Unveiling causal pathways in autoimmune diseases: a multi-omics approach

Autoimmune diseases (ADs), such as Graves' disease (GD), Hashimoto's thyroiditis (HT), psoriasis, systemic lupus erythematosus (SLE), and type 1 diabetes (T1D), involve complex immune and inflammatory responses. This study employed Mendelian randomization (MR) analysis using genome-wide association study (GWAS) data to examine the causal relationships among 91 circulating inflammatory proteins, 41 cytokines, 211 gut microbiota, and 731 immune cell traits in relation to ADs. Additionally, we integrated mediation and bioinformatics analyses, including protein-protein interaction (PPI) networks, Gene Ontology (GO) enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Subnetwork discovery and key protein identification were performed using the Molecular Complex Detection (MCODE) plugin, alongside colocalization analysis and drug target exploration to identify potential mechanisms. MR analysis identified significant causal relationships between various circulating inflammatory proteins, cytokines, gut microbiota species, immune cells, and ADs, with certain relationships retaining significance after false discovery rate (FDR) correction. Mediation analysis demonstrated that inflammatory proteins mediate pathogenic pathways linking immune cells to psoriasis and gut microbiota to Hashimoto's thyroiditis. PPI and bioinformatics analyses highlighted 22 key proteins involved in ADs, while subnetwork analysis identified 15 central proteins. Fms-related tyrosine kinase 3 ligand (FLT3LG) exhibited strong colocalization evidence. Molecular docking confirmed several proteins as viable drug targets. This comprehensive multi-omics study advances our understanding of ADs, identifies novel therapeutic targets, and offers valuable insights for developing new treatment strategies.

The research progress into cellular mechanosensitive ion channels mediating cancer pain

Cellular mechanotransduction refers to the process through which cells perceive mechanical stimuli and subsequently translate them into biochemical signals. Key mechanosensitive ion channels encompass PIEZO, TREK-1, and TRESK. These mechanosensitive ion channels are crucial in regulating specific pathophysiological conditions, including fibrosis, tumor progression, and cellular proliferation and differentiation. Recent research indicates that PIEZO, TREK-1, and TRESK are significant contributors to various types of cancer pain by sensing mechanical stimuli, which subsequently activate internal signaling pathways. Here concentrates on advancements in research concerning PIEZO, TREK-1, and TRESK in cancer pain research, aiming to lay the groundwork for creating new therapeutic drugs that address mechanosensitive ion channels for treating cancer pain.

Faecalibacterium prausnitzii prevents age-related heart failure by suppressing ferroptosis in cardiomyocytes through butyrate-mediated LCN2 regulation

Aging is a primary driver of the escalating prevalence of heart failure (HF). Age-associated gut microbiota dysbiosis has been implicated in various age-related diseases, yet its role in age-related HF remains largely unexplored. In this study, we sought to explore the potential link between age-related gut microbiota alterations and HF in the elderly. We analyzed a publicly available single-cell sequencing dataset, which revealed markedly increased ferroptosis activity in cardiac myocytes of elderly individuals compared to their younger counterparts. Notably, treatment with the ferroptosis inhibitor, ferrostatin-1, mitigated cardiac ferroptosis and prevented cardiac dysfunction in aging rats. Furthermore, fecal microbiota transplantation from elderly HF patients significantly increased cardiac ferroptosis activity and induced cardiac dysfunction in healthy recipient rats. Integrated 16S rRNA sequencing and PCR quantification revealed a marked depletion of Faecalibacterium prausnitzii (F. prausnitzii) in elderly individuals, with a more pronounced decline in elderly patients with HF. Oral administration of F. prausnitzii or its metabolite butyrate effectively attenuated age-related HF through inhibiting ferroptosis. Additionally, gene-editing techniques were employed to generate F. prausnitzii BCoAT mutant deficient in butyrate production. Intriguingly, the protective effect was lost in the butyrate-deficient F. prausnitzii strain. Mechanistically, butyrate reduced intracellular iron accumulation and suppressed ferroptosis by downregulating LCN2 expression in senescent cardiomyocytes. Our findings highlight the critical role of aged microbiota-induced ferroptosis in HF and propose F. prausnitzii or butyrate may serve as potential targets for the prevention and treatment of age-related HF.

Bioinformatic identification of important roles of COL1A1 and TNFRSF12A in cartilage injury and osteoporosis

OBJECTIVE

The aim of this study was to identify the key regulatory mechanisms of cartilage injury and osteoporosis through bioinformatics methods, and to provide a new theoretical basis and molecular targets for the diagnosis and treatment of the disease.

METHODS

Microarray data for cartilage injury (GSE129147) and osteoporosis (GSE230665) were first downloaded from the GEO database. Differential expression analysis was applied to identify genes that were significantly up-or down-regulated in the cartilage injury and osteoporosis samples. These genes were subjected to GO enrichment analysis and KEGG pathway analysis. In addition, we employed SVA and RRA methods to merge the two sets of data, eliminating batch effects and enhancing the statistical power of the analysis. Through WGCNA, we identified gene modules that were closely associated with disease phenotypes and then screened for key genes that intersected with differentially expressed genes. The diagnostic value of these genes as potential biomarkers was evaluated by ROC analysis. Moreover, we performed an immune infiltration analysis to explore the correlation between these core genes and immune cell infiltration.

RESULTS

We performed GO enrichment analysis and KEGG pathway analysis of genes significantly up-or down-regulated in cartilage injury and osteoporosis samples. Important biological processes, cellular components and molecular functions, and key metabolic or signaling pathways associated with osteoporosis and cartilage injury were identified. Through WGCNA, we identified gene modules that were closely associated with the disease phenotype, from which we then screened for key genes that intersected with differentially expressed genes. Ultimately, we focused on two identified core genes, COL1A1 and TNFRSF12A, and assessed the diagnostic value of these genes as potential biomarkers by ROC analysis. Meanwhile, GSVA provided an in-depth view of the role of these genes in disease-specific biological pathways. Immune infiltration analysis further revealed the possible key role of COL1A1 and TNFRSF12A in regulating immune cell infiltration in osteoporosis and cartilage injury.

CONCLUSION

COL1A1 and TNFRSF12A as key regulatory molecules in osteoporosis and cartilage injury.

Bioactive Zn ingredients endow Ti-Zn composites with exceptional mechanical and osteogenic properties as biomedical implants

Titanium-based (Ti-) alloys are promising materials as bioimplants with superior mechanical properties and excellent biocompatibility. However, their bioinertia and high elastic moduli are not comparable to natural bone tissue; thus, novel Ti alloys with good biomechanical adaptation and high bioactivity are desired. Zinc (Zn) is recognized for ideal biodegradability and its biological effects can be considered to endow pure Ti with rewarding bio functions. Herein, this study has employed a designed spark plasma sintering (SPS) procedure to effectively diffuse varying amounts of Zn into pure Ti as bioactive ingredients and generate novel TiZn composites as bone defect implants. The as-sintered TiZn samples feature a gradient core-shell structure, achieving a match of high strength and low elastic moduli to satisfy the load-bearing requirements while avoiding the stress-shielding effect. A moderate degradation of the Zn component allows TiZn materials to maintain stable mechanical support and exhibit satisfactory cytocompatibility. Ti20Zn, Ti30Zn, and Ti90Zn are confirmed to exert antibacterial and osteogenic abilities by in vitro experiments. Further analyses of in vivo implantation in the rat femur show they exhibit qualified biosafety and are superior to pure Ti in treating bone defects through bio-friendly Zn ions release. This study achieves a reasonable combination of the mechanical properties of pure Ti and the biological functions of pure Zn, providing a better choice for bone injury and fracture treatment.

Lamb1-mediated Wnt/β-catenin signaling pathway drives endothelial angiogenesis for fracture healing

OBJECTIVES

Fractures, usually caused by trauma or osteoporosis, are the most common traumatic injuries to large organs in humans. Osteogenesis and angiogenesis are two crucial parts of fracture healing that work together to promote the repair and regeneration of damaged bone. Endothelial cell migration is critical for angiogenesis. Therefore, it is well worth exploring whether endothelial cells (ECs) can enhance fracture healing.

METHODS

The public datasets were analyzed by scRNA-seq, and the ECs were subjected to subset analysis and pseudotime analysis. Next, ECs_Lamb1+ cells underwent GO and KEGG pathway enrichment analyses, and were subjected to GSVA. Finally, the mechanism was verified and evaluated via qRT-PCR, cellular immunofluorescence staining, and transwell assay.

RESULTS

After cell annotations, 9 cell types were obtained, and it was found that the proportions of ECs were significantly reduced. EC subset analysis showed that the ratio of ECs_Lamb1+ cells was significantly up-regulated in the Fracture group; pseudotime analysis showed that ECs_Lamb1- cells were gradually reduced over time, whereas ECs_Lamb1+ cells were gradually expanding along the trajectories to reach a maximum at the end of the trajectory; pathway enrichment analyses revealed that ECs_Lamb1+ cells were mainly associated with several signaling pathways regulating cell proliferation, differentiation, repair, angiogenesis, and inflammatory responses, such as PI3K-Akt signaling pathway, Wnt/β-catenin, and MAPK. The results of basic assays demonstrated that successful knockdown of Lamb1 expression via siRNA-LAMB1 was detrimental to HUVEC proliferation, migration, and tube formation, and could suppress the expression of wnt3a, GSK-3β, β-catenin, and VEGFA; whereas, HY-141873 in combination with siRNA-LAMB1 partially reversed the down-regulated wnt3a, GSK-3β, β-catenin, and VEGFA expression, and HUVEC proliferation, migration, and tube formation were partially improved.

CONCLUSION

Lamb1 promotes fracture repair and healing by up-regulating VEGFA expression via the activation of Wnt signaling pathway to catalyze EC growth and migration and induce endothelial angiopoiesis.

Global trends in proximal femoral trabecular research: A bibliometric and visualized analysis

Introduction

Hip disease is a global public health issue, associated with high morbidity, mortality, and healthcare costs. Although research on proximal femoral trabeculae has been conducted for over a century, no bibliometric analysis has been carried out. The purpose of this study is to evaluate the existing research landscape, identify emerging trends, and offer insights for future studies.

