Philip W. Wertz
University of Iowa College of Dentistry
USA
Title: Antimicrobial lipids at the skin surface
Biography
Biography: Philip W. Wertz
Abstract
The skin surface represents our interface with the external environment, and as such, is our first line of defense against microbial colonization and infection. Lipids at the skin surface are thought to underlie at least part of an antimicrobial barrier. The skin surface is coated with sebaceous lipids, including lauric acid (C12:0) and sapienic acid (C16:1Δ6), both of which are uniquely potent antimicrobial agents. The free fatty acids are produced through the action of lipase(s) on sebaceous triglycerides. In addition, the stratum corneum contains antimicrobial free long-chain bases, sphingosine and dihydrosphingosine. The long-chain bases are thought to be produced through the action of ceramidases on ceramides near the skin surface. These antimicrobial lipids have been shown to kill a range of Gram-positive and Gram-negative bacteria, including Staphylococcus aureus that is resistant to both methicillin and mupirocin. Furthermore, some of these lipids have been found to act synergistically with ethanol and with the antimicrobial peptide LL37. In fact, sapienic acid, with or without a low concentration of ethanol, was more effective than mupirocin. These lipids are thought to be part of the innate immune system of the skin. The possibility exists that topical formulations of these lipids could be used prophylactically to prevent infections in susceptible individuals, such as the elderly or people with atopic dermatitis. Such formulations could also be used to treat active infections.
