Increased intestinal permeability is associated with the development of multiple organ dysfunction syndrome in critically ill ICU patients

Mixed Shock Complicating Cardiogenic Shock: Frequency, Predictors, and Clinical Outcomes

BACKGROUND

Patients presenting with cardiogenic shock (CS) are at risk of developing mixed shock (MS), characterized by distributive-inflammatory phenotype. However, no objective definition exists for this clinical entity.

METHODS

We assessed the frequency, predictors, and prognostic relevance of MS complicating CS, based on a newly proposed objective definition. MS complicating CS was defined as an objective shock state secondary to both an ongoing cardiogenic cause and a distributive-inflammatory phenotype arising at least 12 hours after the initial CS diagnosis, as substantiated by predefined longitudinal changes in hemodynamics, clinical, and laboratory parameters.

RESULTS

Among 213 consecutive patients admitted at 2 cardiac intensive care units with CS, 13 with inflammatory-distributive features at initial presentation were excluded, leading to a cohort of 200 patients hospitalized with pure CS (67±13 years, 96% Society of Cardiovascular Angiography and Interventions CS stage class C or higher). MS complicating CS occurred in 24.5% after 120 (29-216) hours from CS diagnosis. Lower systolic arterial pressure (P=0.043), hepatic injury (P=0.049), and suspected/definite infection (P=0.013) at CS diagnosis were independent predictors of MS development. In-hospital mortality (53.1% versus 27.8%; P=0.002) and hospital stay (21 [13-48] versus 17 [9-27] days; P=0.018) were higher in the MS cohort. At logistic multivariable analysis, MS diagnosis (odds ratio [OR], 3.00 [95% CI, 1.39-6.63]; Padj=0.006), age (OR, 1.06 [95% CI, 1.03-1.10] years; Padj<0.001), admission systolic arterial pressure <100 mm Hg (OR, 2.41 [95% CI, 1.19-4.98]; Padj=0.016), and admission serum creatinine (OR, 1.61 [95% CI, 1.19-2.26]; Padj=0.003) conferred higher odds of in-hospital death, while early temporary mechanical circulatory support was associated with lower in-hospital death (OR, 0.36 [95% CI, 0.17-0.75]; Padj=0.008).

CONCLUSIONS

MS complicating CS, objectively defined leveraging on longitudinal changes in distributive and inflammatory features, occurs in one-fourth of patients with CS, is predicted by markers of CS severity and inflammation at CS diagnosis, and portends higher hospital mortality.

Prognostic Value of Acute Gastrointestinal Injury Combined with Disease Severity Scores in Critically Ill Patients

Background

Critically ill patients are at high risk of multiple organ failure syndrome (MODS) and gastrointestinal (GI) injury and dysfunction, which are associated with increased mortality rates. The acute gastrointestinal injury (AGI) scale has shown promise in assessing GI dysfunction. However, the combined utility of AGI with established disease severity scores remains unclear. This study aimed to investigate the performance of AGI in conjunction with modified nutritional risk in critically ill (mNUTRIC), sequential organ failure assessment (SOFA), and acute physiology and chronic health evaluation II (APACHE II) scores for predicting mortality in critically ill patients.

Materials and methods

A retrospective cross-sectional study was conducted in the intensive care unit (ICU) from May 2021 to December 2021. Demographic and clinical data were collected, including AGI grade, mNUTRIC score, SOFA score, APACHE II score, and mortality.

Results

Among 93 critically ill patients, AGI was observed in 47.3% of cases, and the in-hospital mortality rate was 30.1%. The area under the curve (AUC) for AGI in predicting in-hospital mortality was 0.67 [95% confidence interval (CI), 0.56, 0.79; p = 0.008], similar to the AUCs of SOFA, APACHE II, and mNUTRIC scores. The combination of AGI with mNUTRIC, APACHE II, or SOFA scores improved the predictive performance compared with AGI alone.

Conclusion

The AGI grade, in conjunction with disease severity scores, such as mNUTRIC, SOFA, and APACHE II scores, shows promise in predicting mortality in critically ill patients. Integrating AGI into evaluating critically ill patients can enhance prognostic accuracy.

How to cite this article

Hai PD, Tot NH, Thao LT, Khoa Q, Thien DH. Prognostic Value of Acute Gastrointestinal Injury Combined with Disease Severity Scores in Critically Ill Patients. Indian J Crit Care Med 2024;28(6):575-580.

Clinical practice guidelines for nutritional assessment and monitoring of adult ICU patients in China

The Chinese Society of Critical Care Medicine (CSCCM) has developed clinical practice guidelines for nutrition assessment and monitoring for patients in adult intensive care units (ICUs) in China. This guideline focuses on nutrition evaluation and metabolic monitoring to achieve optimal and personalized nutrition therapy for critically ill patients. This guideline was developed by experts in critical care medicine and evidence-based medicine methodology and was developed after a thorough review of the system and a summary of relevant trials or studies published from 2000 to July 2023. A total of 18 recommendations were formed and consensus was reached through discussions and reviews by expert groups in critical care medicine, parenteral and enteral nutrition, and surgery. The recommendations are based on currently available evidence and cover several key fields, including screening and assessment, evaluation and assessment of enteral feeding intolerance, metabolic and nutritional measurement and monitoring during nutrition therapy, and organ function evaluation related to nutrition supply. Each question was analyzed according to the Population, Intervention, Comparison, and Outcome (PICO) principle. In addition, interpretations were provided for four questions that did not reach a consensus but may have potential clinical and research value. The plan is to update this nutrition assessment and monitoring guideline using the international guideline update method within 3-5 years.

Plasma citrulline concentration and plasma LPS detection among critically ill patients a prospective observational study

PURPOSE

Gut can be a source of sepsis but sepsis itself can induce gut dysfunction. We aimed to study whether plasma citrulline, a marker of enterocyte mass, was correlated with plasma lipopolysaccharide, a potential marker of bacterial translocation among critically ill patients.

MATERIALS AND METHODS

Critically ill patients admitted to the ICU. Plasma citrulline and plasma LPS concentration and activity were measured at ICU admission. Patients were compared according to the presence of sepsis at ICU admission.

RESULTS

109 critically ill patients, with SOFA score 8 [6-12], were prospectively included. Sixty six patients (61%) had sepsis at ICU admission. There was no correlation between plasma citrulline concentration and plasma LPS concentration or activity. However, sepsis at ICU admission was associated with a lower plasma citrulline concentration (13.4 μmol.L-1 vs 21.3 μmol.L-1, p = 0.02). Plasma LPS activity was significantly higher among patients with abdominal sepsis compared to patients with extra-abdominal sepsis (1.04 EU/mL vs 0.63, p = 0.01).

CONCLUSIONS

Plasma citrulline is not associated with the level of plasma LPS but is strongly decreased among septic patients. Detection of LPS is ubiquitous among critically ill patients but abdominal sepsis is associated with increased plasma LPS activity compared to extra-abdominal sepsis.

Pathogenesis and therapeutic opportunities of gut microbiome dysbiosis in critical illness

For many years, it has been hypothesized that pathological changes to the gut microbiome in critical illness is a driver of infections, organ dysfunction, and other adverse outcomes in the intensive care unit (ICU). The advent of contemporary microbiome methodologies and multi-omics tools have allowed researchers to test this hypothesis by dissecting host-microbe interactions in the gut to better define its contribution to critical illness pathogenesis. Observational studies of patients in ICUs have revealed that gut microbial communities are profoundly altered in critical illness, characterized by markedly reduced alpha diversity, loss of commensal taxa, and expansion of potential pathogens. These key features of ICU gut dysbiosis have been associated with adverse outcomes including life-threatening hospital-acquired (nosocomial) infections. Current research strives to define cellular and molecular mechanisms connecting gut dysbiosis with infections and other outcomes, and to identify opportunities for therapeutic modulation of host-microbe interactions. This review synthesizes evidence from studies of critically ill patients that have informed our understanding of intestinal dysbiosis in the ICU, mechanisms linking dysbiosis to infections and other adverse outcomes, as well as clinical trials of microbiota-modifying therapies. Additionally, we discuss novel avenues for precision microbial therapeutics to combat nosocomial infections and other life-threatening complications of critical illness.

