8-HYDROXYDEOXYGUANOSINE AS A URINARY BIOMARKER OF OXIDATIVE DNA-DAMAGE
8-HYDROXYDEOXYGUANOSINE AS A URINARY BIOMARKER OF OXIDATIVE DNA-DAMAGE
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DOI：
10.1080/15287399309531806
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发表时间：
1993-10-01
期刊：
影响因子：
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通讯作者：
POULSEN, HE
中科院分区：
文献类型：
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作者：
LOFT, S;FISCHERNIELSEN, A;POULSEN, HE
由于生化反应和外界因素的影响，生物体不断地暴露在活性氧物种中。氧化DNA损伤与衰老、癌症和其他退行性疾病有关。尿中DNA修复产物8-羟基脱氧鸟苷(8OHdG)的排泄被认为是体内DNA氧化损伤的非侵入性生物标志物。我们建立了一种用于分析尿中8OHdG的三维高效液相色谱分析和电化学检测方法，并研究了83名健康人和各种实验动物(包括狗、猪和大鼠)中这一生物标志物排泄的影响因素。此前，其他研究小组曾使用类似的高效液相色谱方法或带有选择性离子监测的气相色谱-质谱仪来测量人类、大鼠、小鼠和猴子体内80HdG的排泄量。到目前为止，在169名受试者中，8OHdG的平均排泄量为每24小时200-300pmol/kg，范围为7倍，变异系数为30-40%。这种排泄相当于每个细胞每天140-200个鸟嘌呤碱基的氧化修饰。我们研究人群中的32名吸烟者比53名不吸烟者多排出50%(31-69%；95%的可信区间)的8OHdG。这表明吸烟导致的氧化DNA损伤率增加了约10%，增加了吸烟对健康的其他众所周知的危害。生化-生理学基础尚不清楚，但可能与烟雾成分有关，包括或产生活性氧物种和/或消耗抗氧化剂和/或众所周知的吸烟对代谢率的促进作用。在83名健康受试者中，8OHdG排泄量与身体成分相关。因此，瘦身和/或男性受试者的排泄量高于肥胖和/或女性受试者，这可能与代谢率的差异有关。相应地，限制热量摄入后，8OHdG的排泄量减少，这将导致代谢率下降。在被调查的物种中，人类、狗、猪和大鼠的8OHdG排泄量与特定代谢率相关，证实了来自其他群体的关于人类、猴子、大鼠和小鼠的数据。大鼠8OHdG排泄量随增龄而减少，代谢率随增龄而下降。8OHdG的排泄反映了所描述的大约20个DNA氧化修饰中只有一个的形成和修复。到目前为止，除了8OHdG和胸苷乙醇外，还没有检测尿液中相应修复产物的方法。此外，在突变方面的重要性，特别是关于肿瘤抑制基因和癌基因，主要是在DNA中记录的8OHdG。在哺乳动物细胞中，已经证实了8OHdG的裂解修复酶复合体，但主要产物是8OHdG还是碱基尚不清楚。此外，8OHdG可能来自线粒体和细胞周转过程中的DNA，以及为新DNA提供构件的脱氧核苷酸和脱氧核苷池中的氧化。因此，8OHdG的排泄量将反映所有组织和器官DNA中致突变氧化加合物的总体平均风险。我们认为，人类明显的大规模DNA氧化损伤程度的个体差异可以预测衰老速度、癌症和其他退行性疾病的风险。8OHdG和类似的氧化DNA损伤尿液生物标记物的使用为在人类身上检验这种假说提供了一个有价值的工具。
Living organisms are continuously exposed to reactive oxygen species as a consequence of biochemical reactions as well as external factors. Oxidative DNA damage has been implicated in aging, carcinogenesis and other degenerative diseases. The urinary excretion of the DNA repair product 8-hydroxydeoxyguanosine (8OHdG) has been proposed as a noninvasive biomarker of oxidative DNA damage in humans in vivo. We have developed a three-dimensional HPLC analysis with electrochemical detection for the analysis of 8OHdG in urine and studied factors affecting the excretion of this biomarker in 83 healthy humans and in various laboratory animals, including dog, pig, and rat. Previously, other groups have used comparable HPLC methods or gas chromatography-mass spectrometry with selective ion monitoring for measuring the excretion of 8OHdG in humans, rats, mice, and monkeys. In the 169 humans studied so far, the average 8OHdG excretion was 200-300 pmol/kg per 24 h with a sevenfold range, and the coefficient of variation was 30-40%. This excretion corresponds 140-200 oxidative modification of guanine bases per cell per day. Thirty-two smokers from our study population excreted 50% (31-69%; 95% confidence interval) more 8OHdG than 53 nonsmokers. This indicates a SO% increased rate of oxidative DNA damage from smoking, adding to the other well-known health hazards of smoking. The biochemical-physiological basis is unknown but may be related to smoke constituents including or generating reactive oxygen species and/or consuming antioxidants and/or the well-known enhancing effect of smoking on the metabolic rate. In our 83 healthy subjects the 8OHdG excretion correlated with body composition. Thus, lean and/or male subjects excreted more than obese and/or female subjects, possibly related to differences in metabolic rate. In accordance, the excretion of 8OHdG decreased after calorie restriction, which will cause a decline in the metabolic rate. Across the investigated species, humans, dogs, pigs, and rats, the excretion of 8OHdG correlated with the specific metabolic rate, confirming data from other groups on humans, monkeys, rats, and mice. The excretion of 8OHdG decreased with age in rats in parallel with the decline in metabolic rate with advancing age. The excretion of 8OHdG reflects the formation and repair of only one out of approximately 20 described oxidative DNA modifications. So far, methods are not available for the determination of the corresponding repair products, except 8OHdG and thymidine glycol, in urine. Moreover, the importance in terms of mutagenicity, particularly regarding tumour supressor genes and oncogenes, is mainly documented for 8OHdG in DNA. In mammalian cells an excission repair enzyme complex for 8OHdG has been demonstrated, but whether the main product is 8OHdG or the base is yet unknown. In addition, 8OHdG may derive from DNA during turnover of mitochondria and cells as well as from oxidation in the deoxynucleotide and deoxynucleoside pools that provide building blocks for new DNA. Thus, the excretion of 8OHdG will reflect the general average risk of promutagenic oxidative adducts in DNA of all tissues and organs. We suggest that the individual variation in the apparent massive extent of oxidative DNA-damage in humans predicts the rate of aging and the risk of cancer as well as other degenerative diseases. The use of 8OHdG and similar urinary biomarker of oxidative DNA damage offers a valuable tool for testing such hypotheses in humans.