Antipruritic effects of the probiotic strain LKM512 in adults with atopic dermatitis.

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. CONCLUSION: LKM512 administration may exert antipruritic effects by increasing KYNA production. LKM512 could therefore be a potentially effective therapeutic candidate for the reduction of pruritus. TRIAL REGISTRATION: umin.ac.jp/ctr Identifier: UMIN000005695.

Development and validation of the psychosomatic scale for atopic dermatitis in adults.

Psychosocial factors play an important role in the course of adult atopic dermatitis (AD). Nevertheless, AD patients are rarely treated for their psychosomatic concerns. The purpose of the present study was to develop and validate a brief self-rating scale for adult AD in order to aid dermatologists in evaluating psychosocial factors during the course of AD. A preliminary scale assessing stress-induced exacerbation, the secondary psychosocial burden, and attitude toward treatment was developed and administered to 187 AD patients (82 male, 105 female, aged 28.4 +/- 7.8, 13-61). Severity of skin lesions and improvement with standard dermatological treatment were assessed by both the dermatologist and the participant. Measures of anxiety and depression were also determined. In addition, psychosomatic evaluations were made according to the Psychosomatic Diagnostic Criteria for AD. Factor analysis resulted in the development of a 12-item scale (The Psychosomatic Scale for Atopic Dermatitis; PSS-AD) consisting of three factors: (i) exacerbation triggered by stress; (ii) disturbances due to AD; and (iii) ineffective control. Internal consistency indicated by Cronbach's alpha coefficient was 0.86 for the entire measure, 0.82 for (i), 0.81 for (ii), and 0.77 for (iii), verifying the acceptable reliability of PSS-AD. Patients with psychosomatic problems had higher PSS-AD scores than those without. PSS-AD scores were positively associated with the severity of the skin lesions, anxiety and depression. The scores were negatively associated with improvement during dermatological treatments. In conclusion, PSS-AD is a simple and reliable measure of the psychosomatic pathology of adult AD patients. It may be useful in dermatological practice for screening patients who would benefit from psychological or psychiatric interventions.