Morphometric quantification of normal submucous plexus in the distal rectum of adult healthy volunteers

OBJECTIVE: Inadequate morphometric characterization of the normal adult submucous plexus has precluded the diagnosis of colonic dysganglionoses associated with constipation, such as intestinal neuronal dysplasia type B (IND B). The internal submucous plexus (Meissner plexus) was morphometrically quantified in adult healthy volunteers. DESIGN: Open, prospective morphometric study in balanced groups of female and male volunteers. PARTICIPANTS: Thirty-seven adult healthy male and female volunteers with normal bowel function and no history of gastrointestinal disease. METHODS: Four jumbo rectal biopsies (3-5 mm3) were taken 5 and 10 cm above the pectinate line. Two expert gastrointestinal pathologists assessed biopsy sections after specific nerve cell staining for lactic dehydrogenase, nitric oxide synthase and acetylcholinesterase, mainly for characteristics of ganglia and nerve cells in the submucous plexus. RESULTS: No healthy individual demonstrated over 20% of submucosal ganglia as giant ganglia or more than four giant ganglia per 30 sections (the morphometric criteria for IND B). Single submucosal nerve cells and ganglion numbers halved between 10 and 5 cm above the pectinate line, but there were no age or gender differences. The biological variability of nerve cell and ganglion density in the submucous plexus was large. CONCLUSIONS: Healthy adults show less than 20% of submucosal ganglia as giant ganglia and no more than four giant ganglia per 30 rectal biopsy sections. There is therefore no overlap with the histomorphological criteria of IND B. These data therefore support the specificity of the previously defined criteria for IND B in adults.