Search Results (1,718)

Osteoarthritis (OA) is a multifactorial joint disease traditionally characterized by cartilage degradation, while growing evidence underscores the critical role of synovial fibrosis in driving disease progression. The synovium exhibits pathological remodeling in OA, primarily due to the phenotypic transition of fibroblast-like synoviocytes (FLSs) into myofibroblasts. This fibroblast–myofibroblast transition (FMT) results in excessive deposition of extracellular matrix (ECM) and increased tissue stiffness and contractility, collectively contributing to chronic inflammation and fibrotic stiffening of the joint capsule. These fibrotic changes not only impair synovial function but also exacerbate cartilage degeneration, nociceptive sensitization, and joint dysfunction, thereby amplifying OA severity. Focusing on the frequently overlooked role of the FMT of synovial fibroblasts in OA, this review introduces the biological characteristics of FLSs and myofibroblasts and systematically examines the key molecular pathways implicated in OA-related FMT, including TGF-β, Wnt/β-catenin, YAP/TAZ, and inflammatory signaling cascades. It also discusses emerging therapeutic strategies targeting synovial fibrosis and FMT and considers their implications for the clinical management of OA. By highlighting recent advances and unresolved challenges, this review provides critical insights into the fibroblast–myofibroblast axis as a central contributor to OA progression and a promising therapeutic target for modifying disease trajectory. Full article

Osteoarthritis (OA) is the most prevalent form of joint arthritis, frequently associated with aging, mechanical wear, and inflammation. Our previous work demonstrated that cathelicidin-related antimicrobial peptide (Cramp) is upregulated in mouse OA cartilage, and that transient knockdown (KD) of Cramp in cultured chondrocytes decreases IL-1β-induced expression of matrix-degrading enzymes. The aim of this study was to determine the in vivo role of Cramp in OA pathogenesis using whole-body Cramp knockout (KO) mice. Normal skeletal development and growth plate morphology were assessed in E18.5d embryos and 2-week-old mice, respectively. Expression profiles of catabolic and anabolic genes were analyzed in primary chondrocytes derived from Cramp KO mice. OA in mouse knee joints was induced using intra-articular monosodium iodoacetate (MIA) injections or surgical destabilization of the medial meniscus (DMM). We observed that Cramp loss does not impact normal skeletal development. In contrast to our expectations, complete Cramp deficiency in chondrocytes failed to decrease catabolic gene expression upon IL-1β stimulation. Instead, genetic deletion of Cramp significantly worsened OA cartilage degradation in both MIA- and DMM-induced models. The detrimental phenotype observed in Cramp-deficient mice results from enhanced chondrocyte apoptosis. Therefore, even minimal Cramp expression appears essential for maintaining catabolic balance and preventing chondrocyte apoptosis in OA cartilage. Collectively, our data indicate that Cramp may exert multifaceted effects on OA pathogenesis by modulating catabolic pathways and apoptosis. Full article

Background and Objectives: Osteoarthritis (OA) is a degenerative joint disease involving inflammation, oxidative stress, and extracellular matrix (ECM) degradation, leading to cartilage damage and joint dysfunction. This study aimed to evaluate the chondroprotective effects of intra-articular hydrolyzed collagen in a rat model of knee OA using a dual-compartment biochemical and histological approach. Materials and Methods: Twenty male Sprague-Dawley rats underwent ACL transection to induce osteoarthritis and were randomly assigned to receive intra-articular hydrolyzed collagen or saline once weekly for three weeks. At six weeks, knee joints were evaluated histologically using the Mankin score. Synovial fluid and cartilage homogenates were analyzed via enzyme-linked immunosorbent assay (ELISA) for cytokines, cartilage degradation markers, and oxidative stress indicators. Results: The collagen-treated group demonstrated significantly lower Mankin scores. Levels of pro-inflammatory cytokines, interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), as well as cartilage degradation markers, matrix metalloproteinase-13 (MMP-13), C-terminal crosslinked telopeptide of type II collagen (CTX-II), and cartilage oligomeric matrix protein (COMP), were significantly reduced (p < 0.05). Additionally, oxidative stress indicators including inducible nitric oxide synthase (iNOS), total oxidant status (TOS), and oxidative stress index (OSI) were decreased, while total antioxidant status (TAS) was increased in both synovial fluid and cartilage homogenates (p < 0.05). Conclusions: Intra-articular hydrolyzed collagen reduced inflammation, oxidative stress, and extracellular matrix (ECM) degradation, indicating potential chondroprotective effects across both synovial and cartilage compartments. Full article

