Modulating Bone Resorption and Bone Formation in Opposite Directions in the Treatment of Postmenopausal Osteoporosis

Molecular mechanism of mitochondrial autophagy mediating impaired energy metabolism leading to osteoporosis

Osteoporosis (OP) is a bone metabolic disease caused by decreased bone mass leading to destruction of bone microstructure. Treatment of OP is characterized by a lifelong nature, causing extreme financial and psychological burdens to patients. Hormonal abnormalities, cellular autophagy, Ferroptosis, and oxidative stress are all part of the intricate and varied pathophysiology of OP. Recent research has revealed that mitochondrial dysfunction is a significant factor in the onset and progression of OP. By regulating bone marrow mesenchymal stem cell differentiation through various signaling pathways and cytokines, abnormal mitochondrial energy metabolism brought on by oxidative stress processes impacts osteoblast and osteoclast proliferation and differentiation, causing an imbalance in bone metabolism that ultimately results in OP. Therefore, one possible method to prevent and manage OP may be to use mitochondria as a carrier to trigger osteogenic differentiation of bone marrow mesenchymal stem cells from mitochondrial energy consumption, oxidative stress, autophagy, and osteoclast death. In order to offer some theoretical references and therapeutic approaches for the clinical prevention and treatment of OP, we will examine the pathophysiology of OP from mitochondrial dysfunction in this work.

COPB1 deficiency triggers osteoporosis with elevated iron stores by inducing osteoblast ferroptosis

Background

Osteoporosis (OP) is a systemic bone metabolic disease that results from an imbalance between bone formation and bone resorption. The accumulation of iron has been identified as an independent risk factor for osteoporosis. Ferroptosis, a novel form of programmed cell death, is driven by iron-dependent lipid peroxidation. Nevertheless, the precise role of ferroptosis in iron accumulation-induced osteoporosis remains uncertain.

Methods

We utilized proteomics and ELISA to screen key regulatory molecules related to iron accumulation in osteoporosis populations. HE staining was used to assess osteocyte changes in Hamp knockout (KO) iron accumulation mouse models. Western Blot, qPCR, ALP staining, and Alizarin Red staining were employed to explore the effects of siRNA-mediated gene knockdown on osteogenic differentiation in the MC3T3 cell line. ELISA, micro-CT, von Kossa staining, toluidine blue staining, TRAP staining, and calcein analysis were used to study the bone phenotype of conditional gene knockout mice. RNA-seq, endoplasmic reticulum activity probes, transmission electron microscopy (TEM), Western Blot, co-immunoprecipitation (Co-IP), flow cytometry, and ChIP-seq were employed to investigate the regulatory mechanisms of the target gene in osteogenic differentiation. OVX and Hamp KO mice were used to establish osteoporosis models, and AAV-mediated overexpression was employed to explore the intervention effects of the target gene on osteoporosis.

Results

The experiments demonstrate that iron accumulation can lead to changes in COPB1 expression levels in bone tissue. Cellular and animal experiments revealed that COPB1 deficiency reduces the osteogenic ability of osteoblasts. Transcriptome analysis and phenotypic experiments revealed that COPB1 deficiency induces ferroptosis and endoplasmic reticulum stress in cells. Further investigation confirmed that COPB1 plays a key role in endoplasmic reticulum stress by inhibits SLC7A11 transcription via ATF6. This reduces cystine uptake, ultimately inducing ferroptosis. Overexpression of COPB1 can restore osteogenic function in both cells and mice.

Conclusion

This study elucidated the essential role of COPB1 in maintaining bone homeostasis and highlights it as a potential therapeutic target for treating iron accumulation-related osteoporosis.

The translational potential of this article

Our data elucidate the critical role of COPB1 in maintaining bone homeostasis and demonstrate that COPB1 can directly promote bone formation, making it a potential therapeutic target for the future treatment of osteoporosis.

"Betaone" barley water extract suppresses ovariectomy-induced osteoporosis in vivo and RANKL-induced osteoclast differentiation in vitro

Betaone is a variety of barley developed by the Korea Rural Development Administration. This study investigated the anti-osteoporosis effects of Betaone barley water extract (B1W) on ovariectomy (OVX)-induced bone loss in mice. To elucidate its mechanism, the effect of B1W on osteoclasts was assessed by measuring the protein expression of nuclear factor-activated T cells c1 (NFATc1), the expression of genes involved in osteoclast differentiation, and bone pit assays. B1W (300 mg/kg/day) significantly increased bone mineral density and bone volume fraction, but decreased trabecular separation compared to the OVX group. B1W also showed a trend towards decreasing serum C-telopeptide of collagen type 1 levels in OVX mice. Additionally, B1W reduced the expression of NFATc1 and downregulated the mRNA expression levels of various marker genes such as c-Fos, tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), dendritic cell-specific transmembrane protein (DC-STAMP), and osteoclast-associated Ig-like receptor (OSCAR). B1W reduced the osteoclast activity in the receptor activator of nuclear factor-κB ligand (RANKL)-treated osteoclasts by inhibiting the mitogen-activated protein kinase (MAPK) pathway. Based on the results, B1W can be considered a useful candidate for a therapeutic agent for treating conditions of bone loss and could also be used as an ingredient in health supplements.

Therapeutic Efficacy of Medicinal Plants with Allopathic Medicine in Musculoskeletal Diseases

Musculoskeletal diseases encompass a diverse array of disorders affecting the muscles, bones, joints, and connective tissues, leading to significant impairments in mobility, function, and quality of life. Affecting over 1.3 billion individuals globally, musculoskeletal diseases represent a major source of disability and economic burden. Conventional treatment modalities, including pharmacological interventions and surgical procedures, are frequently limited by adverse side effects, prolonged recovery periods, and patient dissatisfaction, particularly when focused solely on symptom management. In response, complementary and alternative medicine, particularly the use of medicinal plants, has garnered increasing interest to enhance the management of musculoskeletal diseases. Medicinal plants possess a wide spectrum of pharmacologically active compounds with anti-inflammatory, analgesic, and antioxidant properties, making them promising adjuncts to conventional therapies. This review critically evaluates the potential synergy between medicinal plants and allopathic medicine for the management of musculoskeletal diseases, with an emphasis on integrated therapy that combines both modalities. Specifically, a critical discussion is presented on how medicinal plants with scientifically supported pharmacological properties can augment the therapeutic efficacy of conventional medications, reduce their doses, and mitigate adverse effects. Furthermore, the challenges associated with incorporating herbal medicine into established healthcare systems are discussed, including the need for rigorous clinical validation, standardization, and regulatory frameworks. Overall, the article underscores the potential of integrated therapeutic approaches to improve clinical outcomes, enhance patient well-being, and establish a more sustainable model for the treatment of musculoskeletal diseases.

Contribution of macrophage polarization in bone metabolism: A literature review

Macrophage polarization divides macrophages into two main cell subpopulations, classically and alternatively activated macrophages (M1 and M2, respectively). M1 polarization promotes osteoclastogenesis, while M2 polarization promotes osteogenesis. The physiological homeostasis of bone metabolism involves a high dynamic balance between osteoclastic-mediated bone resorption and formation. Reportedly, M1/M2 imbalance causes the onset and persistence of inflammation-related bone diseases. Therefore, understanding the research advances in functions and roles of macrophages in such diseases will provide substantial guidance for improved treatment of bone diseases. In this review, we underscore and summarize the research advances in macrophage polarization, and bone-related diseases, such as rheumatoid arthritis, osteoarthritis, and osteoporosis, over the last 5 years. Our findings showed that targeting macrophages and balancing macrophage polarization can effectively reduce inflammation and decrease bone destruction while promoting bone formation and vascular repair. These results indicate that regulating macrophage and macrophage polarization to restore homeostasis is a prospective approach for curing bone-related diseases.

Puerarin alleviates osteoporosis in rats by targeting the JAK2/STAT3 signaling pathway

Osteoporosis (OP) is a common chronic progressive bone disease that increases fracture risk in postmenopausal women. Research suggests that puerarin (Pue) may be an effective treatment for OP. This study examined the effects and underlying mechanisms of Pue in treating postmenopausal osteoporosis (PMOP) in rats. Sprague-Dawley (SD) rats underwent bilateral ovariectomy to simulate PMOP and were then treated with subcutaneous injections of Pue. Bone mineral density (BMD) was measured using a bone densitometer. Micro-CT scans assessed femur bone structure and various parameters were calculated: bone volume fraction (BV/TV), bone surface density (BS/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), and bone surface area-to-bone volume ratio (BS/BV). Hematoxylin-eosin (HE) staining was employed to observe femoral tissue pathology. Serum levels of bone formation metabolism-related markers-osteocalcin (OC), bone alkaline phosphatase (BALP), and procollagen type I N-terminal propeptide (PINP)-were measured via enzyme-linked immunosorbent assay (ELISA). The protein expression levels of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in bone tissue were evaluated using Western blotting assay. The results showed improved bone density and reduced bone loss in rats treated with Pue. There were also significant increases in serum levels of OC and BALP, indicating enhanced osteogenesis. Furthermore, there was a decrease in activation of the JAK2/STAT3 pathway in femoral tissue, suggesting a pathway inhibition. These findings indicate that Pue may combat osteoporosis by promoting osteogenesis and inhibiting activation of the JAK2/STAT3 pathway activation.

