Mechanisms of severe acute respiratory syndrome coronavirus-induced acute lung injury

Aprotinin (II): Inhalational Administration for the Treatment of COVID-19 and Other Viral Conditions

Aprotinin is a broad-spectrum inhibitor of human proteases that has been approved for the treatment of bleeding in single coronary artery bypass surgery because of its potent antifibrinolytic actions. Following the outbreak of the COVID-19 pandemic, there was an urgent need to find new antiviral drugs. Aprotinin is a good candidate for therapeutic repositioning as a broad-spectrum antiviral drug and for treating the symptomatic processes that characterise viral respiratory diseases, including COVID-19. This is due to its strong pharmacological ability to inhibit a plethora of host proteases used by respiratory viruses in their infective mechanisms. The proteases allow the cleavage and conformational change of proteins that make up their viral capsid, and thus enable them to anchor themselves by recognition of their target in the epithelial cell. In addition, the activation of these proteases initiates the inflammatory process that triggers the infection. The attraction of the drug is not only its pharmacodynamic characteristics but also the possibility of administration by the inhalation route, avoiding unwanted systemic effects. This, together with the low cost of treatment (≈2 Euro/dose), makes it a good candidate to reach countries with lower economic means. In this article, we will discuss the pharmacodynamic, pharmacokinetic, and toxicological characteristics of aprotinin administered by the inhalation route; analyse the main advances in our knowledge of this medication; and the future directions that should be taken in research in order to reposition this medication in therapeutics.

Disseminated intravascular coagulation is associated with poor prognosis in patients with COVID-19

This study aimed to investigate the incidence and significance of disseminated intravascular coagulation (DIC) in coronavirus disease 2019 (COVID-19). A multicenter cohort study was conducted using large-scale COVID-19 registry data. The patients were classified into DIC and non-DIC groups based on the diagnosis on admission (day 1) and on any of the days 1, 4, 8, and 15. In total, 23,054 patients were divided into DIC (n = 264) and non-DIC (n = 22,790) groups on admission. Thereafter, 1654 patients were divided into 181 patients with DIC and 1473 non-DIC patients based on the DIC diagnosis on any of the days from 1 to 15. DIC incidence was 1.1% on admission, increasing to 10.9% by day 15. DIC diagnosis on admission had moderate predictive performance for developing multiple organ dysfunction syndrome (MODS) on day 4 and in-hospital death and was independently associated with MODS and in-hospital death. DIC diagnosis on any of the days from 1 to 15, especially days 8 and 15, was associated with lower survival probability than those without DIC and showed significant association with in-hospital death. In conclusion, despite its low incidence, DIC, particularly late-onset DIC, plays a significant role in the pathogenesis of poor prognosis in patients with COVID-19.

Odds and associated factors for thrombosis development among Lebanese COVID-19 patients: a case-control retrospective study

Background

Thromboembolism is reported to be up to 27% in COVID-19 patients due to SARS-CoV-2 infection. Dysregulated systemic inflammation and various patient traits play a vital role in thrombosis progression.

Purpose

To assess odds and associated factors for thrombosis development among Lebanese COVID-19 patients.

Methods

This was a case-control retrospective study conducted in January-May 2021. Patients infected with COVID-19 and developed thrombosis were classified as cases and patients who were thrombosis-free identified as control. A questionnaire assessed socio-demographics, clinical parameters, and WHO COVID-19 disease severity.

Results

Among 267 patients, 26 (9.7%) developed thrombosis and the majority of thrombosis 34.6% was myocardial infarction, and the least (3.8%) was for catheter-related thrombosis. Results showed that the risk of thrombosis development is higher in patients with previous thromboembolic event (OR = 9.160) and previous intake of anti-hypertensive medications at home (OR = 3.116). However, females (OR = 0.330; CI: 0.118-0.925), intake of anticoagulants during hospital admission (OR = 0.126; CI: 0.053-0.300) and non-severe COVID-19 were at lower thrombosis risk (OR = 0.273). Patients who developed thromboembolic events had longer hospital stay (OR = 0.077).

Conclusion

Patients with COVID-19 and thromboembolism were at higher risk of mortality as compared to patients with COVID-19 but without thromboembolism. The use of anticoagulants significantly reduced the risk for thromboembolism.

Extracellular Vesicles in Transplantation: Friend or Foe

The long-term function of transplanted organs, even under immunosuppression, is hindered by rejection, especially chronic rejection. Chronic rejection occurs more frequently after lung transplantation, termed chronic lung allograft dysfunction (CLAD), than after transplantation of other solid organs. Pulmonary infection is a known risk factor for CLAD, as transplanted lungs are constantly exposed to the external environment; however, the mechanisms by which respiratory infections lead to CLAD are poorly understood. The role of extracellular vesicles (EVs) in transplantation remains largely unknown. Current evidence suggests that EVs released from transplanted organs can serve as friend and foe. EVs carry not only major histocompatibility complex antigens but also tissue-restricted self-antigens and various transcription factors, costimulatory molecules, and microRNAs capable of regulating alloimmune responses. EVs play an important role in antigen presentation by direct, indirect, and semidirect pathways in which CD8 and CD4 cells can be activated. During viral infections, exosomes (small EVs <200 nm in diameter) can express viral antigens and regulate immune responses. Circulating exosomes may also be a viable biomarker for other diseases and rejection after organ transplantation. Bioengineering the surface of exosomes has been proposed as a tool for targeted delivery of drugs and personalized medicine. This review focuses on recent studies demonstrating the role of EVs with a focus on exosomes and their dual role (immune activation or tolerance induction) after organ transplantation, more specifically, lung transplantation.

