Parasite infection of Opisthorchis viverrini is a major risk factor for
cholangiocarcinoma. Our previous immunohistochemical studies showed that O. viverrini
infection induced oxidative DNA lesions in the bile duct epithelium during
cholangiocarcinoma development. The current study assessed the levels of
8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), an oxidative DNA lesion, in the urine and leukocytes of O. viverrini-infected subjects and
cholangiocarcinoma patients. Forty-nine O. viverrini-infected patients, 55
cholangiocarcinoma patients, and 17 healthy controls were enrolled in the study. We measured
8-oxodG levels in the urine and leukocytes of these subjects using an electrochemical detector coupled to high-performance liquid chromatography. O. viverrini-infected patients were assessed before treatment and 2 months and 1 year after
praziquantel treatment. Urinary
8-oxodG levels were significantly higher in
cholangiocarcinoma patients (6.83 +/- 1.00 microg/g
creatinine) than in O. viverrini-infected patients (4.45 +/- 0.25 mug/g
creatinine; P < 0.05) and healthy subjects (3.03 +/- 0.24 microg/g
creatinine; P < 0.01) and higher in O. viverrini-infected subjects than in healthy subjects (P < 0.01). The urinary
8-oxodG levels in O. viverrini-infected patients significantly decreased 2 months after
praziquantel treatment and were comparable with levels in healthy subjects 1 year
after treatment. Urinary
8-oxodG levels were significantly correlated with leukocyte
8-oxodG levels, plasma
nitrate/
nitrite levels, and
aspartate aminotransferase activity. In conclusion, this study, in addition to our previous studies, indicates that
8-oxodG formation by
parasite infection may play an important role in
cholangiocarcinoma development. Urinary
8-oxodG may be a useful
biomarker to monitor not only
infection but also
carcinogenesis.