Prediction of mechanical ventilation outcome by early abdominal-visceral-blood-flow-and-function score in critically ill patients after cardiopulmonary bypass in the ICU: A prospective observational study

Background

Abdominal organs are important organs that sense and respond to ischemia and hypoxia, but there are few evaluation methods.We use ultrasonography to evaluate abdominal organ function and blood flow in patients with mechanical ventilation (MV) after cardiopulmonary bypass and to obtain a semiquantitative score for abdominal organ function and blood flow.

Methods

Patients with cardiopulmonary bypass in the Critical Care Department of Peking Union Medical College Hospital in China from March to July 2021 were enrolled in this prospective observational study. The correlation of the abdominal-visceral-blood-flow-and-function score (AVBFS) with the duration of MV, number of days spent in the intensive care unit (ICU), acute physiology and chronic health evaluation II (APACHE-II), sequential organ failure assessment (SOFA), lactate, epinephrine, and norepinephrine use was analyzed, and the results were used to assess the predictive value of the receiver operating characteristic curve (ROC) regression analysis score for the duration of MV.

Results

Of the 92 patients who underwent cardiopulmonary bypass, 41 were finally included. The AVBFS were significantly correlated with the duration of MV, number of days spent in the ICU, APACHE-II score, SOFA score, and norepinephrine use time. The AVBFS in a group of patients using ventilators ≥36 h were significantly higher than those obtained for a group of patients using ventilators <36 h (P <0.05). The evaluation results for the AVBFS at 0-12 h after ICU admission were as follows: area under the ROC curve (AUC)=0.876 (95% confidence interval [CI]: 0.767 to 0.984), cut-off value=2.5, specificity=0.842, and sensitivity=0.773.

Conclusions

Abdominal visceral organ function and blood perfusion can be used to evaluate gastrointestinal function. It is related to early and late extubation after cardiac surgery.

Traumatic brain injury, abnormal growth hormone secretion, and gut dysbiosis

The gut microbiome has been implicated in a variety of neuropathologies with recent data suggesting direct effects of the microbiome on host metabolism, hormonal regulation, and pathophysiology. Studies have shown that gut bacteria impact host growth, partially mediated through the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis. However, no study to date has examined the specific role of GH on the fecal microbiome (FMB) or the changes in this relationship following a traumatic brain injury (TBI). Current literature has demonstrated that TBI can lead to either temporary or sustained abnormal GH secretion (aGHS). More recent literature has suggested that gut dysbiosis may contribute to aGHS leading to long-term sequelae now known as brain injury associated fatigue and cognition (BIAFAC). The aGHS observed in some TBI patients presents with a symptom complex including profound fatigue and cognitive dysfunction that improves significantly with exogenous recombinant human GH treatment. Notably, GH treatment is not curative as fatigue and cognitive decline typically recur upon treatment cessation, indicating the need for additional studies to address the underlying mechanistic cause.

A foundational approach to culture and analyze malnourished organoids

The gastrointestinal (GI) epithelium plays a major role in nutrient absorption, barrier formation, and innate immunity. The development of organoid-based methodology has significantly impacted the study of the GI epithelium, particularly in the fields of mucosal biology, immunity, and host-microbe interactions. Various effects on the GI epithelium, such as genetics and nutrition, impact patients and alter disease states. Thus, incorporating these effects into organoid-based models will facilitate a better understanding of disease progression and offer opportunities to evaluate therapeutic candidates. One condition that has a significant effect on the GI epithelium is malnutrition, and studying the mechanistic impacts of malnutrition would enhance our understanding of several pathologies. Therefore, the goal of this study was to begin to develop methodology to generate viable malnourished organoids with accessible techniques and resources that can be used for a wide array of mechanistic studies. By selectively limiting distinct macronutrient components of organoid media, we were able to successfully culture and evaluate malnourished organoids. Genetic and protein-based analyses were used to validate the approach and confirm the presence of known biomarkers of malnutrition. Additionally, as proof-of-concept, we utilized malnourished organoid-derived monolayers to evaluate the effect of malnourishment on barrier formation and the ability of the bacterial pathogen Shigella flexneri to infect the GI epithelium. This work serves as the basis for new and exciting techniques to alter the nutritional state of organoids and investigate the related impacts on the GI epithelium.

Tracking gut microbiome and bloodstream infection in critically ill adults

BACKGROUND

The gut microbiome is believed to contribute to bloodstream infection (BSI) via translocation of dominant gut bacteria in vulnerable patient populations. However, conclusively linking gut and blood organisms requires stringent approaches to establish strain-level identity.

METHODS

We enrolled a convenience cohort of critically ill patients and investigated 86 bloodstream infection episodes that occurred in 57 patients. Shotgun metagenomic sequencing was used to define constituents of their gut microbiomes, and whole genome sequencing and assembly was done on 23 unique bloodstream isolates that were available from 21 patients. Whole genome sequences were downloaded from public databases and used to establish sequence-identity distribution and define thresholds for unrelated genomes of BSI species. Gut microbiome reads were then aligned to whole genome sequences of the cognate bloodstream isolate and unrelated database isolates to assess identity.

RESULTS

Gut microbiome constituents matching the bloodstream infection species were present in half of BSI episodes, and represented >30% relative abundance of gut sequences in 10% of episodes. Among the 23 unique bloodstream organisms that were available for whole genome sequencing, 14 were present in gut at the species level. Sequence alignment applying defined thresholds for identity revealed that 6 met criteria for identical strains in blood and gut, but 8 did not. Sequence identity between BSI isolates and gut microbiome reads was more likely when the species was present at higher relative abundance in gut.

CONCLUSION

In assessing potential gut source for BSI, stringent sequence-based approaches are essential to determine if organisms responsible for BSI are identical to those in gut: of 14 evaluable patients in which the same species was present in both sites, they were identical in 6/14, but were non-identical in 8/14 and thus inconsistent with gut source. This report demonstrates application of sequencing as a key tool to investigate infection tracking within patients.

Biomarkers and Functional Assays of Epithelial Barrier Disruption and Gastrointestinal Dysmotility in Critical Illness-A Narrative Review

Enteral nutrition in critically ill children has been associated with improved clinical outcomes. Gastrointestinal dysfunction often impedes the timely initiation and advancement of enteral nutrition and can contribute to immune dysregulation and systemic inflammation. Therefore, assessing gastrointestinal function, at a cellular and functional level, is important to provide optimal enteral nutrition therapy and reduce the gastrointestinal tract's contribution to the inflammatory cascade of critical illness. In this narrative review, we present an overview of biomarker and functional assays for gastrointestinal dysfunction, including epithelial barrier disruption and gastrointestinal dysmotility, that have been considered for critically ill patients.

Early oral nutritional supplement improves COVID-19 outcomes among hospitalized older patients during the Omicron wave

OBJECTIVES

The effect of and optimal timing for initiating an oral nutritional supplement(ONS) in hospitalized older patients with the Omicron variant infection remain unclear. The aim of this study was to explore the associations between the ONS and clinical outcomes.

METHODS

This study used a retrospective cohort design as primary analysis and a case-control design as sensitivity analysis. We collected data from patients with confirmed coronavirus disease 2019 (COVID-19) between April 2022 and June 2022 at Shanghai Fourth People's Hospital, one of the designated medical centers for COVID-19 in Shanghai, China. Patients were identified as ONS users or non-ONS users, with the former defined as early ONS (ONS initiated within 48 h from hospital admission), and late ONS (ONS initiated after 48 h) users.

RESULTS

The study included 1181 hospitalized patients ≥60 y of age. The mean age of the cohort was 78 y, and most patients were women (57.7%). Mortalities after propensity-score matching were 1.2% and 4.3% in the ONS group and non-ONS groups, respectively (P = 0.032). Subgroup analysis results showed that median (IQR) hospital length of stay and the median (IQR) length from symptom onset to viral clearance were shorter for the early ONS than for the late ONS group (9 [6-13] d versus 14 [11 -18] d; P < 0.001, and 11 [8-17] d versus 17 [13-22] d; P < 0.001, respectively). The findings from the case-control analysis supported those from the primary analysis.

