Respiratory viral sepsis: epidemiology, pathophysiology, diagnosis and treatment

Mesenchymal stem cell-conditioned medium prevents inflammation-induced liver and lung damage in septic mice

AIM

Sepsis is a life-threatening condition caused by a dysregulated immune response to infection. Broad-spectrum antibiotics are used to treat it. However, due to antibiotic resistance, alternative treatments are needed. Mesenchymal stem cells (MSCs) have become a promising therapeutic tool for sepsis due to their immunomodulatory properties. The limitations of MSC therapy have led to increased attention to cell derivatives such as conditioned medium (CM). This study investigates the immunomodulatory effects of young and old MSC-CM during the inflammatory phase of sepsis.

MAIN METHODS

The cecal ligation and puncture (CLP) model was used to induce sepsis in mice. The mice were divided into four groups: sham, CLP, CLP treated with young MSC-CM, and CLP treated with old MSC-CM. The CM was injected intraperitoneally at 2-, 12-, and 24-hours post-surgery. After 72 h, blood was collected and white blood cells (WBCs) were counted. In addition, serum and tissue were isolated, and the levels of alanine transaminase (ALT) and aspartate transaminase (AST) in serum, bacterial load in the spleen, concentration of pro- and anti-inflammatory cytokines, and histopathology of liver and lung were investigated.

KEY FINDINGS

MSC-CM decreased serum AST and ALT levels, bacterial load in the spleen, and pro-inflammatory cytokines in serum. In addition, tissue damage was reduced, and the survival rate and WBC count increased. There was no significant difference between the young and old MSC-CM.

SIGNIFICANCE

MSC-CM effectively reduced inflammation-induced tissue damage in the liver and lungs during sepsis. Although young MSC-CM had better immunomodulatory effects than old MSC-CM, the difference was not significant.

Structure-Based Drug Design of ADRA2A Antagonists Derived from Yohimbine

Yohimbine, a natural indole alkaloid and a nonselective adrenoceptor antagonist, possesses potential benefits in treating inflammatory disorders and sepsis. Nevertheless, its broader clinical use faces challenges due to its low receptor selectivity. A structure-activity relationship study of novel yohimbine analogues identified amino esters of yohimbic acid as potent and selective ADRA2A antagonists. Specifically, amino ester 4n, in comparison to yohimbine, showed a 6-fold higher ADRA1A/ADRA2A selectivity index (SI > 556 for 4n) and a 25-fold higher ADRA2B/ADRA2A selectivity index. Compound 4n also demonstrated high plasma and microsomal stability, moderate-to-low membrane permeability determining its limited ability to cross the blood-brain barrier, and negligible toxicity on nontumor normal human dermal fibroblasts. Compound 4n represents an important complementary pharmacological tool to study the involvement of adrenoceptor subtypes in pathophysiologic conditions such as inflammation and sepsis and a novel candidate for further preclinical development to treat ADRA2A-mediated pathologies.

Sulfur Dioxide Alleviates Organ Damage and Inflammatory Response in Cecal Ligation and Puncture-Induced Sepsis Rat

The study aimed to elucidate the mechanisms by which sulfur dioxide (SO2) alleviates organ damage during sepsis using RNA-Seq technology. A cecal ligation and puncture (CLP) sepsis model was established in rats, and the effects of SO2 treatment on organ damage were assessed through histopathological examinations. RNA-Seq was performed to analyze differentially expressed genes (DEGs), and subsequent functional annotations and enrichment analyses were conducted. The CLP model successfully induced sepsis symptoms in rats. Histopathological evaluation revealed that SO2 treatment considerably reduced tissue damage across the heart, kidney, liver, and lungs. RNA-Seq identified 950 DEGs between treated and untreated groups, with significant enrichment in genes associated with ribosomal and translational activities, amino acid metabolism, and PI3K-Akt signaling. Furthermore, gene set enrichment analysis (GSEA) showcased enrichments in pathways related to transcriptional regulation, cellular migration, proliferation, and calcium-ion binding. In conclusion, SO2 effectively mitigates multi-organ damage induced by CLP sepsis, potentially through modulating gene expression patterns related to critical biological processes and signaling pathways. These findings highlight the therapeutic promise of SO2 in managing sepsis-induced organ damage.

Mechanisms of Sepsis-Induced Acute Lung Injury and Advancements of Natural Small Molecules in Its Treatment

Sepsis-induced acute lung injury (ALI), characterized by widespread lung dysfunction, is associated with significant morbidity and mortality due to the lack of effective pharmacological treatments available clinically. Small-molecule compounds derived from natural products represent an innovative source and have demonstrated therapeutic potential against sepsis-induced ALI. These natural small molecules may provide a promising alternative treatment option for sepsis-induced ALI. This review aims to summarize the pathogenesis of sepsis and potential therapeutic targets. It assembles critical updates (from 2014 to 2024) on natural small molecules with therapeutic potential against sepsis-induced ALI, detailing their sources, structures, effects, and mechanisms of action.

Respiratory tract viral infections associated sepsis in patients with underlying liver disease: Viral sepsis an entity to look forward!

BACKGROUND

Sepsis remains a global health burden associated with significant morbidity and mortality. Bacteria are known to be the predominant pathogens in sepsis; however, viral etiologies in sepsis are still under diagnosed. Respiratory viral pathogens have been previously linked to sepsis, but the knowledge of incidence, disease burden and mortality of viral-induced sepsis remains limited. This study aimed at understanding the role of respiratory viral infections in the causation of sepsis in liver disease patients.

METHODS

In this retrospective study, the clinical records of liver disease patients with influenza-like illness, whose requests for respiratory viral testing were received from January 2019 to December 2022, were reviewed. Respiratory viruses were identified using FilmArray 2.0 respiratory panel (BioFire Diagnostics, Utah, USA).

RESULTS

Of 1391 patients tested, a respiratory viral etiology was detected in 23%. The occurrence of sepsis was seen in 35%. Among these, isolated viral etiology with no other bacterial/fungal coinfection was found in 55% of patients. Rhinovirus/Enterovirus was found as the most common underlying viral etiology (23.4%). The sepsis prevalence was higher among patients with associated comorbidities (45%) and decompensated cirrhosis (84%). On multi-variable analysis, no factor was found independently associated with sepsis-related mortality.

CONCLUSION

This study underlines the importance of isolated viral etiology in causation of sepsis among liver disease patients. Patients with comorbidities, older age and decompensated cirrhosis are at an increased risk of developing sepsis and are associated with poorer outcomes. Accurate and timely identification of the viral etiology in sepsis would prevent the misuse of antibiotics and improve overall patient care.

Developments and Trends of Nanotechnology Application in Sepsis: A Comprehensive Review Based on Knowledge Visualization Analysis

Sepsis, a common life-threatening clinical condition, continues to have high morbidity and mortality rates, despite advancements in management. In response, significant research efforts have been directed toward developing effective strategies. Within this scope, nanotechnology has emerged as a particularly promising field, attracting significant interest for its potential to enhance disease diagnosis and treatment. While several reviews have highlighted the use of nanoparticles in sepsis, comprehensive studies that summarize and analyze the hotspots and research trends are lacking. To identify and further promote the development of nanotechnology in sepsis, a bibliometric analysis was conducted on the relevant literature, assessing research trends and hotspots in the application of nanomaterials for sepsis. Next, a comprehensive review of the subjectively recognized research hotspots in sepsis, including nanotechnology-enhanced biosensors and nanoscale imaging for sepsis diagnostics, and nanoplatforms designed for antimicrobial, immunomodulatory, and detoxification strategies in sepsis therapy, is elucidated, while the potential side effects and toxicity risks of these nanomaterials were discussed. Particular attention is given to biomimetic nanoparticles, which mimic the biological functions of source cells like erythrocytes, immune cells, and platelets to evade immune responses and effectively deliver therapeutic agents, demonstrating substantial translational potential. Finally, current challenges and future perspectives of nanotechnology applications in sepsis with a view to maximizing their great potential in the research of translational medicine are also discussed.

Advances in sepsis biomarkers

Sepsis, a dysregulated host immune response to an infectious agent, significantly increases morbidity and mortality for hospitalized patients worldwide. This chapter reviews (1) the basic principles of infectious diseases, pathophysiology and current definition of sepsis, (2) established sepsis biomarkers such lactate, procalcitonin and C-reactive protein, (3) novel, newly regulatory-cleared/approved biomarkers, such as assays that evaluate white blood cell properties and immune response molecules, and (4) emerging biomarkers and biomarker panels to highlight future directions and opportunities in the diagnosis and management of sepsis.

Identification and analysis of genes associated with the severity and prognosis of sepsis

BACKGROUND

With rapid progression, severe illness and high fatality rate, sepsis has become an acute and critical condition that seriously threatens human life and health.

OBJECTIVE

To detect miR-210 and miR-494 expression in patients with sepsis and their relationship with severity and prognosis.

METHODS

A total of 165 sepsis patients participated, including 105 patients with septic non-shock and 60 patients with septic shock. 53 sepsis patients died in 28 days, and 112 patients survived. The clinical information of all sepsis patients was retrospectively searched and reviewed. Based on the status of 28-day survival, they were categorized into survival group and death group. The expression levels in each group were compared on the first, third and seventh day. The ROC curve was applied to know the expression level of plasma miR-210 and miR-494 to predict the death.

RESULTS

The two miRNAs expression of the septic shock group were significantly higher than that in sepsis non-shock group on the first, third and seventh day (all were P< 0.05). The ROC curve found that the AUC combined to predict the death on the third day was the largest, which was 0.925 (95%CI: 0.864-0.983). The sensitivity and specificity were 94.6% and 86.3%, respectively.

CONCLUSION

The increased expression levels of plasma miR-210 and miR-494 are closely relevant to the severity and prognosis of sepsis patients. Combining the two items on the third day can predict the death of sepsis patients.

Lipid oxidation dysregulation: an emerging player in the pathophysiology of sepsis

Sepsis is a life-threatening organ dysfunction caused by abnormal host response to infection. Millions of people are affected annually worldwide. Derangement of the inflammatory response is crucial in sepsis pathogenesis. However, metabolic, coagulation, and thermoregulatory alterations also occur in patients with sepsis. Fatty acid mobilization and oxidation changes may assume the role of a protagonist in sepsis pathogenesis. Lipid oxidation and free fatty acids (FFAs) are potentially valuable markers for sepsis diagnosis and prognosis. Herein, we discuss inflammatory and metabolic dysfunction during sepsis, focusing on fatty acid oxidation (FAO) alterations in the liver and muscle (skeletal and cardiac) and their implications in sepsis development.

Point-of-Care Ultrasound: A Multimodal Tool for the Management of Sepsis in the Emergency Department

Sepsis and septic shock are life-threatening emergencies associated with increased morbidity and mortality. Hence, early diagnosis and management of both conditions is of paramount importance. Point-of-care ultrasound (POCUS) is a cost-effective and safe imaging modality performed at the bedside, which has rapidly emerged as an excellent multimodal tool and has been gradually incorporated as an adjunct to physical examination in order to facilitate evaluation, diagnosis and management. In sepsis, POCUS can assist in the evaluation of undifferentiated sepsis, while, in cases of shock, it can contribute to the differential diagnosis of other types of shock, thus facilitating the decision-making process. Other potential benefits of POCUS include prompt identification and control of the source of infection, as well as close haemodynamic and treatment monitoring. The aim of this review is to determine and highlight the role of POCUS in the evaluation, diagnosis, treatment and monitoring of the septic patient. Future research should focus on developing and implementing a well-defined algorithmic approach for the POCUS-guided management of sepsis in the emergency department setting given its unequivocal utility as a multimodal tool for the overall evaluation and management of the septic patient.

Association of Molnupiravir and Nirmatrelvir-Ritonavir with reduced mortality and sepsis in hospitalized omicron patients: a territory-wide study

This study evaluates the association between antivirals (Molnupiravir and Nirmatrelvir-Ritonavir) and all-cause and respiratory mortality and organ dysfunction among high-risk COVID-19 patients during an Omicron outbreak. Two cohorts, Nirmatrelvir-Ritonavir versus control and Molnupiravir versus control, were constructed with inverse probability treatment weighting to balance baseline characteristics. Cox proportional hazards models evaluated the association of their use with all-cause mortality, respiratory mortality, and all-cause sepsis (a composite of circulatory shock, respiratory failure, acute liver injury, coagulopathy, and acute liver impairment). Patients recruited were hospitalized and diagnosed with the COVID-19 Omicron variant between February 22, 2022 and April 15, 2022, and followed up until May 15, 2022. The study included 17,704 patients. There were 4.67 and 22.7 total mortalities per 1000 person-days in the Nirmatrelvir-Ritonavir and control groups respectively before adjustment (weighted incidence rate ratio, - 18.1 [95% CI - 23.0 to - 13.2]; hazard ratio, 0.18 [95% CI, 0.11-0.29]). There were 6.64 and 25.9 total mortalities per 1000 person-days in the Molnupiravir and control groups respectively before adjustment (weighted incidence rate ratio per 1000 person-days, - 19.3 [95% CI - 22.6 to - 15.9]; hazard ratio, 0.23 [95% CI 0.18-0.30]). In all-cause sepsis, there were 13.7 and 35.4 organ dysfunction events per 1000 person-days in the Nirmatrelvir-Ritonavir and control groups respectively before adjustment (weighted incidence rate ratio per 1000 person-days, - 21.7 [95% CI - 26.3 to - 17.1]; hazard ratio, 0.44 [95% CI 0.38-0.52]). There were 23.7 and 40.8 organ dysfunction events in the Molnupiravir and control groups respectively before adjustment (weighted incidence ratio per 1000 person-days, - 17.1 [95% CI, - 20.6 to - 13.6]; hazard ratio, 0.63 [95% CI 0.58-0.69]). Among COVID-19 hospitalized patients, use of either Nirmatrelvir-Ritonavir or Molnupiravir compared with no antiviral use was associated with a significantly lower incidence of 28-days all-cause and respiratory mortality and sepsis.

Mortality and Sequential Organ Failure Assessment Score in Patients With Suspected Sepsis: The Impact of Acute and Preexisting Organ Failures and Infection Likelihood

The Sequential Organ Failure Assessment (SOFA) was chosen in the definition of sepsis due to superior validity in predicting mortality. However, few studies have assessed the contributions of acute versus chronic organ failures to SOFA for mortality prediction.

OBJECTIVES

The main objective in this study was to assess the relative importance of chronic and acute organ failures in mortality prediction in patients with suspected sepsis at hospital admission. We also evaluated how the presence of infection influenced the ability of SOFA to predict 30-day mortality.

DESIGN SETTING AND PARTICIPANTS

Single-center prospective cohort study including 1,313 adult patients with suspected sepsis in rapid response teams in the emergency department.

MAIN OUTCOMES AND MEASURES

The main outcome was 30-day mortality. We measured the maximum total SOFA score during admission (SOFATotal), whereas preexisting chronic organ failure SOFA (SOFAChronic) score was assessed by chart review, allowing calculation of the corresponding acute SOFA (SOFAAcute) score. Likelihood of infection was determined post hoc as "No infection" or "Infection."

RESULTS

SOFAAcute and SOFAChronic were both associated with 30-day mortality, adjusted for age and sex (adjusted odds ratios [AORs], 1.3; 95% CI, 1.3-14 and 1.3; 1.2-1.7), respectively. Presence of infection was associated with lower 30-day mortality (AOR, 0.4; 95% CI, 0.2-0.6), even when corrected for SOFA. In "No infection" patients, SOFAAcute was not associated with mortality (AOR, 1.1; 95% CI, 1.0-1.2), and in this subgroup, neither SOFAAcute greater than or equal to 2 (relative risk [RR], 1.1; 95% CI, 0.6-1.8) nor SOFATotal greater than or equal to 2 (RR, 3.6; 95% CI, 0.9-14.1) was associated with higher mortality.

