An overview on the treatment of postmenopausal osteoporosis

Osteoclast-derived exosomes influence osteoblast differentiation in osteoporosis progression via the lncRNA AW011738/ miR-24-2-5p/ TREM1 axis

AIMS

To investigate the molecular mechanism of osteoclast-derived exosomes in osteoporosis.

MAIN METHODS

RANKL induced osteoclast model was screened for significantly differentially expressed lncRNAs and mRNAs by whole RNA sequencing. Exosomes were characterized using electron microscopy, western blotting and nanosight. Overexpression or knockdown of AW011738 was performed to explore its function. The degree of osteoporosis in an osteoporosis model was assessed by mirco-CT. The osteoclast model, osteoblast differentiation ability and the molecular mechanism of lncRNA AW011738/miR-24-2-5p/TREM1 axis in osteoporosis were assessed by dual luciferase reporter gene assay, Western blotting (WB), immunofluorescence and ALP staining. Bioinformatics was used to predict interactions of key osteoporosis-related genes with miRNAs, transcription factors, and potential drugs after upregulation of AW011738. To predict the protein-protein interaction (PPI) network associated with key genes, GO and KEGG analyses were performed on the key genes. The ssGSVA was used to predict changes in the immune microenvironment.

KEY FINDINGS

Osteoclast-derived exosomes containing lncRNA AW011738 decreased the osteogenesis-related markers and accelerated bone loss in OVX mice. Osteoclast (si-AW011738)-derived exosomes showed a significant increase in biomarkers of osteoblast differentiation in vitro compared to the si-NC group. As analyzed by mirco-CT, tail vein injected si-AW011738 OVX mice were less osteoporotic than the control group. AW011738 inhibited osteoblast differentiation by regulating TREM1 expression through microRNA. Meanwhile, overexpression of miR-24-2-5p inhibited TREM1 expression to promote osteoblast differentiation.

SIGNIFICANCE

Osteoclast-derived exosomes containing lncRNA AW011738 inhibit osteogenesis in MC3T3-E1 cells through the lncRNA AW011738/miR-24-2-5p/TREM1 axis and exacerbate osteoporosis in OVX mice.

Association between hepatic steatosis and fibrosis and arthritis among US adults: A population-based study

BACKGROUND

Lipid metabolism factors may play a role in the development of arthritis and hepatic steatosis and fibrosis. The aim of this study was to explore the potential association between arthritis and hepatic steatosis and liver fibrosis.

MATERIALS AND METHODS

The nationally representative sample from the National Health and Nutrition Examination Survey was analyzed, with data on arthritis diagnosis, subtype, and liver status obtained. Liver status was assessed using transient elastography. Hepatic steatosis was defined as a Controlled Attenuation Parameter (CAP) score ≥263 dB/m, and liver fibrosis status was defined as F0‒F4. Logistic regression models and subgroup analyses stratified by sex were used to evaluate the associations. Smooth curve fitting was used to describe the associations.

RESULTS

The present study of 6,840 adults aged 20 years or older found a significant positive correlation between arthritis and CAP in multivariate logistic regression analysis (β = 0.003, 95 % CI 0.001 to 0.0041, p < 0.001). Participants with arthritis had a higher risk of hepatic steatosis (OR = 1.248, 95 % CI 1.036 to 1.504, p = 0.020), particularly those with osteoarthritis or degenerative arthritis, but not rheumatoid arthritis (p = 0.847). The positive correlation was maintained in females (β = 0.004, 95 % CI 0.002 to 0.006, p < 0.001), but not in males. There was no significant relationship between arthritis and liver fibrosis (p = 0.508).

CONCLUSION

This study indicates that there is a positive correlation between arthritis and hepatic steatosis, particularly in females. Nonetheless, there is no significant relationship between arthritis and the risk of liver fibrosis.

Consequences of Aging on Bone

With the aging of the global population, the incidence of musculoskeletal diseases has been increasing, seriously affecting people's health. As people age, the microenvironment within skeleton favors bone resorption and inhibits bone formation, accompanied by bone marrow fat accumulation and multiple cellular senescence. Specifically, skeletal stem/stromal cells (SSCs) during aging tend to undergo adipogenesis rather than osteogenesis. Meanwhile, osteoblasts, as well as osteocytes, showed increased apoptosis, decreased quantity, and multiple functional limitations including impaired mechanical sensing, intercellular modulation, and exosome secretion. Also, the bone resorption function of macrophage-lineage cells (including osteoclasts and preosteoclasts) was significantly enhanced, as well as impaired vascularization and innervation. In this study, we systematically reviewed the effect of aging on bone and the within microenvironment (including skeletal cells as well as their intracellular structure variations, vascular structures, innervation, marrow fat distribution, and lymphatic system) caused by aging, and mechanisms of osteoimmune regulation of the bone environment in the aging state, and the causal relationship with multiple musculoskeletal diseases in addition with their potential therapeutic strategy.

Exosome-targeted delivery of METTL14 regulates NFATc1 m6A methylation levels to correct osteoclast-induced bone resorption

Osteoporosis has a profound influence on public health. First-line bisphosphonates often cause osteonecrosis of the jaw meanwhile inhibiting osteoclasts. Therefore, it is important to develop effective treatments. The results of this study showed that the increased level of NFATc1 m6A methylation caused by zoledronic acid (ZOL), with 4249A as the functional site, is highly correlated with the decreased bone resorption of osteoclasts. Upstream, METTL14 regulates osteoclast bone absorption through the methylation functional site of NFATc1. Downstream, YTHDF1 and YTHDF2 show antagonistic effects on the post-transcriptional regulation of NFATc1 after the m6A methylation level is elevated by METTL14. In this study, meRIP-Seq, luciferase reporter assays, meRIP and other methods were used to elucidate the NFATc1 regulatory mechanism of osteoclasts from the perspective of RNA methylation. In addition, EphA2 overexpression on exosomes is an effective biological method for targeted delivery of METTL14 into osteoclasts. Importantly, this study shows that METTL14 released by exosomes can increase the m6A methylation level of NFATc1 to inhibit osteoclasts, help postmenopausal osteoporosis patients preserve bone mass, and avoid triggering osteonecrosis of the jaw, thus becoming a new bioactive molecule for the treatment of osteoporosis.

Physiopathology of Osteoporosis: Nursing Involvement and Management

Osteoporosis is a major public health problem today. We are facing an aging society where the average life expectancy continues to increase. Osteoporosis affects more than 30% of postmenopausal women due to hormonal changes that occur during this time. Postmenopausal osteoporosis is therefore of particular concern. The aim of this review is to identify the etiology, pathophysiology, diagnosis and treatment of this disease and lay the foundation for the role nurses should play in preventing postmenopausal osteoporosis. Several risk factors are associated with osteoporosis. In addition to age and sex, genetics, ethnicity, diet, or the presence of other disorders determine the development of this disease. The key factors include exercise, a balanced diet, and high levels of vitamin D. This is primarily from a solar source, and infancy is the time when future bone formation is greatest. There are now medications that can complement these preventive measures. The work of nursing staff is not only prevention, but also early detection and early treatment. In addition, imparting information and knowledge about the disease to the population is key to preventing an osteoporosis epidemic. In this study, a detailed description is provided of the biological and physiological disease, the preventive measures currently being researched, the information currently available to the population, and how health professionals address osteoporosis from a preventive perspective.

