Characterization of the Inflammatory Response to Severe COVID-19 Illness

Persistent Lung Injury and Prothrombotic State in Long COVID

Lung injury may persist during the recovery period of COVID-19 as shown through imaging, six-minute walk, and lung function tests. The pathophysiological mechanisms leading to long COVID have not been adequately explained. Our aim is to investigate the basis of pulmonary susceptibility during sequelae and the possibility that prothrombotic states may influence long-term pulmonary symptoms of COVID-19. The patient’s lungs remain vulnerable during the recovery stage due to persistent shedding of the virus, the inflammatory environment, the prothrombotic state, and injury and subsequent repair of the blood-air barrier. The transformation of inflammation to proliferation and fibrosis, hypoxia-involved vascular remodeling, vascular endothelial cell damage, phosphatidylserine-involved hypercoagulability, and continuous changes in serological markers all contribute to post-discharge lung injury. Considering the important role of microthrombus and arteriovenous thrombus in the process of pulmonary functional lesions to organic lesions, we further study the possibility that prothrombotic states, including pulmonary vascular endothelial cell activation and hypercoagulability, may affect long-term pulmonary symptoms in long COVID. Early use of combined anticoagulant and antiplatelet therapy is a promising approach to reduce the incidence of pulmonary sequelae. Essentially, early treatment can block the occurrence of thrombotic events. Because impeded pulmonary circulation causes large pressure imbalances over the alveolar membrane leading to the infiltration of plasma into the alveolar cavity, inhibition of thrombotic events can prevent pulmonary hypertension, formation of lung hyaline membranes, and lung consolidation.

The Role of Cytokines and Chemokines in Severe Acute Respiratory Syndrome Coronavirus 2 Infections

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in countless infections and caused millions of deaths since its emergence in 2019. Coronavirus disease 2019 (COVID-19)-associated mortality is caused by uncontrolled inflammation, aberrant immune response, cytokine storm, and an imbalanced hyperactive immune system. The cytokine storm further results in multiple organ failure and lung immunopathology. Therefore, any potential treatments should focus on the direct elimination of viral particles, prevention strategies, and mitigation of the imbalanced (hyperactive) immune system. This review focuses on cytokine secretions of innate and adaptive immune responses against COVID-19, including interleukins, interferons, tumor necrosis factor-alpha, and other chemokines. In addition to the review focus, we discuss potential immunotherapeutic approaches based on relevant pathophysiological features, the systemic immune response against SARS-CoV-2, and data from recent clinical trials and experiments on the COVID-19-associated cytokine storm. Prompt use of these cytokines as diagnostic markers and aggressive prevention and management of the cytokine storm can help determine COVID-19-associated morbidity and mortality. The prophylaxis and rapid management of the cytokine storm appear to significantly improve disease outcomes. For these reasons, this study aims to provide advanced information to facilitate innovative strategies to survive in the COVID-19 pandemic.

Heart Failure Relapses in Response to Acute Stresses - Role of Immunological and Inflammatory Pathways

Cardiovascular diseases continue to be the most imminent health care problems in the western world, accounting for numerous deaths per year. Heart failure (HF), namely the reduction of left ventricular function, is one of the major cardiovascular disease entities. It is chronically progressing with relapsing acute decompensations and an overall grave prognosis that is little different if not worse than most malignant diseases. Interestingly acute metabolically and/or immunologically challenging events like infections or major surgical procedures will cause relapses in the course of preexisting chronic heart failure, decrease the patients wellbeing and worsen myocardial function. HF itself and or its progression has been demonstrated to be driven at least in part by inflammatory pathways that are similarly turned on by infectious or non-infectious stress responses. These thus add to HF progression or relapse. TNF-α plasma levels are associated with disease severity and progression in HF. In addition, several cytokines (e.g., IL-1β, IL-6) are involved in deteriorating left ventricular function. Those observations are based on clinical studies using inhibitors of cytokines or their receptors or they stem from animal studies examining the effect of cytokine mediated inflammation on myocardial remodeling in models of heart failure. This short review summarizes the known underlying immunological processes that are shared by and drive all: chronic heart failure, select infectious diseases, and inflammatory stress responses. In conclusion the text provides a brief summary of the current development in immunomodulatory therapies for HF and their overlap with treatments of other disease entities.

The Incidence of Myocarditis and Pericarditis in Post COVID-19 Unvaccinated Patients-A Large Population-Based Study

Myocarditis and pericarditis are potential post-acute cardiac sequelae of COVID-19 infection, arising from adaptive immune responses. We aimed to study the incidence of post-acute COVID-19 myocarditis and pericarditis. Retrospective cohort study of 196,992 adults after COVID-19 infection in Clalit Health Services members in Israel between March 2020 and January 2021. Inpatient myocarditis and pericarditis diagnoses were retrieved from day 10 after positive PCR. Follow-up was censored on 28 February 2021, with minimum observation of 18 days. The control cohort of 590,976 adults with at least one negative PCR and no positive PCR were age- and sex-matched. Since the Israeli vaccination program was initiated on 20 December 2020, the time-period matching of the control cohort was calculated backward from 15 December 2020. Nine post-COVID-19 patients developed myocarditis (0.0046%), and eleven patients were diagnosed with pericarditis (0.0056%). In the control cohort, 27 patients had myocarditis (0.0046%) and 52 had pericarditis (0.0088%). Age (adjusted hazard ratio [aHR] 0.96, 95% confidence interval [CI]; 0.93 to 1.00) and male sex (aHR 4.42; 95% CI, 1.64 to 11.96) were associated with myocarditis. Male sex (aHR 1.93; 95% CI 1.09 to 3.41) and peripheral vascular disease (aHR 4.20; 95% CI 1.50 to 11.72) were associated with pericarditis. Post COVID-19 infection was not associated with either myocarditis (aHR 1.08; 95% CI 0.45 to 2.56) or pericarditis (aHR 0.53; 95% CI 0.25 to 1.13). We did not observe an increased incidence of neither pericarditis nor myocarditis in adult patients recovering from COVID-19 infection.

Hypoxia Increases the Potential for Neutrophil-mediated Endothelial Damage in Chronic Obstructive Pulmonary Disease

Rationale: Patients with chronic obstructive pulmonary disease (COPD) experience excess cardiovascular morbidity and mortality, and exacerbations further increase the risk of such events. COPD is associated with persistent blood and airway neutrophilia and systemic and tissue hypoxia. Hypoxia augments neutrophil elastase release, enhancing capacity for tissue injury. Objective: To determine whether hypoxia-driven neutrophil protein secretion contributes to endothelial damage in COPD. Methods: The healthy human neutrophil secretome generated under normoxic or hypoxic conditions was characterized by quantitative mass spectrometry, and the capacity for neutrophil-mediated endothelial damage was assessed. Histotoxic protein concentrations were measured in normoxic versus hypoxic neutrophil supernatants and plasma from patients experiencing COPD exacerbation and healthy control subjects. Measurements and Main Results: Hypoxia promoted PI3Kγ-dependent neutrophil elastase secretion, with greater release seen in neutrophils from patients with COPD. Supernatants from neutrophils incubated under hypoxia caused pulmonary endothelial cell damage, and identical supernatants from COPD neutrophils increased neutrophil adherence to endothelial cells. Proteomics revealed differential neutrophil protein secretion under hypoxia and normoxia, and hypoxia augmented secretion of a subset of histotoxic granule and cytosolic proteins, with significantly greater release seen in COPD neutrophils. The plasma of patients with COPD had higher content of hypoxia-upregulated neutrophil-derived proteins and protease activity, and vascular injury markers. Conclusions: Hypoxia drives a destructive "hypersecretory" neutrophil phenotype conferring enhanced capacity for endothelial injury, with a corresponding signature of neutrophil degranulation and vascular injury identified in plasma of patients with COPD. Thus, hypoxic enhancement of neutrophil degranulation may contribute to increased cardiovascular risk in COPD. These insights may identify new therapeutic opportunities for endothelial damage in COPD.

