Objective: Obstructive sleep apnea syndrome (OSAS) is characterized by repetitive episodes of upper airway obstruction that occur during sleep which leads to cardiovascular, neurovascular and metabolic diseases. The mechanisms of complications in these patients are unclear. In this report, we aimed to determine the cause of oxidative imbalance in patients with OSAS and to evaluate the vascular endothelial dysfunction as a suspect for complications of the disease.
Materials and Methods: Fifty patients diagnosed as moderate or severe OSAS (AHI > 15) by polysomnography and 50 healthy volunteers are included in the study. By biochemical analysis of blood samples, serum malonyldialdehyde (MDA) levels measured to determine the oxidative stress, serum antioxidant enzymes glutathione peroxidase (GSH-Px), paraoxonase (PON) and arylesterase (ARE) activities measured to determine the antioxidant status and serum nitric oxide (NO) levels measured to show the vascular endothelial dysfunction. For statistically analysis, SPSS 15.0 is used with Mann-Whitney test to compare the results of patients and control group and Pearson Correlation Test to calculate the correlations.
Results: Serum MDA levels were significantly higher in patients with OSAS than control subjects (p < 0.05). The GSH-Px, PON, NO levels were significantly lower in OSAS group than control subjects (p < 0.05). The serum ARE activity was lower in OSAS group but this decrease was not statistically significant. There was a negative correlation between serum MDA levels and GSH-Px activity and a positive correlation between serum PON activities and ARE activities.
Conclusion: Obstructive sleep apnea syndrome is strongly associated with oxidative stress and abnormal lipid peroxidation. The oxidative stress depends on not only the overproducing of reactive oxygen species but also the deficiency of antioxidant defense systems. Both oxidative imbalance and vascular endothelial dysfunction lead to early development of atherosclerosis which may cause the health threatening complications of OSAS.
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