Increased risk of both ulcerative colitis and Crohn's disease in a population suffering from COPD

Pulmonary Manifestations of IBD: Case Report and Review of the Literature

This article explores the pulmonary complications associated with inflammatory bowel disease (IBD). It presents a detailed case study of a 22-year-old male with Crohn's disease exhibiting pulmonary symptoms. The review delves into the spectrum of pulmonary involvement in IBD, covering clinical presentations, diagnostic challenges, underlying pathophysiology, and management strategies. It highlights the significance of these extraintestinal manifestations on patient outcomes and quality of life. The article underscores the need for heightened clinical awareness and a systematic approach to diagnosis and management, integrating the expertise of multiple specialists. The review identifies gaps in current research, suggesting avenues for future investigation to enhance the understanding and treatment of these complex manifestations.

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.

Autoimmune diseases and COPD risk: A Mendelian randomization study

BACKGROUND

Studies in epidemiology have indicated a link between chronic obstructive pulmonary disease (COPD) and various autoimmune conditions.This study aimed to investigate the potential causal link between nine autoimmune diseases with a genetic basis and COPD using a two-sample Mendelian randomization (MR) analysis.

METHOD

To test the impact of susceptibility to immune-related outcomes on genetic prediction of COPD risk, we used pooled statistics from the largest genome-wide association study (GWAS) in Europe in a two-sample MR setting.Genetic data for type 1 diabetes, hypothyroidism, systemic lupus erythematosus, and primary biliary cirrhosis were obtained from the European Bioinformatics Institute (EBI), while data for multiple sclerosis and primary sclerosing cholangitis were extracted from the Integrative Epidemiology Unit (IEU) database. Additionally, genetic data for ulcerative colitis, rheumatoid arthritis, and celiac disease were also collected.These nine autoimmune diseases and the COPD cohort from the UK Biobank (1605 cases and 461,328 controls) were analyzed separately as exposure and outcome.Our primary method for the initial screening was inverse variance weighting (IVW).The MR-Egger regression test assessed multivariate validity, while the Cochran's Q test examined heterogeneity.To ensure the reliability of the findings, a leave-one-out analysis was conducted.

RESULT

IVW discovered proof of type 1 diabetes (OR = 1.0003; 95 % CI = 1.0000-1.0005; P = 0.046), hypothyroidism (OR = 1.0004; 95 % CI = 1.0001-1.0008; P = 0.0263), celiac disease (OR = 1.0002; 95 % CI = 1.0000-1.0004; P = 0.0168) and systemic lupus erythematosus (OR = 1.0002; 95 % CI = 1.0000-1.0004; P = 0.049) were significantly linked to the heightened risk of COPD with no signs of variation or pleiotropy.Even after accounting for potential confounding factors like smoking, the correlation remained robust.Additionally, our research found that the IVW method did not indicate any causal link between COPD and multiple sclerosis, ulcerative colitis, rheumatoid arthritis, primary biliary cirrhosis, or primary sclerosing cholangitis (all P >0.05).

CONCLUSION

This research discovered that individuals with type 1 diabetes, hypothyroidism, celiac disease, and systemic lupus erythematosus have a higher likelihood of developing COPD.Additionally, this research revealed no connection between COPD and multiple sclerosis, ulcerative colitis, rheumatoid arthritis, primary biliary cirrhosis, or primary sclerosing cholangitis.

Respiratory diseases and gut microbiota: relevance, pathogenesis, and treatment

Preclinical evidence has firmly established a bidirectional interaction among the lung, gut, and gut microbiome. There are many complex communication pathways between the lung and intestine, which affect each other's balance. Some metabolites produced by intestinal microorganisms, intestinal immune cells, and immune factors enter lung tissue through blood circulation and participate in lung immune function. Altered gut-lung-microbiome interactions have been identified in rodent models and humans of several lung diseases such as pulmonary fibrosis, chronic obstructive pulmonary disease, lung cancer, asthma, etc. Emerging evidence suggests that microbial therapies can prevent and treat respiratory diseases, but it is unclear whether this association is a simple correlation with the pathological mechanisms of the disease or the result of causation. In this review, we summarize the complex and critical link between the gut microbiota and the lung, as well as the influence and mechanism of the gut microbiota on respiratory diseases, and discuss the role of interventions such as prebiotics and fecal bacteria transplantation on respiratory diseases. To provide a reference for the rational design of large-scale clinical studies, the direct application of microbial therapy to respiratory-related diseases can reduce the incidence and severity of diseases and accompanying complications.

The role of gut-lung axis in COPD: Pathogenesis, immune response, and prospective treatment

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and healthcare burden worldwide. The progression of COPD is a combination of genetic predisposition and environmental factors, primarily cigarette smoking, and the underlying mechanisms are still unknown. Intestinal microecology impacts host immunity, metabolism, and resistance to pathogenic infections, which may be involved in pulmonary disease. Moreover, substantial interaction occurs between the intestinal and respiratory immune niches. After reviewing nearly 500 articles, we found the gut-lung axis plays an important role in the development of COPD. COPD patients often have dysbiosis of the intestinal microenvironment, which can affect host immunity through a series of mechanisms, exacerbating or protecting against COPD progression. This paper summarizes how the gut-lung axis influences COPD, including the alterations of intestinal microecology, the pathological mechanisms, and the involved immune responses. Finally, we summarize the latest research advances in COPD treatment from the perspective of regulating the gut-lung axis and intestinal immunity and evaluate the potential value of the gut-lung axis in improving COPD prognosis.

Long-Term Erythromycin Treatment Alters the Airway and Gut Microbiota: Data from Chronic Obstructive Pulmonary Disease Patients and Mice with Emphysema

INTRODUCTION

Although long-term macrolide antibiotics could reduce the recurrent exacerbation of chronic obstructive pulmonary disease (COPD), the side effect of bacterial resistance and the impact on the microbiota remain concerning. We investigated the influence of long-term erythromycin treatment on the airway and gut microbiota in mice with emphysema and patients with COPD.

METHODS

We conducted 16S rRNA gene sequencing to explore the effect of erythromycin treatment on the lung and gut microbiota in mice with emphysema. Liquid chromatography-mass spectrometry was used for lung metabolomics. A randomized controlled trial was performed to investigate the effect of 48-week erythromycin treatment on the airway and gut microbiota in COPD patients.

RESULTS

The mouse lung and gut microbiota were disrupted after cigarette smoke exposure. Erythromycin treatment depleted harmful bacteria and altered lung metabolism. Erythromycin treatment did not alter airway or gut microbial diversity in COPD patients. It reduced the abundance of pathogens, such as Burkholderia, in the airway of COPD patients and increased levels of symbiotic bacteria, such as Prevotella and Veillonella. The proportions of Blautia, Ruminococcus, and Lachnospiraceae in the gut were increased in COPD patients after erythromycin treatment. The time to the first exacerbation following treatment was significantly longer in the erythromycin treatment group than in the COPD group.

CONCLUSION

Long-term erythromycin treatment reduces airway and gut microbe abundance in COPD patients but does not affect microbial diversity and restores microbiota balance in COPD patients by reducing the abundance of pathogenic bacteria.

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.

Genetic Insights into the Gut-Lung Axis: Mendelian Randomization Analysis on Gut Microbiota, Lung Function, and COPD

Background

Chronic obstructive pulmonary disease (COPD) is a respiratory disorder with a complex etiology involving genetic and environmental factors. The dysbiosis of gut microbiota has been implicated in COPD. Mendelian Randomization (MR) provides a tool to investigate causal links using genetic variants as instrumental variables. This study aims to employ MR analysis to explore the causal relationship between gut microbiota, lung function, and COPD.

