Search Results (471)

Background: We previously reported that knocking down the ubiquitin E3 ligase LNX2 in bone marrow monocytes by shRNAs attenuated osteoclastogenesis in vitro. However, the role of LNX2 in the regulation of osteoclasts and bone homeostasis in vivo remains unknown. Methods: In this study, we generated myeloid Lnx2 conditional knockout mice by crossing Lnx2-flox mice with LysM-Cre mice. The role of LNX2 was verified through in vitro osteoclast induction experiments using mononuclear macrophages and experiments on estrogen-deficient osteoporosis models. Results: Micro-CT and histological analysis unveiled that loss of Lnx2 in osteoclast precursor cells decreased osteoclast numbers and increased trabecular bone mass in mice. Moreover, Lnx2 deficiency prevented bone loss in an ovariectomized mouse model of postmenopausal osteoporosis. In vitro mechanistic studies identified that the loss of Lnx2 had little effect on cell proliferation but significantly inhibited the formation of osteoclasts and bone resorption. Furthermore, the deletion of Lnx2 decreased the expression of NOTCH2 and its downstream HES1 via enhancing the level of the NOTCH2 inhibitor, NUMB. Conclusions: Our findings elucidate an important role of Lnx2 in the regulation of osteoclasts and bone metabolism and indicate that Lnx2 is a potential therapeutic target for the treatment of osteoporosis. Full article

Osteoporosis in women is strongly influenced by menopause, a major physiological transition that reshapes bone metabolism. Although low bone mineral density (BMD) in premenopausal women and osteoporosis in postmenopausal women share the clinical outcome of skeletal fragility, it remains unclear whether they reflect a shared molecular program or distinct regulatory mechanisms. Here, we compared genetic signals associated with premenopausal and postmenopausal low BMD in Korean women using two independent genotyping platforms with distinct variant coverage. After allele harmonization and heterogeneity testing, variants were classified as reversal signals, showing directionally discordant effects across menopausal status, or stable signals, showing concordant effects. Gene-level association analysis was performed using Multi-marker Analysis of GenoMic Annotation (MAGMA), followed by functional enrichment and network-based analyses. Reversal and stable signals showed distinct biological patterns. Reversal signals consistently converged on cyclic nucleotide-related pathways, including cyclic adenosine monophosphate/cyclic guanosine monophosphate (cAMP/cGMP) signaling and nitric oxide-mediated processes, whereas stable signals were more broadly distributed across pathways related to ion homeostasis, cell–substrate adhesion, and structural maintenance. These pathway-level patterns were reproducible across platforms despite limited SNP-level overlap. These findings suggest that low BMD across the menopausal transition is better resolved at the gene and pathway levels than at the level of individual SNPs. Full article

Background: Postmenopausal osteoporosis is associated with cellular senescence and the accumulation of the senescence-associated secretory phenotype (SASP). While mesenchymal stem cell (MSC)-derived exosomes show tissue repair potential, the efficacy and mechanisms of MSC-derived apoptotic vesicles (apoVs) remain unclear. This study compared MSC-apoVs and exosomes in postmenopausal osteoporosis and investigated the underlying epigenetic mechanisms. Methods: Therapeutic efficacy was evaluated in an ovariectomized (OVX) mouse model and senescent human bone marrow mesenchymal stem cells (hBMMSCs). Small RNA sequencing identified differential microRNA (miRNA) cargos between vesicle types. SASP-related cytokine expression (IL-6, TNF-α, MCP-1) and pathway activation were assessed by RT-qPCR, ELISA, and Western blot. Results: MSC-apoV treatment attenuated bone loss in OVX mice and reduced SASP expression in senescent hBMMSCs to a greater extent than exosomes. Small RNA sequencing revealed that apoVs were enriched with a specific miRNA cluster, including hsa-let-7b-5p, hsa-miR-92a-3p, and hsa-miR-98-5p. Bioinformatic analyses identified BRAF and CRKL as downstream targets of this miRNA cluster, supported by reduced protein levels after apoV treatment. Subsequent molecular assays showed that apoV treatment inhibited the phosphorylation of both the MAPK (p38 and JNK) and NF-κB (p65) signaling pathways, which correlated with reduced local inflammation in the bone marrow microenvironment and preserved osteogenic differentiation capacity. Conclusions: MSC-apoVs attenuate postmenopausal osteoporosis more effectively than exosomes. This enhanced efficacy is associated with the delivery of an enriched miRNA cluster that inhibits MAPK and NF-κB signaling, together with suppression of BRAF and CRKL protein expression. ApoVs may represent a cell-free therapeutic strategy for age-related bone loss. Full article

