Gut Dysbiosis during COVID-19 and Potential Effect of Probiotics

Neurodevelopmental implications of COVID-19-induced gut microbiome dysbiosis in pregnant women

The global public health emergency of COVID-19 in January 2020 prompted a surge in research focusing on the pathogenesis and clinical manifestations of the virus. While numerous reports have been published on the acute effects of COVID-19 infection, the review explores the multifaceted long-term implications of COVID-19, with a particular focus on severe maternal COVID-19 infection, gut microbiome dysbiosis, and neurodevelopmental disorders in offspring. Severe COVID-19 infection has been associated with heightened immune system activation and gastrointestinal symptoms. Severe COVID-19 may also result in gut microbiome dysbiosis and a compromised intestinal mucosal barrier, often referred to as 'leaky gut'. Increased gut permeability facilitates the passage of inflammatory cytokines, originating from the inflamed intestinal mucosa and gut, into the bloodstream, thereby influencing fetal development during pregnancy and potentially elevating the risk of neurodevelopmental disorders such as autism and schizophrenia. The current review discusses the role of cytokine signaling molecules, microglia, and synaptic pruning, highlighting their potential involvement in the pathogenesis of neurodevelopmental disorders following maternal COVID-19 infection. Additionally, this review addresses the potential of probiotic interventions to mitigate gut dysbiosis and inflammatory responses associated with COVID-19, offering avenues for future research in optimizing maternal and fetal health outcomes.

Exploring the interaction and impact of probiotic and commensal bacteria on vitamins, minerals and short chain fatty acids metabolism

There is increasing evidence that probiotic and commensal bacteria play a role in substrate metabolism, energy harvesting and intestinal homeostasis, and may exert immunomodulatory activities on human health. In addition, recent research suggests that these microorganisms interact with vitamins and minerals, promoting intestinal and metabolic well-being while producing vital microbial metabolites such as short-chain fatty acids (SCFAs). In this regard, there is a flourishing field exploring the intricate dynamics between vitamins, minerals, SCFAs, and commensal/probiotic interactions. In this review, we summarize some of the major hypotheses beyond the mechanisms by which commensals/probiotics impact gut health and their additional effects on the absorption and metabolism of vitamins, minerals, and SCFAs. Our analysis includes comprehensive review of existing evidence from preclinical and clinical studies, with particular focus on the potential interaction between commensals/probiotics and micronutrients. Finally, we highlight knowledge gaps and outline directions for future research in this evolving field.

COVID-19 influenced gut dysbiosis, post-acute sequelae, immune regulation, and therapeutic regimens

The novel coronavirus disease 2019 (COVID-19) pandemic outbreak caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has garnered unprecedented global attention. It caused over 2.47 million deaths through various syndromes such as acute respiratory distress, hypercoagulability, and multiple organ failure. The viral invasion proceeds through the ACE2 receptor, expressed in multiple cell types, and in some patients caused serious damage to tissues, organs, immune cells, and the microbes that colonize the gastrointestinal tract (GIT). Some patients who survived the SARS-CoV-2 infection have developed months of persistent long-COVID-19 symptoms or post-acute sequelae of COVID-19 (PASC). Diagnosis of these patients has revealed multiple biological effects, none of which are mutually exclusive. However, the severity of COVID-19 also depends on numerous comorbidities such as obesity, age, diabetes, and hypertension and care must be taken with respect to other multiple morbidities, such as host immunity. Gut microbiota in relation to SARS-CoV-2 immunopathology is considered to evolve COVID-19 progression via mechanisms of biochemical metabolism, exacerbation of inflammation, intestinal mucosal secretion, cytokine storm, and immunity regulation. Therefore, modulation of gut microbiome equilibrium through food supplements and probiotics remains a hot topic of current research and debate. In this review, we discuss the biological complications of the physio-pathological effects of COVID-19 infection, GIT immune response, and therapeutic pharmacological strategies. We also summarize the therapeutic targets of probiotics, their limitations, and the efficacy of preclinical and clinical drugs to effectively inhibit the spread of SARS-CoV-2.

