Modeling alcoholic hepatitis in mice: modified acute-on-chronic binge ethanol feeding and alcohol liquid diet models

Ethanol contributes to a wide spectrum of alcohol-induced liver injury in humans. The use of animal models enables understanding of the driving forces of liver damage. However, features and patterns of some liver pathology, such as alcoholic hepatitis, cannot be completely reproduced by existing animal models. Two experimental designs were implemented in order to reproduce an acute-on-chronic pattern of liver injury. In the first experiment, six-week old male C57/BL6J mice were randomly assigned to the injections of CCl4 (0.2ml/kg) or olive oil as vehicle for 6 weeks. Three days after cessation of CCl4 administration, mice received daily gavages of ethanol (4-5g/kg) or saline vehicle for 8 days (binge ethanol feeding model). In the second study after pre-injections with CCl4 mice were fed ad libitum with alcohol-containing modified Lieber-DeCarli liquid diet for 6 weeks (modified alcohol liquid diet model). Serum alcohol concentration and biomarkers of liver injury, histopathological evaluation of liver tissue sections, and the expression of genes, markers of myofibroblast formation, were assessed. The results of the study demonstrate that administration of low doses of CCl4 with following consumption of alcohol liquid diet caused the development of liver lesions similar to those in human alcoholic hepatitis.Master of Science in Public Healt

Metody detekce a kvantifikace parazitů rodu Leishmania jako nástroj pro studium vzájemného působení patogenu, vektoru a hostitele

Methods for Leishmania parasite detection and quantification as a tool for study of the pathogen-vector-host interactions Leishmaniasis in human is caused by total 21 species of the intracellular protozoan parasite Leishmania, which are transmitted by about 30 species of phlebotomine sand flies. Besides human, Leishmania can infect a number of vertebrate hosts. The major host cell is the macrophage, in which parasites multiply, eventually rupturing the cell and spreading to uninfected cells. Infected monocytes and macrophages circulating in the peripheral blood are thought to be carriers of the parasite to distal sites. Depending on the infected sites of the body, there are three forms of leishmaniasis: cutaneous, mucocutaneous and visceral. Leishmaniasis is a disease for which we still lack effective, affordable and easy to use drugs. In addition, surveillance and control are also neglected. This thesis summarizes the results of several projects using different approaches for parasite load measurement in the mouse model of leishmaniasis, including two methods that were developed and optimized in our laboratory. Detection and quantification of pathogens belongs to the major topics of the research of various infectious diseases. This parameter is necessary for confirmation of the diagnosis, characterization...Metody detekce a kvantifikace parazitů rodu Leishmania jako nástroj pro studium vzájemného působení patogenu, vektoru a hostitele Leishmaniáza je u lidí působena 21 druhem vnitrobuněčného jednobuněčného parazita rodu Leishmania, který je přenášen přibližně 30 druhy flebotomů. Kromě člověka jsou leishmánie schopné infikovat celou řadu obratlovců. Hlavní hostitelskou buňkou, v níž se parazit množí, je makrofág; posléze leishmánie buňku ničí a infikují další buňky. Nakažené monocyty a makrofágy cirkulují v periferní krvi a roznášejí parazita do dalších orgánů a tkání. V závislosti na infikované část těla jsou rozlišovány tři typy leishmaniázy: kožní, kožně-slizniční a viscerální. Pro léčbu leishmaniázy stále ještě chybí účinné, dostupné a jednoduše aplikovatelné léky. Zanedbaná je také diagnostika a monitorování onemocnění. Tato disertační práce shrnuje výsledky několika projektů, ve kterých byly použity různé přístupy k určení množství parazitů v myším modelu leishmaniázy, včetně dvou metod, které byly vyvinuty a optimizovány v naší laboratoři. Detekce a kvantifikace patogenů patří k hlavním tématům výzkumu různých infekčních chorob. Tento parametr je nezbytný pro potvrzení diagnózy, charakterizaci imunitní odpovědi hostitele a komplexních patologických změn v nakaženém organismu, a také pro posouzení...Department of Cell BiologyKatedra buněčné biologieFaculty of SciencePřírodovědecká fakult

Acrylonitrile Induction of Rodent Neoplasia: Potential Mechanism of Action and Relevance to Humans

