Protective effect of probiotics in the treatment of infantile eczema

The Interaction between the Host Genome, Epigenome, and the Gut-Skin Axis Microbiome in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that occurs in genetically predisposed individuals. It involves complex interactions among the host immune system, environmental factors (such as skin barrier dysfunction), and microbial dysbiosis. Genome-wide association studies (GWAS) have identified AD risk alleles; however, the associated environmental factors remain largely unknown. Recent evidence suggests that altered microbiota composition (dysbiosis) in the skin and gut may contribute to the pathogenesis of AD. Examples of environmental factors that contribute to skin barrier dysfunction and microbial dysbiosis in AD include allergens, irritants, pollution, and microbial exposure. Studies have reported alterations in the gut microbiome structure in patients with AD compared to control subjects, characterized by increased abundance of Clostridium difficile and decreased abundance of short-chain fatty acid (SCFA)-producing bacteria such as Bifidobacterium. SCFAs play a critical role in maintaining host health, and reduced SCFA production may lead to intestinal inflammation in AD patients. The specific mechanisms through which dysbiotic bacteria and their metabolites interact with the host genome and epigenome to cause autoimmunity in AD are still unknown. By understanding the combination of environmental factors, such as gut microbiota, the genetic and epigenetic determinants that are associated with the development of autoantibodies may help unravel the pathophysiology of the disease. This review aims to elucidate the interactions between the immune system, susceptibility genes, epigenetic factors, and the gut microbiome in the development of AD.

Host-microbial interactions between PTGR2 and Bifidobacterium in the early life gut of atopic dermatitis children

BACKGROUND

Gut microbiota dysbiosis is linked to the development and responses of the immune system and can play an important role in the onset of allergic diseases including atopic dermatitis (AD). This study investigated the association between host genetics and the gut microbiota in AD.

METHODS

A global gene expression profiling of the gut epithelial colonocytes, genetic variations analysis, and the gut microbial composition analysis were performed.

RESULTS

This study identified the upregulation of PTGR2 (p = .028), a gene involved in prostaglandin catalysis and inflammatory responses, as a potential risk factor for AD. In subsequent fine mapping analysis using 17 single nucleotide polymorphisms (SNPs) of PTGR2 in 864 Korean subjects (420 AD patients and 444 unaffected controls), several SNPs and haplotypes showed significant associations with AD and its SCORing AD (SCORAD) values (p = .002). To investigate host-microbial interactions, further gut microbiota data and genotypes were obtained from an independent cohort of 176 subjects (91 AD patients and 85 controls). From correlation analysis, a significantly negative association between SNP and Bifidobacterium abundance was observed in AD patients (p = .005). In additional observations of PTGR2-associated downstream molecules, NRF2 (p = .004) and several antioxidant genes (GSTT1, GCLC, GPX1; p < .05) showed significantly reduced expression in AD patients.

CONCLUSIONS

Our current findings suggest that the interaction between PTGR2 dysregulated expression and a Bifidobacterium abundance affects a higher risk of AD and a more severe onset.

Microbiome Modulation as a Therapeutic Approach in Chronic Skin Diseases

There is a growing quantity of evidence on how skin and gut microbiome composition impacts the course of various dermatological diseases. The strategies involving the modulation of bacterial composition are increasingly in the focus of research attention. The aim of the present review was to analyze the literature available in PubMed (MEDLINE) and EMBASE databases on the topic of microbiome modulation in skin diseases. The effects and possible mechanisms of action of probiotics, prebiotics and synbiotics in dermatological conditions including atopic dermatitis (AD), psoriasis, chronic ulcers, seborrheic dermatitis, burns and acne were analyzed. Due to the very limited number of studies available regarding the topic of microbiome modulation in all skin diseases except for AD, the authors decided to also include case reports and original studies concerning oral administration and topical application of the pro-, pre- and synbiotics in the final analysis. The evaluated studies mostly reported significant health benefits to the patients or show promising results in animal or ex vivo studies. However, due to a limited amount of research and unambiguous results, the topic of microbiome modulation as a therapeutic approach in skin diseases still warrants further investigation.

Comparative effectiveness of probiotic strains for the treatment of pediatric atopic dermatitis: A systematic review and network meta-analysis

BACKGROUND

The current evidence on the use of probiotics in treating atopic dermatitis is inconclusive. This study determined the comparative effectiveness of the different types of probiotic strains in treating pediatric atopic dermatitis.