Comparative Pathogenesis of Severe Acute Respiratory Syndrome Coronaviruses

Over the last two decades the world has witnessed the global spread of two genetically related highly pathogenic coronaviruses, severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2. However, the impact of these outbreaks differed significantly with respect to the hospitalizations and fatalities seen worldwide. While many studies have been performed recently on SARS-CoV-2, a comparative pathogenesis analysis with SARS-CoV may further provide critical insights into the mechanisms of disease that drive coronavirus-induced respiratory disease. In this review, we comprehensively describe clinical and experimental observations related to transmission and pathogenesis of SARS-CoV-2 in comparison with SARS-CoV, focusing on human, animal, and in vitro studies. By deciphering the similarities and disparities of SARS-CoV and SARS-CoV-2, in terms of transmission and pathogenesis mechanisms, we offer insights into the divergent characteristics of these two viruses. This information may also be relevant to assessing potential novel introductions of genetically related highly pathogenic coronaviruses.

Identification of genomic loci regulating platelet plasminogen activator inhibitor-1 in mice

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1, Serpine1) is an important circulating fibrinolysis inhibitor. PAI-1 exists in 2 pools, packaged within platelet α-granules and freely circulating in plasma. Elevated plasma PAI-1 levels are associated with cardiovascular disease. However, little is known about the regulation of platelet PAI-1 (pPAI-1).

OBJECTIVES

We investigated the genetic control of pPAI-1 levels in mice and humans.

METHODS

We measured pPAI-1 antigen levels via enzyme-linked immunosorbent assay in platelets isolated from 10 inbred mouse strains, including LEWES/EiJ (LEWES) and C57BL/6J (B6). LEWES and B6 were crossed to produce the F1 generation, B6LEWESF1. B6LEWESF1 mice were intercrossed to produce B6LEWESF2 mice. These mice were subjected to genome-wide genetic marker genotyping followed by quantitative trait locus analysis to identify pPAI-1 regulatory loci.

RESULTS

We identified differences in pPAI-1 between several laboratory strains, with LEWES having pPAI-1 levels more than 10-fold higher than those in B6. Quantitative trait locus analysis of B6LEWESF2 offspring identified a major pPAI-1 regulatory locus on chromosome 5 from 136.1 to 137.6 Mb (logarithm of the odds score, 16.2). Significant pPAI-1 modifier loci on chromosomes 6 and 13 were also identified.

CONCLUSION

Identification of pPAI-1 genomic regulatory elements provides insights into platelet/megakaryocyte-specific and cell type-specific gene expression. This information can be used to design more precise therapeutic targets for diseases where PAI-1 plays a role.

Thromboelastometry-Guided Individualized Fibrinolytic Treatment for COVID-19-Associated Severe Coagulopathy Complicated by Portal Vein Thrombosis: A Case Report

COVID-19-associated coagulopathy (CAC), mainly characterized by hypercoagulability leading to micro- and macrovascular thrombotic events due to the fibrinolysis shutdown phenomenon, is a life-threatening complication of severe SARS-CoV-2 infection. However, optimal criteria to assess patients with the highest risk for progression of severe CAC are still unclear. Bedside point-of-care viscoelastic testing (VET) appears to be a promising tool to recognize CAC, to support the appropriate therapeutic decisions, and to monitor the efficacy of the treatment. The ClotPro VET has the potential to reveal fibrinolysis resistance indicated by a clot lysis time (LT) > 300 s on the TPA-test. We present a case of severe SARS-CoV-2 infection complicated by CAC-resulting portal vein thrombosis (PVT) and subsequent liver failure despite therapeutic anticoagulation. Since fibrinolysis shutdown (LT > 755 s) caused PVT, we performed a targeted systemic fibrinolytic therapy. We monitored the efficacy of the treatment with repeated TPA assays every three hours, while the dose of recombinant plasminogen activator (rtPA) was adjusted until fibrinolysis shutdown completely resolved and portal vein patency was confirmed by an ultrasound examination. Our case report highlights the importance of VET-guided personalized therapeutic approach during the care of severely ill COVID-19 patients, in order to appropriately treat CAC.

Monitoring the Coagulation Profile of COVID-19 Patients Using Standard and ClotPro® Hemostasis Tests

