title: Age-related histomorphologic changes in the canine gastrointestinal tract: a histologic and immunohistologic study.
abstract: OBJECTIVE
  To examine the changes in the histomorphology of the gastric, jejunal and colonic wall of dogs due to physiological aging.
  
  
  METHODS
  Full thickness biopsies were taken from the gastrointestinal tracts of 28 dogs of different ages. The thickness of the different layers of the wall was measured and the numbers of proliferating cells as indicated by immunohistochemical detection of Ki67 were counted.
  
  
  RESULTS
  In the three excision sites, the thickness of all subepithelial layers increased with rising age. The strongest correlation between age and thickness of the intestinal wall was found in the first 10 years of life and in the jejunum (r = 0.6-0.71 for the deep lamina propria mucosa, the muscularis mucosa, and the circular layer of the tunica muscularis). The number of proliferating cells decreased during aging, with the strongest correlation in the lamina propria mucosa and lamina muscularis mucosa of the jejunum and in the colonic submucosa (r = -0.61 to -0.71). Epithelial proliferation was only weakly correlated to the age.
  
  
  CONCLUSIONS
  The morphology of the deeper layers and the proliferation of mesenchymal cells of the intestinal wall of healthy dogs are correlated with age. Gastrointestinal epithelial proliferation is only weakly age-correlated.
authors.affiliation: Department of Pathology, University of Veterinary Medicine, Buenteweg 17, Hannover D-30559, Germany.
authors.forename: Berit
authors.initials: B
authors.lastname: Baum
authors.forename: Felix
authors.initials: F
authors.lastname: Meneses
authors.forename: Sven
authors.initials: S
authors.lastname: Kleinschmidt
authors.forename: Ingo
authors.initials: I
authors.lastname: Nolte
authors.forename: Marion
authors.initials: M
authors.lastname: Hewicker-Trautwein
mesh_terms: D000375:Aging / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D001706:Biopsy; D049109:Cell Proliferation; D003106:Colon / Q000378:metabolism / Q000473:pathology; D004285:Dogs; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000473:pathology*; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology*; D007583:Jejunum / Q000378:metabolism / Q000473:pathology; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D013270:Stomach / Q000473:pathology
chemical_list: D019394:Ki-67 Antigen