Methods

We utilized genome-wide association study (GWAS) data from MiBioGen, UK Biobank and FinnGen, which were related to gut microbial taxa, lung function parameters including forced vital capacity in one second (FEV1), forced vital capacity (FVC), and percentage of predicted FEV1 (FEV1%pred), as well as GWAS data for COPD. MR analysis was conducted to assess the causal effects of gut microbiota on lung function and the risk of COPD. Sensitivity analysis was utilized to examine the stability of the causal relationships. Multiple testing and reverse analysis were employed to evaluate the robustness of these relationships.

Results

Using the IVW method, 64 causal correlations were identified. Through conducting sensitivity analysis, multiple testing, and reverse analysis, we identified 14 robust and stable causal relationships. The bacterial taxa that showed a positive association with lung function included Desulfovibrionaceae, Erysipelotrichales, Desulfovibrionales, Clostridiales, Clostridia, Deltaproteobacteria and Erysipelotrichia, while Selenomonadales and Negativicutes showed a negative association with lung function. The abundance of Holdemanella were positively correlated with the risk of COPD, while FamilyXIII exhibited a negative correlation with the risk of COPD.

Conclusion

Several microbial taxa were discovered to have a positive causal correlation with lung function, offering potential insights into the development of probiotics. The presence of microbial taxa negatively correlated with lung function and positively correlated with COPD emphasized the potential impact of gut microbiota dysbiosis on respiratory health.

Immune regulation of the gut-brain axis and lung-brain axis involved in ischemic stroke

Local ischemia often causes a series of inflammatory reactions when both brain immune cells and the peripheral immune response are activated. In the human body, the gut and lung are regarded as the key reactional targets that are initiated by brain ischemic attacks. Mucosal microorganisms play an important role in immune regulation and metabolism and affect blood-brain barrier permeability. In addition to the relationship between peripheral organs and central areas and the intestine and lung also interact among each other. Here, we review the molecular and cellular immune mechanisms involved in the pathways of inflammation across the gut-brain axis and lung-brain axis. We found that abnormal intestinal flora, the intestinal microenvironment, lung infection, chronic diseases, and mechanical ventilation can worsen the outcome of ischemic stroke. This review also introduces the influence of the brain on the gut and lungs after stroke, highlighting the bidirectional feedback effect among the gut, lungs, and brain.

Systemic antibiotics cause deterioration of emphysema associated with exaggerated inflammation and autophagy

The interaction between the microbial environment and the host is important for immune homeostasis. Recent research suggests that microbiota dysbiosis can be involved in respiratory diseases. Emphysema is a chronic inflammatory disease, but it is unclear whether dysbiosis caused by antibiotics can affect disease progression. Here, we tried to elucidate the effect of systemic antibiotics on smoking-exposed emphysema models. In this study, the antibiotic mixture caused more alveolar destruction and airspace expansion in the smoking group than in the smoking only or control groups. This emphysema aggravation as a result of antibiotic exposure was associated with increased levels of inflammatory cells, IL-6, IFNγ and protein concentrations in bronchoalveolar lavage fluid. Proteomics analysis indicated that autophagy could be involved in antibiotic-associated emphysema aggravation, and increased protein levels of LC3B, atg3, and atg7 were identified by Western blotting. In microbiome and metabolome analyses, the composition of the gut microbiota was different with smoking and antibiotic exposure, and the levels of short-chain fatty acids (SCFAs), including acetate and propionate, were reduced by antibiotic exposure. SCFA administration restored emphysema development with reduced inflammatory cells, IL-6, and IFNγ and decreased LC3B, atg3, and atg7 levels. In conclusion, antibiotics can aggravate emphysema, and inflammation and autophagy may be associated with this aggravation. This study provides important insight into the systemic impact of microbial dysbiosis and the therapeutic potential of utilizing the gut microbiota in emphysema.

The lung-gut crosstalk in respiratory and inflammatory bowel disease

Both lung and gut belong to the common mucosal immune system (CMIS), with huge surface areas exposed to the external environment. They are the main defense organs against the invasion of pathogens and play a key role in innate and adaptive immunity. Recently, more and more evidence showed that stimulation of one organ can affect the other, as exemplified by intestinal complications during respiratory disease and vice versa, which is called lung-gut crosstalk. Intestinal microbiota plays an important role in respiratory and intestinal diseases. It is known that intestinal microbial imbalance is related to inflammatory bowel disease (IBD), this imbalance could impact the integrity of the intestinal epithelial barrier and leads to the persistence of inflammation, however, gut microbial disturbances have also been observed in respiratory diseases such as asthma, allergy, chronic obstructive pulmonary disease (COPD), and respiratory infection. It is not fully clarified how these disorders happened. In this review, we summarized the latest examples and possible mechanisms of lung-gut crosstalk in respiratory disease and IBD and discussed the strategy of shaping intestinal flora to treat respiratory diseases.

Omega-3 Polyunsaturated Fatty Acids in Managing Comorbid Mood Disorders in Chronic Obstructive Pulmonary Disease (COPD): A Review

Chronic obstructive pulmonary disease (COPD) is the third-leading cause of mortality globally, significantly affecting people over 40 years old. COPD is often comorbid with mood disorders; however, they are frequently neglected or undiagnosed in COPD management, thus resulting in unintended treatment outcomes and higher mortality associated with the disease. Although the exact link between COPD and mood disorders remains to be ascertained, there is a broader opinion that inflammatory reactions in the lungs, blood, and inflammation-induced changes in the brain could orchestrate the onset of mood disorders in COPD. Although the current management of mood disorders such as depression in COPD involves using antidepressants, their use has been limited due to tolerability issues. On the other hand, as omega-3 polyunsaturated fatty acids (n-3 PUFAs) play a vital role in regulating inflammatory responses, they could be promising alternatives in managing mood disorders in COPD. This review discusses comorbid mood disorders in COPD as well as their influence on the progression and management of COPD. The underlying mechanisms of comorbid mood disorders in COPD will also be discussed, along with the potential role of n-3 PUFAs in managing these conditions.

Development of severe colitis is associated with lung inflammation and pathology

Inflammatory bowel diseases (IBD) such as Crohn’s disease and ulcerative colitis are chronic relapsing diseases that affect the gastrointestinal tract, most commonly the colon. A link between the gut and the lung is suggested since patients with IBD have an increased susceptibility for chronic inflammatory lung disease. Furthermore, in the absence of overt lung disease, IBD patients have worsened lung function and more leukocytes in sputum than healthy individuals, highlighting a conduit between the gut and lung in disease. To study the gut-lung axis in the context of IBD, we used TCRδ-/- mice, which are highly susceptible to dextran sulfate sodium (DSS) due to the importance of γδ T cells in maintenance of barrier integrity. After induction of experimental colitis using DSS, the lungs of TCRδ-/- mice exhibited signs of inflammation and mild emphysema, which was not observed in DSS-treated C57BL/6 mice. Damage to the lung tissue was accompanied by a large expansion of neutrophils in the lung parenchyma and an increase in alveolar macrophages in the lung wash. Gene expression analyses showed a significant increase in Csf3, Cxcl2, Tnfa, and Il17a in lung tissue in keeping with neutrophil infiltration. Expression of genes encoding reactive oxygen species enzymes and elastolytic enzymes were enhanced in the lungs of both C57BL/6 and TCRδ-/- mice with colitis. Similarly, surfactant gene expression was also enhanced, which may represent a protective mechanism. These data demonstrate that severe colitis in a susceptible genetic background is sufficient to induce lung inflammation and tissue damage, providing the research community with an important tool for the development of novel therapeutics aimed at reducing co-morbidities in IBD patients.