Long-term second-generation antipsychotics decreases bone formation and resorption in male patients with schizophrenia

RATIONALE

Patients with schizophrenia with second-generation antipsychotics (SGAs) treatment have shown an increased risk of bone fragility and susceptibility to fracture; however, it is still unclear whether this risk is derived from the effect of antipsychotics on balance of bone metabolism.

OBJECTIVES

We investigated the changes of two bone turnover biomarkers (BTMs) concentrations in people with schizophrenia receiving SGAs: procollagen type I aminoterminal propeptide (PINP) and C-terminal telopeptide of type I collagen (CTX-1) as BTMs of osteogenesis and bone resorption, respectively, to explore how antipsychotics contribute to bone fragility.

METHODS

We recruited 59 Chinese male patients with schizophrenia (32 drug-naïve first-episode (DNFE) patients and 27 chronic patients) to undergo 8 weeks SGAs treatment. Fasting peripheral blood samples of pre- and posttreatment were collected, plasma levels of PINP and CTX-1 were measured.

RESULTS

The interaction effects of group and time on PINP and CTX-1 concentrations were found (P = .016 and P = .008). There was a significant decrease for both BTMs concentrations of the posttreatment compared to the pretreatment (P<.001 and P = .003). Chronic patients had significantly higher changes of BTMs concentrations compared to DNFE patients (P = .048 and P = .024). There was a positive correlation of the two BTMs of pretreatment with disease course in DNFE group (r = .37, P = .039;r = .38, P = .035) and a negative correlation of PINP of pretreatment with age in the chronic group (r=-.40, P = .039).

CONCLUSION

Long-term SGAs medication inhibited osteogenesis in a dose- and time-dependent manner and damaged the balance of bone formation and bone resorption.

Perturbations in gut microbiota composition in osteoporosis: a systematic review and meta-analysis

INTRODUCTION

Osteoporosis (OP) is a chronic bone metabolic disease, which causes a great social and economic burden. The gut microbiota (GM) has become a recent topic of interest in the role of many disease states. Changes in the GM are correlated with the maintenance of bone mass and bone quality. However, research results in this field remain highly controversial. We performed a mate-analysis to explore and compare the alterations of GM in OP patients.

MATERIALS AND METHODS

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), we comprehensively searched the databases of PubMed, Web of Science, Embase, Cochrane Library, CNKI, VIP, CBM, and Wanfang. In addition, we applied the Stata 17.0 software for data analysis. Bias controls were evaluated with the Newcastle-Ottawa scale (NOS), funnel plot analysis, and Egger's and Begg's tests.

RESULTS

This research ultimately considered 16 studies, which included the fecal GM data of 2340 people (664 with OP and 1676 healthy controls). The pooled estimate showed an increase of borderline significance on ACE index in patients with OP compared with control participants (SMD = 1.05; 95% CI 0.00-2.10; P = 0.05). There were no significant differences in Chao1, Shannon and Simpson indices. At the phylum level, no significant differences were observed between the OP patients and HCs in the overall analysis. At the genus level, the relative abundance of Blautia presented a decrease of borderline significance between OP and the control group (SMD = - 0.32, 95% CI - 0.65 to - 0.00, P = 0.05).

CONCLUSION

This systematic review and meta-analysis suggests that patients with OP may exhibit dysbiosis in their gut microbiota, characterized by a reduction in certain anti-inflammatory butyrate-producing bacteria and an enrichment of pro-inflammatory bacterial populations.

E3 ubiquitin ligases: key regulators of osteogenesis and potential therapeutic targets for bone disorders

Ubiquitination is a crucial post-translational modification of proteins that mediates the degradation or functional regulation of specific proteins. This process participates in various biological processes such as cell growth, development, and signal transduction. E3 ubiquitin ligases play both positive and negative regulatory roles in osteogenesis and differentiation by ubiquitination-mediated degradation or stabilization of transcription factors, signaling molecules, and cytoskeletal proteins. These activities affect the proliferation, differentiation, survival, and bone formation of osteoblasts (OBs). In recent years, advances in genomics, transcriptomics, and proteomics have led to a deeper understanding of the classification, function, and mechanisms of action of E3 ubiquitin ligases. This understanding provides new insights and approaches for revealing the molecular regulatory mechanisms of bone formation and identifying therapeutic targets for bone metabolic diseases. This review discusses the research progress and significance of the positive and negative regulatory roles and mechanisms of E3 ubiquitin ligases in the process of osteogenic differentiation. Additionally, the review highlights the role of E3 ubiquitin ligases in bone-related diseases. A thorough understanding of the role and mechanisms of E3 ubiquitin ligases in osteogenic differentiation could provide promising therapeutic targets for bone tissue engineering based on stem cells.

Extracellular Vesicles from Human Adipose Tissue-Derived Mesenchymal Stem Cells Suppress RANKL-Induced Osteoclast Differentiation via miR122-5p

Researchers are increasingly interested in cell therapy using mesenchymal stem cells (MSCs) as an alternative remedy for osteoporosis, with fewer side effects. Thus, we isolated and characterized extracellular vesicles (EVs) from human adipose tissue-derived MSCs (hMSCs) and investigated their inhibitory effects on RANKL-induced osteoclast differentiation. Purified EVs were collected from the supernatant of hMSCs by tangential flow filtration. Characterization of EVs included typical evaluation of the size and concentration of EVs by nanoparticle tracking analysis and morphology analysis using transmission electron microscopy. hMSC-EVs inhibited RANKL-induced differentiation of bone marrow-derived macrophages (BMDMs) into osteoclasts in a dose-dependent manner. F-actin ring formation and bone resorption were also reduced by EV treatment of osteoclasts. In addition, EVs decreased RANKL-induced phosphorylation of p38 and JNK and expression of osteoclastogenesis-related genes in BMDMs treated with RANKL. To elucidate which part of the hMSC-EVs plays a role in the inhibition of osteoclast differentiation, we analyzed miRNA profiles in hMSC-EVs. The results showed that has-miR122-5p was present at significantly high read counts. Overexpression of miR122-5p in BMDMs significantly inhibited RANKL-induced osteoclast differentiation and induced defects in F-actin ring formation and bone resorption. Our results also revealed that RANKL-induced phosphorylation of p38 and JNK and osteoclast-specific gene expression was decreased by miR122-5p transfection, which was consistent with the results of hMSC-EVs. These findings suggest that hMSC-EVs containing miR122-5p inhibit RANKL-induced osteoclast differentiation via the downregulation of molecular mechanisms and could be a preventive candidate for destructive bone diseases.

Romosozumab versus parathyroid hormone receptor agonists: which osteoanabolic to choose and when?

Osteoanabolic agents are used as a first line treatment in patients at high fracture risk. The PTH receptor 1 (PTH1R) agonists teriparatide (TPTD) and abaloparatide (ABL) increase bone formation, bone mineral density (BMD), and bone strength by activating PTH receptors on osteoblasts. Romosozumab (ROMO), a humanized monoclonal antibody against sclerostin, dramatically but transiently stimulates bone formation and persistently reduces bone resorption. Osteoanabolic agents increase BMD and bone strength while being more effective than antiresorptives in reducing fracture risk in postmenopausal women. However, direct comparisons of the antifracture benefits of osteoanabolic therapies are limited. In a direct comparison of TPTD and ABL, the latter resulted in greater BMD increases at the hip. While no differences in vertebral or non-vertebral fracture risk were observed between the two drugs, ABL led to a greater reduction of major osteoporotic fractures. Adverse event profiles were similar between the two agents except for hypercalcemia, which occurred more often with TPTD. No direct comparisons of fracture risk reduction between ROMO and the PTH1R agonists exist. Individual studies have shown greater increases in BMD and bone strength with ROMO compared with TPTD in treatment-naive women and in women previously treated with bisphosphonates. Some safety aspects, such as a history of tumor precluding the use of PTH1R agonists, and a history of major cardiovascular events precluding the use of ROMO, should also be considered when choosing between these agents. Finally, convenience of administration, reimbursement by national health systems and length of clinical experience may influence patient choice.

Cirsilineol inhibits RANKL-induced osteoclast activity and ovariectomy-induced bone loss via NF-κb/ERK/p38 signaling pathways

BACKGROUND

Postmenopausal osteoporosis is a chronic metabolic bone disease caused by excessive osteoclast formation and function. Targeting osteoclast differentiation and activity can modulate bone resorption and alleviate osteoporosis. Cirsilineol, an active constituent of Vestita Wall, has shown numerous biological activities and has been used to treat many metabolic diseases. However, whether cirsilineol inhibits osteoclast activity and prevents postmenopausal osteoporosis still remain unknown.