CONCLUSIONS AND RELEVANCE

Chronic and acute organ failures were equally associated with 30-day mortality in suspected sepsis. A substantial part of the total SOFA score was due to chronic organ failure, calling for caution when using total SOFA in defining sepsis and as an outcome in intervention studies. SOFA's mortality prediction ability was highly dependent on actual presence of infection.

Evaluation of the host immune response assay SeptiCyte RAPID for potential triage of COVID-19 patients

Tools for the evaluation of COVID-19 severity would help clinicians with triage decisions, especially the decision whether to admit to ICU. The aim of this study was to evaluate SeptiCyte RAPID, a host immune response assay (Immunexpress, Seattle USA) as a triaging tool for COVID-19 patients requiring hospitalization and potentially ICU care. SeptiCyte RAPID employs a host gene expression signature consisting of the ratio of expression levels of two immune related mRNAs, PLA2G7 and PLAC8, measured from whole blood samples. Blood samples from 146 adult SARS-CoV-2 (+) patients were collected within 48 h of hospital admission in PAXgene blood RNA tubes at Hospital del Mar, Barcelona, Spain, between July 28th and December 1st, 2020. Data on demographics, vital signs, clinical chemistry parameters, radiology, interventions, and SeptiCyte RAPID were collected and analyzed with bioinformatics methods. The performance of SeptiCyte RAPID for COVID-19 severity assessment and ICU admission was evaluated, relative to the comparator of retrospective clinical assessment by the Hospital del Mar clinical care team. In conclusion, SeptiCyte RAPID was able to stratify COVID-19 cases according to clinical severity: critical vs. mild (AUC = 0.93, p < 0.0001), critical vs. moderate (AUC = 0.77, p = 0.002), severe vs. mild (AUC = 0.85, p = 0.0003), severe vs. moderate (AUC = 0.63, p = 0.05). This discrimination was significantly better (by AUC or p-value) than could be achieved by CRP, lactate, creatine, IL-6, or D-dimer. Some of the critical or severe cases had "early" blood draws (before ICU admission; n = 33). For these cases, when compared to moderate and mild cases not in ICU (n = 37), SeptiCyte RAPID had AUC = 0.78 (p = 0.00012). In conclusion, SeptiCyte RAPID was able to stratify COVID-19 cases according to clinical severity as defined by the WHO COVID-19 Clinical Management Living Guidance of January 25th, 2021. Measurements taken early (before a patient is considered for ICU admission) suggest that high SeptiScores could aid in predicting the need for later ICU admission.

Recombinant GM-CSF for diseases of GM-CSF insufficiency: Correcting dysfunctional mononuclear phagocyte disorders

Introduction

Endogenous granulocyte-macrophage colony-stimulating factor (GM-CSF), identified by its ability to support differentiation of hematopoietic cells into several types of myeloid cells, is now known to support maturation and maintain the metabolic capacity of mononuclear phagocytes including monocytes, macrophages, and dendritic cells. These cells sense and attack potential pathogens, present antigens to adaptive immune cells, and recruit other immune cells. Recombinant human (rhu) GM-CSF (e.g., sargramostim [glycosylated, yeast-derived rhu GM-CSF]) has immune modulating properties and can restore the normal function of mononuclear phagocytes rendered dysfunctional by deficient or insufficient endogenous GM-CSF.

Methods

We reviewed the emerging biologic and cellular effects of GM-CSF. Experts in clinical disease areas caused by deficient or insufficient endogenous GM-CSF examined the role of GM-CSF in mononuclear phagocyte disorders including autoimmune pulmonary alveolar proteinosis (aPAP), diverse infections (including COVID-19), wound healing, and anti-cancer immune checkpoint inhibitor therapy.

Results

We discuss emerging data for GM-CSF biology including the positive effects on mitochondrial function and cell metabolism, augmentation of phagocytosis and efferocytosis, and immune cell modulation. We further address how giving exogenous rhu GM-CSF may control or treat mononuclear phagocyte dysfunction disorders caused or exacerbated by GM-CSF deficiency or insufficiency. We discuss how rhu GM-CSF may augment the anti-cancer effects of immune checkpoint inhibitor immunotherapy as well as ameliorate immune-related adverse events.

Discussion

We identify research gaps, opportunities, and the concept that rhu GM-CSF, by supporting and restoring the metabolic capacity and function of mononuclear phagocytes, can have significant therapeutic effects. rhu GM-CSF (e.g., sargramostim) might ameliorate multiple diseases of GM-CSF deficiency or insufficiency and address a high unmet medical need.

[Pathophysiology of sepsis]

Up to now, sepsis is one of the most threatening diseases and its therapy remains challenging. Sepsis is currently defined as a severely dysregulated immune response to an infection resulting in organ dysfunction. The pathophysiology is mainly driven by exogenous PAMPs ("pathogen-associated molecular patterns") and endogenous DAMPs ("damage-associated molecular patterns"), which can activate PRRs ("pattern recognition receptors") on different cell types (mainly immune cells), leading to the initiation of manifold downstream pathways and a perpetuation of patients' immune response. Sepsis is neither an exclusive pro- nor an anti-inflammatory disease: both processes take place in parallel, resulting in an individual immunologic disease state depending on the severity of each component at different time points. Septic shock is a complex disorder of the macro- and microcirculation, provoking a severe lack of oxygenation further aggravating sepsis defining organ dysfunctions. An in-depth knowledge of the heterogeneity and the time-dependency of the septic immunopathology will be essential for the design of future sepsis trials and therapy planning in patients with sepsis. The big aim is to achieve a more individualized treatment strategy in patients suffering from sepsis or septic shock.

