Associations between Endothelial Lipase, High-Density Lipoprotein, and Endothelial Function Differ in Healthy Volunteers and Metabolic Syndrome Patients

Abstract

Metabolic syndrome (MS) is characterized by endothelial- and high-density lipoprotein (HDL) dysfunction and increased endothelial lipase (EL) serum levels. We examined the associations between EL serum levels, HDL (serum levels, lipid content, and function), and endothelial function in healthy volunteers (HV) and MS patients. Flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), serum levels of HDL subclasses (measured by nuclear magnetic resonance (NMR) spectroscopy), and EL serum levels differed significantly between HV and MS patients. The serum levels of triglycerides in large HDL particles were significantly positively correlated with FMD and NMD in HV, but not in MS patients. Cholesterol (C) and phospholipid (PL) contents of large HDL particles, calculated as HDL1-C/HDL1-apoA-I and HDL1-PL/HDL1-apoA-I, respectively, were significantly negatively correlated with FMD in HV, but not in MS patients. Cholesterol efflux capacity and arylesterase activity of HDL, as well as EL, were correlated with neither FMD nor NMD. EL was significantly negatively correlated with HDL-PL/HDL-apoA-I in HV, but not in MS patients, and with serum levels of small dense HDL containing apolipoprotein A-II in MS patients, but not in HV. We conclude that MS modulates the association between HDL and endothelial function, as well as between EL and HDL. HDL cholesterol efflux capacity and arylesterase activity, as well as EL serum levels, are not associated with endothelial function in HV or MS patients.

Advanced Oxidation Protein Products Are Strongly Associated with the Serum Levels and Lipid Contents of Lipoprotein Subclasses in Healthy Volunteers and Patients with Metabolic Syndrome

“…The demographic and clinical characteristics as well as the standard laboratory data of the study groups have been described previously [ 25 , 26 ] and are presented in Tables S1 and S2 . The serum levels of AOPPs were significantly higher in the patients with MS compared to the HVs (HV: 34.6 (28.9, 42.6) μmol/L vs. MS: 41.6 (30.9, 57.3) μmol/L, p = 0.004).…”

“…The study design, laboratory procedures, as well as inclusion and exclusion criteria have been described in our previous reports [ 25 , 26 ]. This study was approved by the local ethics committees of the Sisters of Charity University Hospital Centre, Zagreb, Croatia (EP 13125/17-4); the University of Zagreb, School of Medicine, Croatia; and the Medical University of Graz, Austria (31-532 ex 18/19).…”

Associations between Endothelial Lipase and Apolipoprotein B-Containing Lipoproteins Differ in Healthy Volunteers and Metabolic Syndrome Patients

“…The participants’ demographic and clinical characteristics have been described previously [ 24 ] and are presented in Table 1 . The HV and MS groups did not differ significantly regarding age and sex, body height, smoking status, or presence of a regular menstrual cycle in women.…”

“…The participants’ routine laboratory data have been described previously [ 24 ] and are presented in Table 2 .…”

Special Issue: New Insight into the Molecular Role of Lipids and Lipoproteins in Vascular Diseases

“…EL is an enzyme produced by the endothelium, with seemingly protective effects, such as the regulation of HDL cholesterol levels, and the improvement of the qualitative properties of HDL. Klobucar et al evaluated the association between HDL properties, endothelial function, and serum EL levels in controls and MS patients [ 7 ]. The study found that the presence of MS modulates the association between HDL and endothelial function, as well as between EL and HDL.…”