Skins prone to sunburn may be capable of a normal tan

Scientists have always assumed that the propensity of redheads to burn is related to their inability to make melanin -- the pigment which is created and stored in our skin cells to protect us against the sun's ultra-violet radiation (UVR).

But a team from the University's Centre for Skin Sciences (CSS) found that in the laboratory, pigment cells isolated from very fair (Celtic-type) skin were able to make as much -- and in one case up to five times more -- melanin than cells from olive (Italian-type) skin, when cultured under identical conditions. However, the fair skin cells did show a higher inflammatory response to UVR than their olive-skinned counterparts. The research, in part funded by the Wellcome Trust, is published in the current issue of Pigment Cell and Melanoma Research.

CSS Director and the study's lead author, Professor of Cell Biology Des Tobin, says: "Research into sunburn has tended to ignore melanocytes -- the cells that make melanin -- as it's been assumed that was all they did. But our research has shown that in some skin types they also contribute to the inflammation that creates sunburn and it's this, rather than their ability to make melanin, that seems to be at the root of how different skins respond to the sun."

The researchers isolated melanocytes from five patients with very fair skin and from five with olive skin. Some of the cells from each patient were stimulated to create melanin and the levels measured. Others cells from each patient were subjected to UVR and levels of a pro-inflammatory chemical called prostaglandin-E₂ (PGE₂) measured. All the cells were able to make similar amounts of melanin, with one fair skinned patient making five times more than the other patients. However, melanocytes from patients with very fair skins made up to five times more PGE₂ than those from olive-skinned patients.

"Our research shows that melanocytes may play a role in UVR-induced inflammation, so targeting these cells with anti-inflammatory interventions could offer a new way of protecting more vulnerable skin types from sunburn," says Professor Tobin. "Clearly something within fair skins is also preventing melanocytes from making protective melanin to prevent the harm caused by UVR and we will be focusing further research on this area."