Randomized, placebo-controlled trial of Lactobacillus rhamnosus GG as treatment of atopic dermatitis in infancy

The role of probiotics in allergic diseases

Allergic disorders are very common in the pediatric age group. While the exact etiology is unclear, evidence is mounting to incriminate environmental factors and an aberrant gut microbiota with a shift of the Th1/Th2 balance towards a Th2 response. Probiotics have been shown to modulate the immune system back to a Th1 response. Several in vitro studies suggest a role for probiotics in treating allergic disorders. Human trials demonstrate a limited benefit for the use of probiotics in atopic dermatitis in a preventive as well as a therapeutic capacity. Data supporting their use in allergic rhinitis are less robust. Currently, there is no role for probiotic therapy in the treatment of bronchial asthma. Future studies will be critical in determining the exact role of probiotics in allergic disorders.

[Inside-Out. Probiotics and atopic dermatitis]

Orally administered probiotics have been employed for the prevention and therapy of atopic dermatitis in recent years, because both theoretical considerations and animal models suggested positive effects were likely. Current clinical studies make it clear that oral probiotics are not indicated for the therapy of mild, moderate or severe atopic dermatitis. A prevention study from Finland described a marked positive effect of lactobacilli on the rate of atopic dermatitis when the bacteria were given orally to the pregnant mother and the newborn. However, these positive results could not be reproduced by other investigators. Until these varying results are explained, no recommendation can be made for use of oral probiotics to prevent atopic dermatitis, as is stated in the current German S3 guideline on the prevention of allergies.

Probiotics for the treatment of eczema: a systematic review

BACKGROUND

Probiotics have been proposed as a treatment for eczema, but the results of intervention trials have been mixed.

OBJECTIVE

To evaluate the efficacy of probiotics for treating eczema by performing a systematic review of randomized-controlled trials (RCTs).

DESIGN

We searched the Cochrane Skin Group Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycINFO, AMED, LILACS, ISI Web of Science, the reference lists of articles, ongoing clinical trial registers and conference proceedings. RCTs of live orally ingested microorganisms for the treatment of eczema were eligible for inclusion.

RESULTS

Twelve trials (781 participants) were identified. Meta-analysis of data from five of these trials showed that there was no significant reduction in eczema symptoms with probiotic treatment compared with placebo (mean difference -0.90 points on a 20-point visual analogue scale; 95% confidence interval -2.84, 1.04). Meta-analysis of data from seven trials showed no significant difference in investigator rated eczema severity between probiotic and placebo treatments. Subgroup analysis by eczema severity or presence of atopy did not identify a specific population in which probiotic treatment was effective. There was significant heterogeneity between studies; however, the results of three studies that used the same probiotic strain were concordant. The adverse events search identified case reports of sepsis and bowel ischaemia caused by probiotics.

CONCLUSIONS

Currently, probiotics cannot be recommended for treating eczema. The heterogeneity between studies may be attributable to probiotic strain-specific effects, which means that novel probiotic strains may still have a role in eczema management.

Mechanisms of probiosis and prebiosis: considerations for enhanced functional foods

The technologies of metagenomics and metabolomics are broadening our knowledge of the roles the human gut microbiota play in health and disease. For many years now, probiotics and prebiotics have been included in foods for their health benefits; however, we have only recently begun to understand their modes of action. This review highlights recent advances in deciphering the mechanisms of probiosis and prebiosis, and describes how this knowledge could be transferred to select for enhancing functional foods targeting different populations. A special focus will be given to the addition of prebiotics and probiotics in functional foods for infants and seniors.

