Oxidative Stress and Osteoporosis

Pharmacological mechanism of natural antidepressants: The role of mitochondrial quality control

BACKGROUND

Depression is a mental illness characterized by persistent sadness and a reduced capacity for pleasure. In clinical practice, SSRIs and other medications are commonly used for therapy, despite their various side effects. Natural products present distinct advantages, including synergistic interactions among multiple components and targeting multiple pathways, suggesting their tremendous potential in depression treatment. Imbalance in mitochondrial quality control (MQC) plays a significant role in the pathology of depression, emphasizing the importance of regulating MQC as a potential intervention strategy in addressing the onset and progression of depression. However, the role and mechanism through which natural products regulate MQC in depression treatments still need to be comprehensively elucidated, particularly in clinical and preclinical settings.

PURPOSE

This review was aimed to summarize the findings of recent studies and outline the pharmacological mechanisms by which natural products modulate MQC to exert antidepressant effects. Additionally, it evaluated current research limitations and proposed new strategies for future preclinical and clinical applications in the depression domain.

METHODS

To study the main pharmacological mechanisms underlying the regulation of MQC by natural products in the treatment of depression, we conducted a thorough search across databases such as PubMed, Web of Science, and ScienceDirect databases to classify and summarize the relationship between MQC and depression, as well as the regulatory mechanisms of natural products.

RESULTS

Numerous studies have shown that irregularities in the MQC system play an important role in the pathology of depression, and the regulation of the MQC system is involved in antidepressant treatments. Natural products mainly regulate the MQC system to induce antidepressant effects by alleviating oxidative stress, balancing ATP levels, promoting mitophagy, maintaining calcium homeostasis, optimizing mitochondrial dynamics, regulating mitochondrial membrane potential, and enhancing mitochondrial biogenesis.

CONCLUSIONS

We comprehensively summarized the regulation of natural products on the MQC system in antidepressants, providing a unique perspective for the application of natural products within antidepressant therapy. However, extensive efforts are imperative in clinical and preclinical investigations to delve deeper into the mechanisms underlying how antidepressant medications impact MQC, which is crucial for the development of effective antidepressant treatments.

Luteolin rescues postmenopausal osteoporosis elicited by OVX through alleviating osteoblast pyroptosis via activating PI3K-AKT signaling

BACKGROUND

Recently, osteoblast pyroptosis has been proposed as a potential pathogenic mechanism underlying osteoporosis, although this remains to be confirmed. Luteolin (Lut), a flavonoid phytochemical, plays a critical role in the anti-osteoporosis effects of many traditional Chinese medicine prescriptions. However, its protective impact on osteoblasts in postmenopausal osteoporosis (PMOP) has not been elucidated.

PURPOSE

This research aimed to determine the effect of Lut in ameliorating PMOP by alleviating osteoblast pyroptosis and sustaining osteogenesis.

STUDY DESIGN

This research was designed to investigate the novel mechanism of Lut in alleviating PMOP both in cell and animal models.

METHODS

Ovariectomy-induced PMOP models were established in mice with/without daily gavaged of 10 or 20 mg/kg body weight Lut. The impact of Lut on bone microstructure, metabolism and oxidative stress was evaluated with 0.104 mg/kg body weight Estradiol Valerate Tablets daily gavaged as positive control. Network pharmacological analysis and molecular docking were employed to investigate the mechanisms of Lut in PMOP treatment. Subsequently, the impacts of Lut on the PI3K/AKT axis, oxidative stress, mitochondria, and osteoblast pyroptosis were assessed. In vitro, cultured MC3T3-E1(14) cells were exposed to H2O2 with/without Lut to examine its effects on the PI3K/AKT signaling pathway, osteogenic differentiation, mitochondrial function, and osteoblast pyroptosis.

RESULTS

Our findings demonstrated that 20 mg/kg Lut, similar to the positive control drug, effectively reduced systemic bone loss and oxidative stress, and enhanced bone metabolism induced by ovariectomy. Network pharmacological analysis and molecular docking indicated that the PI3K/AKT axis was a potential target, with oxidative stress response and nuclear membrane function being key mechanisms. Consequently, the effects of Lut on the PI3K/AKT axis and pyroptosis were investigated. In vivo data revealed that the PI3K/AKT axis was deactivated following ovariectomy, and Lut restored the phosphorylation of key proteins, thereby reactivating the axis. Additionally, Lut alleviated osteoblast pyroptosis and mitochondrial abnormalities induced by ovariectomy. In vitro, Lut intervention mitigated the inhibition of the PI3K/AKT axis and osteogenesis, as well as H2O2-induced pyroptosis. Furthermore, Lut attenuated ROS accumulation and mitochondrial dysfunction. The effects of Lut, including osteogenesis restoration, anti-pyroptosis, and mitochondrial maintenance, were all reversed with LY294002 (a PI3K/AKT pathway inhibitor).

CONCLUSION

In summary, Lut could improve mitochondrial dysfunction, alleviate GSDME-mediated pyroptosis and maintain osteogenesis via activating the PI3K/AKT axis, offering a new therapeutic strategy for PMOP.

Risk factors for decreased bone mineral density in patients with metabolic dysfunction-associated steatotic liver disease: A cross-sectional study at a health examination center

BACKGROUND & AIMS

Steatotic liver disease (SLD) is often detected in health examinations. However, although individuals with metabolic dysfunction-associated SLD (MASLD) may have decreased bone mineral density (BMD), the specific risk factors remain unclarified. The objective of this study was to identify the factors associated with decreased BMD in patients with MASLD.

METHODS

Individuals who underwent abdominal ultrasonography and BMD measurements at our healthcare center were included. The BMD of the calcaneus was assessed using an AOS-10SA bone densitometer. Decreased BMD was defined as a T-score below -1.0 SD or the administration of osteoporosis treatment. SLD was diagnosed based on specific ultrasonographic criteria.

RESULTS

A total of 1410 patients were diagnosed with MASLD. The median age was 52 years. Multivariate analysis using a logistic regression model revealed that the independent predictors of decreased BMD were a low body mass index (BMI) or a small waist circumference (odds ratio (OR): 0.48, 95% confidence interval (CI): 0.34-0.67), hypertriglyceridemia (OR: 1.29, 95% CI: 1.00-1.65), and a weak grip strength (OR: 0.98, 95% CI: 0.97-1.00). Subgroup analyses of individuals aged 50 years or older, men, and individuals with a FIB-4 index of 1.3 or greater revealed that the absence of a high BMI or a large waist circumference was associated with decreased BMD. The subgroup analysis of men revealed that a weaker grip strength was associated with decreased BMD.

CONCLUSION

The present study suggested several potential risk factors for decreased BMD in patients with MASLD. Individuals with the abovementioned risk factors should be encouraged to undergo BMD measurement from the perspective of preventive medicine.

Associations of global biomarkers of oxidative stress with osteoporosis, bone microstructure and bone turnover: Evidence from human and animal studies

PURPOSE

Human evidence on the association between oxidative stress and osteoporosis is inconsistent. Fluorescent Oxidation Products (FlOPs) are global biomarkers of oxidative stress. We examined the associations of FlOPs (excitation/emission wavelengths 320/420 nm for FlOP_320, 360/420 nm for FlOP_360, and 400/475 nm for FlOP_400) with osteoporosis, bone microstructure, and bone turnover markers in humans and rats.

METHODS

In humans, we conducted a 1:2 age, sex, hospital, and specimen-matched case-control study to test the association between FlOPs and osteoporosis diagnosed from dual-energy X-ray absorptiometry. In eight-week-old male Wistar rats, we administrated D-galactose and 0.9 % saline for 90 days in treatment and control groups (n = 8/group); micro-CT was used to determine bone microstructure.

RESULTS

In humans, higher levels of FlOP_320 (OR for per 1 SD increase = 1.49, 95 % CI: 1.01-2.20) and FlOP_360 (OR for per 1 SD increase = 1.59, 95 % CI: 1.07-2.37) were associated with increased odds of osteoporosis. FlOP_400 were not associated with osteoporosis. D-galactose treated rats, as compared with control rats, showed higher levels of FlOP_320 and MDA, and lower P1NP levels during 90 days of experiment (all P < 0.05). The D-galactose group had lower trabecular bone volume fraction (0.07 ± 0.03 vs. 0.13 ± 0.05; P = 0.008) and volumetric BMD (225.4 ± 13.8 vs. 279.1 ± 33.2 mg HA/cm3; P = 0.001) than the control group.

CONCLUSION

In conclusion, higher FlOP_320 levels were associated with increased odds of osteoporosis, impaired bone microstructure and decreased bone formation.

Consumption of phytoestrogens affects bone health by regulating estrogen metabolism

Osteoporosis is a significant concern in bone health, and understanding its pathomechanism is crucial for developing effective prevention and treatment strategies. This article delves into the relationship between estrogen metabolism and bone mineralization, shedding light on how phytoestrogens can influence this intricate process. Estrogen, a hormone primarily associated with reproductive health, plays a pivotal role in maintaining bone density and structure. The article explores the positive effects of estrogen on bone mineralization, highlighting its importance in preventing conditions like osteoporosis. Phytoestrogens, naturally occurring compounds found in certain plant-based foods, are the focal point of the discussion. These compounds have the remarkable ability to mimic estrogen's actions in the body. The article investigates how phytoestrogens can modulate the activity of estrogen, thereby impacting bone health. Furthermore, the article explores the direct effects of phytoestrogens on bone mineralization and structure. By regulating estrogen metabolism, phytoestrogens can contribute to enhanced bone density and reduced risk of osteoporosis. Finally, the article emphasizes the role of plant-based diets as a source of phytoestrogens. By incorporating foods rich in phytoestrogens into one's diet, individuals may potentially bolster their bone health, adding a valuable dimension to the ongoing discourse on osteoporosis prevention. In conclusion, this article offers a comprehensive overview of 137 positions of literature on the intricate interplay between phytoestrogens, estrogen metabolism, and bone health, shedding light on their potential significance in preventing osteoporosis and promoting overall well-being.

