The findings improve understanding of normal skin development but could also be useful in treatments for diseases such as psoriasis and non-melanoma skin cancers, which result from abnormal proliferation and maturation of skin cells, say researchers at the Medical College of Georgia in the US.
Glycerin, or glycerol, is a natural alcohol and water attractor that has been used in skincare products for centuries. But the new study, published in the December issue of The Journal of Investigative Dermatology, shows that the substance works as a signal to help direct skin cells through their four normal stages of maturity.
The researchers found glycerol's role in skin cell maturation while studying phospholipase D, an enzyme that converts fats or lipids in the external, protective cell membrane to cell signals. They found that when phospholipase D pairs with glycerol, it produces a distinctive signal that directs skin cell maturation.
"We think the glycerol is serving as a substrate to allow the skin to mature properly and, when you don't have enough glycerol in the skin, cells don't mature properly and that is why you get hyper-proliferative, thick skin," said Dr Wendy Bollinger Bollag, lead researcher and cell physiologist.
She added:"This is a pretty novel hypothesis that is really quite in its infancy."
The researchers tested their theory on a recently developed mouse model, genetically manipulated to lack sufficient glycerol in its skin. When glycerol was given topically or orally to these animals, many of the skin problems resolved. Other water-attracting agents did not work so well, which gives the researchers more fuel for their finding that glycerol also plays a key role in normal skin cell maturation and proliferation.
The researchers are currently trying to find out what the signal activates. "In other words, how does the signal that is produced by phospholipase D and the glycerol actually tell the cell to mature? How does that signal then activate certain enzymes and proteins in the cell to make the cell mature?"
"Other things we are interested in looking at are ways to manipulate the system, for instance to increase signal formation, to see if we can then increase keratinocyte formation and that would potentially be a way to harness the system to treat skin diseases," added Bollag.