Role of proinflammatory cytokines in the pathophysiology of osteoarthritis. Nat Rev Rheumatol. 2011;7:33-42. [PMID: 21119608 DOI: 10.1038/nrrheum.2010.196]

Single-cell profiling uncovers synovial fibroblast subpopulations associated with chondrocyte injury in osteoarthritis

Background

Chondrocytes and synovial cells participate in the pathogenesis of osteoarthritis (OA). Nonetheless, the interactions and correlations between OA synovial cells and chondrocytes remain unclear. This study aims to elucidate the interactions and correlations between OA synovial cells and chondrocytes, so as to deepen understanding of OA pathogenesis.

Methods

Single-cell sequencing analysis was employed to analyze clusters of synovial and chondrocyte cells within the OA dataset. Through cell interaction analysis, the potential interactions between these two cell types were further explored. Differential gene expression analysis was used to examine the differences among synovial-related cell clusters.

Results

The study identified specific characteristics of synovial fibroblasts through single-cell sequencing analysis. Subsequent cell interaction analysis revealed interactions and correlations between synovial fibroblast clusters and cell clusters in both damaged and non-damaged cartilages. CILP+ fibroblasts showed significant interactions with non-damaged chondrocytes, while POSTN+ fibroblasts exhibited significant interactions with damaged chondrocytes. Furthermore, differential gene expression analysis revealed that genes such as PRELP, CLU, COMP, TNFRSF12A, INHBA, CILP, and SERPINE2, were significantly upregulated in CILP+ fibroblasts. These genes are involved in promoting cell proliferation, inhibiting inflammatory pathways, and stabilizing cell structure, thereby exerting reparative and protective effects on chondrocytes. In contrast, COL6A3, COL6A1, COL1A2, COL1A1, COL3A1, TGF-β1, MMP2, AEBP1, SPARC, FNDC1, and POSTN were upregulated in POSTN+ fibroblasts. These genes may contribute to chondrocyte damage and further degeneration by promoting chondrocyte catabolism, driving inflammation, activating inflammatory pathways, and facilitating chondrocyte apoptosis and destruction.

Conclusion

Our study elucidated the interactions and correlations between OA synovial cells and chondrocytes. CILP+ synovial fibroblasts may exert reparative and protective effects on chondrocytes of patients with OA by promoting cell proliferation, inhibiting inflammation, and stabilizing cellular structures, thereby potentially mitigating the progression of cartilage lesions in affected patients. In contrast, POSTN+ synovial fibroblasts may exacerbate chondrocyte deterioration in patients with OA by enhancing degradation, inflammation, and apoptosis, thereby exacerbating cartilage lesions. Investigating the underlying molecular mechanisms between OA synovial cells and chondrocytes refines the understanding of OA pathogenesis and provides valuable insights for the clinical diagnosis and treatment of OA.

Exploring the Efficacy of Joint Lavage in Knee Osteoarthritis: A Focus on Cytokines, Degrading Enzymes, and Oxidative Stress

PURPOSE/AIM

This study aimed to assess the effectiveness of joint lavage in managing knee osteoarthritis (OA) by evaluating its effect on pain relief, inflammatory markers, cartilage-degrading enzymes, and oxidative stress.

METHODS

Seventy patients with Kellgren-Lawrence grade 2 or 3 knee OA were selected for this single-center study. Joint lavage was performed, and pain and function were measured using the visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at baseline and 24 weeks postintervention. Synovial fluid samples were collected at baseline, before lavage, and 24 weeks postintervention. Samples were stored at -80°C and analyzed in batches to minimize variability. At the time of analysis, the samples were thawed and evaluated for levels of proinflammatory cytokines, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), matrix metalloproteinase-3 (MMP-3), and total oxidant status (TOS), and oxidative stress index (OSI).

RESULTS

Postintervention, VAS, and WOMAC scores significantly decreased (P < 0.001), with 100% achieving the minimal clinically important difference (MCID). Patient acceptable symptom state (PASS) rates varied: VAS (80%), WOMAC pain (50%), function (81.4%), and total (84.3%). Cytokine levels (IL-1β, IL-6, TNF-α) and MMP-3 significantly decreased (P < 0.001), along with TOS and OSI. Baseline TNF-α, IL-6, and IL-1β levels were significantly correlated with improvements in VAS and WOMAC scores. Moderate correlations were observed between reductions in IL-6/TNF-α and improvements in VAS/WOMAC. No significant associations were found between confounders and outcomes.

CONCLUSIONS

Joint lavage resulted in marked pain relief and functional improvement while significantly reducing inflammatory markers, cartilage-degrading enzymes, and oxidative stress.

Nuciferine ameliorates osteoarthritis: An in vitro and in vivo study

Osteoarthritis (OA) is the most common musculoskeletal disease and a leading cause of pain and disability. A key hallmark of OA is cartilage degradation, which occurs due to an imbalance between the synthesis and degradation of the extracellular matrix (ECM). Interleukin-1β(IL-1β) has been reported to regulate ECM metabolism. Nuciferine (Nuc), a natural peptide extracted from the lotus leaf, possesses several significant pharmacological properties. However, the anti-inflammation of Nuc in OA has not been reported. In this study, ELISA and Western blot analyses were used to measure the production of inflammatory mediators in IL-1β-Induced mouse chondrocytes. Additionally, mice with or without surgical destabilization of the medial meniscus (DMM) were treated with intra-articular injection of Nuc. We found that Nuc significantly reduces the level of iNOS, PEG2, and IL-6 in IL-1β-induced chondrocytes. Furthermore, Nuc can ameliorate the development of OA in mice. Mechanistically, we found that the chondrocyte-protective effects of Nuc occur via the PTEN/NF-κB pathway. These findings suggest that Nuc could be a potential therapeutic agent for improving OA development.

Kongensin A targeting PI3K attenuates inflammation-induced osteoarthritis by modulating macrophage polarization and alleviating inflammatory signaling

The inflammatory microenvironment, polarization of macrophages towards the M1 phenotype, and consequent matrix degradation and senescence of chondrocytes are primary contributors to the degeneration of knee joint cartilage, further exacerbating the progression of osteoarthritis (OA). Kongensin A (KA) is a recently identified natural plant extract exhibiting anti-necrotic apoptosis and anti-inflammatory properties, but the potential efficacy in alleviating OA remains uncertain. The current research lucubrated the effect of KA on the inflammatory microenvironment and macrophage polarization, as well as its regulatory function in extracellular matrix (ECM) metabolism and chondrocyte senescence. Our findings demonstrated that KA can suppress inflammatory signaling, maintain homeostasis between ECM anabolism and catabolism, and suppress chondrocytes senescence. Further investigation elucidated that the mechanism involves the suppression of the PI3K/AKT/NF-κB axis in chondrocytes under inflammatory conditions. Moreover, KA impeded M1 polarization of macrophages via inhibiting PI3K/AKT/NF-κB axis. Subsequently, we treated chondrocytes with macrophages-derived conditioned medium (CM) and revealed that KA can promote ECM anabolism and alleviate chondrocytes senescence by reprogramming macrophage polarization. Consistent with in vitro experiments, in vivo administration of KA demonstrated alleviated cartilage degeneration and delayed progression of OA. Collectively, through obstructing the PI3K/AKT/NF-κB axis, KA can reprogram macrophage polarization, promote matrix metabolism equilibrium, and alleviate chondrocytes senescence, thereby attenuating the pathology of OA. In conclusion, KA may emerge as a promising therapy for OA.

Comparison of Early-Stage Knee Osteoarthritis Induced by Medial Meniscus Tear Versus Tibial Osteotomy in the Rat Model

OBJECTIVE

Medial meniscus tear (MMT) is a common method to induce osteoarthritis in rats, but mimics secondary osteoarthritis. A novel method of carrying out a medial wedge closing tibial osteotomy (TO) has been recently developed to induce primary osteoarthritis. This study aims to validate it, compared to MMT.

METHODS

Twenty rats were divided equally into 2 groups. Outcome measures such as histology graded according to Osteoarthritis Research Society International (OARSI) guidelines and computed tomography (CT) scans were analyzed at 6 weeks post-operatively. Observational gait analysis and serum biomarkers such as C-terminal cross-linked telopeptides of type II collagen (CTX-II) and interleukin-1 beta (IL-1β) were collected at 2-weekly intervals up to 6 weeks post-operatively.

RESULTS

Serum CTX-II and IL-1β levels did not reveal a statistically significant difference across all time points between the 2 groups. CT grading was significantly more severe (2.80 ± 1.10 vs 1.40 ± 0.548, P = 0.0389) in the MMT group compared to the TO group. In addition, histological gradings such as calcified cartilage score (2.10 ± 1.91 vs 0.00 ± 0.00, P < 0.01) and cartilage degeneration score (4.80 ± 5.18 vs 0.00 ± 0.00, P < 0.01) revealed significantly more severe osteoarthritis in the MMT compared to TO group. Synovial membrane score did not reveal a statistically significant difference (1.10 ± 0.994 vs 1.00 ± 0.00, P = 1.00).

CONCLUSION

TO is a novel method in inducing primary osteoarthritis in the rat model compared to MMT between the 6 and 12 weeks' time frame.

Exploring the role of ATF3 and ferroptosis-related RNA expression in osteoarthritis: An RNA analysis approach to immune infiltration

Osteoarthritis (OA) is a widespread joint disorder that is primarily noted for the progressive degeneration of joint cartilage, accompanied by a significant inflammatory response. Recently, there has been a growing interest in understanding the roles of ATF3 and ferritin-related RNAs in the context of immune responses and inflammatory processes. However, their specific functions and mechanisms in the progression of osteoarthritis have remained largely ambiguous and underexplored. The primary objective of this study was to thoroughly investigate the changes in expression levels of ATF3 and ferritin-related RNAs within osteoarthritic tissues, as well as to examine their potential effects on immune cell infiltration. To achieve this, advanced RNA sequencing technology was employed to meticulously analyze the expression levels of ATF3 and the ferritin-related RNAs. Furthermore, bioinformatics methods were utilized to assess the infiltration patterns of various immune cells and to explore the correlation between these infiltration patterns and the expression levels of RNA. The findings from this study revealed that both ATF3 and ferritin-related RNAs exhibited significantly elevated expression levels in tissues affected by osteoarthritis. Additionally, the immunoinfiltration analysis highlighted a positive correlation between the degree of infiltration of T cells and macrophages and the levels of ferritin-related RNAs. Such findings suggest that the presence of these immune cells is intricately linked to the expression of ferritin-associated RNAs. Further investigations indicated that ferritin-associated RNAs play a critical role in the progression of osteoarthritis by modulating inflammatory responses and influencing the activity of various immune cells. Consequently, both ATF3 and ferritin-related RNAs demonstrate abnormal expression patterns in osteoarthritis, which are closely associated with the infiltration of immune cells.