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.

Downregulation of the Protein C Signaling System Is Associated with COVID-19 Hypercoagulability-A Single-Cell Transcriptomics Analysis

Because of the interface between coagulation and the immune response, it is expected that COVID-19-associated coagulopathy occurs via activated protein C signaling. The objective was to explore putative changes in the expression of the protein C signaling network in the liver, peripheral blood mononuclear cells, and nasal epithelium of patients with COVID-19. Single-cell RNA-sequencing data from patients with COVID-19 and healthy subjects were obtained from the COVID-19 Cell Atlas database. A functional protein-protein interaction network was constructed for the protein C gene. Patients with COVID-19 showed downregulation of protein C and components of the downstream protein C signaling cascade. The percentage of hepatocytes expressing protein C was lower. Part of the liver cell clusters expressing protein C presented increased expression of ACE2. In PBMC, there was increased ACE2, inflammatory, and pro-coagulation transcripts. In the nasal epithelium, PROC, ACE2, and PROS1 were expressed by the ciliated cell cluster, revealing co-expression of ACE-2 with transcripts encoding proteins belonging to the coagulation and immune system interface. Finally, there was upregulation of coagulation factor 3 transcript in the liver and PBMC. Protein C could play a mechanistic role in the hypercoagulability syndrome affecting patients with severe COVID-19.

The burden of viral infections in pediatric intensive care unit between endemic and pandemic coronavirus infections: A tertiary care center experience

Objectives

To measure the prevalence of viral infections, length of stay (LOS), and outcome in children admitted to the pediatric intensive care unit (PICU) during the period preceding the COVID-19 pandemic in a MERS-CoV endemic country.

Methods

A retrospective chart review of children 0–14 years old admitted to PICU with a viral infection.

Results

Of 1736 patients, 164 patients (9.45%) had a positive viral infection. The annual prevalence trended downward over a three-year period, from 11.7% to 7.3%. The median PICU LOS was 11.6 days. Viral infections were responsible for 1904.4 (21.94%) PICU patient-days. Mechanical ventilation was used in 91.5% of patients, including noninvasive and invasive modes. Comorbidities were significantly associated with intubation (P-value = 0.025). Patients infected with multiple viruses had median pediatric index of mortality 2 (PIM 2) scores of 4, as compared to 1 for patients with single virus infections (p < 0.001), and a median PICU LOS of 12 days, compared to 4 in the single-virus group (p < 0.001). Overall, mortality associated with viral infections in PICU was 7 (4.3%). Patients with viral infections having multiple organ failure were significantly more likely to die in the PICU (p = 0.001).

Conclusion

Viral infections are responsible for one-fifth of PICU patient-days, with a high demand for mechanical ventilation. Patients with multiple viral infections had longer LOS, and higher PIM 2 scores. The downward trend in the yearly rate of PICU admissions for viral infections between the end of the MERS-CoV outbreak and the start of the COVID-19 pandemic may suggest viral interference that warrants further investigations.

Neutrophil Extracellular Traps, Sepsis and COVID-19 - A Tripod Stand

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current coronavirus disease 2019 (COVID-19) pandemic. Majority of COVID-19 patients have mild disease but about 20% of COVID-19 patients progress to severe disease. These patients end up in the intensive care unit (ICU) with clinical manifestations of acute respiratory distress syndrome (ARDS) and sepsis. The formation of neutrophil extracellular traps (NETs) has also been associated with severe COVID-19. Understanding of the immunopathology of COVID-19 is critical for the development of effective therapeutics. In this article, we discuss evidence indicating that severe COVID-19 has clinical presentations consistent with the definitions of viral sepsis. We highlight the role of neutrophils and NETs formation in the pathogenesis of severe COVID-19. Finally, we highlight the potential of therapies inhibiting NETs formation for the treatment of COVID-19.

Chasing the Ghost: Hyperinflammation Does Not Cause Sepsis

Sepsis is infection sufficient to cause illness in the infected host, and more severe forms of sepsis can result in organ malfunction or death. Severe forms of Coronavirus disease-2019 (COVID-19), or disease following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are examples of sepsis. Following infection, sepsis is thought to result from excessive inflammation generated in the infected host, also referred to as a cytokine storm. Sepsis can result in organ malfunction or death. Since COVID-19 is an example of sepsis, the hyperinflammation concept has influenced scientific investigation and treatment approaches to COVID-19. However, decades of laboratory study and more than 100 clinical trials designed to quell inflammation have failed to reduce sepsis mortality. We examine theoretical support underlying widespread belief that hyperinflammation or cytokine storm causes sepsis. Our analysis shows substantial weakness of the hyperinflammation approach to sepsis that includes conceptual confusion and failure to establish a cause-and-effect relationship between hyperinflammation and sepsis. We conclude that anti-inflammation approaches to sepsis therapy have little chance of future success. Therefore, anti-inflammation approaches to treat COVID-19 are likewise at high risk for failure. We find persistence of the cytokine storm concept in sepsis perplexing. Although treatment approaches based on the hyperinflammation concept of pathogenesis have failed, the concept has shown remarkable resilience and appears to be unfalsifiable. An approach to understanding this resilience is to consider the hyperinflammation or cytokine storm concept an example of a scientific paradigm. Thomas Kuhn developed the idea that paradigms generate rules of investigation that both shape and restrict scientific progress. Intrinsic features of scientific paradigms include resistance to falsification in the face of contradictory data and inability of experimentation to generate alternatives to a failing paradigm. We call for rejection of the concept that hyperinflammation or cytokine storm causes sepsis. Using the hyperinflammation or cytokine storm paradigm to guide COVID-19 treatments is likewise unlikely to provide progress. Resources should be redirected to more promising avenues of investigation and treatment.

