Kirsten Sauermann

Novel Aspects of Intrinsic and Extrinsic Aging of Human Skin: Beneficial Effects of Soy Extract¶

Abstract Biochemical and structural changes of the dermal connective tissue substantially contribute to the phenotype of aging skin. To study connective tissue metabolism with respect to ultraviolet (UV) exposure, we performed an in vitro (human dermal fibroblasts) and an in vivo complementary DNA array study in combination with protein analysis in young and old volunteers. Several genes of the collagen metabolism such as Collagen I, III and VI as well as heat shock protein 47 and matrix metalloproteinase-1 are expressed differentially, indicating UV-mediated effects on collagen expression, processing and degradation. In particular, Collagen I is time and age dependently reduced after a single UV exposure in human skin in vivo. Moreover, older subjects display a lower baseline level and a shorter UV-mediated increase in hyaluronan (HA) levels. To counteract these age-dependent changes, cultured fibroblasts were treated with a specific soy extract. This treatment resulted in increased collagen and HA synthesis. In a placebo-controlled in vivo study, topical application of an isoflavone-containing emulsion significantly enhanced the number of dermal papillae per area after 2 weeks. Because the flattening of the dermal–epidermal junction is the most reproducible structural change in aged skin, this soy extract appears to rejuvenate the structure of mature skin.

Age related changes of human skin investigated with histometric measurements by confocal laser scanning microscopy in vivo

Background/aims: The confocal laser scanning microscope Vivascope (Lucid, Henrietta) allows skin to be studied in real‐time with a resolution of 0.5 µm horizontal and 1.3 µm vertical in vivo. In this study, we present the results of a comparison between the skin of an older and a younger group of volunteers by in vivo histometric measurements.

Topical Activity of Ascorbic Acid: From in vitro Optimization to in vivo Efficacy

We present here a new cosmetic formula system containing 3% ascorbic acid based on an optimized oil-in-water (O/W) emulsion. This formulation demonstrated a good long-term stability of the active ingredient and also of the emulsion itself. It could be deduced from in vitro release studies that this O/W emulsion enabled a better release of the hydrophilic active agent than an alternative W/O emulsion. By measuring the ultraweak photon emission, which is a well-established parameter for the oxidative stress in the skin, the high in vivo antioxidant capacity of 3% ascorbic acid was demonstrated after 1 week of product application. This placebo-controlled study also proved that ascorbic acid in an O/W cream reduced oxidative stress in human skin significantly better than the derivative sodium ascorbyl-2-phosphate, a more stable vitamin C replacement commonly used in cosmetic formulations. With increasing age, the number of papillae in the epidermal-dermal junction zone in human skin are reduced. This implies a possible consequence of reduced mechanical resistance of the skin and impaired supply of the epidermis with nutrients. In a 1-month placebo-controlled study on 25 human volunteers, a significant increase in the number of dermal papillae after application of the 3% ascorbic acid cream was demonstrated, using a confocal laser scanning microscope. Fine lines and wrinkles are a characteristic sign of aged and especially photo-aged skin. Application of 3% ascorbic acid in a 12-week placebo-controlled usage study indicated a significant reduction of facial wrinkles. Altogether, 3% ascorbic acid in a cosmetic O/W emulsion has been shown to be appropriately stable and to enable a good release of the active agent in vitro as a precondition for a high efficacy in vivo. Application in vivo resulted in a significant reduction of oxidative stress in the skin, an improvement of the epidermal-dermal microstructure and a reduction of fine lines and wrinkles in aged skin. These results were received within a relatively short period of time of product application.

Topically applied vitamin C increases the density of dermal papillae in aged human skin

BackgroundThe influence of ageing on the density of the functional entities of the papillae containing nutritive capillaries, here in terms as the papillary index, and the effect of topically applied vitamin C were investigated by confocal laser scanning microscopy (CLSM) in vivo.MethodsThe age dependency of the papillary index was determined by CLSM on 3 different age groups. Additionally, we determined the effect of a topical cream containing 3% vitamin C against the vehicle alone using daily applications for four months on the volar forearm of 33 women.ResultsThere were significant decreases in the papillary index showing a clear dependency on age. Topical vitamin C resulted in a significant increase of the density of dermal papillae from 4 weeks onward compared to its vehicle. Reproducibility was determined in repeated studies.ConclusionsVitamin C has the potential to enhance the density of dermal papillae, perhaps through the mechanism of angiogenesis. Topical vitamin C may have therapeutical effects for partial corrections of the regressive structural changes associated with the aging process.

Histometric data obtained by in vivo confocal laser scanning microscopy in patients with systemic sclerosis.

BackgroundIt would be a benefit if time-saving, non-invasive methods could give hints for diagnosing systemic sclerosis. To investigate the skin of patients with systemic sclerosis using confocal laser scanning microscopy in vivo and to develop histometric parameters to describe characteristic cutaneous changes of systemic sclerosis observed by this new technique, we conducted an exploratory study.Materials and MethodsFifteen patients with systemic sclerosis treated with extracorporal photopheresis were compared with 15 healthy volunteers and 10 patients with other disorders also treated with extracorporal photopheresis. All subjects were investigated using confocal laser scanning microscopy in vivo.ResultsMicromorphologic characteristics of skin of patients with systemic sclerosis and measuring parameters for melanisation, epidermal hypotrophy, and fibrosis for dislocation of capillaries by collagen deposits in the papillary dermis were evaluated. An interesting finding was an increased thickness of the tissue in the dermal papillae superior to the first dermal papilla vessel. It was also possible to reproduce characteristic histologic features by confocal laser scanning microscopy in vivo. Histometric parameters for fibrosis and vascular features developed in this study showed significant differences in patients with systemic sclerosis compared to controls.ConclusionsAlthough the predominant histopathological features in systemic sclerosis are findings of the reticular dermis and the subcutis, and in histopathological investigation the epidermis seems to remain unaffected by the disease, we have demonstrate some characteristic differences in the epidermis and papillary dermis by confocal laser scanning microscopy in vivo. Some of them have not been described so far. However, to use this technique as a tool for diagnosis and/or staging of systemic sclerosis, further studies are needed investigating the sensitivity and specificity of the histometric parameters developed in this study.