Probiotics for the prevention of respiratory tract infections: a systematic review

We evaluated the clinical evidence regarding probiotic use for the prevention of respiratory tract infections (RTIs). Randomised controlled trials (RCTs) studying the effects of probiotics for the prevention of upper or lower RTIs were systematically identified. Fourteen RCTs (twelve involving healthy subjects and two involving patients with RTIs) were included. Various Lactobacillus strains were used in seven RCTs, combinations of Lactobacillus and Bifidobacterium strains were used in five RCTs, and a Bifidobacterium strain and a non-pathogenic Enterococcus faecalis strain were used in one RCT, respectively. In ten RCTs no difference was found regarding the incidence of RTIs in the probiotic arm compared with the control arm, whereas the remaining four RCTs favoured the use of probiotics. Reduction in the severity of symptoms related to RTIs was noted in five of six RCTs that provided relevant data. In three of nine RCTs that provided relevant data, the clinical course of RTIs was shorter in the probiotic arm, whereas no difference was found in the remaining six RCTs. In conclusion, probiotics may have a beneficial effect on the severity and duration of symptoms of RTIs but do not appear to reduce the incidence of RTIs.

Conditioned polarized Caco-2 cell monolayers allow to discriminate for the ability of gut-derived microorganisms to modulate permeability and antigen-induced basophil degranulation

BACKGROUND

Food allergy is a common allergic disorder--especially in early childhood. The avoidance of the allergenic food is the only available method to prevent further reactions in sensitized patients. A better understanding of the immunologic mechanisms involved in this reaction would help to develop therapeutic approaches applicable to the prevention of food allergy.

OBJECTIVE

To establish a multi-cell in vitro model of sensitized intestinal epithelium that mimics the intestinal epithelial barrier to study the capacity of probiotic microorganisms to modulate permeability, translocation and immunoreactivity of ovalbumin (OVA) used as a model antigen.

METHODS

Polarized Caco-2 cell monolayers were conditioned by basolateral basophils and used to examine apical to basolateral transport of OVA by ELISA. Activation of basophils with translocated OVA was measured by beta-hexosaminidase release assay. This experimental setting was used to assess how microorganisms added apically affected these parameters. Basolateral secretion of cytokine/chemokines by polarized Caco-2 cell monolayers was analysed by ELISA.

RESULTS

Basophils loaded with OVA-specific IgE responded to OVA in a dose-dependent manner. OVA transported across polarized Caco-2 cell monolayers was found to trigger basolateral basophil activation. Microorganisms including lactobacilli and Escherichia coli increased transepithelial electrical resistance while promoting OVA passage capable to trigger basophil activation. Non-inflammatory levels of IL-8 and thymic stromal lymphopoietin were produced basolaterally by Caco-2 cells exposed to microorganisms.

CONCLUSION

The complex model designed in here is adequate to learn about the consequence of the interaction between microorganisms and epithelial cells vis-a-vis the barrier function and antigen translocation, two parameters essential to mucosal homeostasis. It can further serve as a direct tool to search for microorganisms with anti-allergic and anti-inflammatory properties.

Efficacy of probiotics in the treatment of pediatric atopic dermatitis: a meta-analysis of randomized controlled trials

BACKGROUND

Several articles describing the efficacy of probiotics in atopic dermatitis (AD) have been published. However, not all studies support a similar outcome.

OBJECTIVE

To determine whether probiotics are efficacious in treating AD and to explore whether type of probiotic used, duration of therapy, patient age, severity of disease, and IgE sensitization are factors in determining efficacy.

METHODS

For this meta-analysis of randomized controlled trials describing the efficacy of probiotics in AD, a comprehensive search was performed of databases through January 2008. Three reviewers independently evaluated the studies for methodological qualities. All the data were analyzed, and forest plots were evaluated for the overall efficacy of probiotics in AD and the therapeutic benefit to subgroups of selected patient populations.

RESULTS

Eleven studies were identified, and data from 10 studies (n = 678) were available to analyze. There was an overall statistically significant difference favoring probiotics compared with placebo in reducing the Scoring of Atopic Dermatitis Severity Index score (mean change from baseline, -3.01; 95% confidence interval, -5.36 to -0.66; P = .01). Children with moderately severe disease were more likely to benefit. Duration of probiotic administration, age, and type of probiotic used did not affect outcome.

CONCLUSION

Data from this meta-analysis suggest a modestrole for probiotics in pediatric AD. The effect is seen in moderately severe rather than mild disease.

