Trans-epithelial transport of compounds across an intestinal epithelial barrier

Intestinal trans-epithelial transport, membrane transport, apparent permeability coefficient, bioavailability, Caco-2 cell line
Figure 1: Cross-section of a Transwell®-Chamber: semi-permeable membrane covered with a cell monolayer

Intestinal trans-epithelial transport, membrane transport, apparent permeability coefficient, bioavailability, Caco-2 cell line
Figure 2: Apparent permeabilization coefficient of selected compounds

Species

The colorectal adenocarcinoma cell line Caco-2 is an established cell line to investigate in the intestinal trans-epithelial transport of compounds.

Field of application:

The barrier function of intestinal epithelium is critical for the bioavailability of nutrients as well as for pharmaceutical substances. The assay is performed in Transwell chambers®. In each cavity of the chambers Caco-2 cells are growing on semi-permeable membranes which divide the cavity in an apical and a basolateral compartment. During the cultivation time of 21 days the cells differentiate to cells with similar morphological and functional characteristics (e.g. transport proteins, digestion enzymes) to the human intestine. After incubation of the cells with substances their transport rate can be examined by taking samples from both compartments.

This model can be used for the following fields of application:

  • Calculation of the transport velocity of substances across the epithelial barrier
  • Estimation of bioavailability of substances in vivo

Endpoints/Outcome parameter

Calculation of apparent permeability coefficient (Papp). Based on Papp values the transport rate / velocity of substances can be categorized in low, media or high transported substances across intestinal epithelium.

Readout parameter

Samples are taken from the apical and basolateral compartment during the assay and analyzed by LC-MS. Transported amounts across the epithelial barrier will be calculated.

Quality management and validation

  • Substance specific method development and validation for LC-MS
  • For each test series a control compound with known Papp value is used
  • Internal quality management
  • Both the cell assay and the analysis of the samples can be performed according to GLP

Weblink(s)

https://www.izi.fraunhofer.de/de/departments/halle-location/department-of-drug-design-and-target-validation/molecular-biotechnology.html#tabpanel-2

References

  • Geissler S et al. (2010) The bioactive dipeptide anserine is transported by human proton-coupled peptide transporters. FEBS J 277(3):790-795

  • Geissler S et al. (2011) Synthesis and intestinal transport of the iron chelator maltosine in free and dipeptide form. Eur J Pharm Biopharm 78(1):75-82