Penetration of topically applied cosmetic products / ingredients

Pigmentation (tanning) is a defence mechanism used by skin to protect itself from excessive sun exposure. Skin thickening or hyperkeratosis is also due to an adaption caused by increased UV exposure. This can result in inflammation and keratitis, sunburn, as well as an amitosis inhibition.

Epidermal changes such as epidermal hyperplasia, especially increased thickness (acanthosis) of the stratum corneum, were observed numerous times after artificial or natural UV exposure. However, in vivo examinations of skin are not possible with standard histological methods. The skin trauma caused by tissue excision and the artefact effects of preparing the specimens make a comparison with living skin impossible.

Confocal laser scanning microscopy, however, is able to generate high-contrast images of different epidermis layers and papillary dermis in vivo and non-invasively. Especially the stratum basale and the stratum spinosum are depicted well due to their high content of melanin and keratin. Thickness changes are easily visible and can be recorded quantitatively by creating confocal image sequences with high chronological resolution. The extent of photoadaptive processes can thereby be assessed reliably.

The quantification software ConfoScan specifically designed for quantifying the images created with VivaScope is able to determine the thickness of the epidermis exactly.  Three-dimensional depictions of the stratum corneum or the papillae, for example, will soon be possible as well and easy to realize.

[1] Huzaira M, Rius F, Rajadhyaksha R, Anderson RR, Gonsález S: “Topographic variations in normal skin, as viewed by in vivo reflectance confocal microscopy.” J Invest Dermatol. 2001; 116(6): 846-52.
[2] Kolbe L, Kligman AM, Schreiner V, Stoudemayer T: “Corticosteroid-Induced Atrophy and Barrier Impairment Measured by Non-Invasive Methods in Human Skin.” Skin Res Technol. 2001: 7(2): 73-7.

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