Changes in mitochondrial enzymatic activities of monocytes during prolonged hypobaric hypoxia and influence of antioxidants: A randomized controlled study.

Abstract

OBJECTIVES:

Exposure to high altitudes is associated with oxidative cellular damage due to the increased level of reactive oxygen and nitrogen species and altered activity of antioxidant systems. Subjects were submitted to prolonged hypoxia, to evaluate changes in mitochondrial enzyme activities of monocytes and their attenuation by supplementation with antioxidants.

METHODS:

Twelve subjects were randomly assigned to receive antioxidant supplements or placebo prior to and during an expedition to Pik Lenin (7145 m). Monocytes were isolated from blood samples to determine the activity of mitochondrial enzymes cytochrome c oxidase and citrate synthase at 490 m (baseline) and at the altitudes of 3550 m, 4590 m, and 5530 m.

RESULTS:

An increase in citrate synthase activity at all altitudes levels was observed. Hypoxia induced an increase in the activity of cytochrome c oxidase only at 4590 m. Neither citrate synthase activity nor cytochrome c oxidase activity differed between the subjects receiving antioxidant supplements and those receiving placebo.

CONCLUSIONS:

Hypoxia leads to an increase in citrate synthase activity of monocyte mitochondria as a marker of mitochondrial mass, which is not modified by antioxidant supplementation. The increase in mitochondrial mass may represent a compensatory mechanism to preserve oxidative phosphorylation of monocytes at high altitudes.

• Authors: Tobias M Merz, Jacqueline Pichler Hefti, Urs Hefti, Andreas Huber, Stephan M Jakob, Jukka Takala, Siamak Djafarzadeh
• Journal: Redox report : communications in free radical research (Redox Rep) Vol. 20 Issue 5 Pg. 234-40 (Sep 2015) ISSN: 1743-2928 [Electronic] England
• PMID: 25867847 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Antioxidants

Topics

• Adolescent
• Adult
• Aged
• Antioxidants (therapeutic use)
• Atmospheric Pressure
• Female
• Humans
• Hypoxia (drug therapy, enzymology, metabolism)
• Lipid Peroxidation (drug effects)
• Male
• Middle Aged
• Mitochondria (enzymology)
• Monocytes (enzymology)
• Oxidative Stress (drug effects)
• Young Adult