[Distribution of fibronectin and laminin during development of the human myenteric plexus and Hirschsprung's disease].

The distribution of fibronectin and laminin, two glycoproteins involved in the migration of neural crest cells, was studied by an indirect immunohistofluorescence technique in 35 embryos and fetuses (from 6 weeks old to birth), 5 normal controls, and 6 patients with Hirschsprung's disease, in order to provide a new approach to the embryogenesis of human myenteric plexus and the pathogenesis of aganglionosis. Fibronectin was not seen near individual neuroblasts unlike myoblasts and mesenchymal cells which were surrounded by this macromolecule. There was a progressive and parallel cephalocaudal development of the plexus and the muscular layers from the esophagus to the intestine. However, in the rectum, at 7 weeks, neuroblasts were detected in close contact to fibronectin-labeled cells whereas they were not in the colon. These present results were in favor of two origins for neuroblasts: the vagal and the caudal neural crest cells. Faulty migration of caudal neural crest cells might be involved in the aganglionosis of Hirschsprung's disease in spite of the fact that local environment of fibronectin and laminin was identical to that of normal subjects.