Method

The scientific output related to the trabeculae within the human proximal femur from 2004 to 2023 was sourced from the Web of Science Core Collection. Moreover, both the annual publications and cumulative totals over this period were summarized in Excel. The VOS viewer was utilized to analyze co-authorship and co-citation relationship between authors, institutions, countries, references and journals. CiteSpace was used to cluster the keywords and research frontiers in this field.

Results

A total of 365 publications were extracted, with the USA emerging as the primary contributor to this field, accounting for 133 publications with 5807 total citations, averaging 43.7 citations per publication. The Journal of Bone and Mineral Research has been identified as the most co-cited journal with a total of 1742 citations. The journals can be categorized into 5 distinct clusters, including medical imaging, orthopedic clinical research, research on endocrine and metabolic related diseases, human evolution and anatomy related research, biomechanics and modeling. The keyword with the highest co-occurrence frequency is "bone mineral density". The keywords were stratified into six clusters, including DXA, bone remodeling, diagnosis, titanium alloy bionic cannulated screws, individual trabecula segmentation, and QCT. More recently, the focus has expanded to three-dimensional modeling, falls, microarchitecture, and avascular necrosis.

Conclusions

Evaluation of proximal femoral strength can be improved by combining structural parameters with bone mineral density by DXA or QCT. Three-dimensional analysis, microarchitecture, and bionic implants are emerging as significant areas of focus and trends for future research.

Association between serum Copper-Zinc-Selenium mixture and multiple health outcomes

Background

Metallic biomaterials have transformed modern medicine, with copper (Cu), zinc (Zn), and selenium (Se) emerging as critical components in medical applications. The study of the single and synergistic effects of serum metal concentrations on human health can provide valuable insights for future clinical transformation of biodegradable alloys.

Methods

We evaluated 2381 NHANES 2011-2016 participants to study individual and combined effects of these metals on health outcomes. Multivariable logistic regression, restricted cubic splines, and piecewise linear regression were used to examine linear, nonlinear, and threshold relationships. Overall metal mixture effects were assessed using weighted quantile sum (WQS) and Bayesian kernel-machine regression (BKMR).

Results

Elevated serum Cu levels were significantly associated with an increased risk of osteoarthritis. When Serum Cu ≥ 99.48 μg/dL, each 1-unit increase in Ln Cu raised diabetes risk 4.55-fold. For Se ≥ 122.74 μg/L, each 1-unit increase in Ln Se led to a 29.96-fold rise in diabetes prevalence, for Se < 157.56 μg/L it increased heart attack risk 165.19-fold. Furthermore, mixtures of Cu, Se, and Zn were positively associated with diabetes, hypertension, and heart attack risks; each unit increase in the mixture corresponded to a 23 % rise in diabetes and a 15 % rise in hypertension prevalence.

Conclusions

Serum Cu levels ≥99.48 μg/dL are significantly linked to diabetes risk, while serum Se levels ≥122.74 μg/L are associated with diabetes risk and levels <157.56 μg/L with elevated heart attack risk. Serum metal mixtures containing Cu, Se and Zn were significantly and positively associated with risk of diabetes, hypertension and heart attack.

A highly positively charged Ru(II) complex with photo-labile ligands for selective and efficient photo-inactivation of intracellular Staphylococcus aureus

Due to the protection afforded by host cells, intracellular Staphylococcus aureus (S. aureus), particularly methicillin-resistant S. aureus (MRSA), poses a significantly greater challenge to eliminate compared to the extracellular counterparts. It is highly desirable to develop novel antibacterial agents which are capable of selectively and efficiently eradicating intracellular bacteria, including drug-resistant strains, while being less prone to induce bacterial resistance. In this work, two Ru(II) complexes (Ru1 and Ru2) with photo-labile ligands were designed and synthesized. Both Ru1 and Ru2 could covalently bind to DNA after photo-induced ligand dissociation. Compared to Ru1, the incorporation of a triphenylamine group adorned with two positively charged cationic pyridine units significantly boosts the DNA binding constant, bacterial binding/uptake level, and subsequently, the antibacterial activity of Ru2. Ru2 could selectively photo-inactivate intracellular S. aureus and MRSA, being more efficient than vancomycin both in vitro and in vivo. Interestingly, after 20 days' treatment at sublethal concentrations, S. aureus cells exhibited no obvious drug resistance towards Ru2 upon irradiation. Such appealing results may provide new sights for developing novel antibacterial agents against intractable intracellular pathogens and also prevalent drug resistance.

Lenalidomide attenuates cardiac fibrosis and inflammation induced by β-adrenergic receptor activation

β-Adrenergic receptor (β-AR) excessive activation assumes a vital role in various cardiovascular diseases and mediates cardiac fibrosis and cardiac inflammation. Lenalidomide (Len) has shown anti-fibrosis effects in diverse fibrotic diseases. However, it is unclear whether and how Len suppresses cardiac fibrosis and cardiac inflammation triggered by β-AR overactivation. In our research, mice were treated in the presence of or in the absence of the β-AR agonist isoproterenol (ISO) and with or without Len pretreatment. Interestingly, the results showed that Len alleviated β-AR-induced cardiac dysfunction and cardiac fibrosis by PI3K/AKT and ERK signalings in vivo. Consistently, Len also attenuated β-AR-induced cardiac fibroblasts activation by PI3K/AKT and ERK signalings in vitro. Besides, Len suppressed β-AR-induced cardiac inflammation by PI3K/AKT and NF-κB signalings in vivo. Similarly, Len inhibited β-AR-induced macrophages pro-inflammatory cytokines expression by PI3K/AKT and NF-κB signalings in vitro. To further explore the protective mechanism of Len, we used KEGG enrich analysis and found that Len functioned in therapeutic effects by targeting AKT1 in both cardiac fibroblasts and macrophages. In summary, our study demonstrated that Len ameliorated cardiac fibrosis and cardiac inflammation upon β-adrenergic insult. And the mechanism suggested that Len function in cardiac fibrosis and inflammation via targeting AKT1.

Iron dysregulation, ferroptosis, and oxidative stress in diabetic osteoporosis: Mechanisms, bone metabolism disruption, and therapeutic strategies

Diabetic osteoporosis (DOP) is a common complication in diabetes, driven by hyperglycemia-induced metabolic disturbances, chronic inflammation, and oxidative stress. This review describes the critical role of iron metabolism dysregulation in DOP pathogenesis, focusing on ferroptosis, a novel iron-dependent cell death pathway characterized by lipid peroxidation and reactive oxygen species (ROS) overproduction. Diabetic conditions exacerbate iron overload, impairing osteoblast function and enhancing osteoclast activity, while triggering ferroptosis in bone cells. Ferroptosis not only accelerates osteoblast apoptosis but also amplifies osteoclast-mediated bone resorption, synergistically promoting bone loss. Furthermore, chronic inflammation and oxidative stress disrupt the balance between bone formation and resorption, with elevated pro-inflammatory cytokines (e.g., tumor necrosis factor-α, interleukin-6) and ROS exacerbating cellular dysfunction. Therapeutic strategies targeting iron metabolism (e.g., deferoxamine) and ferroptosis inhibition (e.g., nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway activation, antioxidants like melatonin) demonstrate potential to mitigate DOP progression. Future research should prioritize personalized interventions, clinical trials of iron chelators and antioxidants, and mechanistic studies to refine therapeutic approaches. This review provides a comprehensive framework for understanding DOP pathogenesis and highlights innovative strategies to improve bone health in diabetic patients.

Advancements in bone organoids: perspectives on construction methodologies and application strategies

BACKGROUND

In clinical practice and research, bone defects due to tumor growth, trauma, and different pathological conditions are significant challenges. Although bone possesses an intrinsic capacity for regeneration, extensive bone abnormalities necessitate applying advanced methods for regenerating bone. Bone organoids have made methodological breakthroughs in this field, and the use of bone organoids to repair bone defects has gained wide acceptance in the scientific community, supported by a large body of experimental evidence.

AIM OF REVIEW

This review synthesizes existing literature and ground-breaking studies to provide an in-depth examination of the bone organoid model, exploring the fundamental architecture and development of bone and emphasizing recent advancements in bone organoid fabrication, such as the application of 3D bioprinting technology in bone organoid fabrication. Furthermore, the study suggests potential directions for future research, highlighting the critical role of interdisciplinary collaboration in fully harnessing the potential of this rapidly evolving field. Key scientific concepts of review Bone organoids involve the 3D self-organization of in vitro-cultured bone-associated stem cells, optionally including extracellular matrix components. This process generates tissue closely resembling the original bone tissue's functional, genetic, and structural features. Bone organoids are more promising than traditional methods of bone defect repair. In addition, tissue engineering technologies such as 3D bioprinting have opened up new opportunities for constructing bone organoids. Future research should prioritize the development of composite bone organoids, enhancement of bone organoid stiffness, and improvement of bioactive materials, as well as the exploration and development of novel bioinks to facilitate the application of bone organoids in bone repair and regeneration.

Overcoming biological inertness: multifaceted strategies to optimize PEEK bioactivity for interdisciplinary clinical applications

Polyether ether ketone (PEEK), characterized by a comparable elastic modulus to human bone with high wear resistance, radiolucency, and biocompatibility, demonstrates considerable promise for clinical applications. However, due to the significant limitations in clinical applications caused by the biological inertness of PEEK, it should first be modified to meet clinical needs. Currently, the field of PEEK modifications is rapidly advancing, with a particular emphasis on enhancing its biological properties. Most of the previous reviews have separately discussed strategies like antibacterial, osteogenic, and angiogenic enhancements for PEEK. This review combines cross-domain insights to update and synthesize recent research on PEEK composites, focusing on advanced multi-component sustained release platforms that mimic postoperative biological processes. Such temporal alignment between material functionality and physiological healing phases demonstrates unprecedented potential for expanding PEEK's clinical versatility.

