With the completion of the sequencing of the Human Genome Project in 2003, the “Human Microbiome Project” was launched at the end of 2007. The number of microbial cells in the human body is 10 times the number of cells in the human body. Preliminary studies have shown that the total number of genes contained in them is 100 times the total number of genes contained in the human genome. People have gradually realized that simply deciphering the genes of the human genome cannot fully grasp the key issues of human diseases and health. The relationship between common basic diseases and mental diseases and the intestinal flora, that is, the importance of the intestinal microecology to the health of the organism has also been reduced. It is widely recognized and put forward the theory system of bacteria-brain-gut axis.
In recent years, the skin microbial flora is one of the main roles of the skin barrier, and the research on it has gradually attracted people’s attention. More and more studies have shown that the balance of microbial flora is an essential factor for maintaining skin health. When the normal skin flora is destroyed, it will cause the skin microecological imbalance, leading to the imbalance of the skin biological barrier, the disorder of the immune mechanism, and the skin function damage and even skin diseases. How to maintain the health of the skin flora and maintain the balance of the skin micro-ecological is an important and popular topic in the current cosmetics industry. This article focuses on the overview of skin microecology and its relationship with skin health, and provides scientific theoretical support for the development of microecological skin care products.
01 Skin micro-ecology
The human skin microecology is the second largest microecosystem after the intestinal microecology. It consists of various microorganisms such as bacteria, fungi, viruses, mites and arthropods, and skin surface tissues, cells, various secretions, and microenvironment. And other common ecosystems. The microorganisms on the skin are collectively called the skin microbiota, which is the basis of skin physiology and immunity. The interaction of skin microorganisms, host and external environment constitutes the skin microecological balance.
1. Skin microbes
The skin is the largest organ of the human body, directly in contact with the external environment, has a unique surface structure and physiological functions. In view of the special surface structure and physiological functions of the skin, the colonization of its microbial flora is very different from the closed environment of the intestines, forming a unique and complex flora structure, which is also affected by the human innate and acquired immune systems , Co-evolve with the human immune system to form a unique ecosystem. Although the skin has relatively low temperature, dryness, high salt, partial acidity, antimicrobial peptides and shedding of dander, etc., it is not conducive to the growth and reproduction of microorganisms, but there are still about 1014 microorganisms on human skin, which is about the total number of human cells. 10 times as much.
The currently known human skin microorganisms include at least 19 phyla. Bacteria are the dominant bacteria on the skin surface. The composition of the bacteria on the skin surface can be analyzed from the following different classification levels: ①At the phylum level, there are mainly Actinomycetes and Thick-walled Bacteria, Proteobacteria, Bacteroides; ②At the genus level, it is mainly composed of Corynebacterium, Staphylococcus and Propionibacterium. In addition, there are a small amount of fungi on the skin. The fungi mainly include Malassezia, Penicillium and Aspergillus. The feet, such as toe nails and plantar heels, show the most abundant fungal flora.
According to the length of time for different microorganisms to colonize the skin surface, they can be divided into temporary flora and permanent flora. ①Temporary flora, which stays on the surface of the skin for a short time, and has less impact on the human body. It is generally the flora that is transmitted to the skin surface when the surface of the skin contacts the surface. The temporary flora is usually the main cause of skin infections. ②The resident flora refers to the long-term colonization of the skin, which has fully adapted to the skin environment and has become dependent, and can be regarded as the core flora of the skin. The resident bacteria on the skin mainly include Staphylococcus, Propionibacterium, Corynebacterium, Acinetobacter, Candida, etc. The resident flora of the skin forms a biological barrier by occupying a place, so that pathogenic bacteria and foreign flora cannot stand on the skin, and have the effect of maintaining balance and self-purification in the skin micro-ecological environment. The resident bacterial flora of the skin is closely related to skin health. It participates in the metabolism of the sebum membrane, maintains the pH of the skin surface to inhibit the growth of pathogenic microorganisms such as fungi; it can decompose horny fines and secrete lipids, so that skin cells can absorb and provide nutrition The role of. The resident flora and the skin’s inherent immune system constitute the body’s barrier against pathogenic microorganisms. These flora together constitute the local microecological environment of the skin, and at the same time there is symbiosis or antagonism between them. If the local environment of the skin and the flora are in a state of inconsistency, that is, the skin microecological imbalance, it will damage the skin health.
