Photoaging is 80% of Extrinsic Aging
A physical barrier between the inside and the outside, the skin is one of the most responsive organs to external aggressions, particularly to UV radiation. Amongst all environmental factors responsible for extrinsic aging, repeated sun exposure is the most significant. Photoaged skin features a set of typical modifications: wrinkles and fine lines, altered microrelief, lack of luminosity, and pigmentary disorders.
About Sun Rays
For decades, UVB rays have been considered more genotoxic than UVA. UVB rays are known to severely damage the epidermis, causing local inflammation and sunburns while penetrating the heart of cells in DNA. Their role in the generation of photoproducts and direct DNA lesions is clearly established.
Due to the UVA rays’ capacity to penetrate deeper layers of the skin, UVA was mainly related to structural alterations of the dermis through the breakdown of collagen and elastin networks. However, today’s scientific publications have shown evidence that UVA radiation is not as innocuous as previously thought to be.
UVA radiation is 20× more abundant in solar radiation than UVB. It penetrates further into the skin with damage described on the different skin layers, dramatically increases the oxidative stress level in the skin, generates oxidative DNA lesions, and reduces the efficacy of DNA repair systems.
More precisely, research has shown that UVA is very likely to induce DNA lesions in the epidermal basal layer, which hosts the keratinocyte stem cells.
Studying UVA Impact on the Epidermis
A few years ago, the Gattefossé skin biology team partnered with a research group that specializes in the interactions between UV and DNA to study the effects of UVA radiation on keratinocyte stem cells. The integrity of these epidermal mother cells and their protection against environmental aggressors are key to ensuring the long-term function and health of the epidermis.
Out of this collaboration, it was discovered that although keratinocyte stem cells benefit from very efficient DNA protection and repair systems, they can still be affected by UVA. DNA lesions induced by UVA in keratinocytes are associated with a weakening of their self-renewal capacity, their so-called “stemness” potential, ultimately related to functional and structural alterations of the epidermis.
Out of this work, an all-natural active ingredient named Solastemis™ has been developed1, acting at the heart of the epidermis mechanics by protecting the DNA of keratinocytes from lesions induced by UVA radiation; boosting the endogenous DNA repair system and preserving the keratinocyte stem cells.
Solastemis™ also offers a shield for the extra-cellular matrix by protecting key macromolecules (collagen, elastin) from degradation induced by solar exposure.
A double-blind clinical trial confirmed Solastemis™ efficacy on various symptoms of photoaging versus the placebo. Solastemis™ efficiently reduces crow’s feet wrinkles and improves skin smoothness. Skin tone is embellished for a more lucent, glowing, and even complexion.
Solastemis™ is derived from chayote (Sechium edule), a fruit cultivated and manually harvested on Reunion Island (French oversea territory) in the majestic Cirque of Salazie. The extraction with a NaDES solvent makes an eco-designed ingredient (99.85% content of natural origin, according to ISO16128) associated with high biological performance.
(1) Metral E., Rachidi W., Damour O., Demarne F., Bechetoille B., Long-term Genoprotection Effect of Sechium edule Fruit Extract Against UVA Irradiation in Keratinocytes, Photochemistry and Photobiology, 2018, 94: 343–350
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