Nanoparticle-based inhibition of vascular endothelial growth factor receptors alleviates osteoarthritis pain and cartilage damage

The application of epigenetic clocks in degenerative musculoskeletal diseases: A systematic review

OBJECTIVE

Epigenetic clocks have emerged as powerful tools for quantifying biological aging. Degenerative musculoskeletal disorders (e.g., osteoarthritis [OA], osteoporosis) represent a group of age-related conditions characterized by progressive tissue deterioration. While their epidemiological association with aging is well-established, the precise relationship with epigenetic aging markers remains to be systematically elucidated. This review synthesizes current evidence on the application of epigenetic clocks as biomarkers and their clinical potential in managing these conditions.

METHODS

We systematically searched four major biomedical databases (PubMed, PMC, Web of Science, ScienceDirect) from inception through December 2024 for observational studies examining the association between the epigenetic clock and degenerative musculoskeletal diseases using controlled vocabulary (e.g., DNA methylation age) combined with disease-specific terms. The protocol was registered with PROSPERO (CRD42024623554).

RESULTS

After screening, 14 studies (case-control, cross-sectional, cohort) were included. We identified eight epigenetic clocks (based on cartilage, bone, and blood biomarkers) for assessing degenerative musculoskeletal diseases. DunedinPACE showed significant associations with chronic low back pain severity (r = 0.39-0.45) and functional impairment, while Horvath's clock revealed tissue-specific epigenetic aging in OA cartilage (ΔAge = 3.7 years). GrimAge exhibited the strongest correlations with chronic pain (ρ = 0.47) and mediated socioeconomic influences (β = 0.81).

CONCLUSIONS

This systematic review of 14 clinical studies establishes epigenetic clocks as promising biomarkers for degenerative musculoskeletal diseases. The differential associations observed across epigenetic metrics highlight the need for disease-specific algorithm development. Future research should prioritize longitudinal validation and mechanistic investigations into socioeconomic influences on epigenetic aging.

Cross-regulation of inflammation and metabolic mechanisms in osteoarthritis: recent advances bridging the gap to novel treatments

Osteoarthritis (OA) is a debilitating degenerative disease of the joints and one of the most prevalent joint disorders affecting millions of individuals worldwide. This disease is highlighted by significant morbidity owing to encumbering joint pain and functional impairment. OA ensues following disruption of normal homeostasis in the joint resulting from aging, metabolic changes, or as a consequence of joint injury (referred to as post-traumatic OA). These processes are largely driven by low-grade inflammation that gradually compromises the anabolic and protective activities of joint resident cells including chondrocytes, synovial fibroblasts (SFs) and immune cells. Ample research suggests that the process of cartilage deterioration is the endpoint of complex pathologic processes culminating with synovitis, subchondral bone sclerosis, osteophyte formation, aberrant remodeling, and ultimately articular cartilage degradation. There remains a great need for identifying early markers and a "window of opportunity" to enable timely interventions in OA. However, this effort is hampered by the complex nature of the disease and its comorbidities. Joint holistic approaches using recent unbiased multi-omic tools are currently at the forefront promising better understanding of OA development. Currently, there are no meaningful disease-modifying drugs to treat OA, with surgical procedures as the ultimate effective intervention for end stage OA patients. The disability, pain, and surgical costs associated with OA management position this disease among the costliest and onerous for our society. This mini review will highlight advances in the last two decades and major obstacles limiting progress in OA research with particular emphasis on metabolic and inflammatory comorbidities.

Celastrol loaded nanocomplex for painless tumor therapy via YAP inhibition

Cancer-related pain is prevalent and severely impairs patients' quality of life. However, conventional cancer therapies primarily target tumor cell destruction, often overlooking the management of cancer pain. Thus, there is an immediate necessity to develop therapeutic agents that can both suppress tumor growth and alleviate cancer pain. In this study, we report a celastrol (CEL)-based nanocomposites (PDA-BSA-MnO2-CEL) for pain-less cancer immunotherapy. Results from in vitro and in vivo experiments demonstrate the efficacy and mechanism of the nanocomposites in pain-less immunotherapy. MnO2 and CEL induce immunogenic cell death (ICD), mediating immunotherapy. Additionally, CEL significantly reduces the secretion of the immunosuppressive factor Yes-associated protein (YAP) within the tumor microenvironment, thereby enhancing the efficacy of immunotherapy. The downregulation of YAP leads to reduced expression of vascular endothelial growth factor (VEGF), inhibiting tumor growth and decreasing activation of the pain-associated VEGF receptor 1 (VEGFR1), thus providing an analgesic effect. Moreover, CEL reduces inflammatory pain by lowering levels of inflammatory factors in tumors. The design of this nanocomposites system integrates immunotherapy with cancer pain inhibition, offering a novel approach to patient-centered tumor therapy.