Surviving the Storm: Cytokine Biosignature in SARS-CoV-2 Severity Prediction

Simple Summary

The world has been stricken mentally, physically, and economically by the COVID-19 virus. However, while SARS-CoV-2 viral infection results in mild flu-like symptoms in most patients, a number of those infected develop severe illness. These patients require hospitalization and intensive care. The severe disease can spiral downwards with eventual severe damage to the lungs and failure of multiple organs, leading to the individual’s demise. It is necessary to identify those who are developing a severe form of illness to provide early management. Therefore, it is crucial to learn about the mechanisms and chemical mediators that lead to critical conditions in SARS-CoV-2 infection. This paper reviews studies regarding the individual chemical mediators, pathways, and means that contribute to worsening health conditions in SARS-CoV-2 infection.

Abstract

A significant part of the world population has been affected by the devastating SARS-CoV-2 infection. It has deleterious effects on mental and physical health and global economic conditions. Evidence suggests that the pathogenesis of SARS-CoV-2 infection may result in immunopathology such as neutrophilia, lymphopenia, decreased response of type I interferon, monocyte, and macrophage dysregulation. Even though most individuals infected with the SARS-CoV-2 virus suffer mild symptoms similar to flu, severe illness develops in some cases, including dysfunction of multiple organs. Excessive production of different inflammatory cytokines leads to a cytokine storm in COVID-19 infection. The large quantities of inflammatory cytokines trigger several inflammation pathways through tissue cell and immune cell receptors. Such mechanisms eventually lead to complications such as acute respiratory distress syndrome, intravascular coagulation, capillary leak syndrome, failure of multiple organs, and, in severe cases, death. Thus, to devise an effective management plan for SARS-CoV-2 infection, it is necessary to comprehend the start and pathways of signaling for the SARS-CoV-2 infection-induced cytokine storm. This article discusses the current findings of SARS-CoV-2 related to immunopathology, the different paths of signaling and other cytokines that result in a cytokine storm, and biomarkers that can act as early signs of warning for severe illness. A detailed understanding of the cytokine storm may aid in the development of effective means for controlling the disease’s immunopathology. In addition, noting the biomarkers and pathophysiology of severe SARS-CoV-2 infection as early warning signs can help prevent severe complications.

Vitamin D: The Missing Nutrient Behind the Two Deadly Pandemics, COVID-19 and Cardiovascular Diseases

The coronavirus (COVID-19) pandemic is claiming millions of lives and creating an additional burden on health care, which is already affected by the rise of non-communicable diseases (NCDs). The scientific community, on the other side, is enormously engaged with studies to best identify the characteristics of the virus and minimize its effect while supporting the fight to contain NCDs, mainly cardiovascular diseases (CVDs), which are contributing hugely to the global death toll. Hence, the roles of vitamin D in COVID-19 immunity and cardiovascular health are gaining traction recently. 

This literature review will mainly focus on summarizing pertinent studies and scientific publications which highlight the association of vitamin D levels with the various outcomes of COVID-19 and CVDs. It will also address how low vitamin D correlates with the epidemiology of CVDs and the inflammatory mechanisms attributed to COVID-19 severity. We believe that our review may open up hindsight perspectives and further discussions among the physicians in tapping the potential of vitamin D supplementation to tackle the morbidity, mortality, and health care cost of the two deadly diseases, COVID-19 and CVDs. 

In Vitro SARS-CoV-2 Infection of Microvascular Endothelial Cells: Effect on Pro-Inflammatory Cytokine and Chemokine Release

In the novel pandemic of Coronavirus Disease 2019, high levels of pro-inflammatory cytokines lead to endothelial activation and dysfunction, promoting a pro-coagulative state, thrombotic events, and microvasculature injuries. The aim of the present work was to investigate the effect of SARS-CoV-2 on pro-inflammatory cytokines, tissue factor, and chemokine release, with Human Microvascular Endothelial Cells (HMEC-1). ACE2 receptor expression was evaluated by western blot analysis. SARS-CoV-2 infection was assessed by one-step RT-PCR until 7 days post-infection (p.i.), and by Transmission Electron Microscopy (TEM). IL-6, TNF-α, IL-8, IFN-α, and hTF mRNA expression levels were detected by RT-PCR, while cytokine release was evaluated by ELISA. HMEC-1 expressed ACE2 receptor and SARS-CoV-2 infection showed a constant viral load. TEM analysis showed virions localized in the cytoplasm. Expression of IL-6 at 24 h and IFN-α mRNA at 24 h and 48 h p.i. was higher in infected than uninfected HMEC-1 (p < 0.05). IL-6 levels were significantly higher in supernatants from infected HMEC-1 (p < 0.001) at 24 h, 48 h, and 72 h p.i., while IL-8 levels were significantly lower at 24 h p.i. (p < 0.001). These data indicate that in vitro microvascular endothelial cells are susceptible to SARS-CoV-2 infection but slightly contribute to viral amplification. However, SARS-CoV-2 infection might trigger the increase of pro-inflammatory mediators.

Pro-inflammatory immune profile mediated by TNF and IFN-γ and regulated by IL-10 is associated to IgG anti-SARS-CoV-2 in asymptomatic blood donors

The SARS-CoV-2 virus has infected and killed millions of people, but little is known about the risk factors that lead to the development of severe, mild or asymptomatic conditions after infection. The individual immune response and the balance of cytokines and chemokines have been shown to be important for the prognosis of patients. Additionally, it is essential to understand how the production of specific antibodies with viral neutralizing capacity is established. In this context, this study aimed to identify positive individuals for IgG anti-SARS-CoV-2 in a large population of blood donors (n = 7837) to establish their immune response profile and to evaluate its viral neutralization capacity. The prevalence found for IgG anti-SARS-CoV-2 was 5.6% (n = 441), with male blood donors (61.9%) being more prevalent among the positive ones. The results showed that positive individuals for IgG anti-SARS-CoV-2 have high serum concentrations of chemokines, TNF, IFN-γ and IL-10. The analyses showed that the positivity index for IgG anti-SARS-CoV-2 is associated with the neutralizing capacity of the antibodies, which, in turn, is significantly related to lower serum concentrations of CCL5 and CXCL10. The results allow us to hypothesize that the development and maintenance of IgG anti-SARS-CoV-2 antibodies in infected individuals occurs in a pro-inflammatory microenvironment well regulated by IL-10 with great capacity for recruiting cells from the innate and adaptive immune systems.

Immunopathological changes, complications, sequelae and immunological memory in COVID-19 patients

Confirmed SARS-CoV-2-caused disease (COVID-19) cases have reached 275.65 million worldwide. Although the majority of COVID-19 patients present mild to moderate symptoms, some have severe complications including death. We first reviewed the pathogenesis on ACE2, a binding receptor of SARS-CoV-2 expressed in multiple organs, and prevalent multinucleate syncytia in the lung tissues of COVID-19 patients. Then, we evaluated the pathological, immunological changes and sequelae in the major organs. Finally, we reviewed the immunological memory after SARS-CoV-2 infection and vaccination. The binding of SARS-Cov-2 to ACE2 receptor results in reduced ACE2 protein levels, which may lead to elevated susceptibility to inflammation, cell death, organ failure, and potentially severe illness. These damages increase the risk of health problems over a long period, which result in many complications. The complications in multiple organs lead to the increased risk of long-term health problems that require additional attention. A multidisciplinary care team is necessary for further management and recovery of the COVID-19 survivors. Many COVID-19 patients will probably make antibodies against SARS-CoV-2 virus for most of their lives, and the immunity against reinfection would last for 3-61 months.

[Persistent COVID-19 syndrome. A narrative review]

As the coronavirus-2019 disease (COVID-19) pandemic, caused by the infection with severe acute respiratory syndrome (SARS-CoV-2) coronavirus type 2, has progressed, persistent COVID-19 syndrome is an increasingly recognized problem on which a significant volume of medical literature is developing. Symptoms may be persistent or appear, after an asymptomatic period, weeks or months after the initial infection. The clinical picture is as markedly heterogeneous and multisystemic as in the acute phase, so multidisciplinary management is required. In addition, their appearance is not related to the severity of the initial infection, so they can affect both mild patients, even asymptomatic, and seriously ill patients who have required hospitalization. Although it can affect people of any age, it is more common in middle-aged women. The sequelae can generate a high impact on the quality of life, and in the work and social environment. The objective of this paper is to review persistent COVID-19 syndrome, to know its clinical manifestations and the strategies for the management and follow-up of these patients.

