title: The effect of epidermal levels of urocanic acid on 25-hydroxyvitamin D synthesis and inflammatory mediators upon narrowband UVB irradiation.
abstract: OBJECTIVE
  Urocanic acid (UCA) absorbs ultraviolet (UV)B radiation in the epidermis which may interfere with phototherapy. Therefore, the influence of individual levels of UCA on immune reactivity and vitamin D synthesis induced by narrowband UVB radiation was assessed.
  
  
  METHODS
  Twenty-eight subjects with irritant contact dermatitis of the hands were irradiated with suberythemal doses of narrowband UVB radiation on their unaffected lower forearms on three consecutive days. Stratum corneum tape strips and epidermal interstitial fluid (ISF) as well as blood samples were analyzed.
  
  
  RESULTS
  Narrowband UVB irradiation led to the conversion of trans-UCA into its cis-isomer in the epidermis. The observed increase in 25-hydroxyvitamin D serum concentrations was inversely correlated with the baseline levels of trans-UCA. Furthermore, UVB irradiation induced significant changes in the levels of CXCL10/IP-10, CCL2/MCP-1, CCL4/MIP-1β, and the IL-1RA/IL-1α ratio. The levels of IL-1α and CXCL9/MIG showed a trend toward increase. The changes in the levels of inflammatory and immunomodulatory mediators did not depend on baseline levels of trans-UCA.
  
  
  CONCLUSIONS
  The results suggest that epidermal levels of trans-UCA affect vitamin D synthesis, but not cutaneous immune reactivity upon repeated exposure to suberythemal doses of narrowband UVB radiation. However, this requires further exploration.
authors.affiliation: Department of Dermatology, Environmental Medicine and Health Theory, University of Osnabrück, Osnabrück, Germany.|Department of Dermatology, Ernst von Bergmann General Hospital, Teaching Hospital Charité University Medicine Berlin, Potsdam, Germany.
authors.forename: Lilla
authors.initials: L
authors.lastname: Landeck
authors.affiliation: Laboratory for Analytical Chemistry, Department of Chemistry and Biochemistry, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia.
authors.forename: Ivone
authors.initials: I
authors.lastname: Jakasa
authors.affiliation: Laboratory for Analytical Chemistry, Department of Chemistry and Biochemistry, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia.
authors.forename: Irena
authors.initials: I
authors.lastname: Dapic
authors.affiliation: Departments of Respiratory Medicine and Experimental Immunology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: René
authors.initials: R
authors.lastname: Lutter
authors.affiliation: Department of Dermato-Allergology, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
authors.forename: Jacob P
authors.initials: JP
authors.lastname: Thyssen
authors.affiliation: Department of Dermato-Allergology, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
authors.forename: Lone
authors.initials: L
authors.lastname: Skov
authors.affiliation: Department of Dermatology, Venereology, and Allergology, University Medical Center Göttingen, Georg August University, Göttingen, Germany.|Lower Saxony Institute of Occupational Dermatology, University of Osnabrück and University Medical Center Göttingen, Osnabrück/Göttingen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Braun
authors.affiliation: Department of Dermatology, Venereology, and Allergology, University Medical Center Göttingen, Georg August University, Göttingen, Germany.|Lower Saxony Institute of Occupational Dermatology, University of Osnabrück and University Medical Center Göttingen, Osnabrück/Göttingen, Germany.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Schön
authors.affiliation: Department of Dermatology, Environmental Medicine and Health Theory, University of Osnabrück, Osnabrück, Germany.|Lower Saxony Institute of Occupational Dermatology, University of Osnabrück and University Medical Center Göttingen, Osnabrück/Göttingen, Germany.
authors.forename: Swen M
authors.initials: SM
authors.lastname: John
authors.affiliation: Coronel Institute for Occupational Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Sanja
authors.initials: S
authors.lastname: Kezic
authors.affiliation: Department of Dermatology, Environmental Medicine and Health Theory, University of Osnabrück, Osnabrück, Germany.|Lower Saxony Institute of Occupational Dermatology, University of Osnabrück and University Medical Center Göttingen, Osnabrück/Göttingen, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Brans
mesh_terms: D000293:Adolescent; D000328:Adult; D018925:Chemokines / Q000378:metabolism; D003877:Dermatitis, Contact / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy*; D004817:Epidermis / Q000378:metabolism* / Q000473:pathology; D005260:Female; D000091344:Filaggrin Proteins; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000378:metabolism; D053582:Interleukin-1alpha / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D014466:Ultraviolet Rays; D014467:Ultraviolet Therapy; D014560:Urocanic Acid / Q000378:metabolism*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D018925:Chemokines; C000717249:FLG protein, human; D000091344:Filaggrin Proteins; C508584:IL1A protein, human; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D053582:Interleukin-1alpha; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D014560:Urocanic Acid
keywords: cytokine; filaggrin; narrowband ultraviolet B; urocanic acid; vitamin D