vasoactive-intestinal-peptide and Colonic-Polyps

To examine the changes that occur in the immunohistochemistry of vasoconstrictor and vasodilator transmitters in nerves supplying early and advanced colorectal polyps.. We studied the perivascular innervation of submucosal arterioles of colorectal polyps (n = 18) and the innervation of the epithelial layer of polyps compared to normal controls (n=8), using immunohistochemical markers for the neurotransmitters; noradrenaline (NA) (marker used; tyrosine hydroxylase (TH)), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), substance P (SP), and calcitonin gene-related polypeptide (CGRP). (Advanced polyps; villous adenomas>1.5 cm, polyps with severe dysplasia or partial carcinoma).. In submucosal arterioles there was a progressive decrease from controls through early polyps to advanced polyps in TH and NPY perivascular immunoreactivity (P<0.015 for both). VIP and SP immunoreactivity was higher in early polyps compared to controls, but markedly reduced in advanced polyps (P<0.05 for VIP). Sparse CGRP immunoreactivity was present in polyps only. Neural VIP and SP immunoreactivity in the lamina propria of polyp mucosa was more intense than in controls.. There is a decrease in vasoconstrictor neurotransmitters NPY and NA (shown by TH) around submucosal arterioles of both early and advanced polyps, but an increase in the vasodilator neurotransmitters, particularly VIP, in early colorectal polyps. These results suggest a predominantly vasodilatory neural influence in early polyps, perhaps indicating a mechanism that maintains polyp growth.

Topics: Aged; Arterioles; Biomarkers, Tumor; Calcitonin Gene-Related Peptide; Colon; Colonic Polyps; Female; Humans; Immunohistochemistry; Male; Middle Aged; Neuropeptide Y; Norepinephrine; Substance P; Tyrosine 3-Monooxygenase; Vasoactive Intestinal Peptide

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