title: Altered tryptophan hydroxylase 2 expression in enteric serotonergic nerves in Hirschsprung's-associated enterocolitis.
abstract: OBJECTIVE
  To determine if expression of colonic tryptophan hydroxylase-2 (TPH2), a surrogate marker of neuronal 5-hydroxytryptamine, is altered in Hirschsprung's-associated enterocolitis.
  
  
  METHODS
  Entire resected colonic specimens were collected at the time of pull-through operation in children with Hirschsprung's disease (HSCR, n = 12). Five of these patients had a history of pre-operative Hirschsprung's-associated enterocolitis (HAEC). Controls were collected at colostomy closure in children with anorectal malformation (n = 10). The distribution of expression of TPH2 was evaluated using immunofluorescence and confocal microscopy. Protein expression of TPH2 was quantified using western blot analysis in the deep smooth muscle layers.
  
  
  RESULTS
  TPH2 was co-expressed in nitrergic and cholinergic ganglia in the myenteric and submucosal plexuses in ganglionic colon in HSCR and healthy controls. Co-expression was also seen in submucosal interstitial cells of Cajal and PDGFRα(+) cells. The density of TPH2 immuno-positive fibers decreased incrementally from ganglionic bowel to transition zone bowel to aganglionic bowel in the myenteric plexus. Expression of TPH2 was reduced in ganglionic bowel in those affected by pre-operative HAEC compared to those without HAEC and healthy controls. However, expression of TPH2 was similar or high compared to controls in the colons of children who had undergone diverting colostomy for medically refractory HAEC.
  
  
  CONCLUSIONS
  Altered TPH2 expression in colonic serotonergic nerves of patients with HSCR complicated by HAEC may contribute to intestinal secretory and motor disturbances, including recurrent HAEC.
authors.affiliation: David Coyle, John Gillick, Temple Street Children's University Hospital, Dublin 1, Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Coyle
authors.affiliation: David Coyle, John Gillick, Temple Street Children's University Hospital, Dublin 1, Ireland.
authors.forename: Justin M
authors.initials: JM
authors.lastname: Murphy
authors.affiliation: David Coyle, John Gillick, Temple Street Children's University Hospital, Dublin 1, Ireland.
authors.forename: Brian
authors.initials: B
authors.lastname: Doyle
authors.affiliation: David Coyle, John Gillick, Temple Street Children's University Hospital, Dublin 1, Ireland.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: O'Donnell
authors.affiliation: David Coyle, John Gillick, Temple Street Children's University Hospital, Dublin 1, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Gillick
authors.affiliation: David Coyle, John Gillick, Temple Street Children's University Hospital, Dublin 1, Ireland.
authors.forename: Prem
authors.initials: P
authors.lastname: Puri
mesh_terms: D000075369:Anoctamin-1; D015415:Biomarkers / Q000032:analysis; D015153:Blotting, Western; D016022:Case-Control Studies; D018118:Chloride Channels / Q000032:analysis; D003106:Colon / Q000294:innervation* / Q000473:pathology / Q000601:surgery; D017615:Enteric Nervous System / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D004760:Enterocolitis / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D005260:Female; D005455:Fluorescent Antibody Technique; D006627:Hirschsprung Disease / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D007223:Infant; D008297:Male; D018613:Microscopy, Confocal; D009363:Neoplasm Proteins / Q000032:analysis; D017479:Receptors, Platelet-Derived Growth Factor / Q000032:analysis; D059326:Serotonergic Neurons / Q000201:enzymology*; D014365:Tryptophan Hydroxylase / Q000032:analysis*
chemical_list: C476213:ANO1 protein, human; D000075369:Anoctamin-1; D015415:Biomarkers; D018118:Chloride Channels; D009363:Neoplasm Proteins; C494784:TPH2 protein, human; D014365:Tryptophan Hydroxylase; D017479:Receptors, Platelet-Derived Growth Factor
keywords: Enterocolitis; Ganglionic; Hirschsprung; Serotonin; Tryptophan hydroxylase 2