Persistent COVID-19 syndrome. A narrative review

As the coronavirus-2019 disease (COVID-19) pandemic, caused by the infection with severe acute respiratory syndrome (SARS-CoV-2) coronavirus type 2, has progressed, persistent COVID-19 syndrome is an increasingly recognized problem on which a significant volume of medical literature is developing. Symptoms may be persistent or appear, after an asymptomatic period, weeks or months after the initial infection. The clinical picture is as markedly heterogeneous and multisystemic as in the acute phase, so multidisciplinary management is required. In addition, their appearance is not related to the severity of the initial infection, so they can affect both mild patients, even asymptomatic, and seriously ill patients who have required hospitalization. Although it can affect people of any age, it is more common in middle-aged women. The sequelae can generate a high impact on the quality of life, and in the work and social environment. The objective of this paper is to review persistent COVID-19 syndrome, to know its clinical manifestations and the strategies for the management and follow-up of these patients.

Beneficial ex vivo immunomodulatory and clinical effects of clarithromycin in COVID-19

Introduction

Macrolide antibiotics have immunomodulatory properties which may be beneficial in viral infections. However, the precise effects of macrolides on T cell responses to COVID, differences between different macrolides, and synergistic effects with other antibiotics have not been explored.

Methods

We investigated the effect of antibiotics (amoxicillin, azithromycin, clarithromycin, and combined amoxicillin with clarithromycin) on lymphocyte intracellular cytokine levels and monocyte phagocytosis in healthy volunteer PBMCs stimulated ex vivo with SARS-CoV-2 S1+2 spike protein. A retrospective cohort study was performed on intensive care COVID-19 patients.

Results

Co-incubation of clarithromycin with spike protein-stimulated healthy volunteer PBMCs ex vivo resulted in an increase in CD8⁺ (p = 0.004) and CD4⁺ (p = 0.007) IL-2, with a decrease in CD8⁺ (p = 0.032) and CD4⁺ (p = 0.007) IL-10. The addition of amoxicillin to clarithromycin resulted in an increase in CD8⁺ IL-6 (p = 0.010), decrease in CD8⁺ (p = 0.014) and CD4⁺ (p = 0.022) TNF-alpha, and decrease in CD8⁺ IFN-alpha (p = 0.038). Amoxicillin alone had no effect on CD4⁺ or CD8⁺ cytokines. Co-incubation of azithromycin resulted in increased CD8⁺ (p = 0.007) and CD4⁺ (p = 0.011) IL-2. There were no effects on monocyte phagocytosis. 102 COVID-19 ICU patients received antibiotics on hospital admission; 62 (61%) received clarithromycin. Clarithromycin use was associated with reduction in mortality on univariate analysis (p = 0.023), but not following adjustment for confounders (HR = 0.540; p = 0.076).

Conclusions

Clarithromycin has immunomodulatory properties over and above azithromycin. Amoxicillin in addition to clarithromycin is associated with synergistic ex vivo immunomodulatory properties. The potential benefit of clarithromycin in critically ill patients with COVID-19 and other viral pneumonitis merits further exploration.

Progress on SARS-CoV-2 3CLpro Inhibitors: Inspiration from SARS-CoV 3CLpro Peptidomimetics and Small-Molecule Anti-Inflammatory Compounds

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) currently poses a threat to human health. 3C-like proteinase (3CLpro) plays an important role in the viral life cycle. Hence, it is considered an attractive antiviral target protein. Whole-genome sequencing showed that the sequence homology between SARS-CoV-2 3CLpro and SARS-CoV 3CLpro is 96.08%, with high similarity in the substrate-binding region. Thus, assessing peptidomimetic inhibitors of SARS-CoV 3CLpro could accelerate the development of peptidomimetic inhibitors for SARS-CoV-2 3CLpro. Accordingly, we herein discuss progress on SARS-CoV-2 3CLpro peptidomimetic inhibitors. Inflammation plays a major role in the pathophysiological process of COVID-19. Small-molecule compounds targeting 3CLpro with both antiviral and anti-inflammatory effects are also briefly discussed in this paper.

Metabolic Reprogramming in HIV-Associated Neurocognitive Disorders

A significant number of patients infected with HIV-1 suffer from HIV-associated neurocognitive disorders (HAND) such as spatial memory impairments and learning disabilities (SMI-LD). SMI-LD is also observed in patients using combination antiretroviral therapy (cART). Our lab has demonstrated that the HIV-1 protein, gp120, promotes SMI-LD by altering mitochondrial functions and energy production. We have investigated cellular processes upstream of the mitochondrial functions and discovered that gp120 causes metabolic reprogramming. Effectively, the addition of gp120 protein to neuronal cells disrupted the glycolysis pathway at the pyruvate level. Looking for the players involved, we found that gp120 promotes increased expression of polypyrimidine tract binding protein 1 (PTBP1), causing the splicing of pyruvate kinase M (PKM) into PKM1 and PKM2. We have also shown that these events lead to the accumulation of advanced glycation end products (AGEs) and prevent the cleavage of pro-brain-derived neurotrophic factor (pro-BDNF) protein into mature brain-derived neurotrophic factor (BDNF). The accumulation of proBDNF results in signaling that increases the expression of the inducible cAMP early repressor (ICER) protein which then occupies the cAMP response element (CRE)-binding sites within the BDNF promoters II and IV, thus altering normal synaptic plasticity. We reversed these events by adding Tepp-46, which stabilizes the tetrameric form of PKM2. Therefore, we concluded that gp120 reprograms cellular metabolism, causing changes linked to disrupted memory in HIV-infected patients and that preventing the disruption of the metabolism presents a potential cure against HAND progression.

Enoxaparin augments alpha-1-antitrypsin inhibition of TMPRSS2, a promising drug combination against COVID-19

The cell surface serine protease Transmembrane Protease 2 (TMPRSS2) is required to cleave the spike protein of SARS-CoV-2 for viral entry into cells. We determined whether negatively-charged heparin enhanced TMPRSS2 inhibition by alpha-1-antitrypsin (AAT). TMPRSS2 activity was determined in HEK293T cells overexpressing TMPRSS2. We quantified infection of primary human airway epithelial cells (hAEc) with human coronavirus 229E (HCoV-229E) by immunostaining for the nucleocapsid protein and by the plaque assay. Detailed molecular modeling was undertaken with the heparin-TMPRSS2-AAT ternary complex. Enoxaparin enhanced AAT inhibition of both TMPRSS2 activity and infection of hAEc with HCoV-229E. Underlying these findings, detailed molecular modeling revealed that: (i) the reactive center loop of AAT adopts an inhibitory-competent conformation compared with the crystal structure of TMPRSS2 bound to an exogenous (nafamostat) or endogenous (HAI-2) TMPRSS2 inhibitor and (ii) negatively-charged heparin bridges adjacent electropositive patches at the TMPRSS2-AAT interface, neutralizing otherwise repulsive forces. In conclusion, enoxaparin enhances AAT inhibition of both TMPRSS2 and coronavirus infection. Such host-directed therapy is less likely to be affected by SARS-CoV-2 mutations. Furthermore, given the known anti-inflammatory activities of both AAT and heparin, this form of treatment may target both the virus and the excessive inflammatory consequences of severe COVID-19.

Ibrutinib for Hospitalized Adults with Severe COVID-19 Infection: Results of the Randomized, Double-Blind, Placebo-Controlled iNSPIRE Study

Background

Few therapies are approved for hospitalized patients with severe coronavirus disease 2019 (COVID-19). Ibrutinib, a once-daily Bruton tyrosine kinase inhibitor, may mitigate COVID-19–induced lung damage by reducing inflammatory cytokines. The multicenter, randomized, double-blind phase 2 iNSPIRE study evaluated ibrutinib for prevention of respiratory failure in hospitalized patients with severe COVID-19.

Methods

Adult patients with severe COVID-19 requiring hospitalization and supplemental oxygen but without respiratory failure were randomized 1:1 (stratified by remdesivir prescription) to ibrutinib 420 mg or placebo once daily for up to 28 days plus standard of care (SOC), including remdesivir and/or dexamethasone.

