EP1648479A2

EP1648479A2 - Therapeutic use of lipids extracted from mother of pearl

Info

Publication number: EP1648479A2
Application number: EP04767391A
Authority: EP
Inventors: Evelyne Lopez; Elian Lati; Bernard Djian
Original assignee: D'innovation Et De Recherche Appliquee Sa (siera Sa) Ste
Current assignee: D'innovation Et De Recherche Appliquee Sa (siera Sa) Ste
Priority date: 2003-06-20
Filing date: 2004-06-18
Publication date: 2006-04-26
Also published as: FR2856303A1; US20070098809A1; WO2004112808A2; FR2856303B1; WO2004112808A3

Abstract

The invention relates to the use of lipids extracted from the mother of pearl of mother-of-pearl molluscs, as a medicament, especially in pathologies and traumas relating to a decrease in filaggrin activity and/or an increase in membrane transglutaminase activity. The invention also relates to pharmaceutical compositions containing said lipids.

Description

THERAPEUTIC USE OF LIPIDS EXTRACTED FROM NACRE

The present invention relates to the use of lipids extracted from mother-of-pearl from a mother-of-pearl mollusc as a medicament, in particular in pathologies and traumas linked to a decrease in the activity of filaggrin and / or an increase in the activity of membrane transglutaminase. It also relates to pharmaceutical compositions containing them.

Psoriasis is a chronic inflammatory dermatological disorder which currently affects more than 2 million people in France and 3 to 5% of the European population. With nearly 60,000 new cases each year in France, it is one of the most frequent dermatological conditions. Although its causes are still imperfectly known, it is considered today as an autoimmune disease with genetic and environmental factors.

This disease is manifested by red patches which are covered with thick white scales. It can affect the elbows, knees, lower back, scalp, feet, nails or folds. In the most severe cases, psoriasis can affect the ears or face, or even the whole body. Most of the time harmless, these conditions have the disadvantage of being unsightly. Although the disease is not contagious, the 3% of the affected population suffers from a host of prejudices. In about 8% of cases, psoriasis appears as a serious disease because it spreads all over the body or is accompanied by serious complications, particularly rheumatic.

Psoriasis is characterized by (1) epidermal hyperproliferation (excessive growth with incomplete and accelerated differentiation) and (2) inflammation of the epidermis and dermis visible locally. Today, it is argued that this disease is caused and / or developed by the activation of specific T cells antigens, autoimmune reactions, and a proliferation of mediating factors that would induce the proliferation of keratinocytes. Thus, the expression phase of the disease is characterized by (1) activation of T lymphocytes in particular due to interferon γ, (2) activation of epidermal cells (keratinocytes secrete inflammatory cytokines, such as IL1, TNFα , and IL8, and chemokines), and (3) the recruitment of endothelial cells, in particular those of the venous capillary network, causing vasodilation and interaction with circulating white blood cells. The keratinocytes divide too quickly according to a disordered keratinization sequence which results in hyperproliferation of the epidermal layers and thickening of the epidermis. This results in hyperkeratosis or in a thickening of the stratum corneum which becomes dry and flaky.

Thus, given these multiple mechanisms, various treatments are currently available and commonly used to treat patients with psoriasis, including a variety of treatments by topical route, by phototherapy, and by oral route. Topical treatments include steroids, tar, anthralin, vitamin D3 and the like, retinoids, and UV radiation. Side effects associated with the use of topical treatment include thickening of the skin, the appearance of dark spots, burning, irritation and photosensitivity. The use of steroids can also lead to some resistance, making subsequent steroid treatments ineffective. Phototherapy includes treatment followed medically with type B ultraviolet radiation (UV-B) or treatment with psoralen in combination with UV-A. Long-term use of phototherapy can age skin prematurely and increase the risk of skin cancer. Oral treatments, generally used for the most serious cases, include the administration of methotrexate, oral retinoids, or cyclosporine. The use of methotrexate requires important medical follow-up to avoid any damage to the liver. The use of oral retinoids should be controlled in women because of their teratogenic effects. Cyclosporine, a immunosuppressant, is reserved for patients who have not responded to other oral treatments or for whom other treatments are contraindicated. The alternation of these treatments, possibly in combination with phototherapy, has also been found to be effective in some cases.

