ASSOCIATIONS BETWEEN EFFICACY OF THE THERAPY AND CIRCADIAN FLUCTUATIONS OF ENDOTHELIAL NITRIC OXIDE SYNTHASE WITH...

Despite significant progress in treatment of rheumatoid arthritis (RA), a considerable part of patients remains resistant to the current therapy, apparently for the reasons of undefined mechanisms of its pathogenesis. Recently, the disturbances of circadian regulation of inflammatory processes in RA have been highlighted as important ones. Endothelial nitric oxide synthase (NOS3) and soluble toll-like receptors 2 (sTLR2) take part in the regulation of angiogenesis, osteoclastogenesis, immune responses but their circadian rhythms and predictive significance in RA patients are still unknown. Aim - to estimate the associations between efficacy of treatment and the circadian rhythms of NOS3 and sTLR2, and NOS3 polymorphism in females with rheumatoid arthritis, Ukraine. 97 RA patients (100% female) aged 46.3±8.89 years with disease duration 8.44±6.52 years were examined. All patients as a disease-modifying therapy received methotrexate (MTX) orally in a dose ≤15 mg/week, folic acid 5 mg/week, NSAIDs and corticosteroids (CS) ≤10 mg/day by prednisone. Doses of MTX, NSAIDs and CS were stable 4 weeks prior to the enrolment and during the whole period of study. The efficacy end points included DAS28, RAID and American College of Rheumatology response criteria (ACR20/50/70). Serum levels of NOS3 and sTLR2 were determined at 08:00 and 20:00 using Cloud-Clone Corp kits (USA). NOS3 T-786С polymorphism was determined by Real-Time PCR. The SPSS22 software package was used for statistical processing of the results. The study was performed in accordance to the bioethical standards. After 12-week treatment among RA patients were revealed 52.6% ACR 20 responders and 47.4% non-responders. Opposite diurnal variation of NOS3 and sTLR2 serum levels were found in RA patients. There were significant differences in NOS3/sTLR2 ratio at 08:00 accordingly to NOS3 T786C genotype. The disturbances in daily variability of NOS3 or sTLR2 serum levels were more significant in non-responders compare to responders. Decrease of NOS3/sTLR2 ratio was a predictor of non-response to treatment in RA patients (β=0.366, р=0.000). In RA patients the disturbances of circadian rhythms of endothelial nitric oxide synthase or toll-like receptors 2 expression are associated with an increase of resistance to disease-modifying therapy with methotrexate.