2. Factors that affect the skin microecology
The factors that affect the total and composition of the skin microbiota mainly include: ①The area of human skin; ②The chemical properties of the skin, namely pH, fatty acid composition and humidity; ③Gender; ④Geographical location and ethnicity; ⑤Depth of the epidermis; ⑥Antibiotic treatment; ⑦Use of cosmetics; ⑧Personal age; ⑨Personal health status, etc. In summary, these factors can be divided into endogenous factors and exogenous factors.
(1) Endogenous factors
The endogenous factors that affect the total and composition of the skin microbiota mainly include skin age, gender, and different parts of the body, among which age and body parts have a greater influence.
Oh et al. used 16S rRNA sequencing research and found that there are significant differences in the bacterial communities of children and adults in the same part of the skin. Xiong Dexin et al. found that in adolescents, with the increase of age, Staphylococcus epidermidis decreased, while Staphylococcus aureus increased. Gender has the same effect on the skin microbiota. By comparing the diversity of the skin flora of men and women, the bacterial diversity of female hands is significantly higher than that of males, but the number of bacteria in female hands is relatively small.
There are differences in the skin flora of different body parts. The colonization of bacteria is related to the specific wet, dry, and sebaceous gland microenvironment. In general, the bacterial diversity in the sebaceous glands seems to be the lowest. Propionibacterium predominates in the dense areas of the sebaceous glands, as well as in the forehead, back of the ear folds, back and nose folds (side of the nostrils). Metagenomic analysis and culture studies have shown that Staphylococcus and Corynebacteria prefer high-humidity areas, such as the belly button, armpits, groin folds, hip folds, and soles of feet. Staphylococcus bacteria exist in the aerobic area of the skin and reproduce with urea in sweat as a source of nitrogen. Corynebacterium and Staphylococcus aureus play a biological role in the apocrine glands, such as the armpits. In dry skin areas, such as the front, buttocks, hands, etc., the colonized flora includes a mixed flora of Actinomycetes, Proteobacteria, Firmicutes, and Bacteroides.
(2) Exogenous factors
The exogenous factors that affect the skin microecology refer to the external factors in contact with the skin, such as the skin contact environment, the use of cosmetics, and life pressure. A study by an international cosmetics company found that environmental pollution can cause an imbalance of skin microbes and metabolites. Polycyclic aromatic hydrocarbons in pollutants can affect skin metabolism directly or by changing skin microbes. Through the analysis of the psychological stress and skin microbial flora and skin condition of high school students in a certain place, it is found that long-term stress will make the skin microecological imbalance and increase the growth of certain pathogenic bacteria, thereby affecting the skin condition.
At present, cosmetics are in frequent contact with the skin, and the skin micro-ecology is greatly affected by the use of cosmetics. Cosmetic ingredients are both rich in nutrition and contain preservatives that inhibit microbial flora, so the use of cosmetics may change the skin’s microenvironment. In addition, cosmetics can also affect the secretion of sweat glands and sebaceous glands, thereby affecting the skin’s self-purification and metabolic functions. When the skin microenvironment changes, skin microorganisms will also be affected. Therefore, cosmetic ingredients may directly or indirectly affect the skin micro-ecology.