Results

Forty-six patients were randomized to ibrutinib plus SOC (n = 22) or placebo plus SOC (n = 24). The primary endpoint (proportion of patients alive and without respiratory failure through day 28) was not met, with no statistically significant difference adjusting for remdesivir prescription (86% with ibrutinib plus SOC vs 79% with placebo plus SOC; adjusted difference, 5.8% [80% confidence interval, –9.2% to 20.4%]; P = .599). Secondary endpoints also showed no statistically significant improvement with ibrutinib plus SOC. Median treatment duration was 14 days for ibrutinib and placebo. Adverse events were similar with ibrutinib plus SOC vs placebo plus SOC (overall: 55% vs 50%; serious: 18% vs 13%) and were consistent with the known safety profile of ibrutinib.

Conclusions

Addition of ibrutinib to SOC did not improve the proportion of patients alive and without respiratory failure through day 28 in hospitalized patients with severe COVID-19. Ibrutinib had a manageable safety profile, with similar safety to placebo.

Clinical Trials Registration

NCT04375397.

Development of off-the-shelf hematopoietic stem cell-engineered invariant natural killer T cells for COVID-19 therapeutic intervention

BACKGROUND

New COVID-19 treatments are desperately needed as case numbers continue to rise and emergent strains threaten vaccine efficacy. Cell therapy has revolutionized cancer treatment and holds much promise in combatting infectious disease, including COVID-19. Invariant natural killer T (iNKT) cells are a rare subset of T cells with potent antiviral and immunoregulatory functions and an excellent safety profile. Current iNKT cell strategies are hindered by the extremely low presence of iNKT cells, and we have developed a platform to overcome this critical limitation.

METHODS

We produced allogeneic HSC-engineered iNKT (AlloHSC-iNKT) cells through TCR engineering of human cord blood CD34+ hematopoietic stem cells (HSCs) and differentiation of these HSCs into iNKT cells in an Ex Vivo HSC-Derived iNKT Cell Culture. We then established in vitro SARS-CoV-2 infection assays to assess AlloHSC-iNKT cell antiviral and anti-hyperinflammation functions. Lastly, using in vitro and in vivo preclinical models, we evaluated AlloHSC-iNKT cell safety and immunogenicity for off-the-shelf application.

RESULTS

We reliably generated AlloHSC-iNKT cells at high-yield and of high-purity; these resulting cells closely resembled endogenous human iNKT cells in phenotypes and functionalities. In cell culture, AlloHSC-iNKT cells directly killed SARS-CoV-2 infected cells and also selectively eliminated SARS-CoV-2 infection-stimulated inflammatory monocytes. In an in vitro mixed lymphocyte reaction (MLR) assay and an NSG mouse xenograft model, AlloHSC-iNKT cells were resistant to T cell-mediated alloreaction and did not cause GvHD.

CONCLUSIONS

Here, we report a method to robustly produce therapeutic levels of AlloHSC-iNKT cells. Preclinical studies showed that these AlloHSC-iNKT cells closely resembled endogenous human iNKT cells, could reduce SARS-CoV-2 virus infection load and mitigate virus infection-induced hyperinflammation, and meanwhile were free of GvHD-risk and resistant to T cell-mediated allorejection. These results support the development of AlloHSC-iNKT cells as a promising off-the-shelf cell product for treating COVID-19; such a cell product has the potential to target the new emerging SARS-CoV-2 variants as well as the future new emerging viruses.

A case of successive development of possible acute necrotizing encephalopathy after COVID-19 pneumonia

COVID-19 infection often results in an excessive inflammatory response with a spectrum of neurological manifestations. Here, we describe an 81-year-old female with severe COVID-19 pneumonia and subsequent alteration of consciousness after high-dose intravenous dexamethasone and remdesivir. A non-contrast head computed tomography (CT) demonstrated bilateral hypodensities involving bilateral cerebellar hemispheres, thalami, cerebral peduncles and medial parieto-occipital areas. There was no improvement and repeat CT showed progression with findings suggestive of acute necrotizing encephalopathy. Interleukin-6 levels were initially normal; however, subsequent levels were found to be markedly elevated. Acute necrotizing encephalopathy associated with COVID-19 may occur in the setting of severe pneumonia and may represent an immune-mediated process involving inflammatory cytokines such as interleukin-6.

A hybrid machine learning/deep learning COVID-19 severity predictive model from CT images and clinical data

COVID-19 clinical presentation and prognosis are highly variable, ranging from asymptomatic and paucisymptomatic cases to acute respiratory distress syndrome and multi-organ involvement. We developed a hybrid machine learning/deep learning model to classify patients in two outcome categories, non-ICU and ICU (intensive care admission or death), using 558 patients admitted in a northern Italy hospital in February/May of 2020. A fully 3D patient-level CNN classifier on baseline CT images is used as feature extractor. Features extracted, alongside with laboratory and clinical data, are fed for selection in a Boruta algorithm with SHAP game theoretical values. A classifier is built on the reduced feature space using CatBoost gradient boosting algorithm and reaching a probabilistic AUC of 0.949 on holdout test set. The model aims to provide clinical decision support to medical doctors, with the probability score of belonging to an outcome class and with case-based SHAP interpretation of features importance.

Physiological and Pathophysiological Roles of Metabolic Pathways for NET Formation and Other Neutrophil Functions

Neutrophils are the most numerous cells in the leukocyte population and essential for innate immunity. To limit their effector functions, neutrophils are able to modulate glycolysis and other cellular metabolic pathways. These metabolic pathways are essential not only for energy usage, but also for specialized effector actions, such as the production of reactive oxygen species (ROS), chemotaxis, phagocytosis, degranulation, and the formation of neutrophil extracellular traps (NETs). It has been demonstrated that activated viable neutrophils can produce NETs, which consists of a DNA scaffold able to bind granule proteins and microorganisms. The formation of NETs requires the availability of increased amounts of adenosine triphosphate (ATP) as it is an active cellular and therefore energy-dependent process. In this article, we discuss the glycolytic and other metabolic routes in association with neutrophil functions focusing on their role for building up NETs in the extracellular space. A better understanding of the requirements of metabolic pathways for neutrophil functions may lead to the discovery of molecular targets suitable to develop novel anti-infectious and/or anti-inflammatory drugs.

Cognitive, EEG, and MRI features of COVID-19 survivors: a 10-month study

Background and objectives

To explore cognitive, EEG, and MRI features in COVID-19 survivors up to 10 months after hospital discharge.

Methods

Adult patients with a recent diagnosis of COVID-19 and reporting subsequent cognitive complaints underwent neuropsychological assessment and 19-channel-EEG within 2 months (baseline, N = 49) and 10 months (follow-up, N = 33) after hospital discharge. A brain MRI was obtained for 36 patients at baseline. Matched healthy controls were included. Using eLORETA, EEG regional current densities and linear lagged connectivity values were estimated. Total brain and white matter hyperintensities (WMH) volumes were measured. Clinical and instrumental data were evaluated between patients and controls at baseline, and within patient whole group and with/without dysgeusia/hyposmia subgroups over time. Correlations among findings at each timepoint were computed.

Results

At baseline, 53% and 28% of patients showed cognitive and psychopathological disturbances, respectively, with executive dysfunctions correlating with acute-phase respiratory distress. Compared to healthy controls, patients also showed higher regional current density and connectivity at delta band, correlating with executive performances, and greater WMH load, correlating with verbal memory deficits. A reduction of cognitive impairment and delta band EEG connectivity were observed over time, while psychopathological symptoms persisted. Patients with acute dysgeusia/hyposmia showed lower improvement at memory tests than those without. Lower EEG delta band at baseline predicted worse cognitive functioning at follow-up.

Discussion

COVID-19 patients showed interrelated cognitive, EEG, and MRI abnormalities 2 months after hospital discharge. Cognitive and EEG findings improved at 10 months. Dysgeusia and hyposmia during acute COVID-19 were related with increased vulnerability in memory functions over time.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11047-5.

