Scientists believe that fair-skinned people -- mostly those with red hair -- cannot tan properly because of a defect in receptors on the surface of pigment-producing skin cells. The defect leads to decreased production of the chemical cAMP, which stimulates the skin cells to produce pigment. This means that pale-skinned people tend to burn rather than tan, which can lead to skin cancer. The World Health Organization estimates that roughly 60,000 people worldwide die from skin cancer resulting from overexposure to the sun.
Researchers from the Dana-Farber Institute and Children's Hospital Boston created a cream that has not yet been tested on humans, but could be capable of switching on the tanning mechanism in skin cells without exposure to sunlight. The cream contains a molecule that mimics the process that occurs when skin is exposed to ultraviolet sunlight.
The study authors' genetically engineered, fair-skinned mice did not tan when exposed to low levels of UV radiation, but burned when exposed to high UV levels. The mice were treated with the cream -- a compound called forskolin derived from an Indian plant -- which increased cAMP levels in the skin of the mice. The cream caused the mice to tan, and in subsequent testing, the cream-induced tans were indistinguishable from the tans of mice that tanned naturally.
Lead researcher Dr. David Fisher says forskolin treatments could someday help fair-skinned people get tans without overexposure to the sun, which he says "undoubtedly contribute significantly to high skin cancer incidence."
Fisher says more research is needed to determine if the forskolin cream can penetrate deeply enough in human skin to activate the tanning mechanism.
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