Gut microbiota, inflammation, and molecular signatures of host response to infection

Potential for curdlan recovery from aerobic granular sludge wastewater treatment systems - A review

The aerobic granular sludge (AGS) biotechnology has been explored for wastewater treatment for over two decades. AGS is gaining increased interest due to its enhanced treatment performance ability and the potential for resource recovery from AGS-based wastewater treatment systems. Resource recovery from AGS is a promising approach to sustainable wastewater treatment and attaining a circular economy in the wastewater management industry. Currently, research is at an advanced stage on recovering value-added resources such as phosphorus, polyhydroxyalkanoates, alginate-like exopolysaccharides, and tryptophan from waste aerobic granules. Recently, other value-added resources, including curdlan, have been identified in the aerobic granule matrix, and this may increase the sustainability of biotechnology in the wastewater industry. This paper provides an overview of AGS resource recovery potential. In particular, the potential for enhanced curdlan biosynthesis in the granule matrix and its recovery from AGS wastewater treatment systems is outlined.

Changes in M6A methylation: A key factor in the vicious cycle of flora -gut aging

The aging process significantly impacts the gastrointestinal tract and various bodily systems, exacerbating age-related diseases. Research suggests a correlation between an imbalance in intestinal flora and gut aging, yet the precise mechanism remains incompletely elucidated. Epigenetic modifications, particularly m6A methylation, play a pivotal role in driving aging and are closely associated with gut aging. Maintaining a healthy balance of intestinal microbes is contingent upon m6A methylation, which is believed to be crucial in the vicious cycle of gut aging and intestinal flora. This article highlights the importance of m6A methylation in the nexus between gut aging and flora. It proposes the potential for targeted m6A methylation to break the vicious cycle of gut aging and flora imbalance, offering novel perspectives on attenuating or reversing gut aging.

Cohort Profile: Guangzhou Nutrition and Health Study (GNHS): A Population-based Multi-omics Study

BACKGROUND

The Guangzhou Nutrition and Health Study (GNHS) aims to assess the determinants of metabolic disease in nutritional aspects, as well as other environmental and genetic factors, and explore possible biomarkers and mechanisms with multi-omics integration.

METHODS

The population-based sample of adults in Guangzhou, China (baseline: 40-83 years old; n = 5,118) was followed up about every 3 years. All are tracked via on-site follow-up and health information systems. We assessed detailed information on lifestyle factors, physical activities, dietary assessments, psychological health, cognitive function, body measurements, and muscle function. Instrument tests included dual-energy X-ray absorptiometry scanning, carotid artery and liver ultrasonography evaluations, vascular endothelial function evaluation, upper-abdomen and brain magnetic resonance imaging, and 14-day real-time continuous glucose monitoring tests. We also measured multi-omics, including host genome-wide genotyping, serum metabolome and proteome, gut microbiome (16S rRNA sequencing, metagenome, and internal transcribed spacer 2 sequencing), and fecal metabolome and proteome.

RESULTS

The baseline surveys were conducted from 2008 to 2015. Now, we have completed 3 waves. The 3rd and 4th follow-ups have started but have yet to end. A total of 5,118 participants aged 40-83 took part in the study. The median age at baseline was approximately 59.0 years and the proportion of female participants was about 69.4%. Among all the participants, 3,628 (71%) completed at least one on-site follow-up, with a median duration of 9.48 years.

CONCLUSION

The cohort will provide data that will be influential in establishing the role of nutrition in metabolic diseases with multi-omics.

Development and management of gastrointestinal symptoms in long-term COVID-19

Background

Emerging evidence reveals that SARS-CoV-2 possesses the capability to disrupt the gastrointestinal (GI) homeostasis, resulting in the long-term symptoms such as loss of appetite, diarrhea, gastroesophageal reflux, and nausea. In the current review, we summarized recent reports regarding the long-term effects of COVID-19 (long COVID) on the gastrointestine.

Objective

To provide a narrative review of abundant clinical evidence regarding the development and management of long-term GI symptoms in COVID-19 patients.

Results

Long-term persistent digestive symptoms are exhibited in a majority of long-COVID patients. SARS-CoV-2 infection of intestinal epithelial cells, cytokine storm, gut dysbiosis, therapeutic drugs, psychological factors and exacerbation of primary underlying diseases lead to long-term GI symptoms in COVID-19 patients. Interventions like probiotics, prebiotics, fecal microbiota transplantation, and antibiotics are proved to be beneficial in preserving intestinal microecological homeostasis and alleviating GI symptoms.

Conclusion

Timely diagnosis and treatment of GI symptoms in long-COVID patients hold great significance as they may contribute to the mitigation of severe conditions and ultimately lead to the improvement of outcomes of the patients.

Colon-Targeted Release of Gel Microspheres Loaded with Antioxidative Fullerenol for Relieving Radiation-Induced Colon Injury and Regulating Intestinal Flora

Radiation-induced colitis is a serious clinical problem worldwide. However, the current treatment options for this condition have limited efficacy and can cause side effects. To address this issue, colon-targeted fullerenol@pectin@chitosan gel microspheres (FPCGMs) are developed, which can aggregate on colon tissue for a long time, scavenge free radicals generated in the process of radiation, and regulate intestinal flora to mitigate damage to colonic tissue. First, FPCGMs exhibit acid resistance and colon-targeted release properties, which reduce gastrointestinal exposure and extend the local colonic drug residence time. Second, fullerenol, which has a superior scavenging ability and chemical stability, reduces oxidative stress in colonic epithelial cells. Based on this, it is found that FPCGMs significantly reduce inflammation in colonic tissue, mitigated damage to tight junctions of colonic epithelial cells, and significantly relieved radiation-induced colitis in mice. Moreover, 16S ribosomal DNA (16S rDNA) sequencing results show that the composition of the intestinal flora is optimized after FPCGMs are utilized, indicating that the relative abundance of probiotics increases while harmful bacteria are inhibited. These findings suggest that it is a promising candidate for treating radiation-induced colitis.

Human microbiota dysbiosis after SARS-CoV-2 infection have the potential to predict disease prognosis

BACKGROUND

The studies on SARS-CoV-2 and human microbiota have yielded inconsistent results regarding microbiota α-diversity and key microbiota. To address these issues and explore the predictive ability of human microbiota for the prognosis of SARS-CoV-2 infection, we conducted a reanalysis of existing studies.

METHODS

We reviewed the existing studies on SARS-CoV-2 and human microbiota in the Pubmed and Bioproject databases (from inception through October 29, 2021) and extracted the available raw 16S rRNA sequencing data of human microbiota. Firstly, we used meta-analysis and bioinformatics methods to reanalyze the raw data and evaluate the impact of SARS-CoV-2 on human microbial α-diversity. Secondly, machine learning (ML) was employed to assess the ability of microbiota to predict the prognosis of SARS-CoV-2 infection. Finally, we aimed to identify the key microbiota associated with SARS-CoV-2 infection.