Association Between Altered Microbiota Composition and Immune System-Related Genes in COVID-19 Infection

Microbiota and immunity affect the host's susceptibility to SARS-CoV-2 infection and the severity of COVID-19. This study aimed to identify significant alterations in the microbiota composition, immune signaling pathways, their potential association, and candidate microRNA in COVID-19 patients using an in silico study model. Enrichment online databases and Python programming were utilized to analyze GSE164805, GSE180594, and GSE182279, as well as NGS data of microbiota composition (PRJNA650244 and PRJNA660302) associated with COVID-19, employing amplicon-based/marker gene sequencing methods. C1, TNF, C2, IL1, and CFH genes were found to have a significant impact on immune signaling pathways. Additionally, we observed a notable decrease in Bacteroides spp. and Faecalibacterium sp., while Escherichia coli, Streptococcus spp., and Akkermansia muciniphila showed increased abundance in COVID-19. Notably, A. muciniphila demonstrated an association with immunity through C1 and TNF, while Faecalibacterium sp. was linked to C2 and IL1. The correlation between E. coli and CFH, as well as IL1 and Streptococcus spp. with C2, was identified. hsa-let-7b-5p was identified as a potential candidate that may be involved in the interaction between the microbiota composition, immune response, and COVID-19. In conclusion, integrative in silico analysis shows that these microbiota members are potentially crucial in the immune responses against COVID-19.

Lymphocyte and neutrophil count combined with intestinal bacteria abundance predict the severity of COVID-19

IMPORTANCE

The 2019 coronavirus disease (COVID-19) patients had a unique profile of gut bacteria. In this study, we characterized the intestinal bacteria in our COVID-19 cohorts and found that there was an increased incidence of severe cases in COVID-19 patients with decreased lymphocytes and increased neutrophils. Levels of lymphocytes and neutrophils and abundances of intestinal bacteria correlated with the severity of COVID-19.

COVID-19-associated candidiasis and the emerging concern of Candida auris infections

The incidence of COVID-19-associated candidiasis (CAC) is increasing, resulting in a grave outcome among hospitalized patients with COVID-19. The most alarming condition is the increasing incidence of multi-drug resistant Candida auris infections among patients with COVID-19 worldwide. The therapeutic strategy towards CAC caused by common Candida species, such as Candida albicans, Candida tropicalis, and Candida glabrata, is similar to the pre-pandemic era. For non-critically ill patients or those with a low risk of azole resistance, fluconazole remains the drug of choice for candidemia. For critically ill patients, those with a history of recent azole exposure or with a high risk of fluconazole resistance, echinocandins are recommended as the first-line therapy. Several novel therapeutic agents alone or in combination with traditional antifungal agents for candidiasis are potential options in the future. However, for multidrug-resistant C. auris infection, only echinocandins are effective. Infection prevention and control policies, including strict isolation of the patients carrying C. auris and regular screening of non-affected patients, are suggested to prevent the spread of C. auris among patients with COVID-19. Whole-genome sequencing may be used to understand the epidemiology of healthcare-associated candidiasis and to better control and prevent these infections.

Could probiotics protect against human toxicity caused by polystyrene nanoplastics and microplastics?

Nanoplastics (NPs) and microplastics (MPs) made of polystyrene (PS) can be toxic to humans, especially by ingestion of plastic particles. These substances are often introduced into the gastrointestinal tract, where they can cause several adverse effects, including disturbances in intestinal flora, mutagenicity, cytotoxicity, reproductive toxicity, neurotoxicity, and exacerbated oxidative stress. Although there are widespread reports of the protective effects of probiotics on the harm caused by chemical contaminants, limited information is available on how these organisms may protect against PS toxicity in either humans or animals. The protective effects of probiotics can be seen in organs, such as the gastrointestinal tract, reproductive tract, and even the brain. It has been shown that both MPs and NPs could induce microbial dysbiosis in the gut, nose and lungs, and probiotic bacteria could be considered for both prevention and treatment. Furthermore, the improvement in gut dysbiosis and intestinal leakage after probiotics consumption may reduce inflammatory biomarkers and avoid unnecessary activation of the immune system. Herein, we show probiotics may overcome the toxicity of polystyrene nanoplastics and microplastics in humans, although some studies are required before any clinical recommendations can be made.

