Pulmonary-intestinal cross-talk in mucosal inflammatory disease

Is the Gut Microbiome a Target for Adjuvant Treatment of COVID-19?

High expression of the transmembrane protein angiotensin I converting enzyme 2 (ACE2), more than 100-times higher as in the lung, and transmembrane serine protease 2 (TMPRSS2) in the gastrointestinal tract leads to infection with SARS-CoV-2. According to meta-analysis data, 9.8–20% of COVID-19 patients experience gastrointestinal symptoms, where diarrhoea is the most frequent, and about 50% shed viruses with high titre through their faeces, where a first faecal transmission was reported. Furthermore, gut inflammation, intestinal damage, and weakening of the gut mucosal integrity that leads to increased permeability has been shown in different studies for COVID-19 patients. This can lead to increased inflammation and bacteraemia. Low mucosal integrity combined with low intestinal damage is a good predictor for disease progression and submission to the intensive care unit (ICU). Several pilot studies have shown that the gut microbiome of COVID-19 patients is changed, microbial richness and diversity were lower, and opportunistic pathogens that can cause bacteraemia were enriched compared to a healthy control group. In a large proportion of these patients, dysbiosis was not resolved at discharge from the hospital and one study showed dysbiosis is still present after 3 months post COVID-19. Consequently, there might be a link between dysbiosis of the gut microbiome in COVID-19 patients and chronic COVID-19 syndrome (CCS). Various clinical trials are investigating the benefit of probiotics for acute COVID-19 patients, the majority of which have not reported results yet. However, two clinical trials have shown that a certain combination of probiotics is beneficial and safe for acute COVID-19 patients. Mortality was 11% for the probiotic treatment group, and 22% for the control group. Furthermore, for the probiotic group, symptoms cleared faster, and an 8-fold decreased risk of developing a respiratory failure was calculated. In conclusion, evidence is arising that inflammation, increased permeability, and microbiome dysbiosis in the gut occur in COVID-19 patients and thus provide new targets for adjuvant treatments of acute and chronic COVID-19. More research in this area is needed.

Microbiota and Its Impact on the Immune System in COVID-19-A Narrative Review

The microbiota is of interest for the development of a therapeutic strategy against SARS-CoV-2 coronavirus disease 2019 (COVID-19) due to its impact on the host immune system. Proven communications of the gut microbiota with the pulmonary microbiota (gut-lung axis) and the pathway of neural connections between the gut and brain (gut-brain axis) may be important in the face of the pandemic. SARS-CoV-2 was shown to affect almost all organs because of the presence of a host receptor known as angiotensin converting enzyme 2 (ACE2). The ACE2 receptor is mainly present in the brush border of intestinal enterocytes, ciliary cells, and type II alveolar epithelial cells in the lungs. The transport function of ACE2 has been linked to the ecology of gut microbes in the digestive tract, suggesting that COVID-19 may be related to the gut microbiota. The severity of COVID-19 may be associated with a number of comorbidities, such as hypertension, diabetes, obesity, and/or old age; therefore, attention is also paid to multiple morbidities and the modulation of microbiota through comorbidities and medications. This paper reviews the research in the context of the state of the intestinal microbiota and its impact on the cells of the immune system during the SARS-CoV-2 pandemic.

Polysaccharides from Dendrobium officinale ameliorate colitis-induced lung injury via inhibiting inflammation and oxidative stress

It has been reported that Dendrobium officinale polysaccharides (DOPS) could alleviate colitis in animal model and suppress the activation of NLRP3 inflammasome and β-arrestin1 in vitro. However, it remains unclear whether DOPS has effect on protecting against colitis-induced pulmonary injury. The purpose of this study was to explore the protective effect and mechanism of DOPS on colitis-induced lung injury. A dextran sodium sulfate (DSS)-induced mice colitis model and lipopolysaccharide (LPS)-stimulated BEAS-2B cells model were applied in this study. The results showed that DOPS treatment restored histopathological changes, reduced inflammatory cells infiltration, pro-inflammatory cytokines levels, reactive oxygen species (ROS) formation and MDA generation, and increased anti-oxidative enzymes activities including SOD and GSH-Px in colitis mice. Further investigation showed that DOPS significantly inhibited the protein expression of TLR4, and apparently up-regulated proteins expressions of nuclear-Nrf2, HO-1 and NQO-1 in lung tissues of colitis mice and in BEAS-2B cells. These results indicated that DOPS significantly inhibited inflammation and oxidative stress to alleviate colitis-induced secondary lung injury, and its mechanisms are closely related to the inhibition of TLR4 signaling pathway and the activation of Nrf2 signaling pathway. DOPS may be a promising drug for alleviating colitis-induced lung injury.

Exposure to a mixture of cigarette smoke carcinogens disturbs gut microbiota and influences metabolic homeostasis in A/J mice

An increased risk of developing lung cancer has been associated with exposure to cigarette smoke carcinogens and alteration in the gut microbiota. However, there is limited understanding about the impact of exposure to NNK and BaP, the two important components of cigarette smoke carcinogens, on gut microbiota in lung cancer. The present study characterized the influence of exposure to a mixture of NNK plus BaP on lung cancer, feces metabolite composition, and gut microbiota in the A/J mice. The A/J mice were administered NNK plus BaP, and the changes in gut microbiota and feces metabolic profiles were characterized using 16S rRNA gene sequencing and metabolomics, respectively. Results presented here illustrated that a mixture of NNK plus BaP exposure triggered lung carcinogenesis as shown by light microscopy and histopathological evaluation. 16S rRNA sequencing of gut microbiota indicated that exposure to NNK plus BaP could modified fecal bacterial composition. Elevated levels of Actinobacteria, Bifidobacterium, and Intestinimonas and reduced levels of Alistipes, Odoribacter, and Acetatifactor are associated with NNK plus BaP triggered lung cancer. In addition, metabolomics profile revealed the regulation of metabolism including purine metabolism, phenylalanine metabolism, primary bile acid biosynthesis, steroid hormone biosynthesis, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and others. In conclusion, the results provide some guidance for using gut microbes as biomarkers to assess the progression of lung cancer, and lead to interventional targets to control the development of the disease in the future.

Tying Small Changes to Large Outcomes: The Cautious Promise in Incorporating the Microbiome into Immunotherapy

The role of the microbiome in immunology is a rapidly burgeoning topic of study. Given the increasing use of immune checkpoint inhibitor (ICI) therapy in cancers, along with the recognition that carcinogenesis has been linked to dysregulations of the immune system, much attention is now directed at potentiation of ICI efficacy, as well as minimizing the incidence of treatment-associated immune-related adverse events (irAEs). We provide an overview of the major research establishing links between the microbiome to tumorigenesis, chemotherapy and radiation potentiation, and ICI efficacy and irAE development.

Work Stress, Dysbiosis, and Immune Dysregulation: The Interconnected Triad in COVID-19 Infection in the Medical Team Staff - A Mini-Review

The COVID-19 pandemic has hit most of the communities around the globe. Earlier researches have reported the psychological effects of pandemics either on the general populations or on specific communities such as students and health professionals. A scanty number of papers have focused on the interaction among complex factors underlying the pathogenesis of the disease. In this review, we aimed to integrate the accessible data about the possible mechanistic processes predisposing to COVID-19 infection in the health professions. We summarized these factors as "stress, microbiota, and immunity triad." We utilized the PubMed database, Google, and Google Scholar search engines to search the literature related to combinations of these keywords: "pandemics, COVID-19, coronavirus, SARS-CoV2;" "gut microbiota, gut-lung axis, dysbiosis, nutrition;" "work stress, workload, health workers, health professions, and medical team;" and "immunity, cytokine storm, and viral load." We detected no discussions combining the suggested triad concerning the medical team personnel. We cast light, for the first time to our knowledge, on the potential pathogenic role of "stress, microbiota, and immunity triad" in COVID-19-infected health workers.