Acrylonitrile, an industrial chemical, is a multisite carcinogen in rats and mice, producing tumors in four tissues with barrier function, that is, brain, forestomach, Zymbal’s gland, and Harderian gland. To assess mechanism(s) of action (MoA) for induction of neoplasia and to evaluate whether the findings in rodents are indicative of human hazard, data on the potential key effects produced by acrylonitrile in the four rodent target tissues of carcinogenicity were evaluated. A notable finding was depletion of glutathione in various organs, including two target tissues, the brain, and forestomach, suggesting that this effect could be a critical initiating event. An additional combination of oxidative DNA damage and cytotoxic effects of acrylonitrile and its metabolites, cyanide, and 2-cyanoethylene oxide, could initiate pro-inflammatory signaling and sustained cell and tissue injury, leading to compensatory cell proliferation and neoplastic development. The in vivo DNA-binding and genotoxicity of acrylonitrile has been studied in several target tissues with no compelling positive results. Thus, while some mutagenic effects were reported in acrylonitrile-exposed rodents, data to determine whether this mutagenicity stems from direct DNA reactivity of acrylonitrile are insufficient. Accordingly, the induction of tumors in rodents is consistent primarily with a non-genotoxic MoA, although a contribution from weak mutagenicity cannot be ruled out. Mechanistic data to support conclusions regarding human hazard from acrylonitrile exposure is weak. Comparison of metabolism of acrylonitrile between rodents and humans provide little support for human hazard. Three of the tissues affected in bioassays (forestomach, Zymbal’s gland, and Harderian gland) are present only in rodents, while the brain is anatomically different between rodents and humans, diminishing relevance of tumor induction in these tissues to human hazard. Extensive epidemiological data has not revealed causation of human cancer by acrylonitrile

Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk

Commonly consumed foods and beverages can contain chemicals with reported carcinogenic activity in rodent models. Moreover, exposures to some of these substances have been associated with increased cancer risks in humans. Food-borne carcinogens span a range of chemical classes and can arise from natural or anthropogenic sources, as well as form endogenously. Important considerations include the mechanism(s) of action (MoA), their relevance to human biology, and the level of exposure in diet. The MoAs of carcinogens have been classified as either DNA-reactive (genotoxic), involving covalent reaction with nuclear DNA, or epigenetic, involving molecular and cellular effects other than DNA reactivity. Carcinogens are generally present in food at low levels, resulting in low daily intakes, although there are some exceptions. Carcinogens of the DNA-reactive type produce effects at lower dosages than epigenetic carcinogens. Several food-related DNA-reactive carcinogens, including aflatoxins, aristolochic acid, benzene, benzo[a]pyrene and ethylene oxide, are recognized by the International Agency for Research on Cancer (IARC) as causes of human cancer. Of the epigenetic type, the only carcinogen considered to be associated with increased cancer in humans, although not from low-level food exposure, is dioxin (TCDD). Thus, DNA-reactive carcinogens in food represent a much greater risk than epigenetic carcinogens

Epigenetic Events Determine Tissue-Specific Toxicity of Inhalational Exposure to the Genotoxic Chemical 1,3-Butadiene in Male C57BL/6J Mice

1,3-Butadiene (BD), a widely used industrial chemical and a ubiquitous environmental pollutant, is a known human carcinogen. Although genotoxicity is an established mechanism of the tumorigenicity of BD, epigenetic effects have also been observed in livers of mice exposed to the chemical. To better characterize the diverse molecular mechanisms of BD tumorigenicity, we evaluated genotoxic and epigenotoxic effects of BD exposure in mouse tissues that are target (lung and liver) and non-target (kidney) for BD-induced tumors. We hypothesized that epigenetic alterations may explain, at least in part, the tissue-specific differences in BD tumorigenicity in mice. We evaluated the level of N-7-(2,3,4-trihydroxybut-1-yl)guanine adducts and 1,4-bis-(guan-7-yl)-2,3-butanediol crosslinks, DNA methylation, and histone modifications in male C57BL/6 mice exposed to filtered air or 425 ppm of BD by inhalation (6 h/day, 5 days/week) for 2 weeks. Although DNA damage was observed in all three tissues of BD-exposed mice, variation in epigenetic effects clearly existed between the kidneys, liver, and lungs. Epigenetic alterations indicative of genomic instability, including demethylation of repetitive DNA sequences and alterations in histone-lysine acetylation, were evident in the liver and lung tissues of BD-exposed mice. Changes in DNA methylation were insignificant in the kidneys of treated mice, whereas marks of condensed heterochromatin and transcriptional silencing (histone-lysine trimethylation) were increased. These modifications may represent a potential mechanistic explanation for the lack of tumorigenesis in the kidney. Our results indicate that differential tissue susceptibility to chemical-induced tumorigenesis may be attributed to tissue-specific epigenetic alterations

Genetics of Host Response to Leishmania tropica in Mice – Different Control of Skin Pathology, Chemokine Reaction, and Invasion into Spleen and Liver

Several hundred million people are exposed to the risk of leishmaniasis, a disease caused by intracellular protozoan parasites of several Leishmania species and transmitted by phlebotomine sand flies. In humans, L. tropica causes cutaneous form of leishmaniasis with painful and long-persisting lesions in the site of the insect bite, but the parasites can also penetrate to internal organs. The relationship between the host genes and development of the disease was demonstrated for numerous infectious diseases. However, the search for susceptibility genes in the human population could be a difficult task. In such cases, animal models may help to discover the role of different genes in interactions between the parasite and the host. Unfortunately, the literature contains only a few publications about the use of animals for L. tropica studies. Here, we report an animal model suitable for genetic, pathological and drug studies in L. tropica infection. We show how the host genotype influences different disease symptoms: skin lesions, parasite dissemination to the lymph nodes, spleen and liver, and increase of levels of chemokines CCL2, CCL3 and CCL5 in serum

Distinct genetic control of parasite elimination, dissemination, and disease after Leishmania major infection

Elimination of pathogens is the basis of host resistance to infections; however, relationship between persisting pathogens and disease has not been clarified. Leishmania major infection in mice is an important model of host–pathogen relationship. Infected BALB/c mice exhibit high parasite numbers in lymph nodes and spleens, and a chronic disease with skin lesions, splenomegaly, and hepatomegaly, increased serum IgE levels and cytokine imbalance. Although numerous gene loci affecting these disease symptoms have been reported, genes controlling parasites’ elimination or dissemination have never been mapped. We therefore compared genetics of the clinical and immunologic symptomatology with parasite load in (BALB/c × CcS-11) F2 hybrids and mapped five loci, two of which control parasite elimination or dissemination. Lmr5 influences parasite loads in spleens (and skin lesions, splenomegaly, and serum IgE, IL-4, and IFNγ levels), and Lmr20 determines parasite numbers in draining lymph nodes (and serum levels of IgE and IFNγ), but no skin or visceral pathology. Three additional loci do not affect parasite numbers but influence significantly the disease phenotype—Lmr21: skin lesions and IFNγ levels, Lmr22: IL-4 levels, Lmr23: IFNγ levels, indicating that development of L. major-caused disease includes critical regulations additional to control of parasite spread

Methods for Leishmania parasite detection and quantificatio as a tool for study of the pathogen-vector-host interactions

Methods for Leishmania parasite detection and quantification as a tool for study of the pathogen-vector-host interactions Leishmaniasis in human is caused by total 21 species of the intracellular protozoan parasite Leishmania, which are transmitted by about 30 species of phlebotomine sand flies. Besides human, Leishmania can infect a number of vertebrate hosts. The major host cell is the macrophage, in which parasites multiply, eventually rupturing the cell and spreading to uninfected cells. Infected monocytes and macrophages circulating in the peripheral blood are thought to be carriers of the parasite to distal sites. Depending on the infected sites of the body, there are three forms of leishmaniasis: cutaneous, mucocutaneous and visceral. Leishmaniasis is a disease for which we still lack effective, affordable and easy to use drugs. In addition, surveillance and control are also neglected. This thesis summarizes the results of several projects using different approaches for parasite load measurement in the mouse model of leishmaniasis, including two methods that were developed and optimized in our laboratory. Detection and quantification of pathogens belongs to the major topics of the research of various infectious diseases. This parameter is necessary for confirmation of the diagnosis, characterization..