Entamoeba histolytica: Mechanism of decrease of virulence of axenic cultures maintained for prolonged periods

Olivos, Alfonso; Ramos, Espiridión; Néquiz, Mario; Barba-Ostria, Carlos; Tello, Eusebio; Castañón, Guadalupe; González, Augusto; Martı́nez, Rubén D.; Montfort, Irmgard; Pérez-Tamayo, Ruy

doi:10.1016/j.exppara.2005.03.020

Cited by 26 publications

(30 citation statements)

References 15 publications

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“…To examine the host stressors involved in the early elimination of nv Eh or E. dispar from the liver after their intraportal injection in hamsters, the clearance time of the three types of amoebae was first established. After 1 h of infection, v Eh , nv Eh and E. dispar were visible within the tissue, in contact with liver cells and surrounded by few inflammatory cells, as previously described (Olivos et al ., ). After 24 h post‐infection, nv Eh and E dispar were completely eliminated, whereas v Eh survived and caused tissue damage (Supporting Information http://onlinelibrary.wiley.com/doi/10.1111/cmi.12419/suppinfo).…”

Section: Resultsmentioning

confidence: 97%

Maintenance of intracellular hypoxia and adequate heat shock response are essential requirements for pathogenicity and virulence ofEntamoeba histolytica

et al. 2015

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SummaryAdhesion to cells, cytotoxicity and proteolysis are functions required for virulence and pathogenicity of Entamoeba histolytica. However, there was no correlation between these in vitro functions and the early elimination of non-pathogenic E. dispar and non-virulent E. histolytica (nvEh) in experimental amoebic liver abscesses developed in hamsters. Thus, additional functions may be involved in amoebic pathogenicity and virulence. In the present study, an integral experimental assessment, including innovative technologies for analyses of amoebal pathophysiology, cell biology, biochemistry and transcriptomics, was carried out to elucidate whether other cellular processes are involved in amoebal pathogenicity and virulence. In comparison with virulent E. histolytica, the data indicated that the main reasons for the early clearance of nvEh from hamster liver are decreased intracellular H 2O2 detoxification rate and deficient heat shock protein expression, whereas for E. dispar, it is a relatively lower capacity for O2 reduction. Therefore, maintenance of an intracellular hypoxic environment combined with the induction of an adequate parasite response to oxidative stress are essential requirements for Entamoeba survival in the liver, and therefore for pathogenicity.

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Section: Resultsmentioning

confidence: 97%

Maintenance of intracellular hypoxia and adequate heat shock response are essential requirements for pathogenicity and virulence ofEntamoeba histolytica

et al. 2015

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“…It is interesting to speculate about the mechanism by which Ascaridole kills trophozoites. It is an endoperoxide that it can deliver reactive oxygen species and damage the trophozoites in a similar way that oxygen peroxide induces toxicity to amoeba [30]. Recently, Monzote et al [31] reported the toxic effects of Chenopodium essential oil and its components on some protozoa as Leishmania , Trypanosoma brucei, and Trypanosoma cruzi , and they concluded that the Ascaridole exhibited the better antileishmanial activity and suggest that the action mechanism through the generation of oxygen radicals, mitochondrial dysfunction, and a modification of redox indexes.…”

Section: Resultsmentioning

confidence: 99%

Amoebicidal Activity of Essential Oil of Dysphania ambrosioides (L.) Mosyakin & Clemants in an Amoebic Liver Abscess Hamster Model

Ávila-Blanco

Rodriguez

Duque

et al. 2014

Evidence-Based Complementary and Alternative Medicine

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Amebiasis is a parasitic disease that extends worldwide and is a public health problem in developing countries. Metronidazole is the drug recommended in the treatment of amebiasis, but its contralateral effects and lack of continuity of treatment induce low efficiency, coupled with the appearance of resistant amoebic strains. Therefore, the search of new compounds with amoebicidal activity is urgent and important. In this study, we evaluated the in vitro and in vivo antiamoebic activity of the essential oil Dysphania ambrosioides (L.) Mosyakin & Clemants. It exhibited an IC50 = 0.7 mg/mL against trophozoites. The oral administration of essential oil (8 mg/kg and 80 mg/kg) to hamster infected with Entamoeba histolytica reverted the infection. Ascaridole was identified as the main component of essential oil of D. ambrosioides. The identification of amoebicidal activity of Ascaridole gives support to the traditional use. Further studies with Ascaridole will be carried out to understand the mechanism involved.

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“…The difference at the genetic level between trophozoites able to cause intestinal or hepatic disease would partly explain the rare occurrence of intestinal symptoms in patients that present ALA (1). Trophozoites from patients can be purified and cultured in vitro, during which time their ability to form ALA in animals decreases (60,81). However, recurrent passage into animals maintains parasite virulence (59) and involves mechanisms that are still under investigation.…”

Section: Key Amoebic Factors In the Development Of Liver Abscessesmentioning

confidence: 99%

Host-Microbe Interactions and Defense Mechanisms in the Development of Amoebic Liver Abscesses

2009

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SUMMARY Amoebiasis by Entamoeba histolytica is a major public health problem in developing countries and leads to several thousand deaths per year. The parasite invades the intestine (provoking diarrhea and dysentery) and the liver, where it forms abscesses (amoebic liver abscesses [ALAs]). The liver is the organ responsible for filtering blood coming from the intestinal tract, a task that implies a particular structure and immune features. Amoebae use the portal route and break through the sinusoidal endothelial barrier to reach the hepatic parenchyma. When faced with systemic and cell-mediated defenses, trophozoites adapt to their new environment and modulate host responses, leading to parasite survival and the formation of inflammatory foci. Cytopathogenic effects and the onset of inflammation may be caused by diffusible products originating from parasites and/or immune cells either by their secretion or by their release after cell death. Liver infection thus results from the interplay between E. histolytica and hepatic cells. Despite its importance in terms of public health burden, the lack of integrated data on ALA genesis means that we have only an incomplete description of the initiation and development of hepatic amoebiasis. Here, we review the main steps of ALA development as well as the responses triggered in both the host and the parasite. Transcriptome studies highlighted parasite factors involved in adherence to human cells, cytopathogenic effects, and adaptative and stress responses. An understanding of their role in ALA development will help to unravel the host-pathogen interactions and their evolution throughout the infection.

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Entamoeba histolytica: Mechanism of decrease of virulence of axenic cultures maintained for prolonged periods

Cited by 26 publications

References 15 publications

Maintenance of intracellular hypoxia and adequate heat shock response are essential requirements for pathogenicity and virulence ofEntamoeba histolytica

Maintenance of intracellular hypoxia and adequate heat shock response are essential requirements for pathogenicity and virulence ofEntamoeba histolytica

Amoebicidal Activity of Essential Oil of Dysphania ambrosioides (L.) Mosyakin & Clemants in an Amoebic Liver Abscess Hamster Model

Host-Microbe Interactions and Defense Mechanisms in the Development of Amoebic Liver Abscesses

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