Biomarkers of Epithelial Mass, Intestinal Function, or Cellular Damage

1 Biomarkers of Epithelial Mass, Intestinal Function, or Cellular Damage 

1 Citmlline Citrulline, an intermediate in the urea cycle, is the nitrogen end product of glutamine metabolism. Since the small intestinal epithelium is the predominant site of glutamine uptake and metabolism, it is therefore the principal source of circulating citrulline (van de Poll et al., 2007), so damage to this tissue would be expected to 

3 Trefoil Factors Trefoil factors are cysteine-rich, mucin-associated peptides (MAPs) that are richly expressed in the GI tract and upregulated in inflammatory and erosive/ ulcerative conditions. Trefoil factor (TF) 1 is reportedly upregulated in ulcerated rat gastric mucosa (Ulaganathan et al., 2001), and TF 1 and TF2 (measured in serum via immunoassay) have been shown to be iuCTeased in human patients with inflammatory bowel disease (Vestergaard et al., 2004 Aamann et al., 2014). 

4 Diamine Oxidase Diamine oxidase (DAO, his-taminase) is a degradative enzyme of the polyamine metabolic pathway that is expressed in mature epithelium lining the rodent intestinal villi (Luk et al., 1980). Diminished blood concentrations, measurable by tritiated water assay, have been shown to correlate well with tissue expression 

---