Evaluation of the relationship between oxidative stress and inflammation in patients with severe obstructive sleep apnea

Obstructive sleep apnea syndrome (OSAS) is a condition characterized by the occurence of repetitive episodes of partial or complete obstruction of airflow during sleep. Obstruction usually occurs in the upper airway and may lead to decreased blood oxygenation and fragmentation of the sleep cycle.Although the etiology of OSAS is uncertain, intense local and systemic inflammation are present in these patients. In obstructive sleep apnea syndrome, upper airway inflammation has a potential role in upper airway collapse, whereas systemic inflammation relates to cardiovascular morbidity. The presence of systemic inflammation, characterized by elevated levels of certain potent pro-inflammatory mediators, such as C reactive protein, leptin, TNF-?, IL-6, may predispose to the development of cardiovascular complications observed in patients with OSAS. One of the relatively less studied underlying mechanisms that may be involved in the development of cardiovascular disease in sleep apnoea syndrome, is the formation of hypoxia-related free radicals and increased oxidative stres due to the intermittent hypoxia.In our study, serum malondialdehit (MDA) and c-reactive protein (CRP) levels and eritrosit sedimentation rate (ESR) of 65 severe OUAS patient (47 men, 18 women) and 27 healthy (18 men, 9 women) have been investigated during controls. It is found that medium MDA and CRP levels in ESR patients, respectively, 2.83 (1.12) ?mol/L, 7.49 (10.23) mg/L ve 13.75 (12.07) mm/h and during controls, respectively 2.04 (0.65) ?mol/L, 8.08 (12.47) mg/L ve 15.72 (12.04) mm/h. While there is a significant difference in MDA levels between patient and control stastistically, there is no difference between CRP levels and ESR. In patients, there is a positive but an nonsignificant correlation has been observed between MDA and hs-CRP. Age, gender, body mass index, smoking and drinking behaviours have also been investigated on parameters of patients and controls.In our study, while there is an increase on the MDA levels of severe OUAS patients which is an indicator of lipid peroxidation as a result of repetitive hipoxia/reoxygenation, there has been no change on hs-CRP levels which is an inflammation indicator and ESH. In addition, it was observed a weak positive correlation between MDA and hs-CRP levels.