Osteoporosis Model Research Articles

Estrogen-regulated miRs in bone enhance osteoblast differentiation and matrix mineralization

Estrogen signaling is critical for the development and maintenance of healthy bone, and age-related decline in estrogen levels contributes to the development of post-menopausal osteoporosis. Most bones consist of a dense cortical shell and an internalmesh-like network of trabecular bone that respond differently to internal and external cues such as hormonal signaling. To date, no study has assessed the transcriptomic differences that occur specifically in cortical and trabecular bone compartments in response to hormonal changes. To investigate this, we employed a mouse model of post-menopausal osteoporosis (ovariectomy, OVX) and estrogen replacement therapy (ERT). mRNA and miR sequencing revealed distinct transcriptomic profiles between cortical and trabecular bone in the setting of OVX and ERT. Seven miRs were identified as likely contributors to the observed estrogen-mediated mRNA expression changes. Of these, four miRs were prioritized for further study and decreased predicted target gene expression in bone cells, enhanced the expression of osteoblast differentiation markers, and altered the mineralization capacity of primary osteoblasts. As such, candidate miRs and miR mimics may have therapeutic relevance for bone loss resulting from estrogen depletion without the unwanted side effects of hormone replacement therapy and therefore represent novel therapeutic approaches to combat diseases of bone loss.

Effects of Piper sarmentosum on Bone Health and Fracture Healing: A Scoping Review.

Piper sarmentosum (PS) is a traditional herb used by Southeast Asian communities to treat various illnesses. Recent pharmacological studies have discovered that PS possesses antioxidant and anti-inflammatory activities. Since oxidative stress and inflammation are two important processes driving the pathogenesis of bone loss, PS may have potential therapeutic effects against osteoporosis. This review systematically summarised the therapeutic effects of PS on preventing osteoporosis and promoting fracture healing. A systematic literature search was performed in November 2021 using 4 electronic databases and the search string "Piper sarmentosum" AND (bone OR osteoporosis OR osteoblasts OR osteoclasts OR osteocytes). Nine unique articles were identified from the literature. The efficacy of PS has been studied in animal models of osteoporosis induced by ovariectomy and glucocorticoids, as well as bone fracture models. PS prevented deterioration of bone histomorphometric indices, improved fracture healing and restored the biomechanical properties of healed bone in ovariectomised rats. PS also prevented osteoblast/osteocyte apoptosis, increased bone formation and mineralisation and subsequently improved trabecular bone microstructures and strength of rats with osteoporosis induced by glucocorticoids. Apart from its antioxidant and anti-inflammatory activity, PS also suppressed circulating and skeletal expression of corticosterone and skeletal expression of 11β hydroxysteroid dehydrogenase type 1 but increased the enzyme activity in the glucocorticoid osteoporosis model. This review also identified several research gaps about the skeletal effects of PS and suggested future studies to bridge these gaps. PS may be of therapeutic benefit to bone health. However, further research is required to validate this claim.

Active components and mechanism of Jinwugutong Capsules in treatment of osteoporosis: a study based on UPLC-Q-Exactive-MS/MS combined with network pharmacology

UPLC-Q-Exactive-MS/MS and network pharmacology were employed to preliminarily study the active components and mechanism of Jinwugutong Capsules in the treatment of osteoporosis. Firstly, UPLC-Q-Exactive-MS/MS was employed to characterize the chemical components of Jinwugutong Capsules, and network pharmacology was employed to establish the "drug-component-target-pathway-disease" network. The key targets and main active components were thus obtained. Secondly, AutoDock was used for the molecular docking between the main active components and key targets. Finally, the animal model of osteoporosis was established, and the effect of Jinwugutong Capsules on the expression of key targets including RAC-alpha serine/threonine-protein kinase(AKT1), albumin(ALB), and tumor necrosis factor-alpha(TNF-α) was determined by enzyme-linked immunosorbent assay(ELISA). A total of 59 chemical components were identified from Jinwugutong Capsules, among which coryfolin, 8-prenylnaringenin, demethoxycurcumin, isobavachin, and genistein may be the main active components of Jinwugutong Capsules in treating osteoporosis. The topological analysis of the protein-protein interaction(PPI) network revealed 10 core targets such as AKT1, ALB, catenin beta 1(CTNNB1), TNF, and epidermal growth factor receptor(EGFR). The Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment showed that Jinwugutong Capsules mainly exerted the therapeutic effect by regulating the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT) signaling pathway, neuroactive ligand-receptor interaction, mitogen-activated protein kinase(MAPK) signaling pathway, Rap1 signaling pathway and so on. Molecular docking showed that the main active components of Jinwugutong Capsules well bound to the key targets. ELISA results showed that Jinwugutong Capsules down-regulated the protein levels of AKT1 and TNF-α and up-regulated the protein level of ALB, which preliminarily verified the reliability of network pharmacology. This study indicates that Jinwugutong Capsules may play a role in the treatment of osteoporosis through multiple components, targets, and pathways, which can provide reference for the further research.

