Astaxanthin prevents bone loss in osteoporotic rats with palmitic acid through suppressing oxidative stress

OBJECTIVES

The study aimed to assess the role of Astaxanthin (ATX) in palmitic acid(PA) -induced bone loss in Ovariectomized(OVX) rats.

METHODS

In the OVX rat model, we observed that PA affects bone metabolism and accelerates bone loss. Additionally, treatment with ATX was able to suppress the deleterious effects of PA and a simultaneous decrease in serum MDA levels and an increase in SOD was observed.

RESULTS

In addition, rats treated with ATX were observed to have significantly increased bone mass and elevated activity of SIRT1 and SOD2 in bone tissue. When MC3T3-E1 and RAW264.7 cells induced osteoblast and osteoclast differentiation, the ATX intervention was able to significantly restore the restriction of osteogenic differentiation and the up-regulation of osteoclast differentiation with PA therapy. Furthermore, we confirm that PA damage to cells is caused by increased oxidative stress, and that ATX can target and modulate the activity of SIRT1 to regulate the levels of oxidative stress in cells.

CONCLUSION

Summarizing, ATX may inhibit PA-induced bone loss through its antioxidant properties via the SIRT1 signaling pathway.

Skeleton-derived extracellular vesicles in bone and whole-body aging: From mechanisms to potential applications

The skeleton serves as a supportive and protective organ for the body. As individuals age, their bone tissue undergoes structural, cellular, and molecular changes, including the accumulation of senescent cells. Extracellular vesicles (EVs) play a crucial role in aging through the cellular secretome and have been found to induce or accelerate age-related dysfunction in bones and to contribute further via the circulatory system to the aging of phenotypes of other bodily systems. However, the extent of these effects and their underlying mechanisms remain unclear. Therefore, this paper attempts to give an overview of the current understanding of age-related alteration in EVs derived from bones. The role of EVs in mediating communications among bone-related cells and other body parts is discussed, and the significance of bones in the whole-body aging process is highlighted. Ultimately, it is hoped that gaining a clearer understanding of the relationship between EVs and aging mechanisms may serve as a basis for new treatment strategies for age-related degenerative diseases in the skeleton and other systems.

Amyloid-β neuropathology induces bone loss in male mice by suppressing bone formation and enhancing bone resorption

Alzheimer's disease (AD) and osteoporosis often coexist in the elderly. Although observational studies suggest an association between these two diseases, the pathophysiologic link between AD and skeletal health has been poorly defined. We examined the skeletal phenotype of 5xFAD mice, an AD model with accelerated neuron-specific amyloid-β accumulation causing full-blown AD phenotype by the age of 8 months. Micro-computed tomography indicated significantly lower trabecular and cortical bone parameters in 8-month-old male, but not female, 5xFAD mice than sex-matched wild-type littermates. Dynamic histomorphometry revealed reduced bone formation and increased bone resorption, and quantitative RT-PCR showed elevated skeletal RANKL gene expression in 5xFAD males. These mice also had diminished body fat percentage with unaltered lean mass, as determined by dual-energy X-ray absorptiometry (DXA), and elevated Ucp1 mRNA levels in brown adipose tissue, consistent with increased sympathetic tone, which may contribute to the osteopenia observed in 5xFAD males. Nevertheless, no significant changes could be detected between male 5xFAD and wild-type littermates regarding the serum and skeletal concentrations of norepinephrine. Thus, brain-specific amyloid-β pathology is associated with osteopenia and appears to affect both bone formation and bone resorption. Our findings shed new light on the pathophysiologic link between Alzheimer's disease and osteoporosis.

The immune cells in modulating osteoclast formation and bone metabolism

Osteoclasts are pivotal in regulating bone metabolism, with immune cells significantly influencing both physiological and pathological processes by modulating osteoclast functions. This is particularly evident in conditions of inflammatory bone resorption, such as rheumatoid arthritis and periodontitis. This review summarizes and comprehensively analyzes the research progress on the regulation of osteoclast formation by immune cells, aiming to unveil the underlying mechanisms and pathways through which diseases, such as rheumatoid arthritis and periodontitis, impact bone metabolism.

Integrating Network Pharmacology, Quantitative Metabolic Network Analysis, In Vitro Experiments, and Molecular Dynamics to Explore the Mechanism of Angelica Sinensis for Regulating Bone Metabolism

BACKGROUND

Bone metabolic diseases are serious health issues worldwide. Angelica sinensis (AS) is traditionally used in Chinese medicine for treating bone metabolism diseases clinically. However, the mechanism of AS in regulating bone metabolism remains uncertain.

OBJECTIVE

The current investigation was structured to elucidate the potential mechanisms of AS for modulating bone metabolism.

METHODS

Firstly, targets of AS regulating bone metabolism were collected by network pharmacology. Then, the transcriptional regulation of RUNX2 was enriched as one of the key pathways for AS to regulate bone metabolism, constructing its metabolic network. Secondly, combining molecular docking, network efficiency, and network flux analyses, we conducted a quantitative evaluation of the metabolic network to reveal the potential mechanisms and components of AS regulating bone metabolism. Finally, we explored the effect of AS on the differentiation of osteoclasts from M-CSF and RANKL-induced RAW264.7 cells, as well as its impact on the osteogenic induction of MC3T3-E1 cells. We verified the mechanism and key targets of AS on bone metabolism using qRT-PCR. Furthermore, the key component was preliminarily validated through molecular dynamics simulation.

RESULTS

Quantitative metabolic network of the transcriptional regulation of RUNX2 was constructed to illustrate the potential mechanism of AS for regulating bone metabolism, indicating that ferulic acid may be a pharmacological component of AS that interferes with bone metabolism. AS suppressed osteoclast differentiation in M-CSF and RANKL-induced RAW264.7 cells and reversed the expressions of osteoclastic differentiation markers, including RUNX2 and SRC. Additionally, AS induced osteogenic generation in MC3T3-E1 cells and reversed the expressions of markers associated with osteoblastic generation, such as RUNX2 and HDAC4. Molecular dynamics simulation displayed a strong binding affinity among ferulic acid, HDAC4 and SRC.

CONCLUSION

This study reveals a systematic perspective on the intervention bone mechanism of AS by transcriptive regulation by RUNX2, guiding the clinical use of AS in treating diseases of the skeletal system.

Research Progress on the Mechanism of the SFRP-Mediated Wnt Signalling Pathway Involved in Bone Metabolism in Osteoporosis

Osteoporosis (OP) is a metabolic bone disease linked to an elevated fracture risk, primarily stemming from disruptions in bone metabolism. Present clinical treatments for OP merely alleviate symptoms. Hence, there exists a pressing need to identify novel targets for the clinical treatment of OP. Research indicates that the Wnt signalling pathway is modulated by serum-secreted frizzled-related protein 5 (SFRP5), potentially serving as a pivotal regulator in bone metabolism disorders. Moreover, studies confirm elevated SFRP5 expression in OP, with SFRP5 overexpression leading to the downregulation of Wnt and β-catenin proteins in the Wnt signalling pathway, as well as the expression of osteogenesis-related marker molecules such as RUNX2, ALP, and OPN. Conversely, the opposite has been reported when SFRP5 is knocked out, suggesting that SFRP5 may be a key factor involved in the regulation of bone metabolism via the Wnt signalling axis. However, the molecular mechanisms underlying the action of SFRP5-induced OP have yet to be comprehensively elucidated. This review focusses on the molecular structure and function of SFRP5 and the potential molecular mechanisms of the SFRP5-mediated Wnt signalling pathway involved in bone metabolism in OP, providing reasonable evidence for the targeted therapy of SFRP5 for the prevention and treatment of OP.

Urinary Silicon Excretion in Relation to Lactation and Bone Mineral Density - a Longitudinal Study Post-partum

Silicon (Si) may be a mineral beneficial for bone health. Pregnancy and lactation have major impacts on maternal bone metabolism as bone minerals, including calcium (Ca), are required for growth of the foetus and for milk production. Like urinary Ca excretion, Si excretion has been reported to be high in pregnant women, but there are no data post-partum and during lactation. The aim of the present study was to investigate the urinary excretion of Si (U-Si), from the third trimester of pregnancy until 18 months post-partum, and in relation to the length of lactation, to determine if changes in U-Si are associated with changes in areal bone mineral density (aBMD). This longitudinal study included 81 pregnant women, of whom 56 completed the study. Spot urine samples were collected at the third trimester and at 0.5, 4, 12, and 18 months post-partum and were analysed for Si and Ca by ICP-OES. The aBMD was measured post-partum at lumbar spine and femoral neck by dual-energy x-ray absorptiometry. Women lactating for 4-8.9 and ≥ 9 months had significantly higher U-Si at 4 months post-partum, compared with the third trimester. No significant longitudinal differences in U-Si were found after correcting for creatinine. Changes in U-Si and in aBMD were not correlated, except at the lumbar spine from 0.5 to 12 months post-partum in the women lactating for 4-8.9 months. Taken together, our results suggest that there is a possibility that U-Si increases post-partum in women lactating for 4 months or longer, although it is not related to changes in aBMD.

Effects of sodium-glucose cotransporter 2 inhibitors on bone metabolism in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

Sodium glucose cotransporter 2 (SGLT2) inhibitors are widely used in type 2 diabetes mellitus (T2DM) therapy. The impact of SGLT2 inhibitors on bone metabolism has been widely taken into consideration. But there are controversial results in the study on the effect of SGLT2 inhibitors on bone metabolism in patients with T2DM. Therefore, we aimed to examine whether and to what extent SGLT2 inhibitors affect bone metabolism in patients with T2DM.