Background and Objectives: Coagulation disorders during COVID-19 infection are associated with a poorer prognosis and higher disease severity because thrombosis and inflammation are two processes that interfere with each other. A very important issue for clinicians is timely and adequate hemostasis and inflammation monitoring to prevent and treat potentially lethal consequences. The aim of this study was to identify specific hemostatic parameters that are associated with a higher risk of intrahospital mortality. Materials and Methods: This study was approved by the Ethics Committee of the Clinical Center Nis in Serbia. One hundred and forty-two patients presented with COVID-19 ARDS and were admitted to the ICU in the Clinic for Anesthesiology at the Clinical Center Nis from 14 April 2020 to 25 May 2020. Upon admission, blood was collected for biochemical and coagulation testing. The data obtained were analyzed using the Statistical Package for Social Sciences (SPSS v. 25, Chicago, IL, USA). Results: Among all the parameters assessed, older age; increased levels of fibrinogen, INR, D-dimer, and presepsin; and higher results in the platelet aggregation tests (aggregation induced by adenosine diphosphate based on the ADP test (AU/min), aggregation induced by arachidonic acid based on the ASPI test (AU/min), and aggregation induced by thrombin based on the TRAP test (AU/min)) and some assays of the viscoelastic test (clot amplitude after 5 min in the extrinsic coagulation pathway based on the A5 EX-test (mm), clot amplitude after 10 min in the extrinsic coagulation pathway based on the A10 EX-test (mm), clot amplitude after 5 min regarding functional fibrinogen based on the A5 FIB-test (mm), clot amplitude after 10 min regarding functional fibrinogen based on the A10 FIB-test (mm), and maximum clot firmness based on the MCF FIB-test (mm)); and lower values of viscoelastic clotting time in the extrinsic coagulation pathway based on the CT EX-test (s) were significantly correlated with mortality. In the multivariate analysis, D-dimer levels above 860 ng/mL, higher TRAP test value bins, and values above the normal reference range of the A10 FIB test were found to be independent predictors of mortality. Conclusions: Sophisticated hemostasis parameters can contribute to early risk assessment, which has initially been performed only on the basis of patients' clinical status. Hypercoagulability is the main coagulation disorder in COVID-19 infection.

Effects of COVID-19 disease on PAI-1 antigen and haematological parameters during disease management: A prospective cross-sectional study in a regional Hospital in Ghana

BACKGROUND

Individuals with COVID-19 experience thrombotic events probably due to the associated hypofibrinolysis resulting from the upregulation of plasminogen activator inhibitor-1 (PAI-1) antigen. This study evaluated plasma PAI-1 antigen levels and haematological parameters before treatment and after recovery from severe COVID-19 in Ghana.

MATERIALS AND METHODS

This cross-sectional study was conducted at Sunyani Regional Hospital, and recruited 51 patients who had RT-PCR-confirmed SARS-CoV-2. Participants' sociodemographic data and clinical characteristics were taken from the hospital records. Venous blood was taken before COVID-19 treatment commenced for FBC, PAI-1 and ferritin assays. FBC was assessed using an automated haematology analyzer, whilst plasma PAI-1 Ag and serum ferritin levels were assessed with sandwich ELISA. All the tests were repeated immediately after participants recovered from COVID-19.

RESULTS

Of the 51 participants recruited into the study, 78.4% (40) had non-severe COVID-19 whiles 21.6% (11) experienced a severe form of the disease. Severe COVID-19 participants had significantly lower haemoglobin (g/dL): 8.1 (7.3-8.4) vs 11.8 (11.0-12.5), p<0.001; RBC x 1012/L: 2.9 (2.6-3.1) vs 3.4 (3.1-4.3), p = 0.001; HCT%: 24.8 ± 2.6 vs 35.3 ± 6.7, p<0.001 and platelet x 109/L: 86.4 (62.2-91.8) vs 165.5 (115.1-210.3), p<0.001, compared with the non-severe COVID-19 group. But WBC x 109/L: 11.6 (9.9-14.2) vs 5.4 (3.7-6.6), p<0.001 and ferritin (ng/mL): 473.1 (428.3-496.0) vs 336.2 (249.9-386.5), p<0.001, were relatively higher in the participants with severe COVID-19 than the non-severe COVID-19 counterparts. Also, the severely ill SARS-CoV-2-infected participants had relatively higher plasma PAI-1 Ag levels (ng/mL): 131.1 (128.7-131.9) vs 101.3 (92.0-116.8), p<0.001, than those with the non-severe form of the disease. Participants had lower haemoglobin (g/dL): 11.4 (8.8-12.3 vs 12.4 (11.5-13.6), p<0.001; RBC x 1012/L: 3.3 (2.9-4.0) vs 4.3 (3.4-4.6), p = 0.001; absolute granulocyte count x 109/L: 2.3 ± 1.0 vs 4.6 ± 1.8, p<0.001, and platelet x 109/L: 135.0 (107.0-193.0) vs 229.0 (166.0-270.0), p<0.001 values at admission before treatment commenced, compared to when they recovered from the disease. Additionally, the median PAI-1 Ag (ng/mL): 89.6 (74.9-100.8) vs 103.1 (93.2-128.7), p<0.001 and ferritin (ng/mL): 242.2 (197.1-302.1) vs 362.3 (273.1-399.9), p<0.001 levels were reduced after a successful recovery from COVID-19 compared to the values at admission.

CONCLUSION

Plasma PAI-1 Ag level was higher among severe COVID-19 participants. The COVID-19-associated inflammation could affect red blood cell parameters and platelets. Successful recovery from COVID-19, with reduced inflammatory response as observed in the decline of serum ferritin levels restores the haematological parameters. Plasma levels of PAI-1 should be assessed during the management of severe COVID-19 in Ghana. This will enhance the early detection of probable thrombotic events and prompts Physicians to provide interventions to prevent thrombotic complications associated with COVID-19.

All tangled up: interactions of the fibrinolytic and innate immune systems

The hemostatic and innate immune system are intertwined processes. Inflammation within the vasculature promotes thrombus development, whilst fibrin forms part of the innate immune response to trap invading pathogens. The awareness of these interlinked process has resulted in the coining of the terms "thromboinflammation" and "immunothrombosis." Once a thrombus is formed it is up to the fibrinolytic system to resolve these clots and remove them from the vasculature. Immune cells contain an arsenal of fibrinolytic regulators and plasmin, the central fibrinolytic enzyme. The fibrinolytic proteins in turn have diverse roles in immunoregulation. Here, the intricate relationship between the fibrinolytic and innate immune system will be discussed.

