Relationship between frailty and methotrexate discontinuation due to adverse events in rheumatoid arthritis patients.

INTRODUCTION: Methotrexate (MTX) is an anchor drug in the treatment of rheumatoid arthritis (RA). Frailty is the intermediate condition between being healthy and disabled, and can lead to negative health outcomes. Adverse events (AEs) due to RA drugs are expected to be higher in frail patients. The present study aimed to investigate the relationship between frailty and MTX discontinuation due to AEs in RA patients. METHODS: Of 538 RA patients who visited us between June and August 2020 as part of the retrospective T-FLAG study, 323 used MTX. After 2 years of follow-up, we investigated AEs leading to MTX discontinuation. Frailty was defined as a Kihon Checklist (KCL) score ≥ 8. Cox proportional hazards regression analysis was performed to identify factors associated with MTX discontinuation due to AEs. RESULTS: Of the 323 RA patients (251 women, 77.7%) who used MTX, 24 (7.4%) discontinued MTX due to AEs during the 2-year follow-up period. Mean ages in the MTX continuation/discontinuation groups were 64.5 ± 13.9/68.5 ± 11.7 years (p = 0.169), Clinical Disease Activity Index was 5.6 ± 7.3/6.2 ± 6.0 (p = 0.695); KCL was 5.9 ± 4.1/9.0 ± 4.9 points (p < 0.001); and the proportion of frailty was 31.8%/58.3% (p = 0.012). MTX discontinuation due to AEs was significantly associated with frailty (hazard ratio 2.34, 95% confidence interval 1.02-5.37) even after adjusting for age and diabetes mellitus. AEs included liver dysfunction (25.0%), pneumonia (20.8%), and renal dysfunction (12.5%). CONCLUSIONS: Because frailty is a significant factor contributing to MTX discontinuation due to AEs, the latter should be carefully monitored in frail RA patients who use MTX. Key Points • Of the 323 rheumatoid arthritis (RA) patients (251 women, 77.7%) who used methotrexate (MTX), 24 (7.4%) discontinued MTX due to adverse events (AEs) during the 2-year follow-up period. • MTX discontinuation due to AEs was significantly associated with frailty (hazard ratio 2.34, 95% confidence interval 1.02-5.37) even after adjusting for age and diabetes mellitus, and neither the MTX dose, folic acid supplementation, nor GC co-therapy were factors in MTX discontinuation. • Frailty is a predominant factor in MTX discontinuation among established, long-term pretreated RA patients, and the occurrence of AEs due to MTX should be carefully monitored when frail RA patients use MTX.

Hyaluronan suppresses enhanced cathepsin K expression via activation of NF-κB with mechanical stress loading in a human chondrocytic HCS-2/8 cells.

Cathepsin K is a protease known to be involved in not only bone remodeling and resorption, but also articular cartilage degradation that leads to osteoarthritis (OA). Hyaluronan (HA) plays a pivotal role in maintaining homeostasis within articular chondrocytes. Intra-articular supplementation of high molecular weight hyaluronan (HMW-HA) has been widely used in OA treatment. However, its prospective mechanism of action is still unclear. In this study, we examined the suppressive effect of HA on enhanced cathepsin K expression induced by mechanical stress loading. A human chondrocytic HCS-2/8 cells were cultured in silicon chambers and subjected to cyclic tensile stress (CTS) loading. CTS loading significantly increased messenger ribonucleic acid and protein expression of cathepsin K, which appeared to be suppressed by pre-treatment with HMW-HA. Activation of nuclear factor-kappa B (NF-κB) was induced by CTS loading, and suppressed by pre-treatment with HMW-HA. Helenalin, a chemical inhibitor of NF-κB, clearly suppressed the enhanced expression of cathepsin K, as well as NF-κB activation induced by CTS loading. The suppressive effect of HMW-HA on enhanced cathepsin K expression via NF-κB inhibition impacts the effectiveness of HMW-HA in OA treatment. Our findings provide new evidence supporting the biological effectiveness of intra-articular HMW-HA injections for treatment of OA.

Suppression of murine osteoarthritis by 4-methylumbelliferone.

Using in vitro models, we previously reported that 4-methylumbelliferone (4-MU) blocked many of the pro-catabolic features of activated chondrocytes. 4-MU also blocked safranin O loss from human cartilage explants exposed to interleukin 1ß (IL1ß) in vitro. However, the mechanism for this chondroprotective effect was independent of the action of 4-MU as a hyaluronan (HA) inhibitor. Interestingly, overexpression of HA synthase 2 (HAS2) also blocked the same pro-catabolic features of activated chondrocytes as 4-MU via a mechanism independent of extracellular HA accumulation. Data suggest that altering UDP-sugars may be behind these changes in chondrocyte metabolism. However, all of our previous experiments with 4-MU or HAS2 overexpression were performed in vitro. The purpose of this study was to confirm whether 4-MU was effective at limiting the effects of osteoarthritis (OA) on articular cartilage in vivo. The progression of OA was evaluated after destabilization of the medial meniscus (DMM) surgery on C57BL/6 mice in the presence or absence of 4-MU-containing chow. Mice fed 4-MU after DMM surgery exhibited significant suppression of OA starting from an early stage in vivo. Mice fed 4-MU exhibited lower OARSI scores after DMM; reduced osteophyte formation and reduced MMP3 and MMP13 immunostaining. 4-MU also exerted pronounced chondroprotective effects on murine joint cartilage exposed to IL1ß in vitro and, blocked IL1ß-enhanced lactate production in cartilage explants. Therefore, 4-MU is effective at significantly reducing the loss of proteoglycan and reducing MMP production both in vitro and in vivo as well as cartilage damage and osteophyte formation in vivo after DMM. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. 38:1122-1131, 2020.