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

Abstract

Oxidative DNA damage may be implicated in ageing, carcinogenesis and other degenerative diseases. Oxidative DNA damage can be assessed in humans in vivo from the urinary excretion of the DNA-repair product 8-hydroxydeoxyguanosine (8OHdG). We investigated factors influencing the excretion of 8OHdG in 24 h urine from 83 randomly selected healthy subjects (52 women) aged 40-64 years. For 2 weeks prior to urine collection the subjects kept a weighed diet record. 8OHdG was quantified by an automatic three-dimensional HPLC analysis with electrochemical detection. The 8OHdG excretion was 252 +/- 103 (mean +/- SD) pmol kg body weight/24 h with a range from 78 to 527. Multiple regression analysis identified three factors, smoking, body mass index (BMI) and gender, as significant predictors of the 8OHdG excretion. In 30 smokers the 8OHdG excretion was 320 +/- 99 pmol/kg/24 h opposed to 213 +/- 84 pmol/kg/24 h in 53 non-smokers. According to multiple regression analysis smokers excreted 50% (31-69%; 95% confidence interval) more 8OHdG than non-smokers. In 52 women the 8OHdG excretion was 240 +/- 106 pmol/kg/24 h opposed to 271 +/- 96 pmol/kg/24 h in 31 men. According to the multiple regression analysis men excreted 29% (10-48%) more 8OHdG than women. According to multiple regression analysis the 8OHdG excretion decreased with 4% (2-6%) per increment in BMI measured in kg/m2. The dietary distribution of energy demonstrated no important predictive value with respect to 8OHdG excretion. The intake of the antioxidant vitamins C and E and of vitamin A equivalents, including beta-carotene, was not associated with 8OHdG excretion. The results suggest that smoking increases oxidative DNA damage by approximately 50%. This effect implies potential serious health effects adding to the other well-known health hazards of smoking. The higher 8OHdG excretion in men and lean subjects may be related to a higher rate of metabolism with increased availability of reactive oxygen species. The apparent 7-fold individual variation in oxidative DNA damage carries implications regarding the rate of ageing and the risk of cancer and other degenerative diseases. The excretion of 8OHdG into urine offers a valuable tool for testing such hypotheses in humans.

Determination of urinary oxidative DNA damage marker 8-hydroxy-2′-deoxyguanosine and the association with cigarette smoking

“…Previous reports investigated the effect of pH on migration time and theoretical plate and indicated that borate used as running buffer could be successfully used to separate 8OHdG in DNA sample [9]. A recent report [31] found that though zwitterionic buffers exhibit lower electrophoretic currents than borate or phosphate buffers, no resolution of 8OHdG from matrix interferences was observed with the three selected zwitterionic buffers.…”

“…Among more than 20 DNA oxidized adducts, 8-hydroxy-2 -deoxyguanosine (8OHdG) is a major products formed by hydroxyl radical attack on the guanine residues of DNA [7,8]. When damaged DNA is repaired, 8OHdG produced is excreted in urine without further metabolism [7,9]. It's reported that within 8OHdG viral genomes introduce G:C → T:A transitions in vivo [10,11].…”

“…Due to its mutagenic potential, 8OHdG has been widely suggested as a biomarker for various cancers [12][13][14]. The concentration of 8OHdG is also evaluated in smokers and non-smokers [9,15,16] since cigarette smoke contains a large amount of oxygen radical forming substances, such as catechol and hydroquinone that may enhance lung carcinogenesis by free radical-mediated reactions. Loft et al [9] reported smokers excreted 50% more 8OHdG than non-smokers in 24 h urine, indicating a 50% increased rate of oxidative DNA damage from smoking.…”

“…The concentration of 8OHdG is also evaluated in smokers and non-smokers [9,15,16] since cigarette smoke contains a large amount of oxygen radical forming substances, such as catechol and hydroquinone that may enhance lung carcinogenesis by free radical-mediated reactions. Loft et al [9] reported smokers excreted 50% more 8OHdG than non-smokers in 24 h urine, indicating a 50% increased rate of oxidative DNA damage from smoking. Asami et al [16] found a positive correlation between the number of cigarette smoked per day and the 8OHdG levels in normal lung tissues.…”

Study of urinary 8-hydroxydeoxyguanosine as a biomarker of oxidative DNA damage in diabetic nephropathy patients

“…When damaged DNA is repaired, 8-OHdG produced is excreted in urine without further metabolism [9,10]. Urinary 8-OHdG has been widely used as a sensitive marker of oxidative DNA damage and of the total systemic oxidative stress in vivo [11,12].…”