Inhibition Of Bone Resorption Research Articles

Nanographene Oxide Promotes Angiogenesis by Regulating Osteoclast Differentiation and Platelet-Derived Growth Factor Secretion.

An imbalanced system of angiogenesis-osteoblasts-osteoclasts is regarded as the main factor in bone remodeling dysfunction diseases or osseointegration loss. Osteoclast precursors are the key cells that accelerate bone-specific angiogenesis and maintain normal osteoblast and osteoclast function. Graphene oxide is an effective scaffold surface modification agent with broad application prospects in bone tissue engineering. However, the effect of graphene oxide on the interaction between osteoclasts and angiogenesis has not yet been elucidated. In this study, a rat calvarial defect model was established and treated with an electrochemically derived nanographene oxide (ENGO) hydrogel. Higher angiogenesis and platelet-derived growth factor (PDGF) B in preosteoclasts were observed in the ENGO group compared with that in the control group. Moreover, in vitro experiments demonstrate the efficacy of ENGO in substantially reducing the expression of the receptor activator of nuclear factor-kappaB ligand (RANKL)-induced osteoclast-associated markers and inhibiting bone resorption activity. Additionally, ENGO enhances the secretion of the osteoclast-derived coupling factor PDGF-BB and promotes angiogenesis. Our investigation revealed the crucial role of isocitrate dehydrogenase 1 (IDH1) in the ENGO-mediated regulation of osteoclast differentiation and PDGF-BB secretion. The decreased expression of IDH1 reduces the level of histone lysine demethylase 7A (KDM7A) and subsequently increases the H3K9me2 level in the cathepsin K promoter region. In summary, we found that ENGO promotes angiogenesis by inhibiting the maturity of RANKL-induced osteoclasts and enhancing PDGF-BB secretion. These results indicate that ENGO holds promise for the application in fostering osteoclast-endothelial cell crosstalk, providing an effective strategy for treating bone resorption and osteoclast-related bone loss diseases.

Applications of Bioactive Strontium Compounds in Dentistry

Divalent cations have captured the interest of researchers in biomedical and dental fields due to their beneficial effects on bone formation. These metallic elements are similar to trace elements found in human bone. Strontium is a divalent cation commonly found in various biomaterials. Since strontium has a radius similar to calcium, it has been used to replace calcium in many calcium-containing biomaterials. Strontium has the ability to inhibit bone resorption and increase bone deposition, making it useful in the treatment of osteoporosis. Strontium has also been used as a radiopacifier in dentistry and has been incorporated into a variety of dental materials to improve their radiopacity. Furthermore, strontium has been shown to improve the antimicrobial and mechanical properties of dental materials, promote enamel remineralization, alleviate dentin hypersensitivity, and enhance dentin regeneration. The objective of this review is to provide a comprehensive review of the applications of strontium in dentistry.

Osteogenic effect of an adiponectin-derived short peptide that rebalances bone remodeling: a potential disease-modifying approach for postmenopausal osteoporosis therapy.

Adiponectin, an adipokine, regulates metabolic processes, including glucose flux, lipid breakdown, and insulin response, by activating adiponectin receptors 1 and 2 (AdipoR1 and AdipoR2). We have previously shown that globular adiponectin (gAd), an endogenous form of adiponectin, has osteoanabolic and anti-catabolic effects in rodent models of postmenopausal osteopenia. Moreover, we reported the identification of a 13-mer peptide (ADP-1) from the collagen domain of adiponectin, which exhibited significant adiponectin-mimetic properties. Since the clinical development of gAd is constrained by its large size, here, we investigated the osteogenic property of ADP-1. ADP-1 induced osteoblast differentiation more potently than gAd. ADP-1 elicited osteoblast differentiation through two downstream pathways that involved the participation of adiponectin receptors. Firstly, it enhanced mitochondrial biogenesis and OxPhos, leading to osteoblast differentiation. Secondly, it activated the Akt-glycogen synthase kinase 3β-Wnt pathway, thereby increasing osteoblast differentiation. Additionally, ADP-1 suppressed the production of receptor-activator of nuclear kappa B ligand from osteoblasts, enabling it to act as a dual-action molecule (suppressing osteoclast function besides promoting osteoblast function). In osteopenic ovariectomized rats, ADP-1 increased bone mass and strength and improved trabecular integrity by stimulating bone formation and inhibiting bone resorption. Furthermore, by increasing ATP-producing intermediates within the tricarboxylic acid cycle in bones, ADP-1 likely fueled osteoblast function. Given its dual-action mechanism and high potency, ADP-1 offers a unique opportunity to address the unmet clinical need to reset the aberrant bone remodeling in osteoporosis to normalcy, potentially offering a disease-modifying impact.

