Editorial: the diminishing returns of normalisation of the oesophageal mucosa

Abstract

hampered by the lack of correlation between symptom improvement and changes in physiologic measures such as gastric emptying studies.A new direction in functional dyspepsia is the concept that the duodenum may be the source of symptoms. Observational studies show an increased number of eosinophils in duodenal biopsies obtained from adults and children with functional dyspepsia. [2][3][4] Other studies have shown an increase in mast cells in the mucosa and evidence of inflammation in the sub-mucosal nerves and ganglia in the upper gastrointestinal tract. 5An inflammatory reaction may trigger the accumulation of eosinophils in the duodenal mucosa. The trigger may be intrinsic through the brain-gut axis or extrinsic through ingested proteins or bacteria.During the inflammatory process, a number of cytokines are released and activate the eosinophils, which are then ready for degranulation.During the process of degranulation, nerve growth factor is released and may have an effect on the sensory nerves of the upper gastrointestinal tract. Other products of degranulation such as major basic proteins can affect smooth muscle function causing spasm. Studies have shown that children with atopy have duodenal eosinophilia and that challenge with cow's milk protein can generate dyspeptic symptoms. 6 Other studies have shown that inflammation, including eosinophilia, may be seen in patients with Helicobacter pylori infection. 7 The process by which extrinsic factors create duodenal eosinophilic infiltration is uncertain. One plausible postulate is that alterations in mucosal permeability allow food-based antigens and bacterial products exposure to the immune system. What are the implications for future treatments? Anti-inflammatory agents and drugs aimed at decreasing allergic reactions are already being studied in functional dyspepsia. 9,10 Observational studies, while confirming the original observation of duodenal eosinophilia, need to give way to mechanistic studies that help us understand the pathogenesis of duodenal eosinophilia. Future studies will help determine if treating the eosinophilia, much as we treat eosinophilic oesophagitis, or restricting the diet will alleviate dyspeptic symptoms. ACKNOWLEDGEMENTDeclaration of personal interests: Consultant Ironwood Pharmaceuticals.

Editorial: the diminishing returns of normalisation of the oesophageal mucosa―Authors' reply

“…We have read with great interest the editorial by Dr. Genta—an attempt to reconcile the short turnover time of the oesophageal squamous epithelium with the results of our study, which showed that complete “normalisation” of oesophageal histology takes at least a few years . The results obtained in the LOTUS study demonstrated that progressive improvement of oesophageal histology occurs over the course of 5 years, and the same phenomenon is observed with regard to the degree of epithelial proliferation assessed by Ki67.…”