Effects of Bacillus coagulans on kidney injury caused by Klebsiella pneumoniae in rabbits

Klebsiella pneumoniae (KP) is a zoonotic conditionally pathogenic bacterium with a high prevalence of infection. It often induces purulent inflammation of the rabbit lungs, kidneys and other tissues, with high morbidity and mortality. Bacillus coagulans (BC) has the ability to regulate the balance of host intestinal flora and improve host immunity. However, the mechanism of the protective effect of BC on KP-induced kidney injury in rabbits is not clear. To explore this, we randomly divided fifty 35-day-old Eyplus rabbits into five groups: control, KP, low-dose BC (LBC), medium-dose BC (MBC) and high-dose BC (HBC). On the 1st day of the experiment, rabbits in LBC, MBC and HBC groups were fed diets containing 1 × 106 CFU/g, 5 × 106 CFU/g and 1 × 107 CFU/g BC, respectively, and rabbits in CK and KP groups were fed basal diets. On the 8th day, each rabbit in the KP, LBC, MBC and HBC groups was infused with 4 mL of 1 × 1011 CFU/mL KP bacterial solution, and the CK group was infused with the same amount of sterilised saline for a total of 7 days. Rabbit kidney tissues were collected on the 15th d. HE staining was used to observe the pathological changes of rabbit kidney tissues, oxidative stress-related indexes were detected by biochemical kits, and the content of inflammatory factors and apoptosis-related factors in kidney tissues were detected by ELISA. The results showed that KP disrupts the normal structure of the kidney, induces oxidative stress and inflammatory responses, and mediates apoptosis by regulating the levels of Bcl-2 family proteins. BC pretreatment significantly reduced kidney structural damage, oxidative stress, inflammatory response, and apoptosis in rabbits. To alleviate KP-induced kidney injury by increasing the activity of antioxidant enzymes and the content of anti-apoptotic proteins. Compared with the LBC group and the HBC group, the remission effect was more pronounced in the MBC group. Therefore, in this study, the effect of 5 × 106 CFU/g BC was more significant.

Gelatin microcarriers as an effective adipose-derived stem cells delivery strategy in osteoarthritis treatment

Despite their clinical success, stem cells (SCs) in the treatment of osteoarthritis (OA) are limited by lower retention efficiency and restricted paracrine function. The development of effective SCs culture and delivery systems to maintain or promote SCs paracrine function is urgently needed. In this study, we focused on gelatin microcarriers with different sizes as SCs culture scaffold for OA therapy. The effect of culturing adipose-derived stem cells (ADSCs) on different size microcarriers (180 μm and 320 μm) to promote paracrine function was evaluated. The secretome of ADSCs cultured on microcarriers more effectively regulated macrophages and chondrocytes in a direction favorable to OA healing compared to culture plates. In particular, microcarriers with ADSCs effectively reduced the coefficient of friction at the cartilage interface. Injection low-dose ADSCs without and with different size microcarriers into the knee joints in rats' OA model was achieved. Even better OA therapeutic effects were achieved by using smaller size (higher curvature) microcarriers to deliver ADSCs at low doses. Microcarrier-based cell delivery strategies offer potential solution method for OA therapy.

MSCs-derived ECM functionalized hydrogel regulates macrophage reprogramming for osteoarthritis treatment by improving mitochondrial function and energy metabolism

Osteoarthritis (OA) is a degenerative disease that affects the entire joint, with synovial inflammation being a major pathological feature. Macrophages, as the most abundant immune cells in the synovium, have an M1/M2 imbalance that is closely related to the occurrence and development of OA. Mesenchymal stem cells (MSCs) have been shown to effectively suppress inflammation in the treatment of OA, but they still pose issues such as immune rejection and tumorigenicity. The extracellular matrix (ECM), as a major mediator of MSCs' immunoregulatory effects, offers a cell-free therapy to circumvent these risks. In this study, we developed an ECM-functionalized hydrogel by combining MSC-derived ECM with gelatin methacryloyl (GelMA). To enhance the immunomodulatory potential of MSCs, we pre-stimulated MSCs with the inflammatory factor interleukin-6 (IL-6) present in OA. In vitro results showed that the ECM-functionalized hydrogel promoted M2 macrophage polarization and inhibited the expression of various inflammatory genes, strongly indicating the hydrogel's powerful immunoregulatory capabilities. In an in vivo rat OA model, the ECM-functionalized hydrogel significantly reduced synovial inflammation and cartilage matrix degradation, alleviating the progression of OA. Furthermore, we utilized proteomics and transcriptomics analysis to reveal that the hydrogel accomplished macrophage metabolic reprogramming by regulating mitochondrial function and energy metabolism, thereby reducing inflammation. These findings suggest that the ECM-functionalized hydrogel is a promising biomaterial-based strategy for treating OA by targeting key pathological mechanisms.

Inflammatory markers in early knee joint osteoarthritis differ from well-matched controls and are associated with consistent, rather than intermittent knee pain

BACKGROUND

Osteoarthritis (OA) is characterised by the failure of normal biological processes to repair following damage. Traditionally, OA was considered a "wear and tear" disorder; however, it is now a recognised inflammatory condition, preceded by molecular modifications. The aim of this study was to evaluate inflammatory markers among individuals with early knee OA (eKOA) and well-matched asymptomatic controls.

METHODS

Twenty six eKOA (females, n = 13; age = 60.2 ± 5.4 yrs, height = 1.73 ± 0.11 m, body mass = 77.8 ± 12.8 kg, body fat = 33.9 ± 8.5%) and twenty-three asymptomatic individuals (females, n = 14; age = 59.9 ± 5.5yrs, height = 1.71 ± 0.09 m, body mass = 72.6 ± 11.3 kg, body fat = 30.4 ± 8.2%) were recruited. The Timed Up and Go, and the 6 Minute Walk Tests evaluated physical function in addition to pain specific questionnaires (KOOS and ICOAP). Serum levels of IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8(CXCL8), IL-10, hsCRP and TNF-α were quantified using a multiplex assay via V-plex®Sector Imager 2400.

RESULTS

As hypothesised, only KOOS and EQ-5D-5L metrics differed between the groups for non-blood derived measures (p < 0.04). Only IL-6 was higher in eKOA (P = 0.02; 95% CI = 0.202; by 0.197 pg/mL; 34.5%). Among eKOA, IL-6 did not relate to severity of KOOS pain (P = 0.696, r = -0.088), but had a positive relationship with ICOAP consistent (r = 0.469, P = 0.045) rather than intermittent pain. There was a moderate correlation between 6MWD and IL-8 (r = 0.471, P = 0.012).

CONCLUSION

Our results illustrate the potential for IL-6 as a biomarker for eKOA, and introduce the proposition for particular consideration in those with consistent pain. Further, for the first time the present data showed greater walking distance in eKOA with lower circulating IL-8. Future work should seek to verify these results and further investigate IL-6 and IL-8 related molecular pathways in eKOA, and their potential relationships with consistent knee pain and physical function.

CDK5 Upregulated by ELF3 Transcription Promotes IL-1β-induced Inflammation and Extracellular Matrix Degradation in Human Chondrocytes

Osteoarthritis (OA) is a common chronic disease with age-associated increase in both incidence and prevalence. The cyclin-dependent kinase 5 (CDK5), which is a member of the CDK family, is involved in many chronic diseases. This study was performed to explore the functional role of CDK5 in OA and to discuss the detailed molecular mechanisms. The expressions of CDK5 and ELF3 before or after transfection were detected with reverse transcription-quantitative PCR (RT-qPCR) and western blot. 5-ethynyl-2'-deoxyuridine (Edu) and terminal deoxynucleoitidyl transferase-mediated nick-end labeling (TUNEL) assays were used to detect the proliferation and apoptosis of C28/I2 cells. The levels of inflammatory cytokines were estimated using enzyme-linked immunosorbent assay (ELISA) while the expressions of proteins implicated in extracellular matrix (ECM) degradation- and apoptosis were detected using western blot. Additionally, the activity of CDK5 promoters and its binding with ELF3 were detected using luciferase activity assay and chromatin immunoprecipitation (CHIP) assay. In the present study, it was discovered that the mRNA and protein expressions of CDK5 were significantly increased in IL-1β-induced C28/I2 cells. After depleting CDK5 expression, the apoptosis, inflammation and ECM in C28/I2 cells with IL-1β induction were suppressed. It was also found that ELF3 expression was increased in IL-1β-induced C28/I2 cells and acted as a transcription factor binding to the CDK5 promoter to regulate its transcriptional expression. The further experiments evidenced that ELF3 overexpression partially reversed the inhibitory effects of CDK5 deficiency on IL-1β-induced apoptosis, inflammation and ECM in C28/I2 cells. Collectively, CDK5 that upregulated by ELF3 transcription could promote the development of OA.

Development of a Microfluidic Vascularized Osteochondral Model as a Drug Testing Platform for Osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease characterized by changes in cartilage and subchondral bone. To date, there are no available drugs that can counteract the progression of OA, partly due to the inadequacy of current models to recapitulate the relevant cellular complexity. In this study, an osteochondral microfluidic model is developed using human primary cells to mimic an OA-like microenvironment and this study validates it as a drug testing platform. In the model, the cartilage compartment is created by embedding articular chondrocytes in fibrin hydrogel while the bone compartment is obtained by embedding osteoblasts, osteoclasts, endothelial cells, and mesenchymal stem cells in a fibrin hydrogel enriched with calcium phosphate nanoparticles. After developing and characterizing the model, Interleukin-1β is applied to induce OA-like conditions. Subsequently, the model potential is evaluated as a drug testing platform by assessing the effect of two anti-inflammatory drugs (Interleukin-1 Receptor antagonist and Celecoxib) on the regulation of inflammation- and matrix degradation-related markers. The model responded to inflammation and demonstrated differences in drug efficacy. Finally, it compares the behavior of the "Cartilage" and "Cartilage+Bone" models, emphasizing the necessity of incorporating both cartilage and bone compartments to capture the complex pathophysiology of OA.

