Blastocystis hominis Infection and Intestinal Injury

Zuckerman, Marc J.; Watts, Mark; Ho, Hoi; Meriano, Frank V.

doi:10.1097/00000441-199408000-00006

Cited by 43 publications

(41 citation statements)

References 48 publications

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“…Intestinal inflammation and edema were reported in patients infected with Blastocystis (19,21,39,54). In a murine model, intense infiltration of inflammatory cells into the colon and inflammation with edematous lamina propria in the cecum and colon were reported following Blastocystis infection (26).…”

Section: Discussionmentioning

confidence: 99%

“…Reports have suggested that this parasite can cause acute and chronic gastroenteritis (31), and inflammation of the intestinal mucosa has been associated with Blastocystis infections (19,21,39,54). Intense infiltration of inflammatory cells in the colon was shown after Blastocystis infection in mice (26), and it was reported that Blastocystis modulates interleukin-8 (IL-8) response in intestinal epithelial cells (24); however, nothing is known about the parasitic virulence factors and the early events occurring in host cells following Blastocystis-host interactions.…”

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confidence: 99%

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Blastocystis rattiContains Cysteine Proteases That Mediate Interleukin-8 Response from Human Intestinal Epithelial Cells in an NF-κB-Dependent Manner

2008

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Blastocystis is a ubiquitous enteric protozoan found in the intestinal tracts of humans and a wide range of animals. Evidence accumulated over the last decade suggests association of Blastocystis with gastrointestinal disorders involving diarrhea, abdominal pain, constipation, nausea, and fatigue. Clinical and experimental studies have associated Blastocystis with intestinal inflammation, and it has been shown that Blastocystis has potential to modulate the host immune response. Blastocystis is also reported to be an opportunistic pathogen in immunosuppressed patients, especially those suffering from AIDS. However, nothing is known about the parasitic virulence factors and early events following host-parasite interactions. In the present study, we investigated the molecular mechanism by which Blastocystis activates interleukin-8 (IL-8) gene expression in human colonic epithelial T84 cells. We demonstrate for the first time that cysteine proteases of Blastocystis ratti WR1, a zoonotic isolate, can activate IL-8 gene expression in human colonic epithelial cells. Furthermore, we show that NF-B activation is involved in the production of IL-8. In addition, our findings show that treatment with the antiprotozoal drug metronidazole can avert IL-8 production induced by B. ratti WR1. We also show for the first time that the central vacuole of Blastocystis may function as a reservoir for cysteine proteases. Our findings will contribute to an understanding of the pathobiology of a poorly studied parasite whose public health importance is increasingly recognized.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Blastocystis rattiContains Cysteine Proteases That Mediate Interleukin-8 Response from Human Intestinal Epithelial Cells in an NF-κB-Dependent Manner

2008

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“…There are no reports of Blastocystis-associated dysentery, and it appears that the parasite is generally noninvasive, as indicated by endoscopy (43,76,329,330) and histology of experimentally infected animals (5,152,187). An interesting case study described Blastocystis trophozoites present in the liver abscess aspirate of a 63-year-old man with a 5-day history of fever and blood-tinged watery diarrhea (102).…”

Section: Infection and Diseasementioning

confidence: 99%

Extreme anoxia tolerance in embryos of the annual killifishAustrofundulus limnaeus: insights from a metabolomics analysis

Podrabsky

Lopez

Fan

et al. 2007

Journal of Experimental Biology

129

154

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SUMMARY The annual killifish Austrofundulus limnaeus survives in ephemeral pond habitats by producing drought-tolerant diapausing embryos. These embryos probably experience oxygen deprivation as part of their normal developmental environment. We assessed the anoxia tolerance of A. limnaeus embryos across the duration of embryonic development. Embryos develop a substantial tolerance to anoxia during early development, which peaks during diapause II. This extreme tolerance of anoxia is retained during the first 4 days of post-diapause II development and is then lost. Metabolism during anoxia appears to be supported mainly by production of lactate, with alanine and succinate production contributing to a lesser degree. Anoxic embryos also accumulate large quantities of γ-aminobutyrate (GABA), a potential protector of neural function. It appears that the suite of characters associated with normal development and entry into diapause II in this species prepares the embryos for long-term survival in anoxia even while the embryos are exposed to aerobic conditions. This is the first report of such extreme anoxia tolerance in a vertebrate embryo, and introduces a new model for the study of anoxia tolerance in vertebrates.

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“…In some cases the parasite has been reported to cause acute illness (Russo et al, 1988;Vannatta et al, 1985) and can be life threatening when present in immunocompromised individuals (Prasad et al, 2000). Endoscopic and permeability studies of the intestine in a cohort study of Blastocystis-infected immunocompetent individuals failed to find any significant intestinal inflammation or impairment of the intestinal permeability barrier (Zuckerman et al, 1994). Fresh Blastocystis isolates, though, have been demonstrated to cause significant cytopathology of Chinese hamster ovary cells (CHO), adenocarcinoma HT-29 cells and rat intestinal epithelia (IEC-6) cells in culture (Puthia et al, 2006;Walderich et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Biochemical characterization of a mitochondrial-like organelle from Blastocystis sp. subtype 7

et al. 2008

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A mitochondrion-like organelle (MLO) was isolated from isotonic homogenates of Blastocystis. The organelle sedimented at 5000 g for 10 min, and had an isopycnic density in sucrose of 1.2 g ml "1. Biochemical characterization enabled the demonstration of several key enzymes that allowed the construction of a metabolic pathway consisting of an incomplete Krebs cycle linked to the oxygen-sensitive enzymes pyruvate : NADP + oxidoreductase (PNO), acetate : succinate CoA transferase (ASCT) and succinate thiokinase (STK), which cumulatively are responsible for recycling CoA and generating ATP. The organelle differs from typical aerobic mitochondria in possessing an oxygen-sensitive PNO that can use FAD + or FMN + as electron acceptor but is inactive with NAD + , Spinacia oleracea ferredoxin or Clostridium pasteurianum ferredoxin. A gene with 77 % sequence similarity to the PNO mitochondrion precursor cluster from Euglena gracilis sp[Q941N5] was identified in the Blastocystis genome database. A second cluster with 56 % sequence similarity to the pyruvate : ferredoxin oxidoreductase (PFOR) from Trichomonas vaginalis was also identified, which is in agreement with the concept that the PNO gene arose through the fusion of a eubacterial gene for PFOR with the gene for NADPH : cytochrome p450 reductase. Hydrogenase activity was not detected under the conditions used in this study. The Blastocystis oranelle therefore demonstrates significant biochemical differences from traditional mitochondria and hydrogenosomes, but possesses features of both. Based upon the results of this study, the Blastocystis organelle falls into the category of a MLO.

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Blastocystis hominis Infection and Intestinal Injury

Cited by 43 publications

References 48 publications

Blastocystis rattiContains Cysteine Proteases That Mediate Interleukin-8 Response from Human Intestinal Epithelial Cells in an NF-κB-Dependent Manner

Blastocystis rattiContains Cysteine Proteases That Mediate Interleukin-8 Response from Human Intestinal Epithelial Cells in an NF-κB-Dependent Manner

Extreme anoxia tolerance in embryos of the annual killifishAustrofundulus limnaeus: insights from a metabolomics analysis

Biochemical characterization of a mitochondrial-like organelle from Blastocystis sp. subtype 7

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