title: Age- and site-dependent cell cycle composition of the normal human colonic mucosa.
abstract: OBJECTIVE
  As a reference to studies of DNA-ploidy and S- and G2/M-phase fractions in patients with inflammatory bowel diseases, we describe the mucosa of normal individuals with respect to age and localization in the colon.
  
  
  METHODS
  One hundred and sixty-five biopsies from the right, transverse and left colon from 44 subjects (20 men, 24 females, median age 55 years (range 21-80)) who were referred for colonoscopy due to rectal bleeding, diarrhoea or suspicion of neoplasia, but with normal macroscopic and microscopic findings, were analysed by DNA-flow cytometry for ploidy and cell cycle composition. The biopsies were immediately fixed in buffered formalin and then analysed by a method for high quality preparations of cell nuclei without any centrifugation steps, resulting in minimal cell damage and low frequencies of aggregates, making the background levels low in the DNA-histograms.
  
  
  RESULTS
  The median S-phase fraction of the biopsies, all diploid, was 2.35% (0.1-8.3). The S-phase fraction increased linearly with age (p = 0.001) and decreased from the right colon (median 2.75% (0.5-8.3)) over the transverse colon (median 2.3% (0.1-6.2)) to the left colon (median 1.9% (0.8-6.5), p < 0.02). The fraction of G2-cells (median 1.1%, range 0.2-5.1) increased significantly with increased S-phase fraction (p < 0.0001).
  
  
  CONCLUSIONS
  DNA-FCM analyses of normal colonic tissue demonstrate an age- and site-dependent variation with regard to cell proliferation. This variation has to be taken into consideration when biopsy specimens from chronic colitis mucosa are evaluated.
authors.affiliation: Department of Medicine, GE-Unit, Stockholm Söder Hospital, SE-118 83 Stockholm, Sweden. urban.sjoqvist@sos.sll.se
authors.forename: U
authors.initials: U
authors.lastname: Sjöqvist
authors.forename: R
authors.initials: R
authors.lastname: Löfberg
authors.forename: A
authors.initials: A
authors.lastname: Ost
authors.forename: B
authors.initials: B
authors.lastname: Tribukait
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002453:Cell Cycle / Q000502:physiology; D002455:Cell Division; D003106:Colon / Q000166:cytology* / Q000502:physiology; D004247:DNA / Q000235:genetics; D004171:Diploidy; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D012016:Reference Values
chemical_list: D004247:DNA