Parallels in Sepsis and COVID-19 Conditions: Implications for Managing Severe COVID-19

Impact of HDAC inhibitors on macrophage polarization to enhance innate immunity against infections

Innate immunity plays an important role in host defense against pathogenic infections. It involves macrophage polarization into either the pro-inflammatory M1 or the anti-inflammatory M2 phenotype, influencing immune stimulation or suppression, respectively. Epigenetic changes during immune reactions contribute to long-term innate immunity imprinting on macrophage polarization. It is becoming increasingly evident that epigenetic modulators, such as histone deacetylase (HDAC) inhibitors (HDACi), enable the enhancement of innate immunity by tailoring macrophage polarization in response to immune stressors. In this review, we summarize current literature on the impact of HDACi and other epigenetic modulators on the functioning of macrophages during diseases that have a strong immune component, such as infections. Depending on the disease context and the chosen therapeutic intervention, HDAC1, HDAC2, HDAC3, HDAC6, or HDAC8 are particularly important in influencing macrophage polarization towards either M1 or M2 phenotypes. We anticipate that therapeutic strategies based on HDAC epigenetic mechanisms will provide a unique approach to boost immunity against disease challenges, including resistant infections.

Coordinated, multicellular patterns of transcriptional variation that stratify patient cohorts are revealed by tensor decomposition

Tissue-level and organism-level biological processes often involve the coordinated action of multiple distinct cell types. The recent application of single-cell assays to many individuals should enable the study of how donor-level variation in one cell type is linked to that in other cell types. Here we introduce a computational approach called single-cell interpretable tensor decomposition (scITD) to identify common axes of interindividual variation by considering joint expression variation across multiple cell types. scITD combines expression matrices from each cell type into a higher-order matrix and factorizes the result using the Tucker tensor decomposition. Applying scITD to single-cell RNA-sequencing data on 115 persons with lupus and 83 persons with coronavirus disease 2019, we identify patterns of coordinated cellular activity linked to disease severity and specific phenotypes, such as lupus nephritis. scITD results also implicate specific signaling pathways likely mediating coordination between cell types. Overall, scITD offers a tool for understanding the covariation of cell states across individuals, which can yield insights into the complex processes that define and stratify disease.

COVID-19-Associated Sepsis: Potential Role of Phytochemicals as Functional Foods and Nutraceuticals

The acute manifestations of coronavirus disease 2019 (COVID-19) exhibit the hallmarks of sepsis-associated complications that reflect multiple organ failure. The inflammatory cytokine storm accompanied by an imbalance in the pro-inflammatory and anti-inflammatory host response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to severe and critical septic shock. The sepsis signature in severely afflicted COVID-19 patients includes cellular reprogramming and organ dysfunction that leads to high mortality rates, emphasizing the importance of improved clinical care and advanced therapeutic interventions for sepsis associated with COVID-19. Phytochemicals of functional foods and nutraceutical importance have an incredible impact on the healthcare system, which includes the prevention and/or treatment of chronic diseases. Hence, in the present review, we aim to explore the pathogenesis of sepsis associated with COVID-19 that disrupts the physiological homeostasis of the body, resulting in severe organ damage. Furthermore, we have summarized the diverse pharmacological properties of some potent phytochemicals, which can be used as functional foods as well as nutraceuticals against sepsis-associated complications of SARS-CoV-2 infection. The phytochemicals explored in this article include quercetin, curcumin, luteolin, apigenin, resveratrol, and naringenin, which are the major phytoconstituents of our daily food intake. We have compiled the findings from various studies, including clinical trials in humans, to explore more into the therapeutic potential of each phytochemical against sepsis and COVID-19, which highlights their possible importance in sepsis-associated COVID-19 pathogenesis. We conclude that our review will open a new research avenue for exploring phytochemical-derived therapeutic agents for preventing or treating the life-threatening complications of sepsis associated with COVID-19.

Gas-exchange deficit and systemic hypoperfusion in COVID-19 and non-COVID-19 young adult patients with pneumonia

BACKGROUND

Lung damage leading to gas-exchange deficit and sepsis leading to systemic hypoperfusion are well-known features of severe pneumonia. Although frequently described in COVID-19, their prognostic impact in COVID-19-related pneumonia versus COVID-19-unrelated pneumonia has never been compared. This study assesses fundamental gas-exchange and hemodynamic parameters and explores their prognostic impact in COVID-19 pneumonia and non-COVID-19 pneumonia.

METHODS

We prospectively evaluated arterial pO2/FiO2, alveolar to arterial O2 gradient, shock index, and serum lactate in 126 COVID-19 pneumonia patients, aged 18-65, presenting to the emergency department with acute, non-hypercapnic respiratory failure. As a control group we identified 1:1 age-, sex-, and pO2/FiO2-matched COVID-19-urelated pneumonia patients. Univariate and multivariable predictors of 30-day survival were identified in both groups.

RESULTS

COVID-19 patients showed lower arterial serum lactate concentration (P<0.001) and shock index (P<0.001) values as compared to non-COVID-19 patients. While we did not observe differences in lactate concentration or in shock index values in deceased vs. surviving COVID-19 patients (P=0.7 and P=0.6, respectively), non-COVID-19 deceased patients showed significantly higher lactate and shock index than non-COVID-19 survivors (P<0.001 and P=0.03). The pO2/FiO2 was the most powerful determinant of survival by Cox regression multivariate analysis in COVID-19 patients (P=0.006), while it was lactate in non-COVID-19 patients (P=0.001).

CONCLUSIONS

As compared to COVID19-unrelated pneumonia, COVID-19 pneumonia outcome seems more strictly correlated to the extent of lung damage, rather than to the systemic circulatory and metabolic derangements typical of sepsis.

COVID-19, Possible Hepatic Pathways and Alcohol Abuse-What Do We Know up to 2023?

The pandemic period due to coronavirus disease 2019 (COVID-19) revolutionized all possible areas of global health. Significant consequences were also related to diverse extrapulmonary manifestations of this pathology. The liver was found to be a relatively common organ, beyond the respiratory tract, affected by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Multiple studies revealed the essential role of chronic liver disease (CLD) in the general outcome of coronavirus infection. Present concerns in this field are related to the direct hepatic consequences caused by COVID-19 and pre-existing liver disorders as risk factors for the severe course of the infection. Which mechanism has a key role in this phenomenon-previously existing hepatic disorder or acute liver failure due to SARS-CoV-2-is still not fully clarified. Alcoholic liver disease (ALD) constitutes another not fully elucidated context of coronavirus infection. Should the toxic effects of ethanol or already developed liver cirrhosis and its consequences be perceived as a causative or triggering factor of hepatic impairment in COVID-19 patients? In the face of these discrepancies, we decided to summarize the role of the liver in the whole picture of coronavirus infection, paying special attention to ALD and focusing on the pathological pathways related to COVID-19, ethanol toxicity and liver cirrhosis.

The unfolded protein response pathway as a possible link in the pathogenesis of COVID-19 and sepsis

The global impact of the COVID-19 pandemic has been substantial. Emerging evidence underscores a strong clinical connection between COVID-19 and sepsis. Numerous studies have identified the unfolded protein response (UPR) pathway as a crucial pathogenic pathway for both COVID-19 and sepsis, but it remains to be investigated whether this signaling pathway operates as a common pathogenic mechanism for both COVID-19 and sepsis. In this study, single-cell RNA-seq data and transcriptome data for COVID-19 and sepsis cases were downloaded from GEO (Gene Expression Omnibus). By analyzing the single-cell transcriptome data, we identified B cells as the critical cell subset and the UPR pathway as the critical signaling pathway. Based on the transcriptome data, a machine learning diagnostic model was then constructed using the interleaved genes of B-cell-related and UPR-pathway-related genes. We validated the diagnostic model using both internal and external datasets and found the accuracy and stability of this model to be extremely strong. Even after integrating our algorithmic model with the patient's clinical status, it continued to yield identical results, further emphasizing the reliability of this model. This study provides a novel molecular perspective on the pathogenesis of sepsis and COVID-19 at the single-cell level and suggests that these two diseases may share a common mechanism.

A hub gene signature as a therapeutic target and biomarker for sepsis and geriatric sepsis-induced ARDS concomitant with COVID-19 infection

Background

COVID-19 and sepsis represent formidable public health challenges, characterized by incompletely elucidated molecular mechanisms. Elucidating the interplay between COVID-19 and sepsis, particularly in geriatric patients suffering from sepsis-induced acute respiratory distress syndrome (ARDS), is of paramount importance for identifying potential therapeutic interventions to mitigate hospitalization and mortality risks.

Methods

We employed bioinformatics and systems biology approaches to identify hub genes, shared pathways, molecular biomarkers, and candidate therapeutics for managing sepsis and sepsis-induced ARDS in the context of COVID-19 infection, as well as co-existing or sequentially occurring infections. We corroborated these hub genes utilizing murine sepsis-ARDS models and blood samples derived from geriatric patients afflicted by sepsis-induced ARDS.

Results

Our investigation revealed 189 differentially expressed genes (DEGs) shared among COVID-19 and sepsis datasets. We constructed a protein-protein interaction network, unearthing pivotal hub genes and modules. Notably, nine hub genes displayed significant alterations and correlations with critical inflammatory mediators of pulmonary injury in murine septic lungs. Simultaneously, 12 displayed significant changes and correlations with a neutrophil-recruiting chemokine in geriatric patients with sepsis-induced ARDS. Of these, six hub genes (CD247, CD2, CD40LG, KLRB1, LCN2, RETN) showed significant alterations across COVID-19, sepsis, and geriatric sepsis-induced ARDS. Our single-cell RNA sequencing analysis of hub genes across diverse immune cell types furnished insights into disease pathogenesis. Functional analysis underscored the interconnection between sepsis/sepsis-ARDS and COVID-19, enabling us to pinpoint potential therapeutic targets, transcription factor-gene interactions, DEG-microRNA co-regulatory networks, and prospective drug and chemical compound interactions involving hub genes.

Conclusion

Our investigation offers potential therapeutic targets/biomarkers, sheds light on the immune response in geriatric patients with sepsis-induced ARDS, emphasizes the association between sepsis/sepsis-ARDS and COVID-19, and proposes prospective alternative pathways for targeted therapeutic interventions.

Are Patients With an International Classification of Diseases, 10th Edition Discharge Diagnosis Code for Sepsis Different in Regard to Demographics and Outcome Variables When Comparing Those With Sepsis Only to Those Also Diagnosed With COVID-19 or Those With a COVID-19 Diagnosis Alone?

OBJECTIVES

We analyzed whether patients with the International Classification of Diseases, 10th Edition (ICD-10) discharge diagnosis code for sepsis are different in regard to demographics and outcome variables when comparing those with sepsis only to those also diagnosed with COVID-19 or those with a COVID-19 diagnosis alone.

DESIGN

Retrospective cohort study.

SETTING

Nine hospitals in an academic health system.

PATIENTS

Patients with a final ICD-10 discharge diagnostic code for sepsis only, a diagnosis of COVID-19-only, or a final sepsis ICD-10 discharge code + a diagnosis of COVID-19 admitted to the hospital were analyzed for demographic and outcome differences between the cohorts.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 11,395 patients met inclusion criteria: 6,945 patients (60.9%) were ICD-10 sepsis code only, 3,294 patients (28.9%) were COVID-19 diagnosis-only, and 1,153 patients (10.1%) were sepsis ICD-10 code + COVID-19 diagnosis. Comparing sepsis ICD-10 code + COVID-19 diagnosis patients to sepsis ICD-10 code only and COVID-19 diagnosis-only patients, the sepsis ICD-10 code + COVID-19 diagnosis patients were: older (69 [58-78] vs 67 [56-77] vs 64 [51-76] yr), less likely to be female (40.3% vs 46.7% vs 49.5%), more frequently admitted to the ICU (59.3% [684/1,153] vs 54.9% [1,810/3,297] vs 15% [1,042/6,945]), more frequently required ventilatory support (39.3% [453/1,153] vs 31.8% [1,049/3,297] vs 6.0% [417/6,945]), had longer median hospital length of stay (9 [5,16] vs 5 [3,8] vs 7. [4,13] d), and were more likely to die in the hospital (39.2% [452/1,153] vs 22.3% [735/3,297] vs 6.4% [444/6,945]).

CONCLUSIONS

During the COVID-19 pandemic the sickest cohort of patients was those receiving an explicit ICD-10 code of sepsis + a COVID-19 diagnosis. A significant percentage of COVID-19 diagnosis-only patients appear to have been under-coded as they received a level of critical care (ICU admission; intubation) suggestive of the presence of acute organ dysfunction during their admission.

Identification of an Immune-Related Gene Diagnostic Model and Potential Drugs in Sepsis Using Bioinformatics and Pharmacogenomics Approaches

Purpose

Sepsis is an organ dysfunction with high mortality. Early identification, diagnosis, and effective treatment of sepsis are beneficial to the survival of patients. This study aimed to find potential diagnosis and immune-related genes, and drug targets, which could provide novel diagnostic and therapeutic markers for sepsis.

Patients and Methods

The GSE69063, GSE154918 and GSE28750 datasets were integrated to evaluate immune infiltration and identify differentially expressed genes (DEGs) and immune-related genes. Weighted gene co-expression network analysis (WGCNA) was applied to find the hub module related to immune score and sepsis. Immune-related key genes were screened out by taking interaction of DEGs, immune-related genes, and genes in hub module. Protein-protein interaction (PPI) analysis was used to further screen immune-related hub genes, followed by construction of a diagnostic model based on immune-related hub genes. Functional analysis and drug prediction of immune-related hub genes were, respectively, performed by David software and DGIdb database, followed by expression validation by reverse transcriptase polymerase chain reaction (RT-PCR).

Results

Totally, 93 immune-related key genes were identified between 561 DEGs, 1793 immune-related genes and 12,459 genes in the hub module of WGCNA. Through PPI analysis, a total of 5 diagnose and immune-related hub genes were further obtained, including IL7R, IL10, CD40LG, CD28 and LCN2. Relationship pairs between these 5 genes and immune cell were identified, including LCN2/IL7R/CD28-activated dendritic cell and IL10-immature B cell. Based on pharmacogenomics, 17 candidate drugs might interact with IL 10, including CYCLOSPORINE. Six candidate drugs might interact with CD28 and 11 with CD40LG, CD40LG and CD28 were drug targets of ALDESLEUKIN. Four significantly enriched signaling pathways were identified, such as T cell receptor signaling pathway, NF-kappa B signaling pathway and JAK-STAT signaling pathway.

Conclusion

The 5-gene diagnostic model could be used to diagnose and guide clinical immunotherapy for sepsis.

TGF-β uncouples glycolysis and inflammation in macrophages and controls survival during sepsis

Changes in metabolism of macrophages are required to sustain macrophage activation in response to different stimuli. We showed that the cytokine TGF-β (transforming growth factor-β) regulates glycolysis in macrophages independently of inflammatory cytokine production and affects survival in mouse models of sepsis. During macrophage activation, TGF-β increased the expression and activity of the glycolytic enzyme PFKL (phosphofructokinase-1 liver type) and promoted glycolysis but suppressed the production of proinflammatory cytokines. The increase in glycolysis was mediated by an mTOR-c-MYC-dependent pathway, whereas the inhibition of cytokine production was due to activation of the transcriptional coactivator SMAD3 and suppression of the activity of the proinflammatory transcription factors AP-1, NF-κB, and STAT1. In mice with LPS-induced endotoxemia and experimentally induced sepsis, the TGF-β-induced enhancement in macrophage glycolysis led to decreased survival, which was associated with increased blood coagulation. Analysis of septic patient cohorts revealed that the expression of PFKL, TGFBRI (which encodes a TGF-β receptor), and F13A1 (which encodes a coagulation factor) in myeloid cells positively correlated with COVID-19 disease. Thus, these results suggest that TGF-β is a critical regulator of macrophage metabolism and could be a therapeutic target in patients with sepsis.

An Update on Toll-like Receptor 2, Its Function and Dimerization in Pro- and Anti-Inflammatory Processes

While a certain level of inflammation is critical for humans to survive infection and injury, a prolonged inflammatory response can have fatal consequences. Pattern recognition Toll-like receptors (TLRs) are key players in the initiation of an inflammatory process. TLR2 is one of the most studied pattern recognition receptors (PRRs) and is known to form heterodimers with either TLR1, TLR4, TLR6, and TLR10, allowing it to recognize a wide range of pathogens. Although a large number of studies have been conducted over the past decades, there are still many unanswered questions regarding TLR2 mechanisms in health and disease. In this review, we provide an up-to-date overview of TLR2, including its homo- and heterodimers. Furthermore, we will discuss the pro- and anti-inflammatory properties of TLR2 and recent findings in prominent TLR2-associated infectious and neurodegenerative diseases.

Presepsin levels and COVID-19 severity: a systematic review and meta-analysis

Plasmatic presepsin (PSP) is a novel biomarker reported to be useful for sepsis diagnosis and prognosis. During the pandemic, only few studies highlighted a possible correlation between PSP and COVID-19 severity, but results remain inconsistent. The present study aims to establish the correlation between PSP and COVID-19 severity. English-language papers assessing a correlation between COVID-19 and PSP from MEDLINE, PubMed, Google Scholar, Cochrane Library, MeSH, LitCovid NLM, EMBASE, CINAHL Plus and the World Health Organization (WHO) website, published from January 2020 were considered with no publication date limitations. Two independent reviewers performed data abstraction and quality assessment, and one reviewer resolved inconsistencies. The protocol was registered on PROSPERO (CRD42022325971).Fifteen articles met our eligibility criteria. The aggregate study population included 1373 COVID-19 patients who had undergone a PSP assessment. The random-effect meta-analysis was performed in 7 out of 15 selected studies, considering only those reporting the mean PSP levels in low- and high-severity cases (n = 707).The results showed that the pooled mean difference of PSP levels between high- and low-severity COVID-19 patients was 441.70 pg/ml (95%CI: 150.40-732.99 pg/ml).Our data show that presepsin is a promising biomarker that can express COVID-19 severity.

Changes in Cortisol Secretion and Corticosteroid Receptors in COVID-19 and Non COVID-19 Critically Ill Patients with Sepsis/Septic Shock and Scope for Treatment

Sepsis is associated with dysregulated cortisol secretion, leading to abnormal levels of cortisol in the blood. In the early stages of the condition, cortisol levels are typically elevated due to increased secretion from the adrenal glands. However, as the disease progresses, cortisol levels may decline due to impaired adrenal function, leading to relative adrenal insufficiency. The latter is thought to be caused by a combination of factors, including impaired adrenal function, decreased production of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) by the hypothalamus and pituitary gland, and increased breakdown of cortisol. The dysregulation of cortisol secretion in sepsis is thought to contribute to the pathophysiology of the disease by impairing the body's ability to mount an appropriate inflammatory response. Given the dysregulation of cortisol secretion and corticosteroid receptors in sepsis, there has been considerable interest in the use of steroids as a treatment. However, clinical trials have yielded mixed results and corticosteroid use in sepsis remains controversial. In this review, we will discuss the changes in cortisol secretion and corticosteroid receptors in critically ill patients with sepsis/septic shock. We will also make special note of COVID-19 patients, who presented a recent challenge for ICU management, and explore the scope for corticosteroid administration in both COVID-19 and non-COVID-19 septic patients.

Linking Sepsis with chronic arterial hypertension, diabetes mellitus, and socioeconomic factors in the United States: A scoping review

RATIONALE

Sepsis is a syndrome of life-threatening organ dysfunction caused by a dysregulated host immune response to infection. Social risk factors including location and poverty are associated with sepsis-related disparities. Understanding the social and biological phenotypes linked with the incidence of sepsis is warranted to identify the most at-risk populations. We aim to examine how factors in disadvantage influence health disparities related to sepsis.

METHODS

A scoping review was performed for English-language articles published in the United States from 1990 to 2022 on PubMed, Web of Science, and Scopus. Of the 2064 articles found, 139 met eligibility criteria and were included for review.

RESULTS

There is consistency across the literature of disproportionately higher rates of sepsis incidence, mortality, readmissions, and associated complications, in neighborhoods with socioeconomic disadvantage and significant poverty. Chronic arterial hypertension and diabetes mellitus also occur more frequently in the same geographic distribution as sepsis, suggesting a potential shared pathophysiology.

CONCLUSIONS

The distribution of chronic arterial hypertension, diabetes mellitus, social risk factors associated with socioeconomic disadvantage, and sepsis incidence, are clustered in specific geographical areas and linked by endothelial dysfunction. Such population factors can be utilized to create equitable interventions aimed at mitigating sepsis incidence and sepsis-related disparities.

COVID-19 and liver injury: Pathophysiology, risk factors, outcome and management in special populations

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 is an ongoing health concern. In addition to affecting the respiratory system, COVID-19 can potentially damage other systems in the body, leading to extra-pulmonary manifestations. Hepatic manifestations are among the common consequences of COVID-19. Although the precise mechanism of liver injury is still questionable, several mechanisms have been hypothesized, including direct viral effect, cytokine storm, hypoxic-ischemic injury, hypoxia-reperfusion injury, ferroptosis, and hepatotoxic medications. Risk factors of COVID-19-induced liver injury include severe COVID-19 infection, male gender, advanced age, obesity, and underlying diseases. The presentations of liver involvement comprise abnormalities in liver enzymes and radiologic findings, which can be utilized to predict the prognosis. Increased gamma-glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase levels with hypoalbuminemia can indicate severe liver injury and anticipate the need for intensive care units’ hospitalization. In imaging, a lower liver-to-spleen ratio and liver computed tomography attenuation may indicate a more severe illness. Furthermore, chronic liver disease patients are at a higher risk for severe disease and death from COVID-19. Nonalcoholic fatty liver disease had the highest risk of advanced COVID-19 disease and death, followed by metabolic-associated fatty liver disease and cirrhosis. In addition to COVID-19-induced liver injury, the pandemic has also altered the epidemiology and pattern of some hepatic diseases, such as alcoholic liver disease and hepatitis B. Therefore, it warrants special vigilance and awareness by healthcare professionals to screen and treat COVID-19-associated liver injury accordingly.

Molecular Analysis of SARS-CoV-2 Spike Protein-Induced Endothelial Cell Permeability and vWF Secretion

Coronavirus disease COVID-19, which is caused by severe acute respiratory syndrome coronavirus SARS-CoV-2, has become a worldwide pandemic in recent years. In addition to being a respiratory disease, COVID-19 is a 'vascular disease' since it causes a leaky vascular barrier and increases blood clotting by elevating von Willebrand factor (vWF) levels in the blood. In this study, we analyzed in vitro how the SARS-CoV-2 spike protein S1 induces endothelial cell (EC) permeability and its vWF secretion, and the underlying molecular mechanism for it. We showed that the SARS-CoV-2 spike protein S1 receptor-binding domain (RBD) is sufficient to induce endothelial permeability and vWF-secretion through the angiotensin-converting enzyme (ACE)2 in an ADP-ribosylation factor (ARF)6 activation-dependent manner. However, the mutants, including those in South African and South Californian variants of SARS-CoV-2, in the spike protein did not affect its induced EC permeability and vWF secretion. In addition, we have identified a signaling cascade downstream of ACE2 for the SARS-CoV-2 spike protein-induced EC permeability and its vWF secretion by using pharmacological inhibitors. The knowledge gained from this study could be useful in developing novel drugs or repurposing existing drugs for treating infections of SARS-CoV-2, particularly those strains that respond poorly to the existing vaccines.

Dysregulated Iron Homeostasis as Common Disease Etiology and Promising Therapeutic Target

Iron is irreplaceably required for animal and human cells as it provides the activity center for a wide variety of essential enzymes needed for energy production, nucleic acid synthesis, carbon metabolism and cellular defense. However, iron is toxic when present in excess and its uptake and storage must, therefore, be tightly regulated to avoid damage. A growing body of evidence indicates that iron dysregulation leading to excess quantities of free reactive iron is responsible for a wide range of otherwise discrete diseases. Iron excess can promote proliferative diseases such as infections and cancer by supplying iron to pathogens or cancer cells. Toxicity from reactive iron plays roles in the pathogenesis of various metabolic, neurological and inflammatory diseases. Interestingly, a common underlying aspect of these conditions is availability of excess reactive iron. This underpinning aspect provides a potential new therapeutic avenue. Existing hematologically used iron chelators to take up excess iron have shown serious limitations for use but new purpose-designed chelators in development show promise for suppressing microbial pathogen and cancer cell growth, and also for relieving iron-induced toxicity in neurological and other diseases. Hepcidin and hepcidin agonists are also showing promise for relieving iron dysregulation. Harnessing iron-driven reactive oxygen species (ROS) generation with ferroptosis has shown promise for selective destruction of cancer cells. We review biological iron requirements, iron regulation and the nature of iron dysregulation in various diseases. Current results pertaining to potential new therapies are also reviewed.