RESULTS

A total of 20 studies related to SARS-CoV-2 and human microbiota were included, involving gut (n = 9), respiratory (n = 11), oral (n = 3), and skin (n = 1) microbiota. Meta-analysis showed that in gut studies, when limiting factors were studies ruled out the effect of antibiotics, cross-sectional and case-control studies, Chinese studies, American studies, and Illumina MiSeq sequencing studies, SARS-CoV-2 infection was associated with down-regulation of microbiota α-diversity (P < 0.05). In respiratory studies, SARS-CoV-2 infection was associated with down-regulation of α-diversity when the limiting factor was V4 sequencing region (P < 0.05). Additionally, the α-diversity of skin microbiota was down-regulated at multiple time points following SARS-CoV-2 infection (P < 0.05). However, no significant difference in oral microbiota α-diversity was observed after SARS-CoV-2 infection. ML models based on baseline respiratory (oropharynx) microbiota profiles exhibited the ability to predict outcomes (survival and death, Random Forest, AUC = 0.847, Sensitivity = 0.833, Specificity = 0.750) after SARS-CoV-2 infection. The shared differential Prevotella and Streptococcus in the gut, respiratory tract, and oral cavity was associated with the severity and recovery of SARS-CoV-2 infection.

CONCLUSIONS

SARS-CoV-2 infection was related to the down-regulation of α-diversity in the human gut and respiratory microbiota. The respiratory microbiota had the potential to predict the prognosis of individuals infected with SARS-CoV-2. Prevotella and Streptococcus might be key microbiota in SARS-CoV-2 infection.

Integrated metabolome-microbiome analysis investigates the different regulations of Pudilan Xiaoyan oral liquid in young rats with acute pharyngitis compared to adult rats

BACKGROUND

Pudilan Xiaoyan Oral Liquid (PDL) is a famous traditional Chinese prescription recorded in the Chinese Pharmacopeia, which is widely used to treat inflammatory diseases of the respiratory tract in children and adults. However, the endogenous changes in children and adults with PDL in the treatment of acute pharyngitis remain unclear.

PURPOSE

The differential regulatory roles of PDL in endogenous metabolism and gut microbes in young and adult rats were investigated with a view to providing a preclinical data reference for PDL in medication for children.

METHODS

An acute pharyngitis model was established, and serum levels of inflammatory factors and histopathology were measured. This study simulated the growth and development of children in young rats and explored the endogenous metabolic characteristics and intestinal microbial composition after the intervention of PDL by using serum metabolomic technique and 16S rRNA high-throughput sequencing technique.

RESULTS

The results showed that PDL had therapeutic effects on young and adult rats with acute pharyngitis. Sixteen biomarkers were identified by metabolomics in the serum of young rats and 23 in adult rats. PDL can also affect intestinal microbial diversity and community richness in young and adult rats. Alloprevotella, Allobaculum, Alistipes, Bifidobacterium, and Enterorhabdus were prominent bacteria in young rats. Bacteria from the phylum Firmicutes of the adult rats changed more significantly under the treatment of PDL. In young rats, amino acid metabolism was the primary regulatory mode of PDL, whereas, in adult rats, glycerophospholipid metabolism was studied.

CONCLUSION

The regulation of PDL on the serum metabolite group and intestinal microflora in young rats was different from that in adult rats, indicating the necessity of an independent study on children's medication. PDL may also exert therapeutic effects on young and adult rats by regulating gut microbial homeostasis. The results support the clinical application of PDL.

Population serum proteomics uncovers a prognostic protein classifier for metabolic syndrome

Metabolic syndrome (MetS) is a complex metabolic disorder with a global prevalence of 20%-25%. Early identification and intervention would help minimize the global burden on healthcare systems. Here, we measured over 400 proteins from ∼20,000 proteomes using data-independent acquisition mass spectrometry for 7,890 serum samples from a longitudinal cohort of 3,840 participants with two follow-up time points over 10 years. We then built a machine-learning model for predicting the risk of developing MetS within 10 years. Our model, composed of 11 proteins and the age of the individuals, achieved an area under the curve of 0.774 in the validation cohort (n = 242). Using linear mixed models, we found that apolipoproteins, immune-related proteins, and coagulation-related proteins best correlated with MetS development. This population-scale proteomics study broadens our understanding of MetS and may guide the development of prevention and targeted therapies for MetS.

The Lasting Effects of COVID-19 on the Progression of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

It is estimated that around 30% of the population living in Western countries has metabolic dysfunction-associated steatotic liver disease (MASLD), a spectrum of pathology (not attributed to alcohol/substance intake) initiated by steatosis and progression toward inflammation and irreversible fibrosis metabolic dysfunction-associated steatohepatitis (MASH). With inflammation being a key component of the transition to MASH, it raises the question of whether the ongoing COVID-19 pandemic, which has notoriously induced hyperinflammatory states, may influence the progression of MASLD. Specifically, it remains unclear if the potential chronic sequelae of COVID-19 in patients who recovered from it may increase the predisposition for MASH. Since MASH maintains a high risk for hepatocellular carcinoma, liver failure, and the need for a liver transplant, the potential additive effects of COVID-19 could prove critical to study. Thus, the objective of this study was to conduct a literature review to examine if COVID-19 could have chronic sequelae that affect the progression of MASLD pathogenesis. It was hypothesized that severe cases of COVID-19 could induce systemic inflammation, metabolic changes, and lasting gut microbiome alterations that lead to inflammatory and fibrotic changes in the liver, similar to those seen in MASH. A scoping review of the literature was conducted utilizing the PubMed database. Studies that examined hepatobiliary pathology, gut microbiome, systemic inflammation, metabolic changes, drug-induced liver injury (DILI), and hypoxia seen in COVID-19 were included. Human studies of adult cohorts, animal models, and in vitro experiments were included. Genetic components of MASLD were not examined. Exclusion criteria also encompassed any studies not referencing the hepatobiliary, gastrointestinal tract, portal system, or systemic circulation. Findings indicated a frequent trend of elevated liver enzymes, mild steatosis, Kupffer cell hyperplasia, and hepatobiliary congestion. It was found that direct cytopathic effects on hepatocytes were unlikely, but the direct viral insult of cholangiocytes was a potential complication. High serum levels of IL-1, TNF-a, and MCP-1, in COVID-19 were found as potential risk factors for MASH development. Hypoxia, altered lipid metabolism, and iatrogenic DILI were also proposed as potential precipitators of MASH development. Notably, lasting changes in gut microbiome were also frequently observed and correlated closely with those seen in MASH.