Cannabiorcol as a novel inhibitor of the p38/MSK-1/NF-κB signaling pathway, reducing matrix metalloproteinases in osteoarthritis

BACKGROUND

The bioactivity and potential medicinal applications of cannabiorcol, a lesser-known derivative of Cannabis sativa, require further investigation. Osteoarthritis (OA) is a chronic joint condition marked by gradual degradation of the cartilage and commonly associated with elevated levels of matrix metalloproteinases (MMPs). However, the influence of cannabiorcol on OA and its underlying mechanisms remains unclear.

METHODS

In silico analysis investigated the key transcription factors that regulate MMP expression. A chondrocyte cell model [interleukin (IL)-1β and IL-1⍺-treated C20A4 cell line] was established and treated with cannabiorcol. Associated cytotoxicity was assessed using a WST-8 assay. A monoiodoacetate-induced OA rat model was established and treated with cannabiorcol. Protein translocation and transactivation analyses were conducted using immunofluorescence and dual-luciferase reporter assays, respectively. Western blotting and real-time PCR analyzed relevant markers to examine cannabiorcol's effects on OA and its fundamental mechanisms.

RESULTS

Cannabiorcol inhibits the expression of IL-1β-induced MMPs compared to other cannabis-related compounds. In silico analysis revealed that the nuclear factor-kappa β (NF-κβ) and mitogen-activated protein kinase (MAPK) pathways are associated with MMP expression as key regulators. In vitro, cannabiorcol inhibits the NF-κB and p38 MAPK pathways independently cannabinoid receptors and transient receptor potential vanilloids. In vivo, cannabiorcol reduces MMP expression and ameliorates monoiodoacetate-induced OA traits in rats.

CONCLUSION

Cannabiorcol inhibits IL-1β-induced MMP expression in vitro and alleviates OA in an MIA-induced OA rat model by reducing MMP expression and inhibiting the p65/p38 axis.

The association of spinal morning stiffness with lumbar disc degeneration and C-reactive protein: The back complaints in older adults (BACE) study

Objective

To determine the association between patient-reported spinal morning stiffness and lumbar disc degeneration (LDD) and systemic inflammation, as measured by C-reactive protein (CRP), in older patients with non-specific back pain. The ultimate objective is to help shape a future definition of spinal osteoarthritis (OA).

Design

Baseline data from the Dutch "Back Complaints in the Older Adults" (BACE) study was used. The relationship between the severity and duration of patient-reported spinal morning stiffness, LDD (i.e., multilevel disc space narrowing and multilevel osteophytes), and CRP was assessed. Regression models adjusted for confounding variables were performed.

Results

Six hundred and seventy-five patients were included. The mean age was 66.52 years (SD 7.69), with a mean CRP of 3.20 ​mg/L (SD 7.61). The severity of spinal morning stiffness was associated with multilevel disc space narrowing: OR 2.89 (95 ​% CI: 1.24 to 6.74) for 'mild', OR 2.97 (95 ​% CI: 1.18 to 7.44) for 'moderate', OR 3.23 (95 ​% CI: 1.17 to 8.90) for 'severe', and OR 5.62 (95 ​% CI: 1.70 to 18.60) for 'extreme' morning stiffness severity. However, spinal morning stiffness severity was not associated with multilevel osteophytes, and both multilevel features of LDD showed no associations with the duration of spinal morning stiffness. No associations were found between spinal morning stiffness severity or duration, and CRP levels.

Conclusions

Our results suggest that the severity of patient-reported spinal morning stiffness might be considered in future definitions of symptomatic spinal OA and that spinal morning stiffness is probably a symptom of a degenerative process in the spine rather than a symptom of systemic inflammation in patients with back pain.

Bone and Joint-on-Chip Platforms: Construction Strategies and Applications

Organ-on-a-chip, also known as "tissue chip," is an advanced platform based on microfluidic systems for constructing miniature organ models in vitro. They can replicate the complex physiological and pathological responses of human organs. In recent years, the development of bone and joint-on-chip platforms aims to simulate the complex physiological and pathological processes occurring in human bones and joints, including cell-cell interactions, the interplay of various biochemical factors, the effects of mechanical stimuli, and the intricate connections between multiple organs. In the future, bone and joint-on-chip platforms will integrate the advantages of multiple disciplines, bringing more possibilities for exploring disease mechanisms, drug screening, and personalized medicine. This review explores the construction and application of Organ-on-a-chip technology in bone and joint disease research, proposes a modular construction concept, and discusses the new opportunities and future challenges in the construction and application of bone and joint-on-chip platforms.

TNFα has differential effects on the transcriptome profile of selected populations in murine cartilage

Objective

To further our understanding of the role of tumor necrosis factor (TNF)α on the inflammatory response in chondrocytes.

Design

We explored the effects of TNFα on the transcriptome of epiphyseal chondrocytes from newborn C57BL/6 mice at the total and single cell (sc) resolution.

Results

Gene set enrichment analysis of total RNA-Seq from TNFα-treated chondrocytes revealed enhanced response to biotic stimulus, defense and immune response and cytokine signaling and suppressed cartilage and skeletal morphogenesis and development. scRNA-Seq analyzed 14,239 ​cells and 24,320 genes and distinguished 16 ​cell clusters. The more prevalent ones were constituted by limb bud and chondrogenic cells and fibroblasts comprising ∼73 ​% of the cell population. Genes expressed by joint fibroblasts were detected in 5 clusters comprising ∼45 ​% of the cells isolated. Pseudotime trajectory finding revealed an association between fibroblast and chondrogenic clusters which was not modified by TNFα. TNFα decreased the total cells recovered by 18.5 ​% and the chondrogenic, limb bud and mesenchymal clusters by 32 ​%, 27 ​% and 7 ​%, respectively. TNFα had profound effects on the insulin-like growth factor (IGF) axis decreasing Igf1, Igf2 and Igfbp4 and inducing Igfbp3 and Igfbp5, explaining an inhibition of collagen biosynthesis, cartilage and skeletal morphogenesis. Ingenuity Pathway Analysis of scRNA-Seq data revealed that TNFα enhanced the osteoarthritis, rheumatoid arthritis, pathogen induced cytokine storm and interleukin 6 signaling pathways and suppressed fibroblast growth factor signaling.

Conclusions

Epiphyseal chondrocytes are constituted by diverse cell populations distinctly regulated by TNFα to promote inflammation and suppression of matrix biosynthesis and growth.

Genetic proxies for therapy of insulin drug targets and risk of osteoarthritis: a drug-target Mendelian randomization analysis

BACKGROUND

The potential effects of insulin therapy on osteoarthritis (OA) risk are poorly understood. This study aimed to explore the causal relationship between insulin therapy and OA.

METHODS

Mendelian randomization (MR) analysis was performed to examine the association between genetically proxied inhibition of insulin targets and the risk of overall, hip (HOA) and knee OA (KOA). We then performed univariable MR using summary statistics regarding insulin target genes derived from the DrugBank database. Data related to blood glucose reduction levels were used as a proxy for insulin levels. Two phenotypes, type 2 diabetes, and glycosylated hemoglobin levels, were selected as positive controls to confirm the direction and validity of the proxies. The OA datasets were derived from the UK Biobank cohort. Multivariable MR was adjusted for body mass index, sedentary behavior, cigarette smoking, frequency of alcohol intake, age, and genetic sex.

RESULTS

Genetically proxied insulin therapy was associated with an increased risk of overall OA [odds ratio (OR):1.2595; 95% confidence interval (CI):1.0810-1.4675] and HOA (OR:1.4218; 95%CI:1.1240-1.7985), which remained consistent across multiple MR methods. After adjusting for confounders, we found evidence supporting a significant causal link with a higher risk of overall OA and HOA. A further two-step MR analysis revealed no significant mediation effects from the six mediators in the associations.

CONCLUSION

There was a causal association between genetically proxied insulin therapy and a higher risk of OA, especially HOA.

Associations between folate intake and knee pain, inflammation mediators and comorbid conditions in patients with symptomatic knee osteoarthritis

BACKGROUND

To investigate the associations between folate intake and changes in knee pain, inflammation mediators and comorbid conditions over 2 years in patients with symptomatic knee osteoarthritis (OA).

METHODS

A post-hoc analysis was performed based on data from the VIDEO study, a multicenter, randomized, double-blind, placebo-controlled clinical trial aimed at assessing the impact of vitamin D supplementation on patients with knee OA who were also vitamin D deficient. The original trial's design and inclusion and exclusion criteria were integrated into this subsequent post-hoc analysis. The average daily folate intake was evaluated using the Dietary Questionnaire for Epidemiological Studies version 2 over two years. The progression of knee symptoms was monitored at the baseline and then at months 3, 6, 12, and 24, utilizing the Western Ontario and McMaster Universities Index alongside a 100-mm visual analog scale. Levels of serum inflammatory mediators were quantified using ELISA techniques. Assessments of knee joint structures, leg muscle strength, depressive symptoms, feet pain, and low back pain were treated at both baseline and follow-up intervals.

RESULTS

Folate intake was correlated with reductions in overall knee pain, dysfunction, and stiffness, as well as decreased levels of Leptin and Apelin. Additionally, it was associated with enhanced leg muscle strength and diminished feet and low back pain. However, there is no association between folate intake and alterations in serum cytokine levels or knee joint structural changes. Within the subsets of overall knee pain, a significant relationship was identified between folate intake and the reduction of pain experienced when ascending or descending stairs and standing for two years.

CONCLUSIONS

Folate intake was linked with reduced knee pain, lower levels of adipokines, and a decreased prevalence of comorbid conditions in individuals with knee OA, implying that folate consumption may be associated with an improvement in knee OA symptoms, but further research is needed to verify this association.

The Therapeutic Potential of Pristimerin in Osteoarthritis: Mechanistic Insights from in vitro and in vivo Studies

Objective

Osteoarthritis (OA), a degenerative disease marked by cartilage erosion and synovial proliferation, has led to an increased interest in natural plant-based compounds to slow its progression. Pristimerin(Pri), a triterpenoid compound derived from Tripterygium wilfordii, has demonstrated anti-inflammatory and antioxidant characteristics. This study explores the protective effects of Pri on OA and its potential mechanisms.

