Adenosine Deaminase Gene Polymorphism and Baseline Serum Level of Adenosine Deaminase as a Biomarker of Response to Methotrexate in Rheumatoid Arthritis

Biomarkers to Predict DMARDs Efficacy and Adverse Effect in Rheumatoid Arthritis

Rheumatoid arthritis (RA), one of the most common immune system diseases, mainly affects middle-aged and elderly individuals and has a serious impact on the quality of life of patients. Pain and disability caused by RA are significant symptoms negatively affecting patients, and they are especially seen when inappropriate treatment is administered. Effective therapeutic strategies have evolved over the past few decades, with many new disease-modifying antirheumatic drugs (DMARDs) being used in the clinic. Owing to the breakthrough in the treatment of RA, the symptoms of patients who could not be treated effectively in the past few years have been relieved. However, some patients complain about symptoms that have not been reported, implying that there are still some limitations in the RA treatment and evaluation system. In recent years, biomarkers, an effective means of diagnosing and evaluating the condition of patients with RA, have gradually been used in clinical practice to evaluate the therapeutic effect of RA, which is constantly being improved for accurate application of treatment in patients with RA. In this article, we summarize a series of biomarkers that may be helpful in evaluating the therapeutic effect and improving the efficiency of clinical treatment for RA. These efforts may also encourage researchers to devote more time and resources to the study and application of biomarkers, resulting in a new evaluation system that will reduce the inappropriate use of DMARDs, as well as patients’ physical pain and financial burden.

Quercetin mitigates rheumatoid arthritis by inhibiting adenosine deaminase in rats

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterized by synovial proliferation and bone destruction. Adenosine deaminase (ADA) is a key inflammatory enzyme that increases joint stiffness and pain in RA. In this study, we evaluated the in-silico, and in vivo inhibitory effect of quercetin isolated from Egyptian Fenugreek on ADA enzyme activity. We also determined the combinatorial effect of quercetin on methotrexate mediated anti-inflammatory efficacy and toxicity. In-silico molecular docking was conducted and confirmed in an in vivo RA rat model. The results showed that the inhibition constant of quercetin on joint ADA by docking and in-vitro was 61.9 and 55.5 mM, respectively. Therefore, quercetin exhibits anti-inflammatory effect in a rat RA model as evidenced by reducing the specific activity of ADA in joint tissues, lower jaw volume, enhance body weight, downregulate ADA gene expression, reduce levels of RA cytokines interleukin-1^β, interleukin-6, tumor necrosis factor-α, also, rheumatoid factor, C-reactive protein, and anti-cyclic citrullinated peptide RA biomarker levels. These findings demonstrate that the purified quercetin has a promising anti-inflammatory effect against RA disease through its inhibitory effects on the ADA enzyme. Furthermore, isolated quercetin improved the anti-inflammatory efficacy of methotrexate, reduced its toxic effects by increasing antioxidant enzymes and reducing oxidative stress.