Serum endocannabinoids and N-acyl ethanolamines and the influence of simulated solar UVR exposure in humans in vivo

Abstract

Solar ultraviolet radiation (UVR) exposure of human skin has beneficial and harmful effects on health, including impact on immune function, inflammation and reportedly mood, but these are not fully elucidated. Since the endocannabinoid system is implicated in many activities including mood alteration, our objective was to (i) determine and quantify circulating levels of a wide range of endocannabinoid and N-acyl ethanolamine (NAE) species (ii) evaluate whether these are modulated by cutaneous UVR exposures, as attained through repeated low level summer sunlight exposure. Wearing goggles to prevent eye exposure, 16 healthy volunteers (23-59y; 10 light skin, phototype II, and 6 dark skin, phototype V) received the same UVR exposures (1.3 SED, 95%UVA/5% UVB) thrice weekly for 6 weeks, whilst casually dressed to expose ~35% skin surface area. Blood samples were taken at baseline, days 1, 3 and 5 of week one, then at weekly intervals, and analysed by LC-MS/MS. Eleven endocannabinoids and NAEs were detected and quantified at baseline, with Npalmitoyl ethanolamine the most abundant (30% of total). Levels did not vary according to phototype (p>0.05), except for the NAE docosapentaenoyl ethanolamide, which was higher in phototype II than V (p=0.0002). Level of the endocannabinoid, 2-AG, was elevated during the UVR exposure course (p<0.05 vs baseline for all subjects; p<0.01 for each phototype group), with maximum levels reached by week 2-3, while NAE species did not significantly alter. These findings suggest differential involvement of the cutaneous endocannabinoid system in low dose solar UVR responses in humans.3

Is Sunlight Exposure Enough to Avoid Wintertime Vitamin D Deficiency in United Kingdom Population Groups?

“…Recently, studies in humans in vivo showed that exposure to UVR (5% UVB, 95% UVA) modulated the cutaneous endocannabinoid system [31], while exposure to UVA radiation (315–400 nm) reduced blood pressure [32]. Further studies are required to assess the impact of sun exposure on these and further potential health benefits beyond vitamin D synthesis, while the latter is the current established benefit and hence the focus of this work.…”

Circulating Endocannabinoids: From Whence Do They Come and Where are They Going?

“…For example, both 2-AG and AEA are folds-higher in the serum of patients with endotoxic shock than control serum (Wang et al, 2001). Circulating endocannabinoids are increased in patients with cirrhosis (Fernandez-Rodriguez et al, 2004); chronic hepatitis C infection (Patsenker et al, 2015); exposure to solar ultraviolet radiation (Felton et al, 2017); congestive heart failure (Weis et al, 2010b); and atherosclerosis (Maeda et al, 2009). Similarly, rats with acute pancreatitis also exhibit significantly elevated circulating AEA concentrations, particularly in animals with a severe, necrotizing pancreatitis (Matsuda et al, 2005).…”

Pharmacological tools to mobilise mesenchymal stromal cells into the blood promote bone formation after surgery

“…Bone marrow flush (pool of three mice) was processed in order for the extraction of endocannabinoids and N-acyl ethanolamines. 46,47 Samples were analysed on a triple quadrupole mass spectrometer (Xevo TQ-S, Waters) with electrospray ionisation probe coupled to an ultra-high performance liquid chromatography pump (UPLC, Acquity, Waters) (UPLC-MS/MS; the analytes were quantified via multiple reaction monitoring assays using deuterated internal standards and internal calibration lines. Details concerning extraction and analysis can be found in the Supplementary Methods.…”