Effect of aMycobacterium vaccaederivative on paediatric atopic dermatitis: a randomized, controlled trial

Next-Gen biotherapeutics: A systematic review and network meta-analysis on postbiotics as treatment for pediatric atopic dermatitis

BACKGROUND

Due to the recency of the postbiotic field, no head-to-head postbiotic studies have investigated its biotherapeutic potential for atopic dermatitis (AD). No network meta-analysis (NMA) has been conducted to synthesize relevant studies comparing postbiotic interventions for AD.

OBJECTIVE

To assess the comparative efficacy and safety of postbiotic strains in the treatment of pediatric AD.

METHODOLOGY

This was an NMA of randomized controlled studies that evaluated postbiotics in treating pediatric AD. Systematic search of databases and registers from inception to November 30, 2022. Three authors independently performed the search, screening, and appraisal using the Cochrane risk-of-bias tool version 2 and data extraction. Data analysis was performed using STATA14 software.

RESULTS

Nine studies evaluated eight postbiotic preparations. Lactobacillus rhamnosus IDCC 3201 (LR) ranked highest in the efficacy outcome. Compared to placebo, LR may be effective in reducing symptoms of atopic dermatitis in the main analysis (SMD -0.53, 95%CI -1.02 to -0.04) and sensitivity analysis involving studies that used SCORAD (MD -5.52, 95% CI -10.46 to -0.58), based on low-certainty evidence. Based on moderate-certainty evidence, LR probably did not increase the risk of adverse events (RR 0.97, 95% CI 0.79, 1.21). Although Lactobacillus paracasei GM080 (LP2) ranked highest in the safety outcome, it may not reduce AD symptoms compared to placebo (SMD -0.03, 95% CI -0.37, 0.32) based on low-certainty evidence.

CONCLUSION

LR showed significant benefits in children with AD based on low-certainty evidence. Further investigation of LR is recommended.

Recent advances in the concept of paraprobiotics: Nutraceutical/functional properties for promoting children health

Probiotics consumption has been associated with various health promoting benefits, including disease prevention and even treatment by modulating gut microbiota. Contrary to this, probiotics may also overstimulate the immune system, trigger systemic infections, harmful metabolic activities, and promote gene transfer. In children, the fragile immune system and impaired intestinal barrier may boost the occurrence of adverse effects following probiotics' consumption. To overcome these health challenges, the key focus has been shifted toward non-viable probiotics, also called paraprobiotics. Cell wall polysaccharides, peptidoglycans, surface proteins and teichoic acid present on cell's surface are involved in the interaction of paraprobiotics with the host, ultimately providing health benefits. Among other benefits, paraprobiotics possess the ability to regulate innate and adaptive immunity, exert anti-adhesion, anti-biofilm, anti-hypertensive, anti-inflammatory, antioxidant, anti-proliferative, and antagonistic effects against pathogens, while also enhance clinical impact and general safety when administered in children in comparison to probiotics. Clinical evidence have underlined the paraprobiotics impact in children and young infants against atopic dermatitis, respiratory and gastrointestinal infections, in addition to be useful for immunocompromised individuals. Therefore, this review focuses on probiotics-related issues in children's health and also discusses the Lactobacillus and Bifidobacterium spp. qualities for qualifying as paraprobiotics and their role in promoting the children's health.

Postbiotics and paraprobiotics: A review of current evidence and emerging trends

In recent years, new probiotic-related concepts such as postbiotics and paraprobiotics have been coined to indicate that non-viable microorganisms or bacterial-free extracts may provide benefits to the host by offering additional bioactivities to probiotics, including but not limited to anti-inflammatory, immunomodulatory, anti-proliferative and antioxidant activities. Despite in vitro and in vivo studies that support the promising use of postbiotics and paraprobiotics as health promoters, the mechanism of action and the signaling pathway involved have not yet been fully elucidated. Therefore, the aim of this chapter is to provide an overview of novel probiotic-related concepts and the scientific evidence that supports their bioactivities as well as the possible mechanisms underlying their health-promoting effects. Additionally, current trends in food, feed, and pharmaceutical applications are discussed.

