The cutaneous barriers strengthening for a global care
SUMMARY:
The term “barrier“ is often used to characterize either the global function of skin or to focus on the stratum corneum physico-chemical properties. Nevertheless, it must be extended to a whole of dynamic cutaneous barriers whose main role serves the skin homeostasis and brings a daily protection. This article highlights how active ingredients act on the different skin barriers while combining protection and well-being under the global strategy.
Many years ago, skin was thought to be biologically inert. Recently, our views have been developing in the exact opposite direction! The skin is the largest organ of our body. It plays a fundamental role in our external defense against aggressive factors that daily affect its homeostasis and integrity. Homeostasis (from the Greek “Homoios” and “stasis”, meaning the same state) of the skin refers to its own ability to maintain its internal environment despite external changes. Composed of several layers, commonly referred to as layers, the skin provides a series of connected dynamic barriers to keep it protected and in good condition.
The term “barrier” is often used to characterize the main function of the skin, or to emphasize the physical and chemical properties >stratum corneum. The skin, on the other hand, consists of 4 barriers that constantly maintain complex cellular and extracellular connections: the microbiological barrier, the chemical barrier, the physical barrier, the immunobiological barrier between the epidermis, dermis and hypodermis. (Fig. 1)
Fig. 1: Skin barriers
Our body is a complex ecosystem in constant interaction with the environment. It is colonized by a large number of microorganisms that coexist in very diverse environments. These microorganisms provide protection and play a role in many physiological phenomena. Many endogenous and exogenous (including handwashing, antiseptic) disturbances can affect the relationship between the host and the microorganism, which can lead to imbalance. Therefore, it is necessary to ensure the balance of the microbiota, the safety of our body, well-being and health.
The microbiome’s commensal bacteria control the growth of pathogenic bacteria through competitive inhibition by occupying bacterial anchorage sites on the skin. In addition, these skin ecosystem savers work by producing enzymes, antimicrobial peptides, and natural antibiotics (lantibiotics), which are produced by some bacteria of the Actinobacteria phylum.
Fig. 2: Metagenomic results
Among the active ingredients for maintaining microbial diversity and the ecosystem, prebiotics are ingredients that selectively feed existing healthy bacteria to help maintain microbiome diversity and prevent colonization by pathogens.</span >
Prebiotics can be made using innovative high-tech biocatalysis. This applies to α-glucanoligosaccharides obtained as a result of enzymatic synthesis from a plant substrate and characterized by high selectivity. Its structure ensures better and faster metabolism by the microbiome and thus prevents dysbiosis phenomena. Moreover, some ex-vivo studies have identified the ability of α-glucanoligosaccharide to enhance skin defenses by stimulating the release of the antimicrobial peptides β-defensin 2 and 3. With recent advances in gene sequencing assays such as bacterial 16S ribosomal RNA, a preliminary in vivo study was conducted to better understand how α-glucanoligosaccharides rebalance the bacterial flora and thus enhance the microbiological barrier of the skin. It has been shown that at 3% they increase the proportion of actinobacteria and firmicutes by 21% and 36%, respectively, after 15 days of application. There is also a strong increase in the population of Staphylococcus epidermidis by 146%. As part of the Firmicute family, the latter inhibits the spread of Staphylococcus aureus by activating keratinocyte signaling pathways to initiate the production of antimicrobial peptides and pro-inflammatory cytokines. (Fig. 2)
Combining the properties of the skin microbiome with the physical and chemical barriers of the skin is now universally recognized to preserve, strengthen and, if necessary, walking, restoring healthy skin. Indeed, if it remains intact, the stratum corneum provides a strong protective barrier to the penetration of microorganisms into the skin.
The physical barrier or stratum corneum is compared to a brick wall structure (corneocytes) held together by a lipid film located in the intercorneocyte layers as cement mortar. This organization ensures the integrity of the skin, maintaining its homeostasis, which is associated with a decrease in skin dehydration and optimal protection from environmental influences, including pollution.</ p>
Among the various lipids that make up the intercorneocyte space and act as a bonding cement, ceramides, in combination with free fatty acids and cholesterol, are approximately equimolar concentration form an ordered structure. Ceramides are sphingolipids linked to fatty acids by an amide bond. They reduce skin dehydration and the penetration of aggressive environmental factors such as pollutants and therefore the risk of skin sensitization and discomfort.
There are 12 different classes of ceramides in our skin. Non-hydroxylated ceramides, known as “N”, are the most abundant in the stratum corneum. Among them, ceramides 3 [NP] account for approximately 22% of the total ceramides. In atopic skin, it has been shown that a decrease in their number significantly correlates with a change in transepidermal water loss.
