Despite the existence of a multi-billion dollarthe skin care industry and a host of marketing applications, there is nothing that could prevent our skin from turning into papyrus with age. Except, perhaps, sunscreen if used every day. Accumulated damage from ultraviolet radiation and other age-related stressors depletes skin cells for renewal — or stem cells — and it is impossible to stop or slow down this process.
But there is still hope. A study published in Nature in early April gives a new insight into how stem cell loss occurs and even identifies two chemicals that can prevent it.
How to keep the skin young?
Research by a professor of biologyAmy Nishimura’s stem cells from the Tokyo Medical and Dental University in Japan showed that aging and ultraviolet exposure deplete the stem cells of the most important collagen protein. Those who are concerned about the health of their skin are well aware that collagen is one of the most important players in maintaining strong, young, elastic skin. Weakened stem cells can no longer divide normally and are eventually forced to turn into adult skin cells. Over time, so many stem cells are damaged that there are not enough healthy ones to replace them.
"I think this study is beautiful,"says David Fisher, a professor of dermatology at Harvard Medical School, who did not participate in the study. "I think this is a very elegant analysis, which also revealed practical mechanistic ideas about what is happening, and even potentially effective, contributing to rejuvenation."
Our skin is divided into two parts: epidermis above and dermis below. The epidermis is what we usually call skin, it consists of many layers of cells; The dermis consists of connective tissue, hair follicles, blood vessels, and sweat glands.
As part of normal healthy skin, the top layerThe epidermis is constantly peeled off and replaced from a self-repairing stem cell pool, which is located in the lower (or basal) layer. These stem cells have roots that attach to a thin piece of tissue called the basement membrane - it connects the epidermis and the dermis. Binding to the basement membrane is important for maintaining the “stem” state of the cell - its ability to multiply and mature into another type of cell.
For most of the time, stemcells in the epidermis divide horizontally, cloning themselves and adding to the update pool. However, sometimes they are divided vertically, and a new cell begins to mature into an adult cell of the skin, which is gradually pushed up through the layers of the epidermis.
This type of cell exchange is the replacement of old cells.in the upper part of the epidermis with younger cells below - explains how cuts heal and how the skin remains young in appearance. However, with age, the stem cell pool is depleted and cell turnover slows down, leaving people with thin, fragile skin.
"The main question that is trying to solve itresearch - why cells becomes less? Why do we lose stem cells as we grow up? ”, Says Terry Lechler, an assistant professor of dermatology at Duke University, who was not involved in the study. "I think this is a really interesting question, the very essence."
The study suggests that stem cellswhich divide vertically do so due to damage due to normal aging and the normal cell turnover process, as well as exposure to ultraviolet light or any other toxins. And not only the new adult cell begins its journey through the epidermis - the original stem cell also repels the basal layer, which leads to its maturation. This is due to the fact that the roots of the damaged cell weaken, so they can no longer be successfully attached to the basement membrane. Researchers describe this step as a sort of competition when neighboring healthy stem cells combine and expel weak stem cells from the island.
"It seems to be related to the control mechanismthe quality that makes a skin stem cell that is damaged is removed from the skin, ”says James De Gregory, a professor of biochemistry at the University of Colorado in Denver. "You can imagine that all these stem cells are fighting for the position, and if you grab the basement membrane, you will do better."
At first this competition is beneficial.ridding the skin of defective cells or even cancer-causing mutations. However, at some point too many stem cells become damaged and begin to outnumber healthy cells. When this happens, the skin can no longer effectively rejuvenate or respond to injury. "The stem cell competition among epidermal stem cells keeps the skin young, but the decline in competition ends with aging," explains Nishimura.
The basis of this process is collagen-17,A special type of collagen protein that is essential for stem cell rooting in the basement membrane. When stem cells get damaged, they lose a valuable amount of collagen-17. The more protein they lose, the weaker their connection with the basement membrane, until ultimately they are not crowded out by adjacent healthy cells.
The good news is that there may bea way to increase or maintain the level of collagen-17 in stem cells, preventing this skin aging process. Nishimura showed that two experimental chemicals, Y27632 and apocynin, when applied topically, can increase the level of collagen-17 in the cells and even promote wound healing.
This does not mean that you should run toa pharmacy and buying products with the content of “collagen” or “stem cells” on the label - there is no evidence that there is anything on the market at all. But this means that on the horizon anti-aging cream, which supports science.
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