Interrelationship between COVID-19 and Coagulopathy: Pathophysiological and Clinical Evidence

Since the first description of COVID-19 infection, among clinical manifestations of the disease, including fever, dyspnea, cough, and fatigue, it was observed a high incidence of thromboembolic events potentially evolving towards acute respiratory distress syndrome (ARDS) and COVID-19-associated-coagulopathy (CAC). The hypercoagulation state is based on an interaction between thrombosis and inflammation. The so-called CAC represents a key aspect in the genesis of organ damage from SARS-CoV-2. The prothrombotic status of COVID-19 can be explained by the increase in coagulation levels of D-dimer, lymphocytes, fibrinogen, interleukin 6 (IL-6), and prothrombin time. Several mechanisms have been hypothesized to explain this hypercoagulable process such as inflammatory cytokine storm, platelet activation, endothelial dysfunction, and stasis for a long time. The purpose of this narrative review is to provide an overview of the current knowledge on the pathogenic mechanisms of coagulopathy that may characterize COVID-19 infection and inform on new areas of research. New vascular therapeutic strategies are also reviewed.

Cardiopulmonary Phenotypes of Post Acute Sequelae of Severe Acute Respiratory Syndrome Coronavirus 2: A Narrative Review

The acute effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are well known; however, the long-term cardiopulmonary effects are less well characterized. The phenotypic expression of acute infection is heterogeneous, ranging from a complete absence of symptoms to shock, multisystem organ failure, and death. Patients with severe or critical coronavirus disease (COVID-19) who survive their initial illness can require a prolonged period of recovery lasting weeks to months. This specific patient group is part of a larger and even more heterogeneous group of patients who initially experience mild-to-moderate symptoms that fail to resolve over time. Collectively, patients recovering from severe or critical COVID-19 and those who continue to experience symptoms following a lower acuity infection are considered to have Post Acute Sequalae of SARS-CoV-2 infection (PASC). Using prognostic factors like myocardial infarction, myocarditis, pulmonary embolism, acute respiratory distress syndrome, need for mechanical ventilation or extracorporeal membrane oxygenation, and advanced pharmaceutical therapies that primarily occur or are instituted in the acute phase of illness one can begin to develop a taxonomy or corpus of PASC in its varied forms.

Interferon-induced transmembrane protein 3 (IFITM3) limits lethality of SARS-CoV-2 in mice

Interferon-induced transmembrane protein 3 (IFITM3) is an antiviral protein that alters cell membranes to block fusion of viruses. Conflicting reports identified opposing effects of IFITM3 on SARS-CoV-2 infection of cells, and its impact on viral pathogenesis in vivo remains unclear. Here, we show that IFITM3 knockout (KO) mice infected with SARS-CoV-2 experience extreme weight loss and lethality compared to mild infection in wild-type (WT) mice. KO mice have higher lung viral titers and increases in inflammatory cytokine levels, immune cell infiltration, and histopathology. Mechanistically, we observe disseminated viral antigen staining throughout the lung and pulmonary vasculature in KO mice, as well as increased heart infection, indicating that IFITM3 constrains dissemination of SARS-CoV-2. Global transcriptomic analysis of infected lungs shows upregulation of gene signatures associated with interferons, inflammation, and angiogenesis in KO versus WT animals, highlighting changes in lung gene expression programs that precede severe lung pathology and fatality. Our results establish IFITM3 KO mice as a new animal model for studying severe SARS-CoV-2 infection and overall demonstrate that IFITM3 is protective in SARS-CoV-2 infections in vivo.

Past, Present, and Future Perspectives of Plasminogen Activator Inhibitor 1 (PAI-1)

Plasminogen activator inhibitor 1 (PAI-1), a SERPIN inhibitor, is primarily known for its regulation of fibrinolysis. However, it is now known that this inhibitor functions and contributes to many (patho)physiological processes including inflammation, wound healing, cell adhesion, and tumor progression.This review discusses the past, present, and future roles of PAI-1, with a particular focus on the discovery of this inhibitor in the 1970s and subsequent characterization in health and disease. Throughout the past few decades diverse functions of this serpin have unraveled and it is now considered an important player in many disease processes. PAI-1 is expressed by numerous cell types, including megakaryocytes and platelets, adipocytes, endothelial cells, hepatocytes, and smooth muscle cells. In the circulation PAI-1 exists in two pools, within plasma itself and in platelet α-granules. Platelet PAI-1 is secreted following activation with retention of the inhibitor on the activated platelet membrane. Furthermore, these anucleate cells contain PAI-1 messenger ribonucleic acid to allow de novo synthesis.Outside of the traditional role of PAI-1 in fibrinolysis, this serpin has also been identified to play important roles in metabolic syndrome, obesity, diabetes, and most recently, acute respiratory distress syndrome, including coronavirus disease 2019 disease. This review highlights the complexity of PAI-1 and the requirement to ascertain a better understanding on how this complex serpin functions in (patho)physiological processes.