N-Halaminated spermidine-containing polymeric coating enables titanium to achieve dual functions of antibacterial and osseointegration

Titanium (Ti) and its alloys have been widely employed in the treatment of orthopedics and other hard tissue diseases. However, Ti-based implants are bioinert and suffer from bacterial infections and poor osseointegration in clinical applications. Herein, we successfully modified Ti with a porous N-halaminated spermidine-containing polymeric coating (Ti-SPD-Cl) through alkali-heat treatment, surface grafting and chlorination, and it has both excellent antibacterial and osteogenic abilities to significantly enhance osseointegration. The as-obtained Ti-SPD-Cl contains abundant N-Cl groups and demonstrates effective antibacterial ability against S. aureus and E. coli. Meanwhile, due to the presence of the spermidine component and construction of a porous hydrophilic surface, Ti-SPD-Cl is also beneficial for maintaining cell membrane homeostasis and promoting cell adhesion, exhibiting good biocompatibility and osteogenic ability. The rat osteomyelitis model demonstrates that Ti-SPD-Cl can effectively suppress bacterial infection and enhance bone-implant integration. Thus, Ti-SPD-Cl shows promising clinical applicability in the prevention of orthopedic implant infections and poor osseointegration.

Favorable osteogenic activity of vericiguat doped in β-tricalcium phosphate: In vitro and in vivo studies

Recently, more and more studies have shown that guanylate cyclase, an enzyme that synthesizes cyclic guanosine monophosphate (cGMP), plays an important role in bone metabolism. Vericiguat (VIT), a novel oral soluble guanylate cyclase stimulator, directly generates cyclic guanosine monophosphate and reduce the death incidence from cardio-vascular causes or hospitalization. Recent studies have shown beneficial effects of VIT in animal models of osteoporosis, but very little is currently known about the effects of VIT on bone defects in the osteoporotic states. Therefore, in this study, β-tricalcium phosphate (β-TCP) was used as a carrier to explore the effect of local VIT administration on the repair of femoral metaphyseal bone defects in ovariectomized (OVX) rats. When MC3T3-E1 was cultured in the presence of H2H2, VIT, similar to Melatonin (MT), therapy could increase the matrix mineralization and ALP, SOD2, SIRT1, and OPG expression, reduce ROS and Mito SOX production, RANKL expression, Promote the recovery of mitochondrial membrane potential. In the OVX rat model, VIT increases the osteogenic effect of β-TCP and better results were obtained at a dose of 5 mg. Local use of VIT can inhibit increased OC, BMP2 and RUNX2 expressions in bone tissue, while decreased SOST and TRAP expressions by RT-PCR and immunohistochemistry. Thereby, VIT stimulates bone regeneration and is a promising candidate for promoting bone repair in osteoporosis.

Lactobacillus plantarum 45 activates SHP2 through inhibition of oxidative stress to regulate osteoblast and osteoclast differentiation

BACKGROUND

The purpose of this study is to observe LP45 (Lactobacillus plantarum 45) to investigate the mechanism by which LP45 attenuates oxidative stress-induced damage and regulates the osteoblast-osteoclast balance.

MATERIALS AND METHODS

The oxidative stress level and osteoblast- and osteoclast-related proteins were detected by immunofluorescence staining, Western blotting, ROS fluorescent probe and ELISA. Osteoblast cell proliferation capacity was determined by the CCK-8 assay. X-ray observation and HE staining were used to detect the effect of LP45 on osteoporosis.

RESULTS

The expression level of SHP2 and Src was significantly increased, and the expression levels of NOX4, P22, P47, IL-1β, NLRP3, IRF3, RANK, β-catenin and INF-β were inhibited in LP45 group and LPS + LP45 group as compared to those in LPS group. Compared with that in LPS group, the concentration of SOD was increased and the concentration of MDA was decreased in LPS + LP45 group. The protein expressions of OPG, RANKL, RUNX3, RANK and β-catenin in LP45 group and LPS + LP45 group increased. The protein expressions of NF-κB, CREB and AP-1 in LP45 group and LPS + LP45 group decreased significantly. The results were also confirmed by immunofluorescence staining and ROS fluorescent probe. X-ray observation and HE staining showed that LP45 could inhibit the progression of osteoporosis.

CONCLUSION

LP45 can exert its antioxidant effect by inhibiting the production of oxidative stress to activate the SHP2 signaling pathway, thus promoting osteoblast differentiation and repressing osteoclast formation to maintain bone homeostasis and improve bone metabolism.

Association between atherosclerosis and height loss among older individuals

Atherosclerosis and height loss are each reportedly associated with cardiovascular disease. However, no studies have found an association between atherosclerosis and height loss. A retrospective study of 2435 individuals aged 60-89 years who underwent annual health check-ups was conducted. Atherosclerosis was defined as carotid intima-media thickness (CIMT) ≥ 1.1 mm. Height loss was defined as being in the highest quintile of height decrease per year, as in our previous studies. Among study participants, 555 were diagnosed as having atherosclerosis. Independent of known cardiovascular risk factors, atherosclerosis was positively associated with height loss. The adjusted odds ratio (OR) was 1.46 (95% confidence interval, 1.15, 1.83). Essentially the same associations were observed for men and women. The adjusted OR (95% CI) was 1.43 (1.01, 2.04) for men and 1.46 (1.07, 1.99) for women. Among older individuals, atherosclerosis is associated with height loss. This result can help clarify the mechanism underlying the association between height loss and cardiovascular disease.

Bone mineral density in patients with primary ovarian insufficiency: A systematic review and Meta-Analysis

INTRODUCTION

Premature menopause is a major complication of primary ovarian insufficiency (POI), and this loss is closely relates to bone mineral density (BMD). Previous research has indicated potential associations between BMD and POI. This study set out to provide the first systematic literature review and meta-analysison account of BMD content among women with POI.

METHODS

Studies including women with POI and controls were eligible from PubMed, Embase, Cochrane Library and Web of Science databases (from their inception to April 2022). Two reviewers independently evaluated study eligibility. The meta-analysis was performed using the DerSimonian and Laird random effects model.

RESULTS

Ten studies featuring 578 women with POI and 480 controls were selected. BMD content of femur neck (SMD:-0.76; 95 % CI: -1.20 to -0.31; P = 0.0008), the BMD content of nondominating forearm (SMD:-0.67; 95 % CI: -1.15 to -0.18; P = 0.007) were significantly decreased in women with POI. However, no differences were seen in other regions (lumbar spine, total hip, hipneck).

DISCUSSION

The results of this study indicate that BMD content altered in patients with primary ovarian insufficiency. An implication of this is the possibility that hormone replacement therapy to minimize the prevalence of fracture morbidity and mortality associated with osteopenia in patients with POI.

Green space, genetic susceptibility, and risk of osteoporosis:a cohort study from the UK Biobank

OBJECTIVE

This study aimed to investigate the effect of residential exposure to green space on the incident osteoporosis and further explore the modification effect of genetic susceptibility.

METHODS

Participants from the UK Biobank were followed from 2006 to 2010 (baseline) to December 31st, 2022. Using land use coverage, we evaluated exposure to residential surrounding green space, natural environment, and domestic gardens. We used the Cox regression to examine the association between the residential environment and incident osteoporosis. The interactive effects between polygenic risk score (PRS) of osteoporosis and residential environments on incident osteoporosis were investigated.

RESULTS

This study included 292,662 participants. Over a median follow-up period of 13.65 years, we documented 9177 incidents of osteoporosis. Per interquartile (IQR) increase in greenness and natural environment at a 300 m buffer was associated with a 4% lower risk of incident osteoporosis [HR = 0.96 (95% CI: 0.93, 0.99)] and [HR = 0.96 (95% CI: 0.93, 0.98)], respectively. We did not identify any interactive effects between genetic risk and residential environment on incident osteoporosis.

CONCLUSIONS

This study found that public greenness and natural environments could reduce the risk of incident osteoporosis regardless of genetic predisposition. Developing sustainable and publicly accessible natural environments might benefit populations' bone health.

Joint effects between cadmium exposure and dietary antioxidant quality score on osteoporosis and bone mineral density

To explore the relationship between dietary antioxidant quality score (DAQS) and Cd exposure both alone and in combination with osteoporosis and bone mineral density (BMD) among postmenopausal women. In total, 4920 postmenopausal women from the National Health and Nutrition Examination Survey were included in this cross-sectional study. Weighted univariate and multivariate logistic regression analyses to assess the association between DAQS and Cd exposure with femur neck BMD, total femur BMD, osteoporosis among postmenopausal women, respectively, and the coexistence effect of DAQS and Cd exposure. Four hundred and ninety-nine had osteoporosis. DAQS (OR = 0·86, 95 % CI 0·77, 0·97) and high DAQS (OR = 0·60, 95 % CI 0·36, 0·99) were found to be associated with decreased odds of osteoporosis, while Cd exposure (OR = 1·34, 95 % CI 1·04, 1·72) and high Cd exposure (OR = 1·45, 95 % CI 1·02, 2·06) were related to increased odds of osteoporosis. A positive correlation was observed between high DAQS and both total femur BMD and femur neck BMD. Conversely, Cd exposure was found to be negatively correlated with total femur BMD and femur neck BMD. Additionally, taking low-Cd and high-quality DAQS group as reference, the joint effect of Cd exposure and DAQS showed greater increased odds of osteoporosis and decreased total femur BMD and femur neck BMD as Cd level and DAQS combinations worsened. There may be an interaction between Cd exposure and DAQS for femur neck BMD, total femur BMD, and osteoporosis in postmenopausal women.

Targeting mitochondrial dysfunction using methylene blue or mitoquinone to improve skeletal aging

Methylene blue (MB) is a well-established antioxidant that has been shown to improve mitochondrial function in both in vitro and in vivo settings. Mitoquinone (MitoQ) is a selective antioxidant that specifically targets mitochondria and effectively reduces the accumulation of reactive oxygen species. To investigate the effect of long-term administration of MB on skeletal morphology, we administered MB to aged (18 months old) female C57BL/J6 mice, as well as to adult male and female mice with a genetically diverse background (UM-HET3). Additionally, we used MitoQ as an alternative approach to target mitochondrial oxidative stress during aging in adult female and male UM-HET3 mice. Although we observed some beneficial effects of MB and MitoQ in vitro, the administration of these compounds in vivo did not alter the progression of age-induced bone loss. Specifically, treating 18-month-old female mice with MB for 6 or 12 months did not have an effect on age-related bone loss. Similarly, long-term treatment with MB from 7 to 22 months or with MitoQ from 4 to 22 months of age did not affect the morphology of cortical bone at the mid-diaphysis of the femur, trabecular bone at the distal-metaphysis of the femur, or trabecular bone at the lumbar vertebra-5 in UM-HET3 mice. Based on our findings, it appears that long-term treatment with MB or MitoQ alone, as a means to reduce skeletal oxidative stress, is insufficient to inhibit age-associated bone loss. This supports the notion that interventions solely with antioxidants may not provide adequate protection against skeletal aging.

Identification and immunological role of cuproptosis in osteoporosis

Background

osteoporosis is a skeletal disorder disease features low bone mass and poor bone architecture, which predisposes to increased risk of fracture. Copper death is a newly recognized form of cell death caused by excess copper ions, which presumably involve in various disease. Accordingly, we intended to investigate the molecular clusters related to the cuproptosis in osteoporosis and to construct a predictive model.

Methods

we investigated the expression patterns of cuproptosis regulators and immune signatures in osteoporosis based on the GSE56815 dataset. Through analysis of 40 osteoporosis samples, we investigated molecular clustering on the basis of cuproptosis--related genes, together with the associated immune cell infiltration. The WGCNA algorithm was applied to detect cluster-specific differentially expressed genes. Afterwards, the optimum machine model was selected by calculating the performance of the support vector machine model, random forest model, eXtreme Gradient Boosting and generalized linear model. Nomogram, decision curve analysis, calibration curves, and the GSE7158 dataset was utilizing to confirm the prediction efficiency.

Results

Differences between osteoporotic and non-osteoporotic controls confirm poorly adjusted copper death-related genes and triggered immune responses. In osteoporosis, two clusters of molecules in connection with copper death proliferation were outlined. The assessed levels of immune infiltration showed prominent heterogeneity between the different clusters. Cluster 2 was characterized by a raised immune score accompanied with relatively high levels of immune infiltration. The functional analysis we performed showed a close relationship between the different immune responses and specific differentially expressed genes in cluster 2. The random forest machine model showed the optimum discriminatory performance due to relatively low residuals and root mean square errors. Finally, a random forest model based on 5 genes was built, showing acceptable performance in an external validation dataset (AUC = 0.750). Calibration curve, Nomogram, and decision curve analyses also evinced fidelity in predicting subtypes of osteoporosis.

Conclusion

Our study identifies the role of cuproptosis in OP and essentially illustrates the underlying molecular mechanisms that lead to OP heterogeneity.

Fibroblast growth factor 7 protects osteoblasts against oxidative damage through targeting mitochondria

The pathophysiology of osteoporosis is significantly influenced by the impaired functioning of osteoblasts, which is particularly caused by oxidative stress. Nevertheless, the underlying mechanisms responsible for this phenomenon are still not well understood. The objective of this study was to elucidate the impact of fibroblast growth factor 7 (FGF7) on the behavior of osteoblasts under conditions of oxidative stress. The osteoblast-like MC3T3 cells were pretreated with recombinant FGF7 in the presence of oxidative stress induced by hydrogen peroxide (H2 O2 ). We first provided the evidence that the endogenous FGF7 was significantly increased in osteoblasts in response to the increased H2 O2 levels. Recombined FGF7 demonstrated a remarkable capacity to resist the detrimental effects of H2 O2 -induced oxidative stress, including the increase in cell apoptosis, decrease in osteoblast viability, and impairment in osteogenic differentiation capacity, on osteoblasts. Furthermore, we extensively explored the mechanism underlying these protective effects and discovered a remarkable modulation of reactive oxygen species (ROS) homeostasis in H2 O2 -treated cells following the pronounced expression of FGF7, which significantly differed from the control group. Additionally, we observed that FGF7 exerted partial preservation on both the morphology and function of mitochondria when exposed to oxidative stress conditions. Furthermore, FGF7 exhibited the ability to enhance the activation of the p38/MAPK signaling pathway while concurrently suppressing the JNK/MAPK signaling pathway in response to oxidative stress. These results underscore the promising role and underlying mechanisms of FGF7 in preserving osteoblast homeostasis in the face of oxidative stress.

Long-term Musculoskeletal Consequences of Chemotherapy in Pediatric Mice

Thanks to recent progress in cancer research, most children treated for cancer survive into adulthood. Nevertheless, the long-term consequences of anticancer agents are understudied, especially in the pediatric population. We and others have shown that routinely administered chemotherapeutics drive musculoskeletal alterations, which contribute to increased treatment-related toxicity and long-term morbidity. Yet, the nature and scope of these enduring musculoskeletal defects following anticancer treatments and whether they can potentially impact growth and quality of life in young individuals remain to be elucidated. Here, we aimed at investigating the persistent musculoskeletal consequences of chemotherapy in young (pediatric) mice. Four-week-old male mice were administered a combination of 5-FU, leucovorin, irinotecan (a.k.a., Folfiri) or the vehicle for up to 5 wk. At time of sacrifice, skeletal muscle, bones, and other tissues were collected, processed, and stored for further analyses. In another set of experiments, chemotherapy-treated mice were monitored for up to 4 wk after cessation of treatment. Overall, the growth rate was significantly slower in the chemotherapy-treated animals, resulting in diminished lean and fat mass, as well as significantly smaller skeletal muscles. Interestingly, 4 wk after cessation of the treatment, the animals exposed to chemotherapy showed persistent musculoskeletal defects, including muscle innervation deficits and abnormal mitochondrial homeostasis. Altogether, our data support that anticancer treatments may lead to long-lasting musculoskeletal complications in actively growing pediatric mice and support the need for further studies to determine the mechanisms responsible for these complications, so that new therapies to prevent or diminish chemotherapy-related toxicities can be identified.

Autophagy markers are decreased in bone of osteoporotic patients: a monocentric comparative study

BACKGROUND

Osteoporosis (OP) is a pathology characterized by bone fragility affecting 30% of postmenopausal women, mainly due to estrogen deprivation and increased oxidative stress. An autophagy involvement is suspected in OP pathogenesis but a definitive proof in humans remains to be obtained.

METHODS

Postmenopausal women hospitalized for femoral neck fracture (OP group) or total hip replacement (Control group) were enrolled using very strict exclusion criteria. Western blot was used to analyze autophagy level.

RESULTS

The protein expression level of the autophagosome marker LC3-II was significantly decreased in bone of OP patients relative to the control group. In addition, the protein expression of the hormonally upregulated neu-associated kinase (HUNK), which is upregulated by female hormones and promotes autophagy, was also significantly reduced in bone of the OP group.

CONCLUSIONS

These results demonstrate for the first time that postmenopausal OP patients have a deficit in bone autophagy level and suggest that HUNK could be the factor linking estrogen loss and autophagy decline.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT03175874, 2/6/2017.

Reduction of the trans-cortical vessel was associated with bone loss, another underlying mechanism of osteoporosis

RATIONALE

Numerous studies have established a robust association between bone morrow microvascular diseases and osteoporosis. This study sought to investigate the relationship between alterations in trans-cortical vessel (TCVs) and the onset of osteoporosis in various mouse models.

METHODS

Aged mice, ovariectomized mice, and db/db mice, were utilized as osteoporosis models. TCVs in the tibia were detected using tissue clearing and light sheet fluorescence microscopy imaging. Femurs bone mass were analyzed using micro-CT scanning. Correlations between the number of TCVs and bone mass were analyzed using Pearson correlation analysis.

RESULTS

All osteoporosis mouse models showed a significant reduction in the number of TCVs compared to the control group. Correlation analysis revealed a positive association between the number of TCVs and bone mass. TCVs were also expressed high levels of CD31 and EMCN proteins as type H vessels.

CONCLUSIONS

This study underscores a consistent correlation between the number of TCVs and bone mass. Moreover, TCVs may serve as a potential biomarker for bone mass evaluation.

Dexamethasone Induced Osteocyte Apoptosis in Steroid-Induced Femoral Head Osteonecrosis through ROS-Mediated Oxidative Stress

OBJECTIVE

Glucocorticoid (GC) overuse is strongly associated with steroid-induced osteonecrosis of the femoral head (SINFH). However, the underlying mechanism of SINFH remains unclear. This study aims to investigate the effect of dexamethasone (Dex)-induced oxidative stress on osteocyte apoptosis and the underlying mechanisms.

METHODS

Ten patients with SINFH and 10 patients with developmental dysplasia of the hips (DDH) were enrolled in our study. Sixty rats were randomly assigned to the Control, Dex, Dex + N-Acetyl-L-cysteine (NAC), Dex + Dibenziodolium chloride (DPI), NAC, and DPI groups. Magnetic resonance imaging (MRI) was used to examine edema in the femoral head of rats. Histopathological staining was performed to assess osteonecrosis. Immunofluorescence staining with TUNEL and 8-OHdG was conducted to evaluate osteocyte apoptosis and oxidative damage. Immunohistochemical staining was carried out to detect the expression of NOX1, NOX2, and NOX4. Viability and apoptosis of MLO-Y4 cells were measured using the CCK-8 assay and TUNEL staining. 8-OHdG staining was conducted to detect oxidative stress. 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) staining was performed to measure reactive oxygen species (ROS). The expression of NOX1, NOX2, and NOX4 in MLO-Y4 cells was analyzed by Western blotting. Multiple comparisons were performed using one-way analysis of variance (ANOVA).

