PLoS ONE (Jan 2013)

Chronic alcohol exposure renders epithelial cells vulnerable to bacterial infection.

  • Stephen Wood,
  • Ravi Pithadia,
  • Tooba Rehman,
  • Lijuan Zhang,
  • Jennifer Plichta,
  • Katherine A Radek,
  • Christopher Forsyth,
  • Ali Keshavarzian,
  • Sasha H Shafikhani

DOI
https://doi.org/10.1371/journal.pone.0054646
Journal volume & issue
Vol. 8, no. 1
p. e54646

Abstract

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Despite two centuries of reports linking alcohol consumption with enhanced susceptibility to bacterial infections and in particular gut-derived bacteria, there have been no studies or model systems to assess the impact of long-term alcohol exposure on the ability of the epithelial barrier to withstand bacterial infection. It is well established that acute alcohol exposure leads to reduction in tight and adherens junctions, which in turn leads to increases in epithelial cellular permeability to bacterial products, leading to endotoxemia and a variety of deleterious effects in both rodents and human. We hypothesized that reduced fortification at junctional structures should also reduce the epithelial barrier's capacity to maintain its integrity in the face of bacterial challenge thus rendering epithelial cells more vulnerable to infection. In this study, we established a cell-culture based model system for long-term alcohol exposure to assess the impact of chronic alcohol exposure on the ability of Caco-2 intestinal epithelial cells to withstand infection when facing pathogenic bacteria under the intact or wounded conditions. We report that daily treatment with 0.2% ethanol for two months rendered Caco-2 cells far more susceptible to wound damage and cytotoxicity caused by most but not all bacterial pathogens tested in our studies. Consistent with acute alcohol exposure, long-term ethanol exposure also adversely impacted tight junction structures, but in contrast, it did not affect the adherens junction. Finally, alcohol-treated cells partially regained their ability to withstand infection when ethanol treatment was ceased for two weeks, indicating that alcohol's deleterious effects on cells may be reversible.