Nucleic Acid-Based COVID-19 Therapy Targeting Cytokine Storms: Strategies to Quell the Storm

Coronavirus disease 2019 (COVID-19) has shaken the world and triggered drastic changes in our lifestyle to control it. Despite the non-typical efforts, COVID-19 still thrives and plagues humanity worldwide. The unparalleled degree of infection has been met with an exceptional degree of research to counteract it. Many drugs and therapeutic technologies have been repurposed and discovered, but no groundbreaking antiviral agent has been introduced yet to eradicate COVID-19 and restore normalcy. As lethality is directly correlated with the severity of disease, hospitalized severe cases are of the greatest importance to reduce, especially the cytokine storm phenomenon. This severe inflammatory phenomenon characterized by elevated levels of inflammatory mediators can be targeted to relieve symptoms and save the infected patients. One of the promising therapeutic strategies to combat COVID-19 is nucleic acid-based therapeutic approaches, including microRNAs (miRNAs). This work is an up-to-date review aimed to comprehensively discuss the current nucleic acid-based therapeutics against COVID-19 and their mechanisms of action, taking into consideration the emerging SARS-CoV-2 variants of concern, as well as providing potential future directions. miRNAs can be used to run interference with the expression of viral proteins, while endogenous miRNAs can be targeted as well, offering a versatile platform to control SARS-CoV-2 infection. By targeting these miRNAs, the COVID-19-induced cytokine storm can be suppressed. Therefore, nucleic acid-based therapeutics (miRNAs included) have a latent ability to break the COVID-19 infection in general and quell the cytokine storm in particular.

Molecular and Clinical Prognostic Biomarkers of COVID-19 Severity and Persistence

The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), poses several challenges to clinicians, due to its unpredictable clinical course. The identification of laboratory biomarkers, specific cellular, and molecular mediators of immune response could contribute to the prognosis and management of COVID-19 patients. Of utmost importance is also the detection of differentially expressed genes, which can serve as transcriptomic signatures, providing information valuable to stratify patients into groups, based on the severity of the disease. The role of biomarkers such as IL-6, procalcitonin, neutrophil-lymphocyte ratio, white blood cell counts, etc. has already been highlighted in recently published studies; however, there is a notable amount of new evidence that has not been summarized yet, especially regarding transcriptomic signatures. Hence, in this review, we assess the latest cellular and molecular data and determine the significance of abnormalities in potential biomarkers for COVID-19 severity and persistence. Furthermore, we applied Gene Ontology (GO) enrichment analysis using the genes reported as differentially expressed in the literature in order to investigate which biological pathways are significantly enriched. The analysis revealed a number of processes, such as inflammatory response, and monocyte and neutrophil chemotaxis, which occur as part of the complex immune response to SARS-CoV-2.

Immunomodulation of COVID‐19 severity by helminth co‐infection: Implications for COVID‐19 vaccine efficacy

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), an emerging virus in late 2019 causing coronavirus disease 2019 (COVID‐19), has caused a catastrophic effect, resulting in an unprecedented global crisis. The immunopathology of COVID‐19 appears to be clearly associated with a dysregulated immune response leading to organ failure and death. Similarly, over two billion people worldwide are infected with helminth, with those living in low‐middle‐income countries disproportionately affected. Helminth infections have been shown to possess immunomodulatory effects in several conditions. Helminth co‐infection in COVID‐19 patients is one of the potential reasons for global attention to answer why COVID‐19 severity is still lower in helminth endemic countries. Recent studies have shown that helminth endemic countries showed fewer cases and deaths so far and helminth co‐infection might reduce the severity of COVID‐19. Moreover, lessons from other diseases with helminth co‐infection have been shown to substantially reduce vaccine efficacy that could also be implicated for COVID‐19. This immunomodulatory effect of helminth has intended and unintended consequences, both advantageous and disadvantageous which could decrease the severity of COVID‐19 and COVID‐19 vaccine efficacy respectively. Herewith, we discuss the overview of COVID‐19 immune response, immunomodulatory effects of helminth co‐infections in COVID‐19, lessons from other diseases, and perspectives on the efficacy of COVID‐19 vaccines.

The Potential Predictive Role of Tumour Necrosis Factor-α, Interleukin-1β, and Monocyte Chemoattractant Protein-1 for COVID-19 Patients Survival

Background

Tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1) are early phase cytokines often encountered when the body is exposed to severe acute respiratory syndrome-associated-coronavirus-2. TNF-α, IL-1β, and MCP-1 are pro-inflammatory cytokines critical in the defence response against systemic infection and injury. Therefore, TNF-α, IL-1β, and MCP-1 are the most aggressive responses to viral infections in the acute phase, so they can be used to determine the survival of coronavirus disease 2019 (COVID-19) patients.

Purpose

The study aimed to determine the levels of TNF-α, IL-1β, and MCP-1 as predictors of survival for COVID-19 patients.

Patients and Methods

A prospective cohort study was conducted on confirmed COVID-19 by a reverse-transcriptase-polymerase-chain-reaction (RT-PCR) in 84 adults admitted to the hospital in Indonesia. TNF-α, IL-1β, and MCP-1 level were measured from serum subjects using the enzyme-linked immunosorbent assay.

Results

The results from logistic regression modelling of the survival status of COVID-19 patients based on TNF-α, IL-1β, and MCP-1 levels were significant (p-value=0.024). The predictors of all cytokines had P Wald <0.05, so the three cytokines could be used simultaneously to predict the survival status of COVID-19 patients. MCP-1 has the most dominant risk relative value (2.76; 95% CI; 2.53–4.68) compared to TNF-α and IL-1β in predicting patient survival.

Conclusion

TNF-α, IL-1β, and MCP-1 as markers of acute systemic inflammatory cytokines can be measured at the beginning of hospitalisation of COVID-19 patients for early diagnosis of disease severity so that healthcare professionals can determine clinical guidance needs for therapeutic programs.

High Serum Progranulin Levels in COVID-19 Patients: A Pilot Study

In this study, we aimed to determine whether the progranulin level in serum predicts the course and severity of the disease in COVID-19 (+) patients and whether it can be used as a biomarker in these patients. Therefore, we sampled 61 people infected with COVID-19, and the cases were divided into the following groups: asymptomatic, noncomplicated, moderate, and severe. Concentrations of progranulin, TNF-α, IL-6 from in serum obtained from all participants were measured using commercially available ELISA kits, as well as WBC, PLT, NE, LY, ALT, AST, Hb, PCT, and CRP were examined with clinical analyzer. All measurements obtained for the patient samples were compared with those of 20 healthy individuals. The serum progranulin concentration was statistically higher in the COVID-19 (+) patient group than in the control group of healthy individuals [112.6 ± 54.8, 0.0 (0.0-54.2 pg/ml, respectively p = 0.000)]. ROC analysis was performed to evaluate the progranulin potential as a biomarker for COVID-19 (+) patients. A larger AUC (0.931 ± 0.08) value and a more significant p-value for progranulin than for CRP (p = 0.000) was detected. As a result, we believe that progranulin reaches high levels in the COVID-19 disease and may be a determinant in diagnosis and prognosis, and may be a better biomarker than CRP.

A randomized, double-blind, placebo-controlled trial of intravenous alpha-1 antitrypsin for acute respiratory distress syndrome secondary to COVID-19

Background

Patients with severe coronavirus disease 2019 (COVID-19) develop a febrile pro-inflammatory cytokinemia with accelerated progression to acute respiratory distress syndrome (ARDS). Here we report the results of a phase 2, multicenter, randomized, double-blind, placebo-controlled trial of intravenous (IV) plasma-purified alpha-1 antitrypsin (AAT) for moderate to severe ARDS secondary to COVID-19 (EudraCT 2020-001391-15).

Methods

Patients (n = 36) were randomized to receive weekly placebo, weekly AAT (Prolastin, Grifols, S.A.; 120 mg/kg), or AAT once followed by weekly placebo. The primary endpoint was the change in plasma interleukin (IL)-6 concentration at 1 week. In addition to assessing safety and tolerability, changes in plasma levels of IL-1β, IL-8, IL-10, and soluble tumor necrosis factor receptor 1 (sTNFR1) and clinical outcomes were assessed as secondary endpoints.

Findings

Treatment with IV AAT resulted in decreased inflammation and was safe and well tolerated. The study met its primary endpoint, with decreased circulating IL-6 concentrations at 1 week in the treatment group. This was in contrast to the placebo group, where IL-6 was increased. Similarly, plasma sTNFR1 was substantially decreased in the treatment group while remaining unchanged in patients receiving placebo. IV AAT did not definitively reduce levels of IL-1β, IL-8, and IL-10. No difference in mortality or ventilator-free days was observed between groups, although a trend toward decreased time on ventilator was observed in AAT-treated patients.