LL-37 and bisphosphonate co-delivery 3D-scaffold with antimicrobial and antiresorptive activities for bone regeneration

This study introduces a novel 3D scaffold for bone regeneration, composed of silk fibroin, chitosan, nano-hydroxyapatite, LL-37 antimicrobial peptide, and pamidronate. The scaffold addresses a critical need in bone tissue engineering by simultaneously combating bone infections and promoting bone growth. LL-37 was incorporated for its broad-spectrum antimicrobial properties, while pamidronate was included to inhibit bone resorption. The scaffold's porous structure, essential for cell infiltration and nutrient diffusion, was achieved through a freeze-drying process. In vitro assessments using SEM and FTIR confirmed the scaffold's morphology and chemical integrity. Antimicrobial efficacy was tested against pathogens of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). In vivo studies in a murine model of infectious bone defect revealed the scaffold's effectiveness in reducing inflammation and bacterial load, and promoting bone regeneration. RNA sequencing of treated specimens provided insights into the molecular mechanisms underlying these observations, revealing significant gene expression changes related to bone healing and immune response modulation. The results indicate that the scaffold effectively inhibits bacterial growth and supports bone cell functions, making it a promising candidate for treating infectious bone defects. Future studies should focus on optimizing the release of therapeutic agents and evaluating the scaffold's clinical potential.

Phytic Acid-Gallium Network on a Polyimide Fiber Woven Fabric as an Artificial Ligament for Boosting Ligament-Bone Healing and Infection Treatment.

The development of an artificial ligament with a multifunction of promoting bone formation, inhibiting bone resorption, and preventing infection to obtain ligament-bone healing for anterior cruciate ligament (ACL) reconstruction still faces enormous challenges. Herein, a novel artificial ligament based on a PI fiber woven fabric (PIF) was fabricated, which was coated with a phytic acid-gallium (PA-Ga) network via a layer-by-layer assembly method (PFPG). Compared with PIF, PFPG with PA-Ga coating significantly suppressed osteoclastic differentiation, while it boosted osteoblastic differentiation in vitro. Moreover, PFPG obviously inhibited fibrous encapsulation and bone absorption while accelerating new bone regeneration for ligament-bone healing in vivo. PFPG remarkably killed bacteria and destroyed biofilm, exhibiting excellent antibacterial properties in vitro as well as anti-infection ability in vivo, which were ascribed to the release of Ga ions from the PA-Ga coating. The cooperative effect of the surface characteristics (e.g., hydrophilicity/surface energy and protein absorption) and sustained release of Ga ions for PFPG significantly enhanced osteogenesis while inhibiting osteoclastogenesis, thereby achieving ligament-bone integration as well as resistance to infection. In summary, PFPG remarkably facilitated osteoblastic differentiation, while it suppressed osteoclastic differentiation, thereby inhibiting osteoclastogenesis for bone absorption while accelerating osteogenesis for ligament-bone healing. As a novel artificial ligament, PFPG represented an appealing option for graft selection in ACL reconstruction and displayed considerable promise for application in clinics.

Effect of Xanthohumol from Humulus lupulus L. Against Gouty Bone Damage in Arthritis of Rats Induced by Mono-sodium Urate.

Xanthohumol (XAN) is an isoprenyl flavonoid from Humulus lupulus L. known for beer brewing, and an osteoprotective agent due to its active improvement in bone loss of osteoporosis. This study was first time to investigate its effects on anti-gouty bone injury in rats of gouty arthritis (GA) induced by monosodium urate (MSU). Results showed that XAN could significantly exert anti-inflammatory activity by alleviating swelling degree of joints, reducing serum level of inflammatory factors, improving inflammatory injury and degrading the Markin's score in lesion joint. Meanwhile, XAN could also fight against gouty bone damage by improving pathological changes of bone tissue and parameters of bone micro-structure. Moreover, XAN could even promote bone formation by effectively enhancing expression of Runx2 and OPG, while inhibit bone resorption with depressing matrix metalloproteinase-9 (MMP-9), MMP-13 and CTSK expression, reducing RANKL secretion, and abating the ratio of RANKL/OPG. Therefore, it was the first time to reveal the mechanism of XAN against gouty bone injury via inhibiting RANKL/OPG/RANK signaling pathway. Above all, this study provided potential strategy for the treatment of GA, and further contributed to research and resource development for hops.

