Effect of oral eicosapentaenoic acid on epidermal Langerhans cell numbers and PGD₂ production in UVR‐exposed human skin: a randomised controlled study

Abstract

28Langerhans cells (LC) are sentinels of skin's immune system, their loss from epidermis 29 contributing to UVR-suppression of cell mediated immunity (CMI). Omega-3 polyunsaturated 30 fatty acids can show potential to abrogate UVR-suppression of CMI in mice and humans, 31 potentially through modulation of LC migration. Our objectives were to examine if 32 eicosapentaenoic acid (EPA) ingestion influences UV-mediated effects on epidermal LC 33 numbers and levels of immunomodulatory mediators including prostaglandin (PG)D 2 , which 34 is expressed by LC. 35In a double-blind randomised controlled study, healthy individuals took 5g EPA-rich 36 (n=40) or control (n=33) lipid for 12-weeks; UVR exposed and unexposed skin samples were 37 taken pre-and post-supplementation. Epidermal LC numbers were assessed by 38 immunofluorescence for CD1a, and skin blister fluid PG and cytokines quantified by LC-39 MS/MS and Luminex assay, respectively. Pre-supplementation, UVR reduced mean (SEM) 40LC number/mm 2 from 913 (28) to 322 (40) (p<0.001), and mean PGD 2 level by 37% from 8.1 41 (11.6) to 5.1 (5.6) pg/µl; p<0.001), while IL-8 level increased (p<0.001). Despite confirmation 42 of EPA bioavailability in red blood cells and skin in the active group, no between-group effect 43 of EPA was found on UVR-modulation of LC numbers, PGD 2 or cytokine levels post-44 supplementation. 45

Cosmetic and Therapeutic Applications of Fish Oil’s Fatty Acids on the Skin

“…Following UV exposure, the loss of this cell in the epidermis is detected [55]. In a double-blind, randomized controlled study of 79 females, Pilkington et al [56] explored the effect of dietary EPA on epidermal Langerhans cells and prostaglandin D2 (PGD2). The healthy volunteers received EPA-rich capsules (5 g EPA) or control lipid (glyceryl tricoprylate caprate) for 12 weeks.…”

Lipidomics for translational skin research: A primer for the uninitiated

“…Solvents are selected based on the chemistry of the lipids being analysed and vary depending on the polarity of the target lipids (this has been reviewed recently). Whilst tape‐stripped stratum corneum and epidermal blister fluid samples can be added directly to solvents, biopsy samples require homogenisation to disrupt the tissue and maximise lipid extraction . Some extraction protocols involve further purification of lipids, such as solid‐phase extraction, methylamine or alkaline hydrolysis, to remove contaminants and reduce matrix effects that can impede the analysis; this is particularly important when targeting lipid species found in low abundance .…”

“…Such low‐abundance, short‐lived lipid mediators are unlikely to be identified by untargeted analyses or lipid imaging, so targeted mass spectrometry remains the most appropriate platform for their analysis. Commercial availability of synthetic standards and deuterated internal standards permits the use of calibration lines for quantitation, and the resulting assays can reveal disease‐ or treatment‐induced changes in specific lipid pathways …”

“…Indeed, DESI‐MSI and MALDI‐MSI studies could be targeted to analyse a selection of lipids identified through UPLC/ESI‐MS/MS or UHPSFC/ESI‐QToF, to investigate whether their distribution throughout the skin changes as well as their abundance, whilst lipid ions identified through lipid imaging could be followed up with more targeted analysis for improved sensitivity. Lipid analysis can reveal diverse information about cutaneous lipid biology, from mechanistic insight into inflammatory skin conditions such as sunburn and irritant dermatitis, to the effects of topical treatments and nutritional supplementation on the skin lipidome, revealing biomarkers, unravelling complex signalling pathways and identifying potential therapeutic targets. As mass spectrometry technology continues to improve, resulting in increased mass accuracy, sensitivity, spatial resolution and more, we expect skin lipidomics to become a routine consideration in the investigation of cutaneous homoeostasis and inflammation.…”

Focus theme issue December 2016: Photobiology & photodermatology

“…The oral administration of omega‐3 polyunsaturated fatty acid (n − 3 PUFA) eicosapentaenoic acid (EPA) showed potential to reduce UV radiation‐induced immune suppression in humans . Pilkington et al . followed this up by investigating whether EPA affects Langerhans cells or cytokines.…”