Oxidative stress and ageing: is ageing a cysteine deficiency syndrome? (氧化壓力與老化：難道老化是缺乏 半胱胺酸 所引起的症候群嗎？)

Philos Trans R Soc Lond B Biol Sci. 2005 Dec 29; 360(1464): 2355–2372.
Published online 2005 Nov 3. doi: 10.1098/rstb.2005.1770
PMCID: PMC1569588

Oxidative stress and ageing: is ageing a cysteine deficiency syndrome?
氧化壓力與老化：難道老化是缺乏 半胱胺酸 所引起的症候群嗎？

Wulf Dröge
Division of Redox Physiology and Aging Research, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany

ABSTRACT
Reactive oxygen species (ROS) are constantly produced in biological tissues and play a role in various signaling pathways. Abnormally high ROS concentrations cause oxidative stress associated with tissue damage and dysregulation of physiological signals. There is growing evidence that oxidative stress increases with age. It has also been shown that the life span of worms, flies and mice can be significantly increased by mutations which impede the insulin receptor signaling cascade. Molecular studies revealed that the insulin-independent basal activity of the insulin receptor is increased by ROS and downregulated by certain antioxidants. Complementary clinical studies confirmed that supplementation of the glutathione precursor cysteine decreases insulin responsiveness in the fasted state. In several clinical trials, cysteine supplementation improved skeletal muscle functions, decreased the body fat/lean body mass ratio, decreased plasma levels of the inflammatory cytokine tumour necrosis factor α (TNF-α), improved immune functions, and increased plasma albumin levels. As all these parameters degenerate with age, these findings suggest: (i) that loss of youth, health and quality of life may be partly explained by a deficit in cysteine and (ii) that the dietary consumption of cysteine is generally suboptimal and everybody is likely to have a cysteine deficiency sooner or later.

Keywords: cysteine in vivo, redox status, muscle functions, immune functions, inflammatory cytokines, insulin signaling, aging

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Properly done, cysteine supplementation can reasonably be expected to improve the quality of life in old age. With the availability of novel cysteine delivery systems with minimum amounts of calories, which are superior to any of the naturally available cysteine sources, it is conceivable that even the maximum human life span may be increased beyond the previous limit.

ACKNOWLEDGMENTS