Cellular senescence in knee osteoarthritis: molecular mechanisms and therapeutic implications

Nicotinamide Adenine Dinucleotide-Loaded Lubricated Hydrogel Microspheres with a Three-Pronged Approach Alleviate Age-Related Osteoarthritis

Chondrocyte senescence, synovitis, and decreased level of lubrication play pivotal roles in the pathogenesis of age-related osteoarthritis (AROA). However, there are currently no effective therapeutic interventions capable of altering the progression of OA until it reaches advanced stages, necessitating joint replacement. In this study, lubricious and drug-loaded hydrogel microspheres were designed and fabricated by utilizing microfluidic technology for radical polymerization of chondroitin sulfate methacrylate and incorporating nicotinamide adenine dinucleotide (NAD)-loaded liposomes modified with lactoferrin that are positively charged. Mechanical, tribological, and drug release analyses demonstrated enhanced lubrication properties and an extended drug dissemination time for the NAD@NPs@HM microspheres. In vitro assays unveiled the ability of NAD@NPs@HM to counteract chondrocyte senescence. RNA sequencing analysis, untargeted metabolomics analysis, and in vitro experiments on macrophages revealed that NAD@NPs@HM can regulate the metabolic reprogramming of synovial macrophages, promoting their repolarization from the M1 to M2 phenotype, thereby alleviating synovitis. Intra-articular injection of NAD@NPs@HM in aged mice reduced the mechanisms associated with AROA. These results suggest that NAD@NPs@HM may provide extended drug release, improved joint lubrication leading to better gait, and attenuation of AROA pathogenic processes, indicating its potential as a therapeutic approach for AROA.

Development of Reliable and High-Throughput Human Biomimetic Cartilage and Bone Models to Explore Senescence and Personalized Osteoarthritis Treatment Options

To facilitate effective preclinical testing of senescence treatments for osteoarthritis (OA), we have created reliable biomimetic and high-throughput models using aged human joint tissues. Moreover, concerns regarding scalability led to the concurrent development of a high-throughput human in vitro senescence cartilage organoid model. Osteochondral explants and cells for the cartilage organoid model were isolated from patients undergoing joint replacement surgery due to OA. To induce senescence, explants and organoids were subjected to radiation and/or mechanical loading. Samples were harvested; gene expression of relevant senescent and cartilage genes was measured using RT-qPCR, and protein expression was evaluated using histology. A general senescence phenotype was induced by the perturbations, as shown by senescence-associated β-galactosidase staining. In-depth gene expression analysis revealed that hyperphysiological mechanical loading upregulated gene expression of IL8 and SERPINE1, representing aspects of a senescence-associated secretory phenotype (SASP) profile. Irradiation upregulated CDKN1A, encoding p21, and downregulated LMNB1, representing a cell cycle arrest profile with the absence of a SASP response. Combining the two perturbations showed upregulation of CDKN1A, IL8, and SERPINE and downregulation of LMNB1, representing a complementary senescence model. The high-throughput human in vitro cartilage organoid senescence model showed similar effects to the irradiation explant model. In this study, we present a variety of senescence models of human aged chondrocytes that allows for rapid initial screening of anti-senescence compounds in high-throughput, as well as in-depth, characterization of post-mitotic aged chondrocytes prone to OA pathophysiology. This research advances the development of essential therapeutics for OA.

Latest developments of microphysiological systems (MPS) in aging-related and geriatric diseases research: A review

Aging is a gradual and irreversible process accompanied by the decline in tissue function and a significantly increased risk of various aging-related and geriatric diseases. Especially in the paradoxical context of accelerated global aging and the widespread emergence of pandemics, aging-related and geriatric diseases have become leading causes of individual mortality and disability, drawing increasing attention from researchers and investors alike. Despite the utility of current in vitro systems and in vivo animal models for studying aging, these approaches are limited by insurmountable inherent constraints. In response, microphysiological systems (MPS), leveraging advances in tissue engineering and microfluidics, have emerged as highly promising platforms. MPS are capable of replicating key features of the tissue microenvironment within microfabricated devices, offering biomimetic tissue culture conditions that enhance the in vitro simulation of intact or precise human body structure and function. This capability improves the predictability of clinical trial outcomes while reducing time and cost. In this review, we focus on recent advancements in MPS used to study age-related and geriatric diseases, with particular emphasis on the application of organoids and organ-on-a-chip technologies in understanding cardiovascular diseases, cerebrovascular diseases, neurodegenerative diseases, fibrotic diseases, locomotor and sensory degenerative disorders, and rare diseases. And we aim to provide readers with critical guidelines and an overview of examples for modeling age-related and geriatric diseases using MPS, exploring mechanisms, treatments, drug screening, and other subsequent applications, from a physiopathological perspective, emphasizing the characteristic of age-related and geriatric diseases and their established correlations with the aging process. We also discuss the limitations of current models and propose future directions for MPS in aging research, highlighting the potential of interdisciplinary approaches to address unresolved challenges in the field.

Does Advanced Osteoarthritis Mimic Neuropathic Joint?

Introduction

Osteoarthritis (OA) is a prevalent condition among the elderly and leads to pain and functional limitations. Radiographic imaging often fails to correlate with symptom severity, and advanced OA may exhibit features reminiscent of neuropathic joints. This study explored the clinicopathological and histopathological correlations between advanced OA and neuropathic joints, hypothesizing clinical similarities.

Methods

A retrospective study involving 43 patients who underwent total knee arthroplasty for advanced knee OA was conducted from 2016 to 2020. Clinical, radiological, and histopathological evaluations were performed. Advanced OA was defined as an Ahlbach grade IV or above. The functional Knee Society Score (KSS) was used to assess clinical severity, and histopathology was considered "significant" if the results were consistent with the neuropathic joint findings. The statistical analyses included univariate and binary logistic regression analyses.

Results

The mean age was 57.63 ± 17.13 years, and most patients were females (69.77%). A total of 53.49% of the grading systems yielded histopathological findings resembling those of neuropathic joints. Univariate analysis revealed significant correlations between histopathology and the functional KSS, Ahlbach grade, and NRS score (p < 0.01). Binary logistic regression confirmed that KSS (< 40) and NRS score (< 7) were significant predictors (p < 0.001, Nagelkarke R 2  = 0.576).

Conclusion

Patients with advanced knee OA may exhibit characteristics resembling those of neuropathic joints, particularly individuals with a poorer functional knee. Thorough assessments are crucial for distinguishing between primary OA and neuropathic joint pathology and for carrying out more precise management strategies. This study provides valuable insights into the complex presentation of advanced knee OA and highlights the importance of using more constrained prosthesis and long stem components for potentially better outcomes.

The miR-6779/XIAP axis alleviates IL-1β-induced chondrocyte senescence and extracellular matrix loss in osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a long-term degenerative joint disease worsening over time. Aging and chondrocyte senescence contribute to OA progression. MicroRNAs have been confirmed to regulate different cellular processes. They contribute to OA pathology and may help to identify novel biomarkers and therapies for OA.

METHODS

This study used bioinformatics and experimental investigations to analyze and validate differentially expressed miRNAs in OA that might affect chondrocyte apoptosis and senescence.

RESULTS

miR-6779 was found to be significantly down-regulated in OA. Seventy-six of the predicted and miR-6779 targeted genes and the OA-associated disease genes overlapped, and these were enriched in cell proliferation, cell apoptosis, and cell cycle. miR-6779 overexpression remarkably attenuated IL-1β effects on chondrocytes by reducing MMP3 and MMP13 levels, promoting cell apoptosis, suppressing cell senescence, and increasing caspase-3, caspase-9 and reducing P16 and P21 levels. miR-6779 targeted inhibition of X-linked inhibitor of apoptosis protein (XIAP) expression. XIAP knockdown partially improved IL-1β-induced chondrocyte senescence and dysfunction. Lastly, when co-transfected with a miR-6779 agomir, the XIAP overexpression vector partially attenuated the effects of miR-6779 overexpression on chondrocytes; miR-6779 improved IL-1β-induced senescence and dysfunction in chondrocytes through targeting XIAP.

CONCLUSION

miR-6779 is down-regulated, and XIAP is up-regulated in OA cartilage and IL-1β-treated chondrocytes. miR-6779 inhibits XIAP expression, thereby promoting senescent chondrocyte cell apoptosis and reducing chondrocyte senescence and ECM loss through XIAP.

The efferocytosis process in aging: Supporting evidence, mechanisms, and therapeutic prospects for age-related diseases

BACKGROUND

Aging is characterized by an ongoing struggle between the buildup of damage caused by a combination of external and internal factors. Aging has different effects on phagocytes, including impaired efferocytosis. A deficiency in efferocytosis can cause chronic inflammation, aging, and several other clinical disorders.

AIM OF REVIEW

Our review underscores the possible feasibility and extensive scope of employing dual targets in various age-related diseases to reduce the occurrence and progression of age-related diseases, ultimately fostering healthy aging and increasing lifespan. Key scientific concepts of review Hence, the concurrent implementation of strategies aimed at augmenting efferocytic mechanisms and anti-aging treatments has the potential to serve as a potent intervention for extending the duration of a healthy lifespan. In this review, we comprehensively discuss the concept and physiological effects of efferocytosis. Subsequently, we investigated the association between efferocytosis and the hallmarks of aging. Finally, we discuss growing evidence regarding therapeutic interventions for age-related disorders, focusing on the physiological processes of aging and efferocytosis.