Prospective correlation between the patient microbiome with response to and development of immune-mediated adverse effects to immunotherapy in lung cancer

BACKGROUND

Though the gut microbiome has been associated with efficacy of immunotherapy (ICI) in certain cancers, similar findings have not been identified for microbiomes from other body sites and their correlation to treatment response and immune related adverse events (irAEs) in lung cancer (LC) patients receiving ICIs.

METHODS

We designed a prospective cohort study conducted from 2018 to 2020 at a single-center academic institution to assess for correlations between the microbiome in various body sites with treatment response and development of irAEs in LC patients treated with ICIs. Patients must have had measurable disease, ECOG 0-2, and good organ function to be included. Data was collected for analysis from January 2019 to October 2020. Patients with histopathologically confirmed, advanced/metastatic LC planned to undergo immunotherapy-based treatment were enrolled between September 2018 and June 2019. Nasal, buccal and gut microbiome samples were obtained prior to initiation of immunotherapy +/- chemotherapy, at development of adverse events (irAEs), and at improvement of irAEs to grade 1 or less.

RESULTS

Thirty-seven patients were enrolled, and 34 patients were evaluable for this report. 32 healthy controls (HC) from the same geographic region were included to compare baseline gut microbiota. Compared to HC, LC gut microbiota exhibited significantly lower α-diversity. The gut microbiome of patients who did not suffer irAEs were found to have relative enrichment of Bifidobacterium (p = 0.001) and Desulfovibrio (p = 0.0002). Responders to combined chemoimmunotherapy exhibited increased Clostridiales (p = 0.018) but reduced Rikenellaceae (p = 0.016). In responders to chemoimmunotherapy we also observed enrichment of Finegoldia in nasal microbiome, and increased Megasphaera but reduced Actinobacillus in buccal samples. Longitudinal samples exhibited a trend of α-diversity and certain microbial changes during the development and resolution of irAEs.

CONCLUSIONS

This pilot study identifies significant differences in the gut microbiome between HC and LC patients, and their correlation to treatment response and irAEs in LC. In addition, it suggests potential predictive utility in nasal and buccal microbiomes, warranting further validation with a larger cohort and mechanistic dissection using preclinical models.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03688347 . Retrospectively registered 09/28/2018.

Time-resolved proteomic profiling of cigarette smoke-induced experimental chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is the third leading cause of illness and death worldwide. Current treatments aim to control symptoms with none able to reverse disease or stop its progression. We explored the major molecular changes in COPD pathogenesis.

METHODS

We employed quantitative label-based proteomics to map the changes in the lung tissue proteome of cigarette smoke-induced experimental COPD that is induced over 8 weeks and progresses over 12 weeks.

RESULTS

Quantification of 7324 proteins enabled the tracking of changes to the proteome. Alterations in protein expression profiles occurred in the induction phase, with 18 and 16 protein changes at 4- and 6-week time points, compared to age-matched controls, respectively. Strikingly, 269 proteins had altered expression after 8 weeks when the hallmark pathological features of human COPD emerge, but this dropped to 27 changes at 12 weeks with disease progression. Differentially expressed proteins were validated using other mouse and human COPD bronchial biopsy samples. Major changes in RNA biosynthesis (heterogeneous nuclear ribonucleoproteins C1/C2 [HNRNPC] and RNA-binding protein Musashi homologue 2 [MSI2]) and modulators of inflammatory responses (S100A1) were notable. Mitochondrial dysfunction and changes in oxidative stress proteins also occurred.

CONCLUSION

We provide a detailed proteomic profile, identifying proteins associated with the pathogenesis and disease progression of COPD establishing a platform to develop effective new treatment strategies.

Effect of Cigarette Smoke on Gut Microbiota: State of Knowledge

Cigarette smoke is a representative source of toxic chemical exposures to humans, and the adverse consequences of cigarette smoking are mediated by its effect on both neuronal and immune-inflammatory systems. Cigarette smoking also is a major risk factor for intestinal disorders, such as Crohn's disease and peptic ulcer. On the other hand, cigarette smoking is protective against developing ulcerative colitis. The effects of cigarette smoking on intestinal disorders include changes in intestinal irrigation and microbiome, increases in permeability of the mucosa, and impaired mucosal immune responses. However, the underlying mechanism linking cigarette smoking with intestinal microbiota dysbiosis is largely unknown. In this communication, we first review the current knowledge about the mechanistic interaction between cigarette smoke and intestinal microbiota dysbiosis, which include the likely actions of nicotine, aldehydes, polycyclic aromatic hydrocarbons, heavy metals, volatile organic compounds and toxic gases, and then reveal the potential mechanisms of the lung-gut cross talk and skin-gut cross talk in regulating the balance of intestinal microbiota and the interrelation of intestinal microbiota dysbiosis and systemic disorders.

Autoimmunity and COVID-19 - The microbiotal connection

Background and aims

The novel SARS-CoV-2 has been rattling the world since its outbreak in December 2019, leading to the COVID-19 pandemic. The learning curve of this new virus has been steep, with a global scientific community desperate to learn how the virus is transmitted, how it replicates, why it causes such a wide spectrum of disease manifestations, resulting in none or few symptoms in some. Others are burdened by an intense immune response that resembles the cytokine storm syndrome (CSS), which leads to severe disease manifestations, often complicated by fatal acute respiratory distress syndrome and death. Research efforts have been focusing on finding effective cures and vaccinations for this virus.

The presence of SARS-CoV-2 in the gastrointestinal (GI) tract, represented by several GI manifestations, has led to its investigation as a target for the virus and as an indicator of disease severity. The response of the microbiome (which is heavily linked to immunity) to the novel SARS-CoV-2 virus, and its role in igniting the exaggerated immune response has therefore become a focus of interest. The objective of our study was to gather the data connecting between the microbiome, the GI tract and COVID-19 and to investigate whether these reported alterations in the gut microbiome bear any resemblance to those seen in lupus, the prototypical autoimmune disease. Confirming such changes may become the steppingstone to potential therapies that may prevent transmission, progression and immune related manifestations of COVID-19, via manipulation of the gut microbiota.

Methods

We performed an extensive literature review, utilizing the Pubmed search engine and Google Scholar for studies evaluating the microbiome in COVID-19 patients and compared results with studies evaluating the microbiome in lupus. We searched for the terms: microbiome, dysbiosis, COVID-19, SARS-CoV-2, gastrointestinal as well as lupus and autoimmune. While there were hundreds of articles which referred to gastrointestinal manifestations in COVID-19, to date only 4 studies investigated the gastrointestinal microbiome in this setting. We compared the similarities between microbiome of COVID-19 patients and lupus patients.

Results

We found that there are several similar processes of immune dysregulation in patients with COVID-19 and in those with lupus, with several other alterations seen in other pathological states. Some of these similarities include loss of microbiota biodiversity, increased representation of pathobionts, which are microbes associated with inflammation and disease (i.e Proteobacteria) and a relative decrease of symbionts, which are protective microbes, associated with anti-inflammatory properties (i.e Lactobacillus). Compromise to the intestinal barrier has also been reported in both.