Cirsium Setidens Water Extracts Containing Linarin Block Estrogen Deprivation-Induced Bone Loss in Mice

Osteoporosis is evident in postmenopausal women and is an osteolytic disease characterized by bone loss that further increases the susceptibility to bone fractures and frailty. The use of complementary therapies to alleviate postmenopausal osteoporosis is fairly widespread among women. Edible Cirsium setidens contains various polyphenols of linarin, pectolinarin, and apigenin with antioxidant and hepatoprotective effects. This study aimed to determine whether Cirsium setidens water extracts (CSEs), the component linarin, and its aglycone acacetin blocked ovariectomy (OVX)-induced bone loss. This study employed OVX C57BL/6 female mice as a model for postmenopausal osteoporosis. CSEs, acacetin, or linarin was orally administrated to OVX mice at a dose of 20 mg/kg for 8 weeks. Surgical estrogen loss in mice for 8 weeks reduced bone mineral density (BMD) of mouse femur and serum 17β-estradiol level and enhanced the serum receptor activator of NF-κB ligand/osteoprotegerin ratio with uterine atrophy. CSEs and linarin reversed such adverse effects and enhanced femoral BMD in OVX mice. Oral administration of CSEs and linarin attenuated tartrate-resistant acid phosphate activity and the induction of αvβ3 integrins and proton suppliers in resorption lacunae in femoral bone tissue of OVX mice. In addition, CSEs and linarin curtailed the bone levels of cathepsin K and matrix metalloproteinase-9 responsible for osteoclastic bone resorption. On the other hand, CSEs and linarin enhanced the formation of trabecular bones in estrogen-deficient femur with increased induction of osteocalcin and osteopontin. Further, treatment with CSEs and linarin enhanced the collagen formation-responsive propeptide levels in the circulation along with the increase in the tissue non-specific alkaline phosphatase level in bone exposed to OVX. Supplementing CSEs, acacetin, or linarin to OVX mice elevated the formation of collagen fibers in OVX trabecular bone, evidenced using Picrosirius red staining. Accordingly, CSEs and linarin were effective in retarding osteoclastic bone resorption and promoting osteoblastic bone matrix mineralization under OVX conditions. Therefore, linarin, which is abundant in CSEs, may be a natural compound for targeting postmenopausal osteoporosis and pathological osteoresorptive disorders.

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

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

4D label-free quantitative proteomics analysis to screen potential drug targets of Jiangu Granules treatment for postmenopausal osteoporotic rats

Background: Postmenopausal osteoporosis (PMOP) is a disease with a high prevalence in postmenopausal women and is characterized by an imbalance in bone metabolism, reduced bone mass, and increased risk of fracture due to estrogen deficiency. Jiangu granules (JG) is a compound prescription used in traditional Chinese medicine to treat PMOP. However, its definitive mechanism in PMOP is unclear. This study used a 4D label-free quantitative proteomics method to explore the potential therapeutic mechanism of JG in an ovariectomy (OVX) rats' model. Materials and methods: A rat model of PMOP was established by removing the ovaries bilaterally. Nine 3-month-old specific-pathogen-free female SD rats. The nine rats were randomly divided into 3 groups (n = 3 in each group): the sham-operated group (J), the ovariectomy group (NC), and the JG treatment (ZY) group. Proteins extracted from the bone tissue of the lumbar spine (L3, L4) of three groups of rats were analyzed by 4D label-free quantitative proteomics, and proteins differentially expressed after JG treatment and proteins differentially expressed after de-ovulation were intersected to identify proteins associated with the mechanism of PMOP by JG treatment. Result: There were 104 up-regulated and 153 down-regulated differentially expressed proteins (DEPs) in the J group vs. NC group, 107 up-regulated and 113 down-regulated DEPs in the J group vs. ZY group, and 15 up-regulated and 32 down-regulated DEPs in the NC group vs. ZY group. Six potential target proteins for JG regulation of osteoblast differentiation in OVX rats were identified by taking intersections of differential proteins in the J group vs. NC group and NC group vs. ZY group. Conclusion: JG may exert therapeutic effects by modulating the expression levels of target proteins associated with osteoblast differentiation to enhance osteoblast differentiation in OVX rats. These results further uncovered the target proteins and specific mechanisms of JG in treating PMOP, providing an experimental basis for the clinical application of JG in treating PMOP.

Effects of Three Interventions Combining Impact or Walking at Intense Pace Training, with or without Calcium and Vitamin Supplements, to Manage Postmenopausal Women with Osteopenia and Osteoporosis

The purpose was to assess the effects of three interventions on bone mineral density (BMD) to prevent the onset or progression of osteoporosis in postmenopausal women. Specifically, thirty-nine postmenopausal women, diagnosed with osteopenia or osteoporosis, implemented either high-impact training (G1), the same training + calcium and vitamin D intake (G2), or walked at an intense pace + calcium and vitamin D (G3). Baseline change (BC) in BMD was estimated using the femoral neck and lumbar spine T-scores. Participants were classified as having suffered fractures and/or falls before (24-month) and during the 2-year intervention. The participants-aged 61.8 years-were allocated into G1 (n = 9), G2 (n = 16), and G3 (n = 14). The groups evolved similarly over time; however, participants in G2 exhibited the largest T-score improvements with BC over 20%. G1 and G3 maintained BMD levels (BC = -7 to 13.3%; p > 0.05). Falls occurred similarly across the interventions, while the participants in G2 had the lowest percentage of fracture events (p = 0.037). Overall, the findings suggest that regular physical exercise may be effective in maintaining or improving BMD in postmenopausal women presenting with osteopenia or osteoporosis. Due to the limited sample size, the results are preliminary and warrant future randomized trials to validate the findings.

WITHDRAWN: Role of microRNA-19b-3p on osteoporosis after experimental spinal cord injury in rats

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Osteoporosis Drug Treatment Update

The Brazilian population is aging and the prevalence of chronic degenerative diseases, including osteoporosis, is increasing. The diagnosis and treatment of osteoporosis have made significant advances in the last decade. The orthopedist and traumatologist can no longer be detained only in the surgical treatment of osteoporotic fracture. It is extremely important that we know: 1) what risk factors to evaluate, and the Fracture Risk Assesment Tool (FRAX) can be used; 2) which complementary tests should be requested, such as densitometry, radiography of the spine and pelvis, blood and urine tests, and even bone biopsy; 3) which supplements to use, such as calcium and magnesium, vitamins D and K; 4) which medications to prescribe, antiresorptives or trainers, therapeutic windows and adverse events.

Exercise vs Conventional Treatment for Treatment of Primary Osteoporosis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective

Physical exercise has obvious effects on bone loss, pain relief, and improvement of bone metabolism indexes in patients with osteoporosis, but currently lacks sufficient evidence. The aim of this systematic review and meta‐analysis was to synthesize and present the best available evidence on the effectiveness and safety of exercises in the treatment of primary osteoporosis.

Methods

Publications pertaining to the effectiveness of exercise on bone mineral density (BMD), visual analog scores (VAS), and biochemical markers of bone metabolism in primary osteoporosis (POP) from PubMed, Cochrane Library, Embase, VIP, CNKI, and Wanfang Database were retrieved from their inception to April 2020.

Results

A total of 20 studies with 1824 participants were included. The results of the meta‐analysis revealed that exercise therapy for lumbar spine and femoral neck BMD is statistically different from conventional therapy (lumbar spine BMD: SMD = 0.78, 95%CI: 0.46, 1.10, P < 0.00001, I² = 85%; femoral neck BMD (SMD = 0.80, 95%CI: 0.34, 1.27, P = 0.0007, I² = 88%), exercise therapy can significantly increase the lumbar spine BMD of patients with OP, especially in lumbar spine2‐4 BMD (SMD = 0.47; 95%CI: 0.20, 0.75; P = 0.0008; I² = 69%). Compared with conventional treatment, kinesitherapy also has significant differences in alleviating the pain of POP patients (SMD = −1.39, 95%CI: −2.47,−0.31, P = 0.01, I² = 97%). Compared with conventional therapy, kinesitherapy has no significant difference in improving biochemical markers of bone metabolism such as bone glaprotein (BGP) (SMD = 2.59, 95%CI:0.90, 4.28, P = 0.003, I² = 98%), N‐terminal pro peptide of type I procollagen (PINP) (SMD = 0.77, 95%CI: −0.44 to 1.98, P = 0.21, I² = 95%), serum phosphorus (SMD = 0.04, 95%CI: −0.13, 0.22, P = 0.61, I² = 30%), alkaline phosphatase (ALP) (SMD = −0.08, 95%CI: −0.44, 0.27, P = 0.64, I² = 76%), and serum calcium (SMD = 0.12, 95%CI: −0.18, 0.43, P = 0.42, I² = 63%) in POP patients.

