Emerging pathogenic links between microbiota and the gut-lung axis

The forecasting power of the mucin-microbiome interplay in livestock respiratory diseases

Complex respiratory diseases are a significant challenge for the livestock industry worldwide. These diseases considerably impact animal health and welfare and cause severe economic losses. One of the first lines of pathogen defense combines the respiratory tract mucus, a highly viscous material primarily composed of mucins, and a thriving multi-kingdom microbial ecosystem. The microbiome-mucin interplay protects from unwanted substances and organisms, but its dysfunction may enable pathogenic infections and the onset of respiratory disease. Emerging evidence also shows that noncoding regulatory RNAs might modulate the structure and function of the microbiome-mucin relationship. This opinion paper unearths the current understanding of the triangular relationship between mucins, the microbiome, and noncoding RNAs in the context of respiratory infections in animals of veterinary interest. There is a need to look at these molecular underpinnings that dictate distinct health and disease outcomes to implement effective prevention, surveillance, and timely intervention strategies tailored to the different epidemiological contexts.

Gut microbiota-lncRNA/circRNA crosstalk: implications for different diseases

The gut microbiota features an abundance of diverse microorganisms and represents an important component of human physiology and metabolic homeostasis, indicating their roles in a wide array of physiological and pathological processes in the host. Maintaining balance in the gut microbiota is critical for normal functionality as microbial dysbiosis can lead to the occurrence and development of diseases through various mechanisms. Long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) are non-coding RNAs that perform important regulatory functions for many processes. Furthermore, the gut microbiota and lncRNAs/circRNAs are known to interact in a range of both physiological and pathological activities. In this article, we review existing research relevant to the interaction between the gut microbiota and lncRNAs/circRNAs and investigate the role of their crosstalk in the pathogenesis of different diseases. Studies have shown that, the gut microbiota can target lncRNAs ENO1-IT1, BFAL1, and LINC00152 to regulate colorectal cancer development via various signaling pathways. In addition, the gut microbiota can influence mental diseases and lung tumor metastasis by modulating circRNAs such as circNF1-419, circ_0001239, circHIPK2 and mmu_circ_0000730. These findings provide a theoretical basis for disease prevention and treatment and suggest that gut microbiota-lncRNA/circRNA crosstalk has high clinical value.

The Role of Exhaled Breath Condensate in Chronic Inflammatory and Neoplastic Diseases of the Respiratory Tract

Asthma and chronic obstructive pulmonary disease (COPD) are among the most common chronic respiratory diseases. Chronic inflammation of the airways leads to an increased production of inflammatory markers by the effector cells of the respiratory tract and lung tissue. These biomarkers allow the assessment of physiological and pathological processes and responses to therapeutic interventions. Lung cancer, which is characterized by high mortality, is one of the most frequently diagnosed cancers worldwide. Current screening methods and tissue biopsies have limitations that highlight the need for rapid diagnosis, patient differentiation, and effective management and monitoring. One promising non-invasive diagnostic method for respiratory diseases is the assessment of exhaled breath condensate (EBC). EBC contains a mixture of volatile and non-volatile biomarkers such as cytokines, leukotrienes, oxidative stress markers, and molecular biomarkers, providing significant information about inflammatory and neoplastic states in the lungs. This article summarizes the research on the application and development of EBC assessment in diagnosing and monitoring respiratory diseases, focusing on asthma, COPD, and lung cancer. The process of collecting condensate, potential issues, and selected groups of markers for detailed disease assessment in the future are discussed. Further research may contribute to the development of more precise and personalized diagnostic and treatment methods.

Intestinal microbiota and tuberculosis: Insights from Mendelian randomization

Respiratory tuberculosis (RTB), a global health concern affecting millions of people, has been observationally linked to the gut microbiota, but the depth and nature of this association remain elusive. Despite these findings, the underlying causal relationship is still uncertain. Consequently, we used the Mendelian randomization (MR) method to further investigate this potential causal connection. We sourced data on the gut microbiota from a comprehensive genome-wide association study (GWAS) conducted by the MiBioGen Consortium (7686 cases, and 115,893 controls). For RTB, we procured 2 distinct datasets, labeled the Fingen R9 TBC RESP and Fingen R9 AB1 RESP, from the Finnish Genetic Consortium. To decipher the potential relationship between the gut microbiota and RTB, we employed MR on both datasets. Our primary mode of analysis was the inverse variance weighting (IVW) method. To ensure robustness and mitigate potential confounders, we meticulously evaluated the heterogeneity and potential pleiotropy of the outcomes. In the TBC RESP (RTB1) dataset related to the gut microbiota, the IVW methodology revealed 7 microbial taxa that were significantly associated with RTB. In a parallel vein, the AB1 RESP (RTB2) dataset highlighted 4 microbial taxa with notable links. Notably, Lachnospiraceae UCG010 was consistently identified across both datasets. This correlation was especially evident in the data segments designated Fingen R9 TBC RESP (OR = 1.799, 95% CI = 1.243-2.604) and Finngen R9 AB1 RESP (OR = 2.131, 95% CI = 1.088-4.172). Our study identified a causal relationship between particular gut microbiota and RTB at the level of prediction based on genetics. This discovery sheds new light on the mechanisms of RTB development, which are mediated by the gut microbiota.

Gut microbial metabolites in lung cancer development and immunotherapy: Novel insights into gut-lung axis

Metabolic derivatives of numerous microorganisms inhabiting the human gut can participate in regulating physiological activities and immune status of the lungs through the gut-lung axis. The current well-established microbial metabolites include short-chain fatty acids (SCFAs), tryptophan and its derivatives, polyamines (PAs), secondary bile acids (SBAs), etc. As the study continues to deepen, the critical function of microbial metabolites in the occurrence and treatment of lung cancer has gradually been revealed. Microbial derivates can enter the circulation system to modulate the immune microenvironment of lung cancer. Mechanistically, oncometabolites damage host DNA and promote the occurrence of lung cancer, while tumor-suppresive metabolites directly affect the immune system to combat the malignant properties of cancer cells and even show considerable application potential in improving the efficacy of lung cancer immunotherapy. Considering the crosstalk along the gut-lung axis, in-depth exploration of microbial metabolites in patients' feces or serum will provide novel guidance for lung cancer diagnosis and treatment selection strategies. In addition, targeted therapeutics on microbial metabolites are expected to overcome the bottleneck of lung cancer immunotherapy and alleviate adverse reactions, including fecal microbiota transplantation, microecological preparations, metabolite synthesis and drugs targeting metabolic pathways. In summary, this review provides novel insights and explanations on the intricate interplay between gut microbial metabolites and lung cancer development, and immunotherapy through the lens of the gut-lung axis, which further confirms the possible translational potential of the microbiome metabolome in lung cancer treatment.

Dissecting causal relationships between gut microbiota, blood metabolites, and glioblastoma multiforme: a two-sample Mendelian randomization study

Background

Given the increasing interest in the role of gut microbiota in glioblastoma multiforme (GBM), our objective was to examine the potential causal relationship between gut microbiota and GBM, as well as the mediating effects of specific metabolites.

Methods

A bidirectional two-sample Mendelian randomization (MR) analysis was conducted to investigate the associations between 196 microbial taxa and GBM. A two-step MR technique was used to identify significant mediators in this relationship. Subsequently, a mediation analysis was performed to explore and quantify the mediating effects of specific metabolites on the causal relationship between gut microbiota and GBM.

Results

Five taxa showed significant associations with GBM. Among them, family Victivallaceae [odds ratio (OR): 1.95; 95% confidence interval (CI): 1.21, 3.13; p = 0.005] and genus Lactococcus (OR: 1.81; 95% CI: 1.04, 3.15; p = 0.036) were positively correlated with the risk of GBM, while phylum Cyanobacteria had a protective effect against GBM (OR: 0.45; 95% CI: 0.22, 0.89; p = 0.021). The mediation analysis revealed that the connections among family Victivallaceae, genus Lactococcus, phylum Cyanobacteria and GBM were mediated by Methyl-4-hydroxybenzoate sulfate, phosphoethanolamine and dehydroepiandrosterone sulfate. Each of these accounted for 7.27, 7.98, and 8.65%, respectively.

Conclusion

Our study provides evidence supporting a potential causal association between certain gut microbiota taxa and GBM. The study highlights the central role of gut microbiota in GBM pathogenesis and their interactions with vital serum metabolites. This paves the way for potential novel therapeutic interventions in GBM management.

Effect of a Combination of Lactiplantibacillus plantarum KC3 and Leonurus japonicus Extracts in Respiratory Discomfort: A Randomized, Double-Blind, Placebo-Controlled Trial

The increased global prevalence of chronic respiratory diseases in recent years has caused a substantial public health burden. Lactiplantibacillus plantarum KC3 and Leonurus japonicus Houtt. (LJH) extracts can alleviate respiratory symptoms and improve lung function in vitro and in vivo. However, the clinical efficacy and safety profile of this combination in patients with respiratory diseases remain unclear. Therefore, this multicenter, randomized, double-blind, placebo-controlled clinical trial aimed to evaluate the efficacy and safety of L. plantarum KC3 and LJH extracts in adults with respiratory discomfort. This mixture was termed 'CKDB-315'. Participants, randomly assigned to the CKDB-315 or placebo groups, were treated for 12 weeks. Assessments included the St. George's Respiratory Questionnaire (SGRQ) and the Chronic Obstructive Pulmonary Disease Assessment Test (CAT). The CKDB-315 group showed considerably improved SGRQ and CAT scores compared with the placebo group. Secondary outcomes, including dyspnea, pulmonary function, total antioxidant status, and inflammatory cytokine levels, were consistent with the primary outcomes. Exploratory analyses of the gut microbiota and short-chain fatty acid contents revealed the potential mechanisms underlying the effects of CKDB-315. Finally, safety analysis indicated that CKDB-315 was well tolerated and caused few adverse events. Our findings indicate that CKDB-315 is a promising therapeutic option for respiratory discomfort in adults.

