Intestinal permeability changes with bacterial translocation as key events modulating systemic host immune response to SARS-CoV-2: A working hypothesis

COVID-19-associated encephalopathy: connection between neuroinflammation and microbiota-gut-brain axis

While neurological complications of COVID-19, such as encephalopathy, are relatively rare, their potential significant impact on long-term morbidity is substantial, especially given the large number of infected patients. Two proposed hypotheses for the pathogenesis of this condition are hypoxia and the uncontrolled release of proinflammatory cytokines. The gut microbiota plays an important role in regulating immune homeostasis and overall gut health, including its effects on brain health through various pathways collectively termed the gut-brain axis. Recent studies have shown that COVID-19 patients exhibit gut dysbiosis, but how this dysbiosis can affect inflammation in the central nervous system (CNS) remains unclear. In this context, we discuss how dysbiosis could contribute to neuroinflammation and provide recent data on the features of neuroinflammation in COVID-19 patients.

Critical COVID-19, Victivallaceae abundance, and celiac disease: A mediation Mendelian randomization study

Celiac disease exhibits a higher prevalence among patients with coronavirus disease 2019. However, the potential influence of COVID-19 on celiac disease remains uncertain. Considering the significant association between gut microbiota alterations, COVID-19 and celiac disease, the two-step Mendelian randomization method was employed to investigate the genetic causality between COVID-19 and celiac disease, with gut microbiota as the potential mediators. We employed the genome-wide association study to select genetic instrumental variables associated with the exposure. Subsequently, these variables were utilized to evaluate the impact of COVID-19 on the risk of celiac disease and its potential influence on gut microbiota. Employing a two-step Mendelian randomization approach enabled the examination of potential causal relationships, encompassing: 1) the effects of COVID-19 infection, hospitalized COVID-19 and critical COVID-19 on the risk of celiac disease; 2) the influence of gut microbiota on celiac disease; and 3) the mediating impact of the gut microbiota between COVID-19 and the risk of celiac disease. Our findings revealed a significant association between critical COVID-19 and an elevated risk of celiac disease (inverse variance weighted [IVW]: P = 0.035). Furthermore, we observed an inverse correlation between critical COVID-19 and the abundance of Victivallaceae (IVW: P = 0.045). Notably, an increased Victivallaceae abundance exhibits a protective effect against the risk of celiac disease (IVW: P = 0.016). In conclusion, our analysis provides genetic evidence supporting the causal connection between critical COVID-19 and lower Victivallaceae abundance, thereby increasing the risk of celiac disease.

The association between tocilizumab and the secondary bloodstream infection maybe nonsignificant in hospitalized patients with SARS-CoV-2 infection: A cohort study

BACKGROUND

Immunomodulatory agents, such as tocilizumab (TCZ), exert promising effects against SARS-CoV-2 infection. However, growing evidence indicates that using TCZ may carry higher risks of secondary bloodstream infection (sBSI). This study determined whether TCZ is associated with an increased risk of sBSI.

METHODS

We retrospectively collected the demographic and clinical data of hospitalized patients with SARS-CoV-2 infection from two Taiwanese hospitals. The time-to-incident sBSI in the TCZ users and nonusers was compared using the log-rank test. A multivariate Cox proportional hazards model was performed to identify independent risk factors for sBSI.

RESULTS

Between May 1 and August 31, 2021, among 453 patients enrolled, 12 (2.65 %) developed sBSI. These patients were in hospital for longer duration (44.2 ± 31.4 vs. 17.6 ± 14.3 days, p = 0.014). Despite sBSI being more prevalent among the TCZ users (7.1 % vs. 1.6 %, p = 0.005), Kaplan-Meier survival analysis and multivariate Cox proportional hazards model both revealed no significant difference in risks of sBSI between the TCZ users and nonusers [adjusted HR (aHR) = 1.32 (95 % confidence interval (CI) = 0.29-6.05), p = 0.724]. Female sex [aHR = 7.00 (95 % CI = 1.45-33.92), p = 0.016], heavy drinking [aHR = 5.39 (95 % CI = 1.01-28.89), p = 0.049], and mechanical ventilation [aHR = 5.65 (95 % CI = 1.67-19.30), p = 0.006] were independently associated with a higher sBSI risk.

CONCLUSION

This real-world evidence indicates that in hospitalized patients with SARS-CoV-2 infection, TCZ does not significantly increase the risk of sBSI.

The incidence and predisposing factors for irritable bowel syndrome following COVID-19: a systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) disorder. Several studies have analyzed the long-term GI symptoms and IBS following coronavirus disease 2019 (COVID-19). The purpose of this study is to evaluate the incidence and predisposing factors for IBS following COVID-19 by a systematic review and meta-analysis.

METHODS

Electronic databases were searched to identify relevant studies. Primary outcomes were the pooled incidence rate of IBS following COVID-19 and the pooled relative risk (RR) for IBS in the COVID-19 group compared to the non-COVID-19 group. Secondary outcomes were the pooled RR and the standardized mean difference (SMD) for predisposing factors in the IBS group compared to the non-IBS group. Heterogeneity was evaluated using Cochran's Q test and I2 statistics.

RESULTS

Ten studies were included in this study. The pooled incidence rate of IBS in COVID-19 patients was 12%. The pooled incidence rate of IBS-D, IBS-C and IBS-M was 5%, 2% and 1%. The pooled incidence rate of IBS in 6 and 12 months was 10% and 3%. The pooled RR for IBS in COVID-19 patients was 1.23 [95% confidence interval (CI) = 0.50-3.01] compared to non-COVID-19 patients. The pooled RR or SMD for mild, moderate, and severe disease activity, procalcitonin (PCT), depression or anxiety in IBS patients following COVID-19 was 0.94 (95% CI = 0.74-1.21), 1.19 (95% CI = 0.65-2.21), 1.30 (95% CI = 0.63-2.66), 6.73 (95% CI = 6.08-7.38) and 3.21 (95% CI = 1.79-5.75).

CONCLUSION

The incidence of IBS following COVID-19 was 12%. But it was not higher than the general population. We also found some predisposing factors for IBS including depression or anxiety, PCT.

Fecal Microbiota Transplantation as Emerging Treatment in European Countries 2.0

Clostridioides difficile infection (CDI) is one of the most common healthcare-associated infections and one of the leading causes of morbidity and mortality in hospitalized patients in the world. Although several antibiotics effectively treat CDI, some individuals may not respond to these drugs and may be cured by transplanting stool from healthy donors. FMT has demonstrated extraordinary cure rates for the cure of CDI recurrences.Moreover, FMT has also been investigated in other disorders associated with the alteration of gut microbiota, such as inflammatory bowel disease (IBD), where the alterations of the gut microbiota ecology have been theorized to play a causative role. Although FMT is currently not recommended to cure IBD patients in clinical practice, several studies have been recently carried out with the ultimate goal to search new therapeutic options to patients.This review summarizes data on the use of FMT for the treatment of both CDI and IBD, with a special attention to highlight studies conducted in European countries.

Gut microbiota and immunotherapy of renal cell carcinoma

The gut microbiome has recently been proposed as a key player in cancer development and progression. Several studies have reported that the composition of the gut microbiome plays a role in the response to immune checkpoint inhibitors (ICIs). The gut microbiome modulation has been investigated as a potential therapeutic strategy for cancer, mainly in patients undergoing therapy with ICIs. In particular, modulation through probiotics, FMT or other microbiome-related approaches have proven effective to improve the response to ICIs. In this review, we examine the role of the gut microbiome in enhancing clinical responses to ICIs in the treatment of renal cancer.

The role of faecal microbiota transplantation in chronic noncommunicable disorders

The gut microbiome plays a key role in influencing several pathways and functions involved in human health, including metabolism, protection against infection, and immune regulation. Perturbation of the gut microbiome is recognised as a pathogenic factor in several gastrointestinal and extraintestinal disorders, and is increasingly considered as a therapeutic target in these conditions. Faecal microbiota transplantation (FMT) is the transfer of the microbiota from healthy screened stool donors into the gut of affected patients, and is a well-established and highly effective treatment for recurrent Clostridioides difficile infection. Despite the mechanisms of efficacy of FMT not being fully understood, it has been investigated in several chronic noncommunicable disorders, with variable results. This review aims to give an overview of mechanisms of efficacy of FMT in chronic noncommunicable disorders, and to paint the current landscape of its investigation in these medical conditions, including inflammatory bowel disease (IBD), chronic liver disorders, and also extraintestinal autoimmune conditions.

Gastrointestinal involvement in post-acute Coronavirus disease (COVID)-19 syndrome

PURPOSE OF REVIEW

Ten percentage of patients with coronavirus disease (COVID)-19 report having gastrointestinal (GI) symptoms as severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) not only infects the pulmonary but also the GI tract. GI infections including that due to viral infection is known to cause postinfection disorders of gut-brain interaction (DGBI); hence, we wish to review the long-term GI consequences following COVID-19, particularly post-COVID-19 DGBI.

RECENT FINDINGS

At least 12 cohort studies, four of which also included controls documented the occurrence of post-COVID-19 DGBI, particularly IBS following COVID-19. The risk factors for post-COVID-19 DGBI included female gender, symptomatic COVID-19, particularly GI symptoms, the severity of COVID-19, the occurrence of anosmia and ageusia, use of antibiotics and hospitalization during the acute illness, persistent GI symptoms beyond 1 month after recovery, presence of mental health factors, The putative mechanisms for post-COVID-19 DGBI include altered gut motility, visceral hypersensitivity, gut microbiota dysbiosis, GI inflammation, and immune activation, changes in intestinal permeability, and alterations in the enteroendocrine system and serotonin metabolism.

SUMMARY

Long-term sequelae of SARS-CoV2 infection may persist even after recovery from COVID-19. Patients with COVID-19 are more likely to develop post-COVID-19 IBS than healthy controls. Post-COVID-19 IBS may pose a substantial healthcare burden to society.

Gut-brain pathogenesis of post-acute COVID-19 neurocognitive symptoms

Approximately one third of non-hospitalized coronavirus disease of 2019 (COVID-19) patients report chronic symptoms after recovering from the acute stage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Some of the most persistent and common complaints of this post-acute COVID-19 syndrome (PACS) are cognitive in nature, described subjectively as "brain fog" and also objectively measured as deficits in executive function, working memory, attention, and processing speed. The mechanisms of these chronic cognitive sequelae are currently not understood. SARS-CoV-2 inflicts damage to cerebral blood vessels and the intestinal wall by binding to angiotensin-converting enzyme 2 (ACE2) receptors and also by evoking production of high levels of systemic cytokines, compromising the brain's neurovascular unit, degrading the intestinal barrier, and potentially increasing the permeability of both to harmful substances. Such substances are hypothesized to be produced in the gut by pathogenic microbiota that, given the profound effects COVID-19 has on the gastrointestinal system, may fourish as a result of intestinal post-COVID-19 dysbiosis. COVID-19 may therefore create a scenario in which neurotoxic and neuroinflammatory substances readily proliferate from the gut lumen and encounter a weakened neurovascular unit, gaining access to the brain and subsequently producing cognitive deficits. Here, we review this proposed PACS pathogenesis along the gut-brain axis, while also identifying specific methodologies that are currently available to experimentally measure each individual component of the model.

Risk factors for carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infections and related mortality in critically ill patients with CRAB colonization

Background

Among MDR bacteria, carbapenem-resistant Acinetobacter baumannii (CRAB) is a major concern due to the limited therapeutic options. During the COVID-19 pandemic, a worrying increase in the spread of CRAB infections was reported.

Objectives

The study assessed the risk factors for CRAB bloodstream infection (BSI) in patients admitted to the ICU with CRAB colonization, and the related mortality risk factors.

Methods

We conducted a single-centre, observational, prospective study; all consecutive patients with CRAB colonization admitted to the ICU of a tertiary hospital in Rome from January 2021 to September 2022 were included in the study. Univariate and multivariate analyses were performed to investigate BSI and mortality risk factors.

Results

Overall, 129 patients were included in the study; 57 (44%) out of these developed BSI. In our study population, at the multivariable analysis the Charlson comorbidity index (CCI) (P = 0.026), COVID-19 (P < 0.001), multisite colonization (P = 0.016) and the need for mechanical ventilation (P = 0.024) were risk factors independently associated with BSI development. Furthermore, age (P = 0.026), CCI (P < 0.001), septic shock (P = 0.001) and Pitt score (P < 0.001) were independently associated with mortality in the BSI patients. Instead, early appropriate therapy (P = 0.002) and clinical improvement within 72 h (P = 0.011) were shown to be protective factors.

Conclusions

In critically ill patients colonized by CRAB, higher CCI, multisite colonization and the need for mechanical ventilation were identified as risk factors for BSI onset. These predictors could be useful to identify patients at highest risk of BSI.

Gut Microbiota Dysbiosis in COVID-19: Modulation and Approaches for Prevention and Therapy

Inflammation and oxidative stress are critical underlying mechanisms associated with COVID-19 that contribute to the complications and clinical deterioration of patients. Additionally, COVID-19 has the potential to alter the composition of patients' gut microbiota, characterized by a decreased abundance of bacteria with probiotic effects. Interestingly, certain strains of these bacteria produce metabolites that can target the S protein of other coronaviruses, thereby preventing their transmission and harmful effects. At the same time, the presence of gut dysbiosis can exacerbate inflammation and oxidative stress, creating a vicious cycle that perpetuates the disease. Furthermore, it is widely recognized that the gut microbiota can metabolize various foods and drugs, producing by-products that may have either beneficial or detrimental effects. In this regard, a decrease in short-chain fatty acid (SCFA), such as acetate, propionate, and butyrate, can influence the overall inflammatory and oxidative state, affecting the prevention, treatment, or worsening of COVID-19. This review aims to explore the current evidence regarding gut dysbiosis in patients with COVID-19, its association with inflammation and oxidative stress, the molecular mechanisms involved, and the potential of gut microbiota modulation in preventing and treating SARS-CoV-2 infection. Given that gut microbiota has demonstrated high adaptability, exploring ways and strategies to maintain good intestinal health, as well as an appropriate diversity and composition of the gut microbiome, becomes crucial in the battle against COVID-19.

Gastrointestinal microbiome of ARDS patients induces neuroinflammation and cognitive impairment in mice

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a respiratory failure syndrome that can cause many complications, impacting patients' quality of life. Behavioral and cognitive disorders have attracted increasing attention in patients with ARDS, but its potential mechanisms are still elusive.

METHODS

Herein we transferred the faecal microbiota from patients with ARDS caused by community-acquired pneumonia (CAP) to antibiotics-treated recipient male mice to explore the microbiota-gut-brain mechanisms. Behavioral functions of mice were evaluated by the open field test, Morris water maze and Y-maze test. The structure and composition of the gut microbiota were analyzed by using 16S rRNA sequencing analysis. Microglia, astrocyte and neuron in the cortex and hippocampus were examined via immunofluorescent staining.

RESULTS

We found that the major characteristic of the intestinal flora in ARDS/CAP patients was higher abundances of Gram-negative bacteria than normal controls. The gut microbiota derived from ARDS/CAP patients promoted neuroinflammation and behavioral dysfunctions in mice. Mice who underwent fecal transplant from ARDS/CAP patients had increased systemic lipopolysaccharide (LPS), systemic inflammation, and increased colonic barrier permeability. This may adversely impact blood barrier permeability and facilitate microglia activation, astrocyte proliferation, and loss of neurons.

CONCLUSIONS

Our study proposes the role of the microbiota-gut-brain crosstalk on ARDS/CAP-associated behavioral impairments and suggests the gut microbiota as a potential target for the protection of brain health in ARDS patients in clinical practice.

Histamine-producing bacteria and their role in gastrointestinal disorders

INTRODUCTION

Gut microbiota produces thousands of metabolites, which have a huge impact on the host health. Specific microbial strains are able to synthesize histamine, a molecule with a crucial role in many physiologic and pathologic mechanisms of the host. This function is mediated by the histidine decarboxylase enzyme (HDC) that converts the amino acid histidine to histamine.

AREAS COVERED

This review summarizes the emerging data on histamine production by gut microbiota, and the effect of bacterial-derived histamine in different clinical contexts, including cancer, irritable bowel syndrome, and other gastrointestinal and extraintestinal pathologies. This review will also outline the impact of histamine on the immune system and the effect of probiotics that can secrete histamine. Search methodology: we searched the literature on PubMed up to February 2023.

