Lung inflammation and disease: A perspective on microbial homeostasis and metabolism

Inhaled polystyrene microplastics impaired lung function through pulmonary flora/TLR4-mediated iron homeostasis imbalance

Microplastics (MPs) have been found in the air, human nasal cavity, and lung, suggesting that the respiratory tract is one of the important exposure routes for MPs. The lung is a direct target organ for injury from inhaled MPs, but data on lung injury from longer-term exposure to environmental doses of MPs are limited, and the mechanisms remain unclear. Here, C57BL/6 J mice were treated with 5 μm polystyrene (PS)-MPs by intratracheal instillation (0.6, 3, and 15 mg/kg) for 60 days to establish MPs exposure model. We found that PS-MPs lead to increased collagen fibers and decreased lung barrier permeability and lung function in lung tissue. Mechanistically, the abundance of gram-negative bacteria in the pulmonary flora increased after inhalation of PS-MPs, causing lipopolysaccharide (LPS) release. The expression of Toll-like receptor 4 (TLR4), the key receptor of LPS, was increased, and ferroptosis occurred in lung tissue cells. Further in vitro intervention experiments were performed, pulmonary flora/TLR4-induced imbalance of lung iron homeostasis is an important mechanism of PS-MPs-induced lung injury. Our study provides new evidence for lung injury caused by environmental doses of MPs and strategies to prevent it through longer-term dynamic observation.

Quantitative evaluation of bronchoalveolar lavage for the treatment of severe Mycoplasma pneumoniae pneumonia in children-A new complementary index: Bronchial Insufflation Sign Score

OBJECTIVE

The aim of this study was to investigate the value of Broncoplasma Insufflation Sign in lung ultrasound signs in assessing the efficacy of bronchoalveolar lavage in severe Mycoplasma pneumoniae pneumonia in children.

METHODS

Forty-seven children with severe Mycoplasma pneumoniae pneumonia were treated with medication and bronchial lavage. Laboratory and imaging results were collected, and lung ultrasonography was performed before bronchoalveolar lavage and 1, 3, and 7 days after lavage to record changes in Bronchial Insufflation Sign and changes in the extent of solid lung lesions. Factors affecting the effectiveness of bronchoalveolar lavage were analyzed using logistic regression and other factors.

RESULTS

Bronchial Insufflation Sign Score and the extent of lung solid lesions were the factors affecting the effectiveness of bronchoalveolar lavage treatment. The smaller the area of lung solid lesions and the higher the Bronchial Insufflation Sign Score, the more effective the results of bronchoalveolar lavage treatment were, and the difference was statistically significant, with a difference of p < 0.05. The Bronchial Insufflation Sign Score had the highest sensitivity and specificity for the prediction of the efficacy of bronchoalveolar lavage treatment in the first 7 days after the treatment.

CONCLUSION

Bronchial Insufflation Sign Score combined with the extent of solid lung lesions can assess the efficacy of bronchoalveolar lavage in the treatment of severe Mycoplasma pneumoniae pneumonia in children; lung ultrasound is a timely and effective means of assessing the efficacy of bronchoalveolar lavage.

Single-cell sequencing reveals lung cell fate evolution initiated by smoking to explore gene predictions of correlative diseases

Continuous smoking leads to adaptive regulation and physiological changes in lung tissue and cells, and is an inductive factor for many diseases, making smokers face the risk of malignant and nonmalignant diseases. The impact of research in this area is getting more and more in-depth, but the stimulant effect, mechanism of action and response mechanism of the main cells in the lungs caused by smoke components have not yet been fully elucidated, and the early diagnosis and identification of various diseases induced by smoke toxins have not yet formed a systematic relationship method. In this study, single-cell transcriptome data were generated from three lung samples of smokers and nonsmokers through scRNA-seq technology, revealing the influence of smoking on lung tissue and cells and the changes in immune response. The results show that: through UMAP cell clustering, 16 intermediate cell states of 23 cell clusters of the four main cell types in the lung are revealed, the differences of the main cell groups between smokers and nonsmokers are explained, and the human lung cells are clarified. Components and their marker genes, screen for new marker genes that can be used in the evolution of intermediate-state cells, and at the same time, the analysis of lung cell subgroups reveals the changes in the intermediate state of cells under smoke stimulation, forming a subtype intermediate state cell map. Pseudo-time ordering analysis, to determine the pattern of dynamic processes experienced by cells, differential expression analysis of different branch cells, to clarify the expression rules of cells at different positions, to clarify the evolution process of the intermediate state of cells, and to clarify the response of lung tissue and cells to smoke components mechanism. The development of this study provides new diagnosis and treatment ideas for early disease detection, identification, disease prevention and treatment of patients with smoking-related diseases, and lays a theoretical foundation based on cell and molecular regulation.

Major alteration of Lung Microbiome and the Host Reaction in critically ill COVID-19 Patients with high viral load

Background

Patients with COVID-19 under invasive mechanical ventilation are at higher risk of developing ventilator-associated pneumonia (VAP), associated with increased healthcare costs, and unfavorable prognosis. The underlying mechanisms of this phenomenon have not been thoroughly dissected. Therefore, this study attempted to bridge this gap by performing a lung microbiota analysis and evaluating the host immune responses that could drive the development of VAP.

Materials and methods

In this prospective cohort study, mechanically ventilated patients with confirmed SARS-CoV-2 infection were enrolled. Nasal swabs (NS), endotracheal aspirates (ETA), and blood samples were collected initially within 12 hours of intubation and again at 72 hours post-intubation. Plasma samples underwent cytokine and metabolomic analyses, while NS and ETA samples were sequenced for lung microbiome examination. The cohort was categorized based on the development of VAP. Data analysis was conducted using RStudio version 4.3.1.

Results

In a study of 36 COVID-19 patients on mechanical ventilation, significant differences were found in the nasal and pulmonary microbiome, notably in Staphylococcus and Enterobacteriaceae, linked to VAP. Patients with VAP showed a higher SARS-CoV-2 viral load, elevated neutralizing antibodies, and reduced inflammatory cytokines, including IFN-δ, IL-1β, IL-12p70, IL-18, IL-6, TNF-α, and CCL4. Metabolomic analysis revealed changes in 22 metabolites in non-VAP patients and 27 in VAP patients, highlighting D-Maltose-Lactose, Histidinyl-Glycine, and various phosphatidylcholines, indicating a metabolic predisposition to VAP.

Conclusions

This study reveals a critical link between respiratory microbiome alterations and ventilator-associated pneumonia in COVID-19 patients, with elevated SARS-CoV-2 levels and metabolic changes, providing novel insights into the underlying mechanisms of VAP with potential management and prevention implications.

Microbiota Alterations in Lung, Ileum, and Colon of Guinea Pigs with Cough Variant Asthma

Alterations in the microbiota composition, or ecological dysbiosis, have been implicated in the development of various diseases, including allergic diseases and asthma. Examining the relationship between microbiota alterations in the host and cough variant asthma (CVA) may facilitate the discovery of novel therapeutic strategies. To elucidate the diversity and difference of microbiota across three ecological niches, we performed 16S rDNA amplicon sequencing on lung, ileum, and colon samples. We assessed the levels of interleukin-12 (IL-12) and interleukin-13 (IL-13) in guinea pig bronchoalveolar lavage fluid using the enzyme-linked immunosorbent assay (ELISA). We applied Spearman's analytical method to evaluate the correlation between microbiota and cytokines. The results demonstrated that the relative abundance, α-diversity, and β-diversity of the microbial composition of the lung, ileum, and colon varied considerably. The ELISA results indicated a substantial increase in the level of IL-13 and a decreasing trend in the level of IL-12 in the CVA guinea pigs. The Spearman analysis identified a correlation between Mycoplasma, Faecalibaculum, and Ruminococcus and the inflammatory factors in the CVA guinea pigs. Our guinea pig model showed that core microorganisms, such as Mycoplasma in the lung, Faecalibaculum in the ileum, and Ruminococcus in the colon, may play a crucial role in the pathogenesis of CVA. The most conspicuous changes in the ecological niche were observed in the guinea pig ileum, followed by the lung, while relatively minor changes were observed in the colon. Notably, the microbial structure of the ileum niche approximated that of the colon niche. Therefore, the results of this study suggest that CVA development is closely related to the dysregulation of ileal, lung, and colon microbiota and the ensuing inflammatory changes in the lung.