METHODS

A literature search of randomized controlled trials (RCTs) was conducted through PubMed, Web of Science, Embase, Cochrane databases, and Scopus from inception until 15 April 2023. Eligible RCTs compared the effects of SGLT2 inhibitors versus placebo on bone mineral density and bone metabolism in patients with T2DM. To evaluate the differences between groups, a meta-analysis was conducted using the random effects inverse-variance model by utilizing standardized mean differences (SMD).

RESULTS

Through screening, 25 articles were finally included, covering 22,828 patients. The results showed that, compared with placebo, SGLT2 inhibitors significantly increased parathyroid hormone (PTH, SMD = 0.13; 95%CI: 0.06, 0.20), and cross-linked C-terminal telopeptides of type I collagen (CTX, SMD = 0.11; 95%CI: 0.01, 0.21) in patients with T2DM, decreased serum alkaline phosphatase levels (ALP, SMD = -0.06; 95%CI: -0.10, -0.03), and had no significant effect on bone mineral density (BMD), procollagen type 1 N-terminal propeptide (P1NP), 25-hydroxy vitamin D, tartrate resistant acid phosphatase-5b (TRACP-5b) and osteocalcin.

CONCLUSIONS

SGLT2 inhibitors may negatively affect bone metabolism by increasing serum PTH, CTX, and decreasing serum ALP. This conclusion needs to be verified by more studies due to the limited number and quality of included studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, identifier CRD42023410701.

The impact and mechanism of nerve injury on bone metabolism

With an increasing understanding of the mechanisms of fracture healing, it has been found that nerve injury plays a crucial role in the process, but the specific mechanism is yet to be completely revealed. To address this issue and provide novel insights for fracture treatment, we compiled this review. This review aims to study the impact of nerve injury on fracture healing, exploring the role of neurotrophic factors in the healing process. We first revisited the effects of the central nervous system (CNS) and the peripheral nervous system (PNS) on the skeletal system, and further explained the phenomenon of significantly accelerated fracture healing under nerve injury conditions. Then, from the perspective of neurotrophic factors, we delved into the physiological functions and mechanisms of neurotrophic factors, such as nerve growth factor (NGF), Neuropeptides (NPs), and Brain-derived neurotrophic factor (BDNF), in bone metabolism. These effects include direct actions on bone cells, improvement of local blood supply, regulation of bone growth factors, control of cellular signaling pathways, promotion of callus formation and bone regeneration, and synergistic or antagonistic effects with other endocrine factors, such as Sema3A and Transforming Growth Factor β (TGF-β). Finally, we discussed the treatments of fractures with nerve injuries and the future research directions in this review, suggesting that the relationship between nerve injury and fracture healing, as well as the role of nerve injury in other skeletal diseases.

The role and mechanism of RNA-binding proteins in bone metabolism and osteoporosis

Osteoporosis is a prevalent chronic metabolic bone disease that poses a significant risk of fractures or mortality in elderly individuals. Its pathophysiological basis is often attributed to postmenopausal estrogen deficiency and natural aging, making the progression of primary osteoporosis among elderly people, especially older women, seemingly inevitable. The treatment and prevention of osteoporosis progression have been extensively discussed. Recently, as researchers delve deeper into the molecular biological mechanisms of bone remodeling, they have come to realize the crucial role of posttranscriptional gene control in bone metabolism homeostasis. RNA-binding proteins, as essential actors in posttranscriptional activities, may exert influence on osteoporosis progression by regulating the RNA life cycle. This review compiles recent findings on the involvement of RNA-binding proteins in abnormal bone metabolism in osteoporosis and describes the impact of some key RNA-binding proteins on bone metabolism regulation. Additionally, we explore the potential and rationale for modulating RNA-binding proteins as a means of treating osteoporosis, with an overview of drugs that target these proteins.

The effect of aquatic training and vitamin D3 supplementation on bone metabolism in postmenopausal obese women

Purpose

Despite prevalence of studies indicating the positive effect of land-based exercise on bone metabolism, there are limited findings regarding the effect of aquatic exercise. The present study aimed to evaluate the effects of aquatic training and vitamin D3 supplementation on femur bone mineral density (BMD), serum 25(OH)D, and parathyroid hormone (PTH) in postmenopausal obese women with vitamin D insufficiency.

Methods

40 postmenopausal obese women were randomly divided into four groups of aquatic training + vitamin D3 intake group; (ATD), aquatic training with placebo intake group (AT), vitamin D3 intake group (D), and control group with placebo intake (CON). AT groups performed aerobic aquatic exercises for 8 weeks. Vitamin D3 supplementation groups consumed oral dose of 4000 IU/d for 8 weeks.

Results

The femur BMD was significantly higher in the ATD than the AT and D and CON groups; in AT it was higher than the D and CON groups. Serum 25(OH)D level in the ATD was more than AT and CON, and in the D was more than the CON and AT. PTH in the ATD group was lower compared to AT, D, and CON groups. PTH was lower in the AT and D compared to the CON.

Conclusion

In postmenopausal obese women with vitamin D insufficiency or deficiency, combining vitamin D supplementation and aquatic training was the most effective method for improving bone metabolism; Vitamin D supplementation (alone) was not sufficient to affect some of bone metabolism indices; Aquatic training could not improve serum vitamin D. By priority, ATD, AT, and D indicated better bone related metabolism indices.

A novel mechanism of Vildagliptin in regulating bone metabolism and mitigating osteoporosis

Osteoporosis has become a global social problem with the tendency toward the aging population. The challenge in managing osteoporosis is to develop new anti-osteoporosis drugs that target bone anabolism. The purpose of this study was to uncover the novel mechanism of Vildagliptin on bone metabolism. We revealed that Vildagliptin significantly promoted osteogenic differentiation of precursor osteoblasts and bone marrow mesenchymal stem cells (BMSCs). At the same time, it significantly enhanced the polarization of RAW264.7 macrophages to the M2 type and the secretion of osteogenic factors BMP2 and TGF-β1. This was confirmed by the increased osteogenic differentiation observed in the osteoblast-RAW264.7 co-culture system. Moreover, Vildagliptin significantly enhanced the transformation of BMSCs into the osteogenic morphology in the osteoblast-BMSC co-culture system. Finally, Vildagliptin also inhibited osteoclastic differentiation of RAW 264.7 cells. The potential mechanism underlying these effects involved targeting the GAS6/AXL/ERK5 pathway. In the in vivo study, Vildagliptin significantly alleviated postmenopausal osteoporosis in ovariectomized mice. These findings represent the first comprehensive revelation of the regulatory effect of Vildagliptin on bone metabolism. Specifically, Vildagliptin demonstrates the ability to promote bone anabolism and inhibit bone resorption by simultaneously targeting osteoblasts, BMSCs, and osteoclasts. The bone-protective effects of Vildagliptin were further confirmed in a postmenopausal osteoporosis model. The clinical significance of this study lies in laying a theoretical foundation for bone protection therapy in type-2 diabetes patients with compromised bone conditions or postmenopausal osteoporosis.

Short-term effects of Roux-en-Y gastric bypass or gastric sleeve on bone mineral density and calciotropic hormones: a systematic review and meta-analysis

Roux-en-Y gastric bypass (RYGB) and gastric sleeve (GS) have been associated with significant reductions in bone mineral density (BMD) and fluctuations in serum levels of calciotropic hormones. These changes pose a risk to bone health. The study assessed the short-term (12 and 24 months) effects of RYGB and GS on BMD and calciotropic hormones. PubMed, Embase, and Cochrane Library databases were searched. Analyses considered follow-up (12 and 24 months) with BMD as main outcome at three sites (femoral neck, total hip, and lumbar spine) and one for each calciotropic hormone (25 OH vitamin D and parathyroid hormone [PTH]). Estimated effect sizes were calculated as standardized mean differences (SMD), confidence interval of 95%, and P value. Nine studies totaling 473 participants (RYGB = 261 and GS = 212) were included. RYGB resulted in lower BMD than GS at 12 months for femoral neck (SMD = -0.485, 95% CI [-0.768, -0.202], P = .001), lumbar spine (SMD = -0.471, 95% CI [-0.851, -0.092], P = .015), and total hip (SMD = -0.616, 95% CI [-0.972, -0.259], P = .001), and at 24 months for total hip (SMD = -0.572, 95% CI [-0.907, -0.238], P = .001). At 24 months, 25 OH vitamin D was lower in RYGB than GS (SMD = -0.958 [-1.670, -0.245], P = .008) and PTH levels were higher in RYGB than in GS (SMD = 0.968 [0.132, 1.804, P = .023]). RYGB demonstrated significant reduction in regional BMD. It also induces lower serum 25 OH vitamin D and higher PTH levels than GS. The results support the need for preventive bone health measures in the short-term postoperative period, especially in the case of RYGB.

Effects of acute- and long-term aerobic exercises at different intensities on bone in mice

INTRODUCTION

Exercise intensity determines the benefits of aerobic exercise. Our objectives were, in aerobic exercise at different intensities, to determine (1) changes in bone metabolism-related genes after acute exercise and (2) changes in bone mass, strength, remodeling, and bone formation-related proteins after long-term exercise.

MATERIALS AND METHODS

Total 36 male C57BL/6J mice were divided into a control group and exercise groups at 3 different intensities: low, moderate, or high group. Each exercise group was assigned to acute- or long-term exercise groups. Tibias after acute exercise were evaluated by real-time PCR analysis. Furthermore, hindlimbs of long-term exercise were assessed by micro-CT, biomechanical, histological, and immunohistochemical analyses.

RESULTS

Acute moderate-intensity exercise decreased RANKL level as bone resorption marker, whereas low- and high-intensity exercise did not alter it. Additionally, only long-term exercise at moderate intensity increased bone mass and strength. Moderate-intensity exercise promoted osteoblast activity and suppressed osteoclast activity. After low- and high-intensity exercise, osteoblast and osteoclast activity were unchanged. An increase in the number of β-catenin-positive cells and a decrease in sclerostin-positive cells were observed in the only moderate group.