CONCLUSIONS

Early ONS might have significantly lowered risk for in-hospital death, as well as reduce hospital length of stay and days of viral clearance in older patients with COVID-19 during the Omicron wave.

Paracellular permeability and tight junction regulation in gut health and disease

Epithelial tight junctions define the paracellular permeability of the intestinal barrier. Molecules can cross the tight junctions via two distinct size-selective and charge-selective paracellular pathways: the pore pathway and the leak pathway. These can be distinguished by their selectivities and differential regulation by immune cells. However, permeability increases measured in most studies are secondary to epithelial damage, which allows non-selective flux via the unrestricted pathway. Restoration of increased unrestricted pathway permeability requires mucosal healing. By contrast, tight junction barrier loss can be reversed by targeted interventions. Specific approaches are needed to restore pore pathway or leak pathway permeability increases. Recent studies have used preclinical disease models to demonstrate the potential of pore pathway or leak pathway barrier restoration in disease. In this Review, we focus on the two paracellular flux pathways that are dependent on the tight junction. We discuss the latest evidence that highlights tight junction components, structures and regulatory mechanisms, their impact on gut health and disease, and opportunities for therapeutic intervention.

Application background and mechanism of short-chain fatty acids in sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a frequent brain dysfunction found in sepsis patients, manifesting as delirium, cognitive impairment, and abnormal behaviors. The gut microbiome and short-chain fatty acids (SCFAs) are particularly associated with neuroinflammation in patients with SAE, thus noticeably attracting scholars’ attention. The association of brain function with the gut-microbiota-brain axis was frequently reported. Although the occurrence, development, and therapeutic strategies of SAE have been extensively studied, SAE remains a critical factor in determining the long-term prognosis of sepsis and is typically associated with high mortality. This review concentrated on the interaction of SCFAs with microglia in the central nervous system and discussed the anti-inflammatory and immunomodulatory effects of SCFAs by binding to free fatty acid receptors or acting as histone deacetylase inhibitors. Finally, the prospects of dietary intervention using SCFAs as dietary nutrients in improving the prognosis of SAE were reviewed.

Plasma riboflavin fluorescence as a diagnostic marker of mesenteric ischemia-reperfusion injury in rats

Due to the delayed and vague symptoms, it is difficult to early diagnose mesenteric ischemia injuries in the dynamics of acute illness, leading to a 60-80 % mortality rate. Here, we found plasma fluorescence spectra can rapidly assess the severity of mesenteric ischemia injury in animal models. Ischemia-reperfusion damage of the intestine leads to multiple times increase in NADH, flavins, and porphyrin auto-fluorescence of blood. The fluorescence intensity ratio between blue-fluorophores and flavins can reflect the occurrence of shock. Using liquid chromatography and mass spectroscopy, we confirm that riboflavin is primarily responsible for the increased flavin fluorescence. Since humans absorb riboflavin from the intestine, its increase in plasma may indicate intestinal mucosa injury. Our work suggests a self-calibrated and reagent-free approach to identifying the emergence of fatal mesenteric ischemia in emergency departments or intensive care units.

The role of serum circulating microbial toxins in severity and cytokine storm of COVID positive patients

The emergence of Coronavirus disease 2019 (Covid-19) is a global problem nowadays, causing health difficulty with increasing mortality rates, which doesn't have a verified treatment. SARS-CoV-2 infection has various pathological and epidemiological characteristics, one of them is increased amounts of cytokine production, which in order activate an abnormal unrestricted response called "cytokine storm". This event contributes to severe acute respiratory distress syndrome (ARDS), which results in respiratory failure and pneumonia and is the great cause of death associated with Covid-19. Endotoxemia and the release of bacterial lipopolysaccharides (endotoxins) from the lumen into the bloodstream enhance proinflammatory cytokines. SARS-CoV-2 can straightly interplay with endotoxins via its S protein, leading to the extremely elevating release of cytokines and consequently increase the harshness of Covid-19. In this review, we will discuss the possible role of viral-bacterial interaction that occurs through the transfer of bacterial products such as lipopolysaccharide (LPS) from the intestine into the bloodstream, exacerbating the severity of Covid-19 and cytokine storms.

Activation of GPR81 aggravated intestinal ischemia/reperfusion injury-induced acute lung injury via HMGB1-mediated neutrophil extracellular traps formation

INTRODUCTION

Intestinal ischemia/reperfusion (II/R) injury is a life-threatening situation accompanied by severe organ injury, especially acute lung injury (ALI). A great body of evidence indicates that II/R injury is usually associated with hyperlactatemia. G-protein-coupled receptor 81 (GPR81), a receptor of lactate, has been recognized as a regulatory factor in inflammation, but whether it was involved in II/R injury-induced ALI is still unknown.

METHODS

To establish the II/R injury model, the superior mesenteric artery of the mice was occluded gently by a microvascular clamp for 45 min to elicit intestinal ischemia and then a 90-min reperfusion was performed. Broncho-alveolar lavage fluid (BALF) and lung tissues were obtained to evaluate the lung injury after II/R. The pulmonary histopathological alteration was evaluated by H&E staining. The concentration of proteins, the number of infiltrated cells, and the level of IL-6 were measured in BALF. The formation of neutrophil extracellular traps (NETs) was evaluated by the level of double-stranded DNA (dsDNA) and myeloperoxidase- double-stranded DNA (MPO-dsDNA) complex in BALF, and the content of citrullinated histone H3 (Cit-H3) in lung tissue. The level of HMGB1 in the BALF and plasma was measured by enzyme linked immunosorbent assay (ELISA).

RESULTS

Administration of the GPR81 agonist 3,5-dihydroxybenzoic acid (DHBA) aggravated II/R injury-induced lung histological abnormalities, upregulated the concentration of proteins, the number of infiltrated cells, and the level of IL-6 in BALF. In addition, DHBA treatment increased the level of dsDNA and MPO-dsDNA complex in BALF, and promoted the elevation of Cit-H3 in lung tissue and the release of HMGB1 in BALF and plasma.

CONCLUSION

After induction of ALI by II/R, the administration of DHBA aggravated ALI through NETs formation in the lung.

Early versus delayed enteral nutrition in mechanically ventilated patients with circulatory shock: a nested cohort analysis of an international multicenter, pragmatic clinical trial

Introduction

Real-world evidence on the timing and efficacy of enteral nutrition (EN) practices in intensive care unit (ICU) patients with circulatory shock is limited. We hypothesized early EN (EEN), as compared to delayed EN (DEN), is associated with improved clinical outcomes in mechanically ventilated (MV) patients with circulatory shock.

Methods

We analyzed a dataset from an international, multicenter, pragmatic randomized clinical trial (RCT) evaluating protein dose in ICU patients. Data were collected from ICU admission, and EEN was defined as initiating < 48 h from ICU admission and DEN > 48 h. We identified MV patients in circulatory shock to evaluate the association between the timing of EN initiation and clinical outcomes. The regression analysis model controlled for age, mNUTRIC score, APACHE II score, sepsis, and Site.

Results

We included 626 patients, from 52 ICUs in 14 countries. Median age was 60 years [18–93], 55% had septic shock, 99% received norepinephrine alone, 91% received EN alone, and 50.3% were randomized to a usual protein dose. Forty-two percent of EEN patients had persistent organ dysfunction syndrome plus death at day 28, compared to 53% in the DEN group (p = 0.04). EEN was associated with more ICU-free days (9.3 ± 9.2 vs. 5.7 ± 7.9, p = 0.0002), more days alive and free of vasopressors (7.1 ± 3.1 vs. 6.3 ± 3.2, p = 0.007), and shorter duration of MV among survivors (9.8 ± 10.9 vs. 13.8 ± 14.5, p = 0.0002). This trend was no longer observed in the adjusted analysis. There were no differences in ICU/60-day mortality or feeding intolerance rates between groups.

Conclusion

In MV patients with circulatory shock, EEN, as compared to DEN, was associated with improved clinical outcomes, but no longer when adjusting for illness severity. RCTs comparing the efficacy of EEN to DEN in MV patients with circulatory shock are warranted.

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.

