Age-associated accumulation of 8-hydroxydeoxyguanosine in mitochondrial DNA of human diaphragm.
This is the first report that age-associated accumulation of 8-hydroxydeoxyguanosine (8-OH-dG) does occur in human mitochondrial DNA (mtDNA) in muscle of diaphragm. We extracted mtDNA from human diaphragm muscles from differing age groups, and determined the amount of 8-OH-dG by ultramicro-high performance liquid chromatography/mass-spectrometry system. With the same specimen, multiple deletions of mtDNA were detected by electrophoresis after amplification by the polymerase chain reaction method. In subjects below age 55, the level of 8-OH-dG in mtDNA was below 0.02% of the total deoxyguanosine (dG), whereas, in subjects over age 65, the level of 8-OH-dG increased with age at a rate of ca. 0.25% per 10 years, reaching 0.51% at age 85. Moreover, a concomitant increase in multiple deletions was detected with the increase in age. These results suggest that, in younger diaphragms, replication of mtDNA dilutes out 8-OH-dG being not detectable. In the elderly subjects aged over 65, the replication rate might be slowed down leading to the accumulation of 8-OH-dG in mtDNA, which would accelerate the age-associated multiple deletions of mtDNA observed among the subjects.
Hayakawa
M
M
Department of Biomedical Chemistry, Faculty of Medicine, University of Nagoya, Japan.
Torii
K
K
Sugiyama
S
S
Tanaka
M
M
Ozawa
T
T
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D002872:Chromosome Deletion; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000378:metabolism*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D003964:Diaphragm / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction
D004272:DNA, Mitochondrial; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine