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Open Access Research article

The association of mast cells and serotonin in children with chronic abdominal pain of unknown etiology

Tara J Taylor1, Nader N Youssef2, Ravi Shankar1, David E Kleiner3 and Wendy A Henderson1*

Author Affiliations

1 National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA

2 Center for Pediatric Functional Gastrointestinal and Motility Disorders, Goryeb Children's Hospital at Atlantic Health, University of Medicine & Dentistry of New Jersey, Morristown, NJ, USA

3 National Cancer Institute, National Institutes of Health, Bethesda, MD, USA

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BMC Research Notes 2010, 3:265  doi:10.1186/1756-0500-3-265

Published: 21 October 2010

Abstract

Background

Abdominal pain of unknown origin affects up to 20% of school-aged children. Evaluation of children is symptom-based without clear guidelines to investigate molecular mechanisms of abdominal pain. Aberrant molecular mechanisms may increase intestinal permeability leading to interactions between the immune and nervous systems, subclinical inflammation, and visceral pain. This study evaluated the association between interleukin-6 (IL-6), mast cell infiltrates, and serotonin (5-HT) levels in gastrointestinal (GI) biopsies, with perceived abdominal pain in a pediatric cohort.

Methods

Clinical data and biopsy samples from pediatric patients (n = 48) with chronic abdominal pain, with and without inflammation were included. Formalin-fixed paraffin-embedded GI biopsies were sectioned and immunohistochemistry performed for IL-6 and 5-HT; mast cells were identified with toluidine blue stain. Histological findings were compared to self-reported abdominal pain between groups.

Results

There was significantly greater IL-6 immunoreactivity in biopsies with confirmed histologic inflammation (p = 0.004). There was a greater number of mast cells per HPF in non-inflammatory biopsies (3.5 ± 2.9) compared to the inflammatory biopsies (2.6 ± 1.8) p = 0.049. The non-inflammatory biopsy group was significantly less likely to respond to standard treatment as evidenced by higher pain reports (p = .018). Mast cells (p = .022) and 5-HT (p = .02) were significantly related to abdominal pain scores.

Conclusions

A potential association between self-reported abdominal pain, number of mast cells, and 5-HT levels, which may contribute to perceived GI pain in pediatric patients may exist.