Cellular damage induced by toxins from H. pylori strains isolated from clinical cases

ESCOBAR F.; MATTANA C.; SABINI L.; DEMO M.

Villa General Belgrano, Córdoba

Jornada; XIV Jornadas de Biologia; 2003

Helicobacter pylory infection leads to different clinical and pathological outcomes in humans including chronic gastritis, peptic ulcer disease and gastric neoplasia. A major virulence factor produced by H. pylori is a cytotoxin, termed VacA, which causes vacuolar degeneration of cells in vitro but only about 50% of H. pylori isolate can produce the vacuolating toxin. This consideration led us to analyze the H. pylori toxins activity from 18 strains recovered from patients with gastric simptomatology. Culture supernatants were collected, concentrated 30X and sterilized by filtration. Vero cells were inoculated with two fold toxin dilutions in Minimum Essential Medium containing or not 10 mM ClNH4, and incubated at 37ºC, 5 days. The effects of the toxin were analyzed by light microscopy and documented by photographs. Exposure of culture cells to the toxins led to structural alterations with marked vacuolation and peripherical nuclear displacement. Data indicated a 72% of positivity (toxin titers range from 5 to ≥ 640). These findings demonstrate the incidence of H. pylori strains with capacity to produce vacuolating toxin associated to severe gastric damages.