Effect of fatty acids on expression of endothelial leukocyte adhesion molecules

With respect to linoleic acid both beneficial and proatherogenic effects have been described. However, the effect on expression of cell adhesion molecules on human coronary artery endothelial cells (HCAEC) is not yet established. The aim of the experiments was to evaluate the influence of linoleic acid in comparison with palmitic acid regarding the cytokine-induced expression of endothelial leukocyte adhesion molecules (intercellular cell adhesion molecule-1 ICAM-1, vascular cell adhesion molecule-1 VCAM-1, E-selectin).

HCAEC were cultured in microvascular endothelial cell growth medium. In the experiments, the cells were preincubated with linoleic acid and palmitic acid, respectively (10 micro mol/l, 2 days) or under control conditions, after which interleukin- 1alpha (IL-1alpha, 10 ng/ml in the test medium) was added for 1 day. The monoclonal antibodies used were fluorescein isothiocyanate (FITC)- labeled anti-ICAM-1, FITC-labeled anti-VCAM-1, and FITC-labeled anti-E-selectin. Expression was analyzed by flow cytofluorimetry. Next, to examine the effects of fatty acids on adhesion of monocytes to endothelial cells, adhesion experiments with the monocytic U 937 cell line were performed.

IL-1alpha increased ICAM-1,VCAM-1, and E-selectin expression compared to controls. Incubation with IL-1alpha together with linoleic acid reduced the expression of ICAM-1 and VCAM-1 in contrast to palmitic acid. Furthermore, in the presence of linoleic acid a tendency of diminished adhesion of monocytes is seen. The results indicate that a reduced expression of cell adhesion molecules may be relevant to the antiatherogenic effects of linoleic acid. This is in contrast to the properties of palmitic acid.