weeks. The serum level of elastase remained unchanged. The administration of lactoferrin in the chronic phase of adjuvant arthritis resulted in a steady suppression of the inflammatory process (decreased hind paws swelling and local temperature, white blood cell count and erythrocyte sedimentation rate, an increase in weight gaining and a decrease in serum elastase level), which lasted until the end of experiment (day 50). This effect was achieved with lower doses of the drug (9 mg/kg), though its strength was dose-dependent. The maximal suppression of adjuvant arthritis was obtained with the repeated injections of lactoferrin (5 injections every other day with total dose of 60 mg/kg) in the chronic phase of adjuvant arthritis (days 23-31). In these rats the serum concentration of elastase was reduced down to normal level and the rate of generalisation was less than 8%. Conclusion Lactoferrin is a potent anti-inflammatory agent effective in treatment of adjuvant arthritis in rats. The maximal suppression of the inflammatory process is obtained in the chronic phase of adjuvant arthritis.

Background:The oxidative-related enzymes are involved in the pathogenesis of various stages of systemic sclerosis (SSc). SSc is a chronic autoimmune disorder that is intimately associated with vascular damage and therefore with chronic perfusion/reperfusion and oxidative organ injury. Mesenchymal cell activation in SSc is now also considered to be mediated primarily through oxidative burst. Regulation of oxidative stress by specific enzymes including several purine metabolism enzymes is likely to play an important role in SSc progression.Objectives:to characterize interrelationships among circulating xanthine oxidase (XO), xanthine dehydrogenase (XDH), superoxide dismutase (SOD) activities and SSc activity.Methods:The study was performed according to bioethical standards. 51 patients with verified SSc and 30 healthy controls were included in the study. The diagnosis was verified according to ACR/EULAR 2013 criteria. We assessed SSc activity in compliance with the original activity scale that is commonly used in Russia [Guseva N.G., 1993] and by the 2001 European Scleroderma Study Group Activity Index. XO (EC 1.17.3.2), XDH (EC 1.17.1.4), and SOD (EC 1.15.1.1) plasma activities were measured using spectrophotometric techniques as previously described [Dubinina E.E., 1986; Karpova O.V., 2006]. Results are expressed as mean±SD. The Mann-Whitney U test and Spearman’s correlation coefficient were used for statistical analysis.Results:Mean age of patients was 42.8±1.3 years, mean SSc duration was 7.9±0.7 years. Mean enzymatic activities in normal controls were 3.43±0.56 nmol/ml min (for XO), 5.19±0.71 nmol/ml min (for XDH), and 5.40±1.03 units (for SOD). The respective enzymatic activities in SSc group were 3.91±0.62 nmol/ml min, 7.10±0.71 nmol/ml min, and 7.10±2.19 units. All these mean activities were significantly higher in SSc patients comparing to healthy individuals (p<0.001). XO and XDH activities positively correlated with SSc activity (r=0.499, p<0.001, and r=0.741, p<0.001, respectively). The opposite but weaker trend was observed for SOD activity and SSc disease activity (r=-0.190, p=0.188).Conclusion:SSc is characterized by an increase in the intensity of oxidative and antioxidant processes, more pronounced in high disease activity. A close relationship between function of prooxidant/antioxidant enzymes and some of the key SSc pathogenetic mechanisms, especially vascular disease and fibroblast activation, is widely considered. Overall increase of oxidative stress in patients with higher disease activity, as well as depletion of antioxidant capacity can be also linked with disturbance of purine metabolism through XO and XDH modulation. Pathogenetic influence of this imbalance can also be mediated through initial phase of neutrophil extracellular traps (NETs) formation, an eventual source of nucleoprotein containing autoepitopes.Disclosure of Interests:None declared

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<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