MATERIALS AND METHODS

Primary bone marrow macrophages (BMMs) and RAW264.7 cells were used. Osteoclast activity was measured by TRAP staining, F-actin staining, and bone resorption assay after BMMs were treated with cirsilineol at concentrations of 0, 1, 2.5 and 5 µM. RT-PCR and western blotting were performed to evaluate the expression of osteoclast-related genes. In addition, female C57BL/6 mice underwent OVX surgery and were treated with cirsilineol (20 mg/kg) to demonstrate the effect of cirsilineol on osteoporosis.

RESULTS

Cirsilineol significantly inhibited receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclast differentiation in a concentration- and time-dependent manner, respectively. Additionally, cirsilineol inhibited F-actin ring formation, thus reducing the activation of bone resorption ability. Cirsilineol suppressed the expression of osteoclast-related genes and proteins via blocking nuclear factor (NF)-κb, ERK, and p38 signaling cascades. More importantly, cirsilineol treatment in mice with osteoporosis alleviated osteoclasts hyperactivation and bone mass loss caused by estrogen depletion.

CONCLUSION

In this study, the protective effect of cirsilineol on osteoporosis has been investigated for the first time. In conclusion, our findings prove the inhibitory effect of cirsilineol on osteoclast activity via NF-κb/ERK/p38 signaling pathways and strongapplication of cirsilineol can be proposed as a potential therapeutic strategy.

[Zinc finger protein-36 deficiency inhibits osteogenic differentiation of mouse bone marrow-derived mesenchymal stem cells and preosteoblasts by activating the ERK/MAPK pathway]

OBJECTIVE

To explore the role of zinc finger protein 36(ZFP36) in regulating osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) and preosteoblasts.

METHODS

ZFP36 expression was observed in primary mouse BMSCs and mouse preosteoblasts (MC3T3-E1 cells) during induced osteogenic differentiation. Zfp36-deficient cell models were constructed in the two cells using RNA interference technique and the changes in differentiation capacities of the transfected cells into osteoblasts were observed. Transcriptome sequencing was used to investigate the potential mechanisms of ZFP36 for regulating osteoblast differentiation of the two cells. U0126, a ERK/MAPK signal suppressor, was used to verify the regulatory mechanism of Zfp36 in osteogenic differentiation of Zfp36-deficient cells.

RESULTS

During the 14-day induction of osteogenic differentiation, both mouse BMSCs and MC3T3-E1 cells exhibited increased expression of ZFP36, and its mRNA expression reached the peak level on Day 7(P < 0.0001). The Zfp36-deficient cell models showed reduced intensity of alkaline phosphatase (ALP) staining and alizarin red staining with significantly lowered expressions of the osteogenic marker genes including Alpl, Sp7, Bglap and Ibsp (P < 0.01). Transcriptome sequencing verified the reduction of bone mineralization-related gene expressions in Zfp36-deficient cells and indicated the involvement of ERK signaling in the potential regulatory mechanism of Zfp36. Immunoblotting showed that pERK protein expression increased significantly in Zfp36-deficient cells compared with the control cells. In Zfp36-deficient MC3T3-E1 cells, inhibition of activated ERK/MAPK signaling with U0126 resulted in obviously enhanced ALP staining and significantly increased expressions of osteoblast differentiation markers Runx2 and Bglap (P < 0.05).

CONCLUSIONS

ZFP36 is involved in the regulation of osteoblast differentiation of mouse BMSCs and preosteoblasts, and ZFP36 deficiency causes inhibition of osteoblast differentiation of the cells by activating the ERK/MAPK signaling pathway.

A novel PDIA3/FTO/USP20 positive feedback regulatory loop induces osteogenic differentiation of preosteoblast in osteoporosis

Osteoporosis is a chronic skeletal disease and the major source of risk for fractures in aged people. It is urgent to investigate the mechanism regulating osteoporosis for developing potential treatment and prevention strategies. Osteogenic differentiation of preosteoblast enhances bone formation, which might be a promising strategy for treatment and prevention of osteoporosis. Protein disulfide isomerase family A, member 3 (PDIA3) could induce bone formation, yet the role of PDIA3 in osteogenic differentiation of preosteoblast remains unknown. In this study, m6 A RNA methylation was detected by methylated RNA immunoprecipitation (MeRIP), while mRNA stability was identified by RNA decay assay. Besides, protein-protein interaction and protein phosphorylation were determined using co-immunoprecipitation (Co-IP). Herein, results revealed that PDIA3 promoted osteogenic differentiation of preosteoblast MC3T3-E1. Besides, PDIA3 mRNA methylation was suppressed by FTO alpha-ketoglutarate dependent dioxygenase (FTO) as RNA methylation reduced PDIA3 mRNA stability during osteogenic differentiation of MC3T3-E1 cells. Moreover, ubiquitin specific peptidase 20 (USP20) improved FTO level through inhibiting FTO degradation while PDIA3 increased FTO level by enhancing USP20 phosphorylation during osteogenic differentiation of MC3T3-E1 cells, suggesting a positive feedback regulatory loop between PDIA3 and FTO. In summary, these findings indicated the mechanism of PDIA3 regulating osteogenic differentiation of preosteoblast and provided potential therapeutic targets for osteoporosis.

Ca-AlN MOFs-loaded chitosan/gelatin scaffolds; a dual-delivery system for bone tissue engineering applications

Creating a scaffold for bone tissue engineering that is bioactive and capable of acting as a local-dual delivery system, releasing bioactive molecules and regulating the bone remodeling process to achieve balanced bone resorption and formation, is a significant challenge. The objective of this research is to create a composite scaffold using chitosan/gelatin (CHS/Gel) and the calcium (Ca)-alendronate (ALN) metal-organic frameworks (MOFs). The scaffold will act as a dual-delivery system, releasing Ca ions and ALN to regulate bone formation. Ca-ALN MOF nanoparticles (NPs) were prepared in mild conditions and studied by FTIR, XRD, FESEM, and TGA. Ca-ALN NPs-loaded CHS/Gel scaffolds were opportunely fabricated through freeze-drying approach. Physicochemical features of the scaffolds after incorporating NPs equated by CHS/Gel scaffold changed, therefore, the attendance of NPs caused a decreasing porosity, decreased swelling, and low rate of degradation. The release profile results showed that the NPs-loaded CHS/Gel scaffolds were able to simultaneously release ALN and Ca ions due to the decomposition of NPs. Additionally, the loading of NPs in the CHS/Gel scaffold led to an increment in alkaline phosphatase (ALP) activity and the quantity of deposited Ca along with osteogenesis gene markers. These findings suggest that the NPs-loaded CHS/Gel scaffold has the potential to enhance the differentiation of human adipose tissue-derived mesenchymal stem cells, making it a promising approach for bone repair.

Koumine inhibits RANKL-induced ubiquitination and NF-κB activation to prevent ovariectomy and aging-induced bone loss

Osteoporosis (OP) is a bone remodeling disease characterized by an imbalance between bone resorption and formation. Osteoclasts are the primary therapeutic targets for treating bone destruction. Koumine (KM), the most bioactive component in Gelsemium alkaloids, exhibits antitumor, immunosuppressive, anti-inflammatory, and analgesic properties. However, the effects of bone loss have not been well studied. This study conducted in vitro and in vivo verification experiments on KM. The results showed that KM inhibited bone resorption and tartrate-resistant acid phosphatase positive (TRAP+) osteoclasts development by mature osteoclasts in a dose-dependent manner. Moreover, KM prevented OVX-induced OP in vivo and potentially inhibited ubiquitination, a process closely related to various biological activities, including protein interaction, transcription, and transmembrane signal transduction regulation, especially within the nuclear factor-κB (NF-κB) pathway. Previous studies have demonstrated that several proteins ubiquitination promotes osteoclastogenesis, our study indicated that KM inhibits early NF-κB activation and receptor activator of NF-κB ligand induced ubiquitination, a critical factor in osteoclast differentiation. In conclusion, our research suggests that KM holds potential as an effective therapeutic agent for OP.

Modulation of the vitamin D/vitamin D receptor system in osteoporosis pathogenesis: insights and therapeutic approaches

Osteoporosis is a prevalent bone disorder characterized by low bone mineral density (BMD) and deteriorated bone microarchitecture, leading to an increased risk of fractures. Vitamin D (VD), an essential nutrient for skeletal health, plays a vital role in maintaining bone homeostasis. The biological effects of VD are primarily mediated through the vitamin D receptor (VDR), a nuclear receptor that regulates the transcription of target genes involved in calcium and phosphate metabolism, bone mineralization, and bone remodeling. In this review article, we conduct a thorough literature search of the PubMed and EMBASE databases, spanning from January 2000 to September 2023. Utilizing the keywords "vitamin D," "vitamin D receptor," "osteoporosis," and "therapy," we aim to provide an exhaustive overview of the role of the VD/VDR system in osteoporosis pathogenesis, highlighting the most recent findings in this field. We explore the molecular mechanisms underlying VDR's effects on bone cells, including osteoblasts and osteoclasts, and discuss the impact of VDR polymorphisms on BMD and fracture risk. Additionally, we examine the interplay between VDR and other factors, such as hormonal regulation, genetic variants, and epigenetic modifications, that contribute to osteoporosis susceptibility. The therapeutic implications of targeting the VDR pathway for osteoporosis management are also discussed. By bringing together these diverse aspects, this review enhances our understanding of the VD/VDR system's critical role in the pathogenesis of osteoporosis and highlights its significance as a potential therapeutic target.

