Osteoprotegerin Research Articles

This study aims to evaluate and compare the effectiveness of 1% melatonin gel combined with demineralized freeze-dried bone allograft (DFDBA) versus DFDBA alone in treating intrabony periodontal defects in Stage II & III periodontitis. Clinical and radiographic outcomes were assessed using cone-beam computed tomography (CBCT), along with analysis of gingival crevicular fluid (GCF) levels of receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG). A prospective, randomized, controlled, single-blinded clinical trial was conducted on 20 patients with 20 intrabony defects. The control group received DFDBA alone, while the test group received a combination of 1% melatonin gel and DFDBA. Clinical parameters Clinical Attachment Level (CAL) and Probing Pocket Depth (PPD) were evaluated at baseline, 3, and 6 months. Using cone beam computed tomography (CBCT) radiographic parameters linear bone fill and bone volume and GCF biomarkers (RANKL and OPG) were assessed at baseline and 6 months. Plaque Index (PI) and Sulcus Bleeding Index (SBI) were secondary outcomes. CAL change served as the primary outcome variable. After 6 months, the test group showed a mean CAL gain of 3.10 ± 0.87 mm and the control group 4.00 ± 1.85 mm, which was not statistically significant between the groups; however, intra-group comparison revealed a statistically significant CAL gain from baseline in both groups. Both groups showed improvements in assessed parameters, however, the test group demonstrated significantly greater bone fill (1.88 ± 0.26 mm vs. 1.16 ± 0.38 mm) and bone volume gain (22.67 ± 1.36 mm³ vs. 14.78 ± 0.5 mm³; p< 0.000). Greater reduction in PPD and gain in CAL were noted in the test group. GCF analysis revealed a significant increase in OPG (99.87 ± 15.07) and reduction in RANKL levels (66.13 ± 19.12) in the test group at 6 months (p= 0.000). Melatonin gel as an adjunct to DFDBA enhances clinical, radiographic, and biochemical outcomes in intrabony periodontal defect therapy. Clinical Trials Registry of India (CTRI/2023/07/055039).

Relevance. Evaluation of mineral metabolism markers in mixed saliva may be a non-invasive method for diagnosing potential disorders and developing strategies for the prevention and treatment of dental diseases in children with hypophosphatasia (HPP). Objective: To determine the content of vitamin D, osteocalcin (OCC), osteoprotegerin (OPT), bone-specific alkaline phosphatase (BSAP), and parathyroid hormone (PTH) in mixed saliva and to study their relationships with some clinical parameters of dental status in children with HPP. Materials and Methods. Twenty children with HPP, aged 6–17 years, and 20 healthy children of the same age were examined. Caries intensity and structural and functional caries resistance of enamel in permanent teeth were assessed using the KPU index and the TER test, respectively; periodontal tissue condition was determined using the PMA index. The content of vitamin D, TBPC, OPT, and IAP were determined using enzyme-linked immunosorbent assay (ELISA). Results. Clinical evaluation of key dental parameters in children with HPP and healthy children revealed insufficient oral hygiene associated with an increase in caries in permanent teeth and the presence of moderate gingivitis. In the laboratory phase of the study, a statistically significant difference (2-fold) in the mixed saliva of children with HPP was found in a two-fold decrease in IAP secretion. Reduced levels of vitamin D concentration and OPT minute secretion in mixed saliva in children with HPP are associated with the development of caries in permanent teeth and soft tissue inflammation. Conclusions. The identified changes in biochemical parameters (IBP, vitamin D, OPT, and OPT) in mixed saliva allow us to recommend them as markers for identifying the risk of impaired formation and mineralization of dental and periodontal tissues in children with hypophosphatasia.

BACKGROUNDSteroid-induced avascular necrosis of the femoral head (SANFH) involves bone metabolism imbalance and lacks effective therapies. Mesenchymal stem cells (MSCs), particularly human umbilical cord MSCs (hUCMSCs), offer promise due to their osteogenic and immunomodulatory potential. Sclerostin (SOST) inhibits bone formation, so we developed a multi-target gene silencing strategy against SOST using RNA interference. We created hUCMSCs with SOST-silenced (sh-hUCMSCs) and compared their therapeutic efficacy with unmodified hUCMSCs in SANFH mice. This study explores a novel approach to enhance osteogenesis and mitigate SANFH progression.AIMTo assess the effects of sh-hUCMSCs on bone metabolism in SANFH.METHODShUCMSCs were isolated from placental tissue and transfected with SOST-targeting short hairpin RNA plasmids. A SANFH mouse model was established through intraperitoneal injection of lipopolysaccharide (20 μg/kg) followed by intramuscular methylprednisolone administration (40 mg/kg). Mice were randomized into four experimental groups (n = 10/group): Sham control, SANFH (untreated), hUCMSCs-treated, and sh-hUCMSCs-treated. Micro-computed tomography was used to measure bone volume (BV), bone surface area, bone surface/BV ratio, trabecular number, trabecular thickness, and trabecular separation. Quantification of adipocyte area by hematoxylin and eosin staining. Collagen fiber volume was assessed by Masson’s trichrome staining. Serum levels of osteoprotegerin (OPG), receptor activator of nuclear factor kappa B (RANK), RANK ligand (RANKL), tartrate-resistant acid phosphatase, and the OPG/RANKL ratio were measured by enzyme-linked immunosorbent assay. The expression levels of alkaline phosphatase, OPG, SOST, β-catenin, peroxisome proliferator-activated receptor gamma, and CCAAT/enhancer-binding protein in bone tissue were determined by western blot analysis.RESULTShUCMSCs and sh-hUCMSCs exhibited typical fibroblast-like morphology and high expression of MSC surface markers (CD90, CD73, CD105 > 98%). These cells demonstrated tri-lineage differentiation potential, confirmed by positive Alizarin Red S, Oil Red O, and Alcian Blue staining, and upregulation of lineage-specific genes. After SOST-RNA interference modification, sh-hUCMSCs showed enhanced inhibition of adipogenesis and improved bone formation in a rat model of SANFH. Histological analysis revealed reduced lipid infiltration and empty lacunae in the femoral head of the sh-hUCMSC group. Western blot showed decreased CCAAT/enhancer-binding protein and peroxisome proliferator-activated receptor gamma expression (P < 0.05). Masson staining and micro-computed tomography analysis confirmed significantly increased BV, trabecular number, trabecular thickness, and reduced trabecular separation in the sh-hUCMSC group compared to unmodified MSCs and SANFH groups (P < 0.05). Serum enzyme-linked immunosorbent assay showed higher OPG and lower RANK, RANKL, and tartrate-resistant acid phosphatase levels in the sh-hUCMSCs group. Western blot further confirmed upregulated alkaline phosphatase, OPG, β-catenin, and downregulated SOST expression in sh-hUCMSCs compared to controls (P < 0.05). These results suggest that SOST inhibition enhances the osteogenic potential and therapeutic efficacy of hUCMSCs in SANFH.CONCLUSIONsh-hUCMSCs alleviate SANFH by activating the Wnt/β-catenin signaling pathway, thereby promoting osteogenic differentiation and suppressing adipogenesis to restore bone metabolic balance.

BackgroundOlder individuals are at high risk for severe COVID-19 and often experience geriatric syndromes as post-COVID-19 sequelae associated with inflammation. Osteoprotegerin (OPG) and Tumor Necrosis Factor Receptor 1 (TNFR1) are emerging as promising biomarkers in inflammation-associated diseases. Here, these and other members of the tumor necrosis factor superfamily (TNFSF) were investigated as potential biomarkers to monitor older adults during acute COVID-19 and post-COVID-19 recovery.Patients and MethodsThis study included 75 patients with acute COVID-19, 26 post-COVID-19 (evaluated at 4 and 12 months), 35 healthy donors (HD), and 36 individuals with interstitial lung diseases (ILD), all aged over 60. Plasma levels of 14 soluble TNFSF members were measured using flow cytometry-based multiplex immunoassays and ELISA. Multiple logistic regression and ROC curve analyses were performed to assess the potential of TNFSF members as biomarkers.ResultsFlow cytometry revealed significantly higher levels of OPG, BAFF, and APRIL in acute COVID-19 patients than in HD and ILD (p<0.001). Through an ELISA, high levels of OPG (p<0.0001), APRIL (p<0.05), and BAFF (p<0.0001) were confirmed, and TNFR1 (p<0.0001) was also revealed. In this pilot study, OPG and TNFR1 had AUCs >0.90 and were predictive of COVID-19, independent of comorbidities, while BAFF levels were modified by diabetes. Persistently elevated OPG and TNFR1 levels were also observed in post-COVID-19 patients at 4 and 12 months. Notably, OPG levels were higher in frail versus non-frail individuals at both time points (p<0.05), while TNFR1 levels were higher only at 4 months (p<0.05).ConclusionThis evidence indicates that OPG and TNFR1 are potential biomarkers of inflammation during acute COVID-19 and post-COVID-19 among older, mainly frail adults. These findings support their utility in managing post-COVID-19 geriatric frailty syndrome.