A large number of research results have shown that certain ingredients in cosmetic formulations can interact with microorganisms, thereby affecting the skin micro-ecology. Cosmetics may affect the skin micro-ecology through the following ways: First, the non-pathogenic microorganisms carried by the product itself, these microorganisms modify or change some chemical components in the cosmetics through fermentation or other methods, which can affect the skin’s resident bacteria or skin micro-organisms. The environment has an adverse effect, which in turn causes damage to the skin; the second is that the chemical components in cosmetics can also be metabolized by the skin’s resident flora, thereby producing substances that have an impact on skin health; the third is that the cosmetic ingredients can directly or by changing the skin microenvironment Indirectly affect the colonization of skin microorganisms. The ingredients in cosmetics are complex and contain many chemical substances, such as preservatives, flavors and fragrances, functional ingredients, moisturizers and deodorants, etc. These substances can affect the skin by changing the skin’s microenvironment, such as pH, humidity, and oil content. Micro-ecological balance. Bouslimani et al. studied the effects of skin care products on skin chemistry and microorganisms, and found that skin care products can change the diversity of chemical molecules and bacteria on the skin’s surface, as well as the dynamics and structure of molecules and bacteria.
3. Research methods of skin flora
With the deepening of research on the relationship between flora ecology and skin care efficacy, people have found that some microorganisms are difficult to separate due to harsh growth conditions. The bias and limitations of the traditional method (gel flat method) make it difficult for researchers to correctly and comprehensively clarify the skin. The community structure and diversity of microorganisms. In recent years, the rapid development of microbiome sequencing analysis technology has solved this problem. Microbiome sequencing and analysis technologies mainly include 16S rRNA sequencing and metagenomics technology. The maturity of a new generation of high-throughput sequencing technology has brought tremendous changes to human genomics and microbiome, and the research on skin microecology has also made breakthroughs.
The sequencing of 16S rRNA is the core and most important breakthrough in the field of microbial ecology in recent years. This sequencing technology allows people to obtain more comprehensive community structure information at an acceptable cost. Compared with traditional sequencing methods, 16S rRNA sequencing has obvious advantages: ① It can obtain system classification information, and can identify its taxonomic unit with certainty; ② The throughput is significantly improved, and 400,000 to 1 million sequences can be measured in one time. Obtain extensive and systematic structural information; ③The sequencing depth is large, and quantitative analysis can be performed at multiple classification levels. The establishment of this method has greatly promoted the research of microbiome and made breakthrough progress. For example, this method was used to clarify the composition of the microbial structure of different parts of the human body for the first time, and the influence of the use of antibiotics on the intestinal microbial community.
Metagenomics technology is based on 16S rRNA analysis, through the shotgun method of metagenomics for high-throughput sequencing, so as to obtain the classification information of the bacterial flora and the data of functional genes. Metagenomics technology is suitable for the overall microbial community in a specific environment. It can analyze the structure, species composition and abundance of the microbial community, and can also explore the synergistic relationship between microorganisms and the relationship between the environment and the host. In 2007, the National Institutes of Health used metagenomics to start the study of the human microbiome, collecting and analyzing 242 healthy adult skin microbes. As a result, a database of normal skin microbiota was established. Using this technology, scientists have gradually explored the relationship between changes in the structure of the normal microbial flora of the human body and skin diseases. Fitz-Gibbon et al. used a combination of metagenomics and gene sequencing to compare the skin microbiota of 49 patients with acne and 50 healthy people’s nasal sebaceous glands at the strain level and the gene level. They also analyzed P. acnes. The role of different strains in the pathogenesis of acne. The use of this technology also clarified that the onset of common skin diseases (acne, idiopathic dermatitis, chloasma, psoriasis, etc.) is related to the structural changes and imbalances of the normal skin microbiota.
02 The relationship between microbial flora and skin health
The relationship between the host and the skin microbiota can be divided into four categories: symbiosis, mutual symbiosis, resident pathogenic flora and temporary pathogenic flora. Symbiosis and reciprocal symbiosis belong to skin saprophytic bacteria, which are also normal microbial ecological flora. In general, the effects of signal transmission between the host and the skin symbiotic microorganisms are two-way.
1. The effect of skin on the homeostasis of microbial flora
The composition of skin microbiota is not random, and is regulated to some extent by skin physiology. First, keratinocytes gradually migrate from the basal layer to the stratum corneum during the differentiation of the epidermis, and eventually lose organelles, keratinize and slough off, and keratinocyte residues after shedding and disintegration, such as protein, phospholipids, amino acids, glucose, water and Electrolytes (such as potassium, sodium, and calcium) provide nutrients for the growth of skin flora and are conducive to the survival of skin microorganisms.
