High glucose concentration in isotonic media alters caco-2 cell permeability.
Caco-2 cell permeability was evaluated in isotonic media containing high (25 mM) or physiological (5.5 mM) glucose concentrations. Transepithelial electrical resistance (TEER) and membrane fluidity were measured to assess glucose-induced alterations in physical barrier properties. In parallel, distribution of the actin filament (F-actin) and zonula occludens-1 (ZO-1) proteins was assessed by confocal microscopy. Transepithelial fluxes of mannitol, hydrocortisone, digoxin, and glycyl sarcosine (Gly-Sar) that permeate the intestinal mucosa by various pathways were measured to quantify the effect of glucose-induced changes on Caco-2 cell permeability. High glucose decreased maximum TEER of cell monolayers by 47%, whereas membrane fluidity at the hydrophobic core and lipid/polar head interphase was significantly increased. F-actin distribution in high glucose cells appeared more diffuse while ZO-1 was unchanged. Mannitol and hydrocortisone fluxes across Caco-2 cells cultured in high glucose increased by 65% and 24%, respectively. In addition, high glucose decreased the maximum transport capacity (Vmax) of PepT-1. P-glycoprotein activity, however, was unchanged. In conclusion, high extracellular glucose concentration in isotonic media significantly alters physical barrier properties of Caco-2 cell monolayers, which predominantly affects transepithelial transport of solutes permeating the cell barrier by paracellular and transcellular passive diffusion and facilitated transport mediated by the proton-dependent oligopeptide transporter (PepT-1).
D'Souza
Vanessa M
VM
Division of Pharmaceutical Sciences, College of Pharmacy, University of Cincinnati, Cincinnati, OH, USA.
Shertzer
Howard G
HG
Menon
Anil G
AG
Pauletti
Giovanni M
GM
D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells / Q000187:drug effects* / Q000502:physiology; D002463:Cell Membrane Permeability / Q000187:drug effects*; D005947:Glucose / Q000008:administration & dosage* / Q000494:pharmacology; D006801:Humans; D008560:Membrane Fluidity / Q000187:drug effects
D005947:Glucose