Background: Osteoporosis is a major skeletal disorder, particularly affecting postmenopausal women. Young ovariectomized rat models are commonly used to investigate estrogen deficiency-related skeletal changes, although they do not fully reproduce osteoporosis in a mature postmenopausal skeleton. Established pharmacological therapies remain the cornerstone of osteoporosis management, while nutritional factors continue to be investigated for their potential supportive role in bone metabolism. Menaquinone-7 (MK-7), a form of vitamin K2, has been investigated for potential skeletal effects through vitamin k-dependent mechanisms, particularly osteocalcin carboxylation. The aim of this study was to evaluate the dose-dependent effects of MK-7 on bone turnover markers, femoral mechanical resistance, qualitative histological findings, and hepatic safety in a young ovariectomized rat model. Methods: Forty female Wistar rats that were 8 weeks old, and thus still undergoing skeletal maturation, were assigned to four groups: sham-operated controls, ovariectomized controls, ovariectomized rats treated with low-dose MK-7, and ovariectomized rats treated with high-dose MK-7. Treatment was administered every 48 h for 12 weeks. At study completion, 35 rats survived; standardized analysis included eight animals per group. Plasma bone turnover markers (BTMs) and alanine aminotransferase were measured, femoral strength was assessed by the three-point bending test, and bone and liver histology was analyzed. Results: Biomechanical testing showed that high-dose MK-7 was associated with greater femoral mechanical resistance compared with untreated ovariectomized rats, while qualitative histology suggested differences in cortical architecture among groups. Biochemically, MK-7 treatment reduced undercarboxylated osteocalcin, suggesting vitamin K-dependent target engagement, whereas conventional turnover markers showed discordant findings. Overall, hepatic architecture was preserved, although mild hepatocellular apoptosis was observed. Conclusions: In this young OVX rat model, high-dose MK-7 was associated with improved femoral mechanical resistance compared with untreated OVX controls. However, because ovariectomy was performed during skeletal maturation, these findings should be interpreted as preliminary and cannot be directly extrapolated to established postmenopausal osteoporosis in a mature skeleton, and further studies are needed to clarify its activity pathways and safety profile. Full article

Background: Postmenopausal osteoporosis is a common metabolic bone disorder characterized by decreased bone mass and microstructural deterioration, often accompanied by increased bone marrow adiposity and systemic fat accumulation. Kun-Ling Wan Formula (KLW) is a compound Chinese medicine clinically used for gynecological disorders, though its effects on postmenopausal osteoporosis and associated fat accumulation remain unclear. Distinct from previous herbal formulation studies that primarily focused on bone outcomes, our study uniquely integrates bone protection, marrow adiposity reduction, systemic metabolic improvement, and multi-omics mechanistic dissection in a high-fat diet-fed ovariectomized mouse model. Methods: KLW chemical composition was analyzed by UPLC-Q-TOF/MS. Ovariectomized (OVX) C57BL/6J mice fed high-fat or normal diet were treated with KLW at clinically equivalent or double doses, with estrogen and active compounds as controls. Bone microstructure was assessed by micro-CT, bone marrow fat by MRI-PDFF, and metabolism by OGTT, ITT, and metabolic cages. Network pharmacology, proteomics, molecular docking, and dynamics simulations identified core targets. C3H10T1/2 cells were used to assess osteogenic/adipogenic differentiation and mTOR pathway activation. Results: Twelve compounds were identified in KLW. In OVX mice, KLW significantly improved bone mineral density and trabecular microstructure, reduced adiposity and bone marrow fat, and enhanced glucose tolerance and insulin sensitivity. In vitro, KLW promoted osteogenesis and suppressed adipogenesis in C3H10T1/2 cells. Integrative analyses identified mTOR as a central target, with chrysophanol, pyrogallol, and apigenin showing high-affinity binding. KLW inhibited mTOR/S6K phosphorylation during differentiation, an effect reversible by leucine. Conclusions: KLW ameliorates osteoporosis and reduces fat accumulation in OVX mice by shifting mesenchymal stem cell differentiation toward osteogenesis via mTOR pathway modulation. Full article

