Osteoporosis therapies and their mechanisms of action (Review)

Enhancing osteoporosis treatment using a targeted, sustained-release drug delivery system based on macrocyclic amphiphile

Osteoporosis, a prevalent systemic bone metabolic disorder, primarily affects postmenopausal women and is characterized by increased bone fragility and a heightened risk of fractures. The efficacy of current osteoporosis treatments is often limited by non-specific drug targeting and undesirable off-target skeletal side effects. To address this challenge, we have developed a novel hydroxyapatite-responsive drug delivery system. This system utilizes a self-assembled p-phosphonatocalix[4]arene tetradodecyl ether (PC4A12C), engineered to specifically target and sustain the release of osteoporosis medication at sites of bone remodeling. Our focus centers on icariin (ICA), a drug known for its potent osteogenic properties and minimal adverse effects. In vitro, ICA-loaded PC4A12C (ICA@PC4A12C) demonstrated enhanced proliferation, differentiation, and mineralization in bone marrow mesenchymal stem cells (BMSCs). In vivo, ICA@PC4A12C exhibited superior efficacy in specifically targeting bone tissue, ensuring a controlled and slow release of icariin directly within the bone environment. In an osteoporosis mouse model, treatment with ICA@PC4A12C showed notable enhancement in osteogenic activity and a significant increase in bone density compared to ICA alone. These results demonstrate the potential of PC4A12C as an effective drug carrier in the development of advanced antiosteoporotic drug delivery systems.

Pro-Osteogenic Effect of the Nutraceutical BlastiMin Complex® in Women with Osteoporosis or Osteopenia: An Open Intervention Clinical Trial

Osteoporosis is a chronic disease that affects millions of patients worldwide and is characterized by low bone mineral density (BMD) and increased risk of fractures. Notably, natural molecules can increase BMD and exert pro-osteogenic effects. Noteworthily, the nutraceutical BlastiMin Complex® (Mivell, Italy, European Patent Application EP4205733A1) can induce differentiation of human bone marrow mesenchymal stem cells (BM-MSCs) in osteoblasts and can exert in vitro pro-osteogenic and anti-inflammatory effects. Thus, the purpose of this study was to verify the effects of BlastiMin Complex® on bone turnover markers (BTMs) and BMD in patients with senile and postmenopausal osteopenia or osteoporosis. The efficacy of BlastiMin Complex® on BTMs in serum was evaluated through biochemical assays. BMD values were analyzed by dual-energy X-ray absorptiometry (DXA) and Radiofrequency Echographic Multi Spectrometry (R.E.M.S.) techniques, and the SNPs with a role in osteoporosis development were evaluated by PCR. Clinical data obtained after 12 months of treatment showed an increase in bone turnover index, a decrease in C-reactive protein levels, and a remarkable increase in P1NP levels, indicating the induction of osteoblast proliferation and activity in the cohort of 100% female patients recruited for the study. These findings show that the nutraceutical BlastiMin Complex® could be used as an adjuvant in combination with synthetic drugs for the treatment of osteoporosis pathology.

Estrogen and estrogen receptors mediate the mechanobiology of bone disease and repair

It is well understood that the balance of bone formation and resorption is dependent on both mechanical and biochemical factors. In addition to cell-secreted cytokines and growth factors, sex hormones like estrogen are critical to maintaining bone health. Although the direct osteoprotective function of estrogen and estrogen receptors (ERs) has been reported extensively, evidence that estrogen signaling also has a role in mediating the effects of mechanical loading on maintenance of bone mass and healing of bone injuries has more recently emerged. Recent studies have underscored the role of estrogen and ERs in many pathways of bone mechanosensation and mechanotransduction. Estrogen and ERs have been shown to augment integrin-based mechanotransduction as well as canonical Wnt/b-catenin, RhoA/ROCK, and YAP/TAZ pathways. Estrogen and ERs also influence the mechanosensitivity of not only osteocytes but also osteoblasts, osteoclasts, and marrow stromal cells. The current review will highlight these roles of estrogen and ERs in cellular mechanisms underlying bone mechanobiology and discuss their implications for management of osteoporosis and bone fractures. A greater understanding of the mechanisms behind interactions between estrogen and mechanical loading may be crucial to addressing the shortcomings of current hormonal and pharmaceutical therapies. A combined therapy approach including high-impact exercise therapy may mitigate adverse side effects and allow an effective long-term solution for the prevention, treatment, and management of bone fragility in at-risk populations. Furthermore, future implications to novel local delivery mechanisms of hormonal therapy for osteoporosis treatment, as well as the effects on bone health of applications of sex hormone therapy outside of bone disease, will be discussed.

In vitro and in vivo studies on exogenous polyamines and α-difluoromethylornithine to enhance bone formation and suppress osteoclast differentiation

Exogenous polyamines, including putrescine (PUT), spermidine (SPD), and spermine (SPM), and the irreversible inhibitor of the rate-limiting enzyme ornithine decarboxylase (ODC) of polyamine biosynthesis, α-difluoromethylornithine (DFMO), are implicated as stimulants for bone formation. We demonstrate in this study the osteogenic potential of exogenous polyamines and DFMO in human osteoblasts (hOBs), murine monocyte cell line RAW 264.7, and an ovariectomized rat model. The effect of polyamines and DFMO on hOBs and RAW 264.7 cells was studied by analyzing gene expression, alkaline phosphatase (ALP) activity, tartrate-resistant acid phosphatase (TRAP) activity, and matrix mineralization. Ovariectomized rats were treated with polyamines and DFMO and analyzed by micro computed tomography (micro CT). The mRNA level of the early onset genes of osteogenic differentiation, Runt-related transcription factor 2 (Runx2) and ALP, was significantly elevated in hOBs under osteogenic conditions, while both ALP activity and matrix mineralization were enhanced by exogenous polyamines and DFMO. Under osteoclastogenic conditions, the gene expression of both receptor activator of nuclear factor-κB (RANK) and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) was reduced, and TRAP activity was suppressed by exogenous polyamines and DFMO in RAW 264.7 cells. In an osteoporotic animal model of ovariectomized rats, SPM and DFMO were found to improve bone volume in rat femurs, while trabecular thickness was increased in all treatment groups. Results from this study provide in vitro and in vivo evidence indicating that polyamines and DFMO act as stimulants for bone formation, and their osteogenic effect may be associated with the suppression of osteoclastogenesis.

Bioequivalence of Recombinant Human Teriparatide Injection in Healthy Adult Female Subjects in the Fasting State

A single-center, randomized, open, 2-period, self-crossover, single-dose trial was conducted to evaluate the bioequivalence of the test (T) and reference (R) preparations in healthy adult female subjects under fasting conditions. Seventy-six subjects were enrolled in the study, and subjects were randomly divided into 2 groups at a 1:1 ratio and were administered once per period, with a 4-day washout period. In each period, plasma drug concentrations, blood calcium changes, and antibodies were determined for pharmacokinetics, pharmacodynamics, and immunogenicity analysis, respectively, and adverse events were recorded for safety analysis. The 90% confidence intervals for the geometric mean ratios (T:R) of maximum plasma concentration, area under the plasma concentration-time curve from time 0 to the last measurable concentration, and area under the plasma concentration-time curve from time 0 to infinity were within the predefined bioequivalence criterion of 80%-125%, indicating bioequivalence between the T and R preparations under fasting conditions. Comparable serum calcium levels demonstrated pharmacodynamics similarity, and no differences were found in immunogenicity profiles. Additionally, the incidence of adverse reactions to the T preparation was 18.4% lower than that of the R preparation (31.6%). This study confirmed the bioequivalence of the T and R preparations under fasting conditions, along with comparable immunogenicity profiles and good safety.

