Investigation of serum nuclear factor erythroid 2-related factor 2 (NRF2) level, oxidative stress parameters and thiol-disulfide homeostasis in patients diagnosed with fibromyalgia syndrome

Aim: Fibromyalgia Syndrome is a disease whose etiopathogenesis is still unknown despite numerous studies. In this study, we compared serum Nrf2, Total Antioxidant Status (TAS), Total Oxidant Status (TOS) levels and Thiol-Disulfide Homeostasis in female patients diagnosed with Fibromyalgia Syndrome (FMS) with healthy population and investigated the relationship between Nrf2 levels and oxidative stress parameters and clinical findings in the patient group. This is the first study in the literature evaluating serum Nrf2 levels in FMS. Material and Method: A total of 110 participants, including 60 patients diagnosed with FMS and 50 healthy controls, who were admitted to the Physical Medicine and Rehabilitation and Rheumatology outpatient clinics of Gaziantep University Şahinbey Research and Practice Hospital were included in the study. The study was planned as cross-sectional and collection of serum samples, physical examination and clinical evaluation were made in a single session. Nrf2 level was measured by ELISA method, TAS, TOS, Native Thiol (N.T.), Total Thiol (T.T.) and Disulfide levels were measured by spectrophotometric method. Sociodemographic and clinical characteristics of all participants including age, body mass index, exercise habits, disease duration and medication use were recorded on the Participant Information Form. For Diagnosis ACR Revised 2016 Criteria; for pain intensity the Visual Analog Scale (VAS); for disease severity the Fibromyalgia Impact Questionnaire (FIQ); for emotional status the Beck Depression and Anxiety Scales (BDI, BAI); for sleep disturbance, Pittsburgh Sleep Quality Index (PSQI); for fatigue status, Fatigue Severity Scale (FSS); for neuropathic pain severity, Douleur 4 Question Neuropathic Pain Questionnaire (DN4) were used. The number of tender points (TP) was also recorded for each participant. Results: There was no significant difference between the groups in terms of age. In the patient group, the count of TP, FIQ, BDI, BAI, PSQI, FSS, DN4 score averages were higher than in the control group (p<0.001, for all), TAS and TOS levels were significantly higher than in the control group (p<0.001, for both). VAS pain score, TAS and TOS levels were found to be statistically significantly higher than in the control group (p<0.05). Nrf2 levels were found to be significantly lower in the patient group (p<0.001), however, a negative correlation was found between DN4 scores and Nrf2 levels in the patient group (r=-0.255, p=0.049). Conclusion: The results of our study are promising in terms of the etiopathogenesis, diagnosis and treatment pathways of Nrf2 in patients with FMS, in the future studies, especially in subgroups with neuropathic pain, the use of Nrf2 activators in patients with low Nrf2 levels may be on the agenda. However, more extensive studies are needed to confirm these results. Intensive studies are ongoing to elucidate the etiology of Fibromyalgia Syndrome.