title: Antipruritic effects of the probiotic strain LKM512 in adults with atopic dermatitis.
abstract: BACKGROUND
  Evidence suggests that intestinal microbiota play an important role in the pathogenesis of atopic dermatitis (AD) through induction of immunosuppression and immune tolerance; however, the exact underlying mechanism is unclear. Few studies to date have examined the effects of probiotics on adult-type AD.
  
  
  OBJECTIVE
  To examine the effects of the probiotic Bifidobacterium animalis subsp lactis LKM512 on adult-type AD and the expression of metabolites that are known to be influenced by gut microbiota in fecal samples.
  
  
  METHODS
  Forty-four patients were randomly assigned to receive LKM512 or a placebo and underwent medical examinations. Fecal microbiota were analyzed with real-time polymerase chain reaction. Metabolomic analysis was conducted to search for antipruritic metabolites produced by intestinal bacteria using feces derived from 3 patients whose itch scores had improved using capillary electrophoresis with time-of-flight mass spectrometry. Antipruritic effects of kynurenic acid were observed using AD-induced NC/Nga mice.
  
  
  RESULTS
  LKM512 administration alleviated itch in AD patients compared with controls and improved the dermatology-specific quality-of-life scores when compared with the controls. Administration of LKM512 also increased the expression of the antipruritic and antinociceptive metabolite kynurenic acid (KYNA) in patients whose itch score had improved after LKM512 treatment. In mouse experiments, scratching behavior counts tended to be decreased by KYNA injection when compared with no treatment.
  
  
  CONCLUSIONS
  LKM512 administration may exert antipruritic effects by increasing KYNA production. LKM512 could therefore be a potentially effective therapeutic candidate for the reduction of pruritus.
  
  
  BACKGROUND
  umin.ac.jp/ctr Identifier: UMIN000005695.
authors.affiliation: Dairy Science and Technology Institute, Kyodo Milk Industry Co Ltd, Hinode, Tokyo, Japan. Electronic address: m-matumoto@meito.co.jp.
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: Chitofuna Dermatology Clinic, Setagaya, Tokyo, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Ebata
authors.affiliation: Hirooka Clinic, Shinjuku, Tokyo, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Hirooka
authors.affiliation: Hosoya Dermatology Clinic, Komae, Tokyo, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Hosoya
authors.affiliation: Inoue Clinic, Kawasaki, Kanagawa, Japan.
authors.forename: Natsuhiko
authors.initials: N
authors.lastname: Inoue
authors.affiliation: Itami Skin Clinic, Kashiwa, Chiba, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Itami
authors.affiliation: Tsuji Clinic, Shibuya, Tokyo, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tsuji
authors.affiliation: Yaginuma Dermatology Clinic, Kashiwa, Chiba, Japan.
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Yaginuma
authors.affiliation: Dairy Science and Technology Institute, Kyodo Milk Industry Co Ltd, Hinode, Tokyo, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Muramatsu
authors.affiliation: Dairy Science and Technology Institute, Kyodo Milk Industry Co Ltd, Hinode, Tokyo, Japan.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: Dairy Science and Technology Institute, Kyodo Milk Industry Co Ltd, Hinode, Tokyo, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Fujita
authors.affiliation: Yoga Allergy Clinic, Setagaya, Tokyo, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Nagakura
mesh_terms: D000328:Adult; D000700:Analgesics / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D000982:Antipruritics / Q000494:pharmacology / Q000627:therapeutic use*; D001644:Bifidobacterium / Q000276:immunology*; D003876:Dermatitis, Atopic / Q000188:drug therapy*; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D007165:Immunosuppression Therapy; D007422:Intestines / Q000382:microbiology; D007736:Kynurenic Acid / Q000494:pharmacology / Q000627:therapeutic use*; D019344:Lactic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D008297:Male; D055432:Metabolomics; D051379:Mice; D064307:Microbiota; D011073:Polyamines / Q000378:metabolism; D019936:Probiotics / Q000494:pharmacology / Q000627:therapeutic use*; D011537:Pruritus / Q000188:drug therapy / Q000382:microbiology; D011788:Quality of Life
chemical_list: D000700:Analgesics; D000982:Antipruritics; D011073:Polyamines; D019344:Lactic Acid; C031601:hydracrylic acid; D007736:Kynurenic Acid