Lung injuries induced by ozone exposure in female mice: Potential roles of the gut and lung microbes

Ozone (O3) is one of the most harmful pollutants affecting health. However, the potential effects of O3 exposure on microbes in the gut-lung axis related to lung injuries remain elusive. In this study, female mice were exposed to 0-, 0.5- and 1-ppm O3 for 28 days, followed by routine blood tests, lung function tests and histopathological examination of the colon, nasal cavity and lung. Mouse faeces and lungs were collected for 16s rRNA sequencing to assess the overall microbiological profile and screen for key differential enriched microbes (DEMs). The key DEMs in faecal samples were Butyricimonas, Rikenellaceae RC9 and Escherichia-Shigella, whereas those in lung samples were DNF00809, Fluviicola, Bryobacter, Family XII AD3011 group, Sharpea, MND1 and unclassified Phycisphaeraceae. After a search in microbe-disease databases, these key DEMs were found to be associated with lung diseases such as lung neoplasms, cystic fibrosis, pneumonia, chronic obstructive pulmonary disease, respiratory distress syndrome and bronchiectasis. Subsequently, we used transcriptomic data from Gene Expression Omnibus (GEO) with exposure conditions similar to those in this study to cross-reference with Comparative Toxicogenomic Database (CTD). Il-6 and Ccl2 were identified as the key causative genes and were validated. The findings of this study suggest that exposure to O3 leads to significant changes in the microbial composition of the gut and lungs. These changes are associated with increased levels of inflammatory factors in the lungs and impaired lung function, resulting in an increased risk of lung disease. Altogether, this study provides novel insights into the role of microbes present in the gut-lung axis in O3 exposure-induced lung injury.

High throughput sequencing technology reveals alteration of lower respiratory tract microbiome in severe aspiration pneumonia and its association with inflammation

BACKGROUND

Aspiration pneumonia is a common and severe clinical condition. The microbiome present in the lower respiratory tract plays a crucial role in regulating human inflammatory response. However, the relationship between the altered lower respiratory tract microbiome and inflammation in aspiration pneumonia remains inadequately explored.

PURPOSE

To investigate the alteration of the lower respiratory tract microbiome in severe aspiration pneumonia patients and explore the potential correlation between microbiome components and inflammatory response.

METHOD

Patients in the severe aspiration pneumonia group and control group were enrolled from the intensive care unit of Jinshan Hospital, Fudan University between December 31, 2020 and August 19, 2021. Sputum specimens were collected from all participants and subsequently subjected to 16S rDNA high throughput sequencing technology. The concentration of inflammatory cytokines in serum was measured using enzyme-linked immunosorbent assay (ELISA) kits, and collected data including patients' demographic information, clinical data, and laboratory examination results were recorded for further analysis.

RESULTS

Alteration in the lower respiratory tract microbiome was observed in severe aspiration pneumonia. Compared to the control group, a significant decrease in the relative abundance of Firmicutes was found at the phylum level (P < 0.01). At the family level, the relative abundance of Corynebacteriaceae, Enterobacteriaceae and Enterococcaceae increased significantly (P < 0.001, P < 0.05, P < 0.01). There were no significant differences in community diversity of the lower respiratory tract between the two groups. Patients in the severe aspiration pneumonia group exhibited significantly higher levels of inflammation compared to those in the control group. Correlation analysis showed that the relative abundance of Corynebacteriaceae was positively correlated with the expression level of IL-1β and IL-18 (P = 0.002, P = 0.02); the relative abundance of Enterobacteriaceae was negatively correlated with IL-4 (P = 0.011); no other significant correlations have been identified between microbiome and inflammatory indicators thus far (P > 0.05).

CONCLUSIONS

Alteration of the lower respiratory tract microbiome is critically involved in inflammation and disease progression in severe cases of aspiration pneumonia. The potential inflammation regulation properties of the microbiome hold promising value for developing novel therapeutic approaches aimed at mitigating the severity of the disease.

[Relationship Between Dynamic Compliance and Airway Resistance and Infection Indicators in Elderly Patients With Lung Infection After Radiotherapy for Esophageal Cancer]

Objective

To investigate the performance of using lung dynamic compliance (Cdyn) and airway resistance (RAW) levels to predict lung infection in elderly esophageal cancer patients who have undergone radiotherapy.

Methods

A total of 298 elderly esophageal cancer patients who received radiotherapy at Shanxi Fenyang Hospital between October 2017 and July 2022 were retrospectively enrolled and their clinical data were collected. The patients were divided into an infection group (124 cases) and a non-infection group (174 cases) according to their status of lung infection. Then, in the infection group, CURB-65 score was used to assess the severity of the patients' lung infection and the patients were further divided into subgroups accordingly, with 36 cases in the mild infection subgroup, 58 cases in the moderate infection subgroup, and 30 cases in the severe infection subgroup. The levels of Cdyn, RAW, and infection indicators, including serum procalcitonin (PCT), interleukin-6 (IL-6), and angiotensin Ⅱ (Ang Ⅱ), were measured in both groups of patients and the differences in the findings were compared between the infection and the non-infection groups and among patients with infection of varying degrees of severity. The correlation between Cdyn and RAW and the levels of PCT, IL-6, and Ang Ⅱ was analyzed. Receiver operating characteristic (ROC) curve was used to evaluate the performance of predicting infection with Cdyn and RAW.

Results

The Cdyn level of patients in the infection group was lower than that of patients in the non-infection group, while the RAW level of the infection group was higher than that of the non-infection group (P<0.05). Among the infection subgroup, the level of Cdyn of the mild infection subgroup was higher than those of the moderate and severe infection subgroups, while the levels of RAW, PCT, IL-6, and Ang Ⅱ of the mild infection subgroup were lower than those of the moderate severe subgroups. The level of Cdyn of the moderate infection subgroup was higher than that of the severe infection subgroup, while the RAW, PCT, IL-6, and Ang Ⅱ levels of the moderate infection subgroup were lower than those of the severe infection subgroup, with all difference being statistically significant (P<0.05). The Cdyn level of patients with lung infection was negatively correlated with PCT, IL-6, and Ang Ⅱ levels and the severity of infection (r=-0.501, -0.430, -0.367, and -0.484, respectively, P<0.05), while RAW was positively correlated with PCT, IL-6, and Ang Ⅱ levels and the severity of infection (r=0.483, 0.395, 0.374, and 0.423, respectively, P<0.05). The area under the curve (AUC) of Cdyn and RAW for predicting lung infection in elderly patients with esophageal cancer after radiotherapy were 0.898 (95% confidence interval [CI]: 0.857-0.930) and 0.823 (95% CI: 0.775-0.865), respectively, and the AUC of combined evaluation of Cdyn and RAW was 0.959 (95% CI: 0.930-0.979), which suggested that the predictive performance of combined evaluation was better than evaluation with Cdyn or RAW alone.

Conclusion

When elderly esophageal cancer patients develop lung infection after radiotherapy, their Cdyn level is decreased, while the levels of RAW, PCT, IL-6, and Ang Ⅱ are increased. In addition, the levels of Cdyn and RAW are correlated with the PCT, IL-6, and Ang Ⅱ levels. The combined use of Cdyn and RAW shows good performance for predicting lung infection in patients.

Optimization strategy for the early timing of bronchoalveolar lavage treatment for children with severe mycoplasma pneumoniae pneumonia

BACKGROUND

Early evaluation of severe mycoplasma pneumoniae pneumonia (SMPP) and the prompt utilization of fiberoptic bronchoscopic manipulation can effectively alleviate complications and restrict the progression of sequelae. This study aim to establish a nomogram forecasting model for SMPP in children and explore an optimal early therapeutic bronchoalveolar lavage (TBAL) treatment strategy.

METHODS

This retrospective study included children with mycoplasma pneumoniae pneumonia (MPP) from January 2019 to December 2021. Multivariate logistic regression analysis was used to screen independent risk factors for SMPP and establish a nomogram model. The bootstrap method was employed and a receiver operator characteristic (ROC) curve was drawn to evaluate the accuracy and robustness of the model. Kaplan-Meier analysis was used to assess the effect of lavage and hospitalization times.