The sebum secreted by the sebaceous glands can be used as food for the microbial flora. After the sebum is decomposed, free fatty acids are produced and an acidic environment is generated to maintain the growth of the microbial flora. The sweat excreted by the skin contains salt and electrolytes. After the sweat evaporates, the surface of the skin is slightly acidic with electrolytes. This environment restricts the reproduction and survival of pathogenic bacteria. In addition, the eccrine glands on the skin express antimicrobial peptides (AMP), including endocrine antibiotics and β-defensins, to affect the colonization of skin microorganisms, that is, where the sweat glands are denser, the survival of microorganisms is relatively small.
Inside the skin, both innate and adaptive mechanisms contribute to skin immunity. Keratinocytes are the first active participants in the skin immune response. The cells express a large number of pattern recognition receptors (PRR), which can recognize conservative molecules, such as lipoproteins, nucleic acids, cell wall components and flagella, to perceive external microorganisms; expression Many antibacterial peptides, cytokines and chemokines, and activation of PRR, can rapidly increase the expression of these molecules, thereby producing direct antibacterial effects and additional immune cells. Langerhans cells in the epidermis can present antigens. Studies have shown that Langerhans cells participate in promoting the tolerance of self-antigens and symbiotic microorganisms by inducing regulatory T cells in a stable state. Inside the skin epidermis, there are many cells involved in innate immunity and adaptive immunity, such as dendritic cells, macrophages, mast cells, natural killer cells and various T cells.
In short, the skin surface environment and internal cellular immune system are of great significance to the growth, homeostasis, and specialization of the microbial flora. 2. The effect of microbial flora on skin health
The skin microbial flora protects the body in the following two ways: one is to prevent and inhibit the invasion of pathogens and to stimulate the production of antibodies to improve the immune status of the host; the other is to synthesize vitamins, especially vitamin K and several B vitamins. , Provide nutrition for the skin. However, the resident flora will not always play a good role. When the immunity is reduced, the resident flora can also cause disease. If they multiply in abnormal areas, they may also become pathogens. For example, Propionibacterium acnes can cause acne to occur and develop.
(1) Inhibit the growth and development of pathogenic microorganisms
Skin symbiotic microorganisms can inhibit the colonization of pathogenic microorganisms in the skin through direct and indirect methods, so as to avoid damage to skin health. In competitive rejection, skin resident bacteria compete with pathogenic microorganisms for receptors or binding sites on host cells, so that pathogenic bacteria cannot reproduce. Staphylococcus epidermidis on the skin can produce serine protease (ESP) to inhibit the formation of Staphylococcus aureus biofilm. Staphylococcus epidermidis can also produce a variety of additional molecules that affect the growth of pathogenic microorganisms. For example, the phenol-soluble modulator (PSM) produced by Staphylococcus epidermidis has a strong antibacterial function and can interact strongly with microbial lipid membranes and lead to microbial lipids. Leakage of membrane. The molecules produced by Staphylococcus epidermidis can also selectively kill the skin pathogens Streptococcus pyogenes and Staphylococcus aureus, and can produce stronger bactericidal ability in cooperation with host-derived AMPs. In addition, the resident flora can reduce the pH of the skin and maintain the acidic environment of the skin to a pH of 3.0 to 5.0, thereby inhibiting the growth of pathogenic microorganisms.
(2) Stimulate skin cells to produce immunity
Skin symbiotic microorganisms can promote skin immunity by affecting the function of host cells. The abundant microorganisms on the skin surface can interact with the skin’s epidermal keratinocytes and immune cells, affect the local and systemic immune responses of the skin, and participate in the establishment of immune homeostasis. The skin flora can also affect the immune function of the skin by regulating the interleukin I (IL-la) in the skin.