RESULTS

In patients and the rat model, hematoxylin-eosin (HE) staining revealed a significantly higher rate of empty lacunae in the SINFH group than in the DDH group. Immunofluorescence staining indicated a significant increase in TUNEL-positive cells and 8-OHdG-positive cells in the SINFH group compared to the DDH group. Immunohistochemical staining demonstrated a significant increase in the expression of NOX1, NOX2, and NOX4 proteins in SINFH patients compared to DDH patients. Moreover, immunohistochemical staining showed a significant increase in the proportion of NOX2-positive cells compared to the Control group in the femoral head of rats. In vitro, Dex significantly inhibited the viability of osteocyte cells and induced apoptosis. After Dex treatment, the intracellular ROS level increased. However, Dex treatment did not alter the expression of NOX proteins in vitro. Additionally, NAC and DPI inhibited the generation of intracellular ROS and partially alleviated osteocyte apoptosis in vivo and in vitro.

CONCLUSION

This study demonstrates that GC promotes apoptosis of osteocyte cells through ROS-induced oxidative stress. Furthermore, we found that the increased expression of NOXs induced by GC serves as an important source of ROS generation.

Chromium Picolinate Regulates Bone Metabolism and Prevents Bone Loss in Diabetic Rats

Diabetic osteoporosis (DOP) is an abnormal metabolic disease caused by long-term hyperglycemia. In this study, a model rat of streptozotocin (STZ)-induced diabetes was established, and chromium picolinate (5 mg·kg-1) was given; the changes in blood glucose and body weight were detected before and after administration; and bone mineral density (BMD), bone morphology, bone turnover markers, inflammatory cytokines, and oxidative stress indicators were observed in each group. We found that after chromium picolinate (CP) intervention for 8 weeks, the blood glucose level was decreased; the BMD, the bone histomorphology parameters, and the pathological structure were improved; the expression of bone resorption-related proteins was downregulated; and the expression of bone formation-related proteins was upregulated. Meanwhile, serum antioxidant activity was increased, and inflammatory cytokine levels were decreased. In conclusion, CP could alleviate DOP by anti-oxidation, inhibition of bone turnover, anti-inflammation, and regulation of the OPG/RANKL/RANK signaling pathway. Therefore, CP has important application values for further development as a functional food or active medicine in DOP treatment.

Garcinol prevents oxidative stress-induced bone loss and dysfunction of BMSCs through NRF2-antioxidant signaling

There are multiple published data showing that excessive oxidative stress contributes to bone loss and even bone tissue damage, and it is also correlated with the pathophysiology of bone degenerative diseases, including osteoporosis (OP). Garcinol, a polyisoprenylated benzophenone derivative, has been recently established as an anti-oxidant agent. However, it remains elusive whether Garcinol protects bone marrow mesenchymal stem cells (BMSCs) and bone tissue from oxidative stress-induced damage. Here, we explored the potential effects of Garcinol supplementation in ameliorating oxidative stimulation-induced dysfunction of BMSCs and bone loss in osteoporotic mice. In this study, we verified that Garcinol exerted potent protective functions in the hydrogen peroxide (H2O2)-induced excessive oxidative stress and dysfunction of BMSCs. Besides, Garcinol was also identified to improve the reduced bone mass and abnormal lineage commitment of BMSCs in the condition of OP by suppressing the oxidative stimulation. Subsequent analysis revealed that nuclear factor erythroid 2-related factor 2 (NRF2) might be a key regulator in the sheltering effects of Garcinol on the H2O2-regulated oxidative stress, and the protective functions of Garcinol was mediated by NRF2-antioxidant signaling. Collectively, Garcinol prevented oxidative stress-related BMSC damage and bone loss through the NRF2-antioxidant signaling, which suggested the promising therapeutic values of Garcinol in the treatment of oxidative stress-related bone loss. Therefore, Garcinol might contribute to treating OP.

From the Mind to the Spine: The Intersecting World of Alzheimer's and Osteoporosis

PURPOSE OF REVIEW

This comprehensive review delves into the intricate interplay between Alzheimer's disease (AD) and osteoporosis, two prevalent conditions with significant implications for individuals' quality of life. The purpose is to explore their bidirectional association, underpinned by common pathological processes such as aging, genetic factors, inflammation, and estrogen deficiency.

RECENT FINDINGS

Recent advances have shown promise in treating both Alzheimer's disease (AD) and osteoporosis by targeting disease-specific proteins and bone metabolism regulators. Monoclonal antibodies against beta-amyloid and tau for AD, as well as RANKL and sclerostin for osteoporosis, have displayed therapeutic potential. Additionally, ongoing research has identified neuroinflammatory genes shared between AD and osteoporosis, offering insight into the interconnected inflammatory mechanisms. This knowledge opens avenues for innovative dual-purpose therapies that could address both conditions, potentially revolutionizing treatment approaches for AD and osteoporosis simultaneously. This review underscores the potential for groundbreaking advancements in early diagnosis and treatment by unraveling the intricate connection between AD and bone health. It advocates for a holistic, patient-centered approach to medical care that considers both cognitive and bone health, ultimately aiming to enhance the overall well-being of individuals affected by these conditions. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

Mind the Gap: Unraveling the Intricate Dance Between Alzheimer's Disease and Related Dementias and Bone Health

PURPOSE OF REVIEW

This review examines the linked pathophysiology of Alzheimer's disease/related dementia (AD/ADRD) and bone disorders like osteoporosis. The emphasis is on "inflammaging"-a low-level inflammation common to both, and its implications in an aging population.

RECENT FINDINGS

Aging intensifies both ADRD and bone deterioration. Notably, ADRD patients have a heightened fracture risk, impacting morbidity and mortality, though it is uncertain if fractures worsen ADRD. Therapeutically, agents targeting inflammation pathways, especially Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and TNF-α, appear beneficial for both conditions. Additionally, treatments like Sirtuin 1 (SIRT-1), known for anti-inflammatory and neuroprotective properties, are gaining attention. The interconnectedness of AD/ADRD and bone health necessitates a unified treatment approach. By addressing shared mechanisms, we can potentially transform therapeutic strategies, enriching our understanding and refining care in our aging society. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

Vialinin A alleviates oxidative stress and neuronal injuries after ischaemic stroke by accelerating Keap1 degradation through inhibiting USP4-mediated deubiquitination

BACKGROUND

Oxidative stress is known as a hallmark of cerebral ischaemia‒reperfusion injury and it exacerbates the pathologic progression of ischaemic brain damage. Vialinin A, derived from a Chinese edible mushroom, possesses multiple pharmacological activities in cancer, Kawasaki disease, asthma and pathological scarring. Notably, vialinin A is an inhibitor of ubiquitin-specific peptidase 4 (USP4) that shows anti-inflammatory and antioxidative properties. However, the precise effect of vialinin A in ischaemic stroke, as well as its underlying mechanisms, remains largely unexplored.

PURPOSE

The present research focuses on the impacts of vialinin A on oxidative stress and explores the underlying mechanisms involved while also examining its potentiality as a therapeutic candidate for ischaemic stroke.

METHODS

Mouse ischaemic stroke was conducted by MCAO surgery. Vialinin A was administered via lateral ventricular injection at a dose of 2 mg/kg after reperfusion. Subsequent experiments were meticulously conducted at the appropriate time points. Stroke outcomes were evaluated by TTC staining, neurological score, Nissl staining and behavioural analysis. Co-IP assays were operated to examine the protein-protein interactions. Immunoblot analysis, qRT-PCR, and luciferase reporter assays were conducted to further investigate its underlying mechanisms.

RESULTS

In this study, we initially showed that administration of vialinin A alleviated cerebral ischaemia‒reperfusion injury-induced neurological deficits and neuronal apoptosis. Furthermore, vialinin A, which is an antioxidant, reduced oxidative stress injury, promoted the activation of the Keap1-Nrf2-ARE signaling pathway and increased the protein degradation of Keap1. The substantial neuroprotective effects of vialinin A against ischaemic stroke were compromised by the overexpression of USP4. Mechanistically, vialinin A inhibited the deubiquitinating enzymatic activity of USP4, leading to enhanced ubiquitination of Keap1 and subsequently promoting its degradation. This cascade caused the activation of Nrf2-dependent antioxidant response, culminating in a reduction of neuronal apoptosis and the amelioration of neurological dysfunction following ischaemic stroke.

CONCLUSIONS

This study demonstrates that inhibition of USP4 to activate Keap1-Nrf2-ARE signaling pathway may represent a mechanism by which vialinin A conferred protection against cerebral ischaemia‒reperfusion injury and sheds light on its promising prospects as a therapeutic intervention for ischaemic stroke.

Pharmacological and mechanistic aspects of quercetin in osteoporosis

Osteoporosis (OP) is a bone disease associated with increasing age. Currently, the most common medications used to treat OP are anabolic agents, anti-resorptive agents, and medications with other mechanisms of action. However, many of these medications have unfavorable adverse effects or are not intended for long-term use, potentially exerting a severe negative impact on a patient's life and career and placing a heavy burden on families and society. There is an urgent need to find new drugs that can replace these and have fewer adverse effects. Quercetin (Que) is a common flavonol in nature. Numerous studies have examined the therapeutic applications of Que. However, a comprehensive review of the anti-osteoporotic effects of Que has not yet been conducted. This review aimed to describe the recent studies on the anti-osteoporotic effects of Que, including its biological, pharmacological, pharmacokinetic, and toxicological properties. The outcomes demonstrated that Que could enhance OP by increasing osteoblast differentiation and activity and reducing osteoclast differentiation and activity via the pathways of Wnt/β-catenin, BMP/SMAD/RUNX2, OPG/RANKL/RANK, ERK/JNK, oxidative stress, apoptosis, and transcription factors. Thus, Que is a promising novel drug for the treatment of OP.

Mind Gaps and Bone Snaps: Exploring the Connection Between Alzheimer's Disease and Osteoporosis

PURPOSE OF REVIEW

This comprehensive review discusses the complex relationship between Alzheimer's disease (AD) and osteoporosis, two conditions that are prevalent in the aging population and result in adverse complications on quality of life. The purpose of this review is to succinctly elucidate the many commonalities between the two conditions, including shared pathways, inflammatory and oxidative mechanisms, and hormonal deficiencies.