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Tissue factor in COVID-19-associated coagulopathy

Evidence of micro- and macro-thrombi in the arteries and veins of critically ill COVID-19 patients and in autopsies highlight the occurrence of COVID-19-associated coagulopathy (CAC). Clinical findings of critically ill COVID-19 patients point to various mechanisms for CAC; however, the definitive underlying cause is unclear. Multiple factors may contribute to the prothrombotic state in patients with COVID-19. Aberrant expression of tissue factor (TF), an initiator of the extrinsic coagulation pathway, leads to thrombotic complications during injury, inflammation, and infections. Clinical evidence suggests that TF-dependent coagulation activation likely plays a role in CAC. Multiple factors could trigger abnormal TF expression and coagulation activation in patients with severe COVID-19 infection. Proinflammatory cytokines that are highly elevated in COVID-19 (IL-1β, IL-6 and TNF-α) are known induce TF expression on leukocytes (e.g. monocytes, macrophages) and non-immune cells (e.g. endothelium, epithelium) in other conditions. Antiphospholipid antibodies, TF-positive extracellular vesicles, pattern recognition receptor (PRR) pathways and complement activation are all candidate factors that could trigger TF-dependent procoagulant activity. In addition, coagulation factors, such as thrombin, may further potentiate the induction of TF via protease-activated receptors on cells. In this systematic review, with other viral infections, we discuss potential mechanisms and cell-type-specific expressions of TF during SARS-CoV-2 infection and its role in the development of CAC.

Understanding COVID-19-associated coagulopathy

COVID-19-associated coagulopathy (CAC) is a life-threatening complication of SARS-CoV-2 infection. However, the underlying cellular and molecular mechanisms driving this condition are unclear. Evidence supports the concept that CAC involves complex interactions between the innate immune response, the coagulation and fibrinolytic pathways, and the vascular endothelium, resulting in a procoagulant condition. Understanding of the pathogenesis of this condition at the genomic, molecular and cellular levels is needed in order to mitigate thrombosis formation in at-risk patients. In this Perspective, we categorize our current understanding of CAC into three main pathological mechanisms: first, vascular endothelial cell dysfunction; second, a hyper-inflammatory immune response; and last, hypercoagulability. Furthermore, we pose key questions and identify research gaps that need to be addressed to better understand CAC, facilitate improved diagnostics and aid in therapeutic development. Finally, we consider the suitability of different animal models to study CAC.

Hemostatic system and COVID-19 crosstalk: A review of the available evidence

Since the discovery of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its resultant coronavirus disease 2019 (COVID-19) pandemic, respiratory manifestations have been the mainstay of clinical diagnosis, laboratory evaluations, and radiological investigations. As time passed, other pathological aspects of SARS-CoV-2 have been revealed. Various hemostatic abnormalities have been reported since the rise of the pandemic, which was sometimes superficial, transient, or fatal. Mild thrombocytopenia, thrombocytosis, venous, arterial thromboembolism, and disseminated intravascular coagulation are among the many hemostatic events associated with COVID-19. Venous thromboembolism necessitating therapeutic doses of anticoagulants is more frequently seen in severe cases of COVID-19, especially in patients admitted to intensive care units. Hemorrhagic complications rarely arise in COVID-19 patients either due to a hemostatic imbalance resulting from severe disease or as a complication of over anticoagulation. Although the pathogenesis of coagulation disturbance in SARS-CoV-2 infection is not yet understood, professional societies recommend prophylactic antithrombotic therapy in severe cases, especially in the presence of abnormal coagulation indices. The review article discusses the various available evidence on coagulation disorders, management strategies, outcomes, and prognosis associated with COVID-19 coagulopathy, which raises awareness about the importance of anticoagulation therapy for COVID-19 patients to guard against possible thromboembolic events.

A multi-tissue study of immune gene expression profiling highlights the key role of the nasal epithelium in COVID-19 severity

Coronavirus Disease-19 (COVID-19) symptoms range from mild to severe illness; the cause for this differential response to infection remains unknown. Unravelling the immune mechanisms acting at different levels of the colonization process might be key to understand these differences. We carried out a multi-tissue (nasal, buccal and blood; n = 156) gene expression analysis of immune-related genes from patients affected by different COVID-19 severities, and healthy controls through the nCounter technology. Mild and asymptomatic cases showed a powerful innate antiviral response in nasal epithelium, characterized by activation of interferon (IFN) pathway and downstream cascades, successfully controlling the infection at local level. In contrast, weak macrophage/monocyte driven innate antiviral response and lack of IFN signalling activity were present in severe cases. Consequently, oral mucosa from severe patients showed signals of viral activity, cell arresting and viral dissemination to the lower respiratory tract, which ultimately could explain the exacerbated innate immune response and impaired adaptative immune responses observed at systemic level. Results from saliva transcriptome suggest that the buccal cavity might play a key role in SARS-CoV-2 infection and dissemination in patients with worse prognosis. Co-expression network analysis adds further support to these findings, by detecting modules specifically correlated with severity involved in the abovementioned biological routes; this analysis also provides new candidate genes that might be tested as biomarkers in future studies. We also found tissue specific severity-related signatures mainly represented by genes involved in the innate immune system and cytokine/chemokine signalling. Local immune response could be key to determine the course of the systemic response and thus COVID-19 severity. Our findings provide a framework to investigate severity host gene biomarkers and pathways that might be relevant to diagnosis, prognosis, and therapy.

Pathophysiology and Management of Hypercoagulation in Infectious Diseases

Numerous systemic infections may have hypercoagulation as one of the complications, which may range from asymptomatic presentation of elevation of biochemical markers of coagulation such as that of fibrin and thrombin generation, to a much severe, symptomatic, life-threatening, disseminated intravascular coagulation (DIC), which results in the formation of thrombi in the microvasculature of various organs. This phenomenon contributes to increase in morbidity and mortality in various infectious diseases. The current review discusses various mechanisms of hypercoagulation during infections such as tissue factor activation, endothelial cell activation, inhibition of physiological anticoagulant pathways, and fibrinolysis inhibition. The review also discusses pathophysiological changes in the coagulation system and its management in the recent pandemic of COVID-19. The article also discusses role of various parenteral and oral anticoagulants in the management of infectious diseases. The review provides clinical data on various anticoagulants used during hospitalization and extended prophylaxis for the management of venous thromboembolism in various infections.

