Opisthorchiasis-Induced Cholangiocarcinoma: How Innate Immunity May Cause Cancer

Unraveling the relationship among inflammatory responses, oxidative damage, and host susceptibility to Opisthorchis viverrini infection: A comparative analysis in animal models

Background and Aim

Opisthorchis viverrini infection-induced inflammation contributes to cholangiocarcinoma (CCA) development in humans and animals. Inflammation generates free radicals, such as reactive oxygen species and reactive nitrogen species (RNS), which damage the host's DNA. However, only 5% of O. viverrini-infected individuals develop malignancy, suggesting that variations in the inflammatory response of individuals to the parasite may influence susceptibility. Due to limitations in studying human susceptibility, we used an animal model to investigate the profiles of inflammatory reactions, oxidative burst, and irreversible DNA damage. This study aimed to explore the potential role of inflammation and RNS in causing DNA damage that may predispose susceptible hosts and non-susceptible animal models to cancer development in O. viverrini infection.

Materials and Methods

This experimental study was conducted on 30 Syrian golden hamsters (OV-H) and 30 BALB/c mice (OV-M) infected with O. viverrini, representing susceptible and non-susceptible models, respectively. Five animals per group were examined at six predetermined time points during the experiment. Biliary tract samples were systematically investigated using histopathological evaluation for inflammatory cell infiltration and immunohistochemical staining for RNS production and markers of DNA damage, including nitrotyrosine and 8-hydroxy-2'-deoxyguanosine. These features were quantified and compared among the experimental groups. Mann-Whitney U-test was used for statistical analysis, with p < 0.05 considered statistically significant.

Results

The comparison revealed that the OV-M group exhibited significantly earlier and higher rates of inflammatory cell infiltration during the acute phase, whereas the OV-H group exhibited chronic and more severe inflammation (p < 0.020). Intracellular RNS production and DNA damage were closely associated with the inflammatory response.

Conclusion

This study demonstrates differential responses in susceptible and non-susceptible models of O. viverrini infection regarding disease onset and duration, as well as intracellular RNS production and DNA damage caused by inflammation. Persistent inflammation generated oxidatively damaged DNA, which is a distinct pathological characteristic of susceptible hosts and may be critical for CCA development.

Neutrophil function following treatment of psoriatic arthritis patients with secukinumab: altered cytokine signalling but no impairment of host defence

OBJECTIVES

Identifying that dysfunction of the IL-23/17 axis underlies PsA has led to the development of effective targeted therapies such as the IL-17A inhibitor secukinumab. As IL-17A stimulates the secretion of neutrophil chemoattractants, such as CXCL8 (IL-8), we examined the effect of secukinumab on neutrophil function in PsA.

METHODS

Nineteen patients with active PsA were treated with secukinumab. Clinical response [PsA Response Criteria (PsARC) and Psoriasis Area and Severity Index (PASI)] and peripheral blood neutrophil function (apoptosis, receptor expression, phagocytosis/killing, chemotaxis and RNA expression) were measured at 12 week intervals for 48 weeks and compared with age- and sex-matched healthy controls.

RESULTS

At 12 weeks, 12/16 (75%) patients had a PsARC response (100% at 36 weeks) and 10/14 (71%) achieved a 90% PASI response. At baseline, there were no differences in PsA neutrophil reactive oxygen species generation, constitutive or cytokine-delayed apoptosis, chemotaxis or phagocytosis of opsonized Staphylococcus aureus compared with healthy controls. Similarly, there were no differences in these functions from baseline to 12 weeks of therapy. However, surface levels of CD11b/CD18 and CD63 increased and expression of CD16 decreased during therapy. In addition, in a subgroup of early (12 week) responders to secukinumab, RNA sequencing revealed transcriptome changes predicting down-regulation of cytokine signalling and chemotaxis pathways and up-regulation of de novo gene expression pathways, including translation initiation, mRNA catabolism and translation.

CONCLUSION

Complex changes in the properties of circulating neutrophils occur with secukinumab treatment in PsA that may indicate altered responsiveness to changes in both local and systemic levels of pro-inflammatory cytokines. However, host defence processes of neutrophils were unaltered.

Neutrophils form extracellular traps in response to Opisthorchis viverrini crude antigens, which are elevated in neutrophils from opisthorchiasis patients with hepatobiliary abnormalities

Opisthorchis viverrini (Ov) infection can cause several disease conditions of the bile duct including hepatobiliary abnormalities (HBAs) and the most severe, cholangiocarcinoma (CCA). Fibrosis occurs when tissues are damaged and normal wound-healing responses are dysregulated. Neutrophils are the first cells to migrate to an infection site to protect the host from intruding extracellular pathogens through a wide range of effector mechanisms such as phagocytosis, production of reactive oxygen species, proteases, or release of neutrophil extracellular traps (NETs). In this work, we used confocal microscopy to assess whether Ov crude antigens can cause release of NETs from neutrophils from Ov-free individuals. We demonstrated for the first time that these antigens could induce release of NETs ex vivo in a dose-dependent manner from neutrophils isolated from Ov-free individuals. Intriguingly, when we measured NETs from neutrophils isolated from Ov-infected patients, we found increased spontaneous production of NETs in patients with HBAs. Interestingly, exposure to Ov crude antigens lowered the level of NETs released by neutrophils from patients with active Ov infection regardless of HBA status. We propose that in the case of acute Ov infection, even when concentration of Ov antigens is relatively low, neutrophils can form NETs. However, when this infection becomes chronic, manifesting as a definite HBA, the levels of NET production are reduced when treated with Ov crude antigens. Excessive production of proinflammatory mediators from these NETs might have effects on the parasites, but may also lead to excessive injury of surrounding tissues resulting in HBAs and may lead eventually to the most severe complications such as CCA.

A systematic review and meta-analysis on the co-infection of Helicobacter pylori with intestinal parasites: public health issue or neglected correlation?

The current study was conducted to assess the prevalence and odds ratio (OR) of co-infection of Helicobacter pylori (H. pylori) and intestinal parasites (IPs). English databases were searched. A total of 18 studies including 14 studies with cross-sectional design (a total of 3739 participants) and 4 studies with case-control design (397 patients and 320 controls) met the eligibility criteria. The pooled prevalence of H. pylori, intestinal parasite infections (IPIs), and their co-infections in different populations were 48.3% (95% CI, 34.1-62.8%), 15.4% (95% CI, 10-22.8%), and 11% (95% CI, 6.7-17.6%), respectively. The co-infection of H. pylori and Giardia was 7.6% (95% CI, 4.9-11.7%). Although statistically not significant, the risk of co-infection of H. pylori and IPIs was higher in case group compared to control group (OR, 1.59; 95% CI, 0.77-3.25). The overlaps between H. pylori and IPIs in countries with lower human development index (HDI) and income levels were high.

Epithelial-Mesenchymal Transition in Liver Fluke-Induced Cholangiocarcinoma

Simple Summary

Parasitic infection remains a health threat in many countries. Liver flukes, parasitic flatworms endemic to southeast and east Asia, cause bile duct inflammation and are major risk factors of bile duct cancer (cholangiocarcinoma). As the only group of eukaryotic organisms listed as carcinogens, liver flukes can increase cholangiocarcinoma incidence by 100-fold in some parts of Thailand. How they interact with bile duct epithelial cells during tumor initiation and progression is unknown. In this review, we summarize molecular and cellular evidence linking liver fluke-associated cholangiocarcinoma with mis-regulation of epithelial–mesenchymal transition (EMT), a multicellular morphogenetic process known to be involved in many normal and pathological settings, including cancer. EMT markers and regulators can potentially be used to facilitate cholangiocarcinoma diagnosis and treatment.