Conclusions

We conclude that the gastrointestinal tract contributes to the disease manifestations in COVID-19. Whether gastrointestinal dysbiosis is the cause or effect of gastrointestinal manifestations and several severe systemic manifestations, which may be the response to an increased pro-inflammatory environment, is still debatable and warrants further investigation. Given the resemblance of the microbiome in COVID-19 patients to that seen in lupus patients, it becomes clearer why several therapies used in autoimmune conditions are currently under investigation for the treatment of COVID-19 patients. Moreover, these findings should promote further investigating the utility of manipulation of the microbiome, via nutritional supplementation or even fecal transplantations, interventions that may alter the course of the disease, and potentially prevent disease transmission at low cost and low risk.

Acute Radiation Syndrome and the Microbiome: Impact and Review

Study of the human microbiota has been a centuries-long endeavor, but since the inception of the National Institutes of Health (NIH) Human Microbiome Project in 2007, research has greatly expanded, including the space involving radiation injury. As acute radiation syndrome (ARS) is multisystemic, the microbiome niches across all areas of the body may be affected. This review highlights advances in radiation research examining the effect of irradiation on the microbiome and its potential use as a target for medical countermeasures or biodosimetry approaches, or as a medical countermeasure itself. The authors also address animal model considerations for designing studies, and the potential to use the microbiome as a biomarker to assess radiation exposure and predict outcome. Recent research has shown that the microbiome holds enormous potential for mitigation of radiation injury, in the context of both radiotherapy and radiological/nuclear public health emergencies. Gaps still exist, but the field is moving forward with much promise.

Dietary Supplements and Nutraceuticals under Investigation for COVID-19 Prevention and Treatment

Coronavirus disease 2019 (COVID-19) has caused global disruption and a significant loss of life. Existing treatments that can be repurposed as prophylactic and therapeutic agents may reduce the pandemic's devastation. Emerging evidence of potential applications in other therapeutic contexts has led to the investigation of dietary supplements and nutraceuticals for COVID-19. Such products include vitamin C, vitamin D, omega 3 polyunsaturated fatty acids, probiotics, and zinc, all of which are currently under clinical investigation. In this review, we critically appraise the evidence surrounding dietary supplements and nutraceuticals for the prophylaxis and treatment of COVID-19. Overall, further study is required before evidence-based recommendations can be formulated, but nutritional status plays a significant role in patient outcomes, and these products may help alleviate deficiencies. For example, evidence indicates that vitamin D deficiency may be associated with a greater incidence of infection and severity of COVID-19, suggesting that vitamin D supplementation may hold prophylactic or therapeutic value. A growing number of scientific organizations are now considering recommending vitamin D supplementation to those at high risk of COVID-19. Because research in vitamin D and other nutraceuticals and supplements is preliminary, here we evaluate the extent to which these nutraceutical and dietary supplements hold potential in the COVID-19 crisis.IMPORTANCE Sales of dietary supplements and nutraceuticals have increased during the pandemic due to their perceived "immune-boosting" effects. However, little is known about the efficacy of these dietary supplements and nutraceuticals against the novel coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) or the disease that it causes, CoV disease 2019 (COVID-19). This review provides a critical overview of the potential prophylactic and therapeutic value of various dietary supplements and nutraceuticals from the evidence available to date. These include vitamin C, vitamin D, and zinc, which are often perceived by the public as treating respiratory infections or supporting immune health. Consumers need to be aware of misinformation and false promises surrounding some supplements, which may be subject to limited regulation by authorities. However, considerably more research is required to determine whether dietary supplements and nutraceuticals exhibit prophylactic and therapeutic value against SARS-CoV-2 infection and COVID-19. This review provides perspective on which nutraceuticals and supplements are involved in biological processes that are relevant to recovery from or prevention of COVID-19.

The Role of Microbiome and Virome in Idiopathic Pulmonary Fibrosis

The interest in the lung microbiome and virome and their contribution to the pathogenesis, perpetuation and progression of idiopathic pulmonary fibrosis (IPF) has been increasing during the last decade. The utilization of high-throughput sequencing to detect microbial and/or viral genetic material in bronchoalveolar lavage fluid or lung tissue samples has amplified the ability to identify and quantify specific microbial and viral populations. In stable IPF, higher microbial burden is associated with worse prognosis but no specific microbe has been identified to contribute to this. Additionally, no causative relation has been established. Regarding viral infections, although in the past they have been associated with IPF, causation has not been proved. Although in the past the diagnosis of acute exacerbation of IPF (AE-IPF) was not considered in patients with overt infection, this was amended in the last few years and infection is considered a cause for exacerbation. Besides this, a higher microbial burden has been found in the lungs of patients with AE-IPF and an association with higher morbidity and mortality has been confirmed. In contrast, an association of AE-IPF with viral infection has not been established. Despite the progress during the last decade, a comprehensive knowledge of the microbiome and virome in IPF and their role in disease pathogenesis are yet elusive. Although association with disease severity, risk for progression and mortality has been established, causation has not been proven and the potential use as a biomarker or the benefits of antimicrobial therapeutic strategies are yet to be determined.

Global prevalence of prolonged gastrointestinal symptoms in COVID-19 survivors and potential pathogenesis: A systematic review and meta-analysis

Background: This study aimed to determine the cumulative prevalence of prolonged gastrointestinal (GI) symptoms, including nausea, vomiting, diarrhea, lack of appetite, abdominal pain, and dysgeusia, in survivors of both mild and severe COVID-19 worldwide and to discuss the potential pathogenesis.   Methods: Three databases (PubMed, Scopus, and Web of Science) were searched for relevant articles up to January 30, 2021. Data on study characteristics, clinical characteristics during follow-up, the number of patients with prolonged GI symptoms, and total number of COVID-19 survivors were retrieved according to PRISMA guidelines. The quality of eligible studies was assessed using the Newcastle-Ottawa scale. The pooled prevalence of specific prolonged GI symptoms was calculated and the association between COVID-19 severity and the occurrence of prolonged GI symptoms was assessed if appropriate.   Results: The global prevalence of prolonged nausea was 3.23% (95% CI: 0.54%-16.53%) among 527 COVID-19 survivors. Vomiting persisted in 93 of 2,238 COVID-19 survivors (3.19%, 95% CI: 1.62%-6.17%) and prolonged diarrhea was found in 34 of 1,073 survivors (4.12%, 95% CI: 1.07%-14.64%). A total of 156 patients among 2,238 COVID-19 survivors (4.41%, 95% CI: 1.91%-9.94%) complained of persistent decreased or loss of appetite. The cumulative prevalence of prolonged abdominal pain was 1.68% (95% CI: 0.84%-3.32%), whereas persistent dysgeusia was identified in 130 cases among 1,887 COVID-19 survivors (7.04%, 95% CI: 5.96%-8.30%). Data was insufficient to assess the relationship between COVID-19 severity and the occurrence of all prolonged GI symptoms.   Conclusion: Persistent GI symptoms among COVID-19 survivors after discharge or recovery raises a concern regarding the long-term impact of the COVID-19 infection on the quality of life of the survivors. Despite several potential explanations proposed, studies that aim to follow patients after recovery from COVID-19 and determine the pathogenesis of the prolonged symptoms of COVID-19 survivors are warranted.   PROSPERO registration: CRD42021239187.