Methods

In this study, we examined the impact of Pri on the expression of inflammatory factors and extracellular matrix(ECM) degradation induced by IL-1β in chondrocyte experiments. Bioinformatics analysis was then performed to investigate the potential signaling pathways involved in Pri's protective effects. Finally, the efficacy of Pri in reducing cartilage degradation was further evaluated in a destabilization of the medial meniscus (DMM) mouse model.

Results

Utilizing bioinformatics analysis and in vitro studies, it was revealed that Pri inhibits the activation of NF-κB and MAPK signaling pathways, leading to the reversal of upregulated MMP-13 (matrix metalloproteinases-13), iNOS (inducible nitric oxide synthase), and COX-2(cyclooxygenase-2) elicited by IL-1β stimulation, as well as the partial restoration of Collagen-II levels. Furthermore, in a DMM mouse model, the group treated with Pri exhibited reduced cartilage degradation and slowed OA progression compared to the modeling group.

Conclusion

This research highlights Pri as a potential therapeutic agent for delaying OA progression.

Efficacy of serum-free cultured human umbilical cord mesenchymal stem cells in the treatment of knee osteoarthritis in mice

BACKGROUND

We investigated the efficacy of intra-articular injection of human umbilical cord mesenchymal stem cells (hUC-MSCs) for the treatment of osteoarthritis (OA) progression in the knee joint. Although many experimental studies of hUC-MSCs have been published, these studies have mainly used fetal bovine serum-containing cultures of hUC-MSCs; serum-free cultures generally avoid the shortcomings of serum-containing cultures and are not subject to ethical limitations, have a wide range of prospects for clinical application, and provide a basis or animal experimentation for clinical experiments.

AIM

To study the therapeutic effects of serum-free hUC-MSCs (N-hUCMSCs) in a mouse model of knee OA.

METHODS

Fifty-five male C57BL/6 mice were randomly divided into six groups: The blank control group, model control group, serum-containing hUC-MSCs (S-hUCMSC) group, N-hUCMSC group and hyaluronic acid (HA) group. After 9 weeks of modeling, the serum levels of interleukin (IL)-1β and IL-1 were determined. Hematoxylin-eosin staining was used to observe the cartilage tissue, and the Mankin score was determined. Immunohistochemistry and western blotting were used to determine the expression of collagen type II, matrix metalloproteinase (MMP)-1 and MMP-13.

RESULTS

The Mankin score and serum IL-1 and IL-1β and cartilage tissue MMP-1 and MMP-13 expression were significantly greater in the experimental group than in the blank control group (P < 0.05). Collagen II expression in the experimental group was significantly lower than that in the blank control group (P < 0.05). The Mankin score and serum IL-1 and IL-1β and cartilage tissue MMP-1 and MMP-13 levels the experimental group were lower than those in the model control group (P < 0.05). Collagen II expression in the experimental group was significantly greater than that in the model control group (P < 0.05).

CONCLUSION

N-hUCMSC treatment significantly alleviate the pathological damage caused by OA. The treatment effects of the S- hUCMSC group and HA group were similar.

Screening and validation of key genes associated with osteoarthritis

BACKGROUND

Osteoarthritis is recognized as a common geriatric condition characterized by irregular chronic pain. Its prevalence is steadily increasing, posing significant challenges to global public health, while some studies indicate a trend towards younger individuals being affected. This condition severely impacts patients' quality of life.

METHODS

Using the Gene Expression Omnibus (GEO) database, we downloaded datasets GSE114007, GSE169077, and GSE206848. We utilized R software to screen and confirm differentially expressed genes (DEGs) related to the development of osteoarthritis. A cross-analysis of the three datasets was conducted, with the least overlapping dataset, GSE206848, selected as the validation set. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed on the DEGs from GSE114007 and GSE169077. Weighted Gene Co-Expression Network Analysis (WGCNA) was employed to identify modules closely associated with osteoarthritis, and genes from these intersecting modules were entered into the STRING database to construct Protein-Protein Interaction Networks. The top ten genes by connectivity were identified and validated using GSE206848. Key genes were identified and preliminarily validated using Quantitative Real-Time PCR (QPCR). Subsequent validation of related genes was carried out through Western Blot (WB) analysis.

RESULTS

Differentially expressed genes were identified from the GSE114007 and GSE169077 datasets and validated in the GSE206848 dataset, with ANGPTL4 selected as the key gene. QPCR results indicated a significant difference in ANGPTL4 expression levels between normal and osteoarthritic chondrocytes. Western Blot analysis confirmed a significant difference in ANGPTL4 protein expression between normal and osteoarthritic chondrocytes.

CONCLUSION

Based on the experimental findings, ANGPTL4 appears to be a potential key gene in osteoarthritis.

Efficacy of p62-expressing plasmid in treatment of canine osteoarthritis

Introduction

Osteoarthritis (OA) is a progressive degenerative disease of synovial joints which is highly prevalent in dogs and results in lameness, loss of joint function and mobility, chronic pain, and reduced quality of life. Traditional OA management consist of non-steroidal anti-inflammatory drugs and remains challenging because of significant side effects, thus there is an urgent need for new effective and safe therapeutics for OA.

Methods

Here we present the results of our one-arm open-label pilot clinical study of our novel biologics, a DNA plasmid encoding SQSTM/p62, in 17 companion dogs suffering from OA. The dogs were injected intramuscular with p62-plasmid once a week for 10 weeks, and pain relief was measured using the CBPI (canine brief pain inventory) validated scale. Assessment by the owners was done weekly. The 11 parameters of CBPI are grouped in three major domains: pain severity score (PSS), pain interference score (PIS) and overall impression of the quality of life (QoL).

Results

Treatment with the p62-plasmid improved all 11 parameters of CBPI as well as PSS, PIS and QoL: mean PSS score after the treatment decreased from 5.25 to 3.25, PIS score - from 7.0 to 3.27, and number of dogs with excellent and good QoL due to treatment increased from 1 to 12. Overall, the treatment success rate (i.e. a reduction ≥1 in PSS and ≥ 2 in PIS) was 90%. Importantly, similar to our previous studies with dogs and humans, no significant side effects of the p62-plasmid during the whole treatment period were observed.

Discussion

We believe that anti-inflammatory effects of the p62-plasmid, which we described in our previous works, may play an important role in observed clinical benefits and it is worthy of further studies as a novel OA treatment modality.

Inhibition of PA28γ expression can alleviate osteoarthritis by inhibiting endoplasmic reticulum stress and promoting STAT3 phosphorylation

Aims

Osteoarthritis (OA) is a common degenerative disease. PA28γ is a member of the 11S proteasome activator and is involved in the regulation of several important cellular processes, including cell proliferation, apoptosis, and inflammation. This study aimed to explore the role of PA28γ in the occurrence and development of OA and its potential mechanism.

Methods

A total of 120 newborn male mice were employed for the isolation and culture of primary chondrocytes. OA-related indicators such as anabolism, catabolism, inflammation, and apoptosis were detected. Effects and related mechanisms of PA28γ in chondrocyte endoplasmic reticulum (ER) stress were studied using western blotting, real-time polymerase chain reaction (PCR), and immunofluorescence. The OA mouse model was established by destabilized medial meniscus (DMM) surgery, and adenovirus was injected into the knee cavity of 15 12-week-old male mice to reduce the expression of PA28γ. The degree of cartilage destruction was evaluated by haematoxylin and eosin (HE) staining, safranin O/fast green staining, toluidine blue staining, and immunohistochemistry.

Results

We found that PA28γ knockdown in chondrocytes can effectively improve anabolism and catabolism and inhibit inflammation, apoptosis, and ER stress. Moreover, PA28γ knockdown affected the phosphorylation of IRE1α and the expression of TRAF2, thereby affecting the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signalling pathways, and finally affecting the inflammatory response of chondrocytes. In addition, we found that PA28γ knockdown can promote the phosphorylation of signal transducer and activator of transcription 3 (STAT3), thereby inhibiting ER stress in chondrocytes. The use of Stattic (an inhibitor of STAT3 phosphorylation) enhanced ER stress. In vivo, we found that PA28γ knockdown effectively reduced cartilage destruction in a mouse model of OA induced by the DMM surgery.

Conclusion

PA28γ knockdown in chondrocytes can inhibit anabolic and catabolic dysregulation, inflammatory response, and apoptosis in OA. Moreover, PA28γ knockdown in chondrocytes can inhibit ER stress by promoting STAT3 phosphorylation.

Therapeutic Potential of Traditional Chinese Medicine Against Osteoarthritis: Targeting the Wnt Signaling Pathway

Osteoarthritis (OA) is a chronic degenerative articular disease that leads to physical disability and reduced quality of life. The key pathological events in OA are cartilage degradation and synovial inflammation. Conventional therapies often lead to adverse effects that some patients are unwilling to endure. Traditional Chinese Medicines (TCMs) have long been known for their efficacy in treating OA with minimal side effects. The wingless-type (Wnt) signaling pathway is believed to play a role in OA progression, but there is still a lack of comprehensive understanding on how TCM may treat OA via the Wnt signaling pathway. This study aims to fill this gap by reviewing relevant research on the association between the Wnt signaling pathway and cartilage degradation and synovial inflammation in OA. Meanwhile, we also summarized and categorized TCMs and their active components, such as alkaloids, polysaccharides, flavonoids, sesquiterpene lactones, etc., which have shown varying efficacy in treating OA through modulation of the Wnt/[Formula: see text]-catenin signaling pathway. This work underscores the pivotal role of the Wnt signaling pathway in OA pathogenesis and progression, suggesting that targeting this pathway holds promise as a prospective therapeutic strategy for OA management in the future. TCMs and their active components have the potential to alleviate OA by modulating the Wnt signaling cascade. Harnessing TCMs and their active components to regulate the Wnt signaling pathway presents an encouraging avenue for delivering substantial therapeutic benefits to individuals with OA.

