Sweat lipid mediator profiling: a noninvasive approach for cutaneous research

Oleocanthal-rich extra virgin olive oil demonstrates acute anti-platelet effects in healthy men in a randomized trial

“…Extracts were concentrated and reconstituted in internal standard solution prior to analysis. Analytical targets were separated on a 2.1 × 150 mm, 1.7 µm BEH C18 column (Waters; Milford, MA) and detected by negative mode electrospray ionization and tandem mass spectrometry on a 4000 QTRAP ® (Sciex; Framingham, MA) as previously described (Agrawal et al, 2017). Calibrants and internal standards were purchased from Cayman Chemical (Ann Arbor, MI), Avanti Polar Lipids Inc. (Alabaster, AL), and Larodan Fine Lipids (Malmo, Sweden).…”

Noninvasive profiling of sweat‐derived lipid mediators for cutaneous research

“…The formation and biological roles of these lipid mediator classes have been reviewed elsewhere and are beyond the scope of this manuscript (13, 16, 17). The abbreviations used to describe the oxylipins, endocannabinoids, sphingoid bases, and ceramides mentioned in this manuscript follow standard conventions in the field, and are described and expanded elsewhere (18, 19). …”

“…Specific evidence of lipid mediator cross-talk can be found in the interconversion of lipid mediator classes, such as the conversion of 2-AG to PGE2 1-glycerol by COX-2 (22); or inhibition or enhancement of lipid mediator forming enzyme activity by other lipid mediators, such as the inhibition of COX-2 activity by 2-AG or modulation of phospholipase A2 and COX-2 activity by sphingolipids (23, 24). While previously available technology did not permit simultaneous analysis of multiple lipid mediator classes, more recent advances allow (for example) the analysis of oxylipins, endocannabinoids and ceramides from a single sample extract (18, 25). These advances should be taken advantage of in future studies that seek to examine the lipid mediator profile of a cutaneous disease, particularly as often inhibition of one lipid mediator may lead to downstream effects on other lipid mediator classes relevant to that disease, which may not be readily detected if only a single lipid mediator class is analyzed.…”

“…To date, few studies that have attempted to normalize sweat analyte concentrations using detected sweat electrolyte levels (81, 82). Chemical isotope labelling of sweat patches has been proposed as an alternative normalization strategy (83), and it may also be possible to normalize to the sample volume if a liquid sweat sample can be collected and the entire sample is analyzed (18). Sample normalization for sweat remains an area to be fully characterized in order to more develop standardized quantitative approaches.…”

“…In an effort to more comprehensively characterize the sweat lipid mediator profile and understand its utility in cutaneous research, we recently attempted study in which we assayed eccrine sweat collected from the volar forearm of individuals with and without atopic dermatitis for over 150 lipid mediators to find differences between the groups (18). Fifty-eight lipid mediators were quantified in the collected sweat, including polyunsaturated fatty acid-derived alcohols, diols, epoxides and ketones; prostaglandins; nitrolipids; endocannabinoids; ceramides; and sphingosines, and the sweat of individuals with atopic dermatitis was shown to contain increased concentrations of [NS] and [NdS] ceramides compared to controls (18).…”