Reduced Peripheral Blood Mononuclear Cell ROCK1 and ROCK2 Levels in Obstructive Sleep Apnea Syndrome

Abstract

Abstract. Background Obstructive sleep apnea syndrome (OSAS) is one of the most frequent sleep disorders with a prevalence of 2-4% in the adult population, 3.1%-7.5% in men and 1.8%-5% in women (1-9). OSAS is characterized by repetitive episodes of apnea due to total compression of respiratory tract, intermittent hypoxia, reduced blood oxygen saturation and impaired sleep quality. It may cause difficulty sleeping, morning headache, daytime sleepiness, fatigue and reduced performance in daytime activities. Age, male gender and obesity have been listed among the risk factors of OSAS (1-3, 10). Moreover, OSAS has been associated with increased risk for arterial and pulmonary hypertension, cardiovascular and cerebrovascular disorders and metabolic syndrome (2,(11)(12)(13)(14).Although pathophysiological processes underlying OSAS have not been fully understood, inflammation, vascular endothelial dysfunction and altered body metabolism have been implicated (15,16). Rho-associated protein kinase (ROCK) enzyme is known to be involved in regulation of vascular functions and cardiovascular disease pathogenesis. ROCK activation has been shown to enhance endothelial permeability and induce angiogenic processes through regulation of endothelial gene expression (17). In several studies, ROCK enzyme activity has been shown to be altered in patients characterized with cardiorespiratory problems that might potentially lead to chronic hypoxia of the target tissue (e.g. brain, heart etc.) (18,19). In a single study, ROCK activity has been shown to be increased in OSAS in correlation with increased C-reactive protein (CRP) concentration and reduced flow-mediated dilatation in the brachial artery suggesting the presence of an interplay with ROCK and endothelial dysfunction (20).The present study was conducted to find out whether intermittent hypoxia induced by OSAS might alter ROCK1 and ROCK2 expression in the peripheral blood and thus levels of these proteins can be used to extrapolate the intensity of hypoxia induced by OSAS. Clinical and laboratory features that might potentially be associated with ROCK expression levels were also investigated. 319This article is freely accessible online.Correspondence to: Erdem Tüzün,