Osteoclast-targeted delivery of anti-miRNA oligonucleotides by red blood cell extracellular vesicles.

Osteoporosis (OP) affects millions worldwide but currently cannot be cured. Suppressing the level of miR-214 in osteoclasts by the anti-miRNA oligonucleotide (AMO) anti-miR-214 reverses bone absorption and provides a potential treatment. Here we report a peptide-guided delivery strategy using red blood cell extracellular vesicles (RBCEVs) as the vehicle to realize osteoclast-targeted delivery of anti-miR-214. A bi-functional peptide, TBP-CP05, which binds to both the CD63 on RBCEVs and receptors on osteoclasts, acts as the guide. TBP-CP05 binds with RBCEVs through CP05, displays the TRAP-binding peptide (TBP) on the surface of EVs, and endows RBCEVs with osteoclast-targeting capability both in vitro and in vivo. Intravenous injection of the osteoclast-targeting RBCEVs (OT-RBCEVs) led to the enrichment of EVs in the bone skeleton, significant inhibition of the osteoclast activity, elevated osteoblast activity, and improved bone density in osteoporotic mice. Altogether, this work demonstrates efficient guidance of drug-loaded EVs to the targeted cells in vivo using bi-functional fusion peptides, and showcases that targeted delivery of anti-miR-214 by OT-RBCEVs may be a viable method for OP treatment. SIGNIFICANCE STATEMENT. Surface functionalization of EVs endows these nanovesicles cell-specific targeting property which guides the drug cargos to specific tissues and cells with higher accuracy, longer retention, and minimal off-target effects. Methods to functionalize EVs with minimal procedures are highly desired for clinical applications. Here we present a facile method using a bifunctional fusion peptide to guide RBCEVs to osteoclasts. A simple incubation of the bifunctional peptide and RBCEVs results in osteoclast-targeting RBCEVs (OT-RBCEVs) that effectively deliver anti-miR-214 to osteoclasts in vivo in a mouse model of osteoporosis, bringing a potential therapy to osteoporotic patients. This is, to our knowledge, the first report on peptide functionalization of RBCEVs and osteoclast-targeted delivery using RBCEVs.

Development of Machine Learning Models for Predicting Osteoporosis in Patients with Type 2 Diabetes Mellitus-A Preliminary Study.

Diagnosing osteoporosis in T2DM based on bone mineral density (BMD) remains challenging. We sought to develop prediction models employing machine learning algorithms for use as screening instruments for osteoporosis in T2DM patients. Data were collected from 433 participants and analyzed using nine categorical machine learning algorithms to select features based on demographic and clinical variables. Multiple classification models were compared using the area under the receiver operating characteristic curve (ROC-AUC), accuracy, sensitivity, specificity, the average precision (AP), precision, F1 score, precision-recall curves, calibration plots, and decision curve analysis (DCA) to determine the best model. In addition, 5-fold cross-validation was utilized to optimize the model, followed by an evaluation of feature significance using Shapley Additive exPlanations (SHAP). Using latent class analysis (LCA), distinct subpopulations were identified by constructing several discrete clusters. In this study, nine feature variables were identified to construct predictive models for osteoporosis in individuals with T2DM. The machine learning algorithms achieved an AP range of 0.444-1.000. The XGBoost model was selected as the final prediction model with an AUROC of 0.940 in the training set, 0.772 in the validation set for 5-fold cross-validation, and 0.872 in the test set. Using SHAP methodology, 25(OH)D was identified as the most important risk factor. Additionally, a 3-Class model was constructed using LCA, which categorized individuals into high, medium, and low-risk groups. Our study developed a predictive model with high accuracy and clinical validity for predicting osteoporosis in type 2 diabetes patients. We also identified three subpopulations with varying osteoporosis risk using clustering. However, limited sample size warrants cautious interpretation of results, and validation in larger cohorts is needed.

