Oxidative stress and oxidant signaling in obstructive sleep apnea and associated cardiovascular diseases

Abstract

Obstructive sleep apnea (OSA) has emerged as a major public health problem and increasing evidence indicates that untreated OSA can lead to the development of various cardiovascular disorders. One important mechanism by which OSA may promote cardiovascular diseases is intermittent hypoxia, in which patients are subjected to repeated episodes of brief oxygen desaturation in the blood, followed by reoxygenation. Such cycles of hypoxia/reoxygenation may result in the generation of reactive oxygen species. Some studies have demonstrated the presence of oxidative stress in OSA patients as well as in animals subjected to intermittent hypoxia. Further, modulations of nitric oxide and biothiol status might also play important roles in the pathogenesis of OSA-associated diseases. Reactive oxygen species and redox events are also involved in the regulation of signal transduction for oxygen-sensing mechanisms. This review summarizes currently available information on the evidence for and against the occurrence of oxidative stress in OSA and the role of reactive oxygen species in cardiovascular changes associated with OSA.

Sleep Apnea and Cardiovascular Disease

“…[97][98][99] Some studies have reported increased levels of thiobarbituric acid reactive substances, isoprostanes, and oxidized low-density lipoprotein in OSA, 100 although these changes have not been confirmed in other studies. 101 Circulating free nitrotyrosine, a marker of nitrosative oxidative stress, is not elevated in OSA patients.…”

Contribuição da apnéia obstrutiva do sono para o estresse oxidativo da obesidade

“…As alterações repetidas na saturação sangüínea, presentes nos episó-dios de apnéia/hipopnéia e hipóxia-reoxigenação da AOS são similares ao quadro da injúria isquemia-reperfusão tecidual, promovendo danos aos vasos sangüíneos quando o fluxo é restaurado, em razão do aumento da produção de radicais livres (19,20). Estas espécies reativas de oxigênio reagem com ácidos nucléicos, lipídeos e proteínas e ainda reduzem a produção de nitritos e nitratos séricos, causando lesão endotelial, fator de risco fortemente associado às doenças cardiovasculares (21,22).…”

Effect of Short Term C PAP Therapy in Obstructive Sleep Apnea Patients with Metabolic Syndrome

“…Though the cause for such abnormalities in OSA is not clear, oxidative stress has been proposed to be one of the important factors in the pathogenesis of these metabolic abnormalities. The chronic nocturnal intermittent hypoxia occurring in OSA mimics ischemia-reperfusion injury that has been associated with increased production of vascular ROS which promotes oxidative stress [5]. We also found a significant reduction of lipid peroxidation after one night of CPAP treatment [Table/ Fig-3].…”

“…In India the prevalence of OSA is estimated to be 13.7% [2] and the prevalence of metabolic syndrome in OSA patients ranges from 4.5% in population-based study [3] to 79% among patients with OSA in hospital-based study [4]. There is cumulative evidence suggesting the presence of increased oxidative stress in OSA patients [5]. In our previously published study we have demonstrated an increased lipid peroxidation and decreased total reduced glutathione levels indicating an imbalance between reactive oxygen species (ROS) and antioxidant capacity [6].…”