title: DNA damage in lens epithelium of cataract patients in vivo and ex vivo.
abstract: OBJECTIVE
  DNA damage has been described in the human cataractous lens epithelium, and oxidative stress generated by UV radiation and endogenous metabolic processes has been suggested to play a significant role in the pathogenesis of cataract. In this study, the aim was to explore the quality and relative quantity of DNA damage in lens epithelium of cataract patients in vivo and after incubation in a cell culture system.
  
  
  METHODS
  Capsulotomy specimens were analysed, before and after 1 week of ex vivo cultivation, using the comet assay to measure DNA strand breaks, oxidized purine and pyrimidine bases and UV-induced cyclobutane pyrimidine dimers.
  
  
  RESULTS
  DNA strand breaks were barely detectable, oxidized pyrimidines and pyrimidine dimers were present at low levels, whereas there was a relatively high level of oxidized purines, which further increased after cultivation.
  
  
  CONCLUSIONS
  The observed levels of oxidized purines in cataractous lens epithelium may support a theory consistent with light damage and oxidative stress as mediators of molecular damage to the human lens epithelium. Damage commonly associated with UV-B irradiation was relatively low. The levels of oxidized purines increased further in a commonly used culture system. This is of interest considering the importance and versatility of ex vivo systems in studies exploring the pathogenesis of cataract.
authors.affiliation: Department of Ophthalmology, Center for Eye Research, Oslo University Hospital, University of Oslo, Oslo, NorwayDepartment of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Oslo, NorwayDepartment of Pathology, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Oyvind
authors.initials: O
authors.lastname: Øsnes-Ringen
authors.forename: Amaia O
authors.initials: AO
authors.lastname: Azqueta
authors.forename: Morten C
authors.initials: MC
authors.lastname: Moe
authors.forename: Charlotta
authors.initials: C
authors.lastname: Zetterström
authors.forename: Magnus
authors.initials: M
authors.lastname: Røger
authors.forename: Bjørn
authors.initials: B
authors.lastname: Nicolaissen
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Collins
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000378:metabolism / Q000473:pathology*; D018929:Cell Culture Techniques; D020552:Comet Assay; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004848:Epithelium / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D007903:Lens Capsule, Crystalline / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D018918:Phacoemulsification; D011740:Pyrimidine Dimers / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D011740:Pyrimidine Dimers; C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA