title: Can skin exposure to sunlight prevent liver inflammation?
abstract: Liver inflammation contributes towards the pathology of non-alcoholic fatty liver disease (NAFLD). Here we discuss how skin exposure to sunlight may suppress liver inflammation and the severity of NAFLD. Following exposure to sunlight-derived ultraviolet radiation (UVR), the skin releases anti-inflammatory mediators such as vitamin D and nitric oxide. Animal modeling studies suggest that exposure to UVR can prevent the development of NAFLD. Association studies also support a negative link between circulating 25-hydroxyvitamin D and NAFLD incidence or severity. Clinical trials are in their infancy and are yet to demonstrate a clear beneficial effect of vitamin D supplementation. There are a number of potentially interdependent mechanisms whereby vitamin D could dampen liver inflammation, by inhibiting hepatocyte apoptosis and liver fibrosis, modulating the gut microbiome and through altered production and transport of bile acids. While there has been a focus on vitamin D, other mediators induced by sun exposure, such as nitric oxide may also play important roles in curtailing liver inflammation.
authors.affiliation: Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, Western Australia 6008, Australia. shelley.gorman@telethonkids.org.au.
authors.forename: Shelley
authors.initials: S
authors.lastname: Gorman
authors.affiliation: Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, Western Australia 6008, Australia. lucinda.black@telethonkids.org.au.
authors.forename: Lucinda J
authors.initials: LJ
authors.lastname: Black
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD, UK. M.Feelisch@soton.ac.uk.
authors.forename: Martin
authors.initials: M
authors.lastname: Feelisch
authors.affiliation: Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, Western Australia 6008, Australia. prue.hart@telethonkids.org.au.
authors.forename: Prue H
authors.initials: PH
authors.lastname: Hart
authors.affiliation: University of Edinburgh, MRC Centre for Inflammation Research, Edinburgh, EH16 4TJ, UK. richard.weller@ed.ac.uk.
authors.forename: Richard
authors.initials: R
authors.lastname: Weller
mesh_terms: D006370:Heliotherapy; D006505:Hepatitis / Q000517:prevention & control*; D006801:Humans; D065626:Non-alcoholic Fatty Liver Disease / Q000628:therapy*; D012867:Skin / Q000528:radiation effects*; D013472:Sunlight; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D