Protein metabolism in alcoholism: Effects on specific tissues and the whole body
Protein metabolism in alcoholism: Effects on specific tissues and the whole body
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DOI：
10.1016/s0899-9007(99)00096-9
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发表时间：
1999-07-01
期刊：
影响因子：
4.4
通讯作者：
Peters, TJ
中科院分区：
文献类型：
--
作者：
Preedy, VR;Reilly, ME;Peters, TJ
乙醇是为数不多的具有严重毒性的营养物质之一。酒精会引起全身和组织特异性蛋白质代谢的变化。慢性乙醇滥用增加氮排泄伴随着瘦组织质量的损失。即使是急性剂量的酒精也会引起氮排泄增加。骨骼肌蛋白质的损失（即，慢性酒精性肌病）是对酒精的几种不良反应之一，并且在所有酒精滥用者中高达三分之二的人中发生。还有许多其他疾病和组织异常完全是由于乙醇诱导的单个蛋白质或组织蛋白质组的量的变化;例如，肝硬化中肝胶原蛋白增加，心肌病中肌球蛋白减少，骨质疏松症中骨骼胶原蛋白丢失。乙醇可能在所有器官或组织系统中诱导蛋白质代谢的变化。对无明显肝病的酒精中毒患者的临床研究显示，骨骼肌蛋白质合成速率降低，但全身蛋白质周转似乎没有受到显着影响。然而，酒精滥用者的蛋白质周转研究受到人为的误解，这是由于非禁欲，双重物质滥用（例如，可卡因或烟草）、特定的营养缺乏或存在明显的器官功能障碍。因此，检查酒精对蛋白质代谢影响的最可靠数据来自动物研究，其中可以严格控制给药方案的营养元素。这些研究表明，无论是慢性还是急性，酒精都会导致骨骼肌蛋白质合成减少，以及皮肤，骨骼和小肠的减少。长期而言，动物研究也显示尿氮排泄增加和骨骼肌蛋白损失。对于骨骼肌，蛋白质合成的减少似乎不是由于活性氧的产生，不能用一氧化氮合酶抑制剂阻止，并且可能间接由活性代谢物乙醛介导。骨骼肌蛋白质代谢的变化对全身生理学具有深远的影响，而心脏等器官中的蛋白质周转变化（以蛋白质谱的复杂改变为例）对心血管功能和发病率具有重要意义。(C)Elsevier Science Inc.
Ethanol is one of the few nutrients that is profoundly toxic. Alcohol causes both whole-body and tissue-specific changes in protein metabolism. Chronic ethanol misuse increases nitrogen excretion with concomitant loss of lean tissue mass. Even acute doses of alcohol elicit increased nitrogen excretion. The loss of skeletal muscle protein (i.e., chronic alcoholic myopathy) is one of several adverse reactions to alcohol and occurs in up to two-thirds of all ethanol misusers. There are a variety of other diseases and tissue abnormalities that are entirely due to ethanol-induced changes in the amounts of individual proteins or groups of tissue proteins; for example, increased hepatic collagen in cirrhosis, reduction in myosin in cardiomyopathy, and loss of skeletal collagen in osteoporosis. Ethanol induces changes in protein metabolism in probably all organ or tissue systems. Clinical studies in alcoholic patients without overt liver disease show reduced rates of skeletal muscle protein synthesis though whole-body protein turnover does not appear to be significantly affected. Protein turnover studies in alcohol misusers are, however, subject to artifactual misinterpretations due to non-abstinence, dual substance misuse (e.g., cocaine or tobacco), specific nutritional deficiencies, or the presence of overt organ dysfunction. As a consequence, the most reliable data examining the effects of alcohol on protein metabolism is derived from animal studies, where nutritional elements of the dosing regimen can be strictly controlled. These studies indicate that, both chronically and acutely, alcohol causes reductions in skeletal muscle protein synthesis, as well as of skin, bone, and the small intestine. Chronically, animal studies also show increased urinary nitrogen excretion and loss of skeletal muscle protein. With respect to skeletal muscle, the reductions in protein synthesis do not appear to be due to the generation of reactive oxygen species, are not prevented with nitric oxide synthase inhibitors, and may be indirectly mediated by the reactive metabolite acetaldehyde. Changes in skeletal muscle protein metabolism have profound implications for whole body physiology, while protein turnover changes in organs such as the heart (exemplified by complex alterations in protein profiles) have important implications for cardiovascular function and morbidity. (C) Elsevier Science Inc.