METHODOLOGY

Systematic and manual search for all randomized controlled trials available from inception until January 31, 2020, was done. Two independent authors conducted the search, screening, appraisal, and data abstraction. Network meta-analysis was conducted using STATA 14 software.

RESULTS

Twenty-two studies involving 28 different probiotic strains were included. The top three ranked probiotic strains in terms of efficacy are Mix1 (Bifidobacterium animalis subsp lactis CECT 8145, Bifidobacterium longum CECT 7347, and Lactobacillus casei CECT 9104); Lactobacillus casei DN-114001; and Mix6 (Bifidobacterium bifidum, Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus salivarius). Compared with placebo, Mix1 reduces atopic dermatitis symptoms with high certainty evidence (SMD -1.94, 95% CI -2.65 to -1.24; 47 participants). Mix6 compared with placebo probably reduces atopic dermatitis symptoms based on moderate certainty evidence (SMD -0.85, 95% CI -1.50 to -0.20; 40 participants). Lactobacillus casei DN-114001 compared with placebo may reduce atopic dermatitis symptoms based on low certainty evidence (SMD -1.35, 95% CI -2.04 to -0.65). In terms of safety, the highest ranked strain is Lactobacillus fermentum VRI-003, while the lowest ranked strain is Lactobacillus rhamnosus GG.

CONCLUSION

Certain probiotic preparations show benefit in reducing allergic symptoms in pediatric atopic dermatitis.

Prebiotics and probiotics in atopic dermatitis

Recent years have brought additional data on the benefits of prebiotics and probiotics treatment in patients with atopic dermatitis. This review includes all the articles published in PubMed, Scopus, Embase and Cochrane databases until 05.06.2018. The terms used for the search were 'prebiotic', 'probiotic', 'atopic dermatitis', 'Severity Scoring of Atopic Dermatitis', and 'SCORAD'. There was an increase of the intestinal permeability reported in patients with atopic dermatitis and a reduction of the cutaneous microbiome diversity. Probiotics modulate the general microbiome and immune status by improving the intestinal barrier; these effects can be responsible for reducing allergic phenomenon and atopic dermatitis severity. We have structured the results by age groups as infants, 1-18 years, adults, and also pregnancy and lactation. Literature does not offer yet answers on the issues such as the optimal dosing, duration needed to see beneficial effects, the optimal time to start the treatment; the personalized use of probiotics according to colonic dysbiosis may be associated with better results. However, most randomized controlled trials and meta-analyzes support the administration of probiotics for at least 8 weeks in order to obtain beneficial effects in improving severity scoring of atopic dermatitis.

Probiotics for treating eczema

BACKGROUND

Eczema is a common chronic skin condition. Probiotics have been proposed as an effective treatment for eczema; their use is increasing, as numerous clinical trials are under way. This is an update of a Cochrane Review first published in 2008, which suggested that probiotics may not be an effective treatment for eczema but identified areas in which evidence was lacking.

OBJECTIVES

To assess the effects of probiotics for treating patients of all ages with eczema.

SEARCH METHODS

We updated our searches of the following databases to January 2017: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library, the Global Resource of Eczema Trials (GREAT) database, MEDLINE, Embase, PsycINFO, the Allied and Complementary Medicine Database (AMED), and Latin American Caribbean Health Sciences Literature (LILACS). We searched five trials registers and checked the reference lists of included studies and relevant reviews for further references to relevant randomised controlled trials (RCTs). We also handsearched a number of conference proceedings. We updated the searches of the main databases in January 2018 and of trials registries in March 2018, but we have not yet incorporated these results into the review.

SELECTION CRITERIA

Randomised controlled trials of probiotics (live orally ingested micro-organisms) compared with no treatment, placebo, or other active intervention with no probiotics for the treatment of eczema diagnosed by a doctor.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane. We recorded adverse events from the included studies and from a separate adverse events search conducted for the first review. We formally assessed reporting bias by preparing funnel plots, and we performed trial sequential analysis for the first primary outcome - eczema symptoms at the end of active treatment.We used GRADE to assess the quality of the evidence for each outcome (in italic font).