Early atopic disease and early childhood immunization--is there a link?

BACKGROUND

There are frequent concerns about early immunizations among the parents of children at heightened risk for atopy. The study assessed the effect of vaccine immunization before the first birthday on eczema severity and allergic sensitization in the second year of life.

METHODS

A total of 2184 infants, aged 1-2 years, with established atopic dermatitis and a family history of allergy, from 97 study centres in 10 European countries, South Africa and Australia were included. Exposure to vaccines (diphtheria, tetanus, pertussis, polio, Haemophilus influenzae Type B, hepatitis B, mumps, measles, rubella, varicella, BCG, meningococci and pneumococci) and immunization dates were recorded from immunization cards. Immunoglobulin E (IgE) was determined by RAST and eczema severity was assessed by scoring atopic dermatitis (SCORAD).

RESULTS

Immunization against any target was not associated with an increased risk of allergic sensitization to food or inhalant allergens. Varicella immunization (only 0.7% immunized) was inversely associated with total IgE > 30 kU/l (OR 0.27; 95% CI 0.08-0.87) and eczema severity (OR 0.34; 95% CI 0.12-0.93). Pertussis immunization (only 1.7% nonimmunized) was inversely associated with eczema severity (OR 0.30; 95% CI 0.10-0.89). Cumulative received vaccine doses were inversely associated with eczema severity (P = 0.0107). The immunization coverage of infants before and after the onset of atopic dermatitis was similar.

CONCLUSION

In children at heightened risk for atopy, common childhood immunization in the first year is not associated with an increased risk of more severe eczema or allergic sensitization. Parents of atopic children should be encouraged to fully immunize their children.

The human microbiome and probiotics: implications for pediatrics

The “human super-organism” refers to the human body and the massive numbers of microbes which dwell within us and on the skin surface. Despite the large numbers of microbes co-existing within the human body, humans including infants and children achieve a physiologic state of equilibrium known as health in the context of this microbial world. These key concepts suggest that many individual members of the human microbiome, including bacterial and fungal species, confer different benefits on the human host. Probiotics, or beneficial microbes, may modulate immune responses, provide key nutrients, or suppress the proliferation and virulence of infectious agents. The human microbiome is in fact dynamic and often in flux, which may be indicative of the continuous interplay among commensal microbes, pathogens, and the human host. In this article we review the state-of-the-art regarding probiotics applications to prevent or treat diseases of the pediatric gastrointestinal and genitourinary systems. Additionally, probiotics may regulate local and systemic immunity, thereby reducing allergic disease severity and susceptibilities of infants and children to allergies and atopic diseases. In summary, beneficial microbes offer promising alternatives for new strategies in therapeutic microbiology with implications for different subspecialties within pediatrics. Instead of simply trying to counteract microbes with vaccines and antibiotics, a new field of medical microbiology is emerging that strives to translate human microbiome research into new probiotics strategies for promotion of health and prevention of disease in children.

Probiotics for treating eczema

BACKGROUND

Probiotics have been proposed as an effective treatment for eczema, and recently a number of clinical trials have been undertaken.

OBJECTIVES

To assess the effects of probiotics for the treatment of eczema

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register (to April 2008), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2,2008) MEDLINE (from 2003 to April 2008), EMBASE (from 2005 to April 2008), PsycINFO, AMED and LILACS (from inception to April 2008) and ISI Web of Science (to December 2006) and reference lists of articles. We also searched registries of ongoing clinical trials, conference proceedings and searched for adverse events.

SELECTION CRITERIA

Randomised controlled trials of live orally ingested microorganisms for the treatment of eczema.

DATA COLLECTION AND ANALYSIS

Two authors independently applied eligibility criteria, assessed the quality of trials and extracted data. We contacted study authors for more information where necessary. We recorded adverse events from the included studies, and from the separate adverse events search.

