From estrogen-centric to aging and oxidative stress: a revised perspective of the pathogenesis of osteoporosis

Manganese dioxide coupled metal-organic framework as mitophagy regulator alleviates periodontitis through SIRT1-FOXO3-BNIP3 signaling axis

Periodontitis is a prevalent chronic inflammatory disease characterized by alveolar bone resorption. Its progression is closely linked to oxidative stress where reactive oxygen species (ROS) generated by mitochondria exacerbate inflammation in positive feedback loops. Strategies for mitochondrial regulation hold potential for therapeutic advances. Metal-organic frameworks (MOFs) have shown promise as nanozymes for ROS scavenging. However, inability to directly regulate cellular processes to prevent further ROS production from damaged mitochondria during persistent inflammation makes MOFs insufficient in treating periodontitis. This study synthesizes MnO2@UiO-66(Ce) by introducing MnO2 within nanoscale mesoporous UiO-66 type MOFs. MnO2 coupled with Ce clusters in MOF channels, forms a superoxide dismutase/catalase cascade catalytic system. More importantnly, manganese endows the MOFs with bioactive effects which enhances mitophagy, facilitating the removal of damaged mitochondria, thereby restoring long-term cellular homeostasis. The results demonstrate that this synergistic antioxidant solution MnO2@UiO-66 restores mitochondrial homeostasis and osteogenic activity of periodontal ligament cells in vitro and alleviates inflammatory bone resorption in a ligature-induced periodontitis model in vivo. The SIRT1-FOXO3-BNIP3 signaling axis plays a key role in this process. This study may provide a design strategy that combines a highly efficient cascade catalytic system with long-term regulation of cellular homeostasis to combat oxidative stress in chronic inflammation.

ED-71 ameliorates OVX-induced osteoporosis by regulating calcium homeostasis and SIRT1-mediated mitochondrial function, alleviating osteoblast senescence and suppressing osteoclastogenesis

Osteoporosis arising from estrogen deficiency is characterized by oxidative stress and cellular senescence accompanied by calcium loss and disrupted bone metabolism. The paracrine interaction between osteoblasts and osteoclasts, along with the ratio of receptor activator of nuclear factor-κB ligand (RANKL) to osteoprotegerin (OPG), play a pivotal role in maintaining bone homeostasis. Eldecalcitol (ED-71), a novel active form of vitamin D, can reduce the ratio of RANKL to OPG in osteoblasts. In this study, an ovariectomized (OVX) rat model was established in vivo, and a cell model was constructed in vitro using H₂O₂ to explore the specific mechanism by which ED-71 improved the release of RANKL/OPG in senescent osteoblasts. Mitochondrial dysfunction and calcium imbalance were identified as significant factors. Under oxidative stress conditions, ED-71 alleviated endoplasmic reticulum (ER) stress by decreasing the ratio of phosphorylated protein kinase R-like ER kinase (P-PERK/PERK), and augmented the expression levels of sarcoplasmic reticulum/endoplasmic reticulum calcium ATPase 2 (SCERA2) thereby promoting calcium uptake by the ER, enhancing ER calcium influx, and effectively ameliorating calcium homeostasis between the ER and mitochondria. Consequently, it mitigates mitochondrial calcium overload and associated dysfunction. In contrast, ED-71 increased the expression of silent information regulator 1 (SIRT1) and phosphorylated AMP-activated protein kinase (P-AMPK). This alleviates mitochondrial dysfunction and promotes adenosine triphosphate (ATP). The combined effects of these two factors synergistically contribute to the improvement in osteoblast senescence.

Relationships among osteoporosis, redox homeostasis, and alcohol addiction: Importance of the brain-bone axis

Overabundance of reactive oxygen species (oxidative distress) leads to redox homeostasis disturbance and is associated with many pathological conditions. Accumulating evidence suggests that oxidative distress may contribute to osteoporosis. This review thoroughly outlines the relationships among osteoporosis, redox homeostasis, and alcohol addiction, since these relations are not sufficiently known and subsequently summarized. The brain-bone axis plays a crucial role in alcohol-induced damage to the nervous and skeletal systems. Alterations in the nervous system can lead to osteoporosis because the central nervous system is involved in bone remodeling through various neural pathways. Conversely, as an endocrine organ, bone secretes a number of bone-derived factors (osteokines), which can influence brain function and behavior. As a result, osteoporosis is more common in individuals with neurological disorders, and sudden neurological events can rapidly increase the risk of osteoporosis. Excessive alcohol consumption is linked to many neurological complications, as well as osteoporosis, which are manifested by disrupted redox homeostasis, inflammation, neurodegeneration, inhibition of neurogenesis, decreased bone mineral density, impaired bone microarchitecture, altered mineral homeostasis, raising fracture risk, hormonal dysregulation, and altered gut microbiota composition. Compared to men, alcohol dependence has more negative consequences for women, including an increased risk of liver, cardiovascular, metabolic, mental disorders, and breast cancer. Abstinence has been demonstrated to improve bone and brain health in alcohol addiction. The discovery of the brain-bone axis may lead to the development of new therapeutic approaches for alcohol and other substance addictions. Further research is needed in this direction, as many questions remain unanswered.

RANKL promotes MT2 degradation and ROS production in osteoclast precursors through Beclin1-dependent autophagy

ROS produced under oxidative stress are crucial for osteoclast differentiation. Metallothionein (MT) is a ROS-scavenging molecule. As a member of MT family, MT2 can clear ROS in osteoclast precursors (OCPs) and contributes to osteoclast differentiation. RANKL can promote OCP autophagy. Given the molecular-degrading effect of autophagy, the relationship between RANKL-dependent autophagy, MT2 and ROS during osteoclast differentiation is worth exploring. We depended in vitro RANKL administration and RANKL-overexpressing (Tg-RANKL) mice to observe the effects of RANKL on ROS production, MT2 protein expression, Beclin1 expression and autophagic activity in OCPs. Spautin1 was used to investigate the relationship between Beclin1-dependent autophagy and RANKL-regulated MT2 expression. Osteoclast-targeting MT2-cDNA-AAVs were applied to assess the therapeutic effect of MT2 on Tg-RANKL-related bone loss. The results showed that RANKL promoted ROS production but reduced MT2 protein expression in OCPs. RANKL also enhanced Beclin1 expression and LC3-puncta abundance. Decreased Beclin1 expression with spautin1 blocked RANKL-increased ROS production and osteoclast differentiation and recovered RANKL-decreased MT2 expression. MT2 selective overexpression with CD11b-promoter-MT2-cDNA-AAVs attenuated ROS production and osteoclastogenesis in Tg-RANKL mice and improved bone loss. Overall, RANKL can reduce MT2 protein expression through Beclin1-dependent autophagy, thereby promoting ROS production and osteoclast differentiation; this suggests that MT2-overexpressing small molecule drugs have the potential to treat RANKL-related bone loss.

Mapping the role of macro and micronutrients in bone mineral density: a comprehensive Mendelian randomization study

BACKGROUND

Macro and micronutrients may play an important role in osteoporosis development; however, observational studies have yielded inconsistent results. Clarifying these associations is vital to the development of nutritional recommendations aimed at preventing osteoporosis.

METHODS

Utilizing the largest available genome-wide association study (GWAS) summary statistics to date, we performed a two-sample Mendelian randomization (MR) analysis to investigate the causal effects of energy-adjusted macronutrient intake (fat, protein, carbohydrate, and sugar) and circulating levels of 20 micronutrients (ten each for vitamins and minerals) on heel estimated bone mineral density (eBMD), a promising marker for osteoporosis risk and fracture susceptibility. Sensitivity, sex-specific, and one-sample MR analyses were applied to further validate and annotate the results.

RESULTS

Among all nutrients, four genetically predicted circulating levels of micronutrients were suggestively associated with eBMD (vitamin A: β IVW = - 0.054, PIVW = 3.70 × 10-2; vitamin B12: β IVW = - 0.020, PIVW = 3.71 × 10-6; vitamin E: β IVW = 0.277, PIVW = 3.22 × 10-2; selenium: β IVW = 0.023, PIVW = 5.37 × 10-3; all Pintercept > 0.05). All these results were also considered robust, as sensitivity analyses yielded directionally consistent results. However, only the causal effects of vitamin B12 and selenium on eBMD remained significant after Bonferroni correction and were not confounded by obesity, smoking status, or alcohol consumption. Sex-specific analysis revealed a male-specific causal association between vitamin E and eBMD ( β IVW = 0.275, PIVW = 9.81 × 10-14). Additionally, using individuallevel data from the UK Biobank cohort, one-sample MR analysis found no causal relationships between diet-derived nutrient intake and eBMD in the overall population, as well as in the females or the males.

CONCLUSIONS

Our findings suggest that appropriate levels of plasma vitamin B12 and adequate levels of serum selenium are crucial for delaying bone loss and promoting bone health, emphasizing the need for nutritional recommendations to maintain optimal levels of these nutrients to promote eBMD and prevent osteoporosis.

Medical gas plasma modifies Nrf2 signaling in diabetic wound healing

INTRODUCTION

Diabetes mellitus is a chronic disease that can disrupt physiologic wound healing. Medical gas plasma technology produces therapeutic reactive species that support wound healing.

OBJECTIVE

Previous studies have shown that increasing the transcriptional activity of the redox regulator nuclear factor erythroid 2-related factor 2 (Nrf2) in diabetic models can improve insulin sensitivity, reduce blood glucose levels, and ameliorate diabetic complications. However, the therapeutic potential and mechanisms of action of gas plasma have not been addressed in this context.

