, we demonstrated that abnormal GM2 ganglioside accumulation significantly triggers skeletal abnormality in Tay-Sachs mice. We suggest that further investigation of the molecular basis of bone structure anomalies is necessary to elucidate new therapeutic targets that prevent the progression of bone symptoms and improve the life standards of Tay-Sachs patients. KEY MESSAGES: We detected the markers of bone loss-associated disorders such as osteopenia and osteoporosis in the Tay-Sachs disease mice model Hexa-/-Neu3-/-. We also demonstrated for the first time there is an increase in trabecular spacing and a reduction in trabecular thickness and number indicating skeletal abnormalities in mice model using micro-CT analysis.

Ligustrazine alleviates the progression of coronary artery calcification by inhibiting caspase-3/GSDME mediated pyroptosis

Coronary artery calcification (CAC) is an early marker for atherosclerosis and is mainly induced by the osteoblast-like phenotype conversion of vascular smooth muscle cells (VSMCs). Recent reports indicate that NOD-like receptor protein 3 (NLRP3)-mediated pyroptosis plays a significant role in the calcification of vascular smooth muscle cells (VSMCs), making it a promising target for treating calcific aortic valve disease (CAC). Ligustrazine, or tetramethylpyrazine (TMP), has been found effective in various cardiovascular and cerebrovascular diseases and is suggested to inhibit NLRP3-mediated pyroptosis. However, the function of TMP in CAC is unknown. Herein, influences of TMP on β-glycerophosphate (β-GP)-stimulated VSMCs and OPG-/- mice were explored. Mouse Aortic Vascular Smooth Muscle (MOVAS-1) cells were stimulated by β-GP with si- caspase-3, si- Gasdermin E (GSDME) or TMP. Increased calcification, reactive oxygen species (ROS) level, Interleukin-1beta (IL-1β) and Interleukin-18 (IL-18) levels, lactate dehydrogenase (LDH) release, enhanced apoptosis, and activated cysteine-aspartic acid protease-3 (caspase-3)/GSDME signaling were observed in β-GP-stimulated MOVAS-1 cells, which was sharply alleviated by si-caspase-3, si-GSDME or TMP. Furthermore, the impact of TMP on the β-GP-induced calcification and injury in MOVAS-1 cells was abolished by raptinal, an activator of caspase-3. Subsequently, OPG-/- mice were dosed with TMP or TMP combined with raptinal. Calcium deposition, increased nodules, elevated IL-1β and IL-18 levels, upregulated CASP3 and actin alpha 2, smooth muscle (ACTA2), and activated caspase-3/GSDME signaling in OPG-/- mice were markedly alleviated by TMP, which were notably reversed by the co-administration of raptinal. Collectively, TMP mitigated CAC by inhibiting caspase-3/GSDME mediated pyroptosis.

The role and mechanism of protein post‑translational modification in vascular calcification (Review)

Vascular calcification is closely associated with morbidity and mortality in patients with chronic kidney disease, atherosclerosis and diabetes. In the past few decades, vascular calcification has been studied extensively and the findings have shown that the mechanism of vascular calcification is not merely a consequence of a high-phosphorus and high-calcium environment but also an active process characterized by abnormal calcium phosphate deposition on blood vessel walls that involves various molecular mechanisms. Recent advances in bioinformatics approaches have led to increasing recognition that aberrant post-translational modifications (PTMs) play important roles in vascular calcification. This review presents the latest progress in clarifying the roles of PTMs, such as ubiquitination, acetylation, carbamylation and glycosylation, as well as signaling pathways, such as the Wnt/β-catenin pathway, in vascular calcification.

Association between Ward's triangle bone mineral density levels and abdominal aortic calcification: Data from the national health and nutrition examination survey 2013-2014

BACKGROUND & AIMS

Despite extensive research into the cardiovascular implications of abdominal aortic calcification (AAC), there is a scarcity of robust studies exploring its association with Ward's triangle bone mineral density (BMD). This study aimed to evaluate this relationship in a nationally representative sample and compare the predictive value with femoral neck BMD and total femur BMD.

METHODS

We conducted a cross-sectional analysis of 2013-2014 National Health and Nutrition Examination Survey (NHANES) data, utilizing a complex, stratified, multistage, cluster sampling design. BMD measurements at Ward's triangle, femoral neck, and total femur were assessed using DXA scans. AAC severity was defined by a Kauppila score of ≥5. Predictors of AAC-24 scores were identified through correlation and linear regression models. Stratified regression and restricted cubic splines were applied to explore subgroup and dose-response relationships.

RESULTS

Of the 2965 participants representing 116, 562, 500 individuals in the U.S., 11 % had severe AAC. Ward's triangle BMD showed a significant negative association with AAC-24 scores (β = -1.90, 95 % CI: -2.80 to -1.00, P < 0.002) and a reduced risk of severe AAC (OR = 0.85, 95 % CI: 0.76 to 0.95, P = 0.010). Non-linear associations were observed between Ward's triangle BMD and AAC outcomes. Ward's triangle BMD outperformed femoral neck and total femur BMD in predicting AAC.

CONCLUSIONS

Higher Ward's triangle BMD is linked to lower odds of severe AAC, highlighting its potential for improved early detection of AAC over femoral neck and total femur BMD. Healthcare providers should consider the implications of reduced Ward's triangle BMD for systemic atherosclerosis and recommend early AAC screening for enhanced cardiovascular risk management.

RANKL-mediated osteoclast formation is required for bone loss in a murine model of Staphylococcus aureus osteomyelitis

Staphylococcus aureus osteomyelitis leads to extensive bone destruction. Osteoclasts are bone resorbing cells that are often increased in bone infected with S. aureus. The cytokine RANKL is essential for osteoclast formation under physiological conditions but in vitro evidence suggests that inflammatory cytokines may by-pass the requirement for RANKL. The goal of this study was to determine whether RANKL-dependent osteoclast formation is essential for the bone loss that occurs in a murine model of S. aureus osteomyelitis. To this end, humanized-RANKL mice were infected by direct inoculation of S. aureus into a unicortical defect in the femur. Mice were treated with vehicle or denosumab, a human monoclonal antibody that inhibits RANKL, both before and during a 14-day infection period. The severe cortical bone destruction caused by infection was completely prevented by denosumab administration even though the bacterial burden in the femur was not affected. Osteoclasts were abundant near the inoculation site in vehicle-treated mice but absent in denosumab-treated mice. In situ hybridization demonstrated that S. aureus infection potently stimulated RANKL expression in bone marrow stromal cells. The extensive reactive bone formation that occurs in this osteomyelitis model was also reduced by denosumab administration. Lastly, there was a notable lack of osteoblasts near the infection site suggesting that the normal coupling of bone formation to bone resorption was disrupted by S. aureus infection. These results demonstrate that RANKL-mediated osteoclast formation is required for the bone loss that occurs in S. aureus infection and suggest that disruption of the coupling of bone formation to bone resorption may also contribute to bone loss in this condition.

