peptide-phi and Colitis--Ulcerative

The study was undertaken to examine regional differences in the concentrations of five regulatory peptides in the human colonic mucosa. Biopsies were obtained during routine colonoscopy from 33 patients whose colonic mucosa was macroscopically and histologically normal. Regulatory peptides were extracted, and measured by specific radioimmunoassays. Concentrations of three peptides that are present predominantly in endocrine cells within colonic mucosa increased significantly towards the rectum: Mean concentrations of peptide YY, enteroglucagon, and somatostatin were about three times greater in the rectum than in the cecum. However, concentrations of two peptides that are present in mucosal nerve fibers diminished significantly towards the rectum: Mean rectal concentrations of vasoactive intestinal peptide and peptide histidine methionine were both about 0.6 of mean cecal concentrations. Concentrations of all five peptides were lower in biopsies taken from colonic polyps than in normal colonic mucosa. Regional differences in colonic mucosal concentrations of regulatory peptides probably reflect differences in the physiological functions of different parts of the colon.

Topics: Adolescent; Adult; Aged; Cecum; Colitis, Ulcerative; Colon; Colonic Polyps; Crohn Disease; Female; Gastrointestinal Hormones; Glucagon-Like Peptides; Humans; Intestinal Mucosa; Male; Middle Aged; Peptide PHI; Peptide YY; Peptides; Radioimmunoassay; Rectum; Somatostatin; Vasoactive Intestinal Peptide

The sequence for peptide histidine-methionine is present within the same preprohormone as vasoactive intestinal polypeptide. Since our previous study using radioimmunoassay had demonstrated significantly decreased colonic concentrations of vasoactive intestinal polypeptide in ulcerative colitis and Crohn's colitis compared to normal colon, we determined the distribution and quantitation of peptide histidine-methionine. Fresh surgical specimens were dissected into mucosal-submucosal and muscularis externa layers prior to acid extraction and specific radioimmunoassay. One immunoreactive species that appeared to coelute with peptide histidine-methionine was separated by reverse-phase high-performance liquid chromatography. Mucosal-submucosal concentrations of peptide histidine-methionine were significantly decreased in ulcerative colitis and Crohn's colitis, compared to those in normal colon. In normal ileum and colon, linear correlation analysis showed no relationship between patient age and tissue concentrations of peptide histidine-methionine. However, a parallel decrease in molar concentrations of peptide histidine-methionine and vasoactive intestinal polypeptide in ulcerative colitis and Crohn's colitis was demonstrated by linear correlation analysis. These results are consistent with the hypothesis that peptide histidine-methionine and vasoactive intestinal polypeptide are colocalized within the same neural structures that have been altered in the idiopathic inflammatory bowel diseases.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Aging; Chromatography, High Pressure Liquid; Colitis, Ulcerative; Colon; Crohn Disease; Humans; Ileum; Intestinal Mucosa; Middle Aged; Peptide PHI; Radioimmunoassay; Vasoactive Intestinal Peptide