ABCA6 Regulates Chondrogenesis and Inhibits Joint Degeneration via Orchestrated Cholesterol Efflux and Cellular Senescence

Patellar dysplasia (PD) can cause patellar dislocation and subsequent osteoarthritis (OA) development. Herein, a novel ABCA6 mutation contributing to a four-generation family with familiar patellar dysplasia (FPD) is identified. In this study, whole exome sequencing (WES) and genetic linkage analysis across a four-generation lineage presenting with six cases of FPD are conducted. A disease-causing mutation in ABCA6 is identified for FPD. Further analyses reveal a consistent correlation between ABCA6 expression downregulation and PD occurrence, chondrocyte degeneration, and OA onset. Moreover, ABCA6-KO mice demonstrate severe knee joint degeneration and accelerated OA progression. Besides, synovial mesenchymal stem cells (SMSCs) are extracted from WT, ABCA6-/+, and ABCA6-/- mice to create chondrogenic organoids in vitro, confirming ABCA6 deficiency can lead to chondrocyte degeneration via modulating cell cycle and activating cellular senescence. Moreover, transcriptome and metabolomic sequencing analysis on ABCA6-KO chondrocytes unveils that the ABCA6 deficiency inhibits cholesterol efflux, leading to intracellular cholesterol accumulation and subsequent cellular senescence and impaired chondrogenesis.A disease-causing mutation of ABCA6 is identified for FPD. ABCA6 is correlated with PD occurrence and subsequent OA progression. ABCA6 can serve as a potential target in chondrogenesis and OA treatment by orchestrated intracellular cholesterol efflux and delayed cellular senescence.

sdRNA-D43 derived from small nucleolar RNA snoRD43 improves chondrocyte senescence and osteoarthritis progression by negatively regulating PINK1/Parkin-mediated mitophagy pathway via dual-targeting NRF1 and WIPI2

BACKGROUND

Chondrocyte senescence play an essential role in osteoarthritis (OA) progression. Recent studies have shown that snoRNA-derived RNA fragments (sdRNAs) are novel regulators of post-transcriptional gene expression. However, the expression profiles and their role in post-transcriptional gene regulation in chondrocyte senescence and OA progression is unknown. Here, we determined sdRNAs expression profile and explored sdRNA-D43 role in OA and its mechanism.

METHODS

We used qPCR arrays to determine sdRNAs expression in the chondrocytes of areas undamaged and damaged of the three knee OA samples. SdRNA-D43 expression was determined using quantitative reverse transcription-polymerase chain reaction and in situ hybridization. Then, bioinformatics analysis was conducted on the target genes that might be silenced by sdRNA-D43. Primary chondrocytes of damaged regions of knee OA samples were transfected with a sdRNA-D43 inhibitor or mimic to determine their functions, including in relation to mitophagy and chondrocyte senescence. Argonaute2-RNA immunoprecipitation and luciferase reporter assays were conducted to determine the target gene of sdRNA-D43. In a rat OA model induced by monosodium iodoacetate, adeno-associated virus sh-rat-sdRNA-D43 was injected into the knee joint cavity to assess its in vivo effects.

RESULTS

sdRNA-D43 expression were upregulated in damaged areas of knee OA cartilage with increased senescent chondrocytes. sdRNA-D43 inhibited mitophagy and promoted chondrocytes senescence during OA progression. Mechanistically, sdRNA-D43 silenced the expression of both NRF1 and WIPI2 by binding to their 3'-UTR in an Argonaute2‑dependent manner, which inhibited PINK1/Parkin-mediated pathway. Additionally, injection of AAV-sh-sdRNA-D43 alleviated the progression of OA in a monosodium iodoacetate-induced rat model.

CONCLUSION

Our results reveal an important role for a novel sdRNA-D43 in OA progression. sdRNA-D43 improves chondrocyte senescence by negatively regulating PINK1/Parkin-mediated mitophagy pathway via dual-targeting NRF1 and WIPI2, which provide a potential therapeutic strategy for OA treatment.

The potential molecular markers of inflammatory response in KOA with AD based on single-cell transcriptome sequencing analysis and identification of ligands by virtual screening

Alzheimer's disease (AD) and osteoarthritis (OA) are both senile degenerative diseases. Clinical studies have found that OA patients have a significantly increased risk of AD in their later life. This study hypothesized that chronic aseptic inflammation might lead to AD in KOA patients. However, current research has not yet clarified the potential mechanism between AD and KOA. Therefore, this study intends to use KOA transcriptional profiling and single-cell sequencing analysis technology to explore the molecular mechanism of KOA affecting AD development, and screen potential molecular biomarkers and drugs for the prediction, diagnosis, and prognosis of AD in KOA patients. It was found that the higher the expression of TXNIP, MMP3, and MMP13, the higher the risk coefficient of AD was. In addition, the AUC of TXNIP, MMP3, and MMP13 were all greater than 0.70, which had good diagnostic significance for AD. Finally, through the virtual screening of core proteins in FDA drugs and molecular dynamics simulation, it was found that compound Cobicistat could be targeted to TXNIP, Itc could be targeted to MMP3, and Isavuconazonium could be targeted to MMP13. To sum up, TXNIP, MMP3, and MMP13 are prospective molecular markers in KOA with AD, which could be used to predict, diagnose, and prognosis.

Engineered MSC-sEVs as a Versatile Nanoplatform for Enhanced Osteoarthritis Treatment via Targeted Elimination of Senescent Chondrocytes and Maintenance of Cartilage Matrix Metabolic Homeostasis

Chondrocyte senescence is an important pathogenic factor causing osteoarthritis (OA) progression through persistently producing pro-inflammatory factors. Mesenchymal stem cells-derived small extracellular vesicles (MSC-sEVs) have shown anti-inflammatory effects in OA models, while persistent existence of senescent chondrocytes still promotes cartilage destruction. Therefore, improving the targeted elimination ability on senescent chondrocytes is required to facilitate the translation of MSC-sEVs in OA treatment. In this study, versatile engineered MSC-sEVs are developed to targetedly clear senescent chondrocytes and maintain cartilage metabolic homeostasis. Specifically, MSC-sEVs are loaded with siRNA mouse double minute 2 homologue (siMDM2) and modified with cartilage-targeting peptide WYRGRL-PEG2K-DSPE (WPD), named WPD-sEVssiMDM2. The results demonstrate versatile modification improves the cellular uptake of MSC-sEVs in chondrocytes, and thus improves the antiaging effects. Importantly, multifunctional modification enhances cartilage penetration ability and extends joint retention time of MSC-sEVs. In both post-traumatic OA mice and naturally aged mice, WPD-sEVssiMDM2 more effectively eliminates senescent chondrocytes and maintained matrix metabolic homeostasis. By using the P53 phosphorylation inhibitor, the essential role MDM2-P53 pathway in the antiaging function of WPD-sEVssiMDM2 on chondrocytes is verified. In ex vivo cultured human OA cartilage explants, it is confirmed that WPD-sEVssiMDM2 alleviates senescent phenotype. Altogether, the findings suggest that WPD-sEVssiMDM2 have promising translational potential for OA treatment.

Menopause-induced 17β-estradiol and progesterone loss increases senescence markers, matrix disassembly and degeneration in mouse cartilage

Female individuals who are post-menopausal present with higher incidence of knee osteoarthritis (KOA) than male counterparts; however, the mechanisms underlying this disparity are unknown. The most commonly used preclinical models lack human-relevant menopausal phenotypes, which may contribute to our incomplete understanding of sex-specific differences in KOA pathogenesis. Here we chemically induced menopause in middle-aged (14-16 months) C57/BL6N female mice. When we mapped the trajectory of KOA over time, we found that menopause aggravated cartilage degeneration relative to non-menopause controls. Network medicine analyses revealed that loss of 17β-estradiol and progesterone with menopause enhanced susceptibility to senescence and extracellular matrix disassembly. In vivo, restoration of 17β-estradiol and progesterone in menopausal mice protected against cartilage degeneration compared to untreated menopausal controls. Accordingly, post-menopausal human chondrocytes displayed decreased markers of senescence and increased markers of chondrogenicity when cultured with 17β-estradiol and progesterone. These findings implicate menopause-associated senescence and extracellular matrix disassembly in the sex-specific pathogenesis of KOA.

GATD3A-deficiency-induced mitochondrial dysfunction facilitates senescence of fibroblast-like synoviocytes and osteoarthritis progression

Accumulating evidence indicates that cellular senescence is closely associated with osteoarthritis. However, there is limited research on the mechanisms underlying fibroblast-like synoviocyte senescence and its impact on osteoarthritis progression. Here, we elucidate a positive correlation between fibroblast-like synoviocyte senescence and osteoarthritis progression and reveal that GATD3A deficiency induces fibroblast-like synoviocyte senescence. Mechanistically, GATD3A deficiency enhances the binding of Sirt3 to MDH2, leading to deacetylation and decreased activity of MDH2. Reduced MDH2 activity impairs tricarboxylic acid cycle flux, resulting in mitochondrial dysfunction and fibroblast-like synoviocyte senescence. Intra-articular injection of recombinant adeno-associated virus carrying GATD3A significantly alleviates the osteoarthritis phenotype in male mice. This study increases our current understanding of GATD3A function. In particular, we reveal a novel mechanism of fibroblast-like synoviocyte senescence, suggesting that targeting GATD3A is a potential therapeutic approach for osteoarthritis.

