Melanin cells can be formed differently than previously thought, a new study from the Swedish medical university Karolinska Institutet in Stockholm has revealed. These results, which were published in Cell, also indicate the discovery of a new type of stem cell.

A university press release explained that, as is generally known, melanin provides essential protection against UV radiation and it is produced by pigment cells in the skin called melanocytes. According to the established theory, these melanocytes bud off from the spinal cord at an early foetal stage and migrate to the skin where they remain for the rest of their lives. However, scientists at the university have found that most melanocytes actually appear later during foetal development and from an immature cell type that exists in the skin's nerve fibers. These cells, called Schwann cell precursors (SCPs), can also be found in adults.

In addition, the scientists demonstrated how neuronal damage in adults can excite the maturation of melanocytes to form hyperpigmentation around the affected nerves. According to lead researcher Patrik Ernfors, in the report, these findings provide new knowledge about how changes in skin pigmentation occur.

Researchers also described how a change in cell signalling can make the SCP cells develop into pigment cells and argue that SCP cells are really a type of stem cell. According to the report, this work could deepen the understanding of how diseases such as melanoma form.

This research may provide chemists and formulators with a new target to improve sun care protection or self-tanning products that enable the skin's own cells to protect against UV exposure and subsequent skin cancer formation.