Tackling recalcitrant Pseudomonas aeruginosa infections in critical illness via anti-virulence monotherapy

Intestinal barrier derangement allows intestinal bacteria and their products to translocate to the systemic circulation. Pseudomonas aeruginosa (PA) superimposed infection in critically ill patients increases gut permeability and leads to gut-driven sepsis. PA infections are challenging due to multi-drug resistance (MDR), biofilms, and/or antibiotic tolerance. Inhibition of the quorum-sensing transcriptional regulator MvfR(PqsR) is a desirable anti-PA anti-virulence strategy as MvfR controls multiple acute and chronic virulence functions. Here we show that MvfR promotes intestinal permeability and report potent anti-MvfR compounds, the N-Aryl Malonamides (NAMs), resulting from extensive structure-activity-relationship studies and thorough assessment of the inhibition of MvfR-controlled virulence functions. This class of anti-virulence non-native ligand-based agents has a half-maximal inhibitory concentration in the nanomolar range and strong target engagement. Using a NAM lead in monotherapy protects murine intestinal barrier function, abolishes MvfR-regulated small molecules, ameliorates bacterial dissemination, and lowers inflammatory cytokines. This study demonstrates the importance of MvfR in PA-driven intestinal permeability. It underscores the utility of anti-MvfR agents in maintaining gut mucosal integrity, which should be part of any successful strategy to prevent/treat PA infections and associated gut-derived sepsis in critical illness settings. NAMs provide for the development of crucial preventive/therapeutic monotherapy options against untreatable MDR PA infections.

Pseudomonas aeruginosa infections are increasingly difficult to treat due to the development of antimicrobial resistance. Here, the authors describe the synthesis, characterisation and efficacy of a quorum sensing inhibitor.

Stress ulcer prophylaxis for critically ill children: routine use needs to be re-examined

INTRODUCTION

Stress ulcer prophylaxis (SUP) is commonly used in Paediatric Intensive Care Units (PICUs). However, strong evidence for this practice is lacking and there is a dire need for paediatric randomized controlled trials (RCTs). Our aim was to assess the usefulness of SUP with omeprazole in critically ill children.

PATIENTS AND METHODS

We conducted a randomized, controlled open-label trial, including 144 children admitted into a PICU with a paediatric Sequential Organ Failure Assessment (pSOFA) score of less than 16. We randomly allocated patients to SUP with omeprazole or no SUP. The primary outcome was development of upper gastrointestinal bleeding or nosocomial infection.

RESULTS

The incidence of gastrointestinal bleeding was 27.1%, but clinically significant bleeding developed in only 5.6% of patients. We did not find a significant difference in the incidence of bleeding between the prophylaxis and control groups (27.8% vs 26.4%; P = .85). We also did not find a significant difference between the groups in the incidence of ventilator-associated pneumonia (VAP) (9.6% vs 8.3%; P = .77). The incidence of central line-associated bloodstream infection (CLABSI) was higher in the prophylaxis group compared to the control group (30.6% vs 12.5%; P = .014). None of the patients developed Clostridium difficile-associated diarrhoea. We did not find significant differences in mortality, length of PICU stay or duration of mechanical ventilation. Mechanical ventilation was an independent predictor of bleeding (OR, 6.4; 95%CI, 2.73-14.9).

CONCLUSION

In PICU patients with mild to moderate organ dysfunction, omeprazole does not seem to be useful for prevention of gastrointestinal bleeding while at the same time increasing the risk of CLABSI. Thus, we recommend restricting SUP to mechanically ventilated children.

Acute gastrointestinal injury in critically ill children: Impact on clinical outcome

AIM

To estimate acute gastrointestinal injury (AGI) in critically ill children and association of its severity with mortality.

METHODS

In a prospective cohort study, critically ill children (1 month-18 years) were enrolled. Gastrointestinal symptoms over the first week of admission were classified into AGI grades 1 through 4, using a paediatric adaptation of European Society of Intensive Care Medicine AGI definitions. Performance of AGI grades in predicting 28-day mortality was evaluated.

RESULTS

Of 151 children enrolled, 71 (47%, 95% confidence interval (CI): 38.9-55.3%) developed AGI, with AGI grades 1, 2, 3 and 4 in 22.5%, 15.9%, 6.6% and 2%, respectively. The 28-day mortality progressively increased with AGI grade 0 (15%), 1 (35%), 2 (50%), 3 (70%), through 4 (100%), P < 0.001. Association of AGI grades with 28-day mortality was significant even after adjustment for disease severity, age and nutritional status (odds ratio (OR) = 2.152, 95% CI: 1.455, 3.184). Among AGI grades, and paediatric logistic organ dysfunction-2 score components, cardiovascular (OR = 1.525, 95% CI: 1.142, 2.037) and haematological (OR = 1.719, 95% CI: 1.067, 2.772) components of paediatric logistic organ dysfunction-2 score and AGI grades (OR = 1.565, 95% CI: 1.001, 2.449) showed significant association with 28-day mortality.

CONCLUSIONS

Nearly half of the critically ill children developed AGI. AGI grades were independently associated with increased mortality, and mortality progressively increased with AGI grade.

Gut barrier disruption and chronic disease

The intestinal barrier protects the host against gut microbes, food antigens, and toxins present in the gastrointestinal tract. However, gut barrier integrity can be affected by intrinsic and extrinsic factors, including genetic predisposition, the Western diet, antibiotics, alcohol, circadian rhythm disruption, psychological stress, and aging. Chronic disruption of the gut barrier can lead to translocation of microbial components into the body, producing systemic, low-grade inflammation. While the association between gut barrier integrity and inflammation in intestinal diseases is well established, we review here recent studies indicating that the gut barrier and microbiota dysbiosis may contribute to the development of metabolic, autoimmune, and aging-related disorders. Emerging interventions to improve gut barrier integrity and microbiota composition are also described.

Comparison of Intestinal Microbiota Between Healthy and MMVD Chihuahuas Using 16S rRNA Gene Amplicon Sequencing

Myxomatous mitral valve disease (MMVD) is the most common cause of congestive heart failure in dogs, and although complications of MMVD to the lungs and kidneys have been identified, complications to the gut are less well understood. The intestinal microbiota is an important factor in the gut, and although the association between heart disease and the intestinal microbiota has been shown in human medicine, it is unknown in dogs. The study aimed to evaluate the relationship between MMVD and gut microbiota. A total of 69 healthy Chihuahuas and Chihuahuas with MMVD were evaluated for cardiac health by echocardiography and chest radiography and grouped according to ACVIM guidelines. Fecal samples were collected from all cases and 16S rRNA sequencing was used to reveal the intestinal microbiota. There were significant differences in LA/Ao, LVIDd, E vel, VHS, and VLAS with the severity of ACVIM. On the other hand, there were no significant differences in the diversity and composition of gut microbiota among the groups. The present study did not identify the effects of MMVD on the gut microbiota.

Perspective: Drawing on Findings From Critical Illness to Explain Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

We propose an initial explanation for how myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) could originate and perpetuate by drawing on findings from critical illness research. Specifically, we combine emerging findings regarding (a) hypoperfusion and endotheliopathy, and (b) intestinal injury in these illnesses with our previously published hypothesis about the role of (c) pituitary suppression, and (d) low thyroid hormone function associated with redox imbalance in ME/CFS. Moreover, we describe interlinkages between these pathophysiological mechanisms as well as “vicious cycles” involving cytokines and inflammation that may contribute to explain the chronic nature of these illnesses. This paper summarizes and expands on our previous publications about the relevance of findings from critical illness for ME/CFS. New knowledge on diagnostics, prognostics and treatment strategies could be gained through active collaboration between critical illness and ME/CFS researchers, which could lead to improved outcomes for both conditions.