Robo2 promotes osteoblast differentiation and mineralization through autophagy and is activated by parathyroid hormone induction.

As a systemic skeletal disorder, osteoporosis can increase fracture risk. This study wants to discuss the mechanism of osteoporosis and find possible molecular therapy. Bone morphogenetic protein 2 (BMP2) was utilized to stimulate MC3T3-E1 to establish a cellular osteoporosis model in vitro. Initially, the viability of BMP2-induced MC3T3-E1 was assessed with a Cell counting kit-8 (CCK-8) assay. By real-time quantitative PCR (RT-qPCR) and western blot, Robo2 expression after roundabout (Robo) silencing or overexpression was estimated. Besides, alkaline phosphatase (ALP) expression, mineralization level and LC3II green fluorescent protein (GFP) expression were evaluated using ALP assay, Alizarin red staining and immunofluorescence staining, separately. Additionally, the expression of proteins related to osteoblast differentiation and autophagy was analyzed by RT-qPCR and western blot. Then, following autophagy inhibitor 3-methyladenine (3-MA) treatment, osteoblast differentiation and mineralization were measured again. MC3T3-E1 cells were differentiated into osteoblasts under BMP2 induction and Robo2 expression was greatly ascended. After Robo2 silencing, Robo2 expression was markedly diminished. ALP activity and mineralization level in BMP2-induced MC3T3-E1 cells were declined after depleting Robo2. Robo2 expression was conspicuously enhanced after overexpressing Robo2. Robo2 overexpression promoted the differentiation and mineralization of BMP2-induced MC3T3-E1 cells. Rescue experiments revealed that Robo2 silence and its overexpression could regulate the autophagy of BMP2-stimulated MC3T3-E1 cells. After 3-MA treatment, the increased ALP activity and mineralization level of BMP2-induced MC3T3-E1 cells with Robo2 upregulation were reduced. Furthermore, parathyroid hormone 1-34 (PTH1-34) treatment enhanced the expression of ALP, Robo2, LC3II and Beclin-1 and reduced the levels of LC3I and p62 of MC3T3-E1 cells concentration-dependently. Collectively, Robo2, which was activated by PTH1-34, promoted osteoblast differentiation and mineralization through autophagy.

Development and Validation of a New Clinical Diagnostic Screening Model for Osteoporosis in Postmenopausal Women.

Age and weight are not only strong predictive parameters for osteoporosis diagnosis but can also be easily acquired from patients. This study aimed to develop and validate a new diagnostic screening model for postmenopausal osteoporosis that uses only 2 parameters, viz., age and weight. The discriminative ability of the model was analyzed and compared with that of the osteoporosis self-assessment tool for Asians (OSTA) index. The age-weight diagnostic screening model was developed using a retrospective chart review of postmenopausal women aged ≥50 years who underwent dual energy X-ray absorptiometry at a tertiary hospital from November 2017 to April 2022. Logistic regression analysis was used to derive a diagnostic screening model for osteoporosis. A total of 533 postmenopausal women were included in the study. According to the highest Youden index value, a probability cut-off value of 0.298 was used in the diagnosis screening model at any site, which yielded a sensitivity of 84.3% and a specificity of 53.8%. For increased sensitivity as a screening tool, a cut-off value of 0.254 was proposed to obtain a sensitivity of 90.2% and a specificity of 42.2%. The area under receiver operating characteristic curves from all screening models were significantly higher than those from the OSTA index model (p<0.05). This study showed the feasibility of a postmenopausal osteoporosis diagnostic screening model that uses 2 strong predictors for osteoporosis diagnosis: age and weight. This age-weight diagnostic model is a simple, effective option in postmenopausal osteoporosis screening.