Appendix removal affects the subsequent cancer risk in Asian adults: A territory-wide population-based cohort study

Human appendix is critical for the maintenance of intestinal homeostasis. Appendicectomy has been the optimal treatment of acute appendicitis, yet the cancer incidence after appendix removal remains unclear. In this territory-wide retrospective cohort study, adult participants who underwent appendicectomy from 2000 to 2018 were retrieved from a population database (n = 43,983), while matched reference participants were retrieved as controls (n = 85,853). After appendicectomy, the overall cancer risk was significantly increased (subdistribution hazard ratio (SHR) = 1.124) compared to the non-appendicectomy group. Appendicectomy-treated males had higher cancer risk than males without appendicectomy (SHR = 1.197), while such difference was not observed in female participants. Significant increase in cancer risk was also observed in elder participants (age >60) with appendicectomy (SHR = 1.390). Appendicectomy was positively correlated with the risk of digestive tract and respiratory cancers including colon (SHR = 1.440), pancreas (SHR = 1.930), and trachea, bronchus, and lung (SHR = 1.394). In contrast, the risk of liver cancer was markedly decreased after appendicectomy (SHR = 0.713). In conclusion, we reported the association of appendicectomy with subsequent cancer incidence. These findings highlight the potential complication after appendix removal and the necessity of post-operative management to monitor and prevent long-term adverse events.

Host tracheal and intestinal microbiomes inhibit Coccidioides growth in vitro

Coccidioidomycosis, also known as Valley fever, is a disease caused by the fungal pathogen Coccidioides. Unfortunately, patients are often misdiagnosed with bacterial pneumonia, leading to inappropriate antibiotic treatment. The soil Bacillus subtilis-like species exhibits antagonistic properties against Coccidioides in vitro; however, the antagonistic capabilities of host microbiota against Coccidioides are unexplored. We sought to examine the potential of the tracheal and intestinal microbiomes to inhibit the growth of Coccidioides in vitro. We hypothesized that an uninterrupted lawn of microbiota obtained from antibiotic-free mice would inhibit the growth of Coccidioides, while partial in vitro depletion through antibiotic disk diffusion assays would allow a niche for fungal growth. We observed that the microbiota grown on 2×GYE (GYE) and Columbia colistin and nalidixic acid with 5% sheep's blood agar inhibited the growth of Coccidioides, but microbiota grown on chocolate agar did not. Partial depletion of the microbiota through antibiotic disk diffusion revealed diminished inhibition and comparable growth of Coccidioides to controls. To characterize the bacteria grown and identify potential candidates contributing to the inhibition of Coccidioides, 16S rRNA sequencing was performed on tracheal and intestinal agar cultures and murine lung extracts. We found that the host bacteria likely responsible for this inhibition primarily included Lactobacillus and Staphylococcus. The results of this study demonstrate the potential of the host microbiota to inhibit the growth of Coccidioides in vitro and suggest that an altered microbiome through antibiotic treatment could negatively impact effective fungal clearance and allow a niche for fungal growth in vivo.

IMPORTANCE

Coccidioidomycosis is caused by a fungal pathogen that invades the host lungs, causing respiratory distress. In 2019, 20,003 cases of Valley fever were reported to the CDC. However, this number likely vastly underrepresents the true number of Valley fever cases, as many go undetected due to poor testing strategies and a lack of diagnostic models. Valley fever is also often misdiagnosed as bacterial pneumonia, resulting in 60%-80% of patients being treated with antibiotics prior to an accurate diagnosis. Misdiagnosis contributes to a growing problem of antibiotic resistance and antibiotic-induced microbiome dysbiosis; the implications for disease outcomes are currently unknown. About 5%-10% of symptomatic Valley fever patients develop chronic pulmonary disease. Valley fever causes a significant financial burden and a reduced quality of life. Little is known regarding what factors contribute to the development of chronic infections and treatments for the disease are limited.

Quercetin influences intestinal dysbacteriosis and delays alveolar epithelial cell senescence by regulating PTEN/PI3K/AKT signaling in pulmonary fibrosis

Pulmonary fibrosis is a chronic and progressive lung disease with high mortality. This study aims to explore the protective mechanism of quercetin against pulmonary fibrosis regarding cell senescence and gut microbiota. Rats were intratracheally injected with bleomycin (BLM) to establish a pulmonary fibrosis rat model. RLE-6TN cells were stimulated with BLM to build the model of alveolar epithelial cell senescence, and RLE-6TN-derived conditional medium (CM) was harvested to further culture fibroblasts. Histopathological changes were assessed by H&E and Masson staining. α-SMA expression was assessed by immunofluorescence assay. Senescence-associated β-galactosidase (SA-β-gal) staining and senescence-associated secretory phenotype (SASP) cytokine assay were conducted to assess cellular senescence. Gut microbiota was analyzed by 16S rRNA gene sequencing. The fibrosis-, senescence-, and PTEN/PI3K/AKT signaling-related proteins were examined by western blot. In BLM-induced pulmonary fibrosis rats, quercetin exerted its protective effects by reducing histological injury and collagen deposition, lessening cellular senescence, and regulating gut microbiota. In BLM-induced alveolar epithelial cell senescence, quercetin inhibited senescence, lessened SASP cytokine secretion of alveolar epithelial cells, and further ameliorated collagen deposition in fibroblasts. In addition, quercetin might exert its functional effects by regulating the PTEN/PI3K/AKT signaling pathway. Moreover, quercetin regulated intestinal dysbacteriosis in BLM-induced pulmonary fibrosis rats, especially boosting the abundance of Akkermansia. To conclude, our findings provide an in-depth understanding of the potential mechanism behind the protective role of quercetin against pulmonary fibrosis.

Multikingdom characterization of gut microbiota in patients with rheumatoid arthritis and rheumatoid arthritis-associated interstitial lung disease

Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a serious and common extra-articular disease manifestation. Patients with RA-ILD experience reduced bacterial diversity and gut bacteriome alterations. However, the gut mycobiome and virome in these patients have been largely neglected. In this study, we performed whole-metagenome shotgun sequencing on fecal samples from 30 patients with RA-ILD, and 30 with RA-non-ILD, and 40 matched healthy controls. The gut bacteriome and mycobiome were explored using a reference-based approach, while the gut virome was profiled based on a nonredundant viral operational taxonomic unit (vOTU) catalog. The results revealed significant alterations in the gut microbiomes of both RA-ILD and RA-non-ILD groups compared with healthy controls. These alterations encompassed changes in the relative abundances of 351 bacterial species, 65 fungal species, and 4,367 vOTUs. Bacteria such as Bifidobacterium longum, Dorea formicigenerans, and Collinsella aerofaciens were enriched in both patient groups. Ruminococcus gnavus (RA-ILD), Gemmiger formicilis, and Ruminococcus bromii (RA-non-ILD) were uniquely enriched. Conversely, Faecalibacterium prausnitzii, Bacteroides spp., and Roseburia inulinivorans showed depletion in both patient groups. Mycobiome analysis revealed depletion of certain fungi, including Saccharomyces cerevisiae and Candida albicans, in patients with RA compared with healthy subjects. Notably, gut virome alterations were characterized by an increase in Siphoviridae and a decrease in Myoviridae, Microviridae, and Autographiviridae in both patient groups. Hence, multikingdom gut microbial signatures showed promise as diagnostic indicators for both RA-ILD and RA-non-ILD. Overall, this study provides comprehensive insights into the fecal virome, bacteriome, and mycobiome landscapes of RA-ILD and RA-non-ILD gut microbiota, thereby offering potential biomarkers for further mechanistic and clinical research.

The impact of high-salt diet on asthma in humans and mice: Effect on specific T-cell signatures and microbiome

BACKGROUND

The rise in asthma has been linked to different environmental and lifestyle factors including dietary habits. Whether dietary salt contributes to asthma incidence, remains controversial. We aimed to investigate the impact of higher salt intake on asthma incidence in humans and to evaluate underlying mechanisms using mouse models.

METHODS

Epidemiological research was conducted using the UK Biobank Resource. Data were obtained from 42,976 participants with a history of allergies. 24-h sodium excretion was estimated from spot urine, and its association with asthma incidence was assessed by Cox regression, adjusting for relevant covariates. For mechanistic studies, a mouse model of mite-induced allergic airway inflammation (AAI) fed with high-salt diet (HSD) or normal-salt chow was used to characterize disease development. The microbiome of lung and feces (as proxy for gut) was analyzed via 16S rRNA gene based metabarcoding approach.

RESULTS

In humans, urinary sodium excretion was directly associated with asthma incidence among females but not among males. HSD-fed female mice displayed an aggravated AAI characterized by increased levels of total IgE, a TH2-TH17-biased inflammatory cell infiltration accompanied by upregulation of osmosensitive stress genes. HSD induced distinct changes in serum short chain fatty acids and in both gut and lung microbiome, with a lower Bacteroidetes to Firmicutes ratio and decreased Lactobacillus relative abundance in the gut, and enriched members of Gammaproteobacteria in the lung.

CONCLUSIONS

High dietary salt consumption correlates with asthma incidence in female adults with a history of allergies. Female mice revealed HSD-induced T-cell lung profiles accompanied by alterations of gut and lung microbiome.

A synbiotic mixture of Bifidobacterium breve M16-V, oligosaccharides and pectin, enhances Short Chain Fatty Acid production and improves lung health in a preclinical model for pulmonary neutrophilia

Introduction

Pulmonary neutrophilia is a hallmark of numerous airway diseases including Chronic Obstructive Pulmonary Disease (COPD), Neutrophilic asthma, Acute Lung Injury (ALI), Acute Respiratory Distress Syndrome (ARDS) and COVID-19. The aim of the current study was to investigate the effect of dietary interventions on lung health in context of pulmonary neutrophilia.