Polarization of Microglia and Its Therapeutic Potential in Sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, leaving the inflammation process without a proper resolution, leading to tissue damage and possibly sequelae. The central nervous system (CNS) is one of the first regions affected by the peripheral inflammation caused by sepsis, exposing the neurons to an environment of oxidative stress, triggering neuronal dysfunction and apoptosis. Sepsis-associated encephalopathy (SAE) is the most frequent sepsis-associated organ dysfunction, with symptoms such as deliriums, seizures, and coma, linked to increased mortality, morbidity, and cognitive disability. However, the current therapy does not avoid those patients’ symptoms, evidencing the search for a more optimal approach. Herein we focus on microglia as a prominent therapeutic target due to its multiple functions maintaining CNS homeostasis and its polarizing capabilities, stimulating and resolving neuroinflammation depending on the stimuli. Microglia polarization is a target of multiple studies involving nerve cell preservation in diseases caused or aggravated by neuroinflammation, but in sepsis, its therapeutic potential is overlooked. We highlight the peroxisome proliferator-activated receptor gamma (PPARγ) neuroprotective properties, its role in microglia polarization and inflammation resolution, and the interaction with nuclear factor-κB (NF-κB) and mitogen-activated kinases (MAPK), making PPARγ a molecular target for sepsis-related studies to come.

Inhibition of lung microbiota-derived proapoptotic peptides ameliorates acute exacerbation of pulmonary fibrosis

Idiopathic pulmonary fibrosis is an incurable disease of unknown etiology. Acute exacerbation of idiopathic pulmonary fibrosis is associated with high mortality. Excessive apoptosis of lung epithelial cells occurs in pulmonary fibrosis acute exacerbation. We recently identified corisin, a proapoptotic peptide that triggers acute exacerbation of pulmonary fibrosis. Here, we provide insights into the mechanism underlying the processing and release of corisin. Furthermore, we demonstrate that an anticorisin monoclonal antibody ameliorates lung fibrosis by significantly inhibiting acute exacerbation in the human transforming growth factorβ1 model and acute lung injury in the bleomycin model. By investigating the impact of the anticorisin monoclonal antibody in a general model of acute lung injury, we further unravel the potential of corisin to impact such diseases. These results underscore the role of corisin in the pathogenesis of acute exacerbation of pulmonary fibrosis and acute lung injury and provide a novel approach to treating this incurable disease.

What is pneumonia?

The diagnosis of pneumonia is both simple and complex. Recent research is challenging our concept of pneumonia and radiological gold standards that have underpinned research for decades. In particular, the accuracy of chest radiographs in diagnosing pneumonia is now highly questionable when compared with computed tomography scans. Depending on the question being asked, pneumonia can be defined in clinical, pathological, radiological, or microbiological contexts, or frequently a combination of all of these. However, while the field is changing, until we have new studies defining pneumonia in new ways, clinicians can be reassured that existing guidelines based on “old” standards remain as valid as they have always been.

Recent research has challenged our concept of pneumonia. New studies will define pneumonia in new ways, but clinicians can be reassured that existing guidelines based on “old” standards remain valid.https://bit.ly/3kJiV2N

Management skin manifestation of multisystem inflammatory syndrome associated with SARS-CoV-2

BACKGROUND

Multisystem inflammatory syndrome (MIS), which develops after a past covid-19 infection. MIS can be described in different tissue inflammation, including the heart, lung, kidney, brain, skin, eye, and or gastrointestinal organs at the presence of COVID-19. Initially, MIS was described in Europe in children infected with SARS-CoV-2, then it was recently seen in the USA in 2020. MIS is a rare but serious disease condition associated with COVID-19 that can affect children (MIS-C) and adults (MIS-A).

CASE PRESENTATION

A 44-year-old male who showed MIS-A in 59-day after his first covid-19 contact history. The patient presented to our emergency department with complaints of high fever, nausea, weakness, redness of the eyes, headache, and joint pain. On the second day of his hospitalization, a maculopapular skin lesion was seen in most of the skin. His fever could not be controlled even given paracetamol and broad effective antibiotics. His clinical, radiological, and laboratory findings showed that he had MIS-A. The patient was given intravenous pulse methylprednisolone and intravenous immunoglobulin (IVIG). These treatments, then, resulted in improvement of his clinical conditions, including fever and skin lesions, on the second day of the treatment. The patient was discharged in 14 days after the treatment.

CONCLUSION

This report indicated that diagnosis and treatment of MIS-A could result in reducing patient morbidity and mortality.

