Steinberg D
University of California, San Diego, La Jolla, California 92093-0682, USA.
Curr Opin Lipidol. 2000 Dec;11(6):603-7. doi: 10.1097/00041433-200012000-00006.
In-vitro studies and animal model studies provide an ever-growing body of evidence, direct and indirect, that oxidation of low-density lipoprotein and/or related oxidative mechanisms play a role in atherogenesis. However, two recent, very large, carefully conducted clinical intervention trials using adequate doses of vitamin E demonstrated no effect on a composite end-point of non-fatal infarction, stroke or death from cardiovascular causes. Why the unexpected negative results? Possibly because the animal intervention evidence on which these trials were based deals primarily with very early lesions (fatty streaks). That evidence does not necessarily provide a basis for predicting what antioxidant intervention will do in patients with advanced lesions, particularly when the end-points used relate to unstable plaques and fatal thrombosis, events for which we have no adequate animal models. Nor does it necessarily follow that the same antioxidants used successfully in animals will be effective in humans. The strength of the evidence for the oxidative modification hypothesis is such that negative clinical trials with one particular antioxidant, in patients with very advanced coronary heart disease and lasting only 3-5 years, should not be taken as refutation of the hypothesis. Perhaps different kinds of human trials are needed, trials in which the development of new lesions is measured, in order to test whether antioxidants can decrease the rate of initiation and early progression of atherosclerosis as they do in animals. The answer to the title query is 'Probably, but it is too soon to say'.
体外研究和动物模型研究提供了越来越多的直接和间接证据,表明低密度脂蛋白的氧化和/或相关氧化机制在动脉粥样硬化形成中起作用。然而,最近两项使用足够剂量维生素E精心开展的大型临床干预试验表明,对非致命性心肌梗死、中风或心血管疾病死亡的复合终点没有影响。为什么会出现意外的阴性结果呢?可能是因为这些试验所依据的动物干预证据主要涉及非常早期的病变(脂肪条纹)。该证据不一定能为预测抗氧化剂干预对晚期病变患者的效果提供依据,特别是当所使用的终点与不稳定斑块和致命性血栓形成相关时,而对于这些情况我们没有合适的动物模型。也不一定意味着在动物身上成功使用的相同抗氧化剂在人类身上也会有效。氧化修饰假说的证据力度很强,对于患有非常严重冠心病且仅持续3至5年的患者,使用一种特定抗氧化剂的阴性临床试验不应被视为对该假说的反驳。或许需要进行不同类型的人体试验,即测量新病变发展情况的试验,以测试抗氧化剂是否能像在动物身上那样降低动脉粥样硬化的起始和早期进展速率。标题问题的答案是“可能,但现在说还为时过早”。