Probiotics/ prebiotics in viral respiratory infections: implication for emerging pathogens

BACKGROUND

Viral respiratory infections could result in perturbation of the gut microbiota due to a probable cross-talk between lungs and gut microbiota. This can affect the pulmonary health and the gastrointestinal system.

OBJECTIVE

This review aimed to discuss the impact of probiotics/ prebiotics and supplements on the prevention and treatment of respiratory infections, especially emerging pathogens.

METHODS

The data were searched were searched in PubMed, Scopus, Google Scholar, Google Patents, and The Lens-Patent using keywords of probiotics and viral respiratory infections in the title, abstract, and keywords.

RESULT

Probiotics consumption could decrease the susceptibility to viral respiratory infections, such as COVID-19 and simultaneously enhance vaccine efficiency in infectious disease prevention through the immune system enhancement. Probiotics improve the gut microbiota and the immune system via regulating the innate system response and production of anti-inflammatory cytokines. Moreover, treatment with probiotics contributes to the intestinal homeostasis restitution under antibiotic pressure and decreasing the risk of secondary infections due to viral respiratory infections. Probiotics present varied performances in different conditions; thus, promoting their efficacy through combining with supplements (prebiotics, postbiotics, nutraceuticals, berberine, curcumin, lactoferrin, minerals, and vitamins) is important. Several supplements reported to enhance the probiotics' efficacy and their mechanisms as well as probiotics related patents are summarized in this review. Using nanotechnology and microencapsulation techniques can also improve probiotics efficiency.

CONCLUSION

Given the global challenge of COVID-19, probiotic/prebiotic and following nutritional guidelines should be regarded seriously. Additionally, their role as an adjuvant in vaccination for immune response augmentation needs attention.

The gut microbiome: a missing link in understanding the gastrointestinal manifestations of COVID-19?

Coronavirus disease 2019 (COVID-19), which is caused by infection with SARS-CoV-2, presents with a broad constellation of both respiratory and nonrespiratory symptoms, although it is primarily considered a respiratory disease. Gastrointestinal symptoms-including nausea, abdominal pain, vomiting, and diarrhea-rank chief among these. When coupled with the presence of viral RNA in fecal samples, the presence of gastrointestinal symptoms raises relevant questions regarding whether SARS-CoV-2 can productively infect the upper or lower gastrointestinal tract. Despite the well-documented prevalence of gastrointestinal symptoms and the high rate of SARS-CoV-2 fecal RNA shedding, the biological, clinical, and epidemiological relevance of these findings is unclear. Furthermore, the isolation of replication-competent virus from fecal samples has not been reproducibly and rigorously demonstrated. Although SARS-CoV-2 shedding likely occurs in a high proportion of patients, gastrointestinal symptoms affect only a subset of individuals. Herein, we summarize what is known about gastrointestinal symptoms and fecal viral shedding in COVID-19, explore the role of the gut microbiome in other respiratory diseases, speculate on the role of the gut microbiota in COVID-19, and discuss potential future directions. Taking these concepts together, we propose that studying gut microbiota perturbations in COVID-19 will enhance our understanding of the symptomology and pathophysiology of this novel devastating disease.

Pulmonary Manifestations of Inflammatory Bowel Disease

The frequency of extraintestinal manifestations of inflammatory bowel disease (IBD) is observed in most of the patients. Extraintestinal manifestations of IBD have been implicated in all the anatomic sites of the pulmonary tree, and include airway inflammation of the bronchi and bronchioles and parenchymal inflammation. There is a wide range of pulmonary manifestations in IBD, and most of them look a lot like other diseases. Doctors should keep a track of these conditions to avoid unnecessary complications and to provide an early diagnosis with correct and efficient treatment. IBD-related respiratory disorders are treated depending on the patient, but in most of them, steroids are generally chosen first. Steroids, both inhalational and systemic, are the primary approach. Antibiotics could also be given if the patient has infections or suppuration, usually followed by surgeries. However, drug-induced complications and toxicity should be kept in mind.

Plasma Biomarkers of Risk of Tuberculosis Recurrence in HIV Co-Infected Patients From South Africa

There is an urgent need to identify immunological markers of tuberculosis (TB) risk in HIV co-infected individuals. Previously we have shown that TB recurrence in HIV co-infected individuals on ART was associated with markers of systemic inflammation (IL-6, IL1β and IL-1Rα). Here we examined the effect of additional acute inflammation and microbial translocation marker expression on risk of TB recurrence. Stored plasma samples were drawn from the TB Recurrence upon Treatment with HAART (TRuTH) study, in which individuals with previously treated pulmonary TB were screened for recurrence quarterly for up to 4 years. Recurrent TB cases (n = 37) were matched to controls (n = 102) by original trial study arm assignment and ART start date. Additional subsets of HIV infected (n = 41) and HIV uninfected (n = 37) individuals from Improving Recurrence Success (IMPRESS) study were sampled at active TB and post successful treatment completion. Plasma concentrations of soluble adhesion molecules (sMAdCAM, sICAM and sVCAM), lipopolysaccharide binding protein (LBP) and transforming growth factor-beta (TGF-β1, TGF-β2, TGF-β3) were measured by multiplex immunoassays and ELISA. Cytokine data was square root transformed in order to reduce variability. Multivariable analysis adjusted for a number of potential confounders measured at sample time-point: age, BMI, CD4 count, viral load (VL) and measured at baseline: presence or absence of lung cavities, previous history of TB, and WHO disease stage (4 vs 3). The following analytes were associated with increased risk of TB recurrence in the multivariable model: sICAM (aOR 1.06, 95% CI: 1.02-1.12, p = 0.009), LBP (aOR 8.78, 95% CI: 1.23-62.66, p = 0.030) and TGF-β3 (aOR 1.44, 95% CI 1.01-2.05, p = 0.044). Additionally, we observed a positive correlation between LBP and sICAM (r= 0.347, p<0.0001), and LBP and IL-6, identified to be one of the strongest predictors of TB risk in our previous study (r=0.623, p=0.03). These data show that increased risk of TB recurrence in HIV infected individuals on ART is likely associated with HIV mediated translocation of microbial products and the resulting chronic immune activation.

Therapeutic targets in lung tissue remodelling and fibrosis

Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-β induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.

Next-Generation Sequencing Reveals the Progression of COVID-19

The novel coronavirus SARS-CoV-2 (causing the disease COVID-19) has caused a highly transmissible and ongoing pandemic worldwide. Due to its rapid development, next-generation sequencing plays vital roles in many aspects. Here, we summarize the current knowledge on the origin and human transmission of SARS-CoV-2 based on NGS analysis. The ACE2 expression levels in various human tissues and relevant cells were compared to provide insights into the mechanism of SAS-CoV-2 infection. Gut microbiota dysbiosis observed by metagenome sequencing and the immunogenetics of COVID-19 patients according to single-cell sequencing analysis were also highlighted. Overall, the application of these sequencing techniques could be meaningful for finding novel intermediate SARS-CoV-2 hosts to block interspecies transmission. This information will further benefit SARS-CoV-2 diagnostic development and new therapeutic target discovery. The extensive application of NGS will provide powerful support for our fight against future public health emergencies.