CONCLUSION

These results showed that moderate-intensity exercise can inhibit bone resorption earlier, and long-term exercise can increase bone mass and strength through promoted bone formation via the Wnt/β-catenin activation. High-intensity exercise, traditionally considered better for bone, may fail to stimulate bone remodeling, leading to no change in bone mass and strength. Our findings suggest that moderate-intensity exercise, neither too low nor high, can maintain bone health.

Correlations between bone metabolism biomarkers and fluoride exposure in adults and children

Increased exposure to fluoride, which notably affects bone metabolism, is a global concern. However, the correlations and sensitivity of bone metabolism to fluoride remain controversial. In this cross-sectional study, 549 children (aged 7-12 years) and 504 adults (≥ 18 years old) were recruited in the high-fluoride areas of the Henan Province. Urinary fluoride (UF) level was determined using a fluoride electrode. Fasting venous blood serum was collected to measure bone metabolism biomarkers. The selected bone metabolism biomarkers for children included bone alkaline phosphatase (BALP), serum alkaline phosphatase (ALP), osteocalcin (OCN), calcitonin (CT), parathyroid hormone (PTH), phosphorus (P5+), and calcium (Ca2+). For adults, the biomarkers included ALP, CT, PTH, β-CrossLaps (β-CTX), P5+, and Ca2+. The correlations between UF and bone metabolism biomarkers were analyzed using binary logistic regression, a trend test, a generalized additive model, and threshold effect analysis. Regression analysis indicated a significant correlation between serum OCN, PTH, and UF levels in children aged 7-9 years. Serum OCN, PTH, and BALP contents were significantly correlated with UF in boys (P < 0.05). Furthermore, the interaction between age and UF affected serum P5+ and PTH (P < 0.05). The generalized additive model revealed nonlinear dose-response relationships between P5+, BALP, and UF contents in children (P < 0.05). Serum OCN level was linearly correlated with the UF concentration (P < 0.05). Similarly, a significant correlation was observed between β-CTX and UF levels in adults. In addition, significant correlations were observed between UF-age and serum Ca2+, β-CTX, and PTH contents. There was a non-linear correlation between serum Ca2+, P5+, and β- CTX and UF levels (P < 0.05). Overall, serum OCN, BALP, and P5+ levels can serve as sensitive bone metabolism biomarkers in children, while β-CTX, P5+, and Ca2+ can be considered fluoride-sensitive bone metabolism biomarkers in adults.

Effect of moxibustion for "nourishing the kidney and benefiting the marrow" on knee osteoarthritis

OBJECTIVES

To compare the clinical effect between two acupoint regimens of moxibustion on knee osteoarthritis (KOA), and observe the influences on the serum content of interleukin 1α (IL-1α), interleukin-17A (IL-17A), tumor necrosis factor α (TNF-α), bone gla protein (BGP) and osteoprotegerin (OPG).

METHODS

KOA patients were randomly divided into an observation group (40 cases, 2 cases dropped off) and a control group (40 cases, 3 cases dropped off). In the observation group, moxibustion was applied to Xiyan (EX-LE5), Dubi (ST35), Zusanli (ST36), Dazhu (BL11), Xuanzhong (GB39) and Yongquan (KI1) on the affected side. In the control group, EX-LE5, ST35 and ST36 were selected on the affected side. One session of treatment took 30 min in each group, delivered 3 times a week and the duration of treatment was 4 weeks. The scores of Western Ontario and McMaster University (WOMAC) and visual analogue scale (VAS) were observed and the serum content of IL-1α, IL-17A, TNF-α, BGP and OPG of the two groups were measured before and after treatment.

RESULTS

Compared with those before treatment, the WOMAC score, VAS score and the serum content of IL-1α, IL-17A and TNF-α were decreased (P<0.05), and the content of BGP and OPG were increased (P<0.05) after treatment. Compared with the control group, the WOMAC score, VAS score and the serum content of IL-1α and TNF-α in the observation group were lower (P<0.05), and the content of BGP and OPG were higher (P<0.05). The total effective rate of the observation group was 89.5% (34/38), and that of the control group was 83.8% (31/37), with no statistically significant difference.

CONCLUSIONS

Moxibustion therapy of "nourishing the kidney and benefiting the marrow" can relieve joint pain, improve joint function, reduce the level of inflammatory factors and ameliorate bone metabolic indicators. The effect of the acupoint regimen in this moxibustion therapy is better than that of the local acupoint selection.

The differential effect of modern intravenous iron on fibroblast growth factor 23 and phosphate in non-dialysis dependent CKD - the exploratory randomized controlled double-blind ExplorIRON-CKD study

BACKGROUND

Intravenous iron is commonly used in patients with non-dialysis-dependent chronic kidney disease (CKD). Modern intravenous iron compounds (e.g. ferric derisomaltose (FDI), ferric carboxymaltose (FCM)) are increasingly utilized with similar efficacy. A differential effect in terms of hypophosphatemia has been noted following administration of FCM, which may be related to fibroblast growth factor 23 (FGF23). This study was designed to examine the comparative effects of FDI and FCM on FGF23, phosphate and other markers of bone turnover.

METHODS

The single-center double-blind randomized controlled trial "Iron and Phosphaturia - ExplorIRON-CKD" primarily assessed the effects of FCM and FDI on intact FGF23 and phosphate, whilst also studying the impact on vitamin D, parathyroid hormone and phosphaturia. Bone markers including alkaline phosphatase, bone-specific alkaline phosphatase, procollagen type 1 N-terminal propeptide and carboxy-terminal collagen cross-linked telopeptide were monitored. Non-dialysis-dependent CKD patients (stage 3a-5) with iron deficiency with/without anemia (serum ferritin < 200 µg/L or transferrin saturation = 20% and serum ferritin 200-299 µg/L) were randomized to receive FDI or FCM in a 1:1 ratio. At baseline 1000 mg of intravenous iron was administered followed by 500-1000 mg at 1 month to achieve replenishment. Measurements were performed at baseline, 1-2 days following iron administration, 2 weeks, 1 month (second iron administration), 1-2 days following second administration, 2 months and 3 months following initial infusion.

RESULTS

Twenty-six patients participated in the trial; 14 randomized to FDI and 12 to FCM. Intact FGF23 increased following administration of iron, and the increase was significantly higher with FCM compared to FDI (Baseline to 1-2 days following 1st administration: FDI: 3.0 (IQR: - 15.1 - 13.8) % vs. FCM: 146.1 (IQR: 108.1-203.1) %; p < 0.001 and Baseline to 1-2 days following 2nd administration: FDI: 3.2 (IQR: - 3.5 - 25.4) % vs. FCM: 235.1 (138.5-434.6) %; p = 0.001). Phosphate levels decreased in the FCM group, causing a significant difference versus FDI 2 weeks following administration of the first dose. A significantly greater decrease in 1,25 (OH)2 Vitamin D was noted with FCM. Several markers of bone turnover significantly changed following administration of FCM but not FDI.

CONCLUSIONS

The study suggests a differential effect on FGF23 following administration of FCM compared to FDI in non-dialysis-dependent CKD patients, similar to other patient groups. This may lead to changes consistent with hypovitaminosis D and alterations in bone turnover with potential clinical consequences. Further definitive studies are required to understand these differences of intravenous iron compounds.

TRIAL REGISTRATION

European Union Drug Regulating Authorities Clinical Trials Database (EudraCT) number: 2019-004370-26 ( https://www.clinicaltrialsregister.eu/ctr-search/trial/2019-004370-26/GB ) (First date of trial registration: 03/12/2019).

Enhanced molecular release from elderly bone samples using collagenase I: insights into fatty acid metabolism alterations

BACKGROUND

Bone is a metabolically active tissue containing different cell types acting as endocrine targets and effectors. Further, bone is a dynamic depot for calcium, phosphorous and other essential minerals. The tissue matrix is subjected to a constant turnover in response to mechanical/endocrine stimuli. Bone turnover demands high energy levels, making fatty acids a crucial source for the bone cells. However, the current understanding of bone cell metabolism is poor. This is partly due to bone matrix complexity and difficulty in small molecules extraction from bone samples. This study aimed to evaluate the effect of metabolite sequestering from a protein-dominated matrix to increase the quality and amount of metabolomics data in discovering small molecule patterns in pathological conditions.

METHODS

Human bone samples were collected from 65 to 85 years old (the elderly age span) patients who underwent hip replacement surgery. Separated cortical and trabecular bone powders were treated with decalcifying, enzymatic (collagenase I and proteinase K) and solvent-based metabolite extraction protocols. The extracted mixtures were analyzed with the high-resolution mass spectrometry (HRMS). Data analysis was performed with XCMS and MetaboAnalystR packages.

RESULTS

Fast enzymatic treatment of bone samples before solvent addition led to a significantly higher yield of metabolite extraction. Collagenase I and proteinase K rapid digestion showed more effectiveness in cortical and trabecular bone samples, with a significantly higher rate (2.2 folds) for collagenase I. Further analysis showed significant enrichment in pathways like de novo fatty acid biosynthesis, glycosphingolipid metabolism and fatty acid oxidation-peroxisome.

CONCLUSION

This work presents a novel approach for bone sample preparation for HRMS metabolomics. The disruption of bone matrix conformation at the molecular level helps the molecular release into the extracting solvent and, therefore, can lead to higher quality results and trustable biomarker discovery. Our results showed β-oxidation alteration in the aged bone sample. Future work covering more patients is worthy to identify the effective therapeutics to achieve healthy aging.

Potential Role of Bone Metabolism Markers in Kidney Transplant Recipients

BACKGROUND

The impact of treatments, suppressing the immune system, persistent hyperparathyroidism, and other risk factors on mineral and bone disorder (MBD) after kidney transplantation is well-known. However, there is limited knowledge about their effect on bone metabolism biomarkers. This study aimed to investigate the influence of kidney transplant on these markers, comparing them to patients undergoing hemodialysis and healthy individuals.