Mitoregulin modulates inflammation in osteoarthritis: Insights from synovial transcriptomics and cellular studies

Osteoarthritis is a prevalent musculoskeletal disease that involves cartilage degradation, subchondral bone remodeling, and synovial inflammation and ultimately causes physical disability. Common risk factors for osteoarthritis include age, sex, obesity, and genetic predispositions. Treatment includes nonpharmaceutical and pharmacological approaches; however, disease-modifying osteoarthritis drugs remain undeveloped. We aimed to identify key regulatory factors underlying the etiology of osteoarthritis. We studied alterations of the inflammatory responses after manipulating the expression of MTLN, which we selected after sequencing and transcriptomics of the patients' synovial tissues. MTLN expression was increased in synovial tissues of patients and in SW982 human synovial sarcoma cells following inflammatory stimuli. We found that MTLN overexpression or knockout respectively decreased or increased expression of the inflammation-associated genes, including IL-6, IL-8, and TNF-α. Thus, high levels of MTLN in osteoarthritis may protect tissues against excessive inflammation, thereby offering therapeutic potentials.

Pinus densiflora Root Extract Attenuates Osteoarthritis Progression by Inhibiting Inflammation and Cartilage Degradation in Interleukin-1β and Monosodium Iodoacetate-Induced Osteoarthritis Models

BACKGROUND

Osteoarthritis (OA) is a common degenerative joint condition caused by an imbalance between cartilage synthesis and degradation, which disrupts joint homeostasis. This study investigated the anti-inflammatory and joint-improving effects of Pinus densiflora root extract powder (PDREP) in both in vitro and in vivo OA models.

METHODS/RESULTS

In an in vitro OA model, in which SW1353 human chondrosarcoma cells were treated with interleukin (IL)-1β, PDREP treatment significantly reduced the mRNA levels of matrix metalloproteinase (MMP)-1, MMP-3, and MMP-13 while enhancing collagen type II alpha 1 (Col2a1) mRNA level, and decreased IL-6 and prostaglandin E2 (PGE2) levels. In addition, PDREP inhibited the phosphorylation of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinase (JNK), p38, nuclear factor-kappa B (NF-κB), and the expression of inducible nitric oxide synthase (iNOS). In a monosodium iodoacetate (MIA)-induced OA rat model, the administration of PDREP resulted in decreased OA clinical indices, improved weight-bearing indices and gait patterns, reduced histological damage, and lowered serum inflammatory cytokine and MMPs expression. Furthermore, PDREP downregulated the phosphorylation of ERK, JNK, p38, and NF-κB, as well as the expression of iNOS, consistent with the in vitro findings.

CONCLUSIONS

These results suggest that PDREP exhibits anti-inflammatory and joint-improving effects and has potential as a therapeutic strategy or functional food for the treatment of OA.

Small molecule inhibitors of IL-1R1/IL-1β interaction identified via transfer machine learning QSAR modelling

The human interleukin-1 receptor I (IL-1R1) is a cytokine receptor recognized by interleukin 1β (IL-1β), among other cytokines. Over activation of IL-1R1 has been implicated in various inflammatory conditions. This research aims to identify small-molecule inhibitors targeting the hIL1R1/IL1β interaction, employing a multi-task transfer learning approach for quantitative structure-activity relationship (QSAR) modelling. A comprehensive bioactivity dataset from functionally related proteins was utilised to build a robust ensemble machine learning model for predicting IC50 values against the target protein. Despite the availability of antibody-based therapies, the absence of orally available small-molecule inhibitors necessitates their development. By combining model predictions with docking and simulation approaches, the interleukin-1 receptor inhibitor (IRI-1) emerged as a lead compound. It potently inhibited human IL1-R1 with micromolar activity in THP-1 and Saos-2 cells and demonstrated good biocompatibility. Western blot analysis revealed that IRI-1 inhibits IL-1β-mediated phosphorylation of IL1-R1, JNK, IRAK-4, and ERK in THP-1 cells. Furthermore, molecular dynamics simulations confirmed the structural stability of the protein-ligand complexes. This study highlights the effectiveness of multi-task transfer learning approaches for building robust QSAR models against novel proteins or those with limited bioactivity data, such as hIL-1β/IL-1R1 protein.

MSC-microvesicles protect cartilage from degradation in early rheumatoid arthritis via immunoregulation

OBJECTIVE

As research into preclinical rheumatoid arthritis (pre-RA) has advanced, a growing body of evidence suggests that abnormalities in RA-affected joint cartilage precede the onset of arthritis. Thus, early prevention and treatment strategies are imperative. In this study, we aimed to explore the protective effects of mesenchymal stem cell (MSC)-derived microvesicles (MVs) on cartilage degradation in a collagen-induced arthritis (CIA) mouse model.

METHODS

A CIA mouse model was established to observe early pathological changes in cartilage (days 21-25) through histological and radiological examinations. On day 22, MSCs-MVs were intravenously injected into the mice with CIA. Radiological, histological, and flow cytometric examinations were conducted to observe inflammation and cartilage changes in these mice compared to the mice with CIA and the control mice. In vitro, chondrocytes were cultured with inflammatory factors such as IL-1β and TNFα to simulate inflammatory damage to cartilage. After the addition of MVs, changes in inflammatory levels and collagen expression were measured via Western blotting, immunofluorescence, enzyme-linked immunosorbent assays (ELISAs), and quantitative PCR to determine the role of MVs in maintaining chondrocytes.

RESULTS

MSC-MVs expressed vesicular membrane proteins (CD63 and Annexin V) and surface markers characteristic of MSCs (CD44, CD73, CD90, and CD105). In the early stages of CIA in mice, a notable decrease in collagen content was observed in the joint cartilage. In mice with CIA, injection of MSCs-MVs resulted in a significant reduction in the peripheral blood levels of IL-1β, TNFα, and IL-6, along with a decrease in the ratio of proinflammatory T and B cells. Additionally, MSC-MVs downregulated the expression of IL-1β, TNFα, MMP-13, and ADAMTS-5 in cartilage while maintaining the stability of type I and type II collagen. These MVs also attenuated the destruction of cartilage, which was evident on imaging. In vitro experiments demonstrated that MSC-MVs effectively suppressed the secretion of the inflammatory factors IL-1β, TNFα, and IL-6 in stimulated peripheral blood mononuclear cells (PBMCs).

CONCLUSIONS

MSCs-MVs can inhibit the decomposition of the inflammation-induced cartilage matrix by regulating immune cell inflammatory factors to attenuate cartilage destruction. MSC-MVs are promising effective treatments for the early stages of RA.

Pathogenesis of osteoarthritis, rheumatoid arthritis, and hemophilic arthropathy: The role of angiogenesis

INTRODUCTION

The term 'chronic inflammatory arthritis' (IA) can be used to define a group of heterogeneous diseases in which inflammation of the synovium is the common feature while having different pathogenesis and clinical outcomes. This condition can be found in osteoarthritis (OA), rheumatoid arthritis (RA), and hemophilic arthropathy (HA).

AIM

The objective is to try to highlight similarities and differences in the three pathological conditions and understand both molecular and physiological mechanisms.

METHOD

We have carried out a systematic review of the available literature following the guidelines Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA).

RESULTS

By comparing the data in the literature on OA, RA, and HA we have shown that the three pathologies differ in initial etiology but they motivate the same molecular pathways.

CONCLUSION

In this review we highlighted the similarities and differences between these diseases, creating ideas for future studies both in vivo and in vitro to develop new therapeutic agents and suggest possible biomarkers to follow the evolution and severity of the disease.

Metallothionein-1 mitigates the advancement of osteoarthritis by regulating Th17/Treg balance

Osteoarthritis (OA) is a chronic inflammatory joint disorder characterized by cartilage degradation and bone remodeling. This study investigated the regulatory role of metallothionein 1 (MT1) in modulating immune responses and the balance between regulatory T cells (Treg) and T helper 17 cells (Th17) in OA. Peripheral blood mononuclear cells (PBMCs) from healthy individuals and OA patients were assessed for cytokine expression linked to Treg/Th17 homeostasis. OA was induced in wild-type (WT) and Mt1 knockout (MT1KO) mice via surgical destabilization of the medial meniscus. Clinical scores, pathological features, inflammatory cytokines, and Treg/Th17 balance were evaluated. MT1KO mice showed significantly elevated Mt1, pro-inflammatory cytokines (IL-1, IL-6, TNF-α) and exacerbated OA progression, characterized by increased knee joint diameter, inflammatory infiltration, and cartilage destruction. Mechanistically, disrupted Treg/Th17 balance played a pivotal role in OA exacerbation, with MT1KO promoting Th17 differentiation and reducing Treg populations. Additionally, the compensatory elevation of anti-inflammatory interleukin-10 (IL-10) in OA patients hinted at a nuanced immune regulatory mechanism. The study illuminates intricate interactions involving MT1, Treg/Th17 cells, and pro-inflammatory cytokines in OA pathogenesis, suggesting MT1's potential as a pivotal regulatory factor and a therapeutic target for mitigating immune dysregulation in OA.

Cartilage lacuna-biomimetic hydrogel microspheres endowed with integrated biological signal boost endogenous articular cartilage regeneration

Despite numerous studies on chondrogenesis, the repair of cartilage-particularly the reconstruction of cartilage lacunae through an all-in-one advanced drug delivery system remains limited. In this study, we developed a cartilage lacuna-like hydrogel microsphere system endowed with integrated biological signals, enabling sequential immunomodulation and endogenous articular cartilage regeneration. We first integrated the chondrogenic growth factor transforming growth factor-β3 (TGF-β3) into mesoporous silica nanoparticles (MSNs). Then, TGF-β3@MSNs and insulin-like growth factor 1 (IGF-1) were encapsulated within microspheres made of polydopamine (pDA). In the final step, growth factor-loaded MSN@pDA and a chitosan (CS) hydrogel containing platelet-derived growth factor-BB (PDGF-BB) were blended to produce growth factors loaded composite microspheres (GFs@μS) using microfluidic technology. The presence of pDA reduced the initial acute inflammatory response, and the early, robust release of PDGF-BB aided in attracting endogenous stem cells. Over the subsequent weeks, the continuous release of IGF-1 and TGF-β3 amplified chondrogenesis and matrix formation. μS were incorporated into an acellular cartilage extracellular matrix (ACECM) and combined with a polydopamine-modified polycaprolactone (PCL) structure to produce a tissue-engineered scaffold that mimicked the structure of the cartilage lacunae evenly distributed in the cartilage matrix, resulting in enhanced cartilage repair and patellar cartilage protection. This research provides a strategic pathway for optimizing growth factor delivery and ensuring prolonged microenvironmental remodeling, leading to efficient articular cartilage regeneration.