Short chain fatty acids: key regulators of the local and systemic immune response in inflammatory diseases and infections

The human intestinal microbiome substantially affects human health and resistance to infections in its dynamic composition and varying release of microbial-derived metabolites. Short-chain fatty acids (SCFA) produced by commensal bacteria through fermentation of indigestible fibres are considered key regulators in orchestrating the host immune response to microbial colonization by regulating phagocytosis, chemokine and central signalling pathways of cell growth and apoptosis, thereby shaping the composition and functionality of the intestinal epithelial barrier. Although research of the last decades provided valuable insight into the pleiotropic functions of SCFAs and their capability to maintain human health, mechanistic details on how SCFAs act across different cell types and other organs are not fully understood. In this review, we provide an overview of the various functions of SCFAs in regulating cellular metabolism, emphasizing the orchestration of the immune response along the gut-brain, the gut-lung and the gut-liver axes. We discuss their potential pharmacological use in inflammatory diseases and infections and highlight new options of relevant human three-dimensional organ models to investigate and validate their biological functions in more detail.

Prevalence of and Factors Associated with Respiratory Symptoms Among Patients with Inflammatory Bowel Disease: A Prospective Study

BACKGROUND

No large, prospective study has investigated respiratory symptoms in patients with inflammatory bowel diseases. We aimed to describe the prevalence of and factors associated with respiratory symptoms in patients with inflammatory bowel disease.

METHODS

In an observational, prospective, cross-sectional study, we evaluated the frequency of respiratory symptoms using a validated self-reporting questionnaire from February 2019 to February 2021 during routine follow-up outpatient visits of patients with inflammatory bowel disease followed in the Gastroenterology Department of the Nancy University Hospital. In case of a positive questionnaire, patients were systematically offered a consultation with a pulmonologist in order to investigate a potential underlying respiratory disease.

RESULTS

There were 325 patients included, and 180 patients had a positive questionnaire (144 with Crohn's disease). Of the included patients, 165 (50.8%) presented with respiratory symptoms, with dyspnea being the most frequent symptom (102 patients). There were 102 patients (56.7%) who benefited from a consultation in the pulmonology department: 43 (42.2%) were diagnosed with a respiratory disease, mainly asthma (n = 13) or chronic obstructive pulmonary disease (n = 10). Fourteen patients (13.7%) had obstructive sleep apnea. A body mass index increase, being a smoker or ex-smoker, and having articular extra-intestinal manifestations were independently associated with a higher prevalence of respiratory symptoms.

CONCLUSIONS

Half of patients with inflammatory bowel disease reported respiratory symptoms in our study. Patients with inflammatory bowel disease should be systematically screened, as pulmonary disease is frequently present in this population, with specific attention being given to smokers or ex-smokers and patients with extra-articular intestinal manifestations.

Gastrointestinal consequences of lipopolysaccharide-induced lung inflammation

BACKGROUND

Respiratory inflammation is the body's response to lung infection, trauma or hypersensitivity and is often accompanied by comorbidities, including gastrointestinal (GI) symptoms. Why respiratory inflammation is accompanied by GI dysfunction remains unclear. Here, we investigate the effect of lipopolysaccharide (LPS)-induced lung inflammation on intestinal barrier integrity, tight-junctions, enteric neurons and inflammatory marker expression.

METHODS

Female C57bl/6 mice (6-8 weeks) were intratracheally administered LPS (5 µg) or sterile saline, and assessed after either 24 or 72 h. Total and differential cell counts in bronchoalveolar lavage fluid (BALF) were used to evaluate lung inflammation. Intestinal barrier integrity was assessed via cross sectional immunohistochemistry of tight junction markers claudin-1, claudin-4 and EpCAM. Changes in the enteric nervous system (ENS) and inflammation in the intestine were quantified immunohistochemically using neuronal markers Hu + and nNOS, glial markers GFAP and S100β and pan leukocyte marker CD45.

RESULTS

Intratracheal LPS significantly increased the number of neutrophils in BALF at 24 and 72 h. These changes were associated with an increase in CD45 + cells in the ileal mucosa at 24 and 72 h, increased goblet cell expression at 24 h, and increased expression of EpCAM at 72 h. LPS had no effect on the expression of GFAP, S100β, nor the number of Hu + neurons or proportion of nNOS neurons in the myenteric plexus.

CONCLUSIONS

Intratracheal LPS administration induces inflammation in the ileum that is associated with enhanced expression of EpCAM, decreased claudin-4 expression and increased goblet cell density, these changes may contribute to systemic inflammation that is known to accompany many inflammatory diseases of the lung.

Gastrointestinal health: changes of intestinal mucosa and microbiota in patients with ulcerative colitis and irritable bowel syndrome from PM2.5-polluted regions of Ukraine

Here, clinical studies of patients were conducted to assess changes in patients with ulcerative colitis (UC) and irritable bowel syndrome (IBS) associated with air pollution by PM. A comparative study of 100 patients with UC and 75 with IBS from highly (HPRs) and low (LPRs) PM_2.5-polluted regions of Ukraine was conducted. Biopsy of the intestinal mucosa of patients with UC from HPRs showed severe cellular infiltration. Patients with IBS from HPRs had changes in the superficial epithelium (focal desquamation), and inflammatory-cellular infiltration of mucous membrane of the colon. In patients with UC, changes in mucus production were found, which were more significant in HPR patients. PAS response did not depend on the residence; the level of MUC2 was significantly lower in HPR patients with UC (1.12 vs 2.15 au). In patients with UC from HPRs, a decrease in Bacteroidetes (34.0 vs. 39.0 small intestinal bacterial overgrowth (SIBO), ppm) and an increase in Proteobacteria compared to LPRs were shown. In IBS patients, significant differences were found in the level of Proteobacteria, which was higher in HPRs. The level of regulatory flora Akkermansia muciniphila and Faecalibacterium prausnitzii reduced in patients with UC from HPRs. In patients from LPRs, the level of Akkermansia muciniphila raised above normal (2.8 vs 4.7 SIBO, ppm). Similar changes of regulatory flora have been identified in patients with IBS from different regions. Therefore, a more severe course of the disease (more pronounced cellular infiltration and violation of the microbiota) was shown in patients with UC from HPRs as compared to LPRs.

Gut-lung Microbiota Interactions in Chronic Obstructive Pulmonary Disease (COPD): Potential Mechanisms Driving Progression to COPD and Epidemiological Data

This paper focuses on the gut-lung axis in the context of Inflammatory Bowel Disease (IBD) and Chronic Obstructive Pulmonary Disease (COPD), highlighting the key role played by microbial dysbiosis and the impact of environmental and genetic factors on the innate and acquired immune system and on chronic inflammation in the intestinal and pulmonary tracts. Recent evidence indicates that Antigen-Presenting Cells (APCs) perform regulatory activity influencing the composition of the microbiota. APCs (macrophages, dendritic cells, B cells) possess membrane receptors known as Pattern Recognition Receptors (PRRs), a category of toll-like receptors (TLRs). PRRs recognise distinct microbial structures and microbial metabolites called Signals, which modulate the saprophytic microbial equilibrium of the healthy microbiota by recognising molecular profiles associated with commensal microbes (Microbe-Associated Molecular Patterns, MAMPs). During dysbiosis, pathogenic bacteria can prompt an inflammatory response, producing PAMPs (Pathogen-Associated Molecular Patterns) thereby activating the proliferation of inflammatory response cells, both local and systemic. This series of regulatory and immune-response events is responsible (together with chronic infection, incorrect diet, obesity, etc.) for the systemic chronic inflammation (SCI) known as "low-grade inflammation" typical of COPD and IBD. This review looks at immunological research and explores the role of the microbiota, looking at two recent clinical studies, SPIROMICS and AERIS. There is a need for further clinical studies to characterize the pulmonary microbiota and to obtain new information about the pathogenesis of lung disease to improve our knowledge and treatment strategies and identify new therapeutic targets.