RESULTS

A total of 244 cases were enrolled in the study, among whom 68 with SMPP and 176 with non-SMPP (NSMPP). A prediction model with five independent risk factors: left upper lobe computed tomography (CT) score, sequential organ failure assessment (SOFA) score, acute physiology and chronic health assessment (APACHE) II score, bronchitis score (BS), and c-reactive protein (CRP) was established based on the multivariate logistic regression analysis. The ROC curve of the prediction model showed the area under ROC curve (AUC) was 0.985 (95% confidence interval (CI) 0.972-0.997). The Hosmer-Lemeshow goodness-of-fit test results showed that the nomogram model predicted the risk of SMPP well (χ2 = 2.127, P = 0.977). The log-rank result suggested that an early BAL treatment could shorten MPP hospitalization time (P = 0.0057).

CONCLUSION

This nomogram model, based on the left upper lobe CT score, SOFA score, APACHE II score, BS, and CRP level, represents a valuable tool to predict the risk of SMPP in children and optimize the timing of TBAL.

Lung microbiome and origins of the respiratory diseases

The studies on the composition of the human microbiomes in healthy individuals, its variability in the course of inflammation, infection, antibiotic therapy, diets and different pathological conditions have revealed their intra and inter-kingdom relationships. The lung microbiome comprises of major species members of the phylum Bacteroidetes, Firmicutes, Actinobacteria, Fusobacteria and Proteobacteria, which are distributed in ecological niches along nasal cavity, nasopharynx, oropharynx, trachea and in the lungs. Commensal and pathogenic species are maintained in equilibrium as they have strong relationships. Bacterial overgrowth after dysbiosis and/or imbalanced of CD4⁺ helper T cells, CD8⁺ cytotoxic T cells and regulatory T cells (Treg) populations can promote lung inflammatory reactions and distress, and consequently acute and chronic respiratory diseases. This review is aimed to summarize the latest advances in resident lung microbiome and its participation in most common pulmonary infections and pneumonia, community-acquired pneumonia (CAP), ventilator-associated pneumonia (VAP), immunodeficiency associated pneumonia, SARS-CoV-2-associated pneumonia, acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD). We briefly describe physiological and immunological mechanisms that selectively create advantages or disadvantages for relative growth of pathogenic bacterial species in the respiratory tract. At the end, we propose some directions and analytical methods that may facilitate the identification of key genera and species of resident and transient microbes involved in the respiratory diseases' initiation and progression.

Exploring the complex relationship between the lung microbiome and ventilator-associated pneumonia

INTRODUCTION

Understanding the presence and function of a diverse lung microbiome in acute lung infections, particularly ventilator-associated pneumonia (VAP), is still limited, evidencing significant gaps in our knowledge.

AREAS COVERED

In this comprehensive narrative review, we aim to elucidate the contribution of the respiratory microbiome in the development of VAP by examining the current knowledge on the interactions among microorganisms. By exploring these intricate connections, we endeavor to enhance our understanding of the disease's pathophysiology and pave the way for novel ideas and interventions in studying the respiratory tract microbiome.

EXPERT OPINION

The conventional perception of lungs as sterile is deprecated since it is currently recognized the existence of a diverse microbial community within them. However, despite extensive research on the role of the respiratory microbiome in healthy lungs, respiratory chronic diseases and acute lung infections such as pneumonia are not fully understood. It is crucial to investigate further the relationship between the pathophysiology of VAP and the pulmonary microbiome, elucidating the mechanisms underlying the interactions between the microbiome, host immune response and mechanical ventilation for the development of VAP.

Analysis of the correlation between BMI and respiratory tract microbiota in acute exacerbation of COPD

Objective

To investigate the distribution differences in the respiratory tract microbiota of AECOPD patients in different BMI groups and explore its guiding value for treatment.

Methods

Sputum samples of thirty-eight AECOPD patients were collected. The patients were divided into low, normal and high BMI group. The sputum microbiota was sequenced by 16S rRNA detection technology, and the distribution of sputum microbiota was compared. Rarefaction curve, α-diversity, principal coordinate analysis (PCoA) and measurement of sputum microbiota abundance in each group were performed and analyzed by bioinformatics methods.

Results

1. The rarefaction curve in each BMI group reached a plateau. No significant differences were observed in the OTU total number or α-diversity index of microbiota in each group. PCoA showed significant differences in the distance matrix of sputum microbiota between the three groups, which was calculated by the Binary Jaccard and the Bray Curtis algorithm. 2. At the phylum level, most of the microbiota were Proteobacteria, Bacteroidetes Firmicutes, Actinobacteria, and Fusobacteria. At the genus level, most were Streptococcus, Prevotella, Haemophilus, Neisseria and Bacteroides. 3. At the phylum level, the abundance of Proteobacteria in the low group was significantly higher than that in normal and high BMI groups, the abundances of Firmicutes in the low and normal groups were significantly lower than that in high BMI groups. At the genus level, the abundance of Haemophilus in the low group was significantly higher than that in high BMI group, and the abundances of Streptococcus in the low and normal BMI groups were significantly lower than that in the high BMI group.

Conclusions

1. The sputum microbiota of AECOPD patients in different BMI groups covered almost all microbiota, and BMI had no significant association with total number of respiratory tract microbiota or α-diversity in AECOPD patients. However, there was a significant difference in the PCoA between different BMI groups. 2. The microbiota structure of AECOPD patients differed in different BMI groups. Gram-negative bacteria (G-) in the respiratory tract of patients predominated in the low BMI group, while gram-positive bacteria (G+) predominated in the high BMI group.

Multi-omics association analysis reveals interactions between the oropharyngeal microbiome and the metabolome in pediatric patients with influenza A virus pneumonia

Children are at high risk for influenza A virus (IAV) infections, which can develop into severe illnesses. However, little is known about interactions between the microbiome and respiratory tract metabolites and their impact on the development of IAV pneumonia in children. Using a combination of liquid chromatography tandem mass spectrometry (LC-MS/MS) and 16S rRNA gene sequencing, we analyzed the composition and metabolic profile of the oropharyngeal microbiota in 49 pediatric patients with IAV pneumonia and 42 age-matched healthy children. The results indicate that compared to healthy children, children with IAV pneumonia exhibited significant changes in the oropharyngeal macrobiotic structure (p = 0.001), and significantly lower microbial abundance and diversity (p < 0.05). These changes came with significant disturbances in the levels of oropharyngeal metabolites. Intergroup differences were observed in 204 metabolites mapped to 36 metabolic pathways. Significantly higher levels of sphingolipid (sphinganine and phytosphingosine) and propanoate (propionic acid and succinic acid) metabolism were observed in patients with IAV pneumonia than in healthy controls. Using Spearman’s rank-correlation analysis, correlations between IAV pneumonia-associated discriminatory microbial genera and metabolites were evaluated. The results indicate significant correlations and consistency in variation trends between Streptococcus and three sphingolipid metabolites (phytosphingosine, sphinganine, and sphingosine). Besides these three sphingolipid metabolites, the sphinganine-to-sphingosine ratio and the joint analysis of the three metabolites indicated remarkable diagnostic efficacy in children with IAV pneumonia. This study confirmed significant changes in the characteristics and metabolic profile of the oropharyngeal microbiome in pediatric patients with IAV pneumonia, with high synergy between the two factors. Oropharyngeal sphingolipid metabolites may serve as potential diagnostic biomarkers of IAV pneumonia in children.

Diarrhea with deficiency kidney-yang syndrome caused by adenine combined with Folium senna was associated with gut mucosal microbiota

The present study aims to study and analyze the characteristics of gut mucosal microbiota in diarrhea mice with deficiency kidney-yang syndrome. Ten male mice were randomly divided into the control group and the model group. Diarrhea mice model with deficiency kidney-yang syndrome was established by adenine combined with Folium sennae. The kidney structure was observed by hematoxylin-eosin (HE) staining. Serum Na+-K+-ATP-ase and Ca2+-Mg2+-ATP-ase were detected by enzyme-linked immunosorbent assay (ELISA). The characteristics of gut mucosal microbiota were analyzed by performing third-generation high-throughput sequencing. The results showed that the model mice exhibit obvious structural damage to the kidney. Serum Na+-K+-ATP-ase and Ca2+-Mg2+-ATP-ase levels showed a decreased trend in the model group. The diversity and community structure of the gut mucosal microbiota improved in the model group. Dominant bacteria like Candidatus Arthromitus, Muribaculum, and Lactobacillus reuteri varied significantly at different taxonomic levels. The characteristic bacteria like Bacteroides, Erysipelatoclostridium, Anaerotignum, Akkermansia muciniphila, Clostridium cocleatum, Bacteroides vulgatus, and Bacteroides sartorii were enriched in the model group. A correlation analysis described that Erysipelatoclostridium was positively correlated with Na+-K+-ATP-ase and Ca2+-Mg2+-ATP-ase levels, while Anaerotignum exhibited an opposite trend. Together, adenine combined with Folium sennae damaged the structure of the kidney, affected energy metabolism, and caused disorders of gut mucosal microbiota in mice. Bacteroides, Erysipelatoclostridium, and Anaerotignum showed significant inhibition or promotion effects on energy metabolism. Besides, Akkermansia muciniphila, Clostridium cocleatum, Bacteroides vulgatus, and Bacteroides sartorii might be the characteristic species of gut mucosal microbiota responsible for causing diarrhea with deficiency kidney-yang syndrome.