Background:Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by the presence of rheumatoid factor (RF) and anticitrulline autoantibodies. Recent evidences suggest that impairment of neutrophil extracellular traps (NETs) could exert substantial influence on RA pathogenesis. The production of NETs depends heavily on the ROS generation. One of its mechanisms is xanthine oxidoreductase (XOR) mediated degradation of purine metabolites. Analysis of pro-oxidant activity of the enzymatic complex XOR and its constituents, xanthine oxidase (XO) and xanthine dehydrogenase (XDG), is an issue of considerable interest in this context.Objectives:Evaluation of XO and XDG activities in RF-positive and RF-negative RA using both plasma and lysed lymphocyte samples.Methods:The research was carried out in agreement with the WMA Declaration of Helsinki principles. Diagnosis of RA had been verified using ACR/EULAR 2010 criteria. Enzymatic activities in plasma and lymphocytes were measured spectrophotometrically and expressed as nmol/min/ml. Enzymatic activities in lymphocytes were also normalized to 1×107 cells/ml. Statististical tests were selected in line with common guidelines. Differences were considered significant when p<0.05. Reference ranges were calculated as means ±2SD.Results:75 adult RA patients (52 females and 23 males, mean age 43.9±0.97 years, mean disease duration 8.5±0.3 years) from the rheumatology unit of Volgograd Clinical Emergency Hospital #25 as well as 35 healthy controls were included in the study. RF-positive RA and RF-negative RA were observed in 49 (65.3%) and 26 (34.7%) patients, respectively. Reference ranges for plasma and lymphocyte XO activities were 2.60-3.96 and 14.2-27.8 nmol/min/ml, respectively. Similar ranges for XDG activities were 4.49-5.93 and 22.5-40.7 nmol/min/ml, respectively. Enzymatic profile of RA patients is characterized by significantly increased XO activity in plasma and decreased XO and XDG activities in lymphocytes (р<0.001). XO activity is increased (p<0.001), XDG activity is decreased (p<0.001) in blood plasma of patients with RF-negative RA, while the activity of both enzymes is decreased in lymphocytes (p<0.001). XO activity (p<0.001) and XDG activity (p<0.05) is increased in blood plasma, XO activity and XDG activity are decreased (p<0.001) in lymphocytes of patients with RF-positive RA. Plasma XO and XDG activities are also higher, and lymphocyte XO and XDG activities are lower in patients with RF-positive RA than in patients with RF-negative RA (р<0.001).Conclusion:Our study revealed the relationship between enzyme parameters and rheumatoid factor presence. More pronounced changes in the enzyme activities were observed in patients with RF-positive RA. These results demonstrate that activation of the xanthine oxidase/xanthine dehydrogenase enzyme complex is an substantial factor of induction and continuation of the autoimmune rheumatoid inflammation.Disclosure of Interests:None declared

Study Objective: To study lymphocyte lysates for the dependence of the activity of xanthine oxidoreductase (XOR) complex: xanthine oxidase (XO) and xanthine dehydrogenase (XDG) — on the presence of extraarticular (systemic) manifestations (EAM) in patients with rheumatoid arthritis (RA). Study Design: Comparative study. Material and Methods. The study included 77 patients with verified RA (study group) and 35 apparently healthy subjects (control group). Lymphocytes were isolated using А. Böyum method in Lymphosep with a density gradient of 1.077–1.079 g/mL. Ferment activity was measured with kinetic methods and expressed in nM/min/mL equivalent to 107 cells per 1 mL. Study Results. XO reference range is 14.11–31.33 nM/min/mL; that of XDG — 18.62–39.64 nM/min/mL. For RA patients as a whole and patients with and without EAMs, lymphocytes demonstrated a significant reduction in the activity of both ferments vs controls (р < 0.001); in RA patients with EAMs, the XO and XDG activity was even lower (р < 0.001). Spearman correlation analysis identified the dependence of XO and XDG activity on the presence of EAMs: direct moderate correlations for XO (ρ = 0.6; p < 0.001) and XDG (ρ = 0.499; p = 0.000041). There is a strong direct correlation between XO and XDG activity, the intensity of which was higher where RA was associated with EAMs: (ρ = 0.72; p = 0.025) and (ρ = 0.87, p = 0.004) for RA only with articular involvement and for RA with EAMs, respectively. Conclusion. In lymphocytes of patients with RA, we found some changes in the XOR enzyme profile, the intensity of which depends on the presence of EAMs in the clinical presentation of the disease. Where XO activity is below 10.86 nM/min/mL and/or with XDG activity below 14.31 nM/min/mL, it is assumed that RA patients have EAMs. It is then recommended that the patient undergoes a comprehensive examination for early EAM identification and therapy adjustment. Keywords: rheumatoid arthritis, lymphocytes, xanthine oxidoreductase, xanthine oxidase, xanthine dehydrogenase.