Lactate-upregulated ARG2 expression induces cellular senescence in fibroblast-like synoviocytes of osteoarthritis via activating the mTOR/S6K1 signaling pathway

Cellular senescence was implicated in the pathogenesis of age-related diseases such as osteoarthritis (OA). Increasing evidence suggests that alterations in the OA joint microenvironment play a crucial role in the pathogenesis of OA. This study aims to establish a clear link between the impact of accumulated lactate on the senescence of fibroblast-like synoviocytes (FLS) within the OA microenvironment. OA models and models with intra-articular injection of lactate were established in rat models, histological analyses were performed. Human OA-FLS treated with lactate was analyzed by mRNA sequencing, senescence related experiments and underlying signaling pathway activation were comprehensively evaluated. This study confirmed that OA models and lactate-injection models exhibited higher synovitis scores. Enrichment analyses indicated dysregulated cell cycle and cellular senescence pathways in OA-FLS treated with lactate. Lactate significantly up-regulated arginase 2 (ARG2) expression and promoted OA-FLS senescence, including G1/S arrest, increased reactive oxygen species and β-galactosidase production, high expression of senescence-associated secretory phenotype factors, which could be attenuated by siRNA-Arg2. The ARG2-mTOR/S6K1 axis was identified as a potential signaling for lactate-induced OA-FLS senescence, and activated mTOR/S6K1 signaling could be reduced by siRNA-Arg2, rapamycin (mTOR inhibitor), and LY294002 (PI3K inhibitor). Our study provides novel targets and insights for OA therapies.

Forsythoside A mitigates osteoarthritis and inhibits chondrocyte senescence by promoting mitophagy and suppressing NLRP3 inflammasome via the Nrf2 pathway

BACKGROUND

Chondrocyte senescence and inflammation are hallmarks of osteoarthritis (OA). Forsythiaside A (FTA), a phenylethanol glycoside isolated from air-dried fruits of Forsythia, has been reported to have significant anti-inflammatory and antioxidant properties. However, its protective effects against OA have not been elucidated.

PURPOSE

We explored the therapeutic efficacy of FTA in inhibiting chondrocyte senescence and inflammation during OA, as well as the potential underlying mechanisms.

STUDY DESIGN

This study aimed to investigate the novel mechanism of FTA in alleviating OA in both cell and animal models.

METHODS

The protective effect of FTA against tert‑butyl hydroperoxide-induced chondrocyte damage was assessed, and the effects of FTA on cartilage aging and OA progression were evaluated using a medial meniscus (DMM)-induced knee OA mouse model. The regulatory effects of FTA on the NLRP3 Inflammasome, mitophagy, and the PKC/Nrf2 pathway were also explored.

RESULTS

In vitro, FTA improved mitochondrial function, enhanced mitophagy, suppressed NLRP3 inflammasome activation, and inhibited chondrocyte senescence; however, these chondroprotective effects were partially reversed after mitophagy inhibition, NLRP3 inflammasome activation, and Nrf2 pathway inhibition. Furthermore, we found that FTA directly interacts with Nrf2 and enhances its phosphorylation by protein kinase C (PKC). In vivo, FTA attenuated the pathological signs of knee OA in a DMM-model mouse model, which was partially reversed by ML385.

CONCLUSION

FTA inhibited chondrocyte senescence and OA progression by activating the PKC-Nrf2 pathway. Thus, FTA is a potential novel therapeutic agent for OA.

ER stress-induced YAP upregulation leads to chondrocyte phenotype loss in age-related osteoarthritis

Background

Osteoarthritis (OA) is a common degenerative joint disease, leading to pain and restricted mobility. Age-related endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of OA, but the underlying mechanisms remain unclear. This study aims to explore the relationship between age-related ER stress, YAP overexpression, and chondrocyte phenotype loss in the development of OA.

Methods

Cartilage samples were collected from patients undergoing amputation, and age-related ER stress markers and YAP expression were assessed using immunohistochemical staining and qPCR. Transgenic mice with cartilage-specific YAP overexpression (YAPOE) were created, and Pamrevlumab was administered to evaluate its therapeutic effects.

Results

Higher expression of ER stress markers and YAP were showed in aged tissues compared to younger tissues. YAP overexpression led to decreased levels of cartilage phenotype markers and increased osteogenesis-related proteins. In vivo, YAPOE mice exhibited OA-like cartilage degeneration, which was mitigated by Pamrevlumab treatment.

Conclusion

Age-related ER stress induces YAP overexpression, contributing to OA pathogenesis. Pamrevlumab effectively prevents this phenotype loss in YAPOE mice, suggesting its potential as a therapeutic agent for OA. These findings provide new insights into the molecular mechanisms of OA and highlight the importance of targeting the ER stress-YAP-CTGF signaling pathway in OA treatment and prevention.

Ferroptosis in Osteoarthritis: Current Understanding

Osteoarthritis (OA) is a prevalent degenerative disease in elderly people that is characterized by cartilage loss and abrasion, leading to joint pain and dysfunction. The aetiology of OA is complicated and includes abnormal mechanical stress, a mild inflammatory environment, chondrocyte senescence and apoptosis, and changes in chondrocyte metabolism. Ferroptosis is a regulated cell death modality characterized by the excessive accumulation of lipid peroxidation and mitochondrial dysfunction. The role of ferroptosis in OA pathogenesis has aroused researchers' attention in the past two years, and there is mounting evidence indicating that ferroptosis is destructive. However, the impact of ferroptosis on OA and how the regulators of ferroptosis affect OA development are unclear. Here, we reviewed the current understanding of ferroptosis in OA pathogenesis and summarized several drugs and compounds targeting ferroptosis in OA treatment. The accumulation of intracellular iron, the trigger of Fenton reaction, the excessive production of ROS, the peroxidation of PUFA-PLs, and mitochondrial and membrane damage are involved in chondrocyte ferroptosis. System Xc - and GPX4 are the most important regulators that control ferroptosis. Several compounds, such as DFO and Fer-1, have been proven effective in preventing ferroptosis and slowing OA progression on animal models. Collectively, targeting ferroptosis shows great potential in treating OA.

β-Hydroxybutyrate enhances chondrocyte mitophagy and reduces cartilage degeneration in osteoarthritis via the HCAR2/AMPK/PINK1/Parkin pathway

Osteoarthritis (OA) is widely recognized as the prevailing joint disease associated with aging. The ketogenic diet (KD) has been postulated to impede the advancement of various inflammatory ailments. β-Hydroxybutyrate (βOHB), a prominent constituent of ketone bodies, has recently been proposed to possess crucial signaling capabilities. In this study, we propose to explore the role and mechanism of βOHB in OA. Tissue staining and inflammatory factor assay were employed to evaluate the impacts of KD and βOHB on OA rats. The oxidative stress conditions in chondrocytes were induced using tert-butyl hydroperoxide (TBHP). The mechanisms were determined using the siRNA of hydroxycarboxylic acid receptor 2 (HCAR2), the antagonist of adenosine monophosphate-activated protein kinase (AMPK), and the inhibitor of mitophagy. The administration of KD demonstrated a reduction in pathological damage to cartilage, as well as a decrease in plasma levels of inflammatory factors. Furthermore, it resulted in an increase in the concentration of βOHB in the blood and synovial fluid. In vitro experiments showed that βOHB facilitated mitophagy and adenosine triphosphate production. Besides, βOHB mitigated chondrocyte senescence, inflammatory factors secretion, extracellular matrix degradation, and apoptosis induced by TBHP. Subsequent investigations indicated that the protective effects of βOHB were no longer observed following the knockdown of HCAR2, the antagonist of AMPK, or the inhibitor of mitophagy. Moreover, in vivo studies suggested that βOHB played a protective role by targeting the HCAR2-AMPK-PINK1 axis. In conclusion, βOHB enhanced chondrocyte mitophagy through the HCAR2/AMPK/PINK1/Parkin pathway, offering a potential therapeutic approach for the treatment of OA.

ESC-sEVs alleviate non-early-stage osteoarthritis progression by rejuvenating senescent chondrocytes via FOXO1A-autophagy axis but not inducing apoptosis

Osteoarthritis (OA) is a common joint degenerative disease which currently lacks satisfactory disease-modifying treatments. Oxidative stress-mediated senescent chondrocytes accumulation is closely associated with OA progression, which abrogates cartilage metabolism homeostasis by secreting senescence-associated secretory phenotype (SASP) factors. Numerous studies suggested mesenchymal stem cells-derived small extracellular vesicles (MSC-sEVs) have been regarded as promising candidates for OA therapy. However, MSC-sEVs were applied before the occurrence of cartilage degeneration or at early-stage OA, while in clinical practice, most OA patients who present with pain are already in non-early-stage. Recently, embryonic stem cells-derived sEVs (ESC-sEVs) have been reported to possess powerful anti-aging effects. However, whether ESC-sEVs could attenuate non-early-stage OA progression remains unknown. In this study, we demonstrated ESC-sEVs ameliorated senescent phenotype and cartilage destruction in both mechanical stress-induced non-early-stage posttraumatic OA and naturally aged mice. More importantly, we found ESC-sEVs alleviated senescent phenotype by rejuvenating aged chondrocytes but not inducing apoptosis. We also provided evidence that the FOXO1A-autophagy axis played an important role in the anti-aging effects of ESC-sEVs. To promote clinical translation, we confirmed ESC-sEVs reversed senescent phenotype in ex-vivo cultured human end-stage OA cartilage explants. Collectively, our findings reveal that ESC-sEVs-based therapy is of high translational value in non-early-stage OA treatment.

Advances in targeted therapies for age-related osteoarthritis: A comprehensive review of current research

Osteoarthritis (OA) is a common degenerative joint disease that disproportionately impacts the elderly population on a global scale. As aging is a significant risk factor for OA, there is a growing urgency to develop specific therapies that target the underlying mechanisms of aging associated with this condition. This summary seeks to offer a thorough introduction of ongoing research efforts aimed at developing therapies to combat senescence in the context of OA. Cellular senescence plays a pivotal role in both the deterioration of cartilage integrity and the perpetuation of chronic inflammation and tissue remodeling. Consequently, targeting SnCs has emerged as a promising therapeutic approach to alleviate symptoms and hinder the progression of OA. This review examines a range of approaches, including senolytic drugs targeting SnCs, senomorphics that modulate the senescence-associated secretory phenotype (SASP), and interventions that enhance immune system clearance of SnCs. Novel methodologies, such as utilizing novel materials for exosome delivery and administering anti-aging medications with precision, offer promising avenues for the precise treatment of OA. Accumulating evidence underscores the potential of targeting senescence in OA management, potentially facilitating the development of more effective and personalized therapeutic interventions.

