As overt infection in the skin is a rare event, researchers have theorized that AMPs must not only help fight infection, but play a role in preventing infection from developing in the first place. In a study appearing online on June 15 in advance of print publication in the July issue of the Journal of Clinical Investigation, Ole Sorensen and colleagues from Lund University, Sweden, investigated what triggers AMP production in human skin. Interestingly, they found that AMPs were produced in human skin after sterile wounding of the skin surface, illustrating that exposure to invading microbes is not the sole trigger for the immune response in skin.
The authors went on to show that AMP was produced through activation of the epidermal growth factor receptor (EGFR), which is known to play a role in the normal wound-healing process. The authors found that the antibacterial activity of the skin against the potential skin pathogen Staphylococcus aureus was increased by activation of EGFR, and that the concentrations of AMPs in the epidermis of wounded skin exceeded those necessary to suppress or prevent the growth of foreign microbes. The results of this study demonstrate that wounding of the skin alone, without the presence of microbes, is sufficient to activate defense mechanisms in the skin that can prevent microbial growth and related harmful skin infections.