Filagrinol
Optimizing epidermal function through a proprietary filaggrin modulator
Many attempts have been made to modify the appearance of the skin on the assumption that it is biologically inert, dead and impenetrable. The research engaged over recent years, some of which is extremely relevant, demonstrates, at the specific epidermal level, living activity and organic reactivity we usually find in tissues with a higher metabolic turnover.
Filaggrin (FILament AGGregating proteIN), the so-called histidine-rich protein found in human epidermis, as described by Steinert and coll. in 1981, has a peculiar function in promoting keratin filaments aggregation thus forming compact microfibrils.
As a result of a later stage of degradation, filaggrin is largely responsible for the formation of a pool of low MW, water-soluble molecules (amino acids and their derivatives) which play a role in the stratum corneum: particularly in maintaining the right level of hydration and thus flexibility.
That filaggrin plays the main, if not the sole, source of the stratum corneum free amino acids (referred also as Natural Moisturising Factor) comes from the excellent qualitative and quantitative correlation between the amino acid composition of this pool and that of filaggrin.
The main interesting aspects of filaggrin for cosmetic applications are:
- a fair availability of filaggrin as the biochemical base for a complete aggregation of keratin filaments, which could mean highly efficiency in cornified barrier;
- its function of generating in situ a pool of amino acids and their derivatives which guarantee the flexibility and integrity of the epidermal barrier, by assuring the right degree of hydration.
The topical application of cosmetics containing Vevy Europe's Filagrinol, a proprietary natural-derived ingredient, allows a correct performance of filaggrin metabolism which finally leads to an increase in skin resiliency and moisturization, a functional protection of the dermis, an effective activity on fine lines and other signs of aging.
Safety of Filagrinol has been fully determined according to Vevy Europe Toxicological Protocols for Dermo & Cosmetic Grade Assurance, while its efficacy has been assessed by histochemical, immunoistochemical, clinical and in vitro testing.
1. Histochemical reaction marking bound histidine
The method stains the stratum granulosum determining a thin orange strip. Colour intensity is proportional to filaggrin percentage. The sulfanilic acid used in this method does bind with histidine only when histidine is in a protein chain, while other precautions have been taken to avoid positive reactions due to other molecules (e.g. tyrosine).
2. Immunoistochemical identification
The used immunoistochemical method is similar to Dale's and employs an antibody produced by test animals injected with the substance we are looking for. The antibody having a strong affinity chemically binds filaggrin through hydrogen bonds.
The immunohistochemical method stains only filaggrin (and its 400 KD polymeric precursor, profilaggrin) in a brown colour. The remaining areas are blue stained by hematoxylin.
3. Clinical evaluation
Clinical double-blind evaluation on man by using an O/W emulsion containing 8% Filagrinol vs. placebo. A double evaluation was performed:
- skin moisturization was evaluated by an instrument, according to Masuda, able to measure skin resistance and capacitance;
- dermatological subjective evaluation of hydration, texture and smoothness;
4. Protection against lipoperoxidation
Filagrinol protection against UV rays-induced lipoperoxidation was performed evaluating in vitro the single application of an O/W emulsion containing 8% Filagrinol and the 10-days application of the same cream.
According to the reported results we may conclude that Filagrinol modulates filaggrin production in the epidermis and results in a powerful moisturizer effective against skin aging.
We must remember that epidermal cells (during their differentiation into keratinocytes) form a rigid protein sheath around from the crosslinks caused by transglutaminase. Inside the cells, keratin fibers show a rigid but elastic structure able to maintain the flat shape of these cells. Filaggrin breakdown generates a great quantity of low MW water-soluble molecules causing in the deeper part of the stratum corneum, still rich in water, a high osmotic pressure which asks for solvent, i.e. water, inside the stratum corneum cell.
We may postulate that such a pressure brings to tensional forces transmitting from cell to cell through intercellular junctions thus playing a significant role in skin resiliency. Indeed resiliency is reduced in the most superficial layers as water content decreases.
The need for a continuous presence of filaggrin and its derivatives is even more evident if we consider the high concentration of oxygen free radicals. Biomembrane lipid peroxidation promoted by these free radicals creates a series of reactive aldehydes, capable to form crosslinks and therefore less easy to moisturize molecular aggregates. Being Filagrinol effective against lipidic peroxidation, consequently its performance is obtained both by modulating filaggrin production and by an anti-lipoperoxidation, i.e. antiaging, activity.