title: Mitochondrial abnormalities in ageing macular photoreceptors.
abstract: OBJECTIVE
  To evaluate somatic mitochondrial (mt)DNA mutations in the macula during ageing.
  
  
  METHODS
  Ten 30-microm cryostat sections from the macula (foveal and perifoveal regions) and peripheral retina of 14 donors (aged 14-94 years) were cut for cytochrome c oxidase cytochemistry. The photoreceptor layer was microdissected and DNA extracted for 4977-bp mtDNA (mtDNA(4977)) quantification using PCR. Dual cytochemistry for cytochrome c oxidase and succinate dehydrogenase allowed the detection of cytochrome c oxidase-deficient cones.
  
  
  RESULTS
  Findings showed a progressive accumulation of mtDNA(4977) from ages 14 to 94 years. From ages 14 to 60 years there was an increase from 0.006% to 0.25%, and from ages 60 to 94 years there was a steeper increase from 0.25% to 5.39%. Counts of cones in the dual-reacted preparations showed more cytochrome c oxidase-deficient cones in the foveal region than elsewhere.
  
  
  CONCLUSIONS
  The results show that mitochondrial DNA deletions and cytochrome c oxidase-deficient cones accumulate in the ageing retina, particularly in the foveal region. These defects may contribute to the changes in macular function observed in ageing and age-related maculopathy.
authors.affiliation: School of Neurosciences and Psychiatry, University of Newcastle-upon-Tyne, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Barron
authors.forename: M A
authors.initials: MA
authors.lastname: Johnson
authors.forename: R M
authors.initials: RM
authors.lastname: Andrews
authors.forename: M P
authors.initials: MP
authors.lastname: Clarke
authors.forename: P G
authors.initials: PG
authors.lastname: Griffiths
authors.forename: E
authors.initials: E
authors.lastname: Bristow
authors.forename: L P
authors.initials: LP
authors.lastname: He
authors.forename: S
authors.initials: S
authors.lastname: Durham
authors.forename: D M
authors.initials: DM
authors.lastname: Turnbull
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics*; D002452:Cell Count; D030401:Cytochrome-c Oxidase Deficiency / Q000378:metabolism*; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D004587:Electrophoresis, Agar Gel; D005260:Female; D017353:Gene Deletion; D006801:Humans; D008268:Macular Degeneration / Q000201:enzymology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism*
chemical_list: D004272:DNA, Mitochondrial