Harsfalvi J, Stassen J M, Hoylaerts M F, Van Houtte E, Sawyer R T, Vermylen J, Deckmyn H
Center for Molecular and Vascular Biology, University of Leuven, Belgium.
Blood. 1995 Feb 1;85(3):705-11.
Calin from the saliva of the medicinal leech, Hirudo medicinalis, is a potent inhibitor of collagen mediated platelet adhesion and activation. In addition to inhibition of the direct platelet-collagen interaction, we presently demonstrate that binding of von Willebrand to coated collagen can be prevented by Calin, both under static and flow conditions in agreement with the occurrence of binding of Calin to collagen, confirmed by Biospecific Interaction Analysis. To define whether Calin acted by inhibiting the platelet-collagen or the platelet-von Willebrand factor (vWF)-collagen-mediated thrombus formation, platelet adhesion to different types of collagens was studied in a parallel-plate flow chamber perfused with whole blood at different shear rates. Calin dose-dependently prevented platelet adhesion to the different collagens tested both at high- and low-shear stress. The concentration of Calin needed to cause 50% inhibition of platelet adhesion at high-shear stress was some fivefold lower than that needed for inhibition of vWF-binding under similar conditions, implying that at high-shear stress, the effect of Calin on the direct platelet-collagen interactions, suffices to prevent thrombus formation. Platelet adhesion to extracellular matrix (ECM) of cultured human umbilical vein endothelial cells was only partially prevented by Calin, and even less so at a high-shear rather than a low-shear rate, whereas the platelet binding to coated vWF and fibrinogen were minimally affected at both shear rates. Thus, Calin interferes with both the direct platelet-collagen interaction and the vWF-collagen binding. Both effects may contribute to the inhibition of platelet adhesion in flowing conditions, although the former seems to predominate.
来自药用水蛭（医蛭）唾液的卡林是胶原蛋白介导的血小板黏附和活化的强效抑制剂。除了抑制血小板与胶原蛋白的直接相互作用外，我们目前还证明，在静态和流动条件下，卡林均可阻止血管性血友病因子与包被的胶原蛋白结合，这与卡林与胶原蛋白结合的发生情况一致，生物特异性相互作用分析证实了这一点。为了确定卡林是通过抑制血小板与胶原蛋白的相互作用还是血小板 - 血管性血友病因子（vWF） - 胶原蛋白介导的血栓形成来发挥作用，我们在不同剪切速率下用全血灌注的平行板流动腔中研究了血小板对不同类型胶原蛋白的黏附情况。卡林在高剪切应力和低剪切应力下均呈剂量依赖性地阻止血小板黏附于所测试的不同胶原蛋白。在高剪切应力下导致血小板黏附抑制50%所需的卡林浓度比在类似条件下抑制vWF结合所需的浓度低约五倍，这意味着在高剪切应力下，卡林对血小板与胶原蛋白直接相互作用的影响足以防止血栓形成。卡林仅部分阻止了血小板黏附于培养的人脐静脉内皮细胞的细胞外基质（ECM），在高剪切速率下的阻止作用甚至比低剪切速率下更小，而在两种剪切速率下，血小板与包被的vWF和纤维蛋白原的结合受影响最小。因此，卡林干扰了血小板与胶原蛋白的直接相互作用以及vWF与胶原蛋白的结合。尽管前者似乎占主导地位，但这两种作用可能都有助于在流动条件下抑制血小板黏附。