CUL4A-mediated ZEB1/microRNA-340-5p/HMGB1 axis promotes the development of osteoporosis.

Understanding the molecular mechanisms underlying osteoclast differentiation provides insights into bone loss and even osteoporosis. The specific mechanistic actions of cullin 4A (CUL4A) in osteoclast differentiation and resultant osteoporosis is poorly explored. We developed a mouse model of osteoporosis using bilateral ovariectomy (OVX) and examined CUL4A expression. It was noted that CUL4A expression was increased in the bone marrow of OVX mice. Overexpression of CUL4A promoted osteoclast differentiation, and knockdown of CUL4A alleviated osteoporosis symptoms of OVX mice. Bioinformatic analyses were applied to identify the downstream target genes of microRNA-340-5p (miR-340-5p), followed by interaction analysis. The bone marrow macrophages (BMMs) were isolated from femur of OVX mice, which were transfected with different plasmids to alter the expression of CUL4A, Zinc finer E-box binding homeobox 1 (ZEB1), miR-340-5p, and Toll-like receptor 4 (TLR4). ChIP assay was performed to detect enrichment of ZEB1 promoter by H3K4me3 antibody in BMMs. ZEB1 was overexpressed in the bone marrow of OVX mice. Overexpression of CUL4A mediated H3K4me3 methylation to increase ZEB1 expression, thus promoting osteoclast differentiation. Meanwhile, ZEB1 could inhibit miR-340-5p expression and upregulate HMGB1 to induce osteoclast differentiation. Overexpressed ZEB1 activated the TLR4 pathway by regulating the miR-340-5p/HMGB1 axis to induce osteoclast differentiation, thus promoting the development of osteoporosis. Overall, E3 ubiquitin ligase CUL4A can upregulate ZEB1 to repress miR-340-5p expression, leading to HMGB1 upregulation and the TLR4 pathway activation, which promotes osteoclast differentiation and the development of osteoporosis.

Role of Mast-Cell-Derived RANKL in Ovariectomy-Induced Bone Loss in Mice.

Mast cells may contribute to osteoporosis development, because patients with age-related or post-menopausal osteoporosis exhibit more mast cells in the bone marrow, and mastocytosis patients frequently suffer from osteopenia. We previously showed that mast cells crucially regulated osteoclastogenesis and bone loss in ovariectomized, estrogen-depleted mice in a preclinical model for post-menopausal osteoporosis and found that granular mast cell mediators were responsible for these estrogen-dependent effects. However, the role of the key regulator of osteoclastogenesis, namely, receptor activator of NFκB ligand (RANKL), which is secreted by mast cells, in osteoporosis development has, to date, not been defined. Here, we investigated whether mast-cell-derived RANKL participates in ovariectomy (OVX)-induced bone loss by using female mice with a conditional Rankl deletion. We found that this deletion in mast cells did not influence physiological bone turnover and failed to protect against OVX-induced bone resorption in vivo, although we demonstrated that RANKL secretion was significantly reduced in estrogen-treated mast cell cultures. Furthermore, Rankl deletion in mast cells did not influence the immune phenotype in non-ovariectomized or ovariectomized mice. Therefore, other osteoclastogenic factors released by mast cells might be responsible for the onset of OVX-induced bone loss.

Biomimetic Porous Magnesium Alloy Scaffolds Promote the Repair of Osteoporotic Bone Defects in Rats through Activating the Wnt/β-Catenin Signaling Pathway.

In this study, biomimetic porous magnesium alloy scaffolds were prepared to repair femoral bone defects in ovariectomized osteoporotic rats. The purpose of the study was to investigate the effect of biomimetic porous magnesium alloy scaffolds on repairing osteoporotic bone defects and possible mechanisms. The animal model of osteoporosis was established in female SD rats. Three months later, a bone defect of 3 mm in diameter and 3 mm in depth was created in the lateral condyle of the right femur. The rats were then randomly divided into two groups: an experimental group and a control group. Four weeks after surgery, gross specimens were observed and micro-CT scans were performed. The repair of osteoporotic femoral defects in rats was studied histologically using HE staining, Masson staining, and Goldner staining. The expression of Wnt5a, β-catenin, and BMP-2 was measured between groups by immunohistochemical staining. The bone defect was repaired better after the application of biomimetic porous magnesium alloy scaffolds. Immunohistochemical results showed significantly higher expression of Wnt5a, β-catenin, and BMP-2. To conclude, the biomimetic porous magnesium alloy scaffolds proposed in this paper might promote the repair of osteoporotic femoral bone defects in rats possibly through activating the Wnt/β-catenin signaling pathway.

