LIFESTYLE COSMETICS UNTREATED CONTROL PLACEBO REFORCYL -AION 1%
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Figure 1: Autophagy in normal human epidermal keratinocytes (NHEK): Left: Untreated control staining for nucleus (blue), Golgi apparatus (green) and active mitochondria (magenta). Middle: Starvation induces autophagy indicated by decomposition of Golgi apparatus. Right: Pumpkin seed extract induces autophagy and strengthens the mitochondrial network
This cellular waste, such as dysfunctional mitochondria, massively impedes the survival or differentiation of cells. Such material has to be removed and reused.5
It is for this purpose that
the process of autophagy has evolved. Autophagy means ‘self-digestion’. Essentially,
cell membranes provided by the Golgi apparatus are used to enclose material to be recycled. The fusion with lysosomes allows the complete degradation of the captured valuable material to form amino acids, sugars, nucleotides and fatty acids, the basic building blocks for all new macromolecules to be formed in cells. This allows the remaining intact mitochondria to be fed again for the production of energy (ATP) and stalled cell processes can be restarted. Autophagy is important, for example,
to maintain the constant division of cells. It is also particularly relevant to the terminal differentiation process in the epidermis - the transformation of keratinocytes into corneocytes. Thus, the maximum rate of autophagy occurs in the stratum granulosum because here the entire cell material has to be transformed into NMF, barrier lipids and keratin. Since these processes consume enormous amounts of energy, mitochondrial activity is also at its maximum here, as already explained. Epidermal fitness thus depends to a
large extent on the status of autophagy and mitochondrial energy production. Both need to be at the maximum to ensure the terminal differentiation of keratinocytes into corneocytes. External factors such as ROS and UV radiation, but also intrinsic factors such as ageing, stress, inappropriate diet and unhealthy lifestyle contribute to the fact that these processes no longer function as they should.6 If autophagy is disturbed, a fully intact skin barrier cannot be created.7
The skin
can dry out and then assumes a stressed appearance. The ideal solution
would be to restart autophagy and provide nutrients for energy production so that good terminal differentiation
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becomes once again possible. However, a supply of nutrients inhibits autophagy. With Reforcyl®-Aion (INCI: Propanediol, Water, Cucurbita Pepo (Pumpkin) Seed Extract, Citric Acid), hereafter known as the pumpkin seed extract, we have found a way to optimally supply the cells with nutrients and still activate autophagy. The outcome is that the maximum amount of energy and building blocks can be provided to create an optimal skin barrier for a healthy, youthful-looking skin.
Material and Methods Extract
The pumpkin seed extract is the water-based extract of the press cake remaining after pumpkin oil production. We use organically grown Styrian pumpkins from Austria to meet highest quality standards. The extract is rich in amino acids and carbohydrates and contains autophagy inducing factors. The pumpkin seed extract is a carbon neutral Rahn cosmetic active.8
In vitro Normal human epidermal keratinocytes (NHEK) were cultivated on a coverslip for 24 hours in low nutrition conditions (starvation). After the incubation period, the medium was replaced by fresh medium with and without pumpkin seed extract, for 24 hours. After the incubation period, samples were stained with MitoTracker Deep Red FM for 45 minutes and anti-Giantin antibody, a Golgi marker overnight. Four technical replicates were analysed for each experimental condition.
In vivo
The study was performed in accordance with the principles of good laboratory practice (GLP), good clinical practice (GCP) and in compliance with the quality assurance system requirements. The study was also conducted in accordance with the World Medical Association ethical principles defined in the Declaration of Helsinki. All study participants provided their written informed consent at the beginning of the study. Fifty-five Caucasian subjects aged 50 – 65 years applied an emulsion containing 0% or 3% pumpkin seed extract twice daily for 56 days on the face.
Results and discussion During autophagy, double membrane vesicles called autophagosomes are formed. This process requires a considerable amount of membrane. The Golgi vesicles are temporarily while mitochondria are irreversibly used as membrane sources for autophagosome formation. A stress situation such as starvation is similar to the physiological condition in ageing skin. The unfavourable constellation in ageing skin, namely decreased vascularisation, insufficient nutrition supply and in addition impairment of autophagy and mitochondrial activity lead to cellular waste accumulation and, as a consequence, to a decreased ability for the terminal differentiation process from a keratinocyte into a corneocyte. This will lead to an impaired skin barrier formation and skin ageing. Impaired autophagy in fibroblasts and sebocytes will impair the structure of the dermis or sebum production, respectively. Autophagy, under low nutrition supply (ageing, starvation), will lead to a degradation of dysfunctional mitochondria, as it is supposed to do. However, the newly generated building blocks are not sufficient to increase the number of mitochondria as required for the energy consuming terminal differentiation process. As the pumpkin seed extract is
April 2023 PERSONAL CARE
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