The novel small molecule E0924G dually regulates bone formation and bone resorption through activating the PPARδ signaling pathway to prevent bone loss in ovariectomized rats and senile mice

Osteoporosis is particularly prevalent among postmenopausal women and the elderly. In the present study, we investigated the effect of the novel small molecule E0924G (N-(4-methoxy-pyridine-2-yl)-5-methylfuran-2-formamide) on osteoporosis. E0924G significantly increased the protein expression levels of osteoprotegerin (OPG) and runt-related transcription factor 2 (RUNX2), and thus significantly promoted osteogenesis in MC3T3-E1 cells. E0924G also significantly decreased osteoclast differentiation and inhibited bone resorption and F-actin ring formation in receptor activator of NF-κB ligand (RANKL)-induced osteoclasts from RAW264.7 macrophages. Importantly, oral administration of E0924G in both ovariectomized (OVX) rats and SAMP6 senile mice significantly increased bone mineral density and decreased bone loss compared to OVX controls or SAMR1 mice. Further mechanistic studies showed that E0924G could bind to and then activate peroxisome proliferator-activated receptor delta (PPARδ), and the pro-osteoblast effect and the inhibition of osteoclast differentiation induced by E0924G were significantly abolished when PPARδ was knocked down or inhibited. In conclusion, these data strongly suggest that E0924G has the potential to prevent OVX-induced and age-related osteoporosis by dual regulation of bone formation and bone resorption through activation of the PPARδ signaling pathway.

Suppression of bone resorption by Mori Radicis Cortex through NFATc1 and c-Fos signaling-mediated inhibition of osteoclast differentiation

BACKGROUND

Mori Radicis Cortex (MRC) is the root bark of the mulberry family as Morus alba L. In Korea, it is known as "Sangbaegpi". Although MRC has demonstrated anti-inflammatory and antioxidant effects, its specific mechanisms of action and impact on osteoporosis remain poorly understood.

METHODS

To investigate the antiosteoporosis effect of MRC, we examined the level of osteoclast differentiation inhibition in receptor activator of nuclear factor kappa-Β ligand (RANKL)-induced-RAW 264.7 cells and animal models of ovariectomy (OVX) with MRC. Serum analysis in OVX animals was investigated by enzyme-linked immunosorbent assay (ELISA), and bone density analysis was confirmed by micro-computed tomography (micro-CT). The expression analysis of nuclear factor of activated T cells 1 (NFATc1) was confirmed by immunohistochemistry (IHC) in femur tissue. In addition, osteoclast differentiation inhibition was measured using tartrate-resistant acid phosphatase (TRAP). mRNA analysis was performed using reverse transcription-polymerase chain reaction (RT-PCR), and the protein expression analysis was investigated by western blot.

RESULTS

Micro-CT analysis showed that MRC effectively inhibited bone loss in the OVX-induced rat model. MRC also inhibited the expression of alkaline phosphatase (ALP) and TRAP in serum. Histological analysis showed that MRC treatment increased bone density and IHC analysis showed that MRC significantly inhibited the expression of NFATc1. In RANKL-induced-RAW 264.7 cells, MRC significantly reduced TRAP activity and actin ring formation. In addition, MRC significantly inhibited the expression of NFATc1 and c-Fos, and suppressed the mRNA expression.

CONCLUSION

Based on micro-CT, serum and histological analysis, MRC effectively inhibited bone loss in an OVX-induced rat model. In addition, MRC treatment suppressed the expression of osteoclast differentiation, fusion, and bone resorption markers through inhibition of NFATc1/c-Fos expression in RANKL-induced RAW 264.7 cells, ultimately resulting in a decrease in osteoclast activity. These results demonstrate that MRC is effective in preventing bone loss through inhibiting osteoclast differentiation and activity.

Nutraceuticals and Functional Foods: A Comprehensive Review of Their Role in Bone Health

Bone health is the result of a tightly regulated balance between bone modeling and bone remodeling, and alterations of these processes have been observed in several diseases both in adult and pediatric populations. The imbalance in bone remodeling can ultimately lead to osteoporosis, which is most often associated with aging, but contributing factors can already act during the developmental age, when over a third of bone mass is accumulated. The maintenance of an adequate bone mass is influenced by genetic and environmental factors, such as physical activity and diet, and particularly by an adequate intake of calcium and vitamin D. In addition, it has been claimed that the integration of specific nutraceuticals such as resveratrol, anthocyanins, isoflavones, lycopene, curcumin, lutein, and β-carotene and the intake of bioactive compounds from the diet such as honey, tea, dried plums, blueberry, and olive oil can be efficient strategies for bone loss prevention. Nutraceuticals and functional foods are largely used to provide medical or health benefits, but there is an urge to determine which products have adequate clinical evidence and a strong safety profile. The aim of this review is to explore the scientific and clinical evidence of the positive role of nutraceuticals and functional food in bone health, focusing both on molecular mechanisms and on real-world studies.

Efficacy of Opportunistic Screening with Chest CT in Identifying Osteoporosis and Osteopenia in Patients with T2DM

Purpose

To explore the validity of the thoracic spine Hounsfield Unit (HU) measured by chest computed tomography (CT) for opportunistic screening of diabetic osteoporosis. The current study attempted to establish a diagnostic threshold for thoracic spine HU in a type 2 diabetes mellitus (T2DM) population with osteoporosis.

Patients and Methods

The current study retrospectively included 334 patients with T2DM. They underwent chest CT and Dual-energy X-ray (DXA) between August 2021 and January 2022 in our hospital. HU values were measured on the resulting chest CT images at thoracic spine 11 and 12 to construct regions of interest. All patients were grouped according to the lowest T-value of DXA examination: osteoporosis, osteopenia and normal bone density. HU values were compared with T-values in each group of patients, and receiver operating characteristics curves were plotted to calculate diagnostic thresholds as well as sensitivity and specificity.

Results

There was a strong correlation between the HU values of chest CT and the T-values of DXA (p < 0.01). The sensitivity for osteoporosis was 88.7% for T11 attenuation≤ 98 HU and the specificity for osteoporosis was 87.5% for T12 attenuation ≤ 117HU; the specificity for normal BMD was 85.4% for T11 attenuation ≥ 147 HU and 82% for T12 attenuation ≥ 146 HU.

Conclusion

Chest CT can be used to screen patients with T2DM for opportunistic osteoporosis and help determine if they need DXA screening. The current study suggests that when the HU threshold of T11 ≤ 98/T12 ≤ 117, patients may need further osteoporosis screening.

A comprehensive review and advanced biomolecule-based therapies for osteoporosis

BACKGROUND

The prevalence of osteoporosis (OP) on a global scale is significantly elevated that causes life threatening issues. The potential of groundbreaking biomolecular therapeutics in the field of OP is highly encouraging. The administration of biomolecular agents has the potential to mitigate the process of bone demineralization while concurrently augmenting the regenerative capacity of bone tissue, thereby facilitating a personalized therapeutic approach. Biomolecules-based therapies showed promising results in term of bone mass protection and restoration in OP.

AIM OF REVIEW

We summarized the recent biomolecular therapies with notable progress in clinical, demonstrating the potential to transform illness management. These treatments frequently utilize different biomolecule based strategies. Biomolecular therapeutics has a targeted character, which results in heightened specificity and less off-target effects, ultimately leading to increased patient outcomes. These aspects have the capacity to greatly enhance the management of OP, thus resulting in a major enhancement in the quality of life encountered by individuals affected by this condition.

Therapeutic avenues in bone repair: Harnessing an anabolic osteopeptide, PEPITEM, to boost bone growth and prevent bone loss

The existing suite of therapies for bone diseases largely act to prevent further bone loss but fail to stimulate healthy bone formation and repair. We describe an endogenous osteopeptide (PEPITEM) with anabolic osteogenic activity, regulating bone remodeling in health and disease. PEPITEM acts directly on osteoblasts through NCAM-1 signaling to promote their maturation and formation of new bone, leading to enhanced trabecular bone growth and strength. Simultaneously, PEPITEM stimulates an inhibitory paracrine loop: promoting osteoblast release of the decoy receptor osteoprotegerin, which sequesters RANKL, thereby limiting osteoclast activity and bone resorption. In disease models, PEPITEM therapy halts osteoporosis-induced bone loss and arthritis-induced bone damage in mice and stimulates new bone formation in osteoblasts derived from patient samples. Thus, PEPITEM offers an alternative therapeutic option in the management of diseases with excessive bone loss, promoting an endogenous anabolic pathway to induce bone remodeling and redress the imbalance in bone turnover.

Anti-osteoporotic treatments in the era of non-alcoholic fatty liver disease: friend or foe

Over the last years non-alcoholic fatty liver disease (NAFLD) has grown into the most common chronic liver disease globally, affecting 17-38% of the general population and 50-75% of patients with obesity and/or type 2 diabetes mellitus (T2DM). NAFLD encompasses a spectrum of chronic liver diseases, ranging from simple steatosis (non-alcoholic fatty liver, NAFL) and non-alcoholic steatohepatitis (NASH; or metabolic dysfunction-associated steatohepatitis, MASH) to fibrosis and cirrhosis with liver failure or/and hepatocellular carcinoma. Due to its increasing prevalence and associated morbidity and mortality, the disease-related and broader socioeconomic burden of NAFLD is substantial. Of note, currently there is no globally approved pharmacotherapy for NAFLD. Similar to NAFLD, osteoporosis constitutes also a silent disease, until an osteoporotic fracture occurs, which poses a markedly significant disease and socioeconomic burden. Increasing emerging data have recently highlighted links between NAFLD and osteoporosis, linking the pathogenesis of NAFLD with the process of bone remodeling. However, clinical studies are still limited demonstrating this associative relationship, while more evidence is needed towards discovering potential causative links. Since these two chronic diseases frequently co-exist, there are data suggesting that anti-osteoporosis treatments may affect NAFLD progression by impacting on its pathogenetic mechanisms. In the present review, we present on overview of the current understanding of the liver-bone cross talk and summarize the experimental and clinical evidence correlating NAFLD and osteoporosis, focusing on the possible effects of anti-osteoporotic drugs on NAFLD.

Exploring epigenetic strategies for the treatment of osteoporosis

The worldwide trend toward an aging population has resulted in a higher incidence of chronic conditions, such as osteoporosis. Osteoporosis, a prevalent skeletal disorder characterized by decreased bone mass and increased fracture risk, encompasses primary and secondary forms, each with distinct etiologies. Mechanistically, osteoporosis involves an imbalance between bone resorption by osteoclasts and bone formation by osteoblasts. Current pharmacological interventions for osteoporosis, such as bisphosphonates, denosumab, and teriparatide, aim to modulate bone turnover and preserve bone density. Hormone replacement therapy and lifestyle modifications are also recommended to manage the condition. While current medications offer therapeutic options, they are not devoid of limitations. Recent studies have highlighted the importance of epigenetic mechanisms, including DNA methylation and histone modifications, in regulating gene expression during bone remodeling. The use of epigenetic drugs, or epidrugs, to target these mechanisms offers a promising avenue for therapeutic intervention in osteoporosis. In this review, we comprehensively examine the recent advancements in the application of epidrugs for treating osteoporosis.

2,4'-Dihydroxybenzophenone Exerts Bone Formation and Antiosteoporotic Activity by Stimulating the β-Catenin Signaling Pathway

2,4'-Dihydroxybenzophenone (DHP) is an organic compound derived from Garcinia xanthochymus, but there have been no reports on its biochemical functions and bioavailability. In this study, we evaluated whether DHP affects osteoblast differentiation and activation in MC3T3-E1 preosteoblast cells, as well as antiosteoporotic activity in zebrafish larvae. Nontoxic concentrations of DHP-treated MC3T3-E1 preosteoblast cells increased alkaline phosphatase (ALP) activation and mineralization in a concentration-dependent manner, accompanied by higher expression of osteoblast-specific markers, including Runt-related transcription factor 2 (RUNX2), osterix, and ALP. Consistent with the data in MC3T3-E1 preosteoblast cells, DHP upregulated osteoblast-specific marker genes in zebrafish larvae and simultaneously enhanced vertebral formation. We also revealed that DHP increased the phosphorylation of glycogen synthase kinase-3β (GSK-3β) at Ser9 and the total expression of β-catenin in the cytosol and markedly increased the localization of β-catenin into the nucleus. Furthermore, DHP restored the prednisolone (PDS)-induced marked decrease in ALP activity and mineralization, as well as osteoblast-specific marker expression. In PDS-treated zebrafish, DHP also alleviated PDS-induced osteoporosis by restoring vertebral formation and osteoblast-related gene expression. Taken together, these results suggest that DHP is a potential osteoanabolic candidate for treating osteoporosis by stimulating osteoblast differentiation.

Study on the mechanism of naringin in promoting bone differentiation: In vitro and in vivo study

Objective

Osteoporosis is a common clinical bone disease that occurs most frequently in middle-aged and elderly people. Various traditional herbal medicine formulations have shown significant benefits in models of osteoporosis. In this study, we aim to investigate the osteogenic efficacy of naringin (NRG) in the osteoporotic state.

Design

We treated Bone marrow stromal cells (BMSCs) with various concentrations of NRG for 3 and 7 days. BMSC proliferation was measured by the MTT assay. The effect of NRG on the osteogenic differentiation of BMSCs was detected by ALP and alizarin red staining. The effect of NRG on the BMP2/Runx2/Osterix signaling pathway was analyzed by using real-time PCR. The effect of NRG on the oestrogen receptor was measured by Enzyme-linked immunosorbent assay. In vivo animal experiments were performed by micro-computed tomography and ALP immunohistochemistry to determine the ectopic osteogenic effect of NRG sustained-release nanoparticles in a mouse model of osteoporosis.

