Study On The Relationship Between Cognitive Impairment And Oxidative Stress In Obstructive Sleep Apnea-hypoapnea Syndrome

ObjectiveTo investigate the correlation of oxidative stress and cognitive impairment in patients with obstructive sleep apnea-hypopnea syndrome(OSAHS), and further evaluate the effect of continuous positive airway pressure(CPAP) treatment on both the cognitive functions and serum oxidative biomarkers in OSAHS patients.MethodsA total of 119 eligible patients with moderate-to-severe OSAHS were enrolled in the study, including 33 patients(28%) with cognitive impairment(CI) based on the Montreal Cognitive Assessment Scale(Mo CA) score < 26 points and 86 patients with normal cognitive function(NC, Mo CA score ≥ 26 points). PSG data of all the patients was recorded overnight followed by the assessments of Mo CA, MMSE and Epworth sleepiness scale in the next morning. The serum levels of three oxidative biomarkers, i.e.,malondialdehyde(MDA), advanced protein oxidation products(AOPP) and ischemia modified albumin(IMA) were measured by ELISA. In addition, 19 patients treated with CPAP for at least 6 months were included to evaluate the efficacy of CPAP treatment.ResultsCompared to NC group, waist-to-height ratio(WHR), apnea/hypopnea index, oxygendesaturation index, and time ratio of Sa O2 lower than 90% in the CI group were significantly higher, while mean Sa O2 was lower(p<0.05). The serum levels of all three oxidative biomarkers were also significantly elevated in the CI group(MDA: 8.58±5.63 vs.4.85±2.03 nmol/ml, p<0.05; AOPP: 137.25±43.25 vs. 96.21±26.46 umol/L, p<0.01; IMA:117.56±40.11 vs. 67.50±17.46 k U/L, p<0.01). The stepwise logistic regression analysis revealed that the CI significantly correlated with the serum IMA level, age and time ratio of REM. The 6-month CPAP treatment improved the overall(p<0.05) and selected Mo CA subdomain scores, and also significantly reduced serum levels of oxidative stress biomarkers(p<0.01).ConclusionsCognitive impairment is common in young and middled-aged patients with moderate-to-severe OSAHS and significantly correlates to elevated oxidative stress. CPAP treatment with good adherence markedly decreased the serum oxidative stress biomarker levels while improving Mo CA-assessed neurocognitive performance.ObjectiveTo preliminary investigate the effect of oral high-dose N-acetylcysteine(NAC) on patients with moderate-to-severe obstructive sleep apnea-hypopnea syndrome(OSAHS),and further evaluate clinical perspective of NAC.MethodsFrom February 2014 to June 2015, a total of 46 eligible patients diagosed withmoderate-to-severe OSAHS were enrolled in the study, randomized into the two groups,NAC or placebo. Measurements of fasting glucose, lipid profiles and CRP were arranged in the morning, and assessments of Mo CA, MMSE and Epworth sleepiness scale were followed next. The serum levels of three oxidative biomarkers, i.e., malondialdehyde(MDA), advanced protein oxidation products(AOPP) and ischemia modified albumin(IMA) were measured by ELISA. After finishing the follow-up, PSG, blood parameters and neurocognitive scales mentioned above were measured again.ResultsThere were 40 patients finished the 6 months’ follow-up(NAC:21; placebo:19).Changes between the two groups of BMI and percentages of sleep stage after therapy were not significant. Compared to placebo group, AHI and T90 were slightly lower, and average Sa O2 were elevated after 6 months in NAC group, and the changes between two groups were statistical significant(p<0.05). The 6-month NAC treatment improved the overall and selected Mo CA subdomain scores(p<0.05), and also significantly reduced serum levels of oxidative stress biomarkers(p<0.01).ConclusionsNAC can improve the condition of intermittent hypoxia induced by apnea/hypopnea,and decrease levels of serum oxidative stress biomarker levels, while improving Mo CA-assessed neurocognitive performance. Long-term oral high-dose NAC to treat OSAHS deserves to be further investigated.Clinical trial registration: Chi CTR-TRC-14004578.