There are many types of mechanisms that promote skin immunity by influencing host cells. James and other studies have shown that keratinocytes sense Staphylococcus epidermidis through Toll-like receptor 2 (TLR2), and then increase the expression of antimicrobial peptides such as B-defensin 2 and defensin 3 to enhance the host’s immunity to Staphylococcus aureus infection force. This indicates that signals from skin symbiotic microorganisms lead to increased expression of antimicrobial peptides in keratinocytes through TLR2 and block the activation of NF-KB induced by pathogenic Staphylococcus aureus. The influence of skin symbiotic microorganisms can also extend to other types of cells. Studies have shown that under the mediation of Staphylococcus epidermidis, TLR2 is activated, which leads to the accumulation of mast cells to the site where skin viruses attack. The AMP aspartic acid released by these aggregated mast cells is stimulated and amplified by TLR2, thereby enhancing antiviral resistance. immunity. Therefore, signals from symbiotic microorganisms are related to multiple cell types that respond to various microbial challenges in the skin.
In short, symbiotic bacteria play an important role in enhancing the host’s immune defense against pathogens.
(3) Control inflammation and maintain skin barrier
Skin symbiotic microorganisms can promote host immunity by maintaining the skin barrier. For example, the recognition of lipoteichoic acid (ITA) by Staphylococcus epidermidis mediated by TLR2 can inhibit the production of inflammatory cytokines driven by TLR3 in keratinocytes and reduce the level of inflammation in the body after trauma. In addition, the activation of TLR2 has been shown to increase the tight junction barrier of keratinocytes, indicating that symbiotic microorganisms also play a role in maintaining the dynamic balance of the barrier.
Microorganisms indirectly shape the microbe-host immune homeostasis by metabolizing skin proteins and lipids and other components to produce bioactive molecules. Studies have shown that there is a mutually beneficial relationship between Staphylococcus epidermidis and keratinocyte inflammation. The LTA produced by Staphylococcus epidermidis binds to the innate immune receptor TLR2 to inhibit inflammation during skin injury. Qiu Zhuoqiong et al. found that skin symbiotic bacteria can metabolize tryptophan to produce 5-hydroxytryptophan, indole-3-acetaldehyde, etc., and found that indole-3-acetaldehyde activates the aromatic hydrocarbon receptors of epidermal keratinocytes. Inhibit the production of thymic stromal lymphopoietin, thereby reducing the degree of inflammation of atopic dermatitis (AD). The communication between skin symbiotic microorganisms and skin cells is very important for regulating the local inflammatory environment.
(4) Nutritional effect
Degrade the surface material of the skin and provide nutrition.
There are many biological macromolecular substances on the surface of the skin, such as a mixture of lipopolysaccharides and proteins, and various components. The microbial flora living on the skin can degrade the surface substances of the skin as food. The disintegration products after the death of microorganisms contain extracellular enzymes such as lipase, esterase, protease, keratinase, phosphatase and DNase. These extracellular enzymes can degrade these macromolecular polymers and release small molecules that can be easily used. Molecular nutrients. For example, esterase can act on triglycerides and degrade them into glycerol and free fatty acids; protease can degrade protein molecules and polypeptides into small peptides and amino acids; phosphatase can act on substrates to phosphorylate organic molecules and decompose them It is dephosphorylated sugars and phosphates; DNA enzymes can degrade DNA into sugars, phosphates, purines and pyrimidines. Almost all the end products of extracellular enzymes can be absorbed by the skin and have a direct nutritional effect on the skin.
Synthesize life substances to provide nutrition.
In addition to the decomposition products of extracellular enzymes, bacteria can also produce a lot of vitamins, such as vitamin A, B1, B2, B5, 86, B7, B9, B12, E and vitamin K, acetate, butyrate and propionic acid compounds, nerves Transmitters (such as serotonin), etc., provide nutrition for the skin. The phospholipids, sterols and keratins produced by the skin microbial flora can also be absorbed by skin cells to enhance cell growth. The electrolytes and small-molecule proteins produced by the skin microbial flora have moisturizing properties, so that the skin has the ability to retain water.