Disclosure: S.M. Cohen: None. J. Sun: None. F.J. Palella: None. J.E. Lake: None. S.L. Koletar: None. N.L. Haw: None. R.D. Ross: None. T.T. Brown: None.Background: People living with HIV (PLWH) experience higher rates of osteoporosis and fractures as they age compared to the general population, though mechanisms connecting HIV to bone loss remain incompletely understood. It is thought that HIV-related chronic inflammation alters bone metabolism—potentially via sclerostin/Wnt/β-catenin signaling, which regulates bone formation, or the RANK-RANK ligand (RANKL)/osteoprotegerin (OPG) axis, which regulates bone resorption. We hypothesized that sclerostin, OPG, and RANKL levels would be altered in PLWH and associated with BMD, inflammation, and HIV-specific factors. Methods: In a sub-study of the Multicenter AIDS Cohort Study, we enrolled 204 men with HIV on antiretroviral therapy (ART) and 204 men without HIV, all aged 50-69 years. Participants underwent dual-energy X-ray absorptiometry (DXA) scans at the lumbar spine (LS), total hip (TH), and femoral neck (FN), morning phlebotomy, and a detailed assessment of osteoporosis risk factors. We used the Wilcoxon Rank-Sum test to compare the two groups and multivariable linear regression to determine associations of sclerostin, OPG, and RANKL concentrations with 1) BMD, 2) inflammatory markers, and 3) HIV-1 viral load and nadir CD4+ count among PLWH. We adjusted for HIV and hepatitis C virus serostatus, demographic and behavioral covariates, osteoporosis risk factors, and ART types. Results: The median age was 60 years and median BMI was 25.3 kg/m2; these were similar by HIV serostatus. Men who were PLWH had significantly lower TH BMD (p=0.03), but LS and FN BMD did not differ between the two groups (LS p=0.86, FN p=0.30). PLWH had higher plasma OPG concentrations (p=0.03), lower RANKL concentrations (p=0.001), and higher soluble TNF-α receptor (sTNF-R) 1 and 2 concentrations (sTNF-R1 p=0.01, sTNF-R2 p<0.001). OPG and RANKL concentrations were both were positively associated with sTNF-R concentrations (OPG vs. sTNF-R1 p<0.001, OPG vs. sTNF-R2 p=0.003, RANKL vs. sTNF-R1 p=0.001, RANKL vs. sTNF-R2 p=0.002). However, OPG and RANKL concentrations were not associated with BMD. Sclerostin concentrations were not associated with sTNF-R concentrations, but lower sclerostin concentrations were associated with lower BMD at all sites regardless of HIV serostatus (LS p<0.001, TH p<0.001, FN p<0.001). Conclusion: Sclerostin concentrations were associated with BMD in men with and without HIV, which suggests that sclerostin is a marker of bone mass and osteocyte number. Circulating concentrations of OPG and RANKL were associated with HIV serostatus and systemic inflammation, but not with bone mineral density, among men with or at risk for HIV. These findings suggest that immune dysfunction in PLWH contributes to dysregulation of the RANK-RANKL/OPG axis, but these changes are not associated with changes in bone mass.Presentation: Saturday, July 12, 2025

The investigation of genetic factors influencing peri-implant diseases, particularly peri-implantitis (PI), offers insights into the complex interplay between host genetics and inflammatory responses within oral tissues. Numerous genes encoding cytokines, receptors, and regulatory proteins have been scrutinized for their roles in modulating immune responses and tissue homeostasis around dental implants. Notably, polymorphisms in genes encoding interleukins (IL-1, IL-6, IL-17, IL-10), tumor necrosis factor-alpha (TNF-α), and matrix metalloproteinases (MMPs) have emerged as potential genetic markers for susceptibility to peri-implant diseases. Additionally, genes involved in bone metabolism, such as osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANK-L), bone morphogenetic proteins (BMPs), and fibroblast growth factors (FGFs), contribute to peri-implant diseases. Polymorphisms in these genes affect bone resorption and regeneration processes, influencing the stability of dental implants. Variations in these genes can either enhance or hinder bone regeneration, impacting the healing process and the long-term success of implants. Moreover, investigations into less-studied genes like cluster of differentiation 14 (CD14), Chemokine Receptor 2 (CXCR2), and Fragment crystallizable gamma receptor (FcγRs) have revealed additional genetic determinants implicated in the pathogenesis of peri-implant diseases. These genes can influence immune cell function and inflammatory signaling pathways, contributing to the body's response to bacterial biofilms and other factors that compromise implant health. The study of these genetic variations provides a deeper understanding of individual susceptibility to PI and may guide personalized treatment strategies, ultimately improving implant success rate. Keywords: Peri-implantitis, polymorphism, immunity

The aim was to assess the impact of glucagon-like peptide-1 receptor agonists (GLP-1 RA) treatment on the progression of ascending aorta dilatation in patients with type 2 diabetes mellitus (T2DM). A total of 127 T2DM patients with subclinical ascending aortic dilatation (35–45 mm) were prospectively enrolled. Fifty-seven initiated GLP-1 RA therapy (liraglutide, semaglutide, or dulaglutide), while 70 continued on standard care. Ascending aortic diameter was measured by computed tomography angiography (CTA) at baseline and 24 months, alongside circulating markers of vascular remodeling: matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinases-1 (TIMP-1), C-reactive protein (CRP), and osteoprotegerin (OPG). Progression of aortic dilatation was significantly lower in the GLP-1 RA group compared with controls (+0.36 ± 0.20 mm vs. +1.05 ± 0.28 mm; p < 0.001). Therapy correlated with decreased MMP-9 and CRP (p < 0.01) and increased TIMP-1 and OPG (p < 0.05). The use of GLP-1 RA was an independent predictor of low progression, even in multivariate models after adjusting for demographic, metabolic, and biomarker data. GLP-1 RA therapy was associated with reduced progression of ascending aortic dilatation in T2DM, supporting a potential vasoprotective role beyond glucose lowering.