EXPERT OPINION

The potential of modulating gut microbiota to influence histamine production is a promising area of research, and although our knowledge of histamine-secreting bacteria is still limited, recent advances are exploring their diagnostic and therapeutical potential. Diet, probiotics, and pharmacological treatments directed to the modulation of histamine-secreting bacteria may in the future potentially be employed in the prevention and management of several gastrointestinal and extraintestinal disorders.

The Spectrum of Digestive Tract Histopathologic Findings in the Setting of Severe Acute Respiratory Syndrome Coronavirus-2 Infection: What Pathologists Need to Know

Although the novel severe acute respiratory syndrome coronavirus-2 is known primarily to affect the respiratory system, current evidence supports its capability to infect and induce gastrointestinal tract injury. Data describing the histopathologic alterations of the digestive system in patients infected with severe acute respiratory syndrome coronavirus-2 are becoming more detailed, as the number of studies is increasing and the quality of our insight into the infection and the histopathologic findings is improving. This review highlights the range of pathologic findings that could be observed in gastrointestinal specimens from patients infected with coronavirus disease 2019 and the potential underlying pathogenetic mechanisms of this disease.

Paralytic Ileus as an Extra-Pulmonary Manifestation of COVID-19

Extra-pulmonary manifestations of COVID-19 (SARS-CoV-2) are of increasing interest as a consequence of the increase in cases worldwide and a better understanding of the pathophysiology of the disease. However, gastrointestinal symptoms are rarely described but are a common occurrence. We report a case of a 62-year-old male with severe pulmonary infection with COVID-19, who presented with abdominal pain, hematemesis, bloody diarrhea, and abdominal distention, which led to the diagnosis of paralytic ileus after diagnostic laparoscopy. Further, we discuss the potential pathophysiological mechanisms behind this manifestation of COVID-19.

The role of diet in shaping human gut microbiota

Gut microbiota plays a fundamental role within human health, and exerts key functions within the human body. Diet is one of the most powerful modulators of gut microbiota functions and composition. This complex interplay involves also the immune system and the intestinal barrier, highlighting the central role of diet in the pathogenesis and treatment of multiple diseases. In this review article we will paint the landscape of the effects of specific dietary nutrients, and of the detrimental or beneficial outcomes of different dietary patterns, on the composition of human gut microbiota. Moreover, we will discuss the potential application of diet as a therapeutic modulator of gut microbiota, including cutting-edge ways of exploitation, including the use of dietary components as adjuvants to promote microbial engraftment after fecal microbiota transplantation, or personalized nutritional approaches, targeted to the patient microbiome.

Alterations in Gut Microbiota Composition in Patients with COVID-19: A Pilot Study of Whole Hypervariable 16S rRNA Gene Sequencing

It is crucial to consider the importance of the microbiome and the gut-lung axis in the context of SARS-CoV-2 infection. This pilot study examined the fecal microbial composition of patients with COVID-19 following a 3-month recovery. Using for the first time metagenomic analysis based on all hypervariable regions (V1-V9) of the 16S rRNA gene, we have identified 561 microbial species; however, 17 were specific only for the COVID-19 group (n = 8). The patients' cohorts revealed significantly greater alpha diversity of the gut microbiota compared to healthy controls (n = 14). This finding has been demonstrated by operational taxonomic units (OTUs) richness (p < 0.001) and Chao1 index (p < 0.01). The abundance of the phylum Verrucomicrobia was 30 times higher in COVID-19 patients compared to healthy subjects. Accordingly, this disproportion was also noted at other taxonomic levels: in the class Verrucomicrobiae, the family Verrucomicrobiaceae, and the genus Akkermansia. Elevated pathobionts such as Escherichia coli, Bilophila wadsworthia, and Parabacteroides distasonis were found in COVID-19 patients. Considering the gut microbiota's ability to disturb the immune response, our findings suggest the importance of the enteric microbiota in the course of SARS-CoV-2 infection. This pilot study shows that the composition of the microbial community may not be fully restored in individuals with SARS-CoV-2 following a 3-month recovery.

Commercial probiotic products in public health: current status and potential limitations

Consumption of commercial probiotics for health improvement and disease treatment has increased in popularity among the public in recent years. The local shops and pharmacies are brimming with various probiotic products such as probiotic food, dietary supplement and pharmaceuticals that herald a range of health benefits, from nutraceutical benefits to pharmaceutical effects. However, although the probiotic market is expanding rapidly, there is increasing evidence challenging it. Emerging insights from microbiome research and public health demonstrate several potential limitations of the natural properties, regulatory frameworks, and market consequences of commercial probiotics. In this review, we highlight the potential safety and performance issues of the natural properties of commercial probiotics, from the genetic level to trait characteristics and probiotic properties and further to the probiotic-host interaction. Besides, the diverse regulatory frameworks and confusing probiotic guidelines worldwide have led to product consequences such as pathogenic contamination, overstated claims, inaccurate labeling and counterfeit trademarks for probiotic products. Here, we propose a plethora of available methods and strategies related to strain selection and modification, safety and efficacy assessment, and some recommendations for regulatory agencies to address these limitations to guarantee sustainability and progress in the probiotic industry and improve long-term public health and development.

SARS-CoV-2 Vaccines: Types, Working Principle, and Its Impact on Thrombosis and Gastrointestinal Disorders

In the current scenario of the coronavirus pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), considerable efforts have been made to control the pandemic by the development of a strong immune system through massive vaccination. Just after the discovery of the genetic sequences of SARS-CoV-2, the development of vaccines became the prime focus of scientists around the globe. About 200 SARS-CoV-2 candidate vaccines have already been entered into preclinical and clinical trials. Various traditional and novel approaches are being utilized as a broad range of platforms. Viral vector (replicating and non-replicating), nucleic acid (DNA and RNA), recombinant protein, virus-like particle, peptide, live attenuated virus, an inactivated virus approaches are the prominent attributes of the vaccine development. This review article includes the current knowledge about the platforms used for the development of different vaccines, their working principles, their efficacy, and the impacts of COVID-19 vaccines on thrombosis. We provide a detailed description of the vaccines that are already approved by administrative authorities. Moreover, various strategies utilized in the development of emerging vaccines that are in the trial phases along with their mode of delivery have been discussed along with their effect on thrombosis and gastrointestinal disorders.

Zuogui-Jiangtang-Qinggan-Fang alleviates high-fat diet-induced type 2 diabetes mellitus with non-alcoholic fatty liver disease by modulating gut microbiome-metabolites-short chain fatty acid composition

Non-alcoholic fatty liver disease (NAFLD) pathogenesis is affected by dysbiosis of the gut microbiome and the metabolites it generates. Therefore, restoring the equilibrium between the gut microbiome and the generated metabolites may have therapeutic potential for the syndrome. Zuogui Jiangtang Qinggan Fang (ZGJTQGF) is a Chinese herbal formulation used clinically to treat type 2 diabetic mellitus (T2DM) and fatty liver disease. However, its pharmacological mechanisms have not been well characterized. This work aimed to evaluate the hepatoprotective mechanism of ZGJTQGF in T2DM with NAFLD mice by incorporating gut microbiota, short-chain fatty acids（SCFAs）, and metabolomic analysis, and then to provide strong support for clinical treatment of T2DM with NAFLD. The sequencing of 16 S rRNA revealed that ZGJTQGF therapy modified the composition and abundance of the gut microbiome, raised the level of SCFAs, and restored the intestinal mucosal barrier. The non-targeted metabolomic analysis of liver tissues identified 212 compounds, of which108 were differentially expressed between the HFD and ZGJTQGF groups. Moreover, L-glutamic acid, L-Phenylalanine, Glycine, Taurine, Deoxycholic acid, and citric acid levels were also considerably altered by ZGJTQGF. Our findings suggest that ZGJTQGF ameliorates HFD-induced hepatic steatosis by modulating the gut microbiota composition and its metabolites and boosting the levels of SCFAs. More notably, ZGJTQGF may be a promising medication for preventing and treating NAFLD.

