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Accentuate and Enhance Youth in Mature Skin



Lipotec has developed three peptides that rejuvenate and enhance skin due to their ability to ameliorate skin firmness, suppleness and tightness.



By Marta Rull, Cristina Davi, Elena Cau00f1adas, Nu00faria Almiu00f1ana and Raquel Delgado, Lipotec S.A. Pol. Ind. Camu00ed Ral. Isaac Peral, 17. 08850 Gavu00e0, Spain.



Published August 23, 2012
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Accentuate and Enhance Youth in Mature Skin

The differences between young and old people are generally quite clear, becoming even more obvious when comparing skin conditions. This extensive organ suffers important physiological changes when individuals get older due to internal and external factors, which lead to its visible deterioration with a loss of firmness, elasticity and flaccidity. Thus, rejuvenating the skin by increasing these essential lost properties would help to regain skin youthful conditions and look.


Skin quality progressively worsens when aging, greatly differing from the properties and characteristics that it previously had. Several factors contribute to these negative changes but photoaging, environmental factors, chronological aging and hormonal deficiency are known to be the most decisive, becoming the main cause by which skin turns less elastic and firm, thicker and more atrophic.1


Elasticity is a mechanical property basically influenced by elastin, a skin protein that constitutes the connective tissue together with collagen and glycosaminoglycans. They are responsible for skin firmness and resistance to stretching. Elastin and collagen fibers are altered by both photoaging and chronologic aging, causing the atrophy of the extracellular matrix (ECM), loss of 3D skin integrity and undesirable visible signs (sagginess and wrinkles).2 Even though there are many environmental factors that negatively affect skin properties, sun exposure is the major reason for extrinsic aging, inducing a proteolytic activation and abnormal ECM turnover increase.


The ECM is affected by the slower synthesis and turnover of new components, as well as greater enzyme proteolytic degradation of collagen and elastin fibers that occur from the 40s onwards. As key compounds of this matrix, collagen and elastin must remain intact but, they are degraded by Matrix Metalloproteinases (MMP) and other enzymes such as collagenases, neutrophil elastases and skin fibroblast elastases that also deteriorate other connective tissue proteins.3


The degradation of the main ECM compounds flattens the Dermo-Epidermal Junction line (DEJ) and lowers skin resistance. This happens firstly because the DEJ, formed by basal and reticular lamina, is in direct contact with the ECM and secondly, because of the rich content in type IV collagen, proteoglycans and laminin glycoproteins that the basal lamina of the DEJ has, which provide structural support and bioadhesive properties.


Collagen also interacts with the proteoglycan decorin, which in turn influences collagen fibrillogenesis by regulating excessive bundle-like aggregation of collagen. Due to the progressive reduction of this functional proteoglycan when aging, collagen fibers are disrupted and skin tensile strength is reduced.


Following collagen, the second most abundant protein in the ECM is laminin, which is involved in cell proliferation, migration and adhesion. Several features of the DEJ become altered with time such as the reduction in the anchoring ability of keratinocytes and in the synthesis of laminin-5. These changes induce a loss of contact between dermis and epidermis that lead to skin elasticity loss and sagginess.


Lipotec developed three specific peptides to enhance rejuventation and reduce the aging effects. Relistase is a tetrapeptide (Acetylarginyltryptophyl diphenylglycine) that stimulates skin elasticity and tightness, Serilesine (Hexapeptide-10) maintains many of the characteristics of the laminin-1 native protein (sequence from its alpha chain) and promotes cell adhesion and proliferation, while Decorinyl (liposomal system with Tripeptide-10 citrulline) is a mimic tetrapeptide of the binding sequences of decorin, which targets collagen fiber organization, ensures uniformity of fibril diameter and increases cutaneous suppleness thanks to a better cohesion of collagen fibers.


Several in vitro and in vivo tests confirmed the excellent properties of this complete anti-aging treatment, which improves overall conditions of mature skin.


Modulation of ECM Damaging and Beneficial Compounds


The fluorescence released by the fluorogenic elastase substrate V when digested by human neutrophil elastase was monitored in this in vitro assay. Acetylarginyltryptophyl diphenylglycine greatly minimized the activity of this enzyme in a dose-response manner, decreasing it up to 86% at the highest tested concentration.