Circulating Essential Trace Element and Mineral Levels in Female Patients with Knee or Concomitant Knee and Hip Osteoarthritis

The objective of the present study was to evaluate serum trace element and mineral levels in female patients with knee osteoarthritis (kOA) and concomitant knee and hip osteoarthritis (khOA). The study enrolled 61 healthy women without OA or any other pathology of joints (OA-free group), 180 subjects with bilateral kOA, and 99 patients with khOA. Age, anthropometric parameters, and the prevalence of concomitant diseases were registered. Serum trace element and mineral levels were assessed using inductively-coupled plasma mass-spectrometry. The obtained data demonstrate that patients with kOA and especially khOA are characterized by higher age, body mass index, and the prevalence of hypertension and certain other comorbidities. Serum analysis demonstrated that Zn and Fe levels in kOA and khOA patients were lower than those in OA-free patients by 7% and 9%, and 14% and 18%, respectively. In turn, circulating Se concentrations in patients with kOA and khOA were 9% and 7% lower compared to OA-free group values. Serum Cu and Mo levels in khOA patients exceeded the respective values in kOA subjects. Factorial analysis demonstrated that OA case status had a significant impact on serum Ca, Cr, Fe, Mn, Se, V, and Zn. At the same time, multiple regression analysis revealed a significant association with OA only for serum Zn, Se, V after adjustment for age, BMI, and the prevalence of concomitant diseases. Therefore, the obtained data indicate that involvement of multiple joints in OA patients is associated with more severe alterations in trace element levels.

Irisin alleviates steroid-induced vascular dysfunction by regulating the αVβ5-c-Abl-Caveolin-1 signaling pathway

Steroid-induced avascular necrosis of the femoral head (SANFH) is a progressive degenerative disease of the hip, primarily due to glucocorticoid (GC)-induced endothelial cell (EC) injury and compromised blood supply. Irisin is an EC-protective mytokine whose receptor is the integrin αVβ5. Caveolin-1 (CAV-1)， a major component of caveolae, causes endothelial dysfunction when phosphorylated. However, the role of irisin and CAV-1 in SANFH remains unclear. In our study, irisin levels decreased but CAV-1 phosphorylation increased in human and mouse SANFH samples. Intraperitoneal irisin injection (250 μg/kg daily) notably reduced GC-induced osteonecrosis, vascular abnormalities, and CAV-1 phosphorylation in SANFH mice. In cultured ECs, GC induced CAV-1 phosphorylation by activating c-Abl via the glucocorticoid receptor, and irisin inhibited GC-induced phosphorylation of c-Abl and CAV-1 via the integrin αVβ5. Inhibition of integrin αVβ5 also abolished the protective effects of irisin on ERK and eNOS signalling, viability, angiogenesis, and migration in ECs. Therefore, our findings indicate that irisin has a protective role against vascular dysfunction in SANFH, possibly mediated by the inhibition of GC-triggered c-Abl-CAV-1 phosphorylation through integrin αVβ5. These findings provide insights into the potential therapeutic applications of irisin in SANFH.

Synthesis of Autotaxin-Inhibiting Lipid Nanoparticles to Regulate Autophagy and Inflammatory Responses in Activated Macrophages

BACKGROUND

Autotaxin (ATX), an ENPP2 enzyme, regulates lipid signaling by converting lysophosphatidylcholine to lysophosphatidic acid (LPA). Dysregulation of the ATX/LPA axis promotes inflammation and disease progression. BMP-22, a lipid ATX inhibitor, effectively reduces LPA production. However, its clinical utility is hampered by limitations in solubility and pharmacokinetics. To overcome these limitations, we developed BMP-22-incorporated lipid nanoparticles (LNP-BMP) to improve utility while maintaining ATX inhibition efficacy.

METHODS

LNP-BMP was synthesized by incorporating DOTAP, DOPE, cholesterol, 18:0 PEG2000-PE, and together with BMP-22. The formulation of LNP-BMP was optimized and characterized by testing different molar ratios of BMP-22. The autophagy recovery and anti-inflammatory effects of LNP-BMP via ATX inhibition were evaluated in both macrophage cell line and mouse-derived primary macrophages.

RESULTS

LNP-BMP was shown to retain its functionality as an ATX inhibitor and maintain the physical characteristics upon BMP-22 integration. Synthesized LNP-BMP exerted superior ability to inhibit ATX activity. When applied to M1-induced macrophages, LNP-BMP exhibited substantial anti-inflammatory effects and successfully restored autophagy activity.

CONCLUSION

The results demonstrate that LNP-BMP effectively inhibits ATX, achieving both anti-inflammatory effects and autophagy restoration, highlighting its potential as a standalone immunotherapeutic agent. Furthermore, the capacity to load therapeutic drugs into this formulation offers promising opportunities for further therapeutic strategies.

Antisenescence therapies for age-related bone loss: Target factors, medicines, biomedical materials

Progress in living conditions and medical technology have extended the human life span such that population aging, and thus the development of multi-system degenerative diseases, has become a major problem in many countries. Bone is a metabolically dynamic tissue and bone aging is closely related to a shift in the balance between bone resorption and bone formation. The resulting loss of bone mass and bone mechanical properties in older adults place them at risk of injury and premature death. Cellular senescence occurs in response to endogenous and exogenous stresses that lead to permanent cell cycle arrest and, thus, to tissue degeneration and dysfunction. Senescence in the bone microenvironment, as occurs during aging, induces a decline in bone formation. Research into the treatment of bone aging has therefore focused on the senescence process. This review begins with a summary of the key events in cellular senescence and bone aging and then examines recent progress in the targeting of cellular senescence, both to treat aging-related bone diseases. Novel therapeutic agents, natural products, and innovative biomedical materials are considered. Our discussion concludes by considering areas of future research.

Robotic functional alignment in knee arthroplasty minimizes impact on ankle alignment: Role of MPTA and LDFA preservation

PURPOSE

Alignment strategies in knee arthroplasty have a profound influence not only on knee biomechanics but also on the biomechanics of adjacent joints, particularly the ankle. Functional alignment (FA) represents a flexible alignment strategy aimed at achieving patient-specific balance. However, predefined boundaries are often applied to ensure mechanical stability, leading to adjustments in the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA) while still respecting the patient's native alignment as much as possible. FA is a patient-specific strategy that seeks to respect the patient's preoperative phenotype or constitutional alignment while achieving a balanced and stable knee. The hypothesis is that FA strategies can protect the ankle from excessive biomechanical stress.

METHODS

A retrospective cohort analysis was conducted on 300 consecutive patients who underwent robotic-assisted knee arthroplasty. Preoperative and 6-month post-operative radiographic evaluations measured key ankle parameters, tibial plafond inclination (TPI), talar inclination (TI) and Talar Tilt (TT). Statistical analyses evaluated the influence of alignment strategies on these parameters, with particular focus on whether MPTA and LDFA crossed the 90° threshold, indicating a shift from varus to valgus or vice versa.

RESULTS

FA demonstrated smaller changes in ankle parameters compared to mechanical alignment (MA). In the FA group, mean changes were 1.8° for KTPA (standard deviation [SD] = 1.1°, p = 0.03), 2.4° for TPI (SD = 1.0°, p = 0.04), 2.1° for TI (SD = 1.3°, p = 0.05) and 1.7° for TT (SD = 0.9°, p = 0.04). The MA group showed greater deviations: 3.9° for KTPA (SD = 1.5°, p = 0.01), 5.2° for TPI (SD = 1.2°, p = 0.02), 4.8° for TI (SD = 1.4°, p = 0.03) and 3.6° for TT (SD = 1.1°, p = 0.04). Alterations in LDFA and MPTA exceeding 2° were significantly associated with worsening ankle alignment. Furthermore, FA, with its goal of maintaining Coronal Plane Alignment of the Knee (CPAK) classification, was associated with minimal modifications to ankle angles, suggesting potential biomechanical benefits as reported in the literature.

CONCLUSIONS

FA was associated with smaller changes in ankle alignment parameters, indicating its ability to better preserve native joint positioning. Future research should focus on longitudinal studies to confirm these benefits and further establish the FA strategy as a standard in knee arthroplasty, particularly its capacity to maintain CPAK classification alignment.

LEVEL OF EVIDENCE

Level III.

Multiscale metal-based nanocomposites for bone and joint disease therapies

Bone and joint diseases are debilitating conditions that can result in significant functional impairment or even permanent disability. Multiscale metal-based nanocomposites, which integrate hierarchical structures ranging from the nanoscale to the macroscale, have emerged as a promising solution to this challenge. These materials combine the unique properties of metal-based nanoparticles (MNPs), such as enzyme-like activities, stimuli responsiveness, and photothermal conversion, with advanced manufacturing techniques, such as 3D printing and biohybrid systems. The integration of MNPs within polymer or ceramic matrices offers a degree of control over the mechanical strength, antimicrobial efficacy, and the manner of drug delivery, whilst concomitantly promoting the processes of osteogenesis and chondrogenesis. This review highlights breakthroughs in stimulus-responsive MNPs (e.g., photo-, magnetically-, or pH-activated systems) for on-demand therapy and their integration with biocomposite hybrids containing cells or extracellular vesicles to mimic the native tissue microenvironment. The applications of these composites are extensive, ranging from bone defects, infections, tumors, to degenerative joint diseases. The review emphasizes the enhanced load-bearing capacity, bioactivity, and tissue integration that can be achieved through hierarchical designs. Notwithstanding the potential of these applications, significant barriers to progress persist, including challenges related to long-term biocompatibility, regulatory hurdles, and scalable manufacturing. Finally, we propose future directions, including machine learning-guided design and patient-specific biomanufacturing to accelerate clinical translation. Multiscale metal-based nanocomposites, which bridge nanoscale innovations with macroscale functionality, are a revolutionary force in the field of biomedical engineering, providing personalized regenerative solutions for bone and joint diseases.