Nano-residronate loaded κ-carrageenan-based injectable hydrogels for bone tissue regeneration

Bone tissue possesses intrinsic regenerative capabilities to address deformities; however, its ability to repair defects caused by severe fractures, tumor resections, osteoporosis, joint arthroplasties, and surgical reconsiderations can be hindered. To address this limitation, bone tissue engineering has emerged as a promising approach for bone repair and regeneration, particularly for large-scale bone defects. In this study, an injectable hydrogel based on kappa-carrageenan-co-N-isopropyl acrylamide (κC-co-NIPAAM) was synthesized using free radical polymerization and the antisolvent evaporation technique. The κC-co-NIPAAM hydrogel's cross-linked structure was confirmed using Fourier transform infrared spectra (FTIR) and nuclear magnetic resonance (1H NMR). The hydrogel's thermal stability and morphological behavior were assessed using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), respectively. Swelling and in vitro drug release studies were conducted at varying pH and temperatures, with minimal swelling and release observed at low pH (1.2) and 25 °C, while maximum swelling and release occurred at pH 7.4 and 37oC. Cytocompatibility analysis revealed that the κC-co-NIPAAM hydrogels were biocompatible, and hematoxylin and eosin (H&E) staining demonstrated their potential for tissue regeneration and enhanced bone repair compared to other experimental groups. Notably, digital x-ray examination using an in vivo bone defect model showed that the κC-co-NIPAAM hydrogel significantly improved bone regeneration, making it a promising candidate for bone defects.

Extracellular vesicles from bone marrow mesenchymal stem cells alleviate osteoporosis in mice through USP7-mediated YAP1 protein stability and the Wnt/β-catenin pathway

Mesenchymal stem cells (MSCs) and their derived extracellular vesicles (EVs) have emerged as promising tools for promoting bone regeneration. This study investigates the functions of EVs derived from bone marrow-derived MSCs (BMSCs) in osteoporosis (OP) and the molecular mechanism. EVs were isolated from primary BMSCs in mice. A mouse model with OP was induced by ovariectomy. Treatment with EVs restored bone mass and strength, attenuated trabecular bone loss and cartilage damage, and increased osteogenesis while suppressing osteoclastogenesis in ovariectomized mice. In vitro, the EVs treatment improved the osteogenic differentiation of MC-3T3 while inhibiting osteoclastic differentiation of RAW264.7 cells. Microarray analysis revealed a significant upregulation of ubiquitin specific peptidase 7 (USP7) expression in mouse bone tissues following EV treatment. USP7 was found to interact with Yes1 associated transcriptional regulator (YAP1) and stabilize YAP1 protein through deubiquitination modification. YAP1-related genes were enriched in the Wnt/β-catenin signaling, and overexpression of YAP1 promoted the nuclear translocation of β-catenin. Functional experiments underscored the critical role of maintaining USP7, YAP1, and β-catenin levels in the pro-osteogenic and anti-osteoclastogenic properties of the BMSC-EVs. In conclusion, this study demonstrates that USP7, delivered by BMSC-derived EVs, stabilizes YAP1 protein, thereby ameliorating bone formation in OP through the Wnt/β-catenin activation.

The role of E3 ubiquitin ligases in bone homeostasis and related diseases

The ubiquitin-proteasome system (UPS) dedicates to degrade intracellular proteins to modulate demic homeostasis and functions of organisms. These enzymatic cascades mark and modifies target proteins diversly through covalently binding ubiquitin molecules. In the UPS, E3 ubiquitin ligases are the crucial constituents by the advantage of recognizing and presenting proteins to proteasomes for proteolysis. As the major regulators of protein homeostasis, E3 ligases are indispensable to proper cell manners in diverse systems, and they are well described in physiological bone growth and bone metabolism. Pathologically, classic bone-related diseases such as metabolic bone diseases, arthritis, bone neoplasms and bone metastasis of the tumor, etc., were also depicted in a UPS-dependent manner. Therefore, skeletal system is versatilely regulated by UPS and it is worthy to summarize the underlying mechanism. Furthermore, based on the current status of treatment, normal or pathological osteogenesis and tumorigenesis elaborated in this review highlight the clinical significance of UPS research. As a strategy possibly remedies the limitations of UPS treatment, emerging PROTAC was described comprehensively to illustrate its potential in clinical application. Altogether, the purpose of this review aims to provide more evidence for exploiting novel therapeutic strategies based on UPS for bone associated diseases.

Association of the composite dietary antioxidant index with bone mineral density in the United States general population: data from NHANES 2005-2010

INTRODUCTION

There is evidence that individual antioxidants may increase bone mineral density (BMD) in patients with low BMD. However, the association between overall dietary antioxidant intake and BMD is unclear. The objective of this study was to examine how overall dietary antioxidant intake is related to BMD.

MATERIALS AND METHODS

A total of 14,069 people participated in the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2010. Dietary Antioxidant Index (DAI) was calculated from the intake of vitamins A, C, E, zinc, selenium, and magnesium, which indicates a nutritional tool to assess the overall antioxidant properties of the diet. The correlation between the Composite Dietary Antioxidant Index (CDAI) and BMD was examined using multivariate logistic regression models. In addition to fitting smoothing curves, we fitted generalized additive models as well. Furthermore, to ensure data stability and avoid confounding factors, subgroup analysis was also conducted on gender and body mass index (BMI).

RESULTS

A significant association was demonstrated by the study between CDAI and total spine BMD (β = 0.001, 95% CI 0-0.001, P = 0.00039). And just like that, CDAI was positively correlated with femoral neck (β = 0.003, 95% CI 0.003-0.004, P < 0.00001) and trochanter (β = 0.004, 95% CI 0.003-0.004, P < 0.00001). In the gender subgroup analysis, CDAI maintained a strong positive correlation with femoral neck and trochanter BMD in males and females. Nevertheless, the link with total spine BMD was only observed in males. In addition, in the subgroup analysis stratified by BMI, CDAI showed a significantly positive relation to BMD of the femoral neck and trochanter in each group. However, the significant relationship between CDAI and BMD of the total spine was only maintained when BMI was above 30 kg/m2.

CONCLUSION

This study found that CDAI correlated positively with femoral neck, trochanter, and total spine BMD. This suggests that intake of a diet rich in antioxidants can reduce the risk of low bone mass and osteoporosis.

Targeting proteostasis network in osteoporosis: Pathological mechanisms and therapeutic implications

As the most common bone disease, osteoporosis (OP) increases bone fragility and makes patients more vulnerable to the threat of osteoporotic fractures. With the ageing population in today's society, OP has become a huge and growing public health problem. Unfortunately, the clear pathogenesis of OP is still under exploration, and effective interventions are still scarce. Therefore, exploring new targets for pharmacological interventions to develop promising therapeutic drugs for OP is of great clinical value. Previous studies have shown that normal bone remodeling depends on proteostasis, whereas loss of proteostasis during ageing leads to the dysfunctional proteostasis network (PN) that fails to maintain bone homeostasis. Nevertheless, only a few studies have revealed the pathophysiological relationship between bone metabolism and a single component of PN, yet the role of PN as a whole in the pathogenesis of OP is still under investigation. This review comprehensively summarized the role of PN in the pathogenesis of OP and further discussed the potential of PN as innovative drug targets for the therapy of OP.

Focusing on Phosphorus Loads: From Healthy People to Chronic Kidney Disease

Phosphorus is an essential micromineral with a key role in cellular metabolism and tissue structure. Serum phosphorus is maintained in a homeostatic range by the intestines, bones, and kidneys. This process is coordinated by the endocrine system through the highly integrated actions of several hormones, including FGF23, PTH, Klotho, and 1,25D. The excretion kinetics of the kidney after diet phosphorus load or the serum phosphorus kinetics during hemodialysis support that there is a "pool" for temporary phosphorus storage, leading to the maintenance of stable serum phosphorus levels. Phosphorus overload refers to a state where the phosphorus load is higher than is physiologically necessary. It can be caused by a persistently high-phosphorus diet, renal function decline, bone disease, insufficient dialysis, and inappropriate medications, and includes but is not limited to hyperphosphatemia. Serum phosphorus is still the most commonly used indicator of phosphorus overload. Trending phosphorus levels to see if they are chronically elevated is recommended instead of a single test when judging phosphorus overload. Future studies are needed to validate the prognostic role of a new marker or markers of phosphorus overload.

