title: Clinical relevance of intestinal peptide uptake.
abstract: OBJECTIVE
  To determine available information on an independent peptide transporter 1 (PepT1) and its potential relevance to treatment, this evaluation was completed.
  
  
  METHODS
  Fully published English language literature articles sourced through PubMed related to protein digestion and absorption, specifically human peptide and amino acid transport, were accessed and reviewed. Papers from 1970 to the present, with particular emphasis on the past decade, were examined. In addition, abstracted information translated to English in PubMed was also included. Finally, studies and reviews relevant to nutrient or drug uptake, particularly in human intestine were included for evaluation. This work represents a summary of all of these studies with particular reference to peptide transporter mediated assimilation of nutrients and pharmacologically active medications.
  
  
  RESULTS
  Assimilation of dietary protein in humans involves gastric and pancreatic enzyme hydrolysis to luminal oligopeptides and free amino acids. During the ensuing intestinal phase, these hydrolytic products are transported into the epithelial cell and, eventually, the portal vein. A critical component of this process is the uptake of intact di-peptides and tri-peptides by an independent PepT1. A number of "peptide-mimetic" pharmaceutical agents may also be transported through this carrier, important for uptake of different antibiotics, antiviral agents and angiotensin-converting enzyme inhibitors. In addition, specific peptide products of intestinal bacteria may also be transported by PepT1, with initiation and persistence of an immune response including increased cytokine production and associated intestinal inflammatory changes. Interestingly, these inflammatory changes may also be attenuated with orally-administered anti-inflammatory tripeptides administered as site-specific nanoparticles and taken up by this PepT1 transport protein.
  
  
  CONCLUSIONS
  Further evaluation of the role of this transporter in treatment of intestinal disorders, including inflammatory bowel disease is needed.
authors.affiliation: Hugh James Freeman, Department of Medicine, University of British Columbia, Vancouver V6T 1W5, Canada.
authors.forename: Hugh James
authors.initials: HJ
authors.lastname: Freeman
keywords: Bacterial peptides; Dietary peptides; Drug absorption; Intestinal inflammation; Peptide transport; Peptide transporter 1