Article

High glucose concentration in isotonic media alters Caco-2 cell permeability

Division of Pharmaceutical Sciences, College of Pharmacy, University of Cincinnati, Cincinnati, OH, USA.
AAPS PharmSci 02/2003; 5(3):E24. DOI: 10.1208/ps050324
Source: PubMed

ABSTRACT 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).

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Available from: Giovanni M Pauletti, Aug 13, 2015
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    • "In addition to TEER measurements, the integrity of cell monolayer was assessed using the confocal microscope. Fig. 2 demonstrates tight junctions in the monolayer as visualised by using Alexa Fluor® 488 phalloidin to label F-actin (D'Souza et al., 2003). Actin cytoskeleton is a part of the structural proteins that are the major components of cell– cell adhesion complexes or tight junctions (Benedicto, Molina-Jiménez, Bartosch, et al., 2009). "
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    • "In addition to TEER measurements, the integrity of cell monolayer was assessed using the confocal microscope. Fig. 2 demonstrates tight junctions in the monolayer as visualised by using Alexa Fluor® 488 phalloidin to label F-actin (D'Souza et al., 2003). Actin cytoskeleton is a part of the structural proteins that are the major components of cell– cell adhesion complexes or tight junctions (Benedicto, Molina-Jiménez, Bartosch, et al., 2009). "
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    • "Second, at an environmental pH below 4, the diazepam ring of midazolam opens, forming a more polar primary amine derivative (Smith et al., 1981). Third, a high glucose concentration has been shown to disrupt the membrane integrity of Caco-2 cell monolayers (D'Souza et al., 2003). Taken together, these observations raised the possibility that sweetened cranberry juice E could alter the absorption of midazolam in vivo. "
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