Hirschsprung's disease--immunohistochemical findings

Area of Science:

• Gastroenterology
• Neuroscience
• Developmental Biology

Background:

• Hirschsprung's disease (HSCR), or aganglionosis coli, results in intestinal obstruction due to absent nerve ganglia in the distal colon.
• Impaired intestinal peristalsis in HSCR is linked to deficient non-adrenergic, non-cholinergic (NANC) inhibitory innervation and smooth muscle relaxation.

Purpose of the Study:

• To characterize the disturbed NANC innervation in Hirschsprung's disease using morphological and immunohistochemical methods.
• To investigate the presence and distribution of various neuropeptides and neuronal markers in the aganglionic intestinal segments of HSCR patients.

Main Methods:

• Conventional microscopy, immunohistochemistry, and immunochemistry were employed to analyze nerve fiber distribution.
• Specific antibodies were used to detect general neuronal markers (e.g., chromogranins) and neuropeptides (e.g., VIP, PACAP, NPY, CGRP, SP, enkephalins, galanin).
• The expression of nitric oxide synthase (NOS), an enzyme crucial for NANC inhibition, was also assessed.

Main Results:

• Aganglionic segments in HSCR showed reduced numbers of nerve fibers immunoreactive for VIP, PACAP, GRP, CGRP, SP, enkephalins, and galanin.
• Conversely, neuropeptide Y (NPY)-containing nerve fibers were increased, suggesting adrenergic hyperinnervation.
• Nitric oxide synthase (NOS) was found to be significantly reduced or absent in the neuronal system of the aganglionic intestine.

Conclusions:

• HSCR is characterized by a significant deficit in inhibitory NANC innervation, particularly involving nitric oxide.
• The observed alterations in neuropeptide and adrenergic innervation contribute to the functional obstruction seen in Hirschsprung's disease.
• These findings highlight the complex neurochemical changes underlying HSCR and suggest potential targets for therapeutic strategies.