Metal-Organic Frameworks: Unlocking New Frontiers in Cardiovascular Diagnosis and Therapy

Cardiovascular disease (CVD) is one of the most critical diseases which is the predominant cause of death in the world. Early screening and diagnosis of the disease and effective treatment after diagnosis play an important role in the patient's recovery. Metal-organic frameworks (MOFs), a kind of hybrid ordered micro or meso-porous materials, constructed by metal nodes or clusters with organic ligands, due to their special features like high porosity and specific surface area, open metal sites, or ligand tunability, are widely used in various areas including gas storage, catalysis, sensors, biomedicine. Recently, advances in MOFs are bringing new developments and opportunities for the healthcare industry including the theranostic of CVD. In this review, the applications of MOFs are illustrated in the diagnosis and therapy of CVD, including biomarker detection, imaging, drug delivery systems, therapeutic gas delivery platforms, and nanomedicine. Also, the toxicity and biocompatibility of MOFs are discussed. By providing a comprehensive summary of the role played by MOFs in the diagnosis and treatment of CVDs, it is hoped to promote the future applications of MOFs in disease theranostics, especially in CVDs.

The Anatomical Basis of Nonuniform Settlement of the C2 Lateral Mass and Its Association With Atlantoaxial Osteoarthritis

OBJECTIVE

Studies have described the nonuniform settlement of C2 lateral mass (C2LM-NUS) as an asymmetrical change of the bilateral C2 lateral masses. This study aimed to: (1) identify the objective evidence for the C2LM-NUS and clarify its anatomical basis; (2) explore the association between C2LM-NUS and atlantoaxial osteoarthritis (AAOA), and verify the related biomechanics.

METHODS

Seventy-nine dry axis specimens were measured macroscopically. The vertical distance between the superior articular surface and the lower edge of the vertebra was defined as the settlement value of C2 lateral mass (C2LMS). Twelve formalin-embalmed axis specimens were scanned using micro-computed tomography (Micro-CT), and the trabecular microstructure of lateral masses was analyzed. 522 patients who underwent a head and neck or cervical spine CT scan were reviewed. The C2LMS was measured, and the bilateral difference (d-C2LMS) was calculated. The AAOA was recorded. Normal and C2LM-NUS upper cervical spine (C0-C3) finite element models were established. The stress distributions on the alar ligament, transverse ligament, and lateral mass cartilage were analyzed using Abaqus software under varying torque conditions.

RESULTS

Macroscopic analysis revealed that the C2LMS measured at the center point was comparable to the overall C2LMS (18.19 ± 1.83 mm vs. 18.18 ± 1.82 mm, p = 0.942). Twenty-seven dry axis specimens (34.2%) were identified as C2LM-NUS because they showed significant differences in bilateral C2LMS (d-C2LMS: 1.21 ± 0.32 mm). Micro-CT analysis revealed that four formalin-embalmed axis specimens with C2LM-NUS exhibited a substantial difference in trabecular microstructural parameters between the settlement and the normal lateral masses. Clinical observations indicated that C2LM-NUS was an independent risk factor for AAOA (adjusted odds ratio = 2.041, p < 0.001). Finite element analysis revealed that in the C2LM-NUS model, the maximum stress on the settlement side of the alar ligament increased by 47.4%-53.3% compared to the opposite side, and the cartilage stress increased by 15.0%-68.5%. Meanwhile, the maximum stress of the transverse ligament in the C2LM-NUS model was 1.3-1.6 times greater than that of the normal model.

CONCLUSIONS

The macroscopic measurement of the axis specimens provided objective anatomic evidence for C2LM-NUS. Micro-CT showed that C2LM-NUS was associated with asymmetrical alterations of the trabecular microstructure of the lateral masses, suggesting that it is a pathological change rather than a normal phenomenon. The clinical study indicated that C2LM-NUS is an independent risk factor for AAOA. Stress concentration in unilateral alar ligaments and articular cartilage is a biomechanical contributor to AAOA.

Angiogenesis-osteogenesis coupling and immunomodulatory CGRP@nano MOF-loaded CMCS/GelMA hydrogel for bone regeneration

The management of bone defects poses a significant challenge for clinicians, necessitating effective strategies to regulate immune inflammation, angiogenesis, and osteogenic differentiation for successful bone regeneration. In this study, we developed a novel hydrogel composed of carboxymethyl chitosan (CMCS) and gelatin methacryloyl (GelMA) designed for the sustained release of the bioactive component calcitonin gene-related peptide (CGRP) and zeolitic imidazolate framework-8 (ZIF-8). CGRP was initially encapsulated within ZIF-8 and subsequently integrated into the CMCS/GelMA hydrogel matrix. In vitro evaluations revealed that the hydrogel exhibited exceptional biocompatibility and antimicrobial properties, effectively promoting osteogenesis and angiogenesis while modulating M2 macrophage polarization. Furthermore, in vivo assessments indicated that the CGRP@MOF/CG hydrogel significantly regulated the local immune microenvironment and accelerated the healing of cranial defects in rat models. This study provides valuable references for the design and fabrication of multifunctional materials for enhancing bone regeneration.

Cu2+/Zn2+ "Antimicrobial Chamber" with Self-Enhanced Photothermal Activity Supports Infected Wound Healing

Wound healing of drug-resistant bacterial infection is a major challenge in clinical practice, and existing treatments suffer from the drawbacks of high dosage, low efficiency, and insufficient biosafety. Herein, we coated ultrasmall copper sulfide nanoparticles (CuS NPs) into zeolitic imidazolate framework-8 (ZIF-8) and modified them with polydopamine (PDA) to obtain CuS@ZIF-8@PDA NPs for bacterial infection wound treatment. Due to the presence of CuS and the degradability of ZIF-8, CuS@ZIF-8@PDA NPs can continuously release Cu2+ and Zn2+ in a slightly acidic environment under near-infrared (NIR) irradiation. Furthermore, the introduction of PDA endows it with an excellent photothermal property. The synergistic effect of dual ions/photothermal enables it to effectively eradicate Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Moreover, in vivo experimental results confirm that released Cu2+ and Zn2+ can promote epithelial regeneration, thereby accelerating wound healing. In the bacterially infected mouse model, CuS@ZIF-8@PDA NPs exhibit excellent synergistic antimicrobial and wound healing effects, while having no toxic side effects on major organs. The study of the dual-ion/photothermal synergistic antibacterial strategy based on CuS@ZIF-8@PDA NPs provides a new insight into bacterial infection wound repair.

METTL9 mediated N1-Histidine methylation of SLC39A7 confers ferroptosis resistance and inhibits adipogenic differentiation in mesenchymal stem cells

Osteoporosis is a prevalent systemic metabolic disease, and an imbalance in the adipogenic and osteogenic differentiation of mesenchymal stem cells (MSCs) plays a crucial role in its pathogenesis. Thus, elucidating the mechanisms that regulate MSC lineage allocation is urgently needed. METTL9 was recently characterized as a novel N1-histidine methyltransferase that performs a wide range of functions. however, the role of METTL9 in the imbalance of MSC differentiation in osteoporosis remains unclear. In this study, we found that METTL9 expression was downregulated in osteoporosis, and further adipogenic functional experiments revealed that METTL9 negatively regulated the adipogenic differentiation of MSCs both in vitro and in vivo. Mechanistically, METTL9 mediated methylation of SLC39A7 at the His45 and His49 residues suppressed ferroptosis through the endoplasmic reticulum (ER) stress regulatory protein kinase R-like endoplasmic reticulum kinase (PERK)/ATF4 signaling pathway and the downstream protein SLC7A11. Moreover, SLC7A11 transported cystine for intracellular glutathione synthesis, eliminating intracellular reactive oxygen species (ROS) and inhibiting MSC adipogenic differentiation. Additionally, METTL9 overexpression significantly alleviated bone loss in ovariectomy (OVX) model mice. In summary, our results suggest that the METTL9/SLC39A7 axis may be a promising diagnostic and therapeutic target for osteoporosis.

Observation of the Effects of Infrapatellar Fat Pad Excision on the Inflammatory Progression of Knee Osteoarthritis in Mice

Background

Knee osteoarthritis (KOA) is a degenerative joint disease characterized by cartilage degradation, synovial inflammation, and joint pain. The infrapatellar fat pad (IFP) has been suggested to play a role in modulating the inflammatory processes in KOA. Excision of the IFP is considered a potential therapeutic approach to reduce inflammation and slow disease progression.

Methods

A mouse model of KOA was used to evaluate the impact of IFP excision on inflammation. Mice were divided into five groups: sham (control), unexcised IFP, quarter excision, partial excision, and complete excision of the IFP. Knee joints were collected at early, middle, and late stages of KOA. Gait analysis, micro-computed tomography (micro-CT), HE staining, Safranin O-Fast Green staining, and immunohistochemistry (IHC) were performed to assess joint stability, bone changes, and inflammatory markers (MMP-3, IL-6, TNF-α, COL-2). qRT-PCR was conducted for cartilage tissue analysis.

Results

Partial IFP excision significantly improved joint stability, particularly in the middle and late stages of KOA. Micro-CT analysis showed increased bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) in excised groups, with the most significant effects in the partial and complete excision groups. IHC and qRT-PCR indicated reduced MMP-3, IL-6, and TNF-α levels in excised groups, particularly in the partial and complete excision groups, suggesting reduced inflammation. COL-2 expression was higher in excised groups, particularly in late-stage KOA, indicating cartilage protection. The partial excision group exhibited the most balanced reduction in inflammation and improved cartilage integrity across all disease stages.

Conclusion

IFP excision, especially partial excision, significantly modulates the inflammatory response in KOA. Partial excision showed the most effective and balanced impact on joint stability, bone integrity, and cartilage protection, offering potential as a therapeutic approach for KOA.