(5) Harmful effects
Generally, the skin flora will not fluctuate greatly under the action of the skin and symbiotic microorganisms, nor will it cause skin diseases. However, under certain environmental changes, a part of the normal flora may cause diseases. If introduced into the blood or tissues from the restriction of the environment, it may become a pathogen. Bacteroides bacteria are the most common resident bacteria. If they are introduced into the free peritoneal cavity or pelvic tissue together with other bacteria due to trauma, it will cause suppuration and bacteremia. This shows that the presence of resident bacteria in normal skin areas is harmless, but if a large number of temporary bacteria are introduced or there are other predisposing factors, they may also cause diseases.
03 Micro-ecological disorders and skin health
The normal skin microbiota and the host form an interdependent relationship. They form a harmonious and balanced ecology and play an important role in maintaining the physiological functions of the skin. Once this balanced ecology is disturbed, it will cause certain skin problems, such as dryness, itching, etc.; when it is more serious, it will cause external pathogens to invade or the normal skin microbial flora to turn to pathogenic bacteria, leading to infectious diseases.
Studies have found that facial microbiota disorders can irritate the skin and cause inflammation, leading to skin problems such as pigmentation and aging. If the skin Staphylococcus aureus invades and occupies the skin surface, the amount of antimicrobial peptides produced will be insufficient, which will cause allergic dermatitis, leading to itching, dryness and tingling of the skin; the instability of the aerobic flora of the hands is conducive to pathogenic bacteria Propagation, which in turn leads to dry skin. Allergens and microorganisms are more easily invaded, which can weaken the skin barrier and inhibit the innate host defense system. The imbalance of skin microbiota is often related to several immune-mediated diseases, such as acne, psoriasis, and atopic dermatitis. Therefore, studying the changes in the microbial community throughout the skin is the key to understanding skin diseases.
Among the skin microbial flora, the flora most closely related to the occurrence of acne includes Propionibacterium acnes, Pityrosporum, Staphylococcus and so on. The effect of P. acnes on acne is mainly reflected in the following two aspects: ① triggering an inflammatory response; ② triggering hyperkeratosis of the funnel of the hair follicle. Pityrosporum is also known as Malassezia furfur. A specific form of Malassezia can cause folliculitis, often combined with acne. Some scholars have shown that 83.57% of the pityrosporum carrying rate was detected in the skin samples of acne patients, and it was found that the severity of acne was positively correlated with the number of pityrosporum carrying bacteria. Increased sebum secretion in patients with acne leads to excessive reproduction of Pityrosporum sp. causing local inflammation.
2. Atopic Dermatitis
Studies in recent years have confirmed that the reduction of skin microbial diversity may be the predisposing factor of atopic dermatitis (hereinafter referred to as “AD”). German scholars have carried out a study of 2500 infants. The results of the study show that infants delivered by caesarean section have fewer microorganisms detected on the skin surface than infants delivered naturally through the birth canal (indicating that the diversity of skin microorganisms is reduced). The risk of atopic diseases is significantly increased. Current studies have shown that Staphylococcus aureus colonization and infection are often associated with the onset of AD. During the onset of AD, the detection rate of Staphylococcus aureus was significantly higher than that of healthy skin or AD patients after treatment, and it was found that the detection rate was closely related to the severity of the disease. The abundance of Streptococcus, Corynebacterium, and Propionibacterium in the inflammatory lesion area of AD patients decreased, while the abundance of Staphylococcus aureus increased. After treatment, the abundance of Streptococcus, Corynebacterium, and Propionibacterium increased.
Various studies have shown that the balance of skin microbial ecology is achieved by the continuous interaction between skin microbial communities, skin microbes and the host. The imbalance of the skin microecological ecology can cause a variety of skin problems and affect skin health. Therefore, maintaining the skin microecological balance is very important to maintaining skin health, and has received widespread attention from researchers in dermatology and skin care industries in recent years. At present, in the field of skin care products, micro-ecological skin care has become the latest product development trend.