METHODS

In this cross-sectional study, three groups were included: kidney transplant patients (n = 57), hemodialysis patients (n = 26), and healthy controls (n = 31). Plasma concentrations of various bone metabolism biomarkers, including Dickkopf-related protein 1, osteoprotegerin, osteocalcin, osteopontin, sclerostin, and fibroblast growth factor 23, were measured. Associations between these biomarkers and clinical and laboratory data were evaluated.

RESULTS

A total of 114 patients participated. Transplant recipients had significantly lower levels of Dickkopf-related protein 1, osteoprotegerin, osteocalcin, osteopontin, sclerostin, and fibroblast growth factor 23 compared to hemodialysis patients. Alkaline phosphatase levels positively correlated with osteopontin (r = 0.572, p < 0.001), while fibroblast growth factor 23 negatively correlated with 25-hydroxyvitamin D (r = -0.531, p = 0.019). The panel of bone biomarkers successfully predicted hypercalcemia (area under the curve [AUC] = 0.852, 95% confidence interval [CI] = 0.679-1.000) and dyslipidemia (AUC = 0.811, 95% CI 0.640-0.982) in transplant recipients.

CONCLUSION

Kidney transplantation significantly improves mineral and bone disorders associated with end-stage kidney disease by modulating MBD markers and reducing bone metabolism markers, such as Dickkopf-related protein 1, osteoprotegerin, osteocalcin, osteopontin, and sclerostin. Moreover, the panel of bone biomarkers effectively predicted hypercalcemia and dyslipidemia in transplant recipients.

The influence of radiation-induced bystander effect in osteoblasts mediated by plasma-derived extracellular vesicles (EVs)

OBJECTIVES

Head and neck tumor patients may develop post-radiotherapy diseases after radiotherapy treatment. And radiotherapy can elicit radiation-induced bystander effect, wherein extracellular vesicles (EVs) play a crucial role. For normal parts of the body that have not been directly irradiated, the effect of EVs on them needs to be further explored. This study aims to investigate the functions of plasma-derived EVs in regulating normal osteoblasts during radiation-induced bystander effects.

METHODS AND MATERIALS

Rat plasma-derived EVs were isolated and identified firstly, followed by an evaluation of their intracellular biological effects on normal osteoblasts in vitro. Transcriptome sequencing analysis and confirmations were performed to identify potential mechanisms.

RESULTS

Irradiated plasma-derived EVs were found to enhance osteoblast proliferation, migration, and cell cycle progression, concurrently suppressing the expression of osteogenesis-related genes and proteins. Furthermore, these EVs attenuated the expression of osteogenesis and oxidative stress resistance related genes, while upregulating the PI3K-AKT pathway and intracellular reactive oxygen species in osteoblasts.

CONCLUSIONS

Irradiated plasma-derived EVs could alter the biological effects in osteoblasts, which is closely associated with the levels of GPX1 and the PI3K-AKT signaling pathway. This suggests that plasma-derived EVs serve as a crucial factor contributing to radiation-induced bystander effect in osteoblasts.

Bone health and body composition in transgender adults before gender-affirming hormonal therapy: data from the COMET study

PURPOSE

Preliminary data suggested that bone mineral density (BMD) in transgender adults before initiating gender-affirming hormone therapy (GAHT) is lower when compared to cisgender controls. In this study, we analyzed bone metabolism in a sample of transgender adults before GAHT, and its possible correlation with biochemical profile, body composition and lifestyle habits (i.e., tobacco smoke and physical activity).

METHODS

Medical data, smoking habits, phospho-calcic and hormonal blood tests and densitometric parameters were collected in a sample of 125 transgender adults, 78 Assigned Females At Birth (AFAB) and 47 Assigned Males At Birth (AMAB) before GAHT initiation and 146 cisgender controls (57 females and 89 males) matched by sex assigned at birth and age. 55 transgender and 46 cisgender controls also underwent a complete body composition evaluation and assessment of physical activity using the International Physical Activity Questionnaire (IPAQ).

RESULTS

14.3% of transgender and 6.2% of cisgender sample, respectively, had z-score values < -2 (p = 0.04). We observed only lower vitamin D values in transgender sample regarding biochemical/hormonal profile. AFAB transgender people had more total fat mass, while AMAB transgender individuals had reduced total lean mass as compared to cisgender people (53.94 ± 7.74 vs 58.38 ± 6.91, p < 0.05). AFAB transgender adults were more likely to be active smokers and tend to spend more time indoor. Fat Mass Index (FMI) was correlated with lumbar and femur BMD both in transgender individuals, while no correlations were found between lean mass parameters and BMD in AMAB transgender people.

CONCLUSIONS

Body composition and lifestyle factors could contribute to low BMD in transgender adults before GAHT.

The influence of iron on bone metabolism disorders

Iron is a necessary trace element in the human body, and it participates in many physiological processes. Disorders of iron metabolism can cause lesions in many tissues and organs, including bone. Recently, iron has gained attention as an independent factor influencing bone metabolism disorders, especially the involvement of iron overload in osteoporosis. The aim of this review was to summarize the findings from clinical and animal model research regarding the involvement of iron in bone metabolism disorders and to elucidate the mechanisms behind iron overload and osteoporosis. Lastly, we aimed to describe the association between bone loss and iron overload. We believe that a reduction in iron accumulation can be used as an alternative treatment to assist in the treatment of osteoporosis, to improve bone mass, and to improve the quality of life of patients.

Association between thymic hyperplasia and serum calcium level in Graves' disease

BACKGROUND

Graves' disease increases bone resorption in hyperthyroidism, leading to elevated serum calcium levels and a negative bone balance. Thymic hyperplasia is observed in some Graves' disease patients. What's more, there have been a few reports of increased serum calcium and severe osteoporosis induced by Graves' disease with thymic hyperplasia. It remains unclear whether Graves' disease with thymic hyperplasia is associated with higher serum calcium levels. Our study aimed to investigate the possibility of elevated serum calcium levels and aggravated bone mobilization in Graves' disease patients with thymic hyperplasia.

METHODS

Newly diagnosed and untreated patients with Graves' disease (n = 96) were enrolled. They were divided into two groups based on the incidental detection of thymic hyperplasia during imaging. Albumin, alkaline phosphatase, calcium, free triiodothyronine, free thyroxine, thyroid-stimulating hormone, and thyrotrophin receptor antibody (TRAb) were measured, and a computerized tomography of the chest was obtained.

RESULTS

Patients with Graves' disease who had thymic hyperplasia were notably younger (P=0.018) and exhibited higher serum calcium levels (P=0.001) compared to those with Graves' disease without thymic hyperplasia. In the multiple regression analysis, thymic hyperplasia, TRAb, and female gender were significant variables associated with elevated serum calcium levels in patients with Graves' disease, collectively accounting for 31.7% of the variation in serum calcium.

CONCLUSIONS

Graves' disease patients with thymic hyperplasia showed higher serum calcium levels. thymic hyperplasia, TRAb, and female gender were found to be correlated with increased serum calcium levels in Graves' disease, suggesting a potential association between thymic hyperplasia and bone mobilization in Graves' disease.

Niacin treatment prevents bone loss in iron overload osteoporotic rats via activation of SIRT1 signaling pathway

Recently, more and more studies have revealed that iron overload can lead to osteoporosis by inducing oxidative stress. Niacin (NAN), also known as nicotinate or vitamin B3, has been confirmed to possess potent antioxidative effects. In addition, very little is currently known about the protective effects of NAN on iron overload in osteoporotic bone tissue. Therefore, we aimed to evaluate the protective effect of niacin on iron overload-induced bone injury and to investigate the effect and underlying mechanisms of the niacin and iron overload on intracellular antioxidant properties. When MC3T3-E1 and RAW264.7 cells were cultured in the presence of ammonium ferric citrate(FAC), NAN therapy could increase the matrix mineralization and promote expression of osteogenic markers in MC3T3-E1, inhibit osteoclastic differentiation of RAW264.7 cells, while increasing intracellular reactive oxygen species (ROS) levels and strengthening mitochondrial membrane potential (MMP). In the ovariectomized (OVX) rat model, NAN had an obvious protective effect against iron-overloaded injury. Meanwhile, superoxide dismutase 2 (SOD2), intracellular antioxidant enzymes and silent information regulator type 1 (SIRT1), were up-regulated in response to NAN exposures in MC3T3-E1. Furthermore, SIRT1 inhibitor EX527 attenuated the protective effects of NAN. Results revealed that NAN could stimulate osteogenic differentiation, inhibit osteoclastic differentiation and markedly increased antioxidant properties in cells through the induction of SIRT1. Studies suggest that niacin is a promising agent for preventing bone loss in iron overload conditions.

Advances in the research on myokine-driven regulation of bone metabolism

The traditional view posits that bones and muscles interact primarily through mechanical coupling. However, recent studies have revealed that myokines, proteins secreted by skeletal muscle cells, play a crucial role in the regulation of bone metabolism. Myokines are widely involved in bone metabolism, influencing bone resorption and formation by interacting with factors related to bone cell secretion or influencing bone metabolic pathways. Here, we review the research progress on the myokine regulation of bone metabolism, discuss the mechanism of myokine regulation of bone metabolism, explore the pathophysiological relationship between sarcopenia and osteoporosis, and provide future perspectives on myokine research, with the aim of identify potential specific diagnostic markers and therapeutic entry points.

Early bone loss in patients with obstructive sleep apnea: a cross-sectional study

BACKGROUND

Obstructive sleep apnea (OSA) and osteoporosis are both prevalent diseases with shared pathophysiological mechanisms and risk factors. However, the association between the two diseases is seldom studied. This study aimed to identify the link between OSA and bone metabolism.