RECENT FINDINGS

AD and osteoporosis share many aspects of their respective disease-defining pathophysiology. These commonalities include amyloid beta deposition, the Wnt/β-catenin signaling pathway, and estrogen deficiency. The shared mechanisms and risk factors associated with AD and osteoporosis result in a large percentage of patients that develop both diseases. Previous literature has established that the progression of AD increases the risk of sustaining a fracture. Recent findings demonstrate that the reverse may also be true, suggesting that a fracture early in the life course can predispose one to developing AD due to the activation of these shared mechanisms. The discovery of these commonalities further guides the development of novel therapeutics in which both conditions are targeted. This detailed review delves into the commonalities between AD and osteoporosis to uncover the shared players that bring these two seemingly unrelated conditions together. The discussion throughout this review ultimately posits that the occurrence of fractures and the mechanism behind fracture healing can predispose one to developing AD later on in life, similar to how AD patients are at an increased risk of developing fractures. By focusing on the shared mechanisms between AD and osteoporosis, one can better understand the conditions individually and as a unit, thus informing therapeutic approaches and further research. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

Efficacy and Possible Mechanisms of Astragali Radix and its Ingredients in Animal Models of Osteoporosis: A Preclinical Review and Metaanalysis

BACKGROUND

Astragali Radix (AR) has a long history as a traditional Chinese medicine for anti-osteoporosis (OP) treatment. The aim of the study was to explore the effect and optimal regimens of AR and its main ingredients (IAR) in OP treatment.

METHODS

Eligible animal studies were searched in seven databases (PubMed, Web of Science, MEDLINE, SciELO Citation Index, Cochrane Library, China National Knowledge Infrastructure and Wanfang). The primary outcomes were bone metabolic indices. The secondary outcome measure was the anti-OP mechanism of IAR.

RESULTS

21 studies were enrolled in the study. The primary findings of the present article illustrated that IAR could significantly increase the bone mineral density (BMD), bone volume over the total volume, trabecular number, trabecular thickness, bone maximum load and serum calcium, while trabecular separation and serum C-terminal telopeptide of type 1 collagen were remarkably decreased (P < 0.05). In subgroup analysis, the BMD in the long treatment group (≥ 10 weeks) showed better effect size than the short treatment group (< 10 weeks) (P < 0.05). Modeling methods and animal sex were factors affecting serum alkaline phosphatase and osteocalcin levels.

CONCLUSION

The findings suggest the possibility of developing IAR as a drug for the treatment of OP. IAR with longer treatment time may achieve better effects regardless of animal strain and age.

Polyphenols as potential preventers of osteoporosis: A comprehensive review on antioxidant and anti-inflammatory effects, molecular mechanisms, and signal pathways in bone metabolism

Osteoporosis (OP) is a skeletal disorder characterized by decreased bone density, alterations in bone microstructure, and increased damage to the bones. As the population ages and life expectancy increases, OP has become a global epidemic, drawing attention from scientists and doctors. Because of polyphenols have favorable antioxidant and anti-allergy effects, which are regarded as potential methods to prevent angiocardipathy and OP. Polyphenols offer a promising approach to preventing and treating OP by affecting bone metabolism, reducing bone resolution, maintaining bone density, and lowering the differentiation level of osteoclasts (OC). There are multiple ways in which polyphenols affect bone metabolism. This article provides an overview of how polyphenols inhibit oxidative stress, exert antibacterial effects, and prevent the occurrence of OP. Furthermore, we will explore the regulatory mechanisms and signaling pathways implicated in this process.

Association between monocyte to high-density lipoprotein-cholesterol ratio and osteoporosis: An analysis of the National Health and Nutrition Examination Survey 2013-2014

The monocyte to high-density lipoprotein-cholesterol (HDL-C) ratio (monocyte-to-HDL-C ratio) was proposed as a marker of atherosclerosis. Osteoporosis and atherosclerosis share common risk factors and pathophysiological mechanisms. This study aimed to assess the relationship between monocyte-to-HDL-C ratio and osteoporosis. Participants aged ≥50 years with complete bone mineral density (BMD), monocyte, and HDL-C examination data from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 were included. Descriptive analysis was performed separately according to males and females. Weight linear regression and weight logistic regression analyses were used to analyze the association between the monocyte-to-HDL-C ratio and BMD and osteopenia and osteoporosis and vertebral fracture. A total of 1804 participants were included. Among the participants with osteopenia, 398 (48.31%) were males and 466 (51.91%) were females. Among those with osteoporosis, 38 (2.77%) were males and 95 (9.50%) were females. In females, monocyte-to-HDL-C ratio was negatively associated with femoral neck BMD (regression coefficient (β) = -0.18; 95% confidence interval (CI): (-0.29, -0.07)) and high monocyte-to-HDL-C ratio was associated with higher odds of osteopenia (odds ratio (OR) = 1.22; 95% CI: (1.01, 1.47)) and osteoporosis (OR = 1.68; 95% CI: (1.13, 2.49)) after adjusting for confounders. In males, only monocyte-to-HDL-C ratio >0.35 was observed to be associated with higher odds of osteoporosis (OR = 1.96; 95% CI: (1.02, 3.79)). Stratified analyses showed that similar results were also found in different populations. This study showed that the monocyte-to-HDL-C ratio was negatively associated with BMD and the risk of osteopenia and osteoporosis in females. The monocyte-to-HDL-C ratio may be a new marker of osteoporosis or osteopenia.

Trichostatin A enhances the titanium rods osseointegration in osteoporotic rats by the inhibition of oxidative stress through activating the AKT/Nrf2 pathway

The use of titanium implants as fixed supports following fractures in patients with OP can often result in sterile loosening and poor osseointegration. Oxidative stress has been shown to play a particularly important role in this process. While TSA has been reported to facilitate in vivo osteogenesis, the underlying mechanisms remain to be clarified. It also remains unclear whether TSA can improve the osseointegration of titanium implants. This study investigated whether TSA could enhance the osseointegration of titanium rods by activating AKT/Nrf2 pathway signaling, thereby suppressing oxidative stress. MC3T3-E1 cells treated with CCCP to induce oxidative stress served as an in vitro model, while an OVX-induced OP rat model was employed for in vivo analysis of titanium rod implantation. In vitro, TSA treatment of CCCP-treated MC3T3-E1 cells resulted in the upregulation of osteogenic proteins together with increased AKT, total Nrf2, nuclear Nrf2, HO-1, and NQO1 expression, enhanced mitochondrial functionality, and decreased oxidative damage. Notably, the PI3K/AKT inhibitor LY294002 reversed these effects. In vivo, TSA effectively enhanced the microstructural characteristics of distal femur trabecular bone, increased BMSCs mineralization capacity, promoted bone formation, and improved the binding of titanium implants to the surrounding tissue. Finally, our results showed that TSA could reverse oxidative stress-induced cell damage while promoting bone healing and improving titanium rods' osseointegration through AKT/Nrf2 pathway activation.

Exposure to Trihalomethanes and Bone Mineral Density in US Adolescents: A Cross-Sectional Study (NHANES)

Animal and human studies have suggested that trihalomethane (THM) has toxicity to bone. In this study, we included adolescents from the National Health and Nutrition Examination Survey who had quantified blood and tap water THM concentrations [chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)] and lumbar spine or total body less head (TBLH) bone mineral density (BMD). A 2.7-fold increase in concentrations of blood TCM, DBCM, chlorinated THMs (the sum of TCM, BDCM, and DBCM), and total THMs (the sum of 4 THMs) was associated with lower lumbar spine BMD z-scores by -0.06 [95% confidence interval (CI): -0.12, -0.01], -0.06 (95% CI: -0.11, -0.003), -0.08 (95% CI: -0.14, -0.02), and -0.07 (95% CI: -0.13, -0.003), respectively, in adjusted models. Similarly, a 2.7-fold increase in blood BDCM, DBCM, and chlorinated THM concentrations was associated with lower TBLH BMD z-scores by -0.10 (95% CI: -0.17, -0.02), -0.10 (95% CI: -0.17, -0.03), and -0.11 (95% CI: -0.20, -0.01), respectively. Low-to-moderate predictive power was attained when tap water THM concentrations were used to predict blood THM measurements. Notably, the inverse associations for blood THMs persisted exclusively between water concentrations of DBCM and Br-THMs and the TBLH BMD z-scores. Our findings suggest that exposure to THMs may adversely affect the adolescent BMD.

Bone mineral density is associated with composite dietary antioxidant index among US adults: results from NHANES

This cross-sectional study investigated the relationship between composite dietary antioxidant index (CDAI) and individual dietary antioxidant intakes, including vitamins A, C, and E, zinc, selenium, and carotenoids, and bone mineral density (BMD) in the US population aged 20 years older. We found a positive correlation between CDAI and femoral BMD. Moreover, higher intakes of vitamin C, vitamin E, selenium, zinc, and carotenoids were associated with higher femoral BMD.

INTRODUCTION

While individual dietary antioxidants have shown beneficial effects on bone metabolism, the diverse and potentially interacting nature of dietary components may limit the accuracy of evaluating their impact on bone health. Thus, this study aims to investigate the association between CDAI and BMD. Additionally, we explore the relationship between the intake of individual components of the CDAI and BMD.

METHODS

The CDAI is a novel index evaluating total dietary antioxidant intake, considering vitamins A, C, and E, zinc, selenium, and carotenoids. A cross-sectional analysis was conducted using data from participants aged ≥ 20 in the National Health and Nutrition Examination Survey (2005-2010, 2013-2014, and 2017-2018). We utilized multivariate linear regression models to examine the relationship between CDAI, individual dietary antioxidants, including vitamins A, C, and E, zinc, selenium, carotenoids, and femoral BMD.