MAIN RESULTS

Twelve randomised controlled trials involving 781 participants met the inclusion criteria. All trial participants were children. There was no significant difference in participant or parent-rated symptom scores in favour of probiotic treatment (5 trials, 313 participants). Symptom severity on a scale from 0 to 20 was 0.90 points lower after probiotic treatment than after placebo (95%CI -1.04, 2.84; p = 0.36).There was also no significant difference in participant or parent-rated overall eczema severity in favour of probiotic treatment (3 trials, 150 participants). There was no significant difference in investigator rated eczema severity between probiotic and placebo treatments (7 trials, 588 participants). On a scale from 0 to 102 investigator rated eczema severity was 2.46 points lower after probiotic treatment than after placebo treatment (95%CI -2.53, 7.45 p = 0.33). Significant heterogeneity was noted between the results of individual studies, which may be explained by the use of different probiotic strains. Subgroup analysis by age of participant, severity of eczema, presence of atopy or presence of food allergy did not identify a population with different treatment outcomes to the population as a whole. The adverse events search identified some case reports of infections and bowel ischaemia caused by probiotics.

AUTHORS' CONCLUSIONS

The evidence suggests that probiotics are not an effective treatment for eczema, and probiotic treatment carries a small risk of adverse events.

Effects of nonpathogenic gram-negative bacterium Vitreoscilla filiformis lysate on atopic dermatitis: a prospective, randomized, double-blind, placebo-controlled clinical study

BACKGROUND

Atopic dermatitis (AD) is associated with elevated IgE levels and Th2 responses. The oral administration of nonpathogenic bacteria such as probiotics may improve the course of atopic diseases. It is believed that nonpathogenic bacteria prevent the development of allergic diseases by modulating intestinal immune responses. However, the effects of oral probiotics on AD could not be reproduced in all studies and the direct immunomodulation of the skin-associated immune response by nonpathogenic bacteria has not yet been investigated.

OBJECTIVES

We performed a prospective, double-blind, placebo-controlled clinical study with a cream containing a 5% lysate of the nonpathogenic bacteria Vitreoscilla filiformis.

PATIENTS AND METHODS

Seventy-five volunteers with AD (6-70 years of age) were randomized to receive either V. filiformis cream 5% or vehicle cream daily for 30 days. Efficacy was evaluated by the SCORe of Atopic Dermatitis (SCORAD), transepidermal water loss (TEWL), assessment of microflora, and the patient's assessment of itch and loss of sleep.

RESULTS

Compared with placebo, V. filiformis lysate significantly decreased SCORAD levels (P=0.0044) and pruritus (P=0.0171). Active cream significantly decreased loss of sleep from day 0 to day 29 (P=0.0074). Qualitative and quantitative assessment of cutaneous microbial colonization revealed that V. filiformis lysate reduced Staphylococcus aureus colonization of the skin. The skin barrier as determined by TEWL also improved significantly with the cream alone.

CONCLUSIONS

V. filiformis lysate significantly improved AD. This may be in part due to reduction of S. aureus, but seems to relate in most parts to a direct immunomodulatory effect on skin-associated immune responses.

The role of food allergy in atopic dermatitis

Atopic dermatitis (AD) is a chronic, pruritic, inflammatory skin disease affecting more than 10% of all children. Sensitization to foods triggers isolated skin symptoms in about 30% of children. These symptoms include immediate reactions within minutes after ingesting food without exacerbation of AD and early and late exacerbations of AD. It is important to identify clinically relevant sensitizations to foods using skin prick tests, a specific IgE blood test (ImmunoCAP; Phadia, Portage, MI, USA), and double-blind, placebo-controlled food challenges to initiate appropriate dietary interventions and avoid unnecessary dietary restrictions. Children with AD triggered by food allergens demonstrate a distinct immune response upon stimulation of their peripheral blood mononuclear cells with food allergen. A defective skin barrier and increased intestinal permeability appear to facilitate allergen sensitization. Appropriate skin care to maintain skin barrier function and dietary avoidance of highly allergenic foods during infancy may help to prevent allergen sensitization, thereby reducing the severity of AD and food allergies.