Intestinal Complication With Myxomatous Mitral Valve Diseases in Chihuahuas

The effects of cardiac disease on the intestine have been reported in humans but not in dogs. We investigated the effects of myxomatous mitral valve disease (MMVD), which is capable of causing congestion and tissue hypoperfusion, on the intestine in Chihuahuas, a breed frequently encountered in clinical practice as the preferred breed for MMVD. In this study, 69 Chihuahuas were divided into four groups based on echocardiography and chest radiography: 19 healthy Chihuahuas (H) and 50 Chihuahuas with MMVD classified according to the ACVIM consensus (stage B1, B2, C/D). In all the cases, serum intestinal fatty acid-binding protein (I-FABP) and D/L-lactate concentrations, markers of intestinal mucosal injury, were measured. I-FABP was significantly higher in stage C/D Chihuahuas than in other groups (p < 0.05), and stage B2 was significantly higher than H (p < 0.05). D-lactate was significantly increased in stages B2 and C/D compared to H and stage B1 (p < 0.05). L-lactate was significantly higher in stage C/D Chihuahuas than in any other group (p < 0.05), and stage B2 was significantly higher than that in H and stage B1 (p < 0.05). Intestinal mucosal injury risk was significantly higher in Chihuahuas with heart failure due to MMVD, suggesting that the risk could increase with worsening heart disease. This is the first study to investigate the intestinal complications of MMVD, and further investigations a needed in the future.

Gut-Barrier Disruption After Laparoscopic Versus Open Major Liver Resection in the Rat

BACKGROUND

Major liver resection may compromise gut-barrier function, increasing the risk of postoperative infectious complications. The aim of the present experimental study was to compare the effect of the laparoscopic versus the open technique for major liver resection on integrity as well as inflammatory and immune responses of the gut barrier.

METHODS

Wistar rats were subjected to open 70% hepatectomy (group H), laparoscopic 70% hepatectomy (group LH), sham operation (group S) or no intervention (group C). At various timepoints (1 hour-1 week) after operation, ileal tissue was excised for oxidative state assessment (TBARS levels), histopathologic examination, histomorphometric analysis, immunohistochemical assessment of the mitotic and apoptotic activity, and tissue expression of inflammatory (interleukin-6, tumor necrosis factor-α, nuclear factor-κB and vascular cell adhesion molecule-1) and immune response biomarkers (CD4⁺ and CD8⁺ T-lymphocytes) of the intestinal mucosa.

RESULTS

No changes were noted in oxidative state. The histopathologic profile was less deteriorated in group LH compared to group H. Intestinal mucosa atrophy was less intense in group LH compared to group H and was related to an equally compromised crypt cell mitotic activity. Tissue overexpression of interleukin-6, tumor necrosis factor-α, nuclear factor-κΒ, vascular cell adhesion molecule-1, CD4⁺, and CD8⁺ T-lymphocytes was less pronounced in group LH compared to group H.

CONCLUSION

The employment of the laparoscopic technique for major liver resection in the rat attenuated disruption of the gut barrier compared to the open procedure. This was related to less pronounced inflammatory and immune responses of the intestinal mucosa.

Association between enterocyte injury and fluid balance in patients with septic shock: a post hoc exploratory analysis of a prospective observational study

Background

The required fluid volume differs among patients with septic shock. Enterocyte injury caused by shock may increase the need for fluid by triggering a systematic inflammatory response or an ischemia-reperfusion injury in the presence of intestinal ischemia/necrosis. This study aimed to evaluate the association between enterocyte injury and positive fluid balance in patients with septic shock.

Methods

This study was a post hoc exploratory analysis of a prospective observational study that assessed the association between serum intestinal fatty acid-binding protein, a biomarker of enterocyte injury, and mortality in patients with septic shock. Intestinal fatty acid-binding protein levels were recorded on intensive care unit admission, and fluid balance was monitored from intensive care unit admission to Day 7. The association between intestinal fatty acid-binding protein levels at admission and the infusion balance during the early period after intensive care unit admission was evaluated. Multiple linear regression analysis, with adjustments for severity score and renal function, was performed.

Results

Overall, data of 57 patients were analyzed. Logarithmically transformed intestinal fatty acid-binding protein levels were significantly associated with cumulative fluid balance per body weight at 24 and 72 h post-intensive care unit admission both before (Pearson’s r = 0.490 [95% confidence interval: 0.263–0.666]; P < 0.001 and r = 0.479 [95% confidence interval: 0.240–0.664]; P < 0.001, respectively) and after (estimate, 14.4 [95% confidence interval: 4.1–24.7]; P = 0.007 and estimate, 26.9 [95% confidence interval: 11.0–42.7]; P = 0.001, respectively) adjusting for severity score and renal function.

Conclusions

Enterocyte injury was significantly associated with cumulative fluid balance at 24 and 72 h post-intensive care unit admission. Enterocyte injury in patients with septic shock may be related to excessive fluid accumulation during the early period after intensive care unit admission.

Intestinal fatty acid-binding protein is a biomarker for diagnosis of biliary tract infection

Background and Aim

Biliary tract infection (BTI) is an inflammatory disease and commonly associated with bacteremia. Delays in diagnosis or treatment of BTI cause high morbidity and mortality. However, an early diagnosis depends on appropriate clinical investigations. Appropriate biomarkers are urgently needed to improve the BTI diagnostic rate. We hypothesized that intestinal fatty acid‐binding protein (I‐FABP) might be a potential biomarker for BTI diagnosis.

Methods

We examined data from subjects aged ≥18 years diagnosed with BTI, including cholangitis and cholecystitis, whose blood samples were adequate for I‐FABP and zonulin assessment. We also collected blood samples from healthy volunteers as the control group. We excluded subjects in both groups who received steroids, antibiotics, or probiotics within 1 month before hospital admission (BTI cohort) or participation in this research (controls). The main study endpoint was to compare the diagnostic ability of I‐FABP to detect BTI in comparison with high‐sensitivity C‐reactive protein (hs‐CRP) and zonulin.

Results

The study collected the data of 51 patients with BTI and 35 healthy subjects. The receiver operating characteristic (ROC) area under the curve (AUC) for I‐FABP was 0.884 (95% confidence interval [CI]: 0.814–0.954), numerically higher than that for hs‐CRP (0.880; 0.785–0.976) and zonulin (0.570; 0.444–0.697). We estimated that the optimal cutoff value of I‐FABP was 2.1 ng/mL (sensitivity: 0.804; specificity: 0.829) for the diagnosis of BTI.

Conclusions

In summary, this study suggests that I‐FABP may be a potential alternative biomarker to hs‐CRP for diagnosing BTI. Further research should verify the use of I‐FABP as a marker for BTI diagnosis, but also for other inflammatory diseases.

S3QELs protect against diet-induced intestinal barrier dysfunction

The underlying causes of aging remain elusive, but may include decreased intestinal homeostasis followed by disruption of the intestinal barrier, which can be mimicked by nutrient‐rich diets. S3QELs are small‐molecule suppressors of site III_Qo electron leak; they suppress superoxide generation at complex III of the mitochondrial electron transport chain without inhibiting oxidative phosphorylation. Here we show that feeding different S3QELs to Drosophila on a high‐nutrient diet protects against greater intestinal permeability, greater enterocyte apoptotic cell number, and shorter median lifespan. Hif‐1α knockdown in enterocytes also protects, and blunts any further protection by S3QELs. Feeding S3QELs to mice on a high‐fat diet also protects against the diet‐induced increase in intestinal permeability. Our results demonstrate by inference of S3QEL use that superoxide produced by complex III in enterocytes contributes to diet‐induced intestinal barrier disruption in both flies and mice.

Effects of different ischemic preconditioning strategies on physiological and cellular mechanisms of intestinal ischemia/reperfusion injury: Implication from an isolated perfused rat small intestine model

Background

Intestinal ischemia/reperfusion (I/R)-injury often results in sepsis and organ failure and is of major importance in the clinic. A potential strategy to reduce I/R-injury is the application of ischemic preconditioning (IPC) during which repeated, brief episodes of I/R are applied. The aim of this study was to evaluate physiological and cellular effects of intestinal I/R-injury and to compare the influence of in-vivo IPC (iIPC) with ex-vivo IPC (eIPC), in which blood derived factors and nerval regulations are excluded.

Methods

Using an established perfused rat intestine model, effects of iIPC and eIPC on physiological as well as cellular mechanisms of I/R-injury (60 min hypoxia, 30 min reperfusion) were investigated. iIPC was applied by three reversible occlusions of the mesenteric artery in-vivo for 5 min followed by 5 min of reperfusion before isolating the small intestine, eIPC was induced by stopping the vascular perfusion ex-vivo 3 times for 5 min followed by 5 min of reperfusion after isolation of the intestine. Study groups (each N = 8–9 animals) were: iIPC, eIPC, I/R (iIPC group), I/R (eIPC group), iIPC+I/R, eIPC+I/R, no intervention/control (iIPC group), no intervention/control (eIPC group). Tissue morphology/damage, metabolic functions, fluid shifts and barrier permeability were evaluated. Cellular mechanisms were investigated using signaling arrays.

