piperidines and Hirschsprung-Disease

The aganglionosis in a variable length of the distal gut found in Hirschsprung's disease results from the abnormal prenatal development of neural crest-derived stem cells of the enteric nervous system. The cytokine endothelin-3 is necessary for successful colonization of the distal gut, but the location of this interaction with neural crest-derived stem cells remains to be established. The hypothesis tested here is that the stem cells of the enteric nervous system (ENS) in the colon are located at the leading edge of the migrating wave of neural crest-derived stem cells and that these cells require colonic endothelin-3 for complete colonization of the gut.. Explants of 11.5-day-old embryonic intact mouse gut and isolated colon were cultured for 72 hours in the presence and absence of the endothelin-B receptor antagonist, BQ788. Specimens then were sectioned and stained by immunohistochemistry to assess enteric nervous system development.. Isolated colon contained a very low number (mean, 73 cells; range, 37 to 106; n = 8) of neural crest-derived stem cells, which had just entered its proximal end at the leading edge of neural crest cell migration. After 72 hours of culture, progeny of these few neural crest-derived stem cells had colonized the colon at an equivalent ganglionic density to those in intact gut. Furthermore, neuronal differentiation, as shown by the appearance of nitric oxide synthase positive neurons, also was equivalent to intact gut. Blockade of the endothelin-B receptor produced terminal aganglionosis in both isolated colons and intact gut.. The very small number of cells that first enter the proximal colon at the leading edge of neural crest cell migration have the ability to colonize the entire colon normally in an ET-3-dependent manner. These cells therefore have the functional characteristics expected of the stem cells of the colonic enteric nervous system. Furthermore, the normal development of these cells is dependent on the endothelin-3 expressed by the mesenchymal cells of the colon itself.

Topics: Animals; Cell Movement; Cells, Cultured; Colon; Disease Models, Animal; Endothelin-3; Enteric Nervous System; Hirschsprung Disease; Mice; Neural Crest; Oligopeptides; Piperidines; Stem Cells

Hirschsprung's disease is associated with defects in the endothelin-3 and endothelin B receptor genes.. To assess the in vivo vasomotor responses to endothelin B receptor stimulation in patients with Hirschsprung's disease.. Forearm blood flow was measured using venous occlusion plethysmography in 10 patients with Hirschsprung's disease and 10 matched healthy controls during intra-brachial infusion of the highly selective endothelin B receptor agonist, sarafotoxin S6c. To simulate endothelin B receptor dysfunction, sarafotoxin S6c was co-infused with the highly selective endothelin B receptor antagonist, BQ-788, in six of the healthy controls.. Sarafotoxin S6c caused a brief initial vasodilatation followed by a slow-onset, sustained vasoconstriction (p<0.001). Compared to control subjects, patients with Hirschsprung's disease had a substantial impairment of the initial vasodilatation whilst producing a more pronounced subsequent vasoconstriction (p<0.001). In healthy controls, co-infusion of BQ-788 and sarafotoxin S6c caused a similar pattern of responses to those obtained in patients with Hirschsprung's disease: abolition of the initial vasodilatation and augmentation of subsequent vasoconstriction (p<0.001).. In the majority of patients with Hirschsprung's disease, there is a functional defect of the vascular endothelin B receptor.

Topics: Adult; Endothelin Receptor Antagonists; Female; Forearm; Hirschsprung Disease; Humans; Male; Oligopeptides; Piperidines; Receptor, Endothelin B; Receptors, Endothelin; Regional Blood Flow; Vasoconstrictor Agents; Vasomotor System; Viper Venoms

Terminal colonic aganglionosis (Hirschsprung disease) results from incomplete rostrocaudal colonisation of the embryonic gut by neural crest cells (NCC). Mutations in the genes encoding endothelin-3 (EDN3) or its receptor (EDNRB) have been shown to result in a similar aganglionosis. This article describes the development of an organ culture model using embryonic murine gut to determine how endothelin-3 regulates development of the enteric nervous system.. Gut explants from mice of different gestational ages were cultured for up to 3 days in the presence or absence of 5 micromol/L of the specific endothelin-B receptor antagonist BQ788. EDN3 and EDNRB mRNA expression were analysed by reverse-transcription polymerase chain reaction (RT-PCR) and whole-mount in situ hybridisation. NCC were localised using immunoreactivity for PGP 9.5, a specific neuronal marker.. EDN3 mRNA continued to be expressed by caecal mesenchymal cells and EDNRB mRNA by the migrating NCC in culture. Embryonic day (E)11.5 explants were already colonised by NCC up to the terminal ileum. Complete colonisation occurred in organ culture over the next 72 hours (equivalent to E 14.5). Explants of E 12.5 and E 13.5 showed complete colonisation after 48 and 24 hours culture, respectively. Terminal aganglionosis resulted from treatment of E 11.5 and E 12.5 gut explants with 5 micromol/L BQ788, whereas there was no inhibitory effect on E 13.5 explants.. An organ culture model has been developed in which NCC colonisation of embryonic gut mirrors that described in vivo. Blockade of the EDN3/EDNRB receptor pathway shows that the interaction of endothelin-3 with its receptor is only necessary for NCC colonisation at early time-points, despite the continued expression of endothelin-3 mRNA in the gut.

Topics: Animals; Cell Movement; Digestive System; Endothelin Receptor Antagonists; Endothelin-3; Enteric Nervous System; Hirschsprung Disease; Immunohistochemistry; In Situ Hybridization; Mice; Mice, Inbred Strains; Neural Crest; Oligopeptides; Organ Culture Techniques; Piperidines; Receptor, Endothelin B; Receptors, Endothelin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors

Topics: Cisapride; Colonic Diseases; Combined Modality Therapy; Hirschsprung Disease; Humans; Ileostomy; Infant; Intestinal Pseudo-Obstruction; Parenteral Nutrition, Total; Piperidines