Conclusions

Kinesitherapy significantly improved lumbar spine and femoral neck BMD, and relieve the pain of patients in the current low‐quality evidence. Additional high‐quality evidence is required to confirm the effect of exercise therapy on the biochemical markers of bone metabolism in POP patients.

Prevention and treatment of oral adverse effects of antiresorptive medications for osteoporosis - A position paper of the Brazilian Society of Endocrinology and Metabolism (SBEM), Brazilian Society of Stomatology and Oral Pathology (Sobep), and Brazilian Association for Bone Evaluation and Osteometabolism (Abrasso)

Antiresorptive therapy is the main form of prevention of osteoporotic or fragility fractures. Medication-related osteonecrosis of the jaw (MRONJ) is a relatively rare but severe adverse reaction to antiresorptive and antiangiogenic drugs. Physicians and dentists caring for patients taking these drugs and requiring invasive procedures face a difficult decision because of the potential risk of MRONJ. The aim of this study was to discuss the risk factors for the development of MRONJ and prevention of this complication in patients with osteoporosis taking antiresorptive drugs and requiring invasive dental treatment. For this goal, a task force with representatives from three professional associations was appointed to review the pertinent literature and discuss systemic and local risk factors, prevention of MRONJ in patients with osteoporosis, and management of established MRONJ. Although scarce evidence links the use of antiresorptive agents in the context of osteoporosis to the development of MRONJ, these agents are considered a risk factor for this complication. Despite the rare reports of MRONJ in patients with osteoporosis, the severity of symptoms and impact of MRONJ in the patients' quality of life make it imperative for health care professionals to consider this complication when planning invasive dental procedures.

Melatonin inhibits RANKL‑induced osteoclastogenesis through the miR‑882/Rev‑erbα axis in Raw264.7 cells

Melatonin, secreted in a typical diurnal rhythm pattern, has been reported to prevent osteoporosis; however, its role in osteoclastogenesis remains unclear. In the present study, the ability of melatonin to inhibit receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis and the associated mechanism were investigated. Raw264.7 cells were cultured with RANKL (100 ng/ml) and macrophage colony-stimulating factor (M-CSF; 30 ng/ml) for 7 days, and tartrate-resistant acid phosphatase (TRAP) staining was used to detect osteoclastogenesis following treatment with melatonin. In addition, the effect of melatonin on cathepsin K and microRNA (miR)-882 expression was investigated via western blotting and reverse transcription-quantitative PCR. Melatonin significantly inhibited RANKL-induced osteoclastogenesis in Raw264.7 cells. From bioinformatics analysis, it was inferred that nuclear receptor subfamily 1 group D member 1 (NR1D1/Rev-erbα) may be a target of miR-882. In vitro, melatonin upregulated Rev-erbα expression and downregulated miR-882 expression in the osteoclastogenesis model. Rev-erbα overexpression boosted the anti-osteoclastogenesis effects of melatonin, whereas miR-882 partially diminished these effects. The present results indicated that the miR-882/Rev-erbα axis may serve a vital role in inhibiting osteoclastogenesis following RANKL and M-CSF treatment, indicating that Rev-erbα agonism or miR-882 inhibition may represent mechanisms through which melatonin prevents osteoporosis.

Synergistic effects of miR-708-5p and miR-708-3p accelerate the progression of osteoporosis

BACKGROUND

Bone homeostasis is a tightly orchestrated process maintained by osteoblasts and osteoclasts, and a disruption of their steady-state equilibrium can lead to the occurrence of osteoporosis (OP).

METHODS

We investigated the differential expression of micro (mi)RNAs in the bone tissues of a postmenopausal osteoporosis rat model induced by ovariectomy (OVX). Real-time PCR was used to verify the differentially expressed miRNAs in bone samples from OP patients and controls. The specific targets of two differentially expressed miRNAs in osteogenic or osteoclast differentiation were determined by bioinformatic prediction, and mRNA and protein detection.

RESULTS

miR-708-5p and miR-708-3p were highly expressed in the bone tissue of OVX rats and OP patients. miR-708-5p negatively regulated osteoblast differentiation in bone marrow mesenchymal stem cells by targeting SMAD specific E3 ubiquitin protein ligase 2, while miR-708-3p positively regulated osteoclast differentiation in bone marrow monocytes by targeting cerebellar degeneration associated protein 1 antisense RNA. miR-708-5p and miR-708-3p were shown to originate from the same precursor miRNA and to have a synergistic effect on the development of osteoporosis with different temporal and spatial patterns.

CONCLUSION

Our findings provide a referential theoretical basis and targets for the prevention and treatment of osteoporosis.

The Effect of Kinesitherapy on Bone Mineral Density in Primary Osteoporosis: A Systematic Review and Meta-Analysis of Randomized Controlled Trial

Objective

Osteoporosis (OP) is a well-established age-related disease, pathologically characterized by bone microarchitectural deterioration, increased fragility, and low BMD. Primary osteoporosis (POP) is the most common type of OP.

Methods

Publications pertaining to the effectiveness of kinesitherapy on BMD in POP from PubMed, SCI, Cochrane Library, Embase, VIP, CNKI, and Wanfang Database were retrieved from their inception to October 2019.

Results

A total of 21 studies with 1840 participants were included. The results of the meta-analysis revealed that kinesitherapy plus antiosteoporosis medications had a positive effect on lumbar spine BMD when the duration of intervention was 6 months (MD = 0.11 g/cm²; 95% CI: 0.06–0.15; P < 0.0001) or >6 months (MD = 0.04 g/cm²; 95% CI: 0.02–0.06; P < 0.0001) compared with antiosteoporosis medications alone. Additional kinesitherapy plus antiosteoporosis medications were associated with improved femoral neck BMD compared with antiosteoporosis medications alone (MD = 0.09 g/cm²; 95% CI: 0.03–0.16; P=0.004).

Conclusions

Kinesitherapy plus antiosteoporosis medications significantly improved lumbar spine and femoral neck BMD in the current low-quality evidence. Additional high-quality evidence is required to confirm the effect of kinesitherapy on BMD in patients with POP.

DAPT inhibits titanium particle-induced osteolysis by suppressing the RANKL/Notch2 signaling pathway

Artificial prosthesis is wildly used in clinical medicine for degenerative disease such as osteoclast-related diseases. However, the material wear particles released from the surface of prostheses cause prosthetic loosening as a result of aseptic osteolysis in long-term use. Therefore, it is important to find an agent that inhibits the formation and function of osteoclast for therapeutic use. Notch signaling pathway plays a lot of roles in cell proliferation, differentiation, and apoptosis. However, the role of Notch signaling pathway in osteoclastogenesis remains unclear. The aim of this study is to assess the effects of γ-secretase inhibitor DAPT on osteoclastogenesis via Notch signaling pathway in vitro and titanium particle-induced osteolysis in vivo. In animal experiments, the inhibitory effect of DAPT on titanium particle-induced osteolysis in a mouse calvaria model was demonstrated. Interestingly, few resorption pits were observed following administration of DAPT and almost no osteoclasts formed at high concentration of DAPT. in vitro experiments revealed the mechanism of the effects of DAPT on osteoclastogenesis. DAPT inhibited the formation and function of osteoclast by blocking RANKL-induced Notch2-NF-κB complex signaling pathway. In conclusion, these results indicated that DAPT could prevent and cure titanium particle-induced prosthetic loosening and other osteoclast-related diseases.