Osteoarthritis (OA) is the most common joint disorder worldwide. Autologous chondrocyte implantation (ACI) is an established treatment for articular cartilage defects of the knee, but its effectiveness in OA is still under investigation. In this study, we investigated the effects of a newly developed mammalian-derived collagen matrix, NC-Col, on the proliferation, migration, adhesion, and gene expression of human articular cartilage-derived chondrocytes from OA patients in vitro, using proliferation assays, wound healing assays, adhesion assays, RT-qPCR, and RNA sequencing, respectively. In addition, the effects of NC-Col were compared with three different commercially available collagen matrices, and the underlying molecular mechanisms through which NC-Col influences these cellular behaviours were explored. Our results showed that NC-Col, used as a coating matrix, enhances cell proliferation, maintains the phenotype, and upregulates Proteoglycan 4 (PRG4) in human articular cartilage-derived chondrocytes. Inhibition of the PI3K-Akt signalling pathway was found to be involved in some of these effects. In conclusion, our findings suggest that NC-Col collagen may offer new strategies for improving therapeutic outcomes in OA, particularly in the context of ACI. Full article

To investigate the involvement of gut–brain axis in musculoskeletal chronic pain in the elderly, this preclinical study aimed to compare osteoarthritis (OA) pain expression, cognitive function and gut microbiota composition in two aging rat strains (11–15 months). A validated surgically induced OA model was used in Sprague-Dawley (SD; n = 12), as standard group, and in LOU/C/Jall rats (LOU; n = 8), a healthy aging model. The OA pain response was assessed longitudinally (60 days) through quantitative sensory testing (mechanical sensitization and endogenous inhibitory control functionality), spatial memory, and gut microbiota. At sacrifice, joint structural alterations and spinal neuropeptides concentrations were quantified. After OA induction, higher mechanical hypersensitivity in LOU than in SD was also associated with higher endogenous inhibitory control (p < 0.05). Expression of pro-/anti-nociceptive spinal neuropeptides, cognitive function and joint alterations were similar in both groups. Gut microbiota composition was different (p < 0.001) and different taxa were associated with each strain (e.g., Akkermansia spp. with LOU vs. Lactobacillus spp. with SD). This study suggests healthy aging to be associated with more efficient endogenous pain control and expression of specific intestinal bacteria. This research questions the implication of the intestinal microbiota in aging and chronic pain control. Full article

Introduction: Osteoarthritis (OA), a leading cause of disability among the elderly, is characterized by progressive joint tissue destruction. Fucoidan, a sulfated polysaccharide with known anti-inflammatory and antioxidant properties, has been investigated for its potential to protect against interleukin-1 beta (IL-1β)-induced articular tissue damage. Methods: Human primary chondrocytes and synovial fibroblasts were pre-treated with 100 μg/mL fucoidan before stimulation with 1 ng/mL of IL-1β. The protective effects of fucoidan were assessed by measuring oxidative stress markers and catabolic enzyme levels. These in vitro findings were corroborated using a rat anterior cruciate ligament transection-induced OA model. To explore the underlying mechanisms, particularly the interaction between microRNAs (miRs) and heme oxygenase-1 (HO-1), five candidate miRs were identified in silico and experimentally validated. Luciferase reporter assays were used to confirm direct interactions. Results: Fucoidan exhibited protective effects against IL-1β-induced oxidative stress and catabolic processes in both chondrocytes and synovial fibroblasts, consistent with in vivo observations. Fucoidan treatment restored HO-1 expression while reducing inducible nitric oxide synthase and matrix metalloproteinase levels in IL-1β-stimulated cells. Notably, this study revealed that fucoidan modulates the miR-22/HO-1 pathway, a previously uncharacterized mechanism in OA. Specifically, miR-22 was upregulated by IL-1β and subsequently attenuated by fucoidan. Luciferase reporter assays confirmed a direct interaction between miR-22 and HO-1. Conclusion: The results demonstrate that fucoidan mitigates OA-related oxidative stress in chondrocytes and synovial fibroblasts through the novel modulation of the miR-22/HO-1 axis. The miR-22/HO-1 pathway represents a crucial therapeutic target for OA, and fucoidan may offer a promising therapeutic intervention. Full article