METHODS

Full-thickness dermal ear wounds were created in a preclinical mouse model of type II diabetes and compared with a native wild-type strain of C57BL/6 mice. First, the formation of reactive species in the plasma gas phase was determined by optical emission spectroscopy. Second, qPCR, protein expression, and inflammation analysis by cytokine secretion were performed to confirm the transcriptional results. Finally, qPCR and cytokine profiling were conducted to measure the effects of gas plasma in patient wound samples.

RESULTS

Repeated in vivo treatment with medical gas plasma supported wound healing, e.g., re-epithelialization, in both sexes. Gas plasma-stimulated changes in Nrf2 signaling associated with downstream targets were supported by the evidence of impaired wound healing in Nrf2 knockout mice. In addition, gas plasma treatment significantly affected inflammation by modulating local and systemic cytokine levels. In vivo, treatment of human diabetic wounds underscored the involvement of Nrf2 signaling in protecting against oxidative stress, as assessed by qPCR. The cytokine signature of human diabetic wounds outlined different response patterns among patients after a single exposure, while inflammatory mediators were consistently reduced after repeated plasma treatment.

CONCLUSIONS

The present finding of accelerated wound healing by the Nrf2 activator underlines the high potential of medical gas plasma therapy in non-diabetic and diabetic wound healing.

Dnmt3a-mediated hypermethylation of FoxO3 promotes redox imbalance during osteoclastogenesis

Redox imbalance contributes to aberrant osteoclastogenesis and osteoporotic bone loss. In this study, we observed lower Forkhead box protein O3 (FoxO3), a transcription factor associated with cellular oxidative stress, enhanced osteoclastogenesis in osteoporosis (OP). Single-cell RNA sequencing (scRNA-seq) analysis on the human femoral head indicated that FoxO3 is widely expressed in macrophages. Furthermore, Lysm-Cre;FoxO3f/f OVX mice showed increased reactive oxygen species (ROS), enhanced osteoclastogenesis, and more bone loss than normal OVX mice. Mechanistically, we identified FoxO3 promoter methylation as a crucial factor contributing to decreased FoxO3, thereby influencing osteoclastogenesis and OC function. Intriguingly, we observed that Dnmt3a, highly expressed during osteoclastogenesis, played a pivotal role in regulating the methylation of the FoxO3 promoter. Knockdown of Dnmt3a promoted FoxO3 expression, inhibiting osteoclastogenesis and mitigating OP. Interestingly, we observed that Dnmt3a alleviated osteoclastogenesis by suppressing ROS via upregulating FoxO3 rather than inducing the dissociation of RANK and TRAF6. Collectively, this study elucidates the role and mechanism of FoxO3 in osteoclastogenesis and OP, providing a epigenetic target for the treatment of OP.

Mechanisms of mitochondrial reactive oxygen species action in bone mesenchymal cells

Mitochondrial (mt)ROS, insufficient NAD+, and cellular senescence all contribute to the decrease in bone formation with aging. ROS can cause senescence and decrease NAD+, but it remains unknown whether these mechanisms mediate the effects of ROS in vivo. Here, we generated mice lacking the mitochondrial antioxidant enzyme Sod2 in osteoblast lineage cells targeted by Osx1-Cre and showed that Sod2ΔOsx1 mice had low bone mass. Osteoblastic cells from these mice had impaired mitochondrial respiration and attenuated NAD+ levels. Administration of an NAD+ precursor improved mitochondrial function in vitro but failed to rescue the low bone mass of Sod2ΔOsx1 mice. Single-cell RNA-sequencing of bone mesenchymal cells indicated that ROS had no significant effects on markers of senescence but disrupted parathyroid hormone signaling, iron metabolism, and proteostasis. Our data supports the rationale that treatment combinations aimed at decreasing mtROS and senescent cells and increasing NAD+ should confer additive effects in delaying age-associated osteoporosis.

Follicular metabolic dysfunction, oocyte aneuploidy and ovarian aging: a review

With the development of modern society and prolonged education, more women choose to delay their childbearing age, which greatly increases the number of women aged older than 35 years with childbearing needs. However, with increasing age, the quantity and quality of oocytes continue to fall, especially with increasing aneuploidy, which leads to a low in vitro fertilization (IVF) success rate, high abortion rate and high teratogenesis rate in assisted reproduction in women with advanced maternal age. In addition to genetics and epigenetics, follicular metabolism homeostasis is closely related to ovarian aging and oocyte aneuploidy. Glucose, lipid, and amino acid metabolism not only provide energy for follicle genesis but also regulate oocyte development and maturation. This review focuses on the relationships among follicular metabolism, oocyte aneuploidy, and ovarian aging and discusses potential therapeutic metabolites for ovarian aging.

The Effect of Patient-related Factors Age, Sex, Implant Location, and Periodontitis on Crestal Bone Loss in the Posterior Ridge: A Retrospective Study

PURPOSE

To investigate the effects of patient-related factors such as age, sex, implant location, and history of periodontitis, on crestal bone loss in the posterior region throughout the surgical healing and functional periods.

MATERIALS AND METHODS

This study evaluated 311 implants from 163 patients, with an average follow-up of 27.10 months. Implants were assessed based on age, sex, implant location, and history of periodontitis. Crestal bone loss was quantified by measuring bone level changes using oral panoramic radiographs. Time T1 was defined as the period from implant placement to the healing phase, and T2 as the period from the second-stage surgery to the follow-up visit. Group comparisons were made using the Mann-Whitney U-test, with significance set at p 0.05.

RESULT

At T1, crestal bone loss averaged 0.27 ± 0.40 mm; at T2, it averaged 0.40 ± 0.50 mm. A statistically significant difference at T1 was observed between patients aged 20-39 and 40-59, and between these two age groups in female patients (p 0.05). During T2, within the 40-59 age group, bone resorption differed statistically significantly between males and females (p 0.05). Statistically significant differences were also noted between males aged 40-59 and those 60 years or older, and between females aged 20-39 and 40-59 (p 0.05). There were no differences between the other groups.

CONCLUSION

Crestal bone loss correlates with patient age and sex. Increased attention should be given to female patients within certain age ranges. Patients with history of periodontitis can maintain bone tissue stability around the implant.

Versatile hydrogels prepared by microfluidics technology for bone tissue engineering applications

Bone defects are a prevalent issue resulting from various factors, such as trauma, degenerative diseases, congenital disabilities, and the surgical removal of tumors. Current methods for bone regeneration have limitations. In this context, the fusion of tissue engineering and microfluidics has emerged as a promising strategy in the field of bone regeneration. This study describes the classification of microfluidic devices based on the nature of flow and channel type, as well as the materials and techniques required. An overview of microfluidic methods used to prepare hydrogels and the advantages of using these hydrogels in bone tissue engineering (BTE) combining several basic elements of BTE to highlight its advantages is provided. Furthermore, this work emphasizes the benefits of using hydrogels prepared via microfluidics over conventional hydrogels in BTE because of their controlled release of cargo, they can be used for in situ injection, simplify the steps of single-cell encapsulation and have the advantages of high-throughput and precise preparation. Additionally, organ-on-a-chip models fabricated via microfluidics offer a platform for studying cell and tissue behaviors in an authentic and dynamic environment. Moreover, microfluidic devices can be utilized for noninvasive diagnosis and therapy. Finally, this paper summarizes the preclinical and clinical applications of hydrogels prepared via microfluidics for bone regeneration by focusing on their current developmental status, limitations associated with their application, and future challenges, which underscore their potential impacts on advancing regenerative medicine practices.

Rectifying the Crosstalk between the Skeletal and Immune Systems Improves Osteoporosis Treatment by Core-Shell Nanocapsules

Contemporary osteoporosis treatment often neglects the intricate interactions among immune cells, signaling proteins, and cytokines within the osteoporotic microenvironment. Here, we developed core-shell nanocapsules composed of a cationized lactoferrin core and an alendronate polymer shell. By tuning the size of these nanocapsules and leveraging the alendronate shell, we enabled precise delivery of small interfering RNA targeting the Semaphorin 4D gene (siSema4D) to specific bone sites. This strategy integrates the antiresorptive drug alendronate with siSema4D, efficiently inhibiting osteoclast (OC) differentiation and bone resorption, while promoting osteogenesis to restore the balance between osteoblasts (OBs) and OCs. Moreover, encapsulating siSema4D within the nanocapsules helps to mitigate immunological cascades, thereby reversing the inflammatory microenvironment and restoring immune homeostasis and providing insights into the immunomodulatory effects of Sema4D in osteoporosis therapy. In both ovariectomized and senile osteoporotic mouse models, local intramuscular administration of core-shell nanocapsules effectively rectified the imbalance between the skeletal and immune systems, significantly enhancing the overall efficacy of osteoporosis treatment. Our findings underscore the therapeutic promise of addressing the multifaceted osteoporotic microenvironment through targeted interventions.

Methylase METTL3 regulates oxidative stress-induced osteoblast apoptosis through Wnt/β-catenin signaling pathway

The latest research shows that the imbalance of reactive oxygen species (ROS) leads to oxidative stress-induced osteoblast apoptosis, which is an important factor in the development of osteoporosis. Methyltransferase like 3 (METTL3) is the most widely known methyltransferase, which has a marked effect on the cells of oxidative stress reaction. However, the precise mechanism through which METTL3 mediates oxidative stress-induced osteoblast apoptosis remains uncleared. An ovariectomized (OVX) rat model was established and histochemical staining were used to evaluate bone mass and the expression of METTL3. The oxidative stress state of bone tissue and the expression of METTL3 were detected by RT-PCR. The reactive oxygen species (ROS) levels were detected by DCFH-DA staining. Cell death and apoptosis were detected by CCK8, Hoechst PI double dyeing and TUNEL staining. The mitochondrial membrane potential was detected by JC-1 fluorescent staining. The expression of N6-methyladenosine, the protein levels of cell apoptosis and Wnt/β-catenin signal were detected by RT-PCR and western blot. We demonstrated that METTL3 was highly expressed in OVX-induced osteoporosis, and it inhibited oxidative stress-induced apoptosis of MC3T3-E1 cells by downregulating the ROS-mediated activation of the Wnt/β-catenin signaling pathway in osteoblasts. In addition, under oxidative stress, ROS accumulation further inhibited METTL3 expression and activated the Wnt/β-catenin signaling pathway, which ultimately led to apoptosis of MC3T3-E1 cells. This study investigated the important role of METTL3 in oxidative stress-induced osteoblast apoptosis. It may be a new therapeutic target for osteoporosis from the perspective of oxidative stress.

Application and progress of 3D printed biomaterials in osteoporosis

Osteoporosis results from a disruption in skeletal homeostasis caused by an imbalance between bone resorption and bone formation. Conventional treatments, such as pharmaceutical drugs and hormone replacement therapy, often yield suboptimal results and are frequently associated with side effects. Recently, biomaterial-based approaches have gained attention as promising alternatives for managing osteoporosis. This review summarizes the current advancements in 3D-printed biomaterials designed for osteoporosis treatment. The benefits of biomaterial-based approaches compared to traditional systemic drug therapies are discussed. These 3D-printed materials can be broadly categorized based on their functionalities, including promoting osteogenesis, reducing inflammation, exhibiting antioxidant properties, and inhibiting osteoclast activity. 3D printing has the advantages of speed, precision, personalization, etc. It is able to satisfy the requirements of irregular geometry, differentiated composition, and multilayered structure of articular osteochondral scaffolds with boundary layer structure. The limitations of existing biomaterials are critically analyzed and future directions for biomaterial-based therapies are considered.

Regulation of enzymatic lipid peroxidation in osteoblasts protects against postmenopausal osteoporosis

Oxidative stress plays a critical role in postmenopausal osteoporosis, yet its impact on osteoblasts remains underexplored, limiting therapeutic advances. Our study identifies phospholipid peroxidation in osteoblasts as a key feature of postmenopausal osteoporosis. Estrogen regulates the transcription of glutathione peroxidase 4 (GPX4), an enzyme crucial for reducing phospholipid peroxides in osteoblasts. The deficiency of estrogen reduces GPX4 expression and increases phospholipid peroxidation in osteoblasts. Inhibition or knockout of GPX4 impairs osteoblastogenesis, while the elimination of phospholipid peroxides rescues bone formation and mitigates osteoporosis. Mechanistically, 4-hydroxynonenal, an end-product of phospholipid peroxidation, binds to integrin-linked kinase and triggers its protein degradation, disrupting RUNX2 signaling and inhibiting osteoblastogenesis. Importantly, we identified two natural allosteric activators of GPX4, 6- and 8-Gingerols, which promote osteoblastogenesis and demonstrate anti-osteoporotic effects. Our findings highlight the detrimental role of phospholipid peroxidation in osteoblastogenesis and underscore GPX4 as a promising therapeutic target for osteoporosis treatment.

Skeletal interoception and prospective application in biomaterials for bone regeneration

Accumulating research has shed light on the significance of skeletal interoception, in maintaining physiological and metabolic homeostasis related to bone health. This review provides a comprehensive analysis of how skeletal interoception influences bone homeostasis, delving into the complex interplay between the nervous system and skeletal system. One key focus of the review is the role of various factors such as prostaglandin E2 (PGE2) in skeletal health via skeletal interoception. It explores how nerves innervating the bone tissue communicate with the central nervous system to regulate bone remodeling, a process critical for maintaining bone strength and integrity. Additionally, the review highlights the advancements in biomaterials designed to utilize skeletal interoception for enhancing bone regeneration and treatment of bone disorders. These biomaterials, tailored to interact with the body's interoceptive pathways, are positioned at the forefront of innovative treatments for conditions like osteoporosis and fractures. They represent a convergence of bioengineering, neuroscience, and orthopedics, aiming to create more efficient and targeted therapies for bone-related disorders. In conclusion, the review underscores the importance of skeletal interoception in physiological regulation and its potential in developing more effective therapies for bone regeneration. It emphasizes the need for further research to fully understand the mechanisms of skeletal interoception and to harness its therapeutic potential fully.

Sex hormone deficiency in male and female mice expressing the Alzheimer's disease-associated risk-factor TREM2 R47H variant impacts the musculoskeletal system in a sex- and genotype-dependent manner

The R47H variant of the triggering receptor expressed on myeloid cells 2 (TREM2) is a risk factor for Alzheimer's disease in humans and leads to lower bone mass accrual in female but not male 12-mo-old mice. To determine whether, as with aging, gonadectomy results in sex-specific musculoskeletal effects, gonad removal or SHAM surgery was performed in 4-mo-old TREM2R47H/+ mice and WT male and female littermates (n = 10-12/group), with sexes analyzed separately. Body weight was lower in males, but higher in females after gonadectomy, independently of their genotype. Gonadectomy also leads to decreased BMD in males at all sites and in the whole body (total) and spine in female mice for both genotypes. Total and femur BMD was lower in gonadectomized male mice 6-wk post-surgery, independently of the genotype. On the other hand, BMD was only lower in ovariectomized WT but not TREM2R47H/+ mice in all sites measured at this time point. Bone formation and resorption marker levels were not affected by orchiectomy, whereas CTX was higher 3 wk after surgery and P1NP showed a tendency toward lower values at the 6-wk time point only in ovariectomized WT mice. Micro-CT analyses showed no differences resulting from gonadectomy in structural parameters in femoral cortical bone for either sex, but lower tissue mineral density in males of either genotype 6-wk post-surgery. Nevertheless, biomechanical properties were overall lower in gonadectomized males of either genotype, and only for WT ovariectomized mice. Distal femur cancellous bone structure was also affected by gonadectomy in a genotype- and sex-dependent manner, with genotype-independent changes in males, and only in WT female mice. Thus, expression of the TREM2 R47H variant minimally alters the impact of gonadectomy in the musculoskeletal system in males, whereas it partially ameliorates the consequences of ovariectomy in female mice.

4-Hydroxyphenylacetic Acid, a microbial-derived metabolite of Polyphenols, inhibits osteoclastogenesis by inhibiting ROS production

Intracellular reactive oxygen species (ROS) accumulation is key to osteoclast differentiation. Plant-derived polyphenols that have reduced ROS production have been widely studied for the treatment of osteoporosis. However, these compounds are rarely absorbed in the small intestine and are instead converted to phenolic acids by the microbiota in the colon. These large quantities of low-molecular-weight phenolic acids can then be absorbed by the body. 4-Hydroxyphenylacetic acid (4-HPA) is an important metabolite of these polyphenols that is generated by the human intestinal microbiota. However, its potential mechanism is not fully understood. In this study, we aimed to elucidate the role of 4-HPA on osteoclastogenesis and treating osteoporosis. Our study showed that 4-HPA inhibited osteoclast differentiation and function and downregulated osteoclast-specific genes, including NFATc1, Atp6v0d2, MMP9, CTSK, Acp5, and c-Fos. As for further mechanism exploration, 4-HPA reduced ROS accumulation by regulating nuclear factor erythroid 2-related factor (Nrf2) and subsequently inhibited the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. To evaluate the effect of 4-HPA on postmenopausal osteoporosis, an ovariectomized (OVX) mouse model was used. The Micro-CT and histomorphometry analyses showed that 4-HPA effectively prevents bone loss. Encouragingly, 4-HPA demonstrated efficacy in treating osteoporosis induced by OVX. In conclusion, our study revealed that 4-HPA, a polyphenol metabolite produced by intestinal microorganisms, also inhibits osteoclast formation and treats osteoporosis, which provides a new experimental basis and candidate drug for the treatment of osteoporosis.

Integrated analysis of transcriptome and proteome reveals a core set of genes involved in osteoblast under oxidative stress

Osteoblasts dysfunction, induced by oxidative stress (OS), is a significant contributor to the pathogenesis of osteoporosis. However, the genes implicated in regulating osteoblast dysfunction remain unclear. Here, we employed the hydrogen peroxide (H2O2)-induced osteoblast dysfunction model to assess its impact on osteoblast phenotype and to conduct transcriptome and proteome analyses in osteoblasts under OS. We identified 164 genes and 186 proteins with altered expression (differentially expressed genes (DEGs) and differentially expressed proteins (DEPs), respectively). Functional analysis using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways revealed enrichment in pathways associated with apoptosis and osteoblast differentiation. We constructed a protein-protein interaction (PPI) network of DEPs, which comprised 175 DEPs as nodes. Furthermore, seven key DEGs and DEPs with positive correlation (cor-DEGs-DEPs genes) were characterized based on the integrated analysis of mRNA-protein expression. Among these seven genes, Ho-1, Fosl1, and Fosl2 were shown to be upregulated, associated with OS-induced cell differentiation impairment and apoptosis. Conversely, Ccnd2, Col1α1, Col12α1, and Fgfr2 were shown to be downregulated, linked to OS-induced cell cycle delay, apoptosis, impaired mineralization, and differentiation. PPI analysis revealed interactions between these key genes. Lastly, we validated these genes at both mRNA and protein levels using qRT-PCR and Western blot experiments. This study identified seven candidate genes potentially involved in the detrimental effects of OS on MC3T3-E1 apoptosis and dysfunction. These findings offer new insights into how OS disrupts bone formation and may contribute to the development of osteoporosis.

