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The presence of some species of helminths is associated with changes in host microbiota composition and diversity, which varies widely depending on the infecting helminth species and other factors. We conducted a prospective case-control study to evaluate the gut microbiota in children with Opisthorchis felineus infection (n=50) before and after anthelmintic treatment and in uninfected children (n=49) in the endemic region. A total of 99 children and adolescents aged between 7 and 18 years were enrolled to the study. Helminth infection was assessed before and at 3 months after treatment with praziquantel. A complex examination for each participant was performed in the study, including an assessment of the clinical symptoms and an intestinal microbiota survey by 16S rRNA gene sequencing of stool samples. There was no change in alpha diversity between O. felineus-infected and control groups. We found significant changes in the abundances of bacterial taxa at different taxonomic levels between the infected and uninfected individuals. Enterobacteriaceae family was more abundant in infected participants compared to uninfected children. On the genus level, O. felineus-infected participants' microbiota showed higher levels of Lachnospira, Escherichia-Shigella, Bacteroides, Eubacterium eligens group, Ruminiclostridium 6, Barnesiella, Oscillibacter, Faecalitalea and Anaerosporobacter and reduction of Blautia, Lachnospiraceae FCS020 and Eubacterium hallii group in comparison with the uninfected individuals. Following praziquantel therapy, there were significant differences in abundances of some microorganisms, including an increase of Faecalibacterium and decrease of Megasphaera, Roseburia. Enterobacteriaceae and Escherichia abundances were decreased up to the control group values. Our results highlight the importance of the host-parasite-microbiota interactions for the community health in the endemic regions., (Copyright © 2021. Published by Elsevier B.V.)

Although data on oxidative stress during liver fluke infection have been previously presented, a comprehensive study of the glutathione system that plays a crucial role in scavenging of reactive oxygen species (ROS) and detoxification of primary and secondary oxidation products has not been addressed yet. In the present study, the hepatic glutathione system was investigated in a hamster model of experimental opisthorchiasis infection. It was shown that chronic oxidative stress in an Opisthorchis felineus infected liver, evidenced by abundant hydroperoxide accumulation, leads to strong imbalance in the hepatic glutathione system, namely the depletion of reduced form of glutathione (GSH), lowering of the GSH/GSSG ratio, and a decrease in the glutathione peroxidase and glyoxalase 1 activity. O. felineus infection provokes hepatocellular damage that results in the progression of liver fibrosis, accompanied by an increase in collagen deposition in the hepatic tissue. Modulation of hepatic GSH levels in the O. felineus infected liver through N-acetylcysteine (NAC) or l-buthionine-S, R-sulfoxinine (BSO) treatments lead to changes in expression and activity of glutathione S-transferase and glyoxalase I as well as markedly decreases or increases collagen content in the O. felineus infected liver and the severity of liver fibrosis, respectively. Thus, the glutathione system can be considered as a target for liver protection from O. felineus-induced injury., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Infection with the fish borne liver fluke Opisthorchis felineus is common in the Eastern Europe (Ukraine, European part of Russia), Northern Asia (Siberia) and Central Asia (Northern Kazakhstan). Better understanding of the molecular pathogenesis of the biliary tract and liver during chronic opisthorchiasis can be expected to improve protection against and management of complications of this disease. We hypothesize that infection with O. felineus associates with formation of methylglyoxal and carbonyl stress in the liver and hence here we investigated the glyoxalase system and the receptor for advanced glycated end products (RAGE) in the liver of hamsters infected with this liver fluke. Expression of mRNA encoding glyoxalase 1 decreased at 8weeks of the infection and catalytic activity as well decreased at 8 and 12weeks after infection, and the expression of the glyoxalase 2 decreased until 36week post-infection, which associated with the decreasing activity of the enzyme at 8 and 12weeks post-infection. Glutathione levels in infected livers had decreased at week 8, whereas up-regulation of RAGE at mRNA levels was seen for the extended duration of the experimental infection of the hamsters. This outcome supported the notion of hepatic dicarbonyl stress during chronic opisthorchiasis. The inhibition of the glyoxalase system and accumulation of methylglyoxal at the early stages of the infection may underpin development of insulin resistance during opisthorchiasis., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Opisthorchis felineus (O. felineus) occurs in Western Siberia and many other parts of the Russian Federation (RF). The true extent of its distribution is not known. Chronic infection may lead to severe hepatobiliary morbidity. According to surgical and experimental reports, long-term infestation might significantly increase the risk for cholangiocarcinoma (CCA). To date, no association between O. felineus infection and CCA has been demonstrated. The objective of this study was to review existing health data on the incidence of O. felineus infection and on the incidence of CCA in the RF. We reviewed the official medical statistics on reported O. felineus infection and CCA in 83 political/geographical units of the RF, covering the period January 2011-December 2013. Annual incidence data were obtained from Rospotrebnadzor and from official medical statistics. We calculated the average annual incidence of infection and cancer. The average annual incidence of O. felineus was 24.7±9.0 cases per 100,000 population. The highest incidence was observed in Khanty-Mansiysk district (599.7 cases per 100,000 population per year). In 27 geographical units, no O. felineus cases were reported. The incidence of liver and intrahepatic bile duct cancers was 4.8±0.2 cases per 100,000 population; the highest rate was reported in Sakha Republic and Tomsk Oblast (14.5 and 9.3 cases per 100,000 population), and the lowest in Yamalo-Nenets Autonomous Okrug (0.9 cases per 100,000 population). O. felineus incidence was not associated with the mean annual incidence of liver and intrahepatic bile duct cancers (r=0.20, p=0.07). This study documents the importance of opisthorchiasis in certain endemic areas and presents the best available data on associations between O. felineus infection and liver/intrahepatic bile duct cancers in RF. The findings support the need to implement a public health control programme against liver fluke infections and to increase the availability of anthelmintic treatment. Further studies are warranted to assess the contribution of opisthorchiasis to the CCA in RF., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

According to epidemiological observations, Opisthorchis felineus liver fluke invasion is negatively associated with the development and severity of allergic diseases in endemic regions of Russia. We hypothesized that the invasion is an important factor in gene-environmental interactions (GEI) underlying allergy. To prove this, we tested 10 single nucleotide polymorphisms of immune response modifying genes in 428 individuals stratified by atopic bronchial asthma presence and O. felineus invasion. Using regression models, a statistically significant interaction between the rs6737848 polymorphism of SOCS5 gene and O. felineus invasion was observed (pint=0.001, OR=5.66, 95% CI 1.96-16.31 for dominant model; pint=0.003; OR=4.38, 95% CI 1.68-11.45 for additive model). The interaction is based on the statistically significant association between the SOCS5 gene and atopic bronchial asthma in patients without O. felineus infection, while no such association is seen in patients infected by the helminth. These data confirm for the first time the importance of the helminth invasion as an environmental factor influencing the association between genetic factors and atopic bronchial asthma. In particular, O. felineus diminishes the risk of atopic bronchial asthma associated with the SOCS5 gene polymorphism., (Copyright © 2014 Elsevier B.V. All rights reserved.)