The Hippo signalling pathway in bone homeostasis: Under the regulation of mechanics and aging

The Hippo signalling pathway is a conserved kinase cascade that orchestrates diverse cellular processes, such as proliferation, apoptosis, lineage commitment and stemness. With the onset of society ages, research on skeletal aging-mechanics-bone homeostasis has exploded. In recent years, aging and mechanical force in the skeletal system have gained groundbreaking research progress. Under the regulation of mechanics and aging, the Hippo signalling pathway has a crucial role in the development and homeostasis of bone. We synthesize the current knowledge on the role of the Hippo signalling pathway, particularly its downstream effectors yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), in bone homeostasis. We discuss the regulation of the lineage specification and function of different skeletal cell types by the Hippo signalling pathway. The interactions of the Hippo signalling pathway with other pathways, such as Wnt, transforming growth factor beta and nuclear factor kappa-B, are also mentioned because of their importance for modulating bone homeostasis. Furthermore, YAP/TAZ have been extensively studied as mechanotransducers. Due to space limitations, we focus on reviewing how mechanical forces and aging influence cell fate, communications and homeostasis through a dysregulated Hippo signalling pathway.

The Therapeutic Role of Genistein in Perimenopausal and Postmenopausal Women

Objective

We sought to review the biology and clinical benefits of genistein, a plant-derived isoflavone with emphasis on perimenopausal and postmenopausal women. The focus is on assessing its impact on skin health and aesthetics as well as bone density and cardiovascular and metabolic functions.

Methods

This narrative review used PubMed to collect studies relating to the biology and clinical effects of genistein on postmenopausal signs and symptoms, including bone density loss, metabolic issues and symptoms, and skin aging. Articles were selected based on relevance to the scope of genistein's influence on estrogen receptors and their downstream effects. This review included in vitro, in vivo, animal, and human studies.

Results

According to the current literature, genistein demonstrates efficacy in mitigating menopausal signs and symptoms such as hot flashes, bone density loss and rate of osteoporosis, and skin aging. It shows a protective effect against cardiovascular diseases by improving lipid profiles, weight changes, and reducing low-density lipoprotein cholesterol. It also displays benefits in increasing bone mineral density but has not displayed the side effects commonly associated with estrogen replacement. Regarding skin health, genistein appears to enhance photoprotection, wound healing, elasticity, and hydration, inhibits skin cancer, and reduces wrinkles.

Conclusion

Genistein acts as a selective estrogen receptor modulator (SERM) with benefits across a spectrum of menopausal signs and symptoms, presenting a viable alternative to estrogen replacement in perimenopausal and postmenopausal women. Its utility extends to improving cardiovascular health, bone density, and skin quality, making it a comprehensive treatment option for peri and postmenopausal women.

Effect of Denosumab or Alendronate on Vascular Calcification: Secondary Analysis of SALTIRE2 Randomized Controlled Trial

BACKGROUND

Patients with osteoporosis demonstrate increased vascular calcification but the effect of osteoporosis treatments on vascular calcification remains unclear. The present study aimed to examine whether coronary or aortic calcification are influenced by denosumab and alendronic acid treatment.

METHODS AND RESULTS

In a double-blind randomized controlled SALTIRE2 (Study Investigating the Effect of Drugs Used to Treat Osteoporosis on the Progression of Calcific Aortic Stenosis) trial, patients with aortic stenosis were randomized 2:1:2:1 to denosumab, placebo injection, alendronic acid, or placebo capsule. Participants underwent serial imaging with computed tomography and 18F-sodium fluoride positron emission tomography for the assessment of vascular calcium burden and calcification activity, respectively. We report the prespecified secondary analyses of 24-month change in coronary calcium score, and 12-month changes in thoracic aorta calcium score, coronary and aortic 18F-sodium fluoride activity. One hundred fifty patients with aortic stenosis (72±8 years; 21% female) were randomized to denosumab (n=49), alendronic acid (n=51), and placebo (injection n=25, capsule n=25). There were no differences in change in coronary calcium scores between placebo (16 [-64 to 148] Agatston units) and either denosumab (94 [0-212] Agatston units, P=0.24) or alendronic acid (34 [-62 to 134], P=0.99). There were no differences in change in thoracic aorta calcium scores between placebo (132 [22-512] Agatston units) and either denosumab (118 [11-340], P=0.75) or alendronic acid (116 [26-498] Agatston units, P=0.62). There were no differences in changes in coronary or aortic 18F-sodium fluoride activity between treatment groups.

CONCLUSIONS

Neither alendronic acid nor denosumab are associated with changes in the activity or progression of coronary or aortic calcification. Osteoporosis treatments do not appear to have major impact on vascular calcification of atherosclerosis.

REGISTRATION

https://www.clinicaltrials.gov; Unique identifier: NCT02132026.

The use of denosumab in osteoporosis - an update on efficacy and drug safety

INTRODUCTION

Denosumab (Prolia) is a fully human monoclonal antibody against the receptor activator of the nuclear factor kappaB ligand. It is a potent antiresorptive agent that reduces osteoclastogenesis.

AREAS COVERED

Denosumab has been shown to improve bone mineral density and reduce the incidence of new fractures in postmenopausal women and men. It is also used in the treatment of glucocorticoid-induced osteoporosis, as well as for the prevention of bone loss and reduction of fracture risk in men receiving androgen deprivation therapy for non-metastatic prostate cancer and women receiving adjuvant aromatase inhibitor therapy for breast cancer. Initial safety concerns included infections, cancer, skin reactions, cardiovascular disease, hypocalcemia, osteonecrosis of the jaw, and atypical femur fractures; however, further study and experience provide reassurance on these issues. Anecdotal reports have raised concerns about an increased risk of multiple vertebral fractures following discontinuation of denosumab.

EXPERT OPINION

Although bisphosphonates are often selected as initial therapy for osteoporosis, denosumab may be an appropriate initial therapy in patients at high risk for fracture, including older patients who have difficulty with the dosing requirements of oral bisphosphonates, as well as patients who are intolerant of, unresponsive to, or have contraindications to other therapies. Additional data is needed to address questions regarding treatment duration and discontinuation.

RANK-RANKL-OPG Axis in MASLD: Current Evidence Linking Bone and Liver Diseases and Future Perspectives

Metabolic dysfunction-associated steatotic liver disease (MASLD)-and its worse form, metabolic-associated steatohepatitis (MASH), characterised by inflammation and liver damage-corresponds to the liver's involvement in metabolic syndrome, which constitutes an economic burden for healthcare systems. However, the biomolecular pathways that contribute to steatotic liver disease are not completely clear. Abnormalities of bone metabolism are frequent in people affected by metabolic liver disease, with reduced bone density and an increased risk of fracture. Receptor activator of NF-κB (RANK), receptor activator of NF-κB ligand (RANKL), and osteoprotegerin(OPG) are critical regulators of bone metabolism, performing pleiotropic effects, and may have potential involvement in metabolic disorders like MASLD, resulting in a topic of great interest and intrigue. This narrative review aims to investigate this potential role and its implications in MASLD development and progression and in hepatocellular carcinoma, which represents its worst complication.

