title: Cell death pattern in lens epithelium of cataract patients.
abstract: OBJECTIVE
  Apoptosis, a type of programmed cell death, is observed in various types of cataract and in cultured lens epithelium subjected to oxidative damage. We have recently described oxidative DNA base damage in epithelium in age-related cataract and cultured cells, and we here aimed to examine such epithelium for markers for proliferation, initiation of apoptosis and morphological patterns of cell damage.
  
  
  METHODS
  Samples (n = 75) were analysed by light microscopy/electron microscopy (LM/EM); immunohistochemistry (IHC) for PCNA and Ki67 (DNA synthesis/proliferation); TUNEL assay (DNA fragmentation/apoptosis); and protein/gene expression of Caspase-3 (apoptotic effector molecule) and BAX/Bcl2 (pro-/anti-apoptotic marker) in fresh/cultured epithelium by IHC and qRT-PCR.
  
  
  RESULTS
  In fresh samples, the majority of cells were Ki67-/PCNA+. BAX/BCL-2-ratio was approximately 1, and Caspase-3 levels were low. TUNEL stained scattered nuclei/nuclear fragments (9/6302 cells). Main morphological signs of cell damage included rupture of cell membranes and hydration of cytoplasm and nuclei. Cultivation increased levels of BAX and Bcl2 by IHC and qRT-PCR (approximately 10-fold upregulation). Caspase-3 levels remained low by IHC with similar expression in fresh and cultured samples by qRT-PCR.
  
  
  CONCLUSIONS
  Genomic stress and DNA repair may explain the contrasting expression of Ki67/PCNA in fresh epithelium. Despite low levels of Caspase-3 and similar expression of BAX/Bcl-2, a low incidence of apoptosis may be detected in epithelium in age-related corticonuclear cataract. Epithelium may be transferred to culture without an increase in expression of Caspase-3, one of the central mediators of apoptosis.
authors.affiliation: Center for Eye Research, Department of Ophthalmology, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Osnes-Ringen
authors.affiliation: Center for Eye Research, Department of Ophthalmology, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Kristiane Haug
authors.initials: KH
authors.lastname: Berg
authors.affiliation: Center for Eye Research, Department of Ophthalmology, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Morten C
authors.initials: MC
authors.lastname: Moe
authors.affiliation: Center for Eye Research, Department of Ophthalmology, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Charlotta
authors.initials: C
authors.lastname: Zetterström
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.
authors.forename: Magnus
authors.initials: M
authors.lastname: Røger
authors.affiliation: Center for Eye Research, Department of Ophthalmology, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Bjørn
authors.initials: B
authors.lastname: Nicolaissen
mesh_terms: D017209:Apoptosis; D015415:Biomarkers / Q000378:metabolism; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D002386:Cataract / Q000378:metabolism / Q000473:pathology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D053938:DNA Fragmentation; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000378:metabolism; D007903:Lens Capsule, Crystalline / Q000378:metabolism / Q000473:pathology*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008858:Microscopy, Phase-Contrast; D016133:Polymerase Chain Reaction; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C494826:BAX protein, human; C000595707:BCL2 protein, human; D015415:Biomarkers; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D053148:Caspase 3
keywords: Bax; Bcl-2; Caspase-3; TUNEL; apoptosis; cataract; human; lens; lens epithelium