Calcium Bioavailability of Opuntia ficus-indica Cladodes in an Ovariectomized Rat Model of Postmenopausal Bone Loss

Osteoporosis is a disease of the skeletal system characterized by low bone mass and bone weakening, which increase the risk of fracture. This disease is associated with menopause because hypoestrogenism induces the maturation and activation of osteoclasts. In addition, a low dietary intake of calcium leads to low bone mineral density and postmenopausal osteoporosis. The objectives of this work were to determine calcium bioavailability of Opuntia ficus-indica cladodes at a late maturity stage and to assess its contribution in improving bone health in an ovariectomized rat model. Two-month-old Wistar female rats (n = 35) were used and distributed in seven experimental groups: (i) control group (Crtl), (ii) sham group (SH), (iii) ovariectomized group (OVX), (iv) ovariectomized group supplemented with calcium citrate (CCa), (v) ovariectomized group supplemented with O. ficus-indica powder (NI), (vi) ovariectomized group supplemented with soluble fiber from O. ficus-indica (FS) and (vii) ovariectomized group supplemented with insoluble fiber from O. ficus-indica (FI). Our results showed that calcium in the soluble fiber of O. ficus-indica is bioavailable and contributes to improve the physical, densitometric, biomechanical and microstructural properties of bones in ovariectomized rats. These findings indicated that O. ficus-indica cladodes at a late maturity stage represent a good source of bioavailable calcium and consumption of these cladodes might be beneficial for the prevention of osteoporosis and other bone diseases.

Risk of Osteoporotic Fracture in Patients with Breast Cancer: Meta-Analysis

Background

The fracture risk induced by anti-estrogen therapy in patients with breast cancer remains controversial. The aim of this study was to perform a meta-analysis and systematic review to evaluate the risk of osteoporotic fracture in patients with breast cancer.

Methods

A systematic search was performed to identify studies that included any osteoporotic fracture (hip fracture and vertebral fracture) in patients breast cancer. Main outcome measures were occurrence and risk of osteoporotic fractures including hip and vertebral fractures in patients and controls.

Results

A systematic search yielded a total of 4 studies that included osteoporotic fracture outcomes in patients with breast cancer. Meta-analysis showed a higher risk of osteoporotic fracture in patients with breast cancer. Analysis of these 4 studies involving a total of 127,722 (23,821 cases and 103,901 controls) patients showed that the incidence of osteoporotic fractures was higher in the breast cancer group than in the control group. The pooled estimate of crude relative risk for osteoporotic fracture was 1.35 (95% confidence interval, 1.29-1.42; P<0.001).

Conclusions

Although studies were limited by a small number, results suggested a possible association between anti-estrogen therapy and increased risk of osteoporotic fractures in patients with breast cancer.

MicroRNA levels in bone and blood change during bisphosphonate and teriparatide therapy in an animal model of postmenopausal osteoporosis

MicroRNAs control the activity of a variety of genes that are pivotal to bone metabolism. Therefore, the clinical utility of miRNAs as biomarkers and drug targets for bone diseases certainly merits further investigation. This study describes the use of an animal model of postmenopausal osteoporosis to generate a comprehensive dataset on miRNA regulation in bone tissue and peripheral blood during bone loss and specifically anti-resorptive and osteo-anabolic treatment. Forty-two Sprague-Dawley rats were randomized to SHAM surgery (n=10) or ovariectomy (OVX, n=32). Eight weeks after surgery, OVX animals were further randomized to anti-resorptive treatment with zoledronate (n=11), osteo-anabolic treatment with teriparatide (n=11), or vehicle treatment (n=10). After 12 weeks of treatment, bone and serum samples were used for microRNA analysis using next-generation sequencing (NGS), mRNA levels using RT-qPCR, and bone microarchitecture analysis using nanoCT. Ovariectomy resulted in loss of trabecular bone, which was fully rescued using osteo-anabolic treatment, and partially rescued using anti-resorptive treatment. NGS revealed that both, anti-resorptive and anabolic treatment had a significant impact on miRNA levels in bone tissue and serum: out of 426 detected miRNAs, 46 miRNAs were regulated by teriparatide treatment an d 10 by zoledronate treatment (p-adj.<0.1). Interestingly, teriparatide and zoledronate treatment were able to revert miRNA changes in tissue and serum of untreated OVX animals, such as the up-regulation of miR-203a-3p, a known osteo-inhibitory miRNA. We confirmed previously established mechanisms of miR-203a by analyzing its direct target Dlx5 in femoral head. Our data reveal a significant effect of ovariectomy-induced bone loss, as well as the two major types of anti-osteoporotic treatment on miRNA transcription in femoral head tissue. These changes are associated with altered activity of target genes relevant to bone formation, such as Dlx5. The observed effects of bone loss and treatment response on miRNA levels in bone are also reflected in the peripheral blood, suggesting the possibility of minimally-invasive monitoring of bone-derived miRNAs using liquid biopsies.

LncRNA CASC11 is upregulated in postmenopausal osteoporosis and is correlated with TNF-α

Purpose

In this study, we aimed to investigate the role of lncRNA cancer susceptibility 11 (CASC11) and tumor necrosis factor (TNF-α) in postmenopausal osteoporosis (POP).

Methods and materials

POP patients and healthy controls were included in this study and levels of CASC11 and TNF-α in plasma of those participants were measured by qPCR and Western blot, respectively. ROC curve was used for diagnostic analysis. Patients were followed up for 2 years and the correlations between the levels of CASC11 and TNF-α and disease conditions were analyzed.

Results

We found that CASC11 and TNF-α were both upregulated in plasma of POP patients than in healthy controls. Plasma levels of CASC11 and TNF-α were positively correlated in both POP patients and in healthy controls. Upregulation of CASC11 and TNF-α distinguished POP patients from healthy controls. Treatment and follow-up study showed that high CASC11 levels were significantly correlated with prolonged treatment course and high recurrence rate. Plasma levels of CASC11 and TNF-α decreased after treatment. CASC11 overexpression led to upregulated TNF-α in osteoclasts.

Conclusion

CASC11 is upregulated in POP and is correlated with TNF-α.

Zebrafish and medaka as models for biomedical research of bone diseases

The identification of disease-causing mutations has in recent years progressed immensely due to whole genome sequencing approaches using patient material. The task accordingly is shifting from gene identification to functional analysis of putative disease-causing genes, preferably in an in vivo setting which also allows testing of drug candidates or biotherapeutics in whole animal disease models. In this review, we highlight the advances made in the field of bone diseases using small laboratory fish, focusing on zebrafish and medaka. We particularly highlight those human conditions where teleost models are available.

LncRNA-NEF is downregulated in postmenopausal osteoporosis and is related to course of treatment and recurrence

Objectives

We investigated the role of long non-coding (lnc) RNA-NEF (neighboring enhancer of FoxA2), a characterized oncogene in cancer biology, in postmenopausal osteoporosis and its diagnostic and prognostic value in this disease.

Methods

Expression of lncRNA-NEF in plasma was detected by RNA extraction and real-time quantitative PCR. The diagnostic value of lncRNA-NEF and interleukin (IL)-6 for postmenopausal osteoporosis was evaluated by receiver operating characteristic curve analysis, with postmenopausal osteoporosis patients as true positive cases and healthy volunteers as true negative cases.

Results

We showed that plasma lncRNA-NEF was downregulated and plasma IL-6 was upregulated in postmenopausal osteoporosis patients compared with healthy controls. Altered plasma levels of lncRNA-NEF and IL-6 separated postmenopausal osteoporosis patients from healthy controls, and lncRNA-NEF and IL-6 were inversely and significantly correlated in osteoporosis patients. Patients were divided into high (n = 68) and low lncRNA-NEF (n = 73) groups according to Youden’s index. Patients with high lncRNA-NEF levels required a significantly shorter treatment course and had a lower post-treatment recurrence rate.

Conclusion

We showed that lncRNA-NEF is downregulated in postmenopausal osteoporosis and is related to course of treatment and recurrence. The involvement of lncRNA-NEF in postmenopausal osteoporosis is likely related to IL-6.

Effect of 2 years of endurance and high-impact training on preventing osteoporosis in postmenopausal women: randomized clinical trial

OBJECTIVE

The aim of the study was to analyze the effects of endurance and high-impact training oriented toward preventing osteoporosis in postmenopausal women with calcium and vitamin D supplementation.

METHODS

This study was a randomized clinical trial. Thirty-six postmenopausal women were randomized to the control and experimental groups. Thirty-four women completed the 2-year interventions. The control group training involved walking at an intense pace. The experimental group conducted high-impact training specifically oriented to prevent osteoporosis. Dual-energy x-ray absorptiometry was used to estimate the T-scores of the lumbar spine and femoral neck.

RESULTS

The fast-walking group showed constant T-scores in the femoral neck and improved T-scores in the lumbar spine. High-impact exercises produced improvements in both anatomical levels. Significant differences were found in the femoral neck (ΔControl = -0.04, ΔExperimental = 0.28). The differences were not significant in the lumbar spine (ΔControl = 0.27, ΔExperimental = 0.47). Cohen's effect size (d = 0.52) suggested a medium practical significance of the trial. The power was 51%.

CONCLUSIONS

Calcium plus vitamin D supplementation combined with specifically oriented exercises had a higher impact in the femoral neck than walking at an intense pace. As there were no differences at the lumbar spine level, the results were, however, inconclusive concerning which type of exercise was the most convenient. Importantly, the fact that the T-scores did not decrease after 2 years supports the belief that both proposed interventions can be conveniently used to prevent osteoporosis in postmenopausal women. A trial with a larger sample size would provide consistency to the findings and is warranted given the possible effects and benefits.

Dose of alendronate directly increases trabeculae expansivity without altering bone volume in rat femurs

AIM

To evaluate the effects of sodium alendronate on bone repair in fractures created in appendicular bones.

METHODS

Wistar rats (n = 36) were allocated into three distinct groups: group C (control), group B1 (received 1 mg/kg of alendronate), and group B2 (received 3 mg/kg of alendronate). The rats underwent femoral transversal linear fracture surgery using stable internal fixation with a 2.0 mm plate and screw system. Each animal randomly received intraperitoneal applications of sodium alendronate at a dose corresponding to group B1 or B2 three times a week, while the control group received a 0.9% saline solution. Drug administration was performed until euthanasia at 45 d. The femurs were removed and each surgical piece was sent for radiographic, tomographic and microtomographic analysis. Data were submitted to descriptive and inferential statistical analysis (95% confidence interval).

RESULTS

Quantitative evaluations of bone neoformation did not show differences among the groups in the radiographic (P = 0.341), microtomographic (P = 0.581) and tomographic evaluations (P = 0.171). In the qualitative microtomographic analysis, a smaller distance was observed between the internal bone trabeculae in the groups that used alendronate (P = 0.05). On the other hand, group B2 had a higher amount of bone trabeculae per unit length when compared to the other groups (P = 0.04).

CONCLUSION

It is likely that the use of alendronate did not have a direct influence on the amount of bone neoformation, however it did influence the bone quality in a dose-dependent manner, ultimately affecting the distance and quantity of the trabeculae.

Effect of Black Tea Extract and Thearubigins on Osteoporosis in Rats and Osteoclast Formation in vitro

Background: Osteoporosis is a major health problem that is closely related to substantial morbidity, mortality and decline in life quality for the aging population. Although previous studies and epidemiological evidence have demonstrated an association between black tea consumption and the prevention of bone loss, the underlying mechanism remains unclear. So, the effect of black tea extract (BTE) and thearubigins (TRs) on osteoporosis in rats and osteoclast formation in vitro were investigated.

Methods:In vivo, ovariectomized (OVX) rats were used to establish osteoporosis models. To validate the model and study the effects of BTE and TRs on osteoporosis, the female Wistar rats were divided into a sham-operated group and five OVX groups including model, Xian-Ling-Gu-Bao (XLGB) (as a positive control), BTE, TRs low-dose, and TRs high-dose group. The rats in the four treatment groups were given the corresponding test sample for 12 weeks. Then, the body weight, femur indices, and serum biomarkers were examined and analyzed. In vitro, RAW264.7 murine macrophages were used as model of osteoclast formation. The effects of BTE and TRs on osteoclasts formation and the specific genes and protein levels of osteoclasts were determined.

Results: Although there was no significant effect on the OVX-induced body weight gain by BTE or TRs, the levels of maximum bending force, cortical bone thickness and biomarker of bone resorption (acid phosphatase) can be significantly ameliorated by BTE or TRs in OVX rats. Furthermore, both of BTE and TRs can inhibit the osteoclastogenesis and diminish the expression levels of the related genes and proteins.

Effect of Local Application of Alendronate and Parathyroid Hormone on Craniofacial Bone Repair - a Preliminary Study

This study aimed to evaluate the effect of two methods of local application of alendronate and parathyroid hormone (PTH) on bone repair and the systemic implications. A critically sized defect (5 mm) was created in the cranial region of twenty-five male Wistar rats, and the bone removed was particulated, and grafted back to the defect with different treatments. The animals were randomly divided into five groups: A1- bone graft immersion in alendronate solution (3 mg/kg) for 5 minutes; P1- bone graft immersion in PTH solution (20 µg); A2- weekly local applications of alendronate 1 mg/kg; P2- weekly local applications of PTH (20 µg); C- no drugs were used. The animals were euthanized 60 days after surgery. Cranial bone blocks were removed for histological, histomorphometric, and immunohistochemical analyses. MMP-2 and MMP-9 were used for immunolabeling. The kidneys, liver, and brain were also removed from all the rats for histological analysis. The data were submitted for statistical analysis with a level of significance of 0.05 (One-way ANOVA). The group C and group P2 presented a higher quantity of viable bone particles than the remaining groups. Groups A1, A2, and P1 presented with fewer viable bone particles than the control group, with a predominance of non-mineralized connective tissue. The histomorphometric analysis revealed no differences in relative bone area or MMP-2 or MMP-9 immunolabeling between the groups (p>0.05). Group A2 showed presence of fat in the liver consistent with hepatic steatosis. Changes in brain tissue were observed in groups A1 and P1.

Liuwei Dihuang pill cures postmenopausal osteoporosis with kidney-Yin deficiency: Potential therapeutic targets identified based on gene expression profiling

This study aimed to investigate the potential therapeutic targets of Liuwei Dihuang pill (LDP) in the treatment of postmenopausal osteoporosis with kidney-Yin deficiency (PMO-KY).Gene expression data were downloaded from the GEO database, including 4 PMO-KY samples and 3 healthy postmenopausal controls from GSE56116, as well as 3 PMO-KY samples before LDP treatment and 3 PMO-KY samples after three months of LDP treatment from GSE57273. Limma package was used to identify differentially expressed genes (DEGs). Afterwards, the potential target genes of LDP (namely key DEGs) were identified according to the comparison of DEGs in PMO-KY group and the DEGs in LDP treatment groups. Subsequently, iRegulon plugin in Cytoscape software was used to predict potential transcription factors (TFs) that regulated the key DEGs, and Comparative Toxicogenomics Database was utilized to identify known PMO-related genes among the key DEGs.Totally, 202 and 2066 DEGs were identified between PMO-KY and controls, as well as after-treatment and before-treatment groups, respectively. Among them, 52 DEGs were up-regulated in PMO-KY but down-regulated after LDP treatment, and 8 TFs were predicted to these DEGs. Furthermore, 34 DEGs were down-regulated in PMO-KY but up-regulated after treatment, and 7 TFs were predicted to regulate these DEGs. Additionally, 43 of the 86 key DEGs were known PMO-related genes.NCOA3, TCF4, DUSP6, PELI2, and STX7 were predicted to be regulated by HOXA13. In the PMO-KY treatment, NCOA3, TCF4, DUSP6, PELI2, and STX7 might be the potential therapeutic targets of LDP. However, further investigation is required to confirm these genes.