An Exploration of the Role of Osteoclast Lineage Cells in Bone Tissue Engineering

Bone defects because of age, trauma, and surgery, which are exacerbated by medication side effects and common diseases such as osteoporosis, diabetes, and rheumatoid arthritis, are a problem of epidemic scale. The present clinical standard for treating these defects includes autografts and allografts. Although both treatments can promote robust regenerative outcomes, they fail to strike a desirable balance of availability, side effect profile, consistent regenerative efficacy, and affordability. This difficulty has contributed to the rise of bone tissue engineering (BTE) as a potential avenue through which enhanced bone regeneration could be delivered. BTE is founded upon a paradigm of using biomaterials, bioactive factors, osteoblast lineage cells (ObLCs), and vascularization to cue deficient bone tissue into a state of regeneration. Despite promising preclinical results, BTE has had modest success in being translated into the clinical setting. One barrier has been the simplicity of its paradigm relative to the complexity of biological bone. Therefore, this paradigm must be critically examined and expanded to better account for this complexity. One potential avenue for this is a more detailed consideration of osteoclast lineage cells (OcLCs). Although these cells ostensibly oppose ObLCs and bone regeneration through their resorptive functions, a myriad of investigations have shed light on their potential to influence bone equilibrium in more complex ways through their interactions with both ObLCs and bone matrix. Most BTE research has not systematically evaluated their influence. Yet contrary to expectations associated with the paradigm, a selection of BTE investigations has demonstrated that this influence can enhance bone regeneration in certain contexts. In addition, much work has elucidated the role of many controllable scaffold parameters in both inhibiting and stimulating the activity of OcLCs in parallel to bone regeneration. Therefore, this review aims to detail and explore the implications of OcLCs in BTE and how they can be leveraged to improve upon the existing BTE paradigm.

Serum levels of soluble receptor activator for nuclear factor kB ligand play a crucial role in the association of osteoprotegerin with coronary artery disease

Osteoprotegerin (OPG) is a soluble decoy receptor for receptor activator of nuclear factor kB ligand (RANKL), and is implicated in the pathogenesis of atherosclerosis. The aim of the present study was to examine the hypothesis that serum OPG concentrations are increased in patients with stable coronary artery disease (CAD) at different serum levels of soluble RANKL (sRANKL). The study used a case-control design in which consecutively hospitalized individuals were recruited. Fasting blood samples were taken upon admission for serum testing. Participants with previously diagnosed CAD that was asymptomatic or had controlled symptoms constituted the stable CAD group, whereas patients with negative coronary computed tomography angiography results constituted the control non-CAD group. Exclusion criteria included recent acute coronary syndrome, severe heart failure, CAD-complicating autoimmune, blood or thyroid diseases, cancer, elevated temperature with or without infection, severe liver or kidney dysfunction, abnormal calcium metabolism, recent surgery and trauma history. A total of 118 individuals were included in the study. Smoothed plots generated using the recursive method and multivariate models showed that the incidence of stable CAD increased with serum OPG level up to the turning point of 18 pg/ml. This trend was observed at both high [odds ratio (OR), 1.61; 95% confidence interval (CI), 1.04-2.50; P=0.032) and low sRANKL concentrations (OR, 1.52; 95% CI, 1.06-2.17; P=0.022) after adjustment for cardiovascular risk factors. In conclusion, serum OPG levels ≤18 pg/ml are positively associated with stable CAD, regardless of sRANKL levels. In addition, at the same serum OPG level, higher sRANKL levels are associated with a greater incidence of stable CAD compared with lower sRANKL levels. This study identified the relationship between OPG, sRANKL, and stable CAD, and established the reference range for future clinical use.

Converging Mechanisms of Vascular and Cartilaginous Calcification

Physiological calcification occurs in bones and epiphyseal cartilage as they grow, whereas ectopic calcification occurs in blood vessels, cartilage, and soft tissues. Although it was formerly thought to be a passive and degenerative process associated with aging, ectopic calcification has been identified as an active cell-mediated process resembling osteogenesis, and an increasing number of studies have provided evidence for this paradigm shift. A significant association between vascular calcification and cardiovascular risk has been demonstrated by various studies, which have shown that arterial calcification has predictive value for future coronary events. With respect to cartilaginous calcification, calcium phosphate or hydroxyapatite crystals can form asymptomatic deposits in joints or periarticular tissues, contributing to the pathophysiology of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, tendinitis, and bursitis. The risk factors and sequence of events that initiate ectopic calcification, as well as the mechanisms that prevent the development of this pathology, are still topics of debate. Consequently, in this review, we focus on the nexus of the mechanisms underlying vascular and cartilaginous calcifications, trying to circumscribe the similarities and disparities between them to provide more clarity in this regard.

RANKL signaling drives skeletal muscle into the oxidative profile

The bone-muscle unit refers to the reciprocal regulation between bone and muscle by mechanical interaction and tissue communication via soluble factors. The RANKL stimulation induces mitochondrial biogenesis and increases the oxidative capacity in osteoclasts and adipocytes. RANKL may bind to the membrane bound RANK or to osteoprotegerin (OPG), a decoy receptor that inhibits RANK-RANKL activation. RANK is highly expressed in skeletal muscle, but the contribution of RANKL to healthy skeletal muscle fiber remains elusive. Here we show that RANKL stimulation in C2C12-derived myotubes induced activation of mitochondrial biogenesis pathways as detected by RNA-seq and western blot. RANKL expanded the mitochondrial reticulum, as shown by mitochondrial DNA quantification and MitoTracker staining, and boosted the spare respiratory capacity. Using MEK and MAPK inhibitors, we found that RANKL signals via ERK and p38 to induce mitochondrial biogenesis. The soleus from OPG-/- and OPG+/- mice showed higher respiratory rates compared to C57BL6/J WT mice, which correlates with high serum RANKL levels. RANKL infusion using a mini-osmotic pump in WT mice increased the number of mitochondria, boosted the respiratory rate, increased succinate dehydrogenase activity in skeletal muscle, and improved the fatigue resistance of gastrocnemius. Therefore, our findings reveal a new role of RANKL as an osteokine-like protein that impacts muscle fiber metabolism.

Preclinical Rodent Models for Human Bone Disease, Including a Focus on Cortical Bone

Preclinical models (typically ovariectomized rats and genetically altered mice) have underpinned much of what we know about skeletal biology. They have been pivotal for developing therapies for osteoporosis and monogenic skeletal conditions, including osteogenesis imperfecta, achondroplasia, hypophosphatasia, and craniodysplasias. Further therapeutic advances, particularly to improve cortical strength, require improved understanding and more rigorous use and reporting. We describe here how trabecular and cortical bone structure develop, are maintained, and degenerate with aging in mice, rats, and humans, and how cortical bone structure is changed in some preclinical models of endocrine conditions (eg, postmenopausal osteoporosis, chronic kidney disease, hyperparathyroidism, diabetes). We provide examples of preclinical models used to identify and test current therapies for osteoporosis, and discuss common concerns raised when comparing rodent preclinical models to the human skeleton. We focus especially on cortical bone, because it differs between small and larger mammals in its organizational structure. We discuss mechanisms common to mouse and human controlling cortical bone strength and structure, including recent examples revealing genetic contributors to cortical porosity and osteocyte network configurations during growth, maturity, and aging. We conclude with guidelines for clear reporting on mouse models with a goal for better consistency in the use and interpretation of these models.