Potential Implications of the Lung Microbiota in Patients with Chronic Obstruction Pulmonary Disease and Non-Small Cell Lung Cancer

Recently, chronic obstructive pulmonary disease (COPD) has been considered as a common risk factor of non-small cell lung cancer (NSCLC). However, very few studies have been conducted on the effects of COPD on the lung microbiota in patients with NSCLC. To identify the lung microbiota in patients with COPD and NSCLC (CN), the microbiome of the induced sputa of 90 patients was analyzed using 16S rDNA sequencing. The results showed no significant differences in the bacterial diversities of induced sputa among patients with COPD, NSCLC, and CN and no intrinsic differences among patients with different pathological types of lung cancer. After surgical operation, the diversities of the induced sputa in patients with CN significantly decreased. More remarkably, both the microbial community phenotypes and the components of the induced sputa in patients with CN obviously differed from those in patients with COPD or NSCLC. The relative abundances of Streptococcus, Veillonella, Moraxella, and Actinomyces significantly decreased, but those of Neisseria and Acinetobacter significantly increased in patients with CN compared with those in patients with COPD or NSCLC alone, resulting in increased Gram-negative microbiota and, therefore, in potential pathogenicity and stress tolerance, as well as in enhancement of microbial glycolipid metabolism, amino acid metabolism, and oxidative stress. Although COPD did not affect the number of pulmonary flora species in patients with NSCLC, these significant alterations in the microbial populations, phenotypes, and functions of induced sputa due to COPD would contribute to inflammation-derived cancer progression in patients with CN.

Lung microbiome and transcriptome reveal mechanisms underlying PM2.5 induced pulmonary fibrosis

Airborne fine particulate matter (PM_2.5) is considered to be a risk factor for lung fibrosis, and therefore, it has attracted public attention due to its various physicochemical features and its adverse effects on health. However, little remains to be known regarding the mechanism of PM_2.5-induced pulmonary fibrosis. The lung microbiota may be a potential factor involved in the adverse outcomes of pulmonary fibrosis. Meanwhile, miRNAs are thought to be key regulators that participate in the complex interplay between the host and the microbiota. Hence, to investigate the potential mechanisms of pulmonary fibrosis, and to explore the impact of PM_2.5-induced alterations in miRNAs and the lung microbiota and possible interaction patterns in mice models, we took advantage of 16S rDNA gene sequencing, miRNAs sequencing (miRNAs-Seq), and mining of public databases profiling. The results of 16S rDNA analysis showed that PM_2.5 interfered with the microbial community composition, resulting in Proteobacteria becoming an additional dominant phylum. In addition, differentially expressed miRNAs were enriched in HIF-1 signaling, the IL-17 signaling, as well as Th17 cell differentiation pathways, which are closely related to microbial functional pathways. Significantly, a target miRNA, miR-149-5p, may be a key factor triggering the MAPK signal pathway related to pulmonary fibrosis and disturbing the homeostasis of lung bacterial flora. These results indicate that PM_2.5 may lead to interaction between lung microbiota dysbiosis and an imbalance of miRNA levels to form a vicious cycle that promotes lung fibrogenesis. The current study provides new insights into the progression of pulmonary fibrosis.

The Complex Link and Disease Between the Gut Microbiome and the Immune System in Infants

The human gut microbiome is important for human health. The development of stable microbial communities in the gastrointestinal tract is closely related to the early growth and development of host immunity. After the birth of a baby, immune cells and the gut microbiome mature in parallel to adapt to the complex gut environment. The gut microbiome is closely linked to the immune system and influences each other. This interaction is associated with various diseases in infants and young children, such as asthma, food allergies, necrotizing colitis, obesity, and inflammatory bowel disease. Thus, the composition of the infant gut microbiome can predict the risk of disease development and progression. At the same time, the composition of the infant gut microbiome can be regulated in many ways and can be used to prevent and treat disease in infants by modulating the composition of the infant gut microbiome. The most important impacts on infant gut microbiota are maternal, including food delivery and feeding. The differences in the gut microbiota of infants reflect the maternal gut microbiota, which in turn reflects the gut microbiota of a given population, which is clinically significant.

Saliva and Lung Microbiome Associations with Electronic Cigarette Use and Smoking

The microbiome has increasingly been linked to cancer. Little is known about the lung and oral cavity microbiomes in smokers, and even less for electronic cigarette (EC) users, compared with never-smokers. In a cross-sectional study (n = 28) of smokers, EC users, and never-smokers, bronchoalveolar lavage and saliva samples underwent metatranscriptome profiling to examine associations with lung and oral microbiomes. Pairwise comparisons assessed differentially abundant bacteria species. Total bacterial load was similar between groups, with no differences in bacterial diversity across lung microbiomes. In lungs, 44 bacteria species differed significantly (FDR < 0.1) between smokers/never-smokers, with most decreased in smokers. Twelve species differed between smokers/EC users, all decreased in smokers of which Neisseria sp. KEM232 and Curvibacter sp. AEP1-3 were observed. Among the top five decreased species in both comparisons, Neisseria elongata, Neisseria sicca, and Haemophilus parainfluenzae were observed. In the oral microbiome, 152 species were differentially abundant for smokers/never-smokers, and 17 between smokers/electronic cigarette users, but only 21 species were differentially abundant in both the lung and oral cavity. EC use is not associated with changes in the lung microbiome compared with never-smokers, indicating EC toxicity does not affect microbiota. Statistically different bacteria in smokers compared with EC users and never-smokers were almost all decreased, potentially due to toxic effects of cigarette smoke. The low numbers of overlapping oral and lung microbes suggest that the oral microbiome is not a surrogate for analyzing smoking-related effects in the lung.

PREVENTION RELEVANCE

The microbiome affects cancer and other disease risk. The effects of e-cig usage on the lung microbiome are essentially unknown. Given the importance of lung microbiome dysbiosis populated by oral species which have been observed to drive lung cancer progression, it is important to study effects of e-cig use on microbiome.

Impact of Lung Microbiota on COPD

There is a fine balance in maintaining healthy microbiota composition, and its alterations due to genetic, lifestyle, and environmental factors can lead to the onset of respiratory dysfunctions such as chronic obstructive pulmonary disease (COPD). The relationship between lung microbiota and COPD is currently under study. Little is known about the role of the microbiota in patients with stable or exacerbated COPD. Inflammation in COPD disorders appears to be characterised by dysbiosis, reduced lung activity, and an imbalance between the innate and adaptive immune systems. Lung microbiota intervention could ameliorate these disorders. The microbiota’s anti-inflammatory action could be decisive in the onset of pathologies. In this review, we highlight the feedback loop between microbiota dysfunction, immune response, inflammation, and lung damage in relation to COPD status in order to encourage the development of innovative therapeutic goals for the prevention and management of this disease.

Inflammation-associated pulmonary microbiome and metabolome changes in broilers exposed to particulate matter in broiler houses

The particulate matter (PM) in livestock houses, one of the primary sources of atmospheric PM, is not only detrimental to the respiratory health of animals and farmworkers but also poses a threat to the public environment and public health and warrants increased attention. In this study, we investigated the variation in the pulmonary microbiome and metabolome in broiler chickens exposed to PM collected from a broiler house. We examined the pulmonary microbiome and metabolome in broilers, observing that PM induced a visible change in α and β diversity. A total of 66 differential genera, including unclassified_f_Ruminococcaceae and Campylobacter, were associated with pulmonary inflammation. Untargeted metabolomics was utilised to identify 63 differential metabolites induced by PM and correlated with differential bacteria. We observed that PM resulted in injury of the broiler lung and disruption of the microbial community, as well as causing changes in the observed metabolites. These results imply that perturbations to the microbiome and metabolome may play pivotal roles in the mechanism underlying PM-induced broiler lung damage.

