This is a contemporaneous photo of a pair of twin sisters.
The left sister has been farming for a long time, exposed to a large amount of ultraviolet rays every day and has no effective protection, compared with the sister on the right who lives in the city, the degree of skin aging is obvious.
Compared to natural aging, 80% of the skin's aging is due to photoaging.
With the increasing demand for "anti-aging", in addition to traditional sun protection, many skin care brands have played a new concept - "DNA repair" and "reverse light aging".
But can photodamed DNA really be repaired? How is this technology being applied in the skincare industry? How do they help us "fight aging"?
In this issue, Yanyan invited the sunscreen expert Guang Yanjun to answer questions and introduce several related products for everyone, and interested saccharin can taste it! (There is a summary at the end of the article, oh, lazy people must see!) ）
01
Photoaging and DNA damage
To understand DNA repair, we still have to start with the "culprit" of photoaging.
The mechanism of UV-induced DNA damage, and its association with photoaging, can be summarized as the following figure:
Direct damage to DNA is mainly caused by UVB. UVB has a shorter wavelength and higher energy, which is the main culprit of skin redness and sunburn.
Specifically, it directly attacks the DNA of skin cells, and this damage causes mutations in our DNA, mainly forming CPD (cyclobutanepyrimidine dimer), (6-4) PP (6-4photoproducts, pyrimidine (6-4) pyrimidone photoproduction) and their associated Dewarvalence isomers.
Indirect damage to DNA, mainly caused by UVA. UVA has low energy and long wavelengths, making it easier to penetrate the dermis layer, causing tanning and aging.
It indirectly causes oxidative damage to DNA mainly by causing the skin to produce large amounts of ROS reactive oxygen species. This damage can also lead to DNA mutations, mainly cpD.
UVA can also convert (6-4) PP into Dewar valence bond isomers.
The damage of ultraviolet rays to DNA can lead to apoptosis and damage to our skin cells, resulting in excessive stress response, leading to skin inflammation.
At the same time, the expression of MMPs metalloproteinase is upregulated, destroying the skin collagen fibers, resulting in a decrease in collagen fibers and elastin fibers, decreased collagen synthesis, abnormal elastin fiber deposition, and disappearance of the extracellular matrix, which eventually leads to the appearance of aging symptoms such as rough skin, sagging, sagging, increased pigmentation and wrinkles.
In addition, it will also lead to the production of skin AGEs saccharification products, increase the expression of AGEs receptors, impair cell differentiation, induce cell aging, reduce cell viability and migration ability, and accelerate aging.
In general, the core cause of skin photoaging caused by ultraviolet rays is damage to the DNA of our skin cells. That's why today's skincare technology is exploring dna repair.
02
"Life-changing" DNA repair enzyme
In fact, the topic of DNA repair has been studied for decades, but breakthroughs have been made in the past decade.
Three scientists who have made great contributions to the field of DNA repair also jointly won the 2015 Nobel Prize.
(2015 Nobel Laureates in Chemistry: Thomas Lindal, Paul Modric and Aziz Sanjar)
First, we have a set of DNA repair and error correction mechanisms. When the skin is damaged by UV rays, our own repair mechanism will perform excision repair.
Simply put, our body has a nucleic acid endonuclease that will help us clear the CPD generated due to DNA damage, remove the part that is in trouble, and let everything return to normal.
In addition to this mechanism, there is also a type of photolysis repair, which is the focus of current skin care applications.
Professor Aziz Sancar, one of the winners of the 2015 Nobel Prize in Chemistry, said in his Nobel Prize acceptance speech that he was inspired by the phenomenon of bacteria "changing their lives against the sky" after ultraviolet killing.
When these bacteria are killed by ultraviolet light, through blue light, these bacteria are miraculously revived, because of the presence of a special enzyme in the bacteria, which can absorb blue light and use that energy to repair DNA.
Since then, Professor Aziz Sancar has been working on this enzyme, which is photolyase; this phenomenon of bacteria changing their lives against the sky is called photoreactivation.
This way of DNA repair through photolysis enzymes is extremely closely related to our skin care and photoaging, and it is also a new technology and direction for skin care and anti-photoaging.
The mechanism by which we humans repair DNA is extremely complex, by cutting off the part that has gone wrong and synthesizing a new one to get the DNA back to normal.
The repair of photosyphenase is a direct repair mechanism, the photolysis is activated under the action of visible light, will bind to the CPD at the site of DNA damage, reverse the CPD, and restore it to a normal state.
However, this enzyme has only been identified in bacteria, yeast, insects, plants, and marsupial mammals, while photolases or analogues have not been identified in other mammals, including humans. That is, our human cells do not have light lyases.
Therefore, the current skin care technology refers to DNA repair, which is to introduce light lyases from other species into human cells in order to more effectively repair CPD and repair DNA damage caused by ultraviolet light.
Compared with the anti-photoaging mechanism that we are familiar with, DNA repair is a completely different mechanism and pathway.
The role of common sunscreen products on the market is mainly to block ultraviolet rays and reduce the damage of ultraviolet rays to our skin.
However, even if the sunscreen product is marked with SPF and PA values, the amount of application is generally insufficient when people use it daily.
Such as SPF50 sunscreen, the amount of application in human testing is 2mg per square centimeter, but the amount of application we use daily basically does not reach this level, generally about 0.7-0.8mg.
Therefore, the actual ultraviolet blocking ability of these sunscreen products is difficult to achieve the corresponding effect.
In addition, we will also use some antioxidant products, their core mechanism is that ultraviolet rays damage the skin after inducing ROS, and antioxidants can remove ROS, reducing further damage to the skin by ROS.