Anti‑metastatic activity of aromatic aminomethylidenebisphosphonates in a mouse model of 4T1 cell‑derived breast cancer.

Breast cancer is one of the major causes of cancer‑related mortality among women worldwide. It metastasizes to distant organs, particularly to bone tissue. Nitrogen‑containing bisphosphonates are mainly used as an adjuvant therapy to inhibit skeletal‑related events; however, there is increasing evidence to suggest that these compounds also exert antitumor effects. In previous studies, the authors synthesized two novel aminomethylidenebisphosphonates (BPs), namely benzene‑1,4‑bis[aminomethylidene(bisphosphonic)] acid (WG12399C) and naphthalene‑1,5‑bis[aminomethylidene(bisphosphonic)] acid (WG12592A). Both BPs exhibited notable antiresorptive activity in a mouse model of osteoporosis. The present study aimed to assess the invivo anticancer activity of WG12399C and WG12592A in 4T1 breast adenocarcinoma model. WG12399C exerted an anti‑metastatic effect by reducing the number of spontaneous lung metastases by ~66% in comparison to the control. In the experimental metastasis model of 4T1‑luc2‑tdTomato cells, this compound reduced the incidence of tumor metastases in the lungs by approximately half in comparison to the control. Both WG12399C and WG12595A also significantly reduced the size and/or number of bone metastatic foci. Their pro‑apoptotic and anti‑proliferative activity may, at least in part, explain the observed effects. Incubation with WG12399C induced an almost 6‑fold increase in caspase‑3 activity in 4T1 cells. Moreover, cells treated with WG12399C or WG12595A exhibited a 2‑fold reduction in invasiveness through Matrigel. Furthermore, both the BPs were able to sensitize the 4T1 cells to cytostatics. In summary, the results of the present study indicate that the examined aminomethylidene‑BPs may be of particular interest in the context of combined treatment in breast cancer therapy.

METTL14 represses osteoclast formation to ameliorate osteoporosis via enhancing GPX4 mRNA stability.

Excessive bone resorption by osteoclasts results in the development of multiple bone disorders including osteoporosis. This study aimed to explore the biological function of methyltransferase-like14 (METTL14) in osteoclast formation, as well as its related mechanisms. Expression levels of METTL14, GPX4 and osteoclast-related proteins TRAP, NFATc1, c-Fos were detected by qRT-PCR and Western blotting. The osteoporosis model was established in mice by bilateral ovariectomy (OVX). Bone histomorphology was determined by micro-CT and H&E staining. NFATc1 expression in bone tissues was determined by immunohistochemical staining. Proliferation of primary bone marrow macrophages cells (BMMs) was assessed by MTT assay. Osteoclast formation was observed by TRAP staining. The regulatory mechanism was evaluated by RNA methylation quantification assay, MeRIP-qPCR, dual luciferase reporter assay, and RIP, respectively. METTL14 was down-regulated in the serum samples of postmenopausal osteoporotic women, which was positively associated with bone mineral density (BMD). Osteoclast formation was promoted in OVX-treated METTL14+/- mice as compared with wild-type littermates. Conversely, METTL14 overexpression repressed RANKL-induced osteoclast differentiation of BMMs. Mechanistically, METTL14-mediated m6A modification post-transcriptionally stabilized glutathione peroxidase 4 (GPX4), with the assistance of Hu-Antigen R (HuR). Finally, GPX4 depletion-mediated osteoclast formation in BMMs could be counteracted by METTL14 or HuR overexpression. Collectively, METTL14 inhibits osteoclastogenesis and bone resorption via enhancing GPX4 stability through an m6A-HuR dependent mechanism. Therefore, targeting METTL14 might be a novel promising treatment strategy for osteoporosis.