Stratification of COVID-19 Severity Using SeptiCyte RAPID, a Novel Host Immune Response Test

SeptiCyte® RAPID is a gene expression assay measuring the relative expression levels of host response genes PLA2G7 and PLAC8, indicative of a dysregulated immune response during sepsis. As severe forms of COVID-19 may be considered viral sepsis, we evaluated SeptiCyte RAPID in a series of 94 patients admitted to Foch Hospital (Suresnes, France) with proven SARS-CoV-2 infection. EDTA blood was collected in the emergency department (ED) in 67 cases, in the intensive care unit (ICU) in 23 cases and in conventional units in 4 cases. SeptiScore (0-15 scale) increased with COVID-19 severity. Patients in ICU had the highest SeptiScores, producing values comparable to 8 patients with culture-confirmed bacterial sepsis. Receiver operating characteristic (ROC) curve analysis had an area under the curve (AUC) of 0.81 for discriminating patients requiring ICU admission from patients who were immediately discharged or from patients requiring hospitalization in conventional units. SeptiScores increased with the extent of the lung injury. For 68 patients, a chest computed tomography (CT) scan was performed within 24 h of COVID-19 diagnosis. SeptiScore >7 suggested lung injury ≥50% (AUC = 0.86). SeptiCyte RAPID was compared to other biomarkers for discriminating Critical + Severe COVID-19 in ICU, versus Moderate + Mild COVID-19 not in ICU. The mean AUC for SeptiCyte RAPID was superior to that of any individual biomarker or combination thereof. In contrast to C-reactive protein (CRP), correlation of SeptiScore with lung injury was not impacted by treatment with anti-inflammatory agents. SeptiCyte RAPID can be a useful tool to identify patients with severe forms of COVID-19 in ED, as well as during follow-up.

A Potential Role of the Spike Protein in Neurodegenerative Diseases: A Narrative Review

Human prion protein and prion-like protein misfolding are widely recognized as playing a causal role in many neurodegenerative diseases. Based on in vitro and in vivo experimental evidence relating to prion and prion-like disease, we extrapolate from the compelling evidence that the spike glycoprotein of SARS-CoV-2 contains extended amino acid sequences characteristic of a prion-like protein to infer its potential to cause neurodegenerative disease. We propose that vaccine-induced spike protein synthesis can facilitate the accumulation of toxic prion-like fibrils in neurons. We outline various pathways through which these proteins could be expected to distribute throughout the body. We review both cellular pathologies and the expression of disease that could become more frequent in those who have undergone mRNA vaccination. Specifically, we describe the spike protein's contributions, via its prion-like properties, to neuroinflammation and neurodegenerative diseases; to clotting disorders within the vasculature; to further disease risk due to suppressed prion protein regulation in the context of widely prevalent insulin resistance; and to other health complications. We explain why these prion-like characteristics are more relevant to vaccine-related mRNA-induced spike proteins than natural infection with SARS-CoV-2. We note with an optimism an apparent loss of prion-like properties among the current Omicron variants. We acknowledge that the chain of pathological events described throughout this paper is only hypothetical and not yet verified. We also acknowledge that the evidence we usher in, while grounded in the research literature, is currently largely circumstantial, not direct. Finally, we describe the implications of our findings for the general public, and we briefly discuss public health recommendations we feel need urgent consideration. An earlier version of this article was previously posted to the Authorea preprint server on August 16, 2022.

Extracellular Vesicles: New Players in the Mechanisms of Sepsis- and COVID-19-Related Thromboinflammation

Sepsis and COVID-19 patients often manifest an imbalance in inflammation and coagulation, a complex pathological mechanism also named thromboinflammation, which strongly affects patient prognosis. Extracellular vesicles (EVs) are nanoparticles released by cells into extracellular space that have a relevant role in cell-to-cell communication. Recently, EVs have been shown to act as important players in a variety of pathologies, including cancer and cardiovascular disease. The biological properties of EVs in the mechanisms of thromboinflammation during sepsis and COVID-19 are still only partially known. Herein, we summarize the current experimental evidence on the role of EVs in thromboinflammation, both in bacterial sepsis and in COVID-19. A better understanding of EV involvement in these processes could be useful in describing novel diagnostic and therapeutic applications of EVs in these diseases.

COMBATdb: a database for the COVID-19 Multi-Omics Blood ATlas

Advances in our understanding of the nature of the immune response to SARS-CoV-2 infection, and how this varies within and between individuals, is important in efforts to develop targeted therapies and precision medicine approaches. Here we present a database for the COvid-19 Multi-omics Blood ATlas (COMBAT) project, COMBATdb (https://db.combat.ox.ac.uk). This enables exploration of multi-modal datasets arising from profiling of patients with different severities of illness admitted to hospital in the first phase of the pandemic in the UK prior to vaccination, compared with community cases, healthy controls, and patients with all-cause sepsis and influenza. These data include whole blood transcriptomics, plasma proteomics, epigenomics, single-cell multi-omics, immune repertoire sequencing, flow and mass cytometry, and cohort metadata. COMBATdb provides access to the processed data in a well-defined framework of samples, cell types and genes/proteins that allows exploration across the assayed modalities, with functionality including browse, search, download, calculation and visualisation via shiny apps. This advances the ability of users to leverage COMBAT datasets to understand the pathogenesis of COVID-19, and the nature of specific and shared features with other infectious diseases.

Severe COVID-19 and non-COVID-19 severe sepsis converge transcriptionally after a week in the intensive care unit, indicating common disease mechanisms

Introduction

Severe COVID-19 and non-COVID-19 pulmonary sepsis share pathophysiological, immunological, and clinical features. To what extent they share mechanistically-based gene expression trajectories throughout hospitalization was unknown. Our objective was to compare gene expression trajectories between severe COVID-19 patients and contemporaneous non-COVID-19 severe sepsis patients in the intensive care unit (ICU).

Methods

In this prospective single-center observational cohort study, whole blood was drawn from 20 COVID-19 patients and 22 non-COVID-19 adult sepsis patients at two timepoints: ICU admission and approximately a week later. RNA-Seq was performed on whole blood to identify differentially expressed genes and significantly enriched pathways.

Results

At ICU admission, despite COVID-19 patients being almost clinically indistinguishable from non-COVID-19 sepsis patients, COVID-19 patients had 1,215 differentially expressed genes compared to non-COVID-19 sepsis patients. After one week in the ICU, the number of differentially expressed genes dropped to just 9 genes. This drop coincided with decreased expression of antiviral genes and relatively increased expression of heme metabolism genes over time in COVID-19 patients, eventually reaching expression levels seen in non-COVID-19 sepsis patients. Both groups also had similar underlying immune dysfunction, with upregulation of immune processes such as "Interleukin-1 signaling" and "Interleukin-6/JAK/STAT3 signaling" throughout disease compared to healthy controls.

Discussion

Early on, COVID-19 patients had elevated antiviral responses and suppressed heme metabolism processes compared to non-COVID-19 severe sepsis patients, although both had similar underlying immune dysfunction. However, after one week in the ICU, these diseases became indistinguishable on a gene expression level. These findings highlight the importance of early antiviral treatment for COVID-19, the potential for heme-related therapeutics, and consideration of immunomodulatory therapies for both diseases to treat shared immune dysfunction.

Transcriptional reprogramming from innate immune functions to a pro-thrombotic signature by monocytes in COVID-19

Although alterations in myeloid cells have been observed in COVID-19, the specific underlying mechanisms are not completely understood. Here, we examine the function of classical CD14+ monocytes in patients with mild and moderate COVID-19 during the acute phase of infection and in healthy individuals. Monocytes from COVID-19 patients display altered expression of cell surface receptors and a dysfunctional metabolic profile that distinguish them from healthy monocytes. Secondary pathogen sensing ex vivo leads to defects in pro-inflammatory cytokine and type-I IFN production in moderate COVID-19 cases, together with defects in glycolysis. COVID-19 monocytes switch their gene expression profile from canonical innate immune to pro-thrombotic signatures and are functionally pro-thrombotic, both at baseline and following ex vivo stimulation with SARS-CoV-2. Transcriptionally, COVID-19 monocytes are characterized by enrichment of pathways involved in hemostasis, immunothrombosis, platelet aggregation and other accessory pathways to platelet activation and clot formation. These results identify a potential mechanism by which monocyte dysfunction may contribute to COVID-19 pathology.

Development and Characterization of Phage-Display-Derived Novel Human Monoclonal Antibodies against the Receptor Binding Domain of SARS-CoV-2

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in an ongoing global pandemic crisis, caused by the life-threatening illness coronavirus disease 2019 (COVID-19). Thus, the rapid development of monoclonal antibodies (mAbs) to cope with COVID-19 is urgently necessary. In this study, we used phage display to develop four human mAbs specific to the receptor-binding domain (RBD) of SARS-CoV-2. Our intensive in vitro functional analyses demonstrated that K102.1, an anti-SARS-CoV-2 RBD-specific mAb, exerted potent neutralizing activity against pseudoviral and live viral infection and the interaction between SARS-CoV-2 RBD and human angiotensin-converting enzyme 2. Monotherapy with K102.1 also revealed the therapeutic potential against SARS-CoV-2 infection in vivo. Further, this study developed a sandwich enzyme-linked immunosorbent assay with a non-competing mAb pair, K102.1 and K102.2, that accurately detected the RBDs of SARS-CoV-2 wild-type and variants with high sensitivity in the picomolar range. These findings suggest that the phage-display-based mAb selection from an established antibody library may be an effective strategy for the rapid development of mAbs against the constantly evolving SARS-CoV-2.

Immunopathology of chronic critical illness in sepsis survivors: Role of abnormal myelopoiesis

Sepsis remains the single most common cause of mortality and morbidity in hospitalized patients requiring intensive care. Although earlier detection and improved treatment bundles have reduced in-hospital mortality, long-term recovery remains dismal. Sepsis survivors who experience chronic critical illness often demonstrate persistent inflammation, immune suppression, lean tissue wasting, and physical and functional cognitive declines, which often last in excess of 1 year. Older patients and those with preexisting comorbidities may never fully recover and have increased mortality compared with individuals who restore their immunologic homeostasis. Many of these responses are shared with individuals with advanced cancer, active autoimmune diseases, chronic obstructive pulmonary disease, and chronic renal disease. Here, we propose that this resulting immunologic endotype is secondary to a persistent maladaptive reprioritization of myelopoiesis and pathologic activation of myeloid cells. Driven in part by the continuing release of endogenous alarmins from chronic organ injury and muscle wasting, as well as by secondary opportunistic infections, ongoing myelopoiesis at the expense of lymphopoiesis and erythropoiesis leads to anemia, recurring infections, and lean tissue wasting. Early recognition and intervention are required to interrupt this pathologic activation of myeloid populations.

Role of miRNA dysregulation in sepsis

Background

Sepsis is defined as a state of multisystem organ dysfunction secondary to a dysregulated host response to infection and causes millions of deaths worldwide annually. Novel ways to counteract this disease are needed and such tools may be heralded by a detailed understanding of its molecular pathogenesis. MiRNAs are small RNA molecules that target mRNAs to inhibit or degrade their translation and have important roles in several disease processes including sepsis.

Main body

The current review adopted a strategic approach to analyzing the widespread literature on the topic of miRNAs and sepsis. A pubmed search of “miRNA or microRNA or small RNA and sepsis not review” up to and including January 2021 led to 1140 manuscripts which were reviewed. Two hundred and thirty-three relevant papers were scrutinized for their content and important themes on the topic were identified and subsequently discussed, including an in-depth look at deregulated miRNAs in sepsis in peripheral blood, myeloid derived suppressor cells and extracellular vesicles.

Conclusion

Our analysis yielded important observations. Certain miRNAs, namely miR-150 and miR-146a, have consistent directional changes in peripheral blood of septic patients across numerous studies with strong data supporting a role in sepsis pathogenesis. Furthermore, a large body of literature show miRNA signatures of clinical relevance, and lastly, many miRNAs deregulated in sepsis are associated with the process of endothelial dysfunction. This review offers a widespread, up-to-date and detailed discussion of the role of miRNAs in sepsis and is meant to stimulate further work in the field due to the potential of these small miRNAs in prompt diagnostics, prognostication and therapeutic agency.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00527-z.

Sepsis: Immunopathology, Immunotherapies, and Future Perspectives

Sepsis is a syndrome that includes physiological, pathological, and biochemical abnormalities resulting from the host immune response to infection. Despite the improved treatment modalities in recent years, the incidence and mortality of sepsis are still increasing. Sepsis immunopathology is increasingly attracting the attention of researchers. The successes experienced with immunotherapeutics in the treatment of cancer and coronavirus disease 2019, which are diseases with similar pathophysiological features and common immune defects with sepsis, have given rise to the hope that similar successes can be achieved in the treatment of sepsis. In this review, future perspectives on the immunopathology of sepsis and immunotherapeutics are presented to improve the current understanding of the disease.

Impact of COVID-19 on Non-Pulmonary Critical Illness: Prevalence, Clinical Manifestations, Management, and Outcomes

Although respiratory manifestations are the most common driver of hospitalization, SARS-CoV-2 infection has a wide range of manifestations, including multisystem organ failure in severe cases. This review discusses the prevalence, pathophysiology, clinical manifestations, treatment, and outcomes of nonpulmonary organ dysfunction from SARS-CoV2, including renal, liver, cardiac, neurologic, and coagulation system dysfunction. At this time, management largely focuses on supportive care practices that are applicable regardless of the cause of organ injury.

Alteration in Redox Status and Lipoprotein Profile in COVID-19 Patients with Mild, Moderate, and Severe Pneumonia

Background

Metabolic alterations, particularly disorders of lipoprotein metabolism in COVID-19, may affect the course and outcome of the disease. This study aims at evaluating the lipoprotein profile and redox status in SARS-CoV-2 infected patients with different pneumonia severity and their association with lethal outcomes.

Methods

The prospective cohort study was performed on 98 COVID-19 patients with mild, moderate, and severe pneumonia. Lipid and inflammatory parameters, lipoprotein subclasses, and redox status biomarkers were determined at the study entry and after one week.

Results

Compared to patients with mild and moderate pneumonia, severely ill patients had higher oxidised low-density lipoprotein (oxLDL) and malondialdehyde levels and lower high-density lipoprotein cholesterol (HDL-C) concentrations and paraoxonase 1 activity. Reduction in the proportion of large HDL 2a subclasses with a concomitant increase in the proportion of smallest HDL 3c and small dense LDL (sdLDL) particles was observed in patients with severe disease during the time. However, these changes were reversed in the mild and moderate groups. The results showed a positive association between changes in oxLDL and total antioxidative status. However, prooxidants and antioxidants in plasma were lower in patients with lethal outcomes.

Conclusions

Increased levels of oxLDL and sdLDL particles may contribute to the severity of COVID-19. The role of oxidative stress should be clarified in further studies, mainly its association with lethal outcomes.

An immune dysfunction score for stratification of patients with acute infection based on whole-blood gene expression

Dysregulated host responses to infection can lead to organ dysfunction and sepsis, causing millions of global deaths each year. To alleviate this burden, improved prognostication and biomarkers of response are urgently needed. We investigated the use of whole-blood transcriptomics for stratification of patients with severe infection by integrating data from 3149 samples from patients with sepsis due to community-acquired pneumonia or fecal peritonitis admitted to intensive care and healthy individuals into a gene expression reference map. We used this map to derive a quantitative sepsis response signature (SRSq) score reflective of immune dysfunction and predictive of clinical outcomes, which can be estimated using a 7- or 12-gene signature. Last, we built a machine learning framework, SepstratifieR, to deploy SRSq in adult and pediatric bacterial and viral sepsis, H1N1 influenza, and COVID-19, demonstrating clinically relevant stratification across diseases and revealing some of the physiological alterations linking immune dysregulation to mortality. Our method enables early identification of individuals with dysfunctional immune profiles, bringing us closer to precision medicine in infection.

Pathway analysis of sepsis-induced changes gene expression

Background

Sepsis reaction is a response to an infection composed of genetic elements. This research aims to better understand how sepsis affects the molecular pathways in whole blood samples.

Methods

Whole blood samples from healthy controls (n = 18), sepsis nonsurvivors (n = 9), and sepsis survivors (n = 26) were retrieved from the gene expression omnibus (GEO) collection of the national center for biotechnology information (NCBI) (accession number GSE54514). The NCBI's GEO2R program was used to determine differential expression, and the ingenuity pathway analysis (IPA) software was utilized to do a pathway analysis.

Results

In sepsis patients, 2672 genes were substantially differently expressed (p value 0.05). One thousand three hundred four genes were overexpressed, and one thousand three hundred sixty-eight were under-expressed. The inhibition of ARE-mediated mRNA degradation pathway and the Pl3K/AKT signaling spliceosomal cycle were the most significant canonical pathways identified by ingenuity pathway analysis (IPA). The IPA upstream analysis predicted the ESR1, SIRT1, and PTPRR proteins, and the drugs filgrastim and fluticasone were top transcriptional regulators.

