title: Lysozyme is up-regulated in columnar-lined Barrett's mucosa: a possible natural defence mechanism against Barrett's esophagus-associated pathogenic bacteria.
abstract: BACKGROUND
  Lysozyme is a natural antimicrobial enzyme that is up-regulated in inflammatory diseases of the gastrointestinal tract. Pathogenic microbes have recently been identified in the esophageal mucosa in patients with Barrett's esophagus (BE). Lysozyme expression was evaluated in biopsies from patients with BE.
  
  
  METHODS
  Ninety-seven consecutive esophageal biopsies with columnar-lined Barrett's mucosa (BM) were investigated: 16 had oxyntic gland-only BM, 19 pyloric gland-only BM and 62, intestinal metaplasia BM. Twenty normal gastric biopsies and 20 normal duodenal biopsies were included as controls. Sections were stained with human lysozyme antiserum.
  
  
  RESULTS
  Lysozyme was up-regulated in the neck glands in 94% of the biopsies with oxyntic gland-only BM, in the pyloric gland in 79% of the biopsies with pyloric gland-only BM, and in goblet cells in 65% of the biopsies with intestinal metaplasia BM. Goblet cells with faint lysozyme expression were often found in glands overexpressing lysozyme in mucous secretions in the lumen. When compared to controls, lysozyme was up-regulated in all three BM phenotypes (p<0.05).
  
  
  CONCLUSIONS
  Lysozyme is up-regulated in BM. It is therefore, believed that lysozyme's up-regulation might mirror a molecular mechanism of self-defence aimed to safeguard the BM against the hostile pathogenic microbiota present in the esophageal microenvironment in patients with BE.
authors.affiliation: Gastrointestinal and Liver Pathology Research Laboratory, Department of Pathology, Karolinska Institute and University Hospital, 17176, Stockholm, Sweden. Carlos.Rubio@ki.se
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Rubio
mesh_terms: D001419:Bacteria / Q000378:metabolism* / Q000472:pathogenicity; D001471:Barrett Esophagus / Q000201:enzymology* / Q000382:microbiology* / Q000473:pathology; D001706:Biopsy; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007150:Immunohistochemistry; D009113:Muramidase / Q000032:analysis / Q000096:biosynthesis*; D015854:Up-Regulation
chemical_list: D009113:Muramidase