Impact of diet and the bacterial microbiome on the mucous barrier and immune disorders

The prevalence of chronic immune and metabolic disorders is increasing rapidly. In particular, inflammatory bowel diseases, obesity, diabetes, asthma and chronic obstructive pulmonary disease have become major healthcare and economic burdens worldwide. Recent advances in microbiome research have led to significant discoveries of associative links between alterations in the microbiome and health, as well as these chronic supposedly noncommunicable, immune/metabolic disorders. Importantly, the interplay between diet, microbiome and the mucous barrier in these diseases has gained significant attention. Diet modulates the mucous barrier via alterations in gut microbiota, resulting in either disease onset/exacerbation due to a "poor" diet or protection against disease with a "healthy" diet. In addition, many mucosa-associated disorders possess a specific gut microbiome fingerprint associated with the composition of the mucous barrier, which is further influenced by host-microbiome and inter-microbial interactions, dietary choices, microbe immigration and antimicrobials. Our review focuses on the interactions of diet (macronutrients and micronutrients), gut microbiota and mucous barriers (gastrointestinal and respiratory tract) and their importance in the onset and/or progression of major immune/metabolic disorders. We also highlight the key mechanisms that could be targeted therapeutically to prevent and/or treat these disorders.

The Impact of SARS-CoV-2 on the Human Immune System and Microbiome

A recent outbreak of coronavirus disease 2019 (COVID-19) caused by the single-stranded enveloped RNA virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has developed into a global pandemic, after it was first reported in Wuhan in December 2019. SARS-CoV-2 is an emerging virus, and little is known about the basic characteristics of this pathogen, the underlying mechanism of infection, and the potential treatments. The immune system has been known to be actively involved in viral infections. To facilitate the development of COVID-19 treatments, the understanding of immune regulation by this viral infection is urgently needed. This review describes the mechanisms of immune system involvement in viral infections and provides an overview of the dysregulation of immune responses in COVID-19 patients in recent studies. Furthermore, we emphasize the role of gut microbiota in regulating immunity and summarized the impact of SARS-CoV-2 infection on the composition of the microbiome. Overall, this review provides insights for understanding and developing preventive and therapeutic strategies by regulating the immune system and microbiota.

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.

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.

Dietary Supplements and Nutraceuticals Under Investigation for COVID-19 Prevention and Treatment

Coronavirus disease 2019 (COVID-19) has caused global disruption and a significant loss of life. Existing treatments that can be repurposed as prophylactic and therapeutic agents could reduce the pandemic's devastation. Emerging evidence of potential applications in other therapeutic contexts has led to the investigation of dietary supplements and nutraceuticals for COVID-19. Such products include vitamin C, vitamin D, omega 3 polyunsaturated fatty acids, probiotics, and zinc, all of which are currently under clinical investigation. In this review, we critically appraise the evidence surrounding dietary supplements and nutraceuticals for the prophylaxis and treatment of COVID-19. Overall, further study is required before evidence-based recommendations can be formulated, but nutritional status plays a significant role in patient outcomes, and these products could help alleviate deficiencies. For example, evidence indicates that vitamin D deficiency may be associated with greater incidence of infection and severity of COVID-19, suggesting that vitamin D supplementation may hold prophylactic or therapeutic value. A growing number of scientific organizations are now considering recommending vitamin D supplementation to those at high risk of COVID-19. Because research in vitamin D and other nutraceuticals and supplements is preliminary, here we evaluate the extent to which these nutraceutical and dietary supplements hold potential in the COVID-19 crisis.

Gut microbiota influence tumor development and Alter interactions with the human immune system

Recent scientific advances have greatly enhanced our understanding of the complex link between the gut microbiome and cancer. Gut dysbiosis is an imbalance between commensal and pathogenic bacteria and the production of microbial antigens and metabolites. The immune system and the gut microbiome interact to maintain homeostasis of the gut, and alterations in the microbiome composition lead to immune dysregulation, promoting chronic inflammation and development of tumors. Gut microorganisms and their toxic metabolites may migrate to other parts of the body via the circulatory system, causing an imbalance in the physiological status of the host and secretion of various neuroactive molecules through the gut-brain axis, gut-hepatic axis, and gut-lung axis to affect inflammation and tumorigenesis in specific organs. Thus, gut microbiota can be used as a tumor marker and may provide new insights into the pathogenesis of malignant tumors.

Acidic Calcium-Independent Phospholipase A2 Regulates Eosinophil-Mediated Pathology during Filarial Manifestation of Tropical Pulmonary Eosinophilia

Eosinophils mediate pathological manifestations during tropical pulmonary eosinophilia (TPE), a potentially fatal complication of lymphatic filariasis, by mechanisms that are incompletely understood. Using two-dimensional gel electrophoresis, mass spectrometry, flow cytometry, and pharmacological and functional studies, we identified acidic calcium-independent phospholipase A2 (aiPLA2) as the master regulator of TPE pathogenesis. FACS-sorted lung eosinophils from TPE mice exhibited aiPLA2-dependent activation characterized by heavy calcium influx, F-actin polymerization, increased degranulation, and heightened reactive oxygen species generation. Interestingly, aiPLA2 also promoted alternative activation in lung macrophages and regulated the release of inflammatory intermediates from them. Treatment of TPE mice with MJ33, a nontoxic pharmacological inhibitor of aiPLA2, lowered eosinophil counts in the bronchoalveolar lavage fluid, reduced eosinophil peroxidase and β-hexosaminidase activity, increased airway width, improved lung endothelial barrier, and lowered the production of inflammatory lipid intermediates, which significantly improved the pathological condition of the lungs. Importantly, ex vivo reconstitution of arachidonic acid to eosinophils from MJ33-treated TPE mice increased eosinophil degranulation and inflammatory lipid intermediates underlining the pivotal role of aiPLA2 in arachidonic acid metabolism. Mechanistically, phosphorylation of JNK-1 regulated phospholipase activity of aiPLA2, whereas IgG cross-linking mediated pathological activation of eosinophils. Taken together, ours is the first study, to our knowledge, to report hitherto undocumented role of aiPLA2 in regulating TPE pathogenesis.

The relevance of nutrition as a step forward to combat COVID-19

A new type of single-stranded RNA virus that belongs to the coronavirus’s family named SARS-CoV-2 has recently appeared, with fast-growing human to human transmissions. This virus has posed an important global health threat. Many nutrients can support the immune system and help in preventing or in ameliorating the response to viral infections. In the case of COVID-19, the unique pathophysiology of the coronavirus needs to be understood, in order to determine whether any potential nutrition intervention is indicated. A literature survey that comprised of ongoing research was conducted to evaluate the benefits of the bioactives present in food, such as: plant-derived extracts, vitamins, minerals, probiotics, and prebiotics, against the mechanisms of the COVID-19 infection. Although no food is yet confirmed to help in the prevention or in the treatment of the coronavirus transmission alone, exploring the possible implications of nutrition-infection interrelationships is of utmost importance. Well-designed and controlled clinical studies are emerging to explain whether the higher consumption of fruits, vegetables, protein-rich foods, unsaturated fatty acids, and other natural functional foods may aid in combating the COVID-19 infection. Meanwhile, a healthy and balanced diet is traditionally practised in viral infections that support the healthy gut microbiota profile. The human immune system function should be a vital prophylactic measure, along with adequate physical activities and sleeping habits. The consumption of immune-supportive nutrients is also encouraged in the elderly, comorbid, and in the immune-compromised as well as in malnourished individuals, in order to minimise the complications and the negative outcomes that are associated with the COVID-19 disease. Keywords: COVID-19 nutrition, mаcronutrients, micronutrients, bioactive compounds, malnutrition

Comparison of allergenicity among cow, goat, and horse milks using a murine model of atopy