Results

NRG promoted the proliferation and osteogenic differentiation of BMSCs. Moreover, it also activated the BMP2/Runx2/Osterix signaling pathway. When NRG sustained-release nanoparticles were added in vivo in animal experiments, we found that NRG sustained-release nanoparticles had better ectopic osteogenic effects in a mouse model of osteoporosis.

Conclusions

NRG induced osteoblastic differentiation of BMSCs by activating the BMP2/Runx2/Osterix signaling pathway and promoted the regulation of oestrogen receptor pathway protein expression, and NRG sustained-release nanoparticles exerted a more significant in vivo ectopic osteogenic effect in an osteoporosis mouse model. Therefore, naringin is expected to be developed as a novel treatment for inducing osteogenesis, because of its ubiquitous, cost-efficient, and biologically active characteristics. However, further research is needed on how to improve the pharmacokinetic properties of naringin and its specific mechanism.

Osteoporosis therapy using nanoparticles: a review

Osteoporosis, characterized by low bone density and increased risk of fractures, represents a major healthcare challenge. Anti-resorptive and anabolic medications are now used to treat osteoporosis in an effort to reduce bone loss and increase bone mass. Innovative methods are required since current therapies have drawbacks. Promising options for improving bone health and medicine delivery are provided by nanotechnology. Bisphosphonates with tetracyclines and oligopeptides, among other compounds that target the bone, make it easier to provide a particular medication to bone tissue. Additionally, nanocarriers are essential for the administration of both organic and inorganic nanoparticles in the treatment of osteoporosis. Drug encapsulation and controlled release may be done in a variety of ways using organic nanoparticles. Inorganic nanoparticles have special qualities that help in medication transport and bone repair. This review explores the potential of nanoparticle-based strategies in the treatment of osteoporosis.

What is the evidence for the effect of physical exercise on bone health in menopausal women? An umbrella systematic review

This study aimed to analyze the effects of physical exercise (PE) on bone health in menopausal women through an umbrella review and to assess the quality of systematic reviews (SRs) and meta-analyses (MAs) included. The review was registered in PROSPERO (CRD42020208130) and the Rayyan application was used. The methodological quality of the included studies was evaluated by A MeaSurement Tool to Assess Systematic Reviews (AMSTAR), and Grading of Recommendations Assessment, Development and Evaluation (GRADE) was applied to assess the level of evidence of the results. The results showed that low-intensity jumping exercises with longer sessions proved to be efficient in the hip segment. Swimming requires further investigation, as it showed high heterogeneity. Aerobic and resistance exercises showed inconsistent results, requiring further studies with these modalities of PE. Concurrent training showed improvements in the lumbar spine, femoral neck, Ward's triangle and trochanter. Finally, combined resistance exercises are effective in preserving bone mineral density (BMD) of the femoral neck and lumbar spine in postmenopausal women. In conclusion, jumping exercises were efficient in the hip, while aerobic and resistance exercises are still inconsistent. Concurrent training showed improvements in BMD of the lumbar spine, femoral neck, Ward's triangle and trochanter. Finally, combined resistance protocols are effective in preserving BMD of the femoral neck and lumbar spine in postmenopausal women.

MiR-210 promotes bone formation in ovariectomized rats by regulating osteogenic/adipogenic differentiation of bone marrow mesenchymal stem cells through downregulation of EPHA2

PURPOSE

In osteoporosis, the balance between osteogenic and adipogenic differentiation of mesenchymal stem cells (MSCs) is disrupted. The osteogenic differentiation of bone marrow MSCs (BMSCs) is important for improving osteoporosis. The aim of this study was to explore the role and molecular mechanism of miR-210 in the balance of osteogenic/adipogenic differentiation of BMSCs in postmenopausal osteoporosis.

METHODS

Postmenopausal osteoporosis rat models were constructed by ovariectomy (OVX). BMSCs were isolated from the femur in rats of Sham and OVX groups. MiR-210 was overexpressed and suppressed by miR-210 mimics and inhibitor, respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the relative mRNA expression of miR-210, ephrin type-A receptor 2 (EPHA2), alkaline phosphatase (ALP), osterix (OSX), osteocalcin (Bglap), Runt-related transcription factor 2 (Runx2), peroxisome proliferator activated receptor gamma, and fatty acid binding protein 4 (FABP4) in each group of rat femoral tissues or BMSCs. Western blot was applied to detect the protein expression level of EPHA2 in rat femoral tissues and cells. Alizarin red S staining and oil red O staining were performed to assess the osteogenic and adipogenic differentiation of BMSCs, respectively. In addition, the targeting relationship between miR-210 and EPHA2 was verified by a dual luciferase gene reporter assay.

RESULTS

The expression of miR-210 was significantly reduced in femoral tissues and BMSCs of OVX rats, and its low expression was associated with reduced bone formation. The osteogenic differentiation was enhanced in OVX rats treated with miR-210 mimic. Overexpression of miR-210 in transfected BMSCs was also found to significantly promote osteogenic differentiation and even inhibit adipogenic differentiation in BMSCs, while knockdown of miR-210 did the opposite. Further mechanistic studies showed that miR-210 could target and inhibit the expression of EPHA2 in BMSCs, thus promoting osteogenic differentiation and inhibiting adipogenic differentiation of BMSCs.

CONCLUSION

MiR-210 promotes osteogenic differentiation and inhibits adipogenic differentiation of BMSCs by down-regulating EPHA2 expression. As it plays an important role in the osteogenic/adipogenic differentiation of osteoporosis, miR-210 can serve as a potential miRNA biomarker for osteoporosis.

Citric acid-modified pH-sensitive bone-targeted delivery of estrogen for the treatment of postmenopausal osteoporosis

Bone targeted delivery of estrogen offers great promise for the clinical application of estrogen in the treatment of postmenopausal osteoporosis (PMOP). However, the current bone-targeted drug delivery system still has several issues that need to be solved, such as the side effects of bone-targeted modifier molecules and the failure of the delivery system to release rapidly in the bone tissue. It is important to aggressively search for new bone-targeted modifier molecules and bone microenvironment-responsive delivery vehicles. Inspired by the distribution of citric acid (CA) mainly in bone tissue and the acidic bone resorption microenvironment, we constructed a CA-modified diblock copolymer poly(2-ethyl-2-oxazoline)-poly(ε-caprolactone) (CA-PEOz) drug delivery system. In our study, we found that the CA modification significantly increased the bone targeting of this drug delivery system, and the delivery system was able to achieve rapid drug release under bone acidic conditions. The delivery system significantly reduced bone loss in postmenopausal osteoporotic mice with a significant reduction in estrogenic side effects on the uterus. In summary, our study shows that CA can act as an effective bone targeting modifier molecule and provides a new option for bone targeting modifications. Our study also provides a new approach for bone-targeted delivery of estrogen for the treatment of PMOP.

