Deckmyn H, Stassen J M, Vreys I, Van Houtte E, Sawyer R T, Vermylen J
Center for Molecular and Vascular Biology, University of Leuven, Belgium.
Blood. 1995 Feb 1;85(3):712-9.
Interaction between exposed collagen and platelets and/or von Willebrand factor is believed to be one of the initiating events for thrombus formation at sites of damaged endothelium. Interference with this mechanism may provide an anti-thrombotic potential. Calin, a product from the saliva of the leech Hirudo medicinalis, was tested in vitro and for its in vivo activity in a thrombosis model in hamsters. Calin specifically and dose dependently (IC50:6.5 to 13 micrograms/mL) inhibited human platelet aggregation induced by collagen. In addition, specific platelet adhesion onto microtiter wells coated with collagen and detected with a monoclonal antiglycoprotein IIb/IIIa antibody-conjugated with horseradish peroxidase, could be completely prevented with Calin (IC50:22 micrograms/mL). A dose-response curve was constructed in groups of six hamsters in whom a standardized trauma was induced on the femoral vein. Thrombus formation was followed continuously using video recording and processing of the image obtained upon transillumination of the vessel. Intravenous Calin dose-dependently inhibited platelet-rich thrombus formation in this model with an ED50 of 0.07 mg/kg and complete inhibition with 0.2 mg/kg. No effects were seen on coagulation tests or bleeding times, whereas ex vivo aggregation induced by collagen was inhibited dose dependently. Local application of leech saliva, Calin, hirudin, or the combination of the latter two into the bleeding time wound of hamsters resulted in a mild prolongation of the bleeding time (twofold to threefold). A similar experiment in baboons did not cause any prolongation of the bleeding time. This is in sharp contrast with the long-lasting bleeding after a leech bite itself in both species. Calin from the leech Hirudo medicinalis is able, by binding to collagen, to effectively interfere with platelet-collagen interaction, which results in an antithrombotic effect observed in a platelet-rich thrombosis model in hamsters.
暴露的胶原蛋白与血小板和/或血管性血友病因子之间的相互作用被认为是受损内皮部位血栓形成的起始事件之一。干扰这一机制可能具有抗血栓形成的潜力。水蛭（医用水蛭）唾液中的产物卡林（Calin）在体外以及在仓鼠血栓形成模型中进行了体内活性测试。卡林能特异性且剂量依赖性地（半数抑制浓度：6.5至13微克/毫升）抑制胶原蛋白诱导的人血小板聚集。此外，用与辣根过氧化物酶偶联的单克隆抗糖蛋白IIb/IIIa抗体检测到的血小板在包被胶原蛋白的微量滴定板上的特异性黏附，可被卡林完全阻止（半数抑制浓度：22微克/毫升）。在六组仓鼠中构建剂量反应曲线，在其股静脉上诱导标准化创伤。通过视频记录和对血管透照获得的图像进行处理来连续跟踪血栓形成。在该模型中，静脉注射卡林剂量依赖性地抑制富含血小板的血栓形成，半数有效剂量为0.07毫克/千克，0.2毫克/千克时完全抑制。对凝血试验或出血时间无影响，而胶原蛋白诱导的体外聚集呈剂量依赖性抑制。将水蛭唾液、卡林、水蛭素或后两者的组合局部应用于仓鼠的出血时间伤口，导致出血时间轻度延长（两倍至三倍）。在狒狒身上进行的类似实验未导致出血时间延长。这与两个物种自身被水蛭叮咬后长时间出血形成鲜明对比。来自医用水蛭的卡林能够通过与胶原蛋白结合，有效干扰血小板 - 胶原蛋白相互作用，这在仓鼠富含血小板的血栓形成模型中观察到具有抗血栓作用。