RESULTS

The final analysis included 10,584 participants with a mean age of 50.73 ± 16.65 years. After multivariate adjustment, the second to fourth quartiles of CDAI (- 2.00-0.04, 0.04-2.54, and 2.54-70.78) exhibited higher femoral BMD compared to the first quartile of CADI (- 7.34 to - 2.00). Multiple regression analysis revealed that higher intakes of vitamin C, vitamin E, selenium, zinc, and carotenoids were associated with higher femoral BMD.

CONCLUSIONS

CDAI serves as a comprehensive tool for evaluating the overall antioxidant capacity of antioxidants in diets. Additionally, our study shows a positive correlation between CDAI and BMD, which indicates that the combined intake of dietary antioxidants may help reduce the risk of osteoporosis in adults.

Associations of dietary oxidative balance score with femur osteoporosis in postmenopausal women: data from the National Health and Nutrition Examination Survey

We used data from the NHANES to explore associations of DOBS with femur BMD and osteoporosis in postmenopausal women. We found that DOBS was positively associated with femur BMD and negatively associated with the risk of osteoporosis in postmenopausal women.

PURPOSE

The study aimed to investigate the relationship between dietary oxidative balance score (DOBS) and the risk of osteoporosis in American postmenopausal women.

METHODS

A total of 3043 participants were included in this study. The linear relationship between DOBS and femur BMD was evaluated using a weighted multivariate linear regression model. The association between DOBS and the risk of osteoporosis was assessed using a weighted logistic regression model, with odds ratios (ORs) and 95% confidence intervals (CIs) calculated. Moreover, the relationship was further characterized through smooth curve fitting (SCF) and weighted generalized additive model (GAM) analysis.

RESULTS

After adjusting for all covariates, the weighted multivariable linear regression models showed a positive correlation between DOBS and femur BMD. Moreover, the weighted logistic regression model demonstrated that compared to the first tertile of DOBS, the highest tertile of DOBS was significantly associated with a lower risk of osteoporosis, with ORs of 0.418 (95% CI, 0.334, 0.522) for individuals under the age of 70 and 0.632 (95% CI, 0.506, 0.790) for individuals aged 70 or above. Similar trends were also observed in SCF and GAM models.

CONCLUSION

The present study indicated that postmenopausal women with a higher DOBS have a lower risk of femur osteoporosis. This finding may highlight the potential protective role of an antioxidant-rich diet for the bones of the postmenopausal population. Moreover, DOBS may also be a valuable tool in identifying individuals with osteoporosis. Screening and early intervention for osteoporosis may be essential for postmenopausal women with low DOBS.

Catalpol ameliorates dexamethasone-induced osteoporosis by promoting osteogenic differentiation of bone marrow mesenchymal stem cells via the activation of PKD1 promoter

OBJECTIVE

To investigate the effects of CA on glucocorticoid-induced osteoporosis (GIOP) and lucubrate the underlying mechanism of CA via the activation of polycystic kidney disease-1(PKD1) in bone marrow mesenchymal stem cells (BMSCs).

METHODS

In vivo, a GIOP model in mice treated with dexamethasone (Dex) was established. Biomechanical, micro-CT, immunofluorescence staining of OCN, ALP and PKD1 and others were severally determined. qRT-PCR and Western blot methods were adopted to elucidate the particular mechanisms of CA on GIOP. In addition, BMSCs cultured in vitro were also induced by Dex to verify the effects of CA. Finally, siRNA and luciferase activity assays were performed to confirm the mechanisms.

RESULTS

We found that CA could restore the destroyed bone microarchitecture and increase the bone mass in GIOP mice. CA could also upregulate PKD1 protein expression, reduce oxidative stress, and promote mRNA expression of bone formation-associated markers in GIOP mice. Furthermore, it was also observed that CA reduced oxidative stress and promoted osteogenic differentiation in Dex-induced BMSCs. Mechanically, CA could promote protein expression via increasing the activity of PKD1 promoter.

CONCLUSION

This study provides important evidences for CA in the further clinical treatment of GIOP, reveals the activation of PKD1 promoter as the underlying mechanism.

Tussilagone inhibits osteoclastogenesis by modulating mitochondrial function and ROS production involved Nrf2 activation

Reactive Oxygen Species (ROS) play an essential role in the pathogenesis of osteoporosis mainly characterized by excessive osteoclasts (OCs) activity. OCs are rich in mitochondria for energy support, which is a major source of total ROS. Tussilagone (TSG), a natural Sesquiterpenes from the flower of Tussilago farfara, has plentiful beneficial pharmacological characteristics with anti-inflammatory and anti-oxidative activity, but its effects and mechanism in osteopathology are still unclear. In our study, we investigated the regulation of ROS generated from the mitochondria in OCs. We found that TSG inhibited OCs differentiation and bone resorption without any cytotoxicity. Mechanistically, TSG reduced RANKL-mediated total ROS level by down-regulating intracellular ROS production and mitochondrial function, leading to the suppression of NFATc1 transcription. We also found that nuclear factor erythroid 2-related factor 2 (Nrf2) could enhance ROS scavenging enzymes in response to RANKL-induced oxidative stress. Furthermore, TSG up-regulated the expression of Nrf2 by inhibiting its proteosomal degradation. Interestingly, Nrf2 deficiency reversed the suppressive effect of TSG on mitochondrial activity and ROS signaling in OCs. Consistent with this finding, TSG attenuated post-ovariectomy (OVX)- and lipopolysaccharide (LPS) induced bone loss by ameliorating osteoclastogenesis. Taken together, TSG has an anti-bone resorptive effect by modulating mitochondrial function and ROS production involved Nrf2 activation.

Diet-derived antioxidants and osteoporosis: A Mendelian randomization study

BACKGROUND

Antioxidants can prevent osteoporosis, but the association between serum antioxidants and the cause of osteoporosis remains unknown. We aimed to utilize Mendelian randomization (MR) to determine whether genetically predicted serum levels of diet-derived antioxidants can affect the risk of osteoporosis, to determine the effect of dietary supplementation of antioxidants.

METHODS

Genetic variants associated with diet-derived antioxidants were selected from the genome-wide association studies. A total of 12,946 osteoporosis cases and 506,624 healthy controls were obtained from UK Biobank (UKB) and Genetic Factors of Osteoporosis (GEFOS) consortia. We implemented a two-sample MR design and performed several sensitivity analyses to evaluate the causal relationship.

RESULTS

In UKB, the genetically predicted higher β-carotene (OR = 0.863, p = 7.37 × 10-6, power = 100%) and γ-tocopherol (OR = 0.701, p = 0.021, power = 5%) had an inverse relationship with osteoporosis. However, only the association of serum β-carotene passed FDR correction. In GEFOS, there were no significant diet-derived antioxidants. The direction of the association of β-carotene with osteoporosis (OR = 0.844, p = 0.106, power = 87%) was consistent with that in the UKB dataset. A fixed-effects meta-analysis confirmed that β-carotene (OR = 0.862, p = 2.21 × 10-6) and γ-tocopherol (OR = 0.701, p = 2.31 × 10-2) could decrease the risk of osteoporosis. To reduce exclusion limit bias, we used total body bone mineral density, lumbar spine bone mineral density and femoral neck bone mineral density as surrogates and found that the genetically elevated circulating β-carotene level could increase total body BMD (beta = 0.043, p-value = 8.26 x 10-5, power = 100%), lumbar spine BMD (beta = 0.226, p-value = 0.001, power = 100%) and femoral neck BMD(beta = 0.118, p-value = 0.016, power = 100%).

CONCLUSIONS

We observed that genetically predicted serum β-carotene could elevate BMD and prevent osteoporosis.

Ginsenoside compound-K attenuates OVX-induced osteoporosis via the suppression of RANKL-induced osteoclastogenesis and oxidative stress

Osteoporosis (OP), a systemic and chronic bone disease, is distinguished by low bone mass and destruction of bone microarchitecture. Ginsenoside Compound-K (CK), one of the metabolites of ginsenoside Rb1, has anti-aging, anti-inflammatory, anti-cancer, and hypolipidemic activities. We have demonstrated CK could promote osteogenesis and fracture healing in our previous study. However, the contribution of CK to osteoporosis has not been examined. In the present study, we investigated the effect of CK on osteoclastogenesis and ovariectomy (OVX)-induced osteoporosis. The results showed that CK inhibited receptor activator for nuclear factor-κB ligand (RANKL)-mediated osteoclast differentiation and reactive oxygen species (ROS) activity by inhibiting the phosphorylation of NF-κB p65 and oxidative stress in RAW264.7 cells. In addition, we also demonstrated that CK could inhibit bone resorption using bone marrow-derived macrophages. Furthermore, we demonstrated that CK attenuated bone loss by suppressing the activity of osteoclast and alleviating oxidative stress in vivo. Taken together, these results showed CK could inhibit osteoclastogenesis and prevent OVX-induced bone loss by inhibiting NF-κB signaling pathway.

The role of retinoic acid receptor-related orphan receptors in skeletal diseases

Bone homeostasis, depending on the balance between bone formation and bone resorption, is responsible for maintaining the proper structure and function of the skeletal system. As an important group of transcription factors, retinoic acid receptor-related orphan receptors (RORs) have been reported to play important roles in bone homeostasis by regulating the transcription of target genes in skeletal cells. On the other hand, the dysregulation of RORs often leads to various skeletal diseases such as osteoporosis, rheumatoid arthritis (RA), and osteoarthritis (OA). Herein, we summarized the roles and mechanisms of RORs in skeletal diseases, aiming to provide evidence for potential therapeutic strategies.

