Exploration of the effect of mixed probiotics on microbiota of allergic asthma mice

Saccharomyces boulardii (CNCM I-745) ameliorates Ovalbumin-induced atopic dermatitis by modulating the NF-κB signaling in skin and colon

Atopic dermatitis (AD) is a long-lasting allergic disorder characterized by itching, redness, swelling, dry skin, scaling, inflammation, and tissue damage. The exact cause of AD is still unknown. Steroid medications are frequently utilized in treating AD, but their prolonged use can result in complications. Multiple studies suggest probiotics may regulate the immune system, boost immune functionality, or reduce overactive immune responses. The current study investigated the anti-inflammatory, antioxidant, and immunomodulatory role of Saccharomyces boulardii in Ovalbumin (OVA)-induced AD in a murine model. Balb/c mice were sensitized and challenged with OVA to induce AD-like lesions. S. boulardii 1 × 109 CFU/ml/day/mice was orally administrated either as a pretreatment (administered 7 days before OVA induction and continued till day 28) or concurrent treatment (administered from day 1 and continued till day 28). Dexamethasone (5 mg/kg/day) was used as a standard treatment. S. boulardii alleviated the macroscopic and behavioral changes. Blood inflammatory cells were significantly reduced. Serum IgE levels were decreased. Oxidative stress and histopathological changes (epidermal/dermal thickness, inflammatory cells, collagen deposition) in skin tissue were improved. Similarly, the colon's antioxidant capacity and histological architecture were also maintained. Expression of proinflammatory cytokines like TNF-⍺ and IL-1β were significantly reduced in skin and colon tissue. The probiotic S. boulardii under study reduced inflammation by downregulating NF-κB signaling in both skin and colon tissue. This study provides a basis for a possible gut-skin axis, which can be targeted to relieve AD symptoms.

Roles of Probiotics, Prebiotics, and Postbiotics in B-Cell-Mediated Immune Regulation

Probiotics, prebiotics, and postbiotics can significantly influence B-cell-related diseases through their immunomodulatory effects. They enhance the immune system's function, particularly affecting B cells, which originate in the bone marrow and are crucial for antibody production and immune memory. These substances have therapeutic potential in managing allergies, autoimmune diseases, and inflammatory conditions by regulating the gut microbiota, strengthening epithelial barriers, and directly interacting with various components of the innate and adaptive immune systems. The review highlights the critical need for further research into the precise mechanisms through which probiotics, prebiotics, and postbiotics modulate B cells. Gaining this understanding could facilitate the development of more effective treatments for B-cell-related diseases by harnessing the immunomodulatory properties of these dietary components.

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.

The Link Between Dysbiosis, Inflammation, Oxidative Stress, and Asthma-The Role of Probiotics, Prebiotics, and Antioxidants

Background: Asthma (a chronic inflammatory disease of the airways) is characterized by a variable course, response to treatment, and prognosis. Its incidence has increased significantly in recent decades. Unfortunately, modern lifestyle and environmental factors contribute to the further increase in the incidence of this disease. Progressive industrialization and urbanization, widespread use of antibiotic therapy, excessive sterility and inappropriate, highly processed diets are some of the many risk factors that are relevant today. Over the years, a lot of evidence has been gathered showing the influence of microorganisms of the gut or airways on human health. Studies published in recent years indicate that dysbiosis (microbial imbalance) and oxidative stress (pro-oxidant-antioxidant imbalance) are important elements of the pathogenesis of this inflammatory disease. Scientists have attempted to counteract the effects of this process by using probiotics, prebiotics, and antioxidants. The use of probiotic microorganisms positively modulates the immune system by maintaining homeostasis between individual fractions of immune system cells. Moreover, recently conducted experiments have shown that probiotics have antioxidant, anti-inflammatory, and protective properties in oxidative stress (OS). The aim of this study is to present the current state of knowledge on the role of dysbiosis and OS in the pathogenesis of asthma. Conclusions: This review highlights the importance of using probiotics, prebiotics, and antioxidants as potential strategies to support the treatment and prevention of this disease.

The role of DC subgroups in the pathogenesis of asthma

Dendritic cells (DCs), specialized antigen-presenting cells of the immune system, act as immunomodulators in diseases of the immune system, including asthma. The understanding of DC biology has evolved over the years to include multiple subsets of DCs with distinct functions in the initiation and maintenance of asthma. Moreover, most strategies for treating asthma with relevant therapeutic agents that target DCs have been initiated from the study of DC function. We discussed the pathogenesis of asthma (including T2-high and T2-low), the roles played by different DC subpopulations in the pathogenesis of asthma, and the therapeutic strategies centered around DCs. This study will provide a scientific theoretical basis for current asthma treatment, provide theoretical guidance and research ideas for developing and studying therapeutic drugs targeting DC, and provide more therapeutic options for the patient population with poorly controlled asthma symptoms.

CCAAT/enhancer-binding protein α-dependent regulation of granule formation in mast cells by intestinal bacteria

The antiallergic effects of gut microbiota have been attracting attention in recent years, but the underlying cellular and molecular mechanisms have not yet been fully understood. In this study, we aimed to investigate these mechanisms specifically focusing on mast cells. Mast cells retain intracellular granules containing various inflammatory mediators such as histamine, which are released outside the cells upon IgE and allergen stimulation. We previously reported that increased expression of the transcription factor, CCAAT/enhancer-binding protein α (C/EBPα), suppresses granule formation in mast cells and that Lacticaseibacillus casei JCM1134T (LC) upregulates C/EBPα levels. Here, granule formation in mouse bone marrow-derived mast cells was suppressed in a MyD88-dependent manner after LC treatment due to C/EBPα-dependent downregulation of the genes encoding serglycin (SRGN) and mast cell protease 4 (Mcpt4). Furthermore, C/EBPα expression was regulated by DNA methylation in the 5' region far upstream of the transcription start site. LC suppressed DNA methylation of specific CpG motifs in the 5' region of the C/EBPα gene. These results conclude that specific gut microbial components, such as those from LC, suppress granule formation in mast cells by inhibiting SRGN and Mcpt4 expression via reduced C/EBPα gene methylation.

From bench to bedside: an interdisciplinary journey through the gut-lung axis with insights into lung cancer and immunotherapy

This comprehensive review undertakes a multidisciplinary exploration of the gut-lung axis, from the foundational aspects of anatomy, embryology, and histology, through the functional dynamics of pathophysiology, to implications for clinical science. The gut-lung axis, a bidirectional communication pathway, is central to understanding the interconnectedness of the gastrointestinal- and respiratory systems, both of which share embryological origins and engage in a continuous immunological crosstalk to maintain homeostasis and defend against external noxa. An essential component of this axis is the mucosa-associated lymphoid tissue system (MALT), which orchestrates immune responses across these distant sites. The review delves into the role of the gut microbiome in modulating these interactions, highlighting how microbial dysbiosis and increased gut permeability ("leaky gut") can precipitate systemic inflammation and exacerbate respiratory conditions. Moreover, we thoroughly present the implication of the axis in oncological practice, particularly in lung cancer development and response to cancer immunotherapies. Our work seeks not only to synthesize current knowledge across the spectrum of science related to the gut-lung axis but also to inspire future interdisciplinary research that bridges gaps between basic science and clinical application. Our ultimate goal was to underscore the importance of a holistic understanding of the gut-lung axis, advocating for an integrated approach to unravel its complexities in human health and disease.

Bifidobacterium animalis subsp. lactis CCFM1274 relieved allergic asthma symptoms by modifying intestinal tryptophan metabolism in mice

Approximately two-thirds of patients with asthma, a common inflammatory airway disease, are thought to present with allergies. Probiotics and tryptophan metabolites are becoming increasingly important in treating allergic asthma. This study aimed to identify potential probiotic strains and tryptophan metabolites that could alleviate asthma symptoms. Based on in vitro fermentation experiments, we evaluated variations in probiotic capacity to metabolize tryptophan. Of the eight tested strains, Bifidobacterium animalis subsp. lactis CCFM1274 produced relatively high levels of indole-3-carboxaldehyde (I3C). A mouse model of allergic asthma was established by oral administration of ovalbumin (OVA) and was subjected to oral administration of probiotics. The results demonstrated that treatment with CCFM1274 reduced the tendency for body weight loss and mortality in OVA-induced asthmatic mice. Ingestion of CCFM1274 improved the infiltration of perivascular and peribronchial inflammatory cells in the lung sections stained with hematoxylin and eosin (H&E). This outcome was accompanied by a reduction in the serum levels of OVA-specific immunoglobulin E (OVA-sIgE) and in the levels of IL-10 and IL-17 in the bronchoalveolar lavage fluid (BALF). The linear discriminant analysis effect size (LEfSe) of the gut microbiota showed that CCFM1274 increased the relative abundance of Bifidobacterium. In conclusion, CCFM1274 remodeled intestinal tryptophan metabolism in mice and contributed to the improvement of allergic asthma.