Cerium-Organic Framework and Resveratrol Composite Hydrogel Scaffold with Dual Antioxidant Activity for Enhanced Bone Regeneration

The repair of large bone defects remains a significant challenge in the field of orthopedics, as traditional bone substitutes face issues such as limited supply and structural incompatibility. Therefore, the development of novel biomaterials to promote bone repair is of great significance. This study proposes a composite material based on a gelatin/alginate dual-network hydrogel scaffold (Gel/AlgMA), which regulates oxidative stress in the local microenvironment of bone defects by loading cerium metal-organic frameworks (Ce-UiO-66) and resveratrol (Res). The cerium ions in Ce-UiO-66 exhibit excellent antioxidant properties in their multivalent states, capable of scavenging excess reactive oxygen species (ROS), improving mitochondrial function, and enhancing stability through a polydopamine (PDA) coating. The Gel/Alg@Ce-Res/PDA composite scaffold was prepared via photopolymerization and its in vitro biocompatibility, antioxidant properties, and osteogenic potential were evaluated. The results indicated that the composite scaffold effectively scavenged ROS, alleviated oxidative stress, and promoted the proliferation and differentiation of osteoblasts. Moreover, in vivo experiments further confirmed the favorable effects of the Gel/Alg@Ce-Res/PDA scaffold in bone defect repair. This study provides an innovative biomaterial design for bone defect treatment, with promising clinical application prospects.

Designing Lignin-Based Nanophotocomposites as Reactive Oxygen Species Generators for Inactivating Candida Strains

A combination of sustainable resources and precision biotherapeutics is a game changer for affordable healthcare. A natural biopolymer, lignin, present in agri-biomass, can serve as a nanodrug carrier for targeted delivery. Photodynamic therapy (PDT) is a noninvasive tool to accomplish targeted delivery. Photosensitizers, which are frequently used macrocycles in PDT, lack sufficient hydrophilicity for biological applications. In this regard, lignin-derived nanocarriers provide a sustainable solution, imparting bioavailability to the photosensitizers. In this study, a series of metalloporphyrins were designed and converted into lignin-based nanophotocomposites to augment their photostability and biological efficacy. Such nanophotocomposites played a significant role in eradicating candida infection via PDT by generating reactive oxygen species upon light irradiation. Computational studies (time-dependent density functional theory) established good photosensitizing properties of the metalloporphyrins. These nanophotocomposites demonstrated a pH-triggered release of photosensitizer drugs. The lignin-based nanophotocomposites could be used as low-cost, light-assisted treatment probes for curing candida infections.

Anti-Infection Efficacy, Osteogenesis Potential, and Biocompatibility of 3D Printed PLGA/Nano-Hydroxyapatite Porous Scaffolds Grafted with Vancomycin/DOPA/rhBMP-2 in Infected Rabbit Bone Defects

Background

Given the limitations of traditional therapies, the treatment of infected bone defects (IBD) remains a great challenge. It is urgent to find a novel method that can simultaneously eradicate infection and promote new bone formation. With the increasing application of personalized scaffolds in orthopedics, novel biomaterials with both antibacterial and osteoinductive properties have provided a viable option for IBD treatment. Through the three-dimensional (3D) printing technology, we fabricated a poly(lactic-co-glycolic acid)(PLGA)/nano-hydroxyapatite (n-HA) composite scaffold grafted with the antibiotic vancomycin and loaded with the osteoinductive agent recombinant human bone morphogenic protein-2 (rhBMP-2) via polydopamine (DOPA) chemistry, whose therapeutic effects on IBD were determined.

Methods

After examining the hydrophilicity, surface chemical composition, mechanical properties, and drug release of the PLGA/n-HA, PLGA/n-HA/VAN, and PLGA/n-HA/VAN+DOPA/rhBMP-2 composite scaffolds, pre-osteoblast MC3T3-E1 cells were seeded onto the scaffold surface to assess the biocompatibility and osteoconductive properties of the scaffolds in vitro. For in vivo experiments, the composite scaffolds contaminated with Staphylococcus aureus were implanted into the defect sites of rabbit radius. After 12 weeks, micro-CT analysis, H&E and Masson staining, immunohistochemistry, and viable bacteria counting were conducted to compare the effects of three composite scaffolds on new bone formation and bone infection.

Results

The surface modification with DOPA/rhBMP-2 increased the hydrophilicity of PLGA/n-HA scaffolds. Vancomycin and BMP-2 were continuously and regularly eluted from the PLGA/n-HA/VAN+DOPA/rhBMP-2 scaffolds. The PLGA/n-HA/VAN+DOPA/rhBMP-2 scaffolds promoted MC3T3-E1 cell survival and proliferation and enhanced ALP activity and calcium deposition compared with the PLGA/n-HA and PLGA/n-HA/VAN scaffolds. Additionally, the PLGA/n-HA/VAN+DOPA/rhBMP-2 scaffolds significantly facilitated new bone formation and inhibited bone infection in IBD rabbit models. The rabbits implanted with the PLGA/n-HA/VAN+DOPA/rhBMP-2 scaffolds exhibited normal heart, lung, and kidney histologies and normal serum biochemical indices, suggesting the safety of the scaffolds.

Conclusion

The 3D-printed PLGA/n-HA/VAN+DOPA/rhBMP-2 scaffolds exhibited both antibacterial and osteoinductive activities in IBD.

Osteochondral Alterations in Patients Treated with Total Knee Arthroplasty Due to Rheumatoid Arthritis and Primary Osteoarthritis: Cross-Sectional Study with Focus on Elucidating Effects of Knee Malalignment

Micro-computed tomography assessment of osteochondral microstructural properties of the distal femur and proximal tibia was comprehensively conducted to compare adult patients with knee rheumatoid arthritis (RA) and primary knee osteoarthritis (KOA), with special focus on the effects of knee malalignment. This study encompassed 402 bone samples divided into three groups: the RA group [patients who were subjected to total knee arthroplasty (TKA) due to RA, n = 23, age: 61 ± 10 years], the KOA group [individuals subjected to TKA due to KOA, n = 24, age: 71 ± 9 years] and the control group [sex-matched cadavers without degenerative knee diseases, n = 20, age: 67 ± 11 years]. Our data revealed that the RA, KOA, and control groups differ significantly in osteochondral microstructural properties depending on the knee alignment. Specifically, increasing femoral and tibial cortical porosity, coupled with thinner articular cartilage, were noted in the RA and KOA groups, compared to the controls. Furthermore, larger femoral and tibial cortical pores, lower tibial and femoral subchondral trabecular bone fraction, and thinner tibial articular cartilage were noted in the RA group in comparison to the KOA group, implying that the medial-to-lateral load distribution in the knee joint could be most affected in these patients. Our data illustrated that the thinnest cartilage, a thicker and less porous cortex, along with lower trabecular bone volume, were present in the lateral femoral and tibial condyles of RA individuals with valgus knee alignment. Observed subchondral trabecular microarchitectural alterations could be morphological factors contributing to different effects of surgical treatment and variable implant stability in individuals with RA, warranting further research.

Outer membrane vesicles of Porphyromonas gingivalis impede bone regeneration by inducing ferroptosis via the Hippo-YAP signaling pathway

BACKGROUND

Although increasing evidence confirms that oral microbiota imbalance is a critical factor inhibiting bone regeneration, the specific mechanisms have remained unexplored. This study aims to use periodontitis as a model of oral microbiota imbalance to investigate the specific mechanisms that inhibit bone regeneration in extraction sockets.

METHODS

Cone Beam Computed Tomography (CBCT) data of extraction sockets were collected from patients with and without periodontitis to confirm the influence of the periodontitis microenvironment on bone regeneration in extraction sockets. Furthermore, GW4869-pretreated Porphyromonas gingivalis (Pg) and normal Pg were used to build a periodontitis model, and then the bone regeneration in extraction sockets under these conditions was detected by H&E staining, Masson's staining and micro-CT analysis. In vitro, the effect of Pg-derived OMVs on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) was examined. RNA sequencing, FerroOrange, malondialdehyde assay, transmission electron microscopy, qRT‒PCR, and western blotting analysis were performed.

RESULTS

CBCT analysis showed that periodontitis significantly inhibited new bone formation in the extraction sockets in patients. Micro-CT and Histological analysis revealed that inhibiting OMVs released from Pg alleviated the inhibition of bone regeneration in extraction sockets under Pg imbalance. Moreover, Pg-derived OMVs treatment deteriorated bone regeneration in extraction sockets. In vitro, results showed that Pg-derived OMVs inhibited osteogenic differentiation of BMSCs. Furthermore, the results indicated a significant upregulation of ferroptosis in OMVs-treated BMSCs. Notably, targeting ferroptosis promoted osteogenic differentiation of BMSCs and bone regeneration in extraction sockets, as compared with the OMVs-treated group. Mechanistic studies have shown that Pg-derived OMVs promoted BMSCs ferroptosis via the Hippo- Yes-associated protein (YAP) pathway.

CONCLUSION

This study shows that a Pg microbiota imbalance inhibits bone regeneration by secreting OMVs from Pg to induce ferroptosis in BMSCs. Mechanically, we illustrated that OMVs induce ferroptosis through the Hippo-YAP pathway. These findings might provide a new insight and potential therapeutic target to promote bone regeneration under oral microbiota imbalance.

Theranostics of osteoarthritis: Applications and prospects of precision targeting nanotechnology

Osteoarthritis (OA), a complex degenerative joint disease driven by cartilage degeneration, synovial inflammation, and subchondral bone remodeling, lacks effective disease-modifying therapies. Precision-targeted nanotechnology has emerged as a breakthrough strategy, offering enhanced drug delivery, reduced toxicity, and synergistic diagnostic-therapeutic capabilities. This review summarizes OA pathogenesis, focusing on dysregulated immune networks and self-perpetuating synovial microenvironmental interactions. We discuss advanced nanomedicine approaches, which leverage OA-specific pathological cues for localized treatment. Innovations in cytokine modulation, photothermal therapy, and integrated theranostics (photoacoustic/fluorescence imaging) are highlighted as transformative tools for real-time diagnosis and personalized intervention. Despite progress, challenges such as biocompatibility optimization, clinical translation barriers, OA heterogeneity necessitate further development of multifunctional nanocarriers and rationaldesigns. This work underscores the potential of nanotechnology to advance OA therapeutics, bridging preclinical innovation with clinical applicability in pharmaceutical sciences.