Conclusions

The inhibition of ARE-mediated mRNA degradation pathway and the Pl3K/AKT signaling spliceosomal cycle were highlighted as essential pathways of inflammation by IPA, indicating widespread cancer owing to sepsis. Our data imply that sepsis considerably influences gene pathways in whole blood samples, pointing to possible targets for sepsis treatment.

Discovering common pathogenetic processes between COVID-19 and sepsis by bioinformatics and system biology approach

Corona Virus Disease 2019 (COVID-19), an acute respiratory infectious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has spread rapidly worldwide, resulting in a pandemic with a high mortality rate. In clinical practice, we have noted that many critically ill or critically ill patients with COVID-19 present with typical sepsis-related clinical manifestations, including multiple organ dysfunction syndrome, coagulopathy, and septic shock. In addition, it has been demonstrated that severe COVID-19 has some pathological similarities with sepsis, such as cytokine storm, hypercoagulable state after blood balance is disrupted and neutrophil dysfunction. Considering the parallels between COVID-19 and non-SARS-CoV-2 induced sepsis (hereafter referred to as sepsis), the aim of this study was to analyze the underlying molecular mechanisms between these two diseases by bioinformatics and a systems biology approach, providing new insights into the pathogenesis of COVID-19 and the development of new treatments. Specifically, the gene expression profiles of COVID-19 and sepsis patients were obtained from the Gene Expression Omnibus (GEO) database and compared to extract common differentially expressed genes (DEGs). Subsequently, common DEGs were used to investigate the genetic links between COVID-19 and sepsis. Based on enrichment analysis of common DEGs, many pathways closely related to inflammatory response were observed, such as Cytokine-cytokine receptor interaction pathway and NF-kappa B signaling pathway. In addition, protein-protein interaction networks and gene regulatory networks of common DEGs were constructed, and the analysis results showed that ITGAM may be a potential key biomarker base on regulatory analysis. Furthermore, a disease diagnostic model and risk prediction nomogram for COVID-19 were constructed using machine learning methods. Finally, potential therapeutic agents, including progesterone and emetine, were screened through drug-protein interaction networks and molecular docking simulations. We hope to provide new strategies for future research and treatment related to COVID-19 by elucidating the pathogenesis and genetic mechanisms between COVID-19 and sepsis.

Defying convention in the time of COVID-19: Insights into the role of γδ T cells

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 is a complex disease which immune response can be more or less potent. In severe cases, patients might experience a cytokine storm that compromises their vital functions and impedes clearance of the infection. Gamma delta (γδ) T lymphocytes have a critical role initiating innate immunity and shaping adaptive immune responses, and they are recognized for their contribution to tumor surveillance, fighting infectious diseases, and autoimmunity. γδ T cells exist as both circulating T lymphocytes and as resident cells in different mucosal tissues, including the lungs and their critical role in other respiratory viral infections has been demonstrated. In the context of SARS-CoV-2 infection, γδ T cell responses are understudied. This review summarizes the findings on the antiviral role of γδ T cells in COVID-19, providing insight into how they may contribute to the control of infection in the mild/moderate clinical outcome.

Beneficial Immune Regulation by Biological Response Modifier Glucans in COVID-19 and Their Envisaged Potentials in the Management of Sepsis

Sepsis is a life-threatening condition caused by an abnormal immune response induced by infection with no approved or specific therapeutic options. We present our perspectives for the therapeutic management of sepsis through a four-way approach: (1) infection control through immune enhancement; (2) immune suppression during the initial hyper-inflammatory phase; (3) balanced immune-modulation to counter the later immune-paralysis phase; and (4) advantageous effects on metabolic and coagulation parameters throughout. COVID-19 is a virus-triggered, accelerated sepsis-like reaction that is associated with the rapid progress of an inflammatory cascade involving a cytokine storm and multiorgan failure. Here, we discuss the potential of the biological response modifiers, β-glucans (BRMGs), in the management of sepsis based on their beneficial effects on inflammatory-immune events in COVID-19 clinical studies. In COVID-19 patients, apart from metabolic regulation, BRMGs, derived from a black yeast, Aureobasidium pullulans strain AFO-202, have been reported to stimulate immune responses. BRMGs, produced by another strain (N-163) of A. pullulans, have been implicated in the beneficial regulation of inflammatory markers and immunity, namely IL-6, C-reactive protein (CRP), D-Dimer, ferritin, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-C-reactive protein ratio (LCR), leucocyte-to-C-reactive protein ratio (LeCR), and leukocyte-to-IL-6 ratio (LeIR). Agents such as these β-glucans, which are safe as they have been widely consumed by humans for decades, have potential as adjuncts for the prevention and management of sepsis as they exert their beneficial effects across the spectrum of processes and factors involved in sepsis pathology, including, but not limited to, metabolism, infection, inflammation, immune modulation, immune enhancement, and gut microbiota.

Pancreatic Stone Protein as a Biomarker for Sepsis at the Emergency Department of a Large Tertiary Hospital

Early recognition of sepsis is essential for improving outcomes and preventing complications such as organ failure, depression, and neurocognitive impairment. The emergency department (ED) plays a key role in the early identification of sepsis, but clinicians lack diagnostic tools. Potentially, biomarkers could be helpful in assisting clinicians in the ED, but no marker has yet been successfully implemented in daily practice with good clinical performance. Pancreatic stone protein (PSP) is a promising biomarker in the context of sepsis, but little is known about the diagnostic performance of PSP in the ED. We prospectively investigated the diagnostic value of PSP in such a population for patients suspected of infection. PSP was compared with currently used biomarkers, including white blood cell count (WBC) and C-reactive protein (CRP). Of the 156 patients included in this study, 74 (47.4%) were diagnosed with uncomplicated infection and 26 (16.7%) patients with sepsis, while 56 (35.9%) eventually had no infection. PSP was significantly higher for sepsis patients compared to patients with no sepsis. In multivariate regression, PSP was a significant predictor for sepsis, with an area under the curve (AUC) of 0.69. Positive and negative predictive values for this model were 100% and 84.4%, respectively. Altogether, these findings show that PSP, measured at the ED of a tertiary hospital, is associated with sepsis but lacks the diagnostic performance to be used as single marker.

HDAC Inhibition as Potential Therapeutic Strategy to Restore the Deregulated Immune Response in Severe COVID-19

The COVID-19 pandemic has had a devastating impact worldwide and has been a great challenge for the scientific community. Vaccines against SARS-CoV-2 are now efficiently lessening COVID-19 mortality, although finding a cure for this infection is still a priority. An unbalanced immune response and the uncontrolled release of proinflammatory cytokines are features of COVID-19 pathophysiology and contribute to disease progression and worsening. Histone deacetylases (HDACs) have gained interest in immunology, as they regulate the innate and adaptative immune response at different levels. Inhibitors of these enzymes have already proven therapeutic potential in cancer and are currently being investigated for the treatment of autoimmune diseases. We thus tested the effects of different HDAC inhibitors, with a focus on a selective HDAC6 inhibitor, on immune and epithelial cells in in vitro models that mimic cells activation after viral infection. Our data indicate that HDAC inhibitors reduce cytokines release by airway epithelial cells, monocytes and macrophages. This anti-inflammatory effect occurs together with the reduction of monocytes activation and T cell exhaustion and with an increase of T cell differentiation towards a T central memory phenotype. Moreover, HDAC inhibitors hinder IFN-I expression and downstream effects in both airway epithelial cells and immune cells, thus potentially counteracting the negative effects promoted in critical COVID-19 patients by the late or persistent IFN-I pathway activation. All these data suggest that an epigenetic therapeutic approach based on HDAC inhibitors represents a promising pharmacological treatment for severe COVID-19 patients.

Prognostic value of copeptin and mid-regional proadrenomedullin in COVID-19-hospitalized patients

BACKGROUND

Biomarkers are used for diagnosis, risk stratification and medical decisions. Copeptin and mid-regional proadrenomedullin (MR-proADM) are markers of stress and endothelial function, respectively, which have been studied in pneumonia, sepsis and septic shock. This study aimed to assess whether copeptin and MR-proADM could predict coronavirus disease 2019 (COVID-19) in-hospital outcomes, that is multi-system complications, length of stay and mortality.

METHODS

Copeptin and MR-proADM were assessed at admission in 116 patients hospitalized with COVID-19. Data were retrospectively extracted from an online database. The primary endpoint was in-hospital mortality. The secondary endpoints were in-hospital complications, the composite outcome 'death, or admission to intensive care unit, or in-hospital complications', and length of stay. The predictive power was expressed as area under the receiver operator characteristic curve (AUROC).

RESULTS

Copeptin was increased in non-survivors (median 29.7 [interquartile range 13.0-106.2] pmol/L) compared to survivors (10.9 [5.9-25.3] pmol/L, p < 0.01). The AUROC for mortality was 0.71, with a hazard ratio of 3.67 (p < 0.01) for copeptin values > 25.3 pmol/L. MR-proADM differentiated survivors (0.8 [0.6-1.1] nmol/L) from non-survivors (1.5 [1.1-2.8] nmol/L, p < 0.001) and yielded a AUROC of 0.79 and a hazard ratio of 7.02 (p < 0.001) for MR-proADM values > 1.0 nmol/L. Copeptin and MR-proADM predicted sepsis (AUROC 0.95 and 0.96 respectively), acute kidney injury (0.87 and 0.90), the composite outcome (0.69 and 0.75) and length of stay (r = 0.42, p < 0.001, and r = 0.46, p < 0.001).

CONCLUSIONS

Admission MR-proADM and copeptin may be implemented for early risk stratification in COVID-19-hospitalized patients to help identify those eligible for closer monitoring and care intensification.

Cardiovascular Dysfunction in COVID-19: Association Between Endothelial Cell Injury and Lactate

Coronavirus disease 2019 (COVID-19), an infectious respiratory disease propagated by a new virus known as Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has resulted in global healthcare crises. Emerging evidence from patients with COVID-19 suggests that endothelial cell damage plays a central role in COVID-19 pathogenesis and could be a major contributor to the severity and mortality of COVID-19. Like other infectious diseases, the pathogenesis of COVID-19 is closely associated with metabolic processes. Lactate, a potential biomarker in COVID-19, has recently been shown to mediate endothelial barrier dysfunction. In this review, we provide an overview of cardiovascular injuries and metabolic alterations caused by SARS-CoV-2 infection. We also propose that lactate plays a potential role in COVID-19-driven endothelial cell injury.

Role of therapeutic plasma exchange in the management of COVID-19-induced cytokine storm syndrome

The risk of mortality in patients with coronavirus disease 2019 (COVID-19) is largely related to an excessive immune response, resulting in a hyperinflammatory and hypercoagulable condition collectively referred to as cytokine storm syndrome (CSS). Management of critically ill patients with COVID-19 has included attempts to abate this process, prevent disease progression, and reduce mortality. In this context, therapeutic plasma exchange (TPE) offers an approach to eliminate inflammatory factors and cytokines, offset the pathologic coagulopathy, and reduce the CSS effects. The aim of this review is to analyze available data on the use of TPE for the treatment of CSS in patients with COVID-19. Systematic searches of PubMed, Scopus and COVID-19 Research were conducted to identify articles published between March 1, 2020 and May 26, 2021 reporting the use of TPE for the treatment of COVID-19-induced CSS. A total of 34 peer-reviewed articles (1 randomized controlled trial, 4 matched case-control series, 15 single-group case series, and 14 case reports), including 267 patients, were selected. Despite the low evidence level of the available data, TPE appeared to be a safe intervention for critically ill patients with COVID-19-induced CSS. Although inconsistencies exist between studies, they showed a general trend for decreased interleukin-6, C-reactive protein, ferritin, D-dimer, and fibrinogen levels and increased lymphocyte counts following TPE, supporting the immunomodulatory effect of this treatment. Moreover, TPE was associated with improvements in clinical outcomes in critically ill patients with COVID-19. While TPE may offer a valuable option to treat patients with COVID-19-induced CSS, high-quality randomized controlled clinical trials are needed to confirm its potential clinical benefits, feasibility, and safety. Moreover, clear criteria should be established to identify patients with CSS who might benefit from TPE.

A blood atlas of COVID-19 defines hallmarks of disease severity and specificity

Treatment of severe COVID-19 is currently limited by clinical heterogeneity and incomplete description of specific immune biomarkers. We present here a comprehensive multi-omic blood atlas for patients with varying COVID-19 severity in an integrated comparison with influenza and sepsis patients versus healthy volunteers. We identify immune signatures and correlates of host response. Hallmarks of disease severity involved cells, their inflammatory mediators and networks, including progenitor cells and specific myeloid and lymphocyte subsets, features of the immune repertoire, acute phase response, metabolism, and coagulation. Persisting immune activation involving AP-1/p38MAPK was a specific feature of COVID-19. The plasma proteome enabled sub-phenotyping into patient clusters, predictive of severity and outcome. Systems-based integrative analyses including tensor and matrix decomposition of all modalities revealed feature groupings linked with severity and specificity compared to influenza and sepsis. Our approach and blood atlas will support future drug development, clinical trial design, and personalized medicine approaches for COVID-19.

Endogenous Carboxyhemoglobin Level Variation in COVID-19 and Bacterial Sepsis: A Novel Approach?

Background: The increased production of carbon monoxide (CO) in sepsis has been proven, but the blood level variations of carboxyhemoglobin (COHb) as a potential evolutionary parameter of COVID-19 and sepsis/septic shock have yet to be determined. This study aims to evaluate the serum level variation of COHb as a potential evolutionary parameter in COVID-19 critically ill patients and in bacterial sepsis. Materials and method: A prospective and observational study was conducted on two groups of patients: the bacterial sepsis group (n = 52) and the COVID-19 group (n = 52). We followed paraclinical parameters on Day 1 (D1) and Day 5 (D5) of sepsis/ICU admission for COVID-19 patients. Results: D1 of sepsis: statistically significant positive correlations between: COHb values and serum lactate (p = 0.024, r = 0.316), and total bilirubin (p = 0.01, r = 0.359). In D5 of sepsis: a statistically significant positive correlations between: COHb values and procalcitonin (PCT) (p = 0.038, r = 0.402), and total bilirubin (p = 0.023, r = 0.319). D1 of COVID-19 group: COHb levels were statistically significantly positively correlated with C-reactive protein CRP values (p = 0.003, r = 0.407) and with PCT values (p = 0.022, r = 0.324) and statistically significantly negatively correlated with serum lactate values (p = 0.038, r = −0.285). Conclusion: COHb variation could provide rapid information about the outcome of bacterial sepsis/septic shock, having the advantages of a favorable cost-effectiveness ratio, and availability as a point-of-care test.

Platelets modulate CD4+ T Cell function in Covid-19 Through A PD-L1 Dependent Mechanism

Severe COVID-19 is associated with a systemic inflammatory response and progressive CD4⁺ T cell lymphopenia and dysfunction. We evaluated whether platelets might contribute to CD4⁺ T cell dysfunction in COVID-19. We observed a high frequency of CD4⁺ T cell-platelet aggregates in COVID-19 inpatients that inversely correlated with lymphocyte counts. Platelets from COVID-19 inpatients but not from healthy donors (HD) inhibited the up-regulation of CD25 expression and TNF-α production by CD4⁺ T cells. In addition, IFN-γ production was increased by platelets from HD but not from COVID-19 inpatients. A high expression of PD-L1 was found in platelets from COVID-19 patients to be inversely correlated with IFN-γ production by activated CD4⁺ T cells co-cultured with platelets. We also found that a PD-L1 blocking antibody significantly restored platelet-ability to stimulate IFN-γ production by CD4⁺ T cells. Our study suggests that platelets might contribute to disease progression in COVID-19 not only by promoting thrombotic and inflammatory events, but also by affecting CD4⁺ T cells functionality.