ABSTRACTRecent advancements in therapeutics have extended lifespan and improved neurodevelopmental outcomes in spinal muscular atrophy (SMA) patients, particularly with severe phenotypes. However, most patients fail to achieve normal motor function. Although structural bone defects and increased fracture susceptibility have been reported in both SMA patients and mouse models, the role of survival motor neuron (SMN) protein in bone homeostasis and therapeutic targets remains incompletely understood. To investigate the function of SMN in bone metabolism, a mild SMA mouse model and Smn1 conditional knockout mice in the myeloid lineage and mature osteoclasts were utilized. Bone architecture was assessed using micro‐computed tomography (micro‐CT), histological staining, and immunohistochemistry. RNA sequencing was performed to explore molecular mechanisms underlying skeletal defects. Primary bone marrow mesenchymal stem cells (BMSCs) and bone marrow‐derived macrophages (BMMs) were differentiated into osteoblasts and osteoclasts, respectively, and co‐cultured to evaluate SMN‐dependent regulation of osteoblast–osteoclast interactions. The therapeutic potential of exogenous osteoprotegerin (OPG) administration was further assessed. SMA mice exhibited significant bone mass reduction, characterized by impaired osteogenesis and increased osteoclastogenesis. However, in vitro experiments revealed suppressed osteoclast differentiation in BMMs from SMA mice, which was inconsistent with in vivo findings. Co‐culture studies demonstrated that osteoclast hyperactivity in SMA mice resulted from decreased osteoblast‐derived OPG, induced by local insulin‐like growth factor 1 (IGF1) deficiency. Mechanistically, SMN depletion led to IGF1 downregulation, thereby suppressing PI3K‐Akt signaling, reducing OPG expression, and ultimately disrupting osteoblast–osteoclast coupling. Administration of exogenous OPG effectively mitigated osteoclast differentiation and resorptive activity, indirectly promoting osteoblast function and partially restoring bone formation. These findings reveal that SMN protein loss caused IGF1 deficiency that inhibited the PI3K‐Akt signaling pathway, leading to downregulation of OPG expression and disrupted osteoblast–osteoclast coupling. This study highlights the therapeutic potential of targeting OPG in SMA to alleviate skeletal complications and improve patient outcomes.

Dioscoreae Rhizoma (DR) is a plant recognized for its dual medicinal and edible applications, exhibiting notable therapeutic efficacy, particularly in the treatment of postmenopausal osteoporosis (PMOP) associated with estrogen deficiency. This study sought to systematically identify bioactive compounds present in DR that interact with estrogen receptor β (ESR2) and employ affinity ultrafiltration in conjunction with UPLC-QE-Orbitrap-MS to find possible therapy options for PMOP. In this study, a C18 column was employed to fractionate the DR extract into distinct fractions, and the optimal active site in DR was identified based on its osteoprotegerin (OPG) content in MC3T3-E1 cells. To identify the DR components exhibiting high binding affinity for ESR2, affinity ultrafiltration coupled with UPLC-QE-Orbitrap-MS was utilized. These findings were further corroborated through molecular docking and molecular dynamics simulations. To further validate the osteogenic effects of the identified compounds, CCK-8 proliferation assays, along with OPG and alkaline phosphatase (ALP) activity assays, were employed. The 30% DR fraction demonstrated significant anti-PMOP activity. Acacetin, Adenosine, and Procyanidin B2 are recognized as the principal active constituents responsible for the anti-PMOP effects of DR. This study introduces a comprehensive approach combining affinity ultrafiltration with UPLC-QE-Orbitrap-MS and molecular docking to efficiently identify ESR2-targeted therapeutic compounds for PMOP in DR. The findings offer both theoretical and empirical foundations for the advancement of novel therapeutic strategies for PMOP.