Relationship between neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, platelet-to-lymphocyte ratio and osteoporosis in postmenopausal type 2 diabetic patients: A retrospective study

Neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR) are newly discovered inflammatory markers in recent years. To explore the relationship between NLR, MLR, PLR, and bone mineral density (BMD), as well as osteoporosis (OP), in postmenopausal patients with type 2 diabetes mellitus (T2DM). 320 postmenopausal patients with T2DM who were admitted to the Department of Endocrinology and Metabolic Diseases of our hospital from January 2022 to January 2024 for treatment were included in this retrospective study. The patients were divided into 3 groups according to the BMD: normal bone mass group (n = 109), osteopenia group (n = 99), and OP group (n = 112). Clinical data and blood laboratory parameters were collected from the patients. The NLR, MLR, and PLR were calculated. Statistically significant differences were found in the comparison of NLR, MLR, and PLR among the 3 groups of patients (P < .001). The OP group had higher NLR, MLR, and PLR than the normal bone mass group and the osteopenia group. NLR, MLR, and PLR were negatively correlated with BMD at the lumbar spine (L1-L4), left femoral neck, and left hip, respectively. Analysis revealed that elevated levels of NLR and PLR were independent risk factors for OP in postmenopausal patients. The results of the receiver operating characteristic curve analysis indicated that the area under the curve (AUC) for NLR was higher than that of PLR. Combined use of NLR and PLR resulting in an improved AUC of 0.904. Neutrophils produce mediators such as interferon-gamma (IFN-γ), interleukin-6 (IL-6), interleukin-1 (IL-1), and receptor activator of nuclear factor kappa-B ligand (RANKL), which increase the number and activity of osteoclasts. Peripheral blood monocytes play a vital role in osteoclastogenesis as osteoclast precursors. The BMD of postmenopausal T2DM patients is negatively correlated with NLR, MLR, and PLR. NLR and PLR can both serve as predictive indicators for the occurrence of OP in postmenopausal T2DM patients.

3D-printed bone regeneration scaffolds modulate bone metabolic homeostasis through vascularization for osteoporotic bone defects

The treatment of osteoporotic bone defects poses a challenge due to the degradation of the skeletal vascular system and the disruption of local bone metabolism within the osteoporotic microenvironment. However, it is feasible to modulate the disrupted local bone metabolism imbalance through enhanced vascularization, a theory termed "vascularization-bone metabolic balance". This study developed a 3D-printed polycaprolactone (PCL) scaffold modified with EPLQLKM and SVVYGLR peptides (PCL-SE). The EPLQLKM peptide attracts bone marrow-derived mesenchymal stem cells (BMSCs), while the SVVYGLR peptide enhances endothelial progenitor cells (EPCs) vascular differentiation, thus regulating bone metabolism and fostering bone regeneration through the paracrine effects of EPCs. Further mechanistic research demonstrated that PCL-SE promoted the vascularization of EPCs, activating the Notch signaling pathway in BMSCs, leading to the upregulation of osteogenesis-related genes and the downregulation of osteoclast-related genes, thereby restoring bone metabolic balance. Furthermore, PCL-SE facilitated the differentiation of EPCs into "H"-type vessels and the recruitment of BMSCs to synergistically enhance osteogenesis, resulting in the regeneration of normal microvessels and bone tissues in cases of femoral condylar bone defects in osteoporotic SD rats. This study suggests that PCL-SE supports in-situ vascularization, remodels bone metabolic translational balance, and offers a promising therapeutic regimen for osteoporotic bone defects.

Harnessing hydrogen sulfide in injectable hydrogels that guide the immune response and osteoclastogenesis balance for osteoporosis treatment

Elevated levels of oxidative stress, inflammation, and a dysregulated osteoclastogenesis balance frequently characterize the microenvironment of osteoporosis, which impedes the processes of healing and repair. Existing treatment approaches are limited in scope and rely primarily on factors and drugs. An injectable hydrogel designed for the ROS-responsive release of H2S gas is presented in this study. The first network of the hydrogel comprises sodium alginate (SA-SATO) chelated with S-aroylthiooxime (SATO) and an H2S-generating group, while the second network is composed of photocrosslinkable PEGDA. Through the integration of Cys-releasing microspheres that are reactive with ROS, a composite hydrogel was developed that exhibited advantageous mechanical characteristics and biosafety. The composite hydrogel effectively promoted osteogenic differentiation of mesenchymal stem cells, modulated macrophage polarization, decreased inflammatory responses, and halted cell apoptosis, as evidenced by in vitro experiments. Additionally, it released H2S gas and mitigated excess ROS in cells. The efficacy of the composite hydrogel in promoting bone defect repair and regeneration in an osteoporotic model was further validated by in vivo findings. In summary, the composite hydrogel exhibits potential as a viable approach to address osteoporotic bone defects by harmonizing osteogenesis and osteoclast activity, modulating the microenvironment of bone injuries, and reducing inflammation. Consequently, it presents a viable strategy for the efficient repair of bone defects.

Electroacupuncture on GB acupoints improves osteoporosis via the estradiol-PI3K-Akt signaling pathway

Recent studies have reported that electroacupuncture (EA) can treat osteoporosis, but most of which were based on the "kidney governing bones" theory. However, the ancient Chinese medical textbook Huangdi Neijing pointed out that "Gallbladder Meridian of Foot Shaoyang" correlates with bone diseases, including osteoporosis, although the therapeutic regimens were lost after the Tang Dynasty. Here, we explored whether EA at GB points improves osteoporosis and its underlying mechanism. We constructed ovariectomized mice and treated them with EA at GB30 (Huantiao), GB34 (Yanglingquan), and GB39 (Xuanzhong) acupoints. EA treatment significantly improved bone parameters in osteoporotic mice, as evidenced by micro-computed tomography and histological assessment. Additionally, EA treatment elevated the serum levels of estradiol and SOD that were downregulated in osteoporotic mice. Transcriptome and qPCR results verified that EA treatment upregulated the expression of genes associated with bone formation. Moreover, transcriptome analysis revealed differential enrichment of the PI3K-Akt pathway. Furthermore, Western blot analysis demonstrated that estradiol partially counteracted a reduction in p-AKT expression induced by hydrogen peroxide. These findings indicate that EA treatment increases serum estradiol levels in mice, thus inhibiting osteoporosis induced by oxidative stress. This effect is achieved by activating the PI3K-Akt signaling pathway.

Primary Osteoporosis Induced by Androgen and Estrogen Deficiency: The Molecular and Cellular Perspective on Pathophysiological Mechanisms and Treatments

Primary osteoporosis is closely linked to hormone deficiency, which disrupts the balance of bone remodeling. It affects postmenopausal women but also significantly impacts older men. Estrogen can promote the production of osteoprotegerin, a decoy receptor for RANKL, thereby preventing RANKL from activating osteoclasts. Furthermore, estrogen promotes osteoblast survival and function via activation of the Wnt signaling pathway. Likewise, androgens play a critical role in bone metabolism, primarily through their conversion to estrogen in men. Estrogen deficiency accelerates bone resorption through a rise in pro-inflammatory cytokines (IL-1, IL-6, TNF-α) and RANKL, which promote osteoclastogenesis. In the classic genomic pathway, estrogen binds to estrogen receptors in the cytoplasm, forming a complex that migrates to the nucleus and binds to estrogen response elements on DNA, regulating gene transcription. Androgens can be defined as high-affinity ligands for the androgen receptor; their combination can serve as a ligand-inducible transcription factor. Hormone replacement therapy has shown promise but comes with associated risks and side effects. In contrast, the non-genomic pathway involves rapid signaling cascades initiated at the cell membrane, influencing cellular functions without directly altering gene expression. Therefore, the ligand-independent actions and rapid signaling pathways of estrogen and androgen receptors can be harnessed to develop new drugs that provide bone protection without the side effects of traditional hormone therapies. To manage primary osteoporosis, other pharmacological treatments (bisphosphonates, teriparatide, RANKL inhibitors, sclerostin inhibitors, SERMs, and calcitonin salmon) can ameliorate osteoporosis and improve BMD via actions on different pathways. Non-pharmacological treatments include nutritional support and exercise, as well as the dietary intake of antioxidants and natural products. The current study reviews the processes of bone remodeling, hormone actions, hormone receptor status, and therapeutic targets of primary osteoporosis. However, many detailed cellular and molecular mechanisms underlying primary osteoporosis seem complicated and unexplored and warrant further investigation.

Effect of Facial Acupuncture Stimulation: MRI-Based Masseter Muscle Volume Analysis and Questionnaire Evaluation

Background

Cosmetic acupuncture may reduce wrinkles, swelling, sagging, and facial asymmetry and may lift facial contours.

Objectives

To investigate the impact of cosmetic acupuncture on masseter muscle volume and its implications for facial aesthetics.

