The discovery is a potentially big boost to consumers looking for a safe way to tan without exposing themselves to the potentially dangerous risk of exposing themselves to UV rays.
In particular the breakthrough could prove particularly important for individual with naturally lower levels of pigmentation, who are generally more susceptible to developing skin cancers.
Safe tanning
The study, which took place using groups of scientist at the Massachusetts General Hospital and the Dana-Farber Cancer Institute, explains how the scientists have developed a way of increasing pigmentation in human skin, safely.
The study was reported in a recent edition of the journal Cell Reports and showed that the tanning response was induced following topical application of the compound on a strain of mouse that does not have protection from higher levels of melanin pigmentation.
“The activation of the tanning and pigmentation pathway by this new class of small molecules is physiologically identical to UV-induced pigmentation without the DNA-damaging effects of UV,” said David Fisher, the HMS Edward Wigglesworth Professor of Dermatology and chief of the Department of Dermatology at Mass General, who led both studies.
“We need to conduct safety studies, which are always essential with potential new treatment compounds, and better understand the actions of these agents. But it’s possible they may lead to new ways of protecting against UV-induced skin damage and cancer formation.”
Building on a body of research
The research builds on a previous study led by Fisher that used a topical compound called forskolin on a strain of red-haired mice with lower levels of melanin pigmentation.
The forksolin works by activating a protein further down the pigmentation pathway, bypassing the interruption and inducing production of the protective dark pigmentation called eumelanin.
Subsequent experimentation on human skin showed that it did not have the same successful results, but the scientists believe that this is because human skin is about five times thicker than that of the mice used in the experiment.
This led the scientists down a different path, using enzymes called salt-inducible kinases (SIKs) that are known to regulate transcription of a protein even further down the pigmentation pathway, while experiments by scientists in Japan had shown inhibiting SIK expression to activate pigmentation in mice.
Solving skin penetration issues
However, this compound still proved to have a limited activity in human skin samples, thought to be due to issues with penetration, so the Harvard researchers turned to a new class of small-molecule SIK inhibitors that were found to have a higher level of skin penetration.
Microscopic examination of the samples showed that eight days after administration, eumelanin pigment was produced and deposited near the skin’s surface in patterns typified by UV-induced tanning.
“We are excited about the possibility of inducing dark pigment production in human skin without a need for either systemic exposure to a drug or UV exposure to the skin,” Fisher said.