Objective: To analyze the differential expression of inflammatory proteins in the tear fluid of patients with polypoidal choroidal vasculopathy (PCV) or neovascular age-related macular degeneration (nAMD). Methods: A total of 19 patients with PCV, 17 patients with nAMD, and 18 normal controls (NC) aged ≥50 years were enrolled. Tear samples were collected, and the expression levels of 92 inflammatory proteins were quantified using Olink technology. Differentially expressed proteins (DEPs) among the groups were analyzed, with particular attention to consistency with previous findings from aqueous humor studies. Results: Olink analysis revealed extensive DEPs among PCV, nAMD, and NC groups. Compared with NC, the PCV group exhibited significant upregulation of VEGFA, Interleukin (IL) -18, IL-1α, IL-8, IL-7, Monocyte chemotactic protein (MCP)-2, and Neurturin (NRTN), along with downregulation of Tumor necrosis factor (TNF) and IL-10. The nAMD group showed a more pronounced pro-inflammatory profile, with upregulation of VEGFA, IL-18, IL-8, IL-1α, IL-7, Fibroblast growth factor (FGF)-19, MCP-1, Matrix metalloproteinase (MMP)-10, NRTN, Stem cell factor (SCF), Osteoprotegerin (OPG), Eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), MMP-1, MCP-2, Fms-related tyrosine kinase 3 ligand (Flt3L), Tumor Necrosis Factor - like Weak Inducer of Apoptosis (TWEAK), Caspase (CASP)-8, and Tumor necrosis factor receptor superfamily member 9 (TNFRSF9), and downregulation of IL-10 and IL-12β. Comparison between PCV and nAMD indicated that IL-12β and Hepatocyte growth factor (HGF) were specifically upregulated in PCV, whereas SCF, VEGFA, Flt3L, OPG, MCP-1, T-cell surface glycoprotein CD8α (CD8α), Cystatin D (CST5), MMP-1, TNFRSF9, Transforming growth factor-α (TGF-α), 4E-BP1, and CASP-8 were significantly downregulated in PCV relative to nAMD. Boxplot analysis confirmed that Flt3L, IL-18, IL-1α, IL-7, IL-8, MCP-1, MMP-1, OPG, SCF, and VEGFA were specifically elevated in nAMD compared with both PCV and NC groups, while IL-10 was specifically suppressed in PCV. Conclusions: Tear fluid analysis represents a feasible and noninvasive approach to investigate the pathogenesis of PCV and nAMD.

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is recognized as a systemic syndrome that manifests with a range of complications including mineral dysregulation, skeletal abnormalities, and vascular calcification (VC). Recent research has increasingly pointed toward immune dysregulation as a pivotal factor in the development and progression of this disorder. The current review endeavors to consolidate the latest findings regarding how chronic inflammation, dysfunction of immune cells, and disturbances in the gut-kidney axis contribute to the progression of CKD-MBD. Central to the mechanisms at play are pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-6, which are found to facilitate bone resorption through the activation of the receptor activator of NF-kappaB ligand (RANKL)/receptor activator of nuclear factor-kappa B (RANK)/osteoprotegerin (OPG) signaling pathway. Furthermore, macrophage-induced VC is linked to the activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome. Additionally, an imbalance between osteoblasts and osteoclasts, driven by uremic toxins, exacerbates the skeletal manifestations of the disorder. Despite the availability of current therapeutic options, including phosphate binders and vitamin D analogs, these treatments fall short in adequately addressing the immune-mediated aspects of CKD-MBD, indicating an urgent need for innovative strategies that effectively target inflammatory pathways, inhibit sclerostin, or modulate fibroblast growth factor (FGF)-23 levels. Emerging preclinical studies have shown that sodium-glucose cotransporter 2 (SGLT2) inhibitors and anti-sclerostin antibodies hold significant promise in lessening VC and enhancing bone health. However, translating these findings into clinical application encounters hurdles related to the diversity of patient populations and the dependence on surrogate endpoints for efficacy. This review emphasizes the critical need for incorporating immune-centric strategies into the management of CKD-MBD. It advocates for the development of biomarker-driven, personalized therapies and highlights the importance of conducting longitudinal studies to bridge the existing gaps in knowledge and improve patient outcomes.

The objective of our study was to examine the role of Chemerin, Chemokine like receptor 1 (CMKLR1), receptor activator of nuclear factor kappa-Β ligand (RANKL), and Osteoprotegerin (OPG) in the development of bone-invasive oral squamous cell carcinoma. In order to evaluate the presence of these markers at the interface between bone and tumor, immunohistochemical analyses were conducted using tissue microarrays obtained from 164 patients with oral squamous cell carcinoma growing in close contact with jaw bone. The findings indicate that Chemerin and Osteoprotegerin are notably reduced in tumors that have invaded the bone. Only 21 (32.8%) of pT4a tumors (defined as bone invasive) had a high Osteoprotegerin expression, whereas 36 (66.7%) of pT2 and pT3 tumors demonstrated high expression of Osteoprotegerin (p < 0.001). Similarly, we saw a downregulation of Chemerin in 50 (60.2%) bone invasive oral squamous cell carcinoma samples compared to 28 (35.0%) in non-bone invasive tumors (p = 0.002). In addition, our data indicated a connection between worst pattern of invasion score and less favorable overall and disease-specific survival (p = 0.007 and p = 0.024, respectively). The findings suggest that Chemerin and Osteoprotegerin have the potential to serve as indicators for bone invasion in oral squamous cell carcinoma, which could have significant implications for diagnosis and treatment approaches.