Methods

The authors included 10 apparently healthy adult females (average age, 50.3 ± 6.45 years) and performed acupuncture once a week for 8 weeks. MRI was conducted before acupuncture stimulation and 3 days after the treatment. The collected image data were analyzed using ZioCube software (ZioSoft Co., Ltd, Tokyo). Before and after the intervention, 2 evaluators measured the masseter muscle volume 3 times each and calculated the average value.

Results

The average total volume of the left and right masseter muscles decreased from 40.73 ± 8.2 to 37.81 ± 8.57 cm3 after cosmetic acupuncture, a significant reduction of 2.92 ± 2.48 cm3 (7.37%, P < .05). All 10 subjective evaluation items showed significant decreases, particularly in facial sagging, contour, and asymmetry, confirming aesthetic improvements and psychological satisfaction among participants. Cosmetic acupuncture reduced masseter muscle volume, leading to noticeable aesthetic benefits.

Conclusions

Acupuncture stimulation at acupoints around the masseter muscle can reduce the muscle volume because of muscle relaxation. The improvement in subjective evaluation and changes and decreases in masseter muscle shape enable the attainment of facial contour aesthetics, contributing to the evidence in support of cosmetic acupuncture.

Level of Evidence 4 Therapeutic

Changes in Muscle Mass and Bone Density and Their Relationship After Total Knee Arthroplasty

Purpose: To investigate the effects of total knee arthroplasty (TKA) on muscle mass and bone density in end-stage knee osteoarthritis (OA). Methods: This prospective study was conducted on 111 patients with Kellgren-Lawrence grade 4 knee OA who underwent TKA after failing to respond to conservative treatment for more than 3 months at a single institution from June 2022 to May 2023. Appendicular lean mass index (ALMI) and bone mineral density (BMD) were measured using dual-energy X-ray absorptiometry before and every 6 months after surgery. The average follow-up period was 15.5 ± 2.31 months (range, 11.6-24 months). Results: During the follow-up period after TKA, the ALMI increased relatively continuously and consistently. The BMD of the L-spine and proximal femur did not change significantly until 12 months after TKA surgery but began to increase steeply after 12 months and slowed down after 18 months. The increase in muscle mass showed a significant positive correlation with the increase in BMD. Conclusions: Muscle mass gradually increased after TKA for end-stage knee OA, whereas bone density also increased but not until 12 months after surgery. The significant positive correlation between the increase in muscle mass and bone density suggests that the increase in muscle mass after TKA may be one of the causes of the increase in bone density.

Estimating lumbar bone mineral density from conventional MRI and radiographs with deep learning in spine patients

PURPOSE

This study aimed to develop machine learning methods to estimate bone mineral density and detect osteopenia/osteoporosis from conventional lumbar MRI (T1-weighted and T2-weighted images) and planar radiography in combination with clinical data and imaging parameters of the acquisition protocol.

METHODS

A database of 429 patients subjected to lumbar MRI, radiographs and dual-energy x-ray absorptiometry within 6 months was created from an institutional database. Several machine learning models were trained and tested (373 patients for training, 86 for testing) with the following objectives: (1) direct estimation of the vertebral bone mineral density; (2) classification of T-score lower than - 1 or (3) lower than - 2.5. The models took as inputs either the images or radiomics features derived from them, alone or in combination with metadata (age, sex, body size, vertebral level, parameters of the imaging protocol).

RESULTS

The best-performing models achieved mean absolute errors of 0.15-0.16 g/cm2 for the direct estimation of bone mineral density, and areas under the receiver operating characteristic curve of 0.82 (MRIs) - 0.80 (radiographs) for the classification of T-scores lower than - 1, and 0.80 (MRIs) - 0.65 (radiographs) for T-scores lower than - 2.5.

CONCLUSIONS

The models showed good discriminative performances in detecting cases of low bone mineral density, and more limited capabilities for the direct estimation of its value. Being based on routine imaging and readily available data, such models are promising tools to retrospectively analyse existing datasets as well as for the opportunistic investigation of bone disorders.

Antioxidant 1,2,3,4,6-Penta-O-galloyl-β-D-glucose Alleviating Apoptosis and Promoting Bone Formation Is Associated with Estrogen Receptors

1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG) is the main phenolic active ingredient in Paeoniae Radix Alba, which is commonly used for the treatment of osteoporosis (OP). PGG is a potent natural antioxidant, and its effects on OP remain unknown. This study aimed to investigate the effects of PGG on promoting bone formation and explore its estrogen receptor (ER)-related mechanisms. A hydrogen peroxide-induced osteoblast apoptosis model was established in MC3T3-E1 cells. The effects of PGG were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry, alkaline phosphatase (ALP) staining, RT-qPCR, and Western blot methods. Furthermore, a prednisolone-induced zebrafish OP model was employed to study the effects in vivo. ER inhibitors and molecular docking methods were used further to investigate the interactions between PGG and ERs. The results showed that PGG significantly enhanced cell viability and decreased cell apoptosis by restoring mitochondrial function, attenuating reactive oxygen species levels, decreasing the mitochondrial membrane potential, and enhancing ATP production. PGG enhanced ALP expression and activity and elevated osteogenic differentiation. PGG also promoted bone formation in the zebrafish model, and these effects were reversed by ICI182780. These results provide evidence that the effects of PGG in alleviating apoptosis and promoting bone formation may depend on ERs. As such, PGG is considered a valuable candidate for treating OP.

Divergent associations of inflammatory markers with bone turnover markers in elderly patients with osteoporotic fractures

The association between inflammatory markers (IMs) and bone turnover markers (BTMs) in osteoporotic fracture patients has not been comprehensively studied. Therefore, this study examined the correlation between the platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), or Monocyte-to-lymphocyte ratio (MLR) and BTMs in osteoporosis (OP) fracture patients. This retrospective cross-sectional study analyzed 740 OP fracture patients admitted to the hospital from January 2017 to July 2022. MLR, NLR, and PLR were calculated based on each patient's complete blood count. The relationship between IMs and BTMs was assessed using three models by adjusting variables. Furthermore, the potential curve relationship between IMs and BTMs was also determined via the threshold effect analysis and curve fittings. In addition, stratified analysis was performed on each adjusted variable to confirm the stability of the results. After adjusting the variables, the results showed that NLR was negatively correlated with procollagen type 1 N-terminal propeptide (P1NP) (β = -1.1788, 95% CI: -1.7230 to -0.6345, P-value < 0.0001) and β-C-terminal telopeptide of type I collagen (β-CTX) (β = -0.0104, 95% CI: -0.0145 to -0.0062, P-value < 0.0001), Furthermore, MLR was negatively correlated with P1NP (β = -17.4523, 95% CI: -27.7335 to -7.1710, P-value = 0.0009) and β-CTX (β = -0.1327, 95% CI: -0.2211 to -0.0443, P-value = 0.0034). However, PLR indicated a positive correlation with P1NP (β = 0.0326, 95% CI: 0.0007 to 0.0645, P-value = 0.0458) and β-CTX (β = 0.0003, 95% CI: 0.0001 to 0.0006, P-value = 0.0204). The threshold effect analysis and curve fittings revealed the presence of a turning point between NLR, MLR, and P1NP, β-CTX. In addition, the stratified analysis validated the result's stability. In conclusion, this study indicates a negative correlation between NLR and MLR with P1NP, while PLR shows a positive correlation with P1NP. Additionally, NLR and MLR exhibit a negative correlation with β-CTX, whereas PLR demonstrates a positive correlation with β-CTX. Further research is required to assess the intricate mechanisms linking IM with bone metabolism.

Association between dietary vitamin E and osteoporosis in older adults in the United States

Background

Increased oxidative stress due to aging can lead to increased bone loss. The most abundant form of vitamin E, namely α-tocopherol, has high antioxidant properties and biological activity; however, its effect on osteoporosis has not been well studied in humans. We aimed to investigate the association between dietary vitamin E (α-tocopherol) and osteoporosis among older adults in the United States.

Methods

This cross-sectional study analyzed data on older adults in the United States aged ≥50 years from the 2007-2010, 2013-2014 and 2017-2020 pre-pandemic cycles of the National Health and Nutrition Examination Survey. Sample-weighted multivariate regression models were used, with adjustments for relevant confounders.

Results

This study comprised 5,800 individuals with available data on dietary intake and bone mineral density of hip and spine. The mean participant age was 61.4 (standard deviation, 8.7) years, and approximately 9.9% had osteoporosis. High vitamin E intake was significantly associated with a reduced risk of osteoporosis (odds ratio, 0.96, 95% confidence interval, 0.93-0.98). In addition, there was evidence of interaction between dietary vitamin E and prior fracture on preventing osteoporosis.

Conclusions

Our study indicated a linear association between dietary vitamin E levels and osteoporosis in an older population in the United States. Further research is required to explore the potential effects of different forms of vitamin E on osteoporosis.

Cinobufagin Suppresses Lipid Peroxidation and Inflammation in Osteoporotic Mice by Promoting the Delivery of miR-3102-5p by Macrophage-Derived Exosomes

BACKGROUND

Cinobufagin, the primary active compound in toad venom, is commonly used for anti-tumor, anti-inflammatory, and analgesic purposes. However, its specific bone-protective effects remain uncertain. This research aims to ascertain the bone-protective properties of cinobufagin and investigate underlying mechanisms.