Results

I/R-injury decreased intestinal galactose uptake (iIPC group: p<0.001), increased vascular perfusion pressure (iIPC group: p<0.001; eIPC group: p<0.01) and attenuated venous flow (iIPC group: p<0.05) while lactate-to-pyruvate ratio (iIPC group, eIPC group: p<0.001), luminal flow (iIPC group: p<0.001; eIPC group: p<0.05), goblet cell ratio (iIPC group, eIPC group: p<0.001) and apoptosis (iIPC group, eIPC group: p<0.05) were all increased. Application of iIPC prior to I/R increased vascular galactose uptake (P<0.05) while eIPC had no significant impact on parameters of I/R-injury. On cellular level, I/R-injury resulted in a reduction of the phosphorylation of several MAPK signaling molecules. Application of iIPC prior to I/R increased phosphorylation of JNK2 and p38δ while eIPC enhanced CREB and GSK-3α/β phosphorylation.

Conclusion

Intestinal I/R-injury is associated with major physiological and cellular changes. However, the overall influence of the two different IPC strategies on the acute phase of intestinal I/R-injury is rather limited.

Pseudomonas aeruginosa Pneumonia Causes a Loss of Type-3 and an Increase in Type-1 Innate Lymphoid Cells in the Gut

BACKGROUND

Sepsis induces gut barrier dysfunction characterized by increased gut epithelial apoptosis and increased intestinal permeability. The cytokine IL-22 has been demonstrated to regulate gut barrier function. Type-3 innate lymphoid cells (ILC3) are the predominate source of IL-22 in the GI tract. We hypothesized that sepsis may cause changes to the gut ILC3/IL-22 axis.

MATERIALS AND METHODS

Sepsis was induced in WT and IL-22 KO mice by Pseudomonas aeruginosa pneumonia. Changes in gut-associated leukocyte populations were determined by flow-cytometry and ILC-associated transcripts were measured by RT-PCR. The effect of sepsis on gut permeability, pulmonary microbial burden, gut epithelial apoptosis, and survival was compared between WT and IL-22-/- mice.

RESULTS

Sepsis resulted in a significant decrease in the number of ILC3 in the gut, with a reciprocal increase in type-1 ILC (ILC1). Consistent with prior reports, sepsis was associated with increased gut permeability; however there was no difference in gut permeability, gut epithelial apoptosis, pulmonary microbial burden, or survival between WT and IL-22-/- mice.

CONCLUSIONS

Septic pneumonia causes a decrease in gut-associated ILC3 and an associated reciprocal increase in ILC1. This may reflect inflammation-induced conversion of ILC3 to ILC1. Constitutive systemic IL-22 deficiency does not alter sepsis-induced gut barrier dysfunction.

Plasma Markers of Disrupted Gut Permeability in Severe COVID-19 Patients

A disruption of the crosstalk between the gut and the lung has been implicated as a driver of severity during respiratory-related diseases. Lung injury causes systemic inflammation, which disrupts gut barrier integrity, increasing the permeability to gut microbes and their products. This exacerbates inflammation, resulting in positive feedback. We aimed to test whether severe Coronavirus disease 2019 (COVID-19) is associated with markers of disrupted gut permeability. We applied a multi-omic systems biology approach to analyze plasma samples from COVID-19 patients with varying disease severity and SARS-CoV-2 negative controls. We investigated the potential links between plasma markers of gut barrier integrity, microbial translocation, systemic inflammation, metabolome, lipidome, and glycome, and COVID-19 severity. We found that severe COVID-19 is associated with high levels of markers of tight junction permeability and translocation of bacterial and fungal products into the blood. These markers of disrupted intestinal barrier integrity and microbial translocation correlate strongly with higher levels of markers of systemic inflammation and immune activation, lower levels of markers of intestinal function, disrupted plasma metabolome and glycome, and higher mortality rate. Our study highlights an underappreciated factor with significant clinical implications, disruption in gut functions, as a potential force that may contribute to COVID-19 severity.

Multipotential and systemic effects of traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of disability and mortality of people at all ages. Biochemical, cellular and physiological events that occur during primary injury lead to a delayed and long-term secondary damage that can last from hours to years. Secondary brain injury causes tissue damage in the central nervous system and a subsequent strong and rapid inflammatory response that may lead to persistent inflammation. However, this inflammatory response is not limited to the brain. Inflammatory mediators are transferred from damaged brain tissue to the bloodstream and produce a systemic inflammatory response in peripheral organs, including the cardiovascular, pulmonary, gastrointestinal, renal and endocrine systems. Complications of TBI are associated with its multiple and systemic effects that should be considered in the treatment of TBI patients. Therefore, in this review, an attempt was made to examine the systemic effects of TBI in detail. It is hoped that this review will identify the mechanisms of injury and complications of TBI, and open a window for promising treatment in TBI complications.

Immunosuppressive effect of mesenchymal stem cells on lung and gut CD8+ T cells in lipopolysaccharide-induced acute lung injury in mice

Objectives

Acute lung injury (ALI) not only affects pulmonary function but also leads to intestinal dysfunction, which in turn contributes to ALI. Mesenchymal stem cell (MSC) transplantation can be a potential strategy in the treatment of ALI. However, the mechanisms of synergistic regulatory effects by MSCs on the lung and intestine in ALI need more in‐depth study.

Materials and methods

We evaluated the therapeutic effects of MSCs on the murine model of lipopolysaccharide (LPS)‐induced ALI through survival rate, histopathology and bronchoalveolar lavage fluid. Metagenomic sequencing was performed to assess the gut microbiota. The levels of pulmonary and intestinal inflammation and immune response were assessed by analysing cytokine expression and flow cytometry.

Results

Mesenchymal stem cells significantly improved the survival rate of mice with ALI, alleviated histopathological lung damage, improved intestinal barrier integrity, and reduced the levels of inflammatory cytokines in the lung and gut. Furthermore, MSCs inhibited the inflammatory response by decreasing the infiltration of CD8⁺ T cells in both small‐intestinal lymphocytes and Peyer's patches. The gut bacterial community diversity was significantly altered by MSC transplantation. Furthermore, depletion of intestinal bacterial communities with antibiotics resulted in more severe lung and gut damages and mortality, while MSCs significantly alleviated lung injury due to their immunosuppressive effect.

Conclusions

The present research indicates that MSCs attenuate lung and gut injury partly via regulation of the immune response in the lungs and intestines and gut microbiota, providing new insights into the mechanisms underlying the therapeutic effects of MSC treatment for LPS‐induced ALI.

[Stress ulcer prophylaxis for critically ill children: Routine use needs to be re-examined]

INTRODUCTION

Stress ulcer prophylaxis (SUP) is commonly used in Paediatric Intensive Care Units (PICUs). However, strong evidence for this practice is lacking and there is a dire need for paediatric randomized controlled trials (RCTs). Our aim was to assess the usefulness of SUP with omeprazole in critically ill children.

PATIENTS AND METHODS

We conducted a randomized, controlled open-label trial, including 144 children admitted into a PICU with a paediatric Sequential Organ Failure Assessment (pSOFA) score of less than 16. We randomly allocated patients to SUP with omeprazole or no SUP. The primary outcome was development of upper gastrointestinal bleeding or nosocomial infection.

RESULTS

The incidence of gastrointestinal bleeding was 27.1%, but clinically significant bleeding developed in only 5.6% of patients. We did not find a significant difference in the incidence of bleeding between the prophylaxis and control groups (27.8 vs. 26.4%; p = 0.85). We also did not find a significant difference between the group in the incidence of ventilator-associated pneumonia (VAP) (9.6 vs. 8.3%; p = 0.77). The incidence of central line-associated bloodstream infection (CLABSI) was higher in the prophylaxis group compared to the control group (30.6% vs. 12.5%; p = 0.014). None of the patients developed Clostridium difficile-associated diarrhoea. We did not find significant differences in mortality, length of PICU stay or duration of mechanical ventilation. Mechanical ventilation was an independent predictor of bleeding (OR 6.4; 95% CI, 2.73-14.9).