Effect of probiotics as an immune modulator for the management of COVID-19

COVID-19, an acute respiratory viral infection conveyed by pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected millions of individuals globally, and is a public health emergency of international concern. Till now, there are no highly effective therapies for this infection without vaccination. As they can evolve quickly and cross the strain level easily, these viruses are causing epidemics or pandemics that are allied with more severe clinical diseases. A new approach is needed to improve immunity to confirm the protection against emerging viral infections. Probiotics can modify gut microbial dysbiosis, improve the host immune system, and stimulate immune signaling, increasing systemic immunity. Several probiotic bacterial therapies have been proven to decrease the period of bacterial or viral infections. Superinduction of inflammation, termed cytokine storm, has been directly linked with pneumonia and severe complications of viral respiratory infections. In this case, probiotics as potential immunomodulatory agents can be an appropriate candidate to improve the host's response to respiratory viral infections. During this COVID-19 pandemic, any approach that can induce mucosal and systemic immunity could be helpful. Here, we summarize contexts regarding the effectiveness of various probiotics for preventing virus-induced respiratory infectious diseases, especially those that could be employed for COVID-19 patients. In addition, the effects of probiotics, their mechanisms on different aspects of immune responses against respiratory viral infection, and their antiviral properties in clinical findings have been described in detail.

Probiotics and Their Antimicrobial Effect

This Special Issue of the journal Microorganisms highlights the importance of the antimicrobial effect of probiotics [...].

Mapping the output of the global literature on the links between gut microbiota and COVID-19

BACKGROUND

The term "human microbiota" refers to populations of microorganisms that live harmoniously in co-existence with humans. They contribute significantly to the host's immunological response when confronted with a respiratory viral infection. However, little is known about the relationship between the human microbiome and COVID-19. Therefore, our objective is to perform a bibliometric analysis to explore the overall structure and hotspots of research activity on the links between microbiota and COVID-19 at the global level.

METHODS

The research literature on the microbiota and COVID-19 published between 2020 and 2022 was obtained from the Scopus database. Bibliometric analysis and network visualization were performed with VOSviewer.

RESULTS

Of the 701 publications selected, the USA contributed the most (n = 157, 22.40%), followed by China (n = 118, 16.83%) and Italy (n = 82, 11.70%). Hotspots in this field were "COVID-19 is associated with an altered upper respiratory tract microbiome," "the effect of antibiotics on the gut microbiome," as well as "patient nutrition and probiotic therapy in COVID-19."

CONCLUSIONS

The links between microbiota and COVID-19 remain an urgent concern at present, and the use of probiotics or/and antibiotics during the pandemic needs to be further improved. This landscape analysis of the links between the microbiota and COVID-19 will provide a basis for future research.

Alterations of the gut microbiota in coronavirus disease 2019 and its therapeutic potential

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a serious threat to global health. SARS-CoV-2 infects host cells primarily by binding to angiotensin-converting enzyme 2, which is coexpressed in alveolar type 2 cells and gut epithelial cells. It is known that COVID-19 often presents with gastrointestinal symptoms and gut dysbiosis, mainly characterized by an increase in opportunistic pathogens and a decrease in beneficial commensal bacteria. In recent years, multiple studies have comprehensively explored gut microbiota alterations in COVID-19 and highlighted the clinical correlation between dysbiosis and COVID-19. SARS-CoV-2 causes gastrointestinal infections and dysbiosis mainly through fecal-oral transmission and the circulatory and immune pathways. Studies have shown that the gut microbiota and its metabolites can regulate the immune response and modulate antiviral effects. In addition, the gut microbiota is closely related to gastrointestinal symptoms, such as diarrhea, a common gastrointestinal symptom among COVID-19. Therefore, the contribution of the gut microbiota in COVID-19 should not be overlooked. Strategies targeting the gut microbiota via probiotics, prebiotics and fecal microbiota transplantation should be considered to treat this patient population in the future. However, the specific alterations and mechanisms as well as the contributions of gut microbiota in COVID-19 should be urgently further explored.

Vitamin C improves gut Bifidobacteria in humans

Aims: Numerous beneficial effects of vitamin C (ascorbic acid) supplementation have been reported in the literature. However, data on its effects toward the gut microbiome are limited. We assessed the effect of vitamin C supplementation on the abundance of beneficial bacterial species in the gut microbiome. Materials and methods: Stool samples were analyzed for relative abundance of gut microbiome bacteria using next-generation sequencing-based profiling and metagenomic shotgun analysis. Results: Supplementation with vitamin C increased the abundance of bacteria of the genus Bifidobacterium (p = 0.0001) and affected various species. Conclusion: The beneficial effects of vitamin C supplementation may be attributed to modulation of the gut microbiome and the consequent health benefits thereof.

COVID-19 and Gut Injury

COVID-19 induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently a pandemic and it has led to more than 620 million patients with 6.56 million deaths globally. Males are more susceptible to COVID-19 infection and associated with a higher chance to develop severe COVID-19 than females. Aged people are at a high risk of COVID-19 infection, while young children have also increased cases. COVID-19 patients typically develop respiratory system pathologies, however symptoms in the gastrointestinal (GI) tract are also very common. Inflammatory cell recruitments and their secreted cytokines are found in the GI tract in COVID-19 patients. Microbiota changes are the key feature in COVID-19 patients with gut injury. Here, we review all current known mechanisms of COVID-19-induced gut injury, and the most acceptable one is that SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) receptor on host cells in the GI tract. Interestingly, inflammatory bowel disease (IBD) is an inflammatory disorder, but the patients with IBD do not have the increased risk to develop COVID-19. There is currently no cure for COVID-19, but anti-viruses and monoclonal antibodies reduce viral load and shorten the recovery time of the disease. We summarize current therapeutics that target symptoms in the GI tract, including probiotics, ACE2 inhibitors and nutrients. These are promising therapeutic options for COVID-19-induced gut injury.

Are Nutraceuticals Effective in COVID-19 and Post-COVID Prevention and Treatment?

The beginning of the end or the end of the beginning? After two years mastered by coronavirus disease 19 (COVID-19) pandemic, we are now witnessing a turnaround. The reduction of severe cases and deaths from COVID-19 led to increasing importance of a new disease called post-COVID syndrome. The term post-COVID is used to indicate permanency of symptoms in patients who have recovered from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Immune, antiviral, antimicrobial therapies, as well as ozone therapy have been used to treat COVID-19 disease. Vaccines have then become available and administered worldwide to prevent the insurgence of the disease. However, the pandemic is not over yet at all given the emergence of new omicron variants. New therapeutic strategies are urgently needed. In this view, great interest was found in nutraceutical products, including vitamins (C, D, and E), minerals (zinc), melatonin, probiotics, flavonoids (quercetin), and curcumin. This review summarizes the role of nutraceuticals in the prevention and/or treatment of COVID-19 disease and post-COVID syndrome.