Methods

Male BALB/cByJ mice received 7 intra-nasal doses of either a vehicle or lipopolysaccharides (LPS). To study the effect of nutritional interventions they received 16 intra-gastric doses of either a vehicle (PBS) or the following supplements (1) probiotic Bifidobacterium breve (B. breve) M16-V; (2) a prebiotic fiber mixture of short-chain galacto-oligosaccharides, long-chain fructo-oligosaccharides, and low-viscosity pectin in a 9:1:2 ratio (scGOS/lcFOS/lvPectin); and (3) A synbiotic combination B. breve M16-V and scGOS/lcFOS/lvPectin. Parameters for lung health included lung function, lung morphology and lung inflammation. Parameters for systemic immunomodulation included levels of fecal short chain fatty acids and regulatory T cells.

Results

The synbiotic supplement protected against the LPS induced decline in lung function (35% improved lung resistance at baseline p = 0.0002 and 25% at peak challenge, p = 0.0002), provided a significant relief from pulmonary neutrophilia (40.7% less neutrophils, p < 0.01) and improved the pulmonary neutrophil-to-lymphocyte ratio (NLR) by 55.3% (p = 0.0033). Supplements did not impact lung morphology in this specific experiment. LPS applied to the upper airways induced less fecal SCFAs production compared to mice that received PBS. The production of acetic acid between day -5 and day 16 was increased in all unchallenged mice (PBS-PBS p = 0.0003; PBS-Pro p < 0.0001; PBS-Pre, p = 0.0045; PBS-Syn, p = 0.0005) which upon LPS challenge was only observed in mice that received the synbiotic mixture of B. breve M16-V and GOS:FOS:lvPectin (p = 0.0003). A moderate correlation was found for butyric acid and lung function parameters and a weak correlation was found between acetic acid, butyric acid and propionic acid concentrations and NLR.

Conclusion

This study suggests bidirectional gut lung cross-talk in a mouse model for pulmonary neutrophilia. Neutrophilic lung inflammation coexisted with attenuated levels of fecal SCFA. The beneficial effects of the synbiotic mixture of B. breve M16-V and GOS:FOS:lvPectin on lung health associated with enhanced levels of SCFAs.

Modulating the gut microbiome in non-small cell lung cancer: Challenges and opportunities

Despite the efficacy of immunotherapy in non-small cell lung cancer (NSCLC), the majority of the patients experience relapse with limited subsequent treatment options. Preclinical studies of various epithelial tumors, such as melanoma and NSCLC, have shown that harnessing the gut microbiome resulted in improvement of therapeutic responses to immunotherapy. Is this review, we summarize the role of microbiome, including lung and gut microbiome in the context of NSCLC, provide overview of the mechanisms of microbiome in efficacy and toxicity of chemotherapies and immunotherapies, and address current ongoing clinical trials for NSCLC including fecal microbiota transplantation (FMT) and live biotherapeutic products (LBPs).

Pulmonary comorbidities in people with HIV- the microbiome connection

PURPOSE OF REVIEW

To report recent evidence on associations between human microbiome, particularly airway and gut, and pulmonary comorbidities in people with HIV (PWH). Furthermore, we explore how changes in the microbiome may contribute to pulmonary immune dysregulation and higher rates of pulmonary comorbidities among PWH. Finally, we propose future directions in the field.

RECENT FINDINGS

Increased risk of pulmonary comorbidities and rapid lung function decline have been reported in even well treated PWH. Altered microbiota profiles have been reported in PWH with pulmonary comorbidities and rapid lung function decline as compared to those without. The most consistent data have been the association between HIV-related pulmonary comorbidities, lung and oral microbiota dysbiosis, which has been also associated with distinct respiratory mucosal inflammatory profiles and short-term mortality. However, a possible causal link remains to be elucidated.

SUMMARY

Associations between the lung and oral microbiome, HIV-associated pulmonary comorbidities and rapid lung function decline have been reported in recent studies. Yet the underlying mechanism underpinning the observed associations is largely unknown and substantial knowledge gaps remain. Future research is warranted to unveil the role and mechanism of human microbiome from different anatomical compartments in relation to pulmonary comorbidities in PWH.

The hidden link: How oral and respiratory microbiomes affect multiple sclerosis

BACKGROUND

Extensive research has explored the role of gut microbiota in multiple sclerosis (MS). However, the impact of microbial communities in the oral cavity and respiratory tract on MS is an emerging area of investigation.

PURPOSE

We aimed to review the current literature related to the nasal, oral, and lung microbiota in people with MS (PwMS).

METHODS

We conducted a narrative review of clinical and preclinical original studies on PubMed that explored the relationship between the bacterial or viral composition of the nasal, lung, and oral microbiota and MS. Additionally, to find relevant studies not retrieved initially, we also searched for references in related review papers, as well as the references cited within the included studies.

RESULTS AND CONCLUSIONS

Thirteen studies were meticulously reviewed in three sections; oral microbiota (n = 8), nasal microbiota (n = 3), and lung microbiota (n = 2), highlighting considerable alterations in the oral and respiratory microbiome of PwMS compared to healthy controls (HCs). Genera like Aggregatibacter and Streptococcus were less abundant in the oral microbiota of PwMS compared to HCs, while Staphylococcus, Leptotrichia, Fusobacterium, and Bacteroides showed increased abundance in PwMS. Additionally, the presence of specific bacteria, including Streptococcus sanguinis, within the oral microbiota was suggested to influence Epstein-Barr virus reactivation, a well-established risk factor for MS. Studies related to the nasal microbiome indicated elevated levels of specific Staphylococcus aureus toxins, as well as nasal glial cell infection with human herpes virus (HHV)-6 in PwMS. Emerging research on lung microbiome in animal models demonstrated that manipulating the lung microbiome towards lipopolysaccharide-producing bacteria might suppress MS symptoms. These findings open avenues for potential therapeutic strategies. However, further research is crucial to fully understand the complex interactions between the microbiome and MS. This will help identify the most effective timing, bacterial strains, and modulation techniques.

Cross-domain microbiomes: the interaction of gut, lung and environmental microbiota in asthma pathogenesis

Recent experimental and epidemiological studies underscore the vital interaction between the intestinal microbiota and the lungs, an interplay known as the "gut-lung axis". The significance of this axis has been further illuminated following the identification of intestinal microbial metabolites, such as short-chain fatty acids (SCFA), as key mediators in setting the tone of the immune system. Through the gut-lung axis, the gut microbiota and its metabolites, or allergens, are directly or indirectly involved in the immunomodulation of pulmonary diseases, thereby increasing susceptibility to allergic airway diseases such as asthma. Asthma is a complex outcome of the interplay between environmental factors and genetic predispositions. The concept of the gut-lung axis may offer new targets for the prevention and treatment of asthma. This review outlines the relationships between asthma and the respiratory microbiome, gut microbiome, and environmental microbiome. It also discusses the current advancements and applications of microbiomics, offering novel perspectives and strategies for the clinical management of chronic respiratory diseases like asthma.

Comorbid functional dyspepsia reflects IL-33-mediated airway neuronal dysfunction in asthma

BACKGROUND

Neuronal dysfunction is implicated in the pathophysiology of asthma and functional dyspepsia (FD). However, the relationship between these diseases remains unclear.

OBJECTIVE

This study aimed to clarify the clinical implications of comorbid FD in asthma and to explore the unified pathway between asthma and FD by focusing on airway neuronal dysfunction.

METHODS

Clinical indices and biomarkers, including capsaicin cough sensitivity (C-CS), were compared between patients with asthma with and without FD. C-CS was determined on the basis of capsaicin concentration that induced at least 2 coughs (C2) or 5 coughs (C5). Additionally, the associations of airway inflammation with airway innervation and gastrointestinal motility were evaluated in mouse models of type 2 airway inflammation.

RESULTS

Patients with asthma with FD had worse asthma control and cough severity and lower C2 and C5 thresholds than those without FD. The severity of FD symptoms was negatively correlated with C2 and C5 thresholds. FD and poor asthma control were predictors of heightened C-CS (defined as C5 ≤ 2.44 μmol) in asthma. A mouse model of papain-induced airway inflammation developed airway hyperinnervation and gastrointestinal dysmotility, and both pathologies were ameliorated by an anti-IL-33 antibody. Moreover, papain-induced gastrointestinal dysmotility was mitigated by silencing the airway sensory neurons using QX-314, a sodium channel blocker. Furthermore, sputum IL-33 levels were significantly elevated in patients with asthma with FD or heightened C-CS compared to their counterparts.

CONCLUSION

FD is significantly associated with airway neuronal dysfunction in asthma. IL-33-mediated airway neuronal dysfunction may contribute to the interaction between asthma and FD.

Comprehensive analysis of the gut microbiota in patients with chronic obstructive pulmonary disease of varying severity-A prospective, observational study

Accumulating evidence has highlighted the influence of the gut microbiota on lung immunity. We examined the effects of changes in intestinal microecology on the development of Chronic Obstructive Pulmonary Disease (COPD) and identified microbial biomarkers for acute exacerbations of COPD (AECOPD). Fecal samples were collected from 30 patients with stable COPD, 30 patients with AECOPD, and 10 healthy individuals. Fecal microbiological profiles were analyzed using 16S rRNA gene sequencing. The results showed a distinct difference in the bacterial community composition between the AECOPD, COPD, and healthy control groups. The COPD and AECOPD groups had higher levels of Firmicutes but lower levels of Bacteroidetes compared to the healthy control group at the phylum level. At the genus level, there was an increased abundance of Lachnoclostridium, Alistipes, Streptococcus, and Prevotella in COPD and AECOPD patients. Increasing levels of Lachnoclostridium and Prevotella may indicate an acute exacerbation of COPD. This study identified specific microbial biomarkers associated with AECOPD and characterized the composition of gut microbiota in patients with AECOPD.

Gut microbiota-derived acetate attenuates lung injury induced by influenza infection via protecting airway tight junctions

BACKGROUND

Gut microbiota (GM) have been implicated as important regulators of gastrointestinal symptom which is commonly occurred along with respiratory influenza A virus (IAV) infection, suggesting the involvement of the gut-to-lung axis in a host's response to IAV. IAV primarily destroys airway epithelium tight junctions (TJs) and consequently causes acute respiratory disease syndrome. It is known that GM and their metabolism produce an anti-influenza effect, but their role in IAV-induced airway epithelial integrity remains unknown.