Background: Postmenopausal osteoporosis (PMOP) is a common metabolic bone disorder characterized by disrupted bone remodeling due to estrogen deficiency. Erxian Decoction (EXD), a traditional Chinese medicine formula, has shown clinical efficacy against PMOP, but its bioactive constituents and molecular mechanisms remain elusive. Methods: The therapeutic effects of EXD were evaluated in ovariectomized (OVX) mice using micro-CT and bone histomorphometry. Absorbed constituents of EXD were identified by UHPLC-Q analysis. Network pharmacology and quantitative proteomics were integrated to predict the key pathways and targets. The candidate target was validated by in vivo assays, including Western blot, glutathione (GSH) levels, glutathione S-transferases (GSTs) activity, malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE) levels. Molecular docking was performed to assess the binding affinity between bioactive components and the target protein. Results: EXD treatment significantly ameliorated bone microarchitecture deterioration and restored bone remodeling balance in OVX mice. A total of 137 core absorbed constituents of EXD were identified. Integrated network pharmacology and proteomics analyses revealed that EXD primarily modulates the glutathione metabolism pathway to counteract oxidative stress. Glutathione S-transferase A1 (GSTA1) was pinpointed as a potential target. In vivo experiments confirmed that EXD upregulated GSTA1 expression, restored total GSTs activity, replenished GSH reserves, and reduced MDA and 4-HNE levels. Molecular docking demonstrated stable protein–ligand interactions between bioactive components of EXD and GSTA1. Conclusions: EXD alleviates PMOP by activating GSTA1-mediated glutathione metabolism and suppressing oxidative stress. These findings provide a mechanistic basis for the clinical application of EXD in treating PMOP. Full article

Background: Osteoporosis has a rising global incidence and social burden. Serum uric acid’s dual roles in oxidative stress and inflammation may influence bone health, but findings are inconsistent and require further research. This study aimed to evaluate the relationship between SUA levels and osteoporosis in a multicenter cohort obtained from different regions of Türkiye. Methods: This multi-center retrospective study included 3280 individuals, postmenopausal women and men aged 45 and older, from 16 centers in Türkiye. Individuals were excluded if they recently consumed alcohol, had severe renal dysfunction, certain hormonal or mineral disorders, specific medications, or certain menopausal statuses. Bone mineral density (BMD) at the hip and lumbar spine was measured using dual-energy X-ray absorptiometry (DXA), and participants were classified as normal or having osteopenia or osteoporosis based on T-score thresholds. Results: Overall, 34.8% were male, and 65.2% were female. For the lumbar spine, 36.8% had osteopenia, and 13.5% had osteoporosis; similarly, for the total hip, 40.8% had osteopenia, and 7.9% had osteoporosis. ROC analysis identified a threshold of 3.9 mg/dL serum uric acid (SUA) (AUC 0.374; p < 0.001), which was positively associated with both lumbar and total hip BMD. Osteoporosis rates were higher in patients with SUA < 3.9 mg/dL compared to those with SUA ≥ 3.9 mg/dL at the lumbar spine (29.1% vs. 14.2%, p < 0.001) and total hip sites (23.6% vs. 15.9%, p = 0.003). After adjustment for potential confounders, SUA was a significant independent predictor of osteoporosis in the lumbar spine (OR 0.70; p < 0.001) and the hip (OR 0.80; p < 0.001). Conclusions: Serum uric acid levels are inversely linked to bone mineral density and osteoporosis risk, indicating a potential role in bone health. However, due to study limitations, causal relationships remain unproven, and further research is needed. Full article