SARS-CoV-2-associated gut microbiome alteration; A new contributor to colorectal cancer pathogenesis

The emergence of a novel coronavirus, COVID-19, in December 2019 led to a global pandemic with more than 170 million confirmed infections and more than 6 million deaths (by July 2022). Studies have shown that infection with SARS-CoV-2 in cancer patients has a higher mortality rate than in people without cancer. Here, we have reviewed the evidence showing that gut microbiota plays an important role in health and is linked to colorectal cancer development. Studies have shown that SARS-CoV-2 infection leads to a change in gut microbiota, which modify intestinal inflammation and barrier permeability and affects tumor-suppressor or oncogene genes, proposing SARS-CoV-2 as a potential contributor to CRC pathogenesis

Potential impact of COVID-19 pandemic on endometriosis

The impact of coronavirus disease 2019 (COVID-19) on endometriosis (EM) is currently unclear. Here, we aimed to describe the potential influence of COVID-19 on the pathogenesis, clinical symptoms, and treatment of EM. The cytokine storm caused by COVID-19 may induce the occurrence and progression of EM, and immunosuppression of COVID-19 may help the ectopic endometrium escape from immune clearance. Consequently, the forced social isolation and the cancelation of non-emergency medical treatment during the COVID-19 pandemic aggravate anxiety and psychological pressure, which can aggravate the symptoms related to EM and delay routine medical services.

Inflammatory pathways in COVID‐19: Mechanism and therapeutic interventions

The 2019 coronavirus disease (COVID‐19) pandemic has become a global crisis. In the immunopathogenesis of COVID‐19, SARS‐CoV‐2 infection induces an excessive inflammatory response in patients, causing an inflammatory cytokine storm in severe cases. Cytokine storm leads to acute respiratory distress syndrome, pulmonary and other multiorgan failure, which is an important cause of COVID‐19 progression and even death. Among them, activation of inflammatory pathways is a major factor in generating cytokine storms and causing dysregulated immune responses, which is closely related to the severity of viral infection. Therefore, elucidation of the inflammatory signaling pathway of SARS‐CoV‐2 is important in providing otential therapeutic targets and treatment strategies against COVID‐19. Here, we discuss the major inflammatory pathways in the pathogenesis of COVID‐19, including induction, function, and downstream signaling, as well as existing and potential interventions targeting these cytokines or related signaling pathways. We believe that a comprehensive understanding of the regulatory pathways of COVID‐19 immune dysregulation and inflammation will help develop better clinical therapy strategies to effectively control inflammatory diseases, such as COVID‐19.

Immunomodulatory Effects of Probiotics on COVID-19 Infection by Targeting the Gut–Lung Axis Microbial Cross-Talk

The ecosystem of the human gastrointestinal tract, named gut microbiota, represents the most thoroughly mapped ecosystem. Perturbations on bacterial populations cause dysbiosis, a condition correlated to a wide range of autoimmune, neurological, metabolic, cardiovascular, and respiratory diseases. The lungs have their flora, which are directly related to the gut flora via bidirectional communication allowing the transport of microbial metabolites and toxins produced by intestinal bacteria through the circulation and lymphatic system. This mutual microbial cross-talk communication called the gut–lung axis modulates the immune and inflammatory response to infections. COVID-19 causes dysbiosis, altered intestinal permeability, and bacterial translocation. Dysbiosis, through the gut–lung axis, promotes hyper-inflammation, exacerbates lung damage, and worsens clinical outcomes. Preclinical and clinical studies have shown that probiotics can regulate cytokine secretion, thus affecting both nonspecific and specific immunity. Probiotics act by blocking the virus from invading and proliferating in host cells, by stimulating the immune response, and by suppressing the activation of NLRP3 inflammasome. Herein, we reviewed the evidence from preclinical and clinical studies evaluating the effect of probiotics administration on the immune response to COVID-19 infection by targeting the gut–lung axis microbial cross-talk.