Potential for Drug Repositioning of Midazolam as an Inhibitor of Inflammatory Bone Resorption.

Drug repositioning is a method for exploring new effects of existing drugs, the safety and pharmacokinetics of which have been confirmed in humans. Here, we demonstrate the potential drug repositioning of midazolam (MDZ), which is used for intravenous sedation, as an inhibitor of inflammatory bone resorption. We cultured a mouse macrophage-like cell line with or without MDZ and evaluated its effects on the induction of differentiation of these cells into osteoclasts. For in vivo investigations, we administered lipopolysaccharide (LPS) together with MDZ (LPS+MDZ) to the parietal region of mice and evaluated the results based on the percentage of bone resorption and calvaria volume. Furthermore, we examined the effects of MDZ on the production of reactive oxygen species (ROS) in cells and on its signaling pathway. MDZ inhibited osteoclast differentiation and bone resorption activity. In animal studies, the LPS+MDZ group showed a decreasing trend associated with the rate of bone resorption. In addition, the bone matrix volume in the LPS+MDZ group was slightly higher than in the LPS only group. MDZ inhibited osteoclast differentiation by decreasing ROS production and thereby negatively regulating the p38 mitogen-activated protein kinase pathway. Thus, we propose that MDZ could potentially be used for treating inflammatory bone resorption, for example, in periodontal disease.

Adverse skeletal related events in patients with bone-metastatic pheochromocytoma/paraganglioma

Metastatic pheochromocytomas and paragangliomas (PPGLs) are frequently associated with skeletal complications.Primary objective: to describe the frequency of adverse skeletal related events (SREs) in PPGL patients with bone metastases (BMs). Secondary objectives: to 1) identify predictive and prognostic factors for SREs and 2) obtain information on the effectiveness of bone resorption inhibitors in reducing SRE risk and improving outcomes in term of survival and SREs time onset.In this retrospective multicenter, multinational study, 294 PPGL patients were enrolled.SREs occurred in 90 patients (31 %). Fifty-five patients (19 %) had bone fractures, 47 (16 %) had spinal cord compression, and 11 (4 %) had hypercalcemia. Twenty-two patients (7 %) had more than one SRE. Sixty-four patients (22 %) underwent surgery, and 136 (46 %) underwent radiotherapy. SREs occurred a median of 4.4 months after diagnosis of BM (range, 0–246.6 months). Independent factors associated with reduced risk of SREs in multivariable analysis were I-131-MIBG radionuclide therapy (hazard ratio [HR], 0.536 [95 % CI, 0.309–0.932]; P = .027) and absence of liver metastases (HR, 0.638 [95 % CI, 0.410–0.992]; P = .046). The median overall survival duration was 5.3 year. In multivariable analysis, age younger than 48 years at PPGL diagnosis (HR, 0.558 [95 % CI, 0.3877–0.806]; P = .002), absence of liver metastases (HR, 0.618 [95 % CI, 0.396–0.965]; P = .034), treatment with bisphosphonates or denosumab (HR, 0.598 [95 % CI, 0.405–0.884]; P = .010), and MIBG radionuclide therapy (HR, 0.444 [95 % CI, 0.274–0.718]; P = .001) were associated with a reduced risk of death.SREs occur frequently and early in bone-metastatic PPGL patients but do not negatively impact survival. MIBG radionuclide therapy and treatment with bone resorption inhibitors are associated with favorable outcome.

Investigating the Underlying Molecular Mechanisms of Yunke on Bone Metastases from Prostate Cancer.