MAIN RESULTS

We included 39 randomised controlled trials involving 2599 randomised participants. We included participants of either gender, aged from the first year of life through to 55 years (only six studies assessed adults), who had mild to severe eczema. Trials were undertaken in primary and secondary healthcare settings, mainly in Europe or Asia. Duration of treatment ranged from four weeks to six months, and duration of follow-up after end of treatment ranged from zero to 36 months. We selected no standard dose: researchers used a variety of doses and concentrations of probiotics. The probiotics used were bacteria of the Lactobacillus and Bifidobacteria species, which were taken alone or combined with other probiotics, and were given with or without prebiotics. Comparators were no treatment, placebo, and other treatments with no probiotics.For all results described in this abstract, the comparator was no probiotics. Active treatment ranged from six weeks to three months for all of the following results, apart from the investigator-rated eczema severity outcome, for which the upper limit of active treatment was 16 weeks. With regard to score, the higher the score, the more severe were the symptoms. All key results reported in this abstract were measured at the end of active treatment, except for adverse events, which were measured during the active treatment period.Probiotics probably make little or no difference in participant- or parent-rated symptoms of eczema (13 trials; 754 participants): symptom severity on a scale from 0 to 20 was 0.44 points lower after probiotic treatment (95% confidence interval (CI) -1.22 to 0.33; moderate-quality evidence). Trial sequential analysis shows that target sample sizes of 258 and 456, which are necessary to demonstrate a minimum mean difference of -2 and -1.5, respectively, with 90% power, have been exceeded, suggesting that further trials with similar probiotic strains for this outcome at the end of active treatment may be futile.We found no evidence suggesting that probiotics make a difference in QoL for patients with eczema (six studies; 552 participants; standardised mean difference (SMD) 0.03, 95% CI -0.36 to 0.42; low-quality evidence) when measured by the participant or the parent using validated disease-specific QoL instruments.Probiotics may slightly reduce investigator-rated eczema severity scores (24 trials; 1596 participants). On a scale of 0 to 103 for total Severity Scoring of Atopic Dermatitis (SCORAD), a score combining investigator-rated eczema severity score and participant scoring for eczema symptoms of itch and sleep loss was 3.91 points lower after probiotic treatment than after no probiotic treatment (95% CI -5.86 to -1.96; low-quality evidence). The minimum clinically important difference for SCORAD has been estimated to be 8.7 points.We noted significant to extreme levels of unexplainable heterogeneity between the results of individual studies. We judged most studies to be at unclear risk of bias; six studies had high attrition bias, and nine were at low risk of bias overall.We found no evidence to show that probiotics make a difference in the risk of adverse events during active treatment (risk ratio (RR) 1.54, 95% CI 0.90 to 2.63; seven trials; 402 participants; low-quality evidence). Studies in our review that reported adverse effects described gastrointestinal symptoms.

AUTHORS' CONCLUSIONS

Evidence suggests that, compared with no probiotic, currently available probiotic strains probably make little or no difference in improving patient-rated eczema symptoms. Probiotics may make little or no difference in QoL for people with eczema nor in investigator-rated eczema severity score (combined with participant scoring for eczema symptoms of itch and sleep loss); for the latter, the observed effect was small and of uncertain clinical significance. Therefore, use of probiotics for the treatment of eczema is currently not evidence-based. This update found no evidence of increased adverse effects with probiotic use during studies, but a separate adverse events search from the first review revealed that probiotic treatment carries a small risk of adverse events.Results show significant, unexplainable heterogeneity between individual trial results. Only a small number of studies measured some outcomes.Future studies should better measure QoL scores and adverse events, and should report on new probiotics. Researchers should also consider studying subgroups of patients (e.g. patients with atopy or food allergies, adults) and standardising doses/concentrations of probiotics given.

The impact of lifestyle factors on evolution of atopic dermatitis: An alternative approach

Atopic dermatitis (AD) is a multifactorial chronic inflammatory disease with an incompletely understood etiopathogenesis. With a significant impact on the quality of life of patients, AD has attracted the interest of many research studies aiming to investigate the complex cellular and molecular mechanisms and to identify new therapeutic pathways. Various studies have focused on psycho-immunology, emphasizing the involvement of stress, defined as a general response of the body to external or internal challenges to the AD pathology. Factors like lifestyle and leisure activities may change the behavior of immune cells in AD with a strong impact on the evolution of the disease. Moreover, the poor adherence of AD patient to standard treatment approach has led to the necessity to combine different therapies in the field of complementary and alternative medicine. Although there are still not enough data to conclude that adjuvant therapies are effective in a conventional sense, there are already promising results suggesting that alternative therapeutic strategies could be a main subject of further research.