Background: This study aimed to determine whether osteoporosis is associated with differences in the subgingival microbiome of postmenopausal women, stratified by periodontitis stage. Methods: In this observational, stratified case–control study, 166 postmenopausal women were assigned to six strata defined by bone status (osteoporosis vs. normal BMD) and periodontal category (no periodontitis, Stage I–II, Stage III–IV). Standardized pooled subgingival samples were profiled by 16S rRNA gene sequencing. Community structure was evaluated using Bray–Curtis dissimilarity and tested with PERMANOVA (9999 permutations) and prespecified contrasts comparing osteoporosis versus normal BMD within each periodontal category (Holm adjustment). Alpha diversity (Shannon) was assessed using two-way ANOVA. Results: Periodontal category was strongly associated with community structure (PERMANOVA R² = 0.514, pseudo-F = 86.681, p < 0.0001), whereas bone status (R² = 0.004, p = 0.178) and the bone status × periodontal category interaction (R² = 0.007, p = 0.294) were not. None of the three prespecified within-category contrasts reached significance after Holm adjustment. Shannon diversity differed by periodontal category (p = 1.93 × 10⁻²⁴) but not by bone status (p = 0.200), with similar distributions between osteoporosis and normal BMD within each periodontal category. Conclusions: In postmenopausal women, periodontitis severity dominates variation in the subgingival microbiome, and osteoporosis does not confer an additional community-level or taxonomic signature when periodontal status is held constant. Longitudinal and multi-omic studies incorporating host-response biomarkers and therapy exposures are warranted to clarify whether osteoporosis influences periodontal susceptibility and progression primarily through host-mediated mechanisms. Full article

Background and Objectives: Individuals classified as having very high fracture risk remain vulnerable to imminent fractures even when treated with antiresorptive therapies. This meta-analysis evaluated whether initiating treatment with anabolic agents, including teriparatide, abaloparatide, and romosozumab, provides superior fracture protection in this high-risk population. Materials and Methods: A systematic review and meta-analysis of randomized controlled trials was conducted following PRISMA standards. Eligible studies included adults at very high fracture risk, defined by recent or multiple fragility fractures or markedly low bone mineral density, who received anabolic therapy as initial treatment compared with placebo or antiresorptive agents. Outcomes of interest were new vertebral, non-vertebral, hip, and clinical fractures. Effect estimates were pooled using random-effects models. Results: Six randomized trials encompassing 17,872 participants were analyzed. Initiation with anabolic therapy was associated with a marked reduction in incident vertebral fractures. The labeled pooled summary estimate for vertebral fractures was 0.43 (95% confidence interval 0.34–0.54). Significant risk reductions were also observed for clinical fractures (hazard ratio 0.62, 95% confidence interval 0.51–0.75), non-vertebral fractures (pooled effect estimate 0.71, 95% confidence interval 0.59–0.85), and hip fractures (risk ratio 0.65, 95% confidence interval 0.45–0.96). Exploratory subgroup analyses suggested greater vertebral fracture protection versus placebo and persistent benefit versus active antiresorptive comparators. Sequential therapy using an anabolic agent followed by an antiresorptive reduced spinal fracture risk by approximately half. Considerable heterogeneity was noted for vertebral fracture outcomes. Conclusions: Starting osteoporosis treatment with anabolic agents results in faster and more-pronounced fracture risk reduction across all major fracture categories in patients at very high fracture risk. These findings support a shift toward anabolic-first treatment sequencing in this particularly vulnerable group. Full article

Postmenopausal osteoporosis is an age-related condition in which estrogen deficiency drives low-grade inflammation and oxidative stress, disrupting the homeostatic balance between bone formation and resorption. Since osteopenia represents a critical intermediate stage, preventive strategies are essential to mitigate its progression. Preclinical studies suggest that hydrogen sulfide (H₂S), a gaseous mediator with antioxidant properties, protects bone metabolism by supporting osteoblast function and suppressing osteoclast activity. Building on this evidence, we conducted the first exploratory clinical trial assessing the effects of inhalation therapy with sulfurous mineral waters on systemic biomarkers in postmenopausal women with osteopenia. Thirty-eight eligible participants underwent a daily inhalation of sulfurous waters (14.6 mg/L sulfide) for 12 consecutive days. Biomarkers of oxidative stress, inflammation, and bone turnover were assessed at baseline, immediately post-treatment, and five days after cessation in the serum of patients. The treatment was well tolerated and did not cause any early adverse effect. Serum H₂S levels, measured in a subset of participants, significantly increased, confirming systemic bioavailability. Sulfurous water inhalation induced a marked change in oxidative stress, with malondialdehyde levels declining by up to 37% from baseline. Pro-inflammatory cytokines, particularly IL-8 and MIP-1α, were significantly decreased (up to 50–70%) at the end of the treatment. Reference bone turnover markers P1NP and CTX-1 did not show significant changes; however, BALP exhibited a significant increase, suggesting the activation of pathways linked to biomineralization. These findings provide preliminary human evidence that inhaled sulfurous waters enhance systemic H₂S bioavailability and modulate redox and inflammatory pathways associated with bone remodeling in osteopenic women, supporting the rationale for further controlled pharmacodynamic investigations evaluating the potential of H₂S in bone health. Full article

