Clinical research
Circulating levels of vascular endothelial markers in obstructive sleep apnoea syndrome. Effects of nasal continuous positive airway pressure

Introduction : Obstructive sleep apnoea syndrome (OSAS) is an important risk factor in cardiovascular disorders. Although the exact mechanism remains to be elucidated, the endothelial dysfunction process seems to be implicated.

Material and methods : In order to test this hypothesis, blood circulating levels of endothelial markers were measured at baseline and 1 year after treatment with continuous positive airway pressure (CPAP). We studied 37 males using polysomnography: 20 subjects with OSAS and a 17-subject control group. An OSAS-validated sleep questionnaire covering the most important cardiovascular risk factors was applied to all subjects. Furthermore, patients received a complete general physical examination and biochemistry test with lipid profile. The specific markers measured were intercellular cell adhesion molecule-1 (ICAM-1), E-selectin, endothelin-1, von Willebrand factor (vWF) and plasminogen activator inhibitor-1 (PAI-1).

Results : Obstructive sleep apnoea syndrome patients presented higher circulating levels of ICAM-1, endothelin-1 and PAI-1 than the control group. On the other hand, no differences were found in E-selectin and vWF. After 1 year of CPAP treatment, there was a significant decrease in circulating levels of ICAM-1 and PAI-1. On the other hand, no differences were found in endothelin-1, E-selectin and vWF.

Conclusions : Obstructive sleep apnoea syndrome is associated with elevated levels of ICAM-1 and PAI-1 and these levels normalize after treatment with CPAP.