Hsiao George, Lee Jie J, Lin Kuang H, Shen Chia H, Fong Tsorng H, Chou Duen S, Sheu Joen R
Graduate Institute of Pharmacology, Taipei Medical University, Taipei, Taiwan.
Cardiovasc Res. 2007 Sep 1;75(4):782-92. doi: 10.1016/j.cardiores.2007.05.005. Epub 2007 May 10.
Caffeic acid phenethyl ester (CAPE), which is derived from the propolis of honeybee hives, has been demonstrated to possess multiple pharmacological activities. In the present study, CAPE (6-25 microM) specifically inhibited collagen-induced platelet aggregation and the ATP release reaction in platelet suspensions.
Platelet aggregation, flow cytometric analysis, immunoblotting, and electron spin resonance (ESR) were used to assess the anti-platelet activity of CAPE. Fluorescein sodium-induced platelet thrombi in mesenteric microvessels of mice were used for an in vivo study.
CAPE (15-100 microM) produced a concentration-related rightward displacement of the collagen concentration-response curve, and the Schild plot gave pA(2) and pA(10) values of 4.28+/-0.07 and 3.14+/-0.73, respectively, with a slope of -0.83+/-0.16, indicating specific antagonism. CAPE (25 microM) also inhibited platelet aggregation stimulated by the glycoprotein VI agonist, convulxin, and the alpha(2)beta(1) integrin agonist, aggretin. CAPE (25 microM) also markedly interfered with FITC-collagen binding to platelet membranes. CAPE (15 and 25 microM) concentration-dependently inhibited collagen-induced platelet activation accompanied by Ca(+2) mobilization, phosphoinositide breakdown, activation of protein kinase C and mitogen-activated protein kinases (i.e., ERK2, JNK, and p38 MAPK), Akt phosphorylation, and thromboxane A(2) formation. In the ESR study, CAPE (15 and 25 microM) markedly reduced hydroxyl radical (OH) formation in collagen-activated platelets. In an in vivo study, CAPE (5 mg/kg) significantly prolonged the latency in inducing platelet plug formation in mesenteric venules of mice.
The most important findings of this study suggest that CAPE specifically inhibits collagen-induced platelet activation. Thus, CAPE treatment may represent a novel approach to lowering the risk of or improving function in thromboembolism-related disorders.
咖啡酸苯乙酯（CAPE）源自蜜蜂蜂巢的蜂胶，已被证明具有多种药理活性。在本研究中，CAPE（6 - 25微摩尔）特异性抑制胶原诱导的血小板聚集以及血小板悬液中的ATP释放反应。
采用血小板聚集、流式细胞术分析、免疫印迹和电子自旋共振（ESR）来评估CAPE的抗血小板活性。利用荧光素钠诱导小鼠肠系膜微血管中的血小板血栓进行体内研究。
CAPE（15 - 100微摩尔）使胶原浓度 - 反应曲线产生浓度相关的右移，Schild图给出的pA(2)和pA(10)值分别为4.28±0.07和3.14±0.73，斜率为 - 0.83±0.16，表明为特异性拮抗作用。CAPE（25微摩尔）还抑制糖蛋白VI激动剂convulxin和α(2)β(1)整合素激动剂aggretin刺激的血小板聚集。CAPE（25微摩尔）也显著干扰FITC - 胶原与血小板膜的结合。CAPE（15和25微摩尔）浓度依赖性地抑制胶原诱导的血小板活化，伴有[Ca(+2)]i动员、磷酸肌醇分解、蛋白激酶C和丝裂原活化蛋白激酶（即ERK2、JNK和p38 MAPK）的活化、Akt磷酸化以及血栓素A(2)的形成。在ESR研究中，CAPE（15和25微摩尔）显著减少胶原活化血小板中羟基自由基（OH）的形成。在体内研究中，CAPE（5毫克/千克）显著延长小鼠肠系膜小静脉中诱导血小板栓形成的潜伏期。
本研究最重要的发现表明，CAPE特异性抑制胶原诱导的血小板活化。因此，CAPE治疗可能代表一种降低血栓栓塞相关疾病风险或改善其功能的新方法。