To explore analgesic effect and bone repair mechanism of non-radioactive technetium-99 conjugated with methylene diphosphonate (99Tc-MDP, brand name, Yunke) on bone metastases (BM). In vivo experiment, mouse BM models of prostate cancer RM-1 cell were constructed and divided into Control, Yunke, 99Tc+SnCl2 and MDP groups based on medicine composition. Tumor specimens were inspected for size, X-ray, microCT and histopathology. In vitro experiment, with Cell Counting Kit-8 (CCK8), scratch, clone, apoptosis, Polymerase Chain Reaction (PCR) and Western Blot experiments, effects of Yunke on RM-1 cells and osteoclast-related cells were observed. In vivo experiment, there was no difference in tumor size between Yunke and control group. Contrasted with control group, in Yunke group, trabecular spacing (Tb.Sp) of tumor bone was lower, bone volume/total volume (BV/TV) on marrow cavity and bone cortex were higher. Tunnel staining showed that positive rate of apoptosis in Yunke group was higher than that in control group. Ki67 staining showed that Yunke could not inhibit proliferation of tumor cells. In vitro experiment, CCK8 and scratch experiments showed that Yunke neither can inhibit proliferation nor can inhibit migration of RM-1 cells. High concentration of Yunke promoted late apoptosis of RM-1 cells. Yunke could inhibit BMM cell proliferation, differentiation of osteoclasts, and osteoclast-related transcription factors. Yunke displayed different degrees of inhibitory effects on MAPKs signaling pathway during osteoclast differentiation. It had obvious inhibitory effects on osteoclast-related transcription factors, such as cFOS, NFATC1, ACP-5, CTSK, D2 and MMP-9, the strongest inhibitory effects were observed with ACP-5, CTSK and D2. Yunke also displayed different degrees of inhibitory effects on protein activities of JNK, pERK, ERK and pP38. Yunke cannot inhibit the proliferation and migration of RM-1 cells, so we think it is not recommended for the treatment of primary tumors and prevention of occurrence of tumors metastatic to bones. The mechanism of therapeutic effect of Yunke on BM by inhibiting proliferation of BMM, inhibiting MAPKs signal transduction and activation of transcription factors during differentiation process of BMM-derived osteoclasts, inhibiting number and size of osteoclasts, inhibiting bone resorption and protecting bone destruction through enhancing bone hardness and bone mass. Thereby, we believe that Yunke is more suitable for promoting the repair induced by BMs, delaying its progression and reducing the occurrence of SREs.

The Current Status of Sequential Therapy with Commonly Used Anti-Osteoporosis Drugs

As the trend of population aging intensifies, the incidence of osteoporosis is rising correspondingly. Osteoporotic fractures are one of the primary causes of disability and death in elderly patients, placing a great burden on both families and society in terms of medical care resources. The monotherapy of osteoporosis drugs has certain limitations and sequential drug treatment should be considered under the following circumstances: (i) when bone resorption inhibitors fail to work, have been used for too long, or cause adverse reactions; (ii) when the recommended treatment course of bone formation promoters (such as parathyroid hormone analogues) has ended but the patient's fracture risk remains high and requires continued treatment; (iii) when short-acting drugs such as teriparatide or denosumab need to maintain treatment effects after discontinuation. The sequential therapy of osteoporosis drugs can be categorized according to the mechanism of action into the following schemes: (i) bone formation promoters followed by bone resorption inhibitors; (ii) bone resorption inhibitors followed by bone formation promoters; (iii) different types of bone resorption inhibitors used sequentially; (iv) other sequential drug treatments. Osteoporosis is a progressive disease, and the ageing of the human population cannot be reversed. Therefore, single-drug treatment is unlikely to achieve the goal of long-term disease prevention and control, making the exploration of long-term treatment plans for existing drugs a key aspect of osteoporosis drug treatment.

Melatonin prevents cadmium-induced osteoporosis by affecting the osteoblast and osteoclast differentiation and pyroptosis in duck

Cadmium (Cd), is a highly toxic environmental pollutant, which seriously threatens the health of poultry and humans. The occurrence of osteoporosis is the main manifestation of cadmium toxicity. Pyroptosis plays an important role in the development of osteoporosis. Melatonin has been shown to affect preserving bone health. However, the underlying mechanism has not been elucidated. In the present study, these functions of melatonin have been investigated in duck bone tissue and osteoblast during cadmium exposure. In vivo, the studies suggest that melatonin protects against cadmium-induced duck osteoporosis by improving the osteogenesis function, inhibiting bone resorption, and suppressing the occurrence of pyroptosis. In vitro, the findings demonstrated that melatonin alleviated the inhibition effect of cadmium on duck bone marrow-derived mesenchymal stem cells (BMSC) osteogenic differentiation, and suppressed the cadmium-induced osteoclast differentiation. In addition, we also found that melatonin prevents cytokines release of lactate dehydrogenase (LDH), interleukin-18 (IL-18), and interleukin-1β (IL-1β) by cadmium-induced, and reduces the expression of n-terminal Gasdermin D (N-GSDMD), alleviates the osteoblast death rate. In short, melatonin as a potential therapeutic agent has bright prospects in cadmium-induced bone toxicity.