METHODS

A mouse model of IAV infection was established. GM were analyzed using 16S rRNA gene sequencing, and short-chain fatty acids (SCFAs) levels were measured. GM depletion and fecal microbiota transplantation (FMT) were conducted to validate the role of GM in IAV infection. A pair-feeding experiment was conducted to reveal whether IAV-induced GM dysbiosis is attributed to impaired food intake. Furthermore, human bronchial epithelial (HBE) cells were cocultured with IAV in the presence or absence of acetate. TJs function was analyzed by paracellular permeability and transepithelial electronic resistance (TEER). The mechanism of how acetate affects TJs integrity was evaluated in HBE cells transfected with G protein-coupled receptor 43 (GPR43) short hairpin RNA (shRNA).

RESULTS

IAV-infected mice exhibited lower relative abundance of acetate-producing bacteria (Bacteroides, Bifidobacterium, and Akkermansia) and decreased acetate levels in gut and serum. These changes were partly caused by a decrease in food consumption (due to anorexia). GM depletion exacerbated and FMT restored IAV-induced lung inflammatory injury. IAV infection suppressed expressions of TJs (occludin, ZO-1) leading to disrupted airway epithelial barrier function as evidenced by decreased TEER and increased permeability. Acetate pretreatment activated GPR43, partially restored IAV-induced airway epithelial barrier function, and reduced inflammatory cytokines levels (TNF-α, IL-6, and IL-1β). Such protective effects of acetate were absent in HBE cells transfected with GPR43 shRNA. Acetate and GPR43 improved TJs in an AMP-activated protein kinase (AMPK)-dependent manner.

CONCLUSION

Collectively, our results demonstrated that GM protected airway TJs by modulating GPR43-AMPK signaling in IAV-induced lung injury. Therefore, improving GM dysbiosis may be a potential therapeutic target for patients with IAV infection.

Gut microbiota as a sensor of autoimmune response and treatment for rheumatoid arthritis

Rheumatoid arthritis (RA) is considered a multifactorial condition where interaction between the genetic and environmental factors lead to immune dysregulation causing autoreactivity. While among the various genetic factors, HLA-DR4 and DQ8, have been reported to be the strongest risk factors, the role of various environmental factors has been unclear. Though events initiating autoreactivity remain unknown, a mucosal origin of RA has gained attention based on the recent observations with the gut dysbiosis in patients. However, causality of gut dysbiosis has been difficult to prove in humans. Mouse models, especially mice expressing RA-susceptible and -resistant HLA class II genes have helped unravel the complex interactions between genetic factors and gut microbiome. This review describes the interactions between HLA genes and gut dysbiosis in sex-biased preclinical autoreactivity and discusses the potential use of endogenous commensals as indicators of treatment efficacy as well as therapeutic tool to suppress pro-inflammatory response in rheumatoid arthritis.

Identification of Causal Relationships between Gut Microbiota and Influenza a Virus Infection in Chinese by Mendelian Randomization

Numerous studies have reported a correlation between gut microbiota and influenza A virus (IAV) infection and disease severity. However, the causal relationship between these factors remains inadequately explored. This investigation aimed to assess the influence of gut microbiota on susceptibility to human infection with H7N9 avian IAV and the severity of influenza A (H1N1)pdm09 infection. A two-sample Mendelian randomization analysis was conducted, integrating our in-house genome-wide association study (GWAS) on H7N9 susceptibility and H1N1pdm09 severity with a metagenomics GWAS dataset from a Chinese population. Twelve and fifteen gut microbiotas were causally associated with H7N9 susceptibility or H1N1pdm09 severity, separately. Notably, Clostridium hylemonae and Faecalibacterium prausnitzii were negative associated with H7N9 susceptibility and H1N1pdm09 severity, respectively. Moreover, Streptococcus peroris and Streptococcus sanguinis were associated with H7N9 susceptibility, while Streptococcus parasanguini and Streptococcus suis were correlated with H1N1pdm09 severity. These results provide novel insights into the interplay between gut microbiota and IAV pathogenesis as well as new clues for mechanism research regarding therapeutic interventions or IAV infections. Future studies should concentrate on clarifying the regulatory mechanisms of gut microbiota and developing efficacious approaches to reduce the incidence of IAV infections, which could improve strategy for preventing and treating IAV infection worldwide.

Integrated analysis of microbiome and host transcriptome unveils correlations between lung microbiota and host immunity in bronchoalveolar lavage fluid of pneumocystis pneumonia patients

OBJECTIVE

The lung microbiota of patients with pulmonary diseases is disrupted and impacts the immunity. The microbiological and immune landscape of the lungs in patients with pneumocystis pneumonia (PCP) remains poorly understood.

METHODS

Multi-omics analysis and machine learning were performed on bronchoalveolar lavage fluid to explore interaction between the lung microbiota and host immunity in PCP. Then we constructed a diagnostic model using differential genes with LASSO regression and validated by qPCR. The immune infiltration analysis was performed to explore the landscape of lung immunity in patients with PCP.

RESULTS

Patients with PCP showed a low alpha diversity of lung microbiota, accompanied by the elevated abundance of Firmicutes, and the differential expressed genes (DEGs) analysis displayed a downregulation of MAPK signaling. The MAPK10, TGFB1, and EFNA3 indicated a potential to predict PCP (AUC = 0.86). The lung immune landscape in PCP showed the lower levels of naïve CD4+ T cells and activated dendritic cells. The correlation analysis of the MAPK signaling pathway-related DEGs and the differential microorganisms at the level of phylum showed that the Firmicutes was negatively correlated with these DEGs.

CONCLUSION

We profiled the characteristics of lung microbiota and immune landscape in PCP, which may contribute to elucidating the mechanism of PCP.

Gut microbes improve prognosis of Klebsiella pneumoniae pulmonary infection through the lung-gut axis

Background

The gut microbiota plays a vital role in the development of sepsis and in protecting against pneumonia. Previous studies have demonstrated the existence of the gut-lung axis and the interaction between the gut and the lung, which is related to the prognosis of critically ill patients; however, most of these studies focused on chronic lung diseases and influenza virus infections. The purpose of this study was to investigate the effect of faecal microbiota transplantation (FMT) on Klebsiella pneumoniae-related pulmonary infection via the gut-lung axis and to compare the effects of FMT with those of traditional antibiotics to identify new therapeutic strategies.

Methods

We divided the mice into six groups: the blank control (PBS), pneumonia-derived sepsis (KP), pneumonia-derived sepsis + antibiotic (KP + PIP), pneumonia-derived sepsis + faecal microbiota transplantation(KP + FMT), antibiotic treatment control (KP+PIP+PBS), and pneumonia-derived sepsis+ antibiotic + faecal microbiota transplantation (KP + PIP + FMT) groups to compare the survival of mice, lung injury, inflammation response, airway barrier function and the intestinal flora, metabolites and drug resistance genes in each group.

Results

Alterations in specific intestinal flora can occur in the gut of patients with pneumonia-derived sepsis caused by Klebsiella pneumoniae. Compared with those in the faecal microbiota transplantation group, the antibiotic treatment group had lower levels of proinflammatory factors and higher levels of anti-inflammatory factors but less amelioration of lung pathology and improvement of airway epithelial barrier function. Additionally, the increase in opportunistic pathogens and drug resistance-related genes in the gut of mice was accompanied by decreased production of favourable fatty acids such as acetic acid, propionic acid, butyric acid, decanoic acid, and secondary bile acids such as chenodeoxycholic acid 3-sulfate, isodeoxycholic acid, taurodeoxycholic acid, and 3-dehydrocholic acid; the levels of these metabolites were restored by faecal microbiota transplantation. Faecal microbiota transplantation after antibiotic treatment can gradually ameliorate gut microbiota disorder caused by antibiotic treatment and reduce the number of drug resistance genes induced by antibiotics.

Conclusion

In contrast to direct antibiotic treatment, faecal microbiota transplantation improves the prognosis of mice with pneumonia-derived sepsis caused by Klebsiella pneumoniae by improving the structure of the intestinal flora and increasing the level of beneficial metabolites, fatty acids and secondary bile acids, thereby reducing systemic inflammation, repairing the barrier function of alveolar epithelial cells, and alleviating pathological damage to the lungs. The combination of antibiotics with faecal microbiota transplantation significantly alleviates intestinal microbiota disorder, reduces the selection for drug resistance genes caused by antibiotics, and mitigates lung lesions; these effects are superior to those following antibiotic monotherapy.

The Role of Biodiversity in the Development of Asthma and Allergic Sensitization: A State-of-the-Science Review

BACKGROUND

Changes in land use and climate change have been reported to reduce biodiversity of both the environment and human microbiota. These reductions in biodiversity may lead to inadequate and unbalanced stimulation of immunoregulatory circuits and, ultimately, to clinical diseases, such as asthma and allergies.

OBJECTIVE

We summarized available empirical evidence on the role of inner (gut, skin, and airways) and outer (air, soil, natural waters, plants, and animals) layers of biodiversity in the development of asthma, wheezing, and allergic sensitization.

METHODS

We conducted a systematic search in SciVerse Scopus, PubMed MEDLINE, and Web of Science up to 5 March 2024 to identify relevant human studies assessing the relationships between inner and outer layers of biodiversity and the risk of asthma, wheezing, or allergic sensitization. The protocol was registered in PROSPERO (CRD42022381725).

RESULTS

A total of 2,419 studies were screened and, after exclusions and a full-text review of 447 studies, 82 studies were included in the comprehensive, final review. Twenty-nine studies reported a protective effect of outer layer biodiversity in the development of asthma, wheezing, or allergic sensitization. There were also 16 studies suggesting an effect of outer layer biodiversity on increasing asthma, wheezing, or allergic sensitization. However, there was no clear evidence on the role of inner layer biodiversity in the development of asthma, wheezing, and allergic sensitization (13 studies reported a protective effect and 15 reported evidence of an increased risk).