To date, there is therefore no completely satisfactory treatment and all patients do not respond to or tolerate the therapies currently available. New alternatives to psoriasis treatments are therefore being sought, in particular to improve their effectiveness and / or to reduce side effects. Finally, better use of existing drugs in combination with new treatments could lead to significant improvements.

Filaggrin is a protein located in the outermost layers of the epidermis. Profilaggrin, a protein rich in histidine, is the main component of the keratohyaline grains of the stratum granulosum. During terminal differentiation, profilaggrin is dephosphorylated then partially proteolysed into intermediate compounds, then into filaggrin. Filaggrin has the ability to aggregate keratin filaments by catalyzing the formation of disulfide bridges between the keratin filaments. It is part of the composition of the horny envelope. It plays a role in hydration since it represents the essential reservoir of natural hydration factors (NMF). In fact, filaggrin, after its degradation, is the source of amino acids which will be metabolized to form components of NMF, in particular glutamine is transformed into PCA (hydrolidone carboxylic acid) and histidine into urocanic acid. Thus, a low level of NMF characterizes significant skin disorders, such as psoriasis (practically zero level of NMF), but also ichthyosis (practically zero level of NMF) and atopic dermatitis (low level of NMF compared to a normal skin). The renewal time of the epidermis of a subject affected by psoriasis is reduced (from 8 days instead of approximately 21 to 28 days for a normal epidermis). A phenomenon tending to avoid this decrease in the rate of natural hydration factors or NMF (for “natural moisturizing factors”) is then observed, this phenomenon consisting in an acceleration of the hydrolysis of filaggrin which then tends to be exhausted.

In addition, psoriasis is characterized by very specific alterations of certain epidermal markers, in particular it is observed an increase in the production by keratinocytes of membrane transglutaminase (or transglutaminase 1) which plays a role in the formation of the envelope. cornea. Thus, playing on this rate would also improve the condition of the skin of subjects suffering from this disorder.

Rheumatoid arthritis is also an autoimmune disease with genetic and environmental factors. This pathology is manifested by joint inflammation which is a source of pain and is often accompanied by deformation of the joints. Thus, in many cases of polyarthritis, there is autoimmune involvement of filaggrin. Antibodies commonly known as “antikeratins” are very specifically associated with this pathology. They are linked to the most severe forms of the disease and often precede the appearance of clinical signs. They are synthesized by plasma cells from the synovial membrane. These antibodies have been shown to recognize different molecular forms of profilaggrin and filaggrin. Today, the specific autoantibodies directed against epidermal filaggrin (AFA for Anti-Filaggrin Antibodies) are considered to be the most important and reliable markers of rheumatoid arthritis.

In this context, the Applicant has now come to highlight interesting biological properties of lipids extracted from mother-of-pearl molluscs, namely their action on filaggrin and / or transglutaminase. In particular, it has been demonstrated that these lipids extracted from nacre applied to the skin induce an overexpression of filaggrin and an inhibition of the expression of membrane transglutaminase.

The present invention therefore relates to a pharmaceutical composition comprising lipids extracted from nacre of mother-of-pearl molluscs in a pharmaceutically acceptable carrier.

It also relates to lipids extracted from mother-of-pearl shell molluscs as a medicament, in particular for treating pathologies presenting a decrease in the activity of filaggrin and / or an increase in the activity of membrane transglutaminase, more specifically for treating pathologies linked to a decrease in the skin activity of filaggrin and / or to a cutaneous overexpression of membrane transglutaminase. In particular, the lipids extracted from mother of pearl shell molluscs can be used to treat skin pathologies, more particularly chosen from psoriasis, ichthyosis and atopic dermatitis, but also autoimmune diseases linked to an autoimmune disease of filaggrin, such as in particular rheumatoid arthritis.