COVID-19 and Sepsis

The COVID-19 pandemic has created a major alteration in the medical literature including the sepsis discussion. From the outset of the pandemic, various reports have indicated that although there are some unique features pertinent to COVID-19, many of its acute manifestations are similar to sepsis caused by other pathogens. As a consequence, the old definitions now require consideration of this new etiologic agent, namely SARS-CoV-2. Although the pathogenesis of COVID-19 has not been fully explained, the data obtained so far in hospitalized patients has revealed that serum cytokine and chemokine levels are high in severe COVID-19 patients, similar to those found with sepsis. COVID-19 may involve multiple organ systems. In addition to the lungs, the virus has been isolated from blood, urine, faeces, liver, and gallbladder. Results from autopsy series in COVID-19 patients have demonstrated a wide range of findings, including vascular involvement, congestion, consolidation, and hemorrhage as well as diffuse alveolar damage in lung tissue consistent with acute respiratory distress syndrome (ARDS). The presence of viral cytopathic-like changes, infiltration of inflammatory cells (mononuclear cells and macrophages), and viral particles in histopathological samples are considered a consequence of both direct viral infection and immune hyperactivation. Thromboembolism and hyper-coagulopathy are other components in the pathogenesis of severe COVID-19. Although the pathogenesis of hypercoagulability is not fully understood, it has been pointed out that all three components of Virchow’s triad (endothelial injury, stasis, and hypercoagulable state) play a major role in contributing to clot formation in severe COVID-19 infection. In severe COVID-19 cases, laboratory parameters such as hematological findings, coagulation tests, liver function tests, D-dimer, ferritin, and acute phase reactants such as CRP show marked alterations, which are suggestive of a cytokine storm. Another key element of COVID-19 pathogenesis in severe cases is its similarity or association with hemophagocytic lymphohistiocytosis (HLH). SARS-CoV-2 induced cytokine storm has significant clinical and laboratory findings overlapping with HLH. Viral sepsis has some similarities but also some differences when compared to bacterial sepsis. In bacterial sepsis, systemic inflammation affecting multiple organs is more dominant than in COVID-19 sepsis. While bacterial sepsis causes an early and sudden onset clinical deterioration, viral diseases may exhibit a relatively late onset and chronic course. Consideration of severe COVID-19 disease as a sepsis syndrome has relevance and may assist in terms of determining treatments that will modulate the immune response, limit intrinsic damage to tissue and organs, and potentially improve outcome.

Pathogenesis, Symptomatology, and Transmission of SARS-CoV-2 through Analysis of Viral Genomics and Structure

The novel coronavirus SARS-CoV-2, which emerged in late 2019, has since spread around the world and infected hundreds of millions of people with coronavirus disease 2019 (COVID-19). While this viral species was unknown prior to January 2020, its similarity to other coronaviruses that infect humans has allowed for rapid insight into the mechanisms that it uses to infect human hosts, as well as the ways in which the human immune system can respond. Here, we contextualize SARS-CoV-2 among other coronaviruses and identify what is known and what can be inferred about its behavior once inside a human host. Because the genomic content of coronaviruses, which specifies the virus's structure, is highly conserved, early genomic analysis provided a significant head start in predicting viral pathogenesis and in understanding potential differences among variants. The pathogenesis of the virus offers insights into symptomatology, transmission, and individual susceptibility. Additionally, prior research into interactions between the human immune system and coronaviruses has identified how these viruses can evade the immune system's protective mechanisms. We also explore systems-level research into the regulatory and proteomic effects of SARS-CoV-2 infection and the immune response. Understanding the structure and behavior of the virus serves to contextualize the many facets of the COVID-19 pandemic and can influence efforts to control the virus and treat the disease. IMPORTANCE COVID-19 involves a number of organ systems and can present with a wide range of symptoms. From how the virus infects cells to how it spreads between people, the available research suggests that these patterns are very similar to those seen in the closely related viruses SARS-CoV-1 and possibly Middle East respiratory syndrome-related CoV (MERS-CoV). Understanding the pathogenesis of the SARS-CoV-2 virus also contextualizes how the different biological systems affected by COVID-19 connect. Exploring the structure, phylogeny, and pathogenesis of the virus therefore helps to guide interpretation of the broader impacts of the virus on the human body and on human populations. For this reason, an in-depth exploration of viral mechanisms is critical to a robust understanding of SARS-CoV-2 and, potentially, future emergent human CoVs (HCoVs).

Nanotherapies for sepsis by regulating inflammatory signals and reactive oxygen and nitrogen species: New insight for treating COVID-19

SARS-CoV-2 has caused up to 127 million cases of COVID-19. Approximately 5% of COVID-19 patients develop severe illness, and approximately 40% of those with severe illness eventually die, corresponding to more than 2.78 million people. The pathological characteristics of COVID-19 resemble typical sepsis, and severe COVID-19 has been identified as viral sepsis. Progress in sepsis research is important for improving the clinical care of these patients. Recent advances in understanding the pathogenesis of sepsis have led to the view that an uncontrolled inflammatory response and oxidative stress are core factors. However, in the traditional treatment of sepsis, it is difficult to achieve a balance between the inflammation, pathogens (viruses, bacteria, and fungi), and patient tolerance, resulting in high mortality of patients with sepsis. In recent years, nanomaterials mediating reactive oxygen and nitrogen species (RONS) and the inflammatory response have shown previously unattainable therapeutic effects on sepsis. Despite these advantages, RONS and inflammatory response-based nanomaterials have yet to be extensively adopted as sepsis therapy. To the best of our knowledge, no review has yet discussed the pathogenesis of sepsis and the application of nanomaterials. To help bridge this gap, we discuss the pathogenesis of sepsis related to inflammation and the overproduction RONS, which activate pathogen-associated molecular pattern (PAMP)-pattern recognition receptor (PRR) and damage-associated molecular pattern (DAMP)-PRR signaling pathways. We also summarize the application of nanomaterials in the treatment of sepsis. As highlighted here, this strategy could synergistically improve the therapeutic efficacy against both RONS and inflammation in sepsis and may prolong survival. Current challenges and future developments for sepsis treatment are also summarized.