A Novel PTH-Related Peptide Combined With 3D Printed Macroporous Titanium Alloy Scaffold Enhances Osteoporotic Osseointegration

Previous parathyroid hormone (PTH)-related peptides (PTHrPs) cannot be used to prevent implant loosening in osteoporosis patients due to the catabolic effect of local sustained release. A novel PTHrP (PTHrP-2) that can be used locally to promote osseointegration of macroporous titanium alloy scaffold (mTAS) and counteract implant slippage in osteoporosis patients is designed. In vitro, PTHrP-2 enhances the proliferation, adhesion, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) within the mTAS. Further, it promotes proliferation, migration, angiogenesis-related protein expression, and angiogenesis in human umbilical vein endothelial cells (HUVECs). Compared to PTH(1-34), PTHrP-2 can partially weaken the osteoclast differentiation of RAW 264.7 cells. Even in an oxidative stress microenvironment, PTHrP-2 safeguards the proliferation and migration of BMSCs and HUVECs, reduces reactive oxygen species generation and mitochondrial damage, and partially preserves the angiogenesis of HUVECs. In the Sprague-Dawley (SD) rat osteoporosis model, the therapeutic benefits of PTHrP-2-releasing mTAS (mTASP2 ) and ordinary mTAS implanted for 12 weeks via micro-CT, sequential fluorescent labeling, and histology are compared. The results demonstrate that mTASP2 exhibits high bone growth rate, without osteophyte formation. Consequently, PTHrP-2 exhibits unique local synthesis properties and holds the potential for assisting the osseointegration of alloy implants in osteoporosis patients.

Association of urinary bisphenols with oxidative stress and inflammatory markers and their role in obesity

Bisphenol A (BPA) and its substitutes are widely used in daily life. Animal and cell line experiments have confirmed the effects of bisphenols on oxidative stress and inflammation. However, current population evidence for the effects of BPA alternatives, such as bisphenol F (BPF) and bisphenol S (BPS), on oxidative stress and inflammation is still sparse. Based on the National Health and Nutrition Examination Survey 2013-2016 data, our study used linear regression, weighted quantile sum model, and Bayesian kernel machine regression model to evaluate the effects of BPA, BPS, and BPF alone and in combination on oxidative stress (serum total bilirubin, and iron) and inflammation (alkaline phosphatase, C-reactive protein, γ-glutamyl transferase ferritin, neutrophil count, lymphocyte count, and neutrophil-to-lymphocyte ratio) markers. On this basis, the possible roles of oxidative stress and inflammation in obesity, which is associated with exposure to bisphenols (BPs), were initially explored. Based on the different covariates selected, a total of 3039 and 2258 participants were included in our study for models 1 and 2, respectively; the median age of participants was 48 years, and 48.7 % were male. Based on all models, our results showed that exposure to BPs alone or in combination was associated with downregulation of serum total bilirubin. Urinary BPF concentration was specifically associated with the neutrophil-to-lymphocyte ratio. Serum total bilirubin may play a role in the association between obesity and BP mixture exposure. Upregulation of the neutrophil-to-lymphocyte ratio was not associated with obesity. In conclusion, our study found that single or combined exposure to BPs, as measured in urine, may be associated with changes in oxidative stress and inflammatory markers, and a decrease in serum total bilirubin may play a mediating role in BP-induced obesity.

Simulated microgravity-induced oxidative stress and loss of osteogenic potential of osteoblasts can be prevented by protection of primary cilia

Oxidative stress has been considered to be closely related to spaceflight-induced bone loss; however, mechanism is elusive and there are no effective countermeasures. Using cultured rat calvarial osteoblasts exposed to microgravity simulated by a random positioning machine, this study addressed the hypotheses that microgravity-induced shortening of primary cilia leads to oxidative stress and that primary cilium protection prevents oxidative stress and osteogenesis loss. Microgravity was found to induce oxidative stress (as represented by increased levels of reactive oxygen species (ROS) and malondialdehyde production, and decreased activities of antioxidant enzymes), which was perfectly replicated in osteoblasts growing in NG with abrogated primary cilia (created by transfection of an interfering RNA), suggesting the possibility that shortening of primary cilia leads to oxidative stress. Oxidative stress was accompanied by mitochondrial dysfunction (represented by increased mitochondrial ROS and decreased mitochondrial membrane potential) and intracellular Ca2+ overload, and the latter was found to be caused by increased activity of Ca2+ channel transient receptor potential vanilloid 4 (TRPV4), as also evidenced by TRPV4 agonist GSK1016790A-elicited Ca2+ influx. Supplementation of HC-067047, a specific antagonist of TRPV4, attenuated microgravity-induced mitochondrial dysfunction, oxidative stress, and osteogenesis loss. Although TRPV4 was found localized in primary cilia and expressed at low levels in NG, microgravity-induced shortening of primary cilia led to increased TRPV4 levels and Ca2+ influx. When primary cilia were protected by miR-129-3p overexpression or supplementation with a natural flavonoid moslosooflavone, microgravity-induced increased TRPV4 expression, mitochondrial dysfunction, oxidative stress, and osteogenesis loss were all prevented. Our data revealed a new mechanism that primary cilia function as a controller for TRPV4 expression. Microgravity-induced injury on primary cilia leads to increased expression and overactive channel of TRPV4, causing intracellular Ca2+ overload and oxidative stress, and primary cilium protection could be an effective countermeasure against microgravity-induced oxidative stress and loss of osteogenic potential of osteoblasts.

The Impact of Tannic Acid Consumption on Bone Mineralization

Tannic acid (TA) is an organic compound belonging to the tannin group. Like other tannins, it has an affinity for endogenous proteins, including digestive enzymes, which can result in the reduced digestibility and absorption of nutrients. It can also form complexes with mineral components, reducing their absorption. In some cases, this can be beneficial, such as in the case of toxic metals, but sometimes it may have a detrimental effect on the body when it involves essential mineral components like Ca, P, Mg, Na, K, or Fe. Therefore, the impact of TA on bone health should be considered from both perspectives. This relatively short review summarizes the available information and research findings on TA, with a particular focus on its potential impact on bone health. It is worth noting that future research and clinical studies may provide more detailed and precise information on this topic, allowing for a better understanding of the role of TA in maintaining the integrity of the musculoskeletal system. Despite its brevity, this paper represents a valuable contribution to the analysis of the potential benefits and challenges associated with TA in the context of bone health. We anticipate that future research will continue along this important research line, expanding our knowledge of the influence of this compound on the skeletal system and its potential therapeutic applications.

Hesperidin Anti-Osteoporosis by Regulating Estrogen Signaling Pathways

Osteoporosis (OP) is distinguished by a reduction in bone mass and degradation of bone micro-structure, frequently resulting in fractures. As the geriatric demographic expands, the incidence of affected individuals progressively rises, thereby exerting a significant impact on the quality of life experienced by individuals. The flavonoid compound hesperidin has been subject to investigation regarding its effects on skeletal health, albeit the precise mechanisms through which it operates remain ambiguous. This study utilized network pharmacology to predict the core targets and signaling pathways implicated in the anti-OP properties of hesperidin. Molecular docking and molecular dynamics simulations were employed to confirm the stability of the interaction between hesperidin and the core targets. The effects of hesperidin on osteoblastic cells MC3T3-E1 were assessed using MTT, ELISA, alkaline phosphatase assay, and RT-qPCR techniques. Furthermore, in vivo experiments were conducted to determine the potential protective effects of hesperidin on zebrafish bone formation and oxidative stress response. The results demonstrate that network pharmacology has identified 10 key target points, significantly enriched in the estrogen signaling pathway. Hesperidin exhibits notable promotion of MC3T3-E1 cell proliferation and significantly enhances ALP activity. ELISA measurements indicate an elevation in NO levels and a reduction in IL-6 and TNF-α. Moreover, RT-qPCR analysis consistently reveals that hesperidin significantly modulates the mRNA levels of ESR1, SRC, AKT1, and NOS3 in MC3T3-E1 cells. Hesperidin promotes osteogenesis and reduces oxidative stress in zebrafish. Additionally, we validate the stable and tight binding of hesperidin with ESR1, SRC, AKT1, and NOS3 through molecular dynamics simulations. In conclusion, our comprehensive analysis provides evidence that hesperidin may exert its effects on alleviating OP through the activation of the estrogen signaling pathway via ESR1. This activation leads to the upregulation of SRC, AKT, and eNOS, resulting in an increase in NO levels. Furthermore, hesperidin promotes osteoblast-mediated bone formation and inhibits pro-inflammatory cytokines, thereby alleviating oxidative stress associated with OP.

The Effects of Polyphenols on Bone Metabolism in Postmenopausal Women: Systematic Review and Meta-Analysis of Randomized Control Trials

Osteoporosis is a condition favored by the postmenopausal decline in estrogen levels and worsened by oxidative stress (OS). Polyphenols are natural compounds abundantly found in fruits and vegetables, and they exert antioxidant and hormonal effects that could be useful in osteoporosis prevention, as suggested by epidemiological studies showing a lower incidence of fractures in individuals consuming polyphenol-rich diets. The aim of our meta-analysis is to evaluate the effects of polyphenols on bone mineral density (BMD, primary endpoint) and bone turnover markers (BTMs, secondary endpoint) in postmenopausal women. Twenty-one randomized control trials (RCTs) were included in our analysis after in-depth search on PubMed, EMBASE, and Scopus databases. We found that supplementation with polyphenols for 3-36 months exerted no statically significant effects on BMD measured at lumbar spine (sMD: 0.21, 95% CI [-0.08 to 0.51], p = 0.16), femoral neck (sMD: 0.16, 95% CI [-0.23 to 0.55], p = 0.42), total hip (sMD: 0.05, 95% CI [-0.14 to 0.24], p = 0.61), and whole body (sMD: -0.12, 95% CI [-0.42 to 0.17], p = 0.41). Subgroup analysis based on treatment duration showed no statistical significance, but a significant effect on lumbar BMD emerged when studies with duration of 24 months or greater were analyzed separately. On the other hand, we found a significantly slight increase in bone-specific alkaline phosphatase (BALP) levels (sMD: 1.27, 95% CI [1.13 to 1.42], p < 0.0001) and a decrease in pyridinoline (PD) levels (sMD: -0.58, 95% CI [-0.77 to -0.39], p < 0.0001). High heterogeneity among studies and unclear risk of bias in one third of the included studies emerged. A subgroup analysis showed similar effects for different duration of treatment and models of dual-energy X-ray absorptiometry (DXA) scanner. More robust evidence is needed before recommending the prescription of polyphenols in clinical practice.