CONCLUSIONS

Based on the reviewed literature, a future systematic review could focus more specifically on outer layer biodiversity and asthma. It is unlikely that association with inner layer biodiversity would have enough evidence for systematic review. Based on this comprehensive review, there is a need for population-based longitudinal studies to identify critical periods of exposure in the life course into adulthood and to better understand mechanisms linking environmental exposures and changes in microbiome composition, diversity, and/or function to development of asthma and allergic sensitization. https://doi.org/10.1289/EHP13948.

Exploring immune-related pathogenesis in lung injury: Providing new insights Into ALI/ARDS

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) represent a significant global burden of morbidity and mortality, with lung injury being the primary cause of death in affected patients. The pathogenesis of lung injury, however, remains a complex issue. In recent years, the role of the immune system in lung injury has attracted extensive attention worldwide. Despite advancements in our understanding of various lung injury subtypes, significant limitations persist in both prevention and treatment. This review investigates the immunopathogenesis of ALI/ARDS, aiming to elucidate the pathological processes of lung injury mediated by dendritic cells (DCs), natural killer (NK) cells, phagocytes, and neutrophils. Furthermore, the article expounds on the critical contributions of gut microbiota, inflammatory pathways, and cytokine storms in the development of ALI/ARDS.

Exploring the lung-gut direction of the gut-lung axis in patients with ARDS

Acute respiratory distress syndrome (ARDS) represents a life-threatening inflammatory reaction marked by refractory hypoxaemia and pulmonary oedema. Despite advancements in treatment perspectives, ARDS still carries a high mortality rate, often due to systemic inflammatory responses leading to multiple organ dysfunction syndrome (MODS). Indeed, the deterioration and associated mortality in patients with acute lung injury (LI)/ARDS is believed to originate alongside respiratory failure mainly from the involvement of extrapulmonary organs, a consequence of the complex interaction between initial inflammatory cascades related to the primary event and ongoing mechanical ventilation-induced injury resulting in multiple organ failure (MOF) and potentially death. Even though recent research has increasingly highlighted the role of the gastrointestinal tract in this process, the pathophysiology of gut dysfunction in patients with ARDS remains mainly underexplored. This review aims to elucidate the complex interplay between lung and gut in patients with LI/ARDS. We will examine various factors, including systemic inflammation, epithelial barrier dysfunction, the effects of mechanical ventilation (MV), hypercapnia, and gut dysbiosis. Understanding these factors and their interaction may provide valuable insights into the pathophysiology of ARDS and potential therapeutic strategies to improve patient outcomes.

Genetic associations between gut microbiota and allergic rhinitis: an LDSC and MR analysis

Background

Several studies have suggested a potential link between allergic rhinitis (AR) and gut microbiota. In response, we conducted a meta-analysis of Linkage Disequilibrium Score Regression (LDSC) and Mendelian randomization (MR) to detect their genetic associations.

Methods

Summary statistics for 211 gut microbiota taxa were gathered from the MiBioGen study, while data for AR were sourced from the Pan-UKB, the FinnGen, and the Genetic Epidemiology Research on Aging (GERA). The genetic correlation between gut microbiota and AR was assessed using LDSC. The principal estimate of causality was determined using the Inverse-Variance Weighted (IVW) method. To assess the robustness of these findings, sensitivity analyses were conducted employing methods such as the weighted median, MR-Egger, and MR-PRESSO. The summary effect estimates of LDSC, forward MR and reverse MR were combined using meta-analysis for AR from different data resources.

Results

Our study indicated a significant genetic correlation between genus Sellimonas (Rg = -0.64, p = 3.64 × 10-5, Adjust_P = 3.64 × 10-5) and AR, and a suggestive genetic correlation between seven bacterial taxa and AR. Moreover, the forward MR analysis identified genus Gordonibacter, genus Coprococcus2, genus LachnospiraceaeUCG010, genus Methanobrevibacter, and family Victivallaceae as being suggestively associated with an increased risk of AR. The reverse MR analysis indicated that AR was suggestively linked to an increased risk for genus Coprococcus2 and genus RuminococcaceaeUCG011.

Conclusion

Our findings indicate a causal relationship between specific gut microbiomes and AR. This enhances our understanding of the gut microbiota's contribution to the pathophysiology of AR and lays the groundwork for innovative approaches and theoretical models for future prevention and treatment strategies in this patient population.

A Narrative Review on Gut Microbiome Disturbances and Microbial Preparations in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Implications for Long COVID

Myalgic encephalomyelitis, also known as chronic fatigue syndrome (ME/CFS), and long COVID are complex, multisystemic and long-term disabling conditions characterized by debilitating post-exertional malaise and other core symptoms related to immune dysregulation resultant from post-viral infection, including mitochondrial dysfunction, chronic neuroinflammation and gut dysbiosis. The reported associations between altered microbiota composition and cardinal symptoms of ME/CFS and long COVID suggest that the use of microbial preparations, such as probiotics, by restoring the homeostasis of the brain-immune-gut axis, may help in the management of symptoms in both conditions. Therefore, this review aims to investigate the implications of alerted gut microbiome and assess the evidence supporting use of microbial-based preparations, including probiotics, synbiotics, postbiotics alone and/or in combination with other nutraceuticals in the management of fatigue, inflammation and neuropsychiatric and gastrointestinal symptoms among patients with ME/CFS and long COVID.

Does "all disease begin in the gut"? The gut-organ cross talk in the microbiome

The human microbiome, a diverse ecosystem of microorganisms within the body, plays pivotal roles in health and disease. This review explores site-specific microbiomes, their role in maintaining health, and strategies for their upkeep, focusing on oral, lung, vaginal, skin, and gut microbiota, and their systemic connections. Understanding the intricate relationships between these microbial communities is crucial for unraveling mechanisms underlying human health. Recent research highlights bidirectional communication between the gut and distant microbiome sites, influencing immune function, metabolism, and disease susceptibility. Alterations in one microbiome can impact others, emphasizing their interconnectedness and collective influence on human physiology. The therapeutic potential of gut microbiota in modulating distant microbiomes offers promising avenues for interventions targeting various disorders. Through interdisciplinary collaboration and technological advancements, we can harness the power of the microbiome to revolutionize healthcare, emphasizing microbiome-centric approaches to promote holistic well-being while identifying areas for future research.

Involvement of GPR43 Receptor in Effect of Lacticaseibacillus rhamnosus on Murine Steroid Resistant Chronic Obstructive Pulmonary Disease: Relevance to Pro-Inflammatory Mediators and Oxidative Stress in Human Macrophages

BACKGROUND

Cytokine storm and oxidative stress are present in chronic obstructive pulmonary disease (COPD). Individuals with COPD present high levels of NF-κB-associated cytokines and pro-oxidant agents as well as low levels of Nrf2-associated antioxidants. This condition creates a steroid-resistant inflammatory microenvironment. Lacticaseibacillus rhamnosus (Lr) is a known anti-cytokine in lung diseases; however, the effect of Lr on lung inflammation and oxidative stress in steroid-resistant COPD mice remains unknown.

OBJECTIVE

Thus, we investigated the Lr effect on lung inflammation and oxidative stress in mice and macrophages exposed to cigarette smoke extract (CSE) and unresponsive to steroids.

METHODS

Mice and macrophages received dexamethasone or GLPG-094 (a GPR43 inhibitor), and only the macrophages received butyrate (but), all treatments being given before CSE. Lung inflammation was evaluated from the leukocyte population, airway remodeling, cytokines, and NF-κB. Oxidative stress disturbance was measured from ROS, 8-isoprostane, NADPH oxidase, TBARS, SOD, catalase, HO-1, and Nrf2.

RESULTS

Lr attenuated cellularity, mucus, collagen, cytokines, ROS, 8-isoprostane, NADPH oxidase, and TBARS. Otherwise, SOD, catalase, HO-1, and Nrf2 were upregulated in Lr-treated COPD mice. Anti-cytokine and antioxidant effects of butyrate also occurred in CSE-exposed macrophages. GLPG-094 rendered Lr and butyrate less effective.

CONCLUSIONS

Lr attenuates lung inflammation and oxidative stress in COPD mice, suggesting the presence of a GPR43 receptor-dependent mechanism also found in macrophages.

Lung-Gut Microbiota and Tryptophan Metabolites Changes in Neonatal Acute Respiratory Distress Syndrome

Purpose

Neonatal Acute Respiratory Distress Syndrome (NARDS) is a severe respiratory crisis threatening neonatal life. We aim to identify changes in the lung-gut microbiota and lung-plasma tryptophan metabolites in NARDS neonates to provide a differentiated tool and aid in finding potential therapeutic targets.

Patients and Methods

Lower respiratory secretions, faeces and plasma were collected from 50 neonates including 25 NARDS patients (10 patients with mild NARDS in the NARDS_M group and 15 patients with moderate-to-severe NARDS in the NARDS_S group) and 25 control patients screened based on gestational age, postnatal age and birth weight. Lower airway secretions and feces underwent 16S rRNA gene sequencing to understand the microbial communities in the lung and gut, while lower airway secretions and plasma underwent LC-MS analysis to understand tryptophan metabolites in the lung and blood. Correlation analyses were performed by comparing differences in microbiota and tryptophan metabolites between NARDS and control, NARDS_S and NARDS_M groups.

Results

Significant changes in lung and gut microbiota as well as lung and plasma tryptophan metabolites were observed in NARDS neonates compared to controls. Proteobacteria and Bacteroidota were increased in the lungs of NARDS neonates, whereas Firmicutes, Streptococcus, and Rothia were reduced. Lactobacillus in the lungs decreased in NARDS_S neonates. Indole-3-carboxaldehyde decreased in the lungs of NARDS neonates, whereas levels of 3-hydroxykynurenine, indoleacetic acid, indolelactic acid, 3-indole propionic acid, indoxyl sulfate, kynurenine, and tryptophan decreased in the lungs of the NARDS_S neonates. Altered microbiota was significantly related to tryptophan metabolites, with changes in lung microbiota and tryptophan metabolites having better differentiated ability for NARDS diagnosis and grading compared to gut and plasma.