Shared and Specific Lung Microbiota with Metabolic Profiles in Bronchoalveolar Lavage Fluid Between Infectious and Inflammatory Respiratory Diseases

Background

Infiltration of the lower respiratory tract (LRT) microenvironment could be significantly associated with respiratory diseases. However, alterations in the LRT microbiome and metabolome in infectious and inflammatory respiratory diseases and their correlation with inflammation still need to be explored.

Methods

Bronchoalveolar lavage samples from 44 community-acquired pneumonia (CAP) patients, 29 connective tissue disease-associated interstitial disease (CTD-ILD) patients, and 30 healthy volunteers were used to detect microbiota and metabolites through 16S rRNA gene sequencing and untargeted high-performance liquid chromatography with mass spectrometry.

Results

The composition of the LRT microbial communities and metabolites differed in disease states. CAP patients showed a significantly low abundance and both diseases presented a depletion of some genera of the phylum Bacteroidetes, including Prevotella, Porphyromonas, and health-associated metabolites, such as sphingosine (d16:1), which were negatively correlated with infectious indicators. In contrast, Bacillus and Mycoplasma were both enriched in the disease groups. Streptococcus was specifically increased in CTD-ILD. In addition, co-elevated metabolites such as FA (22:4) and pyruvic acid represented hypoxia and inflammation in the diseases. Significantly increased levels of amino acids and succinate, as well as decreased itaconic acid levels, were observed in CAP patients, whereas CTD-ILD patients showed only a handful of specific metabolic alterations. Functions related to microbial lipid and amino acid metabolism were significantly altered, indicating the possible contributions of microbial metabolism. Dual omics analysis showed a moderate positive correlation between the microbiome and metabolome. The levels of L-isoleucine and L-arginine were negatively correlated with Streptococcus, and itaconic acid positively correlated with Streptococcus.

Conclusion

In the LRT microenvironment, shared and specific alterations occurred in CAP and CTD-ILD patients, which were associated with inflammatory and immune reactions, which may provide a new direction for future studies aiming to elucidate the mechanism, improve the diagnosis, and develop therapies for different respiratory diseases.

Xuanbai Chengqi Decoction Ameliorates Pulmonary Inflammation via Reshaping Gut Microbiota and Rectifying Th17/Treg Imbalance in a Murine Model of Chronic Obstructive Pulmonary Disease

Purpose

Chronic obstructive pulmonary disease (COPD), a prevalent obstructive airway disease, has become the third most common cause of death globally. Xuanbai Chengqi decoction (XBCQ) is a traditional Chinese medicine prescription for the acute exacerbation of COPD. Here, we aimed to reveal the therapeutic effects of XBCQ administration and its molecular mechanisms mediated by Th17/Treg balance and gut microbiota.

Methods

We determined the counts of Th17 and Treg cells in the serum of 15 COPD and 10 healthy subjects. Then, cigarette smoke extract-induced COPD mice were gavaged with low, middle, and high doses of XBCQ, respectively. Weight loss, pulmonary function and inflammation, Th17/Treg ratio, and gut microbiota were measured to evaluate the efficacy of XBCQ on COPD.

Results

COPD patients had a higher Th17/Treg ratio in the serum than healthy controls, which was consistent with the results in the lung and colon of COPD mice. The middle dose of XBCQ (M-XBCQ) significantly decreased the weight loss and improved the pulmonary function (FEV0.2/FVC) in COPD mice. Moreover, M-XBCQ alleviated lung inflammation by rectifying the Th17/Treg imbalance, reducing the expressions of TNF-α, IL-1β, and MMP-9, and suppressing inflammatory cells infiltration. Meanwhile, M-XBCQ greatly improved the microbial homeostasis in COPD mice by accumulating probiotic Gordonibacter and Akkermansia but inhibiting the growth of pathogenic Streptococcus, which showed significant correlations with pulmonary injury.

Conclusion

Oral M-XBCQ could alleviate COPD exacerbations by reshaping the gut microbiota and improving the Th17/Treg balance, which aids in elucidating the mechanism through which XBCQ as a therapy for COPD.

Inhaled nano-based therapeutics for inflammatory lung diseases: Recent advances and future prospects

Inflammatory lung diseases related morbidity and mortality impose a significant financial burden. Inflammation is a hallmark of many diseases of the respiratory system which is directly or indirectly linked to adverse health conditions, air pollution, rapid lifestyle changes, and regular outbreaks of microbial infections. The unique anatomical and physiological features of the lungs make them an ideal target organ in the treatment of inflammatory respiratory disease and with the help of inhaled therapy lungs can be targeted directly. The principal objective of this review is to present the comprehensive role of inhaled nano-based therapeutics such as liposomes, niosomes, nanoparticles, nanoemulsion, nanosuspension, and exosomes in the treatment and management of inflammatory respiratory diseases. Inhaled nanomedicines provide targeted diagnosis and treatment, improved drug solubility and distribution, prevent first-pass hepatic metabolism, improved patient compliance, and reduced drug side effects. They overcome several biological barriers in the human body and provide immediate, and quick-onset of action. Future research should be focused on improving the therapeutic efficiency of inhaled nanocarriers and to carry out in-depth mechanistic studies to translate current scientific knowledge for the efficient management of inflammatory lung diseases with minimal or no toxicity.

Serum‑derived exosomes from house dust mite‑sensitized guinea pigs contribute to inflammation in BEAS‑2B cells via the TLR4‑NF‑κB pathway

Airway epithelial cells, which are the first physical defense barrier against allergens, play a pivotal role in immunity, airway inflammation and airway remodeling. The damage and dysfunction of these cells trigger the development of airway inflammatory diseases. Exosomes, which exist in various bodily fluids, mediate cell-cell communication and participate in the immune response process. The present study aimed to investigate whether serum exosomes play a pro-inflammatory role in bronchial epithelial cells (BEAS-2B cells) and, if so, explore the underlying molecular mechanisms. A guinea pig model of House dust mite (HDM)-induced asthma was established by sensitizing the rodents with HDM and PBS, and serum-derived exosomes were harvested. It was found that serum-derived exosomes from HDM-sensitized guinea pigs displayed higher levels of exosomal markers than those from controls. Additionally, western blot analysis and reverse transcription-quantitative PCR indicated that serum-derived exosomes from HDM-sensitized guinea pigs carried heat shock protein 70 and triggered an inflammatory response in BEAS-2B cells via the toll-like receptor 4 (TLR4)-NF-κB pathway. However, TAK-242, an inhibitor of the expression of TLR4, blocked the activation of the TLR4-NF-κB pathway. These findings provided a novel mechanism for exosome-mediated inflammatory responses and a new perspective for the intervention of inflammatory airway disorders.

Non-zero-sum microbiome immune system interactions

Fundamental asymmetries between the host and its microbiome in enzymatic activities and nutrient storage capabilities have promoted mutualistic adaptations on both sides. As a result, the enteric immune system has evolved so as not to cause a zero‐sum sterilization of non‐self, but rather achieve a non‐zero‐sum self‐reinforcing cooperation with its evolutionary partner the microbiome. In this review, we attempt to integrate the accumulated knowledge of immune—microbiome interactions into an evolutionary framework and trace the pattern of positive immune—microbiome feedback loops across epithelial, enteric nervous system, innate, and adaptive immune circuits. Indeed, the immune system requires commensal signals for its development and function, and reciprocally protects the microbiome from nutrient shortage and pathogen outgrowth. In turn, a healthy microbiome is the result of immune system curatorship as well as microbial ecology. The paradigms of host–microbiome asymmetry and the cooperative nature of their interactions identified in the gut are applicable across all tissues influenced by microbial activities. Incorporation of immune system influences into models of microbiome ecology will be a step forward toward defining what constitutes a healthy human microbiome and guide discoveries of novel host–microbiome mutualistic adaptations that may be harnessed for the promotion of human health.

Gastrointestinal tissue as a "new" target of pollution exposure

Airborne pollution has become a leading cause of global death in industrialized cities and the exposure to environmental pollutants has been demonstrated to have adverse effects on human health. Among the pollutants, particulate matter (PM) is one of the most toxic and although its exposure has been more commonly correlated with respiratory diseases, gastrointestinal (GI) complications have also been reported as a consequence to PM exposure. Due to its composition, PM is able to exert on intestinal mucosa both direct damaging effects, (by reaching it either via direct ingestion of contaminated food and water or indirect inhalation and consequent macrophagic mucociliary clearance) and indirect ones via generation of systemic inflammation. The relationship between respiratory and GI conditions is well described by the lung-gut axis and more recently, has become even clearer during coronavirus disease 2019 (COVID-19) pandemic, when respiratory symptoms were associated with gastrointestinal conditions. This review aims at pointing out the mechanisms and the models used to evaluate PM induced GI tract damage.

