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Mitochondrial abnormalities in ageing macular photoreceptors
M J Barron1, M A Johnson, R M Andrews
1School of Neurosciences and Psychiatry, University of Newcastle-upon-Tyne, UK.
Investigative Ophthalmology & Visual Science
|November 1, 2001
Summary
Mitochondrial DNA deletions accumulate in the aging retina, especially in the macula. This accumulation of mtDNA(4977) and cone defects may contribute to age-related maculopathy.
Area of Science:
- Ophthalmology
- Gerontology
- Molecular Biology
Background:
- The macula's function declines with age, potentially linked to cellular damage.
- Mitochondrial DNA (mtDNA) mutations are implicated in aging processes.
Purpose of the Study:
- To investigate the accumulation of somatic mitochondrial DNA mutations in the macula during aging.
- To correlate mtDNA mutations with age-related changes in retinal cells.
Main Methods:
- Analysis of 10-microm macular and peripheral retina sections from 14 donors (aged 14-94).
- Quantification of the 4977-bp mtDNA deletion (mtDNA(4977)) using PCR.
- Detection of cytochrome c oxidase-deficient cones via dual cytochemistry.
Main Results:
- A progressive accumulation of mtDNA(4977) was observed with age, increasing significantly after 60 years.
- The prevalence of mtDNA(4977) rose from 0.006% at age 14 to 5.39% by age 94.
- More cytochrome c oxidase-deficient cones were found in the foveal region compared to other retinal areas.
Conclusions:
- Mitochondrial DNA deletions and deficient cones increase in the aging retina, particularly in the macula.
- These age-related cellular defects may underlie functional decline and age-related maculopathy.