Impact of Diet on Gut Microbiota Composition and Microbiota-Associated Functions in Heart Failure: A Systematic Review of In Vivo Animal Studies

Heart failure (HF) represents a cardiovascular disease with high mortality and morbidity. The latest evidence shows that changes in the composition of the gut microbiota might play a pivotal role in the prevention and management of HF. This systematic review aims at assessing the potential associations between the diet, gut microbiota, and derived metabolites with the outcomes of HF. A systematic literature search was performed up to July 2022 on the PubMed, Web of Science, and Scopus databases. The PRISMA guidelines were followed when possible. The risk of bias was assessed with the SYRCLE and ARRIVE tools. A total of nine pre-clinical studies on animal models, with considerable heterogeneity in dietary interventions, were included. High-fiber/prebiotic diets (n = 4) and a diet rich in polyphenols (n = 1) modified the gut microbiota composition and increased microbial metabolites' activities, linked with an improvement in HF outcomes, such as a reduction in systolic blood pressure, cardiac hypertrophy, and left ventricular thickness. A high-fat diet (n = 2) or a diet rich in choline (n = 2) induced an increase in TMAO and indole derivative production associated with a decrease in cardiac function, systemic endotoxemia, and inflammation and an increase in cardiac fibrosis and cardiac remodeling. Although results are retrieved from animal studies, this systematic review shows the key role of the diet-especially a high-fiber and prebiotic diet-on gut microbial metabolites in improving HF outcomes. Further studies on human cohorts are needed to identify personalized therapeutic dietary interventions to improve cardiometabolic health.

The Gut Microbiome of Children during the COVID-19 Pandemic

The gut microbiome has been shown to play a critical role in maintaining a healthy state. Dysbiosis of the gut microbiome is involved in modulating disease severity and potentially contributes to long-term outcomes in adults with COVID-19. Due to children having a significantly lower risk of severe illness and limited sample availability, much less is known about the role of the gut microbiome in children with COVID-19. It is well recognized that the developing gut microbiome of children differs from that of adults, but it is unclear if this difference contributes to the different clinical presentations and complications. In this review, we discuss the current knowledge of the gut microbiome in children with COVID-19, with gut microbiome dysbiosis being found in pediatric COVID-19 but specific taxa change often differing from those described in adults. Additionally, we discuss possible mechanisms of how the gut microbiome may mediate the presentation and complications of COVID-19 in children and the potential role for microbial therapeutics.

Oral intake of Kluyveromyces marxianus B0399 plus Lactobacillus rhamnosus CECT 30579 to mitigate symptoms in COVID-19 patients: A randomized open label clinical trial

At the beginning of the SARS-CoV-2 pandemic, developing of new treatments to control the spread of infection and decrease morbidity and mortality are necessary. This prospective, open-label, case-control intervention study evaluates the impact of the oral intake of the probiotic yeast Kluyveromyces marxianus B0399 together with Lactobacillus rhamnosus CECT 30579, administered for 30 days, on the evolution of COVID-19 patients. Analysis of the digestive symptoms at the end of the follow up shows a benefit of the probiotic in the number of patients without pyrosis (100% vs 33.3%; p 0.05) and without abdominal pain (100% vs 62.5%; p 0.04). Results also show a better evolution when evaluating the difference in the overall number of patients without non-digestive symptoms at the end of the follow-up (41.7%, vs 13%; p 0.06). The percentage of improvement in the digestive symptoms (65% vs 88%; p value 0.06) and the global symptoms (digestive and non-digestive) (88.6% vs 70.8%; p value 0.03) is higher in the probiotic group. The probiotic was well tolerated with no relevant side effects and high adherence among patients. In conclusion, this coadjutant treatment seems to be promising, although results should be confirmed in new studies with higher number of patients.

Anti-Saccharomyces cerevisiae antibodies in patients with COVID-19

BACKGROUND AND STUDY AIM

Anti-Saccharomyces cerevisiae antibodies (ASCA) have been described in many autoimmune diseases (AIDs). Coronavirus disease 2019 (COVID-19) could trigger AIDs. This study aimed to determine the frequency of ASCA in patients with COVID-19.

PATIENTS AND METHODS

This study included 88 adult patients with severe COVID-19, 51 mild COVID-19, and 160 healthy blood donors. ASCA of isotype immunoglobulin (Ig)G and IgA were detected by enzyme-linked immunosorbent assay.

RESULTS

The frequency of ASCA (IgG or IgA) was significantly higher in patients with severe COVID-19 (21.6 % vs 3.7 %, p < 10^-3) and in patients with mild COVID-19 than in the healthy controls (13.7 % vs 3.7 %, p = 0.03). ASCA-IgA was significantly more frequent in patients with severe COVID-19 than in healthy controls (15.9 % vs 0.6 %, p < 10^-3). ASCA-IgG was significantly more frequent in patients with mild COVID-19 than in healthy controls (13.7 % vs 3.1 %, p = 0.02). ASCA (IgG or IgA) were more frequent in severe than in mild COVID-19, but the difference was not statistically significant (21.6 % vs 13.7 %). ASCA-IgA was significantly more frequent in patients with severe than those with mild COVID-19 (15.9 % vs 0 %, p = 0.003). The mean ASCA-IgG and ASCA-IgA levels were significantly higher in patients with severe COVID-19 than in healthy controls (5.8 U/mL ± 11.8 vs 2.3 U/mL ± 2.8, p < 10^-3 and 9.2 U/mL ± 21.5 vs 3.4 U/mL ± 1.7, respectively, p < 10^-3). The mean ASCA-IgG levels were significantly higher in patients with mild COVID-19 than in healthy controls (6.2 U/mL ± 12.9 vs 2.3 U/mL ± 2.8, p < 10^-3). The mean ASCA-IgA levels were significantly higher in patients with severe than in those with mild COVID-19 (9.2 U/mL ± 21.5 vs 2.6 U/mL ± 1.2, p = 0.03).

CONCLUSION

ASCA was more frequent in patients with COVID-19 than in healthy controls.

Prospects for the Use of Marine Sulfated Fucose-Rich Polysaccharides in Treatment and Prevention of COVID-19 and Post-COVID-19 Syndrome

Symptoms of the new coronavirus infection that appeared in 2019 (COVID-19) range from low fever and fatigue to acute pneumonia and multiple organ failure. The clinical picture of COVID-19 is heterogeneous and involves most physiological systems; therefore, drugs with a wide spectrum of mechanism of action are required. The choice of the treatment strategy for post-COVID-19 syndrome is still a challenge to be resolved. Polysaccharides with a high fucose content derived from seaweed and marine animals can form the basis for the subsequent development of promising agents for the treatment of COVID-19 and post-COVID-19 syndrome. This class of biopolymers is characterized by a variety of biological activities, including antiviral, antithrombotic, anticoagulant, hemo-stimulating, anti-inflammatory and immune-regulatory. Low molecular weight derivatives of these polysaccharides, as well as synthetic oligosaccharides with a sufficient amount and sulfation type may be considered as the most promising compounds due to their better bioavailability, which undoubtedly increases their therapeutic potential.

Case report of actinomycotic liver abscess following COVID-19 infection

Introduction and importance

In the last few years, the novel coronavirus, named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), generated a large health care problem worldwide. Due to the immunomodulation effect of the virus the number of opportunistic infections has also increased.

Case presentation

We present the unique case of a patient who was diagnosed with an actinomycotic liver abscess after coronavirus disease 2019 (COVID-19) without the presence of any chronic disease or mucosal injury.

Clinical discussion

According to the results of the computer tomography (CT scan) and the liver biopsy, the patient was treated with antibiotics and ultrasound-guided drainage.

Conclusion

With this case we would like to draw attention to the possible occurrence of liver abscesses caused by an opportunistic pathogen following COVID-19.

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SARS-CoV-2 is an acute respiratory infection, that could result immune dysregulation.

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Immunocompromised patients have a higher risk for opportunistic infections (e.g. actinomycosis).

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Actinomycosis could result in liver abscess, which is a rare type of the liver abscesses.

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Actinomycosis followed by COVID-19 infection disease could be a post-COVID syndrome.

