Effect of oat and barley β-glucans on inhibition of cytokine-induced adhesion molecule expression in human aortic endothelial cells: Molecular structure-function relations

Endothelial cell adhesion molecules have been recognized as an early step in inflammation and atherogenesis. The inhibition of TNF-alpha-induced expression of vascular cell adhesion molecule (VCAM-1) and intracellular cell adhesion molecule (ICAM-1) in human aortic endothelial cells (HAEC), following pretreatment with mixed-linkage (1 -> 3),(1 -> 4)-beta-D-glucans (beta-glucans) isolated from oat and barley, and the possible molecular structure-function relations, have been explored. The apparent molecular weight (Mw) of beta-glucans varied in the ranges of 0.71-2.42 x 10(5) (barley) and 0.36-2.55 x 10(5) (oat); a higher ratio of 3-O-beta-cellobiosyl-D-glucose to 3-O-beta-cellotriosyl-D-glucose oligomers in the polymeric chains was also found for barley beta-glucans. Analysis of variance showed that polysaccharide concentration, Mw and fine structure of beta-glucans affected the VCAM-1 expression (P<0.05); the reduction of VCAM-1 expression in stimulated HAEC was also dose-dependent (concentration range of 3.75-200 mu g/ml beta-glucans) and significant at polysaccharide levels >6.25 mu g/ml(P<0.05). The inhibition of VCAM-1 expression was greater for barley beta-glucans compared to oat, displaying a maximum anti-inflammatory activity at Mw similar to 1.40 x 10(5). Instead, the expression of ICAM-1 was suppressed (P<0.05) only at high polysaccharide concentrations (>100 mu g/ml), with maximum activity at Mw similar to 2.50 x 10(5). Structural differences between the oat and barley beta-glucans did to seem to influence the ICAM-1 expression. (C) 2010 Elsevier Ltd. All rights reserved.