Irisin prevents trabecular bone damage and tumor invasion in a mouse model of multiple myeloma

Bone disease associated with multiple myeloma (MM) is characterized by osteolytic lesions and pathological fractures, which remain a therapeutic priority despite new drugs improving MM patient survival. Antiresorptive molecules represent the main option for the treatment of MM-associated bone disease (MMBD), whereas osteoanabolic molecules are under investigation. Among these latter, we here focused on the myokine irisin, which is able to enhance bone mass in healthy mice, prevent bone loss in osteoporotic mouse models, and accelerate fracture healing in mice. Therefore, we investigated irisin effect on MMBD in a mouse model of MM induced by intratibial injection of myeloma cells followed by weekly administration of 100 μg/kg of recombinant irisin for 5 wk. By micro-Ct analysis, we demonstrated that irisin improves MM-induced trabecular bone damage by partially preventing the reduction of femur Trabecular Bone Volume/Total Volume (P = .0028), Trabecular Number (P = .0076), Trabecular Fractal Dimension (P = .0044), and increasing Trabecular Separation (P = .0003) in MM mice. In cortical bone, irisin downregulates the expression of Sclerostin, a bone formation inhibitor, and RankL, a pro-osteoclastogenic molecule, while in BM it upregulates Opg, an anti-osteoclastogenic cytokine. We found that in the BM tibia of irisin-treated MM mice, the percentage of MM cells displays a reduction trend, while in the femur it decreases significantly. This is in line with the in vitro reduction of myeloma cell viability after 48 h of irisin stimulation at both 200 and 500 ng/mL and, after 72 h already at 100 ng/mL rec-irisin. These results could be due to irisin ability to downregulate the expression of Notch 3, which is important for cell-to-cell communication in the tumor niche, and Cyclin D1, supporting an inhibitory effect of irisin on MM cell proliferation. Overall, our findings suggest that irisin could be a new promising strategy to counteract MMBD and tumor burden in one shot.

Osteoprotegerin Is Essential for the Development of Endothelial Dysfunction Induced by Angiotensin II in Mice

Opinions on the effects of osteoprotegerin (OPG) have evolved over the years from a protein protecting the vasculature from calcification to a cardiovascular risk factor contributing to inflammation within the vascular wall. Nowadays, the link between OPG and angiotensin II (Ang II) appears to be particularly important. In this study, the endothelial function was investigated in OPG-knockout mice (B6.129.S4-OPG, OPG-) and wild-type (C57BL/6J, OPG+) mice under basic conditions and after Ang II exposure by assessing the endothelium-dependent diastolic response of aortic rings to acetylcholine in vitro. A further aim of the study was to compare the effect of Ang II on the expression of cytokines in the aortic wall of both groups of mice. Our study shows that rings from OPG- mice had their normal endothelial function preserved after incubation with Ang II, whereas those from OPG+ mice showed significant endothelial dysfunction. We conclude that the absence of OPG, although associated with a pro-inflammatory cytokine profile in the vascular wall, simultaneously protects against Ang II-induced increases in pro-inflammatory cytokines in the murine vascular wall. Our study also demonstrates that the absence of OPG can result in a decrease in the concentration of pro-inflammatory cytokines in the vascular wall after Ang II exposure. The presence of OPG is therefore crucial for the development of Ang II-induced inflammation in the vascular wall and for the development of Ang II-induced endothelial dysfunction.

Current Prognostic Biomarkers for Abdominal Aortic Aneurysm: A Comprehensive Scoping Review of the Literature

Abdominal aortic aneurysm (AAA) is a progressive dilatation of the aorta that can lead to aortic rupture. The pathophysiology of the disease is not well characterized but is known to be caused by the general breakdown of the extracellular matrix within the aortic wall. In this comprehensive literature review, all current research on proteins that have been investigated for their potential prognostic capabilities in patients with AAA was included. A total of 45 proteins were found to be potential prognostic biomarkers for AAA, predicting incidence of AAA, AAA rupture, AAA growth, endoleak, and post-surgical mortality. The 45 proteins fell into the following seven general categories based on their primary function: (1) cardiovascular health, (2) hemostasis, (3) transport proteins, (4) inflammation and immunity, (5) kidney function, (6) cellular structure, (7) and hormones and growth factors. This is the most up-to-date literature review on current prognostic markers for AAA and their functions. This review outlines the wide pathophysiological processes that are implicated in AAA disease progression.

Osteoporosis treatments for intervertebral disc degeneration and back pain: a perspective

Low back pain derived from intervertebral disc (IVD) degeneration is a debilitating spinal condition that, despite its prevalence, does not have any intermediary guidelines for pharmacological treatment between palliative care and invasive surgery. The development of treatments for the IVD is complicated by the variety of resident cell types needed to maintain the regionally distinct structural properties of the IVD that permit the safe, complex motions of the spine. Osteoporosis of the spine increases the risk of vertebral bone fracture that can increase the incidence of back pain. Fortunately, there are a variety of pharmacological treatments for osteoporosis that target osteoblasts, osteoclasts and/or osteocytes to build bone and prevent vertebral fracture. Of particular note, clinical and preclinical studies suggest that commonly prescribed osteoporosis drugs like bisphosphonates, intermittent parathyroid hormone, anti-sclerostin antibody, selective estrogen receptor modulators and anti-receptor activator of nuclear factor-kappa B ligand inhibitor denosumab may also relieve back pain. Here, we cite clinical and preclinical studies and include unpublished data to support the argument that a subset of these therapeutics for osteoporosis may alleviate low back pain by also targeting the IVD.

Oncostatin M suppresses bone morphogenetic protein-4-induced osteoprotegerin synthesis in MC3T3-E1 osteoblast-like cells: p70 S6 kinase attenuation

Evidence is accumulating that osteal macrophages, in addition to bone-resorbing osteoclasts and bone-forming osteoblasts, participate vitally in bone remodeling process. Oncostatin M (OSM), an inflammatory cytokine belonging to interleukin-6 superfamily, is recognized as an essential factor secreted by osteal macrophages to orchestrate bone remodeling. Osteoprotegerin (OPG) produced by osteoblasts regulates osteoclastogenesis. We have reported that bone morphogenetic protein-4 (BMP-4) stimulates OPG synthesis in MC3T3-E1 osteoblast-like cells, and that SMAD1/5/8(9), p38 mitogen-activated protein kinase (MAPK), and p70 S6 kinase are involved in the OPG synthesis. The present study aims to investigate the effect of OSM on the synthesis of OPG stimulated by BMP-4 in osteoblasts. OSM suppressed the release and the mRNA expression of OPG upregulated by BMP-4 in MC3T3-E1 cells. Neither the BMP-4-induced phosphorylation of SMAD1/5/9 nor that of p38 MAPK was affected by OSM. On the other hand, the phosphorylation of p70 S6 kinase stimulated by BMP-4 was considerably suppressed by OSM. These results strongly suggest that OSM suppresses the BMP-4-stimulated OPG synthesis via inhibition of the p70 S6 kinase-mediated pathway in osteoblast-like cells.

