Review
Urinary 8-OHdG: a marker of oxidative stress to DNA and a risk factor for cancer, atherosclerosis and diabetics

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Abstract

Reactive oxygen species (ROS) produced either endogenously or exogenously can attack lipid, protein and nucleic acid simultaneously in the living cells. In nuclear and mitochondrial DNA, 8-hydroxydeoxyguanosine (8-OHdG), an oxidized nucleoside of DNA, is the most frequently detected and studied DNA lesion. Upon DNA repair, 8-OHdG is excreted in the urine. Numerous evidences have indicated that urinary 8-OHdG not only is a biomarker of generalized, cellular oxidative stress but might also be a risk factor for cancer, atherosclerosis and diabetes. For example, elevated level of urinary 8-OHdG has been detected in patients with various cancers. In human atherosclerotic plaques, there were increased amounts of oxidatively modified DNA and 8-OHdG. Elevated urinary 8-OHdG and leukocyte DNA were also detected in diabetic patients with hyperglycemia, and the level of urinary 8-OHdG in diabetes correlated with the severity of diabetic nephropathy and retinopathy. We have discussed various methods for determining 8-OHdG in the tissue and urine, including HPLC with and without extraction, and ELISA. Using the ELISA we developed, we found that the normal range of urinary 8-OHdG for females was 43.9±42.1 ng/mg creatinine and 29.6±24.5 ng/mg creatinine for males, respectively. We found that the normal value between females and males is significantly different (p<0.001).

Introduction

In living cells reactive oxygen species (ROS), including superoxide anion radical, hydrogen peroxide(•O2), hydroxyl radical (OH⋅), are formed continuously as a consequence of metabolic reactions. For example, mitochondria (oxidative phosphorylation), leukocytes (oxidative burst), peroxisomes (degradation of fatty acids) and cytochrome p450 system (mixed function oxidation system) can all release ROS. Under normal physiological conditions, there is a balance maintained between endogenous oxidants and antioxidants. When an imbalance occurs, created by the excessive generation of oxidants or a decrease of antioxidants, the abnormal oxidant system then enters what is called oxidative stress [1]. In the presence of oxidative stress, ROS generated in vivo can cause oxidative damage to lipids, proteins and nucleic acids. As a result, the DNA is constantly being damaged and oxidatively modified. It should be noted that DNA oxidative damage can also occur from exogenous ROS, such as cigarette smoking, UV radiation, and ionizing radiation [2].

Various markers of oxidative damage have been identified [1]. In the past, the most popular markers were designed for lipid peroxidation, such as malondialdehye (MDA), oxidized LDL, MDA-modified LDL, auto-antibodies against oxidized LDL and MDA-modified LDL, F2-isoprostane, and conjugated diene. The detection of a new carbonyl group, dityrosine and oxidized histidine has been measured to indicate protein oxidation. Markers for DNA oxidation were few. Only in recent years has 8-hydroxy-2′-deoxyguanosine (8-OHdG, or 8-oxodG) emerged as a marker of oxidative stress [3]. Urinary 8-OHdG, in particular, has been measured most frequently to indicate the extent of oxidative damage because it is noninvasive and technically less involved.

It is well known that the study of oxidative DNA damage is clinically important [1]. Numerous studies have shown that oxidative DNA damage links pathogenically to a variety of aging-associated degenerative diseases such as cancer, coronary heart disease and diabetes. Quantification of urinary 8-OHdG, a specific DNA repair products in the urine, can be made with a simple ELISA [4].

Section snippets

Oxidative DNA lesion

Nuclear and mitochondrial DNA from tissue and blood lymphocyte is usually the site of oxidation damage [5]. Among all purine and pyridine bases, guanine is most prone to oxidation. Upon oxidation a hydroxyl group is added to the 8th position of the guanine molecule and the oxidatively modified product 8-OHdG (Fig. 1) is one of the predominant forms of free radical-induced lesions of DNA. Oxidative modified DNA in the form of 8-OHdG can be quantified to indicate the extent of DNA damage. In

Nomenclature

Names used in the literature for oxidatively oxidized products have not been standardized and have created much confusions during reading. For example:

  • &#x02022;

    The abbreviation for the major oxidized nucleoside mentioned in this review, 8-hydroxy-2′-deoxyguanosine, is 8-OHdG. But 8-oxodG is also being used in the literature.

  • &#x02022;

    8-OHdG is the oxidized product of DNA, whereas 8-OHG is from RNA.

  • &#x02022;

    8-OHGua is the oxidized product of free guanine base, whereas 8-OHG represents 8-hydroxy-2′-guanosine, an oxidized

High-performance liquid chromatography (HPLC)

In the past, an HPLC procedure with electrochemical detection has been used most frequently for the determination of 8-OHdG. HPLC remains the method to quantify 8-OHdG in tissue, lymphocyte and plasma. To analyze 8-OHdG in tissue and lymphocyte, 8-OHdG has to be released from the nuclear DNA into soluble compound with enzymes before it can be quantified by HPLC. HPLC procedure has the advantage of measuring several oxidized products at the same time.