Pharmacological Efficacy of Probiotics in Respiratory Viral Infections: A Comprehensive Review

Mortality and morbidity from influenza and other respiratory viruses are significant causes of concern worldwide. Infections in the respiratory tract are often underappreciated because they tend to be mild and incapacitated. On the other hand, these infections are regarded as a common concern in clinical practice. Antibiotics are used to treat bacterial infections, albeit this is becoming more challenging since many of the more prevalent infection causes have acquired a wide range of antimicrobial resistance. Resistance to frontline treatment medications is constantly rising, necessitating the development of new antiviral agents. Probiotics are one of several medications explored to treat respiratory viral infection (RVI). As a result, certain probiotics effectively prevent gastrointestinal dysbiosis and decrease the likelihood of secondary infections. Various probiotic bacterias and their metabolites have shown immunomodulating and antiviral properties. Unfortunately, the mechanisms by which probiotics are effective in the fight against viral infections are sometimes unclear. This comprehensive review has addressed probiotic strains, dosage regimens, production procedures, delivery systems, and pre-clinical and clinical research. In particular, novel probiotics’ fight against RVIs is the impetus for this study. Finally, this review may explore the potential of probiotic bacterias and their metabolites to treat RVIs. It is expected that probiotic-based antiviral research would be benefitted from this review’s findings.

Altered gut microbiota patterns in COVID-19: Markers for inflammation and disease severity

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to a severe respiratory illness and alters the gut microbiota, which dynamically interacts with the human immune system. Microbiota alterations include decreased levels of beneficial bacteria and augmentation of opportunistic pathogens. Here, we describe critical factors affecting the microbiota in coronavirus disease 2019 (COVID-19) patients. These include, such as gut microbiota imbalance and gastrointestinal symptoms, the pattern of altered gut microbiota composition in COVID-19 patients, and crosstalk between the microbiome and the gut-lung axis/gut-brain-lung axis. Moreover, we have illustrated the hypoxia state in COVID-19 associated gut microbiota alteration. The role of ACE2 in the digestive system, and control of its expression using the gut microbiota is discussed, highlighting the interactions between the lungs, the gut, and the brain during COVID-19 infection. Similarly, we address the gut microbiota in elderly or co-morbid patients as well as gut microbiota dysbiosis of in severe COVID-19. Several clinical trials to understand the role of probiotics in COVID-19 patients are listed in this review. Augmented inflammation is one of the major driving forces for COVID-19 symptoms and gut microbiome disruption and is associated with disease severity. However, understanding the role of the gut microbiota in immune modulation during SARS-CoV-2 infection may help improve therapeutic strategies for COVID-19 treatment.

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.

Impact of the Gastrointestinal Tract Microbiota on Cardiovascular Health and Pathophysiology

ABSTRACT

The microbiota of the gastrointestinal tract (GIT) is an extremely diverse community of microorganisms, and their collective genomes (microbiome) provide a vast arsenal of biological activities, in particular enzymatic ones, which are far from being fully elucidated. The study of the microbiota (and the microbiome) is receiving great interest from the biomedical community as it carries the potential to improve risk-prediction models, refine primary and secondary prevention efforts, and also design more appropriate and personalized therapies, including pharmacological ones. A growing body of evidence, though sometimes impaired by the limited number of subjects involved in the studies, suggests that GIT dysbiosis, i.e. the altered microbial composition, has an important role in causing and/or worsening cardiovascular disease (CVD). Bacterial translocation as well as the alteration of levels of microbe-derived metabolites can thus be important to monitor and modulate, because they may lead to initiation and progression of CVD, as well as to its establishment as chronic state. We hereby aim to provide readers with details on available resources and experimental approaches that are used in this fascinating field of biomedical research, and on some novelties on the impact of GIT microbiota on CVD.

Neutrophil Extracellular Traps in Severe SARS-CoV-2 Infection: A Possible Impact of LPS and (1→3)-β-D-glucan in Blood from Gut Translocation