Effect of Strontium Ranelate on the Muscle and Vertebrae of Ovariectomized Rats

Osteoporosis is often accompanied by sarcopenia. The effect of strontium ranelate (SR) on muscle tissue has not been investigated sufficiently. In this study, the effect of different SR treatments on muscle was studied. Additionally, the lumbar vertebrae were analyzed. Three-month-old female rats were divided into five groups (n = 12): Group 1: untreated (NON-OVX); Group 2: ovariectomized and left untreated (OVX); Group 3: SR after OVX until the study ended (13 weeks, SR prophylaxis and therapy = pr+th); Group 4: OVX and SR for 8 weeks (SR prophylaxis = pr); Group 5: SR for 5 weeks from the 8 week after OVX (SR therapy = SR th). SR was applied in food (630 mg/kg body weight). The size of muscle fibers, capillary density, metabolic enzymes, and mRNA expression were assessed in soleus, gastrocnemius, and longissimus muscles. The vertebral bodies underwent micro-CT, biomechanical, and ashing analyses. In general, SR did not alter the muscle histological parameters. The changes in fiber size and capillary ratio were related to the body weight. Myostatin mRNA was decreased in Sr pr+th; protein expression was not changed. SR th led to increase in mRNA expression of vascular endothelial growth factor (Vegf-B). In lumbar spine, SR pr+th enhanced biomechanical properties, bone mineral density, trabecular area, density, and thickness and cortical density. The reduced calcium/phosphate ratio in the SR pr+th group indicates the replacement of calcium by strontium ions. SR has no adverse effects on muscle tissue and it shows a favorable time-dependent effect on vertebrae. A functional analysis of muscles could verify these findings.

Application of bone transgenic zebrafish in anti-osteoporosis chemical screening

BACKGROUND

The zebrafish (Danio rerio) has recently been shown to be an ideal model to study bone disease including osteoporosis. The zebrafish osteoporosis model could be induced by glucocorticoid treatment with chemical staining for reflecting the level of bone mineralization. However, this methodology was unstable. Here, we developed a novel methodology to directly evaluate the bone mass and density.

METHODS

We generated and used the bone of transgenic zebrafish Tg (ola.sp7:nlsGFP) to evaluate the bone mass and density by measuring the areal extent and the integrated optical density (IOD) of enhanced green fluorescent protein (eGFP). This methodology was further compared with the traditional chemically stained method showing the bone mineralization. Furthermore, genes related to zebrafish osteoporosis were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR).

RESULTS

Our results of new methods were consistent with those from chemically stained fish, following glucocorticoid-induction or epimedium flavonoid (FE)-rescue treatments. qRT-PCR analyses on mRNA levels revealed that glucocorticoid induces osteoporosis by downregulating the expression of osteoblast-related factors osterix, osteocalcin, and osteopontin, and upregulating the expression of osteoclast-related factor tartrate-resistant acid phosphatase. In FE-rescued fish, the expression of osteogenic factors osterix, osteocalcin, and osteopontin were increased.

CONCLUSION

Compared to the traditional chemical staining methods, the new osteoporosis model using Tg(ola.sp7:nlsGFP) is more convenient and efficient for studying osteoporosis in vivo, and especially for high-throughput anti-osteoporosis drug screening.

miRNA-133a-5p Inhibits the Expression of Osteoblast Differentiation-Associated Markers by Targeting the 3' UTR of RUNX2

Recent studies have recognized the involvement of microRNAs (miRNAs) in the development of osteoporosis, which regulate the balance between osteogenesis and osteoclasis. In this study, we investigated the regulation by miRNA-133a-5p on the osteoblast differentiation-associated markers in the mouse osteoblast-like MC3T3-E1 cells by RUNX2. First, we manipulated the miRNA-133a level in the MC3T3-E1 cells with 20 or 40 nM miR-133a-5p mimics, miR-133a-5p inhibitor, or scramble miRNA. Then, we quantified with real-time polymerase chain reaction (qRT-PCR) the expression of Collagen I, osteocalcin (OCN), and osteopontin (OPN) in the miR-133a-5p-manipulated MC3T3-E1 cells. And the confocal microscopy was also utilized to confirm the regulation by miR-133a-5p on the expression of the three molecules. We also investigated the extracellular matrix (ECM) mineralization and the alkaline phosphatase (ALP) activity in the miR-133a-5p-manipulated MC3T3-E1 cells. In addition, we explored the possible targeting by miR-133a-5p on RUNX2, which was a well-recognized promoter to osteoblast differentiation, with luciferase reporter, qRT-PCR, and Western blotting assay. Results demonstrated that the miRNA-133a-5p mimics markedly reduced, whereas the miRNA-133a-5p inhibitor significantly promoted the expression of Collagen I, OCN, and OPN, the ECM mineralization, and the ALP activity in MC3T3-E1 cells. The alignment analysis demonstrated a high homology between miRNA-133a-5p and the 3' UTR of RUNX2. Moreover, the luciferase reporter assay demonstrated that miRNA-133a-5p targeted the 3' UTR of RUNX2, and inhibited the expression of RUNX2 in both mRNA and protein levels. In conclusion, we identified the inhibition by miRNA-133a-5p to the expression of osteoblast differentiation markers, to the ECM mineralization, and to the ALP activity in MC3T3-E1 cells, by targeting the 3' UTR of RUNX2. Our study suggests that miRNA-133a-5p might be an important target to inhibit osteoblast differentiation in osteoporosis.

Psoralen stimulates osteoblast proliferation through the activation of nuclear factor-κB-mitogen-activated protein kinase signaling

Osteoporosis is a systemic skeletal disease that leads to increased bone fragility and susceptibility to fracture. Approximately 50% of postmenopausal women develop osteoporosis as a result of postmenopausal estrogen deficiency. To reduce fractures related to osteoporosis in women, previous studies have focused on therapeutic strategies that aim to increase bone formation or decrease bone resorption. However, pharmacological agents that aim to improve bone fracture susceptibility exhibit side effects. Current studies are investigating natural alternatives that possess the benefits of selective estrogen receptor modulators (SERMs) without the adverse effects. Recent studies have indicated that phytoestrogen may be an ideal natural SERM for the treatment of osteoporosis. In Chinese herbal medicine, psoralen, as the predominant substance of Psoralea corylifolia, is considered to be a phytoestrogen and is used as a remedy for osteoporosis. A number of studies have demonstrated the efficacy of psoralen in bone formation. However, the pathways and underlying molecular mechanisms that participate in psoralen-induced osteoblast formation are not well understood. In the present study, hFOB1.19 cells were treated with psoralen at different concentrations (0, 5, 10, 15 and 20 µM) for 0, 24, 36, 48 and 72 h, respectively. Reverse transcription-quantitative polymerase chain reaction and western blot assays were performed to detect glucose transporter 3 (GLUT3) expression. A cell counting kit-8 assay was used to analyze cell proliferation. In addition the effects of mitogen activated protein kinase inhibitors on extracellular signal-regulated kinase (ERK), phosphorylated (p)-ERK, p38, p-p38, c-Jun N-terminal kinase (JNK) and p-JNK expressions and cell proliferation were measured, as was the effect of nuclear factor (NF)-κB inhibitor on P65 and GLUT3 expressions and cell proliferation. The results indicated that psoralen stimulates hFOB1.19 cell proliferation in a dose-dependent manner (P<0.05). Phospho-ERK, p38 and JNK were markedly increased by psoralen compared with the control group (P<0.05), and the specific inhibitors of ERK (SCH772984), p38 (SB203580) and JNK (SP600125) reversed the stimulatory effects of psoralen on signal marker phosphorylation (P<0.05). The rate of psoralen-induced cell proliferation was significantly suppressed by inhibitors of ERK, JNK and p38 compared with psoralen treatment alone (P<0.05). In addition, psoralen stimulated osteoblast proliferation via the NF-κB signaling pathway. Therefore, the present findings suggest that psoralen may be a potential natural alternative to SERMs in the treatment of osteoporosis and fractures.

