WITHDRAWN: Differential Effects of Omega-3 Fatty Acids on HO-1, VCAM-1, and Cytotoxicity in Endothelial Cells

Abstract

<h2>ABSTRACT</h2><h3>Introduction</h3> : Omega-3-fatty acids are considered to have beneficial effects on the initiation and progression of atherosclerosis beyond lowering blood lipids. Clinical trials demonstrated that treatment with high-dose eicosapentaenoic acid (EPA) reduced the incidence of cardiovascular events in at-risk patients, yet not with an EPA and docosahexaenoic acid (DHA) combination treatment. <h3>Objectives</h3> : This <i>in-vitro</i> experiment evaluates molecular mechanisms for the observed differential pleiotropic cardioprotective effects of DHA and EPA on endothelial cells. <h3>Materials and Methods</h3> : Human umbilical vein endothelial cells (HUVEC) were stimulated with 25 ng/ml tumor necrosis factor alpha (TNF-α) and (pre-)treated with 125 µmol/l DHA or EPA. Vascular cell adhesion molecule-1 (VCAM-1) and hemoxygenase-1 (HO-1) mRNA fold change were measured in HUVEC. HUVEC cell viability was determined by MTT assay. <h3>Results</h3> : Pre-treating HUVEC with 125 μmol/l EPA 24 hours before the TNF-α stimulus significantly reduced VCAM-1 mRNA expression by -17.5% (<i>p</i>=.011), yet not DHA (+7.4%, <i>p</i>=.060). Treating HUVEC at the time of the TNF-α stimulus lowered VCAM-1 expression by -22.8% for DHA and -56.7% for EPA (<i>p</i>=.002). Treating HUVEC simultaneous to the TNF-α stimulus increased HO-1 expression for DHA (+571.4%, <i>p</i>=.007) and EPA (+581.4%, <i>p</i>=.003). Repeated treatment of HUVEC with DHA or EPA further reduced VCAM-1 expression, whilst HO-1 expression surged by +3,133.4% for DHA and +919.1% for EPA (<i>p</i>=.002). MTT assays displayed DHA and EPA were cytotoxic on HUVEC beyond concentrations of 250 µmol/l. <h3>Conclusions</h3> : (Pre-)treatment of HUVEC with EPA reduces VCAM-1 expression, which is known to impact the initiation and progression of arteriosclerosis, to a greater extent than DHA. In contrast, DHA displays a greater effect on HO-1 expression than EPA. These results offer potential molecular mechanisms for the clinically observed different pleiotropic effects in cardiometabolic treatment of omega-3 fatty acids.