The intestinal microbiota predicts COVID-19 severity and fatality regardless of hospital feeding method

SARS-CoV-2-positive patients exhibit gut and oral microbiome dysbiosis, which is associated with various aspects of COVID-19 disease (1-4). Here, we aim to identify gut and oral microbiome markers that predict COVID-19 severity in hospitalized patients, specifically severely ill patients compared to moderately ill ones. Moreover, we investigate whether hospital feeding (solid versus enteral), an important cofounder, influences the microbial composition of hospitalized COVID-19 patients. We used random forest classification machine learning models with interpretable secondary analyses. The gut, but not the oral microbiota, was a robust predictor of both COVID-19-related fatality and severity of hospitalized patients, with a higher predictive value than most clinical variables. In addition, perturbations of the gut microbiota due to enteral feeding did not associate with species that were predictive of COVID-19 severity. IMPORTANCE SARS-CoV-2 infection leads to wide-ranging, systemic symptoms with sometimes unpredictable morbidity and mortality. It is increasingly clear that the human microbiome plays an important role in how individuals respond to viral infections. Our study adds to important literature about the associations of gut microbiota and severe COVID-19 illness during the early phase of the pandemic before the availability of vaccines. Increased understanding of the interplay between microbiota and SARS-CoV-2 may lead to innovations in diagnostics, therapies, and clinical predictions.

Disorders of gut-brain interaction in post-acute COVID-19 syndrome

The novel coronavirus SARS-CoV-2 is responsible for the devastating pandemic which has caused more than 5 million deaths across the world until today. Apart from causing acute respiratory illness and multiorgan dysfunction, there can be long-term multiorgan sequalae after recovery, which is termed 'long COVID-19' or 'post-acute COVID-19 syndrome'. Little is known about long-term gastrointestinal (GI) consequences, occurrence of post-infection functional gastrointestinal disorders and impact the virus may have on overall intestinal health. In this review, we put forth the various mechanisms which may lead to this entity and possible ways to diagnose and manage this disorder. Hence, making physicians aware of this spectrum of disease is of utmost importance in the present pandemic and this review will help clinicians understand and suspect the occurrence of functional GI disease post recovery from COVID-19 and manage it accordingly, avoiding unnecessary misconceptions and delay in treatment.

Microbial interactions and the homeostasis of the gut microbiome: the role of Bifidobacterium

The human gut is home to trillions of microorganisms that influence several aspects of our health. This dense microbial community targets almost all dietary polysaccharides and releases multiple metabolites, some of which have physiological effects on the host. A healthy equilibrium between members of the gut microbiota, its microbial diversity, and their metabolites is required for intestinal health, promoting regulatory or anti-inflammatory immune responses. In contrast, the loss of this equilibrium due to antibiotics, low fiber intake, or other conditions results in alterations in gut microbiota composition, a term known as gut dysbiosis. This dysbiosis can be characterized by a reduction in health-associated microorganisms, such as butyrate-producing bacteria, enrichment of a small number of opportunistic pathogens, or a reduction in microbial diversity. Bifidobacterium species are key species in the gut microbiome, serving as primary degraders and contributing to a balanced gut environment in various ways. Colonization resistance is a fundamental property of gut microbiota for the prevention and control of infections. This community competes strongly with foreign microorganisms, such as gastrointestinal pathogens, antibiotic-resistant bacteria, or even probiotics. Resistance to colonization is based on microbial interactions such as metabolic cross-feeding, competition for nutrients, or antimicrobial-based inhibition. These interactions are mediated by metabolites and metabolic pathways, representing the inner workings of the gut microbiota, and play a protective role through colonization resistance. This review presents a rationale for how microbial interactions provide resistance to colonization and gut dysbiosis, highlighting the protective role of Bifidobacterium species.

Gut distress and intervention via communications of SARS-CoV-2 with mucosal exposome

Acute coronavirus disease 2019 (COVID-19) has been associated with prevalent gastrointestinal distress, characterized by fecal shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA or persistent antigen presence in the gut. Using a meta-analysis, the present review addressed gastrointestinal symptoms, such as nausea, vomiting, abdominal pain, and diarrhea. Despite limited data on the gut-lung axis, viral transmission to the gut and its influence on gut mucosa and microbial community were found to be associated by means of various biochemical mechanisms. Notably, the prolonged presence of viral antigens and disrupted mucosal immunity may increase gut microbial and inflammatory risks, leading to acute pathological outcomes or post-acute COVID-19 symptoms. Patients with COVID-19 exhibit lower bacterial diversity and a higher relative abundance of opportunistic pathogens in their gut microbiota than healthy controls. Considering the dysbiotic changes during infection, remodeling or supplementation with beneficial microbial communities may counteract adverse outcomes in the gut and other organs in patients with COVID-19. Moreover, nutritional status, such as vitamin D deficiency, has been associated with disease severity in patients with COVID-19 via the regulation of the gut microbial community and host immunity. The nutritional and microbiological interventions improve the gut exposome including the host immunity, gut microbiota, and nutritional status, contributing to defense against acute or post-acute COVID-19 in the gut-lung axis.

Gut Microbiome in Post-COVID-19 Patients Is Linked to Immune and Cardiovascular Health Status but Not COVID-19 Severity

The composition of the gut microbiome stores the imprints of prior infections and other impacts. COVID-19 can cause changes in inflammatory status that persist for a considerable time after infection ends. As the gut microbiome is closely associated with immunity and inflammation, the infection severity might be linked to its community structure dynamics. Using 16S rRNA sequencing of stool samples, we investigated the microbiome three months after the end of the disease/infection or SARS-CoV-2 contact in 178 post-COVID-19 patients and those who contacted SARS-CoV-2 but were not infected. The cohort included 3 groups: asymptomatic subjects (n = 48), subjects who contacted COVID-19 patients with no further infection (n = 46), and severe patients (n = 86). Using a novel compositional statistical algorithm (nearest balance) and the concept of bacterial co-occurrence clusters (coops), we compared microbiome compositions between the groups as well as with multiple categories of clinical parameters including: immunity, cardiovascular parameters and markers of endothelial dysfunction, and blood metabolites. Although a number of clinical indicators varied drastically across the three groups, no differences in microbiome features were identified between them at this follow-up point. However, there were multiple associations between the microbiome features and clinical data. Among the immunity parameters, the relative lymphocyte number was linked to a balance including 14 genera. Cardiovascular parameters were associated with up to four bacterial cooperatives. Intercellular adhesion molecule 1 was linked to a balance including ten genera and one cooperative. Among the blood biochemistry parameters, calcium was the only parameter associated with the microbiome via a balance of 16 genera. Our results suggest comparable recovery of the gut community structure in the post-COVID-19 period, independently of severity or infection status. The multiple identified associations of clinical analysis data with the microbiome provide hypotheses about the participation of specific taxa in regulating immunity and homeostasis of cardiovascular and other body systems in health, as well as their disruption in SARS-CoV-2 infections and other diseases.

