Neuropeptides in idiopathic chronic constipation (slow transit constipation)

Area of Science:

• Gastroenterology
• Neurogastroenterology
• Colorectal Research

Background:

• Slow transit constipation (STC) is a functional gastrointestinal disorder characterized by delayed colonic transit.
• The enteric nervous system (ENS) and its neuropeptides play a crucial role in regulating colonic motility.
• Alterations in neuropeptide and amine distribution may underlie the pathophysiology of STC.

Purpose of the Study:

• To investigate the distribution and density of neuropeptides and endocrine cells in the large bowel of patients with STC.
• To compare these findings with those of normal individuals.
• To identify potential neurochemical markers associated with STC.

Main Methods:

• Immunohistochemistry was used to study neuropeptides including CGRP, galanin, glucagon, GRP, metenkephalin, motilin, NPY, PACAP, PYY, serotonin, somatostatin, substance P, and VIP.
• Radioimmunoassay was employed to measure tissue concentrations of VIP, substance P, and galanin.
• Tissue specimens were obtained from 18 patients with STC and compared to normal controls.

Main Results:

• Significantly increased VIP, substance P (SP), and galanin levels were observed in the ascending colon of STC patients.
• Elevated VIP and galanin concentrations were also noted in the transverse colon.
• Increased PACAP nerve fibers in the transverse colon's myenteric plexus and smooth muscle, alongside increased PYY and serotonin (5-HT) cells in the ascending colon, were found.

Conclusions:

• STC is associated with significant alterations in the neurochemical composition of the colon.
• Specific neuropeptides like VIP, galanin, and substance P, as well as PYY and 5-HT, show altered distribution and density in STC patients.
• These neurochemical changes likely contribute to the impaired colonic motility observed in slow transit constipation.