Osteoporosis is a common bone disease, especially in women after menopause and with aging, where bones become more fragile due to decreased density and structural changes. This condition is closely linked to a decline in estrogen levels, leading to accelerated bone loss due to an imbalance between bone-forming cells (osteoblasts) and bone resorbing cells (osteoclasts).With aging and the decline in estrogen levels after menopause, caused by the cessation of egg production in the ovaries, the production of inflammatory factors such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor (TNF) increases, while the level of the regulatory protein OPG decreases. This imbalance leads to higher bone turnover and osteoporosis. Additionally, it contributes to vascular calcification due to the increased activity of RANKL on bone and vascular cells.Objectives: Evaluate the differences in Osteoprotegerin (OPG) and Estradiol (E2) levels between Iraqi women with osteoporosis and those with osteopenia to determine the impact of these biomarkers on bone health.Method and patients: Three group in this study of population divided into patient group(n=39) seemingly healthy volunteers as control group ,Additionally, 33 women suffered from osteopenia and 34 women suffered from osteoporosis All participants underwent bone mineral density assessment using dual-energy X-ray absorptiometry.Medical examinations, including laboratory tests for women, were conducted at Al-Alwiya Hospital in Baghdad Province, in addition to other tests performed at Al-Wasiti teaching Hospital. Results: The DEXA outcomes revealed osteopenia patients had a higher mean age (49.6 ± 14.17 years) than the control group (42.25 ± 13.13 years), while osteoporosis patients were the oldest (57.47 ± 11.28 years, p = 0.015). Osteoprotegerin levels were highest in the control group (6.47 ± 1.69 ng/ml) and significantly lower in osteopenia (5.56 ± 1.91 ng/ml, p = 0.036) and osteoporosis patients (4.85 ± 1.46 ng/ml, p &lt; 0.001). The decline in osteoprotegerin was more pronounced between healthy individuals and osteopenia patients, while the difference between osteopenia and osteoporosis patients was not significant (p = 0.089). Conclusion: Aging is associated with decreased OPG and estradiol levels, leading to bone imbalance and increased loss. The significant decline from osteopenia to osteoporosis highlights the crucial role of hormonal disturbances in disease progression.

Osteoporosis is a chronic metabolic disease characterised by reduced bone mineral density (BMD) and increased susceptibility to fractures. Its development is influenced by both environmental and genetic factors that regulate bone metabolism. Among the genes involved in bone metabolism, COL1A1 and TNFRSF11B (OPG) are particularly important. The COL1A1 gene encodes the alpha-1 chain of type I collagen, a major component of the bone matrix, and plays a key role in maintaining bone mechanical strength. The TNFRSF11B gene encodes osteoprotegerin (OPG), a protein that inhibits bone resorption by binding the RANKL ligand and blocking osteoclast activation. Therefore, the aim of this study was to determine the association between the rs1107946 and rs1800012 polymorphisms of the COL1A1 gene and the rs2073617 polymorphism of the TNFRSF11B (OPG) gene and bone mineral density in postmenopausal women. The study included 590 postmenopausal women: 350 healthy controls, 105 with osteopenia, and 135 with osteoporosis. Genotyping was performed using real-time PCR and LightSNiP probes. Associations between genetic variables and BMD were assessed, taking into account environmental factors (BMI, smoking). The presence of the T allele of the rs1800012 variant was initially associated with lower BMD and an increased risk of osteopenia, but this association lost significance after adjustment for BMI and smoking. For rs1107946 and rs2073617,no statistically significant associations were observed. These findings suggest that the studied SNPs have, at most, modest effects on BMD, with environmental influences playing a stronger role. Further research in larger and more diverse cohorts, including FRAX-based risk estimation, is warranted.

BackgroundPostmenopausal osteoporosis (PMOP) is a prevalent metabolic disorder characterized by pathogenic mechanisms associated with the dysfunction of osteoclasts (OC) and osteoblasts (OB). Icaritin (ICT) is a flavonoid derived from icariin and epimedium, which is a natural product, and has demonstrated promising anti-osteoporosis properties. Nevertheless, the targets and mechanisms of ICT in osteoclast differentiation and PMOP remain unclear.Methodswe developed a bilateral ovariectomy-induced osteoporosis model in animals and receptor activator of nuclear factor kappa-B ligand (RANKL) induced RAW264.7 to differentiate into osteoclasts with or without MPP dihydrochloride (MPP) and antagomir-503-5p. Micro-CT, tartrate-resistant acid phosphatase (TRAP) staining, enzyme-linked immunosorbent assay (ELISA), Western blot and qRT-PCR were used to detect bone resorption function, bone metabolism parameters, osteoclast differentiation rate and the expression of related genes, as well as the expression of ESR1, miR-503 and RANK. Molecular docking, cell thermal shift assay (CETSA) and drug affinity responsive target stability (DARTs) experiments were used to confirmed that ESR1 is the direct target of ICT, and binding site of ICT with ESR1.ResultsICT significantly inhibited OC differentiation and the expression of related genes (Trap, Mmp9, and Nfatc1), reduced bone loss, and improved osteoporosis and bone trabecular structure, and inhibited the levels of TRAP and RANKL in the serum and increase the level of osteoprotegerin (OPG). ICT significantly enhanced the expression of ESR1, ESR2 and miR-503, while inhibiting RANK expression, and ESR1 is the direct target of ICT, and Asparagine at 455 is the direct binding site of ICT with ESR1. Moreover, blocking ESR1 significantly reduced the regulatory effect of ICT on OC differentiation and related gens expression by MPP, especially the expression of miR-503 and RANK, as well as weakened the regulatory effect of ICT on inhibiting bone loss. Antagomir-503-5p significantly reduced the regulatory effect of ICT on OC differentiation, as well as the expression of genes related to OC differentiation.ConclusionTaken together, our study confirmed that ESR1 is the direct target of ICT, and Asparagine at 455 is the direct binding site of ICT, and ICT inhibits OC differentiation and reduces bone loss by targeting ESR1 to upregulate miR503 level and weaken miR503/RANK pathway.

