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RESEARCH PRODUCT

Erythrocyte-associated apolipoprotein B and its relationship with clinical and subclinical atherosclerosis

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Eur J Clin Invest 2012; 42 (4): 365–370 Abstract Background  Apolipoprotein (apo) B-containing lipoproteins are closely linked to atherogenesis. These lipoproteins are transported in plasma and are also associated with blood leucocytes. Our aim was to investigate whether apoB-containing lipoproteins are also present on the surface of erythrocytes and investigate the relationship with the presence of atherosclerosis in a cross-sectional study. Materials and methods  Erythrocyte-bound apoB (ery-apoB) was measured by flowcytometry in subjects with (CAD+) and without coronary artery disease (CAD−), based on coronary angiography or on a history of cardiovascular disease. Intima media thickness (IMT) measurements were carried out using B-mode ultrasound. The relationship between ery-apoB and clinical and subclinical atherosclerosis was evaluated with binary logistic regression. Results  A total of 166 subjects were included (40 CAD+ and 126 CAD−). ApoB was detected on freshly isolated erythrocytes (range: 0·1–5·5 au; mean ± SEM 0·86 ± 0·09 au) in all but nine subjects (four CAD+ and five CAD−). Ery-apoB was lower in CAD+ (0·62 ± 0·09 au) compared to CAD− (1·18 ± 0·10 au; P < 0·001). Higher ery-apoB was associated with a lower risk of CAD (adjusted OR: 0·003 (95% CI: 0·001–0·08; P < 0·001), but the protective effect was diminished with increasing age (adjusted OR: 1·10 (95% CI: 1·04–1·16; P < 0·001). IMT was increased in CAD+ subjects (0·77 ± 0·13 mm) compared to CAD− (0·57 ± 0·14 mm; P < 0·001). A significant negative association was found between ery-apoB and IMT (β = −0·214: 95% CI −0·284 to −0·145; P < 0·001). There was no association between ery-apoB and plasma apoB (Pearson’s r = −0·45; P = 0·57). Conclusions  Human erythrocytes carry apoB-containing lipoproteins. Subjects with atherosclerosis have lower ery-apoB. High ery-apoB may be protective against atherosclerosis and may reflect an alternative blood cell–mediated lipoprotein transport system in the circulation, in which these lipoproteins less likely interact with the endothelium.