Gut Microbiota and Fecal Microbiota Transplantation in Patients with Food Allergies: A Systematic Review

Fecal microbiota transplantation in allergic diseases

Microorganisms such as bacteria, fungi, viruses, parasites living in the human intestine constitute the human intestinal microbiota. Dysbiosis refers to compositional and quantitative changes that negatively affect healthy gut microbiota. In recent years, with the demonstration that many diseases are associated with dysbiosis, treatment strategies targeting the correction of dysbiosis in the treatment of these diseases have begun to be investigated. Faecal microbiota transplantation (FMT) is the process of transferring faeces from a healthy donor to another recipient in order to restore the gut microbiota and provide a therapeutic benefit. FMT studies have gained popularity after probiotic, prebiotic, symbiotic studies in the treatment of dysbiosis and related diseases. FMT has emerged as a potential new therapy in the treatment of allergic diseases as it is associated with the maintenance of intestinal microbiota and immunological balance (T helper 1/T helper 2 cells) and thus suppression of allergic responses. In this article, the definition, application, safety and use of FMT in allergic diseases will be discussed with current data.

Live bacteria in gut microbiome dictate asthma onset triggered by environmental particles via modulation of DNA methylation in dendritic cells

Despite broad knowledge of the pathogenesis, our understanding of the origin of allergy and asthma remains poor, preventing etiotropic treatments. The gut microbiome is seen to be altered in asthmatics; however, proof of causality of the microbiome alterations is lacking. We report on gut microbiome transplantation (GMT) from mice predisposed to asthma by maternal exposure to pro-allergy environmental particles into naive recipients. This GMT confers asthma predisposition, and the effect is abrogated by gamma sterilization of the transplant material or by co-administration of antibacterials, indicating that viable bacteria are mediating the effect. Metagenomics identifies key changes in the "pro-asthma" microbiome, and metabolomics links the identified species to altered production of butyrate known to act on immune cells and epigenetic mechanisms. We further show that transplant recipients develop DNA methylation alterations in dendritic cells. Finally, dendritic cells with an altered methylome present allergen to T cells, and this effect is abrogated by an epigenetically acting drug in vitro.

Gut Microbiome Modulation in Allergy Treatment: The Role of Fecal Microbiota Transplantation

The prevalence of allergic diseases has been rising, paralleling lifestyle changes and environmental exposures that have altered human microbiome composition. This review article examines the intricate relationship between the gut microbiome and allergic diseases, emphasizing the potential of fecal microbiota transplantation as a promising novel treatment approach. It explains how reduced microbial exposure in modern societies contributes to immune dysregulation and the increasing incidence of allergies. The discussion also addresses immune homeostasis and its modulation by the gut microbiome, highlighting the shift from eubiosis to dysbiosis in allergic conditions. Furthermore, this article reviews existing studies and emerging research on the role of fecal microbiota transplantation in restoring microbial balance, providing insights into its mechanisms, efficacy, and safety.

The Etiology of IgE-Mediated Food Allergy: Potential Therapeutics and Challenges

Immunoglobulin E (IgE)-mediated food allergy has been dramatically increasing in incidence over the last few decades. The combinations of both genetic and environmental factors that affect the microbiome and immune system have demonstrated significant roles in its pathogenesis. The morbidity, and at times mortality, that occurs as the result of this specific, reproducible, but impaired immune response is due to the nature of the shift from a regulatory T (Treg) cellular response to a T helper 2 (Th2) cellular response. This imbalance caused by food allergens results in an interleukin (IL)-4 and IL-13 dominant environment that drives B cell activation and differentiation into IgE-producing plasma cells. The resulting symptoms can range from mild to more severe anaphylaxis, and even death. Current therapeutic strategies involve avoidance and broad symptom management upon accidental exposure; however, no definitive cure exists. This narrative review highlights how the elucidation of the pathogenesis of IgE-mediated food allergy resulted in the development of therapeutics that are more specific to these individual receptors and molecules which have been relatively successful in mitigating this potentially life-threatening allergic response. However, potential adverse effects and re-sensitization following the conclusion of treatment has urged the need for improved therapeutic methods. Therefore, given the understanding of their mechanism of action and the overlap with the mechanism of IgE-mediated food allergies, probiotics and small molecule natural compounds may provide novel therapeutic and preventative strategies. This is compelling, as they have demonstrated success in clinical trials and may provide hope to improve quality of life in allergy patients.

Amelioration Effect of Lactobacillus kefiranofaciens ZW3 on Ovalbumin-Induced Allergic Symptoms in BALB/c Mice

Previous studies have shown that supplementation with specific probiotics can be used to alleviate allergy symptoms. The purpose of this study was to evaluate the anti-allergic effects of Lactobacillus kefiranofaciens ZW3 (ZW3) in ovalbumin (OVA)-induced allergic mice. The mice were divided into six groups: the food allergy group, positive group (Lactobacillus rhamnosus GG), low-dose ZW3 group, middle-dose ZW3 group, high-dose ZW3 group, and the control group involving healthy mice. BALB/c mice were intraperitoneally injected with OVA/complete Freund's adjuvant (CFA) for allergy sensitization. Probiotics were administered orally once every two days in the probiotic-treated groups. The allergic score, serum OVA-sIgE, body mass, thymus, and spleen indexes were detected on day 22, and the relative mRNA expression of inflammatory cytokines was detected via RT-qPCR. The results suggest that the body weight and thymus index returned to normal levels; allergy scores, serum OVA-sIgE, IL-4, IL-5, and IL-10 expression decreased; and IFN-γ and IL-2 increased significantly in the ZW3 group compared with the allergy group. Furthermore, ZW3 decreased Muribaculaceae and Ruminococcaceae abundance and increased Lachnospiraceae abundance in the intestinal flora. In summary, ZW3 induced anti-allergic effects by increasing Th1 cytokines and decreasing Th2 cytokines, which can remarkably ameliorate the symptoms of an ovalbumin-induced food allergy.

Safety and efficacy of fecal microbiota transplantation (FMT) as a modern adjuvant therapy in various diseases and disorders: a comprehensive literature review

The human gastrointestinal (GI) tract microbiome is a complex and all-encompassing ecological system of trillions of microorganisms. It plays a vital role in digestion, disease prevention, and overall health. When this delicate balance is disrupted, it can lead to various health issues. Fecal microbiota transplantation (FMT) is an emerging therapeutic intervention used as an adjuvant therapy for many diseases, particularly those with dysbiosis as their underlying cause. Its goal is to restore this balance by transferring fecal material from healthy donors to the recipients. FMT has an impressive reported cure rate between 80% and 90% and has become a favored treatment for many diseases. While FMT may have generally mild to moderate transient adverse effects, rare severe complications underscore the importance of rigorous donor screening and standardized administration. FMT has enormous potential as a practical therapeutic approach; however, additional research is required to further determine its potential for clinical utilization, as well as its safety and efficiency in different patient populations. This comprehensive literature review offers increased confidence in the safety and effectiveness of FMT for several diseases affecting the intestines and other systems, including diabetes, obesity, inflammatory and autoimmune illness, and other conditions.

Beyond Antibiotics: What the Future Holds

The prevalence of multidrug resistance (MDR) and stagnant drug-development pipelines have led to the rapid rise of hard-to-treat antibiotic-resistant bacterial infections. These infectious diseases are no longer just nosocomial but are also becoming community-acquired. The spread of MDR has reached a crisis level that needs immediate attention. The landmark O'Neill report projects that by 2050, mortality rates associated with MDR bacterial infections will surpass mortality rates associated with individuals afflicted with cancer. Since conventional antimicrobials are no longer very reliable, it is of great importance to investigate different strategies to combat these life-threatening infectious diseases. Here, we provide an overview of recent advances in viable alternative treatment strategies mainly targeting a pathogen's virulence capability rather than viability. Topics include small molecule and immune inhibition of virulence factors, quorum sensing (QS) quenching, inhibition of biofilm development, bacteriophage-mediated therapy, and manipulation of an individual's macroflora to combat MDR bacterial infections.

Link between gut microbiota dysbiosis and childhood asthma: Insights from a systematic review

Asthma, a chronic inflammatory disorder of the airways, is a prevalent childhood chronic disease with a substantial global health burden. The complex etiology and pathogenesis of asthma involve genetic and environmental factors, posing challenges in diagnosis, severity prediction, and therapeutic strategies. Recent studies have highlighted the significant role of the gut microbiota and its interaction with the immune system in the development of asthma. Dysbiosis, an imbalance in microbial composition, has been associated with respiratory diseases through the gut-lung axis. This axis is an interaction between the gut and lungs, allowing microbial metabolites to influence the host immune system. This systematic review examines the association between gut microbiota composition, measured using 16S rRNA sequencing, during infancy and childhood, and the subsequent development of atopic wheeze and asthma. The results suggest that higher alpha diversity of bacteria such as Bifidobacterium, Faecalibacterium, and Roseburia may have protective effects against asthmatic outcomes. Conversely, lower relative abundances of bacteria like Bacteroides and certain fungi, including Malassezia, were associated with asthma. These findings highlight the potential of early screening and risk assessment of gut microbiota to identify individuals at risk of asthma. Furthermore, investigations targeting gut microbiota, such as dietary modifications and probiotic supplementation, may hold promise for asthma prevention and management. Future research should focus on identifying specific microbial signatures associated with asthma susceptibility and further investigate approaches like fecal microbiota transplantation. Understanding the role of gut microbiota in asthma pathogenesis can contribute to early detection and development of interventions to mitigate the risk of asthmatic pathogenesis in childhood.

Bringing gut microbiota into the spotlight of clinical research and medical practice

Despite the increasing scientific interest and expanding role of gut microbiota (GM) in human health, it is rarely reported in case reports and deployed in clinical practice. Proteins and metabolites produced by microbiota contribute to immune system development, energy homeostasis and digestion. Exo- and endogenous factors can alter its composition. Disturbance of microbiota, also known as dysbiosis, is associated with various pathological conditions. Specific bacterial taxa and related metabolites are involved in disease pathogenesis and therefore can serve as a diagnostic tool. GM could also be a useful prognostic factor by predicting future disease onset and preventing hospital-associated infections. Additionally, it can influence response to treatments, including those for cancers, by altering drug bioavailability. A thorough understanding of its function has permitted significant development in therapeutics, such as probiotics and fecal transplantation. Hence, GM should be considered as a ground-breaking biological parameter, and it is advisable to be investigated and reported in literature in a more consistent and systematic way.

Utilization of the microbiome in personalized medicine

Inter-individual human variability, driven by various genetic and environmental factors, complicates the ability to develop effective population-based early disease detection, treatment and prognostic assessment. The microbiome, consisting of diverse microorganism communities including viruses, bacteria, fungi and eukaryotes colonizing human body surfaces, has recently been identified as a contributor to inter-individual variation, through its person-specific signatures. As such, the microbiome may modulate disease manifestations, even among individuals with similar genetic disease susceptibility risks. Information stored within microbiomes may therefore enable early detection and prognostic assessment of disease in at-risk populations, whereas microbiome modulation may constitute an effective and safe treatment tailored to the individual. In this Review, we explore recent advances in the application of microbiome data in precision medicine across a growing number of human diseases. We also discuss the challenges, limitations and prospects of analysing microbiome data for personalized patient care.

Oral administration of egg ovalbumin allergen induces dysregulation of tryptophan metabolism in sensitized BALB/c mice

Food allergy (FA), triggered by specific dietary allergens, has emerged as a substantial global concern for food safety and public health. While studies have elucidated changes in immune cells and cytokines associated with allergen exposure, a comprehensive analysis of the host's metabolic features and the interaction between metabolites and the gut microbiota has not been conducted. In this study, egg allergen ovalbumin (OVA) was administered by the oral route to sensitized BALB/c mice to faithfully replicate key aspects of human FA, including severe allergic diarrhea, mast cell infiltration, and elevated levels of serum IgE, mMCPT-1, and Th2 cell hallmark cytokines (such as IL-4, IL-5, and IL-13). Furthermore, the untargeted and targeted metabolomic analyses indicated that FA in mice precipitated a substantial decrease in the tryptophan metabolites indole-3-acrylic acid (IA) and indole-3-lactic acid (ILA). The integration of shotgun metagenome and metabolome data further unveiled that the dysregulation of indole metabolism is related to a decline in the abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium. Additionally, disruption of the tryptophan indole derivative pathway compromises the maintenance of intestinal mucosal function through the AHR signaling pathway, manifested by decreased expression of Reg3g and IL22. Taken together, this study demonstrated that the anaphylaxis triggered by oral ingestion of food allergens can lead to disruptions in tryptophan metabolism, consequently impairing intestinal immune homeostasis.