Effect of isopsoralen on Smad7 in osteoblastic MC3T3-E1 cells

The primary pathological change in postmenopausal osteoporosis (PM-OP) is bone collagen loss caused by estrogen depletion. Osteoblasts synthesize type I collagen, which composes the organic matrix of bone. Although isopsoralen stimulates osteoblastic cell proliferation and differentiation, transforming growth factor (TGF)-β1 is an important cell signaling factor for stimulating collagen synthesis. To explore the association between isopsoralen and the synthesis of collagen in vitro, the molecular and biological association between isopsoralen and TGF-β signaling was examined. (CAGA) 12-luciferase-reporter gene was used to measure TGF-β1 signaling activity. Type I collagen was detected by semiquantitative reverse transcription polymerase chain reaction, and mothers against decapentaplegic homolog 7 (Smad7) protein expression levels were analyzed by western blotting. The expression of collagen in MC3T3-E1 cells stimulated with isopsoralen was significantly upregulated compared with the control groups (P<0.05). Conversely, isopsoralen significantly decreased Smad7 protein expression compared with the control groups (P<0.05). Moreover, it was observed that isopsoralen activates the TGF-β1 signaling pathway and ultimately promotes collagen synthesis through inhibition of Smad7 protein expression. Therefore, isopsoralen is a potential target for the treatment of PM-OP.

Total flavonoids from Rhizoma Drynariae (Gusuibu) for treating osteoporotic fractures: implication in clinical practice

This systematic review was performed to determine the clinical efficacy and safety of total flavonoids from Rhizoma Drynariae (TFRD) for osteoporotic fractures and to provide clear evidence for clinical practice. Eight databases were searched to identify relevant randomized controlled trials (RCTs) until December 2016. Six RCTs involving 846 patients were included. The primary outcomes included fracture recurrence and death. Meta-analysis showed that both the combination therapy and TFRD alone were better than conventional treatments in improving bone mineral density (BMD) value (weighted mean difference [WMD] =3.68, 95% confidence interval [CI]: 0.01 to 0.04, P=0.0002), (WMD =0.14; 95% CI: 0.11 to 0.16; P<0.00001), respectively, and enhancing therapeutic effect (OR =0.25; 95% CI: 0.12 to 0.51; P=0.0002). Thirty-three patients experienced adverse drug reactions (ADRs), none of the ADRs were severe and all were resolved after symptomatic treatments. Gastrointestinal symptoms were the most common ADRs in the usage of TFRD. Overall, the effect of TFRD on osteoporotic fractures was supported by improving BMD and therapeutic effect. Due to the methodological drawbacks of the included studies, the conclusions should be treated with caution for future research. Registration number: CRD42017052797.

Short term sodium alendronate administration improves the peri-implant bone quality in osteoporotic animals

Sodium alendronate is a bisphosphonate drug that exerts antiresorptive action and is used to treat osteoporosis.

Puerarin prevents bone loss in ovariectomized mice and inhibits osteoclast formation in vitro

The present study aimed at investigating the effects of Puerarin (PR), a major isoflavonoid isolated from the Chinese medicinal herb Puerariae radix, on bone metabolism and the underlying mechanism of action. The in vivo assay, female mice were ovariectomized (OVX), and the OVX mice were fed with a diet containing low, middle, and high doses of PR (2, 4, and 8 mg·d(-1), respectively) or 17β-estradiol (E2, 0.03 μg·d(-1)) for 4 weeks. In OVX mice, the uterine weight declined, and intake of PR at any dose did not affect uterine weight, compared with the control. The total femoral bone mineral density (BMD) was significantly reduced by OVX, which was reversed by intake of the diet with PR at any dose, especially at the low dose. In the in vitro assay, RAW264.7 cells were used for studying the direct effect of PR on the formation of osteoclasts. PR reduced the formation of tartrate resistant acid phosphatase (TRAP)-positive multi-nucleated cells in the RAW 264.7 cells induced by receptor activator for nuclear factor-κB Ligand (RANKL). MC3T3-E1 cells were used for studying the effects of PR on the expression of osteoprotegerin (OPG) and RANKL mRNA expression in osteoblasts. The expression of OPG mRNA and RANKL mRNA was detected by RT-PCR on Days of 5, 7, 10, and 12 after PR exposure. PR time-dependently enhanced the expression of OPG mRNA and reduced the expression of RANKL mRNA in MC3T3-E1 cells. In conclusion, our results suggest that PR can effectively prevent bone loss in OVX mice without any hyperplastic effect on the uterus, and the antiosteoporosis activity of PR may be related to its effects on the formation of osteoclasts and the expression of RANKL OPG in osteoblasts.

Selective Estrogen Receptor Modulators Suppress Hif1α Protein Accumulation in Mouse Osteoclasts

Anti-bone resorptive drugs such as bisphosphonates, the anti-RANKL antibody (denosumab), or selective estrogen receptor modulators (SERMs) have been developed to treat osteoporosis. Mechanisms underlying activity of bisphosphonates or denosumab in this context are understood, while it is less clear how SERMs like tamoxifen, raloxifene, or bazedoxifene inhibit bone resorption. Recently, accumulation of hypoxia inducible factor 1 alpha (Hif1α) in osteoclasts was shown to be suppressed by estrogen in normal cells. In addition, osteoclast activation and decreased bone mass seen in estrogen-deficient conditions was found to require Hif1α. Here, we used western blot analysis of cultured osteoclast precursor cells to show that tamoxifen, raloxifene, or bazedoxifene all suppress Hif1α protein accumulation. The effects of each SERM on osteoclast differentiation differed in vitro. Our results suggest that interventions such as the SERMs evaluated here could be useful to inhibit Hif1α and osteoclast activity under estrogen-deficient conditions.

Selective Estrogen Receptor Modulators

Selective estrogen receptor modulators (SERMs) are now being used as a treatment for breast cancer, osteoporosis and postmenopausal symptoms, as these drugs have features that can act as an estrogen agonist and an antagonist, depending on the target tissue. After tamoxifen, raloxifene, lasofoxifene and bazedoxifene SERMs have been developed and used for treatment. The clinically decisive difference among these drugs (i.e., the key difference) is their endometrial safety. Compared to bisphosphonate drug formulations for osteoporosis, SERMs are to be used primarily in postmenopausal women of younger age and are particularly recommended if there is a family history of invasive breast cancer, as their use greatly reduces the incidence of this type of cancer in women. Among the above mentioned SERMs, raloxifene has been widely used in prevention and treatment of postmenopausal osteoporosis and vertebral compression fractures, and clinical studies are now underway to test the comparative advantages of raloxifene with those of bazedoxifene, a more recently developed SERM. Research on a number of adverse side effects of SERM agents is being performed to determine the long-term safety of this class of compouds for treatment of osteoporosis.

Myricetin Prevents Alveolar Bone Loss in an Experimental Ovariectomized Mouse Model of Periodontitis

Periodontitis is a common chronic inflammatory disease, which leads to alveolar bone resorption. Healthy and functional alveolar bone, which can support the teeth and enable their movement, is very important for orthodontic treatment. Myricetin inhibited osteoclastogenesis by suppressing the expression of some genes, signaling pathways, and cytokines. This study aimed to investigate the effects of myricetin on alveolar bone loss in an ovariectomized (OVX) mouse model of periodontitis as well as in vitro osteoclast formation and bone resorption. Twenty-four healthy eight-week-old C57BL/J6 female mice were assigned randomly to four groups: phosphate-buffered saline (PBS) control (sham) OVX + ligature + PBS (vehicle), and OVX + ligature + low or high (2 or 5 mg∙kg⁻¹∙day⁻¹, respectively) doses of myricetin. Myricetin or PBS was injected intraperitoneally (i.p.) every other day for 30 days. The maxillae were collected and subjected to further examination, including micro-computed tomography (micro-CT), hematoxylin and eosin (H&E) staining, and tartrate-resistant acid phosphatase (TRAP) staining; a resorption pit assay was also performed in vitro to evaluate the effects of myricetin on receptor activator of nuclear factor κ-B ligand (RANKL)-induced osteoclastogenesis. Myricetin, at both high and low doses, prevented alveolar bone resorption and increased alveolar crest height in the mouse model and inhibited osteoclast formation and bone resorption in vitro. However, myricetin was more effective at high dose than at low dose. Our study demonstrated that myricetin had a positive effect on alveolar bone resorption in an OVX mouse model of periodontitis and, therefore, may be a potential agent for the treatment of periodontitis and osteoporosis.