04Micro-ecological skin care and health
1. Micro-ecological skin care has become a hot spot
Mintel Trends described in the report “Total Wellbeing” (Total Wellbeing) how consumers view their bodies as an ecosystem and look for solutions to meet personal health and changing needs. Therefore, consumers are becoming more and more interested in the skin microecology, which has stimulated the demand for products that balance the natural flora inside and outside the body-the development of intestinal probiotics into probiotic skin care products. According to Mintel’s “Facial Skin Care-China” (August 2019) report, 95% of consumers have heard of skin care products containing probiotic ingredients, and 55% of them have even bought skin care products containing this ingredient. Product. In the past five years, the number of products listed on the global market claiming “probiotics” has increased by about 260%, and micro-ecological skin care has become a new form of skin care.
With the development of biotechnology, the popularity of micro-ecological skin care has continued to rise in recent years. In 2019, L’Oréal concentrated on the field of micro-ecological skin care. Its Lancome, La Roche-Posay and Helena have launched micro-ecological skin care products. Lancome’s second-generation small black bottle claims to use the essence of prebiotics and yeast to continuously activate the skin micro-ecology, which can be said to be a typical representative of micro-ecological skin care. Estee Lauder and SK-ll have launched “micro-ecological skin care” products through concepts such as probiotics and prebiotics. Domestic brands have also entered the micro-ecological market. Dr. Yuaner and Proya have launched their own products, and the market has performed well.
The brand of Dr. Yuaner under Freda adds prebiotics and probiotics such as inulin to the star product probiotic water emulsion. After the test of the population and the analysis of changes in the skin microbial flora, it is found that it can balance the microecological bacteria brought by staying up late. Group changes to improve skin problems caused by staying up late.
The imbalance of the skin micro-ecological environment is the root cause of sub-healthy skin. B rigitte Dreno et al. found that severe acne was not caused by the proliferation of Acne propionic acid but the diversity of Acne propionic acid (IAI, CC18, A1) decreased, and pointed out that it should be improved by adjusting the balance of skin flora Acne. Ecological skin care, that is, maintaining the micro-ecological balance of the skin, is the use of micro-ecological engineering technology to apply probiotic-related preparations to daily skin care. This kind of ecological preparation can adjust the human skin microecological balance, adjust and restore the skin imbalance caused by internal and external factors, promote the production of various enzymes and beneficial substances in the skin, and then regulate the epidermal cells, maintain the skin’s moisture and nutrient absorption, and maintain Skin health status. Therefore, the use of probiotics or prebiotics to regulate the skin micro-ecological balance and fundamentally improve the sub-healthy skin of ecological skin care products will be the focus of skin care product research and development, and it is also the development trend of the skin care industry.
2. Current micro-ecological skin care methods
The current micro-ecological skin care is mainly achieved in the following three ways:
(1) Probiotics for external use
Probiotics are living bacteria that can provide benefits to the host, such as bifidobacteria, lactobacilli, and vitreoscilla filaments. The concept is derived from intestinal probiotics. Clinical studies have shown that external use of probiotics can improve skin health by affecting the composition of the skin microbiome. Nodake et al. isolated Staphylococcus epidermidis from the autologous skin of subjects, cultured and added it to the basic cosmetic formulations to improve the moisturizing properties of the skin after use. Although studies have proved that the direct application of skin resident live bacteria preparations has the effect of skin care, but because there is no corresponding evaluation system and restricted by laws and regulations, such products need further research. There are also a small number of inactivated probiotics in the industry. For example, SymReboot TM L19 is an inactive Lactobacillus, but it has a complete cell structure and can provide all the functions of living bacteria. It can regulate the skin microflora and strengthen the skin. The barrier and other effects. La-Flora EC-12 from Ichimaru, Japan is an inactivated (heated) lactic acid bacteria in a powder state, which can promote the proliferation of Staphylococcus epidermidis on the skin surface and promote the production of antimicrobial peptides.