Prognostic effect of osteoprotegerin in patients with ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Osteoprotegerin (OPG) is supposed to participate in the development of atherosclerosis and cardio-cerebrovascular disease. However, the results of research on relationship between OPG and ischemic stroke (IS) are controversial. Therefore, we carried out the first systematic review and meta-analysis to evaluate prognostic effect of osteoprotegerin in patients with IS.

METHODS

We comprehensively searched databases of PubMed, Embase, and the Cochrane Library through 21 August 2023 to identify observational studies that evaluated effect of OPG on poor functional outcome (modified Rankin Scale [mRS] Score of 3-6) and mortality in patients with IS. Adjusted odds ratios (aOR) with a 95% confidence interval (CI) of each included study were used as much as possible to assess the pooled effect.

RESULTS

Five studies that enrolled 4,506 patients in total fulfilled our inclusion criteria. Three studies were included in the pooled analysis for each endpoint since one of the included studies had provided data on poor functional outcome as well as mortality. OPG was neither associated with poor functional outcome (aOR 1.29, 95% CI 0.90-1.85) nor with mortality (aOR 1.57, 95% CI 0.90-2.74) in patients with IS.

CONCLUSIONS

There is insufficient evidence to demonstrate the correlation between OPG and mortality or poor functional outcome in IS patients. OPG cannot be applied to predict worse neurological function in IS patients based on the current evidence.

RANKL, but Not R-Spondins, Is Involved in Vascular Smooth Muscle Cell Calcification through LGR4 Interaction

Vascular calcification has a global health impact that is closely linked to bone loss. The Receptor Activator of Nuclear Factor Kappa B (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system, fundamental for bone metabolism, also plays an important role in vascular calcification. The Leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4), a novel receptor for RANKL, regulates bone remodeling, and it appears to be involved in vascular calcification. Besides RANKL, LGR4 interacts with R-spondins (RSPOs), which are known for their roles in bone but are less understood in vascular calcification. Studies were conducted in rats with chronic renal failure fed normal or high phosphorus diets for 18 weeks, with and without control of circulating parathormone (PTH) levels, resulting in different degrees of aortic calcification. Additionally, vascular smooth muscle cells (VSMCs) were cultured under non-calcifying (1 mM phosphate) and calcifying (3 mM phosphate) media with different concentrations of PTH. To explore the role of RANKL in VSMC calcification, increasing concentrations of soluble RANKL were added to non-calcifying and calcifying media. The effects mediated by RANKL binding to its receptor LGR4 were investigated by silencing the LGR4 receptor in VSMCs. Furthermore, the gene expression of the RANK/RANKL/OPG system and the ligands of LGR4 was assessed in human epigastric arteries obtained from kidney transplant recipients with calcification scores (Kauppila Index). Increased aortic calcium in rats coincided with elevated systolic blood pressure, upregulated Lgr4 and Rankl gene expression, downregulated Opg gene expression, and higher serum RANKL/OPG ratio without changes in Rspos gene expression. Elevated phosphate in vitro increased calcium content and expression of Rankl and Lgr4 while reducing Opg. Elevated PTH in the presence of high phosphate exacerbated the increase in calcium content. No changes in Rspos were observed under the conditions employed. The addition of soluble RANKL to VSMCs induced genotypic differentiation and calcification, partly prevented by LGR4 silencing. In the epigastric arteries of individuals presenting vascular calcification, the gene expression of RANKL was higher. While RSPOs show minimal impact on VSMC calcification, RANKL, interacting with LGR4, drives osteogenic differentiation in VSMCs, unveiling a novel mechanism beyond RANKL-RANK binding.

An integrated multi-omics analysis reveals osteokines involved in global regulation

Bone secretory proteins, termed osteokines, regulate bone metabolism and whole-body homeostasis. However, fundamental questions as to what the bona fide osteokines and their cellular sources are and how they are regulated remain unclear. In this study, we analyzed bone and extraskeletal tissues, osteoblast (OB) conditioned media, bone marrow supernatant (BMS), and serum, for basal osteokines and those responsive to aging and mechanical loading/unloading. We identified 375 candidate osteokines and their changes in response to aging and mechanical dynamics by integrating data from RNA-seq, scRNA-seq, and proteomic approaches. Furthermore, we analyzed their cellular sources in the bone and inter-organ communication facilitated by them (bone-brain, liver, and aorta). Notably, we discovered that senescent OBs secrete fatty-acid-binding protein 3 to propagate senescence toward vascular smooth muscle cells (VSMCs). Taken together, we identified previously unknown candidate osteokines and established a dynamic regulatory network among them, thus providing valuable resources to further investigate their systemic roles.

Genetics of ischemic stroke functional outcome

Ischemic stroke, which accounts for 87% of cerebrovascular accidents, is responsible for massive global burden both in terms of economic cost and personal hardship. Many stroke survivors face long-term disability-a phenotype associated with an increasing number of genetic variants. While clinical variables such as stroke severity greatly impact recovery, genetic polymorphisms linked to functional outcome may offer physicians a unique opportunity to deliver personalized care based on their patient's genetic makeup, leading to improved outcomes. A comprehensive catalogue of the variants at play is required for such an approach. In this review, we compile and describe the polymorphisms associated with outcome scores such as modified Rankin Scale and Barthel Index. Our search identified 74 known genetic polymorphisms spread across 48 features associated with various poststroke disability metrics. The known variants span diverse biological systems and are related to inflammation, vascular homeostasis, growth factors, metabolism, the p53 regulatory pathway, and mitochondrial variation. Understanding how these variants influence functional outcome may be helpful in maximizing poststroke recovery.

Is RANKL a potential molecular target in osteoarthritis?

OBJECTIVE

Osteoarthritis (OA) is a disease of joints, in which the bone under the articular cartilage undergoes increased remodelling activity. The question is whether a better understanding of the causes and mechanisms of bone remodelling can predict disease-modifying treatments.

DESIGN

This review summarises the current understanding of the aetiology of OA, with an emphasis on events in the subchondral bone (SCB), and the cells and cytokines involved, to seek an answer to this question.

RESULTS

SCB remodelling across OA changes the microstructure of the SCB, which alters the load-bearing properties of the joint and seems to have an important role in the initiation and progression of OA. Bone remodelling is tightly controlled by numerous cytokines, of which Receptor Activator of NFκB ligand (RANKL) and osteoprotegerin are central factors in almost all known bone conditions. In terms of finding therapeutic options for OA, an important question is whether controlling the rate of SCB remodelling would be beneficial. The role of RANKL in the pathogenesis and progression of OA and the effect of its neutralisation remain to be clarified.