Vitexin loaded mixed polymeric micelles: preparation, optimization, evaluation and anti-osteoporotic effect

In this regard, we developed vitexin (Vi)-loaded D-ɑ-tocopherol polyethylene glycol succinate, polyvinylpyrrolidone K30 and sodium cholate mixed micelles (Vi-MMs) mainly for improving oral bioavailability and enhancing anti-osteoporotic effect of Vi. Thin layer dispersion method was employed to prepare Vi-MMs, and then the optimal prescription was optimized by the orthogonal design-response surface method, wherein encapsulation efficiency (EE) was used as optimizing index. The physical properties of Vi-MMs such as appearance morphology, particle size, and zeta potential were also characterized. We further analyzed the in-vitro release of Vi and Vi-MMs in three media and investigated the pharmacokinetics of Vi and Vi-MMs in rats. Anti-osteoporotic activity of Vi and Vi-MMs was assessed by establishing a zebrafish osteoporosis model with prednisone. Drug loading, EE, particle size and zeta potential of the optimized Vi-MMs were 8.58 ± 0.13%, 93.86 ± 1.79%, 20.41 ± 0.64 nm and −10 ± 0.56 mV, respectively. The optimized Vi-MMs were shaped spherically as exhibited by transmission electron microscopic technique, with evident core shell nano-structure, well dispersed. In all three media, the release rate of Vi-MMs was significantly higher than that of free Vi. The oral bioavailability of Vi-MMs was increased by 5.6-fold compared to free Vi. In addition, alleviation of prednisone induced osteoporosis in zebrafish by Vi-MMs further demonstrated good anti-osteoporotic effect. In summary, Vi-MMs exhibited enhanced bioavailability and anti-osteoporotic effect, which is expected to be potential nanocarrier for Vi applications in drug development.

Reduced APPL1 impairs osteogenic differentiation of mesenchymal stem cells by facilitating MGP expression to disrupt the BMP2 pathway in osteoporosis

An imbalance of human mesenchymal stem cells (MSCs) adipogenic and osteogenic differentiation plays an important role in the pathogenesis of osteoporosis. Our previous study verified that Adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1)/myoferlin deficiency promotes adipogenic differentiation of MSCs by blocking autophagic flux in osteoporosis. However, the function of APPL1 in the osteogenic differentiation of MSCs remains unclear. This study aimed to investigate the role of APPL1 in the osteogenic differentiation of MSCs in osteoporosis and the underlying regulatory mechanism. In this study, we demonstrated the downregulation of APPL1 expression in patients with osteoporosis and osteoporosis mice. The severity of clinical osteoporosis was negatively correlated with the expression of APPL1 in bone marrow MSCs. We found that APPL1 positively regulates the osteogenic differentiation of MSCs invitro and invivo. Moreover, RNA sequencing showed that the expression of MGP, an osteocalcin/matrix Gla family member, was significantly upregulated after APPL1 knockdown. Mechanistically, our study showed that reduced APPL1 impaired the osteogenic differentiation of mesenchymal stem cells by facilitating Matrix Gla protein expression to disrupt the BMP2 pathway in osteoporosis. We also evaluated the significance of APPL1 in promoting osteogenesis in a mouse model of osteoporosis. These results suggest that APPL1 may be an important target for the diagnosis and treatment of osteoporosis.

Application of machine learning algorithms to predict osteoporosis in postmenopausal women with type 2 diabetes mellitus.