Can probiotics be used in the prevention and treatment of bronchial asthma?

Asthma is a lifelong condition with varying degrees of severity and susceptibility to symptom control. Recent studies have examined the effects of individual genus, species, and strains of probiotic microorganisms on the course of asthma. The present review aims to provide an overview of current knowledge on the use of probiotic microorganisms, mainly bacteria of the genus Lactobacillus and Bifidobacterium, in asthma prevention and treatment. Recent data from clinical trials and mouse models of allergic asthma indicate that probiotics have therapeutic potential in this condition. Animal studies indicate that probiotic microorganisms demonstrate anti-inflammatory activity, attenuate airway hyperresponsiveness (AHR), and reduce airway mucus secretion. A randomized, double-blind, placebo-controlled human trials found that combining multi-strain probiotics with prebiotics yielded promising outcomes in the treatment of clinical manifestations of asthma. It appears that probiotic supplementation is safe and significantly reduces the frequency of asthma exacerbations, as well as improved forced expiratory volume and peak expiratory flow parameters, and greater attenuation of inflammation. Due to the small number of available clinical trials, and the use of a wide range of probiotic microorganisms and assessment methods, it is not possible to draw clear conclusions regarding the use of probiotics as asthma treatments.

Effect of Mixed Probiotics on Ovalbumin-Induced Atopic Dermatitis in Juvenile Mice

Atopic dermatitis is one of the most common dermatologic problems, especially in children. Given the ability of symbiotic microorganisms in modulating the immune system, probiotics administration has been studied in previous research in the management of atopic dermatitis. However, there are conflicting results between studies. In this study, we aimed to assess the effectiveness of mixed probiotics as a treatment option for atopic dermatitis induced by ovalbumin. BALB/c juvenile mice were classified and divided into the ovalbumin group, mixed probiotic group (ovalbumin + LK), and control group. Except for the control group, all mice were sensitized with ovalbumin to establish a model of atopic dermatitis. The mixed probiotics were given by gavage for 14 days. Mice body weight, skin lesions, skin inflammation, ovalbumin-specific Ig, the number of Treg and CD103+DC, and the expression level of PD-1/PD-L1 were examined. The results showed that mixed probiotics can improve body weight and alleviate skin symptoms. Mixed probiotics reduced serum Th2 inflammatory factors, eosinophils, mast cell degranulation, mast cell count, and the expression of ovalbumin-specific immunoglobulin E/G1 and increased the anti-inflammatory cytokine interleukin-10, Treg cells, CD103+DC cells, and the expression level of PD-1/PD-L1. These findings suggest that mixed probiotics could be a viable treatment option for atopic dermatitis and provide insight into the underlying mechanisms involved.

Gut microecological regulation on bronchiolitis and asthma in children: A review

INTRODUCTION

Asthma and bronchiolitis in children are considered common clinical problems associated with gut microbiota. However, the exact relationship between gut microbiota and the above-mentioned diseases remains unclear. Here, we discussed recent advances in understanding the potential mechanism underlying immune regulation of gut microbiota on asthma and bronchiolitis in children as well as the role of the gut-lung axis.

METHODS

We retrieved and assessed all relevant original articles related to gut microbiota, airway inflammation-induced wheezing in children, and gut-lung axis studies from databases that have been published so far, including PubMed/MEDLINE, Scopus, Google Scholar, China National Knowledge Infrastructure (CNKI) and the Wanfang Database.