Due to the prevalence and severity of cow milk (CM) allergy (CMA), an ideal substitute is urgently needed to develop hypoallergenic infant formula for infants who experience anaphylaxis to typical whey-based CM formula. Goat milk (GM) and horse milk (HM) are considered appropriate substitutes; however, whether GM and HM are less allergenic than CM is unclear. In the present study, the difference in allergenicity among CM, GM, and HM was investigated using the Balb/c mouse model. The number of mice with severe respiratory symptoms was significantly lower in the GM- and HM-sensitised groups than in the CM-sensitised group. Furthermore, histologic examination of intestinal and lung tissues revealed a thinner lamina propria of the small intestine and obvious inflammation and congestion in lungs in the CM-sensitised group than in the GM- and HM-sensitised groups. CM-specific immunoglobulin (Ig) E, serum IgG1, and plasma histamine levels were also higher in CM-sensitised mice than in GM- or HM-sensitised mice. In addition, higher interleukin (IL) 4 and IL-17A levels and lower interferon-γ (IFN-γ) and IL-10 levels were observed in CM-sensitised mice compared with GM- and HM-sensitised mice, according to qPCR, indicating Th1/Th2 and Treg/Th17 imbalances. The CM-sensitised group had a higher proportion of IL-4- and IL-17A-producing CD3+ T cells but a lower proportion of IFN-γ- and IL-10-producing CD3+ T cells compared with the GM- and HM-sensitised groups, confirming the Th1/Th2 and Treg/Th17 imbalances. In conclusion, GM and HM were less allergenic than CM in mice as a result of a shift in the Th1/Th2 and Treg/Th17 imbalances; however, HM was less allergenic than GM and can be used as an alternative milk to develop infant formulas for children with CMA.

Exposure to the gut microbiota from cigarette smoke-exposed mice exacerbates cigarette smoke extract-induced inflammation in zebrafish larvae

Cigarette smoke (CS)-induced inflammation leads to a range of diseases including chronic obstructive pulmonary disease and cancer. The gut microbiota is a major modifying environmental factor that determine the severity of cigarette smoke-induced pathology. Microbiomes and metabolites from CS-exposed mice exacerbate lung inflammation via the gut-lung axis of shared mucosal immunity in mice but these systems are expensive to establish and analyse. Zebrafish embryos and larvae have been used to model the effects of cigarette smoking on a range of physiological processes and offer an amenable platform for screening modifiers of cigarette smoke-induced pathologies with key features of low cost and rapid visual readouts. Here we exposed zebrafish larvae to cigarette smoke extract (CSE) and characterised a CSE-induced leukocytic inflammatory phenotype with increased neutrophilic and macrophage inflammation in the gut. The CSE-induced phenotype was exacerbated by co-exposure to microbiota from the faeces of CS-exposed mice, but not control mice. Microbiota could be recovered from the gut of zebrafish and studied in isolation in a screening setting. This demonstrates the utility of the zebrafish-CSE exposure platform for identifying environmental modifiers of cigarette smoking-associated pathology and demonstrates that the CS-exposed mouse gut microbiota potentiates the inflammatory effects of CSE across host species.

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Zebrafish larvae develop gut inflammation in response to cigarette smoke exposure.

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The zebrafish larval cigarette smoke-induced inflammatory response is dose dependent.

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Microbiota from smoking mice potentiates smoke-induced inflammation in zebrafish.

SARS-CoV-2 microbiome dysbiosis linked disorders and possible probiotics role

In December 2019, a pneumonia outbreak of unknown etiology was reported which caused panic in Wuhan city of central China, which was later identified as Coronavirus disease (COVID-19) caused by a novel coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by the Chinese Centre for Disease Control and Prevention (CDC) and WHO. To date, the SARS-CoV-2 spread has already become a global pandemic with a considerable death toll. The associated symptoms of the COVID-19 infection varied with increased inflammation as an everyday pathological basis. Among various other symptoms such as fever, cough, lethargy, gastrointestinal (GI) symptoms included diarrhea and IBD with colitis, have been reported. Currently, there is no sole cure for COVID-19, and researchers are actively engaged to search out appropriate treatment and develop a vaccine for its prevention. Antiviral for controlling viral load and corticosteroid therapy for reducing inflammation seems to be inadequate to control the fatality rate. Based on the available related literature, which documented GI symptoms with diarrhea, inflammatory bowel diseases (IBD) with colitis, and increased deaths in the intensive care unit (ICU), conclude that dysbiosis occurs during SARS-COV-2 infection as the gut-lung axis cannot be ignored. As probiotics play a therapeutic role for GI, IBD, colitis, and even in viral infection. So, we assume that the inclusion of studies to investigate gut microbiome and subsequent therapies such as probiotics might help decrease the inflammatory response of viral pathogenesis and respiratory symptoms by strengthening the host immune system, amelioration of gut microbiome, and improvement of gut barrier function.

Social and Psychophysiological Consequences of the COVID-19 Pandemic: An Extensive Literature Review

The Coronavirus Disease 2019 (COVID-19) pandemic, now a global health crisis, has surprised health authorities around the world. Recent studies suggest that the measures taken to curb the spread of the COVID-19 outbreak have generated issues throughout the population. Thus, it is necessary to establish and identify the possible risk factors related to the psychosocial and psychophysiological strain during the COVID-19 outbreak. The present extensive literature review assesses the social, psychological, and physiological consequences of COVID-19, reviewing the impact of quarantine measures, isolation, vast human loss, social and financial consequences in the family's economies, and its impact on the psychological health of the population. We also discussed the effect of psychophysiological factors, considering the impact of physical inactivity and modifications in nutritional habits, at psychological and physiological levels. The present review includes an actualized to date bibliography, articles for which were methodologically analyzed to verify they met the standards of quality and scientific accuracy. Authors understand the pandemic as a multifactorial event for which only a profound and extensive analysis would lead to better compression and efficient intervention in the near future.

Gut Microbiota Status in COVID-19: An Unrecognized Player?

Infection with the SARS-CoV-2 virus causes cardiopulmonary and vascular complications, ranging in severity. Understanding the pathogenic mechanisms of the novel SARS-CoV2 infection and progression can provide potential novel targets for its prevention and/or treatment. Virus microbiota reciprocal interactions have been studied in a variety of viral infections. For example, the integrity of Coronavirus particles can be disrupted by surfactin, a bacterial surface molecule that targets other viruses, including that of influenza A. In this light, intestinal microbiota likely influences COVID-19 virulence, while from its side SARS-CoV-2 may affect the intestinal microbiome promoting dysbiosis and other deleterious consequences. Hence, the microbiota pre-existing health status and its alterations in the course of SARS-CoV-2 infection, are likely to play an important, still underscored role in determining individual susceptibility and resilience to COVID-19. Indeed, the vast majority of COVID-19 worst clinical conditions and fatalities develop in subjects with specific risk factors such as aging and the presence of one or more comorbidities, which are intriguingly characterized also by unhealthy microbiome status. Moreover, these comorbidities require complex pharmacological regimens known as "polypharmacy" that may further affect microbiota integrity and worsen the resilience to viral infections. This complex situation may represent a further and underestimated risk with regard to COVID-19 clinical burden for the elderly and comorbid people. Here, we discuss the possible biological, physiopathological, and clinical implications of gut microbiota in COVID-19 and the strategies to improve/maintain its healthy status as a simple and adjunctive strategy to reduce COVID-19 virulence and socio-sanitary burden.

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.

