Distribution and localization of glia fibrillary acidic protein in colons affected by Hirschsprung's disease

The distribution and localization of glial fibrillary acidic (GFA) protein were examined by means of immunohistochemistry in normoganglionic, oligoganglinonic, and aganglionic segments of colons from 25 patients with Hirschsprung's disease, including four cases of long segment aganglionosis. In normoganglionic segments, GFA proteinpositive glial cells were densely distributed within the myenteric plexus, but sparse in the submucous plexus. Aganglionic segments were completely devoid of glial cells with GFA protein immunoreactivity, coinciding with the lack of enteric ganglia. Instead, GFA protein was found specifically in association with the hypertrophic nerve fasciculi and their branches, which were mainly located in the intermuscular zone and submucosal connective tissue in the distal aganglionic segment of diseased bowels. However, two types of short and long segment aganglionosis differed in the distribution pattern of GFA protein; the extrinsic nerve fasciculi in short segment disease extended toward the normoganglionic segment, but in long segment disease they did not reach this area. A moderate number of GFA protein-positive fasciculi were observed within the circular muscle layer of proximal aganglionosis, while no immunoreactive fasciculi were encountered within the circular muscle layer of the corresponding parts in long segment aganglionosis. Immunohistochemistry for GFA protein can be of excellent diagnostic value for the aganglionic colon with Hirschsprung's disease, since GFA protein immunohistochemistry discloses exclusively extrinsic, hypertrophic nerve fasciculi, characteristic of the bowel in cases of Hirschsprung's disease.