Short-term direct contact with soil and plant materials leads to an immediate increase in diversity of skin microbiota

Immune‐mediated diseases have increased during the last decades in urban environments. The hygiene hypothesis suggests that increased hygiene level and reduced contacts with natural biodiversity are related to the increase in immune‐mediated diseases. We tested whether short‐time contact with microbiologically diverse nature‐based materials immediately change bacterial diversity on human skin. We tested direct skin contact, as two volunteers rubbed their hands with sixteen soil and plant based materials, and an exposure via fabric packets filled with moss material. Skin swabs were taken before and after both exposures. Next‐generation sequencing showed that exposures increased, at least temporarily, the total diversity of skin microbiota and the diversity of Acidobacteria, Actinobacteria, Bacteroidetes, Proteobacteria and Alpha‐, Beta‐ and Gammaproteobacteria suggesting that contact with nature‐based materials modify skin microbiome and increase skin microbial diversity. Until now, approaches to cure or prevent immune system disorders using microbe‐based treatments have been limited to use of a few microbial species. We propose that nature‐based materials with high natural diversity, such as the materials tested here, might be more effective in modifying human skin microbiome, and eventually, in reducing immune system disorders. Future studies should investigate how long‐term changes in skin microbiota are achieved and if the exposure induces beneficial changes in the immune system markers.

Is there a role for modified probiotics as beneficial microbes: a systematic review of the literature

Our objective was to conduct a systematic review and meta-analysis for the use of modified (heat-killed or sonicated) probiotics for the efficacy and safety to prevent and treat various diseases. Recent clinical research has focused on living strains of probiotics, but use in high-risk patients and potential adverse reactions including bacteremia has focused interest on alternatives to the use of live probiotics. We searched MEDLINE/PubMed, Embase, Cochrane Central Register of Controlled Trials, CINAHL, Alt Health Watch, Web of Science, Scopus, PubMed, from inception to February 14, 2017 for randomised controlled trials involving modified probiotic strains. The primary outcome was efficacy to prevent or treat disease and the secondary outcome was incidence of adverse events. A total of 40 trials were included (n=3,913): 14 trials (15 arms with modified probiotics and 20 control arms) for the prevention of diseases and 26 trials (29 arms with modified probiotics and 32 control arms) for treatment of various diseases. Modified microbes were compared to either placebo (44%), or the same living probiotic strain (39%) or to only standard therapies (17%). Modified microbes were not significantly more or less effective than the living probiotic in 86% of the preventive trials and 69% of the treatment trials. Modified probiotic strains were significantly more effective in 15% of the treatment trials. Incidence rates of adverse events were similar for modified and living probiotics and other control groups, but many trials did not collect adequate safety data. Although several types of modified probiotics showed significant efficacy over living strains of probiotics, firm conclusions could not be reached due to the limited number of trials using the same type of modified microbe (strain, daily dose and duration) for a specific disease indication. Further research may illuminate other strains of modified probiotics that may have potential as clinical biotherapeutics.

Adjuvant treatment with the bacterial lysate (OM-85) improves management of atopic dermatitis: A randomized study

Background

Environmental factors play a major role on atopic dermatitis (AD) which shows a constant rise in prevalence in western countries over the last decades. The Hygiene Hypothesis suggesting an inverse relationship between incidence of infections and the increase in atopic diseases in these countries, is one of the working hypothesis proposed to explain this trend.

Objective

This study tested the efficacy and safety of oral administration of the bacterial lysate OM-85 (Broncho-Vaxom^®, Broncho-Munal^®, Ommunal^®, Paxoral^®, Vaxoral^®), in the treatment of established AD in children.

Methods

Children aged 6 months to 7 years, with confirmed AD diagnosis, were randomized in a double-blind, placebo-controlled trial to receive, in addition to conventional treatment with emollients and topical corticosteroids, 3.5mg of the bacterial extract OM-85 or placebo daily for 9 months. The primary end-point was the difference between groups in the occurrence of new flares (NF) during the study period, evaluated by Hazard Ratio (HR) derived from conditional Cox proportional hazard regression models accounting for repeated events.

Results

Among the 179 randomized children, 170 were analysed, 88 in the OM-85 and 82 in the placebo group. As expected most children in both treatment groups experienced at least 1 NF during the study period (75 (85%) patients in the OM-85 group and 72 (88%) in the placebo group). Patients treated with OM-85 as adjuvant therapy had significantly fewer and delayed NFs (HR of repeated flares = 0.80; 95% confidence interval (CI): 0.67–0.96), also when potential confounding factors, as family history of atopy and corticosteroids use, were taken into account (HR = 0.82; 95% CI: 0.69–0.98). No major side effect was reported, with comparable and good tolerability for OM-85 and placebo.

Conclusions

Results show an adjuvant therapeutic effect of a well standardized bacterial lysate OM-85 on established AD.