Methodology Because this is a review of published literature and no humans or animals were involved, ethical committee approval was not required and patient consent was not required.

Mechanistic Understanding of Lung Inflammation: Recent Advances and Emerging Techniques

Acute respiratory distress syndrome (ARDS) is a life-threatening lung injury characterized by an acute inflammatory response in the lung parenchyma. Hence, it is considered as the most appropriate clinical syndrome to study pathogenic mechanisms of lung inflammation. ARDS is associated with increased morbidity and mortality in the intensive care unit (ICU), while no effective pharmacological treatment exists. It is very important therefore to fully characterize the underlying pathobiology and the related mechanisms, in order to develop novel therapeutic approaches. In vivo and in vitro models are important pre-clinical tools in biological and medical research in the mechanistic and pathological understanding of the majority of diseases. In this review, we will present data from selected experimental models of lung injury/acute lung inflammation, which have been based on clinical disorders that can lead to the development of ARDS and related inflammatory lung processes in humans, including ventilation-induced lung injury (VILI), sepsis, ischemia/reperfusion, smoke, acid aspiration, radiation, transfusion-related acute lung injury (TRALI), influenza, Streptococcus (S.) pneumoniae and coronaviruses infection. Data from the corresponding clinical conditions will also be presented. The mechanisms related to lung inflammation that will be covered are oxidative stress, neutrophil extracellular traps, mitogen-activated protein kinase (MAPK) pathways, surfactant, and water and ion channels. Finally, we will present a brief overview of emerging techniques in the field of omics research that have been applied to ARDS research, encompassing genomics, transcriptomics, proteomics, and metabolomics, which may recognize factors to help stratify ICU patients at risk, predict their prognosis, and possibly, serve as more specific therapeutic targets.

Prediction of coronavirus 3C-like protease cleavage sites using machine-learning algorithms

The coronavirus 3C-like (3CL) protease, a cysteine protease, plays an important role in viral infection and immune escape. However, there is still a lack of effective tools for determining the cleavage sites of the 3CL protease. This study systematically investigated the diversity of the cleavage sites of the coronavirus 3CL protease on the viral polyprotein, and found that the cleavage motif were highly conserved for viruses in the genera of Alphacoronavirus, Betacoronavirus and Gammacoronavirus. Strong residue preferences were observed at the neighboring positions of the cleavage sites. A random forest (RF) model was built to predict the cleavage sites of the coronavirus 3CL protease based on the representation of residues in cleavage motifs by amino acid indexes, and the model achieved an AUC of 0.96 in cross-validations. The RF model was further tested on an independent test dataset which were composed of cleavage sites on 99 proteins from multiple coronavirus hosts. It achieved an AUC of 0.95 and predicted correctly 80% of the cleavage sites. Then, 1,352 human proteins were predicted to be cleaved by the 3CL protease by the RF model. These proteins were enriched in several GO terms related to the cytoskeleton, such as the microtubule, actin and tubulin. Finally, a webserver named 3CLP was built to predict the cleavage sites of the coronavirus 3CL protease based on the RF model. Overall, the study provides an effective tool for identifying cleavage sites of the 3CL protease and provides insights into the molecular mechanism underlying the pathogenicity of coronaviruses.

COVID-19 associated coagulopathy and thrombosis in cancer

Cancer patients are at risk for a more severe COVID-19 infection as well as an adverse outcome of such infection. This may be caused by the cancer itself (e.g haematological malignancies and lung cancer) or due to immune suppression caused by anti-cancer treatment. Severe COVID-19 infections are often complicated by a coagulopathy that clinically results in a high incidence of venous thromboembolic disease. Cancer itself is associated with a hypercoagulable state and a markedly increased incidence of thromboembolic complications, hence the combination of cancer and COVID-19 may amplify this risk. COVID-19 vaccination seems safe and effective in most cancer patients although adapted and bespoke vaccination schemes may increase the seroconversion rate and immune response in selected patients. Specific management strategies to improve outcomes of cancer patients in COVID-19 (e.g. higher intensity antithrombotic prophylaxis) are lacking and should be evaluated in clinical studies simultaneously focusing on efficacy and safety.

SARS-CoV-2 pathogenesis

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a devastating pandemic. Although most people infected with SARS-CoV-2 develop a mild to moderate disease with virus replication restricted mainly to the upper airways, some progress to having a life-threatening pneumonia. In this Review, we explore recent clinical and experimental advances regarding SARS-CoV-2 pathophysiology and discuss potential mechanisms behind SARS-CoV-2-associated acute respiratory distress syndrome (ARDS), specifically focusing on new insights obtained using novel technologies such as single-cell omics, organoid infection models and CRISPR screens. We describe how SARS-CoV-2 may infect the lower respiratory tract and cause alveolar damage as a result of dysfunctional immune responses. We discuss how this may lead to the induction of a 'leaky state' of both the epithelium and the endothelium, promoting inflammation and coagulation, while an influx of immune cells leads to overexuberant inflammatory responses and immunopathology. Finally, we highlight how these findings may aid the development of new therapeutic interventions against COVID-19.