Abstract

Cholangiocarcinoma (CCA) is the second most common type of hepatic cancer. In east and southeast Asia, intrahepatic CCA is caused predominantly by infection of Opisthorchis viverrini and Clonorchis sinensis, two species of parasitic liver flukes. In this review, we present molecular evidence that liver fluke-associated CCAs have enhanced features of epithelial–mesenchymal transition (EMT) in bile duct epithelial cells (cholangiocytes) and that some of those features are associated with mis-regulation at the epigenetic level. We hypothesize that both direct and indirect mechanisms underlie parasitic infection-induced EMT in CCA.

Animation as Supplementary Learning Material About Carcinogenic Liver Fluke in Classes for Primary Schoolchildren

Carcinogenic liver fluke is still an issue of great concern in some countries of Southeast Asia, particularly in Thailand, Cambodia, the Lao People's Democratic Republic, and Vietnam. The infection, caused by Opisthorchis viverrini, is associated to cholangiocarcinoma and is endemic among human populations for whom raw fish is frequently consumed. Prevention and health education are required. Therefore, this study aimed to evaluate the effectiveness of educational intervention to improve knowledge among primary schoolchildren based on animation-assisted education. In this study, 80 participants (40 participants in the experimental group and 40 participants in the comparison group) were selected in 2018. The effectiveness of an interactive animation program in improving the knowledge of students studying liver fluke was determined based on scores on tests given before and immediately after completion of a 4.29-min animated program on the liver fluke life cycle, risk factors, disease, diagnosis, treatment, prevention, and control. Data were analyzed using SPSS-22 via paired t tests and independent samples t tests at a significance level of 0.05. A marked and significant improvement was observed in the immediate posttest compared with the pretest scores. More importantly, the students who had used the animated program achieved a significantly higher score on the final test than the comparison group. The results offered in the first report show that the use of the animated program facilitated education about liver fluke. It is strongly believed that animations are good supplementary learning materials for students, particularly for learning about serious concepts.

Enhanced neutrophil functions during Opisthorchis viverrini infections and correlation with advanced periductal fibrosis

Millions of people are infected with the liver fluke, Opisthorchis viverrini (OV), but only ~25% of those infected develop liver disease and even fewer develop cholangiocarcinoma. The reasons for these differential outcomes following infection are unknown but it has been proposed that differential immune responses to the parasite may play a role. We therefore measured granulocyte (neutrophil) function in OV-infected individuals, with and without advanced periductal fibrosis, to determine if these cells have a "pro-inflammatory" phenotype that may contribute to liver disease post-infection. A case-controlled study (n = 54 in each cohort) from endemic OV-infected areas of northeastern Thailand measured neutrophil functions in whole blood from non-infected (healthy controls) and OV-infected individuals with and without APF. We measured reactive oxygen species production, phagocytosis, receptor expression and apoptosis. Secreted products from OV cultures (obtained after in vitro culture of parasites) stimulated reactive oxygen species production in non-infected healthy controls, but levels were two-fold greater after OV infection (P < 0.0001); neutrophil reactive oxygen species production in individuals with APF was double that observed in those without APF (P < 0.0001). OV-infected neutrophils had elevated CD11b expression and greater phagocytic capacity, which was even three-fold higher in those with advanced periductal fibrosis (P < 0.0001). This "activated" phenotype of circulating neutrophils was further confirmed by the observation that isolated neutrophils had delayed apoptosis ex vivo. We believe this is the first study to show that circulating blood neutrophil function is enhanced following OV infection and is more activated in those with advanced periductal fibrosis. We propose that this activated phenotype could contribute to the pathology of liver disease. These data support the hypothesis of an activated innate inflammatory phenotype following OV infection and provide the first evidence for involvement of neutrophils in disease pathology.

