title: Chronic low-dose aspirin use does not alter colonic mucosa in asymptomatic individuals: a prospective cross-sectional study (STROBE 1a).
abstract: OBJECTIVE
  Aspirin may be involved in microscopic colitis (MC) development, but there are no data on colon histology in asymptomatic aspirin users. We prospectively assessed colonic and rectal mucosa from aspirin users, searching for MC features.
  
  
  METHODS
  From colonoscopy screenees, two biopsy samples were taken from each of three locations: ascending colon, transverse colon and rectum. A pathologist measured chronicity of inflammation and activity indicators, epithelial cell height and subepithelial collagen layer width. Intraepithelial lymphocytes (IELs), intralaminal eosinophils and apoptotic cells/100 crypts were counted. Panel data models were used to analyse associations between aspirin use, biopsy location and microscopic parameters.
  
  
  RESULTS
  Of 100 screenees (age: 40-65 years), 42 were current aspirin users. Median duration of aspirin usage was 48 months (range: 36-60) with dosage ranging from 75-325 mg/day. We observed reduced epithelium polymorphs in subjects who used aspirin for <48 months versus non-users (p=0.008). Paneth cell metaplasia was significantly less frequent in aspirin users versus non-users (p=0.006). Inflammatory cells in lamina propria (eosinophils) and epithelium (IELs) were most abundant in the ascending colon and decreased distally (ascending colon vs transverse colon and transverse colon vs rectum). Cryptitis was more frequent in the ascending colon vs the rectum.
  
  
  CONCLUSIONS
  We observed no specific MC features in asymptomatic chronic low-dose aspirin users. We found subtle physiological and histopathological differences between the bowel segments.
authors.affiliation: Department of Gastroenterology and Hepatology, Medical Center for Postgraduate Education and The Maria Sklodowska-Curie Memorial Cancer Centre and Institute of Oncology, , Warsaw, Poland.
authors.forename: Edyta
authors.initials: E
authors.lastname: Zagorowicz
authors.forename: Andrzej
authors.initials: A
authors.lastname: Mroz
authors.forename: Ewa
authors.initials: E
authors.lastname: Kraszewska
authors.forename: Maciej
authors.initials: M
authors.lastname: Rupinski
authors.forename: Michal F
authors.initials: MF
authors.lastname: Kaminski
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Regula
mesh_terms: D000328:Adult; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D001241:Aspirin / Q000009:adverse effects*; D003113:Colonoscopy; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin
keywords: Collagenous Colitis; Colon; Histopathology; Inflammation