Gut as an Alternative Entry Route for SARS-CoV-2: Current Evidence and Uncertainties of Productive Enteric Infection in COVID-19

The gut has been proposed as a potential alternative entry route for SARS-CoV-2. This was mainly based on the high levels of SARS-CoV-2 receptor expressed in the gastrointestinal (GI) tract, the observations of GI disorders (such as diarrhea) in some COVID-19 patients and the detection of SARS-CoV-2 RNA in feces. However, the underlying mechanisms remain poorly understood. It has been proposed that SARS-CoV-2 can productively infect enterocytes, damaging the intestinal barrier and contributing to inflammatory response, which might lead to GI manifestations, including diarrhea. Here, we report a methodological approach to assess the evidence supporting the sequence of events driving SARS-CoV-2 enteric infection up to gut adverse outcomes. Exploring evidence permits to highlight knowledge gaps and current inconsistencies in the literature and to guide further research. Based on the current insights on SARS-CoV-2 intestinal infection and transmission, we then discuss the potential implication on clinical practice, including on long COVID. A better understanding of the GI implication in COVID-19 is still needed to improve disease management and could help identify innovative therapies or preventive actions targeting the GI tract.

Mechanisms Leading to Gut Dysbiosis in COVID-19: Current Evidence and Uncertainties Based on Adverse Outcome Pathways

Alteration in gut microbiota has been associated with COVID-19. However, the underlying mechanisms remain poorly understood. Here, we outlined three potential interconnected mechanistic pathways leading to gut dysbiosis as an adverse outcome following SARS-CoV-2 presence in the gastrointestinal tract. Evidence from the literature and current uncertainties are reported for each step of the different pathways. One pathway investigates evidence that intestinal infection by SARS-CoV-2 inducing intestinal inflammation alters the gut microbiota. Another pathway links the binding of viral S protein to angiotensin-converting enzyme 2 (ACE2) to the dysregulation of this receptor, essential in intestinal homeostasis-notably for amino acid metabolism-leading to gut dysbiosis. Additionally, SARS-CoV-2 could induce gut dysbiosis by infecting intestinal bacteria. Assessing current evidence within the Adverse Outcome Pathway framework justifies confidence in the proposed mechanisms to support disease management and permits the identification of inconsistencies and knowledge gaps to orient further research.

Zonulin, a marker of gut permeability, is associated with mortality in a cohort of hospitalised peruvian COVID-19 patients

Zonulin has previously been related to intestinal permeability in various inflammatory diseases, and more recently to the physiopathology of severe COVID-19 infections. We analysed serum samples from a previous study of a Peruvian cohort of hospitalised COVID-19 patients, for the quantification of zonulin by sandwich ELISA. Comparisons with clinical data, haematological and biochemical parameters and cytokine/chemokine levels were made. We found higher baseline zonulin levels in deceased patients, and zonulin was associated with fatal outcome in multivariable analyses, even after adjustment for age, gender, and obesity. There were also positive correlations between zonulin, creatinine, D-dimer values and prothrombin time, while inverse correlations were found for Sa/FiO₂ ratio and CCL5 (RANTES). Further longitudinal studies are recommended to analyse the variation of zonulin levels over time as well as their relationship with long-COVID.

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.

TGF – beta 2 enriched formula as oral nutritional supplement in patients hospitalized for COVID-19: A preliminary observational study

BACKGROUND: SARS-COV 2 turned in a global epidemic since January 2020. It is able to directly stimulate the release of proinflammatory cytokines (cytokine storm) and, affecting enterocytis, dysregulates intestinal permeability likewise Inflammatory Bowel Diseases. According to Guidelines, nutritional support in COVID-19 patients is relevant in a perspective of a fast recovery. Aim of this study is to propose in SARS-COV2 patients an early nutritional support using a polymeric - TGF-beta2 containing formula, with immunoregulatory properties specific for bowel disease, evaluating its effects on systemic inflammation and protein energy malnutrition. METHODS: COVID-19 patients hospitalized in Santa Maria Hospital of Terni and in Madonna delle Grazie Hospital of Matera (March - December 2020) were enrolled. The protocol consists in supplying 150 gr of nutritional formula powder (750 kcal/day). Values of serum prealbumin, transferrin, C-reactive protein and Lymphocyte count were collected at baseline and every week. Data were compared to a untreated sample of inpatients. RESULTS: TGF-beta2 containing formula use seems to be associated to a lower needing and longer time free from steroid therapy, increasing of prealbumin and transferrin values and overall with a better outcome in exposed patients; higher values of serum prealbumin seemed to be associated with lower CRP. It does not induce gastrointestinal discomfort or worsen gastrointestinal symptoms. CONCLUSIONS: TGF-beta2 containing formula represents a valid nutritional support in COVID-19, preventing sarcopenia associated to hypercatabolic status and modulating inflammatory response probably thanks to specific properties of its nutritional components. This is only a preliminary observation: further investigations are on-going, involving several Italian Centers.

Safety of Biologic-DMARDs in Rheumatic Musculoskeletal Disorders: A Population-Based Study over the First Two Waves of COVID-19 Outbreak

This study aims to explore disease patterns of coronavirus disease (COVID-19) in patients with rheumatic musculoskeletal disorders (RMD) treated with immunosuppressive drugs in comparison with the general population. The observational study considered a cohort of RMD patients treated with biologic drugs or small molecules from September 2019 to November 2020 in the province of Udine, Italy. Data include the assessment of both pandemic waves until the start of the vaccination, between February 2020 and April 2020 (first), and between September 2020 and November 2020 (second). COVID-19 prevalence in 1051 patients was 3.5% without significant differences compared to the general population, and the course of infection was generally benign with 2.6% mortality. A small percentage of COVID-19 positive subjects were treated with low doses of steroids (8%). The most used treatments were represented by anti-TNF agents (65%) and anti-IL17/23 agents (16%). More than two-thirds of patients reported fever, while gastro-intestinal symptoms were recorded in 27% of patients and this clinical involvement was associated with longer swab positivity. The prevalence of COVID-19 in RMD patients has been confirmed as low in both waves. The benign course of COVID-19 in our patients may be linked to the very low number of chronic corticosteroids used and the possible protective effect of anti-TNF agents, which were the main class of biologics herein employed. Gastro-intestinal symptoms might be a predictor of viral persistence in immunosuppressed patients. This finding could be useful to identify earlier COVID-19 carriers with uncommon symptoms, eventually eligible for antiviral drugs.

Zonulin and claudin-5 levels in multisystem inflammatory syndrome and SARS-CoV-2 infection in children

AIM

SARS-CoV-2 infection in children is generally asymptomatic or mild; however, it can lead to a life-threatening clinical condition, multisystem inflammatory syndrome in children (MIS-C), days or weeks after the infection. Increased intestinal permeability isa possible triggering factor at the onset of the hyperinflammation associated with MIS-C. Zonulin and claudin-5 are involved in intestinal permeability. In this study, we aimed to investigate serum zonulin and claudin-5 levels in SARS-CoV-2 infection and MIS-C disease.

METHODS

The study group consisted of children diagnosed with MIS-C or SARS-CoV-2 infection who presented to a university hospital paediatric emergency or infectious diseases departments. The control group included well patients seen at the General Pediatrics units for routine follow-up. Serum zonulin and claudin-5 levels were measured at the time of diagnosis.

RESULTS

Fifteen patients were included in the MIS-C group, 19 in the SARS-CoV-2 infection group and 21 in the control group. The mean zonulin level in the MIS-C group was significantly higher than in the control group (P < 0.001). Mean Claudin-5 levels were Psignificantly lower in the SARS-CoV-2 infection group than in the control group (P < 0.001).

CONCLUSION

These results indicate that increased intestinal permeability may be involved in the pathogenesis of SARS-CoV-2 infection and MIS-C disease. Larger clinical trials are needed to clarify the role of serum zonulin and claudin-5 on intestinal permeability in MIS-C and SARS-CoV-2 infection in children.

Resveratrol ameliorates liver fibrosis induced by nonpathogenic Staphylococcus in BALB/c mice through inhibiting its growth

Background

The altered gut microbiota is implicated in the pathogenesis of liver fibrosis. Resveratrol is a candidate for the treatment of liver fibrosis, which could ameliorate the dysregulation of gut microbiota in mice. This study aimed to clarify the role and mechanism of resveratrol in gut microbiota during liver fibrosis.

