[Sleep apnea and cardiovascular disease--results from animal studies]

Over the last decade the pathophysiology of obstructive sleep apnea (OSA)-related cardiovascular disease has been further elucidated in animal models employing dogs and rats/mice. It was demonstrated that, under the conditions of chronic intermittent hypoxia (CIH), endothelial dysfunction, i. e., a reduction in endothelial-dependent vasorelaxation, occurs. Furthermore, animals were shown to develop arterial hypertension when subjected to CIH for some weeks. Other aspects of the cardiovascular morbidity linked to OSA such as pulmonary hypertension, heart failure and atherosclerosis were also found in these animal models. The common result of these studies is that, apart from sympathetic over-activity, an increased oxidative stress seems to play a key role in the development of OSA-associated cardiovascular disease. It is anticipated that animal studies will continue to enhance our understanding of the pathogenesis of these disorders.