Review on the protective activity of osthole against the pathogenesis of osteoporosis

Osteoporosis (OP), characterized by continuous bone loss and increased fracture risk, has posed a challenge to patients and society. Long-term administration of current pharmacological agents may cause severe side effects. Traditional medicines, acting as alternative agents, show promise in treating OP. Osthole, a natural coumarin derivative separated from Cnidium monnieri (L.) Cusson and Angelica pubescens Maxim. f., exhibits protective effects against the pathological development of OP. Osthole increases osteoblast-related bone formation and decreases osteoclast-related bone resorption, suppressing OP-related fragility fracture. In addition, the metabolites of osthole may exhibit pharmacological effectiveness against OP development. Mechanically, osthole promotes osteogenic differentiation by activating the Wnt/β-catenin and BMP-2/Smad1/5/8 signaling pathways and suppresses RANKL-induced osteoclastogenesis and osteoclast activity. Thus, osthole may become a promising agent to protect against OP development. However, more studies should be performed due to, at least in part, the uncertainty of drug targets. Further pharmacological investigation of osthole in OP treatment might lead to the development of potential drug candidates.

Aortic carboxypeptidase-like protein, a putative myokine, stimulates the differentiation and survival of bone-forming osteoblasts

A new target that stimulates bone formation is needed to overcome limitations of current anti-osteoporotic drugs. Myokines, factors secreted from muscles, may modulate it. In this study, we investigated the role of aortic carboxypeptidase-like protein (ACLP), which is highly expressed in skeletal muscles, on bone formation. MC3T3-E1 cells and/or calvaria osteoblasts were treated with recombinant N-terminal mouse ACLP containing a signal peptide [rmACLP (N)]. The expression and secretion of ACLP were higher in skeletal muscle and differentiated myotube than in other tissues and undifferentiated myoblasts, respectively. rmACLP (N) increased bone formation, ALP activity, and phosphorylated p38 mitogen-activated protein (MAP) kinase in osteoblasts; reversal was achieved by pre-treatment with a TGF-β receptor inhibitor. Under H2 O2 treatment, rmACLP (N) increased osteoblast survival, phosphorylated p38 MAP kinase, and the nuclear translocation of FoxO3a in osteoblasts. H2 O2 treatment caused rmACLP (N) to suppress its apoptotic, oxidative, and caspase-9 activities. rmACLP (N)-stimulated osteoblast survival was reversed by pre-treatment with a p38 inhibitor, a TGF-β-receptor II blocking antibody, and a FoxO3a shRNA. Conditioned media (CM) from muscle cells stimulated osteoblast survival under H2 O2 treatment, in contrast to CM from ACLP knockdown muscle cells. rmACLP (N) increased the expressions of FoxO3a target anti-oxidant genes such as Sod2, Trx2, and Prx5. In conclusion, ACLP stimulated the differentiation and survival of osteoblasts. This led to the stimulation of bone formation by the activation of p38 MAP kinase and/or FoxO3a via TGF-β receptors. These findings suggest a novel role for ACLP in bone metabolism as a putative myokine.

Genus Equisetum L: Taxonomy, toxicology, phytochemistry and pharmacology

INTRODUCTION

The genus Equisetum (Equisetaceae) is cosmopolitan in distribution, with 41 recognized species. Several species of Equisetum are widely used in treating genitourinary and related diseases, inflammatory and rheumatic problems, hypertension, and wound healing in traditional medicine practices worldwide. This review intends to present information on the traditional uses, phytochemical components, pharmacological activities, and toxicity of Equisetum spp. and to analyze the new insights for further study.

METHODS

Relevant literature has been scanned and collected via various electronic repositories, including PubMed, Science Direct, Google Scholar, Springer Connect, and Science Online, from 1960 to 2022.

RESULTS

Sixteen Equisetum spp. were documented as widely used in traditional medicine practices by different ethnic groups throughout the world. A total of 229 chemical compounds were identified from Equisetum spp. with the major group of constituents being flavonol glycosides and flavonoids. The crude extracts and phytochemicals of Equisetum spp. exhibited significant antioxidant, antimicrobial, anti-inflammatory, antiulcerogenic, antidiabetic, hepatoprotective, and diuretic properties. A wide range of studies have also demonstrated the safety of Equisetum spp.

CONCLUSION

The reported pharmacological properties of Equisetum spp. support its use in traditional medicine, though there are gaps in understanding the traditional usage of these plants for clinical experiments. The documented information revealed that the genus is not only a great herbal remedy but also has several bioactives with the potential to be discovered as novel drugs. Detailed scientific investigation is still needed to fully understand the efficacy of this genus; hence, very few Equisetum spp. were studied in detail for phytochemical and pharmacological investigation. Moreover, its bioactives, structure-activity connection, in vivo activity, and associated mechanism of action ought to be explored further.

Bioactivity, Molecular Mechanism, and Targeted Delivery of Flavonoids for Bone Loss

Skeletal disabilities are a prominent burden on the present population with an increasing life span. Advances in osteopathy have provided various medical support for bone-related diseases, including pharmacological and prosthesis interventions. However, therapeutics and post-surgery complications are often reported due to side effects associated with modern-day therapies. Thus, therapies utilizing natural means with fewer toxic or other side effects are the key to acceptable interventions. Flavonoids constitute a class of bioactive compounds found in dietary supplements, and their pharmacological attributes have been well appreciated. Recently, flavonoids' role is gaining renowned interest for its effect on bone remodeling. A wide range of flavonoids has been found to play a pivotal role in the major bone signaling pathways, such as wingless-related integration site (Wnt)/β-catenin, bone morphogenetic protein (BMP)/transforming growth factor (TGF)-β, mitogen-activated protein kinase (MAPK), etc. However, the reduced bioavailability and the absorption of flavonoids are the major limitations inhibiting their use against bone-related complications. Recent utilization of nanotechnological approaches and other delivery methods (biomaterial scaffolds, micelles) to target and control release can enhance the absorption and bioavailability of flavonoids. Thus, we have tried to recapitulate the understanding of the role of flavonoids in regulating signaling mechanisms affecting bone remodeling and various delivery methods utilized to enhance their therapeutical potential in treating bone loss.

Inferring Bacterial Community Interactions and Functionalities Associated with Osteopenia and Osteoporosis in Taiwanese Postmenopausal Women

Growing evidence suggests that the gut microbiota and their metabolites are associated with bone homeostasis and fragility. However, this association is limited to microbial taxonomic differences. This study aimed to explore whether gut bacterial community associations, composition, and functions are associated with osteopenia and osteoporosis. We compared the gut bacterial community composition and interactions of healthy postmenopausal women with normal bone density (n = 8) with those of postmenopausal women with osteopenia (n = 18) and osteoporosis (n = 21) through 16S rRNA sequencing coupled with network biology and statistical analyses. The results of this study showed reduced alpha diversity in patients with osteoporosis, followed by that in patients with osteopenia, then in healthy controls. Taxonomic analysis revealed that significantly enriched bacterial genera with higher abundance was observed in patients with osteoporosis and osteopenia than in healthy subjects. Additionally, a co-occurrence network revealed that, compared to healthy controls, bacterial interactions were higher in patients with osteoporosis, followed by those with osteopenia. Further, NetShift analysis showed that a higher number of bacteria drove changes in the microbial community structure of patients with osteoporosis than osteopenia. Correlation analysis revealed that most of these driver bacteria had a significant positive relationship with several significant metabolic pathways. Further, ordination analysis revealed that height and T-score were the primary variables influencing the gut microbial community structure. Taken together, this study evaluated that microbial community interaction is more important than the taxonomic differences in knowing the critical role of gut microbiota in postmenopausal women associated with osteopenia and osteoporosis. Additionally, the significantly enriched bacteria and functional pathways might be potential biomarkers for the prognosis and treatment of postmenopausal women with osteopenia and osteoporosis.

