title: The angiotensin converting enzyme inhibitory tripeptides Ile-Pro-Pro and Val-Pro-Pro show increasing permeabilities with increasing physiological relevance of absorption models.
abstract: Transepithelial transport of the ACE inhibitory peptides Ile-Pro-Pro and Val-Pro-Pro was studied in different models of absorption. Apparent permeability (P(app)) values for absorptive transport across Caco-2 monolayers were 1.0+/-0.9 x 10(-8) (Ile-Pro-Pro) and 0.5+/-0.1 x 10(-8)cms(-1) (Val-Pro-Pro). Ex vivo transport across jejunal segments in the Ussing chamber was 5-times (Ile-Pro-Pro) to 10-times (Val-Pro-Pro) higher with no significant differences (p>0.05) observed between both peptides. The peptidase inhibitor bestatin increased permeability for the absorptive direction for Ile-Pro-Pro by twofold. Neither a transepithelial pH gradient nor increased apical tripeptide concentration nor longitudinal localization of the intestinal segment influenced P(app) in the ex vivo experiments. Val-Pro-Pro transport across Peyer's patches, however, was 4-times higher (P(app)=21.0+/-9.3 x10(-8)cms(-1)) as compared to duodenum (P(app)=4.8+/-1.4 x 10(-8)cms(-1)). In the in situ perfusion experiments P(app) values varied greatly among different animals ranging from 0.5 to 24.0 x10(-8)cms(-1) (Ile-Pro-Pro) and from 1.0 to 15.6 x 10(-8)cms(-1) (Val-Pro-Pro). In summary, Caco-2 and ex vivo absorption models differ considerably regarding their peptide permeability. The in situ model seems to be less appropriate because of the observed large variability in peptide permeability. The results of this study demonstrate that the ACE inhibitory peptides Ile-Pro-Pro and Val-Pro-Pro are absorbed partially undegraded.
authors.affiliation: Unilever Food and Health Research Institute, 3133 AT Vlaardingen, The Netherlands. martin.foltz@unilever.com
authors.forename: Martin
authors.initials: M
authors.lastname: Foltz
authors.forename: Anja
authors.initials: A
authors.lastname: Cerstiaens
authors.forename: Ans
authors.initials: A
authors.lastname: van Meensel
authors.forename: Raf
authors.initials: R
authors.lastname: Mols
authors.forename: Pieter C
authors.initials: PC
authors.lastname: van der Pijl
authors.forename: Guus S M J E
authors.initials: GS
authors.lastname: Duchateau
authors.forename: Patrick
authors.initials: P
authors.lastname: Augustijns
mesh_terms: D000042:Absorption; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D002853:Chromatography, Liquid; D015194:Diffusion Chambers, Culture; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*; D009924:Organ Culture Techniques; D051381:Rats
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D009842:Oligopeptides; C489032:isoleucyl-prolyl-proline; C489031:valyl-prolyl-proline