Evidence for the existence of a body-brain connection for skin moisturization / Johann W. Wiechers in IFSCC MAGAZINE, Vol. 10, N° 3 (07-08-09/2007)

[article]  inIFSCC MAGAZINE > Vol. 10, N° 3 (07-08-09/2007) . - p. 209-213 Titre : Evidence for the existence of a body-brain connection for skin moisturization Type de document : document électronique Auteurs : Johann W. Wiechers, Auteur ; Anthony Vincent Rawlings, Auteur ; Wei G. Hansen, Auteur Année de publication : 2007 Article en page(s) : p. 209-213 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Estrogènes Les Å“strogènes constituent un groupe de stéroïdes, dont la fonction, à l'état naturel, est d'être une hormone sexuelle femelle primaire. Ils sont produits en premier lieu par le développement des follicules des ovaires, le corps jaune (corpus luteum) et le placenta. Certains Å“strogènes sont également produits en petites quantités par d'autres tissus tels le foie, la surrénale, les seins et le tissu adipeux. Ces sources secondaires d'Å“strogènes sont particulièrement importantes chez les femmes lors de la post-ménopause. Les trois Å“strogènes naturels sont l'estradiol, l'estriol et l'estrone. Dans le corps, ils sont tous produits au départ d'androgènes sous l'effet d'enzymes. L'estradiol est produit à partir de la testostérone et l'estrone à partir de l'androstènedione. L'estrone est beaucoup moins puissante que l'estradiol, et chez les femmes en post-ménopause, on trouve plus d'estrone que d'estradiol. Bien que les Å“strogènes soient présents dans les deux sexes, on en trouve une quantité significativement plus importante chez les femmes que chez les hommes. Elles favorisent le développement des caractères sexuels secondaires, comme les seins, et sont également impliquées dans le contrôle du cycle menstruel, ce qui explique pourquoi la plupart des contraceptifs hormonaux comme les pilules contraceptives en contiennent. L'usage d'Å“strogènes, en particulier s'ils ne sont pas associés à la progestérone, est un traitement (traitement hormonal substitutif) controversé des symptômes de la ménopause. En plus de leur rôle dans la reproduction, féminine mais aussi masculine, les Å“strogènes sont impliqués dans le développement du système nerveux central, dans l'homéostasie du squelette et du système cardio-vasculaire. Ils ont également des effets sur le foie et le tissu adipeux. Grossesse Peau -- Physiologie Peau -- Soins et hygiène Produits hydratants Spectrométrie infrarouge Tabac -- Effets physiologiques Testostérone Vieillissement cutané Tags : Relation  corps-cerveau  Hydratation  peau Index. décimale : 668.5 Parfums et cosmétiques Résumé : Maintenance of the right water levels in the skin is of crucial importance to maintain healthy, young-looking skin. Moisturizing products have therefore aimed to influence the constitutive levels of natural moisturizer factor (NMF) and/or the formation of the skin lipid barrier. In humans, keratinocyte differentiation is influenced by sex hormones, in particular positively by estrogen and negatively by testosterone. It has been noted that postmenopausal women experience a decline in estrogen levels and a concomitant drop in skin moisturization. In our previous near-infrared reflectance (NIR) spectroscopy work on human skin, we noted that skin moisturization was influenced by gender, age, psychological stress and lifestyle habits such as alcohol consumption and smoking. Many of these also affect the level of sex hormones. We therefore re-evaluated NIR spectra from which we had already assessed the levels of skin moisturization in human volunteers to determine their levels of estrogen and testosterone non-invasively. We subsequently built mathematical models to link skin moisture content to the levels of these sex hormones. In this way, we were able to establish the importance of sex hormones in skin moisturization. In men, skin moisturization levels are linked to their estrogen levels, whereas in females, skin moisturization levels are linked to both estrogen and testosterone concentrations. From the medical literature, it is known that smoking is associated with increased testosterone and reduced estrogen levels, which suggests that people that smoke are characterized by less hydrated skin as well as by increased testosterone levels. On the other hand, pregnant females that have significantly elevated estrogen to progesterone ratios, i.e. their increase in estrogen level exceeds their increase in testosterone levels, also often remark that their skin is well hydrated, confirming the link between sex hormone levels and skin moisturization. For them, we found a good correlation coefficient for skin moisturization levels and their estrogen to testosterone ratio. This work does not, however, answer question of a cause-and-effect relationship between the two. Increased levels of estrogen can either directly increase skin moisture levels or do so via a positive effect on skin barrier formation. It does, however, reveal once again the existence of a connection between our body (the skin) and our brain. Synthesis of sex hormones is regulated via the pituitary gland in our brain and it can therefore be argued that skin moisturization is directly or indirectly regulated via our brain. As many other factors like smoking and alcohol consumption actually influence estrogen levels in our blood, the influence of our brain on maintaining a skin moisture homeostasis may actually be much more pronounced than hitherto assumed. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3795 [article]

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Factors influencing skin moisturization signal using near-infrared spectroscopy / Johann W. Wiechers in IFSCC MAGAZINE, Vol. 6, N° 1 (01-02-03/2003)

[article]  inIFSCC MAGAZINE > Vol. 6, N° 1 (01-02-03/2003) . - p. 19-26 Titre : Factors influencing skin moisturization signal using near-infrared spectroscopy Type de document : texte imprimé Auteurs : Johann W. Wiechers, Auteur ; Marchel Snieder, Auteur ; Nico A. G. Dekker, Auteur ; Wei G. Hansen, Auteur Année de publication : 2003 Article en page(s) : p. 19-26 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cosmétiques Hygrométrie Peau -- Anatomie et histologie Peau -- Physiologie Peau -- Soins et hygiène Produits hydratants Spectroscopie infrarouge proche Index. décimale : 668.5 Parfums et cosmétiques Résumé : The effectiveness of skin moisturizers can be measured by electrical and spectroscopic methods. We explored the benefits of near infrared (NIR) spectroscopy for the investigation of skin moisturization. This technique provides information on the interaction of water molecules with its surrounding structures and has been used to identify whether the water is freely moving, loosely or tightly bound. We first assessed the penetration depth of NIR radiation and found it to go as deep as the dermis. Using second-derivative spectra, the presence of the various water peaks, representing the different forms of water were identified and we derived a "total water" parameter from this. We used this parameter to study the influence of anatomical site, gender and age volunteer, emotional status of the subject and effect of smoking and relative humidity on the occurrence, abundance and type of water. The anatomical site certainly contributed to the overall variability in signal, as did gender, age and smoking. Care had to be taken near blood vessels as blood components could interfere with the signal, as well as the location of the measuring spot. Whereas the gender of volunteers could be easily detected in a spectrum, possibly based on the sex hormones in their blood, we also noted that females had more water in their skin than males. As with superficial water, the deeper water content decreased with age. Smoking also negatively influenced the water content of the skin: smoking aged the skin by about 15 years in terms of its water content. We conclude that NIR is an interesting new technology that may yield more fundamental insight into the process of skin moisturization, especially when combined with other techniques. However, volunteers need to be very carefully selected, as without this, differences between subjects will obscure the effects of moisturizing ingredients. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10612 [article]

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