But the mechanism by which antioxidants remove ROS is a one-time trade, and while removing ROS, the antioxidants will also fail.
The different mechanisms of action of DNA repair technology should theoretically produce better synergy with our existing technologies and ingredients, and more comprehensive resistance to photoaging.
03
Applications in the field of skincare
At present, the DNA repair enzymes used in the field of skin care mainly include the following:
· Photolysomes: DNA repair enzymes extracted from plankton
· Mitosomes: DNA repair enzyme extracted from the mustard plant Arabidopsis thaliana
These DNA repair enzymes are mainly wrapped in liposomes through microcapsule technology, which can better improve the stability of the active substance, and the main component of the liposome is phospholipids, and the similarity of phospholipids and our skin components will also allow the active substances to have better penetration.
The particle size of the liposome will also be controlled at about 150 nanometers to ensure the performance of the efficacy.
In general, these active ingredients penetrate into the epidermis layer of our skin within an hour. After penetrating into our skin, the outer lipid dissolves due to changes in the pH value, releasing the encapsulated active ingredients.
However, the exact pathway by which liposomes pass through the stratum corneum and move down into the epidermis is currently unclear. Also unknown is the proportion of enzymes that actually reach the biopsies.
Despite these gaps in our knowledge, irradiation of human skin with ultraviolet light treated with DNA repair enzymes encapsulated in liposomes has a significant effect of reducing DNA damage compared to controls in clinical studies of several studies, and interested partners can refer to Mr. Yarrosh's article.
04
Related products
Nowadays, many brands have also listed skin care products related to the concept of "light repair", which are mainly divided into two categories:
One is to add relevant ingredients to sunscreen products to achieve better light protection.
Another type of product is the anti-aging series of skin care products, which combine the above ingredients with some existing antioxidant and anti-aging ingredients to achieve better efficacy performance.
Sunscreen
NEOVA RepairIng And Polishing Sunscreen SPF40
NEOVA is an American brand focusing on anti-aging technology, the mechanism design of this sunscreen is what we introduced earlier, adding related ingredients on the basis of ultraviolet blocking and antioxidant resistance, and more effective light protection.
In addition to the combination of physical and chemical sunscreens, ergothioin is added for antioxidant use, as well as micrococcal lysate products and plankton extracts.
IXTIN Zhen Wei Light Protection DNA Repair Water Sense Sunscreen SPF50
Unlike NEOVA's mechanism of efficacy through physical and chemical combination of sunscreens, antioxidants and plankton extracts, this sunscreen of Eastin is a combination of chemical sunscreens, peptides and plankton extracts, with more emphasis on the synergy of tightening anti-wrinkle and DNA repair enzymes.
And because of the use of chemical sunscreens, the skin feeling will be lighter than the combination of physical and chemical sunscreen products.
Skincare
NEOVA DNA Full Repair Serum
True to its name, the core ingredient of NEOVA is DNA repair enzymes.
Unlike other products that add one or a certain type of DNA repair ingredient, this product adds all three types of ingredients to it, micrococcal lysate product + plankton extract + Arabidopsis extract, and compounded with ergothionne to antioxidant.
Murad Mulad White Spot Serum
Murad's Whitening Spot Serum is packed with plankton extract and compounded with other whitening active ingredients.
In terms of the efficacy mechanism of the product, this product does not have the core DNA repair concept that highlights light damage, but we know that the core key to whitening is also inseparable from ultraviolet protection.
Topix SRS Cell Repair Serum
Topix, like NEONA, is a brand that focuses on efficacy. Topix's green tea polyphenol series may be the most familiar products, but his overseas hot sales are actually this cell repair essence.
The serum is also a combination of three types of DNA repair ingredients, while adding evodia to soothe and calm, ergothioin for antioxidant effect.
Today's good thing recommendation is here, in advance of Thursday there is a very interesting skin care topic, we invited internal experts to talk to you about this issue. Before that, please allow us to do a small survey on "skin care product preferences"
bibliography:
[1] Uraiwan Panich, Gunya Sittithumcharee, Natwarath Rathviboon, Siwanon Jirawatnotai, "Ultraviolet Radiation-Induced Skin Aging: The Role of DNA Damage and Oxidative Stress in Epidermal Stem Cell Damage Mediated Skin Aging", Stem Cells International, vol. 2016, Article ID 7370642, 14 pages, 2016. https://doi.org/10.1155/2016/7370642
[2] Schwarz T, Schwarz A. Molecular mechanisms of ultraviolet radiation-induced immunosuppression. Eur J Cell Biol. 2011 Jun-Jul;90(6-7):560-4. doi: 10.1016/j.ejcb.2010.09.011. Epub 2010 Oct 29. PMID: 21035896.
[3] Yarosh DB, Rosenthal A, Moy R. Six critical questions for DNA repair enzymes in skincare products: a review in dialog. Clin Cosmet Investig Dermatol. 2019 Aug 29;12:617-624. doi: 10.2147/CCID.S220741. PMID: 31695467; PMCID: PMC6718248.
[4] Sancar A. DNA repair in humans. Annu Rev Genet. 1995;29:69-105. doi: 10.1146/annurev.ge.29.120195.000441. PMID: 8825469.
[5] Ichihashi M, Ueda M, Budiyanto A, Bito T, Oka M, Fukunaga M, Tsuru K, Horikawa T. UV-induced skin damage. Toxicology. 2003 Jul 15;189(1-2):21-39. doi: 10.1016/s0300-483x(03)00150-1. PMID: 12821280.