How to repair damaged skin barrier?

It’s the season change again, ladies, how is your skin? Many friends have said that they use skin care products/sunscreen a lot, so why is the skin barrier still damaged?

Regarding skin barrier damage, generally if it is slightly damaged, our body's repair ability will restore it to normal as soon as possible. However, if the skin barrier is damaged for a long time, it will be very difficult to repair. I believe this is also a problem for many people. Once the skin barrier is damaged, many methods will not work. What is going on? Let's talk about it today.

01. Why is it difficult for the skin barrier to repair itself after long-term damage?

Many people are curious. It stands to reason that our human cells have a strong ability to repair damaged cells. Even if they cannot be repaired, there is a special apoptosis system that causes cells to die and then replace them with new cells, forming a metabolism of old and new cells. Why is it difficult for the skin barrier to be restored through this self-repair system when it is damaged for a long time?

In fact, this situation may be due to the aging of skin cells. Cell aging is different from normal metabolism. Aged cells show aging but not apoptosis. Not only that, they will maintain this state of the skin, causing normal metabolism to be blocked. Even if repair nutrients and drugs are used, it seems to be relieved in the short term, but once the drugs are stopped, aging will continue to take effect and cause the skin barrier to become damaged.

This puzzles many people. Why can’t our damaged skin barrier be repaired even though our genes haven’t changed and our bodies are metabolizing normally? What magic does aging have that can continue to damage the skin barrier? In fact, this has a lot to do with epigenetics of aging.

02. What is epigenetic inheritance?

When it comes to heredity, I believe many people understand that it is related to genes, which are passed down from parents to the next generation. Basically, everyone's genes are basically fixed when they are born, and the inheritance they receive is also established. This is classical genetics. However, in recent years, scientists have discovered another kind of inheritance, that is, epigenetic inheritance. This kind of inheritance is different from classical genetics. They are affected by acquired factors and can pass on this inheritance. This is a bit like the Lamarckianism of "use it or lose it" that many people have known.

This phenomenon was first observed in mice. When mice are subjected to continuous stimulation, they will develop a startle response to the stimulation. Researchers then discovered that this behavior does not fade over time. What is more serious is that such mice can actually pass this memory on to the next generation. Even if the next generation has never been exposed to the relevant stimulation, they still maintain a strong startle response to the stimulation. It should be noted that simple stimulation cannot change the gene sequence, so this mode of inheritance is different from our classic inheritance, so scientists named it epigenetic inheritance [1].

03. Epigenetics also exist in the human population

Subsequently, more and more studies revealed that epigenetic inheritance is not only present in mice, but also in other species, including humans. For example, during World War II, the Netherlands was besieged, which led to the Dutch famine in 1944. When faced with hunger, the synthesis of insulin-like growth factor IGF2, which is related to energy metabolism, decreased in the human body. After the end of World War II, even though people's living standards were restored or even greatly improved, this low expression of IGF2 has been maintained in the group born during the famine. Even today, 60 years later, this situation still exists. This is one of the evidences of epigenetic inheritance in the human population [2].

During the aging process, epigenetic changes also occur, and a large number of epigenetic changes occur during the aging process[3]

This process will show the loss of overall histones, the balance of histone activation and inhibition will be broken, and further lead to the disorder of gene transcription. If this regulation continues, it will show that the overall gene expression in aging cells has changed, and because epigenetic inheritance, once it occurs, will often be maintained continuously, so aging cells are very difficult to repair and the skin barrier is difficult to be well resolved. This is also the biggest problem in skin care.

04. How to deal with this phenomenon?

So is there really nothing we can do? Of course not. Epigenetics ultimately comes down to gene expression, and it works by affecting gene expression. If we can find factors that can regulate gene expression, we can improve aging.

Micro RNA is just such a molecule. There is a region at the end of our gene, which we call 3'UTR (Untranslated Regions). This region is not translated, but it is the region where micro RNA binds. MicroRNA can regulate gene expression well by binding and dissociating with this region.

Since miRNA can be synthesized in vitro, it has greatly facilitated research in the biomedical field, eliminating the need for extensive genetic manipulation to interfere with genes. This has promoted the entire biomedical field's research on gene expression regulation, and it won the Nobel Prize in 2006. Today, miRNA has been promoted to clinical applications, playing a huge role in treating many diseases that are difficult to treat with traditional medicine [5].

This strategy can also be applied to the repair of damaged skin barrier. Unlike traditional drugs, damaged skin barrier is a process of cell aging, and gene expression is continuously changed due to epigenetic changes. In this case, using miRNA to relieve epigenetic changes is the right medicine.

It can be said that this is a commendable practical application in the field of aging epigenetics in recent years. Currently, research in the field of aging is still ongoing, such as the metformin experiment. I believe that with the advancement of a large amount of research, in the future we will not only be able to solve the problem of skin cell aging, but even systemic individual aging may be reversed.

1. Dias, Brian G., and Kerry J. Ressler. "Parental olfactory experience influences behavior and neural structure in subsequent generations." Nature neuroscience 17.1 (2014): 89-96.

2. Heijmans BT, Tobi EW, Stein AD, et al. Persistent epigenetic differences associated with prenatal exposure to famine in humans[J]. Proceedings of the National Academy of Sciences, 2008, 105(44):

3. Rando, Thomas A., and Howard Y. Chang. "Aging, rejuvenation, and epigenetic reprogramming: resetting the aging clock." Cell 148.1-2 (2012): 46-57.

4. Bird A. DNA methylation patterns and epigenetic memory[J]. Genes & development, 2002, 16(1): 6-21.

5. Zimmermann, Tracy S., et al. "RNAi-mediated gene silencing in non-human primates." Nature 441.7089 (2006): 111-114.