The Future of Food Allergy Management: Advancements in Therapies

PURPOSE OF REVIEW

To review current and future treatment options for IgE-mediated food allergy.

RECENT FINDINGS

Recent years have seen major developments in both allergen-specific and allergen-non-specific treatment options, with the first FDA-approved peanut oral immunotherapy (OIT) product becoming available in 2020. In addition to OIT, other immunotherapy modalities, biologics, adjunct therapies, and novel therapeutics are under investigation. Food allergy is a potentially life-threatening condition associated with a significant psychosocial impact. Numerous products and protocols are under investigation, with most studies focusing on OIT. A high rate of adverse events, need for frequent office visits, and cost remain challenges with OIT. Further work is needed to unify outcome measures, develop treatment protocols that minimize adverse events, establish demographic and clinical factors that influence candidate selection, and identify patient priorities.

Feast for thought: A comprehensive review of food allergy 2021-2023

A review of the latest publications in food allergy over the past couple of years confirmed that food allergy is a major public health concern, affecting about 8% of children and 10% of adults in developed countries. The prevalence of food allergy varies around the world, with the increase being driven mainly by environmental factors, possibly together with genetic susceptibility to environmental changes. A precise diagnosis of food allergy is extremely important. Both new tests (eg, the basophil activation test) and improved optimization of information provided by existing tests (eg, the skin prick test and measurement of specific IgE level) can contribute to improving the accuracy and patients' comfort of food allergy diagnosis. Understanding the underlying immune mechanisms is fundamental to designing allergen-specific treatments that can be safe and effective in the long term. New discoveries of the immune response to food allergens, including T-cell and B-cell responses, have emerged. Novel therapeutic approaches are being trialed at various stages of development as attempts to allow for more active intervention to treat food allergy. Prevention is key to reducing the increase in prevalence. Early introduction of allergenic foods seems to be the most effective intervention, but others are being studied, and will, it is hoped, lead to modification of the epidemiologic trajectory of food allergy over time.

Short-chain fatty acid - A critical interfering factor for allergic diseases

Allergy is a growing global public health problem with a high socio-economic impact. The incidence of allergic diseases is increasing year by year, which has attracted more and more attention. In recent years, a number of epidemiological investigations and gut microbiota studies have shown that gut microbiota dysbiosis is associated with an increased prevalence of various allergic diseases, such as food allergy, asthma, allergic rhinitis, and atopic dermatitis. However, the underlying mechanisms are complex and have not been fully clarified. Metabolites are one of the main ways in which the gut microbiota functions. Short-chain fatty acids (SCFAs) are the main metabolites of intestinal flora fermentation and are beneficial to human health. Studies have shown that SCFAs play an important role in maintaining intestinal homeostasis and regulating immune responses by recognizing receptors and inhibiting histone deacetylases, and are key molecules involved in the occurrence and development of allergic diseases. In addition, research on the regulation of gut microbiota and the application of SCFAs in the treatment of allergic diseases is also emerging. This article reviews the clinical and experimental evidence on the correlation between SCFAs and allergic diseases and the potential mechanisms by which SCFAs regulate allergic diseases. Furthermore, SCFAs as therapeutic targets for allergic diseases are also summarized and prospected.

Update on clinical research for food allergy treatment

The incidence of IgE-mediated food allergy (FA) has continued to increase over the years which places substantial burden on patient health and quality of life. With no cure for this disease, the mainstay of management has been allergen avoidance. However, there have been advancements in FA treatment in recent years with multiple clinical trials utilizing novel and innovative therapeutic strategies. A landmark event came in 2020 with the first drug approval for food allergy with the approval of a product for peanut oral immunotherapy. In addition to oral immunotherapy, different delivery systems of immunotherapy (SLIT, EPIT) are being studied in addition to probiotics, biologic agents - used as monotherapy and as an adjunct, and modified allergens has taken place with the hope to further enhance existing therapeutic options. The hope through these continued developments is for therapies to emerge that will provide a more comprehensive benefit to this patient population.