CONCLUSIONS

This review further makes the case for SCB remodelling as important in OA and for additional study of RANKL in OA, both its pathophysiological role and its potential as an OA disease target.

Sex- and Age-Specific Prevalence of Osteopenia and Osteoporosis: Sampling Survey

BACKGROUND

Osteopenia and osteoporosis are posing a long-term influence on the aging population's health contributing to a higher risk of mortality, loss of autonomy, hospitalization, and huge health system costs and social burden. Therefore, more pertinent data are needed to demonstrate the current state of osteoporosis.

OBJECTIVE

This sampling survey seeks to assess the trends in the prevalence of osteopenia and osteoporosis in a Chinese Han population.

METHODS

A community-based cross-sectional study involving 16,377 participants used a multistage sampling method. Bone mineral density was measured using the quantitative ultrasonic densitometry. Student t test and Mann-Whitney U test were used to test the difference between normally and nonnormally distributed quantitative variables between male and female participants. A chi-square (χ2) test was used to compare categorized variables. Stratified analysis was conducted to describe the prevalence rates of osteoporosis (T score ≤-2.5) and osteopenia (T score -2.5 to -1.0) across age, sex, calcium intake, and menopause. A direct standardization method was used to calculate the age-standardized prevalence rates of osteoporosis and osteopenia. T-score was further categorized into quartiles (T1-T4) by age- and sex-specified groups.

RESULTS

The prevalence rates of osteopenia and osteoporosis were 40.5% (6633/16,377) and 7.93% (1299/16,377), respectively, and the age-standardized prevalence rates were 27.32% (287,877,129.4/1,053,861,940) and 3.51% (36,974,582.3/1,053,861,940), respectively. There was an increase in osteopenia and osteoporosis prevalence from 21.47% (120/559) to 56.23% (754/1341) and 0.89% (5/559) to 17.23% (231/1341), respectively, as age increased from 18 years to 75 years old. The prevalence rates of osteopenia and osteoporosis were significantly higher in female participants (4238/9645, 43.94% and 1130/9645, 11.72%) than in male participants (2395/6732, 35.58% and 169/6732, 2.51%; P<.001), and in postmenopausal female participants (3638/7493, 48.55% and 1053/7493, 14.05%) than in premenopausal female participants (538/2026, 26.55% and 53/2026, 2.62%; P<.001). In addition, female participants with a history of calcium intake had a lower osteoporosis prevalence rate than female participants without any history of calcium intake in all age groups (P=.004). From low quartile to high quartile of T-score, the prevalence of diabetes mellitus (752/4037, 18.63%; 779/4029, 19.33%; 769/3894, 19.75%; and 869/3879, 22.4%) and dyslipidemia (2228/4036, 55.2%; 2304/4027, 57.21%; 2306/3891, 59.26%; and 2379/3878, 61.35%) were linearly increased (P<.001), while the prevalence of cancer (112/4037, 2.77%; 110/4029, 2.73%; 103/3894, 2.65%; and 77/3879, 1.99%) was decreased (P=.03).

CONCLUSIONS

Our data imply that as people age, osteopenia and osteoporosis are more common in females than in males, particularly in postmenopausal females than in premenopausal females, and bone mineral density significantly affects the prevalence of chronic diseases. These findings offer information that can be applied to intervention programs meant to prevent or lessen the burden of osteoporosis in China.

Gallein but not fluorescein enhances the PGD2-stimulated synthesis of osteoprotegerin and interleukin-6 in osteoblasts: Amplification of osteoprotegerin/interleukin-6 by gallein

Gallein, a small molecule related to fluorescein, is established as an inhibitor of Gβγ subunits to inhibit G protein (Gs) signaling. This agent is providing a potential therapeutic strategy to ameliorate organ dysfunctions especially involved in inflammation, however; the effects on bone metabolism have not yet been clarified. Prostaglandins (PGs) play important roles as autacoids including osteoblasts, and d-type prostanoid (DP) receptor, a member of G protein-coupled receptor specific to PGD2, is expressed on osteoblasts. We previously reported that prostaglandin D2 (PGD2) induces the syntheses of osteoprotegerin (OPG) and interleukin-6 (IL-6), essential factors in bone remodelling process, and p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK), and p44/p42 MAPK are involved in the signal transduction of PGD2 in osteoblast-like MC3T3-E1 cells. Thus, we investigated in this study that the effect and the underlying mechanism of gallein, an inhibitor Gβɤ subunits, on the syntheses of OPG and IL-6 induced by PGD2 in these cells. The cultured cells were treated with gallein or fluorescein, a structurally related compound inactive to Gβɤ subunits, and subsequently stimulated with PGD2. Not fluorescein but gallein amplified the PGD2-stimulated releases of OPG and IL-6. Gallein enhanced the PGD2-upregulated mRNA expression levels of OPG and IL-6. Regarding the signaling mechanism, gallein did not affect the PGD2-induced phosphorylation of p38 MAPK, JNK, or p42 MAPK. In conclusion, gallein upregulates the PGD2-stimulated syntheses of OPG and IL-6 by the specific effect to inhibit Gβγ subunits in osteoblasts, but the effect is not exerted at the upstream of p38 MAPK, JNK, or p44/p42 MAPK activation.

Novel Biomarkers of Bone Metabolism

Bone represents a metabolically active tissue subject to continuous remodeling orchestrated by the dynamic interplay between osteoblasts and osteoclasts. These cellular processes are modulated by a complex interplay of biochemical and mechanical factors, which are instrumental in assessing bone remodeling. This comprehensive evaluation aids in detecting disorders arising from imbalances between bone formation and reabsorption. Osteoporosis, characterized by a reduction in bone mass and strength leading to heightened bone fragility and susceptibility to fractures, is one of the more prevalent chronic diseases. Some epidemiological studies, especially in patients with chronic kidney disease (CKD), have identified an association between osteoporosis and vascular calcification. Notably, low bone mineral density has been linked to an increased incidence of aortic calcification, with shared molecules, mechanisms, and pathways between the two processes. Certain molecules emerging from these shared pathways can serve as biomarkers for bone and mineral metabolism. Detecting and evaluating these alterations early is crucial, requiring the identification of biomarkers that are reliable for early intervention. While traditional biomarkers for bone remodeling and vascular calcification exist, they suffer from limitations such as low specificity, low sensitivity, and conflicting results across studies. In response, efforts are underway to explore new, more specific biomarkers that can detect alterations at earlier stages. The aim of this review is to comprehensively examine some of the emerging biomarkers in mineral metabolism and their correlation with bone mineral density, fracture risk, and vascular calcification as well as their potential use in clinical practice.