Methods

A mouse model of liver fibrosis induced by CCl₄ was conducted to assess the effect of resveratrol on liver fibrosis. The changes of gut microbiota in liver fibrotic mice after resveratrol intervention were assessed using 16S ribosomal RNA sequencing. The mechanism of the gut microbiota dysregulation in liver fibrosis was investigated by Sirius red staining, immunohistochemical assay, bacterial translocation (BT), EUB338 fluorescence in situ hybridization, immunofluorescence, trans-epithelial electrical resistance analysis and paracellular permeability analysis.

Results

Resveratrol relieved CCl₄-induced liver fibrosis. Besides, resveratrol restrained the gut microbiota Staphylococcus_lentus and Staphylococcus_xylosus in the liver fibrotic mice, and the Staphylococcus_xylosus and Staphylococcus_lentus facilitated the occurrence of BT and the cultures of them enhanced the permeability of intestine. The in vivo assay corroborated that the excessive Staphylococcus_xylosus and Staphylococcus_lentus canceled the protecting effect of resveratrol on liver fibrosis, and Staphylococcus_xylosus or Staphylococcus_lentus alone had a limited impact on the liver injury of normal mice.

Conclusion

Resveratrol ameliorated liver fibrosis by restraining the growth of Staphylococcus_xylosus and Staphylococcus_lentus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00463-y.

Persistent Overactive Cytotoxic Immune Response in a Spanish Cohort of Individuals With Long-COVID: Identification of Diagnostic Biomarkers

Long-COVID is a new emerging syndrome worldwide that is characterized by the persistence of unresolved signs and symptoms of COVID-19 more than 4 weeks after the infection and even after more than 12 weeks. The underlying mechanisms for Long-COVID are still undefined, but a sustained inflammatory response caused by the persistence of SARS-CoV-2 in organ and tissue sanctuaries or resemblance with an autoimmune disease are within the most considered hypotheses. In this study, we analyzed the usefulness of several demographic, clinical, and immunological parameters as diagnostic biomarkers of Long-COVID in one cohort of Spanish individuals who presented signs and symptoms of this syndrome after 49 weeks post-infection, in comparison with individuals who recovered completely in the first 12 weeks after the infection. We determined that individuals with Long-COVID showed significantly increased levels of functional memory cells with high antiviral cytotoxic activity such as CD8+ TEMRA cells, CD8±TCRγδ+ cells, and NK cells with CD56+CD57+NKG2C+ phenotype. The persistence of these long-lasting cytotoxic populations was supported by enhanced levels of CD4+ Tregs and the expression of the exhaustion marker PD-1 on the surface of CD3+ T lymphocytes. With the use of these immune parameters and significant clinical features such as lethargy, pleuritic chest pain, and dermatological injuries, as well as demographic factors such as female gender and O+ blood type, a Random Forest algorithm predicted the assignment of the participants in the Long-COVID group with 100% accuracy. The definition of the most accurate diagnostic biomarkers could be helpful to detect the development of Long-COVID and to improve the clinical management of these patients.

Post-infection functional gastrointestinal disorders following coronavirus disease-19: A case-control study

BACKGROUND AND AIM

Because acute infectious gastroenteritis may cause post-infection irritable bowel syndrome and functional dyspepsia and the severe acute respiratory syndrome coronavirus-2 affects gastrointestinal (GI) tract, coronavirus disease-19 (COVID-19) may cause post-infection-functional GI disorders (FGIDs). We prospectively studied the frequency and spectrum of post-infection-FGIDs among COVID-19 and historical healthy controls and the risk factors for its development.

METHODS

Two hundred eighty patients with COVID-19 and 264 historical healthy controls were followed up at 1 and 3 months using translated validated Rome Questionnaires for the development of chronic bowel dysfunction (CBD), dyspeptic symptoms, and their overlap and at 6-month for IBS, uninvestigated dyspepsia (UD) and their overlap. Psychological comorbidity was studied using Rome III Psychosocial Alarm Questionnaire.

RESULTS

At 1 and 3 months, 16 (5.7%), 16 (5.7%), 11 (3.9%), and 24 (8.6%), 6 (2.1%), 9 (3.2%) of COVID-19 patients developed CBD, dyspeptic symptoms, and their overlap, respectively; among healthy controls, none developed dyspeptic symptoms and one developed CBD at 3 months (P < 0.05). At 6 months, 15 (5.3%), 6 (2.1%), and 5 (1.8%) of the 280 COVID-19 patients developed IBS, UD, and IBS-UD overlap, respectively, and one healthy control developed IBS at 6 months (P < 0.05 for all except IBS-UD overlap). The risk factors for post-COVID-19 FGIDs at 6 months included symptoms (particularly GI), anosmia, ageusia, and presence of CBD, dyspeptic symptoms, or their overlap at 1 and 3 months and the psychological comorbidity.

CONCLUSIONS

This is the first study showing COVID-19 led to post-COVID-19 FGIDs. Post-COVID-19 FGIDs may pose a significant economic, social, and healthcare burden to the world.

COVID-19, liver dysfunction and pathophysiology: A conceptual discussion

The intra and extracellular pathways of hepatic injury by coronavirus disease 2019 (COVID-19) are still being studied. Understanding them is important to treat this viral disease and other liver and biliary tract disorders. Thus, this paper aims to present three hypotheses about liver injury caused by COVID-19: (1) The interactions between severe acute respiratory syndrome coronavirus 2 spike protein and membrane receptors in the hepatocyte; (2) The dysbiosis and “gut-liver axis” disruption in patients with serious clinical presentations of COVID-19; and (3) The inflammatory response exacerbated through the production of interleukins such as interleukin-6. However, despite these new perspectives, the pathophysiological process of liver injury caused by COVID-19 is still complex and multifactorial. Thus, understanding all these variables is a challenge to science but also the key to propose individualized and effective patient therapies.

Specific nutritional and metabolic characteristics of COVID‐19 persistent critically ill patients

Background

Little is known about metabolic and nutrition characteristics of patients with coronavirus disease 2019 (COVID‐19) and persistent critical illness. We aimed to compare those characteristics in patients with PCI and COVID‐19 and patients without COVID‐19 infection (non‐CO)—primarily, their energy balance.

Methods

This is a prospective observational study including two consecutive cohorts, defined as needing intubation for >10 days. We collected demographic data, severity scores, nutrition variables, length of stay, and mortality.

Results

Altogether, 104 patients (52 per group) were included (59 ± 14 years old [mean ± SD], 75% men) between July 2019 and May 2020. SAPSII, Nutrition Risk Screening (NRS) score, proportion of obese patients, duration of intubation (18.2 ± 11.7 days), and mortality rates were similar. Patients with COVID‐19 (vs non‐CO) had lower SOFA scores (P = 0.013) and more frequently needed prone position (P < 0.0001) and neuromuscular blockade (P < 0.0001): lengths of ICU (P = 0.03) and hospital stays were shorter (P < 0.0001). Prescribed energy targets were below those of the ICU protocol. The energy balance of patients with COVID‐19 was significantly more negative after day 10. Enteral nutrition (EN) started earlier (P < 0.0001). During the first 10 days, COVID‐19 patients received more lipid (propofol sedation) and less protein. Higher admission C‐reactive protein (P = 0.002) decreased faster (P < 0.001). Whereas intestinal function was characterized by constipation in both groups during the first 10 days, diarrhea was less common in patients with COVID‐19 thereafter.

Conclusion

Compared with non‐CO patients, COVID‐19 patients were not more obese, had lower SOFA scores, and were fed more rapidly with EN, because of a more normal gastrointestinal function possibly due to fewer non–respiratory organ failures: their energy balances were more negative after the first 10 days. Propofol sedation reduced protein delivery.

MODULATION OF INTESTINAL BARRIER FUNCTION BY GLUCOCORTICOIDS: LESSONS FROM PRECLINICAL MODELS

Glucocorticoids (GCs) are widely used drugs for their anti-inflammatory and immunosuppressant effects, but they are associated with multiple adverse effects. Despite their frequent oral administration, relatively little attention has been paid to the effects of GCs on intestinal barrier function. In this review, we present a summary of the published studies on this matter carried out in animal models and cultured cells. In cultured intestinal epithelial cells, GCs have variable effects in basal conditions and generally enhance barrier function in the presence of inflammatory cytokines such as tumor necrosis factor (TNF). In turn, in rodents and other animals, GCs have been shown to weaken barrier function, with increased permeability and lower production of IgA, which may account for some features observed in stress models. When given to animals with experimental colitis, barrier function may be debilitated or strengthened, despite a positive anti-inflammatory activity. In sepsis models, GCs have a barrier-enhancing effect. These effects are probably related to the inhibition of epithelial cell proliferation and wound healing, modulation of the microbiota and mucus production, and interference with the mucosal immune system. The available information on underlying mechanisms is described and discussed.