METTL14 upregulates TCF1 through m6A mRNA methylation to stimulate osteogenic activity in osteoporosis

Alteration of N6-methyladenosine (m6A) is closely linked to spanning biological processes including osteoporosis (OP) development. This research focuses on the function of methyltransferase like 14 (METTL14) in bone turnover and its interaction with T cell factor 1 (TCF1). A mouse model of OP was established by ovariectomy (OVX). The bone mass parameters were evaluated by micro-CT analysis. Mouse MC3T3-E1 cells and mouse bone marrow macrophages (BMMs) were induced for osteogenic or osteoclastic differentiation, respectively, for in vitro experiments. The osteogenesis or osteoclasis activity was analyzed by measuring the biomarkers such as OPG, ALP, NFATC1, CTSK, RANKL, and TRAP. RT-qPCR and IHC assays identified reduced METTL14 expression in bone tissues of osteoporotic patients and ovariectomized mice. Artificial METTL14 overexpression increased bone mass of mice and promoted osteogenesis whereas suppressed osteoclasis both in vivo and in vitro. METTL14 promoted TCF1 expression through m6A mRNA methylation, and TCF1 increased the osteogenic activity by elevating the protein level of RUNX2, a key molecule linked to bone formation. In rescue experiments, TCF1 restored the RUNX2 level and osteogenic activity of cells suppressed by METTL14 silencing. In summary, this research demonstrates that METTL14 plays a protective role against OP by promoting the TCF1/RUNX2 axis.

Optimization of the Alizarin Red S Assay by Enhancing Mineralization of Osteoblasts

The alizarin red S assay is considered the gold standard for quantification of osteoblast mineralization and is thus widely used among scientists. However, there are several restrictions to this method, e.g., moderate sensitivity makes it difficult to uncover slight but significant effects of potentially clinically relevant substances. Therefore, an adaptation of the staining method is appropriate and might be obtained by increasing the mineralization ability of osteoblasts. In this study, cell culture experiments with human (SaOs-2) and murine (MC3T3-E1) osteoblasts were performed under the addition of increasing concentrations of calcium chloride (1, 2.5, 5, and 10 mM) or calcitonin (1, 2.5, 5, and 10 nM). After three or four weeks, the mineralization matrix was stained with alizarin red S and the concentration was quantified photometrically. Only calcium chloride was able to significantly increase mineralization, and therefore enhanced the sensitivity of the alizarin red S staining in a dose-dependent manner in both osteoblastic cell lines as well as independent of the cell culture well surface area. This cost- and time-efficient optimization enables a more sensitive analysis of potentially clinically relevant substances in future bone research.

Teff Grain-Based Functional Food for Prevention of Osteoporosis: Sensory Evaluation and Molecular Docking Approach

Osteoporosis is a highly prevalent skeletal disorder, which is characterized by compromised bone strength predisposing to an increased risk of fracture. The medical approaches presently followed for the prevention and treatment are associated with several side effects. Thus, it becomes important to design alternatives that are safer, economical, and easy to use. Plants provide us with a beneficial and effective option for such designs. They are rich in nutrients and phytochemicals that can be used to target signalling pathways to prevent the development of disease. For this purpose, we used Ethiopian grain, teff as a preventive strategy for osteoporosis as it has a favourable nutritional profile. In our study, we focussed on the preparation of functional multi-grain flour with Ethiopian grain, teff, and other ingredients that have a positive effect on bone health. A cookie was prepared from the multi mix flour and to analyze its shelf life and acceptance we performed a sensory evaluation where we observed no significant difference in the cookies' characteristics during the period of study. We also performed Molecular Docking of eight flavonoid polyphenols selected from the nutritional profile of the ingredients to understand their binding affinity, interaction with the target, receptor activator of nuclear factor kappa-Β ligand (RANKL), and prophylactic or therapeutic effects in the prevention of osteoporosis. It was found that all 8 flavonoid polyphenols bound with RANKL, at least at one of the crucial binding sites and so can be used for the prevention of osteoporosis.

Hyperoside suppresses osteoclasts differentiation and function through downregulating TRAF6/p38 MAPK signaling pathway

Hyperoside (HP), as a natural product, can promote proliferation and differentiation of osteoblasts and presents a protective effect on ovariectomized (OVX) mice. However, the inhibitory effect of HP on osteoclasts (OCs) and the potential mechanism remain to be elucidated. In this study, it was found that HP could effectively inhibit the differentiation and bone resorption of OCs, and its intrinsic molecular mechanism was related to the inhibition of TRAF6/p38 MAPK signaling pathway. Therefore, HP could be a promising natural compound for lytic bone diseases.

Morinda officinalis polysaccharide enable suppression of osteoclastic differentiation by exosomes derived from rat mesenchymal stem cells

CONTEXT

Morinda officinalis F.C. How. (MO) (Rubiaceae) can strengthen bone function.

OBJECTIVE

To examine the functional mechanism and effect of MO polysaccharides (MOPs) in rats with glucocorticoid-induced osteoporosis (GIOP).

MATERIALS AND METHODS

Rats with GIOP were treated with 5, 15 or 45 mL/kg of MOP [n = 15 for each dose, intraperitoneal (i.p.) injection every other day for 8 weeks]. The body weight of rats and histomorphology of bone tissues were examined. Bone marrow mesenchymal stem cells (BMSCs)-derived exosomes (Exo) were collected and identified. Bone marrow-derived macrophages (BMMs) were induced to differentiate into osteoclasts and treated with BMSC-Exo for in vitro studies.

RESULTS

MOP reduced the body weight (5, 15, or 45 mg/kg MOP vs. phosphate-buffered saline: 8%, 15% and 25%, p < 0.01), elevated the bone volume to tissue volume (BV/TV), mean trabecular thickness (Tb.Th), mean trabecular number (Tb.N) and mean connectivity density (Conn.D) (40-86%, p < 0.01), decreased the mean trabecular separation/spacing (Tb.Sp) (22-37%, p < 0.01), increased the cortical bone continuity (35-90%, p < 0.01) and elevated RUNX family transcription factor 2 and RANK levels (5-12%, p < 0.01), but suppressed matrix metallopeptidase 9 and cathepsin K levels (9-20%, p < 0.01) in femur tissues. BMSC-Exo from MOP-treated rats (MOP-Exo) suppressed osteoclastic differentiation and proliferation of BMMs. The downregulation of microRNA-101-3p (miR-101-3p) or the upregulation of prostaglandin-endoperoxide synthase 2 (PTGS2) blocked the functions of MOP-Exo.

DISCUSSION AND CONCLUSIONS

MOP inhibits osteoclastic differentiation and could potentially be used for osteoporosis management. This suppression may be enhanced by the upregulation of miR-101-3p or the inhibition of PTGS2.

Inhibitory Effects of Protopanaxadiol-Producing Transgenic Rice Seed Extracts on RANKL-Induced Osteoclast Differentiation

(1) Background: Osteoporosis is a disease in which bones are weakened and fractured easily because of various factors. It is mainly observed in elderly and postmenopausal women, and it continues to carry high economic costs in aging societies. Normal bone maintains a healthy state through a balanced process of osteoclast suppression and osteoblast activation; (2) Methods: In this study, osteoclast inhibition was induced by inhibiting osteoclast differentiation using ginseng protopanaxadiol-enriched rice (PPD-rice) seed extract. To analyze the effect of PPD-rice extract on the inhibition of osteoclast differentiation, bone marrow macrophages extracted from mice were treated with PPD-rice and Dongjin seed (non-transformed rice) extracts and analyzed for the inhibition of osteoclast differentiation; (3) Results: The results illustrated that PPD-rice extract reduced the transcription and translation of NFATc1, a modulator of osteoclast formation, decreased the mRNA expression of various osteoclast differentiation marker genes, and reduced osteoclast activity. Moreover, the bone resorptive activity of osteoclasts was diminished by PPD-rice extract on Osteo Assay plates; (4) Conclusions: Based on these results, PPD-rice extract is a useful candidate therapeutic agent for suppressing osteoclasts, an important component of osteoporosis, and it could be used as an ingredient in health supplements.

Finite-Element Analysis of the Effect of Utilizing Various Material Assemblies in “All on Four” on the Stresses on Mandible Bone and Prosthetic Parts

Background. Fixed prostheses often utilize the “All-on-four” technique, in which four implants are inserted into the jaw bone, and a framework supports them. Titanium is usually used in the fabrication of “All-on-four” parts, due to its superior mechanical properties; however, it has drawbacks such as aesthetic impairment, casting issues, stress shielding, and incompatibility with imaging techniques. These drawbacks have motivated researchers to find alternative materials such as polymers. Recently, the new polymeric material PEEK has a major role in most areas of dentistry, and therefore, it can represent an alternative biomaterial to overcome the drawbacks of titanium. The density of bone is expected to influence the choice of “All-on-four” materials. Purpose. This research applied finite-element investigations to evaluate the stresses on bone tissues and prosthetic parts in “All on four,” utilizing three assemblies of materials, in normal and low bone densities. These assemblies were titanium (Type 1), titanium/PEEK (Type 2), and PEEK (Type 3). Materials and Methods. A 3D Mandibular model was constructed with a fixed prosthesis, and three assemblies of materials were stimulated, under 300 N unilateral force. The von Mises stresses were computed for the prosthetic parts and mucosa, while the maximum and minimum principal stresses/strains were computed for bone tissues due to their brittle and ductile properties. Moreover, the displacements of implants were extracted to check the prosthesis stability. Results. Type 2 and Type 3 minimized the stresses on frameworks, implants, abutments, and bone tissues, however, increased the mucosal stress, in comparison to Type 1. In the low-density model, Type 3 was recommended to reduce the stresses/strains on bone tissues and decrease the implant displacement, avoiding bone failure and increasing prosthesis stability. Conclusions. The bone density influenced the choice of “All-on-four” assembly. Moreover, further research on PEEK implants and abutments is required in the future.

