title: Topographic and age-dependent expression of heme oxygenase-1 and catalase in the human retinal pigment epithelium.
abstract: OBJECTIVE
  To investigate the hypothesis that there are topographic and age-related changes in the expression of heme oxygenase (HO)-1 and catalase in the RPE.
  
  
  METHODS
  Cryosections of the macula and periphery of human eyes (n = 18; aged 27-87 years) were subjected to a high-sensitivity digoxigenin (DIG)-labeled cRNA in situ hybridization protocol to determine the expression of HO-1 and catalase. The immunoreactivity of HO-1 and catalase were also investigated in the same sample set. Specimens were examined by light microscopy, and images were captured with a digital camera. The total number of RPE cells and HO-1- and catalase-labeled RPE cells was counted in each section, and the ratio of labeled RPE cells to total RPE cells was calculated in both the macular and the peripheral regions of each donor eye.
  
  
  RESULTS
  There was a mosaic pattern of mRNA and protein expression of HO-1 and catalase in macular and peripheral RPE. Topographical differences in the expression of HO-1 at the mRNA level and catalase at both the mRNA and protein levels was also observed. The topographical differences between the expression of HO-1 in the macula and periphery protein were not statistically significant but showed similar trends. For HO-1, the only significant age-related decline in expression was observed in the macula and periphery. Expression of HO-1 at the protein level and that of catalase at both the mRNA and protein levels showed no significant decline with age.
  
  
  CONCLUSIONS
  There is a possible age-related decline in HO-1 expression, whereas catalase expression remains unchanged with aging. Both exhibit mosaic patterns in the RPE monolayer.
authors.affiliation: Department of Ophthalmology and Molecular and Cellular Biology, University of California, Davis, California, USA.
authors.forename: Noritake
authors.initials: N
authors.lastname: Miyamura
authors.forename: Tsukihiko
authors.initials: T
authors.lastname: Ogawa
authors.forename: Sharon
authors.initials: S
authors.lastname: Boylan
authors.forename: Lawrence S
authors.initials: LS
authors.lastname: Morse
authors.forename: James T
authors.initials: JT
authors.lastname: Handa
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Hjelmeland
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D002452:Cell Count; D005260:Female; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D010857:Pigment Epithelium of Eye / Q000201:enzymology*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D012333:RNA, Messenger; D002374:Catalase; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1