Deferoxamine alleviates chondrocyte senescence and osteoarthritis progression by maintaining iron homeostasis

BACKGROUND

Osteoarthritis (OA) is a prevalent age-related disease characterized by the gradual deterioration of cartilage. The involvement of chondrocyte senescence is crucial in the pathogenesis of OA. Desferoxamine (DFO) is an iron chelator with therapeutic potential in various diseases. However, the relationship of chondrocyte senescence and iron homeostasis is largely unknown.

METHODS

Chondrocyte senescence was induced using tert-butyl hydroperoxide (TBHP), and the impact of DFO on chondrocyte senescence and iron metabolism was assessed through techniques such as western blotting, qRT-PCR, and β-Galactosidase staining. To assess the impact of DFO on chondrocyte senescence and the progression of osteoarthritis (OA), the surgical destabilization of the medial meniscus model was established.

RESULTS

In chondrocytes, TBHP administration resulted in elevated expression of P16, P21, and P53, as well as alterations in SA-β-gal staining. Nevertheless, DFO effectively mitigated chondrocyte senescence induced by TBHP, and reversed the decrease in collagen II expression and increase in MMP13 expression caused by TBHP. Mechanismly, TBHP induced NCOA4 expression and iron release in chondrocytes. Excessive iron could induce chondrocyte senescence, whereas, DFO could inhibit NCOA4 expression and restore ferritin level, and chelate excessive iron. Importantly, intra-articular injection of DFO enhanced collagen II expression and reduced expression of P16, P21, and MMP13 of cartilage in OA mice, and delayed cartilage degeneration.

CONCLUSIONS

Overall, this study provides evidence that DFO has the potential to alleviate chondrocyte senescence induced by TBHP and slow down the progression of osteoarthritis (OA) by effectively chelating excessive iron. These findings suggest that iron chelation could be a promising therapeutic strategy for treating OA.

M2 Macrophage-Derived Exosomes Promote Tendon-to-Bone Healing by Alleviating Cellular Senescence in Aged Rats

PURPOSE

To explore the potential of M2 macrophage-derived exosomes (M2-Exos) in enhancing tendon-to-bone healing in aged rats by mitigating cellular senescence of bone marrow-derived stem cells (BMSCs).

METHODS

In vitro, the effects of M2-Exos on alleviating cellular senescence and improving chondrogenic potential of senescent BMSCs were evaluated. Rats (24 young and 48 aged) with chronic rotator cuff tear (RCT) were repaired and assigned into 3 groups: young group (young rats injected with fibrin at the enthesis), aged group (aged rats injected with fibrin at the enthesis), and aged + M2-Exos group (aged rats injected with fibrin containing M2-Exos at the enthesis). At 6 and 12 weeks after repair, enthesis regeneration was evaluated. Proteomic analysis was conducted to explore the mechanism through which M2-Exos mitigated cellular senescence.

RESULTS

In senescent BMSCs treated with M2-Exos, there was a reduction in senescence biomarkers including senescence-associated β-galactosidase, p53, p21, and senescence-associated secretory phenotype (P < .001). M2-Exos also enhanced chondrogenic potential of senescent BMSCs, reflected in greater Bern score (P < .001) and increased expression of Sox9 (P = .013), Col2a1 (P < .001), and Acan (P < .001). Histologically, aged rats treated with M2-Exos demonstrated significantly greater histologic scores (P < .001 at both 6 and 12 weeks) and increased fibrocartilage regeneration at the enthesis. Biomechanically, these rats exhibited greater failure load, stiffness, and stress (all P < .001) at 12 weeks. Mechanistically, proteomic analysis suggested that M2-Exos might alleviate cellular senescence by potentially regulating DNA replication and repair.

CONCLUSIONS

M2-Exos can significantly alleviate BMSC senescence and thereby enhance tendon-to-bone healing in an aged rat RCT model.

CLINICAL RELEVANCE

This study suggests the potential utility of M2-Exos as a therapy for RCT in the older population.

Mechanisms of chondrocyte cell death in osteoarthritis: implications for disease progression and treatment

Osteoarthritis (OA) is a chronic joint disease characterized by the degeneration, destruction, and excessive ossification of articular cartilage. The prevalence of OA is rising annually, concomitant with the aging global population and increasing rates of obesity. This condition imposes a substantial and escalating burden on individual health, healthcare systems, and broader social and economic frameworks. The etiology of OA is multifaceted and not fully understood. Current research suggests that the death of chondrocytes, encompassing mechanisms such as cellular apoptosis, pyroptosis, autophagy, ferroptosis and cuproptosis, contributes to both the initiation and progression of the disease. These cell death pathways not only diminish the population of chondrocytes but also exacerbate joint damage through the induction of inflammation and other deleterious processes. This paper delineates the morphological characteristics associated with various modes of cell death and summarizes current research results on the molecular mechanisms of different cell death patterns in OA. The objective is to review the advancements in understanding chondrocyte cell death in OA, thereby offering novel insights for potential clinical interventions.

10-hydroxy-2-decenoic acid prevents osteoarthritis by targeting aspartyl β hydroxylase and inhibiting chondrocyte senescence in male mice preclinically

Osteoarthritis is a degenerative joint disease with joint pain as the main symptom, caused by fibrosis and loss of articular cartilage. Due to the complexity and heterogeneity of osteoarthritis, there is a lack of effective individualized disease-modifying osteoarthritis drugs in clinical practice. Chondrocyte senescence is reported to participate in occurrence and progression of osteoarthritis. Here we show that small molecule 10-hydroxy-2-decenoic acid suppresses cartilage degeneration and relieves pain in the chondrocytes, cartilage explants from osteoarthritis patients, surgery-induced medial meniscus destabilization or naturally aged male mice. We further confirm that 10-hydroxy-2-decenoic acid exerts a protective effect by targeting the glycosylation site in the Asp_Arg_Hydrox domain of aspartyl β-hydroxylase. Mechanistically, 10-hydroxy-2-decenoic acid alleviate cellular senescence through the ERK/p53/p21 and GSK3β/p16 pathways in the chondrocytes. Our study uncovers that 10-hydroxy-2-decenoic acid modulate cartilage metabolism by targeting aspartyl β-hydroxylase to inhibit chondrocyte senescence in osteoarthritis. 10-hydroxy-2-decenoic acid may be a promising therapeutic drug against osteoarthritis.

Extracellular Vesicle-Contained Thrombospondin 1 Retards Age-Related Degenerative Tendinopathy by Rejuvenating Tendon Stem/Progenitor Cell Senescence

Advanced age is a major risk factor for age-related degenerative tendinopathy. During aging, tendon stem/progenitor cell (TSPC) function declines owing to the transition from a normal quiescent state to a senescent state. Extracellular vesicles (EVs) from young stem cells are reported to possess anti-aging functions. However, it remains unclear whether EVs from young TSPCs (TSPC-EVs) can rejuvenate senescent TSPCs to delay age-related degeneration. Here, this study finds that TSPC-EVs can mitigate the aging phenotypes of senescent TSPCs and maintain their tenogenic capacity. In vitro studies reveal that TSPC-EVs can reinstall autophagy in senescent TSPCs to alleviate cellular senescence, and that the re-establishment of autophagy is mediated by the PI3K/AKT pathway. Mechanistically, this study finds that thrombospondin 1, a negative regulator of the PI3K/AKT pathway, is enriched in TSPC-EVs and can be transported to senescent TSPCs. Moreover, in vivo studies show that the local delivery of TSPC-EVs can rejuvenate senescent TSPCs and promote their tenogenic differentiation, thereby rescuing tendon regeneration in aged rats. Taken together, TSPC-EVs as a novel cell-free approach have promising therapeutic potential for aging-related degenerative tendinopathy.

Mechanisms and applications of the regenerative capacity of platelets-based therapy in knee osteoarthritis

Osteoarthritis (OA) is the most prevalent joint disease in the elderly population and its substantial morbidity and disability impose a heavy economic burden on patients and society. Knee osteoarthritis (KOA) is the most common subtype of OA, which is characterized by damage to progressive articular cartilage, synovitis, and subchondral bone sclerosis. Most current treatments for OA are palliative, primarily aim at symptom management, and do not prevent the progression of the disease or restore degraded cartilage. The activation of α-granules in platelets releases various growth factors that are involved in multiple stages of tissue repair, suggesting potential for disease modification. In recent years, platelet-based therapies, such as platelet-rich plasma, platelet-rich fibrin, and platelet lysates, have emerged as promising regenerative treatments for KOA, but their related effects and mechanisms are still unclear. Therefore, this review aims to summarize the biological characteristics and functions of platelets, classify the products of platelet-based therapy and related preparation methods. Moreover, we summarize the basic research of platelet-based regeneration strategies for KOA and discuss the cellular effects and molecular mechanisms. Further, we describe the general clinical application of platelet-based therapy in the treatment of KOA and the results of the meta-analysis of randomized controlled trials.

Memantine attenuates the development of osteoarthritis by blocking NMDA receptor mediated calcium overload and chondrocyte senescence

Background

Memantine, which is an FDA-proven drug for the treatment of dementia, exerts its function by blocking the function of NMDA (N-methyl-D-aspartate) receptor, a calcium-permeable ion channel that reduces cytotoxic calcium overload. Chondrocyte senescence is a crucial cellular event that contributes to articular cartilage degeneration during osteoarthritis (OA) development. To date, the effects of memantine and its downstream NMDA receptor on chondrocyte senescence and OA have been rarely reported.

Methods

The protein levels of NMDA receptor and its agonistic ligand, glutamate, were compared between normal and OA chondrocytes. The quantity of intracellular calcium ions and the level of mitochondrial damage were evaluated using specific fluorescent probes and transmission electron microscopy (TEM), respectively. Chondrocyte senescence was evaluated by senescence-associated β-galactosidase (SA-β-Gal) staining and p16INK4a analysis. The function of NMDA receptor in chondrocyte senescence and OA was tested via agonists activation and gene knockdown experiments. The therapeutic effects of memantine on OA were examined both in vitro and in vivo. Additionally, to verify the findings from animal samples, a propensity score-matched cohort study was conducted using data from a United Kingdom primary care database (i.e., IQVIA Medical Research Database [IMRD]) to compare the risk of OA-related joint replacement involved in memantine initiators versus active comparators (i.e., acetylcholinesterase [AchE] initiators) in patients with dementia.

Results

The protein expression of NMDA receptor and the secretion of glutamate were both significantly increased in OA chondrocytes. NMDA receptor activation was found to stimulate chondrocyte calcium overload, which further led to mitochondrial fragmentation and chondrocyte senescence. Blocking the NMDA receptor with memantine and N-methyl-D-aspartate receptor subunit 1(NR1, the gene encoding NMDA receptor) knockdown resulted in reduced calcium influx, mitochondrial fragmentation, as well as cellular senescence in OA chondrocytes. Intra-articular injection of memantine in OA mice also exhibited protective effects against cartilage degeneration. Moreover, in the 1:5 propensity score-matched cohort study consisting of 6218 patients (n = 1435 in the memantine cohort; n = 4783 in the AchE cohort), the memantine initiator was associated with a lower risk of OA-related joint replacement than AchE initiators (Hazard ratio = 0.56, 95 % confidence interval: 0.34 to 0.99).

Conclusion

NMDA receptor plays an important role in inflammatory-induced cytotoxic calcium overload in chondrocytes, while memantine can effectively block the NMDA receptor to reduce chondrocyte senescence and retard the development of OA.

The translational potential of this article

As a clinically licensed drug used for the treatment of dementia, memantine has shown promising therapeutic effects on OA. Mechanistically, it functions by blocking NMDA receptor from mediating chondrocyte senescence. The protective effects of memantine against OA were verified not only by in vivo and in vitro experiments but also via a propensity score-matched human cohort study. These findings presented robust evidence for repurposing memantine for the treatment of OA.

Zwitterion-Lubricated Hydrogel Microspheres Encapsulated with Metformin Ameliorate Age-Associated Osteoarthritis

Chondrocyte senescence and reduced lubrication play pivotal roles in the pathogenesis of age-related osteoarthritis (OA). In the present study, highly lubricated and drug-loaded hydrogel microspheres are designed and fabricated through the radical polymerization of sulfobetaine (SB)-modified hyaluronic acid methacrylate using microfluidic technology. The copolymer contains a large number of SB and carboxyl groups that can provide a high degree of lubrication through hydration and form electrostatic loading interactions with metformin (Met@SBHA), producing a high drug load for anti-chondrocyte senescence. Mechanical, tribological, and drug release analyses demonstrated enhanced lubricative properties and prolonged drug dissemination of the Met@SBHA microspheres. RNA sequencing (RNA-seq) analysis, network pharmacology, and in vitro assays revealed the extraordinary capacity of Met@SBHA to combat chondrocyte senescence. Additionally, inducible nitric oxide synthase (iNOS) has been identified as a promising protein modulated by Met in senescent chondrocytes, thereby exerting a significant influence on the iNOS/ONOO-/P53 pathway. Notably, the intra-articular administration of Met@SBHA in aged mice ameliorated cartilage senescence and OA pathogenesis. Based on the findings of this study, Met@SBHA emerges as an innovative and promising strategy in tackling age-related OA serving the dual function of enhancing joint lubrication and mitigating cartilage senescence.

Promoting Articular Cartilage Regeneration through Microenvironmental Regulation

In recent years, as the aging population continues to grow, osteoarthritis (OA) has emerged as a leading cause of disability, with its incidence rising annually. Current treatments of OA include exercise and medications in the early stages and total joint replacement in the late stages. These approaches only relieve pain and reduce inflammation; however, they have significant side effects and high costs. Therefore, there is an urgent need to identify effective treatment methods that can delay the pathological progression of this condition. The changes in the articular cartilage microenvironment, which are complex and diverse, can aggravate the pathological progression into a vicious cycle, inhibiting the repair and regeneration of articular cartilage. Understanding these intricate changes in the microenvironment is crucial for devising effective treatment modalities. By searching relevant research articles and clinical trials in PubMed according to the keywords of articular cartilage, microenvironment, OA, mechanical force, hypoxia, cytokine, and cell senescence. This study first summarizes the factors affecting articular cartilage regeneration, then proposes corresponding treatment strategies, and finally points out the future research direction. We find that regulating the opening of mechanosensitive ion channels, regulating the expression of HIF-1, delivering growth factors, and clearing senescent cells can promote the formation of articular cartilage regeneration microenvironment. This study provides a new idea for the treatment of OA in the future, which can promote the regeneration of articular cartilage through the regulation of the microenvironment so as to achieve the purpose of treating OA.

Mechanism of drug-pairs Astragalus Mongholicus-Largehead Atractylodes on treating knee osteoarthritis investigated by GEO gene chip with network pharmacology and molecular docking

Investigations into the therapeutic potential of Astragalus Mongholicus (AM, huáng qí) and Largehead Atractylodes (LA, bái zhú) reveal significant efficacy in mitigating the onset and progression of knee osteoarthritis (KOA), albeit with an elusive mechanistic understanding. This study delineates the primary bioactive constituents and their molecular targets within the AM-LA synergy by harnessing the comprehensive Traditional Chinese Medicine (TCM) network databases, including TCMSP, TCMID, and ETCM. Furthermore, an analysis of 3 gene expression datasets, sourced from the gene expression omnibus database, facilitated the identification of differential genes associated with KOA. Integrating these findings with data from 5 predominant databases yielded a refined list of KOA-associated targets, which were subsequently aligned with the gene signatures corresponding to AM and LA treatment. Through this alignment, specific molecular targets pertinent to the AM-LA therapeutic axis were elucidated. The construction of a protein-protein interaction network, leveraging the shared genetic markers between KOA pathology and AM-LA intervention, enabled the identification of pivotal molecular targets via the topological analysis facilitated by CytoNCA plugins. Subsequent GO and KEGG enrichment analyses fostered the development of a holistic herbal-ingredient-target network and a core target-signal pathway network. Molecular docking techniques were employed to validate the interaction between 5 central molecular targets and their corresponding active compounds within the AM-LA complex. Our findings suggest that the AM-LA combination modulates key biological processes, including cellular activity, reactive oxygen species modification, metabolic regulation, and the activation of systemic immunity. By either augmenting or attenuating crucial signaling pathways, such as MAPK, calcium, and PI3K/AKT pathways, the AM-LA dyad orchestrates a comprehensive regulatory effect on immune-inflammatory responses, cellular proliferation, differentiation, apoptosis, and antioxidant defenses, offering a novel therapeutic avenue for KOA management. This study, underpinned by gene expression omnibus gene chip analyses and network pharmacology, advances our understanding of the molecular underpinnings governing the inhibitory effects of AM and LA on KOA progression, laying the groundwork for future explorations into the active components and mechanistic pathways of TCM in KOA treatment.

Cellular Senescence and Inflammaging in the Bone: Pathways, Genetics, Anti-Aging Strategies and Interventions

Advancing age is associated with several age-related diseases (ARDs), with musculoskeletal conditions impacting millions of elderly people worldwide. With orthopedic conditions contributing towards considerable number of patients, a deeper understanding of bone aging is the need of the hour. One of the underlying factors of bone aging is cellular senescence and its associated senescence associated secretory phenotype (SASP). SASP comprises of pro-inflammatory markers, cytokines and chemokines that arrest cell growth and development. The accumulation of SASP over several years leads to chronic low-grade inflammation with advancing age, also known as inflammaging. The pathways and molecular mechanisms focused on bone senescence and inflammaging are currently limited but are increasingly being explored. Most of the genes, pathways and mechanisms involved in senescence and inflammaging coincide with those associated with cancer and other ARDs like osteoarthritis (OA). Thus, exploring these pathways using techniques like sequencing, identifying these factors and combatting them with the most suitable approach are crucial for healthy aging and the early detection of ARDs. Several approaches can be used to aid regeneration and reduce senescence in the bone. These may be pharmacological, non-pharmacological and lifestyle interventions. With increasing evidence towards the intricate relationship between aging, senescence, inflammation and ARDs, these approaches may also be used as anti-aging strategies for the aging bone marrow (BM).

Abnormal mechanical stress induced chondrocyte senescence by YAP loss-mediated METTL3 upregulation

OBJECTIVES

Abnormal mechanical stress is the pivotal risk factor of temporomandibular joint osteoarthritis (TMJOA). This study investigated the pathogenic mechanism by which abnormal mechanical stress induced chondrocyte senescence.

MATERIALS AND METHODS

Cellular senescence was investigated in the rodent model of unilateral anterior crossbite and in the chondrocytes subjected to mechanical overloading in vitro. The effects of Yes-associated protein (YAP) in chondrocyte senescence and its correlation with methyltransferase-like 3 (METTL3) and N6-methyladenosine (m6A) modification were evaluated. The role of m6A modification in chondrocyte senescence was determined. The therapeutic effects of m6A inhibition in TMJOA were investigated.

