Oxidative stress – a key emerging impact factor in health, ageing, lifestyle and aesthetics

Abstract

Oxidative stress is the resultant damage that arises due to redox imbalances, more specifically an increase in destructive free radicals and reduction in protection from antioxidants and the antioxidant defence pathways. Oxidation of lipids by reactive oxygen species (ROS) can damage cellular structures and result in premature cell death. At low levels, ROS-induced oxidative stress can be prevented through the action of antioxidants, however, when ROS are present in excess, inflammation and cytotoxicity eventually results leading to cellular oxidative stress damage. Increasing evidence for the role of oxidative stress in various diseases including neurological, dermatological, and cardiovascular diseases is now emerging. Mitochondria are the principal source (90%) of ROS in the cell, with superoxide radicals being generated when molecular oxygen is combined with free electrons. Given the key role of mitochondria in the generation of cellular oxidative stress it is worth considering this organelle and the process in more detail and to provide methods of intervention.R esum e Le stress oxydatif est l'ensemble des dommages cr ees par les d es equilibres redox, plus pr ecis ement une augmentation des radicaux libres destructeurs et une r eduction de la protection contre les antioxydants et les voies de d efense anti-oxydantes. L'oxydation des lipides par les d eriv es r eactifs de l'oxyg ene peut endommager les structures cellulaires et entraîner la mort pr ematur ee des cellules. A des taux bas, le stress oxydatif induit par les d eriv es r eactifs de l'oxyg ene peutêtre evit ee grâce a l'action des antioxydants. Cependant, quand les d eriv es r eactifs de l'oxyg ene sont pr esents en exc es, l'inflammation et la cytotoxicit e conduisent a des dommages oxydatifs cellulaire. Il existe maintenant de plus en plus de preuves du rôle du stress oxydatif dans diverses maladies, notamment neurologiques, dermatologiques, et cardio-vasculaires. Les mitochondries sont la source principale (90%) de d eriv es r eactifs de l'oxyg ene dans la cellule, avec des radicaux superoxyd es g en er es lorsque de l'oxyg ene mol eculaire est combin ee a des electrons libres. Etant donn e le rôle cl e des mitochondries dans la g en eration de oxydatif cellulaire stress, il est utile d'examiner cet organite et le processus plus en d etail et de proposer des m ethodes d'intervention. Oxidative stressOxidative stress is the resultant damage that arises due to redox imbalances, more specifically an increase in destructive free radicals and reduction in protection from antioxidants and the antioxidant defence pathways [1]. Free radicals are molecules with an unpaired electron [1,2]; there are many types of free radicals; relevant ones are reactive oxygen species (ROS), peroxides, superoxide anion, hydroxyl radical and singlet oxygen. Free radicals, in particular ROS, contribute to oxidative stress through a variety of mechanisms. Interaction with nucleic acids [both in the mitochondria (mtDNA) and in the nucleus (nDNA)] results in mutatio...

Oxidative Stress and Ageing: The Influence of Environmental Pollution, Sunlight and Diet on Skin

“…UVB can also be directly absorbed by DNA, leading to direct induction of damage within cells. Mitochondrial DNA is particularly vulnerable to damage following exposure to UVR as mitochondria have limited DNA repair mechanisms [8]. A recent study looking at the action spectrum of UVR-induced mitochondrial damage showed that mitochondrial DNA is more vulnerable to damage at UVR wavelengths >320 nm when compared with nuclear DNA [25].…”

“…This is of particular importance as there is increasing evidence that alterations in mitochondrial function can adversely impact skin health and lead to skin disease [26]. UVR is therefore able to increase oxidative stress by both direct and indirect means, either by potent stimulation of ROS or by direct DNA damage [8]. This increase in oxidative stress can impair cellular functions, leading to the phenotypic manifestations of extrinsic skin ageing.…”

“…Recently there has been considerable interest in the effects of diet on oxidative stress due to the diet being an important source of exogenously derived antioxidants [8]. Strategies such as diet and exogenous antioxidant supplementation may have a potential role in combating oxidative stress caused as a result of environmental factors.…”

“…The formation of ROS is a natural consequence of oxygen metabolism and ROS have integral physiological roles in cell signalling and oxygen homeostasis [7]. Mitochondria are considered to be the predominant source of intracellular ROS and are believed to contribute 90% of the ROS generated within the cell [8]. In addition to mitochondria, the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system has been identified as an important source of intracellular ROS and a key player in the generation of oxidative stress.…”

“…As the integrity of mitochondrial DNA is essential for mitochondrial function, errors in gene expression may in result in dysfunctional mitochondrial subunits [15]. This leads to a continuous "vicious cycle" where dysfunctional mitochondria contribute to further ROS production, which can lead to further ROS-mediated oxidative damage to mitochondria [8]. Mitochondrial dysfunction is heavily implicated in the ageing process and the pathogenesis of age-related diseases such as Alzheimer's disease (AD) [16].…”