The global prevalence of osteoporosis is rising, particularly among the elderly and post-menopausal population. Although natural flavonoids can inhibit osteoclast overactivation, their low abundance and extraction challenges limit clinical translation. In this study, we synthesized a flavonoid derivative, SZQ-4, and evaluated its therapeutic potential for post-menopausal osteoporosis (PMO). Using an RANKL-induced osteoclastogenesis model in vitro, we demonstrated through TRAP staining, RT-qPCR, and bone resorption assays that SZQ-4 significantly suppresses osteoclast formation and activity. Mechanistically, RNA-seq, Western blot, siRNA knockdown, and plasmid-based overexpression experiments revealed that SZQ-4 reduces RANKL-induced reactive oxygen species (ROS) production, regulates SIRT3 expression, and improves mitochondrial function, thereby attenuating osteoclast differentiation. In an ovariectomy-induced bone loss mouse model, SZQ-4 treatment markedly alleviated femoral bone loss, decreased osteoclast numbers, and lowered ROS levels in the bone marrow microenvironment. Collectively, our findings indicate that SZQ-4 inhibits osteoclast-driven bone resorption by modulating the ROS-SIRT3–mitochondrial function axis, highlighting its potential as a candidate for preventing pathological bone loss. Full article

Background/Objectives: Vitamin D plays a central role in calcium and bone homeostasis; however, evidence linking serum 25-hydroxyvitamin D (25(OH)D) to bone mineral density (BMD) in postmenopausal women remains inconsistent. Because body weight and lean mass strongly influence skeletal loading and may also affect circulating 25(OH)D, we aimed to evaluate the association between serum 25(OH)D and bone outcomes in early postmenopausal women and to determine whether body composition attenuates this relationship. Methods: In this cross-sectional study, 120 women within 10 years after natural menopause (59.5 ± 6.3 years) were assessed. Serum 25(OH)D was measured by chemiluminescent immunoassay. Total body areal bone mineral density (total body aBMD, g/cm²) was assessed by DXA, and trabecular volumetric BMD and cortical thickness were obtained using 3D modeling. Associations were examined using Spearman correlations and multivariable linear and logistic regression models adjusted for age, body weight, lean mass, and years since menopause. Results: Median serum 25(OH)D was 23.7 ng/mL [16.7–30.4]. A modest correlation was observed between 25(OH)D and total body aBMD (ρ = 0.22, p = 0.016), but not with trabecular volumetric BMD or cortical thickness. After adjustment, 25(OH)D was not independently associated with total body aBMD (p = 0.144), whereas body weight remained significantly associated (β = 0.27, p = 0.002). In logistic models, body weight (OR = 0.93, 95% CI 0.90–0.96) and lean mass (OR = 0.97, 95% CI 0.95–0.99) were protective against low BMD, while the association with 25(OH)D was modest. Conclusions: In early postmenopause, the association between serum 25(OH)D and BMD is modest and largely attenuated after accounting for body composition. Body weight and lean mass appear to be stronger determinants of bone outcomes than vitamin D status. Full article

