Mitochondria, oxidative stress, and antioxidant defences.
Mitochondria are strongly involved in production of reactive oxygen species, considered today as the main pathogenic agent of many diseases. A vicious circle of oxidative stress and damage to cellular structures can lead to either cell death by apoptosis or to a cellular energetic decline and ageing. The early involvement of mitochondria in apoptosis includes expression of pro-apoptotic factors, release of cytochrome c from the inter-membrane space and opening of the permeability transition pore: cytochrome c release appears to precede pore opening. The mitochondrial theory of ageing considers somatic mutations (deletions) of mitochondrial DNA induced by oxygen radicals as the primary cause of energy decline; experimentally, Complex I appears to be mostly affected. We have developed the Pasteur effect (enhancement of lactate production by mitochondrial inhibition) as a bio-marker of mitochondrial bioenergetics in human platelets, and found it to be decreased in aged individuals. Cells counteract oxidative stress by antioxidants; among lipophilic antioxidants coenzyme Q is the only one of endogenous biosynthesis; exogenous coenzyme Q, however, may protect cells from oxidative stress in vivo.
Lenaz
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G
Dipartimento di Biochimica G. Moruzzi, Università di Bologna, Italy. lenaz@biocfarm.unibo.it
Bovina
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C
Formiggini
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Parenti Castelli
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G
D000375:Aging / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis; D015415:Biomarkers; D001792:Blood Platelets / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D018384:Oxidative Stress; D014451:Ubiquinone / Q000378:metabolism
D000975:Antioxidants; D015415:Biomarkers; D014451:Ubiquinone