Fig. 1. Inhibition of human neutrophil elastase activity.
Additionally, the in vitro stimulation of type I collagen induced by Acetylarginyltryptophyl diphenylglycine on human dermal fibroblasts was evaluated by an ELISA assay, measuring the amount of labelled antibody bound to the matrix using a colorimetric substrate. This tetrapeptide increased type I collagen synthesis induction by 99% on the fibroblasts cell cultures at 21µM.



Enhancement of Skin Elasticity and Tightness


A cream containing 4% of a solution with Acetylarginyltryptophyl diphenylglycine or a placebo cream was applied on the thighs of 20 volunteers twice a day for 8 weeks in order to determine skin elasticity at the beginning and after 4 and 8 weeks. The elasticity of the skin significantly improved by 11.7% and 14.0% thanks to the cream containing the active peptide and the maximal deformation values were reduced by -5.5% and -15.6% after 4 and 8 weeks respectively.

Fig. 2. Overall elasticity of the skin.




Increased Density and Expression of Laminin and Integrin


The expression of laminin-5 and α6-integrin was determined by immunohistochemistry in skin biopsies of 3 volunteers, before and after a two-month treatment with a cream containing 10% of a solution containing Hexapeptide-10. Due to the action of this peptide, laminin-5 and α6-integrin expression increased an average of 305% and 405% after 4 and 8 weeks respectively.


In order to assess the density of the dermis, a panel of 20 volunteers applied a cream containing 10% of a solution with Hexapeptide-10 on one side of the face and a placebo cream on the other, twice a day for 54 days. The high frequency echograph Dermascan C 2D was used for the measurements, which permits to obtain skin bi-dimensional images and study the thickness of the dermis and epidermis. After 54 days, the cream containing the hexapeptide induced a 19% long-term redensifying effect.


Fig. 3. Skin image of a volunteer before (left) and after the treatment (right).



Improvement of Collagen and Skin Suppleness


Before and after a two-month treatment with a cosmetic formulation containing 0.01% Tripeptide-10 Citrulline, the collagen fibril diameter of skin biopsies of three volunteers was evaluated by TEM. The average decrease of the standard deviation of collagen fibril diameters was 9.6% after the treatment with the peptide, which implied a higher uniformity of collagen fibrils.

Fig. 4. TEM micrographs of dermal collagen from skin biopsies of a volunteer before and after the treatment.
0 Months
2 Months
Skin suppleness was evaluated in a group of 22 volunteers that applied a cream containing 5% of the liposomal system with Tripeptide-10 Citrulline on the temple for 28 days, while another group applied a placebo cream. Variations on this parameter were measured at the beginning and after 28 days by a MPA 580 Cutometer and results showed that the active peptide induced a 54% increase in suppleness, ameliorating in 95% of the volunteers.<


Conclusions


The skin suffers inevitable negative changes over the years caused by external but also internal agents, which lead to a deterioration of skin properties. An improvement of suppleness, tightness and firmness would certainly help to revert these undesired modifications and stimulate the skin to regain its younger look and properties.


It was proved that Relistase increased cutaneous elasticity and compactness by reducing elastase activity and boosting collagen synthesis. On the other hand, Serilesine induced a redensifying dermis effect by stimulating laminin-5 and α6-integrin expression. Finally, Decorinyl diminished the variability of the collagen fibril diameters and raised their uniformity, which is translated into a skin flexibility growth and a recovery of the skin morphology and mechanical properties.


These three peptides are an excellent combination to apply in anti-aging cosmetic formulations in which rejuvenate and enhance skin youth is the main goal, due to its demonstrated capacities in ameliorating skin firmness, suppleness and tightness.


References
1. Pons Gimier L, Parra Juez JL. Ciencia Cosmética. Bases fisiológicas y criterios prácticos. Consejo General de Colegios Oficiales de Farmacéuticos. 1995.
2. Saarialho-Kere U, Kerkelä E, Jeskanen L, Hasan T, Pierce R, Starcher B, Raudasoja R, Ranki A, Oikarinen A, Vaalamo M. Accumulation of matrilysin (MMP-7) and macrophage metalloelastase (MMP-12) in actinic damage. J Invest Dermatol. 113(4): 664-672, 1999.
3. Bernstein EF et al. Long-term sun exposure alters the collagen of the papillary dermis. J Am Acad Dermatol. 34: 209-218, 1996.


More Info:
Domenico Palella, chief executive officer, Lipotec LLC, Jersey City, NJ. Tel: 201.633.4662; Fax 201.484.7201; Email: salesoffice@lipotec.com; Website: www.lipotec.com


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