Neutrophil extracellular traps mediate bone erosion in rheumatoid arthritis by enhancing RANKL-induced osteoclastogenesis

BACKGROUND AND PURPOSE

Rheumatoid arthritis (RA) is a chronic autoimmune disease that can cause bone erosion due to increased osteoclastogenesis. Neutrophils involvement in osteoclastogenesis remains uncertain. Given that neutrophil extracellular traps (NETs) can act as inflammatory mediators in rheumatoid arthritis, we investigated the role of NETs in stimulating bone loss by potentiating osteoclastogenesis during arthritis.

EXPERIMENTAL APPROACH

The level of NETs in synovial fluid from arthritis patients was assessed. Bone loss was evaluated by histology and micro-CT in antigen-induced arthritis (AIA)-induced WT mice treated with DNase or in Padi4-deficient mice (Padi4flox/flox LysMCRE ). The size and function of osteoclasts and the levels of RANKL and osteoprotegerin (OPG) released by osteoblasts that were incubated with NETs were measured. The expression of osteoclastogenic marker genes and protein levels were evaluated by qPCR and western blotting. To assess the participation of TLR4 and TLR9 in osteoclastogenesis, cells from Tlr4-/- and Tlr9-/- mice were cultured with NETs.

KEY RESULTS

Rheumatoid arthritis patients had higher levels of NETs in synovial fluid than osteoarthritis patients, which correlated with increased levels of RANKL/OPG. Moreover, patients with bone erosion had higher levels of NETs. Inhibiting NETs with DNase or Padi4 deletion alleviated bone loss in arthritic mice. Consistently, NETs enhanced RANKL-induced osteoclastogenesis that was dependent on TLR4 and TLR9 and increased osteoclast resorptive functions in vitro. In addition, NETs stimulated the release of RANKL and inhibited osteoprotegerin in osteoblasts, favouring osteoclastogenesis.

CONCLUSIONS AND IMPLICATIONS

Inhibiting NETs could be an alternative strategy to reduce bone erosion in arthritis patients.

The Complex Mechanisms and the Potential Effects of Statins on Vascular Calcification: A Narrative Review

Vascular calcification (VC) is a complex process of calcium deposition on the arterial wall and atherosclerotic plaques and involves interaction between vascular smooth muscle cells, inflammatory and VC mediators. The latter are independent predictors of cardiovascular morbidity and mortality and potential targets of pharmaceutical therapy. This paper is a narrative review of the complex mechanisms of VC development and in this context the potential anti-atherosclerotic effects of statins. At the initial stages of atherosclerosis VC correlates with atherosclerosis burden and in the long-term with cardiovascular morbidity and mortality. A plethora of animal and clinical studies have proposed statins as the cornerstone of primary and secondary prevention of atherosclerotic cardiovascular disease. Based on coronary computed tomography data, high doses of statins may have negligible or even positive effects on the progression of coronary artery calcification. Growing data support an increase in atherosclerotic plaque calcification in peripheral arteries (e.g., carotids), after long-term, statin-therapy. Despite the paradox of increasing VC, those effects of statins have been associated with higher plaque stability, reducing the risk of consequent adverse events. Statins seem to promote a "favorable" atherosclerotic calcification, suppressing atherosclerotic lesion expansion and their vulnerability. More studies are required to clarify the underlying mechanisms.

The Purinergic Nature of Pseudoxanthoma Elasticum

Pseudoxanthoma Elasticum (PXE) is an inherited disease characterized by elastic fiber calcification in the eyes, the skin and the cardiovascular system. PXE results from mutations in ABCC6 that encodes an ABC transporter primarily expressed in the liver and kidneys. It took nearly 15 years after identifying the gene to better understand the etiology of PXE. ABCC6 function facilitates the efflux of ATP, which is sequentially hydrolyzed by the ectonucleotidases ENPP1 and CD73 into pyrophosphate (PPi) and adenosine, both inhibitors of calcification. PXE, together with General Arterial Calcification of Infancy (GACI caused by ENPP1 mutations) as well as Calcification of Joints and Arteries (CALJA caused by NT5E/CD73 mutations), forms a disease continuum with overlapping phenotypes and shares steps of the same molecular pathway. The explanation of these phenotypes place ABCC6 as an upstream regulator of a purinergic pathway (ABCC6 → ENPP1 → CD73 → TNAP) that notably inhibits mineralization by maintaining a physiological Pi/PPi ratio in connective tissues. Based on a review of the literature and our recent experimental data, we suggest that PXE (and GACI/CALJA) be considered as an authentic "purinergic disease". In this article, we recapitulate the pathobiology of PXE and review molecular and physiological data showing that, beyond PPi deficiency and ectopic calcification, PXE is associated with wide and complex alterations of purinergic systems. Finally, we speculate on the future prospects regarding purinergic signaling and other aspects of this disease.

Psoriasis, bone and bowel: a comprehensive review and new insights

Psoriasis is a chronic immune-mediated disorder affecting about 2% of the population worldwide which is associated with significant morbidity. The disease usually presents as raised, well-demarcated erythematous plaques with adherent silvery scales. Psoriasis can appear at any age but it has two peaks occurring at 15–20 and 55–60 years of age. It affects males and females equally. Despite the multitude of investigations about psoriasis and even development of drugs with satisfactory results, its pathogenesis is not fully understood yet and its course is unpredictable. Various environmental triggers, e.g., obesity, stress and drugs may induce disease in genetically susceptible patients. Although psoriasis was considered primarily as a disease of the skin, more investigations have been revealed its systemic nature. Psoriatic arthritis (PsA) may complicate up to one-third of cases of psoriasis vulgaris (PV). Also, the association between psoriasis and a variety of other immune-mediated disorders such as inflammatory bowel disease (IBD) and celiac disease (CD) has been confirmed in various studies. Moreover, a growing body of evidences indicates that psoriasis shares some common histological and phenotypical properties with the spectrum of osteoimmunological diseases such as Paget’s disease of bone (PDB). Thus, exploring the common molecular and genetic mechanisms underlying psoriasis and related disorders is of paramount importance for better elucidating disease pathogenesis and designing more targeted treatments.

Emerging Role of Non-collagenous Bone Proteins as Osteokines in Extraosseous Tissues

Bone is a unique tissue, composed of various types of cells embedded in a calcified extracellular matrix (ECM), whose dynamic structure consists of organic and inorganic compounds produced by bone cells. The main inorganic component is represented by hydroxyapatite, whilst the organic ECM is primarily made up of type I collagen and non-collagenous proteins. These proteins play an important role in bone homeostasis, calcium regulation, and maintenance of the hematopoietic niche. Recent advances in bone biology have highlighted the importance of specific bone proteins, named "osteokines", possessing endocrine functions and exerting effects on nonosseous tissues. Accordingly, osteokines have been found to act as growth factors, cell receptors, and adhesion molecules, thus modifying the view of bone from a static tissue fulfilling mobility to an endocrine organ itself. Since bone is involved in a paracrine and endocrine cross-talk with other tissues, a better understanding of bone secretome and the systemic roles of osteokines is expected to provide benefits in multiple topics: such as identification of novel biomarkers and the development of new therapeutic strategies. The present review discusses in detail the known osseous and extraosseous effects of these proteins and the possible respective clinical and therapeutic significance.

