title: Supplementation with oral probiotic bacteria protects human cutaneous immune homeostasis after UV exposure-double blind, randomized, placebo controlled clinical trial.
abstract: There is now strong evidence that probiotic bacteria can regulate inflammatory immune responses. Here, we analyzed whether oral supplementation with the probiotic bacterial strain Lactobacillus johnsonii (La1) could interfere with skin immune status following UV exposure. A randomized, double-blind, placebo controlled clinical trial was conducted with 54 healthy volunteers receiving either La1 or placebo, during six weeks prior to solar-simulated UV irradiation. Blister roofs and skin biopsies were recovered 1, 4 and 10 days after UV exposure from un-irradiated and irradiated skin and used for immunohistochemical analysis and mixed epidermal cell lymphocyte reaction (MECLR), respectively. La1 supplementation did not prevent the UV-induced phenotypic maturation of Langerhans cells (LCs) or the decrease in MECLR in irradiated skin samples, one day post-irradiation. On day 4, MECLR was still decreased in the placebo group, with a parallel reduction in the CD1a LC marker in irradiated epidermis. In contrast, the allostimulatory capacity of epidermal cells was totally recovered in the La1 group correlating with the normalization of CD1a expression within the epidermis. For the first time, the results provide evidence that ingested probiotic bacteria accelerate the recovery of skin immune homeostasis after UV-induced immunosuppression.
authors.affiliation: Université de Lyon, EA 41-69, Hôpital Edouard Herriot, Pavillon R, Département Dermatologie, Lyon, France. josette.peguet@univ-lyon1.fr
authors.forename: Josette
authors.initials: J
authors.lastname: Peguet-Navarro
authors.forename: Colette
authors.initials: C
authors.lastname: Dezutter-Dambuyant
authors.forename: Timo
authors.initials: T
authors.lastname: Buetler
authors.forename: Jacques
authors.initials: J
authors.lastname: Leclaire
authors.forename: Hans
authors.initials: H
authors.lastname: Smola
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Blum
authors.forename: Philippe
authors.initials: P
authors.lastname: Bastien
authors.forename: Lionel
authors.initials: L
authors.lastname: Breton
authors.forename: Audrey
authors.initials: A
authors.lastname: Gueniche
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D006706:Homeostasis; D006801:Humans; D007778:Lactobacillus; D007801:Langerhans Cells / Q000276:immunology / Q000528:radiation effects; D008297:Male; D019936:Probiotics; D012867:Skin / Q000276:immunology* / Q000528:radiation effects*; D014466:Ultraviolet Rays; D055815:Young Adult