Evaluation of antithrombotic effect: Importance of testing components and methodologies.

The beneficial antithrombotic effect of some dietary components may offer the most promising approach of prevention of cardiovascular diseases and arterial thrombosis. The major stumbling block in finding effective dietary components is the lack of physiologically relevant techniques which can detect potential antithrombotic effect in humans. The presently used platelet function and coagulation tests do not allow the assessment of global thrombotic status and their value in screening dietary components for antithrombotic effect is questionable. Most of these in vitro tests ignore the effect of flow and shear stress, thrombin generation and vascular endothelium, the major contributors to arterial thrombogenesis in humans. As a gold standard, we employed the helium-neon (He-Ne) laser-induced thrombosis test in murine carotid artery and mesenteric microvessels, as the pathomechanism of this test closely reflects arterial thrombogenesis in humans. Results obtained with laser thrombosis test were compared with various shear-induced in vitro platelet function tests which use native blood (Haemostatometry, Thrombotic Status Analyser, Global Thrombosis Test-GTT). Contribution of vascular endothelium to thrombogenesis was assessed by measuring flow-mediated vasodilation (FMV) in vivo. The combination of the two shear-induced ex vivo thrombosis tests (Haemostatometry and GTT) with FMV correlated most closely with the laser-thrombosis test. Our findings suggest that combining the commercially available point-of-care GTT with the FMV test could provide a better assessment of the overall thrombotic status than either of the two tests alone.