Conclusions

In patients with COVID-19 and moderate to severe ARDS, treatment with IV AAT was safe, feasible, and biochemically efficacious. The data support progression to a phase 3 trial and prompt further investigation of AAT as an anti-inflammatory therapeutic.

Funding

ECSA-2020-009; Elaine Galwey Research Bursary.

Detection of COVID-19 severity using blood gas analysis parameters and Harris hawks optimized extreme learning machine

Coronavirus disease-2019 (COVID-19) has made the world more cautious about widespread viruses, and a tragic pandemic that was caused by a novel coronavirus has harmed human beings in recent years. The new coronavirus pneumonia outbreak is spreading rapidly worldwide. We collect arterial blood samples from 51 patients with a COVID-19 diagnosis. Blood gas analysis is performed using a Siemens RAPID Point 500 blood gas analyzer. To accurately determine the factors that play a decisive role in the early recognition and discrimination of COVID-19 severity, a prediction framework that is based on an improved binary Harris hawk optimization (HHO) algorithm in combination with a kernel extreme learning machine is proposed in this paper. This method uses specular reflection learning to improve the original HHO algorithm and is referred to as HHOSRL. The experimental results show that the selected indicators, such as age, partial pressure of oxygen, oxygen saturation, sodium ion concentration, and lactic acid, are essential for the early accurate assessment of COVID-19 severity by the proposed feature selection method. The simulation results show that the established methodlogy can achieve promising performance. We believe that our proposed model provides an effective strategy for accurate early assessment of COVID-19 and distinguishing disease severity. The codes of HHO will be updated in https://aliasgharheidari.com/HHO.html.

Protease-anti-protease compartmentalization in SARS-CoV-2 ARDS: Therapeutic implications

Background

Interleukin-6 (IL-6) is elevated in SARS-CoV-2 infection. IL-6 regulates acute-phase proteins, such as alpha-1 antitrypsin (AAT), a key lung anti-protease. We investigated the protease-anti-protease balance in the circulation and pulmonary compartments in SARS-CoV-2 acute respiratory distress syndrome (ARDS) compared to non-SARS-CoV-2 ARDS (nsARDS) and the effects of tocilizumab (IL-6 receptor antagonist) on anti-protease defence in SARS-CoV-2 infection.

Methods

Levels and activity of AAT and neutrophil elastase (NE) were measured in plasma, airway tissue and tracheal secretions (TA) of people with SARS-CoV-2 ARDS or nsARDS. AAT and IL-6 levels were evaluated in people with moderate SARS-CoV-2 infection who received standard of care +/- tocilizumab.

Findings

AAT plasma levels doubled in SARS-CoV-2 ARDS. In lung parenchyma AAT levels were increased, as was the percentage of neutrophils involved in NET formation. A protease-anti-protease imbalance was detected in TA with active NE and no active AAT. The airway anti-protease, secretory leukoprotease inhibitor was decreased in SARS-CoV-2-infected lungs and cleaved in TA. In nsARDS, plasma AAT levels were elevated but TA samples had less AAT cleavage, with no detectable active NE in most samples

Induction of AAT in ARDS occurred mainly through IL-6. Tocilizumab down-regulated AAT during SARS-CoV-2 infection.

Interpretation

There is a protease-anti-protease imbalance in the airways of SARS-CoV-2-ARDS patients. This imbalance is a target for anti-protease therapy.

A Review of Alpha-1 Antitrypsin Binding Partners for Immune Regulation and Potential Therapeutic Application

Alpha-1 antitrypsin (AAT) is the canonical serine protease inhibitor of neutrophil-derived proteases and can modulate innate immune mechanisms through its anti-inflammatory activities mediated by a broad spectrum of protein, cytokine, and cell surface interactions. AAT contains a reactive methionine residue that is critical for its protease-specific binding capacity, whereby AAT entraps the protease on cleavage of its reactive centre loop, neutralises its activity by key changes in its tertiary structure, and permits removal of the AAT-protease complex from the circulation. Recently, however, the immunomodulatory role of AAT has come increasingly to the fore with several prominent studies focused on lipid or protein-protein interactions that are predominantly mediated through electrostatic, glycan, or hydrophobic potential binding sites. The aim of this review was to investigate the spectrum of AAT molecular interactions, with newer studies supporting a potential therapeutic paradigm for AAT augmentation therapy in disorders in which a chronic immune response is strongly linked.

The causal relationship between circulating cytokines and critically ill COVID-19: A bidirectional Mendelian randomization analysis

Background

In this study, we performed a bidirectional mendelian randomization analysis on circulating cytokines and critically ill COVID-19.

Methods

Both the exposure and outcome data were obtained from public genome wide association study (GWAS) database. We extracted independent instrumental variables from exposure at genome level significance (P < 5 × 10⁻⁸). Wald ratio or inverse variance weighted (IVW) method were used for estimating the causal relationships between circulating cytokines and critically ill COVID-19.

Results

Only IL5 (cytokines to critically ill COVID-19 direction) and bNGF, IL8 (critically ill COVID-19 to cytokines direction) showed suggestive causal relations. However, these associations lost significance after FDR correction. Another validation data set of critically ill COVID-19 did not confirm these associations, either.

Conclusions

Our Mendelian randomization did not find causal relationships between analyzable circulating cytokines and critically ill COVID-19.

Using a Systems Approach to Explore the Mechanisms of Interaction Between Severe Covid-19 and Its Coronary Heart Disease Complications

Frontiers requested research on how a systems approach can explore the mechanisms of cardiovascular complications in Covid-19. The focus of this paper will thus be on these detailed mechanisms. It will elucidate the integrated pathogenic pathways based on an extensive review of literature. Many severe Covid-19 cases and deaths occur in patients with chronic cardiovascular comorbidities. To help understand all the mechanisms of this interaction, Covid-19 complications were integrated into a pre-existing systems-based coronary heart disease (CHD) model. Such a complete model could not be found in literature. A fully integrative view could be valuable in identifying new pharmaceutical interventions, help understand how health factors influence Covid-19 severity and give a fully integrated explanation for the Covid-19 death spiral phenomenon seen in some patients. Covid-19 data showed that CHD hallmarks namely, Hypercoagulability, Hypercholesterolemia, Hyperglycemia/Hyperinsulinemia, Inflammation and Hypertension have an important effect on disease severity. The pathogenic pathways that Covid-19 activate in CHD were integrated into the CHD model. This fully integrated model presents a visual explanation of the mechanism of interaction between CHD and Covid-19 complications. This includes a detailed integrated explanation of the death spiral as a result of interactions between Inflammation, endothelial cell injury, Hypercoagulability and hypoxia. Additionally, the model presents the aggravation of this death spiral through the other CHD hallmarks namely, Hyperglycemia/Hyperinsulinemia, Hypercholesterolemia, and/or Hypertension. The resulting model further suggests systematically how the pathogenesis of nine health factors (stress, exercise, smoking, etc.) and seven pharmaceutical interventions (statins, salicylates, thrombin inhibitors, etc.) may either aggravate or suppress Covid-19 severity. A strong association between CHD and Covid-19 for all the investigated health factors and pharmaceutical interventions, except for β-blockers, was found. It is further discussed how the proposed model can be extended in future to do computational analysis to help assess the risk of Covid-19 in cardiovascular disease. With insight gained from this study, recommendations are made for future research in potential new pharmacotherapeutics. These recommendations could also be beneficial for cardiovascular disease, which killed five times more people in the past year than Covid-19.

Tacrolimus Treatment for Post-COVID-19 Interstitial Lung Disease

With expansion of the COVID-19 pandemic, reports of post-COVID-19 interstitial lung disease (ILD) have been emerging. However, there are few reports regarding treatment. Some reports indicate that corticosteroids are effective for post-COVID-19 ILD, but the use of long-term corticosteroid carries risks of side effects. We administered tacrolimus to an elderly patient with post-COVID-19 ILD who suffered a respiratory failure relapse during steroid tapering. The respiratory status improved with tacrolimus in the post-acute phase, but pulmonary fibrosis progressed in the late phase. Tacrolimus may be effective for treating post-COVID-19 ILD in the post-acute phase, but it does not halt progression of pulmonary fibrosis.