CONCLUSION

In PICU patients with mild to moderate organ dysfunction, omeprazole does not seem to be useful for prevention of gastrointestinal bleeding while at the same time increasing the risk of CLABSI. Thus, we recommend restricting SUP to mechanically ventilated children.

Impact of uric acid on liver injury and intestinal permeability following resuscitated hemorrhagic shock in rats

BACKGROUND

Multiorgan failure is a consequence of severe ischemia-reperfusion injury after traumatic hemorrhagic shock (HS), a major cause of mortality in trauma patients. Circulating uric acid (UA), released from cell lysis, is known to activate proinflammatory and proapoptotic pathways and has been associated with poor clinical outcomes among critically ill patients. Our group has recently shown a mediator role for UA in kidney and lung injury, but its role in liver and enteric damage after HS remains undefined. Therefore, the objective of this study was to evaluate the role of UA on liver and enteric injury after resuscitated HS.

METHODS

A murine model of resuscitated HS was treated during resuscitation with a recombinant uricase, a urate oxidase enzyme (rasburicase; Sanofi-Aventis, Canada Inc, Laval, Canada), to metabolize and reduce circulating UA. Biochemical analyses (liver enzymes, liver apoptotic, and inflammatory markers) were performed at 24 hours and 72 hours after HS. Physiological testing for enteric permeability and gut bacterial product translocation measurement (plasma endotoxin) were performed 72 hours after HS. In vitro, HT-29 cells were exposed to UA, and the expression of intercellular adhesion proteins (ZO-1, E-cadherin) was measured to evaluate the influence of UA on enteric permeability.

RESULTS

The addition of uricase to resuscitation significantly reduced circulating and liver UA levels after HS. It also prevented HS-induced hepatolysis and liver apoptotic/inflammatory mediators at 24 hours and 72 hours. Hemorrhagic shock-induced enteric hyperpermeability and endotoxemia were prevented with uricase.

CONCLUSIONS

After resuscitated HS, UA is an important mediator in liver and enteric injury. Uric acid represents a therapeutic target to minimize organ damage in polytrauma patients sustaining HS.

Transglutaminase 2 as a Marker for Inflammation and Therapeutic Target in Sepsis

Sepsis results in lethal organ malfunction due to dysregulated host response to infection, which is a condition with increasing prevalence worldwide. Transglutaminase 2 (TG2) is a crosslinking enzyme that forms a covalent bond between lysine and glutamine. TG2 plays important roles in diverse cellular processes, including extracellular matrix stabilization, cytoskeletal function, cell motility, adhesion, signal transduction, apoptosis, and cell survival. We have shown that the co-culture of Candida albicans and hepatocytes activates and induces the translocation of TG2 into the nucleus. In addition, the expression and activation of TG2 in liver macrophages was dramatically induced in the lipopolysaccharide-injected and cecal ligation puncture-operated mouse models of sepsis. Based on these findings and recently published research, we have reviewed the current understanding of the relationship between TG2 and sepsis. Following the genetic and pharmacological inhibition of TG2, we also assessed the evidence regarding the use of TG2 as a potential marker and therapeutic target in inflammation and sepsis.

PNU-282987 Attenuates Intestinal Epithelial Barrier Dysfunction in LPS-Induced Endotoxemia

PNU-282987, the α7 acetylcholine receptor(α7nAchR) agonist, has been repeatedly reported to play a key role in anti-inflammatory action of multiple disease. However, little is known about its effect on LPS-induced intestinal epithelial barrier dysfunction. This study investigated the protective effects and mechanisms of PNU-282987 on intestinal epithelial barrier dysfunction in lipopolysaccharide(LPS)-induced endotoxemic rats. Endotoxemia models were induced by intraperitoneal injection of 10 mg/kg LPS. In the endotoxemic group, results showed increases in ileum mucosal permeability, ultrastructural damage of tight junction and redistribution of zonula occludens-1, apoptosis of intestinal epithelial cells and caspase-3 activation. These changes were significantly improved after PNU-282987 administration(P < 0.05). Pretreatment with α-bungarotoxin before PNU-282987 administration reversed the effects of PNU-282987(P < 0.05). These results indicate that PNU-282987 exerts protective effects on intestinal epithelial barrier dysfunction in LPS-induced endotoxemic rats, and its mechanism may involve the improvement of zonula occludens-1 and inhibition of enterocyte apoptosis in an α7nAchR-dependent manner.

The clinical relevance of the microbiome when managing paediatric infectious diseases-Narrative review

In recent years, the field of infectious diseases has been hit by the overwhelming amount of information generated while the human microbiome is being disentangled. Based on the interaction between the microbiota and the immune system, the implications regarding infectious diseases are probably major and remain a challenge.

AIMS

This review was conceived as a comprehensive tool to provide an overview of the available evidence regarding the influence of the microbiome on infectious diseases in children.

METHODS

We present the main findings aroused from microbiome research in prevention, diagnosis and treatment of infectious disease under a paediatric perspective, to inform clinicians of the potential relevance of microbiome-related knowledge for translation to clinical practice.

RESULTS AND CONCLUSION

The evidence shown in this review highlights the numerous research gaps ahead and supports the need to move forward to integrating the so-called microbiome thinking into our routine clinical practice.

Effect of a fever in viral infections — the ‘Goldilocks’ phenomenon?

Acute infections, including those due to Coronaviridae and other viruses, often stimulate a febrile response. A mild fever appears to improve outcome; it appears to diminish viral replication by several mechanisms, including virion entry into host cells and genome transcription, and improving host defence mechanisms against the pathogen. However, a fever may also damage host cellular and tissue function and increase metabolic demands. At temperatures at the lower end of the febrile range, the benefit of the fever appears to outweigh the detrimental effects. However, at higher temperatures, the outcome worsens, suggesting that the disadvantages of fever on the host predominate. A non-infective fever is associated with a worse outcome at lower temperatures, suggesting that hyperthermia carries less benefit in the absence of infection. This review discusses the risks and benefits of a fever on the host response, focusing on the effects of a fever on viral replication and host response, and the detrimental effect on the host.

Sertraline and Citalopram Actions on Gut Barrier Function

INTRODUCTION

Disruption of intestinal barrier is a key component to various diseases. Whether barrier dysfunction is the cause or effect in these situations is still unknown, although it is believed that translocation of luminal content may initiate gastrointestinal or systemic inflammatory disorders. Since trauma- or infection-driven epithelial permeability depends on Toll-like receptor (TLR) activity, inhibition of TLR signaling has been proposed as a strategy to protect intestinal barrier integrity after infection or other pathological conditions. Recently, selective serotonin recapture inhibitors including sertraline and citalopram were shown to inhibit TLR-3 activity, but the direct effects of these antidepressant drugs on the gut mucosa barrier remain largely unexplored.

MATERIALS AND METHODS

To investigate this, two approaches were used: first, ex vivo studies were performed to evaluate sertraline and citalopram-driven changes in permeability in isolated intestinal tissue. Second, both compounds were tested for their preventive effects in a rat model of disrupted gut barrier, induced by a low protein (LP) diet.

RESULTS

Only sertraline was able to increase transepithelial electrical resistance in the rat colon both when used in an ex vivo (0.8 μg/mL, 180 min) or in vivo (30 mg/kg p.o., 20 days) fashion. However, citalopram (20 mg/kg p.o., 20 days), but not sertraline, prevented the increase in phospho-IRF3 protein, a marker of TLR-3 activation, in LP-rat ileum. Neither antidepressant affected locomotion, anxiety-like behaviours or stress-induced defecation.

CONCLUSION

Our data provides evidence to support the investigation of sertraline as therapeutic strategy to protect intestinal barrier function under life-threatening situations or chronic conditions associated with gut epithelial disruption.