Background/Objective: Periodontitis and osteoporosis frequently co-occur after menopause, yet the immune–bone pathways linking oral and skeletal phenotypes remain incompletely defined. This study investigated whether periodontitis severity and low bone mineral density (BMD) in postmenopausal women are associated with convergent systemic inflammaging and immunosenescence phenotypes and with a salivary RANKL/OPG imbalance. Methods: In this cross-sectional study, 280 postmenopausal women were assigned to a 2 × 2 factorial design based on periodontal status (severe vs. no/mild) and BMD status (low vs. normal; DXA T-score). Full-mouth periodontal measurements (PD, CAL, BOP, plaque index, tooth count; stage/grade) were recorded. Salivary RANKL and OPG were quantified, and the RANKL/OPG ratio was calculated. Systemic inflammaging markers (hs-CRP, IL-6, TNF-α) and CMV IgG were assessed, and T-cell immune-aging phenotypes were profiled by flow cytometry (CD3, CD4, CD8, CD45RA, CCR7, CD28, CD57, KLRG1, PD-1, CD27). Results: Severe periodontitis and low BMD were each associated with higher salivary RANKL/OPG ratios and greater systemic inflammatory burden, with modest interaction effects. Immune-aging profiles showed higher proportions of late-differentiated CD8+ phenotypes, and CMV seropositivity was strongly associated with immunosenescence markers. Conclusions: In postmenopausal women, periodontal destruction and low BMD were aligned with osteoclastogenic and immune-aging signatures, consistent with oral–skeletal immune crosstalk. Findings should be interpreted as associative rather than causal, and longitudinal observational studies are warranted to clarify temporality. Full article

Background/Objectives: To assess the clinical similarity in terms of efficacy, pharmacodynamics (PD), pharmacokinetics (PK), safety, and immunogenicity between MB09 (denosumab biosimilar) and the reference product [RP, (Prolia^®)] up to 18 months in women with postmenopausal osteoporosis (PMO). Methods: Women with PMO received three doses of 60 mg of MB09 or RP subcutaneously, every 6 months [two doses in the main treatment period and one dose in the transition period (TP)]. The primary efficacy endpoint was the percent change from baseline (%CfB) in lumbar spine bone mineral density (BMD). Secondary endpoints included other efficacy parameters and PD, PK, safety, and immunogenicity assessments. Results: A total of 555 subjects received MB09 (N = 278) or RP (N = 277). At month 12, %CfB in lumbar spine BMD was comparable between groups (MB09 versus Prolia) and met the predefined equivalence margins. Secondary efficacy endpoints—%CfB in lumbar spine BMD at 6 months and %CfB in hip and femoral neck BMD at 6 and 12 months—were similar between groups. PD marker (serum carboxy terminal cross linking telopeptide of type I collagen) was similarly suppressed in both groups, and the inhibition was maintained in the TP. PK results showed similar denosumab systemic exposure for MB09 and the RP. Both study treatments were well tolerated with similar safety profiles throughout the study period. The incidence of anti-denosumab antibodies was very low. Conclusions: MB09 demonstrated equivalent efficacy to the reference denosumab in women with PMO. All secondary efficacy endpoints, together with PD, PK, safety, and immunogenicity assessments, supported MB09 as a denosumab biosimilar (NCT05338086, EudraCT No. 2021-003609-24). Full article

Background/Objectives: Systemic sclerosis (SSc) patients frequently develop osteoporosis; however, vertebral fracture risk factors remain poorly characterized. This study identifies general and SSc-specific predictors of vertebral fractures in SSc patients undergoing osteoporosis evaluation. Methods: This multicenter cross-sectional study enrolled consecutive SSc patients meeting ACR/EULAR 2013 criteria with suspected osteoporosis. Data included demographics, disease characteristics, bone density (DXA), and vertebral imaging. Stepwise logistic regression analyzed fracture associations (p ≤ 0.05 significant). Results: The majority of 103 enrolled patients were female and all were post-menopausal. The prevalence of osteoporosis was 52.4%, that of vertebral fractures was 38.8%, and that of osteopenia was 28.1%. General risk factor analysis identified family history of fragility fractures (OR 11.8, p = 0.008) and vertebral T-scores (OR 0.6, p = 0.049) as significant predictors. When adding SSc-specific factors, only family history (OR 13.8, p = 0.03) and gastrointestinal (GI) involvement (OR 4.8, p = 0.05) remained significant. Conclusions: Vertebral fractures in SSc patients are strongly linked to a family history of fractures. The suggestive association with GI involvement may imply a significant role for malabsorption-related metabolic impairment. Prioritizing bone density screening in SSc patients with GI symptoms may enable earlier intervention and reduce fracture risk. Full article