RESULTS

Senescent chondrocytes were accumulated in the mechanically induced TMJOA lesions in rats and mechanical overloading could trigger chondrocyte senescence in vitro. This mechanical stress-induced cellular senescence was revealed to be mediated by YAP deficiency that promoted METTL3-dependent m6A modification. Moreover, inhibition of m6A modification rescued chondrocyte senescence in vitro and in vivo, and suppressed TMJOA progression in rats.

CONCLUSIONS

This study uncovered the underlying mechanism of mechanically induced senescence in TMJOA from the perspective of epitranscriptomics and revealed the therapeutic potential of m6A inhibition in TMJOA.

Targeting the senescence-related genes MAPK12 and FOS to alleviate osteoarthritis

Background

The mechanism by which chondrocyte senescence aggravate OA progression has not yet been well elucidated. The aim of this study was to investigate the chondrocyte senescence related gene biosignatures in OA, and to analyze on the underlying mechanisms of senescence in OA.

Materials and methods

We intersected osteoarthritis dataset GSE82107 from GEO database and senescence dataset from CellAge database of human senescence-associated genes based on genetic manipulations experiments plus gene expression profilin, and screened out 4 overlapping genes. The hub genes were verified in vitro and in human OA cartilage tissues by qRT-PCR. We further confirmed the function of mitogen-activated protein kinase 12 (MAPK12) and Fos proto-oncogene (FOS) in OA in vitro and in vivo by qRT-PCR, western blotting, Edu staining, immunofluorescence, SA-β-gal staining, HE, IHC, von frey test, and hot plate.

Results

1458 downregulated and 218 upregulated DEGs were determined from GSE82107, and 279 human senescence-associated genes were downloaded from CellAge database. After intersection assay, we screened out 4 overlapping genes, of which FOS, CYR61 and TNFSF15 were upregulated, MAPK12 was downregulated. The expression of MAPK12 was obviously downregulated, whereas the expression profiles of FOS, CYR61 and TNFSF15 were remarkedly upregulated in H2O2- or IL-1β-stimulated C28/I2 cells, human OA cartilage tissues, and knee cartilage of aging mice. Furthermore, both MAPK12 over-expression and FOS knock-down can promote cell proliferation and cartilage anabolism, inhibit cell senescence and cartilage catabolism, relieve joint pain in H2O2- or IL-1β-stimulated C28/I2 cells and mouse primary chondrocytes, destabilization of the medial meniscus (DMM) mice.

Conclusion

This study explored that MAPK12 and FOS are involved in the occurrence and development of OA through modulating chondrocyte senescence. They might be biomarkers of OA chondrocyte senescence, and provides some evidence as subsequent possible therapeutic targets for OA.

The translational potential of this article

The translation potential of this article is that we revealed MAPK12 and FOS can effectively alleviate OA by regulating chondrocyte senescence, and thus provided potential therapeutic targets for prevention or treatment of OA in the future.

siRNA therapy in osteoarthritis: targeting cellular pathways for advanced treatment approaches

Osteoarthritis (OA) is a common joint disorder characterized by the degeneration of cartilage and inflammation, affecting millions worldwide. The disease's complex pathogenesis involves various cell types, such as chondrocytes, synovial cells, osteoblasts, and immune cells, contributing to the intricate interplay of factors leading to tissue degradation and pain. RNA interference (RNAi) therapy, particularly through the use of small interfering RNA (siRNA), emerges as a promising avenue for OA treatment due to its capacity for specific gene silencing. siRNA molecules can modulate post-transcriptional gene expression, targeting key pathways involved in cellular proliferation, apoptosis, senescence, autophagy, biomolecule secretion, inflammation, and bone remodeling. This review delves into the mechanisms by which siRNA targets various cell populations within the OA milieu, offering a comprehensive overview of the potential therapeutic benefits and challenges in clinical application. By summarizing the current advancements in siRNA delivery systems and therapeutic targets, we provide a solid theoretical foundation for the future development of novel siRNA-based strategies for OA diagnosis and treatment, paving the way for innovative and more effective approaches to managing this debilitating disease.

Lipids and lipid metabolism in cellular senescence: Emerging targets for age-related diseases

Cellular senescence is a kind of cellular state triggered by endogenous or exogenous stimuli, which is mainly characterized by stable cell cycle arrest and complex senescence-associated secretory phenotype (SASP). Once senescent cells accumulate in tissues, they may eventually accelerate the progression of age-related diseases, such as atherosclerosis, osteoarthritis, chronic lung diseases, cancers, etc. Recent studies have shown that the disorders of lipid metabolism are not only related to age-related diseases, but also regulate the cellular senescence process. Based on existing research evidences, the changes in lipid metabolism in senescent cells are mainly concentrated in the metabolic processes of phospholipids, fatty acids and cholesterol. Obviously, the changes in lipid-metabolizing enzymes and proteins involved in these pathways play a critical role in senescence. However, the link between cellular senescence, changes in lipid metabolism and age-related disease remains to be elucidated. Herein, we summarize the lipid metabolism changes in senescent cells, especially the senescent cells that promote age-related diseases, as well as focusing on the role of lipid-related enzymes or proteins in senescence. Finally, we explore the prospect of lipids in cellular senescence and their potential as drug targets for preventing and delaying age-related diseases.

Kirigami triboelectric spider fibroin microneedle patches for comprehensive joint management

Joint injuries are among the leading causes of disability. Present concentrations were focused on oral drugs and surgical treatment, which brings severe and unnecessary difficulties for patients. Smart patches with high flexibility and intelligent drug control-release capacity are greatly desirable for efficient joint management. Herein, we present a novel kirigami spider fibroin-based microneedle triboelectric nanogenerator (KSM-TENG) patch with distinctive features for comprehensive joint management. The microneedle patch consists of two parts: the superfine tips and the flexible backing base, which endow it with great mechanical strength to penetrate the skin and enough flexibility to fit different bends. Besides, the spider fibroin-based MNs served as a positive triboelectric material to generate electrical stimulation, thereby forcing drug release from needles within 720 min. Especially, kirigami structures could also transform the flat patch into three dimensions, which could impart the patch with flexible properties to accommodate the complicated processes produced by joint motion. Benefiting from these traits, the KSM-TENG patch presents excellent performance in inhibiting the inflammatory response and promoting wound healing in mice models. The results indicated that the mice possessed only 2% wound area and the paw thickness was reduced from 10.5 mm to 6.2 mm after treatment with the KSM-TENG patch, which further demonstrates the therapeutic effect of joints in vivo. Thus, it is believed that the proposed novel KSM-TENG patch is valuable in the field of comprehensive treatments and personalized clinical applications.

MiR-653-5p drives osteoarthritis pathogenesis by modulating chondrocyte senescence

BACKGROUND

Due to the unclear pathogenesis of osteoarthritis (OA), effective treatment for this ailment is presently unavailable. Accumulating evidence points to chondrocyte senescence as a key driver in OA development. This study aims to identify OA-specific microRNAs (miRNAs) targeting chondrocyte senescence to alleviate OA progression.

METHODS

We screened and identified miRNAs differentially expressed in OA and normal cartilage, then confirmed the impact of miR-653-5p on chondrocyte functions and senescence phenotypes through in vitro experiments with overexpression/silencing. We identified interleukin 6 (IL-6) as the target gene of miR-653-5p and confirmed the regulatory influence of miR-653-5p on the IL-6/JAK/STAT3 signaling pathway through gain/loss-of-function studies. Finally, we assessed the therapeutic efficacy of miR-653-5p on OA using a mouse model with destabilization of the medial meniscus.

RESULTS

MiR-653-5p was significantly downregulated in cartilage tissues and chondrocytes from OA patients. Overexpression of miR-653-5p promoted chondrocyte matrix synthesis and proliferation while inhibiting chondrocyte senescence. Furthermore, bioinformatics target prediction and the luciferase reporter assays identified IL-6 as a target of miR-653-5p. Western blot assays demonstrated that miR-653-5p overexpression inhibited the protein expression of IL-6, the phosphorylation of JAK1 and STAT3, and the expression of chondrocyte senescence phenotypes by regulating the IL-6/JAK/STAT3 signaling pathway. More importantly, the cartilage destruction was significantly alleviated and chondrocyte senescence phenotypes were remarkably decreased in the OA mouse model treated by agomiR-653-5p compared to the control mice.

CONCLUSIONS

MiR-653-5p showed a significant decrease in cartilage tissues of individuals with OA, leading to an upregulation of chondrocyte senescence phenotypes in the articular cartilage. AgomiR-653-5p emerges as a potential treatment approach for OA. These findings provide further insight into the role of miR-653-5p in chondrocyte senescence and the pathogenesis of OA.

Matrix stiffening promotes chondrocyte senescence and the osteoarthritis development through downregulating HDAC3

Extracellular matrix (ECM) stiffening is a typical characteristic of cartilage aging, which is a quintessential feature of knee osteoarthritis (KOA). However, little is known about how ECM stiffening affects chondrocytes and other molecules downstream. This study mimicked the physiological and pathological stiffness of human cartilage using polydimethylsiloxane (PDMS) substrates. It demonstrated that epigenetic Parkin regulation by histone deacetylase 3 (HDAC3) represents a new mechanosensitive mechanism by which the stiffness matrix affected chondrocyte physiology. We found that ECM stiffening accelerated cultured chondrocyte senescence in vitro, while the stiffness ECM downregulated HDAC3, prompting Parkin acetylation to activate excessive mitophagy and accelerating chondrocyte senescence and osteoarthritis (OA) in mice. Contrarily, intra-articular injection with an HDAC3-expressing adeno-associated virus restored the young phenotype of the aged chondrocytes stimulated by ECM stiffening and alleviated OA in mice. The findings indicated that changes in the mechanical ECM properties initiated pathogenic mechanotransduction signals, promoted the Parkin acetylation and hyperactivated mitophagy, and damaged chondrocyte health. These results may provide new insights into chondrocyte regulation by the mechanical properties of ECM, suggesting that the modification of the physical ECM properties may be a potential OA treatment strategy.