HPLC procedure has also been used to

Impact on carcinogenesis

The oxidative hydroxylation of guanine in the 8-position is the most frequent and most mutagenic lesion in nuclear DNA. Oxidative damage to DNA, reflected in the formation of 8-OHdG, is important in mutagenesis and carcinogenesis. The 8-hydroxylation of guanine (8-OHGua) leads to lack of base pairing specificity and misreading of the modified base and adjacent residues. During the repair of deficient bacterial and yeast cells, it was found that there is an increase of the frequency of

Impact on atherogenesis

It is known that ROS and reactive nitrogen species (such as peroxynitrite) are generated in both atherogenesis and advanced atherosclerosis, particularly by macrophages [31], [32]. Therefore, oxidative DNA damage not only linked to an increased risk of developing cancer but also several degenerative chronic diseases, including coronary artery disease (CAD).

It is well known that the formation of ROS promotes cell proliferation in atheroslerosis, hypertrophy, growth arrest, apoptosis and

Impact on diabetes

Increasing evidence in both experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of both types of diabetes mellitus (I and II). Oxidative stress appears to be the pathogenic factor in underlying diabetic complications. Free radicals are formed disproportionately in diabetes by glucose oxidation, nonenzymatic glycation of proteins, and the subsequent oxidative degradation of glycated proteins. Consequently, the free radicals thus generated

Normal reference range

We now realize that because ROS can be produced endogenously such as from mitochondria, oxidative damage also occurs in normal individuals. Therefore we have made an attempt establishing normal reference range for oxidatively modified DNA and RNA including urinary 8-OHdG with our in-house ELISA [4]. We found that the normal range of urinary oxidatively damaged products for females was 43.9±42.1 ng/mg creatinine (N=486), and 29.6±24.5 ng/mg creatinine for males (N=548). The age distribution of

Monitoring antioxidant supplementation

Urinary 8-OHdG has also been used to assess the effectiveness of dietary supplements with regard to whether they will reduce the oxidative damage. For example, the measurement of the urinary excretion rate of 8OHdG was used to demonstrate the protective effect of dietary supplementation with antioxidants on the prevention of carcinogenesis [50]. The level of 8-OHdG in sperm DNA has also been used to determine the effect of vitamin C intake [52]. Levels of 8-OHdG in mononuclear cell DNA, serum

References (54)

  • S. Toyokuni et al.

    Persistent oxidative stress in cancer

    FEBS Lett.

    (1995)
  • M. Foksinski et al.

    The level of typical biomarker of oxidative stress 8-hydroxy-2′-deoxyguanosine is higher in uterine myomas than in control tissues and correlates with the size of the tumor

    Free Radic. Biol. Med.

    (2000)
  • A. Matsui et al.

    Increased formation of oxidative DNA damage, 8-hydroxy-2′deoxyguanosine, in human breast cancer tissue and its relationship to GSTP1 ad COMT genotypes

    Cancer Lett.

    (2000)
  • M. Erhola et al.

    Biomarker evidence of DNA oxidation in lung cancer patients: association of urinary 8-hydroxy-2′-deoxyguanosine excretion with radiotherapy, chemotherapy, and response to treatment

    FEBS Lett.

    (1997)
  • T. Kitada et al.

    In situ detection of oxidative DNA damage, 8-hydroxydeoxyguanosine, in chronic human liver disease

    J. Hepatol.

    (2001)
  • J. Musarrat et al.

    Prognostic and aetiological relevance of 8-hydroxyguanosine in human breast carcinogenesis

    Eur. J. Cancer

    (1996)
  • Y. Dincer et al.

    Assessment of DNA base oxidation and glutathione level in patients with type 2 diabetes

    Mutat. Res.

    (2002)
  • H. Prieme et al.

    No effect of supplementation with vitamin E, ascorbic acid, or coenzyme Q10 on oxidative DNA damage estimated by 8-oxo-7,8-dihydro-2′-deoxyguanosine excretion in smokers

    Am. J. Clin. Nutr.

    (1997)
  • M.S. Cooke et al.

    Novel repair action of vitamin C upon in vivo oxidative DNA damage

    FEBS Lett.

    (1998)
  • B. Halliwell et al.

    Free radicals in biology and medicine

    (1999)
  • S. Loft et al.

    Oxidative DNA damage estimated by 8-hydroxydeoxyguanosine excretion in humans: influence of smoking, gender and body mass index

    Carcinogenesis

    (1992)
  • Chiou C-C, Chang P-Y, Chan E-C, Wu T-L, Tsao K-C, Wu TJ, Urinary 8-hydroxydeoxyguanosine and its analogues as DNA...
  • A. Weimann et al.

    Quantification of 8-oxo-guanine and guanine as the nucleobase, nucleoside and deoxynucleoside forms in human urine by high-performance liquid chromatography-electrospray tandem mass spectrometry

    Nucleic Acids Res.

    (2002)
  • M.S. Cooke et al.

    Urinary 8-oxo-2′-deoxyguanosine-source, significance and supplements

    Free Radic. Res.

    (2000)
  • S. Loft et al.

    Estimation of oxidative DNA damage in man from urinary excretion of repair products

    Acta Biochim. Pol.

    (1998)
  • H. Tsuboi et al.

    8-hydroxydeoxyguanosine in urine as an index of oxidative damage to DNA in the evaluation of atopic dermatitis

    Br. J. Dermatol.

    (1998)
  • K. Shimoi et al.

    Comparison between high-performance liquid chromatography and enzyme-linked immunosorbent assay for the determination of 8-hydroxy-2′-deoxyguanosine in human urine

    Cancer Epidemiol. Biomarkers Prev.

    (2002)
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