Autologous therapies are currently being studied to determine if they can modulate the course of knee osteoarthritis symptoms and/or disease progression. One potential therapeutic target is the polarization of pro-inflammatory M1 macrophages to pro-healing M2 macrophages. The autologous therapy, Autologous Protein Solution (APS), was incubated with donor-matched human peripheral-derived macrophages for 10 days. M1 pro-inflammatory macrophages were determined by the percentage of CD80+ and M2 pro-healing macrophages were determined by CD68+ and CD163+ by epifluorescent microscopy. To determine clinical effectiveness, an APS-specific minimal clinically important improvement (MCII) using an anchor-based method was calculated in a randomized controlled trial of APS (n = 46) and then applied to a real-world registry study (n = 78) to determine the percentage of pain responders. Compared to control media, APS statistically increased the percentage of M2 macrophages and decreased the percentage of M1 macrophages, while platelet-poor plasma had no effect on polarization. In the randomized controlled trial (RCT), the MCII at the 12-month follow-up visit was calculated as 2.0 points on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale and 7.5 points on the WOMAC function scale. Applying this MCII to the real-world registry data, 62.5% of patients met the MCII with an average of 4.7 ± 2.5 points of improvement in pain. Autologous therapies can influence macrophage polarization and have demonstrated clinical effectiveness in a real-world patient setting. Full article

Sleep is a vital physiological process for recovery and health. In people with knee osteoarthritis (OA), disrupted sleep is common and linked to worse clinical outcomes. Commercial sleep trackers provide an accessible option to monitor sleep in this population, but their accuracy for detecting sleep, wake, and sleep stages remains uncertain. This study compared nighttime sleep data from polysomnography (PSG) and Fitbit Sense in individuals with knee OA and insomnia. Data were collected from 53 participants (60.4% women, mean age 51 ± 8.2 years) over 62 nights using simultaneous PSG and Fitbit recording. Fitbit Sense showed high accuracy (85.76%) and sensitivity (95.95%) for detecting sleep but lower specificity (50.96%), indicating difficulty separating quiet wakefulness from sleep. Agreement with PSG was higher on nights with longer total sleep time, higher sleep efficiency, shorter sleep onset, and fewer awakenings, suggesting better performance when sleep is less fragmented. The device showed limited precision in classifying sleep stages, often misclassifying deep and REM sleep as light sleep. Despite these issues, Fitbit Sense may serve as a useful complementary tool for monitoring sleep duration, timing, and regularity in this population. However, sleep stage and fragmentation data should be interpreted cautiously in both clinical and research settings. Full article

Background/Objective: Understanding how chronic conditions such as knee osteoarthritis (OA) and chronic obstructive pulmonary disease (COPD) influence long-term physical activity (PA) is essential for developing condition-specific rehabilitation strategies. This study aimed to examine whether baseline diagnoses of knee OA and COPD are independently associated with the trajectories of PA decline over five years in U.S. adults, informed by the disablement process model. Methods: We analyzed data from 855 adults aged ≥45 years enrolled in the Osteoarthritis Initiative (OAI). The participants were categorized into three baseline groups, control (n = 122), knee OA (n = 646), and COPD (n = 87), based on self-reports and prior clinical assessments. PA was measured annually for five years using the Physical Activity Scale for the Elderly (PASE). General linear mixed models assessed changes in PA over time, adjusting for demographic, behavioral, and clinical covariates. Results: Compared to the controls, participants with knee OA had a significant decline in PA over time (β = −6.62; 95% CI: −15.4 to −2.19; p = 0.014). Those with COPD experienced an even greater decline compared to the knee OA group (β = −11.2; 95% CI: −21.7 to −0.67; p = 0.037). These associations persisted after adjusting for age, sex, body mass index, comorbidities, and smoking. Conclusions: Baseline knee OA and COPD were independently associated with long-term reductions in PA. These findings underscore the importance of early, tailored rehabilitation strategies, particularly pulmonary rehabilitation, in preserving functional independence among older adults with chronic conditions. Full article