What improvements do general exercise training and traditional Chinese exercises have on knee osteoarthritis? A narrative review based on biological mechanisms and clinical efficacy

BACKGROUND

Knee osteoarthritis (KOA) is a disease that significantly affects the quality of life of patients, with a complex pathophysiology that includes degeneration of cartilage and subchondral bone, synovitis, and associations with mechanical load, inflammation, metabolic factors, hormonal changes, and aging.

OBJECTIVE

This article aims to comprehensively review the biological mechanisms and clinical effects of general exercise training and traditional Chinese exercises (such as Tai Chi and Qigong) on the treatment of KOA, providing references for the development of clinical exercise prescriptions.

METHODS

A systematic search of databases including PubMed, Web of Science, Google Scholar, and China National Knowledge Infrastructure (CNKI) was conducted, reviewing studies including randomized controlled trials (RCTs), observational studies, systematic reviews, and meta-analyses. Keywords included "knee osteoarthritis," "exercise therapy," "physical activity," and "traditional Chinese exercise."

RESULTS AND CONCLUSION

General exercise training positively affects KOA by mechanisms such as promoting blood circulation, improving the metabolism of inflammatory factors, enhancing the expression of anti-inflammatory cytokines, and reducing cartilage cell aging. Traditional Chinese exercises, like Tai Chi and Qigong, benefit the improvement of KOA symptoms and tissue repair by regulating immune function and alleviating joint inflammation. Clinical studies have shown that both types of exercise can improve physical function, quality of life, and pain relief in patients with KOA. Both general exercise training and traditional Chinese exercises are non-pharmacological treatment options for KOA that can effectively improve patients' physiological function and quality of life. Future research should further explore the long-term effects and biological mechanisms of these exercise interventions and develop personalized exercise programs based on the specific needs of patients.

In Situ Remodeling of Efferocytosis via Lesion-Localized Microspheres to Reverse Cartilage Senescence

Efferocytosis, an intrinsic regulatory mechanism to eliminate apoptotic cells, will be suppressed due to the delayed apoptosis process in aging-related diseases, such as osteoarthritis (OA). In this study, cartilage lesion-localized hydrogel microspheres are developed to remodel the in situ efferocytosis to reverse cartilage senescence and recruit endogenous stem cells to accelerate cartilage repair. Specifically, aldehyde- and methacrylic anhydride (MA)-modified hyaluronic acid hydrogel microspheres (AHM), loaded with pro-apoptotic liposomes (liposomes encapsulating ABT263, A-Lipo) and PDGF-BB, namely A-Lipo/PAHM, are prepared by microfluidic and photo-cross-linking techniques. By a degraded porcine cartilage explant OA model, the in situ cartilage lesion location experiment illustrated that aldehyde-functionalized microspheres promote affinity for degraded cartilage. In vitro data showed that A-Lipo induced apoptosis of senescent chondrocytes (Sn-chondrocytes), which can then be phagocytosed by the efferocytosis of macrophages, and remodeling efferocytosis facilitated the protection of normal chondrocytes and maintained the chondrogenic differentiation capacity of MSCs. In vivo experiments confirmed that hydrogel microspheres localized to cartilage lesion reversed cartilage senescence and promoted cartilage repair in OA. It is believed this in situ efferocytosis remodeling strategy can be of great significance for tissue regeneration in aging-related diseases.

Osteoclasts and osteoarthritis: Novel intervention targets and therapeutic potentials during aging

Osteoarthritis (OA), a chronic degenerative joint disease, is highly prevalent among the aging population, and often leads to joint pain, disability, and a diminished quality of life. Although considerable research has been conducted, the precise molecular mechanisms propelling OA pathogenesis continue to be elusive, thereby impeding the development of effective therapeutics. Notably, recent studies have revealed subchondral bone lesions precede cartilage degeneration in the early stage of OA. This development is marked by escalated osteoclast-mediated bone resorption, subsequent imbalances in bone metabolism, accelerated bone turnover, and a decrease in bone volume, thereby contributing significantly to the pathological changes. While the role of aging hallmarks in OA has been extensively elucidated from the perspective of chondrocytes, their connection with osteoclasts is not yet fully understood. There is compelling evidence to suggest that age-related abnormalities such as epigenetic alterations, proteostasis network disruption, cellular senescence, and mitochondrial dysfunction, can stimulate osteoclast activity. This review intends to systematically discuss how aging hallmarks contribute to OA pathogenesis, placing particular emphasis on the age-induced shifts in osteoclast activity. It also aims to stimulate future studies probing into the pathological mechanisms and therapeutic approaches targeting osteoclasts in OA during aging.

Senolytic therapeutics: An emerging treatment modality for osteoarthritis

Osteoarthritis (OA), a chronic joint disease affecting millions of people aged over 65 years, is the main musculoskeletal cause of diminished joint mobility in the elderly. It is characterized by lingering pain and increasing deterioration of articular cartilage. Aging and accumulation of senescent cells (SCs) in the joints are frequently associated with OA. Apoptosis resistance; irreversible cell cycle arrest; increased p16INK4a expression, secretion of senescence-associated secretory phenotype factors, senescence-associated β-galactosidase levels, secretion of extracellular vesicles, and levels of reactive oxygen and reactive nitrogen species; and mitochondrial dysregulation are some common changes in cellular senescence in joint tissues. Development of OA correlates with an increase in the density of SCs in joint tissues. Senescence-associated secretory phenotype has been linked to OA and cartilage breakdown. Senolytics and therapeutic pharmaceuticals are being focused upon for OA management. SCs can be selectively eliminated or killed by senolytics to halt the pathogenesis and progression of OA. Comprehensive understanding of how aging affects joint dysfunction will benefit OA patients. Here, we discuss age-related mechanisms associated with OA pathogenesis and senolytics as an emerging modality in the management of age-related SCs and pathogenesis of OA in preclinical and clinical studies.

Lei's formula attenuates osteoarthritis mediated by suppression of chondrocyte senescence via the mTOR axis: in vitro and in vivo experiments

Lei's formula (LSF), a traditional Chinese herbal remedy, is recognized for its remarkable clinical effectiveness in treating osteoarthritis (OA). Despite its therapeutic potential, the exact molecular mechanisms underlying LSF's action in OA have remained enigmatic. Existing research has shed light on the role of the mTOR signaling pathway in promoting chondrocyte senescence, a central factor in OA-related cartilage degeneration. Consequently, targeting mTOR to mitigate chondrocyte senescence presents a promising avenue for OA treatment. The primary objective of this study is to establish LSF's chondroprotective potential and confirm its anti-osteoarthritic efficacy through mTOR inhibition. In vivo assessments using an OA mouse model reveal substantial articular cartilage degeneration. However, LSF serves as an effective guardian of articular cartilage, evidenced by reduced subchondral osteosclerosis, increased cartilage thickness, improved surface smoothness, decreased OARSI scores, elevated expression of cartilage anabolic markers (Col2 and Aggrecan), reduced expression of catabolic markers (Adamts5 and MMP13), increased expression of the chondrocyte hypertrophy marker (Col10), and decreased expression of chondrocyte senescence markers (P16 and P21). In vitro findings demonstrate that LSF shields chondrocytes from H2O2-induced apoptosis, inhibits senescence, enhances chondrocyte differentiation, promotes the synthesis of type II collagen and proteoglycans, and reduces cartilage degradation. Mechanistically, LSF suppresses chondrocyte senescence through the mTOR axis, orchestrating the equilibrium between chondrocyte anabolism and catabolism, ultimately leading to reduced apoptosis and decelerated OA cartilage degradation. LSF holds significant promise as a therapeutic approach for OA treatment, offering new insights into potential treatments for this prevalent age-related condition.

Articular cartilage repair biomaterials: strategies and applications

Articular cartilage injury is a frequent worldwide disease, while effective treatment is urgently needed. Due to lack of blood vessels and nerves, the ability of cartilage to self-repair is limited. Despite the availability of various clinical treatments, unfavorable prognoses and complications remain prevalent. However, the advent of tissue engineering and regenerative medicine has generated considerable interests in using biomaterials for articular cartilage repair. Nevertheless, there remains a notable scarcity of comprehensive reviews that provide an in-depth exploration of the various strategies and applications. Herein, we present an overview of the primary biomaterials and bioactive substances from the tissue engineering perspective to repair articular cartilage. The strategies include regeneration, substitution, and immunization. We comprehensively delineate the influence of mechanically supportive scaffolds on cellular behavior, shedding light on emerging scaffold technologies, including stimuli-responsive smart scaffolds, 3D-printed scaffolds, and cartilage bionic scaffolds. Biologically active substances, including bioactive factors, stem cells, extracellular vesicles (EVs), and cartilage organoids, are elucidated for their roles in regulating the activity of chondrocytes. Furthermore, the composite bioactive scaffolds produced industrially to put into clinical use, are also explicitly presented. This review offers innovative solutions for treating articular cartilage ailments and emphasizes the potential of biomaterials for articular cartilage repair in clinical translation.

Therapeutic targets and potential delivery systems of melatonin in osteoarthritis

Osteoarthritis (OA) is a highly prevalent age-related musculoskeletal disorder that typically results in chronic pain and disability. OA is a multifactorial disease, with increased oxidative stress, dysregulated inflammatory response, and impaired matrix metabolism contributing to its onset and progression. The neurohormone melatonin, primarily synthesized by the pineal gland, has emerged as a promising therapeutic agent for OA due to its potential to alleviate inflammation, oxidative stress, and chondrocyte death with minimal adverse effects. The present review provides a comprehensive summary of the current understanding regarding melatonin as a promising pharmaceutical agent for the treatment of OA, along with an exploration of various delivery systems that can be utilized for melatonin administration. These findings may provide novel therapeutic strategies and targets for inhibiting the advancement of OA.