The increasing global population of the elderly and rising life expectancy have made osteoporosis a more severe public health issue, necessitating the development of safer and more effective therapeutic strategies. This study investigated the osteoprotective effects of low, medium, and high doses of oyster peptide (OP) in dexamethasone (DEX)-induced osteoporotic rats. Pathological analysis showed that OP treatment effectively mitigated bone loss and repaired bone microarchitecture deterioration caused by DEX administration. In the OP groups, levels of the osteogenic markers osteocalcin (OCN) and osteoprotegerin (OPG) were significantly higher than in the DEX group. Moreover, levels of the osteoclastic markers RANKL, Cathepsin K (Cath-K), MMP-9, C-terminal telopeptide of type I collagen (CTX-1), and Deoxypyridine (DPD) were significantly lower. Bone proteomic analysis of the DEX and OP groups revealed that differentially expressed proteins were significantly enriched in pathways related to extracellular matrix and structural reorganization, ECM–receptor interaction, and PI3K-Akt signaling. Furthermore, virtual screening simulations indicated that peptides with lengths ranging from 11 to 20 amino acid residues were involved in modulating the activity of key receptors in these pathways, including Integrins α5β1, Integrins αvβ3, and EGFR. Collectively, these results demonstrate the significant potential of OP as a novel therapeutic agent for osteoporosis.

Objective: To analyze the value of H-FABP and OPG in determining severity of heart function in those suffering from long-term heart failure. Method: 196 patients with persistent heart failure who were admitted to our hospital between June 2023 and October 2024 were chosen. A comparison was made between the three groups of chronic heart failure patients' general clinical information, H-FABP, and OPG levels. The associations between OPG and H-FABP and various clinical forms of chronic heart failure, heart failure severity, and measurement markers related to echocardiography were examined. To assess NT-proBNP, H-FABP, and OPG detection alone and in combination for HFrEF and HFpEF in order to determine their diagnostic utility. Following their discharge, all patients were monitored for three to six months. Results: There was a positive correlation (r=0.61) between H-FABP and the NYHA classification, LA (r=0.46), LV (r=0.51), HS-TnT (r=0.31), NT-proBNP (r=0.58), SUA (r=0.38), etc., and negatively correlated with the LVEF (r=-0.76), NT-proBNP (r=0.49), etc., and negatively correlated with the LVEF (r=-0.60) (P&lt;0.05). Binary logistic regression analysis of NT-proBNP, H-FABP, and OPG levels and endpoint events revealed that NT-proBNP had a high value in predicting endpoint events. The readmission rate and mortality rate of patients with chronic heart failure increased with increasing NT-proBNP concentration. Serum H-FABP and OPG all have high diagnostic value for HFrEF. Compared with the traditional biomarker NT-proBNP, H-FABP had a greater sensitivity (94.9%) and specificity (83.1%) in the diagnosis of HFrEF, whereas OPG had a greater sensitivity (92.3%) and a lower specificity (57.7%). H-FABP and OPG can significantly improve the sensitivity (86.44%) and specificity (89.74%) in the diagnosis of patients with HFrEF. Serum NT-proBNP, H-FABP and OPG all have high diagnostic value for HFpEF. Compared with the traditional biomarker NT-proBNP, H-FABP has greater sensitivity (91.7%) and specificity (82.0) in the diagnosis of HFpEF, whereas OPG has greater specificity (82.0%) and lower sensitivity (58.3%). Conclusion: The combined detection of H-FABP, OPG and NT-proBNP can be used as an important strategy for the early detection of heart failure patients' declining cardiac function.

