title: Dietary docosahexaenoic acid in combination with arachidonic acid ameliorates allergen-induced dermatitis in mice.
abstract: OBJECTIVE
  In this study, we investigated the impact of dietary docosahexaenoic (DHA) and arachidonic acid (AA) on development and severity of allergen-induced dermatitis.
  
  
  METHODS
  In sensitized mice, skin inflammation was induced by ovalbumin. Mice received either a diet containing 0.015% DHA, 0.029% AA or the combination of both. The severity of dermatitis was evaluated by using a clinical skin score (CSS), followed by immunohistologic and cytokine analysis. To unravel potential mechanisms, interleukin (IL)-4 or tumor necrosis factor α-stimulated keratinocytes from the cell line Kera-308 was cultured with different DHA/AA compositions and analyzed regarding proliferation and cytokine production.
  
  
  RESULTS
  Dietary DHA/AA significantly improved the severity of allergen-induced dermatitis as the CSS was reduced by 36 ± 23% (p=0.005). Furthermore, reduced epidermal KI67 expression, increased number of forkhead box P3(+) cells, and elevated IL-10 expression were determined in skin lesions of dietary-treated mice. Correspondingly, in vitro DHA/AA-treated keratinocytes exhibited increased IL-10 expression and produced less thymic stromal lymphopoietin.
  
  
  CONCLUSIONS
  Dietary DHA/AA supplementation leads to a significant amelioration of allergen-induced dermatitis. This was accompanied with the presence of increased regulatory T cells and IL-10 expression in lesional skin. Moreover, we identify keratinocytes, which play a crucial role in the regulation of skin inflammation, as important targets of DHA/AA supplementation. Future studies are needed to clarify whether DHA/AA acts directly or whether its biologic active metabolites are responsible for these findings. This may unravel novel therapeutical compounds for allergen-induced dermatitis.
authors.affiliation: Allergy-Center-Charité, Department of Dermatology and Allergy, Charité-Universitätsmedizin Berlin, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Weise
authors.forename: Carolin
authors.initials: C
authors.lastname: Heunemann
authors.forename: Christoph
authors.initials: C
authors.lastname: Loddenkemper
authors.forename: Udo
authors.initials: U
authors.lastname: Herz
authors.forename: Eric A F
authors.initials: EA
authors.lastname: van Tol
authors.forename: Margitta
authors.initials: M
authors.lastname: Worm
mesh_terms: D000485:Allergens / Q000009:adverse effects / Q000276:immunology; D000818:Animals; D016718:Arachidonic Acid / Q000008:administration & dosage* / Q000494:pharmacology; D002460:Cell Line; D003876:Dermatitis, Atopic / Q000178:diet therapy* / Q000209:etiology / Q000276:immunology / Q000503:physiopathology; D004035:Diet Therapy / Q000379:methods; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage* / Q000494:pharmacology; D004359:Drug Therapy, Combination; D005260:Female; D015603:Keratinocytes / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D012720:Severity of Illness Index; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D016896:Treatment Outcome
chemical_list: D000485:Allergens; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid