THE Rides obsess us so much that we are ready to smear our faces with almost anything to prevent them from colonizing our skin… without much success. Because we still do not understand very well how these wrinkles are formed, only that age favors their appearance (because of the thinning of the skin with aging) and that factors such as dehydration do not help.
But studying this phenomenon closely is very difficult. Because animal models do not allow us to follow what is happening in the skin at the cellular and molecular level in real time. And in vitro models are not sufficiently similar to real skin conditions.
However, a new approach appears to mimic skin and other surfaces lined with epithelial cells (like those that line our intestines) more realistically. Wrinkles in a Petri dish, which could help us better understand how wrinkles appear, and how to prevent them! This new model was presented on August 19, 2024 in the journal Nature Communications by researchers at Pohang University of Science and Technology in South Korea.
Wrinkles are formed due to compression of the skin
Their fake skin is made from real epithelial cells (lines from the intestines or lungs). On a hydrogel composed of collagen, the elastic protein that forms a large part of the epidermis (the last layer of the skin) and other epithelial tissues. This double layer, which mimics the composition of these tissues, is placed in a device that allows it to be compressed in order to study how mechanical pressures, such as muscle contraction, induce the appearance of wrinkles.
First result: the shape of the wrinkles depends on the pressure exerted on the epithelial tissue. At first, the compression stiffens the layer of cells, then it generates a multitude of very small wrinkles, like waves on a calm sea. But when the pressure increases, these wrinkles combine to form a single fold, our famous wrinkles.
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Hydrogel properties influence wrinkle formation
The researchers also tested their device on layers of epithelial cells without the second layer of collagen. In this case, the cells deformed under pressure and formed folds much more quickly, under a lower compression than that necessary when the cells are protected by collagen. Confirming the importance of this protein in the maintenance of the skin and other epithelial tissues.
The dehydration of this bilayer was also significant, promoting the formation of wrinkles. With compression, water is pressed outwards, like in a wet cloth that is wrung out. This loss of water depends directly on the density of the collagen: the more there is, the more it catches the water and prevents it from leaving under pressure. When the collagen concentration was higher, the compression of the bilayer did not generate the small wrinkles observed previously, but rather a large loop, which deformed the tissue less.
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“ We have designed a platform that can replicate different wrinkle structures in living tissue without requiring animal testing," "The study's authors, Dong Sung Kim, are pleased in a press release. He hopes that this new approach will allow research on wrinkles, particularly in the cosmetic, to become more ethical and more precise.
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