The screening and diagnosis of osteoporosis in patients with type 2 diabetes mellitus (T2DM) based on bone mineral density remains challenging because of the limited availability and accessibility of dual-energy X-ray absorptiometry. We aimed to develop and validate models to predict the risk of osteoporosis in postmenopausal women with T2DM based on machine learning (ML) algorithms. This retrospective study included 303 postmenopausal women with T2DM. To develop prediction models for osteoporosis, we applied nine ML algorithms combined with demographic, clinical, and laboratory data. The least absolute shrinkage and selection operator were used to perform feature selection. We used the bootstrap resampling technique for model training and validation. To test the performance of the models, we calculated indices including the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, F1 score, calibration curve, and decision curve analysis. Furthermore, we conducted fivefold cross-validation for parameter optimization and model validation. Feature importance was assessed using the SHapley additive explanation (SHAP). We identified 10 independent predictors as the most valuable features. An AUROC of 0.616-1.000 was observed for nine ML algorithms. The extreme gradient boosting (XGBoost) model exhibited the best performance, outperforming conventional risk assessment tools and registering 0.993 in the training set, 0.798 in the validation set, and 0.786 in the test set for fivefold cross-validation. Using SHAP, we found that the explanatory variables contributed to the model and their relationship with osteoporosis occurrence. Furthermore, we developed a user-friendly tool for calculating the risk of osteoporosis. With the integration of demographic and clinical risk factors, ML algorithms can accurately predict osteoporosis. The XGBoost model showed ideal performance. With the incorporation of these models in the clinic, patients may benefit from early osteoporosis diagnosis and treatment.

Adjuvant rice optimization of rice-steamed Rehmanniae Radix and its anti-osteoporosis effect

The present study aimed to investigate the effect of various adjuvant rice on the quality of rice-steamed Rehmanniae Radix(RSRR) with Japonica rice, millet, yellow rice, black rice, and glutinous rice as raw materials, and analyze the anti-osteoporosis effect of RSRR by the optimal adjuvant rice. On the basis of the established UPLC-MS/MS method for the determination of the content of catalpol and rehmannioside D, comprehensive weighted scoring method was employed to evaluate the effect of various auxiliary rice on the quality of RSRR with the content of catalpol and rehmannioside D, character score, and taste score as indicators to optimize adjuvant rice. The osteoporosis model was induced by ovariectomy in rats. SD rats were randomly divided into a sham operation group, a model group, a positive control group, and low-dose and high-dose groups of Rehmanniae Radix, RSRR, steamed Rehmanniae Radix, and Epimedii Folium-RSRR. After treatment for 12 weeks, body weight, bone calcium content, and bone mineral density were mea-sured. The results showed that Japonica rice was selected as the optimal adjuvant due to the highest comprehensive score of RSRR steamed by Japonica rice. Rehmanniae Radix, RSRR, steamed Rehmanniae Radix, as well as Epimedii Folium-RSRR, could improve osteoporosis by increasing bone calcium content and bone mineral density. RSRR was superior to Rehmanniae Radix in improving osteo-porosis. However, there was no significant difference between RSRR and steamed Rehmanniae Radix. This study confirmed that Japo-nica rice was the optimal adjuvant rice of RSRR and verified the anti-osteoporosis effect of RSRR, which laid a foundation for further research on the pharmacological action and mechanism of RSRR.

SIRT2 regulates extracellular vesicle-mediated liver–bone communication

The interplay between liver and bone metabolism remains largely uncharacterized. Here, we uncover a mechanism of liver-bone crosstalk regulated by hepatocyte SIRT2. We demonstrate that hepatocyte SIRT2 expression is increased in aged mice and elderly humans. Liver-specific SIRT2 deficiency inhibits osteoclastogenesis and alleviates bone loss in mouse models of osteoporosis. We identify leucine-rich α-2-glycoprotein 1 (LRG1) as a functional cargo in hepatocyte-derived small extracellular vesicles (sEVs). In SIRT2-deficient hepatocytes, LRG1 levels in sEVs are upregulated, leading to increased transfer of LRG1 to bone-marrow-derived monocytes (BMDMs), and in turn, to inhibition of osteoclast differentiation via reduced nuclear translocation of NF-κB p65. Treatment with sEVs carrying high levels of LRG1 inhibits osteoclast differentiation in human BMDMs and in mice with osteoporosis, resulting in attenuated bone loss in mice. Furthermore, the plasma level of sEVs carrying LRG1 is positively correlated with bone mineral density in humans. Thus, drugs targeting hepatocyte-osteoclast communication may constitute a promising therapeutic strategy for primary osteoporosis.

The effect of pharmacological treatment in combination with vitamin K on healing in an experimental rat model of osteoporosis.

This study aims to compare the effects of teriparatide, zoledronic acid, and their combination therapy with vitamin K on osteoporotic rats. We divided a total of 50 female Sprague-Dawley rats into five groups: A (the control group), B and D (the teriparatide group), and C and E (the zoledronic acid group). Following ovariectomy and subcutaneous heparin administration at a dose of 2 IU/kg for four weeks, osteoporosis was created. Groups A, B, and C were fed with standard feed, while Groups D and E were fed with vitamin K-rich feed. After four weeks of treatment, sacrification was performed. The right and left femurs were separated for histopathological and biomechanical evaluation, respectively. For histopathological evaluation, the femurs were decalcified, and the sections were stained with hematoxylin-eosin and evaluated under a light microscope. Fracture healing was evaluated using the classification system as described previously. For biomechanical evaluation, the 3-point stress test and torsion stress test were applied to 10 femurs from each group. Groups B-E were histopathologically and biomechanically superior to Group A in fracture healing of osteoporotic rats; however, it was not statistically significant (p>0.05). The group that received additional vitamin K was histopathologically and biomechanically superior to the group which was fed with standard feed, although it was not statistically significant (p>0.05). Our study results indicated that both teriparatide and zoledronic acid had beneficial effects on osteoporotic fractures with comparable histological and biochemical results. Vitamin K promoted teriparatide and zoledronic acid treatment on osteoporotic fracture healing. Based on these findings, combination therapies may yield the most optimal results in biomechanical and histological examinations.

Non-psychoactive Cannabidiol Prevents Osteoporosis in an Animal Model and Increases Cell Viability, Proliferation, and Osteogenic Gene Expression in Human Skeletal Stem and Progenitor Cells.

Cannabidiol (CBD), the non-psychoactive component of the Cannabis sativa plant, is marketed as a potential therapeutic agent and has been studied for its roles in reducing inflammation and managing neuropathic pain. Some studies have reported that CB1 and CB2 receptor activation can attenuate and reverse bone loss in experimental animal models. Despite this, little is known about the impact of CBD on fracture healing. We investigated the effects of CBD in vitro using human osteoprogenitor cells and in vivo via murine femur fracture and osteoporosis models. In vitro mesenchymal stem cells were treated with increasing concentrations of crystalized pharmaceutical grade CBD or vehicle solution. Cell viability and proliferation were significantly increased in cells treated with CBD compared to vehicle control. Osteocalcin expression was also significantly higher in the CBD-treated human stem cells compared to vehicle control. In vivo the effect of CBD on bone mineral density and fracture healing in mice was examined using a two-phase experimental approach. Fluoxetine was used for pharmacologic induction of osteoporosis and surgical oophorectomy (OVX) was used for hormonal induction of osteoporosis. X-ray and microCT analysis showed that CBD prevented both fluoxetine- and OVX-induced osteoporosis. We found that while OVX resulted in delayed bone healing in control mice, CBD-pretreated mice exhibited normal bone healing. Collectively these in vitro and in vivo findings suggest that CBD exerts cell-specific effects which can be exploited to enhance bone metabolism. These findings also indicate that CBD usage in an osteoporotic population may positively impact bone morphology, warranting further research.

Protective effects of polydatin against bone and joint disorders: the in vitro and in vivo evidence so far.

Polydatin is an active polyphenol displaying multifaceted benefits. Recently, growing studies have noticed its potential therapeutic effects on bone and joint disorders (BJDs). Therefore, this article reviews recent in vivo and in vitro progress on the protective role of polydatin against BJDs. An insight into the underlying mechanisms is also presented. It was found that polydatin could promote osteogenesis in vitro, and symptom improvements have been disclosed with animal models of osteoporosis, osteosarcoma, osteoarthritis and rheumatic arthritis. These beneficial effects obtained in laboratory could be mainly attributed to the bone metabolism-regulating, anti-inflammatory, antioxidative, apoptosis-regulating and autophagy-regulating functions of polydatin. However, studies on human subjects with BJDs that can lead to early identification of the clinical efficacy and adverse effects of polydatin have not been reported yet. Accordingly, this review serves as a starting point for pursuing clinical trials. Additionally, future emphasis should also be devoted to the low bioavailability and prompt metabolism nature of polydatin. In summary, well-designed clinical trials of polydatin in patients with BJD are in demand, and its pharmacokinetic nature must be taken into account.