RESULTS

The infant period is critical for the development of gut microbiota, which can be influenced by gestational age, delivery mode, antibiotic exposure and feeding mode. The gut microbiota in children with asthma and bronchiolitis is significantly distinct from those in healthy subjects. Gut microbiota dysbiosis is implicated in asthma and bronchiolitis in children. The presence of intestinal disturbances in lung diseases highlights the importance of the gut-lung axis.

CONCLUSION

Gut microbiota dysbiosis potentially increases the risk of asthma and bronchiolitis in children. Moreover, a deeper understanding of the gut-lung axis with regard to the gut microbiota of children with respiratory diseases could contribute to clinical practice for pulmonary diseases.

A steroid-resistant cockroach allergen model is associated with lung and cecal microbiome changes

The pathogenesis of asthma has been partially linked to lung and gut microbiome. We utilized a steroid-resistant chronic model of cockroach antigen-induced (CRA) asthma with corticosteroid (fluticasone) treatment to examine lung and gut microbiome during disease. The pathophysiology assessment demonstrated that mucus and airway hyperresponsiveness were increased in the chronic CRA with no alteration in the fluticasone (Flut)-treated group, demonstrating steroid resistance. Analysis of mRNA from lungs showed no decrease of MUC5AC or Gob5 in the Flut-treated group. Furthermore, flow-cytometry in lung tissue showed eosinophils and neutrophils were not significantly reduced in the Flut-treated group compared to the chronic CRA group. When the microbiome profiles were assessed, data showed that only the Flut-treated animals were significantly different in the gut microbiome. Finally, a functional analysis of cecal microbiome metabolites using PiCRUSt showed several biosynthetic pathways were significantly enriched in the Flut-treated group, with tryptophan pathway verified by ELISA with increased kynurenine in homogenized cecum samples. While the implications of these data are unclear, they may suggest a significant impact of steroid treatment on future disease pathogenesis through microbiome and associated metabolite pathway changes.

Heat-Killed Bifidobacterium longum BBMN68 in Pasteurized Yogurt Alleviates Mugwort Pollen-Induced Allergic Airway Responses through Gut Microbiota Modulation in a Murine Model

Many probiotic bacteria have been proven to prevent allergic airway responses through immunomodulation. This study was conducted to evaluate the effects of heat-killed Bifidobacterium longum BBMN68 (BBMN68) in pasteurized yogurt on the alleviation of mugwort pollen (MP)-induced allergic inflammation. BALB/c mice aged 5-6 weeks were randomly assigned and fed pasteurized yogurt containing heat-killed BBMN68 for 27 days, followed by allergic sensitization and challenge with MP extract. The allergic mice that received pasteurized yogurt containing heat-killed BBMN68 had improved immune status, including a lower serum IgE level, decreased serum interleukin (IL)-4, IL-5, and IL-13 concentrations, and alleviated airway inflammation manifested by increased macrophage and decreased eosinophil and neutrophil counts in BALF, as well as airway remodeling and suppressed peribronchial cellular infiltration. Moreover, oral administration of pasteurized yogurt containing heat-killed BBMN68 significantly modulated gut microbiota composition by influencing the proportion of beneficial genera associated with inflammation and immunity, such as Lactobacillus, Candidatus_Saccharimonas, Odoribacter, and Parabacteroides, which also negatively correlated with serum IgE and Th2 cytokine levels. These results demonstrated that pasteurized yogurt containing heat-killed BBMN68 had mitigative effects on allergic airway inflammation, likely through maintaining the systemic Th1/Th2 immune balance by altering the structure and function of the gut microbiota.

Heat-Killed Bifidobacterium longum BBMN68 in Pasteurized Yogurt Alleviates Mugwort Pollen-Induced Allergic Airway Responses through Gut Microbiota Modulation in a Murine Model

