Foster M R, Hornby E J, Brown S, Hann M, Kitchin J, Pike N, Ward P
Department of Cardiovascular, Glaxo Group Research Limited, Ware, Herts.
Thromb Res. 1994 Aug 1;75(3):269-84. doi: 10.1016/0049-3848(94)90238-0.
In order to produce more potent and specific fibrinogen receptor (GpIIb/IIIa) antagonists, the Arg-Gly of a chemical series based upon Arg-Gly-Asp was replaced by alkyl chains of varying lengths. The most potent in this series, GR91669, inhibited aggregation of human gel-filtered platelets (GFP) in vitro induced by ADP or the thromboxane A2 mimetic, U46619, with IC50 values of 200nM and 500nM respectively and was selected for further studies. Its inhibitory effects on GFP were reversed by addition of excess fibrinogen. The compound also inhibited ADP- or U46619-induced platelet aggregation in human whole blood (IC50 values of 700nM in both cases). 125I-Fibrinogen binding to ADP-stimulated platelets was inhibited by GR91669 with an IC50 (65nM) similar to that against platelet aggregation. GR91669 (1mM) did not inhibit U46619-induced platelet shape change or 14C-5HT secretion from platelets stimulated by collagen, U46619 or thrombin. Therefore GR91669 inhibits aggregation but has no significant effect on stimulus-response events, a profile consistent with fibrinogen receptor blockade. In addition, GR91669 (1mM), unlike echistatin or Gly-Arg-Gly-Asp-Ser, did not disrupt vitronectin recptor-dependent attachment of cultured HUVECS in vitro and similarly did not inhibit Mac-1 dependent adhesion of human granulocytes. Thus, of the integrins tested, GR91669 appears to be specific for GpIIb/IIIa. Following intravenous administration to marmosets of 1 or 10 mg/kg GR91669, ADP (10 microM)-induced platelet aggregation ex vivo was abolished for 15 and 60 minutes respectively. Greater than 50% inhibition was maintained for 30 minutes and 2 hours respectively. GR91669, therefore appears to be a potent, specific fibrinogen receptor antagonist in vitro and which is also active in vivo.
为了生产出更有效且更具特异性的纤维蛋白原受体（糖蛋白IIb/IIIa）拮抗剂，基于精氨酸-甘氨酸-天冬氨酸（Arg-Gly-Asp）的一系列化合物中的精氨酸-甘氨酸被不同长度的烷基链取代。该系列中最有效的化合物GR91669，在体外可抑制由二磷酸腺苷（ADP）或血栓素A2类似物U46619诱导的人凝胶过滤血小板（GFP）聚集，其半数抑制浓度（IC50）值分别为200nM和500nM，并被选作进一步研究。加入过量纤维蛋白原可逆转其对GFP的抑制作用。该化合物还可抑制人全血中ADP或U46619诱导的血小板聚集（两种情况下IC50值均为700nM）。GR91669可抑制125I-纤维蛋白原与ADP刺激的血小板结合，其IC50（65nM）与对血小板聚集的抑制作用相似。GR91669（1mM）不抑制U46619诱导的血小板形状改变，也不抑制由胶原、U46619或凝血酶刺激的血小板分泌14C-5-羟色胺（5HT）。因此，GR91669抑制聚集，但对刺激-反应事件无显著影响，这一特征与纤维蛋白原受体阻断一致。此外，与echistatin或甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸（Gly-Arg-Gly-Asp-Ser）不同，GR91669（1mM）在体外不会破坏培养的人脐静脉内皮细胞（HUVECS）的玻连蛋白受体依赖性黏附，同样也不抑制人粒细胞的Mac-1依赖性黏附。因此，在所测试的整合素中，GR91669似乎对糖蛋白IIb/IIIa具有特异性。给狨猴静脉注射1mg/kg或10mg/kg GR91669后，体外由ADP（10μM）诱导的血小板聚集分别在15分钟和60分钟内被消除。分别在30分钟和2小时内维持大于50%的抑制作用。因此，GR91669在体外似乎是一种有效的、特异性的纤维蛋白原受体拮抗剂，并且在体内也具有活性。