M2 Macrophage-Derived Extracellular Vehicles-Loaded Hyaluronic Acid-Alginate Hydrogel for Treatment of Osteoarthritis

OBJECTIVE

Osteoarthritis (OA), a high-prevalence degenerative cartilage disease, urgently requires novel therapeutic strategies. M2 macrophage-derived exosomes (M2-Exo) demonstrate therapeutic potential for OA, though their regulatory mechanisms in chondrocyte-macrophage (Mφ) interactions remain to be elucidated. To investigate the regulatory effects of M2-Exo on chondrocytes and Mφ in vitro, and to evaluate the therapeutic effect of the M2-Exo-loaded hydrogel system (ALG-M2Exo) on cartilage damage in a rat OA model.

METHODS

In the cell experiment, M2-Exo were extracted and characterized using ultracentrifugation. Different concentrations of M2-Exo were co-cultured with inflammatory chondrocytes or M1Mφ to evaluate their direct anti-inflammatory effects and the ability to promote M1Mφ repolarization to the M2 phenotype, using methods such as EdU, TUNEL, qRT-PCR, and Western blot. Then, the repolarized RM2Mφ were co-cultured with inflammatory chondrocytes to verify their anti-inflammatory efficacy, employing similar detection methods. In the in vivo experiment, sodium iodoacetate was injected to establish a rat knee OA model, followed by interventions including ALG-M2Exo. After 4 and 8 weeks, samples were collected for gross observation and histological staining to assess cartilage damage repair.

RESULTS

In the cell experiment, M2-Exo exhibited typical exosomal characteristics, directly promoting the proliferation of inflammatory chondrocytes, inhibiting their apoptosis, reducing the expression of TNF-α, iNOS, and MMP-13, and increasing the expression of IL-10 and COL II. RM2Mφ showed similar therapeutic effects on inflammatory chondrocytes as M2-Exo. In the in vivo experiment, the ALG-M2Exo group demonstrated superior repair effects on cartilage damage compared to other groups, with the treatment effect at 8 weeks being better than at 4 weeks.

CONCLUSION

ALG-M2Exo effectively promotes the repair of cartilage damage in OA through both a direct pathway by releasing M2-Exo that act on chondrocytes and an indirect pathway that facilitates the repolarization of M1Mφ to M2Mφ.

Dual-functional titanium implants via polydopamine-mediated lithium and copper co-incorporation: synergistic enhancement of osseointegration and antibacterial efficacy

Introduction

Orthopedic implant failure due to inadequate osseointegration and infection remains a critical challenge. To address this, we engineered a polydopamine (PDA)-mediated dual-functional platform for lithium (Li+) and copper (Cu2+) co-incorporation on titanium alloy (Ti6Al4V) implants, aiming to synergize osteogenic and antibacterial properties through a scalable surface modification strategy.

Methods

PDA coatings were polymerized onto polished Ti64 substrates, followed by sequential immersion in LiCl (800 μM) and CuCl2 (10 μM) solutions to construct Li+/Cu2+ co-doped surfaces (PDA@Li 800-Cu 10). In vitro assays assessed MC3T3-E1 pre-osteoblast proliferation (CCK-8), osteogenic differentiation (ALP activity, RT-PCR for ALP/Axin2), and antibacterial activity against S. aureus and E. coli (live/dead staining, CFU assays). In vivo efficacy was evaluated in a rat femoral defect model via micro-CT and histology.

Results and discussion

Li+-functionalized surfaces (PDA@Li 800) enhanced osteoblast proliferation and osteogenesis via Wnt/β-catenin activation. Cu2+-loaded coatings (PDA@Cu 10) eradicated >99% bacteria but moderately suppressed osteogenic markers. The dual-doped PDA@Li 800-Cu 10 surface resolved this bioactivity conflict, maintaining antibacterial efficacy comparable to PDA@Cu 10 while elevating the osteogenic capacity of Cu2+-only modified surfaces. In vivo, dual-modified implants eliminated bacterial colonization within 72 h and significantly increased peri-implant bone volume (BV/TV) in comparison to Ti64 controls, outperforming PDA-only counterparts. By harmonizing Li-driven osteoinduction and Cu-mediated bactericidal action through a scalable PDA platform, this work advances a transformative strategy for next-generation orthopedic and dental implants, simultaneously addressing infection risks and bone regeneration demands.

Associations between multiple metals exposure and bone mineral density: a population-based study in U.S. children and adolescents

AIM

This study examined the correlation between multi-metal exposure and bone mineral density (BMD) in U.S. children and adolescents.

METHODS

Data from 1,591 participants (aged 8-19) were analyzed using the National Health and Nutrition Examination Survey (NHANES) 2011-2016. We measured serum copper (Cu), selenium (Se), zinc (Zn), and blood lead (Pb), cadmium (Cd), mercury (Hg), manganese (Mn). Dual-energy X-ray absorptiometry assessed lumbar and total BMD. Advanced statistical approaches including weighted quantile sum (WQS) regression and bayesian kernel machine regression (BKMR) were employed to evaluate complex exposure interactions.

RESULTS

Blood Pb and serum Cu showed inverse associations with, while serum Se positively correlated with lumbar BMD (blood Pb: β: -0.013, serum Cu: β: -0.063, serum Se: 0.035) (all P < 0.05). The WQS index showed a significant association with both lumbar BMD(β = 0.019, P < 0.05) and total BMD (β = 0.019, P < 0.001). WQS analysis identified Cd, Se, and Hg as primary contributors to both lumbar and total BMD variations. BKMR models revealed nonlinear exposure-response relationships and synergistic effects between Cd and Mn.

CONCLUSION

These findings highlight the importance of considering mixed metal exposures in bone health assessments, providing crucial insights for developing preventive strategies to protect skeletal development in pediatric populations.

A promising approach to diabetic osteoporosis: oxymatrine's effects on gut microbiota and osteoblasts

OBJECTIVES

Oxymatrine (OMT), a quinolizidine alkaloid derived from Sophora flavescens Ait., has demonstrated therapeutic potential in type 2 diabetes mellitus (T2DM). This study aimed to investigate its effects on diabetic osteoporosis (DOP) and explore the underlying mechanisms involving gut microbiota and osteogenic regulation.

METHODS

In a rat model of T2DM, intragastric Oxymatrine was used to study trabecular bone repair through bone microstructure and histopathology analyses. Changes in gut microbiota, especially Gram-negative bacteria releasing lipopolysaccharides (LPS), were assessed via 16S rRNA sequencing. miRNA sequencing on LPS-induced rat osteoblasts, with and without Oxymatrine, explored osteoblast proliferation, mineralization, and the miR-539-5p/OGN/Runx2 pathway.

RESULTS

The administration of OMT resulted in an enhancement of diabetic osteopathy by reversing trabecular bone loss and modifying the composition of gut microbiota, specifically affecting Gram-negative bacteria that release LPS into the bloodstream. miRNA sequencing revealed that miR-539-5p, which was upregulated in LPS-induced ROBs, was downregulated following OMT treatment. Furthermore, OMT was found to promote osteoblast proliferation and mineralization under conditions of LPS exposure and modulate the miR-539-5p/OGN/Runx2 signaling pathway.

CONCLUSIONS

OMT improves diabetic osteoporosis by altering gut microbiota, decreasing LPS release, and enhancing osteoblast growth and differentiation through the miR-539-5p/OGN/Runx2 pathway, suggesting its potential as a treatment.

Reprogramming mitochondrial metabolism to enhance macrophages polarization by ROS-responsive nanoparticles for osteoarthritis

Osteoarthritis (OA) is a chronic low-grade inflammatory joint disease closely related to the inflammatory pathological microenvironment caused by synovial M1 macrophages. In contrast to the proinflammatory role of M1 macrophages, M2 macrophages contribute to anti-inflammatory responses and tissue repair. Therefore, shifting the M2/M1 phenotype ratio in favor of M2 macrophages has become a promising therapeutic strategy for OA. However, current therapeutics cannot penetrate the synovium and only show limited drug retention time. Herein, we developed an OA microenvironment-responsive nanocarrier with thioketal bonds in the main chain and β-1,3-d-glucan and triphenylphosphine units in the side chain, which can respond to reactive oxygen species (ROS) and target macrophages and mitochondrial aggregation. For OA treatment, 4-octyl itaconate and dexamethasone were encapsulated within the nanocarrier, forming HBPTG@OD that effectively eliminated mitochondrial ROS and inducible nitric oxide synthase in M1 macrophages. HBPTG@OD significantly suppressed the release of inflammatory factors by macrophages and thereby reducing chondrocyte death. In vivo studies in a destabilized medial meniscus (DMM)-induced OA model showed that HBPTG@OD effectively converted M1 synovial macrophages to M2 macrophages, consequently delaying chondrogenic apoptosis. This study presents a nanocarrier-based strategy that effectively repolarizes M1 macrophages, demonstrating great promise for the treatment of OA.

TBBPA induced hepatocyte ferroptosis by PCBP1-mediated ferritinophagy

Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant and has been identified as emerging widespread pollutants. Ferroptosis, a recently characterized form of iron-dependent cell death, is related to a wide range of liver diseases. Ferritinophagy as a novel selective form of autophagy functions in iron processing is essential to induce ferroptosis. Poly(rC)-binding protein 1 (PCBP1) is an iron chaperone involved in iron loading to ferritin. Nevertheless, the potential health risk caused by TBBPA in mammals is unknown. Thus, this study is conducted to explore the molecular mechanism of TBBPA-induced liver injury and the unique role of PCBP1 in it. In this study, we found that TBBPA exposure caused hepatic pathological injury and hepatocyte mitochondrial morphological changes, such as decreased or absent mitochondrial crest, ruptured mitochondrial membranes and mitochondrial shrinkage. The result showed that TBBPA exposure exacerbated glutathione depletion and lipid peroxidation, which are hallmarks of ferroptosis. Consistent with the results in vivo, TBBPA exposure activated ferritinophagy and upregulated indicators related to ferroptosis in hepatocytes. Of note, overexpression of PCBP1 inhibited TBBPA-induced ferroptosis by reducing overstimulated ferritinophagy. Here, we uncover a new mechanism whereby TBBPA triggers hepatocyte ferroptosis through the activation of ferritinophagy. Of note, we identify PCBP1 as critical for liver iron homeostasis, link this molecule to liver disease. Taken together, our findings provide a new therapeutic strategy and potential target for the treatment of liver disease.

