Universal distribution of c-kit-positive cells in different types of Hirschsprung's disease

Interstitial cells of Cajal (ICCs) have been reported to play the role of a pacemaker in regulating bowel motility. The relationship between neurons and ICCs, however, remains unclear. Hirschsprung's disease (HD) is an ideal model for investigating this relationship. The operated specimens obtained from 6 short and 3 long segment aganglionosis patients and 3 controls were used as the subject materials in this study. ICCs were immunohistochemically identified using a specific antiserum c-kit, a tyrosine kinase receptor expressing ICCs. Nitrergic nerves were demonstrated by NADPH-diaphorase (NADPH-d) histochemistry. C-kit immunohistochemistry was also combined with protein gene product 9.5 (PGP 9.5; as a general neuronal marker). In the normoganglionic segment of HD, numerous c-kit-positive cells and NADPH-d positive neurons were found in the proper muscle layer, including Auerbach's plexus. In the oligoganglionic segment, the number of c-kit-positive cells and NADPH-d neurons slightly decreased. In the inner border of the circular muscle layer (IBCM), the c-kit-positive cell networks and NADPH-d activities remained in short segment cases, while both of them were absent in the long segment cases. In the aganglionic segment, c-kit positive cells were present universally but the number of them was slightly decreased in the proper muscle layer. The c-kit-positive cell networks of IBCM were seen where extrinsic neurons were present, while they were almost completely absent where extrinsic neurons were absent in the proximal zone of the long segment cases. C-kit positive cells were present universally in the oligoganglionic as well as aganglionic segments of HD. The distribution and properties of c-kit positive cells were related to the presence of extrinsic neurons in aganglionic segment. Based on these findings, aperistalsis is considered not to relate with c-kit positive cells, and c-kit positive cells are not supposed to have a neurogenic origin and can develop without neurons, however the lack of enteric neurons may influence the full differentiation of ICCs.