The authors declare no financial or commercial conflicts of interest. “
“Opisthorchis viverrini infection causes opisthorchiasis and is a risk factor

for cholangiocarcinoma via chronic inflammation. To investigate the mechanism of O. viverrini -induced liver disease, we applied a proteomic approach to examine alterations in hepatic protein levels in O. viverrini -infected hamsters. Two-dimensional gel electrophoresis (2DE) revealed that O. viverrini infection induced upregulation (1·5- to 4·3-fold) of 25 proteins and downregulation (1·5 to 2·5-fold) of 24 proteins compared with uninfected animals. Expression of proteins related to stress response, DNA replication and repair, and cell structure was significantly increased, whereas that of proteins ABT-263 associated with normal liver function, such as metabolism, blood volume maintenance and find more fatty acid cycle was decreased. Among the upregulated proteins, a 2·7-fold increase in peroxiredoxin 6

(Prdx6), an antioxidant protein, was confirmed by 2DE and immunoblot analysis, Western blot and quantitative PCR. Immunohistochemical analysis showed that Prdx6 expression was observed mainly in the cytoplasm of inflammatory cells. These results suggest that Prdx6 is important for host defence against O. viverrini infection. This study provides basic information for Prdx6 as a potential biomarker and therapeutic target for opisthorchiasis. Infection with human liver fluke, Opisthorchis viverrini, causes opisthorchiasis, a major public health problem affecting the poorest regions of South-East Asia, including Thailand, Lao People’s Democratic Republic, Cambodia and central Vietnam (1). In Thailand, eight million people are estimated to be infected with O. viverrini, representing about 9·6% of the population (2). Humans become infected with O. viverrini by consuming raw or undercooked fish, which contains the infective metacercaria stage of the parasite. The parasite migrates to intrahepatic bile Protein kinase N1 ducts via the common bile duct, and produces eggs that are excreted in the faeces after approximately 30 days (3). The disease is usually persistent

for many years with chronic infection and remains clinically silent unless detected by ultrasonography (4). Chronic O. viverrini infection induces various hepatobiliary diseases, including cholangitis, cholecystitis, gallstones, hepatomegaly and intrahepatic cholangiocarcinoma (CCA) (1). The highest incidence of CCA occurs in the north-eastern region of Thailand, especially Khon Kaen Province, where O. viverrini infection is endemic (5,6). A cellular response to parasite antigens released from mature worm stimulates a local inflammatory response (7). Host immune responses to mechanical and immunological irritation caused by parasites lead to release of free radicals, growth factors, proteolytic enzymes and fibrogenic cytokines from inflammatory and epithelial cells, which contribute to a variety of pathologies including CCA (6,8,9).