METHODS

Mice were ovariectomized to establish an osteoporosis model, followed by intraperitoneal injections of cinobufagin and cinobufagin-treated RAW.264.7-derived exosomes for therapy. MicroCT, HE staining, and TRAP staining were employed to evaluate bone mass and therapeutic outcomes, while mRNA sequencing and immunoblotting were utilized to assess markers of bone metabolism, inflammation, and lipid peroxidation. Osteoblast and osteoclast precursor cells were differentiated to observe the impact of cinobufagin-treated exosomes derived from RAW264.7 cells on bone metabolism. Exosomes characteristics were studied using transmission electron microscopy and particle size analysis, and miRNA binding targets in exosomes were determined by luciferase reporting.

RESULTS

In ovariectomized mice, cinobufagin and cinobufagin-treated exosomes from RAW264.7 cells increased trabecular bone density and mass in the femur, while also decreasing inflammation and lipid peroxidation. The effect was reversed by an exosomes inhibitor. In vitro experiments revealed that cinobufagin-treated exosomes from RAW264.7 cells enhanced osteogenic and suppressed osteoclast differentiation, possibly linked to Upregulated miR-3102-5p in RAW-derived exosomes. MiR-3102-5p targets the 3'UTR region of alox15, thereby suppressing its expression and reducing the lipid peroxidation process in osteoblasts.

CONCLUSION

Overall, this study clarified cinobufagin's bone-protective effects and revealed that cinobufagin can enhance the delivery of miR-3102-5p targeting alox15 through macrophage-derived exosomes, demonstrating anti-lipid peroxidation and anti-inflammatory effects.

The Role of Mitochondrial Permeability Transition in Bone Metabolism, Bone Healing, and Bone Diseases

Bone is a dynamic organ with an active metabolism and high sensitivity to mitochondrial dysfunction. The mitochondrial permeability transition pore (mPTP) is a low-selectivity channel situated in the inner mitochondrial membrane (IMM), permitting the exchange of molecules of up to 1.5 kDa in and out of the IMM. Recent studies have highlighted the critical role of the mPTP in bone tissue, but there is currently a lack of reviews concerning this topic. This review discusses the structure and function of the mPTP and its impact on bone-related cells and bone-related pathological states. The mPTP activity is reduced during the osteogenic differentiation of mesenchymal stem cells (MSCs), while its desensitisation may underlie the mechanism of enhanced resistance to apoptosis in neoplastic osteoblastic cells. mPTP over-opening triggers mitochondrial swelling, regulated cell death, and inflammatory response. In particular, mPTP over-opening is involved in dexamethasone-induced osteoblast dysfunction and bisphosphonate-induced osteoclast apoptosis. In vivo, the mPTP plays a significant role in maintaining bone homeostasis, with many bone disorders linked to its excessive opening. Genetic deletion or pharmacological inhibition of the over-opening of mPTP has shown potential in enhancing bone injury recovery and alleviating bone diseases. Here, we review the findings on the relationship of the mPTP and bone at both the cellular and disease levels, highlighting novel avenues for pharmacological approaches targeting mitochondrial function to promote bone healing and manage bone-related disorders.

Tissue expression and promoter activity analysis of the porcine TNFSF11 gene

Tumour necrosis factor (TNF) superfamily member 11 (TNFSF11), also known as RANKL, plays a crucial role in regulating several physiological and pathological activities. Additionally, it is a vital factor in bone physiology, and the sex hormone progesterone regulates the expansion of stem cells and the proliferation of mammary epithelial cells. It is essential for animal growth and reproductive physiological processes. This study aimed to evaluate the tissue-specific expression characteristics and promoter activity of the TNFSF11 gene in pigs. As a result, the study examined the presence of TNFSF11 expression in the tissues of Xiangsu pigs at 0.6 and 12 months of age. Moreover, the core promoter region of TNFSF11 was also identified by utilizing a combination of bioinformatic prediction and dual-luciferase activity tests. Finally, the effect of transcription factors on the transcriptional activity of the core promoter region was determined using site-directed mutagenesis. TNFSF11 was uniformly expressed in all tissues; however, its expression in muscles was comparatively low. The core promoter region of TNFSF11 was located in the -555 to -1 region. The prediction of the transcription start site of TNFSF11 gene-2000 ∼ + 500bp showed that there was a CpG site in 17 ∼ + 487bp. Analysis of mutations in the transcription factor binding sites revealed that mutations in the Stat5b, Myog, Trl, and EN1 binding sites had significant effects on the transcriptional activity of the TNFSF11 gene, particularly following the EN1 binding site mutation (P < 0.001). This study provides insights into both the tissue-specific expression patterns of TNFSF11 in the tissues of Xiangsu pigs and the potential regulatory effects of transcription factors on its promoter activity. These results may be helpful for future research aimed at clarifying the expression and role of the porcine TNFSF11 gene.

The effectiveness of intravenous zoledronic acid in elderly patients with osteoporosis after rotator cuff repair: a retrospective study

The aim of this study was to investigate the effect of zoledronic acid (ZA) on postoperative healing and functional rehabilitation in osteoporotic patients with rotator cuff (RC) injury. 96 Patients were divided into three groups according to bone mineral density and ZA use (Group A: normal BMD; Group B: osteoporosis and intravenous ZA use; Group C: osteoporosis, without ZA use). Radiologic, functional and Serological outcomes were evaluated 6 months after surgery. The functional scores in all groups exhibited significant improvement 6 months after surgery. Inter-group comparison showed that Constant Shoulder joint function Score (CSS) of group A not significantly differing from that of group B, the other indicators were significantly better than those of group B and C. There were no significant differences in shoulder forward flexion, abductive Range of Motion between group B and C. Other indicators of group B were significantly improved compared to group C. The retear rate in group C (30.3%, 10/33) was higher than group A (6.1%, 2/33) and group B (13.3%, 4/30). In conclusion, the application of ZA can significantly reduce the rate of RC retear in elderly patients with osteoporosis after surgery, which is significant for postoperative shoulder joint functional rehabilitation.

Multi-functional PEEK implants enhance osseointegration in OVX rat by remodeling the bone immune microenvironment

Osseointegration is significantly impeded in osteoporotic conditions due to the elevated levels of reactive oxygen species (ROS) and inflammation at the site of injury. To enhance bone regeneration in osteoporotic conditions, a modified polyether ether ketone (PEEK) implants was prepared, denoted as PEEK-PDA-Sr. The implants consisted of mussel adhesion layer with the conjugation of strontium (Sr) ions, which can constantly release Sr ions for up to 3 weeks. PEEK-PDA-Sr demonstrated excellent biocompatibility and effectively regulated intracellular ROS levels and macrophage differentiation. In addition, the PEEK-PDA-Sr facilitated the osteogenesis of bone marrow stromal cells (BMSCs). In the ovariectomized (OVX) rat model of osteoporosis, the PEEK-PDA-Sr exhibited raised osseointegration in the femoral bone defects. The PEEK-PDA-Sr can be used as an immunoregulator with enhanced osseointegration and osteogenesis both in vivo and in vitro, which provides an available approach to treat osteoporotic bone defects.

Effectiveness of anthocyanin-rich foods on bone remodeling biomarkers of middle-aged and older adults at risk of osteoporosis: a systematic review, meta-analysis, and meta-regression

CONTEXT

Current osteoporosis pharmacological treatment has undesirable side effects. There is increasing focus on naturally derived food substances that contain phytonutrients with antioxidant effects in promoting health and regulating immune response.

OBJECTIVE

This review aims to systematically evaluate the effectiveness of anthocyanin-rich foods on bone remodeling biomarkers in middle-aged and older adults (≥40 y old) at risk of osteoporosis.

DATA SOURCES

Randomized controlled trials were searched on 8 bibliographic databases of PubMed, Embase, Scopus, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Food Science and Technology Abstracts, Cochrane Library, and ProQuest.

DATA EXTRACTION AND ANALYSIS

Thirteen studies were included in the meta-analysis. Receptor activator of nuclear factor kappa-B ligand (RANKL) is exhibited from osteoblastic cells that gathered osteoclasts to bone sites for bone resorption, accelerating bone loss. Anthocyanin-rich food consumption showed statistically nonsignificant effects, with no substantial heterogeneity on bone remodeling biomarkers. However, there was a significant increase in lumbar spine L1-L4 bone mineral density. Mild-to-small effects were seen to largely favor the consumption of anthocyanin-rich foods. Berries (d = -0.44) have a larger effect size of RANKL than plums (d = 0.18), with statistically significant subgroup differences. Random-effects meta-regression found body mass index, total attrition rate, total energy, and dietary carbohydrate and fat intake were significant covariates for the effect size of RANKL. All outcomes had low certainty of evidence.

CONCLUSION

Anthocyanin-rich foods may improve bone health in middle-aged and older adults at risk of osteoporosis. This review contributes to the growing interest in nutrient-rich foods as a low-cost and modifiable alternative to promote human health and reduce disease burden. Future high-quality studies with larger sample sizes and longer treatment durations are required to fully understand the effect of anthocyanin-rich foods on bone health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022367136.