A cross-sectional study on the assessment of COLL11A1, VEGF, and GDF5 gene polymorphisms in Turkish patients with primary knee osteoarthritis

BACKGROUND

This study aimed to assess the relationships between knee OA (KOA) and the genes encoding collagen type XI-alpha1 (COL11A1), vascular endothelial growth factor (VEGF), and growth differentiation factor-5 (GDF-5), which have recently been investigated for their role in the pathophysiology of KOA in a Turkish Population.

METHODS

This study included 100 patients who underwent surgery for KOA at Pamukkale University Medical Faculty's Orthopedics and Traumatology clinics and 100 volunteers with knee pain but without radiological evidence of KOA as a control group. Knee radiographs were assessed, and blood samples were collected from both groups for gene polymorphism analysis, with a focus on COL11A1 rs4907986, COL11A1 rs1241164, VEGF rs833058, and GDF5 rs143383.

RESULTS

Our findings revealed no statistically significant difference between the KOA and control groups for COL11A1 rs4907986 and rs1241164. However, COL11A1 rs4907986 was found to be more common in women. The VEGF rs833058 polymorphism did not significantly differ between the KOA and control groups, although the equal distribution of homozygous polymorphisms in both groups suggests its potential utility in diagnostic considerations. Similarly, no significant difference was observed for the GDF-5 rs143383 polymorphism. However, this polymorphism was more frequent than the wild type in both groups, suggesting its potential association with KOA and its possible utility as an early diagnostic marker.

CONCLUSION

While no significant associations were found between COLL11A1, VEGF, or GDF-5 polymorphisms and KOA, the findings highlight the prevalence of GDF5 rs143383 in both groups, suggesting its potential role in the pathogenesis of KOA and its utility as a diagnostic marker. Further research is needed to better understand the genetic factors involved in KOA.

CLINICAL TRIAL NUMBER

Not applicable.

Neurovascularization inhibiting dual responsive hydrogel for alleviating the progression of osteoarthritis

Treating osteoarthritis (OA) associated pain is a challenge with the potential to significantly improve patients lives. Here, we report on a hydrogel for extracellular RNA scavenging and releasing bevacizumab to block neurovascularization at the osteochondral interface, thereby mitigating OA pain and disease progression. The hydrogel is formed by cross-linking aldehyde-phenylboronic acid-modified sodium alginate/polyethyleneimine-grafted protocatechuic acid (OSAP/PPCA) and bevacizumab sustained-release nanoparticles (BGN@Be), termed OSPPB. The dynamic Schiff base bonds and boronic ester bonds allow for injectability, self-healing, and pH/reactive oxygen species dual responsiveness. The OSPPB hydrogel can significantly inhibit angiogenesis and neurogenesis in vitro. In an in vivo OA model, intraarticular injection of OSPPB accelerates the healing process of condyles and alleviates chronic pain by inhibiting neurovascularization at the osteochondral interface. The injectable hydrogel represents a promising technique to treat OA and OA associated pain.

Osteoarthritis year in review 2024: Biology

Osteoarthritis (OA) research is a fast-growing and extremely wide field, in which a substantial increase in knowledge has been achieved over the last year. It covers many different topics, however, a PubMed search using the terms 'osteoarthritis' and 'biology' resulted in only a limited number of studies that were published between April 2023 and April 2024. In order to identify OA-relevant studies that focus on mechanistic studies of biological processes at the tissue, cellular, and molecular level, the following keywords were included as search terms: tissue interactions, single cell sequencing, transcriptomics, extracellular matrix, signaling, ion channels, and pain. The final selection of publications presented in this 'year in review' was influenced by the personal preferences of the authors, and eventually three larger key themes emerged: 1) Joint tissue interactions covering meniscus, subchondral bone, fat tissue, synovium, and synovial fluid. 2) Degeneration of the cartilage extracellular matrix and generation of bioactive fragments. 3) Receptors, ion channels, signaling pathways, and cellular metabolism. Many of the studies summarized here identified novel potential targets for OA treatment, and promising results were already obtained addressing these targets in different animal models. It will be exciting to see which findings can be translated into future clinical studies and eventually lead to novel treatment approaches for human OA.