METHODS

Male participants aged 30-59-years who visited the sleep clinic were continuously recruited. Polysomnography was used to evaluate sleep and respiratory conditions. Blood samples were collected to detect metabolic, inflammatory and bone turnover indicators. High-resolution peripheral quantitative computer tomography was used to measure the non-dominant lateral radius and tibia.

RESULTS

Ninety subjects were recruited. The cortical area (Ct.Ar) of tibia of the severe OSA group was significantly higher than that of the mild and moderate OSA groups (P = 0.06 and P = 0.048). There were significant differences between the four groups in terms of total volumetric bone mineral density (vBMD) (F = 2.990, P = 0.035), meta trabecular vBMD (F = 3.696, P = 0.015), trabecular thickness (Tb.Th) (F = 7.060, P = 0.000) and cortical thickness (Ct.Th) (F = 4.959, P = 0.003). The mean values of the OSA groups were lower than control group. Hypopnea index and percentage of total sleep time with SpO2 < 90% were both positively correlated with alkaline phosphatase (R = 0.213, P = 0.044; R = 0.212, P = 0.045). Sleep efficiency was correlated with multiple indicators of the radius.

CONCLUSIONS

In non-elderly male populations, OSA patients tended to have lower vBMD, Tb.Th and Ct.Th than non-OSA patients. The negative effect of OSA may mainly affect the osteogenesis process, and is presumed to be related to sleep-related hypoxemia and sleep efficiency.

Association of lymphocyte subsets and cytokines with bone metabolism: a retrospective, cross-sectional study

BACKGROUND

Previous research has shown that lymphocytes and cytokines can mediate bone metabolism. This study explored the clinical association and predictive ability of lymphocytes and cytokines levels for bone metabolism.

METHODS

A total of 162 patients were enrolled in this study. The levels of N-terminal propeptide of type I procollagen (P1NP), β-collagen degradation product (β-CTX), total T lymphocytes, immature T lymphocytes, suppressor/cytotoxic T lymphocytes, helper/inducer T lymphocytes, B lymphocytes, natural killer (NK) cells, Interferon-gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α), IFN-α, interleukin-1 beta (IL-1β), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, and IL12p70 were evaluated. The relationship between these lymphocyte subsets and cytokines with bone metabolic status was examined and their predictive ability for bone metabolic status was assessed.

RESULTS

The principal component analysis (PCA) and correlation analysis results varied on differences in lymphocyte subsets and cytokines in various bone metabolism states. Differential analysis revealed significant differences in the absolute counts of B lymphocytes (P < 0.05), level of IL-12p70 (P < 0.05), and IL-8 (P < 0.001) at different P1NP levels. Significant differences were observed in the absolute counts of total T lymphocytes (P < 0.05), B lymphocytes (P < 0.05), the level of IL-6 (P < 0.05), the percentage of B lymphocytes (P < 0.01), and NK cells (P < 0.05) at different β-CTX levels. Furthermore, the receiver operating characteristic (ROC) curve showed that the absolute count of B lymphocytes and levels of IL-12p70 and IL-8 could be used to evaluate bone formation states, while the absolute counts of T and B lymphocytes, level of IL-6, and percentages of NK cells and B lymphocytes could be used to evaluate bone resorption states.

CONCLUSION

The bone metabolism status changed based on the lymphocyte subsets and cytokine levels. Differentially expressed lymphocytes and cytokines could be used to distinguish bone metabolism status.

Exploring the boost of steaming with wine on Ligustri Lucidi Fructus in treating postmenopausal osteoporosis based on superior "multi-component structure" and iron/bone metabolism coregulation

BACKGROUND

Clinical studies indicated that postmenopausal osteoporosis (PMOP) often accompanied by iron overload risk factor, which exacerbated bone metabolism disorders and accelerated PMOP. Previous research found that multicomponent in Ligustri Lucidi Fructus (FLL) or wine-steamed FLL (WFLL) acted on the common targets of iron overload and PMOP simultaneously, which indicated that FLL and WFLL probably regulated iron/bone metabolism dually. Additionally, WFLL had more superior effect according to the theory of Chinese medicine for thousands of years.

PURPOSE

To reveal the "superior multi-component structure (SMCS)" and its molecular mechanisms in parallelly down-regulating iron overload and rescuing bone metabolism by WFLL.

DESIGNS AND METHODS

HPLC fingerprinting was established to compare the chemical profiles of FLL and WFLL; Then, the chemical compositions and quality markers of FLL and WFLL were analyzed by UPLC-Orbitrap-MS/MS coupled with OPLS-DA; the dynamic contents of quality markers and the multi-component structure at different wine steaming times (WST) were simultaneously determined by HPLC-DAD. Meanwhile, the dynamic efficacy of FLL at different WST were hunt by systematic zebrafish model. Subsequently, potential mechanism of WFLL in treating PMOP accompanied with iron overload was obtained from network pharmacology (NP) and molecular docking (MD). Finally, zebrafish and ovariectomy rat model were carried out to validate this potential mechanism.

RESULTS

HPLC fingerprints similarity of 15 batches in FLL and WFLL were among 0.9-1.0. 126 compositions were identified, including 58 iridoids, 25 terpenes, 30 phenylethanoids, 7 flavonoids and 6 others. 20 quality markers associated with WFLL was revealed, and the ratio of phenylethanols: Iridoids: Triterpenes (P/I/T) was converted from 1: 15: 4.5 to 1: 0.8: 0.9 during steaming (0 - 24 h) calculated by the quantification of 11 quality markers; the bone mineralization and motor performance of zebrafish larvae indicated that the optimum efficacy of WFLL at 12 h (p < 0.05) in which the SMCS of P/I/T was converted to 1: 4: 1.8. NP discovered that BMP-Smad pathway is one of the potential mechanisms of FLL in anti PMOP and then regulated bone formation and iron overload simultaneously. MD revealed that 17 active ingredients and 10 core targets genes could spontaneously bind with appropriate affinity. Rats model verified that FLL and WFLL significantly reversed PMOP, based on the improvement in bone formation indexes (ALP, OPG, OGN), iron metabolism indicators (hepcidin, ferritin), bone microstructure (BMD, BV/TV, Tb. Th, Tb. N); Moreover, WFLL significant enhanced reversal effect in anti-PMOP compared to FLL (p < 0.05). FLL and WFLL increased genes and proteins expression (Hep, BMP-6, p-Smad1/5, Smad4) related to BMP-Smad pathway compared with model group, and WFLL was more superior than FLL (p< 0.05).

CONCLUSION

The SMCS of FLL was optimized by wine-steam, WFLL represented a dual effect in downregulating iron overload and promoting bone formation, and the BMP-Smad pathway is one of the potential molecular mechanisms.

Evaluation of Bone Turnover Markers Such as Osteoprotegerin, Sclerostin and Dickkopf-1 in Subclinical Hyperthyroidism

In this study, it was aimed to assess effects of subclinical hyperthyroidism (SH) on bone metabolism using osteoprotegerin (OPG), sclerostin, Dickkopf-1 (DKK1) and biochemical parameters. This cross-sectional prospective study included 40 patients with SH and 40 euthyroid controls. Serum OPG, sclerostin, DKK-1, type-1 procollagen, C-terminal polypeptide (CTx) and 24-hours urine N-terminal telopeptide (NTx) were measures using ELISA kit. Bone mineral density measurements were performed using dual energy X-ray absorptiometry (DEXA). Risk for 10-years hip and major fracture was estimated by Turkish version of FRAX. No significant difference was detected in age, gender, body mass index, smoking and menopause rates between SH and control groups. The risk for 10-years hip fracture and major osteoporotic fracture were estimated as 4.45% and 0.55% in SH group, respectively. The OPG levels were significantly lower in patients with SH than controls (P = 0.017). No significant difference was detected in other bone formation and degradation parameters. No significant correlation was detected between OPG level and risk for major osteoporotic fracture (P > 0.05); however, a negative correlation was detected between OPG level and risk for hip fracture (rho = 0.233; P = 0.038). Serum OPG is markedly affected in patients with SH. In addition, OPG seemed to be associated with osteoporotic fracture risk. Available data show that SH is significantly associated with risk for fracture; thus, it is important to assess risk for fracture in patients with SH.

Short-Term Impact of Hematopoietic Stem Cell Transplantation on Depressive Behavior, Cognition and Quality of Life in Leukemia Patients

Hematopoietic stem cell transplantation (HSCT) or Bone Marrow Transplantation (BMT) has significantly improved the survival rates of patients suffering from hematological malignancies. However, the cure can only be achieved at the price of morbidity and long-term complications. Thus, this study aimed to evaluate the short-term effect of HSCT on depressive behavior, cognition, and quality of life (QoL) in leukemia patients. Sixty patients were included in this prospective observational study. The current study assessed depression using Patient Health Questionnaire (PHQ-9) scale, cognition using Montreal Cognitive Assessment (MOCA) scale and QoL using European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ C30) before 7 days of the therapy i.e., preconditioning/baseline (TP1) and after 30 days of the treatment (TP2) in leukemia patients undergoing HSCT. At TP2, there was a significant improvement in PHQ-9 (p = 0.001), MOCA (p < 0.0001), functional scale (p < 0.0001) and global health & QoL scale (p = 0.001) of EORTC QLQ C30 scores whereas there was a significant decrease in symptom scale of EORTC QLQ C30 score (p = 0.005). Furthermore, at TP2 a statistically significant (p < 0.05) negative correlation was observed between MOCA and symptom scale of EORTC QLQ C30 after Pearson correlation analysis. In conclusion, post-30 days of HSCT there was alleviation in depressive behavior, cognition, and QoL in leukemia patients compared to before therapy.