Gut microbiota and fecal metabolic signatures in rat models of disuse-induced osteoporosis

Background

Assessing the correlation between gut microbiota (GM) and bone homeostasis has increasingly attracted research interest. Meanwhile, GM dysbiosis has been found to be associated with abnormal bone metabolism. However, the function of GM in disuse-induced osteoporosis (DIO) remains poorly understood. In our research, we evaluated the characteristics of GM and fecal metabolomics to explore their potential correlations with DIO pathogenesis.

Methods

DIO rat models and controls (CON) underwent micro-CT, histological analyses, and three-point bending tests; subsequently, bone microstructures and strength were observed. ELISAs were applied for the measurement of the biochemical markers of bone turnover while GM abundance was observed using 16S rDNA sequencing. Metabolomic analyses were used to analyze alterations fecal metabolites. The potential correlations between GM, metabolites, and bone loss were then assessed.

Results

In the DIO group, the abundance of GM was significantly altered compared to that in the CON group. Moreover, DIO significantly altered fecal metabolites. More specifically, an abnormally active pathway associated with bile acid metabolism, as well as differential bacterial genera related to bone/tissue volume (BV/TV), were identified. Lithocholic acid, which is the main secondary bile acid produced by intestinal bacteria, was then found to have a relationship with multiple differential bacterial genera. Alterations in the intestinal flora and metabolites in feces, therefore, may be responsible for DIO-induced bone loss.

Conclusions

The results indicated that changes in the abundance of GM abundance and fecal metabolites were correlated with DIO-induced bone loss, which might provide new insights into the DIO pathogenesis. The detailed regulatory role of GM and metabolites in DIO-induced bone loss needs to be explored further.

Comparing the effectiveness of type of the traditional Chinese exercises, frequency, intensity, time in osteoporosis: a protocol for systematic evaluation and network meta-analysis of randomised controlled trials

INTRODUCTION

As populations age, osteoporosis has become a hot topic of global public concern. The beneficial effects of traditional Chinese exercises on the musculoskeletal system have been demonstrated. However, previous research findings on osteoporosis are inconsistent, and it is unclear which type of exercise and its frequency and duration have the best effect on osteoporosis. This study aims to investigate the most appropriate exercise modality for people with osteoporosis through systematic evaluation and network meta-analysis to guide clinical practice.

METHODS AND ANALYSIS

The Cochrane Library, Web of Science, MEDLINE, Embase, China Biomedical Literature, China Knowledge Network, China Science and Technology Journal and Wanfang databases will be searched until January 2022. The language of the articles should be English or Chinese. All clinical randomised controlled trials on the effect of traditional Chinese exercises on osteoporosis will be included. We will use RevMan, Stata and GeMTC software to complete our network meta-analysis. We will perform risk of bias assessment, subgroup analysis and sensitivity analysis to correct the results. Finally, we will use the Grading of Recommendations Assessment, Development and Evaluation guideline development tool and Confidence in Network Meta-Analysis (CINeMA, a new method for assessing CINeMA results) approach to evaluate the reliability of our final results.

ETHICS AND DISSEMINATION

All data for this study will be obtained from published studies, so no ethical review will be needed. We will publish the results of the study in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022323622.

Epigallocatechin-3-gallate inhibits osteoclastic differentiation by modulating mitophagy and mitochondrial functions

A natural plant product, epigallocatechin-3-gallate (EGCG), was evaluated for its effectiveness in the regulation of osteoclastogenesis. We found that EGCG inhibited the osteoclast (OC) differentiation in vitro, and in primary bone marrow cells in a dose-dependent manner. Quantitative RT-PCR studies showed that the EGCG reduced the expression of OC differentiation markers. DCFDA, MitoSOX, and JC-1 staining revealed that the EGCG attenuated the reactive oxygen species (ROS), and mitochondrial membrane potential; and flux analysis corroborated the effect of EGCG. We further found that the EGCG inhibited mRNA and protein expressions of mitophagy-related molecules. We confirmed that the OC differentiation was inhibited by EGCG by modulating mitophagy through AKT and p38MAPK pathways. Furthermore, in silico analysis revealed that the binding of RANK and RANKL was blocked by EGCG. Overall, we defined the mechanisms of osteoclastogenesis during arthritis for developing a new therapy using a natural compound besides the existing therapeutics.

Effect of Taraxaci Herba on Bone Loss in an OVX-Induced Model through the Regulation of Osteoclast Differentiation

Bone is a dynamic tissue that maintains homeostasis with a balance of osteoclasts for bone resorption and osteoblasts for bone formation. Women are deficient in estrogen after menopause, which promotes bone resorption due to excessive activity of osteoclasts, leading to osteoporosis. TH (also known as dandelion) is native to warm regions and has traditionally been used to treat gynecological diseases and inflammation. Menopause is a major cause of osteoporosis as it causes abnormal activity of osteoclasts, and various studies have shown that anti-inflammatory drugs have the potential to treat osteoporosis. We analyzed the effect of TH on osteoclast differentiation and the relevant mechanisms using RANKL. After administration of TH in a menopause-like rat model in which ovariectomy of the was rats carried out, changes in bone microstructure were analyzed via micro-CT, and the antiosteoporosis effect of TH was verified by a histological analysis. In addition, the pharmacological effects of TH in an animal model of osteoporosis were compared and analyzed with osteoporosis medications (17β-estradiol (E₂) and alendronate (ALN)). TH significantly inhibited the initial osteoclast differentiation via the NFATc1/c-Fos mechanism. In addition, bone density in the femur of osteoporotic rats was increased, and the expression of osteoclast-related factors in the serum and tissues was controlled. The results of this study provide objective evidence of the inhibitory effect of TH on osteoclastogenesis and OVX-induced bone loss.

Anti-Osteoclast Effect of Exportin-1 Inhibitor Eltanexor on Osteoporosis Depends on Nuclear Accumulation of IκBα–NF-κB p65 Complex

Osteoporosis affects around 200 million people globally, with menopausal women accounting for the bulk of cases. In the occurrence and development of osteoporosis, a key role is played by osteoclasts. Excessive osteoclast-mediated bone resorption activity reduces bone mass and increases bone fragility, resulting in osteoporosis. Thus, considerable demand exists for designing effective osteoporosis treatments based on targeting osteoclasts. Eltanexor (Elt; KPT-8602) is a selective nuclear-export inhibitor that covalently binds to and blocks the function of the nuclear-export protein exportin-1 (XPO1), which controls the nucleus-to-cytoplasm transfer of certain critical proteins related to growth regulation and tumor suppression, such as p53, IκBα [nuclear factor-κB (NF-κB) inhibitor α] and FOXO1; among these proteins, IκBα, a critical component of the NF-κB signaling pathway that primarily governs NF-κB activation and transcription. How Elt treatment affects osteoclasts remains poorly elucidated. Elt inhibited the growth and activity of RANKL-induced osteoclasts in vitro in a dose-dependent manner, and Elt exerted no cell-killing effect within the effective inhibitory concentration. Mechanistically, Elt was found to trap IκBα in the nucleus and thus protect IκBα from proteasome degradation, which resulted in the blocking of the translocation of IκBα and NF-κB p65 and the consequent inhibition of NF-κB activity. The suppression of NF-κB activity, in turn, inhibited the activity of two transcription factors (NFATc1 and c-Fos) essential for osteoclast formation and led to the downregulation of genes and proteins related to bone resorption. Our study thus provides a newly identified mechanism for targeting in the treatment of osteoporosis.

