Anti-oxidant treatment in obstructive sleep apnoea syndrome.

Purpose. To investigate whether oral intake of N-acetylcysteine (NAC) is a treatment option in patients with obstructive sleep apnoea syndrome (OSAS). Methods. Twenty patients with OSAS were enrolled in the study. After polysomnography (PSG), they were randomly assigned to receive a placebo (n=10) and NAC (n=10). A repeat PSG was done after the treatment period of 30 days. Fasting venous samples were collected for various biochemical analysis. Results. In the patients of NAC group, compared to their baseline values, slow wave sleep as sleep percent time (27.9±2.7 vs 42.3±4.2; p<0.01) and sleep efficiency (90.8±1.3 vs 94.4±1.5; p<0.05) improved considerably. The apnoea-hypopnoea index (61.2±8.5 vs 43.1±8.6; p<0.05), apnoea related arousals (22.2±7.6 vs 11.6±4.7; p<0.05), longest apnoeic episode duration (seconds) (54.9±7.1 vs 37.8±5.6; p<0.01), oxygen desaturation events per hour (51.8±7.7 vs 37±7.8; p<0.01) and epworth sleepiness score (16.6±0.8 vs 9.2±0.9; p<0.001) decreased significantly. The relative snore time (%) (10.2±2.9 vs 4.9±1.9; p<0.01), number of snore episodes (63.8±23.9 vs 28.2±9.9; p<0.05) and duration of longest snore episode (min) (2.5±0.7 vs 0.6±0.1; p<0.05) also decreased significantly. Such responses were not evident in the placebo group. N-acetylcysteine produced significant decrease in lipid peroxidation and increase in total reduced glutathione. Conclusions. Oral NAC administration appears to have a therapeutic potential in the treatment of OSAS. It is proposed that long-term treatment with NAC in patients with OSAS may reduce their dependency on continuous positive airway pressure therapy.

Role of nitric oxide in the diuresis and natriuresis occurring in patients with obstructive sleep apnoea syndrome.

Objective. To determine whether nitric oxide (NO) has any role in the diuresis and natriuresis observed in patients with obstructive sleep apnoea syndrome (OSAS). Methods. We measured 12-hour urine volume in the day and in the night in patients with OSAS (n=20) and determined the concentrations of urinary sodium and nitrate. The frequency of urination in the night was also noted. The measurements were done again after two nights of continuous positive airway pressure (CPAP) therapy and after putting the patients on oral anti-oxidant treatment (vitamin C–100mg BD and vitamin E–400IU BD) for 45 days. Ten healthy normal subjects underwent the same protocol except the CPAP therapy. Results. In patients with OSAS, the night urine volume and sodium concentration were similar and the nitrate levels were higher compared to those in the day. After CPAP therapy, while the urine volume and sodium concentration decreased, the nitrate level became similar to that in the day. Such effects were not observed after anti-oxidant treatment. The frequency of urination was decreased in both the instances. The effects observed after CPAP therapy were similar to those observed in control subjects with or without anti-oxidant treatment. Conclusion. Renal NO promotes diuresis and natriuresis in patients with OSAS.

Oxidative stress and obstructive sleep apnoea syndrome.

Rationale. Even though oxidative stress has been proposed as an underlying mechanism for the symptoms in patients with obstructive sleep apnoea syndrome (OSAS), little information is available on the effects of anti-oxidant treatment on their improvement. Objectives. To observe the effects of anti-oxidant treatment on polysomnographic parameters and oxidative stress markers in OSAS patients. Methods. Polysomnography (PSG) was performed on 20 male patients. They were administered continuous positive airway pressure (CPAP) therapy for two nights followed by oral intake of vitamin C (100 IU BD) and vitamin E (400 IU BD) for 45 days and a repeat PSG was done. Ten healthy normal subjects underwent the same protocol excepting the CPAP therapy. Results. In OSAS patients, plasma lipid peroxidation increased significantly and whole blood reduced glutathione decreased significantly. The CPAP therapy as well as anti-oxidant treatment reduced the lipid peroxidation and restored the reduced glutathione concentrations. After anti-oxidant intake, OSAS patients slept better with decrease in Epworth sleepiness score and the number of apnoeic episodes. They spent more time in stages 3 and 4 of sleep. The optimum pressure of CPAP device was significantly lowered also. Conclusions. Oxidative stress contributes to sleep behaviour in OSAS patients, and anti-oxidant intake improves the quality of sleep in them.