Effect of Ostertagia circumcincta excretory/secretory products on gastrin release in vitro

Lawton, D.E.B.; Wigger, H. Joachim; Simcock, David C.; Simpson, H.V.

doi:10.1016/s0304-4017(01)00628-8

Cited by 11 publications

(13 citation statements)

References 39 publications

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“…The failure in this study of H. contortus ES products to stimulate gastrin secretion in vitro, together with a similar result with O. circumcincta incubates (Lawton et al 2002), strongly suggest that parasite ES products are not a major contributor to the hypergastrinaemia of abomasal parasitism. The second aim was to study the survival of H. contortus in different media, particularly in acidic conditions.…”

Section: Discussionmentioning

confidence: 48%

“…Previous experiments with Ostertagia circumcincta ES products failed to show any increase in gastrin secretion by ovine antral tissue pieces in vitro (Lawton et al 2002). In the present study, similar products were collected from the larger Haemonchus contortus, the other important gastric parasite of sheep, which, because of its greater size, may generate larger amounts of ES products in appropriate media.…”

Section: Introductionmentioning

confidence: 89%

“…The ovine antral mucosal preparation previously described by Lawton et al (2000Lawton et al ( , 2002 was used to test the effects of ES products on gastrin secretion. Eight replicate tissue pieces were incubated at 37°C, first for three 10 min periods in control medium followed by three periods in the test solution.…”

Section: In Vitro Gastrin Secretionmentioning

confidence: 99%

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The failure of Haemonchus contortus excretory/secretory products to stimulate gastrin secretion in vitro

2004

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Excretory/secretory (ES) products collected from exsheathed L3 or parasitic stages of Haemonchus contortus were tested in vitro for gastrin stimulatory properties using an ovine abomasal antral mucosal preparation. In addition, the motility of exsheathed L3 and parasites recovered on weeks 2, 6 and 8 post-infection was studied in water, saline, saline with glucose or ovine blood and in HBSS pH 2.5-7.4. Parasitic stages became immotile rapidly in water and HBSS pH 2.5, more slowly in HBSS pH 3.5, but nearly 100% remained motile for 48 h when blood was included in the medium. Exsheathed L3 motility was reduced only by water and HBSS pH 2.5, and then only in the second week of incubation. Gastrin secretion was not consistently increased by any of the parasite ES products tested in vitro, therefore, they probably do not stimulate the G cell directly to produce the hypergastrinaemia seen in parasitised sheep.

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Section: Discussionmentioning

confidence: 48%

Section: Introductionmentioning

confidence: 89%

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The failure of Haemonchus contortus excretory/secretory products to stimulate gastrin secretion in vitro

2004

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“…Studies with adult worms of both H. contortus and Ostertagia spp. have reported that motility is maintained for extended periods at pH 4.5 and above rather than at low pH, whereas exsheathed L3 of both species remained motile for days at pH 2.5 (Eiler et al 1981;Haag 1995;Lawton et al 2002). Therefore, it is also possible that larval stages may release different products at a lower pH (Lawton et al 2002), whereas the medium used in these studies was routinely adjusted to a pH of 7.4.…”

Section: Discussionmentioning

confidence: 89%

Effects of excretory/secretory products of Haemonchus contortus on cell vacuolation

et al. 2005

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Excretory/secretory (ES) products of the gastric nematode, Haemonchus contortus, have been implicated in the inhibition of gastric acid secretion which follows infection. Parietal cell vacuolation has been observed in abomasal sections from parasitised sheep, and ES prepared in vitro has been reported to cause vacuolation and to increase neutral red (NR) uptake in epithelial cell cultures. We have used the latter approach to examine, at the cellular level, the effects of ES prepared from L3 and adult nematodes. Both NR uptake and cellular vacuolation were increased following exposure to larval or adult ES products. ES preparations from adult worms induced more extensive vacuolation then those from L3 worms and, as with VacA treatment, adherent cells remained viable despite high levels of vacuolation. Whereas VacA-induced vacuolation resulted in NR uptake predominantly localised in vacuoles, this appeared not to be the case with ES-induced vacuolation, suggesting that different mechanisms might be involved. Both ES and VacA exposure was associated with an increased rate of cell detachment.

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“…Parasite ES products involved in the host-parasite interaction, particularly those which facilitate the establishment and maintenance of the parasite in the host, are attractive candidates for anthelmintic therapies. Unlike L3, L4 and adult worms of the sheep abomasal nematode parasites Ostertagia (Teladorsagia) circumcincta and Haemonchus contortus are rapidly killed in vitro at pH 2.5 and 3.5 (Haag 1995;Lawton et al 2002), suggesting that the typical inhibition of acid secretion in the parasitised abomasum may be beneficial to the worms.…”

Section: Introductionmentioning

confidence: 91%

Excretory/secretory products of sheep abomasal nematode parasites cause vacuolation and increased neutral red uptake by HeLa cells

et al. 2005

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Excretory/secretory (ES) products of Ostertagia (Teladorsagia) circumcincta and Haemonchus contortus have been implicated in the inhibition of gastric acid secretion and vacuolation, and the loss of parietal cells associated with abomasal parasitism. Vacuolation of epithelial (HeLa) cells caused by adult O. circumcincta or L3 O. circumcincta or H. contortus ES products have been examined by differential interference contrast microscopy and by the neutral red uptake assay. ES products caused visible vacuolation of HeLa cells, and this effect was enhanced by 8 mM NH4Cl. Some parasite ES products caused a marked detachment of cells from the coverslip. At lower concentrations of ES products, neutral red uptake was usually increased above the control, but at higher concentrations of ES products, uptake was often decreased, probably because of cell detachment. Although generally consistent with direct observations of HeLa cell vacuolation by parasite chemicals, neutral red uptake was not a satisfactory quantitative assay.

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Effect of Ostertagia circumcincta excretory/secretory products on gastrin release in vitro

Cited by 11 publications

References 39 publications

The failure of Haemonchus contortus excretory/secretory products to stimulate gastrin secretion in vitro

The failure of Haemonchus contortus excretory/secretory products to stimulate gastrin secretion in vitro

Effects of excretory/secretory products of Haemonchus contortus on cell vacuolation

Excretory/secretory products of sheep abomasal nematode parasites cause vacuolation and increased neutral red uptake by HeLa cells

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