Correlation between the serum level of advanced oxidation protein products and the cognitive function in patients with obstructive sleep apnea hypopnea syndrome

Abstract

To observe the change of the cognitive function and the serum level of advanced oxidation protein products (AOPP) in patients with obstructive sleep apnea hypopnea syndrome (OSAHS), and then to investigate the correlation between them. Sixty seven patients with OSAHS, 20 healthy controls with matched age, BMI, and education, 15 patients with OSAHS after effective treatment of continuous positive airway pressure (CPAP) with matched age, BMI, and education were enrolled. Polysomnography (PSG), Epworth sleepiness scale (ESS), mini-mental state examination (MMSE), and clock drawing test (CDT) were performed in these groups. The serum level of AOPP, superoxide dismutase (SOD), and malondialdehyde (MDA) were measured. The MMSE and CDT scores of patients with OSAHS were decreased compared to those in healthy controls [(4.73 ± 0.81) vs (2.69 ± 1.38), (2.85 ± 0.61) vs (1.92 ± 0.62)], but the scores improved after effective CPAP treatment. The serum levels of AOPP [(78 ± 20) vs (117 ± 20) µmol/L] and MDA [(2.9 ± 1.0) vs (6.1 ± 3.0) µmol/L] in patients with OSAHS were increased compared to those in healthy controls, but the levels decreased after effective CPAP treatment. The serum SOD level in patients with OSAHS was decreased compared to that in healthy controls [(89 ± 8) vs (57 ± 9) U/ml], but it was increased after effective CPAP treatment. The MMSE and CDT scores of all the subjects including the 2 groups (the OSAHS group and the effective CPAP-treatment group) were correlated with the results of PSG (baseline SaO2, lowest SaO2, AHI, LA/HT, SLT90%). The serum levels of AOPP, MDA and SOD of all the subjects were also correlated with the results of PSG (lowest SaO2, AHI, LA/HT, SLT90%). The serum levels of AOPP, MDA and SOD of all the subjects were correlated with the MMSE and CDT scores. The serum level of AOPP of all the subjects was also correlated with the serum levels of MDA and SOD. Cognitive impairment in patients with OSAHS is correlated with the severity of the disease. AOPP is a useful marker for oxidative stress and protein injury, and closely correlated with the cognitive impairment in patients with OSAHS.