Different Forms of Regulated Cell Death in Type-2-Diabetes-Mellitus-Related Osteoporosis: A Focus on Mechanisms and Therapeutic Strategies

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder with a high prevalence and challenging treatment options. It significantly affects the function of various organs, including bones, and imposes substantial social and economic costs. Chronic hyperglycemia, insulin resistance, and abnormalities in glucolipid metabolism can lead to cellular damage within the body. Bone dysfunction represents a significant characteristic of diabetic osteoporosis (DOP). Recent studies confirm that cell death is a critical factor contributing to bone damage. Regulated cell death (RCD) is a highly controlled process that involves numerous proteins and specific signaling cascades. RCD processes, including apoptosis, autophagy, necroptosis, pyroptosis, ferroptosis, and cuproptosis, may be linked to the dysfunction of bone cells in T2DM. In this review, the cell death types of bone cell populations during the pathogenic process of DOP were explored, and the link between cellular RCD processes and the pathogenesis of DOP was further explored. In addition, the research progress on targeting RCD for DOP was summarized in this paper. This may provide a foundation for additional explorations and drug development, as well as new therapeutic concepts for the clinical management of DOP.

Association between triglyceride‑glucose index and lumbar bone mineral density among Chinese individuals with osteoporotic fractures: a cross sectional study

Few studies have explored the association between the triglyceride-glucose (TyG) index and lumbar bone mineral density (BMD) across different skeletal sites in individuals with osteoporotic fractures (OPFs). The objective of this research was to investigate the relationship between the TyG index and lumbar BMD in individuals with OPFs. Conducted at the Affiliated Kunshan Hospital of Jiangsu University between January 2017 and March 2024, this retrospective cross-sectional study involved 950 OPFs patients requiring hospitalization or surgery. In this study, lumbar BMD the dependent variable, while the TyG index served as the independent variable. Generalized estimating equations (GEE) were used to evaluate the association between the TyG index and lumbar BMD levels. The generalized additive model (GAM) was employed to explore non-linear associations. In the all-adjusted models, a positive association was found between the TyG index and lumbar BMD among the patients with OPFs (β = 0.027; 95% confidence interval [CI] 0.011-0.042; P-value < 0.001). Similar results were observed across the four quantiles of the TyG index, Q4 (β = 0.045; 95% confidence interval [CI] 0.019-0.072; P-value < 0.001). A highly uniform pattern was noted across these findings. The evidence-based discovery of the relationship between the TyG index and lumbar BMD could inform clinical practices, particularly in the assessment and management of bone health in patients with OPFs.

Preparation and properties of chitosan quaternary ammonium salt/α-calcium sulfate hemihydrate/β-tricalcium phosphate composite bone cement

OBJECTIVE

The effective treatment of bone tissue defects is a significant challenge in clinical orthopaedics. This study investigated the preparation and properties of composite bone cements comprising 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC)-modified α-calcium sulfate hemihydrate (α-CSH)/β-tricalcium phosphate (β-TCP) for potential applications in bone regeneration.

METHODS

α-CSH was synthesised via a hydrothermal method, while β-TCP was prepared through a chemical reaction involving calcium salts and phosphates. HACC was dissolved in deionised water to formulate curing solutions with concentrations ranging from 0 to 4 wt% HACC. The α-CSH and β-TCP powders (7:3 mass ratio) were homogeneously blended with the HACC solution (1:0.3 w/v) to produce HACC/α-CSH/β-TCP composite bone cements. To assess the biocompatibility, osteogenic potential, and antimicrobial activity, extracts of the composite bone cements were used to culture rat bone marrow mesenchymal stem cells. A critical bone defect model in the femoral condyle of male Sprague-Dawley rats was employed to evaluate the in vivo osteogenic repair efficacy.

RESULTS

The self-curing time met clinical requirements, and the compressive strength approached that of normal human cancellous bone. The in vitro degradation rate was consistent with the rate of new bone formation. Increasing the HACC concentration enhanced the injectability and washout resistance of the composites. The materials exhibited good in vitro biocompatibility; composites containing HACC upregulated osteogenesis-related gene expression and significantly inhibited the growth of Staphylococcus aureus and Escherichia coli. In vivo, the 3 wt% HACC/α-CSH/β-TCP composite showed the best overall performance.

CONCLUSIONS

HACC/α-CSH/β-TCP composite bone cements demonstrate promising clinical potential owing to their improved setting time, mechanical properties, injectability, and cytocompatibility. This material is a strong candidate as a substitute for artificial bone to treat infectious bone defects.

Unraveling the Molecular Mechanisms of Osteoarthritis: The Potential of Polyphenols as Therapeutic Agents

The complex nature of osteoarthritis (OA), driven by the intricate interplay of genetic, environmental, and lifestyle factors, necessitates the development of a single treatment method, which is highly challenging. The long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids often leads to adverse side effects like kidney damage and stomach ulcers. Major health threats like obesity and aging create a milieu of chronic low-grade inflammation and increased mechanical stress on the joints resulting in cartilage deterioration. Additionally, postmenopausal women with lower circulating 17β-estradiol levels experience accelerated joint deterioration due to increased immune activity resulting in the increased production of pro-inflammatory cytokines, with elevated MMP expression and decreased type II collagen synthesis. Polyphenols are nature's gifted magic molecules, which possess diverse biological properties like anti-oxidant, anti-bacterial, anti-inflammatory, estrogenic, and insulin-sensitizing effects, which can manage and treat all the multi-factorial contributing factors of OA effectively. Certain polyphenols can act as phytoestrogens and mimic the effects of natural estrogen by binding to ERα and ERβ and can act as SERMs and prevent degradation of the articular cartilage thereby alleviating osteoarthritic conditions. These molecules downregulate the expression of various pro-inflammatory cytokines, apoptotic genes, and matrix-degrading proteases (MMPs) while upregulating major ECM proteins like type II collagen, aggrecan, and proteoglycans in various osteoarthritic animal models. This review provides a comprehensive overview of the molecular mechanisms involved in OA development and also explores the therapeutic potential of different polyphenols in mitigating joint inflammation and their protective effect in inhibiting the degradation of cartilage extracellular matrix (ECM) and enhancing joint homeostasis.

Bioactive phosphorus dendrimers deliver protein/drug to tackle osteoarthritis via cooperative macrophage reprogramming

Reprogramming imbalanced synovial macrophages and shaping an immune microenvironment conducive to bone and cartilage growth is crucial for efficient tackling of osteoarthritis (OA). Herein, we present a co-delivery nanosystem based on generation 2 (G2) hydroxyl-terminated bioactive phosphorus dendrimers (G2-OH24) that were loaded with both catalase (CAT) and quercetin (Que). The created G2-OH24/CAT@Que complexes exhibit a uniformly distributed spherical morphology with a size of 138.8 nm, possess robust stability, and induce macrophage reprogramming toward anti-inflammatory M2 phenotype polarization and antioxidation through cooperative CAT-catalyzed oxygen generation, Que-mediated mitochondrial homeostasis restoration, and inherent immunomodulatory activity of dendrimer. Such macrophage reprogramming leads to chondrocyte apoptosis inhibition and osteogenic differentiation of bone mesenchymal stem cells. Administration of G2-OH24/CAT@Que to an OA mouse model results in attenuation of pathological features such as cartilage degeneration, bone erosion, and synovitis through oxidative stress alleviation and inflammatory factor downregulation in inflamed joints. Excitingly, the G2-OH24/CAT@Que also polarized macrophages in adherent effusion monocytes (AEMs) extracted from joint cavity effusions of OA patients to M2 phenotype and downregulated reactive oxygen species levels in AEMs. This study suggests a promising nanomedicine formulation of phosphorus dendrimer-based co-delivery system to effectively tackle OA through the benefits of full-active ingredients of dendrimer, drug, and protein.

Dieckol ameliorates inflammatory response via inhibition of CHI3L1 expression in collagen-induced arthritis rats

BACKGROUND

Dieckol (DEK), the main phlorotannin of brown algal, has been regarded as a powerful anti-inflammatory agent in various diseases. Rheumatoid arthritis (RA) is a typical inflammatory autoimmune disease affecting synovial joints. However, the pharmaceutical effect of DEK on RA is still waiting to be unveiled.

METHODS

A collagen-induced arthritis (CIA) rat model was established and DEK was administered intraperitoneally for three weeks. Paw swelling and histologic analysis were performed to evaluate CIA progression. Inflammatory cytokine and oxidative biomarker expression were assessed by real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). Vascular endothelial growth factor A (VEGFA) expression in synovial joint was assessed by immunoblotting and immunofluorescent (IF) staining. TdT-mediated dUTP nick-end labeling (TUNEL) staining was used to evaluate chondrocyte apoptosis. Western blot assay was performed to determine the expression level of nuclear erythroid-derived 2-like 2 (Nrf2), chitinase 3-like protein 1(CHI3L1) and apoptosis-specific proteins. Finally, CHI3L1 overexpression was used to explore its essential role in the biological effect of DEK in vivo.

RESULTS

DEK treatment significantly ameliorates paw swelling, inflammatory cell infiltration, chondrocyte apoptosis and vascular pannus formation in CIA rats. Moreover, inflammatory cytokine and oxidative biomarker expression was also attenuated by DEK treatment. Notably, DEK treatment obviously promoted Nrf2 nuclear import and CHI3L1 expression in synovial joint. Overexpression of CHI3L1 by AVV-mediated transfection abrogated the pharmaceutical effect of DEK in vivo.

CONCLUSION

This study provides a promising translational potential of DEK as an anti-rheumatic drug facilitating RA clinical treatment.

