Usefulness of daily folic acid supplementation during methotrexate treatment of Japanese patients with rheumatoid arthritis

Real-world Methotrexate Use in a Prospective Cohort of Paediatric Patients with Plaque Psoriasis: Effectiveness, Adverse Events and Folic Acid Regimen

In paediatric psoriasis, few studies have evaluated methotrexate effectiveness, adverse events and folic acid regimen. Therefore this study prospectively assessed methotrexate adverse events and effectiveness in paediatric patients with psoriasis in a real-world setting. Furthermore, gastrointestinal adverse events and methotrexate effectiveness were compared between folic acid regimens (5 mg once weekly vs 1 mg 6 times weekly). Data for paediatric patients with psoriasis treated with methotrexate from September 2008 to October 2020 were extracted from Child-CAPTURE, a prospective, daily clinical practice registry. Effectiveness was determined by Psoriasis Area and Severity Index (PASI). Comparison of persistent gastrointestinal adverse events between folic acid regimens were assessed through Kaplan–Meier analysis. A total of 105 paediatric patients with plaque psoriasis (41.0% male, mean age 14.1 years) were included. At week 24 and 48, an absolute PASI ≤ 2.0 was achieved by approximately one-third of all patients. During follow-up, 46.7% reported ≥ 1 persistent adverse events. After 1 and 2 years, approximately one-quarter of patients achieved a PASI ≤ 2.0 without persistent adverse events. Although non-significant, a possible trend towards lower occurrence of gastrointestinal adverse events was found for folic acid 1 mg 6 times weekly (p = 0.196), with similar effectiveness between folic acid regimens. These findings show that a subgroup of paediatric patients with psoriasis responded well to methotrexate treatment without considerable side-effects during a 2-year follow-up.

Application and pharmacological mechanism of methotrexate in rheumatoid arthritis

Methotrexate (MTX) has been used for the treatment of rheumatoid arthritis (RA) for about forty years and to date MTX remains the part of global standard of treatment for RA. The efficacy of MTX in RA is the result of multiple mechanisms of action. In order to summarize the possible pharmacological mechanisms of MTX in the treatment of RA, this review will elaborate on folate antagonism, promotion of adenosine accumulation, regulation of inflammatory signaling pathways, bone protection and maintenance of immune system function.

Properties and reactivity of the folic acid and folate photoproduct 6-formylpterin

Folates (vitamin B9) are essential components of our diet and our gut microbiota. They are omnipresent in our cells and blood. Folates are necessary for DNA synthesis, methylation, and other vital bioprocesses. Folic acid (FA), as the synthetic form of folates, is largely found in supplements and fortified foods. FA and folate drugs are also extensively used as therapeutics. Therefore, we are continuously exposed to the pterin derivatives, and their photo-degradation products, such as 6-formylpterin (6-FPT) and pterin-6-carboxylic acid. During ultraviolet radiation, these two photolytic products generate reactive oxygen species (ROS) responsible for the cellular oxidative stress. 6-FPT can exhibit variable pro/anti-oxidative roles depending on the cell type and its environment (acting as a cell protector in normal cells, or as an enhancer of drug-induced cell death in cancer cells). The ROS-modulating capacity of 6-FPT is well-known, whereas its intrinsic reactivity has been much less investigated. Here, we have reviewed the properties of 6-FPT and highlighted its capacity to form covalent adducts with the ROS-scavenging drug edaravone (used to treat stroke and amyotrophic lateral sclerosis) as well as its implication in immune surveillance. 6-FPT and its analogue acetyl-6-FPT function as small molecule antigens, recognized by the major histocompatibility complex-related class I-like molecule, MR1, for presentation to mucosal-associated invariant T (MAIT) cells. As modulators of the MR1/MAIT machinery, 6-FPT derivatives could play a significant immuno-regulatory role in different diseases. This brief review shed light on the multiple properties and cellular activities of 6-FPT, well beyond its primary ROS-generating activity.