Estrogen Deficiency Leads to Further Bone Loss in the Mandible of CKD Mice

Background

Chronic kidney disease (CKD) has been regarded as a grave public health problem. Estrogen is a critical factor for both renal protection and bone remodeling. Our previous study demonstrated that CKD impairs the healing of titanium implants. The aim of this study was to investigate the effects of estrogen deficiency on the mandibular bone in CKD mice.

Methods

Forty eleven-week-old female C57BL mice were used in this study. Uremia and estrogen deficiency were induced by 5/6 nephrectomy and ovariectomy (OVX), respectively. After 8 weeks, the mice were sacrificed, and their mandibles were collected for micro-CT analysis and histological examination.

Results

All the mice survived the experimental period. Serum measurements confirmed a significant increase in BUN in the CKD group that was further increased by OVX. OVX led to significant decreases in both the BV/TV and cortical thickness of the mandibular bone in CKD mice.

Conclusion

In summary, our findings indicate that estrogen deficiency leads to further mandibular bone loss in CKD mice.

Urban-rural differences in the uptake of new oral bisphosphonate formulations

We identified significantly slower uptake, and consistently lower proportions of new oral bisphosphonate formulations dispensed in rural regions compared to urban regions of Ontario. Further research examining regional differences in outcomes may provide insight as to whether urban-rural differences in prescribing translate into health disparities between regions.

PURPOSE

The aim of this study was to examine urban-rural differences in the uptake of new oral bisphosphonate formulations available on the Ontario drug formulary: alendronate + vitamin D3 (January 2007), monthly risedronate (June 2009), and risedronate delayed-release (February 2012).

METHODS

We plotted the monthly proportion of new formulation claims of all claims with the same drug molecule, from their formulary listing date until March 2014. Results were stratified by major urban, nonmajor urban, and rural regions as defined by the Rurality Index of Ontario. We compared the rate of uptake over the first year of formulary availability using linear regression, and compared proportions dispensed between regions using chi-squared tests.

RESULTS

We identified a regional gradient in uptake for alendronate + vitamin D3 and monthly risedronate; major urban regions had the fastest uptake, followed by nonmajor urban regions, and rural regions had the slowest uptake. Rural regions also had the slowest uptake of risedronate delayed-release; however, uptake in major urban and nonmajor urban regions were similar. Rural regions dispensed the lowest proportions for all new formulations 1 year after formulary availability: alendronate + vitamin D3 (32% major urban, 23% nonmajor urban, 12% rural), monthly risedronate (26% major urban, 21% nonmajor urban, 16% rural), and risedronate delayed-release (21% major urban, 22 % nonmajor urban, 13% rural). This pattern persisted throughout our study.

CONCLUSION

We identified significantly slower uptake and lower proportions of new formulations dispensed in rural regions compared to urban regions. Further research examining regional differences in outcomes may demonstrate whether urban-rural differences in prescribing translate into health disparities between regions.

Mulberry water extract regulates the osteoblast/osteoclast balance in an ovariectomic rat model

Mulberry has favorable antioxidant ability.

Effect of three months of periodized hydrogymnastics exercise program on urinary concentration of deoxypyridinoline in older women

OBJECTIVE

To determine the effect of three months of periodized hydrogymnastics exercise program on urinary concentration of deoxypyridinoline in older women.

SUBJECTS AND METHODS

Twenty-six subjects were randomly assigned in two, intervention group (n = 16) and control group (n = 10). The intervention group followed 12-week of periodized hydrogymnastics training program five times a week, 50 minutes of water exercise with work heart rate reserve of 40-50% (1-6th week) increasing the load to 50-60% (7-12th week); the control group was not involved in exercise and remained sedentary. The urinary concentration of deoxypyridinoline was evaluated by high resolution liquid chromatography using the reactive immulite pyrilinks-D siemens medical solutions, pretest at the baseline and at the end post-test of the 12-week of water-exercise. As statistical analyses mixed 2 x 2 ANOVA was used, also percentage changes (Δ %) was calculated.

RESULTS

The results did not show significant improvement (p < 0.05) comparing the interaction intergroup and the measurements of urinary concentration of deoxypyridinoline (p = 0.504), percentage change (Δ %) showed positive improvements in the experimental group of -13.7 (nM/mMcreatine) in comparison with -7.1 (nM/mMcreatine) from the control group.

CONCLUSION

The present study involves periodization increasing the load heart rate reserve of hydrogymnastics exercise in order to produce grater adaptations, but the results showed than is not possible to infer that hydrogymnastics is effective in increase urinary concentration of deoxypyridinoline in older women, will be appropriated in the future more studies to better clarify the possibilities of improvements between hydrogymnastics and urinary concentration of deoxypyridinoline.

MicroRNA-210 is involved in the regulation of postmenopausal osteoporosis through promotion of VEGF expression and osteoblast differentiation

MicroRNAs (miRNAs) are small non-protein-codingRNAs that function as negative gene expression regulators. miRNA-210 (miR-210) has recently been recognized in the pathogenesis of osteonecrosis associated with angiogenesis. Herein we aimed to explore the clinical significance of miR-210 treatment for postmenopausal osteoporosis. The expression of miR-210 was detected in bone marrow mesenchymal stem cells (BMSCs) in vitro and miR-210 significantly promoted the expression of vascular edothelial growth factor (VEGF) in BMSCs in a time-dependent manner (p<0.05). And miR-210 suppressed PPARγ expression but increased the expression of ALP and osterix, demonstrating that miR-210 inhibited adipocyte differentiation and promoted osteoblast differentiation of BMSCs in vitro. The protein expression of hypoxia-inducible factor 1 alpha (HIF-1α) and VEGF in 17β-estradiol (E2) treated osteoblasts were significantly increased in a dose- and time-dependent manner (p<0.05). And E2 inducted the VEGF expression through the PI3K/AKT signaling pathway in osteoblasts. Taken together, these data implied that miR-210 played an important role in ameliorating the estrogen deficiency caused-postmenopausal osteoporosis through promotion the VEGF expression and osteoblast differentiation.

Alendronate, a double-edged sword acting in the mevalonate pathway

Aminobisphosphonate aledronate is a compound commonly used clinically for the treatment of osteoporosis and other bone diseases, as a result of it preventing bone resorption. However, in previous years it has also been used to obtain cellular and animal models of a rare genetic disorder termed Mevalonate Kinase Deficiency (MKD). MKD is caused by mutations affecting the mevalonate kinase enzyme, in the cholesterol pathway and alendronate can be used to biochemically mimic the genetic defect as it inhibits farnesyl pyrophosphate synthase in the same pathway. Despite evidence in favor of the inhibition exerted on the mevalonate pathway, there is at least one clinical case of MKD in which alendronate improved not only skeletal and bone fractures, as expected, but also MKD clinical features. Based on this finding, the present study assessed the anti‑inflammatory properties of this aminobisphosphonate in vitro. No anti‑inflammatory effects of alendronate were observed in the in vitro experiments. Since MKD lacks specific treatments, these results may assist scientists and physicians in making the decision as to the most suitable choice of therapeutic compounds for this neglected disease.