Conclusion

Significant changes occurred in the lung-gut microbiota and lung-plasma tryptophan metabolites of NARDS neonates. Alterations in lung microbiota and tryptophan metabolites were better discriminatory for the diagnosis and grading of NARDS.

Alteration of the gut microbiota in patients with lung cancer accompanied by chronic obstructive pulmonary diseases

Aim

To explore the abundance and diversity of the gut microbiota in patients with lung cancer accompanied by chronic obstructive pulmonary disease (LC-COPD).

Methods

The study cohort comprised 15 patients with LC-COPD, 49 patients with lung cancer, and 18 healthy control individuals. ELISA was used to detect inflammatory factors in venous blood. 16S rDNA sequencing was performed to determine the abundance and diversity of the gut microbiota. Gas chromatography-mass spectrometry was used to determine the concentration of short-chain fatty acids (SCFAs) in feces samples.

Results

The α-diversity index indicated that the richness and diversity of the gut microbiota were lower in patients with LC-COPD compared with patients with lung cancer and controls. Principal component analysis revealed significant differences among the three groups (P < 0.05). The linear discriminant analysis effect size algorithm indicated that the o_Lactobacillales, g_Lactobaccillus, f_Lactobaccillaceae, s_Lactobaccillus_oris, c_Bacilli, g_Anaerofustis, s_uncultured organism, and s_bacterium_P1C10 species were prevalent in patients with LC-COPD, while the g_Clostridium_XIVa and g_Butyricicoccus species were prevalent in patients with lung cancer. Furthermore, the concentrations of the SCFAs butyric acid, isobutyric acid, isovaleric acid, and valeric acid tended to be lower in patients with LC-COPD compared with patients with lung cancer and healthy controls, although these intergroup differences were not significant (P > 0.05). Patients with lung cancer had the lowest serum concentration of tumor necrosis factor (TNF)-a. There were no intergroup differences in the concentrations of other inflammatory factors.

Conclusions

The present study indicated that the abundance and structure of the gut microbiota is altered, and the concentrations of SCFAs may be decreased in patients with LC-COPD. In addition, patients with lung cancer had the lowest serum concentration of TNF-a.

Relationship between dietary live microbe intake and the prevalence of COPD in adults: a cross-sectional study of NHANES 2013-2018

OBJECTIVE

To explore the potential association between dietary live microbes and the prevalence of Chronic Obstructive Pulmonary Diseases (COPD).

METHODS

In this cross-sectional study, data of 9791 participants aged 20 years or older in this study were collected from the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2018. Participants in this study were classified into three groups according to the Sanders' dietary live microbe classification system: low, medium, and high dietary live microbe groups. COPD was defined by a combination of self-reported physician diagnoses and standardized medical status questionnaires. Logistic regression and subgroup analysis were used to assess whether dietary live microbes were associated with the risk of COPD.

RESULTS

Through full adjustment for confounders, participants in the high dietary live microbe group had a low prevalence of COPD in contrast to those in low dietary live microbe group (OR: 0.614, 95% CI: 0.474-0.795, and p < 0.001), but no significant association with COPD was detected in the medium and the low dietary live microbe groups. This inverse relationship between dietary live microbe intake and COPD prevalence was more inclined to occur in smokers, females, participants aged from 40 to 59 years old and non-obese participants.

CONCLUSION

A high dietary live microbe intake was associated with a low prevalence of COPD, and this negative correlation was detected especially in smokers, females, participants aged from 40 to 59 years old and non-obese participants.

Exploring the complexities of poultry respiratory microbiota: colonization, composition, and impact on health

An accurate understanding of the ecology and complexity of the poultry respiratory microbiota is of utmost importance for elucidating the roles of commensal or pathogenic microorganisms in the respiratory tract, as well as their associations with health or disease outcomes in poultry. This comprehensive review delves into the intricate aspects of the poultry respiratory microbiota, focusing on its colonization patterns, composition, and impact on poultry health. Firstly, an updated overview of the current knowledge concerning the composition of the microbiota in the respiratory tract of poultry is provided, as well as the factors that influence the dynamics of community structure and diversity. Additionally, the significant role that the poultry respiratory microbiota plays in economically relevant respiratory pathobiologies that affect poultry is explored. In addition, the challenges encountered when studying the poultry respiratory microbiota are addressed, including the dynamic nature of microbial communities, site-specific variations, the need for standardized protocols, the appropriate sequencing technologies, and the limitations associated with sampling methodology. Furthermore, emerging evidence that suggests bidirectional communication between the gut and respiratory microbiota in poultry is described, where disturbances in one microbiota can impact the other. Understanding this intricate cross talk holds the potential to provide valuable insights for enhancing poultry health and disease control. It becomes evident that gaining a comprehensive understanding of the multifaceted roles of the poultry respiratory microbiota, as presented in this review, is crucial for optimizing poultry health management and improving overall outcomes in poultry production.

Immune cells mediated the causal relationship between the gut microbiota and lung cancer: a Mendelian randomization study

Introduction

The gut microbiota (GM) influences the occurrence and progression of lung cancer (LC), with potential involvement of immune cells (IC). We aimed to investigate the causal impact of GM on LC and identify potential immune cell mediators.

Methods

The utilized data for the Genome-Wide Association Studies (GWAS) were summarized as follows: gut microbiota data from the Dutch Microbiome Project (DMP) (N = 7,738), lung cancer data from the Transdisciplinary Research in Cancer of the Lung (TRICL) and International Lung Cancer Consortium (ILCCO) (Ncase = 29,266, Ncontrol = 56,450) included four types of cancer: NSCLC, LUAD, LUSC, and SCLC, and immune cell data from European populations (N = 3,757). We employed bi-directional two-sample univariable Mendelian randomization (UVMR), multivariable Mendelian randomization (MVMR), and mediation analysis to assess the causal relationship between GM and LC and potential immune cell mediators.

Results

Bi-directional UVMR analysis revealed that 24 gut microbiota species can affect LC, while LC can affect the abundance of 17 gut microbiota species. Mediation analysis demonstrated that six immune cells mediated the causal relationships of seven gut microbiota species on LC: "CCR7 on naive CD8+ T cell" mediated the causal relationship between s_Alistipes_putredinis and LUAD, with a mediation proportion of 9.5% and P = 0.018; "IgD- CD27- B cell %lymphocyte" mediated the causal relationships between g_Gordonibacter and s_Gordonibacter_pamelaeae with LUSC, with mediation proportions of 11.8% and 11.9%, respectively and P = 0.029; "CD20- CD38- B cell %lymphocyte" mediated the causal relationship between s_Bacteroides_clarus and SCLC, with a mediation proportion of 13.8% and P = 0.005; "CD20 on IgD+ CD38- unswitched memory B cell" mediated the causal relationship between s_Streptococcus_thermophilus and SCLC, with a mediation proportion of 14.1% and P = 0.023; "HLA DR on CD14- CD16+ monocyte" mediated the causal relationship between s_Bifidobacterium_bifidum and SCLC, with a mediation proportion of 8.7% and P = 0.012; "CD45 on Granulocytic Myeloid-Derived Suppressor Cells" mediated the causal relationship between f_Lactobacillaceae and SCLC, with a mediation proportion of 4.0% and P = 0.021.

Conclusion

This Mendelian randomization study identified several specific gut microbiotas that exhibit causal relationships with lung cancer and potentially mediate immune cells.

Avian influenza and gut microbiome in poultry and humans: A "One Health" perspective

A gradual increase in avian influenza outbreaks has been found in recent years. It is highly possible to trigger the next human pandemic due to the characteristics of antigenic drift and antigenic shift in avian influenza virus (AIV). Although great improvements in understanding influenza viruses and the associated diseases have been unraveled, our knowledge of how these viruses impact the gut microbiome of both poultry and humans, as well as the underlying mechanisms, is still improving. The "One Health" approach shows better vitality in monitoring and mitigating the risk of avian influenza, which requires a multi-sectoral effort and highlights the interconnection of human health with environmental sustainability and animal health. Therefore, monitoring the gut microbiome may serve as a sentinel for protecting the common health of the environment, animals, and humans. This review summarizes the interactions between AIV infection and the gut microbiome of poultry and humans and their potential mechanisms. With the presented suggestions, we hope to address the current major challenges in the surveillance and prevention of microbiome-related avian influenza with the "One Health" approach.

Gut-lung axis and asthma: A historical review on mechanism and future perspective

BACKGROUND

Gut microbiota are closely related to the development and regulation of the host immune system by regulating the maturation of immune cells and the resistance to pathogens, which affects the host immunity. Early use of antibiotics disrupts the homeostasis of gut microbiota and increases the risk of asthma. Gut microbiota actively interact with the host immune system via the gut-lung axis, a bidirectional communication pathway between the gut and lung. The manipulation of gut microbiota through probiotics, helminth therapy, and fecal microbiota transplantation (FMT) to combat asthma has become a hot research topic. BODY: This review mainly describes the current immune pathogenesis of asthma, gut microbiota and the role of the gut-lung axis in asthma. Moreover, the potential of manipulating the gut microbiota and its metabolites as a treatment strategy for asthma has been discussed.

CONCLUSION

The gut-lung axis has a bidirectional effect on asthma. Gut microecology imbalance contributes to asthma through bacterial structural components and metabolites. Asthma, in turn, can also cause intestinal damage through inflammation throughout the body. The manipulation of gut microbiota through probiotics, helminth therapy, and FMT can inform the treatment strategies for asthma by regulating the maturation of immune cells and the resistance to pathogens.

Causal influence of gut microbiota on small cell lung cancer: a Mendelian randomization study

BACKGROUND

Previous studies have hinted at a significant link between lung cancer and the gut microbiome, yet their causal relationship remains to be elucidated.

METHODS

GWAS data for small cell lung cancer (SCLC) was extracted from the FinnGen consortium, comprising 179 cases and 218 613 controls. Genetic variation data for 211 gut microbiota were obtained as instrumental variables from MiBioGen. Mendelian randomization (MR) was employed to determine the causal relationship between the two, with inverse variance weighting (IVW) being the primary method for causal analysis. The MR results were validated through several sensitivity analyses.