Fabrication and in vitro biological performance of a double-layered nanoparticles-microarc oxidation composite coating on titanium for dental implant application

Sufficient residual alveolar bone volume plays an important role in the success rate and service life of dental implants. However, alveolar bone deficiency is a common clinical phenomenon, and the alveolar bone would be further absorbed by peri-implant infection. Therefore, it is highly desirable to promote peri-implant alveolar bone regeneration and inhibit alveolar bone resorption when the alveolar bone mass is insufficient. For this purpose, a pH-sensitive double-layered nanoparticles-microarc oxidation (MAO) composite coating was fabricated on titanium for dental implant application in this study. The pH-sensitive double-layered nanoparticles were prepared by a poly(L-lactic acid) inner layer and a chitosan outer shell, containing stromal-cell derived factor-1, recombinant human bone morphogenetic protein 2 and osteoprotegerin. The composite coating was fabricated on MAO coating by cross-linking the pH-sensitive double-layered nanoparticles with gelatin. The surface morphology of the composite coating showed that the pH-sensitive double-layered nanoparticles were well distributed and tightly cross-linked in the pores of MAO coating. The composite coating could sustain release the three drugs for more than 30 days. With decreasing pH, the release of osteoprotegerin from the composite coating increased (p < 0.05). In vitro biological studies suggested that the composite coating exhibited no cytotoxicity, and can recruit bone marrow-derived mesenchymal stem cells (BMSCs), promote BMSC differentiation into osteoblasts, and inhibit osteoclast generation. Moreover, with decreasing pH, the inhibitory effect on osteoclast generation was enhanced (p < 0.05). It can be concluded that the fabricated composite coating, which can promote bone regeneration and inhibit bone resorption, has the potential to be applied on the surface of dental implant, especially when the residual alveolar bone is in poor condition.

A phase Ib study of JMT103, a receptor activator of NF-kB ligand (RANKL) antibody, in patients (pts) with bone metastases from solid tumors.

e15190 Background: JMT103 is a human IgG4 monoclonal antibody against RANKL and blocks the RANK signaling in osteoclasts, thus suppressing bone resorption. This phase Ib study aims to demonstrate the activity of JMT103 in bone metastases patients with solid tumors. Methods: In this randomized, multi-center, open-label, phase Ib study, adult pts with bone metastases from solid tumors were enrolled and randomized at a 1:1:1 ratio to receive JMT103 subcutaneously at 120mg every 4 weeks (Q4W, Cohort 1), 120mg every 8 weeks (Q8W, Cohort 2) and 180mg Q8W (Cohort 3) up to 49 weeks. The primary endpoint was the percent change from baseline to week 13 in creatinine-adjusted urinary N-telopeptide (uNTx/Cr). Secondary endpoints included safety, anti-drug antibodies (ADA) positivity, the percentage of patients who experienced on-study skeletal-related events (SREs), and ≥ 2-point decreases in pain with Brief Pain Inventory – Short Form. Results: At database lock (Mar. 31, 2023), 295 pts were enrolled; 293 were treated with JMT103 and eligible for efficacy and safety evaluation (96 pts in Cohort 1, 97 pts in Cohort 2, and 100 pts in Cohort 3). The median age was 58 years (Interquartile range [IQR] 51, 66), and the primary tumor types were mainly breast (145, 50%) and prostate cancer (44, 15%). At week 13, the median (IQR) percent change in uNTx/Cr was - 80% (- 93%, - 50%) in Cohort 1, - 73% (- 94%, - 34%) in Cohort 2, and - 76% (- 92%, - 40%) in Cohort 3, respectively. The incidence of SREs in the three cohorts was 3%, 6%, and 7%, respectively. Among the 33 pts in Cohort 1, 35 pts in Cohort 2, and 37 pts in Cohort 3 with baseline pain scores ≥ 2, 61% in Cohort 1, 46% in Cohort 2, and 54% in Cohort 3 experienced ≥ 2-point decreases in pain at the first post-treatment visit (Day 15). For ADA analysis, only 1 (1%) pt in Cohort 2 with a negative result at baseline tested positive after treatment. The table shows the overall summary of the safety profile. Most of TRAEs were low in grade and resolved quickly. The most common TRAEs (any grade) were hypocalcemia (68, 23%), hypophosphatemia (67, 23%), and increased aspartate transaminase (35, 12%). Among the 40 cases of grade-5 TEAE, only 1 was reported as a TRAE (pneumonia); the rest were unrelated to JMT103. Conclusions: Our study demonstrated a promising efficacy of JMT103 in reducing bone metabolism biomarker and a good safety profile with low immunogenicity. Clinical trial information: NCT04630522 . [Table: see text]

Effects of walnut consumption for 2 years on older adults' bone health in the Walnuts and Healthy Aging (WAHA) trial.

