Evaluation of thiol/disulfide homeostasis in rheumatoid arthritis and disease activity

Abstract

BackgroundIt has been suggested that the deterioration in the antioxidant defense system due to thiols may cause the pro-oxidant/antioxidant imbalance seen in rheumatoid arthritis (RA). This study was conducted to evaluate thiol/disulfide (−SH/−SS) homeostasis in patients with RA compared to healthy controls, and to validate the limited number of studies examining the relationship between Disease Activity Score-28 (DAS28) and thiol parameters. MethodA total of 100 individuals (mean age: 46.3 ± 12.03) consisting of 86 females and 14 males were included in the RA group, and a total of 100 individuals (mean age: 43.3 ± 10.96 years) consisting of 78 females and 22 males were included in the control group. DAS28 was used to assess RA disease activity. −SH/−SS homeostasis parameters were measured using the automated spectrophotometric method described by Erel and Neselioğlu. ResultsWhile native thiol (−SH) (p:0.001), total thiol (−SH + −SS) (p < 0.0001) levels and −SH\\(−SS + −SH) ratio (p: 0.018) were lower in the RA group compared to the healthy controls, disulfide (−SS) level (p: 0.005)), −SS\\−SH (p: 0.001) and −SS\\(−SS + -SH) (p: 0.002) ratios were found to be higher. In the control group and the group in remission (defined by DAS28 < 2.6), the median values of –SH (p:0.002) and −SS + −SH (p:0.0008) were found to be significantly higher, and the median value of –SS (p: 0.001) was found to be lower compared to the other DAS28 groups. While a negative correlation was found between DAS28 and –SH (r: −0.243, p: 0.007), a positive correlation was found between DAS28 and −SS (r: 0.316, p: 0.0003), −SS\\−SH (r:0.229, p: 0.002) and −SS\\(−SS + −SH) (r: 0.285, p: 0.0009). ConclusionsThe plasma thiol antioxidant pool was decreased in RA compared to healthy controls and those with active disease compared to those in remission.