engleski

Association of endothelial lipase serum levels with functional characteristics of HDL particles and endothelial dysfunction in patients with metabolic syndrome: an overview of patient clinical data

Introduction: HDL particles maintain normal endothelial function by inducing NO synthesis, inhibiting LDL particles oxidation and reducing adhesion molecules expression on vascular endothelial cells. Endothelial dysfunction is the first, still reversible, step to atherosclerosis and it is present in patients with metabolic syndrome (MS). Serum levels of endothelial lipase, an enzyme which degrades HDL particles, are also elevated in this condition. Hypothesis of this study is that endothelial lipase, through its impact on HDL particle structure and function, induces occurrence of endothelial dysfunction in patients with MS. The aim is to determine association between serum levels of endothelial lipase, serum levels and function of HDL particles and the endothelial dysfunction in patients with MS. Materials and methods: This is an observational, cross-sectional study, recruiting a total of 130 participants (65 healthy volunteers (HV) and 65 patients with MS), held in the University Hospital Centre Sisters of Charity, Zagreb, Croatia, during one year. Patient history and physical examination data are recorded for each participant. A total of 24 ml of venous blood is taken from each participant, centrifuged and serum stored at the temperature of -60°C until the laboratory analysis in the Institute of Molecular Biology and Biochemistry of the Medical University of Graz, Austria. Endothelial dysfunction is quantified with flow- and nitroglycerin-mediated dilation (FMD, NMD) using brachial artery ultrasound (software FloWave.US v. 0.2.0; Coolbaugh CL, Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA). Results: A total of 80 participants (61.5% of the planned number) were enrolled in the study between July 2018 and March 2019, 42 HV and 38 patients with MS. 54.8% of patients in HV group and 44.7% in MS group were female, with no statistically significant difference in sex distribution between the groups (P=0.37). Median age was 57.0 (45-71) for HV group and 57.5 (33-66) years for MS group patients (P=0.78). Compared to HV, patients with MS had significantly higher median systolic blood pressure [125.0 (100-150) mmHg vs. 132.5 (115-160) mmHg; P=0.001], waist circumference [87.0 (72-118) cm vs. 110.5 (84-146) cm; P<0.001], body weight [73.5 (61-125) kg vs. 98.0 (64-146) kg; P<0.001] and body mass index [25.3 (19.4-33.5) kg/m2 vs. 31.4 (22.7-55.6) kg/m2; P<0.001]. In the MS group 86.8% of patients suffered from arterial hypertension, 76.3% had previously known dyslipidaemia and 34.2% of patients had glucose intolerance or diabetes mellitus. Blood sample analyses are ongoing, as well as the analyses of recorded ultrasound materials using software for continuous measurement of brachial artery diameter changes. Exact values for these variables are not available at the moment. Discussion: Presented classification of study participants in HV or MS group is currently based on patient history data about previously known dyslipidaemia and glucose intolerance. The final classification will be done after laboratory blood test analyses completion. There is a possibility that the final data would differ from the currently presented.

endothelial lipase; HDL; endothelial dysfunction

Part of the thesis: Association of endothelial lipase serum levels with functional characteristics of HDL particles and endothelial dysfunction in patients with metabolic syndrome. Research is conducted in cooperation with the Medical University of Graz, Austria (Agreement on cooperation between the Univ. of Zagreb and Medical Univ. of Graz, 2005. Principal investigators: Prof. Saša Frank (Graz) and Prof. Vesna Degoricija (Zagreb)).