Human β-defensin-2 suppresses key features of asthma in murine models of allergic airways disease

BACKGROUND

Asthma is an airway inflammatory disease and a major health problem worldwide. Anti-inflammatory steroids and bronchodilators are the gold-standard therapy for asthma. However, they do not prevent the development of the disease, and critically, a subset of asthmatics are resistant to steroid therapy.

OBJECTIVE

To elucidate the therapeutic potential of human β-defensins (hBD), such as hBD2 mild to moderate and severe asthma.

METHODS

We investigated the role of hBD2 in a steroid-sensitive, house dust mite-induced allergic airways disease (AAD) model and a steroid-insensitive model combining ovalbumin-induced AAD with C muridarum (Cmu) respiratory infection.

RESULTS

In both models, we demonstrated that therapeutic intranasal application of hBD2 significantly reduced the influx of inflammatory cells into the bronchoalveolar lavage fluid. Furthermore, key type 2 asthma-related cytokines IL-9 and IL-13, as well as additional immunomodulating cytokines, were significantly decreased after administration of hBD2 in the steroid-sensitive model. The suppression of inflammation was associated with improvements in airway physiology and treatment also suppressed airway hyper-responsiveness (AHR) in terms of airway resistance and compliance to methacholine challenge.

CONCLUSIONS AND CLINICAL RELEVANCE

These data indicate that hBD2 reduces the hallmark features and has potential as a new therapeutic agent in allergic and especially steroid-resistant asthma.

Newly Reported Studies on the Increase in Gastrointestinal Symptom Prevalence withCOVID-19 Infection: A Comprehensive Systematic Review and Meta-Analysis

BACKGROUND AND AIM

Although constitutional and respiratory symptoms such as cough and fever are the most common symptoms in patients infected with COVID-19, gastrointestinal (GI) tract involvement has been observed by endoscopic biopsies. Multiple GI symptoms, including diarrhea, nausea or vomiting and abdominal pain, have also been reported. This review aims to present the currently available data regarding the GI symptoms of COVID-19 patients, and to compare the frequency of GI symptoms in early stage (Eastern) mostly Chinese data to the current stage (Western) non-Chinese data.

METHODS

We performed a systematic literature search to identify both published studies by using PubMed, Google Scholar, and CNKI (Chinese medical search engine), and yet unpublished studies through medRxiv and bioRxiv. We also reviewed the cross references of the detected articles. We conducted a Medical Subject Headings (MeSH) search up until 20 September 2020. We pooled the prevalence of symptoms of diarrhea, anorexia, nausea, vomiting, and abdominal pain by using the Freeman-Tukey's transforming random effect model.

RESULTS

A total of 118 studies were included in the systematic review and 44 of them were included in the meta-analysis. There was a significant heterogeneity between the studies; therefore, the random effects model was used. The pooled prevalence estimate of any GI symptoms reported was found to be 0.21 (95%CI, 0.16-0.27). Anorexia was the most commonly reported GI symptom at 18% (95%CI, 0.10-0.27) followed by diarrhea at 15% (95%CI, 0.12-0.19). Diarrhea, abdominal pain, nausea/vomiting, and respiratory symptoms were more common in non-Chinese studies. The prevalence of abdominal pain was lower in the "inpatient-only" studies when compared with studies that included outpatients only and those including both inpatients and outpatients.

CONCLUSIONS

In this comprehensive systematic review and meta-analysis study, we observed higher rates of diarrhea, nausea/vomiting, and abdominal pain in COVID-19 infected patients among non-Chinese studies compared to Chinese studies. We also observed a higher prevalence of GI symptoms in Chinese studies than was reported previously. Non-respiratory symptoms, including GI tract symptoms, should be more thoroughly and carefully evaluated and reported in future studies.

Variations in fecal microbial profiles of acute exacerbations and stable chronic obstructive pulmonary disease

AIM

Alterations in the respiratory and digestive tract microbiomes influence the occurrence and progression of chronic obstructive pulmonary disease (COPD). Here, we aimed to identify fecal microbiome profiles during COPD development.

METHODS

Fecal samples were collected from 29 COPD patients with acute exacerbation (AECOPD), 29 stable COPD patients, and 22 normal subjects (NS). The fecal microbial profiles were obtained using 16S rRNA gene sequencing.

KEY FINDINGS

The diversity and richness were lower and fewer variations in the taxonomic composition of fecal microbiota were observed in AECOPD patients than in stable COPD and NS. The relative abundances of Firmicutes and Actinobacteria were decreased, while those of Bacteroidetes and Proteobacteria were increased in AECOPD compared to COPD and NS. Among the top ten genera, the proportions of Lachnoclostridium and Parabacteroides significantly increased in AECOPD, whereas those of other genera decreased. Discriminative bacteria, such as p_Bacteroidetes, c_Bacteroidia, o_Bacteroidales, Lactobacillales, and Proteobacteria, were identified in AECOPD compared to stable COPD and NS. The weighted gene co-expression networks showed that Firmicutes and Actinobacteria were the main hub bacterial taxa related with lung function (FEV1% and FEV1/FVC%) and inflammatory indices (TNF-α, IL-6, IL-8, PCT, and CRP).

SIGNIFICANCE

These findings emphasized the changes in the abundance and composition of the fecal microbiome in stable COPD and AECOPD. Variations in fecal microbiota may be associated with COPD progression.

Effect of probiotics, prebiotics and synbiotics for chronic bronchitis or chronic obstructive pulmonary disease: A protocol for systematic review and meta-analysis

BACKGROUND

Probiotics, prebiotics and synbiotics have been widely used in the treatment of respiratory diseases, but their clinical efficacy for treating chronic bronchitis (CB) or chronic obstructive pulmonary disease (COPD) has not been well studied.

METHODS

The following electronic databases will be searched for eligible randomized controlled trials: the Cochrane Library, EMBASE, MEDLINE, PubMed, Scopus, the Web of Science, the China National Knowledge Infrastructure, the Wanfang database, and the China Science and Technology Journal database (VIP Information Network). We will search these electronic databases weekly and extract relevant data from their inception dates until September 30, 2020. Risk of publication bias will be evaluated by the Cochrane Handbook for Systematic Reviews of Interventions. Data synthesis will be conducted using Review Manager (RevMan) version 5.3 software. Sensitivity and quality of evidence analyses will be conducted.

RESULTS

This systematic review and meta-analysis will provide a high-quality synthesis from existing evidence for estimating the efficacy and safety of probiotics, prebiotics and synbiotics in the treatment of CB or COPD.

CONCLUSION

This systematic review and meta-analysis will provide reliable and accurate evidence to guide the use of probiotics, prebiotics and synbiotics in the treatment of CB or COPD.

REGISTRATION OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/SP35M.

Impact of Gastrointestinal Symptoms in COVID-19: a Molecular Approach

The pandemic of novel coronavirus disease (COVID-19) caused by the Severe Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) creates an immense menace to public health worldwide. Currently, the World Health Organization (WHO) has recognized the novel coronavirus as the main cause of global pandemic. Patients infected with this virus generally show fever, nausea, and respiratory illness, while some patients also manifest gastrointestinal symptoms such as abdominal pain, vomiting, and diarrhea. Traces of SARS-CoV-2 RNA have been found in gastrointestinal cells. Further angiotensin converting enzyme 2 (ACE2) the known receptor for the virus is extensively expressed in these cells. This implies that gastrointestinal tract can be infected and can also present them as a replication site for SARS-CoV-2, but since this infection may lead to multiple organ failure, therefore identification of another receptor is a plausible choice. This review aims to provide comprehensive information about probable receptors such as sialic acid and CD147 which may facilitate the virus entry. Several potential targets are mentioned which can be used as a therapeutic approach for COVID-19 and associated GI disorders. The gut microbiomes are responsible for high levels of interferon-gamma which causes hyper-inflammation and exacerbates the severity of the disease. Briefly, this article highlights the gut microbiome’s relation and provides potential diagnostic approaches like RDT and LC-MS for sensitive and specific identification of viral proteins. Altogether, this article reviews epidemiology, probable receptors and put forward the tentative ideas of the therapeutic targets and diagnostic methods for COVID-19 with gastrointestinal aspect of disease.

