AB0061 ALTERATIONS OF XANTHINE OXIDOREDUCTASE ACTIVITY IN RED BLOOD CELLS AFTER GLUCOCORTICOID TREATMENT IN RHEUMATOID ARTHRITIS
Authors: E. Mozgovaya, S. Bedina, A. Trofimenko, M. Mamus, S. Spitsina, I. Zborovskaya
Journal: Annals of the Rheumatic Diseases (2021)

Background: According to modern concepts, rheumatoid arthritis (RA) refers to severe autoimmune rheumatic diseases. The activation of free radical oxidation processes is essential in the development of this disease [1]. Xanthine oxidoreductase is a significant reactive oxygen species source [2]. Despite the great advances in the treatment of rheumatoid arthritis (RA) associated with the introduction of innovative drugs and especially the improvement of the strategy for their use into clinical practice, glucocorticoids still remain an important component of RA pharmacotherapy in actual clinical practice. Objectives: to evaluate the changes in activities of xanthine oxidoreductase interconvertible forms (xanthine oxidase, ЕС 1.17.3.2 and xanthine dehydrogenase, ЕС 1.17.1.4) in lysed red blood cells of RA patients in relation with glucocorticoid treatment. Methods: 47 RA patients with verified RA and 30 healthy controls were enrolled in the study. The diagnosis was verified using the 2010 ACR/EULAR criteria 2010. All patients have moderate DAS28 scores. RA patients were randomized into 2 groups comparable in gender, age and the principal clinical manifestations. Methylprednisolone (Metipred, Orion Corp.), average dose 30 mg/day, and betamethasone (Diprospan, Schering-Plough), single dose7 mg, were administered intramuscularly in the respective groups. Хanthine oxidase (XO) and xanthine dehydrogenase (XDG) activities were measured in lysed red blood cells by spectrophotometric method as previously described [3]. The changes of these enzymes activities were studied in RA patients before and after the injection of glucocorticoids. Statistical comparison tests were selected in according to common guidelines, differences were considered significant when p&lt;0.05. Central tendencies were expressed as means±SEM. Results: Mean age of patients in methylprednisolone group was 41.8±1.05 years, and mean RA duration (± SEM) was 7.9±0.21 years. Mean age of patients in diprospan group was 40.9±1.07 years, and mean RA duration was 8.0±0.33 years. Significant decreases of XO activity and increase of XDG activity were observed in lysed red blood cells of RA patients just after the injection of each glucocorticoid drug. Changes of the enzymatic activities in lysed red blood cells were more pronounced in methylprednisolone group. However enzymatic activity did not reach the level of healthy controls. As described previously, decreased XO activity and increased XDG activity were observed in plasma of RA patients just after the injection of the average therapeutic doses of glucocorticoids, as well as in lysed lymphocytes just after the injection of methylprednisolone [4]. Conclusion: Treatment with methylprednisolone and betamethasone can affect the balance of XO/XDG activity and increase the antioxidant potential of the blood. This effect can exert beneficial influence on autoimmune inflammation in RA. References: [1]Mateen S., et al. Increased reactive oxygen species formation and oxidative stress in rheumatoid arthritis. PLoS ONE 2016;11(4):e0152925. [2]Çimen M.Y., et al. Oxidant/antioxidant status of the erythrocytes from patients with rheumatoid arthritis. Clin Rheumatol 2000;19(4):275-277. [3]Zborovskaya I.A., et al. Influence of analgetics on plasma and lymphocytic activity of the purine metabolism enzymes in rheumatoid arthritis patients. Russian Journal of Pain 2018;3:47. [4]Mozgovaya E.E., et al. Xanthinoxidase and xanthine dehydrogenase activities in rheumatoid arthritis after glucocorticoid treatment. Osteoporosis International 2019;30(2):S433-434. Disclosure of Interests: None declared