Novel injectable adhesive hydrogel loaded with exosomes for holistic repair of hemophilic articular cartilage defect

Hemophilic articular cartilage damage presents a significant challenge for surgeons, characterized by recurrent intraarticular bleeding, a severe inflammatory microenvironment, and limited self-repair capability of cartilage tissue. Currently, there is a lack of tissue engineering-based integrated therapies that address both early hemostasis, anti-inflammation, and long-lasting chondrogenesis for hemophilic articular cartilage defects. Herein, we developed an adhesive hydrogel using oxidized chondroitin sulfate and gelatin, loaded with exosomes derived from bone marrow stem cells (BMSCs) (Hydrogel-Exos). This hydrogel demonstrated favorable injectability, self-healing, biocompatibility, biodegradability, swelling, frictional and mechanical properties, providing a comprehensive approach to treating hemophilic articular cartilage defects. The adhesive hydrogel, featuring dynamic Schiff base bonds and hydrogen bonds, exhibited excellent wet tissue adhesiveness and hemostatic properties. In a pig model, the hydrogel could be smoothly injected into the knee joint cartilage defect site and gelled in situ under fluid-irrigated arthroscopic conditions. Our in vitro and in vivo experiments confirmed that the sustained release of exosomes yielded anti-inflammatory effects by modulating macrophage M2 polarization through the NF-κB pathway. This immunoregulatory effect, coupled with the extracellular matrix components provided by the adhesive hydrogel, enhanced chondrogenesis, promoted the cartilage repair and joint function restoration after hemophilic articular cartilage defects. In conclusion, our results highlight the significant application potential of Hydrogel-Exos for early hemostasis, immunoregulation, and long-term chondrogenesis in hemophilic patients with cartilage injuries. This innovative approach is well-suited for application during arthroscopic procedures, offering a promising solution for addressing the complex challenges associated with hemophilic articular cartilage damage.

Identification of key biomarkers related to fibrocartilage chondrocytes for osteoarthritis based on bulk, single-cell transcriptomic data

Introduction

Osteoarthritis (OA) is a prevalent joint disease that severely impacts patients' quality of life. Due to its unclear pathogenesis and lack of effective therapeutic targets, discovering new biomarkers for OA is essential. Recently, the role of chondrocyte subpopulations in OA progression has gained significant attention, offering potential insights into the disease. This study aimed to explore the role of fibrocartilage chondrocytes (FC) in the progression of OA and identify key biomarkers related to FC.

Methods

We analyzed single-cell ribonucleic acid sequencing (scRNA-seq) data from samples of OA and normal cartilage, focusing on FC. Microarray data were integrated to identify differentially expressed genes (DEGs). We conducted functional-enrichment analyses, including Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO), and used weighted gene co-expression network analysis (WGCNA) and the least absolute shrinkage and selection operator (LASSO) algorithm to select biomarkers. A novel risk model for OA was constructed using these biomarkers. We then built a transcription factor (TF)-gene interaction network and performed immunohistochemistry (IHC) to validate protein expression levels of these biomarkers in cartilage samples.

Results

The study identified 545 marker genes associated with FC in OA. GO and KEGG analyses revealed their biological functions; microarray analysis identified 243 DEGs on which functional-enrichment analysis were conducted. Using WGCNA and LASSO, we identified six hub genes, on the basis of which we constructed a risk model for OA. In addition, correlation analysis revealed a close association between Forkhead Box (FoxO)-mediated transcription and these these biomarkers. IHC showed significantly lower protein levels of ABCA5, ABCA6 and SLC7A8 in OA samples than in normal samples.