Oridonin attenuates LPS-induced early pulmonary fibrosis by regulating impaired autophagy, oxidative stress, inflammation and EMT

CONTEXT

Oridonin (Ori) possesses anti-inflammatory, antioxidant and antitumor properties. However, the effects of Ori on Lipopolysaccharide (LPS)-induced early pulmonary fibrosis remain unclear.

OBJECTIVE

We evaluated the protective effects of Ori on the mice model of pulmonary fibrosis.

MATERIALS AND METHODS

The BALB/C mice were given LPS (1 mg/kg) or Ori (20 mg/kg) according to experimental grouping. Then the left lung tissues were used for HE, immunohistochemical and Masson staining, and the right lung tissues were used for hydroxyproline measurement and western blot experiments. Bronchoalveolar lavage fluid was collected for Giemsa staining.

RESULTS

The high levels of hydroxyproline induced by LPS were reduced by Ori treatment. Immunohistochemical staining and western blot analysis showed that Ori inhibited the increased levels of fibrosis-related proteins (α-smooth muscle actin, transforming growth factor-β, Collagen Ⅰ and phosphorylated-smad). Additionally, Ori treatment increased E-cadherin levels and decreased in Snail and Slug levels. Besides, Ori could suppress LPS-induced the infiltration of neutrophils and activation of the NLRP3 inflammasome. In addition, LPS caused the upregulation of NADPH oxidase 4 and exacerbated lung fibrosis. As the activator of NF-E2 related factor-2, Ori exerted protective effects in this animal model. Moreover, Ori reversed the LPS-triggered increases in Beclin-1, P62/sequestosome 1, autophagy related 3 and LC3.

CONCLUSIONS

These findings suggested that Ori protected against LPS-induced early pulmonary fibrosis by inhibiting NLRP3-dependent inflammation, NADPH oxidase 4-dependent oxidative stress, the impaired autophagy and epithelial mesenchymal transformation.

SARS-CoV-2 infection induces soluble platelet activation markers and PAI-1 in the early moderate stage of COVID-19

Introduction

Coagulation dysfunction and thromboembolism emerge as strong comorbidity factors in severe COVID‐19. However, it is unclear when particularly platelet activation markers and coagulation factors dysregulated during the pathogenesis of COVID‐19. Here, we sought to assess the levels of coagulation and platelet activation markers at moderate and severe stages of COVID‐19 to understand the pathogenesis.

Methods

To understand this, hospitalized COVID‐19 patients with (severe cases that required intensive care) or without pneumonia (moderate cases) were recruited. Phenotypic and molecular characterizations were performed employing basic coagulation tests including prothrombin time (PT), activated partial thromboplastin time (APTT), D‐Dimer, and tissue factor pathway inhibitor (TFPI). The flow cytometry‐based multiplex assays were performed to assess FXI, anti‐thrombin, prothrombin, fibrinogen, FXIII, P‐selectin, sCD40L, plasminogen, tissue plasminogen activator (tPA), plasminogen activator inhibitor‐1 (PAI‐1), and D‐Dimer.

Results

The investigations revealed induction of plasma P‐selectin and CD40 ligand (sCD40L) in moderate COVID‐19 cases, which were significantly abolished with the progression of COVID‐19 severity. Moreover, a profound reduction in plasma tissue factor pathway inhibitor (TFPI) and FXIII were identified particularly in the severe COVID‐19. Further analysis revealed fibrinogen induction in both moderate and severe patients. Interestingly, an elevated PAI‐1 more prominently in moderate, and tPA particularly in severe COVID‐19 cases were observed. Particularly, the levels of fibrinogen and tPA directly correlated with the severity of the disease.

Conclusions

In summary, induction of soluble P‐selectin, sCD40L, fibrinogen, and PAI‐1 suggests the activation of platelets and coagulation system at the moderate stage before COVID‐19 patients require intensive care. These findings would help in designing better thromboprophylaxis to limit the COVID‐19 severity.

Interstitial pneumonia and diffuse alveolar damage in domestic animals

Classification of pneumonia in animals has been controversial, and the most problematic pattern is interstitial pneumonia. This is true from the gross and histologic perspectives, and also from a mechanistic point of view. Multiple infectious and noninfectious diseases are associated with interstitial pneumonia, all of them converging in the release of inflammatory mediators that generate local damage and attract inflammatory cells that inevitably trigger a second wave of damage. Diffuse alveolar damage is one of the more frequently identified histologic types of interstitial pneumonia and involves injury to alveolar epithelial and/or endothelial cells, with 3 distinct stages. The first is the “exudative” stage, with alveolar edema and hyaline membranes. The second is the “proliferative” stage, with hyperplasia and reactive atypia of type II pneumocytes, infiltration of lymphocytes, plasma cells, and macrophages in the interstitium and early proliferation of fibroblasts. These stages are reversible and often nonfatal. If damage persists, there is a third “fibrosing” stage, characterized by fibrosis of the interstitium due to proliferation of fibroblasts/myofibroblasts, persistence of type II pneumocytes, segments of squamous metaplasia of alveolar epithelium, plus inflammation. Understanding the lesion patterns associated with interstitial pneumonias, their causes, and the underlying mechanisms aid in accurate diagnosis that involves an interdisciplinary collaborative approach involving pathologists, clinicians, and radiologists.