CCL4/CCR5 regulates chondrocyte biology and OA progression

BACKGROUND

Osteoarthritis (OA) is a common musculoskeletal disorder characterized by chondrocyte apoptosis and extracellular matrix degradation. This study aimed to investigate the role of CCL4/CCR5 in regulating chondrocyte apoptosis and reactive oxygen species (ROS) levels in OA progression.

METHODS

Bioinformatics analysis was employed to identify CCL4 as the target gene, following which primary chondrocytes were treated with varying concentrations of CCL4. Apoptosis rate of chondrocytes and ROS levels were assessed using flow cytometry. The mechanism by which CCL4 regulated the extracellular matrix was investigated through Western blot and Immunofluorescence analyses. Additionally, maraviroc, a CCR5 inhibitor, was administered to chondrocytes in order to explore the potential signaling pathway of CCL4/CCR5.

RESULTS

Our study found that CCL4 was predominantly up-regulated among the top 10 hub genes identified in RNA-sequencing analysis. Validation through quantitative polymerase chain reaction (qPCR) confirmed elevated CCL4 expression in patients with Hip joint osteoarthritis, knee joint osteoarthritis, and facet joint osteoarthritis. The upregulation of CCL4 was associated with an increase in chondrocyte apoptosis and ROS levels. Mechanistically, CCL4, upon binding to its receptor CCR5, triggered the downstream phosphorylation of P65 in the nuclear factor-κB (NF-κB) signaling pathway. In vitro experiments demonstrated that treatment with maraviroc mitigated chondrocyte apoptosis, reduced intracellular ROS levels, and attenuated extracellular matrix degradation.

CONCLUSION

The study highlights the critical role of CCL4/CCR5 in modulating chondrocyte apoptosis and ROS levels in OA progression. Targeting this pathway may offer promising therapeutic interventions for mitigating the pathogenic mechanisms associated with OA.

Ubiquitination and deubiquitination: Implications for the pathogenesis and treatment of osteoarthritis

Osteoarthritis (OA) is a degenerative disease that affects multiple cells and associated extracellular matrix (ECM). Chondrocytes and chondroextracellular matrix together constitute articular cartilage tissue. Any factors that affect the activity of chondrocytes and destroy the metabolic balance of the chondrocyte ECM will lead to the inability of articular cartilage to perform normal functions. The articular subchondral bone and articular cartilage must be coordinated to resist enough friction and mechanical stress, so the articular subchondral bone lesion will aggravate the articular cartilage defect and vice versa. Synoviocytes, including fibroblast-like synoviocytes (FLSs) and synovial macrophages at the joint, are also important factors that cause low-grade chronic progressive inflammation of OA. Regulation of phenotype transformation of synovial macrophages has become another possible target for the clinical treatment of OA. Ubiquitination and deubiquitination are the main post-translational protein modification pathways in the human body, which are widely involved in multiple signaling pathways and physiological processes. Naturally, they also play a very important regulatory role in the occurrence and development of OA. These effects are summarized in this review, including (A) regulating the aging and apoptosis of chondrocytes, FLSs and osteoblasts; (B) regulation of ECM degradation; (C) regulation of macrophage phenotypic transformation; (D) modulation of skeletal muscle and adipose tissues. Ubiquitination targeting drugs for OA treatment are also listed. Depending on the high efficiency of ubiquitination and deubiquitination, understanding OA-related ubiquitination pathways can help design more efficient drugs to treat OA and provide more potential targets for clinical treatment. The Translational Potential of This Article. In this paper, the ubiquitination-related pathways in osteoarthritis (OA), including aging, apoptosis and autophagy in chondrocytes, osteoblasts, FLSs and macrophages were investigated. In particular, several ubiquitination-related targets are expected to be effective approaches for OA clinical treatment. In addition, in the process of OA occurrence and development, the complex relationship between the local joint area and other tissues including skeletal muscle and adipose tissue is also discussed. These myokines and adipokines from musculoskeletal tissues are all expected to become efficient targets for OA treatment apart from the joint itself. In addition, those myokines secreted by cardiovascular tissues would show potential therapeutic effects as well. What if altering the contents for these ubiquitination-related targets in the serum through exercise will provide a new idea for OA therapy or prevent OA from deteriorating continuously?

Emerging role and function of Hippo-YAP/TAZ signaling pathway in musculoskeletal disorders

Hippo pathway is an evolutionarily conservative key pathway that regulates organ size and tissue regeneration by regulating cell proliferation, differentiation and apoptosis. Yes-associated protein 1 (YAP)/ WW domain-containing transcription regulator 1 (TAZ) serves as a pivotal transcription factor within the Hippo signaling pathway, which undergoes negative regulation by the Hippo pathway. The expression of YAP/TAZ affects various biological processes, including differentiation of osteoblasts (OB) and osteoclasts (OC), cartilage homeostasis, skeletal muscle development, regeneration and quality maintenance. At the same time, the dysregulation of the Hippo pathway can concurrently contribute to the development of various musculoskeletal disorders, including bone tumors, osteoporosis (OP), osteoarthritis (OA), intervertebral disc degeneration (IDD), muscular dystrophy, and rhabdomyosarcoma (RMS). Therefore, targeting the Hippo pathway has emerged as a promising therapeutic strategy for the treatment of musculoskeletal disorders. The focus of this review is to elucidate the mechanisms by which the Hippo pathway maintains homeostasis in bone, cartilage, and skeletal muscle, while also providing a comprehensive summary of the pivotal role played by core components of this pathway in musculoskeletal diseases. The efficacy and feasibility of Hippo pathway-related drugs for targeted therapy of musculoskeletal diseases are also discussed in our study. These endeavors offer novel insights into the application of Hippo signaling in musculoskeletal disorders, providing effective therapeutic targets and potential drug candidates for treating such conditions.

Development and evaluation of 3D composite scaffolds with piezoelectricity and biofactor synergy for enhanced articular cartilage regeneration

The inability of articular cartilage to self-repair following injuries frequently precipitates osteoarthritis, profoundly affecting patients' quality of life. Given the limitations inherent in current clinical interventions, an urgent need exists for more effective cartilage regeneration methodologies. Previous studies have underscored the potential of electrical stimulation in cartilage repair, thus motivating the investigation of innovative strategies. The present study introduces a three-dimensional scaffold fabricated through a composite technique that leverages the synergy between piezoelectricity and biofactors to enhance cartilage repair. This scaffold is composed of polylactic acid (PLLA) and barium titanate (BT) for piezoelectric stimulation and at the bottom with a collagen-coated layer infused with fibroblast growth factor-18 (FGF-18) for biofactor delivery. Designed to emulate the properties of natural cartilage, the scaffold enables controlled generation of piezoelectric charges and the sustained release of biofactors. In vitro tests confirm that the scaffold promotes chondrocyte proliferation, matrix hyperplasia, cellular migration, and the expression of genes associated with cartilage formation. Moreover, in vivo studies on rabbits have illustrated its efficacy in catalyzing the in situ regeneration of articular cartilage defects and remodeling the extracellular matrix. This innovative approach offers significant potential for enhancing cartilage repair and holds profound implications for regenerative medicine.

Spermidine protects cartilage from IL-1β-mediated ferroptosis

Rheumatoid arthritis is characterized by a burst of inflammation, the destruction of cartilage and the abundant release of inflammatory factors such as IL-1β. Thus, the effect of IL-1β on cartilage was examined in this study. IL-1β could cause lipid peroxidation and disturbances in iron metabolism by increasing the expression of NCOA4 and decreasing the expression of FTH, which also induced ferritinophagy. In addition, the expression of the key antioxidant proteins SLC7A11 and GPX4 was inhibited by IL-1β, resulting in ferroptosis in chondrocytes. Spermidine (SPD), a low-molecular-weight aliphatic nitrogen-containing compound that widely exists in animals, has been reported to be an antioxidant. In our study, we found that SPD could inhibit ferritinophagy and reverse the decrease in the expression of SLC7A11 and GPX4. Therefore, we uncovered one of the molecular mechanisms of cartilage destruction and inflammation and provide a potential polyamine for the treatment of RA.

Targeting PAR2-mediated inflammation in osteoarthritis: a comprehensive in vitro evaluation of oleocanthal's potential as a functional food intervention for chondrocyte protection and anti-inflammatory effects

BACKGROUND

Osteoarthritis (OA) is a prevalent degenerative joint disease characterized by chronic inflammation and progressive cartilage degradation, ultimately leading to joint dysfunction and disability. Oleocanthal (OC), a bioactive phenolic compound derived from extra virgin olive oil, has garnered significant attention due to its potent anti-inflammatory properties, which are comparable to those of non-steroidal anti-inflammatory drugs (NSAIDs). This study pioneers the investigation into the effects of OC on the Protease-Activated Receptor-2 (PAR-2) mediated inflammatory pathway in OA, aiming to validate its efficacy as a functional food-based therapeutic intervention.

METHODS

To simulate cartilage tissue in vitro, human bone marrow-derived mesenchymal stem cells (BMSCs) were differentiated into chondrocytes. An inflammatory OA-like environment was induced in these chondrocytes using lipopolysaccharide (LPS) to mimic the pathological conditions of OA. The therapeutic effects of OC were evaluated by treating these inflamed chondrocytes with various concentrations of OC. The study focused on assessing key inflammatory markers, catabolic enzymes, and mitochondrial function to elucidate the protective mechanisms of OC. Mitochondrial function, specifically mitochondrial membrane potential (ΔΨm), was assessed using Rhodamine 123 staining, a fluorescent dye that selectively accumulates in active mitochondria. The integrity of ΔΨm serves as an indicator of mitochondrial and bioenergetic function. Additionally, Western blotting was employed to analyze protein expression levels, while real-time polymerase chain reaction (RT-PCR) was used to quantify gene expression of inflammatory cytokines and catabolic enzymes. Flow cytometry was utilized to measure cell viability and apoptosis, providing a comprehensive evaluation of OC's therapeutic effects on chondrocytes.