Mucus, Microbiomes and Pulmonary Disease

The respiratory tract harbors a stable and diverse microbial population within an extracellular mucus layer. Mucus provides a formidable defense against infection and maintaining healthy mucus is essential to normal pulmonary physiology, promoting immune tolerance and facilitating a healthy, commensal lung microbiome that can be altered in association with chronic respiratory disease. How one maintains a specialized (healthy) microbiome that resists significant fluctuation remains unknown, although smoking, diet, antimicrobial therapy, and infection have all been observed to influence microbial lung homeostasis. In this review, we outline the specific role of polymerizing mucin, a key functional component of the mucus layer that changes during pulmonary disease. We discuss strategies by which mucin feed and spatial orientation directly influence microbial behavior and highlight how a compromised mucus layer gives rise to inflammation and microbial dysbiosis. This emerging field of respiratory research provides fresh opportunities to examine mucus, and its function as predictors of infection risk or disease progression and severity across a range of chronic pulmonary disease states and consider new perspectives in the development of mucolytic treatments.

Dysbiosis revisited: Understanding the role of the oral microbiome in the pathogenesis of gingivitis and periodontitis: A critical assessment

This commentary provides background, historical context, and a critical assessment of the concept that microbial dysbiosis drives the pathogenesis of periodontal diseases. It is long known that periodontal pathogenesis is dependent on tooth-borne microbial biofilms (dental plaque) that trigger host inflammation resulting in periodontal destruction and tooth loss in some patients. Ecological principles governing plaque biofilm development, along with localized host responses, are both rooted in evolution. Interpretation of available evidence suggests that, in most patients, alveolar bone loss results from interactions of a highly diverse commensal microbiota with the host, and not from "overgrowth" of a few "pathobionts" that results in a "dysbiosis." Most previously described dysbiotic chronic diseases, for example, inflammatory bowel diseases and dermatitis, are characterized by decreased microbial diversity (likely due to frank overgrowth of one or a few microbial taxa). Most common forms of periodontitis do not appear to conform to this general principle, and the associated microbiome in fact almost always shows increased bacterial diversity compared with periodontal health. This diversity is driven by interactions of genetic and environmental factors working in concert within specific windows of time. Periodontal pathogenesis is likely the result of "personalized pathology," insofar as each patient likely has a variable constellation of microbes and host risk factors influencing specific tissue sites where disease activity occurs, and during a limited window of time (a tissue-destructive "burst"). The concept of cooperative virulence of higher abundance commensals in periodontal pathogenesis, which does not conform to the model of dysbiosis observed for other diseases, is discussed.

Spontaneous regression of incidentally diagnosed bronchial squamous cell lung carcinoma after severe bronchitis: A case report

Spontaneous regression of lung cancer is exceptionally rare. But there have been several intriguing cases reported in early and even advanced stages of lung cancer. Although the exact mechanism remains to be elucidated, the inflammation and immunologic response have been suggested as one of the means of spontaneous regression. Chronic inflammation is generally known to induce and aggravate tumorigenesis, but the relationship between cancer and inflammation highly depends on the contexts. Here, we present a case of a 60-year-old male ex-smoker who complained of recurrent hemoptysis, cough, and purulent sputum. The initial chest CT scan revealed diffuse bronchial thickening and an endobronchial mass-like lesion in the left lingular segment. The bronchoscopic and pathological findings also suggested a diagnosis of squamous cell carcinoma with severe mucosal inflammation. He was treated with antibiotics for the bronchitis during the first 1 week and his symptoms markedly improved. After 3 weeks, he underwent a follow-up examination. Chest computed tomography and bronchoscopy revealed the significant improvement of the bronchial narrowing and mucosal edema. Biopsy was performed several times around the lesion where the tissue was initially taken. However, the pathological results showed only chronic inflammation of bronchi, not cancer cells. Fortunately, there was no recurrence of lung cancer in follow-up chest computed tomography or bronchoscopy for almost 5 years. In this case, the incidentally diagnosed bronchial squamous cell carcinoma disappeared after severe inflammatory reaction of the bronchial wall. The clinician should remind the risk of early lung cancer accompanied with bronchitis in high-risk patients of lung cancer and also be aware that although it is very rare, the lesions could spontaneously regress.

Every breath you take: Impacts of environmental dust exposure on intestinal barrier function-from the gut-lung axis to COVID-19

As countries continue to industrialize, major cities experience diminished air quality, whereas rural populations also experience poor air quality from sources such as agricultural operations. These exposures to environmental pollution from both rural and populated/industrialized sources have adverse effects on human health. Although respiratory diseases (e.g., asthma and chronic obstructive pulmonary disease) are the most commonly reported following long-term exposure to particulate matter and hazardous chemicals, gastrointestinal complications have also been associated with the increased risk of lung disease from inhalation of polluted air. The interconnectedness of these organ systems has offered valuable insights into the roles of the immune system and the micro/mycobiota as mediators of communication between the lung and the gut during disease states. A topical example of this relationship is provided by reports of multiple gastrointestinal symptoms in patients with coronavirus disease 2019 (COVID-19), whereas the rapid transmission and increased risk of COVID-19 has been linked to poor air quality and high levels of particulate matter. In this review, we focus on the mechanistic effects of environmental pollution on disease progression with special emphasis on the gut-lung axis.

Functional profiling of COVID-19 respiratory tract microbiomes

In response to the ongoing global pandemic, characterizing the molecular-level host interactions of the new coronavirus SARS-CoV-2 responsible for COVID-19 has been at the center of unprecedented scientific focus. However, when the virus enters the body it also interacts with the micro-organisms already inhabiting the host. Understanding the virus-host-microbiome interactions can yield additional insights into the biological processes perturbed by viral invasion. Alterations in the gut microbiome species and metabolites have been noted during respiratory viral infections, possibly impacting the lungs via gut-lung microbiome crosstalk. To better characterize microbial functions in the lower respiratory tract during COVID-19 infection, we carry out a functional analysis of previously published metatranscriptome sequencing data of bronchoalveolar lavage fluid from eight COVID-19 cases, twenty-five community-acquired pneumonia patients, and twenty healthy controls. The functional profiles resulting from comparing the sequences against annotated microbial protein domains clearly separate the cohorts. By examining the associated metabolic pathways, distinguishing functional signatures in COVID-19 respiratory tract microbiomes are identified, including decreased potential for lipid metabolism and glycan biosynthesis and metabolism pathways, and increased potential for carbohydrate metabolism pathways. The results include overlap between previous studies on COVID-19 microbiomes, including decrease in the glycosaminoglycan degradation pathway and increase in carbohydrate metabolism. The results also suggest novel connections to consider, possibly specific to the lower respiratory tract microbiome, calling for further research on microbial functions and host-microbiome interactions during SARS-CoV-2 infection.

New Insights Into the Physiopathology of COVID-19: SARS-CoV-2-Associated Gastrointestinal Illness

Although SARS-CoV-2 is considered a lung-tropic virus that infects the respiratory tract through binding to the ACE2 cell-surface molecules present on alveolar lungs epithelial cells, gastrointestinal symptoms have been frequently reported in COVID-19 patients. What can be considered an apparent paradox is that these symptoms (e.g., diarrhea), sometimes precede the development of respiratory tract illness as if the breathing apparatus was not its first target during viral dissemination. Recently, evidence was reported that the gut is an active site of replication for SARS-CoV-2. This replication mainly occurs in mature enterocytes expressing the ACE2 viral receptor and TMPRSS4 protease. In this review we question how SARS-CoV-2 can cause intestinal disturbances, whether there are pneumocyte-tropic, enterocyte-tropic and/or dual tropic strains of SARS-CoV-2. We examine two major models: first, that of a virus directly causing damage locally (e.g., by inducing apoptosis of infected enterocytes); secondly, that of indirect effect of the virus (e.g., by inducing changes in the composition of the gut microbiota followed by the induction of an inflammatory process), and suggest that both situations probably occur simultaneously in COVID-19 patients. We eventually discuss the consequences of the virus replication in brush border of intestine on long-distance damages affecting other tissues/organs, particularly lungs.