Association Between Combined Polymetallic Exposure and Osteoporosis

Combined polymetallic exposure may be an influential factor in osteoporosis. This study aimed to explore the association between polymetallic combined exposure and osteoporosis. A total of 2115 participants were included. Plasma concentrations of 22 metals were determined by inductively coupled plasma mass spectrometry. Osteoporosis was defined as a T ≤  - 2.5. The least absolute shrinkage and selection operator (LASSO) regression, binary logistics regression, and Bayesian kernel machine regression (BKMR) model were used to explore the association between plasma metals and osteoporosis. LASSO regression showed that 10 metals were associated with osteoporosis in the total population (magnesium, calcium, manganese, nickel, cobalt, arsenic, selenium, rubidium, cadmium, aluminum) and women (magnesium, calcium, molybdenum, nickel, cobalt, arsenic, selenium, rubidium, cadmium, aluminum), and four metals associated with men (magnesium, cobalt, aluminum, iron). Logistics regression showed that in total population, magnesium (ORQ3 = 0.653, 95% CI = 0.446-0.954) was negatively correlated with osteoporosis, while aluminum (ORQ2 = 1.569, 95% CI = 1.095-2.248, ORQ4 = 1.616, 95% CI = 1.109-2.354) and cadmium (ORQ4 = 1.989, 95% CI = 1.379-2.870) were positively correlated; in women, magnesium (ORQ3 = 0.579, 95% CI = 0.379-0.883) was negatively correlated with osteoporosis, while aluminum (ORQ2 = 1.563, 95% CI = 1.051-2.326, ORQ4 = 1.543, 95% CI = 1.024-2.326) and cadmium (ORQ3 = 1.482, 95% CI = 1.003-2.191, ORQ4 = 1.740, 95% CI = 1.167-2.596) were positively correlated. BKMR model showed that combined polymetallic exposure had an overall positive effect on osteoporosis, magnesium was negatively associated with osteoporosis, and cadmium, selenium, and aluminum were positively associated with osteoporosis. Metal mixtures in plasma were associated with osteoporosis risk. Magnesium may reduce the risk of osteoporosis, while cadmium, selenium, and aluminum may increase the risk of osteoporosis. Future studies needed to explore correlations and mechanisms.

Hydroxysafflor yellow A ameliorates alcohol-induced liver injury through PI3K/Akt and STAT3/NF-κB signaling pathways

BACKGROUND

Alcohol-associated liver disease (ALD) is a prevalent liver ailment. It has escalated into a significant public health issue, imposing substantial burdens on medical, economic, and social domains. Currently, oxidative stress, inflammation, and apoptosis are recognized as crucial culprits in improving ALD. Consequently, mitigating these issues has emerged as a promising avenue for enhancing ALD. Hydroxysafflor yellow A (HSYA) is the main ingredient in safflower, showing excellent antioxidative stress, anti-inflammatory, and anti-apoptosis traits. However, there are limited investigations into the mechanisms by which HSYA ameliorates ALD PURPOSE: We investigated whether HSYA, a significant constituent of Asteraceae safflower, exerts antioxidant stress and attenuates inflammation and anti-apoptotic effects through PI3K/Akt and STAT3/NF-κB pathways, thereby ameliorating ALD METHODS: We established two experimental models: an ethanol-induced liver damage mouse model in vivo and a HepG2 cell alcohol injury model in vitro RESULTS: The results demonstrated that HSYA effectively ameliorated liver tissue damage, reduced levels of ALT, AST, LDL-C, TG, TC, and MDA, enhanced HDL-C levels, SOD and GSH activities, reduced ROS accumulation in cells, and activated the Nrf2 pathway, a transcription factor involved in antioxidant defense. By regulating the PI3K/Akt and STAT3/NF-κB pathways, HSYA exhibits notable antioxidative stress, anti-inflammatory, and anti-apoptotic effects, effectively impeding ALD's advancement. To further confirm the regulatory effect of HSYA on PI3K/Akt and downstream signaling pathways, the PI3K activator 740 Y-P was used and was found to reverse the downregulation of PI3K by HSYA CONCLUSION: This study supports the effectiveness of HSYA in reducing ALD by regulating the PI3K/Akt and STAT3/NF-κB pathways, indicating its potential medicinal value.

Advances in mechanobiological pharmacokinetic-pharmacodynamic models of osteoporosis treatment - Pathways to optimise and exploit existing therapies

Osteoporosis (OP) is a chronic progressive bone disease which is characterised by reduction of bone matrix volume and changes in the bone matrix properties which can ultimately lead to bone fracture. The two major forms of OP are related to aging and/or menopause. With the worldwide increase of the elderly population, particularly age-related OP poses a serious health issue which puts large pressure on health care systems. A major challenge for development of new drug treatments for OP and comparison of drug efficacy with existing treatments is due to current regulatory requirements which demand testing of drugs based on bone mineral density (BMD) in phase 2 trials and fracture risk in phase 3 trials. This requires large clinical trials to be conducted and to be run for long time periods, which is very costly. This, together with the fact that there are already many drugs available for treatment of OP, makes the development of new drugs inhibitive. Furthermore, an increased trend of the use of different sequential drug therapies has been observed in OP management, such as sequential anabolic-anticatabolic drug treatment or switching from one anticatabolic drug to another. Running clinical trials for concurrent and sequential therapies is neither feasible nor practical due to large number of combinatorial possibilities. In silico mechanobiological pharmacokinetic-pharmacodynamic (PK-PD) models of OP treatments allow predictions beyond BMD, i.e. bone microdamage and degree of mineralisation can also be monitored. This will help to inform clinical drug usage and development by identifying the most promising scenarios to be tested clinically (confirmatory trials rather than exploratory only trials), optimise trial design and identify subgroups of the population that show benefit-risk profiles (both good and bad) that are different from the average patient. In this review, we provide examples of the predictive capabilities of mechanobiological PK-PD models. These include simulation results of PMO treatment with denosumab, implications of denosumab drug holidays and coupling of bone remodelling models with calcium and phosphate systems models that allows to investigate the effects of co-morbidities such as hyperparathyroidism and chronic kidney disease together with calcium and vitamin D status on drug efficacy.

Bone Fragility in Diabetes and its Management: A Narrative Review

Bone fragility is a serious yet under-recognised complication of diabetes mellitus (DM) that is associated with significant morbidity and mortality. Multiple complex pathophysiological mechanisms mediating bone fragility amongst DM patients have been proposed and identified. Fracture risk in both type 1 diabetes (T1D) and type 2 diabetes (T2D) continues to be understated and underestimated by conventional risk assessment tools, posing an additional challenge to the identification of at-risk patients who may benefit from earlier intervention or preventive strategies. Over the years, an increasing body of evidence has demonstrated the efficacy of osteo-pharmacological agents in managing skeletal fragility in DM. This review seeks to elaborate on the risk of bone fragility in DM, the underlying pathogenesis and skeletal alterations, the approach to fracture risk assessment in DM, management strategies and therapeutic options.

Emerging role of liver-bone axis in osteoporosis

Background

Increasing attention to liver-bone crosstalk has spurred interest in targeted interventions for various forms of osteoporosis. Liver injury induced by different liver diseases can cause an imbalance in bone metabolism, indicating a novel regulatory paradigm between the liver and bone. However, the role of the liver-bone axis in both primary and secondary osteoporosis remains inadequately elucidated. Therefore, exploring the exact regulatory mechanisms of the liver-bone axis may offer innovative clinical approaches for treating diseases associated with the liver and bone.

Methods

Here, we summarize the latest research on the liver-bone axis by searching the PubMed and Web of Science databases and discuss the possible mechanism of the liver-bone axis in different types of osteoporosis. The literature directly reporting the regulatory role of the liver-bone axis in different types of osteoporosis from the PubMed and Web of Science databases has been included in the discussion of this review (including but not limited to the definition of the liver-bone axis, clinical studies, and basic research). In addition, articles discussing changes in bone metabolism caused by different etiologies of liver injury have also been included in the discussion of this review (including but not limited to clinical studies and basic research).

Results

Several endocrine factors (IGF-1, FGF21, hepcidin, vitamin D, osteocalcin, OPN, LCAT, Fetuin-A, PGs, BMP2/9, IL-1/6/17, and TNF-α) and key genes (SIRT2, ABCB4, ALDH2, TFR2, SPTBN1, ZNF687 and SREBP2) might be involved in the regulation of the liver-bone axis. In addition to the classic metabolic pathways involved in inflammation and oxidative stress, iron metabolism, cholesterol metabolism, lipid metabolism and immunometabolism mediated by the liver-bone axis require more research to elucidate the regulatory mechanisms involved in osteoporosis.

Conclusion

During primary and secondary osteoporosis, the liver-bone axis is responsible for liver and bone homeostasis via several hepatokines and osteokines as well as biochemical signaling. Combining multiomics technology and data mining technology could further advance our understanding of the liver-bone axis, providing new clinical strategies for managing liver and bone-related diseases.The translational potential of this article is as follows: Abnormal metabolism in the liver could seriously affect the metabolic imbalance of bone. This review summarizes the indispensable role of several endocrine factors and biochemical signaling pathways involved in the liver-bone axis and emphasizes the important role of liver metabolic homeostasis in the pathogenesis of osteoporosis, which provides novel potential directions for the prevention, diagnosis, and treatment of liver and bone-related diseases.

Is bone mineral density in middle-aged and elderly individuals associated with their dietary patterns? A study based on NHANES

Introduction

Bone mineral density (BMD) is a crucial index for predicting fracture risk and diagnosing osteoporosis. With the global rise in osteoporosis prevalence, understanding the relationship between dietary patterns and BMD is vital for public health. This study aimed to explore the association between various dietary patterns and BMD among adults using data from the National Health and Nutrition Examination Survey (NHANES).

Methods

Data were analyzed from 8,416 NHANES participants aged 40 years and older across three non-consecutive survey cycles from 2013 to 2020. Dietary patterns were identified using a combination of factor analysis and cluster analysis. BMD measurements were then assessed, and associations with the identified dietary patterns were analyzed, with adjustments made for demographic variables.