Graphical abstract

Beneficial effect and mechanism of natural resourced polysaccharides on regulating bone metabolism through intestinal flora: A review

Bone metabolism is an important biological process for maintaining bone health. Polysaccharides of natural origin exert beneficial effects on bone metabolism. Polysaccharide molecules often have difficulty passing through the intestinal cell membrane and are directly absorbed in the gastrointestinal tract. Therefore, polysaccharides may affect intestinal flora and play a role in disease treatment. We performed a comprehensive review of the relevant literature published from 2003 to 2023. We found that several polysaccharides from traditional Chinese medicines, including Astragalus, Achyranthes bidentata and Eucommia ulmoides, and the polysaccharides from several dietary fibers mainly composed of inulin, resistant starch, and dextran could enrich the intestinal microbiota group to regulate bone metabolism. The promotion of polysaccharide decomposition by regulating the Bacteroides phylum is particularly critical. Studies on the structure-activity relationship showed that molecular weight, glycosidic bonds, and monosaccharide composition may affect the ability of polysaccharides. The mechanism by which polysaccharides regulate intestinal flora to enhance bone metabolism may be related to the regulation of short-chain fatty acids, immunity, and hormones, involving some signaling pathways, such as TGF-β, Wnt/β-catenin, BMP/Smads, and RANKL. This paper provides a useful reference for the study of polysaccharides and suggests their potential application in the treatment of bone metabolic disorders.

Effect of romosozumab in premenopausal women with severe osteoporosis and anorexia nervosa

Objectives

This study aims to investigate the effects of romosozumab on bone mineral density (BMD) and bone metabolism.

Methods

In this retrospective case series, romosozumab was administered to 5 premenopausal female patients with osteoporosis and anorexia nervosa with fragility fractures. BMD and bone turnover marker changes were investigated at 6 months and 1 year after administering romosozumab.

Results

BMD increased and high-turnover bone metabolism decreased 6 months and 1 year after administering romosozumab.

Conclusions

Romosozumab is useful for treating osteoporosis in patients with anorexia nervosa.

Serum levels of bone turnover markers including calculation of Z-scores: Data from a Dutch healthy reference cohort

Introduction

Bone turnover markers (BTM) are biochemical compounds reflecting different stages of bone metabolism. Their levels change with age and differ between males and females. This makes clinical interpretation and comparison more difficult. Therefore, our aim was to establish BTM reference values which can be used to calculate Z-scores for use in daily clinical practice.

Methods

Serum markers of collagen resorption, bone formation/regulation, collagen formation and bone mineralization (sCTX, OC, PINP and BALP, respectively) were measured in non-fasting volunteers without bone-related abnormalities. Raw data was plotted and gender-specific age cohorts were established with their respective means and standard deviations (SD). Z-scores can be calculated using these reference values to correct for the influence of age and gender on BTM.

Results

In total, 856 individuals were included of which 486 (57 %) were female. Individuals were aged between 7 and 70 years. Highest serum levels of BTM were found in childhood and puberty. Peak levels are higher in boys than girls and prevail at later ages. In adults, BTM levels decrease before reaching stable nadir levels. In adults, 10-year reference cohorts with means and SD were provided to calculate Z-scores.

Conclusion

With our data, Z-scores of sCTX, OC, PINP and BALP can be calculated using reference categories (for age and gender) of Caucasian healthy volunteers. Clinicians can use BTM Z-scores to determine whether there are changes in bone turnover physiology beyond those expected during aging. BTM Z-scores facilitate harmonization of data interpretation in daily clinical practice and research.

Gremlin-1 in pregnancy and postpartum: relation to the fatty liver index, markers of bone health, glucose metabolism and gestational diabetes mellitus status

INTRODUCTION

Gremlin-1 is a peptide that functions as an antagonist to bone morphogenic proteins and is overexpressed in obesity and type 2 diabetes mellitus. Gremlin-1 has not yet been investigated in pregnancy, pregnancy-related insulin resistance or gestational diabetes mellitus (GDM).

PATIENTS AND METHODS

Gremlin-1 levels were measured throughout the pregnancy of 58 women at high risk for GDM at the Medical University of Vienna. Furthermore, an oral glucose tolerance test, fasting insulin, fasting glucose, sex hormones, blood lipids, liver and renal parameters, and markers of bone development were evaluated at two points during pregnancy (< 20 weeks of gestation (GW), GW 24-28) and 12-14 weeks postpartum.

RESULTS

Gremlin-1 levels decreased from < 20 GW (mean = 9.2 pg/ml, SD = 8.4 pg/ml) to GW 24-28 (mean = 6.7 pg/ml, SD = 5.7 pg/ml, p = 0.033) and increased again postpartum, albeit not significantly (mean = 10.7 pg/ml, SD = 13.1 pg/ml, p = 0.339). During pregnancy, Gremlin-1 levels correlated negatively with osteocalcin and procollagen type I aminoterminal propeptide (P1NP), markers of bone health. Concerning glucose metabolism, Gremlin-1 levels were inversely related to the Insulinogenic Index at GW < 20. However, Gremlin-1 levels were not significantly different between women with normal glucose tolerance and GDM during pregnancy. Postpartum, Gremlin-1 was associated with the fatty liver index, osteocalcin levels, diastolic blood pressure and weight.

CONCLUSION

Gremlin-1 levels decreased significantly during pregnancy. The biomarker is not related to GDM status, but correlates negatively with the Insulinogenic Index, an index related to beta cell function. Trial Registry Number ACTRN12616000924459.

SIRT1 Asn346 sugar chain promoting collagen deacetylation protective effect on osteoblasts under stress

Silencing type information regulator homolog 1 (SIRT1) is a class of nicotinamide adenine dinucleotide (NAD+) dependent deacetylases, which is the convergence point of important physiological processes in vivo, namely, osteoblast aging, energy metabolism, and bone remodeling. To verify whether the O-acetylglucosamine (O-GlcNAc) modification of SIRT1 in the nucleus of osteoblasts enhances its deacetylase activity under stress and protects osteoblasts through the RANK/RANKL signaling pathway by collagen deacetylation. The R language and online data research identified SIRT1 as being involved in bone metabolism. Enrichment analysis showed that SIRT1 is involved in osteoblast transcription, apoptosis, and deacetylation pathways. Interactive Immuno-blotting and immunofluorescence experiments revealed that SIRT1 and O-glycosylation catalytic enzyme (OGT) were localized in the nucleus. Mass Spectrometry analysis showed that O-glycosylation occurred on the asparagine at the 346th position of SIRT1, and N346th was located in the central domain of SIRT1. Furthermore, the protein structure analysis of PyMol also proved that the OGT binding region was in the central domain of SIRT1. Under physiological conditions, both wtSIRT1 and SIRT1N346R can inhibit RANKL-mediated transcriptional activation. The RT-PCR detection results showed that wtSIRT1 reduced RANKL transcription under the conditions of apoptotic agent treatment. The finding that SIRT1 can regulate the physiological process of bone remodeling through the RANK/RANKL signaling pathway in osteoblasts under stress. The O-glycosylation and deacetylation activity of SIRT1 significantly increased, regulating the balance between osteoblast survival and apoptosis by deacetylation of key proteins such as RANKL.

Moderate static magnetic field promotes fracture healing and regulates iron metabolism in mice

BACKGROUND

Fractures are the most common orthopedic diseases. It is known that static magnetic fields (SMFs) can contribute to the maintenance of bone health. However, the effect and mechanism of SMFs on fracture is still unclear. This study is aim to investigate the effect of moderate static magnetic fields (MMFs) on bone structure and metabolism during fracture healing.

METHODS

Eight-week-old male C57BL/6J mice were subjected to a unilateral open transverse tibial fracture, and following treatment under geomagnetic field (GMF) or MMF. The micro-computed tomography (Micro-CT) and three-point bending were employed to evaluate the microarchitecture and mechanical properties. Endochondral ossification and bone remodeling were evaluated by bone histomorphometric and serum biochemical assay. In addition, the atomic absorption spectroscopy and ELISA were utilized to examine the influence of MMF exposure on iron metabolism in mice.

RESULTS

MMF exposure increased bone mineral density (BMD), bone volume per tissue volume (BV/TV), mechanical properties, and proportion of mineralized bone matrix of the callus during fracture healing. MMF exposure reduced the proportion of cartilage in the callus area during fracture healing. Meanwhile, MMF exposure increased the number of osteoblasts in callus on the 14th day, and reduced the number of osteoclasts on the 28th day of fracture healing. Furthermore, MMF exposure increased PINP and OCN levels, and reduced the TRAP-5b and β-CTX levels in serum. It was also observed that MMF exposure reduced the iron content in the liver and callus, as well as serum ferritin levels while elevating the serum hepcidin concentration.

CONCLUSIONS

MMF exposure could accelerate fracture healing via promote the endochondral ossification and bone formation while regulating systemic iron metabolism during fracture healing. This study suggests that MMF may have the potential to become a form of physical therapy for fractures.

Chinese medicine Gushukang capsule for treating primary osteoporosis: a systematic review and meta-analysis

OBJECTIVE

To systematically evaluate the efficacy and safety of Gushukang (GSK) capsules in the treatment of primary osteoporosis.

METHODS

Randomized controlled trials related to the treatment of primary osteoporosis were collected through online retrieval of the China National Knowledge Infrastructure (CNKI), Wanfang database, Chinese Biomedical Literature Database (Sino-Med), VIP, US National Library of Medicine (PubMed), Web of Science and Cochrane library. The literature was searched from January 1, 2000, to March 17, 2022. The risk bias and quality of the trials included in the meta-analysis were evaluated with the Cochrane Collaboration's risk assessment tool. The effect size was expressed as risk ratios (RRs) or mean differences (MDs) with 95% confidence intervals (CIs).

