Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/3/2004
Publication Date: 7/25/2004
Citation: Shappell, N.W., Smith, D.J. 2004. Ergovaline transport across human gastrointestinal cells (caco-2). [abstract] Joint Meeting of American Society of Animal Science, American Dairy Science Association, and Poultry Science Association, St. Louis, MO, July 25-29, 2004, Journal of Animal Science 82(Suppl 1):181, Abstract T71.
Technical Abstract: The gastrointestinal (GI) cell model Caco-2 (derived from human colon carcinoma) was used to assess ergovaline transport. Cells were grown in transwell inserts until monolayers were established (~day 20 in culture). A pre-equilibrated mixture of ergovaline/ergovalinine (60:40; 10 and 40 M concentrations) was added to the apical wells (equivalent to mucosal side) in media containing phenol red. Basal media (equivalent to serosal side) contained no phenol red or ergovaline/inine. Diffusion of compounds through filters with no cells present was also measured. Apical and basal media were extracted, and isomer concentrations were determined by HPLC with fluorescence detection. Monolayer integrity was maintained throughout the 12h experimental period as assessed by the absence of phenol red in basal media. Kinetics of isomers were identical. In the absence of cells, basal accumulation of isomers was essentially linear for 3h at 10 and 40 M concentrations, after which basal accumulation plateaued (regression curves best described by ln equation; R2 from 0.85 to 0.96). A second order polynomial equation best described the regression analyses of basal isomer accumulation in the presence cells (R2 from 0.94 to 1.00). The linear phase of accumulation extended to 240 min with cells. Little change in basal accumulation was observed from 6-12h. After 6h in the presence of cells, ~25% and 40% of dose had accumulated in the basal compartment for 10 and 40 µM ergovaline, respectively. These experiments show that both ergovaline and its naturally occurring isomer, ergovalinine, readily cross GI mucosal cells intact and with similar kinetics. Because both isomers were transported, either isomer, or a combination of both, could be involved in the pathogenesis of fescue toxicosis at sites distal to the GI.