Nutritional strategies to maintain bone health in aging individuals are of great interest. Given the beneficial nutrient composition of walnuts, rich in alpha-linolenic (the vegetable n-3 fatty acid) and polyphenols, their regular consumption might be a dietary option to reduce age-related bone loss. We determined whether daily walnut consumption improves bone mineral density (BMD) and circulating biomarkers of bone turnover. The Walnuts and Healthy Aging study (WAHA) is a two-center, parallel, randomized controlled trial evaluating the effect of a diet enriched with walnuts at ≈15% energy compared with a control diet for 2 years on age-related health outcomes in healthy men and women aged 63-79 years. Changes in BMD were a prespecified secondary outcome only at the Barcelona node of the trial, where 352 participants were randomized. Retention rate was 92.6%. Primary endpoints were 2-year changes in BMD at the spine and the nondominant femoral neck, determined by dual-energy X-ray absorptiometry (DXA). Secondary endpoints were 2-year changes in bone turnover biomarkers (adrenocorticotropic hormone, Dickkopf WNT signaling pathway inhibitor-1, osteoprotegerin, osteocalcin, osteopontin, sclerostin, parathyroid hormone, and fibroblast growth factor-23), which were quantified in 211 randomly selected participants. The walnut diet versus the control diet had no effect on 2-year changes in BMD at the spine (0.15% vs. 0.35%, p = 0.632) and femoral neck (-0.90% vs. -0.70%, p = 0.653), or on bone turnover biomarkers. Results were similar in participants treated or not with bone resorption inhibitors or those with or without osteoporosis/osteopenia at inclusion. Compared with the usual diet, a diet enriched with walnuts at 15% of energy for 2 years failed to improve BMD or circulating markers of bone metabolism in healthy older people.

Association between triglyceride-glucose index and femoral bone mineral density in community-dwelling, nondiabetic men and women: a NHANES analysis of 1,928 US individuals.

To determine the potential association between the triglyceride-glucose (TyG) index and bone mineral density (BMD) in community-dwelling adults without diabetes using a nationally representative database from the United States (US). Data were extracted from the National Health and Nutrition Examination Survey (NHANES) 2005-2010, 2013-2014, and 2017-2018. Men and postmenopausal women aged ≥50 years with complete data on femoral neck BMD, triglycerides, and fasting plasma glucose levels were eligible for inclusion. Participants with diabetes, history of malignancy, thyroid disease, underweight status, end-stage kidney disease, rheumatoid arthritis, estrogen/selective estrogen receptor modulators, bisphosphonate or bone resorption inhibitors, or missing dataset weight values were excluded. Univariate and multivariable logistic regression analyses were performed to determine the associations between low BMD, TyG index, and other study variables. A total of 1,844 participants (1,161 men and 683 women) were included, representing 31,517,106 community-dwelling individuals in the US. The mean age of the study population was 60.7 years old, and 26.7% of the men and 60.4% of the women had low bone density. In both males and females, the mean TyG index was 8.6. After adjusting for demographic, lifestyle, and clinical factors, no significant association was observed between TyG and femoral neck BMD among men (adjusted odds ratio [aOR] = -0.0002, 95% confidence interval [CI]: -0.02 to 0.02) and women (aBeta = 0.005, 95% CI: -0.02 to 0.04). Similarly, no significant association was observed between TyG index and the odds for low bone density among men (aOR = 1.09, 95% CI: 0.73-1.63) and women (aOR = 0.99, 95% CI: 0.49-2.01). Based on data from a large sample in the US, this study did not find an association between the TyG index and femoral neck BMD or the occurrence of low bone density in community-dwelling males and females without diabetes.

High-molecular-weight Hyaluronan Administration Inhibits Bone Resorption and Promotes Bone Formation in Young-age Osteoporosis Rats.