RESULTS

A total of 24 randomized controlled clinical trials (RCTs) were incorporated into this systematic review. The 2363 patients were all primary osteoporosis patients, of whom 1197 were in the observation group and 1166 were in the control group. GSK capsule group was superior to conventional medication group in improving beta type I collagen carboxy-terminal peptide (β-CTX) (MD - 0.28, 95% CI [- 0.31, - 0.25]), while in improving prepeptide of type I procollagen (PINP), conventional medications group was superior to GSK capsule group (MD - 1.37, 95% CI [- 1.92, - 0.82]), and there were no significant differences between the two groups in overall efficacy (OE) (OR 1.62, 95% CI [0.89, 2.98]), increase of bone mineral density (BMD) (lumbar spine: MD - 0.02, 95% CI [- 0.08, 0.04]; femoral neck: MD - 0.01, 95% CI [- 0.07, 0.05]; hip: MD 0.01, 95% CI [- 0.02, 0.02]), enhancement of alkaline phosphatase (ALP) (MD - 1.37, 95% CI [- 13.29, 10.55]), serum calcium (S-Ca) (MD 0.02, 95% CI [- 0.13, 0.17]), bone glutamyl protein (BGP) (MD 3.75, 95% CI [- 12.26, 19.76]), safety (OR 0.37, 95% CI [0.07, 2.02]) and pain relief (MD 0.32, 95% CI [- 0.59, 1.22]). GSK capsule combined with conventional medications group was superior to conventional medications group in improvement of OE (OR 3.19, 95% CI [2.20, 4.63]), BMD (lumbar spine (MD 0.06, 95% CI [0.02, 0.10]), femoral neck (MD 0.08, 95% CI [0.03, 0.13]), hip (MD 0.14, 95% CI [0.08, 0.21]) and other parts (MD 0.04, 95% CI [0.03, 0.05]), ALP (MD - 5.56, 95% CI [- 10.08, - 1.04]), β-CTX (MD - 0.15, 95% CI [- 0.18, - 0.12]) and pain relief (MD - 1.25, 95% CI [- 1.83, - 0.68]), but there was no difference in S-Ca (MD 0.02, 95% CI [- 0.13, 0.17]), BGP (MD 1.30, 95% CI [- 0.29, 2.89]), PINP (MD 1.30, 95% CI [- 0.29, 2.89]), serum phosphorus (S-P) (MD 0.01, 95% CI [- 0.09, 0.12]) and safety (OR 0.71, 95% CI [0.38, 1.35]).

CONCLUSION

GSK capsules can effectively treat primary osteoporosis, and when combined with conventional medications, the drug significantly increased bone mineral density, relieved pain and improved bone metabolism-related indicators in primary osteoporosis patients with better efficacy. However, due to the inclusion of Chinese literature and possible publication bias, the reliability of conclusions still requires more high-quality RCTs to enhance.

Genetic polymorphisms of rs73620203 in the transforming growth interacting factor gene associated with rheumatoid arthritis in a Chinese population

OBJECTIVE

To explore the association of single nucleotide polymorphisms (SNPs) in the transforming growth interacting factor (TGIF) gene with bone metabolism markers and rheumatoid arthritis (RA) susceptibility.

METHODS

Three SNPs were genotyped in 155 RA patients and 168 healthy controls using high-resolution melting (HRM) analysis. The serum levels of osteocalcin, bone alkaline phosphatase (BALP), and β type I collagen-crosslinked C telopeptide (β-CTX) were detected using electrochemical luminescence in 108 patients randomly selected from the RA group.

RESULTS

Genotype and allele frequency analysis showed that rs73620203 was associated with bone erosion in RA (P = 0.012 and P = 0.003, respectively), and individuals carrying the T allele for rs73620203 showed a decreased RA risk (OR = 0.59, 95% CI = 0.42-0.84; P = 0.003). In sex-specific analysis, the rs73620203 polymorphism was associated with susceptibility to RA in women (P = 0.022 and P = 0.006, respectively). In addition, RA patients with three genotypes at the rs73620203 locus showed significant differences in serum osteocalcin and BALP (P = 0.006 and P = 0.037, respectively). Haplotype analysis revealed that the haploid ATG and GCA frequencies were significantly lower in the RA group (P = 0.036, OR = 0.693; P = 0.002, OR = 0.189, respectively), while the haploid ACA frequency of the RA group was enhanced (P < 0.01, OR = 5.058).

CONCLUSION

Our study provides the first evidence that rs73620203 is associated with RA susceptibility and the relationship between TGIF gene SNPs and the regulation of bone metabolism in RA patients.

The skeletal safety of milk-derived proteins: A meta-analysis of randomized controlled trials

PURPOSE

There has been a persistent claim that dairy products contain calcium-leaching proteins, although the soundness of such a claim has been challenged. A meta-analysis of randomized controlled trials (RCTs) on the effects of milk-derived protein supplementation on bone health indices in adults was performed to reconcile the controversy surrounding the potential skeletal safety concerns of proteins of dairy origin.

METHODS

The PubMed and Web of Science databases were searched for relevant RCTs. A random-effects model was used to generate pooled effect sizes and 95% confidence intervals.

RESULTS

Milk-derived protein supplementation did not significantly affect whole-body BMD (n = 7 RCTs) and BMD at the lumbar spine (n = 10), hip (n = 8), femoral neck (n = 9), trochanter (n = 5), intertrochanter (n = 2), and ultradistal radius (n = 2). The concentrations of bone formation markers (bone-specific alkaline phosphatase [n = 11], osteocalcin [n = 6], procollagen type 1 amino-terminal propeptide [n = 5]), bone resorption markers (N-terminal telopeptide of type 1 collagen [n = 7], C-terminal telopeptide of type 1 collagen [n = 7], deoxypyridinoline [n = 4]), and parathyroid hormone (n = 7) were not significantly affected. However, increased insulin-like growth factor-1 (IGF-1) concentrations (n = 13) were observed. Reduced IGF-1 concentrations were observed when soy protein was used as a comparator, and increased IGF-1 concentrations were observed when carbohydrate was used.

CONCLUSION

Our findings do not support the claim that proteins of dairy origin are detrimental to bone health.

Long-term trajectories of bone metabolism parameters and bone mineral density (BMD) in obese patients treated with metabolic surgery: a real-world, retrospective study

PURPOSE

Potential negative effects of metabolic surgery on skeletal integrity remain a concern, since long-term data of different surgical approaches are poor. This study aimed to describe changes in bone metabolism in subjects with obesity undergoing both Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).

METHODS

A single center, retrospective, observational clinical study on real-world data was performed enrolling subjects undergoing metabolic surgery.

RESULTS

123 subjects were enrolled (males 31: females 92; ages 48.2 ± 7.9 years). All patients were evaluated until 16.9 ± 8.1 months after surgery, while a small group was evaluated up to 4.5 years. All patients were treated after surgery with calcium and vitamin D integration. Both calcium and phosphate serum levels significantly increased after metabolic surgery and remained stable during follow-up. These trends did not differ between RYGB and SG (p = 0.245). Ca/P ratio decreased after surgery compared to baseline (p < 0.001) and this decrease remained among follow-up visits. While 24-h urinary calcium remained stable across all visits, 24-h urinary phosphate showed lower levels after surgery (p = 0.014), also according to surgery technique. Parathyroid hormone decreased (p < 0.001) and both vitamin D (p < 0.001) and C-terminal telopeptide of type I collagen (p = 0.001) increased after surgery.

CONCLUSION

We demonstrated that calcium and phosphorous metabolism shows slight modification even after several years since metabolic surgery, irrespective of calcium and vitamin D supplementation. This different set point is characterized by a phosphate serum levels increase, together with a persistent bone loss, suggesting that supplementation alone may not ensure the maintenance of bone health in these patients.

Estrogen deficiency induces bone loss through the gut microbiota

Postmenopausal osteoporosis is a common bone metabolic disease, and gut microbiota (GM) imbalance plays an important role in the development of metabolic bone disease. Here, we show that ovariectomized mice had high levels of lipopolysaccharide in serum and gut microbiota dysbiosis through increases in luminal Firmicutes:Bacteroidetes ratio. We depleted the GM through antibiotic treatment and observed improvements in bone mass, bone microstructure, and bone strength in ovariectomized mice. Conversely, transplantation of GM adapted to ovariectomy induced bone loss. However, GM depletion reversed ovariectomy-induced gene expression in the tibia and increased periosteal bone formation. Furthermore, bioinformatics analysis revealed that the G-protein-coupled bile acid receptor (TGR5) and systemic inflammatory factors play key roles in bone metabolism. Silencing TGR5 expression through small interfering RNA (siRNA) in the local tibia and knockout of TGR5 attenuated the effects of GM depletion in ovariectomized mice, confirming these findings. Thus, this study highlights the critical role of the GM in inducing bone loss in ovariectomized mice and suggests that targeting TGR5 within the GM may have therapeutic potential for postmenopausal osteoporosis.

Nrf2 differentially regulates osteoclast and osteoblast differentiation for bone homeostasis

Nuclear factor erythroid-derived factor 2-related factor 2 (Nrf2) is a master regulator of antioxidant response and protects cells from excessive oxidative stress. Nrf2 emerges as a prospective therapeutic target for metabolic bone disorders, in which the balance between osteoblastic bone formation and osteoclastic bone resorption is disrupted. However, the molecular mechanism through which Nrf2 modulates bone homeostasis remains unclear. In this study, we compared the differences in Nrf2-mediated antioxidant response and ROS regulation in osteoblasts and osteoclasts, both in vitro and in vivo. Findings indicated a close connection between the Nrf2 expression and its related antioxidant response with osteoclasts than osteoblasts. We next pharmacologically manipulated the Nrf2-mediated antioxidant response during osteoclast or osteoblast differentiation. Nrf2 inhibition enhanced osteoclastogenesis, while its activation suppressed it. In contrast, osteogenesis decreased irrespective of whether Nrf2 was inhibited or activated. These findings highlight the distinct ways in which the Nrf2-mediated antioxidant response regulates osteoclast and osteoblast differentiation, thereby contributing to the development of Nrf2 targeted therapies for metabolic bone diseases.

