BSPGHAN 2021 Virtual Annual Meeting

27- 29 April 2021

Sean Devane Prize- Best Gastroenterology Presentation

Oesophageal Mucosa Innervation in Paediatric Eosinophilic Oesophagitis

Kornilia Nikaki, Ahsen Ustaoglu, Chung Lee, Philip Woodland and Daniel Sifrim. 

Wingate Institute of Neurogastroenterology, Blizard Institute, QMUL

Introduction: 
The mechanism for symptom generation in eosinophilic oesophagitis (EoE) is not completely clear. Together with mechanical obstruction due to decreased oesophageal wall distensibility, oesophageal hypersensitivity has been noted. Hypersensitivity can be due to impairment of mucosal integrity and/or sensitization of mucosal nerves. The aim of our study was to delineate the mucosal innervation in the proximal and distal oesophagus in paediatric EoE and control subjects and correlate this with the histological findings. 

Methods: 
We prospectively recruited children undergoing an upper GI endoscopy for clinical reasons and identified a subgroup with normal histology +/- normal impedance pH-metry that served as controls and a patient group with histologically confirmed EoE. We obtained oesophageal biopsies from 3-5cm above the lower oesophageal sphincter and from the proximal/upper third. The biopsies were immunohistochemically stained for CGRP and TRPV1. CGRP positive nerve fibres were identified and their position relative to the lumen was determined (expressed as median number of cell layers from the lumen for all sections examined). The peak eosinophilic count per high power field (HPF) was used as proxy of disease activity in EoE. 

Results: 
Nineteen children were included in the control group (12M:7F, median age: 11 years) and 12 in the EoE group (9M:2F, median age: 12 years). In the control group, CGRP positive nerve fibres were identified at a median of 19.5 cell layers from the lumen in the proximal and 19 cell layers in the distal oesophagus (Image 1). In the EoE group, CGRP positive nerve fibres were identified at a median of 14 cell layers in the proximal and 12.6 cell layers in the distal oesophagus (p=0.0009 and 0.01 respectively). There is a weak correlation between the number of eosinophils per HPF and the position of the nerve fibres in the oesophageal mucosa (r=-0.46). None of the nerve fibres identified expressed the TRPV1 receptor. 

Conclusion: 
The oesophageal mucosa innervation in children with EoE is similar in the proximal and distal oesophagus with more superficial lying nerve fibres compared to controls. The superficiality of the nerve fibres may be driven by the underlying inflammation. These findings may contribute to the oesophageal hypersensitivity noted in EoE despite histological remission.