Osteoarthritis (OA) is a chronic progressive joint disease characterized by cartilage degradation, subchondral bone remodeling, and synovial inflammation. This complex disorder arises from the interplay between mechanical stress and inflammatory processes, which is mediated by interconnected molecular signaling pathways. This review explores the dual roles of inflammatory and mechanical signaling in OA pathogenesis, focusing on crucial pathways such as NF-kB, JAK/STAT, and MAPK in inflammation, as well as Wnt/β-catenin, Integrin-FAK, and Hippo-YAP/TAZ in mechanotransduction. The interplay between these pathways highlights a vicious cycle wherein mechanical stress exacerbates inflammation, and inflammation weakens cartilage, increasing its vulnerability to mechanical damage. Additionally, we discuss emerging therapeutic strategies targeting these pathways, including inhibitors of cartilage-degrading enzymes, anti-inflammatory biologics, cell-based regenerative approaches, and non-pharmacological mechanical interventions. By dissecting the molecular mechanisms underlying OA, this review aims to provide insights into novel interventions that address both inflammatory and mechanical components of the disease, paving the way for precision medicine in OA management. Full article

Proper joint function has a significant impact on people’s quality of life. Joints are the point of connection between two or more bones and consist of at least three elements: joint surfaces, the joint capsule, and the joint cavity. Joint diseases are a serious social problem. Risk factors for the development of these diseases include overweight and obesity, gender, and intestinal microbiome disorders. Another factor that is considered to influence joint diseases is trace elements. Under normal conditions, elements such as iron (Fe), copper (Cu), cobalt (Co), iodine (I), manganese (Mn), zinc (Zn), silver (Ag), cadmium (Cd), mercury (Hg), lead (Pb), nickel (Ni) selenium (Se), boron (B), and silicon (Si) are part of enzymes involved in reactions that determine the proper functioning of cells, regulate redox metabolism, and determine the maturation of cells that build joint components. However, when the normal concentration of the above-mentioned elements is disturbed and toxic elements are present, dangerous joint diseases can develop. In this article, we focus on the role of trace elements in joint function. We describe the molecular mechanisms that explain their interaction with chondrocytes, osteocytes, osteoblasts, osteoclasts, and synoviocytes, as well as their proliferation, apoptosis, and extracellular matrix synthesis. We also focus on the role of these trace elements in the pathogenesis of joint diseases: rheumatoid arthritis (RA), osteoarthritis (OA), psoriatic arthritis (PsA), ankylosing spondylitis (AS), and systemic lupus erythematosus (SLE). We describe the roles of increased or decreased concentrations of individual elements in the pathogenesis and development of joint diseases and their impact on inflammation and disease progression, referring to molecular mechanisms. We also discuss their potential application in the treatment of joint diseases. Full article

Osteoarthritis (OA) remains a major contributor to pain and disability; however, the current management is largely reactive, focusing on symptoms rather than preventing irreversible cartilage loss. This review first examines the mechanistic foundations for pharmacological chondroprotection—illustrating how conventional agents, such as glucosamine sulfate and chondroitin sulfate, can potentially restore extracellular matrix (ECM) components, may attenuate catabolic enzyme activity, and might enhance joint lubrication—and explores the delivery challenges posed by avascular cartilage and synovial diffusion barriers. Subsequently, a practical “What–How–When” framework is introduced to guide community pharmacists in risk screening, DMOAD selection, chronotherapeutic dosing, safety monitoring, and lifestyle integration, as exemplified by the CHONDROMOVING infographic brochure designed for diverse health literacy levels. Building on these strategies, the P4–4P Chondroprotection Framework is proposed, integrating predictive risk profiling (physicians), preventive pharmacokinetic and chronotherapy optimization (pharmacists), personalized biomechanical interventions (physiotherapists), and participatory self-management (patients) into a unified, feedback-driven OA care model. To translate this framework into routine practice, I recommend the development of DMOAD-specific clinical guidelines, incorporation of chondroprotective chronotherapy and interprofessional collaboration into health-professional curricula, and establishment of multidisciplinary OA management pathways—supported by appropriate reimbursement structures, to support preventive, team-based management, and prioritization of large-scale randomized trials and real-world evidence studies to validate the long-term structural, functional, and quality of life benefits of synchronized DMOAD and exercise-timed interventions. This comprehensive, precision-driven paradigm aims to shift OA care from reactive palliation to true disease modification, preserving cartilage integrity and improving the quality of life for millions worldwide. Full article