[Severe pseudomembranous colitis in patients with previous coronavirus infection]

OBJECTIVE

To analyze treatment outcomes in patients with severe pseudomembranous colitis and previous coronavirus infection.

MATERIAL AND METHODS

We retrospectively analyzed treatment outcomes, clinical, laboratory and histological data in convalescents of COVID-19 who admitted to the department of coloproctology for moderate-to-severe pseudomembranous colitis confirmed by endoscopic examination between 2020 and 2021.

RESULTS

There were 13 patients with moderate pseudomembranous colitis and 6 ones with severe pseudomembranous colitis. Mean period after recovery from coronavirus infection was 19 days. Endoscopy revealed whitish-yellow or gray raised plaques on colonic mucosa in all cases. Four patients with signs of peritonitis underwent emergency surgery. Three patients had perforation of caecum; one patient had perforation of sigmoid colon and widespread peritonitis. Two patients underwent urgent surgery for progressive toxic megacolon and ineffective therapy. Subtotal colectomy and ileostomy were performed in all cases. Histological examination revealed necrosis of not only superficial layer of colon mucosa typical for clostridial colitis, but also the entire thickness of mucosa, as well as submucosal and partially muscular layers in some cases. Mucosal crypt atrophy, fibrinoid effusion in muscular layer, diffuse polymorphonuclear cell infiltration and necrosis of muscular and submucosal nerve plexuses, as well as necrosis of vascular walls with deposition of hyaline-like structures characterize microcirculatory ischemic processes in the colon wall.

CONCLUSION

Severe pseudomembranous colitis associated with COVID-19 may not be associated with clostridial infection. Further analysis of possible ischemic etiology and pathogenesis of gastrointestinal lesions in COVID-19 is needed for preventive and therapeutic measures.

Postinfection Irritable Bowel Syndrome

Following acute gastroenteritis (AGE) due to bacteria, viruses, or protozoa, a subset of patients develop new onset Rome criteria positive irritable bowel syndrome (IBS), called postinfection IBS (PI-IBS). The pooled prevalence of PI-IBS following AGE was 11.5%. PI-IBS is the best natural model that suggests that a subset of patients with IBS may have an organic basis. Several factors are associated with a greater risk of development of PI-IBS following AGE including female sex, younger age, smoking, severity of AGE, abdominal pain, bleeding per rectum, treatment with antibiotics, anxiety, depression, somatization, neuroticism, recent adverse life events, hypochondriasis, extroversion, negative illness beliefs, history of stress, sleep disturbance, and family history of functional gastrointestinal disorders (FGIDs), currently called disorder of gut-brain interaction. Most patients with PI-IBS present with either diarrhea-predominant IBS or the mixed subtype of IBS, and overlap with other FGIDs, such as functional dyspepsia is common. The drugs used to treat non-constipation IBS may also be useful in PI-IBS treatment. Since randomized controlled trials on the efficacy of drugs to treat PI-IBS are rare, more studies are needed on this issue.

Phillygenin Attenuates Carbon Tetrachloride-Induced Liver Fibrosis via Modulating Inflammation and Gut Microbiota

Liver fibrosis is a chronic pathological process that various pathogenic factors lead to abnormal hyperplasia of hepatic connective tissue, and its main feature is the excessive deposition of extracellular matrix. However, there are currently no drugs approved for the treatment of liver fibrosis. Phillygenin (PHI), a lignan isolated from Forsythiae Fructus, showed potential anti-inflammatory and anti-fibrosis effects but the mechanisms remain unknown. In view of the vital role of gut microbiota in the development of liver fibrosis, this study aimed to explore whether PHI could protect intestinal epithelial barrier and attenuate liver fibrosis by maintaining the homeostasis of intestinal microbiota. Therefore, the liver fibrosis model was induced by intraperitoneal injection of olive oil containing 10% carbon tetrachloride (CCl₄) for 4 weeks in C57BL/6J mice. Histological analysis including Hematoxylin-Eosin, Masson, Sirius red, and immunohistochemistry staining were carried out to detect the histopathology and collagen deposition of mice liver tissues. The biochemical indexes related to liver function (ALT, AST, AKP, γ-GT), fibrosis (HYP, HAase, LN, PC III, IV-C) and inflammation (TNF-α, MIP-1, LPS) were determined by specific commercial assay kits. In vivo experimental results showed that PHI could improve liver histopathological injury, abnormal liver function, collagen deposition, inflammation and fibrosis caused by CCl₄. Moreover, PHI restored the intestinal epithelial barrier by promoting the expression of intestinal barrier markers, including ZO-1, Occludin and Claudin-1. More importantly, the corrective effect of PHI on the imbalance of gut microbiota was confirmed by sequencing of the 16 S rRNA gene. In particular, PHI treatment enriches the relative abundance of Lactobacillus, which is reported to alleviate inflammation and fibrosis of damaged liver. Collectively, PHI attenuates CCl₄-induced liver fibrosis partly via modulating inflammation and gut microbiota.

COVID-19 and celiac disease: A pathogenetic hypothesis for a celiac outbreak

BACKGROUND

A growing body of evidence supports the intestinal trophism of SARS-CoV-2, with ciliated cells and intestinal enterocytes being target cells because of the high expression of ACE2 and TMPRSS2. Indeed, COVID-19 promotes a "cytokine storm" in the intestinal mucosa: the resulting epithelial damage leads to increased barrier permeability, allowing the passage of gliadin in the intestinal lamina.

METHODS

Based on current literature, we hypothesize the role of COVID-19 as a potential trigger factor for celiac disease in predisposed patients.

CONCLUSIONS

Genetically predisposed patients could be more likely to develop celiac disease following SARS-CoV-2 infection, making COVID-19 a candidate culprit for a potential outbreak of celiac disease in the forthcoming future.

Immunometabolic signatures predict risk of progression to sepsis in COVID-19

Viral sepsis has been proposed as an accurate term to describe all multisystemic dysregulations and clinical findings in severe and critically ill COVID-19 patients. The adoption of this term may help the implementation of more accurate strategies of early diagnosis, prognosis, and in-hospital treatment. We accurately quantified 110 metabolites using targeted metabolomics, and 13 cytokines/chemokines in plasma samples of 121 COVID-19 patients with different levels of severity, and 37 non-COVID-19 individuals. Analyses revealed an integrated host-dependent dysregulation of inflammatory cytokines, neutrophil activation chemokines, glycolysis, mitochondrial metabolism, amino acid metabolism, polyamine synthesis, and lipid metabolism typical of sepsis processes distinctive of a mild disease. Dysregulated metabolites and cytokines/chemokines showed differential correlation patterns in mild and critically ill patients, indicating a crosstalk between metabolism and hyperinflammation. Using multivariate analysis, powerful models for diagnosis and prognosis of COVID-19 induced sepsis were generated, as well as for mortality prediction among septic patients. A metabolite panel made of kynurenine/tryptophan ratio, IL-6, LysoPC a C18:2, and phenylalanine discriminated non-COVID-19 from sepsis patients with an area under the curve (AUC (95%CI)) of 0.991 (0.986-0.995), with sensitivity of 0.978 (0.963-0.992) and specificity of 0.920 (0.890-0.949). The panel that included C10:2, IL-6, NLR, and C5 discriminated mild patients from sepsis patients with an AUC (95%CI) of 0.965 (0.952-0.977), with sensitivity of 0.993(0.984-1.000) and specificity of 0.851 (0.815-0.887). The panel with citric acid, LysoPC a C28:1, neutrophil-lymphocyte ratio (NLR) and kynurenine/tryptophan ratio discriminated severe patients from sepsis patients with an AUC (95%CI) of 0.829 (0.800-0.858), with sensitivity of 0.738 (0.695-0.781) and specificity of 0.781 (0.735-0.827). Septic patients who survived were different from those that did not survive with a model consisting of hippuric acid, along with the presence of Type II diabetes, with an AUC (95%CI) of 0.831 (0.788-0.874), with sensitivity of 0.765 (0.697-0.832) and specificity of 0.817 (0.770-0.865).