Gut-Lung Microbiota Interaction in COPD Patients: A Literature Review

Respiratory diseases are one of the leading causes of death in the world, which is why a lot of attention has been recently paid to studying the possible mechanisms for the development of pulmonary diseases and assessing the impact on their course. The microbiota plays an important role in these processes and influences the functionality of the human immune system. Thus, alterations in the normal microflora contribute to a reduction in immunity and a more severe course of diseases. In this review, we summarized the information about gut and lung microbiota interactions with particular attention to their influence on the course of chronic obstructive pulmonary disease (COPD).

Forsythiae Fructuse extracts alleviates LPS-induced acute lung injury in mice by regulating PPAR-γ/RXR-α in lungs and colons

ETHNOPHARMACOLOGICAL RELEVANCE

Forsythiae Fructuse (FF), the dried fruit of Forsythia suspensa (Thunb.) Vahl, is used as a traditional Chinese medicine that has been reported to exert good anti-inflammatory effects in the treatment of many lung diseases.

AIM OF THE STUDY

The purpose of this study was to investigate the anti-inflammatory mechanism of FF in the treatment of acute lung injury (ALI) based on gut-lung axis.

MATERIALS AND METHODS

ALI model was established by the intratracheal instillation of 5 mg/kg LPS in ICR mice. Mice were administered intragastrically with dexamethasone (DEX), and low-dose, medium-dose and high-dose of FF extracts (LFF, MFF and HFF) in addition to the mice of control (CON) and model (MOD) groups. Pathological observation and inflammation scoring of lung tissues were based on HE staining. Limulus lysate assay was used to detect endotoxin levels in serum. Western blot and Real-time quantitative PCR were respectively applied to detect the protein and mRNA expressions in both lung and colon tissues.

RESULTS

Lung pathological injury, inflammatory score and inflammatory genes (IL-6, IL-1β, TNF-α) could be effectively suppressed by FF in LPS-induced ALI mice. FF also increased the proteins of epithelial markers (E-cadherin, ZO-1 and Claudin-1) in lung and colon tissues, and decreased colonic inflammatory genes for protecting the epithelial barriers of lung and colon. The protein expression of TLR4/MAPK/NF-κB inflammatory signaling pathway in lung and colon was significantly inhibited by FF via the regulation of PPAR-γ, a nuclear hormone receptor that forms the heterodimer with RXR-α to inhibit inflammatory gene transcription. More specifically, FF promoted the upregulation of protein, phosphorylated proteins and genes of PPAR-γ/RXR-α in lungs, while inhibited the protein overexpression and phosphorylation of PPAR-γ/RXR-α in colons.

CONCLUSIONS

FF exhibited anti-inflammatory effects and protected the epithelial barriers in lungs and colons by regulating PPAR-γ/RXR-α in the treatment of LPS-induced ALI.

Association of sirtuins (SIRT1-7) with lung and intestinal diseases

"Exterior-interior correlation between the lung and large intestine" is one of the important contents of traditional Chinese medicine. This theory describes the role of the lung and the intestine in association with disease treatment. The "lung-gut" axis is a modern extension of the "exterior-interior correlation between lung and large intestine" theory in TCM. Sirtuin (SIRT) is a nicotinamide adenine dinucleotide (NAD⁺)-dependent enzyme family with deacetylase properties, which is highly conserved from bacteria to humans. The sirtuin defines seven silencing regulatory proteins (SIRT1-7) in human cells. It can regulate aging, metabolism, and certain diseases. Current studies have shown that sirtuins have dual characteristics, acting as both tumor promoters and tumor inhibitors in cancers. This paper provides a comparative summary of the roles of SIRT1-7 in the intestine and lung (both inflammatory diseases and tumors), and the promoter/suppressor effects of targeting SIRT family microRNAs and modulators of inflammation or tumors. Sirtuins have great potential as drug targets for the treatment of intestinal and respiratory diseases. Meanwhile, it may provide new ideas of future drug target research.

Role of Short-Chain Fatty Acids Produced by Gut Microbiota in Innate Lung Immunity and Pathogenesis of the Heterogeneous Course of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a widespread socially significant disease. The development of COPD involves the innate immune system. Interestingly, the regulation of the innate lung immune system is related to the gut microbiota. This connection is due to the production by gut microorganisms of short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate. Nutritional disturbances and changes in the structure of the intestinal microbiota lead to a decrease in SCFAs production and their effect on pulmonary immunity. The presence of a metabolic and immune axis linking the lungs and gut plays an important role in the pathogenesis of COPD. In addition, the nature of nutrition and SCFAs may participate in the development of the clinically heterogeneous course of COPD.

Emerging trends and hotspot in gut-lung axis research from 2011 to 2021: a bibliometrics analysis

BACKGROUND

Increasing attention has been paid to the potential relationship between gut and lung. The bacterial dysbiosis in respiratory tract and intestinal tract is related to inflammatory response and the progress of lung diseases, and the pulmonary diseases could be improved by regulating the intestinal microbiome. This study aims to generate the knowledge map to identify major the research hotspots and frontier areas in the field of gut-lung axis.

MATERIALS AND METHODS

Publications related to the gut-lung axis from 2011 to 2021 were identified from the Web of Science Core Collection. CiteSpace 5.7.R2 software was used to analyze the publication years, journals, countries, institutions, and authors. Reference co-citation network has been plotted, and the keywords were used to analyze the research hotspots and trends.

RESULTS

A total of 3315 publications were retrieved and the number of publications per year increased over time. Our results showed that Plos One (91 articles) was the most active journal and The United States (1035 articles) published the most articles. We also observed the leading institution was the University of Michigan (48 articles) and Huffnagle Gary B, Dickson Robert P and Hansbro Philip M, who have made outstanding contributions in this field.

CONCLUSION

The Inflammation, Infection and Disease were the hotspots, and the regulation of intestinal flora to improve the efficacy of immunotherapy in lung cancer was the research frontier. The research has implications for researchers engaged in gut-lung axis and its associated fields.

Microbiome Modulation as a Novel Strategy to Treat and Prevent Respiratory Infections

Acute and chronic lower airway disease still represent a major cause of morbidity and mortality on a global scale. With the steady rise of multidrug-resistant respiratory pathogens, such as Pseudomonas aeruginosa and Klebsiella pneumoniae, we are rapidly approaching the advent of a post-antibiotic era. In addition, potentially detrimental novel variants of respiratory viruses continuously emerge with the most prominent recent example being severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To this end, alternative preventive and therapeutic intervention strategies will be critical to combat airway infections in the future. Chronic respiratory diseases are associated with alterations in the lung and gut microbiome, which is thought to contribute to disease progression and increased susceptibility to infection with respiratory pathogens. In this review we will focus on how modulating and harnessing the microbiome may pose a novel strategy to prevent and treat pulmonary infections as well as chronic respiratory disease.

Microbiota medicine: towards clinical revolution

The human gastrointestinal tract is inhabited by the largest microbial community within the human body consisting of trillions of microbes called gut microbiota. The normal flora is the site of many physiological functions such as enhancing the host immunity, participating in the nutrient absorption and protecting the body against pathogenic microorganisms. Numerous investigations showed a bidirectional interplay between gut microbiota and many organs within the human body such as the intestines, the lungs, the brain, and the skin. Large body of evidence demonstrated, more than a decade ago, that the gut microbial alteration is a key factor in the pathogenesis of many local and systemic disorders. In this regard, a deep understanding of the mechanisms involved in the gut microbial symbiosis/dysbiosis is crucial for the clinical and health field. We review the most recent studies on the involvement of gut microbiota in the pathogenesis of many diseases. We also elaborate the different strategies used to manipulate the gut microbiota in the prevention and treatment of disorders. The future of medicine is strongly related to the quality of our microbiota. Targeting microbiota dysbiosis will be a huge challenge.