(2) Prebiotics for external use
Prebiotics are specific nutrients (such as lactose, oligosaccharides, dextran, sorbitol, xylitol, etc.) that can be absorbed by symbiotic bacteria. Prebiotics can promote the reproduction and growth of symbiotic bacteria, which is beneficial to the health of the host’s skin. In micro-ecological skin care products, there are relatively more developments and applications of prebiotic-related raw materials. For example, DSM’s [email protected] is a carbohydrate isomer that promotes its ability to improve the diversity of skin flora, thereby improving the skin barrier. FLORASKIN L (inulin, dextran oligosaccharides) from France Xianting Company is a prebiotic raw material used in cosmetics. Experiments have shown that it can be used by beneficial skin bacteria and will not be used by harmful bacteria. Through competitive inhibition of nutrition , To achieve the purpose of maintaining the structure of the skin flora, increase the immune function of the skin, thereby improving the skin condition.
(3) Postbiotics for external use
Epibiotics, also known as prebiotics, are metabolites produced by probiotics or a class of compounds produced by probiotics that have direct or indirect effects on the host, including probiotic bacterial fragments, secreted metabolites, extracts and solvents. Cell products and so on. Studies have shown that adding 1% linear Vitreoscilla lysate to cosmetic creams can alleviate the symptoms of dry and sensitive skin and increase the skin oil and moisture content of sensitive skin. CLR’s ProRenew Complex CLRTM is a fermentation lysate derived from lactic acid bacteria, which can balance and protect the skin microbiota and maintain the skin barrier. In addition to simple probiotic lysates and fermentation products, there is also a type of probiotic fermentation raw materials, that is, the use of probiotic metabolism and enzyme systems for the fermentation of functional raw materials to obtain functional ingredients with small molecular weight and good osmotic absorption. For example, Aotingmin (lactobacillus/soymilk fermentation product filtrate) of Xianting Company is the fermentation filtrate obtained after fermenting soymilk with lactic acid bacteria. It contains protein, amino acids, organic acids, vitamins and other substances, which can improve the surface of the skin. The diversity of beneficial bacteria strains increases the abundance of Staphylococcus epidermidis, maintains a weakly acidic environment for skin health, and improves skin hydration.
3. The future of micro-ecological skin care
Micro-ecological skin care is undoubtedly another important field in the development of the cosmetics industry. However, micro-ecological skin care is still in the enlightenment and initial stage of development. The concept of micro-ecological skin care, research on raw materials and products, evaluation methods, regulations and market supervision still need to continue. perfect.
Because micro-ecological skin care brings real benefits to consumers, in recent years, many domestic and foreign brands have made efforts in this field and achieved remarkable results. With the development of micro-ecological skin care, it will be developed in terms of concept, research and development, consumer education, and sound laws and regulations.
In 2020, Freda Beauty and Dr. Aier jointly organized the “Skin Microecology·The First Beauty & Dermatologist Cross-Border Conference” in the joint Jumei and CSDCMA Dermatology News. In this conference, Freda Beauty is the first The concept of micro-ecological skin care is put forward, and micro-ecological skin care is conceptually divided into narrow and broad micro-ecological skin care: ① The narrow-sense concept of micro-ecological skin care refers to the use of raw materials from microbial sources, such as lysates, cytosols and prebiotics. Used as a functional raw material in skin care products to improve skin health. ② The broad concept of micro-ecological skin care is based on the concept of micro-ecological skin care in the narrow sense, so that the product formula structure can maintain the skin micro-ecological balance, or not harm the skin micro-ecological balance to the greatest extent.
In terms of regulations and market supervision, international brands and related research institutions have successively held meetings to discuss and look forward to the supervision and management model of micro-ecological skin care. In the future, the establishment of quality standards for related cosmetics, the popularization of microbiological testing methods, and the research and popularization of the relationship between effects and action mechanisms will be developed.
In any case, maintaining the skin’s micro-ecological balance and promoting skin health is an established direction of the efforts of cosmetic researchers!