Change in gut microbiota for eczema: Implications for novel therapeutic strategies

Eczema is one of the most common inflammatory diseases, often constituting a lifelong burden for afflicted individuals. The complex interaction of host genetic and multiple environmental factors contribute to its pathogenesis. A relationship between maladjustment of gut microbiota and eczema has been brought into the light of day in most previous studies. In eczema preclinical models, specific intestinal microbial species have been demonstrated to prohibit or dwindle immune responsiveness, indicating that these strains among commensal gut bacteria may exert either a morbific or phylactic function in eczema progression. As such, oral probiotics can serve as a medicinal approach for eczema therapy. Given that relative scientific work is still at the early stage, only limited data are available in the field. New sequencing techniques have been fortunately performed to gain access to an extended research on the relationship between gut bacterial flora and human diseases. In the current review, we identified the role of intestinal microbiota in the development of eczema and how specific bacterial strains adjust the immune responsiveness in the midst of disease progression. Probiotics as an applicable treatment for eczema were evaluated in other threads as well.

Selection, Characterization and Interaction Studies of a DNA Aptamer for the Detection of Bifidobacterium bifidum

A whole-bacterium-based SELEX (Systematic Evolution of Ligands by Exponential Enrichment) procedure was adopted in this study for the selection of an ssDNA aptamer that binds to Bifidobacterium bifidum. After 12 rounds of selection targeted against B. bifidum, 30 sequences were obtained and divided into seven families according to primary sequence homology and similarity of secondary structure. Four FAM (fluorescein amidite) labeled aptamer sequences from different families were selected for further characterization by flow cytometric analysis. The results reveal that the aptamer sequence CCFM641-5 demonstrated high-affinity and specificity for B. bifidum compared with the other sequences tested, and the estimated K_d value was 10.69 ± 0.89 nM. Additionally, sequence truncation experiments of the aptamer CCFM641-5 led to the conclusion that the 5'-primer and 3'-primer binding sites were essential for aptamer-target binding. In addition, the possible component of the target B. bifidum, bound by the aptamer CCFM641-5, was identified as a membrane protein by treatment with proteinase. Furthermore, to prove the potential application of the aptamer CCFM641-5, a colorimetric bioassay of the sandwich-type structure was used to detect B. bifidum. The assay had a linear range of 10⁴ to 10⁷ cfu/mL (R² = 0.9834). Therefore, the colorimetric bioassay appears to be a promising method for the detection of B. bifidum based on the aptamer CCFM641-5.

The Significance of the Enteric Microbiome on the Development of Childhood Disease: A Review of Prebiotic and Probiotic Therapies in Disorders of Childhood

Recent studies have highlighted the fact that the enteric microbiome, the trillions of microbes that inhabit the human digestive tract, has a significant effect on health and disease. Methods for manipulating the enteric microbiome, particularly through probiotics and microbial ecosystem transplantation, have undergone some study in clinical trials. We review some of the evidence for microbiome alteration in relation to childhood disease and discuss the clinical trials that have examined the manipulation of the microbiome in an effort to prevent or treat childhood disease with a primary focus on probiotics, prebiotics, and/or synbiotics (ie, probiotics + prebiotics). Studies show that alterations in the microbiome may be a consequence of events occurring during infancy and/or childhood such as prematurity, C-sections, and nosocomial infections. In addition, certain childhood diseases have been associated with microbiome alterations, namely necrotizing enterocolitis, infantile colic, asthma, atopic disease, gastrointestinal disease, diabetes, malnutrition, mood/anxiety disorders, and autism spectrum disorders. Treatment studies suggest that probiotics are potentially protective against the development of some of these diseases. Timing and duration of treatment, the optimal probiotic strain(s), and factors that may alter the composition and function of the microbiome are still in need of further research. Other treatments such as prebiotics, fecal microbial transplantation, and antibiotics have limited evidence. Future translational work, in vitro models, long-term and follow-up studies, and guidelines for the composition and viability of probiotic and microbial therapies need to be developed. Overall, there is promising evidence that manipulating the microbiome with probiotics early in life can help prevent or reduce the severity of some childhood diseases, but further research is needed to elucidate biological mechanisms and determine optimal treatments.