Gastroenterology

Gastroenterology

Volume 137, Issue 4, October 2009, Pages 1425-1434
Gastroenterology

Basic—Alimentary Tract
Activation of Human Enteric Neurons by Supernatants of Colonic Biopsy Specimens From Patients With Irritable Bowel Syndrome

https://doi.org/10.1053/j.gastro.2009.07.005Get rights and content

Background & Aims

Pathological features in irritable bowel syndrome (IBS) include alterations in mucosal cell content and mediator release that might alter signaling to nearby submucosal neurons.

Methods

Voltage sensitive dye imaging was used to record the effects of mediators, released from mucosal biopsies of IBS patients, on cell bodies of 1207 submucosal neurons from 76 human colonic tissue specimens. Supernatants, containing these mediators, were collected following incubation with colonic mucosal biopsies from 7 patients with diarrhea-predominant IBS (D-IBS), 4 with constipation-predominant IBS (C-IBS), and 4 healthy controls. Serotonin, histamine and tryptase concentrations in supernatants and lamina propria mast cell density were determined.

Results

In contrast to controls, IBS supernatants significantly increased the rate of spike discharge in 58% of human submucosal neurons. Neurons that responded to IBS supernatant had a median spike frequency of 2.4 Hz compared to 0 Hz for control supernatants. Supernatants from C-IBS and D-IBS evoked similar spike discharge. The activation induced by IBS supernatants was inhibited by histamine receptor (H1-H3) antagonists, 5-HT3 receptor antagonist, and protease inhibition. Serotonin, histamine and tryptase levels in supernatants correlated with the spike discharge induced by the supernatants. Mast cells density as well as histamine and tryptase levels in supernatants were higher in IBS than in controls.

Conclusions

Mediators released from mucosal biopsies of IBS patients can activate human submucosal neurons. The activation required histamine, serotonin and proteases but was not associated with IBS subtype. Altered signaling between mucosa and the enteric nervous system might be involved in IBS pathogenesis.

Section snippets

Study Participants and Tissue Samples

Patients (n = 11; 7 diarrhea-predominant IBS [D-IBS], 4 with constipation-predominant IBS [C-IBS]; Table 1) were recruited in the Department of Internal Medicine and Gastroenterology of the University of Bologna and diagnosed according to the Rome II criteria.22 Biopsy samples were taken when the patients were symptomatic. Generally, patients were in their flare of symptoms, and colonoscopy was performed shortly after consultation. To evaluate the symptoms, each patient completed a modified

Results

Neuroimaging data were obtained from 76 surgical tissue specimens, 137 ganglia containing a total of 1207 neurons. There was no correlation between the number of neurons activated by the supernatants and the following parameters related to the patients operated on for colectomy: age (P = .068), gender (P = .910), diagnosis (P = .737), or colonic region of the surgical specimen (P = .223). In addition, neuronal activity evoked by the supernatants did not correlate with the age (P = .917) and

Discussion

The current study revealed 3 major results. First, mediators released from colonic mucosal biopsy samples of patients with IBS excited neurons of the human submucosal plexus. Second, the excitation was not related to IBS subtypes and may therefore represent a general feature in IBS. Third, IBS supernatant-evoked excitation was mediated by proteases, histamine, and serotonin, with proteases appearing to play a dominant role. Our results are consistent with the concept that an altered signaling

References (42)

  • J. Aerssens et al.

    Alterations in mucosal immunity identified in the colon of patients with irritable bowel syndrome

    Clin Gastroenterol Hepatol

    (2008)
  • T. Liebregts et al.

    Immune activation in patients with irritable bowel syndrome

    Gastroenterology

    (2007)
  • V.E. Barrios et al.

    Proteinase-activated receptor-2 mediates hyperresponsiveness in isolated guinea pig bronchi

    Biochem Pharmacol

    (2003)
  • A.M. Coelho et al.

    Proteinases and proteinase-activated receptor 2: a possible role to promote visceral hyperalgesia in rats

    Gastroenterology

    (2002)
  • A. Kassinen et al.

    The fecal microbiota of irritable bowel syndrome patients differs significantly from that of healthy subjects

    Gastroenterology

    (2007)
  • E.A. Smith et al.

    Studies on amine production in the human colon: enumeration of amine forming bacteria and physiological effects of carbohydrate and pH

    Anaerobe

    (1996)
  • N. Arebi et al.

    Review article: the psychoneuroimmunology of irritable bowel syndrome—an exploration of interactions between psychological, neurological and immunological observations

    Aliment Pharmacol Ther

    (2008)
  • F. Azpiroz et al.

    Mechanisms of hypersensitivity in IBS and functional disorders

    Neurogastroenterol Motil

    (2007)
  • M. Camilleri et al.

    Prospective study of motor, sensory, psychologic, and autonomic functions in patients with irritable bowel syndrome

    Clin Gastroenterol Hepatol

    (2008)
  • R. Spiller et al.

    Post-infectious irritable bowel syndrome

    Curr Opin Gastroenterol

    (2006)
  • J. Macsharry et al.

    Mucosal cytokine imbalance in irritable bowel syndrome

    Scand J Gastroenterol

    (2008)
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    Conflicts of interest The authors disclose no conflicts.

    Funding Supported by Deutsche Forschungsgemeinschaft DFG Sche-267/7-1 (to M.S.); European Union 7th Framework Programme (IPODD) (to M.S.); Italian Ministry of University and Research (COFIN Projects to G.B., R.D.G.), R.F.O. funds from the University of Bologna (to R.D.G., V.S., G.B.), and a grant from the “Fondazione Del Monte di Bologna e Ravenna” (Bologna, Italy; to R.D.G.).

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