Cytokine Elevation in Severe COVID-19 From Longitudinal Proteomics Analysis: Comparison With Sepsis

Introduction

Coronavirus disease 2019 (COVID-19) is a new viral disease. Uncontrolled inflammation called “cytokine storm” is reported to contribute to disease pathogenesis as well as sepsis. We aimed to identify cytokines related to the pathogenesis of COVID-19 through a proteomics analysis of 1463 plasma proteins, validate these cytokines, and compare them with sepsis.

Materials and Methods

In a derivation cohort of 306 patients with COVID-19, 1463 unique plasma proteins were measured on days 1, 4, and 8. Cytokines associated with disease severity and prognosis were derived. In a validation cohort of 62 COVID-19 patients and 38 sepsis patients treated in the intensive care unit [ICU], these derived cytokines were measured on days 1 (day of ICU admission), 2-3, and 6-8 (maximum: 3 time points/patient). Derived cytokines were compared with healthy controls and between COVID-19 and sepsis patients, and the associations with prognosis were evaluated. The time to wean off mechanical ventilation (MV) was evaluated only for COVID-19.

Results

IL-6, amphiregulin, and growth differentiation factor (GDF)-15 were associated with disease severity and prognosis in the derivation cohort. In the validation cohort, IL-6 and GDF-15 were elevated in COVID-19 and sepsis on day 1, and the levels of these cytokines were higher in sepsis than in COVID-19. IL-6 and GDF-15 were associated with prognosis in sepsis. Cox proportional hazards model with time as a dependent covariate showed a significant relationship between plasma GDF-15 level and time to wean off MV (hazard ratio, 0.549 [95% confidence level, 0.382–0.789]). The GDF-15 level at ICU admission predicted late recovery.

Conclusion

GDF-15 and IL-6 derived from proteomics analysis were related with disease severity of COVID-19. Their values were higher in sepsis than in COVID-19 and were associated with prognosis in sepsis. In COVID-19 patients treated in the ICU, GDF-15 was associated with the time to wean off MV and better predicted late recovery.

The Role of Interleukin-8 in Lung Inflammation and Injury: Implications for the Management of COVID-19 and Hyperinflammatory Acute Respiratory Distress Syndrome

Severe Acute Respiratory Syndrome Coronavirus—2 (SARS CoV-2) has resulted in the global spread of Coronavirus Disease 2019 (COVID-19) and an increase in complications including Acute Respiratory Distress Syndrome (ARDS). Due to the lack of therapeutic options for Acute Respiratory Distress Syndrome, recent attention has focused on differentiating hyper- and hypo-inflammatory phenotypes of ARDS to help define effective therapeutic strategies. Interleukin 8 (IL-8) is a pro-inflammatory cytokine that has a role in neutrophil activation and has been identified within the pathogenesis and progression of this disease. The aim of this review is to highlight the role of IL-8 as a biomarker and prognostic factor in modulating the hyperinflammatory response in ARDS. The crucial role of IL-8 in lung inflammation and disease pathogenesis might suggest IL-8 as a possible new therapeutic target to efficiently modulate the hyperinflammatory response in ARDS.

Skeletal muscle alterations in patients with acute Covid-19 and post-acute sequelae of Covid-19

Skeletal muscle-related symptoms are common in both acute coronavirus disease (Covid)-19 and post-acute sequelae of Covid-19 (PASC). In this narrative review, we discuss cellular and molecular pathways that are affected and consider these in regard to skeletal muscle involvement in other conditions, such as acute respiratory distress syndrome, critical illness myopathy, and post-viral fatigue syndrome. Patients with severe Covid-19 and PASC suffer from skeletal muscle weakness and exercise intolerance. Histological sections present muscle fibre atrophy, metabolic alterations, and immune cell infiltration. Contributing factors to weakness and fatigue in patients with severe Covid-19 include systemic inflammation, disuse, hypoxaemia, and malnutrition. These factors also contribute to post-intensive care unit (ICU) syndrome and ICU-acquired weakness and likely explain a substantial part of Covid-19-acquired weakness. The skeletal muscle weakness and exercise intolerance associated with PASC are more obscure. Direct severe acute respiratory syndrome coronavirus (SARS-CoV)-2 viral infiltration into skeletal muscle or an aberrant immune system likely contribute. Similarities between skeletal muscle alterations in PASC and chronic fatigue syndrome deserve further study. Both SARS-CoV-2-specific factors and generic consequences of acute disease likely underlie the observed skeletal muscle alterations in both acute Covid-19 and PASC.

Cellular metabolic basis of altered immunity in the lungs of patients with COVID-19

Metabolic pathways drive cellular behavior. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes lung tissue damage directly by targeting cells or indirectly by producing inflammatory cytokines. However, whether functional alterations are related to metabolic changes in lung cells after SARS-CoV-2 infection remains unknown. Here, we analyzed the lung single-nucleus RNA-sequencing (snRNA-seq) data of several deceased COVID-19 patients and focused on changes in transcripts associated with cellular metabolism. We observed upregulated glycolysis and oxidative phosphorylation in alveolar type 2 progenitor cells, which may block alveolar epithelial differentiation and surfactant secretion. Elevated inositol phosphate metabolism in airway progenitor cells may promote neutrophil infiltration and damage the lung barrier. Further, multiple metabolic alterations in the airway goblet cells are associated with impaired muco-ciliary clearance. Increased glycolysis, oxidative phosphorylation, and inositol phosphate metabolism not only enhance macrophage activation but also contribute to SARS-CoV-2 induced lung injury. The cytotoxicity of natural killer cells and CD8⁺ T cells may be enhanced by glycerolipid and inositol phosphate metabolism. Glycolytic activation in fibroblasts is related to myofibroblast differentiation and fibrogenesis. Glycolysis, oxidative phosphorylation, and glutathione metabolism may also boost the aging, apoptosis and proliferation of vascular smooth muscle cells, resulting in pulmonary arterial hypertension. In conclusion, this preliminary study revealed a possible cellular metabolic basis for the altered innate immunity, adaptive immunity, and niche cell function in the lung after SARS-CoV-2 infection. Therefore, patients with COVID-19 may benefit from therapeutic strategies targeting cellular metabolism in future.

Integrated histopathological, lipidomic, and metabolomic profiles reveal mink is a useful animal model to mimic the pathogenicity of severe COVID-19 patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted on mink farms between minks and humans in many countries. However, the systemic pathological features of SARS-CoV-2-infected minks are mostly unknown. Here, we demonstrated that minks were largely permissive to SARS-CoV-2, characterized by severe and diffuse alveolar damage, and lasted at least 14 days post inoculation (dpi). We first reported that infected minks displayed multiple organ-system lesions accompanied by an increased inflammatory response and widespread viral distribution in the cardiovascular, hepatobiliary, urinary, endocrine, digestive, and immune systems. The viral protein partially co-localized with activated Mac-2⁺ macrophages throughout the body. Moreover, we first found that the alterations in lipids and metabolites were correlated with the histological lesions in infected minks, especially at 6 dpi, and were similar to that of patients with severe and fatal COVID-19. Particularly, altered metabolic pathways, abnormal digestion, and absorption of vitamins, lipids, cholesterol, steroids, amino acids, and proteins, consistent with hepatic dysfunction, highlight metabolic and immune dysregulation. Enriched kynurenine in infected minks contributed to significant activation of the kynurenine pathway and was related to macrophage activation. Melatonin, which has significant anti-inflammatory and immunomodulating effects, was significantly downregulated at 6 dpi and displayed potential as a targeted medicine. Our data first illustrate systematic analyses of infected minks to recapitulate those observations in severe and fetal COVID-19 patients, delineating a useful animal model to mimic SARS-CoV-2-induced systematic and severe pathophysiological features and provide a reliable tool for the development of effective and targeted treatment strategies, vaccine research, and potential biomarkers.

Cardiovascular Risk After SARS-CoV-2 Infection Is Mediated by IL18/IL18R1/HIF-1 Signaling Pathway Axis

Objectives

Currently, cardiovascular risk associated with COVID-19 has been brought to people's attention, but the mechanism is not clear. The aim of this study is to elucidate the mechanisms based on multiple omics data.

