Summary

An increased erythrocyte aggregation (EA) is associated withcapillary slow flow, tissue hypoxemia and endothelial dysfunction.Fibrinogen is a major determinant in the formation of aggregatedred blood cells. It has been suggested that the B ß -fibrinogen–455G/A polymorphism is associated with erythrocytehyperaggregability in men with coronary artery disease.The purposeof this study was to investigate the influence of the ß -fibrinogen–455G/A polymorphism on erythrocyte aggregation inapparently healthy individuals. Plasma fibrinogen, red blood cellcount, serum lipids, erythrocyte sedimentation rate, and the genotypeof the B ß -fibrinogen –455G/A polymorphism wereexamined in a cohort of 545 apparently healthy individuals andthose with atherothrombotic risk factors.A whole blood erythrocyteaggregation test was performed by using a simple slide test and image analysis. In men, EA levels and plasma fibrinogenlevels were significantly higher in subjects carrying the –455A allelecompared to subjects with the –455 GG genotype.This associationdid not exist in women carrying the fibrinogen –455Aallele.The –455GA/AA men presented significantly higher correlationbetween the plasma fibrinogen concentrations and EA.This observation raises the prospect of possible change in thefunctional properties of the –455GA/AA fibrinogen, enhancingits ability to induce EH. This study suggests that the B ß -fibrinogen–455A allele is related to EH in men only. Putative mechanismcould be hyperfibrinogenemia and a functional change inthe fibrinogen molecule that alters its ability to interact with redblood cells and supports the aggregability of these cells.