Estrogen Receptor 1 (ESR1) and the Wnt/β-Catenin Pathway Mediate the Effect of the Coumarin Derivative Umbelliferon on Bone Mineralization

Bone physiology is regulated by osteoblast and osteoclast activities, both involved in the bone remodeling process, through deposition and resorption mechanisms, respectively. The imbalance between these two phenomena contributes to the onset of bone diseases. Among these, osteoporosis is the most common metabolic bone disorder. The therapies currently used for its treatment include antiresorptive and anabolic agents associated with side effects. Therefore, alternative therapeutic approaches, including natural molecules such as coumarin and their derivatives, have recently shown positive results. Thus, our proposal was to investigate the effect of the coumarin derivative umbelliferon (UF) using an interesting model of human osteoblasts (hOBs) isolated from osteoporotic patients. UF significantly improved the activity of osteoporotic-patient-derived hOBs via estrogen receptor 1 (ESR1) and the downstream activation of β-catenin pathway. Additionally, hOBs were co-cultured in microgravity with human osteoclasts (hOCs) using a 3D system bioreactor, able to reproduce the bone remodeling unit in bone loss conditions in vitro. Notably, UF exerted its anabolic role by reducing the multinucleated cells. Overall, our study confirms the potential efficacy of UF in bone health, and identified, for the first time, a prospective alternative natural compound useful to prevent/treat bone loss diseases such as osteoporosis.

Effect of physical therapy on bone remodelling in preterm infants: a multicenter randomized controlled clinical trial

Background

Preterm infants have a low level of bone mineralization compared to those born at term, since 80% of calcium incorporation occurs at the end of pregnancy. The purpose of the present study was to investigate the effect of reflex locomotion therapy on bone modeling and growth in preterm infants and to compare its effect with those of other Physiotherapy modalities.

Methods

A multicentre randomized controlled clinical trial was conducted (02/2016 – 07/2020). 106 preterm infants born at the Virgen de la Arrixaca University Clinical Hospital, the General University Hospital of Elche and the Torrecárdenas University Hospital of Almería, between 26 and 34 weeks with hemodynamic stability, complete enteral nutrition and without any metabolic, congenital, genetic, neurological or respiratory disorders were evaluated for inclusion. Infants were randomly assigned to three groups: one group received reflex locomotion therapy (EGrlt); another group received passive mobilizations with gentle joint compression (EGpmc); and the control group received massage (CG). All treatments were carried out in the neonatal units lasting one month. The main outcome measure was bone formation and resorption measured with bone biomarkers. A mixed ANOVA was used to compare the results of bone biomarkers, and anthropometric measurements.

Results

Infants were randomized to EGrlt (n = 38), EGpmc (n = 32), and CG (n = 36). All groups were similar in terms of gender (p = 0.891 female 47.2%), gestational age (M = 30.753, SD = 1.878, p = 0.39) and birth weight (M = 1413.45, SD = 347.36, p = 0.157). At the end of the study, significant differences were found between the groups in their interaction in bone formation, measured with osteocalcin [F (2,35) = 4.92, p = 0.013, η_p² = 0.043], in benefit of the EGrlt.

Conclusions

Reflex locomotion therapy has been effective in improving bone formation, more so than other Physiotherapy modalities. Therefore, reflex locomotion therapy could be considered one of the most effective physiotherapeutic modalities for the prevention and treatment of osteopenia of prematurity.

Trial registrstion

Trial retrospectively registered at ClinicalTrials.gov. First posted on 22/04/2020. Registration number: NCT04356807.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03402-2.

Anti-osteoporosis effects and regulatory mechanism of Lindera aggregata based on network pharmacology and experimental validation

Osteoporosis (OP) is characterized by the flaccidity of bones or bone bi-disease caused by kidney deficiency. Lindera aggregate has been used to strengthen kidney function in China for thousands of years. It has been approved by Chinese Pharmacopoeia that the root of Lindera aggregata (RLA) can replenish and tonify the kidney, which is thought to be an effective way to alleviate OP. In this study, a network pharmacology approach was applied to explore the active components and potential mechanisms of RLA in osteoporosis treatment. Then, the ethanolic extract of the root of L. aggregata (EERL) was prepared and these predicted results were validated by prednisone-induced zebrafish embryos model. Moreover, the candidate compounds were identified by UPLC-ESI-MS/MS. The anti-OP results showed that EERL could significantly reverse the bone loss of zebrafish induced by prednisone. The mRNA expressions results showed that EERL decreased osteoclast bone resorption by regulating the RANK/RANKL/OPG system. Also, it increased bone formation by regulating the gene expressions of spp1, mmp2, mmp9, runx2b, alp, and entpd5a. Our results demonstrated the reliability of the network pharmacology method, and also revealed the anti-OP effect and potential mechanism of RLA.

Acid Neutralization and Immune Regulation by Calcium-Aluminum-Layered Double Hydroxide for Osteoporosis Reversion

Osteoporosis is a kind of global chronic bone disease characterized by progressive loss of bone mass and bone quality reduction, leading to a largely increased risk of bone fragility. In clinics, the current treatment of osteoporosis relies on the inhibition of bone damage by osteoclasts but ignores the function of immune cells in the progress of osteoporosis, leading to much compromised therapeutic efficacy. In this work, a highly effective osteoporosis-immunotherapeutic modality is established for the treatment of osteoporosis based on acid neutralization in synergy with immune microenvironment regulation by a specially designed nanocatalytic medicine, calcein functionalized calcium-aluminum-layered double hydroxide (CALC) nanosheets. Briefly, the mildly alkaline CALC nanosheets could neutralize the acidic microenvironment of osteoporosis accompanying the acidity-responsive LDH degradation. Subsequently, calcium phosphate nanoparticles (CAPs) are generated by the reaction between the released Ca²⁺ from LDH degradation and endogenous phosphates, resulting in M2 phenotype anti-inflammatory differentiation of bone macrophages through a c-Maf transcriptional factor pathway and the following activity enhancements of regulatory T cells (T_reg) and the deactivation of T helper 17 cells (T_H17). Both in vitro and in vivo results show an excellent therapeutic efficacy on osteoporosis featuring a significant BV/TV (%) enhancement of femurs from 6.2 to 10.7, demonstrating high feasibility of this therapeutic concept through the combined acid neutralization and immune regulation. Such an inorganic nanomaterial-based strategy provides a novel, efficient, and biosafe therapeutic modality for intractable osteoporosis treatment, which will benefit patients suffering from osteoporosis.

Finite Element Analysis of Cannulated Screws as Prophylactic Intervention of Hip Fractures

Introduction

The frequency of hip fractures, a major cause of morbidity and mortality for geriatric patients, is expected to increase exponentially in the next few decades. The aim of this study is to assess the ability of stainless-steel cannulated screws to reduce the risk of a femoral neck fracture, if placed prophylactically prior to a fall.

Materials and Methods

We created finite element models from computed tomography (CT) scan-based 3D models of a geriatric patient through 3D-image processing and model generation software. We used linear finite element simulations to analyze the effect of cannulated screws in the proximal femur in single-leg stance and lateral fall, which were processed for peak von Mises stresses and element failure.

Findings

Prophylactically placed cannulated screws significantly reduced failure in an osteoporotic proximal femur undergoing lateral fall. Three implanted screws in an inverted triangle formation decreased proximal femoral trabecular failure by 21% and cortical failure by 5%. This reduction in failure was achieved with a 55% decrease in femoral neck failure and 14% in lateral cortex failure.

Conclusion

Our results indicate that cannulated hip screws in an inverted triangle formation may strengthen an osteoporotic proximal femur in the event of a lateral fall. Mechanical testing on cadaveric or composite models is required to validate these results.

Sleep pattern and bone mineral density: a cross-sectional study of National Health and Nutrition Examination Survey (NHANES) 2017-2018

This research is a cross-sectional study based on the participants aged 50 years and older from National Health and Nutrition Examination Survey (NHANES) database. Poor sleep patterns were associated with lower bone mineral density (BMD) and a higher risk of osteoporosis, especially among older individuals or females.

INTRODUCTION

Accumulated evidence demonstrates that sleep duration, which is one aspect of sleep pattern, is associated with the risk of osteoporosis. However, the related studies on the association between sleep patterns and the risk of osteoporosis were limited. Therefore, this research aims to investigate the association of sleep patterns with BMD and the risk of osteoporosis among individuals aged 50 years and older.

METHODS

Participants aged ≥ 50 years from the NHANES database were included in the present study. The diagnosis of osteoporosis was based on the results of BMD testing. Moreover, all the participants were divided into different sleep pattern groups according to nocturnal sleep duration and bedtime. In addition, this study used multivariate linear regression models to evaluate the association between sleep patterns and BMD and exploited multiple logistic regression models to investigate the odds ratios (ORs) for osteoporosis.

