Morphometric aspects of the submucous plexus in whole-mount preparations of normal human distal colon

The diagnosis of intestinal neuronal dysplasia (IND) has traditionally been based on the finding of hyperplasia of the submucous plexus and increased acetylcholinesterase activity in parasympathetic nerve fibers in the lamina propria. However, recently it has been suggested that proposed diagnostic criteria relating to nerve cell density may overlap with age-related changes and that the finding of giant ganglia (ganglia containing more than seven ganglion cells) is the most relevant diagnostic parameter of IND. Ganglion cell counting is usually performed on conventional histological sections, whereas the topology of whole ganglia has been poorly studied. The aim of this study was to define the number of ganglion cells per ganglion and the ganglion cell density (the number of ganglion cells per surface area) in submucous whole-mount preparations of normal human colon.

Specimens from distal colon were obtained during postmortem examination from 14 patients who died of nongastrointestinal disease. The submucous layer was prepared as a whole mount and stained for NADPH diaphorase (a nitrergic neurotransmitter marker) and cuprolinic blue (a general neuronal marker). Ganglion cell density was estimated by counting at least 10 mm2. The number of ganglion cells per ganglion was counted in at least 20 ganglia per case.

Ganglion cell density (NADPH diaphorase) fell markedly during the first 5 to 6 years of life (r = -0.60, P < .05). Most ganglion cells formed ganglia of 3 to 64 cuprolinic blue staining cells. The mean number of ganglion cells per ganglion did not vary with age.

The density of NADPH diaphorase-positive ganglion cells in the submucous plexus of human distal colon decreases markedly with age. However, the number of ganglion cells per ganglion remains constant. These findings indicate that the age of the patient has crucial importance for the histolopathologic evaluation of enteric nervous system disorders.