title: Age-related increases in plasma malondialdehyde and protein carbonyl levels and lymphocyte DNA damage in elderly subjects.
abstract: OBJECTIVE
  Increased oxidative stress has been hypothesized to play an important role in the aging process. A role for oxidative damage in normal aging is supported by studies in experimental animals, but there is limited evidence in humans. To investigate the relationship between the oxidative stress and aging in humans, we determined lipid and protein oxidation in plasma as well as DNA damage in lymphocytes in young and elderly subjects.
  
  
  METHODS
  55 healthy subjects were divided into young (21-40 years) and elderly (61-85 years) groups. Plasma malondialdehyde (MDA), protein carbonyl (PC) levels, and grade of DNA damage in lymphocytes using comet assay as well as total ferric reducing antioxidant power (FRAP) in plasma were determined in young and elderly subjects.
  
  
  RESULTS
  Plasma MDA and PC levels were found to be increased in plasma of elderly subjects as compared to young subjects. Increases in endogenous and H2O2-induced DNA damage were also observed in lymphocytes of elderly subjects. In addition, we detected a significant decrease in FRAP values in elderly subjects. Plasma MDA, PC levels and endogenous and H2O2-induced DNA damage were positively correlated with aging, but negatively with FRAP values.
  
  
  CONCLUSIONS
  We evaluated MDA, PC levels and lymphocyte DNA damage altogether in both young and elderly subjects for the first time. The results of this study strongly support the presence of increased oxidative stress in elderly subjects.
authors.affiliation: Department of Biochemistry, Medical Faculty of Istanbul, University of Istanbul, Capa 34093 Istanbul, Turkey. umturk@istanbul.edu.tr
authors.forename: Umit
authors.initials: U
authors.lastname: Mutlu-Türkoğlu
authors.forename: Ebru
authors.initials: E
authors.lastname: Ilhan
authors.forename: Serdar
authors.initials: S
authors.lastname: Oztezcan
authors.forename: Alev
authors.initials: A
authors.lastname: Kuru
authors.forename: Gülçin
authors.initials: G
authors.lastname: Aykaç-Toker
authors.forename: Müjdat
authors.initials: M
authors.lastname: Uysal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000975:Antioxidants / Q000032:analysis; D004247:DNA / Q000187:drug effects / Q000235:genetics; D004249:DNA Damage; D005260:Female; D005290:Ferric Compounds / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008315:Malondialdehyde / Q000097:blood*; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D005290:Ferric Compounds; D011506:Proteins; D008315:Malondialdehyde; D004247:DNA; D006861:Hydrogen Peroxide