RESULTS

Finally, 1,865 individuals (non-osteoporosis: N = 1,713; osteoporosis: N = 152) aged over 50 years old with complete data were analyzed. The results of multivariate linear regression models showed that individuals with normal sleep duration/later bedtime or long sleep duration/later bedtime had lower femoral BMD than those with normal sleep duration/usual bedtime. Moreover, subjects with long sleep duration/later bedtime had a higher risk of osteoporosis compared with those with normal sleep duration/usual bedtime. In addition, subgroup analyses revealed the association of sleep patterns with BMD and the risk of osteoporosis appeared to be more pronounced among individuals aged ≥ 65 years or females.

CONCLUSION

This study demonstrated that sleep patterns are associated with BMD and the risk of osteoporosis. Poor sleep patterns contribute to decreased bone mass and the increased risk of osteoporosis. Therefore, a healthy sleep pattern is favorable for the prevention of osteoporosis.

Naringin promotes osteogenesis and ameliorates osteoporosis development by targeting JAK2/STAT3 signalling

Osteoporosis is a systemic bone metabolism disorder, which increases the risk of fractures, and in severe cases it may cause disability or even death. An important factor contributing to osteoporosis is the imbalance between bone formation and resorption. Naringin was reported to promote osteoblast differentiation, thus enhancing bone formation and alleviating osteoporosis development. However, the signalling pathways related to the regulatory mechanism of naringin in osteoporosis development are not clear. Proliferation of bone mesenchymal stem cells (BMSCs) treated with naringin in vitro was detected by CCK-8. An osteogenesis differentiation medium supplemented with naringin was applied to explore the effects of naringin on BMSC osteogenic differentiation, as detected by Alizarin red staining. Ovariectomy (OVX)-induced postmenopausal osteoporosis (PMOP) rats were orally administered with naringin. Dual-energy X-ray absorptiometry (DEXA) and micro-CT were applied to measure bone mineral density (BMD), bone volume/total volume (BV/TV), trabecula thickness (Tb.Th), trabecula number (Tb.N), trabecular separation (Tb.Sp) and bone surface/bone volume (BS/BV). H&E staining was performed to show pathological changes of the femur in PMOP rats after naringin treatment. Bone metabolism indicators were assessed by ELISA. We found that naringin suppressed the activation of the JAK2/STAT3 pathway. Naringin promoted BMSC proliferation and osteogenic differentiation. Furthermore, naringin alleviates bone loss and improves abnormal bone metabolism of PMOP rats. Collectively, naringin promotes BMSC osteogenic differentiation to ameliorate osteoporosis development by targeting JAK2/STAT3 signalling.

miR-330-5p in Small Extracellular Vesicles Derived From Plastrum testudinis-Preconditioned Bone Mesenchymal Stem Cells Attenuates Osteogenesis by Modulating Wnt/β-Catenin Signaling

The bone microenvironment is crucial for the growth and development of different types of osteocytes. Small extracellular vesicles (sEVs) secreted by bone mesenchymal stem cells are delivered to target cells where their contents regulate biological functions. Here, we evaluated the osteogenic effects and mechanism of sEVs derived from Plastrum testudinis-preconditioned bone mesenchymal stem cells (PT-sEV). The osteogenic effects of PT-sEV were evaluated by the differentiation of osteoblasts and the alternation of bone quality and quantity in ovariectomized rats. The specific mechanism was explored by high-throughput sequencing and verified by transfection with the corresponding miRNA mimic and inhibitor. RNA-sequence identified a unique enrichment of a set of miRNAs in PT-sEV compared with sEVs derived from untreated BMSCs. Overexpression or inhibition in vitro indicated that the osteogenic inducing potential of sEVs was mainly attributable to miR-330-5p, one of the most dramatically downregulated miRNAs in the PT-sEV fraction. Dual luciferase reporter assays showed that miR-330-5p negatively regulated osteogenesis by directly binding to the 3′ untranslated region of Tnc. Additional experiments showed that Tnc regulated Wnt/β-catenin signaling, and rescue experiment showed that miR-330-5p could restore β-catenin expression; additionally, animal experiments indicated that Wnt signaling was inactivated in the ovariectomized rats. These data demonstrated the regenerative potential of PT-sEV, which induced osteogenic differentiation of pre-osteoblasts, leading to bone formation. This process was achieved by delivering miR-330-5p, which regulated Tnc to control Wnt/β-catenin signaling.

M1 macrophage-derived exosomes aggravate bone loss in postmenopausal osteoporosis via a microRNA-98/DUSP1/JNK axis

Macrophages (Mφs) are master regulators of the immune response and may serve as therapeutic targets in aging societies. This study aimed to determine the function of M1Mφ-exosomes (Exos) in the development of osteoporosis (OP) and the involvement of microRNA (miR)-98 and dual specificity phosphatase 1 (DUSP1). A murine model of OP was established using ovariectomies (OVX). Bone loss was observed in OVX-treated mice, as manifested by reduced bone mineral density and decreased number of bone trabecula. The bone loss was further aggravated by treatment with M1Mφ-Exos. Exos also suppressed osteogenic differentiation of MC3T3-E1 cells. miRNA microarray analysis revealed that the miR-98 level was notably upregulated in cells after Exo treatment, and DUSP1 was confirmed as a target of miR-98. Meanwhile, downregulation of miR-98 or upregulation of DUSP1 restored the osteogenic differentiation ability of MC3T3-E1 cells. In addition, upregulation of DUSP1 reduced bone loss in murine bone tissues and suppressed JNK phosphorylation. In summary, M1Mφ-derived exosomal miR-98 exacerbates bone loss and OP by downregulating DUSP1 and activating the JNK signaling pathway. miR-98 may therefore serve as a therapeutic target in OP management.

Pelvic Organ Prolapse Is Associated with Osteoporosis in Korean Women: Analysis of the Health Insurance Review and Assessment Service National Patient Sample

Background and Objectives: Pelvic organ prolapse (POP) and osteoporosis are major disease entities in older women that have the same epidemiology and might also have the same molecular physiology. However, few data have been reported on the relationship between POP and osteoporosis. We designed this study to examine the association between POP and osteoporosis in Korean women. Materials and Methods: We used the Health Insurance Review and Assessment Service 2015 to 2017 National Patient Sample (HIRA-NPS). A total of 4,368,141 individuals were included in this study, and a total of 842,228 individuals aged 50 years and above were included in the final analysis. POP patients were defined by the Korean Informative Classification of Diseases (KOICD) codes (KCD-7, N81, or N99.3) and patients who underwent a pelvic reconstructive procedure. The osteoporosis patients were defined by KOICD (KCD-7, R4113, R3620, R0402,) who were prescribed osteoporosis medication. A 1:10 age-stratified matching and chi-squared test were used for statistical analysis, and p < 0.05 was considered as significant. Results: A total of 7359 women were included in this analysis. Advanced POP was correlated with osteoporosis in Korean women aged 50 years and above in 2015–2017 (p < 0.0001). After adjusting for age, advanced POP was correlated with osteoporosis in the 2015, 2016, and 2017 dataset (p = 0.013, 0.0009, 0.0119, respectively). Conclusions: Advanced POP is correlated with osteoporosis in Korean women aged 50 years and above. Evaluation for osteoporosis and education about bone health can be especially important, even in relatively young women, aged 50–59 years, and POP patients.

PINK1/Parkin-Mediated Mitophagy Plays a Protective Role in the Bone Impairment Caused by Aluminum Exposure

The pollution of aluminum (Al) in agricultural production and its wide application in food processing greatly increase the chance of human and animal exposure. Al can accumulate in bone and cause bone diseases by inducing oxidative stress. Mitophagy can maintain normal cell function by degrading damaged mitochondria and scavenging reactive oxygen species. However, the role of mitophagy in the bone impairment caused by Al is unknown. In this study, we demonstrated that PTEN induced putative kinase 1 (PINK1)/ E3 ubiquitin ligase PARK2 (Parkin)-mediated mitophagy was activated in the bone impairment caused by Al in vivo. Then, the Al-induced mitophagy in Parkin-deficient mice and MC3T3-E1 cells were decreased. Meanwhile, Parkin deficiency exacerbated the bone impairment, mitochondrial damage, and oxidative stress under Al exposure, both in vivo and in vitro. In general, the results reveal that Al exposure can activate PINK1/Parkin-mediated mitophagy, and the PINK1/Parkin-mediated mitophagy plays a protective role in the bone impairment caused by Al.