Methodology

Weighted gene co-expression network analysis (WGCNA) was used to identify key pathways. Combination analysis with aneurysm and atherosclerosis related pathways, hypoxia induced factor-1 (HIF-1) signaling were identified as key pathways of the increased cardiovascular risk associated with COVID-19. ScMLnet algorithm based on scRNA-seq was used to explore the regulation of HIF-1 pathway by intercellular communication. Proteomic analysis was used to detect the regulatory mechanisms between IL18 and HIF-1 signaling pathway. Pseudo time locus analysis was used to study the regulation of HIF1 signaling pathway in macrophages and vascular smooth muscle cells (VSMC) phenotypic transformation. The Virtual Inference of protein-activity by Enriched Regulon (VIPER) analysis was used to study the activity of regulatory proteins. Epigenetic analysis based on methylation revealed epigenetic changes in PBMC after SARS-CoV-2 infection. Potential therapeutic compounds were explored by using Cmap algorithm.

Results

HIF-1 signaling pathway is a common key pathway for aneurysms, atherosclerosis and SARS-CoV-2 infection. Intercellular communication analysis showed that macrophage-derived interleukin-18 (IL-18) activates the HIF-1 signaling pathway through IL18R1. Proteomic analysis showed that IL18/IL18R1 promote NF-κB entry into the nucleus, and activated the HIF-1 signaling pathway. Macrophage-derived IL18 promoted the M1 polarization of macrophages and the syntactic phenotype transformation of VSMCs. MAP2K1 mediates the functional regulation of HIF-1 signaling pathway in various cell types. Epigenetic changes in PBMC after COVID-19 infection are characterized by activation of the type I interferon pathway. MEK inhibitors are the promising compounds for the treatment of HIF-1 overactivation.

Conclusions

The IL18/IL18R1/HIF1A axis is expected to be an therapeutic target for cardiovascular protection after SARS-CoV-2 infection. MEK inhibitors may be an choice for cardiovascular protection after SARS-COV-2 infection.

The Transmembrane Protease TMPRSS2 as a Therapeutic Target for COVID-19 Treatment

TMPRSS2 is a type II transmembrane protease with broad expression in epithelial cells of the respiratory and gastrointestinal tract, the prostate, and other organs. Although the physiological role of TMPRSS2 remains largely elusive, several endogenous substrates have been identified. TMPRSS2 serves as a major cofactor in SARS-CoV-2 entry, and primes glycoproteins of other respiratory viruses as well. Consequently, inhibiting TMPRSS2 activity is a promising strategy to block viral infection. In this review, we provide an overview of the role of TMPRSS2 in the entry processes of different respiratory viruses. We then review the different classes of TMPRSS2 inhibitors and their clinical development, with a focus on COVID-19 treatment.

Preclinical pharmacokinetics and safety of intravenous RTD-1

Severe illness caused by coronavirus disease 2019 (COVID-19) is characterized by an overexuberant inflammatory response resulting in acute respiratory distress syndrome (ARDS) and progressive respiratory failure (A. Gupta, M. V. Madhavan, K. Sehgal, N. Nair, et al., Nat Med 26:1017–1032, 2020, https://doi.org/10.1038/s41591-020-0968-3). Rhesus theta (θ) defensin-1 (RTD-1) is a macrocyclic host defense peptide exhibiting antimicrobial and immunomodulatory activities. RTD-1 treatment significantly improved survival in murine models of a severe acute respiratory syndrome (SARS-CoV-1) and endotoxin-induced acute lung injury (ALI) (C. L. Wohlford-Lenane, D. K. Meyerholz, S. Perlman, H. Zhou, et al., J Virol 83:11385–11390, 2009, https://doi.org/10.1128/JVI.01363-09; J. G. Jayne, T. J. Bensman, J. B. Schaal, A. Y. J. Park, et al., Am J Respir Cell Mol Biol 58:310–319, 2018, https://doi.org/10.1165/rcmb.2016-0428OC). This investigation aimed to characterize the preclinical pharmacokinetics (PK) and safety of intravenous (i.v.) RTD-1. Based on the lack of adverse findings, the no observed adverse effect level (NOAEL) was established at 10 mg/kg/day in rats and 15 mg/kg/day in monkeys. Analysis of single ascending dose studies in both species revealed greater-than-dose-proportional increases in the area under the curve extrapolated to infinity (AUC_0-∞) (e.g., 8-fold increase from 5 mg/kg to 20 mg/kg in rats) suggestive of nonlinear PK. The volume of distribution at steady state (V_ss) ranged between 550 and 1,461 mL/kg, indicating extensive tissue distribution, which was validated in a biodistribution study of [¹⁴C]RTD-1 in rats. Based on interspecies allometric scaling, the predicted human clearance and V_ss are 6.48 L/h and 28.0 L, respectively, for an adult (70 kg). To achieve plasma exposures associated with therapeutic efficacy established in a murine model of ALI, the estimated human equivalent dose (HED) is between 0.36 and 0.83 mg/kg/day. The excellent safety profile demonstrated in these studies and the efficacy observed in the murine models support the clinical investigation of RTD-1 for treatment of COVID-19 or other pulmonary inflammatory diseases.

Interrelationship between 2019-nCov receptor DPP4 and diabetes mellitus targets based on protein interaction network

Patients with diabetes are more likely to be infected with Coronavirus disease 2019 (COVID-19), and the risk of death is significantly higher than ordinary patients. Dipeptidyl peptidase-4 (DPP4) is one of the functional receptor of human coronavirus. Exploring the relationship between diabetes mellitus targets and DPP4 is particularly important for the management of patients with diabetes and COVID-19. We intend to study the protein interaction through the protein interaction network in order to find a new clue for the management of patients with diabetes with COVID-19. Diabetes mellitus targets were obtained from GeneCards database. Targets with a relevance score exceeding 20 were included, and DPP4 protein was added manually. The initial protein interaction network was obtained through String. The targets directly related to DPP4 were selected as the final analysis targets. Importing them into String again to obtain the protein interaction network. Module identification, gene ontology (GO) analysis and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis were carried out respectively. The impact of DPP4 on the whole network was analyzed by scoring the module where it located. 43 DPP4-related proteins were finally selected from the diabetes mellitus targets and three functional modules were found by the cluster analysis. Module 1 was involved in insulin secretion and glucagon signaling pathway, module 2 and module 3 were involved in signaling receptor binding. The scoring results showed that LEP and apoB in module 1 were the highest, and the scores of INS, IL6 and ALB of cross module associated proteins of module 1 were the highest. DPP4 is widely associated with key proteins in diabetes mellitus. COVID-19 may affect DPP4 in patients with diabetes mellitus, leading to high mortality of diabetes mellitus combined with COVID-19. DPP4 inhibitors and IL-6 antagonists can be considered to reduce the effect of COVID-19 infection on patients with diabetes.

Innate immunological pathways in COVID-19 pathogenesis

[Figure: see text].

A virus-specific monocyte inflammatory phenotype is induced by SARS-CoV-2 at the immune-epithelial interface

By modeling in vitro the cross-talk between epithelial and immune cells, this work provides possible origins for the profound inflammatory perturbations that are a hallmark of COVID-19, and the relative protection of children from severe disease. The initial interaction between immune cells and epithelial cells infected with SARS-CoV-2, or transduced to express the proteins the virus encodes, elicits a specific response, not observed with other pathogenic viruses, that presages perturbations seen in patients with severe COVID-19. Thus, the severe manifestations of COVID-19 may be rooted in the very first response that it elicits from immunocytes.

Infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) provokes a potentially fatal pneumonia with multiorgan failure, and high systemic inflammation. To gain mechanistic insight and ferret out the root of this immune dysregulation, we modeled, by in vitro coculture, the interactions between infected epithelial cells and immunocytes. A strong response was induced in monocytes and B cells, with a SARS-CoV-2–specific inflammatory gene cluster distinct from that seen in influenza A or Ebola virus-infected cocultures, and which reproduced deviations reported in blood or lung myeloid cells from COVID-19 patients. A substantial fraction of the effect could be reproduced after individual transfection of several SARS-CoV-2 proteins (Spike and some nonstructural proteins), mediated by soluble factors, but not via transcriptional induction. This response was greatly muted in monocytes from healthy children, perhaps a clue to the age dependency of COVID-19. These results suggest that the inflammatory malfunction in COVID-19 is rooted in the earliest perturbations that SARS-CoV-2 induces in epithelia.