TY - JOUR
T1 - The importance of the depth distribution of melanin in skin for DNA protection and other photobiological processes
AU - Nielsen, Kristian P.
AU - Zhao, Lu
AU - Stamnes, Jakob J.
AU - Stamnes, Knut
AU - Moan, Johan
PY - 2006/3/1
Y1 - 2006/3/1
N2 - Melanin pigments are important regulators for the evolution of essential functions of human skin. The concentration of melanin, as well as its depth distribution, is strongly affected by ultraviolet radiation. In un-tanned skin, melanin pigments are found only in the basal layer of the epidermis, while in tanned skin it is distributed throughout the epidermis. So far, mainly the amount of melanin, and not its distribution, has been considered in view of skin photobiology. With an advanced radiative transfer model we investigate, for the first time, how the depth distribution of melanin influences the amount of ultraviolet radiation that reaches living cells in the epidermis, and thus can damage the DNA in the cells. The simulations are performed for averagely pigmented skins (type III-IV). A surprisingly large factor, up to 12, is found between the ultraviolet protection of skin with melanin distributed throughout the epidermis, and skin with melanin only in the basal layer of the epidermis. We also show that the synthesis of previtamin D3, in skin, can vary with more than 100% if the depth distribution of melanin is changed, while the degradation of folate in dermal blood is almost un-affected by variations in the melanin depth distribution.
AB - Melanin pigments are important regulators for the evolution of essential functions of human skin. The concentration of melanin, as well as its depth distribution, is strongly affected by ultraviolet radiation. In un-tanned skin, melanin pigments are found only in the basal layer of the epidermis, while in tanned skin it is distributed throughout the epidermis. So far, mainly the amount of melanin, and not its distribution, has been considered in view of skin photobiology. With an advanced radiative transfer model we investigate, for the first time, how the depth distribution of melanin influences the amount of ultraviolet radiation that reaches living cells in the epidermis, and thus can damage the DNA in the cells. The simulations are performed for averagely pigmented skins (type III-IV). A surprisingly large factor, up to 12, is found between the ultraviolet protection of skin with melanin distributed throughout the epidermis, and skin with melanin only in the basal layer of the epidermis. We also show that the synthesis of previtamin D3, in skin, can vary with more than 100% if the depth distribution of melanin is changed, while the degradation of folate in dermal blood is almost un-affected by variations in the melanin depth distribution.
KW - Efficiency spectra
KW - Human photophysiology
KW - Melanosomes
KW - Radiative transfer modelling
UR - http://www.scopus.com/inward/record.url?scp=32644438237&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=32644438237&partnerID=8YFLogxK
U2 - 10.1016/j.jphotobiol.2005.11.008
DO - 10.1016/j.jphotobiol.2005.11.008
M3 - Article
C2 - 16388960
AN - SCOPUS:32644438237
SN - 1011-1344
VL - 82
SP - 194
EP - 198
JO - Journal of Photochemistry and Photobiology B: Biology
JF - Journal of Photochemistry and Photobiology B: Biology
IS - 3
ER -