Due to limited data on the link between gut barrier defects (leaky gut) and neutrophil extracellular traps (NETs) in coronavirus disease 2019 (COVID-19), blood samples of COVID-19 cases—mild (upper respiratory tract symptoms without pneumonia; n = 27), moderate (pneumonia without hypoxia; n = 28), and severe (pneumonia with hypoxia; n = 20)—versus healthy control (n = 15) were evaluated, together with in vitro experiments. Accordingly, neutrophil counts, serum cytokines (IL-6 and IL-8), lipopolysaccharide (LPS), bacteria-free DNA, and NETs parameters (fluorescent-stained nuclear morphology, dsDNA, neutrophil elastase, histone–DNA complex, and myeloperoxidase–DNA complex) were found to differentiate COVID-19 severity, whereas serum (1→3)-β-D-glucan (BG) was different between the control and COVID-19 cases. Despite non-detectable bacteria-free DNA in the blood of healthy volunteers, using blood bacteriome analysis, proteobacterial DNA was similarly predominant in both control and COVID-19 cases (all severities). In parallel, only COVID-19 samples from moderate and severe cases, but not mild cases, were activated in vitro NETs, as determined by supernatant dsDNA, Peptidyl Arginine Deiminase 4, and nuclear morphology. With neutrophil experiments, LPS plus BG (LPS + BG) more prominently induced NETs, cytokines, NFκB, and reactive oxygen species, when compared with the activation by each molecule alone. In conclusion, pathogen molecules (LPS and BG) from gut translocation along with neutrophilia and cytokinemia in COVID-19-activated, NETs-induced hyperinflammation.

Oral Nirmatrelvir/Ritonavir Therapy for COVID-19: The Dawn in the Dark?

Nirmatrelvir/ritonavir (Paxlovid™) is an effective and safe antiviral drug that inhibits the main protease (M^pro), 3CL protease, of SARS-CoV-2. A reduction in COVID-19-related hospitalization or death was observed in patients treated with nirmatrelvir/ritonavir within five days of symptom onset. Moreover, good oral availability enables the usage of nirmatrelvir/ritonavir, not only in hospitalized patients, but also among outpatients. Nirmatrelvir (PF-07321332) has been demonstrated to stop the spread of COVID-19 in animal models. Despite frequent mutations in the viral genomes of SARS-CoV-2, nirmatrelvir shows an effective antiviral effect against recent coronavirus mutants. Despite the promising antiviral effect of nirmatrelvir, there are several unresolved concerns. First, the final results of large-scale clinical trials for early therapy of mild cases of COVID-19 are not yet published. Second, the effectiveness of nirmatrelvir against upcoming variants in the coming years requires close monitoring. Considering the promising preliminary results of the EPIC-HR trial, nirmatrelvir/ritonavir in conjunction with vaccines and non-pharmacological interventions, may represent the dawn in the dark of the COVID-19 pandemic.

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.

Short-chain fatty acids-microbiota crosstalk in the coronavirus disease (COVID-19)

The novel coronavirus disease (COVID-19) still remains a major challenge to the health-care systems worldwide, inciting ongoing search for pharmaceutical and non-pharmaceutical interventions which could benefit patients already infected with SARS-CoV-2 or at increased risk thereof. Although SARS-CoV-2 primarily affects the respiratory system, it may also infect other organs and systems, including gastrointestinal tract, where it results in microbial dysbiosis. There is an emerging understanding of the role the gut microbiota plays in maintaining immune homeostasis, both inside the gastrointestinal tract and beyond (i.e. through gut-lung and gut-brain axes). One family of compounds with recognized immunomodulatory and anti-inflammatory properties are short chain fatty acids (SCFAs). SCFAs are believed that they have a protective effect in case of gastrointestinal diseases. Moreover, they are responsible for maintaining proper intestinal barrier and they take part in relevant immune functions. This review presents mechanisms of action and potential benefits of SCFA-based probiotics and direct SCFA supplementation as a strategy to support immune function amid the COVID-19 pandemic.