Background: Residual deficits after early treatment of developmental dysplasia of the hip (DDH) using osteotomy often led to asymmetrical gait deviations with increased repetitive rates of ground reaction force (GRF) in both hips, resulting in a higher risk of early osteoarthritis. This study investigated lower limb inter-joint coordination and swing foot control during level walking in adolescents with early-treated unilateral DDH. Methods: Eleven female adolescents treated early for DDH using Pemberton osteotomy were compared with 11 age-matched healthy controls. The joint angles and angular velocities of the hip, knee, and ankle were measured, and the corresponding phase angles and continuous relative phase (CRP) for hip–knee and knee–ankle coordination were obtained. The variability of inter-joint coordination was quantified using the deviation phase values obtained as the time-averaged standard deviations of the CRP curves over multiple trials. Results: The DDH group exhibited a flexed posture with increased variability in knee–ankle coordination of the affected limb throughout the gait cycle compared to the control group. In contrast, the unaffected limb compensated for the kinematic alterations of the affected limb with reduced peak angular velocities but increased knee–ankle CRP over double-limb support and trajectory variability over the swing phase. Conclusions: The identified changes in inter-joint coordination in adolescents with early treated DDH provide a plausible explanation for the previously reported increased GRF loading rates in the unaffected limb, a risk factor of premature OA. Full article

Cartilage degradation is a key feature of osteoarthritis (OA), a joint disease that significantly impacts the quality of life of the elderly population. While advanced age is recognized as one of the major risk factors for OA, the underlying mechanisms are not fully understood. Research involving cartilage from aged animals has improved our understanding of the changes associated with aging. However, studies with aged animals can be time-consuming and costly. In this study, we investigate the use of human sera from older donors as a stressor to induce aging-like changes in cultured human chondrocytes. First, we assess the expression levels of markers related to chondrogenesis, hypertrophy, fibrosis, and inflammation in human chondrocytes treated with sera from younger or older human donors. Next, we evaluate the regenerative potential of these sera-treated chondrocytes by stimulating them with the anabolic factor transforming growth factor (TGF)-β3. The results show that treatment with sera from older donors induced an aging-like phenotype in chondrocytes and impaired their ability to generate new cartilage. These findings provide insight into the role of systemic factors (serum) in cartilage aging and offer a novel in vitro model for studying age-related changes in chondrocytes. Full article

Obesity, characterized by excessive or abnormal accumulation of body fat, is associated with a range of metabolic and inflammatory diseases, including osteoarthritis (OA). In obese individuals, adipose tissue expansion—via adipocyte hypertrophy or hyperplasia—is accompanied by altered secretion of adipokines such as leptin and adiponectin, which play significant roles in immune modulation, metabolism, and skeletal homeostasis. Leptin, acting through the hypothalamus, regulates the sympathetic nervous system and modulates hormonal axes, influencing bone metabolism and cartilage integrity. Elevated leptin concentrations in the synovial fluid, and the presence of its receptors on cartilage surfaces, suggest its direct role in cartilage degradation and OA progression. Conversely, adiponectin exerts anti-inflammatory effects, modulates osteoblast and macrophage activity, and appears to have a protective function in joint metabolism. These findings underscore the complex interplay between the adipose tissue, adipokines, and the osteochondral unit, highlighting the importance of their balance in maintaining joint health. Full article