Probiotics in Treatment of Viral Respiratory Infections and Neuroinflammatory Disorders

Inflammation is a biological response to the activation of the immune system by various infectious or non-infectious agents, which may lead to tissue damage and various diseases. Gut commensal bacteria maintain a symbiotic relationship with the host and display a critical function in the homeostasis of the host immune system. Disturbance to the gut microbiota leads to immune dysfunction both locally and at distant sites, which causes inflammatory conditions not only in the intestine but also in the other organs such as lungs and brain, and may induce a disease state. Probiotics are well known to reinforce immunity and counteract inflammation by restoring symbiosis within the gut microbiota. As a result, probiotics protect against various diseases, including respiratory infections and neuroinflammatory disorders. A growing body of research supports the beneficial role of probiotics in lung and mental health through modulating the gut-lung and gut-brain axes. In the current paper, we discuss the potential role of probiotics in the treatment of viral respiratory infections, including the COVID-19 disease, as major public health crisis in 2020, and influenza virus infection, as well as treatment of neurological disorders like multiple sclerosis and other mental illnesses.

Clinical Features and Outcomes of Tuberculosis in Inflammatory Bowel Disease Patients Treated with Anti-tumor Necrosis Factor Therapy

Background/Aims

Anti-tumor necrosis factor (TNF) therapy is used widely for the treatment of inflammatory bowel disease (IBD). In the present study, the characteristics and outcomes of tuberculosis (TB) in IBD patients treated with anti-TNF therapy were compared with those of non-IBD TB patients.

Methods

Twenty-five IBD patients who initially developed TB during anti-TNF therapy were enrolled in this study. Seventy-five ageand gender-matched non-IBD TB patients were selected as controls in a 1:3 ratio.

Results

The proportion of non-respiratory symptoms was higher in the IBD patients than in the non-IBD patients (12 [48.0%] in the IBD patients vs. 15 [20.0%] in the non-IBD patients; p=0.009). Eight (32.0%) IBD patients and 19 (25.3%) non-IBD patients had extra- pulmonary lesions (p=0.516). The frequency of positive smear results for acid-fast bacilli (AFB) was significantly higher in the non-IBD patients than in the IBD patients (three [12.0%] IBD patients vs. 27 [36.0%] non-IBD patients; p=0.023). Active TB was cured in 24 (96.0%) patients in the IBD group and in 70 (93.3%) patients in the non-IBD group (p=0.409). The TB-related mortality rates were 4.0% and 1.3% in the IBD patients and non-IBD patients, respectively (p=0.439).

Conclusions

The rate of extrapulmonary involvement, side effects of anti-TB medications, and clinical outcomes did not differ between the IBD patients who initially developed TB during anti-TNF therapy and non-IBD patients with TB. On the other hand, the IBD patients had a lower rate of AFB smear positivity and a higher proportion of non-respiratory symptoms.

Age-related changes in intestinal immunity and the microbiome

The gastrointestinal (GI) tract is a vitally important site for the adsorption of nutrients as well as the education of immune cells. Homeostasis of the gut is maintained by the interplay of the intestinal epithelium, immune cells, luminal Ags, and the intestinal microbiota. The well-being of the gut is intrinsically linked to the overall health of the host, and perturbations to this homeostasis can have severe impacts on local and systemic health. One factor that causes disruptions in gut homeostasis is age, and recent research has elucidated how critical systems within the gut are altered during the aging process. Intestinal stem cell proliferation, epithelial barrier function, the gut microbiota, and the composition of innate and adaptive immune responses are all altered in advanced age. The aging population continues to expand worldwide, a phenomenon referred to as the "Silver Tsunami," and every effort must be made to understand how best to prevent and treat age-related maladies. Here, recent research about changes observed in the intestinal epithelium, the intestinal immune system, the microbiota, and how the aging gut interacts with and influences other organs such as the liver, lung, and brain are reviewed. Better understanding of these age-related changes and their impact on multi-organ interactions will aid the development of therapies to increase the quality of life for all aged individuals.

Shelter from the cytokine storm: pitfalls and prospects in the development of SARS-CoV-2 vaccines for an elderly population

The SARS-CoV-2 pandemic urgently calls for the development of effective preventive tools. COVID-19 hits greatly the elder and more fragile fraction of the population boosting the evergreen issue of the vaccination of older people. The development of a vaccine against SARS-CoV-2 tailored for the elderly population faces the challenge of the poor immune responsiveness of the older population due to immunosenescence, comorbidities, and pharmacological treatments. Moreover, it is likely that the inflammaging phenotype associated with age could both influence vaccination efficacy and exacerbate the risk of COVID-19-related "cytokine storm syndrome" with an overlap between the factors which impact vaccination effectiveness and those that boost virulence and worsen the prognosis of SARS-CoV-2 infection. The complex and still unclear immunopathological mechanisms of SARS-CoV-2 infection, together with the progressive age-related decline of immune responses, and the lack of clear correlates of protection, make the design of vaccination strategies for older people extremely challenging. In the ongoing effort in vaccine development, different SARS-CoV-2 vaccine candidates have been developed, tested in pre-clinical and clinical studies and are undergoing clinical testing, but only a small fraction of these are currently being tested in the older fraction of the population. Recent advances in systems biology integrating clinical, immunologic, and omics data can help to identify stable and robust markers of vaccine response and move towards a better understanding of SARS-CoV-2 vaccine responses in the elderly.

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.

Probiotics and Coronavirus disease 2019: think about the link

The pandemic of Coronavirus disease 2019 (COVID-19) is rapidly progressing, causing significant morbidity and mortality. Various antiviral drugs, anti-inflammatory drugs and immunomodulators have been tried without substantial clinical benefits. The severe and critical cases of COVID-19 disease are characterised by gut microbiome dysbiosis, immune dysregulation, hyper-inflammation and hypercytokinaemia (cytokine storm). Therefore, the strategies which target these pathophysiological processes may be beneficial. Probiotics are one such strategy that exerts beneficial effects by manipulation of the gut microbiota, suppression of opportunistic pathogens in the gut, decreasing translocation of opportunistic organisms, activation of mucosal immunity and modulation of the innate and adaptive immune response. Probiotics are the potential candidates to be tested in moderate and severe cases of COVID-19 due to several beneficial effects, including easy availability, easy to administer, safe and economical to use.

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.

Human Respiratory and Gut Microbiomes-Do They Really Contribute to Respiratory Health?

Human gastrointestinal and respiratory tracts are colonized by diverse polymicrobial communities shortly after birth, which are continuously molded by environmental exposure. The development of the resident microbiota in early life is a critical factor in the maturation of a healthy immune system. Disturbances to the intricate relationship between environmental exposure and maturation of the infant microbiome have been increasingly identified as a potential contributor to a range of childhood diseases. This review details recent evidence that implicates the contribution of gut and airway microbiome to pediatric respiratory health.