Many probiotic bacteria have been proven to prevent allergic airway responses through immunomodulation. This study was conducted to evaluate the effects of heat-killed Bifidobacterium longum BBMN68 (BBMN68) in pasteurized yogurt on the alleviation of mugwort pollen (MP)-induced allergic inflammation. BALB/c mice aged 5-6 weeks were randomly assigned and fed pasteurized yogurt containing heat-killed BBMN68 for 27 days, followed by allergic sensitization and challenge with MP extract. The allergic mice that received pasteurized yogurt containing heat-killed BBMN68 had improved immune status, including a lower serum IgE level, decreased serum interleukin (IL)-4, IL-5, and IL-13 concentrations, and alleviated airway inflammation manifested by increased macrophage and decreased eosinophil and neutrophil counts in BALF, as well as airway remodeling and suppressed peribronchial cellular infiltration. Moreover, oral administration of pasteurized yogurt containing heat-killed BBMN68 significantly modulated gut microbiota composition by influencing the proportion of beneficial genera associated with inflammation and immunity, such as Lactobacillus, Candidatus_Saccharimonas, Odoribacter, and Parabacteroides, which also negatively correlated with serum IgE and Th2 cytokine levels. These results demonstrated that pasteurized yogurt containing heat-killed BBMN68 had mitigative effects on allergic airway inflammation, likely through maintaining the systemic Th1/Th2 immune balance by altering the structure and function of the gut microbiota.

Ablation of CD226 on CD4+ T cells modulates asthma progress associated with altered IL-10 response and gut microbiota

To investigate the role of the costimulatory molecule CD226 in asthma pathogenesis, we produced a CD4⁺ T-cell-specific CD226 knockout mice model (Cd226^ΔCD4) and induced airway allergic inflammation by administering ovalbumin (OVA). Our results revealed alleviated lung inflammation, decreased levels of OVA-specific IgE, and increased levels of IL-10 in the serum of Cd226^ΔCD4 mice (P < 0.05). Moreover, IL-10 levels in CD4⁺ T cells were significantly elevated in the mediastinal lymph node, spleen, and Peyer's patches in the Cd226^ΔCD4 mice compared with those in controls (P < 0.05 to P < 0.01). Notably, there was a significantly higher IL-10 mRNA levels in the large intestine of the mice (P < 0.05). The protective effect of CD226 deficiency is also associated with the accumulation of gut TCRγδ⁺ intraepithelial lymphocytes and reversion of the gut microbiome dysbiosis. The Bacteroidetes-to-Firmicutes ratio and the abundance of Akkermansia increased in the absence of CD226 after OVA treatment. Our data reveal the synchronous changes in the lung and intestine in OVA-treated CD226-knockout mice, supporting the gut-lung axis concept and providing evidence for novel therapeutic approaches for asthma.

Deducing the Interplay Between Gut Flora and Respiratory Diseases: A New Therapeutic Strategy?

The gastrointestinal system, also referred to as the gut, is a universe that colonizes trillions of microbes. In addition to its digestive functions, the gut represents a biosystem that determines all the health vectors. It is now recognized as one of the body's defense systems, and good gut health regulates the body's immune responses. Disturbance of this barrier can trigger many diseases, including respiratory tract infections, as there is a close correlation between the gut microbiome and the chances of triggering illness. This review investigates the various factors affecting the gut microbiome, the diseases that can result from the dysregulation of the same, and their molecular mechanisms. The most basic solution to tackle this problem is to maintain the gut microbiome at the desired level. Timely diagnosis and interventions are needed for the proper management of the ensuing conditions. It is important to address the effects of factors on the gut microbiome and thereby regulate this level. The study also found that dysregulation in the system can lead to various diseases such as asthma, COPD, lung cancer following their respective pathways. In short, this paper reinforces the importance of the gut microbiome, the need to maintain its average level, and the need for proper interventions to treat the consequences. The manuscript posit that medications, diet as well and good physiological conditions of the human body can alter the microbiome and can ward off respiratory infections.

Effect of Bifidobacterium animalis subsp. lactis SF on enhancing the tumor suppression of irinotecan by regulating the intestinal flora

The gut microbiota plays a role in tumor therapy by participating in immune regulation. Here, we demonstrated through 8-day probiotic supplementation experiments and fecal microbiota transplantation experiments that Bifidobacterium animalis subsp. lactis SF enhanced the antitumor effect of irinotecan and prevented the occurrence of intestinal damage by modulating the gut microbiota and reducing the relative abundance of pro-inflammatory microbiota. Therefore, the intestinal inflammation was inhibited, the TGF-β leakage was reduced, and the PI3K/AKT pathway activation was inhibited. Thus, the tumor apoptotic autophagy was finally promoted. Simultaneously, the reduction of TGF-β relieved the immunosuppression caused by CPT-11, promoted the differentiation of CD4⁺ and CD8⁺ T cells in tumor tissue, and consequently inhibited tumor growth and invasion. This study disclosed the mechanism of B. lactis SF assisting CPT-11 in antitumor activity and suggested that B. lactis SF plays a new role in anticancer effects as a nutritional intervention.

