Steiner M, Li W
Division of Hematology/Oncology, East Carolina University School of Medicine, Greenville, NC 27858-4354, USA.
J Nutr. 2001 Mar;131(3s):980S-4S. doi: 10.1093/jn/131.3.980S.
Aged garlic extract (AGE) has been shown previously to have moderate cholesterol-lowering and blood pressure-reducing effects. We have now investigated whether platelet function, a potential risk factor for cardiovascular disease, can be inhibited by AGE administration. In a randomized, double-blind study of normal healthy individuals (n = 34), both men and women, the effect of AGE was evaluated in doses between 2.4 and 7.2 g/d vs. equal amounts of placebo. Platelet aggregation and adhesion were measured at 2-wk intervals throughout the study. Threshold concentrations for epinephrine and collagen increased moderately during AGE administration compared with the placebo and baseline periods. Only at the highest supplementation level did AGE show a slight increase in the threshold level of ADP-induced aggregation. Platelet adhesion to collagen, fibrinogen and von Willebrand factor was investigated by perfusing whole blood through a laminar flow chamber under controlled flow conditions. Adherence of platelets was inhibited by AGE in a dose-dependent manner when collagen was the adhesive surface perfused at low shear rates ( approximately 30 s(-1)). At high shear rates (1200 s(-1)), AGE also inhibited platelet adhesion to collagen but only at higher intake levels. Adhesion to von Willebrand factor was reduced only at 7.2 g/d AGE, but adherence to fibrinogen was potently inhibited at all levels of supplementation. Thus, AGE exerts selective inhibition on platelet aggregation and adhesion, platelet functions that may be important for the development of cardiovascular events such as myocardial infarction and ischemic stroke. We briefly review the effect of garlic preparations in general on cardiovascular risk factors and point out differences between AGE and other garlic preparations that we feel are important to explain the efficacy of AGE.
先前的研究表明， aged garlic extract (AGE) 具有适度的降低胆固醇和血压的作用。我们现在研究了AGE给药是否能抑制血小板功能，血小板功能是心血管疾病的一个潜在危险因素。在一项针对正常健康个体（n = 34）的随机双盲研究中，评估了2.4至7.2 g/d剂量的AGE与等量安慰剂对男性和女性的影响。在整个研究过程中，每隔2周测量一次血小板聚集和黏附情况。与安慰剂期和基线期相比，AGE给药期间肾上腺素和胶原蛋白的阈值浓度适度增加。仅在最高补充水平时，AGE才显示出ADP诱导聚集阈值水平略有增加。通过在可控流动条件下使全血通过层流室来研究血小板与胶原蛋白、纤维蛋白原和血管性血友病因子的黏附。当胶原蛋白作为低剪切速率（约30 s(-1)）下灌注的黏附表面时，AGE以剂量依赖性方式抑制血小板黏附。在高剪切速率（1200 s(-1)）下，AGE也抑制血小板与胶原蛋白的黏附，但仅在较高摄入量水平时。仅在7.2 g/d的AGE剂量下，与血管性血友病因子的黏附减少，但在所有补充水平下，与纤维蛋白原的黏附均受到有效抑制。因此，AGE对血小板聚集和黏附具有选择性抑制作用，而血小板功能可能对心肌梗死和缺血性中风等心血管事件的发生很重要。我们简要回顾了大蒜制剂一般对心血管危险因素的影响，并指出了AGE与其他大蒜制剂之间的差异，我们认为这些差异对于解释AGE的疗效很重要。