RESULTS

The study identified a protective effect against SCLC for the genus Eubacterium ruminantium group (OR = 0.413, 95% CI: 0.223-0.767, p = 0.00513), genus Barnesiella (OR = 0.208, 95% CI: 0.0640-0.678, p = 0.00919), family Lachnospiraceae (OR = 0.319, 95% CI: 0.107-0.948, p = 0.03979), and genus Butyricimonas (OR = 0.376, 95% CI: 0.144-0.984, p = 0.04634). Conversely, genus Intestinibacter (OR = 3.214, 95% CI: 1.303-7.926, p = 0.01125), genus Eubacterium oxidoreducens group (OR = 3.391, 95% CI: 1.215-9.467, p = 0.01973), genus Bilophila (OR = 3.547, 95% CI: 1.106-11.371, p = 0.03315), and order Bacillales (OR = 1.860, 95% CI: 1.034-3.347, p = 0.03842) were found to potentially promote the onset of SCLC.

CONCLUSION

We identified potential causal relationships between certain gut microbiota and SCLC, offering new insights into microbiome-mediated mechanisms of SCLC pathogenesis, resistance, mutations, and more.

Inflammatory bowel disease and allergic diseases: A Mendelian randomization study

BACKGROUND

Inflammatory bowel disease (IBD) and allergic diseases possess similar genetic backgrounds and pathogenesis. Observational studies have shown a correlation, but the exact direction of cause and effect remains unclear. The aim of this Mendelian randomization (MR) study is to assess bidirectional causality between inflammatory bowel disease and allergic diseases.

METHOD

We comprehensively analyzed the causal relationship between inflammatory bowel disease (IBD), Crohn's disease (CD), ulcerative colitis (UC) and allergic disease (asthma, Hay fever, and eczema) as a whole, allergic conjunctivitis (AC), atopic dermatitis (AD), allergic asthma (AAS), and allergic rhinitis (AR) by performing a bidirectional Mendelian randomization study using summary-level data from genome-wide association studies. The analysis results mainly came from the random-effects model of inverse variance weighted (IVW-RE). In addition, multivariate Mendelian randomization (MVMR) analysis was conducted to adjust the effect of body mass index (BMI) on the instrumental variables.

RESULTS

The IVW-RE method revealed that IBD genetically increased the risk of allergic disease as a whole (OR = 1.03, 95% CI = 1.01-1.04, fdr.p = .015), AC (OR = 1.04, 95% CI = 1.01-1.06, fdr.p = .011), and AD (OR = 1.06, 95% CI = 1.02-1.09, fdr.p = .004). Subgroup analysis further confirmed that CD increased the risk of allergic disease as a whole (OR = 1.02, 95% CI = 1.00-1.03, fdr.p = .031), AC (OR = 1.03, 95% CI = 1.01-1.05, fdr.p = .012), AD (OR = 1.06, 95% CI = 1.02-1.09, fdr.p = 2E-05), AAS (OR = 1.05, 95% CI = 1.02-1.08, fdr.p = .002) and AR (OR = 1.03, 95% CI = 1.00-1.07, fdr.p = .025), UC increased the risk of AAS (OR = 1.02, 95% CI = 0.98-1.07, fdr.p = .038). MVMR results showed that after taking BMI as secondary exposure, the causal effects of IBD on AC, IBD on AD, CD on allergic disease as a whole, CD on AC, CD on AD, CD on AAS, and CD on AR were still statistically significant. No significant association was observed in the reverse MR analysis.

CONCLUSION

This Mendelian randomized study demonstrated that IBD is a risk factor for allergic diseases, which is largely attributed to its subtype CD increasing the risk of AC, AD, ASS, and AR. Further investigations are needed to explore the causal relationship between allergic diseases and IBD.

Increased risk of obstructive lung disease in inflammatory bowel disease: A population-based cohort study

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) is associated with disease manifestations in organs other than the gastrointestinal tract. In this study, we aimed to estimate the odds of obstructive lung disease (OLD) before IBD onset and the risk of OLD after IBD onset.

METHODS

In a nationwide population-based Danish cohort study from 1999 to 2018, individuals with IBD and OLD were identified using the Danish registries. Between 2003 and 2013, 24,238 individuals with IBD were identified and matched 1:10 with non-IBD individuals. Logistic regression was used to estimate the prevalence odds ratio for OLD before IBD onset. Time-to-event analysis was performed to explore the risk of OLD after IBD onset. In a sensitivity analysis, the time-to-event analysis was repeated using the composite outcome OLD and the separate outcomes, chronic obstructive pulmonary disease (COPD), asthma, and bronchiectasis.

RESULTS

Individuals with IBD were 60% more likely to have OLD before onset (adjusted odds ratio: 1.60, 95% confidence interval [CI]: 1.53-1.67). Furthermore, their risk of OLD was more than 40% higher after IBD diagnosis (adjusted hazard ratio [aHR]: 1.43, 95% CI: 1.37-1.49). The sensitivity analysis increased the risk to 60% (aHR: 1.63, 95% CI: 1.53-1.73). Similar results were found for COPD and asthma separately, whereas the risk of bronchiectasis increased more than 2-fold (aHR: 2.44, 95% CI: 1.91-3.11).

CONCLUSION

The odds of OLD before- and the risk following an IBD diagnosis were increased. We encourage physicians to be vigilant of pulmonary symptoms in persons with IBD and gastrointestinal symptoms in individuals with OLD.

Therapeutic effect of Yinhuapinggan granules mediated through the intestinal flora in mice infected with the H1N1 influenza virus

Objective

In this study, we examined the therapeutic effects of Yinhuapinggan granules (YHPGs) in influenza-infected mice. We also examined how YHPGs affect the composition of the intestinal flora and associated metabolites.

Methods

We used the nasal drip method to administer the influenza A virus (IAV) H1N1 to ICR mice. Following successful model construction, the mice were injected with 0.9% sterile saline and low (5.5 g/kg), medium (11 g/kg), and high (22 g/kg) doses of YHPGs. The pathological changes in the lungs and intestines were evaluated by gavage for 5 consecutive days. Detection of sIgA, IL-6, TNF-α, INF-γ, and TGF-β cytokine levels in serum by enzyme-linked immunosorbent assay. Real-time fluorescence quantitative polymerase chain reaction and Western blot were used to measure the mRNA and protein expression of the tight junction proteins claudin-1, occludin, and zonula occludens-1 (ZO-1) in the colon. To assess the influence of YHPGs on the intestinal microbiota, feces were obtained from the mice for 16s rRNA sequencing, and short-chain fatty acids (SCFAs) were measured in the feces.

Results

By reducing the production of pro-inflammatory cytokines and increasing the relative expression of claudin-1, occludin, and ZO-1 in colon tissues, YHPGs had a protective effect in tissues from the lungs and colon. When YHPGs were administered to mice with IAV infection, the relative abundance of Lactobacillus, Coprobacillus, Akkermansia, Prevotella, Oscillospira, and Ruminococcus increased, whereas the relative abundance of Desulfovibrio decreased.

Conclusion

The therapeutic mechanism of YHPGs against IAV infection in mice may be underpinned by modulation of the structural composition of colonic bacteria and regulation of SCFA production.

Approach to the diagnosis and management of dysbiosis

All microorganisms like bacteria, viruses and fungi that reside within a host environment are considered a microbiome. The number of bacteria almost equal that of human cells, however, the genome of these bacteria may be almost 100 times larger than the human genome. Every aspect of the physiology and health can be influenced by the microbiome living in various parts of our body. Any imbalance in the microbiome composition or function is seen as dysbiosis. Different types of dysbiosis are seen and the corresponding symptoms depend on the site of microbial imbalance. The contribution of the intestinal and extra-intestinal microbiota to influence systemic activities is through interplay between different axes. Whole body dysbiosis is a complex process involving gut microbiome and non-gut related microbiome. It is still at the stage of infancy and has not yet been fully understood. Dysbiosis can be influenced by genetic factors, lifestyle habits, diet including ultra-processed foods and food additives, as well as medications. Dysbiosis has been associated with many systemic diseases and cannot be diagnosed through standard blood tests or investigations. Microbiota derived metabolites can be analyzed and can be useful in the management of dysbiosis. Whole body dysbiosis can be addressed by altering lifestyle factors, proper diet and microbial modulation. The effect of these interventions in humans depends on the beneficial microbiome alteration mostly based on animal studies with evolving evidence from human studies. There is tremendous potential for the human microbiome in the diagnosis, treatment, and prognosis of diseases, as well as, for the monitoring of health and disease in humans. Whole body system-based approach to the diagnosis of dysbiosis is better than a pure taxonomic approach. Whole body dysbiosis could be a new therapeutic target in the management of various health conditions.

Therapeutic Effects of Lifei Decoction in a Murine Model of COPD Induced by LPS and Cigarette Smoke

Introduction

The Lifei Decoction (LD) is a commonly utilized Chinese medicine for the treatment of sepsis and bronchial inflammation. However, its therapeutic potential in chronic obstructive pulmonary disease (COPD) remains unknown. Therefore, the objective of this study was to investigate the therapeutic efficacy and underlying mechanism of LD in a mouse model of COPD induced by cigarette smoke (CS) combined with lipopolysaccharide (LPS).

Methods

Hematoxylin-eosin (H&E) staining was employed to observe the pathological alterations in lung tissue, while ELISA was utilized for the detection of levels of inflammatory factors in both lung tissue and bronchoalveolar lavage fluid (BALF). Additionally, Western blot analysis was conducted to assess the expression of p-NF-κB, GDF11, ZO-1, and Occludin-1 proteins. The changes in intestinal flora were evaluated using the viable bacteria count method.

Results

The administration of LD demonstrates significant efficacy in mitigating pulmonary tissue damage in a murine model, while concurrently inhibiting the activation of the inflammatory pathway NF-κB to attenuate the levels of pro-inflammatory factors. Moreover, LD exhibits the capacity to enhance the expression of intestinal functional proteins ZO-1 and Occludin-1, thereby rectifying dysbiosis within the gut microbiota.