Conclusion

This study used a multi-omics approach to identify six FC-related OA biomarkers (BCL6, ABCA5, ABCA6, CITED2, NR1D1, and SLC7A8) and developed an exploratory risk model. Functional enrichment analysis revealed that the FoxO pathway may be linked to these markers, particularly implicating ABCA5 and ABCA6 in cholesterol homeostasis within chondrocytes. These findings highlight ABCA family members as novel contributors to OA pathogenesis and suggest new therapeutic targets.

Development and Validation of Diagnostic Models for Transcriptomic Signature Genes for Multiple Tissues in Osteoarthritis

Background

Progress in research on expression profiles in osteoarthritis (OA) has been limited to individual tissues within the joint, such as the synovium, cartilage, or meniscus. This study aimed to comprehensively analyze the common gene expression characteristics of various structures in OA and construct a diagnostic model.

Methods

Three datasets were selected: synovium, meniscus, and knee joint cartilage. Modular clustering and differential analysis of genes were used for further functional analyses and the construction of protein networks. Signature genes with the highest diagnostic potential were identified and verified using external gene datasets. The expression of these genes was validated in clinical samples by Real-time (RT)-qPCR and immunohistochemistry (IHC) staining. This study investigated the status of immune cells in OA by examining their infiltration.

Results

The merged OA dataset included 438 DEGs clustered into seven modules using WGCNA. The intersection of these DEGs with WGCNA modules identified 190 genes. Using Least Absolute Shrinkage and Selection Operator (LASSO) and Random Forest algorithms, nine signature genes were identified (CDADC1, PPFIBP1, ENO2, NOM1, SLC25A14, METTL2A, LINC01089, L3HYPDH, NPHP3), each demonstrating substantial diagnostic potential (areas under the curve from 0.701 to 0.925). Furthermore, dysregulation of various immune cells has also been observed.

Conclusion

CDADC1, PPFIBP1, ENO2, NOM1, SLC25A14, METTL2A, LINC01089, L3HYPDH, NPHP3 demonstrated significant diagnostic efficacy in OA and are involved in immune cell infiltration.

Pain Management Strategies in Osteoarthritis

Pain is the major symptom of osteoarthritis (OA) and is an important factor in strategies to manage this disease. However, the current standard of care does not provide satisfactory pain relief for many patients. The pathophysiology of OA is complex, and its presentation as a clinical syndrome is associated with the pathologies of multiple joint tissues. Treatment options are generally classified as pharmacologic, nonpharmacologic, surgical, and complementary and/or alternative, typically used in combination to achieve optimal results. The goals of treatment are the alleviation of symptoms and improvement in functional status. Several studies are exploring various directions for OA pain management, including tissue regeneration techniques, personalized medicine, and targeted drug therapies. The aim of the present narrative review is to extensively describe all the treatments available in the current practice, further describing the most important innovative therapies. Advancements in understanding the molecular and genetic aspects of osteoarthritis may lead to more effective and tailored treatment approaches in the future.

Pain sensitivity genes as therapeutic targets in knee osteoarthritis: A comprehensive analysis

Pain sensitivity is a significant factor in knee osteoarthritis (KOA), influencing patient outcomes and complicating treatment. Genetic differences, particularly in pain-sensing genes (PSRGs), are known to contribute to the variability in pain experiences among KOA patients. This study aims to systematically analyze PSRGs in KOA to better understand their role and potential as therapeutic targets. We utilized bulk RNA-seq data from the GSE114007 and GSE169077 datasets to identify differentially expressed genes, with 20 genes found to be significantly altered. Key PSRGs, including PENK, NGF, HOXD1, and TRPA1, were identified using LASSO, SVM, and random forest algorithms. Further, KEGG and GO enrichment analyses revealed pathways such as "Neuroactive ligand-receptor interaction" and "ECM-receptor interaction," which were validated through external datasets. Single-cell RNA-seq analysis from GSE152805, GSE133449, and GSE104782 datasets demonstrated the heterogeneity and dynamic expression of PSRGs across different cell subpopulations in synovium, meniscus, and cartilage samples. UMAP and pseudotime analyses were used to visualize spatial distribution and developmental trajectories of these genes. The findings emphasize the critical roles of PSRGs in KOA, highlighting their potential as therapeutic targets and suggesting that integrating genetic information into clinical practice could significantly improve pain management and treatment strategies for KOA.