Elsevier

Surgery

Volume 121, Issue 6, June 1997, Pages 668-680
Surgery

Original communication
Acidic conditions ameliorate both adenosine triphosphate depletion and the development of hyperpermeability in cultured Caco-2BBe enterocytic monolayers subjected to metabolic inhibition

https://doi.org/10.1016/S0039-6060(97)90056-8Get rights and content

Abstract

Background. We recently reported that moderate degrees of adenosine triphosphate (ATP) depletion induced by chronic glycolytic inhibition or hypoxia increase the permeability of Caco-2BBe enterocytic monolayers. Interestingly, the development of lactic acidosis induced by anaerobic glycolysis ameliorates the development of hyperpermeability caused by chronic ATP depletion. We sought to further elucidate the mechanism(s) responsible for the apparent protection against epithelial hyperpermeability afforded by mild acidosis under conditions of metabolic inhibition.

Methods. Caco-2BBe monolayers growing on permeable supports in bicameral chambers were incubated with 2-deoxyglucose (2DOG) in a glucose-free (Glu-) environment to inhibit glycolysis. Permeability was determined by measuring the transepithelial flux of fluorescein sulfonic acid. Concentrations of intracellular calcium [Ca2+]i were determined fluorometrically by using fura-2.

Results. When extracellular pH (pH0) was maintained at 7.4 or 5.5, incubation of monolayers for 24 hours with Glu-/2DOG increased permeability and depleted intracellular ATP levels. However, keeping pH0 at 7.0 to 6.0 ameliorated both the development of hyperpermeability and the depletion of ATP induced by Glu-/2DOG. These protective effects were observed under acidic conditions created either by addition to the medium of HCl or by incubation under an atmosphere containing 20% CO2. Incubation with Glu-/2DOG caused bulging of the apical membranes of cells (electron microscopy) and derangements in the perijunctional distribution of actin (fluorescence microscopy); however, these structural changes were ameliorated by mild acidosis. Acute chemical hypoxia at pH0 7.4 induced by Glu-/2DOG plus antimycin A decreased cellular ATP levels and elevated [Ca2+]i. Lowering pH0 to 6.8 ameliorated both the depletion of ATP and the increase in [Ca2+]i induced by Glu-/2DOG + antimycin A.

Conclusions. Moderate decreases in pH ameliorate the hyperpermeability induced by metabolic inhibition, possibly by diminishing ATP depletion and blunting increases in [Ca2+]i.

References (53)

  • DC Harrison et al.

    A pH-dependent phospholipase A2 contributes to loss of plasma membrane integrity during chemical hypoxia in rat hepatocytes

    Biochem Biophys Res Commun

    (1991)
  • JL Madara et al.

    Interferon-y directly affects barrier function of cultured intestinal epithelial monolayers

    J Clin Invest

    (1989)
  • RB Adams et al.

    IFN-y modulation of epithelial barrier function: time course, reversibility, and site of cytokine binding

    J Immunol

    (1993)
  • N Unno et al.

    Nitric oxide mediates interferon-gamma-induced hyperpermeability in cultured human intestinal epithelial monolayers

    Crit Care Med

    (1995)
  • SP Colgan et al.

    IL-4 directly modulates function of a model human intestinal epithelium

    J Immunol

    (1994)
  • JA McRoberts et al.

    Insulin regulates the paracellular permeability of cultured intestinal epithelial cell monolayers

    J Clin Invest

    (1990)
  • JA McRoberts et al.

    Regulation of T84 cell monolayer permeability by insulin-like growth factors

    Am J Physiol

    (1992)
  • WF Stenson et al.

    Regulation of paracellular permeability in Caco-2 cell monolayers by protein kinase C

    Am J Physiol

    (1993)
  • AL Salzman et al.

    Nitric oxide dilates tight junctions and depletes ATP in cultured Caco-2BBe intestinal epithelial monolayers

    Am J Physiol

    (1995)
  • PE Canfield et al.

    Effect of reversible ATP depletion on tight-junction integrity in LLC-PK1 cells

    Am J Physiol

    (1991)
  • JB Matthews et al.

    “Chemical hypoxia” increases junctional permeability and activates chloride transport in human intestinal epithelial monolayers

    Surgery

    (1994)
  • LJ Mandel et al.

    Uncoupling of the molecular ‘fence’ and paracellular ‘gate’ functions in epithelial tight junctions

    Nature

    (1993)
  • N Unno et al.

    Hyperpermeability and ATP depletion induced by chronic hypoxia or glycolytic inhibition in Caco-2BBe monolayers

    Am J Physiol

    (1996)
  • AL Salzman et al.

    Endotoxin-induced ileal mucosal hyperpermeability in pigs: role of tissue acidosis

    Am J Physiol

    (1994)
  • Menconi MJ, Salzman AL, Unno N, et al. Acidosis induces hyperpermeability in Caco-2BBe cultured intestinal epithelial...
  • M Winter et al.

    The conductance of cultured epithelial cell monolayers: oxidants, adenosine triphosphate, and phorbol dibutyrate

    Am J Respir Cell Mol Biol

    (1990)
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    Supported in part by grant GM37631 from the National Institutes of Health (NIH). Dr. Unno was supported by Uehara Memorial Foundation (Japan). Dr. Hagen was supported in part by grant DK 15081 from the NIH and in part by the morphology core of the Harvard Digestive Disease Center (NIH grant DK 34854).

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