Relationship between gut microbiota and lung function decline in patients with chronic obstructive pulmonary disease: a 1-year follow-up study

OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease characterized by a persistent limitation in airflow. Gut microbiota is closely correlated with lung inflammation. However, gut microbiota has not been studied in patients with declining lung function, due to chronic lung disease progression.

SUBJECTS AND METHODS

Stool samples were obtained from 55 patients with COPD that were in stable condition at enrolment (stage 1) and at a 1-year follow-up (stage 2). After extracting stool DNA, we performed next generation sequencing to analyse the distribution of gut microbiota.

RESULTS

Patients were divided to control and declining lung function groups, based on whether the rate of forced expiratory volume in 1 s (FEV₁) had declined over time. An alpha diversity analysis of initial and follow-up stool samples showed a significant difference in the community richness of microbiota in the declining function group, but not in the control group. At the phylum level, Bacteroidetes was more abundant in the control group and Firmicutes was more abundant in the declining function group. The Alloprevotella genus was more abundant in the control group than in the declining function group. At 1-year follow-up, the mean proportions of Acinetobacter and Stenotrophomonas significantly increased in the control and declining function groups, respectively.

CONCLUSION

Some community shifts in gut microbiota were associated with lung function decline in COPD patients under regular treatment. Future studies should investigate the mechanism underlying alterations in lung function, due to changes in gut bacterial communities, in COPD.

Novel pharmacological strategies to treat cognitive dysfunction in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and currently the 3rd largest cause of death in the world, with approximately 3.23 million deaths per year. Globally, the financial burden of COPD is approximately €82 billion per year and causes substantial morbidity and mortality. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities and viral and bacterial-induced acute exacerbations (AECOPD). Recent clinical studies have shown that cognitive dysfunction is present in up to 60% of people with COPD, with impairments in executive function, memory, and attention, impacting on important outcomes such as quality of life, hospitalisation and survival. The high prevalence of cognitive dysfunction in COPD may also help explain the insufficient adherence to therapeutic plans and strategies, thus worsening disease progression in people with COPD. However, the mechanisms underlying the impaired neuropathology and cognition in COPD remain largely unknown. In this review, we propose that the observed pulmonary oxidative burden and inflammatory response of people with COPD 'spills over' into the systemic circulation, resulting in damage to the brain and leading to cognitive dysfunction. As such, drugs targeting the lungs and comorbidities concurrently represent an exciting and unique therapeutic opportunity to treat COPD and cognitive impairments, which may lead to the production of novel targets to prevent and reverse the debilitating and life-threatening effects of cognitive dysfunction in COPD.

Comorbidity before and after a diagnosis of inflammatory bowel disease

BACKGROUND

Comorbidity is an important predictor of how disease course in inflammatory bowel (IBD) evolves.

AIMS

To determine pre-diagnosis relative rates (RR) and post-diagnosis hazard ratios (HR) of component diseases of the Charlson Comorbidity Index (CCI) in a cohort study of persons with IBD.

METHODS

The University of Manitoba IBD Epidemiology Database includes all Manitobans with IBD from 1 April 1984 through 31 March 2018 and matched controls. All outpatient physician claims and hospital discharge abstracts were searched for diagnostic codes for CCI component diseases. Some diseases were collapsed into one group such that we assessed 12 conditions. We report the RR of these conditions prior to IBD and the incidence of these diagnoses after IBD. Using Cox proportional hazards regression we report post-diagnosis HR. Confidence intervals were adjusted for Bonferroni correction.

RESULTS

The RR of cardiovascular diseases, peripheral vascular diseases, chronic pulmonary diseases, connective tissue disease/rheumatic diseases, renal disease, liver diseases, peptic ulcer disease, and cancer were all increased prior to diagnoses of IBD compared to controls. All comorbidities were increased post IBD diagnosis. The increased HR for dementia in persons with Crohn's disease was a concerning novel finding. The increased association with paraplegia/hemiplegia was unexpected. For all comorbidities, except diabetes, the age at diagnosis was younger in IBD than controls.

CONCLUSIONS

Persons with IBD have a higher comorbidity burden than persons without IBD. Optimal care plans for persons with IBD should include an assessment for other comorbidities that include just about every other organ system.

Risk of gastric cancer in chronic obstructive pulmonary disease

OBJECTIVE

Owing to the potential role of the gut-lung axis in carcinogenesis, we assessed the incidence of gastric cancer in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Using Quebec's administrative databases, we assembled a cohort of 118 913 patients aged 40 years and older with COPD from 1995 to 2015. We calculated age-standardized incidence rate ratio (IRR) and 95% confidence interval (CI) for gastric cancer, comparing patients with COPD to the Quebec general population. We evaluated temporal changes in incidence by calculating annual percentage change (APC) and stratified the analysis by anatomical site.

RESULTS

Between 1995 and 2015, 279 patients with COPD developed gastric cancer (54.0 cases per 100 000 person-years). The overall age-standardized incidence rate in patients with COPD was comparable to the general population (IRR, 1.05; 95% CI, 0.79-1.39). However, the IRR increased over time (APC, 4.40%; P = 0.0101), due to the growing rate of gastric cancer in patients with COPD (APC, 1.90%; P = 0.2666) and the declining rate in the Quebec population (APC, -2.40%; P < 0.0001).

CONCLUSIONS

The overall risk of gastric cancer in patients with COPD did not differ from the general population; however, the risk among patients has increased over the years. These findings provide insights as to whether long-term follow-up for gastric cancer risk in COPD is warranted.

Ebselen prevents cigarette smoke-induced gastrointestinal dysfunction in mice

Gastrointestinal (GI) dysfunction is a common comorbidity of chronic obstructive pulmonary disease (COPD) for which a major cause is cigarette smoking (CS). The underlying mechanisms and precise effects of CS on gut contractility, however, are not fully characterised. Therefore, the aim of the present study was to investigate whether CS impacts GI function and structure in a mouse model of CS-induced COPD. We also aimed to investigate GI function in the presence of ebselen, an antioxidant that has shown beneficial effects on lung inflammation resulting from CS exposure. Mice were exposed to CS for 2 or 6 months. GI structure was analysed by histology and immunofluorescence. After 2 months of CS exposure, ex vivo gut motility was analysed using video-imaging techniques to examine changes in colonic migrating motor complexes (CMMCs). CS decreased colon length in mice. Mice exposed to CS for 2 months had a higher frequency of CMMCs and a reduced resting colonic diameter but no change in enteric neuron numbers. Ten days cessation after 2 months CS reversed CMMC frequency changes but not the reduced colonic diameter phenotype. Ebselen treatment reversed the CS-induced reduction in colonic diameter. After 6 months CS, the number of myenteric nitric-oxide producing neurons was significantly reduced. This is the first evidence of colonic dysmotility in a mouse model of CS-induced COPD. Dysmotility after 2 months CS is not due to altered neuron numbers; however, prolonged CS-exposure significantly reduced enteric neuron numbers in mice. Further research is needed to assess potential therapeutic applications of ebselen in GI dysfunction in COPD.

Subclinical Pulmonary Involvement in Active IBD Responds to Biologic Therapy

OBJECTIVE

Increased mortality from respiratory diseases was observed in epidemiological studies of patients with ulcerative colitis [UC] as a potentially underestimated extraintestinal manifestation. We therefore investigated the presence of pulmonary manifestations of inflammatory bowel disease [IBD] and the potential effect of tumour necrosis factor alpha [TNF-α] inhibitors on pulmonary function tests [PFT] in a prospective, longitudinal study.