Breath Biopsy and Discovery of Exclusive Volatile Organic Compounds for Diagnosis of Infectious Diseases

Exhaled breath contains thousand metabolites and volatile organic compounds (VOCs) that originated from both respiratory tract and internal organ systems and their microbiomes. Commensal and pathogenic bacteria and virus of microbiomes are capable of producing VOCs of different chemical classes, and some of them may serve as biomarkers for installation and progression of various common human diseases. Here we describe qualitative and quantitative methods for measuring VOC fingerprints generated by cellular and microbial metabolic and pathologic pathways. We describe different chemical classes of VOCs and their role in the host cell-microbial interactions and their impact on infection disease pathology. We also update on recent progress on VOC signatures emitted by isolated bacterial species and microbiomes, and VOCs identified in exhaled breath of patients with respiratory tract and gastrointestinal diseases, and inflammatory syndromes, including the acute respiratory distress syndrome and sepsis. The VOC curated databases and instrumentations have been developed through statistically robust breathomic research in large patient populations. Scientists have now the opportunity to find potential biomarkers for both triage and diagnosis of particular human disease.

Chronic obstructive pulmonary disease in HIV

Introduction: Chronic obstructive pulmonary disease (COPD) is more prevalent in people with HIV (PWH) than in the general population and leads to an increased burden of morbidity and mortality in this population. The mechanisms behind COPD development and progression in PWH are not fully elucidated, and there are no PWH-specific guidelines for COPD management. Areas covered: The goal of this broad narrative review is to review the epidemiology of COPD in PWH globally, highlight proposed pathways contributing to increased COPD prevalence and progression in PWH, discuss structural and functional changes in the lungs in this population, assesses the excess mortality and comorbidities in PWH with COPD, and address management practices for this unique population. Expert opinion: Understanding how a chronic viral infection leads to COPD, independent of cigarette smoking, is of critical scientific importance. Further research should focus on the pathophysiology of the interaction between HIV and COPD, and determine the role of disease-modifying risk factors such as opportunistic pneumonia and air pollution, as well as generate data from randomized clinical trials on the safety and efficacy of specific therapies for this vulnerable patient population.

The Lung Microbiome: A Central Mediator of Host Inflammation and Metabolism in Lung Cancer Patients?

Simple Summary

Lung cancer is the major cause of cancer related deaths in the world. New therapies have improved outcomes. Unfortunately, overall 5 year survival is ~20%. Therefore, better understanding of tumor biology and the microenvironment may lead to new therapeutic targets. The lung microbiome has recently emerged as a major mediator of host inflammation and pathogenesis. Understanding how the lung microbiota exerts its effects on lung cancer and the tumor microenvironment will allow for novel development of therapies.

Abstract

Lung cancer is the leading cause of cancer-related death. Over the past 5–10 years lung cancer outcomes have significantly improved in part due to better treatment options including immunotherapy and molecularly targeted agents. Unfortunately, the majority of lung cancer patients do not enjoy durable responses to these new treatments. Seminal research demonstrated the importance of the gut microbiome in dictating responses to immunotherapy in melanoma patients. However, little is known regarding how other sites of microbiota in the human body affect tumorigenesis and treatment responses. The lungs were traditionally thought to be a sterile environment; however, recent research demonstrated that the lung contains its own dynamic microbiota that can influence disease and pathophysiology. Few studies have explored the role of the lung microbiome in lung cancer biology. In this review article, we discuss the links between the lung microbiota and cancer, with particular focus on immune responses, metabolism and strategies to target the lung microbiome for cancer prevention.

A new phenolic glycoside from Trollius chinensis Bunge with anti-inflammatory and antibacterial activities

A undescribed phenolic glycoside, trochinenol A (1), was isolated from the flowers of Trollius chinensis Bunge and the structure was identified by spectroscopic methods. Its anti-inflammatory and antibacterial effects were investigated by broth microdilution and NF-κB reporter gene assays. Consequently, compound 1 exhibited an appreciable effect against Staphylococcus aureus with the MIC value of 6.25 µg/mL. Besides, it showed moderate effect against TNFα-induced activation of NF-κB pathway.

The Protective Effects of Helicobacter pylori Infection on Allergic Asthma

As an ancient Gram-negative bacterium, Helicobacter pylori has settled in human stomach. Eradicating H. pylori increases the morbidities of asthma and other allergic diseases. Therefore, H. pylori might play a protective role against asthma. The "disappearing microbiota" hypothesis suggests that the absence of certain types of the ancestral microbiota could change the development of immunology, metabolism, and cognitive ability in our early life, contributing to the development of some diseases. And the Hygiene Hypothesis links early environmental and microbial exposure to the prevalence of atopic allergies and asthma. Exposure to the environment and microbes can influence the growing immune system and protect subsequent immune-mediated diseases. H. pylori can inhibit allergic asthma by regulating the ratio of helper T cells 1/2 (Th1/Th2), Th17/regulatory T cells (Tregs), etc. H. pylori can also target dendritic cells to promote immune tolerance and enhance the protective effect on allergic asthma, and this effect relies on highly suppressed Tregs. The remote regulation of lung immune function by H. pylori is consistent with the gut-lung axis theory. Perhaps, H. pylori also protects against asthma by altering levels of stomach hormones, affecting the autonomic nervous system and lowering the expression of heat shock protein 70. Therapeutic products from H. pylori may be used to prevent and treat asthma. This paper reviews the possible protective influence of H. pylori on allergic asthma and the possible application of H. pylori in treating asthma.

Microbiota and Lung Cancer. Opportunities and Challenges for Improving Immunotherapy Efficacy

The advances in molecular biology and the emergence of Next Generation Sequencing (NGS) have revealed that microbiome composition is closely related with health and disease, including cancer. This relationship affects different levels of cancer such as development, progression, and response to treatment including immunotherapy. The efficacy of immune checkpoint inhibitors (ICIs) may be influenced by the concomitant use of antibiotics before, during or shortly after treatment with ICIs. Nevertheless, the linking mechanism between microbiote, host immunity and cancer is not clear and the role of microbiota manipulation and analyses in cancer management has not been clinically validated yet. Regarding the use of microbiome as biomarker to predict ICI efficacy it has been recently shown that the use of biochemical serum markers to monitor intestinal permeability and loss of barrier integrity, like citrulline, could be useful to monitor microbiota changes and predict ICI efficacy. There are still many unknowns about the role of these components, their relationship with the microbiota, with the use of antibiotics and the response to immunotherapy. The next challenge in microbiome research will be to identify individual microbial species that causally affect lung cancer phenotypes and response to ICI and disentangle the underlying mechanisms. Thus, further analyses in patients with lung cancer receiving treatment with ICIs and its correlation with the composition of the microbiota in different organs including the respiratory tract, peripheral blood and intestinal tract could be useful to predict the efficacy of ICIs and its modulation with antibiotic use.

Role of Lung Microbiome in Innate Immune Response Associated With Chronic Lung Diseases

Respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), lung fibrosis, and lung cancer, pose a huge socio-economic burden on society and are one of the leading causes of death worldwide. In the past, culture-dependent techniques could not detect bacteria in the lungs, therefore the lungs were considered a sterile environment. However, the development of culture-independent techniques, particularly 16S rRNA sequencing, allowed for the detection of commensal microbes in the lung and with further investigation, their roles in disease have since emerged. In healthy individuals, the predominant commensal microbes are of phylum Firmicutes and Bacteroidetes, including those of the genera Veillonella and Prevotella. In contrast, pathogenic microbes (Haemophilus, Streptococcus, Klebsiella, Pseudomonas) are often associated with lung diseases. There is growing evidence that microbial metabolites, structural components, and toxins from pathogenic and opportunistic bacteria have the capacity to stimulate both innate and adaptive immune responses, and therefore can contribute to the pathogenesis of lung diseases. Here we review the multiple mechanisms that are altered by pathogenic microbiomes in asthma, COPD, lung cancer, and lung fibrosis. Furthermore, we focus on the recent exciting advancements in therapies that can be used to restore altered microbiomes in the lungs.

Multi-Omics Approaches: The Key to Improving Respiratory Health in People With Cystic Fibrosis?

