The impact of sleep apnea syndrome on the altered lipid metabolism and the redox balance

Abstract

Background Obstructive sleep apnea (OSA) is a disorder with a significant risk for cardiovascular diseases. Dyslipidemia and redox imbalance belong to potential mechanisms linking OSA with the development of vascular diseases. 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. Methods The study included 15 male subjects with polysomnographically confirmed OSA and 16 male healthy controls. Plasma levels of total cholesterol, LDL and HDL and their subfractions, triacylglycerols and lipoperoxides were determined in all study individuals. Plasma LDL and HDL subfractions were separated by the Lipoprint system which is a polyacrylamide gel electrophoresis. Lipoperoxide levels were determined spectrophotometrically. Results OSA patients had significantly higher triacylglycerols, total cholesterol and LDL-cholesterol compared to healthy controls. HDL cholesterol was not significantly different. 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 LDL3–7 and HDL8–10 subfractions. Lipoperoxide levels in patients with OSA were significantly elevated compared to healthy individuals. Conclusion 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. In addition, a plasma redox imbalance was found in patients with OSA compared to controls by detecting higher oxidative damage to lipids. 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.

Association of Obstructive Sleep Apnea Syndrome (OSA/OSAHS) with Coronary Atherosclerosis Risk: Systematic Review and Meta-Analysis

“…The selected studies in this study were verified to have no publication bias, and sensitivity analysis also showed that the results of this study were relatively stable [ 25 ]. Therefore, it can be considered that the effect of this study is relatively reliable.…”

Obstructive Sleep Apnoea and Lipid Metabolism: The Summary of Evidence and Future Perspectives in the Pathophysiology of OSA-Associated Dyslipidaemia

“…Several modified LDL particles were identified, such as oxidised LDL (oxLDL), small dense LDL (sdLDL) and desialylated LDL, which are strongly atherogenic [ 28 , 29 , 30 ]. Further subclasses can be identified by gel electrophoresis: large (LDL 1–2) and small (LDL 3–7) subfractions [ 31 ]. Circulating LDL particles are absorbed by the liver (70%) and peripheral tissues (30%), mainly by the LDL receptor (LDLR) [ 32 ].…”

“…These can further be divided into HDL3c, HDL3b, HDL3a, HDL2a and HDL2b fractions [ 57 ]. Further subclasses can be identified by gel electrophoresis: large (HDL 1–3), intermediate (HDL 4–7) and small (HDL 8–10) subfractions [ 31 ]. The small HDL 8-10 particles are atherogenic through easy penetration to the endothelium and low recognition by HDL receptors [ 59 , 60 ].…”

“…Pro-atherogenic sdLDL3–7 subfractions were significantly higher in the OSA group [ 31 ]. SdLDL particles were independently associated with OSA in non-obese participants [ 167 ].…”

Correlation of Dyslipidemia and Inflammation With Obstructive Sleep Apnea Severity

“…Our study showed a significant correlation of HDL with OSA severity, indicating that patients with lower HDL values have higher Apnea-Hypopnea Index (AHI). Considering protective cardiovascular effects of high-density lipoproteins (HDL), it is shown that certain subfractions of HDL, especially small HDL subfractions including small LDL3–7 and small HDL8–10, can have atherogenic effects in patients with OSA ( Kollar et al, 2021 ). On the other hand, bigger HDL subfractions can have impaired antioxidant activity because of increased HDL lipid peroxide levels and decreased serum paraoxonase-1 (PON1) activity, which are the two main factors related to the antioxidant activity of HDL ( Yadav et al, 2014 ).…”