To optimize the strength of the physical barrier, a combination of ceramide 3 with a ceramide analog, whose structure is close to ceramide 10 [NdS] and 2 [NS], was obtained. This ceramide analogue (Safflower oil/Palm oil aminopropanediol esters) was obtained by a solvent-free enzymatic synthesis. (Figure 3) It is composed of stabilized linoleic acid (from safflower oil, where its concentration exceeds 70%), an essential polyunsaturated fatty acid known for its ability to enhance skin barrier function and regulate skin inflammation. This ceramide complex acts to seal the intercorneocytic space and stimulate the synthesis of sphingomyelin, a metabolic pathway precursor for ceramides such as ceramide 2 and 5. (Figure 4)
Fig. 3: Ceramide complex
Fig. 4: Sphingomyelin stimulation
In recent years, consumers have become more aware of the dangers of pollution than ever before, and the fight against pollution has become an increasing problem for their daily skin care. Pollution is identified as a daily hazard whose harmful effects on skin and health are not long in coming.
Pollution control can be achieved by two main strategies that can be combined. The first involves applying a protective film, such as biotechnological polysaccharides, to the skin (and hair) and then removing contaminants. The second focuses on limiting biological responses and strengthening skin barriers, for example through the use of fucoidans, sulfated polysaccharides isolated from Ascophyllum nodosum. Among other proven properties related to the protection and stimulation of immunobiological barriers (structural protection against pollution, improvement of skin firmness, prevention and correction of skin redness and dark spots), fucoidans increase the physical skin barrier at 2% administration, reducing TEWL and enhancing skin hydration.
Age-related sagging of facial skin is added to the undesirable manifestations of aging and is the result of morphological changes in skin structures, especially at the level of the hypodermis. The deepest layer of the skin is affected by the decrease in subcutaneous adipose tissue associated with adipocyte atrophy, along with a decrease in the accumulation of new lipids. All these phenomena lead to the manifestations of aging and affect mainly the contours of the face or the V-zone, as well as the eyes and neck, which define the Y-zone. Beyond the hypode Rhymes, age-related skin damage and structural changes also refer to the immunobiological barrier, weakened by a violation of cellular communication and metabolism. So how to deal with the imbalance of skin volume with loss of elasticity and restore harmony?
Nicknamed the fruit of eternal youth and referred to as red diamonds, goji berries (Lycium barbarum) are superfruits well known for their numerous health and beauty benefits. In particular, the goji berry extract, obtained through environmentally responsible supercritical water extraction technology, has shown many biological properties to overcome skin transformation. It counteracts the signs of aging due to its ability, on the one hand, to regulate age-related micro-inflammatory phenomena that disrupt adipogenesis, and, on the other hand, to stimulate the production of new intracellular lipids due to its lipofilling action.
In addition, goji berry extract supports the papillary dermis barrier and elasticity (2% ex vivo study compared to placebo, on skin explant showed a significant increase of 26% in chondroitin sulfate synthesis), strengthened the dermal-epidermal junction (significant increase in laminin-5 levels compared with placebo) and increased interactions between the epidermal matrix and cells and intercellular interactions (significant increase in vinculin compared with placebo) .
Additional results highlight the ability of goji berry extract to harmonize V- and Y-zones, eliminating signs of skin aging. First, it helps reshape facial contours and limits sagging, visibly improving the V-zone after 56 days. (Fig. 5) It also balances the volume of the Y-zone in the tear trough and bags under the eyes for a more even and rejuvenated eye contour. (Fig. 6)
Fig. 5: Remodeling of facial contours / sagging skin
Fig. 6: Lifting of the lacrimal trough and bags under the eyes
Conclusion
Health and beauty combined with protection and well-being are now the top needs we see in cosmetics today. Strengthening skin barriers plays a fundamental role in achieving this. Balancing the biodiversity of the microbiome (BIOECOLIA®), strengthening intercorneocyte spaces to preserve the integrity of the skin on the outside (CERALINK + ®), fighting against pollution (Invincity® Powder) and finally harmonizing the contours and volumes of the face, against negative wrinkles and improving aesthetics (REVYSKIN®) – here are the additional actions that natural active ingredients can give in the formulation.
Natalia Novikova, Technical and Consulting Support Specialist, Revada LLC
Hanani Selin, Product Development Manager,Solabia Group
Jean-Francois Molina, Marketer, Solabia Group