RESULTS

The results demonstrated that OC significantly downregulated PAR-2 expression in a dose-dependent manner, leading to a substantial reduction in pro-inflammatory cytokines, including TNF-α, IL-1β, and MCP-1. Furthermore, OC attenuated the expression of catabolic markers such as SOX4 and ADAMTS5, which are critically involved in cartilage matrix degradation. Importantly, OC was found to preserve mitochondrial membrane potential (ΔΨm) in chondrocytes subjected to inflammatory stress, as evidenced by Rhodamine 123 staining, indicating a protective effect on cellular bioenergetics. Additionally, OC modulated the Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL)/Receptor Activator of Nuclear Factor Kappa-Β (RANK) pathway, suggesting a broader therapeutic action against the multifactorial pathogenesis of OA.

CONCLUSIONS

This study is the first to elucidate the modulatory effects of OC on the PAR-2 mediated inflammatory pathway in OA, revealing its potential as a multifaceted therapeutic agent that not only mitigates inflammation but also protects cartilage integrity. The preservation of mitochondrial function and modulation of the RANKL/RANK pathway further underscores OC's comprehensive therapeutic potential in counteracting the complex pathogenesis of OA. These findings position OC as a promising candidate for integration into nutritional interventions aimed at managing OA. However, further research is warranted to fully explore OC's therapeutic potential across different stages of OA and its long-term effects in musculoskeletal disorders.

Characterization and immune role of class B scavenger receptor member 1 in spotted sea bass (Lateolabrax maculatus)

Scavenger receptors (SRs) are integral to the innate immune system and function as pattern-recognition receptors that facilitate pathogen clearance and mediate anti-inflammatory responses. However, the role of SRs in the immune response of Lateolabrax maculatus against Aeromonas veronii is unclear. Here, we cloned scavenger receptor B1 from L. maculatus (LmSRB1) and performed bioinformatics analysis to study its potential functions. The open reading frame spans 1530 base pairs and encodes a 509-amino acid protein with a molecular mass of 57.44 kDa. Comparative analysis revealed high sequence conservation among fish species. Expression profiling revealed strong LmSRB1 transcription in various tissues, especially in head kidney and spleen. Following A. veronii exposure, LmSRB1 expression initially increased, peaking after 4-8 h, with a notable secondary peak at 72 h. Fluorescence in situ hybridization indicated that LmSRB1 mainly localized to the cytoplasm, and subcellular-localization studies confirmed LmSRB1 protein expression in the cytoplasm and cell membrane. Enzyme-linked immunosorbent assay data showed dose-dependent binding of LmSRB1 to A. veronii. Modulating LmSRB1 expression significantly altered the levels of IL-8, IL-1β, TRAF6, and NIK. These results highlight the crucial role of LmSRB1 in L. maculatus's innate immune response to A. veronii and offer insights into improving the management of bacterial infections in aquaculture.

FTO-mediated SMAD2 m6A modification protects cartilage against Osteoarthritis

N6-methyladenosine (m6A) modification is one of the most prevalent forms of epigenetic modification and plays an important role in the development of degenerative diseases such as osteoarthritis (OA). However, the evidence concerning the role of m6A modification in OA is insufficient. Here, m6A modification was increased in human OA cartilage and degenerated chondrocytes. Among all of the m6A enzymes, the expression of the demethylase fat mass and obesity-associated protein (FTO) decreased dramatically. Conditional knockout of FTO in chondrocytes accelerates OA progression. FTO transcription is regulated by runt-related transcription factor-1 (RUNX1). Reduced FTO elevates m6A modification at the adenosine N6 position in SMAD family member 2 (SMAD2) mRNA, whose stability is subsequently modulated by the recruited m6A reader protein YTH N6-methyladenosine RNA binding protein F2 (YTHDF2). Collectively, these findings reveal the function and mechanism of the m6A family member FTO in OA progression. Therefore, reducing m6A modification to increase SMAD2 stability by activating FTO might be a potential therapeutic strategy for OA treatment.

Association of Undercorrection With Residual Proinflammatory Gene Expressions and Clinical Outcomes After Medial Open Wedge Proximal Tibial Osteotomy

BACKGROUND

Accumulating evidence suggests that synovial inflammation plays a pivotal role in knee osteoarthritis. Although biomechanical findings have shown that medial open-wedge proximal tibial osteotomy (OWPTO) decreases medial compartment loading by correcting knee alignment, the relationship between knee alignment and synovial inflammation in the biological microenvironment has not yet been elucidated.

PURPOSES

To investigate the relationship between preoperative and postoperative knee alignment and synovial gene expression and to determine the cutoff point of postoperative knee alignment at which gene expression of synovial inflammation improves.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 36 patients with osteoarthritis who underwent OWPTO between June 2018 and May 2020 were enrolled. Synovial tissue was collected from affected knees during initial OWPTO and plate removal surgeries, and gene expression associated with the pathogenesis of osteoarthritis in the synovial tissue was investigated using real-time polymerase chain reaction. The correlation between weightbearing line ratio (WBLR) and synovial gene expression was determined. Receiver operating characteristic curve analysis was used to determine the cutoff values of WBLR for improving gene expression. The participants were divided into 2 groups, according to the cutoff values of their WBLR, and compared according to Knee injury and Osteoarthritis Outcome Score (KOOS) and synovial gene expression.

RESULTS

Postoperative WBLR was correlated with gene expression of interleukin 1β (IL1B) (ρ = -0.43; P = .008) and of interleukin 6 (IL6) (ρ = -0.41; P = .01). The cutoff value to predict improvement of IL6 was postoperative WBLR of 52%, with an area under the curve of 0.74 (P = .03). Patients with WBLR of <52% showed higher postoperative inflammatory gene (IL1B [P = .04] and IL6 [P = .03]) and inferior postoperative KOOS values compared with those with WBLR of >52%.

CONCLUSION

The novel cutoff alignment for biological improvement after OWPTO in patients with medial compartment osteoarthritis was determined to be WBLR of 52%, and WBLR of <52% was associated with higher residual intra-articular inflammation and poor clinical outcomes. After accounting for surgical errors, the surgeon should set the target surgical alignment so that the postoperative WBLR does not fall below 52%.

Angiogenesis unveiled: Insights into its role and mechanisms in cartilage injury

Osteoarthritis (OA) commonly results in compromised mobility and disability, thereby imposing a significant burden on healthcare systems. Cartilage injury is a prevalent pathological manifestation in OA and constitutes a central focus for the development of treatment strategies. Despite the considerable number of studies aimed at delaying this degenerative process, their outcomes remain unvalidated in preclinical settings. Recently, therapeutic strategies focused on angiogenesis have attracted the growing interest from researchers. Thus, we conducted a comprehensive literature review to elucidate the current progress in research and pinpoint research gaps in this domain. Additionally, it provides theoretical guidance for future research endeavors and the development of treatment strategies.

Therapeutic framework nucleic acid complexes targeting oxidative stress and pyroptosis for the treatment of osteoarthritis

Osteoarthritis (OA) is one of the most prevalent joint diseases and severely affects the quality of life in the elderly population. However, there are currently no effective prevention or treatment options for OA. Oxidative stress and pyroptosis play significant roles in the development and progression of OA. To address this issue, we have developed a novel therapeutic approach for OA that targets oxidative stress and pyroptosis. We synthesized tetrahedral framework nucleic acid (tFNAs) to form framework nucleic acid complexes (TNCs), which facilitate the delivery of the naturally occurring polymethoxyflavonoid nobiletin (Nob) to chondrocytes. TNC has demonstrated favorable bioavailability, stability, and biosafety for delivering Nob. Both in vitro and in vivo experiments have shown that TNC can alleviate OA and protect articular cartilage from damage by eliminating oxidative stress, inhibiting pyroptosis, and restoring the extracellular matrix anabolic metabolism of chondrocytes. These findings suggest that TNC has significant potential in the treatment of OA and cartilage injury.

Etodolac utility in osteoarthritis: drug delivery challenges, topical nanotherapeutic strategies and potential synergies

Osteoarthritis (OSA) is a prevalent joint disorder characterized by losing articular cartilage, primarily affecting the hip, knee and spine joints. The impact of OSA offers a major challenge to health systems globally. Therapeutic approaches encompass surgical interventions, non-pharmacological therapies (exercise, rehabilitation, behavioral interventions) and pharmacological treatments. Inflammatory processes within OSA joints are regulated by pro-inflammatory and anti-inflammatory cytokines. Etodolac, a COX-2-selective inhibitor, is the gold standard for OSA management and uniquely does not inhibit gastric prostaglandins. This comprehensive review offers insights into OSA's pathophysiology, genetic factors and biological determinants influencing disease progression. Emphasis is placed on the pivotal role of etodolac in OSA management, supported by both preclinical and clinical evidences in topical drug delivery. Notably, in-silico docking studies suggested potential synergies between etodolac and baicalein, considering ADAMTS-4, COX-2, MMP-3 and MMP-13 as essential therapeutic targets. Integration of artificial neural network (ANN) techniques with nanotechnology approaches emerges as a promising strategy for optimizing and personalizing topical etodolac delivery. Furthermore, the synergistic potential of etodolac and baicalein warrants in-depth exploration. Hence, by embracing cutting-edge technologies like ANN and nanomedicine, the optimization of topical etodolac delivery could guide a new era of OSA treatment.

Prevalence and Associated Factors of Musculoskeletal Disorders among Older Patients Treated at Walailak University Physical Therapy Clinic in Thailand: A Retrospective Study

The prevalence of musculoskeletal disorders (MSDs) is high among older adults worldwide, significantly affecting their quality of life and overall health. Understanding the prevalence of MSDs and their associated factors is crucial to developing effective preventive and management strategies in Thailand. In this study, we aimed to investigate the prevalence of MSDs and their associated factors among older patients at Walailak University Physical Therapy Clinic. In this retrospective study, we analyzed the medical records of 396 older patients. Data on demographics, underlying diseases, career types, and treatments were collected and analyzed using descriptive statistics chi-squared tests, and logistic regression analysis to determine their associations with MSD prevalence. The overall prevalence of MSDs was 89.90%. MSD prevalence was higher among female patients than among male patients (p < 0.001). The most commonly affected body regions were the lower back, shoulders, and knees. Career type (p < 0.001) had the highest impact on the presence of MSDs after controlling for sex, age, and underlying diseases as covariates in a logistic regression model. Manual labor and heavy industry workers as well as pensioners showed an increased risk of MSDs. While older age was associated with a higher MSD prevalence using chi-squared statistics, it was removed from the logistic regression models. Pensioners were the most likely to receive treatment, indicating the need for targeted interventions for individuals with physically demanding occupations. These findings underscore the importance of targeted interventions and further research on socioeconomic factors, lifestyle behaviors, and comorbidities to manage MSDs among older adults in Thailand.

