Received wisdom says that staying out in the sun too long will harden your skin over time. Consider the “skinny” complexions of farmers, road crews and others who work long hours outdoors, or those who spend a lot of time in tanning booths.
But, surprisingly, very little research has been done to explain why this happens on a biological level—until now.
A study from researchers at Binghamton University, recently published in the Journal of the Mechanical Behavior of Biomedical Materials, examines how ultraviolet radiation can change the microstructure of human skin. Particularly affected is collagen, the fibrous protein that binds tissue, tendons, cartilage and bones throughout our body.
Leading the research in the Thomas J. Watson College of Engineering and Applied Science’s Department of Biomedical Engineering is Ph.D. students Abraham Ittycheri, Zachary Lipsky, Ph.D., Assistant Professor Tracy Hookway and Associate Professor Guy German.
The new study builds on previous research from German and Lipsky that focused on the outer stratum corneum, which is the top layer of the skin. This time, the Binghamton team compared full-thickness skin samples before and after different levels of UV exposure.
“One way to identify the material characteristics of leather is to conduct a mechanical test to stretch it,” Ittycheri said. “If it’s too easy, it’s quite flexible, but if you stretch it harder, you can tell it’s more rigid. the skin is not exposed to UV light.”
Researchers have found that as the skin absorbs more UV radiation, its collagen fibers become more tightly packed, leading to increased stiffness and tissue that is harder to break. German saw correlations with the cross-linkage theory of aging, which suggests that the accumulation of unwanted molecular bonds over time can cause cellular dysfunction.
“We don’t want to put a fear factor here that says ‘don’t go out in the sun,'” he said. “But long periods of time under UV light can harden your skin as well as lead to a higher risk of carcinogenic problems.”
Hookway—who won a National Science Foundation CAREER Award earlier this year for his research on heart cells—sees similarities between how heart and skin cells deal with injury, even though they have very different functions.
“Our body has this natural response in any tissue when there is some kind of damage, which tends to happen in the stratum corneum,” he said. “First, wherever there is some kind of weakness, there has to be compensation in other parts of the tissue or else there will be catastrophic failure. The same thing happens to the heart when you have a myocardial infarction—you create a scar and your heart never works the same way.”
Sometimes, he added, the body’s reaction continues to be alive but not necessarily a good outcome, which can lead to other medical issues later. Figuring out the mechanics of how it all happens may allow future doctors to guide reactions in a healthier direction.
Following this research, further collaborations with Ittycheri, German and Hookway are in the works. Our skin is the largest organ of the body and the first line of defense against microbes and other external attacks, so ways to maintain and strengthen it are obviously beneficial.
“Any kind of disruption in the normal process of the skin can be very dangerous and detrimental to our overall lifestyle,” Ittycheri said. “That’s not even on the cosmetic side of things, where a person’s perception of themselves can be challenged if their skin doesn’t look good.”
Abraham Ittycheri et al, Ultraviolet light induces mechanical and structural changes in the full thickness of human skin, Journal of the Mechanical Behavior of Biomedical Materials (2023). DOI: 10.1016/j.jmbbm.2023.105880
Provided by Binghamton University
Citation: Bioengineers explore why skin becomes ‘skin’ (2023, July 10) retrieved 11 July 2023 from https://phys.org/news/2023-07-bioengineers-explore-skin-leathery.html
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