Oxidative Stress

Anti-Pollution Matrix > Damage > Molecular > Oxidative Stress

Explanation

In general, oxidative stress is manifested by an increased concentration of free radicals in the organism, resulting in an imbalance between the body's antioxidant defense system and reactive metabolites. The resulting free radicals are in most cases oxygen radicals (reactive oxygen species, ROS). These include superoxide anion radicals (O2-), hydroxyl radicals (OH-), hydrogen peroxide (H2O2) and singlet oxygen (1O2). However, they also include reactive nitrogen species (RNS), which can promote lipid peroxidation reaction cascades and lead to inflammatory responses [1, 2]. It has been widely demonstrated that various types of pollution, such as particulate matter, soot, etc., but also sunlight lead to increased oxidative stress in the skin and its cells.

 

Effects on the skin

If excessive radical formation occurs, e.g., due to sun exposure or air pollutants, increased oxidation of cellular components such as membranes, lipids, proteins and nucleic acids may occur, promoting cell and tissue damage (inflammation).

UV radiation penetrates the skin and can induce the production of ROS. In addition, some pollutants on the surface or in the skin can induce the production of ROS. The combination of UV radiation and pollutants can enhance the biochemical and clinical effects of air pollutants [3].

ROS can attack any molecule or cellular structure. Oxidative damage to DNA results in a variety of modified purine and pyrimidine bases. Due to its low ionization potential, the purine base guanine is the most unstable base and thus the main point of attack for oxygen radicals. In the presence of ROS, the carbon atom in the C8 position of guanine is preferentially hydroxylated and 8-oxo-2'-deoxyguanosine (8-oxodG) is formed. Pollution damages not only the mucosa in the lungs, but also the skin. This promotes the development of oxidative stress in the skin, resulting in premature skin aging (changes in the collagen-elastin content of the skin), damage to the skin barrier, pigmentary disorders and cell damage caused by free radicals. Furthermore, changes in the skin microbiome in favor of pathogenic agents are favored, there is an altered sebum production and also the pH value of the skin deviates from the normal range [2,4].

 

Measures

To better control and minimize damage that can be caused by ROS, free radicals are countered by the skin's antioxidant protection system, which consists of enzymatic and non-enzymatic antioxidants (AOs). These can be either endogenous (produced by the skin itself) or exogenous (supplied with food or topically with creams). Lightweight AOs in skin care are vitamins, such as vitamin E and vitamin C, and derivatives thereof. [2]. Further, natural extracts of, for example, plants or algae also contain a variety of molecules with antioxidant activity.

In order to counteract harmful environmental influences, more and more skin care products with anti-pollution effects have appeared on the cosmetic market in recent years. Such products are intended to reduce the risk of, among other things, premature skin aging, pigment spots and skin irritations and to support the skin in its protective action against the formation of free radicals (ROS) [5].

 

Impact detection methods

Various detection methods are available for the detection of free radicals/ ROS.

Electron spin resonance (ESR) spectroscopy is a sensitive non-invasive method for the detection of radical formation in tissue (in vivo/ex vivo) and also in cells. The use of various ESR probes allows the quantification and characterization of radicals.

In addition, there are many fluorescence-based methods that can be used to detect total ROS concentration in tissue/cell culture; but also the detection of specific oxidation products of different cell components is possible, such as DNA components (comet assay) or oxidized lipids and proteins. These detection methods are based on the detection of fluorogenic compounds through the use of fluorescence spectroscopy, which can be easily influenced by the light scattering properties of the subjects under investigation, leading to misinterpretation and incorrect results.

The DCF assay is also used to detect oxidative stress. Here, the oxidation of 2', 7'-dichlorofluorescin diacetate (DCF-DA) to the fluorescent compound 2', 7 'dichlorofluorescein (DCF) is detected due to the presence of reactive oxygen species (ROS).

 

References

[1] H. Sies, Oxidative stress: a concept in redox biology and medicine, Redox Biol, 4 (2015) 180-183, doi: 10.1016/j.redox.2015.01.002
[2] M. Valko, D. Leibfritz, J. Moncol, M.T. Cronin, M. Mazur, J. Telser, Free radicals and antioxidants in normal physiological functions and human disease, Int J Biochem Cell Biol, 39 (2007) 44-84, DOI: 10.1016/j.biocel.2006.07.001
[3] E. Araviiskaia, E. Berardesca, T. Bieber, G. Gontijo, M. Sanchez Viera, L. Marrot, B. Chuberre, B. Dreno, The impact of airborne pollution on skin, J Eur Acad Dermatol Venereol, 33 (2019) 1496-1505, DOI: 10.1111/jdv.15583
[4] J Rembiesa, T Ruzgas, J Engblom, A Holefors, The impact of pollution on skin and proper efficacy testing for anti-pollution claims, Cosmetics, (2018) 5 1-9, https://doi.org/10.3390/cosmetics5010004
[5] M Portugal-Cohen, M Oron, D Cohen, Z Ma'or Z, Antipollution skin protection - a new paradigm and its demonstration on two active compounds. Clin Cosmet Investi, 10 (2017)185-193, doi: 10.2147/CCID.S129437