Non-invasive profiling of sweat-derived lipid mediators for cutaneous research

Authors: AGRAWAL, KARAN - University Of California, Davis; SIVAMANI, RAJA - University Of California, Davis; Newman, John

Submitted to: Skin Research and Technology
Publication Type: Review Article
Publication Acceptance Date: 6/23/2018
Publication Date: 7/21/2018
Citation: Agrawal, K., Sivamani, R., Newman, J.W. 2018. Non-invasive profiling of sweat-derived lipid mediators for cutaneous research. Skin Research and Technology. 58:188-195. https://doi: 10.1194/jlr.M071738.
DOI: https://doi.org/10.1194/jlr.M071738

Interpretive Summary: Recent increases in the use of non-invasive matrices for biomedical analysis as a means to improve subject compliance has led to interest in the evaluation of sweat for both clinical and research applications. However, despite being one of the two main cutaneous secretions, few studies have analyzed sweat in the context of cutaneous disease. This review makes the case for an increased use of sweat in cutaneous research, while discussing lipid mediators of biological processes including cell growth, inflammation, and skin barrier function as potential analytical targets in this matrix. Like urine, sweat is thought to receive inputs both from the surrounding tissue of the sweat gland (i.e. the skin) as well as from the systemic blood stream. Therefore, sweat has the potential to reflect both local and systemic biochemical changes in response to diet, disease or intervention. Additionally, as a non-invasive and non-destructive matrix, sweat is suited for repeated temporal sampling, giving it utility in understanding the rates at which ingested or injected substances can reach and thus influence the skin. Practical considerations of sweat sampling and analysis are also discussed as a way of highlighting the stability and variability of sweat metabolites and their suitability as biomarkers, and suggestions are provided for the normalization of sweat composition across studies. Finally, recent studies involving the analysis of sweat lipid mediators are discussed to demonstrate their utility as analytes to support future cutaneous research studies.

Technical Abstract: Recent increases in the use of non-invasive matrices for biomedical analysis as a means to improve subject compliance has led to interest in the evaluation of sweat for both clinical and research applications. However, despite being one of the two main cutaneous secretions, until very recently, only one study actually analyzed sweat in the context of cutaneous disease. This review attempts to make the case for increased use of sweat in cutaneous research, and discusses lipid mediators as potential analytical targets in sweat given their previous associations with cutaneous disease from skin biopsy studies. As a matrix receiving input from both the systemic circulation and surrounding cutaneous tissue, sweat has the potential to reflect both local and systemic biochemical changes in response to disease or intervention. Additionally, as a non-invasive and non-destructive matrix, sweat is suited for repeated temporal sampling, giving it utility in pharmacokinetic or fluxomic investigations of skin biology. Practical considerations of sweat sampling and analysis are also discussed as a way of highlighting the stability and variability of sweat metabolites and their suitability as biomarkers, and suggestions are provided for the normalization of sweat composition across studies. Finally, recent studies involving the analysis of sweat lipid mediators are discussed to demonstrate their utility as analytes to support future cutaneous research studies.