Quite surprisingly, it has been observed that the nacre of mother-of-pearl molluscs (molluscs capable of forming nacre), in particular oysters and more specifically oysters of the genus Pinctada and more particularly of the genus Pinctada species margaritifera, lipids promoting skin regeneration. In addition, no intolerance was detected when applying these lipids to human skin. In addition, as specified above, these lipids extracted from mother-of-pearl applied to the skin induce an overexpression of filaggrin and an inhibition of the expression of membrane transglutaminase.

The mother-of-pearl lipids according to the invention are more particularly obtained by their extraction from mother-of-pearl molluscs defined above. The extraction process more specifically comprises the following steps: 1) separating the mother-of-pearl from the rest of the shell of a pearly shellfish, more particularly so as to obtain only the aragonitic layer, 2) grinding the mother-of-pearl to obtain a powder, 3) carrying out a lipid extraction from this powder by subjecting it to minus an extraction solvent or a mixture of solvents, then advantageously 4) extract the lipids from the solvent or mixture of solvents used. Advantageously, the powder obtained in 2) has an average particle size (in number) of less than 20 μm, preferably of the order of 8 μm. The particle size is measured with conventional means within the reach of those skilled in the art, such as the sieving technique and / or the laser reading technique.

The separation of the mother-of-pearl from the rest of the shell can be carried out by any means known per se and in particular by grinding. The grinding of the mother-of-pearl can in particular be carried out in several stages, in particular initially by crushing, then possibly by different grinding techniques.

The mother-of-pearl can advantageously be decontaminated, in particular by washing (s) decontaminant (s), for example in a solution of sodium hypochlorite, then by drying.

The mother-of-pearl can also be sterilized, advantageously after being ground, by any method known per se. In particular, sterilization is carried out by irradiation (gamma-ray irradiation) or hot (dry or humid heat) (Atlan G., Delattre O., Berland S., Le Faou A., Nabias G., Cot D ., Lopez E., Interface between bone and Nacre implants in sheep, Biomaterials, 1999, 20: 1017-1022; Balmain J., Hannoyer B., Lopez E., Fourier transform infrared spectroscopy (FITR) and X-Ray diffraction analyzes of ore and organic matrix during heating of mother of pearl (Nacre) from the shell of the mollusc Pinctada maxima, J. Biomed. Mater. Res. Applied Mat., 1999, 48 (5): 749-754).

Lipid extraction can be carried out by any known method. So for example the powder is brought into contact with a lipid extraction solvent such as a mixture of chloroform and methanol, or ethanol or also hexane, the mixture is optionally stirred for 1 to 6 hours, then separation is carried out, for example by centrifugation or filtration, to separate the solid phase from the liquid phase, advantageously followed by removal of the solvent from the liquid phase, in particular by evaporation, to finally recover the desired lipids. Almost all of the desired lipids are thus recovered. According to a particular mode, the lipids used according to the invention, in particular thus extracted, are not subjected to any chemical modification, in particular a saponification, during, before or after their extraction.

When the lipid extraction solvent is the chloroform / methanol mixture or hexane, the contacting, and optionally stirring, is advantageously carried out at room temperature (between about 18 ° C and 25 ° C). When the lipid extraction solvent is ethanol (absolute ethanol), the contacting, and optionally stirring, is advantageously carried out at a temperature between 30 and 40 ° C, and preferably in weight ratios powder / solvent which correspond to 1/5. The weight ratios of the chloroform / methanol mixture are advantageously 2/1 and the powder / solvent weight ratio is preferably 1/3. When the lipid extraction solvent is hexane, the powder / solvent weight ratio is preferably 1/3.

When the lipids are separated from the solvent used, they are generally in the form of a brown paste which can be directly used in the pharmaceutical composition according to the invention. Other separations can be carried out subsequently from the lipids thus obtained.