Macrophage migration inhibitory factor reversed senescent phenotype in human chondrocytes in vitro

BACKGROUND

The senescence of chondrocytes, which is closely linked to the development of osteoarthritis (OA), has been found to be influenced by the inflammatory environment of joint cavity. However, there remains a lack of comprehensive understanding regarding the specific mechanisms through which cytokine impacts chondrocytes senescence.

PURPOSE

To investigate the effects of MIF on the chondrocytes senescence and explore the underlying mechanism.

METHODS

Human cytokine array and ELISA were used for the level of MIF in synovium fluid. CCK-8 was used for chondrocytes viability. IF, WB, SA-β-gal staining and flow cytometry were used for the chondrogenic, apoptotic and senescent phenotype of chondrocytes.

RESULTS

The level of MIF was significantly increased in OA patients. MIF significantly reversed the senescent phenotype induced by LPS pretreatment in human chondrocytes. MIF significantly enhanced the expression of Col II, SOX9, and ACAN in LPS pre-treated human chondrocytes. Furthermore, MIF significantly inhibited the apoptosis of LPS-induced senescent chondrocytes.

CONCLUSION

Increased level of MIF in osteoarthritic joint cavity might effectively suppress the senescent phenotype and simultaneously improve the chondrogenic phenotype in chondrocytes, the underlying mechanism was likely to be independent of apoptosis.

A narrative review on inflammaging and late-onset hypogonadism

The increasing life expectancy observed in recent years has resulted in a higher prevalence of late-onset hypogonadism (LOH) in older men. LOH is characterized by the decline in testosterone levels and can have significant impacts on physical and mental health. While the underlying causes of LOH are not fully understood, there is a growing interest in exploring the role of inflammaging in its development. Inflammaging is a concept that describes the chronic, low-grade, systemic inflammation that occurs as a result of aging. This inflammatory state has been implicated in the development of various age-related diseases. Several cellular and molecular mechanisms have been identified as contributors to inflammaging, including immune senescence, cellular senescence, autophagy defects, and mitochondrial dysfunction. Despite the extensive research on inflammaging, its relationship with LOH has not yet been thoroughly reviewed in the literature. To address this gap, we aim to review the latest findings related to inflammaging and its impact on the development of LOH. Additionally, we will explore interventions that target inflammaging as potential treatments for LOH.

Regional disparities, age-related changes and sex-related differences in knee osteoarthritis

BACKGROUND

The objective of the study is to analyse the regions, age and sex differences in the incidence of knee osteoarthritis (KOA).

METHODS

Data were extracted from the global burden of diseases (GBD) 2019 study, including incidence, years lived with disability (YLD), disability-adjusted life-years (DALYs) and risk factors. Estimated annual percentage changes (EAPCs) were calculated to quantify the temporal trends in age standardized rate (ASR) of KOA. Paired t-test, paired Wilcoxon signed-rank test and spearman correlation were performed to analyze the association of sex disparity in KOA and socio-demographic index (SDI).

RESULTS

There were significant regional differences in the incidence of knee osteoarthritis. In 2019, South Korea had the highest incidence of knee osteoarthritis (474.85,95%UI:413.34-539.64) and Thailand had the highest increase in incidence of knee osteoarthritis (EAPC = 0.56, 95%CI = 0.54-0.58). Notably, higher incidence, YLD and DALYs of knee osteoarthritis were associated with areas with a high socio-demographic index (r = 0.336, p < 0.001; r = 0.324, p < 0.001; r = 0.324, p < 0.001). In terms of age differences, the greatest increase in the incidence of knee osteoarthritis was between the 35-39 and 40-44 age groups. (EAPC = 0.52, 95%CI = 0.40-0.63; 0.47, 95%CI = 0.36-0.58). In addition, there were significant sex differences in the disease burden of knee osteoarthritis (P < 0.001).

CONCLUSIONS

The incidence of knee osteoarthritis is significantly different with regions, age and sex.

Identification of aging-related genes in diagnosing osteoarthritis via integrating bioinformatics analysis and machine learning

BACKGROUND

Osteoarthritis (OA) is one of the main causes of pain and disability in the world, it may be caused by many factors. Aging plays a significant role in the onset and progression of OA. However, the mechanisms underlying it remain unknown. Our research aimed to uncover the role of aging-related genes in the progression of OA.

METHODS

In Human OA datasets and aging-related genes were obtained from the GEO database and the HAGR website, respectively. Bioinformatics methods including Gene Ontology (GO), Kyoto Encyclopedia of Genes Genomes (KEGG) pathway enrichment, and Protein-protein interaction (PPI) network analysis were used to analyze differentially expressed aging-related genes (DEARGs) in the normal control group and the OA group. And then weighted gene coexpression network analysis (WGCNA), the least absolute shrinkage and selection operator (LASSO) regression, and the Random Forest (RF) machine learning algorithms were used to find the hub genes.

RESULTS

Four overlapping hub genes: HMGB2, CDKN1A, JUN, and DDIT3 were identified. According to the nomogram model and receiver operating characteristic (ROC) curve analysis, four hub DEARGs had good diagnostic value in distinguishing normal from OA. Furthermore, the qRT-PCR test demonstrated that HMGB2, CDKN1A, JUN, and DDIT3 mRNA expression levels were lower in OA group than in normal group.

CONCLUSION

Finally, these four-hub aging-related genes may help us understand the underlying mechanism of aging in osteoarthritis and could be used as possible diagnostic and therapeutic targets.

Exploration and breakthrough in the mode of chondrocyte death - A potential new mechanism for osteoarthritis

Osteoarthritis (OA) is a frequent chronic joint disease in orthopedics that effects individuals and society significantly. Obesity, aging, genetic susceptibility, and joint misalignment are all known risk factors for OA, but its pathomechanism is still poorly understood. Researches have revealed that OA is a much complex process related to inflammation, metabolic and chondrocyte death. It can affect all parts of the joint and is characterized by causing chondrocyte death and extracellular matrix descent. Previously, OA was thought to develop from excessive mechanical loading leading to the destruction of articular cartilage. Since some programmed cell deaths and OA share a pattern of chondrocyte destruction, it is likely that OA also involves programmed cell death. Even though chondrocyte apoptosis and pyroptosis have been investigated in OA, clarifing solely conventional cell death pathways is still insufficient to understand the pathophysiology of osteoarthritis. With more researches, it has been discovered that osteoarthritis and other new cell death processes, including PANoptosis, ferroptosis, and cell senescence, are strongly associated. Among these, PANoptosis combines the key traits of pyroptosis, cell apoptosis, and necrotic apoptosis into a highly coordinated and dynamically balanced programmed inflammatory cell death mechanism. Furthermore, we think that PANopotosis might obstruct necroptosis and cell senescence. Therefore, in order to offer direction for therapeutic treatment, we evaluate the development of research on multiple cell death of chondrocytes in OA.

Effects of externally-applied, non-pharmacological Interventions on short- and long-term symptoms and inflammatory cytokine levels in patients with knee osteoarthritis: a systematic review and network meta-analysis

Background

With the continuous development of clinical medicine, an increasing number of non-pharmacological interventions have been applied for the treatment of knee osteoarthritis (KOA), with the results of several recent randomized controlled trials (RCTs) showing that a variety of externally-applied, non-pharmacological interventions (EANPI) can improve symptoms and inflammation in patients with KOA. However, the relative benefits and disadvantages of non-drug therapies remain uncertain, and an optimal treatment strategy has not yet been determined.

Objective

This study applied network meta-analysis (NMA) to compare and rank the effectiveness of EANPI on the short- and long-term clinical symptoms and inflammatory cytokine levels in patients with KOA.

Methods

Two independent researchers searched online databases and performed manual retrieval of related citations to identify RCTs that met the selection criteria for the network meta-analysis. These researchers retrieved studies indexed from database inception to August 2023 and performed data extraction and assessment of the risk of bias.

Results

The analysis included 80 RCTs involving 8440 participants and nine externally-applied, non-pharmacological therapies, namely extracorporeal shock wave, radiofrequency, acupotomy, laser therapy, Tuina therapy, kinesio taping, electroacupuncture, platelet-rich plasma injection, and ozone therapy. The treatment courses ranged from 1 to 12 weeks, with follow-up periods ranging from 4 to 24 weeks. The results of the NMA indicated that each non-drug therapy was superior to sham intervention in improving all outcome indicators. Except for the visual analog scale (VAS) and Western Ontario MacMaster (WOMAC) pain outcomes, all non-drug therapies had better efficacy than pharmacological treatments. For short-term VAS and tumor necrosis factor-alpha (TNF-α), extracorporeal shock wave performed better than other therapies (90.2% and 85.2% respectively). Radiofrequency therapy may be the most promising method to reduce long-term VAS, short- and long-term WOMAC pain, and interleukin (IL)-1β level (84.8%, 97.8%, 90.1%, 94.8% respectively). Tuina therapy may be a significant choice for short- and long-term outcomes of WOMAC function and range of motion (ROM).

Conclusions

The results of the comprehensive comparison of the outcome indicators in 9 different EANPI indicated that radiofrequency and Tuina therapy were more effective and consistently ranked high in improving clinical symptoms in the short and long term. Radiofrequency is effective at relieving pain, and Tuina therapy can be given priority for treatment when hypofunction is the main symptom. EANPI to improve pain symptoms may be related to the regulation of inflammatory cytokine levels, which may be a potential mechanism of action.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?, identifier CRD42023464177.