Calcium supplementation and body mass index modify associations between prenatal phthalate exposure and perinatal bone ultrasound measures among pregnant women

Phthalates have endocrine activity that may interfere with bone health, particularly during pregnancy and the early postpartum period, when bone resorption increases. We evaluated associations between prenatal phthalate exposure and perinatal bone health among 289 mothers in the ELEMENT birth cohort in Mexico City who were randomized upon recruitment to receive 1,200 mg daily calcium supplementation or placebo throughout pregnancy. Spot urine samples at up to three timepoints during pregnancy were assayed for 9 phthalate metabolites. Bone integrity was assessed by quantitative ultrasound speed of sound (SOS) measurements of the phalange and distal radius at 3, 6, and 8 months of pregnancy and 1, 3, 7, and 12 months postpartum. Geometric means of specific gravity-corrected phthalate concentrations were used as overall measures of prenatal exposure. Linear mixed effect models estimated associations between phthalate exposure and repeated perinatal bone SOS measures, adjusting for age, pre-pregnancy body mass index (BMI), education, parity, calcium supplementation, and month of pregnancy/postpartum. Effect modification by calcium supplementation and BMI were assessed in sensitivity analyses. An interquartile range increase in MEP and MiBP increased pregnancy phalange z-scores (β: 0.11; 95%CI: 0.003, 0.31 and β: 0.15; 95%CI: 0.00,0.42, respectively). Higher concentrations of several phthalate metabolites resulted in lower SOS measures among women who received calcium supplements (compared to placebo group) but higher SOS measures among women with a BMI≥25 (compared to BMI<25). These results suggest that phthalate exposure may interfere with bone remodeling during pregnancy, and that consideration of effect modifiers is paramount to fully understand the effects of environmental exposures on bone health.

Biological effects of IL-33/ST2 axis on oral diseases: autoimmune diseases and periodontal diseases

IL-33 is a relatively new member of the IL-1 cytokine family, which plays a unique role in autoimmune diseases, particularly some oral diseases dominated by immune factors. The IL-33/ST2 axis is the main pathway by which IL-33 signals affect downstream cells to produce an inflammatory response or tissue repair. As a newly discovered pro-inflammatory cytokine, IL-33 can participate in the pathogenesis of autoimmune oral diseases such as Sjogren's syndrome and Behcet's disease. Moreover, the IL-33/ST2 axis also recruits and activates mast cells in periodontitis, producing inflammatory chemokines and mediating gingival inflammation and alveolar bone destruction. Interestingly, the high expression of IL-33 in the alveolar bone, which exhibits anti-osteoclast effects under appropriate mechanical loading, also confirms its dual role of destruction and repair in an immune-mediated periodontal environment. This study reviewed the biological effects of IL-33 in autoimmune oral diseases, periodontitis and periodontal bone metabolism, and elaborated its potential role and impact as a disease enhancer or a repair factor.

A review of tamoxifen administration regimen optimization for Cre/loxp system in mouse bone study

Gene knockout is a technique routinely used in basic experimental research, particularly in mouse skeletal and developmental studies. Tamoxifen-induced Cre/loxp system is known for its temporal and spatial precision and commonly utilized by researchers. However, tamoxifen has been shown its side effects on affecting the phenotype of mouse bone directly. This review aimed to optimize tamoxifen administration regimens including its dosage and duration, to identify an optimal induction strategy that minimizes potential side effects while maintaining recombination efficacy. This study will help researchers in designing gene knockout experiments in bone when using tamoxifen.

Suppression of TLR4 prevents diabetic bone loss by regulating FTO-mediated m6A modification

Toll-like receptor-4 (TLR4) has been implicated in the development and progression of diabetic osteoporosis. However, the mechanisms underlying TLR4-regulated bone metabolism in diabetes are yet to be fully understood. Epigenetic modifications have been indicated as a possible mechanism leading to increased risk of osteoporosis and bone fracture. As N6-methyladenosine (m6A) is the most common epigenetic modification in eukaryotic mRNAs, we hypothesized that TLR4 regulates m6A modification in bone tissues of diabetic rats, thereby potentially explaining the pathogenesis of diabetic bone loss. m6A sequencing (m6A-seq) was performed in samples of the femur of TLR4-wild type (TLR4WT) and TLR4-knockout (TLR4KO) diabetic rats to identify genes with differential m6A modifications that may be associated with the bone loss phenotype. We found that in TLR4KO rats, the rapid weight loss of diabetic rats was prevented, and bone mineral density (BMD) was significantly increased. m6A-seq and Gene Ontology enrichment analysis revealed that m6A-modified genes in the femur of TLR4KO diabetic rats were associated with regulation of biological processes such as osteoclast differentiation. qRT-PCR analysis on the expression levels of the m6A-modified methyltransferases and demethylases demonstrated that only the m6A demethylase fat mass and obesity-associated protein（FTO）was decreased. Using an osteoclast cell model, we confirmed that TLR4-mediated osteoclast differentiation was induced by glycolipid toxicity via inhibition of FTO expression. Taken together, these results suggest that inhibition of TLR4 may prevent diabetic bone loss via regulation of FTO-mediated m6A modification.

Assessment of Bone Microarchitecture in Patients with Systemic Mastocytosis and its Association with Clinical and Biochemical Parameters of the Disease

Patients with systemic mastocytosis (SM) are at high risk of bone deterioration. However, the evaluation of bone microarchitecture in this disease remains unclear. We aimed to assess bone microarchitecture in patients with SM. This was a cross-sectional study of 21 adult patients with SM conducted in a quaternary referral hospital in Sao Paulo, Brazil. A healthy, age-, weight-, and sex-matched cohort of 63 participants was used to provide reference values for bone microarchitecture, assessed by high resolution peripheral quantitative computed tomography (HR-pQCT). Total volumetric bone mineral density (vBMD), cortical vBMD, and cortical thickness at the radius were significantly lower in the control group compared with the SM group (all P < 0.001). Patients with aggressive SM had significantly lower trabecular number (Tb.N) (P = 0.035) and estimated failure load (F.load) (P = 0.032) at the tibia compared with those with indolent SM. Handgrip strength was significantly higher in patients who had more Tb.N at the radius (ρ, 0.46; P = 0.036) and tibia (ρ, 0.49; P = 0.002), and lower who had more trabecular separation at the radius (ρ, -0.46; P = 0.035) and tibia (ρ, -0.52; P = 0.016). Strong and positive associations between F.load (ρ, 0.75; P < 0.001) and stiffness (ρ, 0.70; P < 0.001) at the radius, and between F.load at the tibia (ρ, 0.45; P = 0.038) were observed with handgrip strength. In this cross-sectional study, aggressive SM was more susceptible to bone deterioration compared with indolent SM. In addition, the findings demonstrated that handgrip strength was associated with bone microarchitecture and bone strength.

Study on the association of the microstructure and bone metabolism in the osteoporotic femoral head

BACKGROUND

We compared the bone microstructure and metabolism of the femoral heads in patients with osteoporosis (OP) and non-OP patients to investigate the pathologic mechanism of OP and guide clinical treatment.

METHODS AND RESULTS

From January 2020 to June 2021, we obtained femoral head samples from 30 patients undergoing hip replacement due to femoral neck fracture. All patients were women aged approximately 67 to 80 years (mean age, 74 years). According to the dual-energy X-ray results, the femoral head samples were divided into the OP (T< - 2.5) and non-OP (T > - 1.5) groups. Microcomputed tomography scanning, bone metrology analysis, hematoxylin and eosin staining, and Masson's trichrome staining were used to compare the local bone trabecular microstructure changes. Quantitative reverse transcription PCR was performed to identify changes in the osteogenesis-related genes and the osteoclast-related genes in specific regions to reflect osteogenic and osteoclastic activities. Femoral heads with OP showed significant changes in the local bone microstructure. Bone density, bone volume fraction, and the number and thickness of the bone trabeculae decreased. Local bone metabolism was imbalanced in the areas with microstructural changes in femoral heads with OP, with increased osteoclast activity and decreased osteoblast activity.

CONCLUSIONS

Deterioration of bone microstructure is closely related to abnormal bone metabolism associated with the activity of osteoblasts and osteoclasts in osteoporotic femoral heads. Promoting bone formation by improving local bone metabolism, enhancing osteogenic activity and inhibiting osteoclast activity may be a promising way of preventing local OP and osteoporotic fractures.

Regulation of cholesterol homeostasis in osteoporosis mechanisms and therapeutics

Osteoporosis is a metabolic bone disease that affects hundreds of millions of people worldwide and is characterized by excessive loss of bone protein and mineral content. The incidence and mortality of osteoporosis increase with age, creating a significant medical and economic burden globally. The importance of cholesterol levels has been reported in the development of diseases including osteoporosis. It is important to note that key enzymes and molecules involved in cholesterol homeostasis are closely related to bone formation. Excessive cholesterol may cause osteoporosis, cholesterol and its metabolites affect bone homeostasis by regulating the proliferation and stimulation of osteoblasts and osteoclasts. Therefore, antagonism of elevated cholesterol levels may be a potential strategy to prevent osteoporosis. There is sufficient evidence to support the use of bisphosphonates and statin drugs for osteoporosis in the clinic. Therefore, in view of the aggravation of the aging problem, we summarize the intracellular mechanism of cholesterol homeostasis and its relationship with osteoporosis (including cholesterol and cholesterol oxidation products (COPs) in osteoporosis). Furthermore, the current clinical cholesterol-lowering drugs for osteoporosis were also summarized, as are new and promising therapies (cell-based therapies (e.g., stem cells) and biomaterial-delivered target drug therapies for osteoporosis as well).