Effect of Probiotics on Respiratory Tract Allergic Disease and Gut Microbiota

Allergy is a hypersensitivity reaction triggered by specific cell or antibody-mediated immune mechanisms. Allergies have increased in industrialized countries in recent decades. The rise in allergic respiratory diseases such as allergic rhinitis (AR) and allergic asthma (AA) is a potential threat to public health. Searches were conducted using PubMed, Google Scholar and Medline using the following key terms: allergic rhinitis OR asthma AND probiotics, allergic airway inflammation AND immune disorders, probiotics OR gut microbiota AND allergic disease, probiotics AND inflammatory. Studies from all years were included, specifically those published within the last 10 years. Some review articles and their reference lists were searched to identify related articles. The role of microbiota in respiratory allergic diseases has attracted more and more attention. Pieces of evidence suggested that the development of allergic diseases causes a possible imbalance in the composition of the gut microbiota. Compared to colonized mice, germ-free mice exhibit exaggerated allergic airway responses, suggesting that microbial host interactions play an important role in the development of allergic diseases. Probiotics modulate both the innate and adaptive inflammatory immune responses, often used as dietary supplements to provide health benefits in gastrointestinal disorders. Probiotics may serve as immunomodulators and activators of host defense pathways. Besides, oral probiotics can modulate the immune response in the respiratory system. Recently, studies in humans and animals have demonstrated the role of probiotic in RA and AA. To understand the characterization, microbiota, and the potential role of probiotics intervention of AA/AR, this review provides an overview of clinical features of AA and AR, probiotics for the prevention and treatment of AR, AA, changes in gut microbiota, and their mechanisms of action.

The Immune Mechanisms of Severe Equine Asthma-Current Understanding and What Is Missing

Severe equine asthma is a chronic respiratory disease of adult horses, occurring when genetically susceptible individuals are exposed to environmental aeroallergens. This results in airway inflammation, mucus accumulation and bronchial constriction. Although several studies aimed at evaluating the genetic and immune pathways associated with the disease, the results reported are inconsistent. Furthermore, the complexity and heterogeneity of this disease bears great similarity to what is described for human asthma. Currently available studies identified two chromosome regions (ECA13 and ECA15) and several genes associated with the disease. The inflammatory response appears to be mediated by T helper cells (Th1, Th2, Th17) and neutrophilic inflammation significantly contributes to the persistence of airway inflammatory status. This review evaluates the reported findings pertaining to the genetical and immunological background of severe equine asthma and reflects on their implications in the pathophysiology of the disease whilst discussing further areas of research interest aiming at advancing treatment and prognosis of affected individuals.

Microbiome First Medicine in Health and Safety

Microbiome First Medicine is a suggested 21st century healthcare paradigm that prioritizes the entire human, the human superorganism, beginning with the microbiome. To date, much of medicine has protected and treated patients as if they were a single species. This has resulted in unintended damage to the microbiome and an epidemic of chronic disorders [e.g., noncommunicable diseases and conditions (NCDs)]. Along with NCDs came loss of colonization resistance, increased susceptibility to infectious diseases, and increasing multimorbidity and polypharmacy over the life course. To move toward sustainable healthcare, the human microbiome needs to be front and center. This paper presents microbiome-human physiology from the view of systems biology regulation. It also details the ongoing NCD epidemic including the role of existing drugs and other factors that damage the human microbiome. Examples are provided for two entryway NCDs, asthma and obesity, regarding their extensive network of comorbid NCDs. Finally, the challenges of ensuring safety for the microbiome are detailed. Under Microbiome-First Medicine and considering the importance of keystone bacteria and critical windows of development, changes in even a few microbiota-prioritized medical decisions could make a significant difference in health across the life course.