Osteoporosis poses a significant global health concern, affecting both the elderly and young individuals, including athletes. Despite the development of numerous antiosteoporotic drugs, addressing the unique needs of young osteoporosis patients remains challenging. This study focuses on young rats subjected to ovariectomy (OVX) to explore the impact of high-molecular-weight hyaluronan (HA) on preventing OVX-induced osteoporosis. Twenty-four rats underwent OVX, while 12 underwent sham procedures (sham control group). Among the OVX rats, half received subcutaneous injections of HA (MW: 2700 kDa) at 10 mg/kg/week into their backs (OVX-HA group), whereas the other half received saline injections (0.5 ml/week) at the same site (OVX-saline group). OVX-HA group exhibited significantly higher percentages of osteoclast surface (Oc. S/BS), osteoblast surface per bone surface (Ob. S/BS), and bone volume/tissue volume (BV/TV) compared with OVX-saline group at the same age. The proportions of Ob. S/BS and BV/TV in the OVX-HA group closely resembled those of the sham control group, whereas the proportion of Oc. S/BS in the OVX-HA group was notably higher than that in the sham control group. In summary, the administration of HA significantly mitigated bone resorption and enhanced bone formation, suggesting a crucial role for HA in the treatment of young adult osteoporosis.

Gallein increases the fibroblast growth factor 2-elicited osteoprotegerin synthesis in osteoblasts

Gallein is known as an inhibitor of Gβγ subunits, but roles of gallein in bone metabolism have not been reported. Fibroblast growth factor 2 (FGF-2) increases angiogenesis and promotes bone regeneration during the early stages of fracture healing. Osteoprotegerin (OPG) secreted by osteoblasts, binds to the receptor activator of nuclear factor-κB (RANK) ligand (RANKL) as a decoy receptor and prevents RANKL from binding to RANK, resulting in the suppression of bone resorption. Our previous report demonstrated that FGF-2 activates the phosphorylation of p38 mitogen-activated protein kinase (MAPK), stress-activated protein kinase/c-Jun N-terminal kinase (JNK), and p44/p42 MAPK in osteoblast-like MC3T3-E1 cells. Additionally, FGF-2-activated phosphorylation of p38 MAPK and JNK but not p44/p42 MAPK is positively involved in OPG synthesis in these cells. This work aimed to investigate the effects of gallein on the FGF-2-elicited OPG synthesis in osteoblast-like MC3T3-E1 cells and the mechanism. Our findings demonstrated that gallein significantly increased the FGF-2-elicited OPG synthesis in MC3T3-E1 cells. By contrast, fluorescein, gallein-like compound that does not bind Gβγ, did not affect the FGF-2-elicited OPG synthesis. Gallein significantly enhanced the FGF-2-induced OPG mRNA expression levels. Gallein did not affect the FGF-2-activated phosphorylation of p38 MAPK and p44/p42 MAPK, but significantly increased the FGF-2-activated phosphorylation of JNK, while fluorescein did not affect JNK phosphorylation. SP600125, a specific JNK inhibitor, strongly inhibited gallein-induced enhancement of FGF-2-induced OPG synthesis and mRNA expression levels. Our results indicated that gallein increases the FGF-2-induced OPG synthesis due to the JNK activation in the osteoblast.

Sclerostin blockade inhibits bone resorption through PDGF receptor signaling in osteoblast lineage cells.

While sclerostin-neutralizing antibodies (Scl-Abs) transiently stimulate bone formation by activating Wnt signaling in osteoblast lineage cells, they exert sustained inhibition of bone resorption, suggesting an alternate signaling pathway by which Scl-Abs control osteoclast activity. Since sclerostin can activate platelet-derived growth factor receptors (PDGFRs) in osteoblast lineage cells in vitro and PDGFR signaling in these cells induces bone resorption through M-CSF secretion, we hypothesized that the prolonged anticatabolic effect of Scl-Abs could result from PDGFR inhibition. We show here that inhibition of PDGFR signaling in osteoblast lineage cells is sufficient and necessary to mediate prolonged Scl-Ab effects on M-CSF secretion and osteoclast activity in mice. Indeed, sclerostin coactivates PDGFRs independently of Wnt/β-catenin signaling inhibition, by forming a ternary complex with LRP6 and PDGFRs in preosteoblasts. In turn, Scl-Ab prevents sclerostin-mediated coactivation of PDGFR signaling and consequent M-CSF upregulation in preosteoblast cultures, thereby inhibiting osteoclast activity in preosteoblast/osteoclast coculture assays. These results provide a potential mechanism explaining the dissociation between anabolic and antiresorptive effects of long-term Scl-Ab.