Scoping systematic review of treatments for eczema

Background

Eczema is a very common chronic inflammatory skin condition.

Objectives

To update the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) systematic review of treatments for atopic eczema, published in 2000, and to inform health-care professionals, commissioners and patients about key treatment developments and research gaps.

Data sources

Electronic databases including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Skin Group Specialised Register, Latin American and Caribbean Health Sciences Literature (LILACS), Allied and Complementary Medicine Database (AMED) and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched from the end of 2000 to 31 August 2013. Retrieved articles were used to identify further randomised controlled trials (RCTs).

Review methods

Studies were filtered according to inclusion criteria and agreed by consensus in cases of uncertainty. Abstracts were excluded and non-English-language papers were screened by international colleagues and data were extracted. Only RCTs of treatments for eczema were included, as other forms of evidence are associated with higher risks of bias. Inclusion criteria for studies included availability of data relevant to the therapeutic management of eczema; mention of randomisation; comparison of two or more treatments; and prospective data collection. Participants of all ages were included. Eczema diagnosis was determined by a clinician or according to published diagnostic criteria. The risk of bias was assessed using the Cochrane Collaboration risk-of-bias tool. We used a standardised approach to summarising the data and the assessment of risk of bias and we made a clear distinction between what the studies found and our own interpretation of study findings.

Results

Of 7198 references screened, 287 new trials were identified spanning 92 treatments. Trial reporting was generally poor (randomisation method: 2% high, 36% low, 62% unclear risk of bias; allocation concealment: 3% high, 15% low, 82% unclear risk of bias; blinding of the intervention: 15% high, 28% low, 57% unclear risk of bias). Only 22 (8%) trials were considered to be at low risk of bias for all three criteria. There was reasonable evidence of benefit for the topical medications tacrolimus, pimecrolimus and various corticosteroids (with tacrolimus superior to pimecrolimus and corticosteroids) for both treatment and flare prevention; oral ciclosporin; oral azathioprine; narrow band ultraviolet B (UVB) light; Atopiclair™ and education. There was reasonable evidence to suggest no clinically useful benefit for twice-daily compared with once-daily topical corticosteroids; corticosteroids containing antibiotics for non-infected eczema; probiotics; evening primrose and borage oil; ion-exchange water softeners; protease inhibitor SRD441 (Serentis Ltd); furfuryl palmitate in emollient; cipamfylline cream; andMycobacterium vaccaevaccine. Additional research evidence is needed for emollients, bath additives, antibacterials, specialist clothing and complementary and alternative therapies. There was no RCT evidence for topical corticosteroid dilution, impregnated bandages, soap avoidance, bathing frequency or allergy testing.

Limitations

The large scope of the review coupled with the heterogeneity of outcomes precluded formal meta-analyses. Our conclusions are still limited by a profusion of small, poorly reported studies.

Conclusions

Although the evidence base of RCTs has increased considerably since the last NIHR HTA systematic review, the field is still severely hampered by poor design and reporting problems including failure to register trials and declare primary outcomes, small sample size, short follow-up duration and poor reporting of risk of bias. Key areas for further research identified by the review include the optimum use of emollients, bathing frequency, wash products, allergy testing and antiseptic treatments. Perhaps the greatest benefit identified is the use of twice weekly anti-inflammatory treatment to maintain disease remission. More studies need to be conducted in a primary care setting where most people with eczema are seen in the UK. Future studies need to use the same core set of outcomes that capture patient symptoms, clinical signs, quality of life and the chronic nature of the disease.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Quality of life impact of childhood skin conditions measured using the Children's Dermatology Life Quality Index (CDLQI): a meta-analysis

BACKGROUND

The Children's Dermatology Life Quality Index (CDLQI) is the most widely used instrument for measuring the impact of skin disease on quality of life (QoL) in children.

OBJECTIVES

To provide a meta-analysis of all published QoL scores for a range of childhood skin conditions.

METHODS

Studies using the CDLQI questionnaire to measure QoL in skin conditions were identified by searching Medline and Embase from January 1995 (CDLQI creation) to December 2014. Studies were grouped according to condition and baseline scores were combined using meta-analysis.

RESULTS

Sixty-seven studies using the CDLQI met the inclusion criteria. The overall estimated CDLQI scores for conditions reported more than once were [point estimate (95% confidence interval, CI), number of studies (n), score range]: atopic eczema [8·5 (7·1-9·8), n = 38, 0-29], acne [5·3 (1·9-8·5), n = 5, 0-30], alopecia [3·1 (0-7·7), n = 2, 0-6], molluscum contagiosum [3·5 (0·6-6·7), n = 5, 0-27], psoriasis [8·0 (3·9-12·1), n = 6, 0-29], scabies [9·2 (0·0-20·3), n = 2, 1-26], urticaria [7·1 (0-15·4), n = 2, 0-22], vitiligo [6·5 (0·7-12·2), n = 2, 0-20] and warts [2·9 (0-5·8), n = 4, 0-16]. Overall, the mean effect on QoL [weighted average CDLQI score 4·6 (95% CI 3·9-5·4)] for children with these conditions was small. However, many children were found to experience a very large impact on QoL (34% of children with atopic eczema, 10% with molluscum contagiosum and 1-5% with acne) in studies where the distributions of scores were provided.

CONCLUSIONS

Most skin conditions in children have a 'small' mean effect on QoL. However, the range is large and a significant proportion of children with many common skin conditions will experience a very large effect on quality of life.

Clinical experience and psychometric properties of the Children's Dermatology Life Quality Index (CDLQI), 1995-2012

The Children's Dermatology Life Quality Index (CDLQI) is a widely used questionnaire to measure the quality of life of children aged from 4 to 16 years. The purpose of this review is to summarize all published data regarding the clinical experience of the CDLQI and its psychometric properties as a single reference source for potential users. A literature search was carried out to identify all articles describing the use of the CDLQI from 1995 to November 2012. One hundred and six articles were identified, with four excluded. The CDLQI has been used in 28 countries in 102 clinical studies and is available in 44 languages, including six cultural adaptations; a cartoon version is available in 10 languages. It has been used in 14 skin conditions and used in the assessment of 11 topical drugs, nine systemic drugs, 13 therapeutic interventions and two epidemiological and other studies. There is evidence of high internal consistency, test-retest reliability, responsiveness to change, and significant correlation with other subjective and objective measures. Rasch analysis has not been carried out and more information is needed concerning minimal clinically important difference; these are areas requiring further study.

Prerequisites for the pharmaceutical industry to develop and commercialise helminths and helminth-derived product therapy

During the past 10 years, immunologists, epidemiologists and parasitologists have made many new exciting discoveries in the field of helminth-mediated immune regulation. In addition, many animal experiments have shown that certain helminths or products derived from helminths can protect mice from developing allergic or autoimmune disease. Some clinical trials utilising Trichuris suis or Necator americanus for the treatment of allergic disorders and inflammatory bowel disease have been conducted. The outcomes of these trials suggest that they may be used to treat these disorders. However, to date no helminth therapy is routinely being applied to patients and no helminth-derived product therapy has been developed. In order to bring new drugs to the market and shoulder the enormous costs involved in developing such therapies, pharmaceutical companies need to be involved. However, currently the resources from the pharmaceutical industry devoted to this concept are relatively small and there are good reasons why the industry may have been reluctant to invest in developing these types of therapies. In this review article, the hurdles that must be overcome before the pharmaceutical industry might invest in these novel therapies are outlined.

Components of Streptococcus pneumoniae suppress allergic airways disease and NKT cells by inducing regulatory T cells

Asthma is an allergic airways disease (AAD) caused by dysregulated immune responses and characterized by eosinophilic inflammation, mucus hypersecretion, and airway hyperresponsiveness (AHR). NKT cells have been shown to contribute to AHR in some mouse models. Conversely, regulatory T cells (Tregs) control aberrant immune responses and maintain homeostasis. Recent evidence suggests that Streptococcus pneumoniae induces Tregs that have potential to be harnessed therapeutically for asthma. In this study, mouse models of AAD were used to identify the S. pneumoniae components that have suppressive properties, and the mechanisms underlying suppression were investigated. We tested the suppressive capacity of type-3-polysaccharide (T3P), isolated cell walls, pneumolysoid (Ply) and CpG. When coadministered, T3P + Ply suppressed the development of: eosinophilic inflammation, Th2 cytokine release, mucus hypersecretion, and AHR. Importantly, T3P + Ply also attenuated features of AAD when administered during established disease. We show that NKT cells contributed to the development of AAD and also were suppressed by T3P + Ply treatment. Furthermore, adoptive transfer of NKT cells induced AHR, which also could be reversed by T3P + Ply. T3P + Ply-induced Tregs were essential for the suppression of NKT cells and AAD, which was demonstrated by Treg depletion. Collectively, our results show that the S. pneumoniae components T3P + Ply suppress AAD through the induction of Tregs that blocked the activity of NKT cells. These data suggest that S. pneumoniae components may have potential as a therapeutic strategy for the suppression of allergic asthma through the induction of Tregs and suppression of NKT cells.