Conclusion

The LD shows great promise as a potential treatment for COPD.

The causality of gut microbiota on onset and progression of sepsis: a bi-directional Mendelian randomization analysis

Background

Several observational studies have proposed a potential link between gut microbiota and the onset and progression of sepsis. Nevertheless, the causality of gut microbiota and sepsis remains debatable and warrants more comprehensive exploration.

Methods

We conducted a two-sample Mendelian randomization (MR) analysis to test the causality between gut microbiota and the onset and progression of sepsis. The genome-wide association study (GWAS) summary statistics for 196 bacterial traits were extracted from the MiBioGen consortium, whereas the GWAS summary statistics for sepsis and sepsis-related outcomes came from the UK Biobank. The inverse-variance weighted (IVW) approach was the primary method used to examine the causal association. To complement the IVW method, we utilized four additional MR methods. We performed a series of sensitivity analyses to examine the robustness of the causal estimates.

Results

We assessed the causality of 196 bacterial traits on sepsis and sepsis-related outcomes. Genus Coprococcus2 [odds ratio (OR) 0.81, 95% confidence interval (CI) (0.69-0.94), p = 0.007] and genus Dialister (OR 0.85, 95% CI 0.74-0.97, p = 0.016) had a protective effect on sepsis, whereas genus Ruminococcaceae UCG011 (OR 1.10, 95% CI 1.01-1.20, p = 0.024) increased the risk of sepsis. When it came to sepsis requiring critical care, genus Anaerostipes (OR 0.49, 95% CI 0.31-0.76, p = 0.002), genus Coprococcus1 (OR 0.65, 95% CI 0.43-1.00, p = 0.049), and genus Lachnospiraceae UCG004 (OR 0.51, 95% CI 0.34-0.77, p = 0.001) emerged as protective factors. Concerning 28-day mortality of sepsis, genus Coprococcus1 (OR 0.67, 95% CI 0.48-0.94, p = 0.020), genus Coprococcus2 (OR 0.48, 95% CI 0.27-0.86, p = 0.013), genus Lachnospiraceae FCS020 (OR 0.70, 95% CI 0.52-0.95, p = 0.023), and genus Victivallis (OR 0.82, 95% CI 0.68-0.99, p = 0.042) presented a protective effect, whereas genus Ruminococcus torques group (OR 1.53, 95% CI 1.00-2.35, p = 0.049), genus Sellimonas (OR 1.25, 95% CI 1.04-1.50, p = 0.019), and genus Terrisporobacter (OR 1.43, 95% CI 1.02-2.02, p = 0.040) presented a harmful effect. Furthermore, genus Coprococcus1 (OR 0.42, 95% CI 0.19-0.92, p = 0.031), genus Coprococcus2 (OR 0.34, 95% CI 0.14-0.83, p = 0.018), and genus Ruminiclostridium6 (OR 0.43, 95% CI 0.22-0.83, p = 0.012) were associated with a lower 28-day mortality of sepsis requiring critical care.

Conclusion

This MR analysis unveiled a causality between the 21 bacterial traits and sepsis and sepsis-related outcomes. Our findings may help the development of novel microbiota-based therapeutics to decrease the morbidity and mortality of sepsis.

Genital Dysbiosis and Different Systemic Immune Responses Based on the Trimester of Pregnancy in SARS-CoV-2 Infection

Respiratory infections are common in pregnancy with conflicting evidence supporting their association with neonatal congenital anomalies, especially during the first trimester. We profiled cytokine and chemokine systemic responses in 242 pregnant women and their newborns after SARS-CoV-2 infection, acquired in different trimesters. Also, we tested transplacental IgG passage and maternal vaginal-rectal microbiomes. IgG transplacental passage was evident, especially with infection acquired in the first trimester. G-CSF concentration-involved in immune cell recruitment-decreased in infected women compared to uninfected ones: a beneficial event for the reduction of inflammation but detrimental to ability to fight infections at birth. The later the infection was acquired, the higher the systemic concentration of IL-8, IP-10, and MCP-1, associated with COVID-19 disease severity. All infected women showed dysbiosis of vaginal and rectal microbiomes, compared to uninfected ones. Two newborns tested positive for SARS-CoV-2 within the first 48 h of life. Notably, their mothers had acute infection at delivery. Although respiratory infections in pregnancy are reported to affect babies' health, with SARS-CoV-2 acquired early during gestation this risk seems low because of the maternal immune response. The observed vaginal and rectal dysbiosis could be relevant for neonatal microbiome establishment, although in our series immediate neonatal outcomes were reassuring.

Longitudinal profiling of the microbiome at four body sites reveals core stability and individualized dynamics during health and disease

To understand the dynamic interplay between the human microbiome and host during health and disease, we analyzed the microbial composition, temporal dynamics, and associations with host multi-omics, immune, and clinical markers of microbiomes from four body sites in 86 participants over 6 years. We found that microbiome stability and individuality are body-site specific and heavily influenced by the host. The stool and oral microbiome are more stable than the skin and nasal microbiomes, possibly due to their interaction with the host and environment. We identify individual-specific and commonly shared bacterial taxa, with individualized taxa showing greater stability. Interestingly, microbiome dynamics correlate across body sites, suggesting systemic dynamics influenced by host-microbial-environment interactions. Notably, insulin-resistant individuals show altered microbial stability and associations among microbiome, molecular markers, and clinical features, suggesting their disrupted interaction in metabolic disease. Our study offers comprehensive views of multi-site microbial dynamics and their relationship with host health and disease.

Bufei Huoxue capsule attenuates COPD-related inflammation and regulates intestinal microflora, metabolites

Background: Bufei Huoxue capsule (BFHX) is widely used for the clinical treatment of chronic obstructive pulmonary disease (COPD) in China. Objectives: The aim of this study is to explore the effects on COPD and the underlying mechanism of BFHX. The process and methods: In this study, we established a COPD mouse model through cigarette smoke (CS) exposure in combination with lipopolysaccharide (LPS) intratracheal instillation. Subsequently, BFHX was orally administrated to COPD mice, and their pulmonary function, lung pathology, and lung inflammation, including bronchoalveolar lavage fluid (BALF) cell count and classification and cytokines, were analyzed. In addition, the anti-oxidative stress ability of BFHX was detected by Western blotting, and the bacterial diversity, abundance, and fecal microbiome were examined using 16S rRNA sequencing technology. Outcome: BFHX was shown to improve pulmonary function, suppress lung inflammation, decrease emphysema, and increase anti-oxidative stress, whereas 16S rRNA sequencing indicated that BFHX can dynamically regulate the diversity, composition, and distribution of the intestinal flora microbiome and regulate the lysine degradation and phenylalanine metabolism of COPD mice. These results highlight another treatment option for COPD and provide insights into the mechanism of BFHX.

Faecal microbial transfer and complex carbohydrates mediate protection against COPD

OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is a major cause of global illness and death, most commonly caused by cigarette smoke. The mechanisms of pathogenesis remain poorly understood, limiting the development of effective therapies. The gastrointestinal microbiome has been implicated in chronic lung diseases via the gut-lung axis, but its role is unclear.

DESIGN

Using an in vivo mouse model of cigarette smoke (CS)-induced COPD and faecal microbial transfer (FMT), we characterised the faecal microbiota using metagenomics, proteomics and metabolomics. Findings were correlated with airway and systemic inflammation, lung and gut histopathology and lung function. Complex carbohydrates were assessed in mice using a high resistant starch diet, and in 16 patients with COPD using a randomised, double-blind, placebo-controlled pilot study of inulin supplementation.

RESULTS

FMT alleviated hallmark features of COPD (inflammation, alveolar destruction, impaired lung function), gastrointestinal pathology and systemic immune changes. Protective effects were additive to smoking cessation, and transfer of CS-associated microbiota after antibiotic-induced microbiome depletion was sufficient to increase lung inflammation while suppressing colonic immunity in the absence of CS exposure. Disease features correlated with the relative abundance of Muribaculaceae, Desulfovibrionaceae and Lachnospiraceae family members. Proteomics and metabolomics identified downregulation of glucose and starch metabolism in CS-associated microbiota, and supplementation of mice or human patients with complex carbohydrates improved disease outcomes.

CONCLUSION

The gut microbiome contributes to COPD pathogenesis and can be targeted therapeutically.

Gut Microbiome and Transcriptomic Changes in Cigarette Smoke-Exposed Mice Compared to COPD and CD Patient Datasets

Chronic obstructive pulmonary disease (COPD) patients and smokers have a higher incidence of intestinal disorders. The aim of this study was to gain insight into the transcriptomic changes in the lungs and intestines, and the fecal microbial composition after cigarette smoke exposure. Mice were exposed to cigarette smoke and their lung and ileum tissues were analyzed by RNA sequencing. The top 15 differentially expressed genes were investigated in publicly available gene expression datasets of COPD and Crohn's disease (CD) patients. The murine microbiota composition was determined by 16S rRNA sequencing. Increased expression of MMP12, GPNMB, CTSK, CD68, SPP1, CCL22, and ITGAX was found in the lungs of cigarette smoke-exposed mice and COPD patients. Changes in the intestinal expression of CD79B, PAX5, and FCRLA were observed in the ileum of cigarette smoke-exposed mice and CD patients. Furthermore, inflammatory cytokine profiles and adhesion molecules in both the lungs and intestines of cigarette smoke-exposed mice were profoundly changed. An altered intestinal microbiota composition and a reduction in bacterial diversity was observed in cigarette smoke-exposed mice. Altered gene expression in the murine lung was detected after cigarette smoke exposure, which might simulate COPD-like alterations. The transcriptomic changes in the intestine of cigarette smoke-exposed mice had some similarities with those of CD patients and were associated with changes in the intestinal microbiome. Future research could benefit from investigating the specific mechanisms underlying the observed gene expression changes due to cigarette smoke exposure, focusing on identifying potential therapeutic targets for COPD and CD.