Uremic plasma impairs barrier function and depletes the tight junction protein constituents of intestinal epithelium

Am J Nephrol. 2012;36(5):438-43. doi: 10.1159/000343886. Epub 2012 Oct 31.

Abstract

Background: Chronic kidney disease (CKD) causes intestinal barrier dysfunction which by allowing influx of endotoxin and other noxious products contributes to the CKD-associated systemic inflammation and uremic toxicity. We have recently shown that intestinal barrier dysfunction in CKD animals is due to degradation of transcellular (claudin-1 and occludin) and intracellular (ZO1) constituents of epithelial tight junction (TJ). This study determined whether CKD-associated disruption of TJ is mediated by retained uremic toxins/metabolites and, if so, whether they are removed by hemodialysis.

Methods: The TJ-forming human enterocytes (T84 cells) were seeded on the Transwell plates and utilized when transepithelial electrical resistance (TER) exceeded 1,000 mΩ/cm(2) to ensure full polarization and TJ formation. The cells were then incubated for 24 h in media containing 10% pre- or posthemodialysis plasma from end-stage renal disease (ESRD) patients or healthy individuals. TER was then measured and cells were processed for Western blot and immunohistological analyses.

Results: Compared with the control plasma, incubation in media containing predialysis plasma from ESRD patients resulted in a marked drop in TER pointing to increased epithelial permeability. This was accompanied by significant reductions in claudin-1 (85%), occludin (15%), and ZO1 (70%) abundance. The severity of TJ damage and dysfunction was significantly less in cells exposed to the postdialysis in comparison to predialysis plasma. These findings point to the presence of as-yet unidentified product(s) in the uremic plasma capable of depleting epithelial TJ.

Conclusions: Exposure to uremic milieu damages the intestinal epithelial TJ and impairs its barrier function, events which are mediated by agents which are partially removed by hemodialysis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Enterocytes / physiology*
  • Humans
  • Intestinal Mucosa / physiology*
  • Kidney Failure, Chronic / blood
  • Plasma / physiology*
  • Tight Junction Proteins / physiology*
  • Uremia / blood

Substances

  • Tight Junction Proteins