Thus, all or part of the lipids of the mother-of-pearl, in particular obtained according to the process described above, can be used according to the present invention. The lipids thus obtained correspond in particular to a mixture of polar and non-polar compounds. This mixture generally comprises ceramides, cholesterol, optionally cholesterol sulfate and / or acetate, fatty acids, triglycerides and non-polar lipids (more non-polar than the previous lipids mentioned), this is more particularly the case for an oyster, advantageously an oyster of the genus Pinctada (generally taken in its natural biotope). Of course, the nature and the quantity of these elements can vary to a large extent, in particular depending on the mollusk, its biotope, the season of the sample and the conditions of the sample.

Thus, to give an order of magnitude, a determination of the lipids extracted

(extraction with mixture of chloroform / methanol solvents - 2/1) of mother-of-pearl

Pinctada margaritifera was carried out on a thin layer after migration with the hexane / diethyl ether / acetic acid solvent on silica gel and coloring with copper sulphate. The percentages expressed as a function of the intensity of coloring of the lipid compounds are as follows:

Cholesterol sulfate: 0.5%

Hydroxylated Ceramides: 2.07%

Nonhydroxylated Ceramides: 1.03% Cholesterol: 5.97%

Fatty acids: 6.24%

Triglycerides: 4.46%

Cholesterol acetate: 0.7%

Apolar lipids (more apolar than the lipids mentioned above): 79.03% The presence of omega among these lipids has been detected.

As the experimental part below shows in more detail, the lipids thus obtained have very interesting properties. These properties include those relating to the effects on filaggrin and membrane transglutaminase mentioned above. Lipids extracted from mother of pearl shell molluscs, when applied to the skin, also restore keratinocyte differentiation with reduction of cellular hyperproliferation. They also have the advantage of total safety and that of having an anti-inflammatory effect.

Thus, the subject of the present invention is a pharmaceutical composition, characterized in that it comprises the lipids as defined above and a pharmaceutically acceptable excipient.

The administration of the composition according to the invention can be carried out topically, and optionally enterally or parenterally. Preferably, the pharmaceutical composition is packaged in a form suitable for topical application.

By enteral route, the pharmaceutical composition can be in the form of tablets, capsules, dragees, syrups, suspensions, solutions, powders, granules, emulsions, microspheres or nanospheres or lipid or polymeric vesicles allowing controlled release. By parenteral route, the composition can be in the form of solutions or suspensions for infusion or for injection.

According to a particular embodiment of the invention, the pharmaceutical composition is intended for local use on the skin. Thus, the pharmaceutically acceptable carrier is in particular an excipient suitable for topical application. Topically, the pharmaceutical composition according to the invention is more particularly intended for the treatment of the pathologies mentioned above, in particular for the treatment of the skin and mucous membranes. It can be in the form of ointments, creams, milks, ointments, powders, soaked pads, solutions, gels, sprays, lotions or suspensions. It can also be in the form of microspheres or nanospheres or vesicles lipid or polymeric or polymeric patches and hydrogels allowing controlled release. This topical composition can be in anhydrous form, in aqueous form or in the form of an emulsion (water / oil, oil / water emulsion or multiple emulsion).

The lipids according to the invention are used, preferably topically, at a concentration generally between 0.02% and 3% by weight, preferably between 0.25 and 2% by weight, and advantageously between 0.5 and 1%, relative to the total weight of the composition.

In particular, the therapeutic composition according to the invention is characterized in that it contains, in combination with inert excipients, a therapeutically effective amount of lipids extracted from mother-of-pearl shell molluscs as defined above, in particular in the treatment of pathologies presenting a decrease in the activity of filaggrin and / or an increase in the activity of membrane transglutaminase, more specifically for treating pathologies linked to a decrease in the cutaneous activity of filaggrin and / or to a cutaneous overexpression of transglutaminase membrane.

The invention also resides in a method of treating pathologies or traumas linked to a decrease in the activity of filaggrin and / or an increase in the activity of membrane transglutaminase in subjects suffering from such pathologies or traumas, comprising the administration to these mammals with a therapeutically effective amount of lipids extracted from nacre as defined above, in particular for treating pathologies linked to a reduction in the cutaneous activity of filaggrin and / or to a cutaneous overexpression of the membrane transglutaminase.

More specifically, pathologies linked to the decrease in the skin activity of filaggrin and / or to a cutaneous overexpression of membrane transglutaminase are skin pathologies, more particularly chosen from psoriasis, ichthyosis and atopic dermatitis, and autoimmune diseases linked to an autoimmune involvement of filaggrin, such as in particular rheumatoid arthritis.

In the context of the invention, the term “treatment” designates preventive, curative, palliative treatment, as well as the management of patients (reduction of suffering, improvement of the quality of life, slowing down of the progression of the disease ), etc.

The treatment can also be carried out in combination with other ingredients or treatments, such as in particular other active compounds for treating the pathologies or traumas specified in the present application.

Other treatments may be those mentioned above, including a variety of topical, phototherapeutic and oral treatments. Topical treatments include steroids, tar, anthralin, vitamin D3 and the like, retinoids, and UV radiation. Phototherapy includes treatment followed medically with type B ultraviolet radiation (UV-B) or treatment with psoralen in combination with UV-A. Oral treatments include administration of methotrexate, oral retinoids or cyclosporine.

The pharmaceutical compositions or medicaments according to the invention may also comprise at least one other therapeutically active ingredient, chosen in particular from those mentioned above, for simultaneous, separate or spread over time use, in particular during treatment in a subject suffering from a pathology or trauma related to a decrease in the activity of filaggrin and / or an increase in the activity of membrane transglutaminase, as defined above. The pharmaceutical compositions or medicaments according to the invention advantageously comprise one or more inert excipients or vehicles, that is to say pharmaceutically inactive and non-toxic. Mention may be made, for example, of saline, physiological, isotonic, buffered solutions, etc., compatible with pharmaceutical use and known to those skilled in the art. The compositions may contain one or more agents or vehicles chosen from dispersants, solubilizers, stabilizers, preservatives, etc. Agents or vehicles usable in formulations (liquids and / or injectable and / or solids) are in particular methylcellulose, hydroxymethylcellulose, carboxymethylcellulose, cylclodextrins, polysorbate 80, mannitol, gelatin, lactose, vegetable oils or animal, acacia, etc. The compositions may be formulated in the form of an injectable suspension, gels, oils, tablets, suppositories, powders, capsules, capsules, etc., optionally by means of dosage forms or devices ensuring sustained and / or delayed release. For this type of formulation, an agent such as cellulose, carbonates or starches is advantageously used.

The compositions as described above can of course also contain pharmacodynamically active additives or a combination of these additives, and in particular: wetting agents; emollients; moisturizers, such as glycerol, PEG 400, or even urea; other anti-psoriatic agents such as in particular steroids, tar, anthralin, vitamin D3 and the like, and retinoids.

These compositions may also contain flavor enhancers, preservatives such as parahydroxybenzoic acid esters, stabilizers, moisture regulators, pH regulators, osmotic pressure modifiers , emulsifiers, UV-A and UV-B filters, antioxidants, such as a- tocopherol, butylhydroxyanisole or butylhydroxytoluene.

Of course, those skilled in the art will take care to choose the optional compound (s) to be added to these compositions in such a way that the advantageous properties intrinsically attached to the present invention are not or substantially not altered by the addition envisaged.

Administration can be carried out by any method known to a person skilled in the art, in particular by oral, topical or injection route, typically by intraperitoneal, intra-cerebral, intra-thecal, intravenous, intra-arterial or intramuscular. Topical or oral administration is preferred. For long-term, non-topical treatment, the preferred route of administration will be sublingual, oral or transcutaneous.

For injections, the compounds are generally packaged in the form of liquid suspensions, which can be injected using syringes or infusions, for example. It is understood that the flow rate and / or the dose injected, or in general the dose to be administered, can be adapted by a person skilled in the art depending on the patient, the pathology, the mode of administration, etc. it is understood that repeated administrations can be carried out, optionally in combination with other active ingredients or any pharmaceutically acceptable vehicle (buffers, saline, isotonic solutions, in the presence of stabilizing agents, etc.).

According to a particular aspect, the invention relates to a device, in particular suitable for subcutaneous or percutaneous injection, comprising the lipids as defined above and a physiologically acceptable excipient, which is in particular suitable for subcutaneous injection or percutaneous. This device can in particular be in the form of syringes or infusions. The invention can be used in mammals, in particular in humans.

Other aspects and advantages of the present invention will appear on reading the examples which follow, which should be considered as illustrative and not limiting.

EXAMPLES

This part demonstrates the effectiveness of lipids as defined above.

1- Preparation of lipids extracted from mother-of-pearl

Extraction of the residue with a Chloroform / methanol mixture: 60 g of the powder obtained from oyster nacre Pinctada margaritifera is mixed with 120 ml of the chloroform / methanol mixture (weight ratio: 2/1). The mixture is stirred at ambient temperature for approximately 4 hours. It is filtered, then evaporated to recover the lipid part.

The lipids obtained are incorporated into a cream base called an excipient below to give Formulations P1 and P2 indicated below.

2-Preparation of explants and delipidation:

On a skin plasty, an ether / acetone mixture was applied to a defined area. In this delipidated area, 15 explants were removed. 6 other explants were taken from a non-delipidated area.

Distribution of the 15 delipidated explants into 5 lots:

- D (Control Delipidated Skin, 6 explants) - DE (Delipidated Skin + Excipient, 3 explants)

- DP1 (Delipidated Skin + Product 1, 3 explants)

- DP2 (Delipidated Skin + Product 2, 3 explants) Distribution of the 6 non-delipidated explants into two batches No (Normal Skin at To) and N3 (Normal Skin at T 3 hours).

3-Products tested:

The products tested are:

- Basic formulation: Excipient,

- Formulation P1 at 0.5% by weight of lipids - Formulation P2 at 1.0% by weight of lipids

4-Application of the products: The products to be tested were applied to the explants as soon as they were produced. They were applied topically (4 mg / explant) for 3 hours on lots DE, DP1 and DP2; batches No, N3 and D receive no treatment.

5-Histology: At time T0, at the end of the delipidation, 3 explants of lots No and Do are removed and fixed for half in ordinary Bouin, and for other half frozen. At time 3 hours after the start of treatment, the 3 explants of each batch (N3, D3, DE, DP1 and DP2) are removed and fixed in the same way.

The histological study consists of:

- Histological analysis of the stratum corneum by staining with Masson trichrome.

- The labeling of filaggrin by the monoclonal anti-filaggrin body (ref BT 576 from BTI Cliniscience) Clone OKTB1 revealed in immunofluorescence with a biotin / streptavidin enhancer system and nuclei counter-stained with propidium iodide.

- The labeling of membrane transglutaminase by the anti-TGM monoclonal antibody (Harbor Products TEBU ref 5003) clone B.C1 revealed in immunofluorescence with a biotin / streptadivine amplifier system and nuclei counter-stained with propidium iodide.

6-RESULTS:

Morphological observation of the stratum corneum after staining with Masson trichrome:

Skin not delipidated at TO (No): The stratum corneum is quite compact, not very flaky, keratinized at the surface and at the base.

Delipidated skin at To (Do):

The stratum corneum is more compact and more keratinized on the surface and at its base.

Normal skin at 3H (N3):

The stratum corneum is more or less compact, not very keratinized on the surface and basal.

Delipidated skin at 3 a.m. (D3):

The stratum corneum is compact, markedly keratinized on the surface and basal.

Delipidated skin + excipient (DE):

The stratum corneum is quite flaky and slightly keratinized.

Delipidated skin + formulation containing 0.5% of lipids (DP1):

The stratum corneum is slightly laminated, slightly keratinized on the surface and clearly basal.

Delipidated skin + 1.0% lipid formulation (DP2): The stratum corneum is more or less laminated, slightly keratinized at the surface and more clearly at basal. Close to P1.

Filaggrin immunolab:

Non-defatted skin at To (No):

The marking is strong and very irregular. It is observed on 6 to 7 cell bases and clearly overexpressed compared to normal.

Delipidated skin at To (Do):

The marking is close to that observed on non-delipidated skin at To, but present on a smaller number of cell bases with slight marking in the epidermal structures, marking which is sometimes observed on very dry skin.

Normal skin at T 3h (N3):

The marking is strong and very irregular. It is observed on 3 to 7 cell bases and clearly overexpressed compared to normal.

The marking is identical to that observed on the non-delipidated skin at T0.

Delipidated skin at T3h (D3):

The marking present is variable, generally observed on a smaller number of cell bases, and much less strong and very irregular.

Delipidated skin + Excipient (DE):

The marking is present on 4 to 5 cell bases. It is irregular and slightly higher than that observed on defatted skin at T3h.

Delipidated skin + formulation at 0.5% lipid (DP1) at 3 o'clock: The marking is strong and more or less regular. It is observed on 6 to 7 seats cellular and markedly over-expressed compared to normal.

The marking is close to that observed on the non-delipidated skin at T3h.

Delipidated skin + 1.0% lipid formulation (DP2): The labeling is close to that observed with P1 and present on an identical number of cell bases.

Labeling of membrane transglutaminase:

Non delipidated skin at T0 (N0):

The marking is very fine, fairly weak and irregular on 2 to 3 cell bases.

Delipidated skin at To (Do):

The marking is very fine, more or less weak and irregular on 2 to 3 cell bases. It is close to that of normal skin at To.

Normal skin at T 3h (N3):

The marking is fine, fairly clear and fairly regular on 2 to 3 cell bases. It is close to that of normal skin at To.

Delipidated skin at T 3h (D3):

The marking is very weak on 1 cell base and often absent from the stratum corneum.

Delipidated skin + Excipient (DE):

The marking is fairly clear and more or less regular on 2 to 3 cell bases.

Delipidated skin + formulation containing 0.5% of lipids (DP1):

The marking is weak, more or less regular and observed on 2 to 3 cell bases. Delipidated skin + 1.0% lipid formulation (DP2):

Marking is practically absent from the stratum corneum.

GENERAL MORPHOLOGY OF THE STATUM CORNEUM

At TO, on the non-defatted skin, the stratum corneum is quite compact and keratinized on the surface and at the base. It is more compact and keratinized on defatted skin. This aspect shows a structure of dry skin.

At T 3h, on normal skin, it shows a relatively flaky structure. It remains fairly compact on defatted skin. On defatted skin treated with the P1 formulation, it is slightly less compact and more or less laminated. On the one treated with the P2 formulation, aspects close to those observed with the P1 formulation are observed.

EXPRESSION OF FILAGGRIN:

At T0, on normal and delipidated skin, filaggrin is strongly overexpressed, present on 6 to 7 cell layers on the entire stratum corneum.

At T3h, on defatted skin, the filaggrin is less strong, very irregular and present on a very variable number of cellular bases. On normal skin, it is identical to that of T0 skin.

With the excipient, the expression of filaggrin is slightly higher than that observed on defatted skin without product at 3 h. The P1 formulation, with 0.5% mother-of-pearl lipids, induces an over-expression of filaggrin, which is present on 6 to 7 cell layers and is of an intensity greater than that observed on normal skin at T3h.

The P2 formulation, with 1% mother-of-pearl lipids, induces a very clear over-expression of filaggrin. It is very slightly higher than that observed with the formula P1.

EXPRESSION OF MEMBRANE TRANSGLUTAMINASE:

At T0, on normal and defatted skin, the membrane transglutaminase is very weak, very irregular and present on 2 to 3 cellular foundations.