Magnesium-induced strengthening, degradation and osteogenesis for additively manufactured Zn-Mg orthopedic implants

Additively manufactured biodegradable metals demonstrate great potential in orthopedic implants, enabling patient-specific designs and eliminating the need for secondary surgeries through degradation. Zinc (Zn)-magnesium (Mg) alloys reconcile the dilemma between Zn's low biological activity and Mg's rapid degradation, and become promising bone-repair materials. However, Zn-Mg alloys currently fabricated via additive manufacturing exhibit high strength but low ductility, and the effects and mechanisms by which Mg influences their degradation and bone regeneration remain unclear. Here, Zn-xMg alloys (x = 0, 0.1, 0.2, 0.4, 1.0 wt%) are prepared using laser powder bed fusion (L-PBF). Adding Mg refines the microstructure and forms brittle secondary phases, improving strength but reducing ductility. Zn-0.4Mg shows superior balance, with an ultimate tensile strength of 289.40 MPa and elongation of 12.53 %. The addition of Mg slows degradation by forming protective Mg-containing products and accelerating the passivation. Furthermore, Mg alloying significantly enhances bone regeneration, as indicated by both in vitro and in vivo tests. This improvement is driven by the release of less Zn2+ and more Mg2+, which promotes cytocompatibility and osteogenic differentiation. This study offers critical insights for optimizing Zn-based biodegradable metals and advancing the development of next-generation orthopedic implants. STATEMENT OF SIGNIFICANCE: Laser powder bed fusion (L-PBF) enables the fabrication of customized implants. Zn-Mg alloys are among the most promising materials for bone repair. However, Zn-Mg alloys fabricated by l-PBF exhibit high strength but low ductility, while the effects and mechanisms of Mg alloying on degradation and osteogenesis remain unclear. This study first fabricated Zn-Mg bulk materials (0-1 wt% Mg) via l-PBF, clarifying their microstructure and degradation products. Mg enhanced mechanical strength, with Zn-0.4Mg achieving a balanced combination of strength and ductility. Mg slowed degradation by forming protective Mg-containing products and accelerating passivation, while promoting osteogenesis by releasing more Mg2+ and less Zn2+. These findings offer valuable insights for optimizing Zn-based metals and developing next-generation biodegradable implants.

Fullerol Initiates Stem Cell-Nanomaterials Interactions for Enhanced Tissue Regeneration via Clathrin-Mediated Endocytosis and Nuclear Factor Erythroid 2-Related Factor 2 Signaling

The advancement of nanomedicine requires a thorough understanding of the intrinsic bioactivity and molecular interactions of nanomaterials for safe and effective clinical applications, which remains lacking for most currently developed nanomaterials. Here, we uncover the unique intrinsic bioactivity and regulatory mechanisms of carbon-based fullerol nanomaterials through high-throughput molecular analysis and explore their therapeutic potential for tissue regeneration using tissue engineering approaches. Fullerol exhibits intrinsic pro-differentiation and antioxidant properties that enhance the osteogenesis and chondrogenesis of MSCs. Mechanistically, proteomic analysis combined with small-molecule inhibition studies reveals that fullerol is internalized by MSCs via clathrin-mediated endocytosis and activates NRF2 signaling, thereby exerting antioxidant effects that restore impaired MSC viability and differentiation under oxidative stress. Leveraging these unique bioactivities, we develop a fullerol-functionalized hydrogel with feasible physicochemical properties and triple biological functions in antioxidant, pro-osteogenic, and pro-chondrogenic effects and confirm its great regenerative capacity for both cartilage and subchondral bone by promoting structural restoration and improving functional recovery in a rat osteochondral defect model. Our findings offer new insights into the intricate interactions between stem cells and nanomaterials at the cellular and molecular levels and broaden the potential biomedical applications of fullerol for future cartilage and bone regeneration therapies.

Mechanistic insights into cadmium-induced nephrotoxicity: NRF2-Driven HO-1 activation promotes ferroptosis via iron overload and oxidative stress in vitro

Cadmium (Cd), a pervasive environmental toxicant, poses significant threats to human and animal health through multi-organ toxicity. While ferroptosis has been implicated in Cd-induced pathologies, the molecular mechanisms underlying Cd-mediated nephrotoxicity remain poorly understood. This study elucidates the ferroptosis pathway in CdCl2-exposed PK-15 cells and murine kidney, characterized by iron overload, lipid peroxidation, and mitochondrial dysfunction, which were ameliorated by ferroptosis inhibitor ferrostatin-1. Transcriptomic analysis revealed substantial upregulation of heme oxygenase-1 (HO-1) following CdCl2 exposure. Mechanistically, CdCl2 triggered nuclear translocation of nuclear factor erythroid 2-related factor-2 (NRF2), subsequently activating HO-1 transcription. Over-activated HO-1 catalyzes the decomposition of heme and releases free iron, accompanied with the degradation of ferritin heavy chain 1 (FTH1) induced by CdCl2 exposure, which leads to intracellular iron overload and excessive lipid peroxides production through Fenton reaction, resulting in ferroptosis ultimately. In vivo validation confirmed NRF2/HO-1-mediated ferroptosis in CdCl2-induced murine nephrotoxicity. Both pre-treatment with HO-1 competitive inhibitor Zinc protoporphyrin IX (ZnPP) and knockout of HO-1 gene remarkably alleviated PK-15 cells against ferroptosis induced by CdCl2 treatment. Our findings demonstrate that Cd exposure initiates NRF2-mediated HO-1 overexpression, driving iron-dependent lipid peroxidation and subsequent ferroptosis. This mechanistic insight provides potential therapeutic targets for mitigating Cd-induced renal damage, advancing our understanding of heavy metal toxicity and its cellular consequences.

Magnesium as an emerging bioactive material for orthopedic applications: bedside needs lead the way from innovation to clinical translation

With the rapid increase in population aging, the number of surgical operations in orthopedics is expected to increase. The gap between the materials applied in clinical orthopedics and materials in discovery and research is obvious due to regulatory requirements for biosafety and treatment efficacy. For the bedside needs, it is important to overcome hurdles by achieving impactful innovation and clinical translation of orthopedic materials. Magnesium (Mg), as an emerging bioactive material, is one of the vital components of the human body and mainly stored in the musculoskeletal system as either a matrix component or an intracellular element for the homeostasis of various physiological functions. However, the degradation and biomechanical performance limit the applications of Mg. This review aims to explore the current challenges and future directions of Mg for clinical translation and provide an update on biomaterials used in orthopedics, factors driving orthopedic innovation, physiology of magnesium ions (Mg2+) and its potential clinical applications. To achieve orthopedic application, modification of the performance of Mg as implantable metals and function of the degradation products of Mg in vivo are described. For the clinical needs of treating the steroid-associated osteonecrosis (SAON), Mg screws and Mg-based composite porous scaffolds (Mg/PLGA/TCP: magnesium/poly(lactic-co-glycolic acid) (PLGA)/tricalcium phosphate (TCP)) have been developed, but the challenges of Mg-based implants in load-bearing skeletal sites still exist. To utilize the beneficial biological effects of Mg degradation and overcome the weakness in mechanical stability for fracture fixation, the concept of developing Mg/titanium (Ti) hybrid orthopedic implants is reported, where the Ti component provides effective mechanical support while the inclusion of Mg component potentially optimizes the biomechanical properties of Ti component and facilitate bone healing. This review provides a reference frame for the translation of novel materials and promotes the development of innovative orthopedic biomaterials for clinical applications.

A case report of implanted bone displacement after abscess formation

RATIONALE

Implanted bone is a commonly used filling material for bone defects, participating in the formation of new bone. Complications associated with implanted bone include nonunion, infection, etc. Few cases of implanted bone displacement through gravitational abscesses have been reported in the literature. This article aims to improve clinicians' recognition of this phenomenon and discuss preventive measures and treatment strategies for implant-associated infections.

PATIENT CONCERNS

A 7-year-old female patient was admitted to the hospital due to recurrent purulent fluid discharge from the incision site for 3 months following a right hip surgery 4 months ago. Wound secretion culture revealed a methicillin-resistant Staphylococcus aureus infection. The imaging before the first debridement in the external hospital showed that there were 2 high-density shadows around the right femoral greater trochanter, which were implanted bone.

DIAGNOSES

Implant-related infection and chronic osteomyelitis.

INTERVENTIONS

The implant and inflammatory lesions were removed through multiple surgeries and anti-infection treatment.

OUTCOMES

After 6 months of follow-up, there was no sign of infection in the wound.

LESSONS

It is rare-reported that implanted bone displacement is caused by factors such as abscess formation. Treatment and understanding of implanted bone around the greater trochanter of the right femur is important. Early recognition and surgical removal of displaced implanted bone play a crucial role in infection control and disease prognosis.

Prevotella copri-mediated caffeine metabolism involves ferroptosis of osteoblasts in osteoarthritis

There is a positive causality between coffee consumption and osteoarthritis (OA); however, whether gut microbiota is involved needs to be discussed. Here, we observed that in caffeine consumers, fecal Prevotella copri abundance was positively correlated with subchondral bone mass, serum caffeine concentration was negatively correlated with bone mass, and fecal P. copri was negatively correlated with serum caffeine. In the OA model, caffeine intake aggravated articular cartilage destruction, bone mass loss, and intestinal barrier damage; on the contrary, paraxanthine intake reversed the above lesions. Importantly, after the intestinal P. copri supplement, caffeine-induced lesions in OA mice were effectively alleviated. Mechanically, P. copri has the potential to metabolize caffeine into paraxanthine, and this effect could alleviate the ferroptosis of osteoblast in the OA model. This study screened out that P. copri, an endogenous bacteria, has the ability to metabolize caffeine and revealed its effects on OA progression.IMPORTANCEThere is positive causality between coffee consumption and osteoarthritis (OA). Caffeine exposure is responsible for the reduction of bone mass and restrained osteoblast function. Prevotella copri abundance is exhausted in gut and positively correlated with subchondral bone mass in coffee consumption patients with OA. Supplement of intestinal P. copri alleviates caffeine-induced subchondral bone loss. P. copri has the potential to metabolize caffeine into paraxanthine, and this effect alleviates ferroptosis of osteoblast. Our study illustrated that intestinal P. copri possibly serves as a novel promising treatment for coffee consumers with OA.