Suitability of selected markers for identification of elements of the Intestinal Nervous System (INS)

The possibility of identifying and characterising elements of the enteric nervous system based on their contents of cathepsin D, chromogranin A, neuronal specific enolase and S-100 protein was studied in colorectal specimens (operative full-thickness, seromuscular and mucosomuscular biopsies) obtained from 15 children, aged 2 days to 10 years. Nine patients suffered from Hirschsprung's disease, and two from chronic constipation. Four neonates with imperforate anus or meconium ileus composed the control group. All markers were identified immunohistochemically by antibodies against human antigens with appropriate detection methods. Chromogranin A staining was not always adequate to identify all neuronal cell bodies and other nervous elements. However, it proved superior to the other methods in the depiction of neuroendocrine cells in the intestinal mucosa. Cathepsin D antibodies stained normal and abnormal neural cells with different intensity; nerve fibres were not stained. This marker did not allow an unequivocal differentiation of ganglion cells from macrophages within the submucosa; the latter exhibited exceptionally strong marking and in some cases represented the predominant elements in this area. Neuronal specific enolase was distinctly expressed in nerve cells and fibres of the intestinal wall. Atrophic and hypoplastic features could be identified, suggesting that this method may give some insight into functional aspects. Continuous connections between ganglions were also observed. S-100 protein antibodies resulted in a negative image of unstained ganglion cells surrounded by extensively marked Schwann cells and neural fibres. With respect to clinical application, all these markers may provide supplementary information for the differential diagnosis of intestinal motility disorders.