Why is SARS-CoV-2 infection more severe in obese men? The gut lymphatics - Lung axis hypothesis

Consistent observations report increased severity of SARS-CoV-2 infection in overweight men with cardiovascular factors. As the visceral fat possesses an intense immune activity, is involved in metabolic syndrome and is at the crossroad between the intestines, the systemic circulation and the lung, we hypothesized that it plays a major role in severe forms of SARS-CoV-2 infection. SARS-CoV2 presents the ability to infect epithelial cells of the respiratory tract as well as the intestinal tract. Several factors may increase intestinal permeability including direct enterocyte damage by SARS-CoV2, systemic inflammatory response syndrome (SIRS) and epithelial ischemia secondary to SARS-CoV2- associated endothelial dysfunction. This increase permeability further leads to translocation of microbial components such as MAMPs (microbial-associated molecular pattern), triggering an inflammatory immune response by TLR-expressing cells of the mesentery fat (mostly macrophages and adipocytes). The pro-inflammatory cytokines produced by the mesentery fat mediates systemic inflammation and aggravate acute respiratory distress syndrome (ARDS) through the mesenteric lymph drainage.

Interleukin-10 and Zonulin Are Associated With Postoperative Delayed Gastric Emptying in Critically Ill Surgical Pediatric Patients: A Prospective Pilot Study

BACKGROUND

Impaired gastric emptying (GE) is associated with morbidity in surgical critically ill children. The relationship between inflammation, gut barrier integrity (lipopolysaccharide binding protein [LBP]; zonulin), and GE has not been described in this cohort.

METHODS

Children ≥2 years of age and requiring critical care after surgery were enrolled. Preoperative and postoperative levels of serum cytokines, LBP, and zonulin, and GE by the acetaminophen absorption test, were measured, allowing patients to serve as their own controls. Postoperative delayed GE was defined as a decrease in GE by ≥20% compared with preoperative GE. The following were examined : comparison between postoperative andpreoperative values, correlations between fold change (postoperative/preoperative) in study variables, and fold change in study variables between patients with and without postoperative delayed GE.

RESULTS

Twenty patients, median age 14 years (12.25, 18), 12 female, were included. Eight of 20 patients had postoperative delayed GE. Postoperative interleukin-6 (IL-6), IL-8, IL-10, and LBP were increased, and zonulin was decreased (P-values < .05). Fold change in IL-10 and zonulin were inversely correlated (ρ -0.618, P = .004). Patients with postoperative delayed GE had greater fold increase in IL-10 (P = .0159) and fold decrease in zonulin (P = .0160). Five of 7 (71%) patients with both fold increase in IL-10 and decrease in zonulin had delayed GE.

CONCLUSION

Postoperative changes in IL-10 and zonulin were associated with delayed GE in surgical critically ill children, which might suggest a mechanism to for delayed GE in postoperative inflammation and gut barrier dysregulation after surgery.

Rhubarb-Aconite Decoction (RAD) Drug-Containing Serum Alleviated Endotoxin-Induced Oxidative Stress Injury and Inflammatory Response in Caco-2 Cells In Vitro

Rhubarb-Aconite Decoction (RAD), a famous Chinese medicine prescription, has been widely used for treating intestinal injury. However, the effect of RAD on intestinal epithelial cells is unclear. The aim of this study was to investigate the effects of RAD drug-containing serum on the oxidative stress injury and inflammatory response induced by endotoxin (ET) in Caco-2 cells in vitro. Lipid peroxide malondialdehyde (MDA), lactate dehydrogenase (LDH), caspase-11, tumor necrosis factor-α(TNF-α), interleukin-3(IL-3), and cytokeratin (CK)18, adenosine triphosphate (ATP) activity, and intracellular free calcium ion levels were measured. The results showed that ET triggered the activation of caspase-11 and the massive release of TNF-α, increased the inhibitory rate of cell growth, MDA, and LDH expressions in Caco-2 cells. Moreover, RAD drug-containing serum could inhibit caspase-11 activation, decrease the release of TNF-α and IL-3, reduce intracellular free calcium ion, and enhance CK 18 expression and ATP activity. These novel findings demonstrated that ET-induced oxidative stress injury and inflammatory response of Caco-2 cells were improved by RAD drug-containing serum, indicating that RAD may be a good choice for the treatment of intestinal injury.

Selepressin, a novel selective V1A receptor agonist: Effect on mesenteric flow and gastric mucosa perfusion in the endotoxemic rabbit

Intestinal or mesenteric ischemia generally leads to inflammation and injury, potentially developing hypoxia, causing cell death and tissue necrosis. This in turn can lead to sepsis and shock. Conversely, following shock, the intestinal tract is a main organ to experience ischemic/reperfusion injury. Increased intestinal cell-membrane permeability through mesenteric ischemia provoking bacterial translocation and gut-barrier injury can lead to sepsis and multi-organ failure. Hypotension induced by systemic vasodilation and vascular leak in systemic inflammatory response syndrome and sepsis is countered by immediate fluid resuscitation and vasopressor administration, primarily norepinephrine (NE), with possible arginine vasopressin (AVP) supplementation, an agonist of vasopressin V_1A and V₂ receptors. Selepressin is a selective V_1A-receptor agonist, avoiding potential V₂ receptor-associated adverse effects. Selepressin, non-selective AVP, and NE effects on mesenteric blood flow (MBF) and gastric mucosa perfusion (GMP) were compared in control rabbits and a lipopolysaccharide-induced, fluid-resuscitated rabbit endotoxemia model. AVP induced a pronounced decrease in MBF and GMP in non-endotoxemic and endotoxemic rabbits, whereas the reduction after selepressin treatment was significantly less for both indicators in the endotoxemic animals. By contrast, NE increased the MBF and did not affect GMP in both groups. Selepressin and AVP induced a pronounced dose-dependent increase in mesenteric vascular resistance in non-endotoxemic and endotoxemic rabbits, tending to be less in endotoxemic animals, whereas a minor increase in both groups was observed with NE. Therefore, in this safety study, the risk for mesenteric ischemia on selepressin treatment was not inferior to AVP, being less in endotoxemic than in non-endotoxemic animals.

"Small" Intestinal Immunopathology Plays a "Big" Role in Lethal Cytokine Release Syndrome, and Its Modulation by Interferon-γ, IL-17A, and a Janus Kinase Inhibitor

Chimeric antigen receptor T cell (CART) therapy, administration of certain T cell-agonistic antibodies, immune check point inhibitors, coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) and Toxic shock syndrome (TSS) caused by streptococcal as well as staphylococcal superantigens share one common complication, that is T cell-driven cytokine release syndrome (CRS) accompanied by multiple organ dysfunction (MOD). It is not understood whether the failure of a particular organ contributes more significantly to the severity of CRS. Also not known is whether a specific cytokine or signaling pathway plays a more pathogenic role in precipitating MOD compared to others. As a result, there is no specific treatment available to date for CRS, and it is managed only symptomatically to support the deteriorating organ functions and maintain the blood pressure. Therefore, we used the superantigen-induced CRS model in HLA-DR3 transgenic mice, that closely mimics human CRS, to delineate the immunopathogenesis of CRS as well as to validate a novel treatment for CRS. Using this model, we demonstrate that (i) CRS is characterized by a rapid rise in systemic levels of several Th1/Th2/Th17/Th22 type cytokines within a few hours, followed by a quick decline. (ii) Even though multiple organs are affected, small intestinal immunopathology is the major contributor to mortality in CRS. (iii) IFN-γ deficiency significantly protected from lethal CRS by attenuating small bowel pathology, whereas IL-17A deficiency significantly increased mortality by augmenting small bowel pathology. (iv) RNA sequencing of small intestinal tissues indicated that IFN-γ-STAT1-driven inflammatory pathways combined with enhanced expression of pro-apoptotic molecules as well as extracellular matrix degradation contributed to small bowel pathology in CRS. These pathways were further enhanced by IL-17A deficiency and significantly down-regulated in mice lacking IFN-γ. (v) Ruxolitinib, a selective JAK-1/2 inhibitor, attenuated SAg-induced T cell activation, cytokine production, and small bowel pathology, thereby completely protecting from lethal CRS in both WT and IL-17A deficient HLA-DR3 mice. Overall, IFN-γ-JAK-STAT-driven pathways contribute to lethal small intestinal immunopathology in T cell-driven CRS.