COVID-19 Spotlights Connections between Disease and Multiple Lifestyle Factors

The SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2), and the disease it causes (COVID-19), have had a profound impact on global human society and threaten to continue to have such an impact with newly emerging variants. Because of the widespread effects of SARS-CoV-2, understanding how lifestyle choices impact the severity of disease is imperative. This review summarizes evidence for an involvement of chronic, non-resolving inflammation, gut microbiome disruption (dysbiosis with loss of beneficial microorganisms), and impaired viral defenses, all of which are associated with an imbalanced lifestyle, in severe disease manifestations and post-acute sequelae of SARS-CoV-2 (PASC). Humans' physiological propensity for uncontrolled inflammation and severe COVID-19 are briefly contrasted with bats' low propensity for inflammation and their resistance to viral disease. This insight is used to identify positive lifestyle factors with the potential to act in synergy for restoring balance to the immune response and gut microbiome, and thereby protect individuals against severe COVID-19 and PASC. It is proposed that clinicians should consider recommending lifestyle factors, such as stress management, balanced nutrition and physical activity, as preventative measures against severe viral disease and PASC.

Genome-wide genotype-serum proteome mapping provides insights into the cross-ancestry differences in cardiometabolic disease susceptibility

Identification of protein quantitative trait loci (pQTL) helps understand the underlying mechanisms of diseases and discover promising targets for pharmacological intervention. For most important class of drug targets, genetic evidence needs to be generalizable to diverse populations. Given that the majority of the previous studies were conducted in European ancestry populations, little is known about the protein-associated genetic variants in East Asians. Based on data-independent acquisition mass spectrometry technique, we conduct genome-wide association analyses for 304 unique proteins in 2,958 Han Chinese participants. We identify 195 genetic variant-protein associations. Colocalization and Mendelian randomization analyses highlight 60 gene-protein-phenotype associations, 45 of which (75%) have not been prioritized in Europeans previously. Further cross-ancestry analyses uncover key proteins that contributed to the differences in the obesity-induced diabetes and coronary artery disease susceptibility. These findings provide novel druggable proteins as well as a unique resource for the trans-ancestry evaluation of protein-targeted drug discovery.

Swimming exercise ameliorates depressive-like behavior by anti-inflammation activity, rebalancing gut Escherichia coli and Lactobacilli

Major depressive disorder (MDD) is a common mental disease with high morbidity, recurrence and mortality and is a serious global health problem.Aerobic exercise produces beneficial effects on depression and associated comorbidities.Swimming exercise with high motor complexity may be particularly beneficial for patients with depression.We hypothesized that swimming exercise improves various types of depression-like behaviors and these effects are related to improved immune and inflammatory response by regulating microbiota-gut-brain axis.We established the Lipopolysaccharides (LPS)/Chronic unpredictable stress (CUS) mice model of depression. The forced swimming test (FST) and tail suspension test (TST) were used as predictive animal models of antidepressant-like activity.Swimming exercise significantly decreased the duration of immobility in FST and TST.We found that swimming exercise could significantly decrease the levels of pro-inflammatory cytokines in the central nervous system (CNS). Shifts in the composition of the gut microbiota were significant in depression model induced by LPS/CUS, notably as decreases in lactobacilli and increases in escherichia coli (E. coli), which were reversed byswimming exercise. Current study indicated that swimming exercise has huge potential for antidepressant therapy, and gut microbiotaplays an important role inregulating inflammation. We are pleased that current can study reveal a potentially promising method with less adverse reaction for combating depression and open up an important new area for future research.

The impact of aging on intestinal mucosal immune function and clinical applications

Immune cells and immune molecules in the intestinal mucosa participate in innate and adaptive immunity to maintain local and systematic homeostasis. With aging, intestinal mucosal immune dysfunction will promote the emergence of age-associated diseases. Although there have been a number of studies on the impact of aging on systemic immunity, relatively fewer studies have been conducted on the impact of aging on the intestinal mucosal immune system. In this review, we will briefly introduce the impact of aging on the intestinal mucosal barrier, the impact of aging on intestinal immune cells as well as immune molecules, and the process of interaction between intestinal mucosal immunity and gut microbiota during aging. After that we will discuss potential strategies to slow down intestinal aging in the elderly.

Association of SARS-CoV-2 and Polypharmacy with Gut-Lung Axis: From Pathogenesis to Treatment

SARS-CoV-2 is a novel infectious contagion leading to COVID-19 disease. The virus has affected the lives of millions of people across the globe with a high mortality rate. It predominantly affects the lung (respiratory system), but it also affects other organs, including the cardiovascular, psychological, and gastrointestinal (GIT) systems. Moreover, elderly and comorbid patients with compromised organ functioning and pre-existing polypharmacy have worsened COVID-19-associated complications. Microbiota (MB) of the lung plays an important role in developing COVID-19. The extent of damage mainly depends on the predominance of opportunistic pathogens and, inversely, with the predominance of advantageous commensals. Changes in the gut MB are associated with a bidirectional shift in the interaction among the gut with a number of vital human organs, which leads to severe disease symptoms. This review focuses on dysbiosis in the gut-lung axis, COVID-19-induced worsening of comorbidities, and the influence of polypharmacy on MB.

Factors Modulating COVID-19: A Mechanistic Understanding Based on the Adverse Outcome Pathway Framework

Addressing factors modulating COVID-19 is crucial since abundant clinical evidence shows that outcomes are markedly heterogeneous between patients. This requires identifying the factors and understanding how they mechanistically influence COVID-19. Here, we describe how eleven selected factors (age, sex, genetic factors, lipid disorders, heart failure, gut dysbiosis, diet, vitamin D deficiency, air pollution and exposure to chemicals) influence COVID-19 by applying the Adverse Outcome Pathway (AOP), which is well-established in regulatory toxicology. This framework aims to model the sequence of events leading to an adverse health outcome. Several linear AOPs depicting pathways from the binding of the virus to ACE2 up to clinical outcomes observed in COVID-19 have been developed and integrated into a network offering a unique overview of the mechanisms underlying the disease. As SARS-CoV-2 infectibility and ACE2 activity are the major starting points and inflammatory response is central in the development of COVID-19, we evaluated how those eleven intrinsic and extrinsic factors modulate those processes impacting clinical outcomes. Applying this AOP-aligned approach enables the identification of current knowledge gaps orientating for further research and allows to propose biomarkers to identify of high-risk patients. This approach also facilitates expertise synergy from different disciplines to address public health issues.

Uncovering the genetic links of SARS-CoV-2 infections on heart failure co-morbidity by a systems biology approach

Aims

The co‐morbidities contribute to the inferior prognosis of COVID‐19 patients. Recent reports suggested that the higher co‐morbidity rate between COVID‐19 and heart failure (HF) leads to increased mortality. However, the common pathogenic mechanism between them remained elusive. Here, we aimed to reveal underlying molecule mechanisms and genetic correlation between COVID‐19 and HF, providing a new perspective on current clinical management for patients with co‐morbidity.

Methods

The gene expression profiles of HF (GSE26887) and COVID‐19 (GSE147507) were retrieved from the GEO database. After identifying the common differentially expressed genes (|log2FC| > 1 and adjusted P < 0.05), integrated analyses were performed, namely, enrichment analyses, protein–protein interaction network, module construction, critical gene identification, and functional co‐expression analysis. The performance of critical genes was validation combining hierarchical clustering, correlation, and principal component analysis in external datasets (GSE164805 and GSE9128). Potential transcription factors and miRNAs were obtained from the JASPER and RegNetwork repository used to construct co‐regulatory networks. The candidate drug compounds in potential genetic link targets were further identified using the DSigDB database.