The advent of high-throughput multi-omics technologies has underpinned the expansion in lung microbiome research, increasing our understanding of the nature, complexity and significance of the polymicrobial communities harbored by people with CF (PWCF). Having established that structurally complex microbial communities exist within the airways, the focus of recent research has now widened to investigating the function and dynamics of the resident microbiota during disease as well as in health. With further refinement, multi-omics approaches present the opportunity to untangle the complex interplay between microbe-microbe and microbe-host interactions in the lung and the relationship with respiratory disease progression, offering invaluable opportunities to discover new therapeutic approaches for our management of airway infection in CF.

Persistent Legionnaires' Disease and Associated Antibiotic Treatment Engender a Highly Disturbed Pulmonary Microbiome Enriched in Opportunistic Microorganisms

Despite the importance of pneumonia to public health, little is known about the composition of the lung microbiome during infectious diseases, such as pneumonia, and how it evolves during antibiotic therapy. To study the possible relation of the pulmonary microbiome to the severity and outcome of this respiratory disease, we analyzed the dynamics of the pathogen and the human lung microbiome during persistent infections caused by the bacterium Legionella pneumophila and their evolution during antimicrobial treatment. We collected 10 bronchoalveolar lavage fluid samples from three patients during long-term hospitalization due to pneumonia and performed a unique longitudinal study of the interkingdom microbiome, analyzing the samples for presence of bacteria, archaea, fungi, and protozoa by high-throughput Illumina sequencing of marker genes. The lung microbiome of the patients was characterized by a strong predominance of the pathogen, a low diversity of the bacterial fraction, and an increased presence of opportunistic microorganisms. The fungal fraction was more stable than the bacterial fraction. During long-term treatment, no genomic changes or antibiotic resistance-associated mutations that could explain the persistent infection occurred, according to whole-genome sequencing analyses of the pathogen. After antibiotic treatment, the microbiome did not recover rapidly but was mainly constituted of antibiotic-resistant species and enriched in bacteria, archaea, fungi, or protozoa associated with pathogenicity. The lung microbiome seems to contribute to nonresolving Legionella pneumonia, as it is strongly disturbed during infection and enriched in opportunistic and/or antibiotic-resistant bacteria and microorganisms, including fungi, archaea, and protozoa that are often associated with infections.IMPORTANCE The composition and dynamics of the lung microbiome during pneumonia are not known, although the lung microbiome might influence the severity and outcome of this infectious disease, similar to what was shown for the microbiome at other body sites. Here we report the findings of a comprehensive analysis of the lung microbiome composition of three patients with long-term pneumonia due to L. pneumophila and its evolution during antibiotic treatment. This work adds to our understanding of how the microbiome changes during disease and antibiotic treatment and points to microorganisms and their interactions that might be beneficial. In addition to bacteria and fungi, our analyses included archaea and eukaryotes (protozoa), showing that both are present in the pulmonary microbiota and that they might also play a role in the response to the microbiome disturbance.

The Cross-Talk Between Gut Microbiota and Lungs in Common Lung Diseases

Emerging findings indicate there is a vital cross-talk between gut microbiota and the lungs, which is known as gut-lung axis. The gut disturbances in lung diseases including allergy, asthma, chronic obstructive pulmonary disease, cystic fibrosis and lung cancer were observed by extensive studies. Investigating how gut microbiota impact other distant organs is of great interest in recent years. Although it has not been fully understood whether the disturbance is the cause or effect of lung diseases, alterations in the gut microbial species and metabolites have been linked to changes in immune responses and inflammation as well as the disease development in the lungs. In this article, we systemically review the role and mechanisms underlying the changes in the constituent of gut microbiota and metabolites in lung diseases. In particular, the roles of gut-lung axis in mediating immune responses and reshaping inflammation are highlighted. Furthermore, we discuss the potential of strategies to manipulate the gut microbiota and metabolites as the therapeutic approach for lung diseases.

Does exposure to inflammatory particles modify the pattern of anion in exhaled breath condensate?

Exposure to environmental and occupational particulate matter (PM) induces health effects on the cardio-pulmonary system. In addition, associations between exposure to PM and metabolic syndromes like diabetes mellitus or obesity are now emerging in the literature. Collection of exhaled breath condensate (EBC) is an appealing non-invasive technique to sample pulmonary fluids. This hypothesis-generating study aims to (1) validate an ion chromatography method allowing the robust determination of different metabolism-related molecules (lactate, formate, acetate, propionate, butyrate, pyruvate, nitrite, nitrate) in EBC; (2) apply this method to EBC samples collected from workers exposed to quartz (a known inflammatory particle), to soapstone (a less inflammatory particle than quartz), as well as to controls. A multi-compound standard solution was used to determine the linearity range, detection limit, repeatability and bias from spiked EBC. The biological samples were injected without further treatment into an ion chromatograph with a conductivity detector. RTube^® were used for field collection of EBC from 11 controls, 55 workers exposed to soapstone and 12 volunteers exposed to quartz dust. The analytical method used proved to be adequate for quantifying eight anions in EBC samples. Its sub-micromolar detection limits and repeatability, combined with a very simple sample preparation, allowed an easy and fast quantification of different glycolysis or nitrosative stress metabolites. Using multivariate discriminant analysis to maximize differences between groups, we observed a different pattern of anions with a higher formate/acetate ratio in the EBC samples for quartz exposed workers compared to the two other groups. We hypothesize that a modification of the metabolic signature could be induced by exposure to inflammatory particles like quartz and might be observed in the EBC via a change in the formate/acetate ratio.

Regulation of lung endothelial permeability by NEK kinases

Dysregulation of lung endothelial barrier function may lead to lethal outcomes, as demonstrated in the case of the acute respiratory distress syndrome (ARDS). p53 participates in the regulation of the lung endothelial barrier, and it has been associated both in vivo and in vitro with protective effects against the LPS-induced hyperpermeability. Family members of the never in mitosis A-related kinases (NEKs) are crucial mediators of fundamental cellular processes, including mitosis, and have been shown to posttranslationally modify p53. Since such modifications affect p53 stability and activity, it is highly probable that NEK kinases are also regulators of lung endothelial permeability. Thus, they may serve as possible therapeutic targets for treatment of pathologies associated with endothelial barrier dysfunction.

Perspectives on Probiotics and Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic respiratory disease of preterm infants, associated with high morbidity and hospitalization expenses. With the revolutionary advances in microbiological analysis technology, increasing evidence indicates that children with BPD are affected by lung microbiota dysbiosis, which may be related to the illness occurrence and progression. However, dysbiosis treatment in BPD patients has not been fully investigated. Probiotics are living microorganisms known to improve human health for their anti-inflammatory and anti-tumor effects, and particularly by balancing gut microbiota composition, which promotes gut-lung axis recovery. The aim of the present review is to examine current evidence of lung microbiota dysbiosis and explore potential applications of probiotics in BPD, which may provide new insights into treatment strategies of this disease.

Vancomycin-induced gut dysbiosis during Pseudomonas aeruginosa pulmonary infection in a mice model

Pseudomonas aeruginosa is one of the most common opportunistic pathogens causing respiratory infections in hospitals. Vancomycin, the antimicrobial agent usually used to treat bacterial nosocomial infections, is associated with gut dysbiosis. As a lung-gut immunologic axis has been described, this study aimed to evaluate both the immunologic and histopathologic effects on the lungs and the large intestine resulting from vancomycin-induced gut dysbiosis in the P. aeruginosa pneumonia murine model. Metagenomic analysis demonstrated that vancomycin-induced gut dysbiosis resulted in higher Proteobacteria and lower Bacteroidetes populations in feces. Given that gut dysbiosis could augment the proinflammatory status of the intestines leading to a variety of acute inflammatory diseases, bone marrow-derived macrophages were stimulated with cecal content from dysbiotic mice showing a higher expression of proinflammatory cytokines and lower expression of IL-10. Dysbiotic mice showed higher levels of viable bacteria in the lungs and spleen when acutely infected with P. aeruginosa, with more lung and cecal damage and increased IL-10 expression in bronchoalveolar lavage. The susceptible and tissue damage phenotype was reversed when dysbiotic mice received fecal microbiota transplantation. In spite of higher recruitment of CD11b+ cells in the lungs, there was no higher CD80+ expression, DC+ cell amounts or proinflammatory cytokine expression. Taken together, our results indicate that the bacterial community found in vancomycin-induced dysbiosis dysregulates the gut inflammatory status, influencing the lung-gut immunologic axis to favor increased opportunistic infections, for example, by P. aeruginosa.