METHODS

In all, 92 consecutive patients with IBD (49 Crohn´s disease [CD], 43 UC) and 20 healthy controls were recruited. Fifty patients with IBD were in remission, and 42 had active disease with 22 of these being examined before and 6 weeks after initiating anti-TNF therapy. Pulmonary function tests [PFT] were evaluated using the Medical Research Council [MRC] dyspnoea index and a standardized body plethysmography. IBD activity was assessed using Harvey-Bradshaw index for CD and partial Mayo score for UC. Data are presented as mean ± standard error of the mean [SEM].

RESULTS

Patients with active IBD showed significant reduction of PFT. Forced expiration [Tiffeneau index] values [FEV1%] were significantly reduced in IBD patients with active disease [78.8 ± 1.1] compared with remission [86.1 ± 0.9; p = 0.0002] and with controls [87.3 ± 1.3; p = 0.001]. Treatment with anti-TNF induced a significant relief in obstruction [p = 0.003 for FEV1% in comparison with baseline levels]. The level of pulmonary obstruction significantly correlated with clinical inflammation scores [HBI or Mayo].

CONCLUSIONS: PATIENTS

with active IBD present with significant obstructive abnormalities in their PFTs. Obstruction is related to inflammatory activity, with anti-TNF improving PFTs. Pulmonary obstruction and possibly chronic bronchopulmonary inflammation is an overlooked problem in active IBD that is probably obscured by intestinal symptoms.

The Gut-Lung Axis in Systemic Inflammation. Role of Mesenteric Lymph as a Conduit

Emerging evidence shows that after injury or infection, the mesenteric lymph acts as a conduit for gut-derived toxic factors to enter the blood circulation, causing systemic inflammation and acute lung injury. Neither the cellular and molecular identity of lymph factors nor their mechanisms of action have been well understood and thus have become a timely topic of investigation. This review will first provide a summary of background knowledge on gut barrier and mesenteric lymphatics, followed by a discussion focusing on the current understanding of potential injurious factors in the lymph and their mechanistic contributions to lung injury. We also examine lymph factors with antiinflammatory properties as well as the bidirectional nature of the gut-lung axis in inflammation.

Disease-associated gut microbiome and metabolome changes in patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is the third commonest cause of death globally, and manifests as a progressive inflammatory lung disease with no curative treatment. The lung microbiome contributes to COPD progression, but the function of the gut microbiome remains unclear. Here we examine the faecal microbiome and metabolome of COPD patients and healthy controls, finding 146 bacterial species differing between the two groups. Several species, including Streptococcus sp000187445, Streptococcus vestibularis and multiple members of the family Lachnospiraceae, also correlate with reduced lung function. Untargeted metabolomics identifies a COPD signature comprising 46% lipid, 20% xenobiotic and 20% amino acid related metabolites. Furthermore, we describe a disease-associated network connecting Streptococcus parasanguinis_B with COPD-associated metabolites, including N-acetylglutamate and its analogue N-carbamoylglutamate. While correlative, our results suggest that the faecal microbiome and metabolome of COPD patients are distinct from those of healthy individuals, and may thus aid in the search for biomarkers for COPD.

Chronic obstructive pulmonary disease (COPD) is a progressing disease, with lung but not gut microbiota implicated in its etiology. Here the authors compare the stool from patients with COPD and healthy controls to find specific gut bacteria and metabolites associated with active disease, thereby hinting at a potential role for the gut microbiome in COPD.

Intestinal function is impaired in patients with Chronic Obstructive Pulmonary Disease

BACKGROUND & AIMS

Gastrointestinal symptoms are prevalent extrapulmonary systemic manifestations of Chronic Obstructive Pulmonary Disease (COPD), but have been rarely studied. We dissected the perturbations in intestinal function in human patients with COPD using comprehensive metabolic and physiological approaches.

METHODS

In this observational study, small intestinal membrane integrity and active carrier-mediated glucose transport were quantified by sugar permeability test in 21 clinically stable patients with moderate to severe COPD (mean FEV₁, 41.2 (3.2) % of predicted) and 16 healthy control subjects. Protein digestion and absorption was analyzed using stable tracer kinetic methods. Plasma acetate, propionate, and butyrate concentrations were measured as markers of intestinal microbial metabolism.

RESULTS

Compared with healthy controls, non carrier-mediated permeability was higher (0.062 (95% CI [0.046, 0.078]) vs. 0.037 (95% CI [0.029, 0.045]), P = 0.009) and active glucose transport lower in COPD (31.4 (95% CI [23.4, 39.4])% vs. 48.0 (95% CI [37.8, 58.3])%, P = 0.010). Protein digestion and absorption was lower in COPD (0.647 (95% CI [0.588, 0.705]) vs. 0.823 (95% CI [0.737, 0.909]), P = 0007), and impairment greater in patients with dyspnea (P = 0.038), exacerbations in preceding year (P = 0.052), and reduced transcutaneous oxygen saturation (P = 0.051), and was associated with reduced physical activity score (P = 0.016) and lower quality of life (P = 0.0007). Plasma acetate concentration was reduced in COPD (41.54 (95% CI [35.17, 47.91]) vs. 80.44 (95% CI [54.59, 106.30]) μmol/L, P = 0.001) suggesting perturbed intestinal microbial metabolism.

CONCLUSIONS

We conclude that intestinal dysfunction is present in COPD, worsens with increasing disease severity, and is associated with reduced quality of life.

Links Between Inflammatory Bowel Disease and Chronic Obstructive Pulmonary Disease

Inflammatory bowel disease (IBD) and chronic obstructive pulmonary disease (COPD) are chronic inflammatory diseases of the gastrointestinal and respiratory tracts, respectively. These mucosal tissues bear commonalities in embryology, structure and physiology. Inherent similarities in immune responses at the two sites, as well as overlapping environmental risk factors, help to explain the increase in prevalence of IBD amongst COPD patients. Over the past decade, a tremendous amount of research has been conducted to define the microbiological makeup of the intestine, known as the intestinal microbiota, and determine its contribution to health and disease. Intestinal microbial dysbiosis is now known to be associated with IBD where it impacts upon intestinal epithelial barrier integrity and leads to augmented immune responses and the perpetuation of chronic inflammation. While much less is known about the lung microbiota, like the intestine, it has its own distinct, diverse microflora, with dysbiosis being reported in respiratory disease settings such as COPD. Recent research has begun to delineate the interaction or crosstalk between the lung and the intestine and how this may influence, or be influenced by, the microbiota. It is now known that microbial products and metabolites can be transferred from the intestine to the lung via the bloodstream, providing a mechanism for communication. While recent studies indicate that intestinal microbiota can influence respiratory health, intestinal dysbiosis in COPD has not yet been described although it is anticipated since factors that lead to dysbiosis are similarly associated with COPD. This review will focus on the gut-lung axis in the context of IBD and COPD, highlighting the role of environmental and genetic factors and the impact of microbial dysbiosis on chronic inflammation in the intestinal tract and lung.

Inflammatory Bowel Disease and Obstructive Pulmonary Disease: A Two-way Association?

Inflammatory bowel diseases (IBD) is an umbrella term that covers both ulcerative colitis (UC) and Crohn's disease (CD), which are chronic inflammatory conditions of the gastrointestinal system. Airway diseases are one of the most commonly studied manifestations of IBD. It is observed that populations with pre-existing obstructive pulmonary conditions are at higher risk of new-onset IBD. This newly documented evidence of increased incidence of IBD among patients with pulmonary diseases and the higher than the estimated prevalence of pulmonary diseases among IBD sufferers support the hypothesis of a two-way association. This review article focuses on summarizing the current knowledge and available evidence regarding the association between IBD and obstructive pulmonary diseases such as chronic obstructive pulmonary disease (COPD), emphysema, bronchiectasis, and asthma.