Results

The alteration of 12 genes was identified as a shared transcriptional signature, with the role of immune inflammatory pathway, especially Toll‐like receptor, NF‐kappa B, chemokine, and interleukin‐related pathways that primarily emphasized in response to SARS‐CoV‐2 complicated with HF. Top 10 critical genes (TLR4, TLR2, CXCL8, IL10, STAT3, IL1B, TLR1, TP53, CCL20, and CXCL10) were identified from protein–protein interaction with topological algorithms. The unhealthy microbiota status and gut–heart axis in co‐morbidity were identified as potential disease roads in bridging pathogenic mechanism, and lipopolysaccharide acts as a potential marker for monitoring HF during COVID‐19. For transcriptional and post‐transcriptional levels, regulation networks tightly coupling with both disorders were constructed, and significant regulator signatures with high interaction degree, especially FOXC1, STAT3, NF‐κB1, miR‐181, and miR‐520, were detected to regulate common differentially expressed genes. According to genetic links targets, glutathione‐based antioxidant strategy combined with muramyl dipeptide‐based microbe‐derived immunostimulatory therapies was identified as promising anti‐COVID‐19 and anti‐HF therapeutics.

Conclusions

This study identified shared transcriptomic and corresponding regulatory signatures as emerging therapeutic targets and detected a set of pharmacologic agents targeting genetic links. Our findings provided new insights for underlying pathogenic mechanisms between COVID‐19 and HF.

Disease-associated dysbiosis and potential therapeutic role of Akkermansia muciniphila, a mucus degrading bacteria of gut microbiome

The unique functionality of Akkermansia muciniphila in gut microbiota indicates it to be an indispensable microbe for human welfare. The importance of A. muciniphila lies in its potential to convert mucin into beneficial by-products, regulate intestinal homeostasis and maintain gut barrier integrity. It is also known to competitively inhibit other mucin-degrading bacteria and improve metabolic functions and immunity responses in the host. It finds a pivotal perspective in various diseases and their treatment. It has future as a promising probiotic, disease biomarker and therapeutic agent for chronic diseases. Disease-associated dysbiosis of A. muciniphila in the gut microbiome makes it a potential candidate as a biomarker for some diseases and can provide future theranostics by suggesting ways of diagnosis for the patients and best treatment method based on the screening results. Manipulation of A. muciniphila in gut microbiome may help in developing a novel personalized therapeutic action and can be a suitable next generation medicine. However, the actual pathway governing A. muciniphila interaction with hosts remains to be investigated. Also, due to the limited availability of products containing A. muciniphila, it is not exploited to its full potential. The present review aims at highlighting the potential of A. muciniphila in mucin degradation, contribution towards the gut health and host immunity and management of metabolic diseases such as obesity and type 2 diabetes, and respiratory diseases such as cystic fibrosis and COVID-19.

Any Future for Faecal Microbiota Transplantation as a Novel Strategy for Gut Microbiota Modulation in Human and Veterinary Medicine?

Alterations in the composition of the intestinal microbiome, also known as dysbiosis, are the result of many factors such as diet, antibiotics, stress, diseases, etc. There are currently several ways to modulate intestinal microbiome such as dietary modulation, the use of antimicrobials, prebiotics, probiotics, postbiotics, and synbiotics. Faecal microbiota transplantation (FMT) represents one new method of gut microbiota modulation in humans with the aim of reconstructing the intestinal microbiome of the recipient. In human medicine, this form of bacteriotherapy is successfully used in cases of recurrent Clostridium difficile infection (CDI). FMT has been known in large animal medicine for several years. In small animal medicine, the use of FMT is not part of normal practice.

Distal Consequences of Mucosal Infections in Intestinal and Lung Inflammation

Infectious diseases are one of the leading causes of morbidity and mortality worldwide, affecting high-risk populations such as children and the elderly. Pathogens usually activate local immune responses at the site of infection, resulting in both protective and inflammatory responses, which may lead to local changes in the microbiota, metabolites, and the cytokine environment. Although some pathogens can disseminate and cause systemic disease, increasing evidence suggests that local infections can affect tissues not directly invaded. In particular, diseases occurring at distal mucosal barriers such as the lung and the intestine seem to be linked, as shown by epidemiological studies in humans. These mucosal barriers have bidirectional interactions based mainly on multiple signals derived from the microbiota, which has been termed as the gut-lung axis. However, the effects observed in such distal places are still incompletely understood. Most of the current research focuses on the systemic impact of changes in microbiota and bacterial metabolites during infection, which could further modulate immune responses at distal tissue sites. Here, we describe how the gut microbiota and associated metabolites play key roles in maintaining local homeostasis and preventing enteric infection by direct and indirect mechanisms. Subsequently, we discuss recent murine and human studies linking infectious diseases with changes occurring at distal mucosal barriers, with particular emphasis on bacterial and viral infections affecting the lung and the gastrointestinal tract. Further, we discuss the potential mechanisms by which pathogens may cause such effects, promoting either protection or susceptibility to secondary infection.

The Concept of Intrauterine Programming and the Development of the Neonatal Microbiome in the Prevention of SARS-CoV-2 Infection

The process of intrauterine programming is related to the quality of the microbiome formed in the fetus and the newborn. The implementation of probiotics, prebiotics, and psychobiotics shows immunomodulatory potential towards the organism, especially the microbiome of the pregnant woman and her child. Nutrigenomics, based on the observation of pregnant women and the developing fetus, makes it possible to estimate the biological effects of active dietary components on gene expression or silencing. Nutritional intervention for pregnant women should consider the nutritional status of the patient, biological markers, and the potential impact of dietary intervention on fetal physiology. The use of a holistic model of nutrition allows for appropriately targeted and effective dietary prophylaxis that can impact the physical and mental health of both the mother and the newborn. This model targets the regulation of the immune response of the pregnant woman and the newborn, considering the clinical state of the microbiota and the pathomechanism of the nervous system. Current scientific reports indicate the protective properties of immunobiotics (probiotics) about the reduction of the frequency of infections and the severity of the course of COVID-19 disease. The aim of this study was to test the hypothesis that intrauterine programming influences the development of the microbiome for the prevention of SARS-CoV-2 infection based on a review of research studies.

