Skin Lipid Composition Varies Based on Clinical Subphenotypes in Adult European American Atopic Dermatitis Subjects
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Arup K Indra, Professor, Shan Li, Miguel Villarreal, Denise C. Babineau, PhD, Catherine Philpot, Gloria David, PhD, Mark Boguniewicz, MD FAAAAI, Jon M. Hanifin, MD FAAAAI, Donald Y.M. Leung, MD PhD FAAAAI, Eric L Simpson, MD, MCR, Lisa A. Beck, MD FAAAAI
Rationale: Atopic dermatitis (AD) is an inflammatory skin condition with well-recognized subphenotypes distinguished by physiological measures of skin barrier function and status of S. aureus colonization. Skin lipid compositions are altered in AD subjects. Our objective was to determine whether lipid endophenotypes of the stratum corneum associate with the clinical AD subphenotypes of S. aureus colonized or barrier disrupted.

Methods: One NIAID-funded AD Research Network site enrolled 27 AD and 15 non-atopic (NA) adult subjects (≥18 y). AD subjects were subphenotyped as ADStaph+ if they grew S. aureusfrom skin swabs obtained at lesional or nonlesional sites, while ADStaph- and all NA subjects had no growth. Skin barrier function was assessed by transepidermal water loss (TEWL) measurements of nonlesional upper extremity skin. Tape stripping adjacent to site of TEWL measurements was performed for one-step lipid extraction and lipidomics analyses using modified UP-LC methodology.

Results: Significant decreases in the long-chain ceramide species, CER[AH] C48 in ADStaph+ compared to ADStaph- (7883 vs. 13798, P=0.035) subjects were observed. Similar reductions in the long-chain triglyceride TG 48:2 were observed in the ADStaph+ patients compared to ADStaph- (15815 vs. 35179, P=0.008). The decrease in long-chain CER[AH]C48 also correlated with increased basal TEWL[g/m2h; (P<0.05)] in ADStaph+ and ADStaph- subjects.

Conclusions: S. aureus colonization in AD correlates with a deficiency in long-chain lipid species. The lipid species identified in our study may play a role in barrier homeostasis and antimicrobial defense. Altered epidermal lipid composition can contribute to barrier disruption and susceptibility to S. aureus colonization in AD.