Recent reassessment of the role of reactive oxygen species (ROS)
- 15.09.2013
- English Articles
- Sebastian Schmeißer
- Michael Ristow
- Marc Birringer
Peer-reviewed | Manuscript received: February 21, 2013 | Revision accepted: July 02, 2013
Introduction
The use of oxygen to oxidize macromolecules as part of an aerobic metabolism is considered a basic prerequisite for the formation of higher life forms. The transformation of nutritional energy to the available cellular energy equivalents (for example ATP) is much more efficient here than for the oxygen-free/anaerobic generation of energy. Numerous biological processes can thus be supplied with sufficient energy, supporting cellular energy homeostasis.
However, the use of oxygen leads to the formation of so-called reactive oxygen species (ROS). Due to their highly reactive nature, ROS are considered to be potentially toxic molecules capable of damaging cellular components and thus restricting their function. The discovery that cellular damage accumulates throughout life and ultimately leads to the death of the cell or organism, as well as the fact that ROS can cause damage, leads to the assumption that there is a causal relation. Accordingly, numerous studies consider ROS formation to be one possible cause for the occurrence of ageassociated diseases, as well as for the ageing process per se. This research has led to the wide-spread opinion that ROS are invariably damaging and that reduced occurrence or intervention is associated with positive health effects.
Summary
Reactive oxygen species (ROS) are closely related to pathogenic age-associated diseases, such as arteriosclerosis, diabetes and cancer. Here, important macromolecules, such as proteins, lipids or genetic information in the form of DNA, are irreversibly altered. Apart from the intensively investigated negative properties of ROS, recent studies show that these molecules have signaling functions and that a balance must be maintained between the formation of ROS and the elimination by the antioxidative enzymes and antioxidants. This implies that an excess in ROS causes damage to the organism. However, complete elimination of ROS inhibits the organism’s capacity to react to external stress factors in the form of an adaptive stress response. This research is described here under the term hormesis or mitohormesis and a re-evaluation of reactive oxygen species is carried out.
Keywords: reactive oxygen species (ROS), antioxidants, calorie restriction, ageing, extended life span, physical exercise, mitohormesis, hormesis