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

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

COVID-19-associated invasive pulmonary aspergillosis in a tertiary care center in Mexico City

Invasive pulmonary aspergillosis (IPA) is a severe infection caused by aspergillus sp. that usually develops in patients with severe immunosuppression. IPA has been recently described in critically ill COVID-19 patients (termed as COVID-associated pulmonary aspergillosis, or CAPA) that are otherwise immunocompetent. In order to describe the characteristics of patients with CAPA, we conducted a retrospective cohort study in a tertiary care center in Mexico City. We included all patients with confirmed COVID-19 admitted to the intensive care unit that had serum or bronchoalveolar lavage galactomannan measurements. We used the criteria proposed by Koehler et al. to establish the diagnosis of CAPA. Main outcomes were the need for invasive mechanical ventilation (IMV) and in-hospital mortality. Out of a total of 83 hospitalized patients with COVID-19 in the ICU, 16 (19.3%) met the criteria for CAPA. All patients diagnosed with CAPA required IMV whereas only 84% of the patients in the non-IPA group needed this intervention (P = 0.09). In the IPA group, 31% (n = 5) of the patients died, compared to 13% (n = 9) in the non-CAPA group (P = 0.08). We conclude that CAPA is a frequent co-infection in critically ill COVID-19 patients and is associated with a high mortality rate. The timely diagnosis and treatment of IPA in these patients is likely to improve their outcome.

LAY SUMMARY

We studied the characteristics of patients with COVID-19-associated invasive pulmonary aspergillosis (CAPA). Patients with CAPA tended to need invasive mechanical ventilation more frequently and to have a higher mortality rate. Adequate resources for its management can improve their outcome.

Characteristics of viral pneumonia in the COVID-19 era: an update

Influenza virus, rhinovirus, and adenovirus frequently cause viral pneumonia, an important cause of morbidity and mortality especially in the extreme ages of life. During the last two decades, three outbreaks of coronavirus-associated pneumonia, namely Severe Acute Respiratory Syndrome, Middle-East Respiratory Syndrome, and the ongoing Coronavirus Infectious Disease—2019 (COVID-19) were reported. The rate of diagnosis of viral pneumonia is increasingly approaching 60% among children identified as having community-acquired pneumonia (CAP). Clinical presentation ranges from mild to severe pneumonitis complicated by respiratory failure in severe cases. The most vulnerable patients, the elderly and those living with cancer, report a relevant mortality rate. No clinical characteristics can be useful to conclusively distinguish the different etiology of viral pneumonia. However, accessory symptoms, such as anosmia or ageusia together with respiratory symptoms suggest COVID-19. An etiologic-based treatment of viral pneumonia is possible in a small percentage of cases only. Neuraminidase inhibitors have been proven to reduce the need for ventilatory support and mortality rate while only a few data support the large-scale use of other antivirals. A low-middle dose of dexamethasone and heparin seems to be effective in COVID-19 patients, but data regarding their possible efficacy in viral pneumonia caused by other viruses are conflicting. In conclusion, viral pneumonia is a relevant cause of CAP, whose interest is increasing due to the current COVID-19 outbreak. To set up a therapeutic approach is difficult because of the low number of active molecules and the conflicting data bearing supportive treatments such as steroids.

The Good Treatment, the Bad Virus, and the Ugly Inflammation: Pathophysiology of Kidney Involvement During COVID-19

Kidney involvement is a common complication during SARS-CoV-2 infection. Its association with poor outcomes, especially in critically ill patients, raises issues whether kidney involvement reflects multi-organ damage or if it is a specific feature of the infection. Based on observational studies, autopsy series, and on current understanding of the route of entry of the virus, this review will highlight the different types of kidney involvement during COVID-19 and put them in the perspective of the different pathophysiological hypotheses. Virus entry route through ACE2 ligation and TMPRSS2 coligation allows identifying potential viral targets in the kidney, including tubules, endothelial cells, and glomerulus. While reports have described damages of all these structures and virus kidney tropism has been identified in renal extracts in autopsy series, no direct viral infection has been found in the latter structures thus far on kidney biopsies. Notwithstanding the technical challenge of disclosing viral invasion within tissues and cells, viral direct cytopathogenic effect generally does not appear as the cause of the observed renal damage. Inflammation and altered hemodynamics, described as "viral sepsis," might rather be responsible for organ dysfunction, including kidneys. We shall place these various mechanisms into an integrated vision where the synergy between direct viral pathogenicity and systemic inflammation enhances renal damage. As SARS-CoV-2 inexorably continues its rampant spread, understanding the sequence of events in the kidneys might thus help inform improved therapeutic strategies, including antiviral drugs and immunomodulators.