MedWire News: Children with celiac disease have higher than normal levels of the oxidative DNA damage biomarkers urinary 8-oxodG and 8-oxoGua, regardless of their diet, report researchers.
"Patients with celiac disease face increased risk of cancer and there is considerable circumstantial evidence that oxidatively damaged DNA may be used as a marker predictive of cancer development," explain Ryszard Olinski (Nicolaus Copernicus University, Bydgoszcz, Poland) and colleagues.
The researchers assessed levels of oxidative stress or oxidative DNA damage in 42 untreated and 75 treated (strict gluten-free diet) children with celiac disease with a mean age of 14.1 and 15.4 years, respectively. A group of 24 age-, gender-, and eating habit-matched controls were also included for comparison purposes.
The researchers measured urinary excretion of the biomarkers 8-oxodG and 8-oxoGua, as well as the level of oxidatively damaged DNA present in the leukocytes (8-oxodG).
Levels of leukocyte and urinary 8-oxodG and urinary 8-oxoGua were significantly higher in both treated and untreated celiac patients compared with controls.
In untreated and treated celiacs, and control children, mean levels of 8-oxodG in the urine were 2.48, 2.16, and 1.59 nmol/mmol of creatinine, respectively. Levels of urinary 8-oxoGua in the corresponding groups were 14.38, 11.66, and 7.78 nmol/mmol of creatinine.
Leukocyte levels of 8-oxodG in the same groups were 6.80, 6.16, and 4.39 per 106 unmodified dG.
Interestingly, treatment with a gluten-free diet did not seem to significantly reduce the concentration of 8-oxodG or 8-oxoGua, which suggests that "although diet can be partially responsible for oxidative stress/oxidatively damaged DNA in celiac patients, there is a factor independent of diet," write the authors.
"We recently showed that oxidatively damaged DNA is inversely correlated with the endogenous level of antioxidant vitamins and that vitamin A has the strongest effect of all antioxidant components on the damage," say Olinski et al.
They found that the untreated celiac children in the study had significantly lower levels of vitamin A and E (between group difference of 0.31 and 3.76 µmol/l, respectively) than the treated celiac children, suggesting that consumption of a gluten-free diet does at least partially ameliorate oxidative damage in these individuals.
The results of this study are published in the journal Cancer Epidemiology, Biomarkers and Prevention.
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