Intestinal microbiota composition of children with infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and multisystem inflammatory syndrome (MIS-C)

Microbiota composition may play a role in the development, prognosis, or post-infection of COVID-19. There are studies evaluating the microbiota composition at the time of diagnosis and during the course of COVID-19, especially in adults, while studies in children are limited and no study available in children with multisystem inflammatory syndrome in children (MIS-C). This study was planned to compare intestinal microbiota composition in children diagnosed with MIS-C and acute COVID-19 infection with healthy children. In this prospective multicenter study, 25 children diagnosed with MIS-C, 20 with COVID-19 infection, and 19 healthy children were included. Intestinal microbiota composition was evaluated by 16 s rRNA gene sequencing. We observed changes of diversity, richness, and composition of intestinal microbiota in MIS-C cases compared to COVID-19 cases and in the healthy controls. The Shannon index was higher in the MIS-C group than the healthy controls (p < 0.01). At phylum level, in the MIS-C group, a significantly higher relative abundance of Bacteroidetes and lower abundance of Firmicutes was found compared to the control group. Intestinal microbiota composition changed in MIS-C cases compared to COVID-19 and healthy controls, and Faecalibacterium prausnitzii decreased; Bacteroides uniformis, Bacteroides plebeius, Clostridium ramosum, Eubacterium dolichum, Eggerthella lenta, Bacillus thermoamylovorans, Prevotella tannerae, and Bacteroides coprophilus were dominant in children with MIS-C. At species level, we observed decreased Faecalibacterium prausnitzii, and increased Eubacterium dolichum, Eggerthella lenta, and Bacillus thermoamylovorans in children with MIS-C and increased Bifidobacterium adolescentis and Dorea formicigenerasus in the COVID-19 group. Our study is the first to evaluate the microbiota composition in MIS-C cases. There is a substantial change in the composition of the gut microbiota: (1) reduction of F. prausnitzii in children with MIS-C and COVID-19; (2) an increase of Eggerthella lenta which is related with autoimmunity; and (3) the predominance of E. dolichum is associated with metabolic dysfunctions and obesity in children with MIS-C.

CONCLUSIONS

 Alterations of the intestinal microbiota might be part of pathogenesis of predisposing factor for MIS-C. It would be beneficial to conduct more extensive studies on the cause-effect relationship of these changes in microbiota composition and their effects on long-term prognosis.

WHAT IS KNOWN

• Microbiota composition may play a role in the development, prognosis, or post-infection of COVID-19.  • However, the number of studies on children is limited, and no study on multisystem inflammatory syndrome in children is currently available (MIS-C).

WHAT IS NEW

• In individuals with MIS-C, the composition of the gut microbiota changed dramatically. • Decreased Faecalibacterium prausnitzii have been observed, increased Eggerthella lenta, which was previously linked to autoimmunity, and predominance of Eubacterium dolichum which was linked to metabolic dysfunction and obesity.

Patient Nutrition and Probiotic Therapy in COVID-19: What Do We Know in 2021?

BACKGROUND

The main nutritional consequences of COVID-19 include reduced food intake, hypercatabolism, and rapid muscle wasting. Some studies showed that malnutrition is a significant problem among patients hospitalized due to COVID-19 infection, and the outcome of patients with SARS-CoV-2 is strongly associated with their nutritional status. The purpose of this study was to collect useful information about the possible elements of nutritional and probiotic therapy in patients infected with the SARS-CoV-2 virus.

METHODS

A narrative review of the literature, including studies published up to 13 September 2021.

RESULTS

Probiotics may support patients by inhibiting the ACE2 receptor, i.e., the passage of the virus into the cell, and may also be effective in suppressing the immune response caused by the proinflammatory cytokine cascade. In patients' diet, it is crucial to ensure an adequate intake of micronutrients, such as omega-3 fatty acids (at 2-4 g/d), selenium (300-450 μg/d) and zinc (30-50 mg/d), and vitamins A (900-700 µg/d), E (135 mg/d), D (20,000-50,000 IU), C (1-2 g/d), B6, and B12. Moreover, the daily calorie intake should amount to ≥1500-2000 with 75-100 g of protein.

CONCLUSION

In conclusion, the treatment of gut dysbiosis involving an adequate intake of prebiotic dietary fiber and probiotics could turn out to be an immensely helpful instrument for immunomodulation, both in COVID-19 patients and prophylactically in individuals with no history of infection.