įrom previously published works there is known the association between intermittent hypoxia and a wide range of pathological processes, such as endothelial dysfunction, activation of the sympathetic nervous system, systemic inflammatory response, impaired glucose and lipid metabolisms. Elevation of the atherogenic index of plasma was observed in the OSA population and it was related to the disease severity. To date, it has not been clearly explained which pathophysiological mechanisms of OSA lead to the development of vascular diseases. In Europe, the disease affects more than 20% of the middle-aged adult population and the prevalence even exceeds 50% in some countries. It is a disorder characterized by episodes of breathing interuption during sleep, leading to chronic intermittent hypoxia and sleep fragmentation by numerous awakening periods. One of the most common sleep disorders characterized by an increased risk of vascular disease is obstructive sleep apnea (OSA). Abnormalities in lipoprotein levels in patients with OSA, as well as the redox imbalance, could lead to an acceleration of the atherosclerotic process in predisposed individuals and thus represent a significant risk factor for vasular diseases. In addition, a plasma redox imbalance was found in patients with OSA compared to controls by detecting higher oxidative damage to lipids. The lipoprotein pro-atherogenic phenotype was found in individuals with OSA characterized by increased levels of atherogenic lipoprotein subfractions and reduced levels of atheroprotective subfractions. Lipoperoxide levels in patients with OSA were significantly elevated compared to healthy individuals. Of the LDL and HDL subfractions, OSA patients had significantly lower levels of atheroprotective LDL1 and large HDL subfractions and significantly higher levels of atherogenic small dense LD元–7 and HDL8–10 subfractions. HDL cholesterol was not significantly different. OSA patients had significantly higher triacylglycerols, total cholesterol and LDL-cholesterol compared to healthy controls.
Lipoperoxide levels were determined spectrophotometrically.
Plasma LDL and HDL subfractions were separated by the Lipoprint system which is a polyacrylamide gel electrophoresis. Plasma levels of total cholesterol, LDL and HDL and their subfractions, triacylglycerols and lipoperoxides were determined in all study individuals. The study included 15 male subjects with polysomnographically confirmed OSA and 16 male healthy controls. The main aim of this study was the evaluation of the presence of lipid abnormalities in OSA patients, focusing on small dense low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subfractions and determination of the redox imbalance by evaluating the marker of oxidative damage to plasma lipids - lipoperoxides. Dyslipidemia and redox imbalance belong to potential mechanisms linking OSA with the development of vascular diseases. Obstructive sleep apnea (OSA) is a disorder with a significant risk for cardiovascular diseases.