The Role of Oxidative Stress in Multiple Exercise-Regulated Bone Homeostasis

Bone is a tissue that is active throughout the lifespan, and its physiological activities, such as growth, development, absorption, and formation, are always ongoing. All types of stimulation that occur in sports play an important role in regulating the physiological activities of bone. Here, we track the latest research progress locally and abroad, summarize the recent, relevant research results, and systematically summarize the effects of different types of exercise on bone mass, bone strength and bone metabolism. We found that different types of exercise have different effects on bone health due to their unique technical characteristics. Oxidative stress is an important mechanism mediating the exercise regulation of bone homeostasis. Excessive high-intensity exercise does not benefit bone health but induces a high level of oxidative stress in the body, which has a negative impact on bone tissue. Regular moderate exercise can improve the body's antioxidant defense ability, inhibit an excessive oxidative stress response, promote the positive balance of bone metabolism, delay age-related bone loss and deterioration of bone microstructures and have a prevention and treatment effect on osteoporosis caused by many factors. Based on the above findings, we provide evidence for the role of exercise in the prevention and treatment of bone diseases. This study provides a systematic basis for clinicians and professionals to reasonably formulate exercise prescriptions and provides exercise guidance for patients and the general public. This study also provides a reference for follow-up research.

Curculigoside attenuates osteoporosis through regulating DNMT1 mediated osteoblast activity

This work aims to study the function of curculigoside in osteoporosis and explore whether DNMT1 is closely involved in osteoblast activity. After OB-6 osteoblasts were treated with hydrogen peroxide (H2O2), a curculigoside treatment group was set up and a series of biological tests including MTT, flow cytometry, western blotting, ROS fluorescence intensity, mitochondrial membrane potential, and ELISA experiments were performed to verify the effect of curculigoside on the activity of osteoblasts. Then, alkaline phosphatase (ALP) activity, alizarin red staining, PCR, and western blotting assays were performed to detect the effects of curculigoside on osteoblast function. By constructing DNMT1 knockdown and overexpression OB-6 cell lines, the effect of DNMT1 on osteoblast function was verified. In addition, the expression level of Nrf2 in each group was detected to speculate the mechanism of DNMT1 in osteoporosis. The cell activity and level of bcl-2 and SOD were significantly increased; the cell apoptosis, ROS fluorescence intensity, mitochondrial membrane potential, MDA and level of caspase-3, Bax, and CAT was reduced in curculigoside treatment group compared with H2O2-induced OB-6 osteoblasts. Meanwhile, the ALP activity, number and area of bone mineralized nodules, and gene and protein expression of OSX and OPG were significantly elevated in curculigoside group. Moreover, DNMT1 knockdown had a similar promotion effect on osteoblast function as curculigoside, and DNMT1 overexpression could reverse the promotion effect of curculigoside on osteoblast function. Further mechanistic studies speculated that DNMT1 might play a role in osteoporosis by affecting Nrf2 methylation. Curculigoside enhances osteoblast activity through DNMT1 controls of Nrf2 methylation.

Sulforaphene suppresses RANKL-induced osteoclastogenesis and LPS-induced bone erosion by activating Nrf2 signaling pathway

BACKGROUND AND PURPOSE

Inflammatory disorders have been found to induce bone loss through sustained and persistent activation of osteoclast differentiation, leading to heightened bone resorption. The current pharmacological interventions for combating bone loss to harbor adverse effects or contraindications. There is a pressing need to identify drugs with fewer side effects.

EXPERIMENTAL APPROACH

The effect and underlying mechanism of sulforaphene (LFS) on osteoclast differentiation were illustrated in vitro and in vivo with RANKL-induced Raw264.7 cell line osteoclastogenesis and lipopolysaccharide (LPS)-induced bone erosion model.

KEY RESULTS

In this study, LFS has been shown to effectively impede the formation of mature osteoclasts induced from both Raw264.7 cell line and bone marrow macrophages (BMMs), mainly at the early stage. Further mechanistic investigations uncovered that LFS suppressed AKT phosphorylation. SC-79, a potent AKT activator, was found to reverse the inhibitory impact of LFS on osteoclast differentiation. Moreover, transcriptome sequencing analysis revealed that treatment with LFS led to a significant upregulation in the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant-related genes. Then it's validated that LFS could promote NRF2 expression and nuclear translocation, as well as effectively resist oxidative stress. NRF2 knockdown reversed the suppression effect of LFS on osteoclast differentiation. In vivo experiments provide convincing evidence that LFS is protective against LPS-induced inflammatory osteolysis.

CONCLUSION AND IMPLICATIONS

These well-grounded and promising findings suggest LFS as a promising agent to addressing oxidative-stress related diseases and bone loss disorders.

Ultrasound-Responsive Nanobubbles for Combined siRNA-Cerium Oxide Nanoparticle Delivery to Bone Cells

This study aims to present an ultrasound-mediated nanobubble (NB)-based gene delivery system that could potentially be applied in the future to treat bone disorders such as osteoporosis. NBs are sensitive to ultrasound (US) and serve as a controlled-released carrier to deliver a mixture of Cathepsin K (CTSK) siRNA and cerium oxide nanoparticles (CeNPs). This platform aimed to reduce bone resorption via downregulating CTSK expression in osteoclasts and enhance bone formation via the antioxidant and osteogenic properties of CeNPs. CeNPs were synthesized and characterized using transmission electron microscopy and X-ray photoelectron spectroscopy. The mixture of CTSK siRNA and CeNPs was adsorbed to the surface of NBs using a sonication method. The release profiles of CTSK siRNA and CeNPs labeled with a fluorescent tag molecule were measured after low-intensity pulsed ultrasound (LIPUS) stimulation using fluorescent spectroscopy. The maximum release of CTSK siRNA and the CeNPs for 1 mg/mL of NB-(CTSK siRNA + CeNPs) was obtained at 2.5 nM and 1 µg/mL, respectively, 3 days after LIPUS stimulation. Then, Alizarin Red Staining (ARS) was applied to human bone marrow-derived mesenchymal stem cells (hMSC) and tartrate-resistant acid phosphatase (TRAP) staining was applied to human osteoclast precursors (OCP) to evaluate osteogenic promotion and osteoclastogenic inhibition effects. A higher mineralization and a lower number of osteoclasts were quantified for NB-(CTSK siRNA + CeNPs) versus control +RANKL with ARS (p < 0.001) and TRAP-positive staining (p < 0.01). This study provides a method for the delivery of gene silencing siRNA and CeNPs using a US-sensitive NB system that could potentially be used in vivo and in the treatment of bone fractures and disorders such as osteoporosis.

The Emerging Role of the Mitochondrial Respiratory Chain in Skeletal Aging

Maintenance of mitochondrial homeostasis is crucial for ensuring healthy mitochondria and normal cellular function. This process is primarily responsible for regulating processes that include mitochondrial OXPHOS, which generates ATP, as well as mitochondrial oxidative stress, apoptosis, calcium homeostasis, and mitophagy. Bone mesenchymal stem cells express factors that aid in bone formation and vascular growth. Positive regulation of hematopoietic stem cells in the bone marrow affects the differentiation of osteoclasts. Furthermore, the metabolic regulation of cells that play fundamental roles in various regions of the bone, as well as interactions within the bone microenvironment, actively participates in regulating bone integrity and aging. The maintenance of cellular homeostasis is dependent on the regulation of intracellular organelles, thus understanding the impact of mitochondrial functional changes on overall bone metabolism is crucially important. Recent studies have revealed that mitochondrial homeostasis can lead to morphological and functional abnormalities in senescent cells, particularly in the context of bone diseases. Mitochondrial dysfunction in skeletal diseases results in abnormal metabolism of bone-associated cells and a secondary dysregulated microenvironment within bone tissue. This imbalance in the oxidative system and immune disruption in the bone microenvironment ultimately leads to bone dysplasia. In this review, we examine the latest developments in mitochondrial respiratory chain regulation and its impacts on maintenance of bone health. Specifically, we explored whether enhancing mitochondrial function can reduce the occurrence of bone cell deterioration and improve bone metabolism. These findings offer prospects for developing bone remodeling biology strategies to treat age-related degenerative diseases.

Association between dietary folate intake and bone mineral density in a diverse population: a cross-sectional study

BACKGROUND

Osteoporosis is a major public health problem, yet the association between dietary folate intake and bone health has been rarely studied. This study aimed to investigate the relationship between dietary folate intake and bone mineral density (BMD) in the general population of the USA.

METHODS

Utilizing data from the National Health and Nutrition Examination Survey, dietary folate intake was gauged through 24-h dietary recall and BMD was determined via dual-energy X-ray absorptiometry. Multivariate linear regression models and generalized additive models were employed for correlation analysis.

RESULTS

The study incorporated 9839 participants (48.88% males, aged 20-85 years, mean age: 47.62 ± 16.22). The average dietary folate intake stood at 401.1 ± 207.9 μg/day. And the average total femur, femoral neck, trochanter, intertrochanter, and lumbar BMD were 0.98 ± 0.16 g/cm2, 0.84 ± 0.15 g/cm2, 0.73 ± 0.13 g/cm2, 1.16 ± 0.19 g/cm2, and 1.03 ± 0.15 g/cm2, respectively. The higher quartiles of dietary folate intake directly correlated with increased total femoral, femoral neck, intertrochanteric, and lumbar BMD (P for trend = 0.003, 0.016, < 0.001, and 0.033, respectively). A consistent positive association between folate intake and BMD across age groups was observed, with significant findings for individuals over 80 years and non-Hispanic whites. Physical activity level and serum 25-hydroxyvitamin D levels influenced the association, with an optimal daily folate intake of 528-569 µg recommended for postmenopausal women.

CONCLUSION

In summary, our study reveals a significant positive association between dietary folate intake and BMD, across different age groups and particularly among individuals over 80 years old. Non-Hispanic whites benefit the most from increased folate intake. Physical activity level and serum 25-hydroxyvitamin D levels interact with this association. Screening and early intervention for osteoporosis may be essential for individuals with low dietary folate intake.