Evaluation of Cartilage Integrity Following Administration of Oral and Intraarticular Nifedipine in a Murine Model of Osteoarthritis

TRIM8 enhances chondrocyte ferroptosis by inhibiting YTHDF2-m6A mediated SREBF2 mRNA degradation to promote OA progression

Chondrocyte ferroptosis plays a crucial role in osteoarthritis (OA) progression. Our previous study demonstrated that TRIM8 knockdown alleviated IL-1β-induced chondrocyte injury. However, the involvement of TRIM8 in regulating OA progression through ferroptosis remains unclear. In this study, human OA and normal cartilage samples were collected to examine ferroptosis and TRIM8 expression. We found that both ferroptosis markers and TRIM8 protein levels were elevated in OA cartilage compared to controls. An OA cell model was established by stimulating chondrocytes with IL-1β. TRIM8 knockdown mitigated IL-1β-induced ferroptosis, extracellular matrix (ECM) degradation, and inflammation in chondrocytes. Mechanistically, TRIM8 facilitated the ubiquitylation of YTHDF2 via its RING domain, promoting YTHDF2 protein degradation. This inhibited YTHDF2-m6A-induced SREBF2 mRNA degradation, thereby upregulating SREBF2 expression and enhancing chondrocyte ferroptosis. As expected, SREBF2 overexpression reversed the protective effect of TRIM8 silencing on IL-1β-induced chondrocyte injury. An OA mouse model was established using destabilized medial meniscus surgery, and TRIM8 deficiency alleviated cartilage degradation and synovial inflammation. In conclusion, TRIM8 promotes chondrocyte ferroptosis by suppressing YTHDF2-m6A mediated SREBF2 mRNA degradation, thereby accelerating OA progression.

A Cross-Sectional Study of Factors Predicting the Duration of the Efficacy of Viscosupplementation in Knee Osteoarthritis

Background: An advanced radiological stage and obesity are predictive of poorer and shorter responses to viscosupplementation in patients with knee osteoarthritis (OA). Very little is known regarding the impact of other factors such as sport practice, comorbidities, or anatomical features of OA. Methods: This study aimed to investigate patients' and OA characteristics associated with the duration of the effectiveness (DE) of viscosupplementation in patients with knee OA. It was a cross-sectional, single-centre clinical trial in patients with knee OA treated with intra-articular (IA) hyaluronic acid (HA) injection(s) within the previous 3 years. The investigators collected data regarding demographic and radiographic features (Kellgren-Lawrence grade and involved knee compartments), dosing regimen (single or repeat injections), the presence and volume of joint effusion, previous or concomitant IA corticosteroid injection, the number of previous viscosupplementations, and comorbidities. Patients completed a questionnaire including the self-assessment of DE (the number of weeks during which viscosupplementation was effective on symptoms), the activity level (sedentary, active, or athletic), and the level of sport activity (light, moderate, or intensive). Predictors of the DE were studied in bivariate and multivariate analyses. Results: In total, 105 patients (149 knees) were analysed (62% women, mean age 66.1 ± 13.2 years, mean BMI 27.5 ± 7.5 kg/m2). The mean DE was 48.2 ± 24.8 weeks. In bivariate analysis, the predictors of a shorter DE were BMI > 27.5 kg/m2, more than three previous viscosupplementations, Kellgren-Lawrence grade 4, sedentary patients, and multicompartmental involvement. In the multivariate analysis, four independent factors remained associated with a shorter DE: BMI > 27.5 kg/m2, multicompartmental knee involvement, number of viscosupplementations >3, and sedentary lifestyle. A statistically significant association between a longer DE and arterial hypertension was found, suggesting a beneficial effect of certain antihypertensive medications. Conclusions: This study confirms that being overweight significantly reduces the duration of the effectiveness of viscosupplementation. It also shows that viscosupplementation is more lastingly effective in unicompartmental OA and among active or athletic patients. The duration of effectiveness decreases when the treatment is repeated more than three times.