title: HIV enteropathy: crypt stem and transit cell hyperproliferation induces villous atrophy in HIV/Microsporidia-infected jejunal mucosa.
abstract: OBJECTIVE
  The study aim was to analyse the kinetics of stem and transit cells in the crypts of jejunal mucosa infected with HIV and Microsporidia.
  
  
  METHODS
  The size of villi, depth of crypts and proliferative activity of transit and stem cells in jejunal mucosa were measured using morphometric techniques.
  
  
  METHODS
  The surface area/volume ratio (S/V) of jejunal biopsies was estimated under light microscopy using a Weibel graticule. Crypt length was measured by counting enterocytes along the crypt side from the base to the villus junction, and the mean crypt length was calculated. The S/V and crypt lengths of the jejunal mucosa of 21 HIV and Microsporidia-infected test cases were compared with 14 control cases. The labelling index in relation to the crypt cell position of 10 of the test cases was analysed compared with 13 control cases.
  
  
  RESULTS
  Differences were found in the S/V and crypt length, and there was a negative correlation between S/V and crypt length in test and control cases combined. Cell labelling indices fell into low and high proliferation groups. There were significant differences in labelling indices between low proliferation test cases and controls, between high proliferation test cases and controls, and between high and low proliferation test cases.
  
  
  CONCLUSIONS
  Villous atrophy induced by HIV and Microsporidia is attributed to crypt cell hyperplasia and the encroachment of crypt cells onto villi. These infections induce crypt hypertrophy by stimulating cell mitosis predominantly in transit cells but also in stem cells. Increased stem cell proliferation occurs only in high proliferation cases.
authors.affiliation: Department of Histopathology, Bradford Teaching Hospitals Foundation Trust, Bradford, UK. philip.batman@bradfordhospitals.nhs.uk
authors.forename: Philip A
authors.initials: PA
authors.lastname: Batman
authors.forename: Donald P
authors.initials: DP
authors.lastname: Kotler
authors.forename: Moses S
authors.initials: MS
authors.lastname: Kapembwa
authors.forename: Dawn
authors.initials: D
authors.lastname: Booth
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Potten
authors.forename: Jan M
authors.initials: JM
authors.lastname: Orenstein
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Scally
authors.forename: George E
authors.initials: GE
authors.lastname: Griffin
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000150:complications / Q000473:pathology*; D000328:Adult; D001284:Atrophy / Q000382:microbiology / Q000473:pathology; D001706:Biopsy; D002452:Cell Count; D049109:Cell Proliferation; D005260:Female; D019053:HIV Enteropathy / Q000150:complications / Q000473:pathology*; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology*; D007583:Jejunum / Q000473:pathology*; D008297:Male; D016881:Microsporidiosis / Q000150:complications / Q000473:pathology*; D008875:Middle Aged; D019879:Paneth Cells / Q000473:pathology; D013234:Stem Cells / Q000473:pathology