Circulating nitric oxide (NO), asymmetric dimethylarginine (ADMA), homocysteine, and oxidative status in obstructive sleep apnea–hypopnea syndrome (OSAHS)

Abstract

Obstructive sleep apnea-hypopnea syndrome (OSAHS) with episodic hypoxia-reoxygenation is associated with increased cardiovascular morbidity and mortality. Therefore, increased homocysteine, asymmetric dimethylarginine (ADMA), oxidative status, and decreased nitric oxide levels have been implicated as possible mechanisms for development of cardiovascular diseases. We aimed to investigate changes in the levels of these substances in patients with OSAHS in comparison with nonapneic controls. Thirty-four OSAHS patients and 15 healthy controls were included in this study. In the blood samples, oxidative status and nitric oxide levels were measured with spectrophotometric methods. Plasma ADMA and homocysteine levels were determined by using high-performance liquid chromatography with fluorescence detection. Nitric oxide levels were significantly low in OSAHS patients (p < 0.05) and correlated with mean SaO(2) (r = 0.513, p < 0.002) and lowest SaO(2) (r = 0.363, p < 0.03). Oxidative status, ADMA, and homocysteine levels were higher in OSAHS patients, but difference did not reach statistical significance. After dividing patients into moderate (AHI = 5-29) and severe (AHI > or = 30) OSAHS groups, significantly increased homocysteine levels were observed in the severe OSAHS group (p < 0.05). Nitric oxide levels negatively correlated with oxidative status in total OSAHS patients (r = -0.415, p < 0.02) and also in severe OSAHS group (r = -0.641, p < 0.007). Hyperhomocysteinemia and diminished NO production may be causal factors in endothelial dysfunction seen in OSAHS and may explain the association between OSAHS and cardiovascular diseases. These modifiable factors should be monitored in patients suspected of having OSAHS.

Increased Asymmetric Dimethylarginine and Ischemia-Modified Albumin Levels in Obstructive Sleep Apnea

“…21,22 Increased plasma concentration of asymmetric dimethylarginine is associated with hypertension, pulmonary hypertension, hypercholesterolemia, and severe peripheral artery occlusive diseases. 15,17,23,24 These findings suggest that asymmetric dimethylarginine is responsible for endothelial dysfunction. Barceló et al 25 assessed plasma asymmetric dimethylarginine in subjects with OSA and found it to be significantly higher in these subjects irrespective of the presence of further cardiovascular risk.…”

Hyperhomocysteinaemia predicts the decline in pulmonary function in healthy male smokers

“…In the present study, multiple linear regression analyses were performed to control for the influence of factors other than homocysteine levels on pulmonary function. OZKAN et al [44] previously demonstrated that serum homocysteine levels were significantly higher in patients with severe sleep apnoea syndrome than in controls, suggesting that tissue hypoxia may be associated with the level of serum homocysteine. However, arterial oxygen tension and saturation were not measured in this population, and this was a limitation of our study.…”

The Relationship Between Obstructive Sleep Apnea Hypopnea Syndrome and Inflammatory Markers and Quality of Life in Subjects With Acute Coronary Syndrome

“…20 Levels of homocysteine are mediated by endothelial injury, altered coagulation, and platelet activation. Our data show higher homocysteine levels in subjects with more severe OSA.…”