RESUMO
Gender-related differences in the association between polymorphism of xenobiotic-metabolising enzymes or non-genetic biomarkers and susceptibility to oxidative stress was assessed in healthy middle-aged Serbian adults, by urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG/creatinine) and total antioxidant status in serum (TAOS). Females were more susceptible to oxidative stress. In both genders, positive predictor of the antioxidative protection was serum triglyceride, while BMI <25 kg/m(2) was associated with oxidative stress. Susceptibility to oxidative stress in males was associated with GSTT1*null allele and increased serum iron, but in females, it was decreased serum bilirubin. Early identification of the risk factors could be important in the prevention of oxidative stress-related diseases.
Assuntos
Biomarcadores/análise , Predisposição Genética para Doença/genética , Estresse Oxidativo , Polimorfismo Genético , 8-Hidroxi-2'-Desoxiguanosina , Adulto , Alelos , Antioxidantes/análise , Biomarcadores/sangue , Biomarcadores/urina , Creatinina/urina , Citocromo P-450 CYP1A1/genética , Desoxiguanosina/análogos & derivados , Desoxiguanosina/urina , Epóxido Hidrolases/genética , Feminino , Frequência do Gene , Genótipo , Glutationa S-Transferase pi/genética , Glutationa Transferase/genética , Humanos , Ferro/sangue , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Sérvia , Fatores SexuaisRESUMO
OBJECTIVES: Although there are many nucleobase modifications, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) is one of the dominant form of oxidative modifications of DNA. Urinary 8-oxodG is potentially the best non-invasive biomarker of oxidative stress. Defining reference interval for urinary 8-oxodG is a prerequisite for its clinical use as biomarker. DESIGN AND METHODS: Reference population included 229 healthy Serbian adults (130 males and 99 females). The spot urinary 8-oxodG was determined using high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS). Urinary creatinine was measured by the kinetic Jaffé method. RESULTS: Analytical performances of the HPLC-MS/MS: CVs within and between-run variations were 5.6% and 2.6%; LOD and LOQ were 1.65 nmol/L and 3.30 nmol/L; mean recovery and relative accuracy were 96% and 97%. Creatinine level was higher in males than in females, but no gender difference in 8-oxodG level was observed. Upon the adjustment of 8-oxodG to creatinine (8-oxodG/creatinine), higher values were obtained in females (1.38 ± 0.65 nmol/mmol) than in males (1.05 ± 0.48 nmol/mmol). Distribution of 8-oxodG/creatinine in spot urine sample was log-normal and gender-related reference intervals (estimated as the 2.5th-97.5th percentiles) were 0.45-2.22 nmol/mmol for males, and 0.54-3.11 nmol/mmol for females. Body mass index (BMI) affects excretion of the 8-oxodG in males, independently of urinary creatinine, while in females it does not. Therefore, BMI might contribute to the gender-related differences of 8-oxodG/creatinine in spot urine samples. CONCLUSIONS: This is the first established gender-related reference intervals of spot urinary 8-oxodG/creatinine. Our results contribute to the full validation of 8-oxodG as biomarker of oxidative stress.
