酒精代謝酶基因多形性與過量酒精攝取對生物體氧化性傷害及抗氧化狀態之研究

Effects of alcohol-metabolizing enzyme polymorphisms and excessive alcohol intake on the oxidative damages and antioxidant status

曾陽明(Yang-Ming Tseng)

指導教授 ： 蔡麗玉

共同指導教授 ： 陳英俊(Ing-Jun Chen)

高雄醫學大學/醫學院/醫學研究所/博士(2009年)

摘要

過量酒精攝取是導致一些慢性或急性疾病相當普遍的危險因子之一，其中的致病機轉包括：因過量酒精攝取致使代謝過程產生過量之活性氧（reactive oxygen species, ROS）及代謝產物—乙醛(acetaldehyde)，造成細胞抗氧化狀態失去平衡而使得諸多疾病因應產生，例如肝功能異常及免疫功能的傷害等。而在這些傷害當中，是否涉及到酒精攝取量的多寡及酒精代謝酶基因的多形性，尚少有人進行這方面的探討。因此本研究的主要目的即：探討酒精代謝酶基因多形性與過量酒精攝取對於生物體之氧化性傷害與抗氧化狀態的研究。
我們分為三階段執行本研究，其中在第一階段實驗，我們先觀察因高血液酒精濃度的急診創傷病人其血液中生化與氧化性傷害指標(丙酮醛malondialdehyde, MDA)及酒精代謝酶基因型是否與一般人有所差異？接著在第二階段實驗中，我們進一步探討酒精攝取量多寡及酒精代謝酶基因多形性與血液中淋巴細胞免疫功能的相關性。而在第三階段，我們參考前二階段實驗結果，分別以細胞培養模式及動物實驗，探討抗氧化物質可能透過那些途徑影響過量酒精造成大白鼠體內氧化性傷害及免疫細胞功能異常。
第一階段結果顯示：急診室中過量飲酒之創傷病患其血液中與肝功能相關的生化指標與氧化性傷害指標－丙酮醛均高於一般健康者，而且其酒精代謝酶基因的變異，尤其是醛脫氫酶（aldehyde dehydrogenase-2, ALDH2），可能是急診室中因過量酒精攝取造成意外事件重要因素之一。而在第二階段實驗結果顯示：於高危險性飲酒者中，其血液中與淋巴球免疫功能相關因子包括：淋巴細胞亞群百分比、部分細胞激素與免疫球蛋白等濃度與低危險性飲酒者有不同程度的差異。最後，在第三階段實驗中，我們發現人類血液免疫細胞（單核球細胞）經適量抗氧化劑-乳漿蛋白濃縮物(whey protein concentrate, WPC)處置後，可藉由提升抗氧化酵素活性及抗氧化物--榖胱甘肽（glutathione, GSH）濃度，來降低過量酒精造成的傷害。而動物實驗部分，我們觀察到過量酒精與WPC同時餵食的大鼠，其脾臟中T細胞呈現增加的現象，相對地B細胞卻呈現下降現象，同時我們觀察到高劑量酒精餵食，會造成大鼠骨髓中B細胞及活化性的T細胞的百分比下降。
總之，過度飲酒及不同的酒精代謝酶基因，可能會影響飲酒者體內氧化還原狀態，此外，過度酒精攝取造成生物體的氧化性傷害，可藉由適當的抗氧化物補充而減緩。因此透過過量酒精造成生物體氧化性傷害機轉的探討，應可提供臨床上，預防與治療因過量酒精攝取導致各組織或細胞氧化性傷害的參考。

關鍵字

酒精 ； 酒精代謝酶多形性 ； 氧化性傷害 ； 抗氧化物

並列摘要

Excessive alcohol intake is a common risk factor for acute and chronic disorders. The causes of cell damage due to excessive alcohol intake are through the overproduction of reactive oxygen species (ROS) or its derivatives, e.g. acetaldehyde, during the process of alcohol metabolism. The ROS and acetaldehyde can result in the imbalance of the antioxidant status and a spectrum of abnormalities in many organs and tissues such as liver disorders and alteration of immunity. However, there are few documented papers investigated in whether individuals are susceptible to alcohol-induced oxidative damage, which is due to the amount of excessive alcohol intake or polymorphisms of alcohol-metabolizing enzymes. The purpose of this study was to investigate the association between the polymorphisms of alcohol-metabolizing enzymes and excessive alcohol intake on the oxidative damage and antioxidants status.
There were three experimental stages in this study. Firstly, we evaluated the relationships between the polymorphisms of alcohol-metabolizing enzymes and the biochemical markers and malondialdehyde (MDA, a biomarker of oxidative damage) in trauma patients with high blood alcohol concentration (BAC) at the emergency department in Kaohsiung Veterans General Hosiptal. Subsequently, we investigated the association between the polymorphisms of alcohol-metabolizing enzymes and the amount of excessive alcohol intake on the immunological functions of lymphocytes. Finally, we adopted the cell culture and animal experiment models to investigate the effects of antioxidants on the alcohol-induced alternations of the immunological functions and oxidative damage.
In the first stage, the levels of MDA and the activities of liver function enzymes in trauma patients with high BAC were higher than those of the control group. In addition, the genetic variations of the alcohol-metabolizing enzymes, especially aldehyde dehydrogenase-2 (ALDH2), may play an important role in the incidents related to excessive alcohol consumption in the emergency department. In the second stage, there were significant differences in the lymphocyte subpopulations and the levels of cytokines and immunoglobulins between the high-risk and low-risk drinkers. In the third stage, the results indicated that PBMC pretreated with whey protein concentrate (WPC) might ameliorate alcohol-induced effects such as imbalance of the antioxidant status by the elevations of glutathione (GSH) levels and the activities of antioxidant enzymes. Meanwhile, there were higher percentages of the T lymphocytes and lower percentages of the B lymphocyte of spleen in rats with alcohol and WPC co-administration than in the control group. Furthermore, there were lower percentages of the B lymphocytes and activated T lymphocytes in rats with alcohol treatment than in the control group.
In conclusion, our results indicated that excessive alcohol intake and genetic variations of alcohol-metabolizing enzymes might be influential markers for susceptibility to alcohol-induced oxidative damage. In addition, the alcohol-induced oxidative damage might be ameliorated by the supplement of antioxidants. Therefore, investigation of the mechanisms of alcohol-induced oxidative damage may clinically provide an effective strategy to prevent and cure alcohol-induced oxidative stress related tissue disorders.

並列關鍵字

alcohol ； alcohol-metabolizing enzyme ； polymorphism ； oxidative damage ； antioxidants

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