Comparison of Pharmacokinetic Profiles of 14 Major Bioactive Components in Normal and Arthritic Model Rats after Oral Administration of Angelicae pubescentis Radix by UPLC-MS/MS

An ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to simultaneously determine 14 compounds of Angelicae pubescentis Radix (APR) in normal and arthritis rat plasma in which chloramphenicol and daidzein were used as the internal standards. After protein precipitation with acetonitrile, separation was carried out on a Thermo Hypersil GOLD C₁₈ column using gradient elution with 0.1% formic acid aqueous and acetonitrile consisting as the mobile phase at a flowing rate of 0.3 mL/min. A Thermo TSQ QUANTIS triple quadrupole mass spectrometer was used to detect 14 compounds in positive/negative ion exchange mode and this study was the first to investigate the pharmacokinetic changes of the active compounds in rats under the pathological state of arthritis. The method was verified and the results showed that the intra- and interday precision, accuracy, matrix effect, and extraction recovery were all acceptable, and the analytes were stable under different storage conditions. In addition, the pharmacokinetic behaviors of the 14 compounds were significantly different in model rats compared with normal rats. This indicated that the pharmacokinetic behavior of drugs will vary with the pathological state of the body, which suggested that individualized and reasonable drug administration plans should be formulated for different pathological states in clinical practice. This study provided a scientific basis and data support for better understanding the pharmacodynamic substance basis and clinical application of APR against arthritis.

A Predictive Model for Abnormal Bone Density in Male Underground Coal Mine Workers

The dark and humid environment of underground coal mines had a detrimental effect on workers’ skeletal health. Optimal risk prediction models can protect the skeletal health of coal miners by identifying those at risk of abnormal bone density as early as possible. A total of 3695 male underground workers who attended occupational health physical examination in a coal mine in Hebei, China, from July to August 2018 were included in this study. The predictor variables were identified through single-factor analysis and literature review. Three prediction models, Logistic Regression, CNN and XG Boost, were developed to evaluate the prediction performance. The training set results showed that the sensitivity of Logistic Regression, XG Boost and CNN models was 74.687, 82.058, 70.620, the specificity was 80.986, 89.448, 91.866, the F1 scores was 0.618, 0.919, 0.740, the Brier scores was 0.153, 0.040, 0.156, and the Calibration-in-the-large was 0.104, 0.020, 0.076, respectively, XG Boost outperformed the other two models. Similar results were obtained for the test set and validation set. A two-by-two comparison of the area under the ROC curve (AUC) of the three models showed that the XG Boost model had the best prediction performance. The XG Boost model had a high application value and outperformed the CNN and Logistic regression models in prediction.

Effect of Anti-Osteoporotic Treatments on Circulating and Bone MicroRNA Patterns in Osteopenic ZDF Rats

Bone fragility is an adverse outcome of type 2 diabetes mellitus (T2DM). The underlying molecular mechanisms have, however, remained largely unknown. MicroRNAs (miRNAs) are short non-coding RNAs that control gene expression in health and disease states. The aim of this study was to investigate the genome-wide regulation of miRNAs in T2DM bone disease by analyzing serum and bone tissue samples from a well-established rat model of T2DM, the Zucker Diabetic Fatty (ZDF) model. We performed small RNA-sequencing analysis to detect dysregulated miRNAs in the serum and ulna bone of the ZDF model under placebo and also under anti-sclerostin, PTH, and insulin treatments. The dysregulated circulating miRNAs were investigated for their cell-type enrichment to identify putative donor cells and were used to construct gene target networks. Our results show that unique sets of miRNAs are dysregulated in the serum (n = 12, FDR < 0.2) and bone tissue (n = 34, FDR < 0.2) of ZDF rats. Insulin treatment was found to induce a strong dysregulation of circulating miRNAs which are mainly involved in metabolism, thereby restoring seven circulating miRNAs in the ZDF model to normal levels. The effects of anti-sclerostin treatment on serum miRNA levels were weaker, but affected miRNAs were shown to be enriched in bone tissue. PTH treatment did not produce any effect on circulating or bone miRNAs in the ZDF rats. Altogether, this study provides the first comprehensive insights into the dysregulation of bone and serum miRNAs in the context of T2DM and the effect of insulin, PTH, and anti-sclerostin treatments on circulating miRNAs.

Dietary Collagen Hydrolysates Retard Estrogen Deficiency-Induced Bone Loss through Blocking Osteoclastic Activation and Enhancing Osteoblastic Matrix Mineralization

Osteoporosis manifest in postmenopausal women is an osteolytic disease characterized by bone loss, leading to increased susceptibility to bone fractures and frailty. The use of complementary therapies to alleviate postmenopausal osteoporosis is fairly widespread among women. The current study examined that Pangasius hypophthalmus fish skin collagen hydrolysates (fsCH) inhibited ovariectomy (OVX)-induced bone loss by conducting inter-comparative experiments for anti-osteoporotic activity among 206–618 mg/kg fsCH, 2 mg/kg isoflavone, 15 mg/kg glycine–proline–hydroxyproline (GPH) tripeptide, and calcium lactate. Surgical estrogen loss of mice for 8 weeks reduced serum 17β-estradiol levels with uterus atrophy, which was ameliorated by orally administering fsCH or isoflavone to mice. Similar to isoflavone, fsCH containing GPH-enhanced bone mineral density reduced levels of cathepsin K and proton-handling proteins, and elevated collagen 1 level in OVX bones. The treatment with fsCH and isoflavone enhanced the serum levels of collagen synthesis-related procollagen type 1 carboxy/amino-terminal propeptides reduced by OVX, whereas serum levels of osteocalcin and alkaline phosphatase, as well as collagen breakdown-related carboxy/amino-terminal telopeptides of type 1 collagen were reduced in OVX mice treated with fsCH, isoflavone, and calcium lactate. The trabecular bones were newly formed in OVX bones treated with isoflavone and fsCH, but not with calcium lactate. However, a low-dose combination of fsCH and calcium lactate had a beneficial synergy effect on postmenopausal osteoporosis. Furthermore, similar to isoflavone, 15–70 μg/mL fsCH, with its constituents of GPH and dipeptides of glycine–proline and proline–hydroxyproline, enhanced osteogenesis through stimulating differentiation, matrix mineralization, and calcium deposition of MC3T3-E1 osteoblasts. Accordingly, the presence of fsCH may encumber estrogen deficiency-induced bone loss through enhancing osteoclastogenic differentiation and matrix collagen synthesis. Therefore, fsCH may be a natural compound retarding postmenopausal osteoporosis and pathological osteoresorptive disorders.

Impact of the Malnutrition on Mortality in Patients With Osteoporosis: A Cohort Study From NHANES 2005-2010

Background

Osteoporosis is the most common metabolic bone disease. Recent studies have shown that malnutrition can promote the development of osteoporosis. However, the incidence of malnutrition in patients with osteoporosis and the relationship between malnutrition and all-cause mortality has not been adequately studied. Therefore, our study investigated the relationship between malnutrition and all-cause mortality in patients with osteoporosis.