Effect of Educational Intervention Based on the Health Belief Model and Self-Efficacy in Promoting Preventive Behaviors in a Cholangiocarcinoma Screening Group

Cholangiocarcinoma (CCA) is a neoplasm known as one of the most common causes of cancer-related deaths in Southeast Asia, particularly in Thailand, Laos, and Cambodia. Prevention and health education are required. Therefore, this study aimed to determine the effectiveness of an educational intervention to prevent CCA among a rural population in Thailand based on the health belief model (HBM) and self-efficacy frameworks. In this quasi-experimental study, 60 participants (30 participants in the experimental group and 30 participants in the control group) were selected in 2017. The educational intervention for the experimental group consisted of seven training sessions (introduction to CCA, risk factors, complications, benefits and barriers to proper consumption of cooked fish, carcinogenic agents, behavioral protection, and self-efficacy in applying preventive behaviors). A questionnaire that consisted of demographic information, knowledge, and HBM constructs (perceived susceptibility, severity, benefits, barriers, cues to action, and self-efficacy) was used to measure CCA preventive behaviors before and 3 months after the intervention. Data were analyzed using SPSS-22 via chi-squared, paired t-tests, and independent samples t tests at a significance level of 0.5. Three months after the intervention, the experimental group showed a significant increase in the knowledge, perceived susceptibility, perceived severity, perceived benefits, perceived barriers, cues to action, self-efficacy, and CCA preventive behaviors compared to the control group. This study showed the effectiveness of the intervention based on the HBM constructs and self-efficacy in the adoption of CCA preventive behaviors 3 months post intervention in the risk group. Thus, these models may serve as a framework for designing and implementing educational interventions for the prevention of CCA.

Is Opisthorchis viverrini Emerging in Cambodia?

Opisthorchis viverrini infection is widely prevalent in Southeast Asia. In Cambodia information on this helminth infection is scare. Recent reports suggest that O. viverrini is an emerging public health problem. We aimed to synthesize all information in relation to the infection, epidemiology, and morbidity of O. viverrini in Cambodia; from published as well as thus far unpublished sources. First reports on O. viverrini date back to 1995. In 2006 an O. viverrini initiative was launched by the national helminth control program. Since then O. viverrini has been reported in all - except two - provinces. Villages with high prevalences (>20%) were found in provinces from Preah Vihear to Takeo. The infection has a highly focal distribution. In many villages no infections were detected. O. viverrini infection was also reported in cats, dogs and intermediate hosts. No report on morbidity associated with O. viverrini was found. The current evidence suggests that O. viverrini infection remains underreported in Cambodia. It is likely that the transmission will further increase in the future with potentially serious consequences for human health.

The Effect of Health Behavior Modification Program for Liver Fluke Prevention among the Risk Group in Rural Communities, Thailand

This quasi-experimental research aimed to study the effect of health behavior modification program in relation to knowledge, self-efficacy, expectation, and practice for liver fluke prevention among the risk group from Bueng Samrong sub-district, Kaeng Sanam Nang district, Nakhon Ratchasima province, Northeast Thailand. The total of 66 participants was assigned to experimental and comparison group, 33 participants in each group, 12-weeks intervene period. The experimental group was received health behavioral modification programs based on health education, self-efficacy, motivation, social support and networking. Pre-and-post-tests were measured using predesigned questionnaires. The comparative analysis was analyzed by paired sample t-test and independent sample t-test at the 0.05 level of significance. The results revealed that the experimental group had significantly greater knowledge, self-efficacy, expectation, and practice for liver fluke prevention than those in the comparison group (p < 0.05). In conclusion, this was a successful health education program for liver fluke avoidance. Participants were gained the correct knowledge and had the higher self-efficacy, expectation, and practice regrading liver fluke prevention. Therefore, it may useful for further behavior modification in the other epidemic areas.

Update on Pathogenesis of Opisthorchiasis and Cholangiocarcinoma

Infection with the food-borne liver fluke Opisthorchis viverrini causes cholangiocarcinoma (CCA). Whereas the cause of CCA in the West remains obscure, the principal risk factor in Thailand is opisthorchiasis. Here, we review recent findings on the pathogenesis of opisthorchiasis and CCA focusing on helminth molecules/toxic metabolites, host-parasite interaction, endocytosis, immunopathology/inflammatory responses, free radical production, molecular genetic alterations, and multifactorial including coinfections driving to CCA development.