Two new molecules that release tiny quantities of hydrogen sulfide have been found to prevent skin from ageing after being exposed to ultraviolet light found in sunlight. The study was published in Antioxidant and Redox Signalling.
For the study, the researchers exposed adult human skin cells and the skin of mice to ultraviolet radiation (UVA). UVA causes skin ageing by turning on collagenases, enzymes which eat away at the natural collagen, causing the skin to lose elasticity, sag and wrinkle. UVA also penetrates deeper into skin than the UV radiation that causes sunburns (UVB), and it also damages cellular DNA, leading to mutations that can contribute to some skin cancers. Typical sun creams sit on top of the skin and absorb UV radiation, but they do not penetrate the skin where the long-lasting damage occurs.
For deeper protection, the researchers came up with a new way to protect the deeper layers of skin using two compounds invented at the University of Exeter: AP39 and AP123. The compounds do not protect the skin in the same way traditional sun creams prevent sunburn, but instead penetrate the skin to correct how skin cells’ energy production and usage was turned off by UVA exposure. This then prevented the activation of skin-degrading collagenase enzymes.
The compounds used in this study were previously shown to have impressive effects in reducing skin inflammation and skin damage after burn injury and atopic dermatitis (eczema). In an anti-ageing context, they prevented human skin cells in test tube experiments from ageing, but this is the first time the effects of photo-ageing have been seen in animals.
The important observation noted was that the compounds only regulated energy production, PGC-1α and Nrf2 in skin that was exposed to UVA. This suggests a novel approach to treating skin that has already been damaged by UV radiation, and could potentially reverse, as well as limit, that damage.
While further research is needed, there could be medical as well as cosmetic implications from this work, where protecting skin from UV light is important. For example, not only premature skin ageing and skin cancers, but UV light allergies, solar urticaria and rare hereditary skin diseases such as xeroderma pigmentosum. The researchers are currently partway through testing newer and more potent molecules able to do the same task using newer approaches.
Source: University of Exeter
