Thiol/disulfide homeostasis as a novel indicator of oxidative stress in obstructive sleep apnea patients.

OBJECTIVES: The aim of the present study was to assess thiol/disulfide (SS) homeostasis as a novel indicator of oxidative stress in patients with obstructive sleep apnea (OSA) and to investigate the effect of continuous positive airway pressure (CPAP) therapy on oxidative parameters. STUDY DESIGN: Prospective clinical study. METHODS: A total of 104 subjects, 44 in an OSA group and 60 in two control groups (control simple snoring group, control OSA group) were included. The levels of parameters were measured using the Erel and Neselioglu method in patients with moderate or severe OSA before and after CPAP therapy. RESULTS: The serum native thiol (SH) and total SH levels as well as the %SH/total SH ratio were significantly lower (P < 0.05) in OSA patients compared to controls, and the SS level and %SS/SH and %SS/total SH ratios were significantly higher (P < 0.05). After CPAP therapy, the native SH level and %SH/total SH ratio were significantly higher (P < 0.05) than before CPAP therapy, and the SS level and %SS/SH and %SS/total SH ratios were significantly lower (P < 0.05). Significant negative correlations were evident between the apnea/hypopnea index (AHI) and the native SH level and %SH/total SH ratio (P < 0.05) before CPAP therapy; and significant positive correlations were seen between the AHI and the %SS/SH and %SS/total SH ratios but not with the SS level. CONCLUSION: We found that oxidative stress was increased and CPAP therapy had a positive effect in patients with moderate or severe OSA. LEVEL OF EVIDENCE: 3b. Laryngoscope, 127:E244-E250, 2017.

A new oxidative stress marker for thiol-disulphide homeostasis in seasonal allergic rhinitis.

BACKGROUND: Reactive oxygen species has a crucial role in the pathogenesis of many diseases. Reactive oxygen species has been effectively documented in patients with asthma, but very little research has been reported in subjects with allergic rhinitis. OBJECTIVES: To investigate thiol (SH)-disulfide (SS) homeostasis, a new oxidative stress marker present in patients with seasonal allergic rhinitis (SAR). METHODS: A total of 64 subjects, including 32 patients with SAR and 32 healthy controls, were included in the study. We measured the SH levels as a marker of antioxidant protection and SS as a marker related to oxidant stress. Sera specimens were taken from patients with SAR during exacerbation and during asymptomatic time periods. In addition, sera samples from the control group were also obtained during the pollen season to compare with those from patients with SAR. RESULTS: In patients with SAR, during exacerbation periods, SH, SS, % SS/SH, % SS to total SH (TT), and % SH/TT were significantly different (p < 0.05) than in patients with SAR during asymptomatic periods. Although SS was significantly higher in patents with SAR during exacerbation periods, SH was significantly higher in patients with SAR during asymptomatic periods. Patients with SAR during asymptomatic periods and the control group did not significantly differ (p > 0.05) regarding SH, SS, TT, % SS/SH, % SS/TT, and % SH/TT. CONCLUSION: SAR is a disorder that elevates systemic oxidative stress and reduces antioxidant enzyme activities. Our results shed light on the etiopathogenesis of the disease and can help develop new therapeutic approaches.

Association between thyroid hormone levels and insulin resistance and body mass index.

OBJECTIVE: Previous studies have shown an association between thyroid function and insulin resistance and obesity. We compared insulin resistance and body mass index (BMI) in patients with normal TSH levels (2.5-4.2 µIU/mL), patients diagnosed with subclinical hypothyroidism, and healthy control subjects. METHODS: The study included 104 subjects and was conducted at the Taksim Education and Research Hospital. The subjects were divided into three groups according to TSH levels: Group 1 (high-normal), TSH levels were 2.5-4.2 µIU/mL (n=33); Group 2 (subclinical hypothyroidism), TSH levels were 4.2-10 µIU/mL (n=42); and Group 3 (healthy control), TSH levels were 0.27-2.5 µIU/mL (n=29). The fT3 and fT4 levels were within normal limits in all groups. Insulin resistance and BMI were compared among groups. The homeostasis model assessment of insulin resistance (HOMA-IR) was used to estimate insulin resistance. RESULTS: HOMA-IR and BMI were not significantly different among groups (p>0.05). A significant positive correlation was found between BMI and HOMA-IR in the high-normal TSH (p>0.059) and subclinical hypothyroidism (p>0.05) groups. CONCLUSIONS: HOMA-IR and BMI are important for the assessment of diabetes and cardiovascular diseases. We found no significant difference in HOMA-IR and BMI values among the three TSH reference range groups.