Japan : Kao HSS helps in skin color determination

Kao Biological Science Laboratories, a subsidiary of Kao Corporation (president and CEO: Motoki Ozaki), working with the University of Cincinnati and Cincinnati Children’s Hospital Research Foundation, both of Ohio, USA, has discovered that the keratinocytes, one of the cell types in human skin, affect color formation in the skin, along with the melanocytes, another cell type that is already known to produce the skin color pigment melanin.
This finding, together with detailed results of the research work, appeared in the September 2007 edition of The FASEB Journal, published by the Federation of American Societies for Experimental Biology.
Based near Washington, DC, FASEB is a non-profit advocate of policies that promote scientific progress and education and lead to improvements in human health.
The Kao researchers looked into the essential formation of human skin and questioned how skin color is determined. They focused on the cell types in the epidermis — comprised of keratinocytes and a few bottom-layer melanin-producing melanocytes — in order to understand their various roles in color determination.
The work entailed the creation of human skin substitutes (HSS), or chimeric skin, to isolate and test the differing cell types. Cell combinations that do not occur naturally were among the HSS samples.
The principal finding about the color-determining role played by keratinocytes was reached by comparing the behavior of different HSS samples. Comparisons revealed a key fact: keratinocytes in naturally dark skin have a greater capacity to darken skin than those in naturally light skin.

More specifically, HSS combining (melanin-producing) melanocytes from naturally dark skin with keratinocytes from naturally dark skin produces more melanin on the surface of the skin than HSS combining melanocytes from naturally dark skin with keratinocytes from naturally light skin.
This discovery raises the possibility of skin color control via the keratinocytes, which are more numerous (comprising 96% of the epidermis) and more accessible (occupying the surface layers) than melanocytes.
It is expected that the research findings will be applied in developing skin-lightening and tanning products, with the goal of attaining a youthful and attractive appearance through controlled skin color.