Methods

We analyzed data on 7,700 adults ≥20 years of age during National Health and Nutrition Examination Survey (NHANES) 2005-2010. Each patient was assigned to one of three groups: normal nutritional status, mild malnutrition, and moderate to severe malnutrition. Survival curves and univariate and multivariable cox regressions based on the NHANES recommended weights were used to assess the association between malnutrition status and mortality. Moreover, cox proportional hazards regression analyses were performed on the matched pairs.

Results

Overall, 7,700 eligible individuals with osteoporosis were included in the final analysis, and the mean age was 52.0 ± 0.4 years. From the Kaplan–Meier curves for long-term all-cause mortality of malnutrition, worsening malnutrition status was associated with higher incidence of all-cause mortality. In the fully adjusted models, the adjusted hazard ratio (aHR) was 1.54 [95% confidence interval (CI), 1.02–2.31, p = 0.039] at mild malnutrition status and 2.70 (95%CI, 1.95–3.74, p < 0.001) at moderate to severe malnutrition status. The cox model after matching indicated that malnutrition was still a high mortality risk than no malnutrition (aHR = 2.23, 95% CI, 1.66–3.01, p < 0.001).

Conclusions

Poor malnutrition status, common in osteoporotic patients, is strongly associated with a risk for all-cause mortality comparable to that seen with normal nutritional status. These findings highlight the importance of risk stratification for nutritional status in osteoporotic patients and the implementation of strategies that is now available to help prevent malnutrition in these patients.

Niloticin inhibits osteoclastogenesis by blocking RANKL-RANK interaction and suppressing the AKT, MAPK, and NF-κB signaling pathways

Dysregulation of osteoclasts or excessive osteoclastogenesis significantly -contributes to the occurrence and development of osteolytic diseases, including osteoporosis, inflammatory bone erosion, and tumor-induced osteolysis. The protein-protein interaction between the receptor activator of nuclear factor (NF)-κB (RANK) and its ligand (RANKL) mediates the differentiation and activation of osteoclasts, making it a key therapeutic target for osteoclastogenesis inhibition. However, very few natural compounds exerting anti-osteoclastogenesis activity by inhibiting the RANKL-RANK interaction have been found. Niloticin is a natural tetracyclic triterpenoid compound with anti-viral, antioxidative, and mosquitocidal activities. However, its role in osteoclastogenesis remains unknown. The present study found that niloticin directly binds to RANK with an equilibrium dissociation constant of 5.8 μM, blocking RANKL-RANK interaction, thereby inhibiting RANKL-induced AKT, MAPK (p38, JNK, and ERK1/2), and NF-κB (IKKα/β, IκBα, and p65) pathways activation, and reducing the expression of key osteoclast differentiation-related regulatory factors (NFATc1, c-Fos, TRAP, c-Src, β3-Integrin, and cathepsin K) in osteoclast precursors, ultimately negatively regulating osteoclastogenesis. These findings suggest that niloticin could serve as a novel osteoclastogenesis inhibitor and might have beneficial effects on bone health.

Advances in pathogenesis and therapeutic strategies for osteoporosis

Osteoporosis, is the most common bone disorder worldwide characterized by low bone mineral density, leaving affected bones vulnerable to fracture. Bone homeostasis depends on the precise balance between bone resorption by osteoclasts and bone matrix formation by mesenchymal lineage osteoblasts, and involves a series of complex and highly regulated steps. Bone homeostasis will be disrupted when the speed of bone resorption is faster than bone formation. Based on various regulatory mechanisms of bone homeostasis, a series of drugs targeting osteoporosis have emerged in clinical practice, including bisphosphonates, selective estrogen receptor modulators, calcitonin, molecular-targeted drugs and so on. However, many drugs have major adverse effects or are unsuitable for long-term use. Therefore, it is very urgent to find more effective therapeutic drugs based on the new pathogenesis of osteoporosis. In this review, we summarize novel mechanisms involved in the pathological process of osteoporosis, including the roles of gut microbiome, autophagy, iron balance and cellular senescence. Based on the above pathological mechanism, we found promising drugs for osteoporosis treatment, such as: probiotics, alpha-ketoglutarate, senolytics and hydrogen sulfide. This new finding may provide an important basis for elucidating the complex pathological mechanisms of osteoporosis and provide promising drugs for clinical osteoporosis treatment.

The Role of Macronutrients, Micronutrients and Flavonoid Polyphenols in the Prevention and Treatment of Osteoporosis

Osteoporosis is considered an age-related disorder of the skeletal system, characterized primarily by decreased bone mineral density (BMD), microstructural quality and an elevated risk of fragility fractures. This silent disease is increasingly becoming a global epidemic due to an aging population and longer life expectancy. It is known that nutrition and physical activity play an important role in skeletal health, both in achieving the highest BMD and in maintaining bone health. In this review, the role of macronutrients (proteins, lipids, carbohydrates), micronutrients (minerals—calcium, phosphorus, magnesium, as well as vitamins—D, C, K) and flavonoid polyphenols (quercetin, rutin, luteolin, kaempferol, naringin) which appear to be essential for the prevention and treatment of osteoporosis, are characterized. Moreover, the importance of various naturally available nutrients, whether in the diet or in food supplements, is emphasized. In addition to pharmacotherapy, the basis of osteoporosis prevention is a healthy diet rich mainly in fruits, vegetables, seafood and fish oil supplements, specific dairy products, containing a sufficient amount of all aforementioned nutritional substances along with regular physical activity. The effect of diet alone in this context may depend on an individual’s genotype, gene-diet interactions or the composition and function of the gut microbiota.

The "Three in One" Bone Repair Strategy for Osteoporotic Fractures

In aging society, osteoporotic fractures have become one major social problem threatening the health of the elderly population in China. Compared with conventional fractures, low bone mass, bone defect and retarded healing issues of osteoporotic fractures lead to great difficulties in treatment and rehabilitation. Addressing major concerns in clinical settings, we proposed the "three in one" bone repair strategy focusing on anti-osteoporosis therapies, appropriate bone grafting and fracture healing accelerating. We summarize misconceptions and repair strategies for osteoporotic fracture management, expecting improvement of prognosis and clinical outcomes for osteoporotic fractures, to further improve therapeutic effect and living quality of patients.

The roles of circRNA-miRNA-mRNA networks in the development and treatment of osteoporosis

Osteoporosis is a systemic metabolic disease, mainly characterized by reduced bone mineral density and destruction of bone tissue microstructure. However, the molecular mechanisms of osteoporosis need further investigation and exploration. Increasing studies have reported that circular RNAs (circRNAs), a novel type of RNA molecule, play crucial roles in various physiological and pathological processes and bone-related diseases. Based on an in-depth understanding of their roles in bone development, we summarized the multiple regulatory roles and underlying mechanisms of circRNA-miRNA-mRNA networks in the treatment of osteoporosis, associated with bone marrow mesenchymal stem cells (BMSCs), osteoblasts, and osteoclasts. Deeper insights into the vital roles of circRNA-miRNA-mRNA networks can provide new directions and insights for developing novel diagnostic biomarkers and therapeutic targets in the treatment of osteoporosis.