Effect of hyperoside on osteoporosis in ovariectomized mice through estrogen receptor α/ITG β3 signaling pathway

Osteoporosis is a highly prevalent bone metabolic disease in menopause due to estrogen deficiency. Hyperoside is a main compound in Semen cuscutae. Our team previously reported that Semen cuscutae has anti osteoporosis effect on ovariectomized mice by inhibiting bone resorption of osteoclasts. However, it is still unclear whether hyperoside affects osteoclast differentiation and bone resorption, and whether its anti-osteoporosis effect is related to an estrogen-like effect. This study investigates the potential mechanism of hyperoside's anti-osteoporotic effect by examining its impact on osteoclast differentiation and its relationship with the estrogen receptor. DXA, Micro-CT, TRAP staining, HE, and ELISA were used to assess the impact of hyperoside on OVX-induced osteoporosis. The effect of hyperoside on octeoclast differentiation was evaluated using TRAP activity assay, TRAP staining, F-actin staining. The activation of the estrogen receptor by hyperoside and its relationship with osteoclast differentiation were detected using dual-luciferase reporter assay and estrogen receptor antagonists. Our findings revealed that hyperoside (20-80mg/kg) protect against OVX-induced osteoporosis, including increasing BMD and BMC and improving bone microstructure. Hyperoside inhibited osteoclast differentiation in a concentration dependent manner, whereas estrogen receptor α antagonists reversed its inhibitory effect osteoclast differentiation. Western blot results suggested that hyperoside inhibited TRAP, RANKL, c-Fos and ITG β3 protein expression in osteoclast or femoral bone marrow of ovariectomized mice. Our findings suggest that hyperoside inhibits osteoclast differentiation and protects OVX-induced osteoporosis through the ERα/ITGβ3 signaling pathway.

Unveiling the role of hypoxia-inducible factor 2alpha in osteoporosis: Implications for bone health.

Osteoporosis (OP) has become a major public health problem worldwide. Most OP treatments are based on the inhibition of bone resorption, and it is necessary to identify additional treatments aimed at enhancing osteogenesis. In the bone marrow (BM) niche, bone mesenchymal stem cells (BMSCs) are exposed to a hypoxic environment. Recently, a few studies have demonstrated that hypoxia-inducible factor 2alpha (HIF-2α) is involved in BMSC osteogenic differentiation, but the molecular mechanism involved has not been determined. To investigate the effect of HIF-2α on the osteogenic and adipogenic differentiation of BMSCs and the hematopoietic function of hematopoietic stem cells (HSCs) in the BM niche on the progression of OP. Mice with BMSC-specific HIF-2α knockout (Prx1-Cre;Hif-2αfl/fl mice) were used for in vivo experiments. Bone quantification was performed on mice of two genotypes with three interventions: Bilateral ovariectomy, semilethal irradiation, and dexamethasone treatment. Moreover, the hematopoietic function of HSCs in the BM niche was compared between the two mouse genotypes. In vitro, the HIF-2α agonist roxadustat and the HIF-2α inhibitor PT2399 were used to investigate the function of HIF-2α in BMSC osteogenic and adipogenic differentiation. Finally, we investigated the effect of HIF-2α on BMSCs via treatment with the mechanistic target of rapamycin (mTOR) agonist MHY1485 and the mTOR inhibitor rapamycin. The quantitative index determined by microcomputed tomography indicated that the femoral bone density of Prx1-Cre;Hif-2αfl/fl mice was lower than that of Hif-2αfl/fl mice under the three intervention conditions. In vitro, Hif-2αfl/fl mouse BMSCs were cultured and treated with the HIF-2α agonist roxadustat, and after 7 d of BMSC adipogenic differentiation, the oil red O staining intensity and mRNA expression levels of adipogenesis-related genes in BMSCs treated with roxadustat were decreased; in addition, after 14 d of osteogenic differentiation, BMSCs treated with roxadustat exhibited increased expression of osteogenesis-related genes. The opposite effects were shown for mouse BMSCs treated with the HIF-2α inhibitor PT2399. The mTOR inhibitor rapamycin was used to confirm that HIF-2α regulated BMSC osteogenic and adipogenic differentiation by inhibiting the mTOR pathway. Consequently, there was no significant difference in the hematopoietic function of HSCs between Prx1-Cre;Hif-2αfl/fl and Hif-2αfl/fl mice. Our study showed that inhibition of HIF-2α decreases bone mass by inhibiting the osteogenic differentiation and increasing the adipogenic differentiation of BMSCs through inhibition of mTOR signaling in the BM niche.