The Potential of Gut Microbiota Metabolic Capability to Detect Drug Response in Rheumatoid Arthritis Patients

Methotrexate and Non-Surgical Periodontal Treatment Change the Oral-Gut Microbiota in Rheumatoid Arthritis: A Prospective Cohort Study

This study evaluated the changes in the composition of oral-gut microbiota in patients with rheumatoid arthritis (RA) caused by methotrexate (MTX) and non-surgical periodontal treatment (NSPT). Assessments were performed at baseline (T0), 6 months after MTX treatment (T1), and 45 days after NSPT (T2). The composition of the oral and gut microbiota was assessed by amplifying the V4 region of the 16S gene from subgingival plaques and stools. The results of the analysis of continuous variables were presented descriptively and non-parametric tests and Spearman's correlation were adopted. A total of 37 patients (27 with periodontitis) were evaluated at T0; 32 patients (24 with periodontitis) at T1; and 28 patients (17 with periodontitis) at T2. MTX tended to reduce the alpha diversity of the oral-gut microbiota, while NSPT appeared to increase the number of different species of oral microbiota. MTX and NSPT influenced beta diversity in the oral microbiota. The relative abundance of oral microbiota was directly influenced by periodontal status. MTX did not affect the periodontal condition but modified the correlations that varied from weak to moderate (p < 0.05) between clinical parameters and the microbiota. MTX and NSPT directly affected the composition and richness of the oral-gut microbiota. However, MTX did not influence periodontal parameters.

Advances in the implications of the gut microbiota on the treatment efficacy of disease-modifying anti-rheumatic drugs in rheumatoid arthritis

Alterations in the composition or function of the gut microbiota are associated with the etiology of human diseases. Drug-microbiota interactions can affect drug bioavailability, effectiveness, and toxicity through various routes. For instance, the direct effect of microbial enzymes on drugs can either boost or diminish their efficacy. Thus, considering its wide range of metabolic capabilities, the gut microbiota is a promising target for pharmacological modulation. Furthermore, drugs can alter the microbiota and the mechanisms by which they interact with their host. Individual variances in microbial profiles can also contribute to the different host responses to various drugs. However, the influence of interactions between the gut microbiota and drugs on treatment efficacy remains poorly elucidated. In this review, we will discuss the impact of microbiota dysbiosis in the pathogenesis of rheumatoid arthritis (RA), and we will attempt to elucidate the crosstalk between the gut microbiota and disease-modifying anti-rheumatic drugs (DMARDs), with an emphasis on how drug-microbiota interactions affect the treatment efficacy in RA. We speculate that improved knowledge of these critical interactions will facilitate the development of novel therapeutic options that use microbial markers for predicting or optimizing treatment outcomes.

Pharmacokinetics and bioequivalence evaluation of 2 oral formulations of methotrexate tablets in healthy Chinese volunteers under fasting and fed conditions

Methotrexate is an anti-metabolite drug that is frequently used for rheumatoid arthritis treatment. This study is aimed at evaluating the bioequivalence of 2 methotrexate tablets (2.5 mg) under fasting and fed conditions in healthy Chinese volunteers. A single-center, randomized, open-label, two-drug, two-period, crossover, single-dose trial protocol was designed. Fifty-two healthy Chinese participants were enrolled and randomly classified into fasting (n = 26) and fed (n = 26) group. Fifty of them participated in the whole trial course. Blood samples for pharmacokinetic (PK) analysis were collected 1 h before and up to 24 h after drug administration. To evaluate the bioequivalence of test and reference tablets, PK parameters including maximum plasma drug concentration (C_max), time to reach maximum concentration (T_max), area under the plasma concentration-time curve from time 0 to the last measurable concentration (AUC_0-t), and area under the plasma concentration-time curve from time 0 to infinity (AUC_0-∞) were calculated. Our data revealed that 90% CIs of geometric mean ratio of the test or reference drugs for C_max, AUC_0-t, and AUC_0-∞ fell within the acceptance range for bioequivalence (80-125%). Besides, it is worthwhile to mention that C_max and T_max in the fed group were lower than those in the fasting group. Interestingly, the absorption, measured by AUC, did not have significant difference in both groups. There were no suspected serious adverse reactions or serious adverse events over the entire trial. Our results demonstrated that the test and reference tablets were bioequivalent under fasting and fed conditions.

Role of Intestinal Dysbiosis and Nutrition in Rheumatoid Arthritis

Rheumatoid arthritis is a chronic systemic immune-mediated disease caused by genetic and environmental factors. It is often characterized by the generation of autoantibodies that lead to synovial inflammation and eventual multi-joint destruction. A growing number of studies have shown significant differences in the gut microbiota composition of rheumatoid arthritis (RA) patients compared to healthy controls. Environmental factors, and changes in diet and nutrition are thought to play a role in developing this dysbiosis. This review aims to summarize the current knowledge of intestinal dysbiosis, the role of nutritional factors, and its implications in the pathogenesis of rheumatoid arthritis and autoimmunity. The future direction focuses on developing microbiome manipulation therapeutics for RA disease management.