Your skin is coated with acid. While that might sound disturbing, the mild acidity of the skin's surface actually helps to maintain the strength and cohesiveness of the skin. Now researchers at SFVAMC have discovered where this acidity comes from, and they suggest how it may help to hold the skin together.
The findings, published in the latest issue of the Journal of Investigative Dermatology, may be used to develop therapies for skin problems such as psoriasis.
For decades scientists have known that the outer layers of the skin are about as acidic as a bowl of crushed tomatoes. This acidity was believed to help ward off infections by preventing the growth of bacteria. But the source of all this acid and how it helped to maintain the skin's strength and integrity, remained a mystery.
In their latest study, Joachim Fluhr, MD, a postdoctoral research fellow at the SFVAMC and UCSF, and his colleagues lead by SFVAMC dermatologist Peter Elias, MD, a UCSF professor of dermatology, tested the hypothesis that the acid is produced when enzymes break down fat-like molecules in skin cells, called phospholipids, into smaller acid-tipped fat molecules called fatty acids.
To test this theory, the researchers used a hairless breed of mice and treated patches of their skin with a chemical that blocks the conversion of phospholipids to fatty acids. They then observed what effect this treatment had on the skin.
The treated skin quickly lost its acidity, and this change also had a negative effect on the skin's integrity, Fluhr said. Treated patches of skin were more susceptible to evaporation and drying than untreated skin, he said.
Furthermore, the reduced acidity also made the skin less cohesive. When the researchers repeatedly applied strips of adhesive tape to the skin, they found that significantly more protein stuck to the tape from the inhibitor treated skin than from normal skin.