Potential Application of Tea Polyphenols to the Prevention of COVID-19 Infection: Based on the Gut-Lung Axis

Coronavirus disease 2019 (COVID-19) disrupts the intestinal micro-ecological balance, and patients often develop the intestinal disease. The gut is the largest immune organ in the human body; intestinal microbes can affect the immune function of the lungs through the gut-lung axis. It has been reported that tea polyphenols (TPs) have antiviral and prebiotic activity. In this review, we discussed TPs reduced lung-related diseases through gut-lung axis by inhibiting dysbiosis. In addition, we also highlighted the preventive and therapeutic effects of TPs on COVID-19 complications, further demonstrating the importance of research on TPs for the prevention and treatment of COVID-19 in humans. Based on this understanding, we recommend using TPs to regulate the gut microbiota to prevent or alleviate COVID-19 through the gut-lung axis.

Cerebral Intraparenchymal Hemorrhage Changes Patients’ Gut Bacteria Composition and Function

Gut bacteria consists of 150 times more genes than humans that are vital for health. Several studies revealed that gut bacteria are associated with disease status and influence human behavior and mentality. Whether human brain injury alters the gut bacteria is yet unclear, we tested 20 fecal samples from patients with cerebral intraparenchymal hemorrhage and corresponding healthy controls through metagenomic shotgun sequencing. The composition of patients’ gut bacteria changed significantly at the phylum level; Verrucomicrobiota was the specific phylum colonized in the patients’ gut. The functional alteration was observed in the patients’ gut bacteria, including high metabolic activity for nutrients or neuroactive compounds, strong antibiotic resistance, and less virulence factor diversity. The changes in the transcription and metabolism of differential species were more evident than those of the non-differential species between groups, which is the primary factor contributing to the functional alteration of patients with cerebral intraparenchymal hemorrhage.

The Association between the Oral-Gut Axis and the Outcomes of Severe COVID-19 Patients Receiving Extracorporeal Membrane Oxygenation: A Case-Control Study

The novel conceptual disease model, the oral–gut axis, which represents the immunomodulatory mutual relationship between oral and gut microbial compartments, has been attracting attention in relation to systemic health issues. We investigated whether this unique crosstalk influences the systemic condition of patients with COVID-19 infections who received extracorporeal membrane oxygenation (ECMO) in the intensive care unit (ICU) during April and December 2020. In this case-control study, patients were divided into two groups according to their survival (total entry size, n = 21; survivors, n = 13; non-survivors, n = 8). Patients were evaluated using the oral assessment guide from Fukuoka University (OAG-F) and the Bristol Stool Form Scale (BSFS) to examine the oral and fecal conditions. A blood-based inflammatory factor, the neutrophil-to-lymphocyte ratio (NLR), was used as an indicator of systemic immunity. The high total OAG-F scores were associated with both elevated BSFS and NLR values, and a mutually positive correlation between BSFS and NLR was observed. This indicated an interplay between oral deterioration, gut dysbiosis, and the impairment of immunity. Furthermore, oral deterioration was more frequently observed in non-survivors on day 14 of ICU admission. In addition, on days 7 and 21 of ICU admission, impaired immunity, reflected by an elevated NLR, was observed in non-survivors. However, the distribution of the gut microbiome—reflected by increased BSFS values—with the time it was examined was not directly observed in non-survivors. Taken together, these findings suggested that oral–gut health may be specifically associated with mortality in COVID-19 patients receiving ECMO in the ICU.

Modulation of Intestinal Barrier, Inflammatory Response, and Gut Microbiota by Pediococcus pentosaceus zy-B Alleviates Vibrio parahaemolyticus Infection in C57BL/6J Mice

Modulation of the intestinal barrier, inflammation, and gut microbiota by Pediococcus pentosaceus zy-B (zy-B) in Vibrio parahaemolyticus (Vp)-infected C57BL/6J mice was studied. Mice intragastrically pretreated with 10⁸ colony-forming units (CFU) zy-B significantly alleviated Vp infection as evidenced by maintaining body weight and reduced disease activity index score and intestine ratio. In addition, zy-B reduced the Vp load in the ileum and cecum, significantly reduced the load in the colon, prevented colonic atrophy, and strengthened mucosal integrity. Mechanistically, zy-B ameliorated intestinal barrier dysfunction by upregulating tight junction protein expression, which in turn reduced the lipopolysaccharide, d-lactic acid (d-LA), and diamine oxidase concentrations and downregulated the cannabinoid receptor 1 (CB1) and CB2 mRNA expressions. Moreover, zy-B systemically reduced inflammation by decreasing interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α levels, and increased interleukin-10 (IL-10), immunoglobulin M (IgM), and immunoglobulin G (IgG) levels in the colon and serum. Furthermore, zy-B markedly altered the gut microbiota composition by enriching Bifidobacterium, Akkermansia, and Lactobacillus in the colon. Overall, zy-B appears to act as a probiotic to alleviate Vp infection by protecting the intestinal barrier, reducing inflammation, and promoting the growth of "beneficial" gut microbiota.

Evidences and perspectives of the use of probiotics, prebiotics, synbiotics, and postbiotics as adjuvants for prevention and treatment of COVID-19: A bibliometric analysis and systematic review

BACKGROUND

Coronavirus disease-19 (COVID-19) is an infectious disease transmitted by the virus responsible for the severe acute respiratory syndrome 2 (SARS-CoV-2), which exhibit several clinical manifestations including gastrointestinal symptoms.

SCOPE AND APPROACH

This review aimed to provide insights and perspectives for the use of probiotics, prebiotics, synbiotics, and postbiotics as adjuvants for prevention/treatment and/or modulation of the microbiota in COVID-19 patients. Eighty-four studies published in the Scopus database from the onset of the pandemic until December 2021 were assessed and submitted to a bibliometric analysis adapted from VOSviewer software.

KEY FINDINGS AND CONCLUSIONS

Through bibliometric analysis, it might be suggested that the modulation of the gut/lung microbiome is promising as an adjuvant for the prevention/treatment of COVID-19 patients, due to immunomodulation properties related to probiotics and prebiotics. So far, few clinical studies involving the application of probiotics in COVID-19 patients have been completed, but reduction in the duration of the disease and the severity of symptoms as fatigue, olfactory dysfunction and breathlessness, nausea and vomiting and other gastrointestinal symptoms were some of the main findings. However, probiotics are not recommended to immunocompromised patients in corticosteroid therapy. The future perspectives point to the modulation of the intestinal microbiota by probiotics, prebiotics, synbiotics, and postbiotics represent a promising adjuvant approach for improving the health of patients with COVID-19.

The "Microbiome": A Protagonist in COVID-19 Era

Respiratory infections are among the main causes of hospitalization and mortality, particularly in elderly patients [...].