Deciphering the Role of LncRNAs in Osteoarthritis: Inflammatory Pathways Unveiled

Long non-coding RNA (LncRNA), with transcripts over 200 nucleotides in length, play critical roles in numerous biological functions and have emerged as significant players in the pathogenesis of osteoarthritis (OA), an inflammatory condition traditionally viewed as a degenerative joint disease. This review comprehensively examines the influence of LncRNA on the inflammatory processes driving OA progression, focusing on their role in regulating gene expression, cellular activities, and inflammatory pathways. Notably, LncRNAs such as MALAT1, H19, and HOTAIR are upregulated in OA and exacerbate the inflammatory milieu by modulating key signaling pathways like NF-κB, TGF-β/SMAD, and Wnt/β-catenin. Conversely, LncRNA like MEG3 and GAS5, which are downregulated in OA, show potential in dampening inflammatory responses and protecting against cartilage degradation by influencing miRNA interactions and cytokine production. By enhancing our understanding of LncRNA' roles in OA inflammation, we can better leverage them as potential biomarkers for the disease and develop innovative therapeutic strategies for OA management. This paper aims to delineate the mechanisms by which LncRNA influence inflammatory responses in OA and propose them as novel targets for therapeutic intervention.

Targeting Parkin-regulated metabolomic change in cartilage in the treatment of osteoarthritis

Articular cartilage degeneration may lead to osteoarthritis (OA) during the aging process, but its underlying mechanism remains unknown. Here, we found that chondrocytes exhibited an energy metabolism shift from glycolysis to oxidative phosphorylation (OXPHOS) during aging. Parkin regulates various cellular metabolic processes. Reprogrammed cartilage metabolism by Parkin ablation decreased OXPHOS and increased glycolysis, with ameliorated aging-related OA. Metabolomics analysis indicated that lauroyl-L-carnitine (LLC) was decreased in aged cartilage, but increased in Parkin-deficient cartilage. In vitro, LLC improved the cartilage matrix synthesis of aged chondrocytes. In vivo, intra-articular injection of LLC in mice with anterior cruciate ligament transaction (ACLT) ameliorated OA progression. These results suggest that metabolic changes are regulated by Parkin-impaired cartilage during aging, and targeting this metabolomic changes by supplementation with LLC is a promising treatment strategy for ameliorating OA.

Glucagon-like peptide-1 receptor: mechanisms and advances in therapy

The glucagon-like peptide-1 (GLP-1) receptor, known as GLP-1R, is a vital component of the G protein-coupled receptor (GPCR) family and is found primarily on the surfaces of various cell types within the human body. This receptor specifically interacts with GLP-1, a key hormone that plays an integral role in regulating blood glucose levels, lipid metabolism, and several other crucial biological functions. In recent years, GLP-1 medications have become a focal point in the medical community due to their innovative treatment mechanisms, significant therapeutic efficacy, and broad development prospects. This article thoroughly traces the developmental milestones of GLP-1 drugs, from their initial discovery to their clinical application, detailing the evolution of diverse GLP-1 medications along with their distinct pharmacological properties. Additionally, this paper explores the potential applications of GLP-1 receptor agonists (GLP-1RAs) in fields such as neuroprotection, anti-infection measures, the reduction of various types of inflammation, and the enhancement of cardiovascular function. It provides an in-depth assessment of the effectiveness of GLP-1RAs across multiple body systems-including the nervous, cardiovascular, musculoskeletal, and digestive systems. This includes integrating the latest clinical trial data and delving into potential signaling pathways and pharmacological mechanisms. The primary goal of this article is to emphasize the extensive benefits of using GLP-1RAs in treating a broad spectrum of diseases, such as obesity, cardiovascular diseases, non-alcoholic fatty liver disease (NAFLD), neurodegenerative diseases, musculoskeletal inflammation, and various forms of cancer. The ongoing development of new indications for GLP-1 drugs offers promising prospects for further expanding therapeutic interventions, showcasing their significant potential in the medical field.

Similar Pathophysiological Mechanisms Between Osteoarthritis and Vascular Disease

Osteoarthritis (OA) is a prevalent, chronic joint disorder affecting millions of people worldwide, characterized by articular cartilage degradation, subchondral bone remodeling, synovial cytokine secretion, and osteophyte formation. OA primarily affects the hips, knees, hands, and spine. Patients with OA exhibit a higher prevalence of cardiovascular comorbidities and potentially important associations between OA and cardiovascular diseases have prompted investigations into potentially similar pathophysiological associations. This review explores the coexistence of atherosclerotic peripheral vascular disease (ASPVD) in OA patients, including evidence from a contemporary study suggesting associations between OA and arterial wall thickness and blood flow changes which are characteristic of early atherosclerosis, and which stimulate reactive pathology in endothelial cells. Observations from this study demonstrate elevated arterial flow volume and increased intima-media thickness in arteries ipsilateral to OA knees, suggesting a potential link between OA and arterial wall disease. We further explore the intricate relationship between the vascular system and skeletal health, highlighting bidirectional interactions among endothelial cells, inflammatory cells, and various bone cells. Mechanical endothelial cell dysfunction is discussed, emphasizing the impact of vessel wall material changes and endothelial cell responses to alterations in fluid shear stress. Inflammatory changes in OA and ASPVD are also explored, showcasing shared pathophysiological processes involving immune cell infiltration and pro-inflammatory cytokines. Additionally, the role of hypofibrinolysis in OA and ASPVD is discussed, highlighting similarities in elevations of the hypercoagulative and hypofibrinolytic factor, plasminogen activator inhibitor (PAI-1). The review suggests a provocative relationship among low-grade chronic inflammation, endothelial dysfunction, and hypofibrinolytic states in OA and ASPVD, warranting further investigation. In conclusion, this review provides an exploration of the possible associations between OA and ASPVD. While the ongoing study's findings and other reports are observational, they suggest shared pathophysiological processes and emphasize the need for further research to elucidate additional potentially correlative linkages between these conditions. Understanding common molecular pathways may pave a way for targeted interventions that address both OA and ASPVD.

A single intraarticular injection of a tranexamic acid-modified hyaluronic acid (HA/TXA) alleviates pain and reduces OA development in a murine model of monosodium iodoacetate-induced osteoarthritis

Rationale

Tranexamic acid (TXA) is a strong and specific plasminogen activator inhibitor with inhibitory effects on the matrix metalloproteases involved in the pathophysiology of osteoarthritis (OA) through targeting of the fibrinolysis pathway. In this study, we evaluated the analgesic and chondroprotective effects of a HA-tranexamic acid (HA/TXA) conjugate, compared to HA alone and placebo, in an animal model of knee OA.

Methods

Knee OA was induced in 15 C57 b l/6J mice by IA injection of 0.75 mg of Monosodium IodoAcetate (MIA). At day 28, the mice received 1 IA injection of 10 µL of saline (control-group), or of HA or of HA/TXA. Tactile sensitivity was assessed using von Frey filaments. Stimulations started at 1 g and increased until a response was obtained (up to 4 g). A response to the stimulus was counted if the animal withdrew its paw. If the animal responded to the 1 g stimulation, stimulation was reduced until the lack of response was observed (up to 0.2 g). At day 56, mice were euthanized for knee histological assessment. Cartilage degradation was assessed using the OARSI score. Statistical analysis was performed on GraphPad Prism 8.0.2 software. Kruskal-Wallis or Mann-Whitney tests were performed as appropriate.

Results

Just before treatment administration, no intergroup difference in paw withdrawal threshold was observed. Throughout the experiment animals given saline and HA had a lower paw withdrawal threshold than those treated with HA/TXA (p < 0.01). In the control group OARSI score was 5.5 ± 0.6. In HA and HA + TXA treated mice the OARSI score was 3.2 ± 0.8 and 3.1 ± 0.5 (p < 0.01) showing that both treatments were able to reduce OA progression.

Conclusion

In this animal model of MIA induced KOA, a single IA injection of a HA/TXA conjugate resulted in a greater efficacy on pain than both saline and HA. HA and HA/TXA exhibited chondroprotective effects compared to placebo.

Interleukin-37 Inhibits Interleukin-1β-Induced Articular Chondrocyte Apoptosis by Suppressing Reactive Oxygen Species

Objective: Chondrocyte apoptosis has been considered a crucial mechanism that is responsible for cartilage destruction in osteoarthritis (OA). The mechanism of interleukin-37 (IL-37) on chondrocyte apoptosis has not been clearly determined in the pathogenesis of OA. Here, we explored the role of IL-37 in the regulation of cellular apoptosis in rat chondrocytes stimulated by IL-1β. Methods: Rat chondrocytes were used in in vitro study, and were stimulated with IL-1β (10 ng/mL) and/or recombinant IL-37 (rIL-37; 100 ng/mL) after cytotoxicity assessments using these cytokines were conducted. After rIL-37 treatment of chondrocytes stimulated with IL-1β, the cell proliferation assay, apoptosis assays, including expression of mitochondrial apoptosis-related markers, flow cytometry analysis of annexin V-FITC/propidium iodide (PI), cell cycle analysis, and Hoechst 33342 staining, and reactive oxygen species (ROS) measurement were used. Results: IL-1β induced expression of inflammatory cytokines and triggered degradation of the extracellular matrix of rat chondrocytes, but this effect was significantly attenuated by rIL-37 treatment. Enhanced ROS generation following IL-1β stimulation was reduced in a dose-dependent manner after stimulation with rIL-37. IL-1β induced pro-apoptotic markers and suppressed anti-apoptotic markers in rat chondrocytes. Flow cytometry using annexin V-FITC/PI revealed that IL-1β increased the apoptosis rate of rat chondrocytes, and that this effect was markedly reversed by treatment with rIL-37. Conclusions: IL-37 potently attenuated IL-1β-mediated apoptosis of rat chondrocytes by blocking ROS production. This study suggests that IL-37 can serve as a novel anti-cytokine therapy in OA by blocking chondrocyte apoptosis.