Inflammation-Induced Coagulopathy Substantially Differs Between COVID-19 and Septic Shock: A Prospective Observational Study

Critical COVID-19, like septic shock, is related to a dysregulated systemic inflammatory reaction and is associated with a high incidence of thrombosis and microthrombosis. Improving the understanding of the underlying pathophysiology of critical COVID-19 could help in finding new therapeutic targets already explored in the treatment of septic shock. The current study prospectively compared 48 patients with septic shock and 22 patients with critical COVID-19 regarding their clinical characteristics and outcomes, as well as key plasmatic soluble biomarkers of inflammation, coagulation, endothelial activation, platelet activation, and NETosis. Forty-eight patients with matched age, gender, and co-morbidities were used as controls. Critical COVID-19 patients exhibited less organ failure but a prolonged ICU length-of-stay due to a prolonged respiratory failure. Inflammatory reaction of critical COVID-19 was distinguished by very high levels of interleukin (IL)-1β and T lymphocyte activation (including IL-7 and CD40L), whereas septic shock displays higher levels of IL-6, IL-8, and a more significant elevation of myeloid response biomarkers, including Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) and IL-1ra. Subsequent inflammation-induced coagulopathy of COVID-19 also differed from sepsis-induced coagulopathy (SIC) and was characterized by a marked increase in soluble tissue factor (TF) but less platelets, antithrombin, and fibrinogen consumption, and less fibrinolysis alteration. In conclusion, COVID-19 inflammation-induced coagulopathy substantially differs from SIC. Modulating TF release and activity should be evaluated in critical COVID-19 patients.

Preclinical Evaluation of Chicken Egg Yolk Antibody (IgY) Anti-RBD Spike SARS-CoV-2—A Candidate for Passive Immunization against COVID-19

The coronavirus disease 2019 (COVID-19) has become a substantial threat to the international health sector and the global economy. As of 26 December 2021, the number of mortalities resulting from COVID-19 exceeded 5.3 million worldwide. The absence of an effective non-vaccine treatment has prompted the quest for prophylactic agents that can be used to combat COVID-19. This study presents the feasibility of chicken egg yolk antibody (IgY) anti-receptor-binding domain (RBD) spike SARS-CoV-2 as a strong candidate to neutralize the virus for application in passive immunization. For the purpose of preclinical studies, we radiolabeled IgY anti-RBD spike SARS-CoV-2 with radionuclide iodine-131. This allowed us to evaluate several biological characteristics of IgY in vitro, in vivo, and ex vivo. The preclinical data suggest that IgY anti-RBD spike SARS-CoV-2 could specifically bind to the SARS-CoV-2 antigens; however, little uptake was observed in normal cells (MRC-5) (<2%). Furthermore, the ex vivo biodistribution study revealed that IgY predominantly accumulated in the trachea of normal mice compared to other organs. We also found that IgY possessed a good safety profile when used as an intranasal agent. Taken together, we propose that IgY anti-RBD spike SARS-CoV-2 has the potential for application in passive immunization against COVID-19.

Impact of sepsis education for healthcare professionals and students on learner and patient outcomes: A systematic review

BACKGROUND

Sepsis is an important global healthcare problem that is a key challenge faced by healthcare professionals face worldwide. One key effort aimed at reducing the global burden of sepsis is educating healthcare professionals about early identification and management of sepsis.

AIM

To provide a comprehensive evaluation of sepsis education among healthcare professionals and students.

METHODS

Six databases (PubMed, CINAHL, Embase, MEDLINE, Cochrane Central Register of Controlled Trials, and Scopus) were searched. We included studies that described and evaluated any form of education or training on sepsis delivered to healthcare professionals and students. Study outcomes were summarised according to the adapted Kirkpatrick model of training evaluation.

RESULTS

Thirty-two studies were included in the review. The learning contents were reported to be in accordance with the Surviving Sepsis Campaign guidelines. Seven studies included the topic of interprofessional teamwork and communication in their sepsis education content. Most educational programs were effective and reported positive effects on immediate knowledge outcomes. Interventions that were delivered through an active learning approach such as simulation and game-based learning generally produced greater gains than didactic teaching. Improvements in patient care processes and patient outcomes were associated with the concomitant existence or implementation of a hospital sepsis care bundle.

CONCLUSION

Incorporating active learning strategies into sepsis education interventions has the potential to improve learners' long-term outcomes. In addition, sepsis education and protocol-based sepsis care bundle act in synergy to augment greater improvements in care processes and patient benefits.

Monocyte distribution width as a novel sepsis indicator in COVID-19 patients

BACKGROUND

The severe acute respiratory syndrome coronavirus (SARS-CoV-2) is a highly transmittable virus which causes the novel coronavirus disease (COVID-19). Monocyte distribution width (MDW) is an in-vitro hematological parameter which describes the changes in monocyte size distribution and can indicate progression from localized infection to systemic infection. In this study we evaluated the correlation between the laboratory parameters and available clinical data in different quartiles of MDW to predict the progression and severity of COVID-19 infection.

METHODS

A retrospective analysis of clinical data collected in the Emergency Department of Rashid Hospital Trauma Center-DHA from adult individuals tested for SARS-CoV-2 between January and June 2020. The patients (n = 2454) were assigned into quartiles based on their MDW value on admission. The four groups were analyzed to determine if MDW was an indicator to identify patients who are at increased risk for progression to sepsis.

RESULTS

Our data showed a significant positive correlation between MDW and various laboratory parameters associated with SARS-CoV-2 infection. The study also revealed that MDW ≥ 24.685 has a strong correlation with poor prognosis of COVID-19.

CONCLUSIONS

Monitoring of monocytes provides a window into the systemic inflammation caused by infection and can aid in evaluating the progression and severity of COVID-19 infection.

COVID-19 and Panax ginseng: Targeting platelet aggregation, thrombosis and the coagulation pathway

Coronavirus disease 2019 (COVID-19) not only targets the respiratory system but also triggers a cytokine storm and a series of complications, such as gastrointestinal problems, acute kidney injury, and myocardial ischemia. The use of natural products has been utilized to ease the symptoms of COVID-19, and in some cases, to strengthen the immune system against COVID-19. Natural products are readily available and have been regularly consumed for various health benefits. COVID-19 has been reported to be associated with the risk of thromboembolism and deep vein thrombosis. These thrombotic complications often affects mortality and morbidity. Panax ginseng, which has been widely consumed for its various health benefits has also been reported for its therapeutic effects against cardiovascular disease, thrombosis and platelet aggregation. In this review, we propose that P. ginseng can be consumed as a supplementation against the various associated complications of COVID-19, especially against thrombosis. We utilized the network pharmacology approach to validate the potential therapeutic properties of P. ginseng against COVID-19 mediated thrombosis, the coagulation pathway and platelet aggregation. Additionally, we aimed to investigate the roles of P. ginseng against COVID-19 with the involvement of platelet-leukocyte aggregates in relation to immunity-related responses in COVID-19.

Nitric Oxide: The Missing Factor in COVID-19 Severity?

Coronavirus disease 2019 (COVID-19) is a contagious respiratory and vascular disease that continues to spread among people around the world, mutating into new strains with increased transmission rates, such as the delta variant. The scientific community is struggling to discover the link between negative COVID-19 outcomes in patients with preexisting conditions, as well as identify the cause of the negative clinical patient outcomes (patients who need medical attention, including hospitalization) in what seems like a widespread range of COVID-19 symptoms that manifest atypically to any preexisting respiratory tract infectious diseases known so far. Having successfully developed a nutritional formulation intervention based on nitrate, a nitric oxide precursor, the authors hypothesis is that both the comorbidities associated with negative clinical patient outcomes and symptoms associated with COVID-19 sickness are linked to the depletion of a simple molecule: nitric oxide.

Comparison of outcome and characteristics between 6343 COVID-19 patients and 2256 other community-acquired viral pneumonia patients admitted to Dutch ICUs

Purpose

Describe the differences in characteristics and outcomes between COVID-19 and other viral pneumonia patients admitted to Dutch ICUs.

Materials and methods

Data from the National-Intensive-Care-Evaluation-registry of COVID-19 patients admitted between February 15th and January 1th 2021 and other viral pneumonia patients admitted between January 1st 2017 and January 1st 2020 were used. Patients' characteristics, the unadjusted, and adjusted in-hospital mortality were compared.

Results

6343 COVID-19 and 2256 other viral pneumonia patients from 79 ICUs were included. The COVID-19 patients included more male (71.3 vs 49.8%), had a higher Body-Mass-Index (28.1 vs 25.5), less comorbidities (42.2 vs 72.7%), and a prolonged hospital length of stay (19 vs 9 days). The COVID-19 patients had a significantly higher crude in-hospital mortality rate (Odds ratio (OR) = 1.80), after adjustment for patient characteristics and ICU occupancy rate the OR was respectively 3.62 and 3.58.

Conclusion

Higher mortality among COVID-19 patients could not be explained by patient characteristics and higher ICU occupancy rates, indicating that COVID-19 is more severe compared to other viral pneumonia. Our findings confirm earlier warnings of a high need of ICU capacity and high mortality rates among relatively healthy COVID-19 patients as this may lead to a higher mental workload for the staff.