The role of the microbiota in the management of intensive care patients

The composition of the gut microbiota is highly dynamic and changes according to various conditions. The gut microbiota mainly includes difficult-to-cultivate anaerobic bacteria, hence knowledge about its composition has significantly arisen from culture-independent methods based on next-generation sequencing (NGS) such as 16S profiling and shotgun metagenomics. The gut microbiota of patients hospitalized in intensive care units (ICU) undergoes many alterations because of critical illness, antibiotics, and other ICU-specific medications. It is then characterized by lower richness and diversity, and dominated by opportunistic pathogens such as Clostridioides difficile and multidrug-resistant bacteria. These alterations are associated with an increased risk of infectious complications or death. Specifically, at the time of writing, it appears possible to identify distinct microbiota patterns associated with severity or infectivity in COVID-19 patients, paving the way for the potential use of dysbiosis markers to predict patient outcomes. Correcting the microbiota disturbances to avoid their consequences is now possible. Fecal microbiota transplantation is recommended in recurrent C. difficile infections and microbiota-protecting treatments such as antibiotic inactivators are currently being developed. The growing interest in the microbiota and microbiota-associated therapies suggests that the control of the dysbiosis could be a key factor in the management of critically ill patients. The present narrative review aims to provide a synthetic overview of microbiota, from healthy individuals to critically ill patients. After an introduction to the different techniques used for studying the microbiota, we review the determinants involved in the alteration of the microbiota in ICU patients and the latter's consequences. Last, we assess the means to prevent or correct microbiota alteration.

Gut microbiome, Vitamin D, ACE2 interactions are critical factors in immune-senescence and inflammaging: key for vaccine response and severity of COVID-19 infection

BACKGROUND

The SARS-CoV-2 pandemic continues to spread sporadically in the Unites States and worldwide. The severity and mortality excessively affected the frail elderly with co-existing medical diseases. There is growing evidence that cross-talk between the gut microbiome, Vitamin D and RAS/ACE2 system is essential for a balanced functioning of the elderly immune system and in regulating inflammation. In this review, we hypothesize that the state of gut microbiome, prior to infection determines the outcome associated with COVID-19 sepsis and may also be a critical factor in success to vaccination.

METHODS

Articles from PubMed/Medline searches were reviewed using a combination of terms "SARS-CoV-2, COVID-19, Inflammaging, Immune-senescence, Gut microbiome, Vitamin D, RAS/ACE2, Vaccination".

CONCLUSION

Evidence indicates a complex association between gut microbiota, ACE-2 expression and Vitamin D in COVID-19 severity. Status of gut microbiome is highly predictive of the blood molecular signatures and inflammatory markers and host responses to infection. Vitamin D has immunomodulatory function in innate and adaptive immune responses to viral infection. Anti-inflammatory functions of Vit D include regulation of gut microbiome and maintaining microbial diversity. It promotes growth of gut-friendly commensal strains of Bifida and Fermicutus species. In addition, Vitamin D is a negative regulator for expression of renin and interacts with the RAS/ ACE/ACE-2 signaling axis. Collectively, this triad may be the critical, link in determination of outcomes in SARS-CoV-2 infection. The presented data are empirical and informative. Further research using advanced systems biology techniques and artificial intelligence-assisted integration could assist with correlation of the gut microbiome with sepsis and vaccine responses. Modulating these factors may impact in guiding the success of vaccines and clinical outcomes in COVID-19 infections.

Lactobacillus plantarum induces innate cytokine responses that potentially provide a protective benefit against COVID-19: A single-arm, double-blind, prospective trial combined with an in vitro cytokine response assay

Intestinal microbiota can indirectly modulate airway physiology and immunity through the gut-lung axis. Recent microbiome studies indicate that patients with coronavirus disease 2019 (COVID-19) exhibit a specific intestinal dysbiosis that is closely associated with the disease pathophysiology. Therefore, rebalancing the intestinal microbiome using probiotics may be effective for controlling COVID-19. However, the rationale for using probiotics in COVID-19 remains unclear. In the present study, an in vitro cytokine response assay was conducted, followed by a single-arm, double-blind, prospective trial to evaluate the immunological efficacy of probiotic lactic acid bacteria against COVID-19. The present study focused on Lactobacillus plantarum (L. plantarum), Bifidobacterium longum and Lactococcus lactis ssp. lactis, which exhibit robust protective effects against infection with respiratory RNA viruses. Considering the feasibility of long-term daily intake for prophylactic purposes, healthy uninfected individuals were enrolled as subjects. Our previous pilot trial demonstrated that oral Qingfei Paidu decoction (QFPD), a Chinese herbal medicine formulated specifically against COVID-19, upregulates plasma TNF-α, IL-1β, IL-18 and IL-8. Therefore, the present study utilized the cytokine changes induced by QFPD to define the innate cytokine index QICI [=(TNF-α) x (IL-1β) x (IL-18) x (IL-8)/(IL-6)] as an indicator of the anti-COVID-19 immunomodulatory potential of the lactic acid bacteria. A total of 20 eligible volunteers were enrolled, 18 of whom completed the intervention. L. plantarum demonstrated a strikingly high innate cytokine index in all subjects in the in vitro cytokine response assay. In the subsequent trial, oral intake of L. plantarum significantly increased the innate cytokine index (mean fold change, 17-fold; P=0.0138) and decreased the plasma level of IL-6 (P=0.0128), a key driver of complex immune dysregulation in COVID-19, as compared with the baseline. The cytokine index increased in 16 of 18 subjects (88.9%) with considerable individual differences in the fold change (1- to 128-fold). In line with these innate cytokine changes, L. plantarum ingestion significantly enhanced the activity of natural killer cells. By contrast, oral B. longum failed to induce a significant increase in the innate cytokine index (mean fold change, 2-fold; P=0.474) as compared with the baseline. In conclusion, L. plantarum demonstrated superior QFPD-like immunomodulatory ability and mimicked the blood cytokine environment produced by early immune responses to viral infection. Daily consumption of L. plantarum as an anti-COVID-19 probiotic may be a possible option for preventing COVID-19 during the pandemic. The present study was prospectively registered in the University Hospital Medical Information Network-Clinical Trials Registry under the trial number UMIN000040479 on 22 May 2020 (https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046202).

Nasopharyngeal Microbiota as an early severity biomarker in COVID-19 hospitalised patients: a retrospective cohort study in a Mediterranean area

This study aimed to analyse the diversity and taxonomic composition of the nasopharyngeal microbiota, to determine its association with COVID-19 clinical outcome. To study the microbiota, we utilized 16S rRNA sequencing of 177 samples that came from a retrospective cohort of COVID-19 hospitalized patients. Raw sequences were processed by QIIME2. The associations between microbiota, invasive mechanical ventilation (IMV), and all-cause mortality were analysed by multiple logistic regression, adjusted for age, gender, and comorbidity. The microbiota α diversity indexes were lower in patients with a fatal outcome, whereas the β diversity analysis showed a significant clustering in these patients. After multivariate adjustment, the presence of Selenomonas spp., Filifactor spp., Actinobacillus spp., or Chroococcidiopsis spp., was associated with a reduction of more than 90% of IMV. Higher diversity and the presence of certain genera in the nasopharyngeal microbiota seem to be early biomarkers of a favourable clinical evolution in hospitalized COVID-19 patients.