Predisposition of COVID-19 patients to secondary infections: set in stone or subject to change?

PURPOSE OF REVIEW

There likely are several predisposing factors to secondary infections in patients with Coronavirus disease 2019 (COVID-19), some of which may be preventable. The aim of this review is to explore the literature, summarize potential predisposing factors to secondary infections and their incidence. It also summarizes a variety of healthcare scenarios in which different kinds of secondary infections occur.

RECENT FINDINGS

Apart from immune dysregulation, severe resource limitations in healthcare settings have made COVID-19 units conducive to a variety of secondary infections. Long-term effect of excess antibiotic use in COVID-19 patients is yet to be studied. Very few studies have assessed secondary infections as the primary outcome measure making it difficult to know the true incidence. Mortality attributable to secondary infections in COVID-19 patients is also unclear.

SUMMARY

Incidence of secondary infections in COVID-19 patients is likely higher than what is reported in the literature. Well designed studies are needed to understand the incidence and impact of secondary infections in this patient population. Many of these may be preventable especially now, as personal protective equipment and other healthcare resources are recovering. Infection prevention and control (IPC) and antimicrobial stewardship programmes (ASP) must reassess current situation to correct any breaches that could potentially cause more harm in these already vulnerable patients as we brace for a future surge with another pandemic wave.

Association between Early Antibiotic Therapy and In-Hospital Mortality among Older Patients with SARS-CoV-2 Pneumonia

Background

It is uncertain whether antibiotic therapy should be started in SARS CoV-2 pneumonia. We aimed to investigate the association between early antibiotic therapy and the risk of in-hospital mortality in older patients.

Methods

We performed a retrospective international cohort study (ANTIBIOVID) in five COVID-19 geriatric units in France and Switzerland. Among 1,357 consecutive patients aged 75 or more hospitalised and testing positive for SARS-CoV-2, 1072 had a radiologically confirmed pneumonia, of which 914 patients were still alive and hospitalized at 48 hours. To adjust for confounders, a propensity score for treatment was created, and stabilized inverse probability of treatment weighting (SIPTW) was applied. To assess the association between early antibiotic therapy and in-hospital 30-day mortality, SIPTW-adjusted Kaplan-Meier and Cox proportional hazards regression analyses were performed.

Results

Of the 914 patients with SARS-CoV-2 pneumonia, median age of 86, 428 (46.8%) received antibiotics in the first 48 hours after diagnosis. Among these patients, 147 (34.3%) died in hospital within one month vs 118 patients (24.3%) with no early antibiotic treatment. After SIPTW, early antibiotic treatment was not significantly associated with mortality (adjusted hazard ratio, 1.23; 95% CI, 0.92-1.63; P = .160). Microbiologically confirmed superinfections occurred rarely in both groups (bacterial pneumonia: 2.5% vs 1.5%, P = .220; blood stream infection: 8.2% vs 5.2%, P = .120; Clostridioides difficile colitis: 2.4% vs 1.0%, P = .222).

Conclusions

In a large multicentre cohort of older inpatients with SARS-CoV-2 pneumonia, early antibiotic treatment did not appear to be associated with an improved prognosis.

Persistent Systemic Microbial Translocation and Intestinal Damage During Coronavirus Disease-19

Microbial translocation (MT) and intestinal damage (ID) are poorly explored in COVID-19. Aims were to assess whether alteration of gut permeability and cell integrity characterize COVID-19 patients, whether it is more pronounced in severe infections and whether it influences the development of subsequent bloodstream infection (BSI). Furthermore, we looked at the potential predictive role of TM and ID markers on Intensive Care Unit (ICU) admission and in-hospital mortality. Over March–July 2020, 45 COVID-19 patients were enrolled. Markers of MT [LPB (Lipopolysacharide Binding Protein) and EndoCab IgM] and ID [I-FABP (Intestinal Fatty Acid Binding Protein)] were evaluated at COVID-19 diagnosis and after 7 days. As a control group, age- and gender-matched healthy donors (HDs) enrolled during the same study period were included. Median age was 66 (56-71) years. Twenty-one (46.6%) were admitted to ICU and mortality was 22% (10/45). Compared to HD, a high degree of MT and ID was observed. ICU patients had higher levels of MT, but not of ID, than non-ICU ones. Likewise, patients with BSI had lower EndoCab IgM than non-BSI. Interestingly, patients with high degree of MT and low ID were likely to be admitted to ICU (AUC 0.822). Patients with COVID-19 exhibited high level of MT, especially subjects admitted to ICU. COVID-19 is associated with gut permeability.

[COVID-19 in the Intensive Care Unit: Medical, Nursing, and Physical Therapy Challenges]

COVID-19 in the Intensive Care Unit: Medical, Nursing, and Physical Therapy Challenges Abstract. The treatment of patients with COVID-19 is a big challenge for intensive care units: substantial additional staff and material is needed to treat the surge of patients admitted in short time. Treatment is difficult as many patients present with multiple organ failure, including acute respiratory distress syndrome (ARDS). Mostly, oxygenation is substantially impaired and compliance low, and many patients need prone positioning. This article deals with the difficulties during the first surge of patients with COVID-19. The suffering of the relatives who were not allowed to visit must also be considered.

Endothelial Senescence and Chronic Fatigue Syndrome, a COVID-19 Based Hypothesis

Myalgic encephalomyelitis/chronic fatigue syndrome is a serious illness of unknown etiology, characterized by debilitating exhaustion, memory impairment, pain and sleep abnormalities. Viral infections are believed to initiate the pathogenesis of this syndrome although the definite proof remains elusive. With the unfolding of COVID-19 pandemic, the interest in this condition has resurfaced as excessive tiredness, a major complaint of patients infected with the SARS-CoV-2 virus, often lingers for a long time, resulting in disability, and poor life quality. In a previous article, we hypothesized that COVID-19-upregulated angiotensin II triggered premature endothelial cell senescence, disrupting the intestinal and blood brain barriers. Here, we hypothesize further that post-viral sequelae, including myalgic encephalomyelitis/chronic fatigue syndrome, are promoted by the gut microbes or toxin translocation from the gastrointestinal tract into other tissues, including the brain. This model is supported by the SARS-CoV-2 interaction with host proteins and bacterial lipopolysaccharide. Conversely, targeting microbial translocation and cellular senescence may ameliorate the symptoms of this disabling illness.

A Dual-Route Perspective of SARS-CoV-2 Infection: Lung- vs. Gut-specific Effects of ACE-2 Deficiency

SARS-CoV-2, primarily considered a respiratory virus, is increasingly recognized as having gastrointestinal aspects based on its presence in the gastrointestinal (GI) tract and feces. SARS-CoV-2 uses as a receptor angiotensin-converting enzyme 2 (ACE-2), a critical member of the renin-angiotensin-aldosterone system (RAAS) involved in the regulation of blood pressure and fluid system. In addition to the systemic endocrine functions, RAAS components are also involved in intracrine and organ-specific local functions. The angiotensin-converting enzyme 2 (ACE-2) is a key component of RAAS and a receptor for SARS-CoV-2. It is expressed in many tissues with gastrointestinal (GI) tract ACE-2 levels far exceeding those in the respiratory tract. SARS-CoV-2 binding to its receptor results in a deficiency of ACE-2 activity in endocrine, intracrine, and local lung and GI tract ACE-2. The local ACE-2 has different organ-specific functions, including hypertension-independent activities; dysregulations of these functions may contribute to multiorgan COVID-19 pathology, its severity, long-term effects, and mortality. We review supporting evidence from this standpoint. Notably, COVID-19 comorbidities involving hypertension, obesity, heart disease, kidney disease, and diabetes are associated with gastrointestinal problems and display ACE-2 deficits. While RAAS inhibitors target both endocrine and intracrine ACE-2 activity, the deficit of the local ACE-2 activity in the lungs and more so in the gut have not been targeted. Consequently, the therapeutic approach to COVID-19 should be carefully reconsidered. Ongoing clinical trials testing oral probiotic bound ACE-2 delivery are promising.