NOVEL INHIBITORS OF THROMBIN

使用称为“适体”的新型体外选择/扩增技术， 技术”，我们已经确定了一类新的凝血酶抑制剂， 在单链DNA（ssDNA）寡核苷酸上（Bock等，Nature 355， 564-6，1992）。一种寡核苷酸GGTTGGTGTGGTTGG（凝血酶适体）， 在体外和体内显示出强的抗凝活性。药理 在食蟹猴中的研究显示凝血酶适体具有快速的 起效快，体内半衰期短。体内半衰期短 允许体外血液滤过的局部抗凝 绵羊回路，犬成功抗凝 体外循环模型该项目的具体目标是：1） 评估凝血酶适体作为犬抗凝剂的有效性 和灵长类动物的心肺转流模型，这将证明使用 鱼精蛋白硫酸盐，并可能减少血液制品的使用; 2）测试 凝血酶适体作为非人局部抗凝剂的功效 灵长类动物血液透析，可最大限度地减少与 全身抗凝; 3）开发具有成本效益的、大规模的 凝血酶适体的制造方法。我们的最终目标是 开发这种新型的基于ssDNA的凝血酶适体作为抗凝剂 上级于肝素，用于心肺转流和血液透析， III期临床试验。

Using a novel in vitro selection/amplification technique termed "aptamer technology", we have identified a new class of thrombin inhibitors based on single-stranded DNA (ssDNA) oligonucleotides (Bock et al. Nature 355, 564-6, 1992). One oligonucleotide GGTTGGTGTGGTTGG (thrombin aptamer), showed potent anticoagulant activity in vitro and in vivo. Pharmacological studies in cynomolgus monkeys showed the thrombin aptamer to have a rapid onset of action and short half-life in vivo. The short in vivo half-life permitted regional anticoagulation of an extracorporaal hemofiltration circuit in sheep, and successful anticoagulation in a canine cardiopulmonary bypass model. The specific aims of this project are: 1) To assess the efficacy of the thrombin aptamer as an anticoagulant in canine and primate models of cardiopulmonary bypass which will obviate the use of protamine sulfate and may reduce the use of blood products; 2) To test the efficacy of the thrombin aptamer as a regional anticoagulant in non-human primate hemodialysis which may minimize the bleeding risks associated with systemic anticoagulation; 3) To develop a cost efficient, large scale manufacturing process for the thrombin aptamer. Our ultimate goal is to develop this novel ssDNA based thrombin aptamer as an anticoagulant superior to heparin for use in cardiopulmonary bypass and hemodialysis in Phase III clinical trials.