Evaluating the potential of Vitamin D and curcumin to alleviate inflammation and mitigate the progression of osteoarthritis through their effects on human chondrocytes: A proof-of-concept investigation

Osteoarthritis (OA) is a chronic degenerative joint disorder primarily affecting the elderly, characterized by a prominent inflammatory component. The long-term side effects associated with current therapeutic approaches necessitate the development of safer and more efficacious alternatives. Nutraceuticals, such as Vitamin D and curcumin, present promising therapeutic potentials due to their safety, efficacy, and cost-effectiveness. In this study, we utilized a proinflammatory human chondrocyte model of OA to assess the anti-inflammatory properties of Vitamin D and curcumin, with a particular focus on the Protease-Activated Receptor-2 (PAR-2) mediated inflammatory pathway. Employing a robust siRNA approach, we effectively modulated the expression of PAR-2 to understand its role in the inflammatory process. Our results reveal that both Vitamin D and curcumin attenuate the expression of PAR-2, leading to a reduction in the downstream proinflammatory cytokines, such as Tumor Necrosis Factor-alpha (TNF-α), Interleukin 6 (IL-6), and Interleukin 8 (IL-8), implicated in the OA pathogenesis. Concurrently, these compounds suppressed the expression of Receptor Activator of Nuclear Factor kappa-Β Ligand (RANKL) and its receptor RANK, which are associated with PAR-2 mediated TNF-α stimulation. Additionally, Vitamin D and curcumin downregulated the expression of Interferon gamma (IFN-γ), known to elevate RANKL levels, underscoring their potential therapeutic implications in OA. This study, for the first time, provides evidence of the mitigating effect of Vitamin D and curcumin on PAR-2 mediated inflammation, employing an siRNA approach in OA. Thus, our findings pave the way for future research and the development of novel, safer, and more effective therapeutic strategies for managing OA.

High Phosphate-Induced JAK-STAT Signalling Sustains Vascular Smooth Muscle Cell Inflammation and Limits Calcification

Vascular calcification (VC) is an age-related complication characterised by calcium-phosphate deposition in the arterial wall driven by the osteogenic transformation of vascular smooth muscle cells (VSMCs). The JAK-STAT pathway is an emerging target in inflammation. Considering the relationship between VC and inflammation, we investigated the role of JAK-STAT signalling during VSMC calcification. Human aortic smooth muscle cells (HASMCs) were cultured in high-inorganic phosphate (Pi) medium for up to 7 days; calcium deposition was determined via Alizarin staining and colorimetric assay. Inflammatory factor secretion was evaluated via ELISA and JAK-STAT members' activation using Western blot or immunohistochemistry on HASMCs or calcified aortas of Vitamin D-treated C57BL6/J mice, respectively. The JAK-STAT pathway was blocked by JAK Inhibitor I and Von Kossa staining was used for calcium deposits in murine aortic rings. During Pi-induced calcification, HASMCs released IL-6, IL-8, and MCP-1 and activated JAK1-JAK3 proteins and STAT1. Phospho-STAT1 was detected in murine calcified aortas. Blocking of the JAK-STAT cascade reduced HASMC proliferation and pro-inflammatory factor expression and release while increasing calcium deposition and osteogenic transcription factor RUNX2 expression. Consistently, JAK-STAT pathway inhibition exacerbates mouse aortic ring calcification ex vivo. Intriguingly, our results suggest an alternative link between VSMC inflammation and VC.

Biologic Antiresorptive: Denosumab

Background

Osteoporosis is an age-related common bone disorder characterized by low bone mineral density and increased fragility fracture risk. Various Antiresorptive medications are being used to target osteoclast mediated bone resorption to prevent bone loss and reduce fracture risk.

About Denosumab

Denosumab is a novel biological antiresorptive drug that belongs to the class of monoclonal antibodies. It binds to and inhibits the cytokine receptor activator of nuclear factor kappa-B ligand (RANKL), which is requisite for osteoclast differentiation, function and survival.

Effectiveness

Denosumab has been shown to be a potent and effective therapy for osteoporosis, with clinical trial data demonstrating significant improvement in bone mineral density (BMD) and reductions in fracture risk at various skeletal sites for more than 10 years of treatment.

Safety Profile

Denosumab has a favourable benefit/risk profile, with low rates of complications such as infection, atypical femoral fracture and osteonecrosis of the jawbone.

Challenges

However, denosumab treatment requires continuous administration, as discontinuation leads to rapid bone mineral loss and increased risk of multiple vertebral fractures due to rebound of bone turnover. Therefore, modification to another anti-osteoporosis drug therapy after denosumab discontinuation is required to maintain bone health.

Conclusion

Denosumab is a promising biological antiresorptive therapy for osteoporosis that offers high efficacy and safety, but also poses challenges for long-term management.

Denosumab and Mortality in a Real-World Setting: A Comparative Study

Denosumab (Dmab) is increasingly prescribed worldwide. Unlike bisphosphonates (BPs), its effect on mortality has yet to be well explored. This study examined the association between Dmab and all-cause mortality compared with no treatment in subjects with a fracture and BPs in subjects without a fracture. The study population was from the Sax Institute's 45 and Up Study (n = 267,357), a prospective population-based cohort with questionnaire data linked to hospital admissions (Admitted Patients Data Collection [APDC] data were linked by the Centre for Health Record Linkage), medication records (Pharmaceutical Benefits Scheme [PBS] provided by Services Australia), and stored securely (secure data access was provided through the Sax Institute's Secure Unified Research Environment [SURE]). The new-user cohort design with propensity-score (PS) matching was implemented. In the fracture cohort, Dmab and oral BP users were matched 1:2 to no treatment (Dmab: 617 women, 154 men; oral BPs: 615 women, 266 men). In the no-fracture cohort, Dmab users were matched 1:1 with oral BPs and zoledronic acid (Zol) users (Dmab:oral BPs: 479 men, 1534 women; Dmab:Zol: 280 men, 625 women). Mortality risk was measured using sex-specific pairwise multivariable Cox models. In the fracture cohort, compared with no treatment, Dmab was associated with 48% lower mortality in women (hazard ratio [HR] = 0.52, 95% confidence interval [CI] 0.36-0.72) but not in men. Oral BPs were associated with 44% lower mortality in both sexes (women HR = 0.56, 95% CI 0.42-0.77; men HR = 0.56, 95% CI 0.40-0.78). In the no-fracture cohort, compared with BPs, Dmab was associated with 1.5- to 2.5-fold higher mortality than oral BPs (women HR = 1.49, 95% CI 1.13-1.98; men HR = 2.74; 95% CI 1.82-4.11) but similar mortality to Zol. Dmab in women and oral BPs were associated with lower post-fracture mortality than no treatment. However, Dmab users had generally higher mortality than oral BP users in those without fractures. © 2023 American Society for Bone and Mineral Research (ASBMR).