Circ-ITCH sponges miR-214 to promote the osteogenic differentiation in osteoporosis via upregulating YAP1

Osteoporosis is the most prevailing primary bone disease and a growing health care burden. The aim of this study was to clarify the functional roles and mechanisms of the circ-ITCH regulating osteogenic differentiation of osteoporosis. Circ-ITCH and yes-associated protein 1 (YAP1) levels were downregulated, but the miR‐214 level was upregulated in osteoporotic mice and patients. Knockdown of circ-ITCH inhibited the alkaline phosphatase (ALP) activity, mineralized nodule formation, and expression of runt-related transcription factor 2 (RUNX2), osteopontin (OPN), and osteocalcin (OCN) during osteogenic induction. Furthermore, miR-214 was a target of circ-ITCH, knockdown of miR-214 could impede the regulatory effects of sh-circ-ITCH on osteogenic differentiation. Moreover, miR-214 suppressed hBMSCs osteogenic differentiation by downregulating YAP1. Finally, in vivo experiments indicated that overexpression of circ-ITCH could improve osteogenesis in ovariectomized mice. In conclusion, circ-ITCH upregulated YAP1 expression to promote osteogenic differentiation in osteoporosis via sponging miR-214. Circ-ITCH could act as a novel therapeutic target for osteoporosis.

ETS Proto-Oncogene 1 Suppresses MicroRNA-128 Transcription to Promote Osteogenic Differentiation Through the HOXA13/β-Catenin Axis

ETS proto-oncogene 1 (ETS1) has been implicated in osteoporosis (OP), but the exact molecular mechanisms are complex. This work focuses on the impact of ETS1 on the osteogenic differentiation and the molecules involved. A mouse pre-osteoblast cell line MC3T3-E1 was used for in vitro experiments. ETS1 was upregulated during the process of osteogenic differentiation of MC3T3-E1 cells. Overexpression of ETS1 promoted expression of osteogenic markers, alkaline phosphate concentration, and calcareous accumulation in cells. ETS1 was found to specifically bind to miR-128 promoter to suppress its transcription, while miR-128 could target homeobox A13 (HOXA13). Therefore, ETS1 suppressed miR-128 transcription to upregulate HOXA13 expression. Overexpression of HOXA13 promoted the osteogenic differentiation ability of cells and increased the protein level of β-catenin. Either overexpression of miR-128 or downregulation of β-catenin by CWP232228, a β-catenin-specific antagonist, blocked the promoting roles of ETS1 in cells. To conclude, this study provided evidence that ETS1 suppresses miR-128 transcription to activate the following HOXA13/β-catenin axis, therefore promoting osteogenic differentiation ability of MC3T3-E1 cells. This finding may offer novel ideas for OP treatment.

Trelagliptin stimulates osteoblastic differentiation by increasing runt-related transcription factor 2 (RUNX2): a therapeutic implication in osteoporosis

Osteoporosis, an aging-associated bone metabolic disease, is affecting millions of people worldwide. The deregulated process of osteoblastic differentiation has been linked with the progression of osteoporosis. Trelagliptin is a long-acting inhibitor of DPP-4 used for the management of type 2 diabetes mellitus. However, it is unknown whether Trelagliptin possesses a beneficial effect in osteoblastic differentiation. Interestingly, we found that treatment with Trelagliptin enhanced differentiation and promoted the mineralization of MC3T3-E1 cells. Firstly, Trelagliptin increased the activity of alkaline phosphatase (ALP) and promoted osteoblastic calcium deposition. Additionally, treatment with Trelagliptin upregulated ALP, osteocalcin (OCN), osteopontin (OPN), and bone morphogenetic protein-2 (BMP-2). Notably, Trelagliptin increased RUNX2, a major regulator of osteoblastic differentiation. Mechanistically, Trelagliptin upregulated the levels of p-AMPKα. Blockage of AMPK with compound C abolished the effects of Trelagliptin in RUNX2 and osteoblastic differentiation, suggesting the involvement of AMPK. Our findings suggest that Trelagliptin might possess a potential for the treatment of osteoporosis.

Aqueous Extract of Salvia miltiorrhiza Bunge-Radix Puerariae Herb Pair Attenuates Osteoporosis in Ovariectomized Rats Through Suppressing Osteoclast Differentiation

Traditional herb pair Salvia miltiorrhiza Bunge-Radix Puerariae (DG) owns various biological activities including anti-inflammatory and anti-oxidative stress. Oxidative stress is one high-risk factor for osteoporosis, then effect of DG on osteoporosis and underlying mechanisms was explored both in vivo and in vitro. Firstly, the predication from network pharmacology hinted that DG has the potential for ameliorating osteoporosis. Consistent with predication, DG significantly restored bone loss and deficiency of type II collagen, decreased TRAP and Cathepsin K positive areas in femur. Meanwhile it improved important characteristics of microarchitectural deterioration of tissue, reduced the numbers of NFATc1-positive osteoclast in the vertebra as well as decreased the serum osteoclast-specific cytokine RANKL and OPG release in OVX rats exhibiting its protective effect against osteoporosis. In vitro, DG noticeably decreased osteoclastic-special marker protein expressions of RANK, c-Fos and NFATc1. Furthermore, autophagy pathway p62/LC3B, ROS production and NF-κB were all activated by RANKL stimulation and blocked by DG pretreatment. Moreover, autophagy inhibitors, ROS scavenger, Ca²⁺ chelator and NF-κB inhibitor remarkably suppressed c-Fos and NFATc1 expressions. Taken together, DG may ameliorate osteoporosis by regulating osteoclast differentiation mediated by autophagy and oxidative stress. This study provided a mechanistic basis for DG treating osteoporosis and offered a safe dose for DG in preventing and improving bone diseases.

Combined therapy of adipose-derived stem cells and photobiomodulation on accelerated bone healing of a critical size defect in an osteoporotic rat model

We investigated the impact of human demineralized bone matrix (hDBM) plus adipose-derived stem cells (hADS) plus photobiomodulation (PBM) on a critical-sized femoral defect (CSFD) in ovariectomy induced osteoporosis in rats. There were 6 groups as follows. In group 1 (control, C), only CSFDs were created. Groups 2-6 were implanted with DBM into the CSFD (DBM-CSFD). In group 2 (S), only DBM was transplanted into the CSFD. In group 3 (S + PBM), the DBM-CSFDs were treated with PBM. In group 4, the DBM-CSFDs were treated with alendronate (S + ALN). In group 5, ADSs were seeded into DBM-CSFD (S + ADS). In group 6, ADSs were seeded into DBM-CSFD and the CSFDs were treated with PBM (S + PBM + ADS). At week eight (catabolic phase of bone repair), the S + ALN, S + PBM + ADS, S + PBM, and S + ADS groups all had significantly increased bone strength than the S group (ANOVA, p = 0.000). The S + PBM, S + PBM + ADS, and S + ADS groups had significantly increased Hounsfield unit than the S group (ANOVA, p = 0.000). ALN, ADS, and PBM significantly increased healed bone strength in an experimental model of DBM-treated CSFD in the catabolic phase of bone healing in osteoporotic rats. However, ALN alone and PBM plus ADS were superior to the other protocols.

Bisphosphonates and parathyroid hormone analogs for improving bone quality in spinal fusion: State of evidence

Spinal fusion is among the most commonly performed surgical procedures for elderly patients with spinal disorders - including degenerative disc disease with spondylolisthesis, deformities, and trauma. With the large increase in the aging population and the prevalence of osteoporosis, the number of elderly osteoporotic patients needing spinal fusion has risen dramatically. Due to reduced bone quality, postoperative complications such as implant failures, fractures, post-junctional kyphosis, and pseudarthrosis are more commonly seen after spinal fusion in osteoporotic patients. Therefore, pharmacologic treatment strategies to improve bone quality are commonly pursued in osteoporotic cases before conducting spinal fusions. The two most commonly used pharmacotherapeutics are bisphosphonates and parathyroid hormone (PTH) analogs. Evidence indicates that using bisphosphonates and PTH analogs, alone or in combination, in osteoporotic patients undergoing spinal fusion, decreases complication rates and improves clinical outcomes. Further studies are needed to develop guidelines for the administration of bisphosphonates and PTH analogs in osteoporotic spinal fusion patients in terms of treatment duration, potential benefits of sequential use, and the selection of either therapeutic agents based on patient characteristics.

Synthesis and biological activities of drugs for the treatment of osteoporosis

Osteoporosis is an asymptomatic progressive disease. With the improvement of people's living standard and the aging of population, osteoporosis and its fracture have become one of the main diseases threatening the aging society. The serious medical and social burden caused by this has aroused wide public concern. Osteoporosis is listed as one of the three major diseases of the elderly. At present, the drugs for osteoporosis include bone resorption inhibitors and bone formation promoters. The purpose of these anti-osteoporosis drugs is to balance osteoblast bone formation and osteoclast bone resorption. With the development of anti-osteoporosis drugs, new anti osteoporosis drugs have been designed and synthesized. There are many kinds of new compounds with anti osteoporosis activity, but most of them are concentrated on the original drugs with anti osteoporosis activity, or the natural products with anti-osteoporosis activity are extracted from the natural products for structural modification to obtain the corresponding derivatives or analogues. These target compounds showed good ALP activity in vitro and in vivo, promoted osteoblast differentiation and mineralization, or had anti TRAP activity, inhibited osteoclast absorption. This work attempts to systematically review the studies on the synthesis and bioactivity of anti-osteoporosis drugs in the past 10 years. The structure-activity relationship was discussed, which provided a reasonable idea for the design and development of new anti-osteoporosis drugs.