We utilized PubMed as the primary search source and database and included the free full-text articles available on it, published over the past five years. We reviewed literature from multiple regions of the world, such as the US, UK, China, and Canada and compiled this traditional review article utilizing the information collected from 4,966,459 patients. Specifications such as age and gender were not mentioned in all articles.

This review will serve to strengthen the existing research database concerning the relationship between IBD and obstructive pulmonary diseases. It will help to highlight the significance of the two-way association between IBD and obstructive pulmonary disease and the importance of treating these two conditions simultaneously. It will also raise awareness about the importance of timely detection of IBD and associated airway complications, leading to decreased disease burden and the treatment cost.

Risk of inflammatory bowel disease in patients with chronic obstructive pulmonary disease: A nationwide, population-based study

BACKGROUND

There is a growing evidence regarding an increased risk of inflammatory bowel disease (IBD) among patients with airway diseases.

AIM

To investigate the influence of chronic obstructive pulmonary disease (COPD) on the risk of IBD.

METHODS

A nationwide, population-based study was conducted using data from the National Health Insurance Service database. A total of 1303021 patients with COPD and 6515105 non-COPD controls were identified. The COPD group was divided into the severe and the mild COPD group according to diagnostic criteria. The risk of IBD in patients with COPD compared to controls was analyzed by Cox proportional hazard regression models. The cumulative incidences of IBD were compared between the groups.

RESULTS

The COPD group had higher incidences of IBD compared to non-COPD controls (incidence rate, 9.98 vs 7.18 per 100000 person-years, P < 0.001). The risk of IBD in the COPD group was increased by 1.38 (adjusted hazard ratio (HR); 95%CI: 1.25-1.52). The incidence rate of IBD was higher in the severe COPD group than in the mild COPD group (12.39 vs 9.77 per 100000 person-year, P < 0.001). The severity of COPD was associated with an increased risk of IBD (adjusted HR 1.70 in severe COPD, 95%CI: 1.27-2.21 and adjusted HR 1.35 in mild COPD, 95%CI: 1.22-1.49)

CONCLUSION

The incidences of IBD were significantly increased in COPD patients in South Korea and the risk of developing IBD also increased as the severity of COPD increased.

Epidemiology and Outcomes of Hospitalized Inflammatory Bowel Disease Patients with Asthma in the United States

Introduction Research on the epidemiology and outcomes of hospitalized inflammatory bowel disease (IBD) patients with a history of asthma in the United States (US) is limited. This study aimed at identifying the sociodemographic and clinical characteristics of hospitalized IBD patients with a diagnosis of asthma. We also examined the association between an asthma diagnosis and the length of stay (LOS) and in-hospital mortality among hospitalized IBD patients. Method Using the National Inpatient Sample (NIS) for the years 2008-2013 and the ninth edition of the International Classification of Diseases codes, we identified adult hospitalized patients with IBD (N = 370,636) and used weighted multilevel hierarchical logistic regression models. Results The overall prevalence of asthma in our cohort of hospitalized IBD patients was 8%. Hospitalized IBD patients with asthma were more likely to be female, <45 years old, have Crohn's disease, and a higher Elixhauser comorbidity index (ECI). IBD patients with ECI of 3 or more had higher odds of having a prior diagnosis of asthma compared to those with no comorbidities (OR 63.33, 95% CI: 54.51-73.58). Having a prior diagnosis of asthma among hospitalized IBD patients was associated with lower odds of prolonged hospital stay and in-hospital mortality (OR 0.72, 95% CI: 0.69-0.74; OR 0.49, 95% CI: 0.43- 0.56, respectively). Patients with both IBD and asthma are more likely to seek medical care with earlier and aggressive treatment modalities, which may explain the lower in-hospital mortality in this group. Conclusion Lower in-hospital mortality and geographic variation are notable in the outcomes of IBD patients with asthma. Future prospective studies are necessary to improve our understanding of the management and interplay of IBD patients with asthma.

Association between inflammatory bowel disease and chronic obstructive pulmonary disease: a systematic review and meta-analysis

INTRODUCTION

There is evidence of an association between inflammatory bowel disease (IBD) and lung conditions such as chronic obstructive pulmonary disease (COPD). This systematic review and meta-analysis explored the risk of new onset IBD in patients with COPD and new onset COPD in IBD patients.

METHODS

We performed a systematic review of observational studies exploring the risk of both associations. Two independent reviewers explored the EMBASE, MEDLINE, LILACS and DOAJ databases, and the risk of bias was evaluated using the ROBBINS-I tool. Data from included studies was pooled in a random effect meta-analysis following a DerSimonian-Laird method. The quality of the evidence was ranked using GRADE criteria.

RESULTS

Four studies including a pooled population of 1355 new cases were included. We found association between new onset IBD in COPD population. The risk of bias was low in most of them. Only one study reported tobacco exposure as a potential confounding factor. The pooled risk ratio (RR) for a new diagnosis of IBD in COPD patients was 2.02 (CI, 1.56 to 2.63), I2 = 72% (GRADE: low). The subgroup analyses for Crohn's disease and ulcerative colitis yielded RRs of 2.29 (CI, 1.51 to 3.48; I2 = 62%), and 1.79 (CI, 1.39 to 2.29; I2 = 19%.), respectively.

DISCUSSION

According to our findings, the risk of new onset IBD was higher in populations with COPD compared to the general population without this condition. Based on our analysis, we suggest a potential association between IBD and COPD; however, further research exploring the potential effect of confounding variables, especially cigarette smoking, is still needed. REVIEW REGISTER: (PROSPERO: CRD42018096624).

Extraintestinal Manifestations of Inflammatory Bowel Disease: Epidemiology, Etiopathogenesis, and Management

PURPOSE OF REVIEW

Extraintestinal manifestations (EIMs) of inflammatory bowel disease (IBD) represent a complex array of disease processes with variable epidemiologic penetrance, genetic antecedents, and phenotypic presentations. The purpose of this review is to provide an overview of primary and secondary EIMs as well as salient treatment strategies utilized.

RECENT FINDINGS

While the genetic antecedents remain incompletely understood, the treatment armamentarium for EIMs has expanded with new pharmaceutical drug classes that effectively treat IBD. EIMs are an increasingly recognized complication of IBD that require prompt recognition, multidisciplinary management, and a multifaceted therapeutic approach. This review highlights the complexities and ramifications of EIM management and offers therapeutic guidance.

The gut and the inflammatory bowel diseases inside-out: extra-intestinal manifestations

An increasing deal of attention is being conveyed on the extra-intestinal manifestations (EIM) of inflammatory bowel diseases (IBD). We compiled the present review in an attempt to upgrade the accuracy of the classification of such polymorphic entities. We focused on three patterns. First, the conventional EIM localized to bone and joints, to the eye, to the biliary tree and to the skin. Second, the so-called IBD-like syndromes accompanied by bone marrow-derived anomalies of innate or acquired immunity. Third, specific disorders of the skin and of the lungs. EIM are thought to derive from an altered gut permeability, the release of cross-reacting antigens, and subsequent peripheral inflammation; T helper 17 cells boosted by a polymorphic interleukin 23 circuitry would be the main effectors of this chain. Inflammatory bowel disease-like pictures would derive from inborn errors of the immune response causing undue inflammation home to the gut. Monogenic IBD belong to this subset, and are of specific pediatric interest. Psoriasis, chronic obstructive pulmonary disease, and IBD are all inflammatory disorders of the barrier organs: skin, lungs, and gut. The demonstration that specific antigen hyper- or hyporesponsiveness raised at any of the three districts can modulate the response of the other two sites, has led to the innovative concept of a system-wide mucosal immunological organ. An improved knowledge of these entities has not only a speculative importance, but can also bear a clinical impact, insofar as EIM prove often more disabling than the underlying IBD itself.