DC priming by M. vaccae inhibits Th2 responses in contrast to specific TLR2 priming and is associated with selective activation of the CREB pathway

The environmental mycobacterium, M. vaccae has been used in mouse models to support the contemporary hygiene hypothesis that non-pathogenic microorganisms reduce allergy associated T helper (Th)2 responses and inflammatory diseases by augmenting regulatory T cells. However, data for human models and possible mechanisms are limited. We tested the effect of innate immune interactions between human DC and M. vaccae on DC-dependent T cell responses. M. vaccae activation of DC via Toll like receptor (TLR)2 was compared to a specific TLR2 ligand (Pam(3)CSK4) and alternative stimulation with a TLR4 ligand (LPS). M. vaccae induced DC dependent inhibition of Th2 responses, in contrast to Pam(3)CSK4, which had the opposite effect and LPS, which had no polarizing effect. DC maturation, gene expression and cytokine production, in response to each stimulus did not correlate with the specific functional effects. Comparable DC transcriptional responses to M. vaccae and Pam(3)CSK4 suggested that TLR2 mediated transcriptional regulation was not sufficient for inhibition of Th2 responses. Transcription factor enrichment analysis and assessment of signaling events, implicated a role for selective early activation of the CREB pathway by M. vaccae. Further study of the CREB pathway may provide novel insight into the molecular mechanisms of DC-dependent T cell polarization.

The effects of Mycobacteria vaccae derivative on allergen-specific responses in children with atopic dermatitis

The capacity of microbial products to inhibit allergic inflammation make them logical candidates for novel therapies in allergic diseases such as atopic dermatitis. To assess the effects of intradermal Mycobacterium vaccae derivative on allergen-specific immune responses in children with moderate to severe atopic dermatitis. Peripheral blood mononuclear cells were isolated from children aged 5-16 years who received intradermal injections of M. vaccae derivative AVAC(TM) (n = 26) or placebo (n = 34) three times at 2-weekly intervals, weeks 0, 2 and 4. Cytokine [interleukin (IL)-13, interferon (IFN)-γ and IL-10] responses to allergen [house dust mite (HDM)], mitogen [phytohaemagglutinin (PHA)], Staphylococcal enterotoxin B (SEB) and Toll-like receptor (TLR) ligands were assessed. At week 8 (1 month after all injections given) children in the AVAC group showed a significant increase in IL-10 (P = 0·009), T helper type 1 (Th1) IFN-γ (P = 0·017) and Th2 IL-13 (P = 0·004) responses to HDM compared with baseline (week 0). There were no significant changes in any cytokine production in the placebo. HDM-specific IL-10 responses remained significantly higher (P = 0·014) than at baseline in the AVAC group by week 12; however, the HDM-specific IL-13 and IFN-γ responses were no longer significantly different from baseline. IL-13 (r = 0·46, P < 0·001) and IL-10 (r = 0·27, P = 0·044) responses to HDM were correlated with total immunoglobulin E but not with disease severity. There were no effects of AVAC on mitogen, SEB, TLR-2- or TLR-4-mediated responses. This M. vaccae derivative appeared to modulate responses to HDM selectively, suggesting the capacity for in vivo effects on allergen-specific immune responses.

Harnessing regulatory T cells to suppress asthma: from potential to therapy

Regulatory T cells (Tregs) play an essential role in maintaining the homeostatic balance of immune responses. Asthma is an inflammatory condition of the airways that is driven by dysregulated immune responses toward normally innocuous antigens. Individuals with asthma have fewer and less functional Tregs, which may lead to uncontrolled effector cell responses and promote proasthmatic responses of T helper type 2, T helper 17, natural killer T, antigen-presenting, and B cells. Tregs have the capacity to either directly or indirectly suppress these responses. Hence, the induced expansion of functional Tregs in predisposed or individuals with asthma is a potential approach for the prevention and treatment of asthma. Infection by a number of micro-organisms has been associated with reduced prevalence of asthma, and many infectious agents have been shown to induce Tregs and reduce allergic airways disease in mouse models. The translation of the regulatory and therapeutic properties of infectious agents for use in asthma requires the identification of key modulatory components and the development and trial of effective immunoregulatory therapies. Further translational and clinical research is required for the induction of Tregs to be harnessed as a therapeutic strategy for asthma.