Age-related changes in the mitochondrial depolarization induced by oxidative injury in human peripheral blood leukocytes

Kelvin Tsai, Tai Ger Hsu, Fung Jou Lu, Chen Fu Hsu, Tsung Yun Liu, Chi Woon Kong

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Aging is associated with impaired immunity and reduced host defenses. Mitochondrial bioenergetic dysfunctions and reduced antioxidative ability of immunocompetent cells may contribute to this phenomenon. In this study, 60 healthy volunteers of different age groups donated their blood after overnight fasting. Leukocytes were subjected to oxidative injuries by exposure to t-butylhydroperoxide, and were labeled with fluorochromes for measuring mitochondria transmembrane potential (Δ ψm), membrane peroxidation and mitochondrial oxidant formation. Δψm declined after t-butylhydroperoxide exposure, and the change was more prominent in leukocytes from older individuals. Cyclosporin A partly restored Δψm, implying the contributing role of mitochondrial permeability transition pores. The mitochondrial depolarization was accompanied by increased oxidant formation and oxidation of pyridine nucleotides, which were more prominent in older subjects. The results support the view that the bioenergetic functions of mitochondria are more susceptible to oxidative injury in aged individuals. The decreased ability of leukocytes to resist oxidative stress may contribute to immunosenescence in humans.

Original languageEnglish
Pages (from-to)395-403
Number of pages9
JournalFree Radical Research
Volume35
Issue number4
Publication statusPublished - 2001
Externally publishedYes

Keywords

  • Aging
  • Cyclosporin
  • Immunity
  • Leukocytes
  • Mitochondria
  • Oxidants

ASJC Scopus subject areas

  • Biochemistry

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