Live probiotics protect intestinal epithelial cells from the effects of infection with enteroinvasive Escherichia coli (EIEC)

Because probiotics alone improved epithelial barrier function, we explored whether they might abrogate the deleterious effects of pathogens on this parameter

S Resta-Lenert


Scholarcy highlights

  • The colonic epithelium maintains a life long reciprocally beneficial interaction with the colonic microbiota
  • No significant bacterial overgrowth was observed over the duration of the experiment under all conditions tested
  • Effects of probiotic colonisation on intestinal epithelial cell barrier function To investigate any direct effects of probiotics on our cell line models, we selected Streptococcus thermophilus and Lactobacillus acidophilus, and exposed HT29/cl.19A and Caco-2 cells to each individual strain and to a combination of the two
  • The two probiotics were not toxic to the cell monolayers, as shown by viability measurements following incubation with various multiplicity of infection of bacteria for up to 48 hours compared with untreated controls
  • Spent medium from ST or LA cultures, Streptococcus thermophilus and Lactobacillus acidophilus killed with antibiotics, and heat inactivated probiotics failed to increase transepithelial resistance or decrease permeability to FITC
  • Even when ST/LA killed with antibiotics were added to the monolayers before Enteroinvasive E coli challenge, a condition that was as effective as live ST/LA in reducing EIEC adhesion, the level of invading organisms was not reduced compared with controls
  • By preventing invasion and extensive colonisation, probiotics considerably reduce the infective load and the oxidative stress that is in part responsible for the acute mucosal inflammation induced by enteric pathogens. Inhibition of oxidative stress at the site of mucosal infection might prevent epidermal growth factor receptor inactivation as observed as a consequence of acute in vitro infection with Enteroinvasive E coli or rotavirus. It is well known that epidermal growth factor and activation of the EGFr promote epithelial restitution after injury in several gastrointestinal pathological conditions and that EGF therapy produces improvement in colitis and gastric ulcers in both in vivo and in vitro models. EGF regulates cell motility, proliferation, and maintenance of cell size and shape. Our data show that probiotic pretreatment is able to preserve EGFr function that would otherwise be affected adversely by EIEC invasion

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