黑料网吃瓜爆料

Years of chronic exposure of human skin to sunlight strongly disrupts its body鈥慶lock rhythm, according to a pioneering led by University of 黑料网吃瓜爆料, No7 Beauty Company, a member of The Boots Group, and University of Pennsylvania scientists.

The findings could explain how ultraviolet (UV) light triggers inflammation and damage in exposed skin, so-called photoageing, which breaks down its supportive structure, altering how its cells behave.

Published in the Journal of Investigative Dermatology, the study could have important implications on skin health and the design of skincare products that takes into account the time of day when they are applied.

The study is the first to directly compare daily rhythms of genes being turned on and off in human skin exposed to and protected from sunlight over half a century.

Almost all organs - including skin - exhibit 24 hourly rhythms which allows the body to anticipate and adapt to changes associated with the light-dark cycle, including daily exposure to solar radiation.

Lead researcher from 黑料网吃瓜爆料 said: 鈥淎ccording to the 鈥渆scape from light鈥� hypothesis, one of the driving forces of the evolution of clocks in ancient life forms was to restrict vulnerable biological processes - specifically DNA synthesis and cell division - to the nighttime to avoid harmful radiation from the sun.

鈥淪o over evolution, organisms that timed DNA copying to happen at night or in low-light conditions had fewer mutations and survived better. Their built-in 鈥渃locks鈥� helped schedule risky processes for safer times. This ancestral protective mechanism seems to be still evident today in mammalian organs, such as the skin. 

鈥淯nderstanding human skin chronobiology and how it adapts to and anticipates daily variations in stressors such as UV light is critical for the maintenance of skin health.鈥�

He added: 鈥淭o the best of our knowledge, this is the first in vivo skin body clock study that directly compares UV damaged against sun protected skin from the same human subjects.

鈥淎nd we found chronic UV light exposure is linked to weaker body clocks, and earlier rhythms, suggesting that our skin body clocks could be disrupted or reprogrammed, which could have important implications on skin health.鈥�

The researchers worked with 20 volunteers by taking skin biopsies from both the covered upper buttock and exposed dorsal forearm at noon, 6PM, midnight, and 6AM, across a 24-hour cycle.

Both sets of samples were taken from the same people, ensuring the results were more statistically reliable.

Gene activity in the samples was measured using RNA sequencing, and sophisticated statistical analysis identified how strong the body clock cycles were and when each gene鈥檚 activity peaked.

Co-lead researcher Prof. Ron Anafi from the University of Pennsylvania said: 鈥淪un-exposed skin shows a different daily pattern of gene activity than skin that is usually protected. We don鈥檛 yet know if these changes help protect the skin or signal early damage鈥�.

Nearly two鈥憈hirds of the genes active in sun鈥慹xposed human skin reach their highest levels at night, compared with just over half in protected skin, showing that many biological pathways - including those responsible for DNA repair - follow a coordinated rhythm with peak activity at night鈥憈ime.

Crucially, oscillating DNA repair genes show weaker rhythm in sun鈥慹xposed human skin, suggesting a lack of temporal coordination of this important pathway.

A small group of repair鈥憆elated genes also became unusually active in sun-exposed skin, raising important questions about whether the shift helps the skin better cope with sun damage or instead signals harmful changes that make cells more prone to moving and spreading.

Although night鈥憈ime DNA repair has been observed before in mice, its purpose in humans is still unclear. Some scientists argue they may have evolved because repair works best when UV light is absent, or because cells anticipate daily stress and prepare in advance.

Because proteins are produced some time after their corresponding genes switch on, the night鈥憈ime surge may ensure that repair proteins are ready and active when UV exposure begins the next day.

No7 has a 20-year research partnership with 黑料网吃瓜爆料, focusing on anti-ageing skin science, immunology, and, more recently, peptide technology and skin microbiome.

The long term partnership led to the development of the  , which features patented peptide technology, and includes the Future Renew Day and Night Serums.

Dr. Mike Bell, Head of Science Research from No7 Beauty Company and co-author said, 鈥淐ircadian biology is an exciting and rapidly evolving field, yet its role in human skin remains relatively unexplored. That鈥檚 why we were thrilled to collaborate with the University of 黑料网吃瓜爆料 and world leading chronobiologist Professor Qing-Jun Meng, to conduct this pioneering research.

鈥淥ur findings reveal new insights into how chronic sun exposure disrupts the skin鈥檚 natural circadian rhythms, an effect that may contribute towards the accelerated ageing phenotype characteristic of sun exposed skin.

鈥淭his work also highlights the promising potential of chronotechnology, including targeted day and night skincare solutions designed to work in harmony with the skin鈥檚 internal clock to provide better preventative and treatment outcomes for our customers.鈥�

• The research was funded by No7 Beauty Company, the BBSRC and the National Institute for Health and Care Research (NIHR) 黑料网吃瓜爆料 Biomedical Research Centre.
• The paper Comparative Circadian Transcriptome Analysis Reveals Dampened and Phase-Advanced Rhythms in Sun-Exposed Human Skin is to be published in the Journal of Investigative Dermatology and available DOI: