Meeting Abstract

P1.120  Monday, Jan. 4  Cutaneous Water Loss and Lipids of the Stratum Corneum in two sympatric species of bats MUNOZ-GARCIA, Agusti*; REICHARD, Jonathan ; RO, Jennifer; WILLIAMS, Joe; KUNZ, Thomas; Ben-Gurion University; Boston University; Ohio State University; Ohio State University; Boston University agustimg@gmail.com

The lipid matrix of the stratum corneum (SC), the outer layer of the epidermis of mammals, constitutes the barrier of water vapor diffusion through the skin. The lipids of the SC are structured in the intercellular spaces of the mammalian epidermis in ordered layers, called lamellae, which prevent water loss. The main lipid classes in the SC of mammals are cholesterol, free fatty acids and ceramides, which form the backbone of lamellae. However, our knowledge on how the lipid composition of the SC alters cutaneous water loss (CWL) in mammals is rudimentary, and derived from studies on laboratory animals and humans. We measured CWL of individuals of two species of sympatric bats, Tadarida brasiliensis and Myotis velifer. We then correlated CWL with the lipid composition of the SC, measured by thin layer chromatography and high-performance liquid chromatography coupled with atmospheric pressure photoionization and mass spectrometry, in the first study of its kind on wild mammals. Surface-specific CWL was higher in Myotis than in Tadarida. Individuals of Tadarida had more classes, and a higher amount, of polar ceramides in the SC, a feature associated with lower CWL in other species of mammals and birds. We conclude that qualitative and quantitative modifications of the lipid composition of the SC led to significant changes in CWL of bats.