The battle against skin ageing is undoubtably one of the main forces driving the evolution of the cosmetic field since ancient times. From Cleopatra’s daily milk baths to Elizabeth Báthory’s rather radical blood-bathing habits, the seek for eternal beauty has inspired not only uncountable legends but also the development of a much-needed multidisciplinary research that everyday discovers novel approaches to delay skin senescence. After all, aren’t we all looking for the holy grail of everlasting youth?
Several different aspects can influence the rate and the way our skin ages. Intrinsic factors like hormones, genetic predisposition and neurodegeneration determine the natural cell senescence process throughout our lives. However, extrinsic stressors like UV radiation, pollution, and opportunistic microorganisms can accelerate the decay of the tissue causing premature damage. The stress our skin is subjected to affects not only the cutaneous cells but also the underlying structures that support its function providing innervation, immune protection, and nutrition supply. This coordinated response is carried out by the cutaneous neuroimmunoendocrine system. This complex physiological relation provides the basis for understanding why neuronal ageing plays a big role in the progressive loss of skin elasticity, tone, and firmness. [2,4]
Neuro-ageing is defined as the changes in the nervous system which cause continuous neurodegeneration due to oxidative stress, neuroinflammation or impaired neuromodulators. Amyloid-precursor protein is a membrane protein essential for the synaptic function of the neurons. It is susceptible to oxidative stress resulting in the production of Aβ-neurotoxin. Healthy and young cutaneous neural tissue can counteract this effect and maintain low levels of this toxin. As skin ages, Aβ-toxin accumulates at the nerve endings innervating the tissue, causing disrupted cellular communication, particularly affecting fibroblasts’ ability to synthesize collagen and extracellular matrix. Another way by which skin can be affected by the same mechanism is the decrease of nerve growth factor (NGF) production, which is important for a robust development and maintenance of nerve cells. Different factors can lead to a drop in NGF production, resulting in malfunctioning keratinocytes and reduce lipolytic activity of adipocytes, visibly impacting skin hydration and firmness. [3,4]
"Neurocosmetics content active ingredients aimed at preventing and correcting skin neuro-ageing"
Neurocosmetics are defined as nontoxic cosmetical products, which exert activity over the cutaneous nervous system or neuromodulators. They are part of a category of bordeline products called cosmeceuticals. Ingredients which directly target nerve clusters which regulate hot, cold, itch and pain sensations are already being used to ameliorate the symptoms of skin conditions such as psoriasis or atopic dermatitis. When it comes to anti-ageing neuro-active ingredients in a cosmetic formulation, the aim is not to soothe symptoms, but to prevent and even correct neuro-ageing to promote a long lasting correct cutaneous metabolism. [3]
Several newly developed functional neurocosmetics ingredients intent to act as neuroprotectors. Carotenoids and carbohydrates obtained from brown, red and microalgae have become one of the most promising anti-wrinkle solutions. They possess anti-inflammatory and restorative capabilities which stimulate the synthesis of sAPPα at nerve endings. This neuroprotective protein restores neurone-fibroblast communication, boosting the extracellular matrix and collagen production, reducing the appearance of wrinkles. On the other hand, some newly developed synthetic compounds replace NGF and mimic its activity, restoring skin barrier and improving hydration. Alternatively, natural compounds found in the Ashitaba plant, have been found to enhance NGF production. NGF in turn supports adipocytes activity subsequently reaffirming the skin. [1,3,5]
As we move into a future where technological beauty products will be the new normal, it is clear now that neuro-active compounds are here to revolutionize the cosmetic market. Given that nerve-skin cell communication is present at all levels of the cutaneous tissue, it is sensible to believe that targeting neurodegeneration can reduce skin stress manifestations, ensuring a healthy cellular communication and re-stablishing correct function of the skin’s structures to obtain a long-lasting youthful appearance.
References:
1. Bjørklund, G., Shanaida, M., Lysiuk, R., Butnariu, M., Peana, M., Sarac, I., Strus, O., Smetanina, K., & Chirumbolo, S. (2022). Natural compounds and products from an anti-aging perspective. Molecules, 27(20), 7084. https://doi.org/10.3390/molecules27207084
2. Bocheva, G., Slominski, R. M., & Slominski, A. T. (2019). Neuroendocrine aspects of skin aging. International Journal of Molecular Sciences, 20(11), 2798. https://doi.org/10.3390/ijms20112798
3. Rizzi, V., Gubitosa, J., Fini, P., & Cosma, P. (2021). Neurocosmetics in skincare—the fascinating world of Skin–Brain Connection: A review to explore ingredients, commercial products for skin aging, and cosmetic regulation. Cosmetics, 8(3), 66. https://doi.org/10.3390/cosmetics8030066
4. Roosterman, D., Goerge, T., Schneider, S. W., Bunnett, N. W., & Steinhoff, M. (2006). Neuronal control of skin function: The skin as a neuroimmunoendocrine organ. Physiological Reviews, 86(4), 1309–1379. https://doi.org/10.1152/physrev.00026.2005
5. Thiyagarasaiyar, K., Goh, B.-H., Jeon, Y.-J., & Yow, Y.-Y. (2020). Algae metabolites in cosmeceutical: An overview of current applications and challenges. Marine Drugs, 18(6), 323. https://doi.org/10.3390/md18060323