Gastrointestinal microbiota contributes to the development of murine transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is a syndrome of respiratory distress upon blood transfusion and is the leading cause of transfusion-related fatalities. Whether the gut microbiota plays any role in the development of TRALI is currently unknown. We observed that untreated barrier-free (BF) mice suffered from severe antibody-mediated acute lung injury, whereas the more sterile housed specific pathogen-free (SPF) mice and gut flora-depleted BF mice were both protected from lung injury. The prevention of TRALI in the SPF mice and gut flora-depleted BF mice was associated with decreased plasma macrophage inflammatory protein-2 levels as well as decreased pulmonary neutrophil accumulation. DNA sequencing of amplicons of the 16S ribosomal RNA gene revealed a varying gastrointestinal bacterial composition between BF and SPF mice. BF fecal matter transferred into SPF mice significantly restored TRALI susceptibility in SPF mice. These data reveal a link between the gut flora composition and the development of antibody-mediated TRALI in mice. Assessment of gut microbial composition may help in TRALI risk assessment before transfusion.

The Gut Microbiome Signatures Discriminate Healthy From Pulmonary Tuberculosis Patients

Cross talk occurs between the human gut and the lung through a gut-lung axis involving the gut microbiota. However, the signatures of the human gut microbiota after active Mycobacterium tuberculosis infection have not been fully understood. Here, we investigated changes in the gut microbiota in tuberculosis (TB) patients by shotgun sequencing the gut microbiomes of 31 healthy controls and 46 patients. We observed a dramatic changes in gut microbiota in tuberculosis patients as reflected by significant decreases in species number and microbial diversity. The gut microbiota of TB patients were mostly featured by the striking decrease of short-chain fatty acids (SCFAs)-producingbacteria as well as associated metabolic pathways. A classification model based on the abundance of three species, Haemophilus parainfluenzae, Roseburia inulinivorans, and Roseburia hominis, performed well for discriminating between healthy and diseased patients. Additionally, the healthy and diseased states can be distinguished by SNPs in the species of B. vulgatus. We present a comprehensive profile of changes in the microbiota in clinical TB patients. Our findings will shed light on the design of future diagnoses and treatments for M. tuberculosis infections.

Psychological co-morbidities in COPD: Targeting systemic inflammation, a benefit for both?

COPD is a chronic lung disease characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities. Furthermore, COPD is often characterized by extrapulmonary manifestations and comorbidities worsening COPD progression and quality of life. A neglected comorbidity in COPD management is mental health impairment defined by anxiety, depression and cognitive problems. This paper summarizes the evidence for impaired mental health in COPD and focuses on current pharmacological intervention strategies. In addition, possible mechanisms in impaired mental health in COPD are discussed with a central role for inflammation. Many comorbidities are associated with multi-organ-associated systemic inflammation in COPD. Considering the accumulative evidence for a major role of systemic inflammation in the development of neurological disorders, it can be hypothesized that COPD-associated systemic inflammation also affects the function of the brain and is an interesting therapeutic target for nutra- and pharmaceuticals.

Chronic cigarette smoke exposure induces systemic hypoxia that drives intestinal dysfunction

Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract (GIT). Cigarette smoke (CS) exposure and chronic obstructive pulmonary disease (COPD) are risk factors for CD, although the mechanisms involved are poorly understood. We employed a mouse model of CS-induced experimental COPD and clinical studies to examine these mechanisms. Concurrent with the development of pulmonary pathology and impaired gas exchange, CS-exposed mice developed CD-associated pathology in the colon and ileum, including gut mucosal tissue hypoxia, HIF-2 stabilization, inflammation, increased microvasculature, epithelial cell turnover, and decreased intestinal barrier function. Subsequent smoking cessation reduced GIT pathology, particularly in the ileum. Dimethyloxaloylglycine, a pan-prolyl hydroxylase inhibitor, ameliorated CS-induced GIT pathology independently of pulmonary pathology. Prior smoke exposure exacerbated intestinal pathology in 2,4,6-trinitrobenzenesulfonic acid-induced (TNBS-induced) colitis. Circulating vascular endothelial growth factor, a marker of systemic hypoxia, correlated with CS exposure and CD in mice and humans. Increased mucosal vascularisation was evident in ileum biopsies from CD patients who smoke compared with nonsmokers, supporting our preclinical data. We provide strong evidence that chronic CS exposure and, for the first time to our knowledge, associated impaired gas exchange cause systemic and intestinal ischemia, driving angiogenesis and GIT epithelial barrier dysfunction, resulting in increased risk and severity of CD.

Correlation of Severity of Functional Gastrointestinal Disease Symptoms with that of Asthma and Chronic Obstructive Pulmonary Disease: A Multicenter Study

Introduction

There is a growing clinical awareness about the influence of gut-lung axis on lung injury and coexisting manifestations of disease processes in both the intestine and lungs. Patients of chronic lung diseases such as chronic obstructive pulmonary disease (COPD) and asthma very often present with coexistent gut symptoms. In the present study, we have tried to establish the correlation of severity of pulmonary pathology of COPD and asthma patients with functional gastrointestinal (GI) symptoms of the patients.

Materials and Methods

This is a prospective, questionnaire-based study comprising patients with asthma and COPD. After following strict inclusion and exclusion criteria, a total of 200 patients (100 patients of bronchial asthma and 100 patients of COPD) were included in the study. Functional GI symptom questionnaire [Annexure 1-Bowel Disease Questionnaire] is based on ROME III diagnostic criteria. On the basis of GOLD (Global Initiative for Obstructive Lung Disease) guidelines, COPD patients were divided into 4 categories (mild - GOLD 1, moderate - GOLD2, severe - GOLD3 and very severe - GOLD4). Asthma patients were divided into three categories (well controlled, partly controlled, uncontrolled) on the basis of GINA (Global Initiative for Asthma) guidelines.

Results

Highest percentage of patients with maximum GI symptoms was found in "GOLD-4" group among COPD patients and "uncontrolled" group among asthma patients. Highest percentage of patients with least GI symptoms was found in "GOLD-1" group among COPD patients and "well controlled" group among asthma patients.

Conclusion

We can conclude from our study that the phenomenon of gut-lung axis not only exists but also the severity of symptoms of one system (gut) carries a high degree of concordance with severity of other (lung).

Exploring the microbiome in health and disease

The analysis of human microbiome is an exciting and rapidly expanding field of research. In the past decade, the biological relevance of the microbiome for human health has become evident. Microbiome comprises a complex collection of microorganisms, with their genes and metabolites, colonizing different body niches. It is now well known that the microbiome interacts with its host, assisting in the bioconversion of nutrients and detoxification, supporting immunity, protecting against pathogenic microbes, and maintaining health. Remarkable new findings showed that our microbiome not only primarily affects the health and function of the gastrointestinal tract but also has a strong influence on general body health through its close interaction with the nervous system and the lung. Therefore, a perfect and sensitive balanced interaction of microbes with the host is required for a healthy body. In fact, growing evidence suggests that the dynamics and function of the indigenous microbiota can be influenced by many factors, including genetics, diet, age, and toxicological agents like cigarette smoke, environmental contaminants, and drugs. The disruption of this balance, that is called dysbiosis, is associated with a plethora of diseases, including metabolic diseases, inflammatory bowel disease, chronic obstructive pulmonary disease, periodontitis, skin diseases, and neurological disorders. The importance of the host microbiome for the human health has also led to the emergence of novel therapeutic approaches focused on the intentional manipulation of the microbiota, either by restoring missing functions or eliminating harmful roles. In the present review, we outline recent studies devoted to elucidate not only the role of microbiome in health conditions and the possible link with various types of diseases but also the influence of various toxicological factors on the microbial composition and function.