Breast cancer continues to be a significant global health issue and is associated with various biological indicators, including osteoprotegerin (OPG), a glycoprotein involved in bone metabolism, tumor progression, and immunological modulation. This study examined the potential of OPG as a biomarker for breast cancer and its correlation with bone health, vitamin D levels, and calcium concentrations. To quantify serum OPG levels in breast cancer patients and assess its viability as a diagnostic biomarker. In addition, to evaluate vitamin D levels due to their established correlation with an increased cancer risk in cases of deficiency. The study also examined parathyroid hormone (PTH) and calcium levels in breast cancer patients. Blood samples were obtained from female volunteers at the Oncology Teaching Hospital, Medical City, Baghdad, Iraq (September 2023 - February 2024). The study comprised three cohorts: healthy controls (G1, n=40), newly diagnosed breast cancer patients (G2, n=45), and patients undergoing chemotherapy (G3, n=45). Serum concentrations of OPG, vitamin D, PTH, and calcium were quantified using ELISA methodologies. No statistically significant variations in OPG levels were observed between the control and patient groups, indicating minimal bone resorption during the early stages of breast cancer. Vitamin D levels were markedly reduced in G2 compared with the control group, while G3 showed a modest increase in vitamin D levels attributable to supplementation. Increased PTH levels were observed in breast cancer patients, supporting prior research linking elevated PTH with increased cancer risk. No notable differences were found in serum calcium levels among the groups. Vitamin D and PTH levels are crucial in early-stage breast cancer development, underscoring the need for monitoring these factors and questioning the diagnostic efficacy of OPG alone.

Stereotactic body radiation therapy (SBRT) for lung tumors near the chest wall often causes significant chest wall pain (CWP), negatively impacting patients’ quality of life. The mechanisms behind SBRT-induced CWP remain unclear and may involve multiple factors. We investigated crosstalk between radiation-activated osteoclasts and sensory neurons, focusing on osteoclast-derived factors in CWP. Using murine pre-osteoclast cell line Raw264.7, we induced differentiation with Receptor Activator of Nuclear Factor kappa-beta Ligand (RANKL), followed by 10 Gy gamma-irradiation. Conditioned media (C.M) from irradiated osteoclasts was used to treat sensory neuronal cultures from mouse dorsal root ganglia. Neuronal cultures were also exposed to 10 Gy radiation, with and without osteoclast co-culture. Osteoclast markers and pain-associated neuropeptides were analyzed using RT-qPCR and histochemical staining. Osteoclasts differentiation and activity were inhibited using osteoprotegerin (OPG) and risedronate. High-dose radiation significantly increased the size of tartrate-resistant-acid-phosphatase (TRAP)-positive osteoclasts (1.36-fold) and activity biomarkers (Ctsk, 1.35-fold, Mmp9, 1.76-fold). Neurons treated with C.M from irradiated osteoclasts showed ~1.5-fold increase in Calca (calcitonin gene-related peptide) and Tac1 (substance P) expression, which was mitigated by osteoclast inhibitors. These findings suggest that radiation enhances osteoclast activity and promotes pain signaling. Osteoclast inhibitors may represent a therapeutic strategy to reduce CWP and improve quality of life.

Objective Osteoporosis (OP) is a systemic skeletal disease that increases the risk of fractures by weaking bone. Hypoxia-inducible factor-1α (HIF-1α) plays a crucial role in osteogenesis and osteoblastic differentiation. The purpose of this study is to examine the underlying mechanism of HIF-1α overexpression and its impact on osteoblast development. Methods First, we used the autophagy inhibitor 3-MA in conjunction with either a control lentivirus or an HIF-1α overexpression lentivirus to transfect rat osteoblasts in osteogenic induction media for 3, 7, 14, and 21 days. The effects of HIF-1α overexpression on osteogenic differentiation were evaluated using CCK-8, alkaline phosphatase (ALP) staining, and Alizarin Red staining. Furthermore, we investigated the mechanism by which HIF-1α overexpression mediates autophagy to regulate osteogenic differentiation through immunofluorescence, western blot, and transmission electron microscopy. Ovariectomy (OVX) was performed to establish an osteoporotic rat model. The impact of HIF-1α overexpression on autophagy and bone metabolism was evaluated by locally injecting HIF-1α overexpression lentivirus or control lentivirus, in combination with HE staining, micro-CT, immunohistochemistry, ELISA, western blot, and transmission electron microscopy. Results Overexpression of HIF-1a promotes osteoblast proliferation and enhances ALP staining as well as calcium nodule formation. In addition, the overexpression of HIF-1a significantly increases the relative protein expression levels of osteocalcin (OCN), osteoprotegerin (OPG), HIF-1a, BNIP3, Beclin1, ATG5, and LC3 II/I. This indicates that HIF-1a may facilitate osteoblast differentiation by promoting autophagy. These findings were further corroborated by in vivo experiments, which demonstrated improved pathological morphology in rat femurs, alongside increased bone mineral density (BMD), trabecular thickness (Tb. Th), bone volume/total volume ratio (BV/TV), and trabecular number (Tb. N). Additionally, there was a decrease in trabecular separation (Tb. Sp) and structural model index (SMI), along with upregulated expression of OCN, OPG, HIF-1α, BNIP3, Beclin1, ATG5, and LC3 II. Conclusion HIF-1a overexpression can promote osteogenic differentiation and ameliorate osteoporosis through the induction of autophagy. These insights provide a valuable reference for its potential application in targeted therapy. Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-16046-w.