Results

The analysis identified three distinct dietary patterns: "Low protein-High Dietary fiber-Vitamin A-Magnesium (LP-HDF-Vit A-Mg)", "High macronutrient-Choline-Selenium (HM-Cho-Se)", and "Low macronutrient-Vitamin D-Calcium (LM-Vit D-Ca)", and then we found that women, older adults, and certain ethnic groups were at higher risk for low BMD. Participants adhering to the "HM-Cho-Se" and "LP-HDF-Vit A-Mg" dietary patterns exhibited significantly higher BMD compared to those following the "LM-Vit D-Ca" pattern. After adjusting for demographic variables, the "HM-Cho-Se" pattern remained positively associated with BMD, while the "LM-Vit D-Ca" pattern showed no significant association with BMD or the risk of low BMD.

Discussion

The findings suggest that adherence to the "HM-Cho-Se" dietary pattern may reduce the risk of low BMD, indicating potential synergies between these nutrients for bone health. However, the study has limitations, including the cross-sectional design and potential subjectivity in factor analysis. Future research should focus on longitudinal studies involving diverse age groups to better understand the causal relationship between dietary patterns and BMD. Despite these limitations, the study highlights the importance of dietary factors in maintaining bone health and suggests potential dietary interventions to reduce the risk of low BMD and osteoporosis.

The potential therapeutic role of curcumin in osteoporosis treatment: based on multiple signaling pathways

Osteoporosis is a common chronic metabolic bone disease caused by disturbances in normal bone metabolism and an imbalance between osteoblasts and osteoclasts. Osteoporosis is characterized by a decrease in bone mass and bone density, leading to increased bone fragility. Osteoporosis is usually treated with medications and surgical methods, but these methods often produce certain side effects. Therefore, the use of traditional herbal ingredients for the treatment of osteoporosis has become a focus of attention and a hot topic in recent years. Curcumin, widely distributed among herbs such as turmeric, tulip, and curcuma longa, contains phenolic, terpenoid, and flavonoid components. Modern pharmacological studies have confirmed that curcumin has a variety of functions including antioxidant and anti-inflammatory properties. In addition, curcumin positively regulates the differentiation and promotes the proliferation of osteoblasts, which play a crucial role in bone formation. Multiple studies have shown that curcumin is effective in the treatment of osteoporosis as it interacts with a variety of signaling pathway targets, thereby interfering with the formation of osteoblasts and osteoclasts and regulating the development of osteoporosis. This review summarized the key signaling pathways and their mechanisms of action of curcumin in the prevention and treatment of osteoporosis and analyzed their characteristics and their relationship with osteoporosis and curcumin. This not only proves the medicinal value of curcumin as a traditional herbal ingredient but also further elucidates the molecular mechanism of curcumin's anti-osteoporosis effect, providing new perspectives for the prevention and treatment of osteoporosis through multiple pathways.

Sirt1: An Increasingly Interesting Molecule with a Potential Role in Bone Metabolism and Osteoporosis

Osteoporosis (OP) is a common metabolic bone disease characterized by low bone mass, decreased bone mineral density, and degradation of bone tissue microarchitecture. However, our understanding of the mechanisms of bone remodeling and factors affecting bone mass remains incomplete. Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent deacetylase that regulates a variety of cellular metabolisms, including inflammation, tumorigenesis, and bone metabolism. Recent studies have emphasized the important role of SIRT1 in bone homeostasis. This article reviews the role of SIRT1 in bone metabolism and OP and also discusses therapeutic strategies and future research directions for targeting SIRT1.

Osteoporosis and Alzheimer´s disease (or Alzheimer´s disease and Osteoporosis)

Alzheimer's disease (AD) and osteoporosis are two diseases that mainly affect elderly people, with increases in the occurrence of cases due to a longer life expectancy. Several epidemiological studies have shown a reciprocal association between both diseases, finding an increase in incidence of osteoporosis in patients with AD, and a higher burden of AD in osteoporotic patients. This epidemiological relationship has motivated the search for molecules, genes, signaling pathways and mechanisms that are related to both pathologies. The mechanisms found in these studies can serve to improve treatments and establish better patient care protocols.

Thioredoxin Interacting Protein Expressed in Osteoblasts Mediates the Anti-Proliferative Effects of High Glucose and Modulates the Expression of Osteocalcin

BACKGROUND

Hyperglycemia is associated with impaired bone health in patients with diabetes mellitus. Although a direct detrimental effect of hyperglycemia on the bone has been previously reported, the specific molecular mediator(s) responsible for the inhibitory effect of high glucose levels on the bone remains unclear. We hypothesized that thioredoxin-interacting protein (Txnip), an essential mediator of oxidative stress, is such a mediator.

METHODS

We cultured MG-63 cells (immortalized human osteoblasts) with normal or high glucose concentrations and transfected them with scrambled or Txnip-specific small interfering RNA (siRNA).

RESULTS

High glucose levels increased Txnip expression and reduced MG-63 cell proliferation. The high-glucose level mediated reduction in cell proliferation was prevented in Txnip siRNA-transfected cells. In addition, we demonstrated that silencing Txnip mRNA expression in osteoblasts reduced the expression of the osteocalcin gene. Our results suggest that high glucose levels or silencing of Txnip mRNA expression may induce apoptosis in osteoblasts.

CONCLUSIONS

Our findings indicate that Txnip is an intracellular mediator of the anti-proliferative effects of extracellular high glucose levels on osteoblasts.

An update on the role of ferroptosis in the pathogenesis of osteoporosis

Ferroptosis is a novel form of programmed cell death, distinguished from apoptosis, autophagy, and programmed necrosis and has received much attention since it was defined in 2012. Ferroptotic cells physiologically exhibit iron metabolism dysregulation, oxidative stress, and lipid peroxidation. Morphologically, they show plasma membrane disruption, cytoplasmic swelling, and mitochondrial condensation. Osteoporosis is taken more and more seriously as the proportion of the aging population continues to increase globally. Interestingly, ferroptosis has been demonstrated to be involved in the development and progression of osteoporosis in many extant studies. The review summarizes iron metabolism, lipid peroxidation, and the different regulatory signals in ferroptosis. Changes in signaling mechanisms within osteoblasts, osteoclasts, and osteocytes after ferroptosis occur are explained here. Studies showed ferroptosis play an important role in different osteoporosis models (diabetes osteoporosis, postmenopausal osteoporosis, glucocorticoid-induced osteoporosis). Inhibitors and EC (Exos) targeting ferroptosis could ameliorate bone loss in osteoporotic mice by protecting cells against lipid peroxidation. Shortly, we hope that more effective and appropriate clinical therapy means will be utilized in the treatment of osteoporosis.

Crosstalk between bone and brain in Alzheimer's disease: Mechanisms, applications, and perspectives

Alzheimer's disease (AD) is a neurodegenerative disease that involves multiple systems in the body. Numerous recent studies have revealed bidirectional crosstalk between the brain and bone, but the interaction between bone and brain in AD remains unclear. In this review, we summarize human studies of the association between bone and brain and provide an overview of their interactions and the underlying mechanisms in AD. We review the effects of AD on bone from the aspects of AD pathogenic proteins, AD risk genes, neurohormones, neuropeptides, neurotransmitters, brain-derived extracellular vesicles (EVs), and the autonomic nervous system. Correspondingly, we elucidate the underlying mechanisms of the involvement of bone in the pathogenesis of AD, including bone-derived hormones, bone marrow-derived cells, bone-derived EVs, and inflammation. On the basis of the crosstalk between bone and the brain, we propose potential strategies for the management of AD with the hope of offering novel perspectives on its prevention and treatment. HIGHLIGHTS: The pathogenesis of AD, along with its consequent changes in the brain, may involve disturbing bone homeostasis. Degenerative bone disorders may influence the progression of AD through a series of pathophysiological mechanisms. Therefore, relevant bone intervention strategies may be beneficial for the comprehensive management of AD.

Global Trends in Research of Programmed Cell Death in Osteoporosis: A Bibliometric and Visualized Analysis (2000-2023)

Osteoporosis (OP) is a systemic metabolic bone disease that is characterized by decreased bone mineral density and microstructural damage to bone tissue. Recent studies have demonstrated significant advances in the research of programmed cell death (PCD) in OP. However, there is no bibliometric analysis in this research field. This study searched the Web of Science Core Collection (WoSCC) database for literature related to OP and PCD from 2000 to 2023. This study used VOSviewers 1.6.20, the "bibliometrix" R package, and CiteSpace (6.2.R3) for bibliometric and visualization analysis. A total of 2905 articles from 80 countries were included, with China and the United States leading the way. The number of publications related to PCD in OP is increasing year by year. The main research institutions are Shanghai Jiao Tong University, Chinese Medical University, Southern Medical University, Zhejiang University, and Soochow University. Bone is the most popular journal in the field of PCD in OP, and the Journal of Bone and Mineral Research is the most co-cited journal. These publications come from 14,801 authors, with Liu Zong-Ping, Yang Lei, Manolagas Stavros C, Zhang Wei, and Zhao Hong-Yan having published the most papers. Ronald S. Weinstein was co-cited most often. Oxidative stress and autophagy are the current research hot spots for PCD in OP. This bibliometric study provides the first comprehensive summary of trends and developments in PCD research in OP. This information identifies the most recent research frontiers and hot directions, which will provide a definitive reference for scholars studying PCD in OP.