Punicalagin Regulates Signaling Pathways in Inflammation-Associated Chronic Diseases

Inflammation is a complex biological defense system associated with a series of chronic diseases such as cancer, arthritis, diabetes, cardiovascular and neurodegenerative diseases. The extracts of pomegranate fruit and peel have been reported to possess health-beneficial properties in inflammation-associated chronic diseases. Punicalagin is considered to be the major active component of pomegranate extracts. In this review we have focused on recent studies into the therapeutic effects of punicalagin on inflammation-associated chronic diseases and the regulatory roles in NF-κB, MAPK, IL-6/JAK/STAT3 and PI3K/Akt/mTOR signaling pathways. We have concluded that punicalagin may be a promising therapeutic compound in preventing and treating inflammation-associated chronic diseases, although further clinical studies are required.

Human Gut Microbiome as an Indicator of Human Health

The undeniable achievement in the study of the gut microbiome as an association of different microorganisms, including viruses, that colonize various organs and systems of the body, is the establishment of the fact that some diseases that were consmicrobiotaidered as non-infectious can also be transmitted through microorganisms. This resulted in the gut microbiome being called a forgotten organ that could serve as an additional and kind of missing link for a more objective and better diagnosis and treatment of many diseases that were not considered infectious. The rapid development of gut microbiome research in recent years not only is connected with better understanding of the functioning of the microbiome by the scientific community, but also inseparable from the strategic support of each country. Global investment in researches, related to the human microbiome, has exceeded $1.7 billion over the past decade. These researches contribute to the development of new diagnostic methods and therapeutic interventions. Our review is dedicated to the analysis of the possibilities of application of the human gut microbiome for the diagnosis of diseases, and the role of the intestines in the provocation and causing of certain diseases. Significant differences in the composition and diversity of the human microbiome are shown depending on geographical location and the change of socio-economic formations towards a gradual decrease in the diversity of the gut microbiome due to three stages of human population’s existence: food production, agriculture and industrial urban life. We analyze the influence of dietary patterns, various diseases (including malignant neoplasms) and viral infections (in particular, coronavirus) on the gut microbiome. And vice versa – the influence of the gut microbiome on the drugs effect and their metabolism, which affects the host's immune response and course of the disease.

The gut microbiome as a biomarker of differential susceptibility to SARS-CoV-2

Coronavirus disease 2019 (COVID-19) continues to exact a devastating global toll. Ascertaining the factors underlying differential susceptibility and prognosis following viral exposure is critical to improving public health responses. We propose that gut microbes may contribute to variation in COVID-19 outcomes. We synthesise evidence for gut microbial contributions to immunity and inflammation, and associations with demographic factors affecting disease severity. We suggest mechanisms potentially underlying microbially mediated differential susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). These include gut microbiome-mediated priming of host inflammatory responses and regulation of endocrine signalling, with consequences for the cellular features exploited by SARS-CoV-2 virions. We argue that considering gut microbiome-mediated mechanisms may offer a lens for appreciating differential susceptibility to SARS-CoV-2, potentially contributing to clinical and epidemiological approaches to understanding and managing COVID-19.

Human bronchial-pulmonary proteomics in coronavirus disease 2019 (COVID-19) pandemic: applications and implications

INTRODUCTION

The outbreak of the newly discovered human coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has disrupted the normal life of almost every civilization worldwide. Studies have shown that the coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 can affect multiple human organs and physiological systems, but the respiratory system remains the primary location for viral infection.

AREAS COVERED

We summarize how omics technologies are used in SARS-CoV-2 research and specifically review the current knowledge of COVID-19 from the aspect of human bronchial-pulmonary proteomics. Also, knowledge gaps in COVID-19 that can be fulfilled by proteomics are discussed.

EXPERT OPINION

Overall, human bronchial-pulmonary proteomics plays an important role in revealing the dynamics, functions, tropism, and pathogenicity of SARS-CoV-2, which is crucial for COVID-19 biomarker and therapeutic target discoveries. To more fully understand the impact of COVID-19, research from various angles using multi-omics approaches should also be conducted on the lungs as well as other organs.

High association of COVID-19 severity with poor gut health score in Lebanese patients

Background

Coronavirus disease 2019 (COVID-19) has affected millions of lives globally. However, the disease has presented more extreme challenges for developing countries that are experiencing economic crises. Studies on COVID-19 symptoms and gut health are scarce and have not fully analyzed possible associations between gut health and disease pathophysiology. Therefore, this study aimed to demonstrate a potential association between gut health and COVID-19 severity in the Lebanese community, which has been experiencing a severe economic crisis.

Methods

This cross-sectional study investigated SARS-CoV-2 PCR-positive Lebanese patients. Participants were interviewed and gut health, COVID-19 symptoms, and different metrics were analyzed using simple and multiple logistic regression models.

Results

Analysis of the data showed that 25% of participants were asymptomatic, while an equal proportion experienced severe symptoms, including dyspnea (22.7%), oxygen need (7.5%), and hospitalization (3.1%). The mean age of the participants was 38.3 ±0.8 years, and the majority were males (63.9%), married (68.2%), and currently employed (66.7%). A negative correlation was found between gut health score and COVID-19 symptoms (Kendall’s tau-b = -0.153, P = 0.004); indicating that low gut health was associated with more severe COVID-19 cases. Additionally, participants who reported unhealthy food intake were more likely to experience severe symptoms (Kendall’s tau-b = 0.118, P = 0.049). When all items were taken into consideration, multiple ordinal logistic regression models showed a significant association between COVID-19 symptoms and each of the following variables: working status, flu-like illness episodes, and gut health score. COVID-19 severe symptoms were more common among patients having poor gut health scores (OR:1.31, 95%CI:1.07–1.61; P = 0.008), experiencing more than one episode of flu-like illness per year (OR:2.85, 95%CI:1.58–5.15; P = 0.001), and owning a job (OR:2.00, 95%CI:1.1–3.65; P = 0.023).

Conclusions

To our knowledge, this is the first study that showed the impact of gut health and exposure to respiratory viruses on COVID-19 severity in Lebanon. These findings can facilitate combating the pandemic in Lebanon.

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.

Point-of-care detection of cytokines in cytokine storm management and beyond: Significance and challenges

Cytokines are signaling molecules between cells in immune system. Cytokine storm, due to the sudden acute increase in levels of pro-inflammatory circulating cytokines, can result in disease severity and major-organ damage. Thus, there is urgent need to develop rapid, sensitive, and specific methods for monitoring of cytokines in biology and medicine. Undoubtedly, point-of-care testing (POCT) will provide clinical significance in disease early diagnosis, management, and prevention. This review aims to summarize and discuss the latest technologies for detection of cytokines with a focus on POCT. The overview of diseases resulting from imbalanced cytokine levels, such as COVID-19, sepsis and other cytokine release syndromes are presented. The clinical cut-off levels of cytokine as biomarkers for different diseases are summarized. The challenges and perspectives on the development of cytokine POCT devices are also proposed and discussed. Cytokine POCT devices are expected to be the ongoing spotlight of disease management and prevention during COVID-19 pandemic and also the post COVID-19 pandemic era.