At T 3h, on defatted skin, the membrane transglutaminase (TGM) is very weak and present on one or two cell bases. On normal skin, it is slightly higher than that of skin at T0. With the excipient, the expression of TGM appears more marked than normal skin and defatted without treatment.

The P1 formulation, with 0.5% mother-of-pearl lipids, induces a very low expression of TGM much lower than that observed on the defatted skin at T3h and treated with the excipient.

The P2 formulation, with 1% mother-of-pearl lipids, practically does not induce TGM expression.

CONCLUSION

The proteolysis of filaggrin produces, among other things, many amino acids which are part of the composition of NMF (Natural Hydration Factor). These NMF are located between the corneocytes of the stratum corneum. The hyper-expression of filaggrin shows the dry skin character of the plasty used. This character was amplified by defatting. The formulations P1 and P2 induce, on defatted skin, an expression of filaggrin close to that of normal skin. They brought to the stratum corneum the elements necessary for the rapid reconstitution of the intercellular cement.

The two formulations P1 and P2 are active in the reconstitution of intercellular cement, with a slight advantage to the formulation P2 with 1% mother-of-pearl lipids.

The composition of the horny envelopes is regulated by membrane transglutaminase. The low expression of TGM, observed at TO is a sign of a dry skin character. It is amplified by the delipidation of the plasty with the mixture of solvents, thus increasing the alteration of these envelopes. The skin has therefore drawn from its elements recomposing the structure of the horny envelopes: the TGM.

The two formulations, P1 and P2 seem to inhibit the expression of TGM with a dose effect. These products appear to prevent a return to normal levels of

TGM.

The two formulations P1 and P2 inhibit the expression of membrane transglutaminase.

Claims

1. Pharmaceutical composition comprising lipids extracted from mother of pearl shell molluscs in a pharmaceutically acceptable carrier.

2. Pharmaceutical composition according to claim 1, characterized in that the pearl molluscs are oysters.

3. Pharmaceutical composition according to claim 2, characterized in that the oysters are oysters of the genus Pinctada and more particularly of the genus Pinctada species margaritifera.

4. Pharmaceutical composition according to one of the preceding claims, characterized in that the pharmaceutically acceptable carrier is an excipient suitable for topical, enteral or parenteral application.

5. Composition according to the preceding claim, characterized in that the pharmaceutically acceptable carrier is an excipient suitable for topical application.

6. Composition according to the preceding claim, characterized in that the lipids are present at a concentration of between 0.02% and 3% by weight, preferably between 0.25 and 2% by weight, and advantageously between 0.5 and 1%, relative to the total weight of the composition.

7. Composition according to any one of the preceding claims, characterized in that it is intended to treat pathologies having a decreased filaggrin activity and / or increased membrane transglutaminase activity.

8. Composition according to the preceding claim, characterized in that it is intended to treat pathologies linked to a decrease in the cutaneous activity of filaggrin and / or to a cutaneous overexpression of the membrane transglutaminase.

9. Composition according to any one of the preceding claims, characterized in that it is intended to treat skin pathologies, more particularly chosen from psoriasis, ichthyosis and atopic dermatitis.

10. Composition according to any one of the preceding claims 1 to 8, characterized in that it is intended for treating autoimmune diseases linked to an autoimmune disease of filaggrin, in particular rheumatoid arthritis.

11. Composition according to any one of the preceding claims 1 to 10, characterized in that it also comprises at least one other therapeutically active ingredient for simultaneous, separate or spread over time use.

12. Composition according to the preceding claim, characterized in that the other therapeutically active ingredient is chosen from steroids, tar, anthralin, vitamin D3 and the like, and retinoids.

13. Lipids extracted from mother-of-pearl shell molluscs as defined according to one of claims 1 to 3, as a medicament.

14. Device comprising lipids as defined in one of claims 1 to 3 and a physiologically acceptable excipient.

15. Device according to the preceding claim, characterized in that its shape is suitable for subcutaneous or percutaneous injection, in particular in the form of a syringe or an infusion.