Combined Therapy with Ivermectin and Doxycycline can effectively alleviate the Cytokine Storm of COVID-19 Infection amid Vaccination Drive: A Narrative Review

An unprecedented global health crisis has developed due to the emergence of the mysterious coronavirus-2 of the severe acute respiratory syndrome, which has resulted in millions of deaths around the globe, as no therapy could control the ‘cytokine storm’. Consequently, many vaccines have been developed and several others are being developed for this infection. Although most of the approved vaccines have been highly effective, many developing, and economically poor countries are still deprived of vaccination against SARS-CoV-2 due to the unequal distribution of vaccines worldwide. Furthermore, the uncertainty about the effectiveness of the available vaccines against the emerging mutants and variants also remains a matter of concern. Due to the multistep pathogenesis and unique features, combination therapy using safe immunomodulatory and antiviral drugs should be considered as the most effective and acceptable therapeutic regimen for this infection. Based on a thorough assessment of the literature, it was determined that it would be interesting to study the therapeutic potential of ivermectin and doxycycline, given their roles in several biological pathways involved in SARS CoV-2 pathogenesis. Following that, a comprehensive literature search was undertaken using Scopus, Web of Science, and Pubmed, depending on the inclusion and exclusion criteria. The present study provides a mechanism and comprehensive report, highlighting the role of combined therapy with ivermectin and doxycycline in alleviating the ‘cytokine storm’ of COVID-19 infection.

Questions about COVID-19 associated coagulopathy: possible answers from the viscoelastic tests

Abnormal coagulation parameters are often observed in patients with coronavirus disease 2019 (COVID-19) and the severity of derangement has been associated with a poor prognosis. The COVID-19 associated coagulopathy (CAC) displays unique features that include a high risk of developing thromboembolic complications. Viscoelastic tests (VETs), such as thromboelastometry (ROTEM), thromboelastography (TEG) and Quantra Hemostasis Analyzer (Quantra), provide "dynamic" data on clot formation and dissolution; they are used in different critical care settings, both in hemorrhagic and in thrombotic conditions. In patients with severe COVID-19 infection VETs can supply to clinicians more information about the CAC, identifying the presence of hypercoagulable and hypofibrinolysis states. In the last year, many studies have proposed to explain the underlying characteristics of CAC; however, there remain many unanswered questions. We tried to address some of the important queries about CAC through VETs analysis.

Role of SARS-CoV-2 -induced cytokines and growth factors in coagulopathy and thromboembolism

Severe COVID-19 patients frequently present thrombotic complications which commonly lead to multiorgan failure and increase the risk of death. Severe SARS-CoV-2 infection induces the cytokine storm and is often associated with coagulation dysfunction. D-dimer, a hallmark of venous thromboembolism (VTE), is observed at a higher level in the majority of hospitalized COVID-19 patients. The precise molecular mechanism of the disproportionate effect of SARS-CoV-2 infection on the coagulation system is largely undefined. SARS-CoV-2 -induced endotheliopathy and, induction of cytokines and growth factors (GFs) most likely play important roles in platelet activation, coagulopathy, and VTE. Generally, viral infections lead to systemic inflammation and induction of numerous cytokines and GFs and many of them are reported to be associated with increased VTE. Most importantly, platelets play key thromboinflammatory roles linking coagulation to immune mediators in a variety of infections including response to viral infection. Since the pathomechanism of coagulopathy and VTE in COVID-19 is largely undefined, herein we highlight the association of dysregulated inflammatory cytokines and GFs with thrombotic complications and coagulopathy in COVID-19.

Side Effects and Efficacy of COVID-19 Vaccines among the Egyptian Population

BACKGROUND

Knowledge about a vaccine's side effects and efficacy is important to improving public vaccine acceptance. This study aimed to detect the safety and efficacy of vaccines among the Egyptian population.

METHODOLOGY AND RESULTS

Data was collected using an online survey from participants who took two doses of the BBIBP-CorV, ChAdOx1, or BNT162 vaccines. Pain at the vaccine injection site, muscle pain, fatigue, dizziness, fever, and headache were the most common side effects after the first and second doses. The number pf side effects was higher in ChAdOx1 than in BNT162 and BBIBP-CorV. Most of the side effects started on the first day after vaccination and persisted for 1-2 days. Vaccinated people with past coronavirus infections before vaccination developed better antibodies than those who were only vaccinated. The side-effect severity was greater after the first dose of BBIBP-CorV and ChAdOx1 than after the second dose, but in contrast, the side-effect severity was greater after the second dose of BNT162 vaccine than after the first dose. ChAdOx1 was more effective than BBIBP-CorV, and one dose of ChAdOx1 produced an immune response similar to that of two doses of BBIBP-CorV.

CONCLUSIONS

Coronavirus vaccines were well-tolerated, safe, and produced an immune response against the virus in most cases. Most postvaccine side effects were mild to moderate, which indicated the building of immunity by the body for protection.

Severity of respiratory failure and computed chest tomography in acute COVID-19 correlates with pulmonary function and respiratory symptoms after infection with SARS-CoV-2: An observational longitudinal study over 12 months

INTRODUCTION

Prospective and longitudinal data on pulmonary injury over one year after acute coronavirus disease 2019 (COVID-19) are sparse. We aim to determine reductions in pulmonary function and respiratory related quality of life up to 12 months after acute COVID-19.

METHODS

Patients with acute COVID-19 were enrolled into an ongoing single-centre, prospective observational study and prospectively examined 6 weeks, 3, 6 and 12 months after onset of COVID-19 symptoms. Chest CT-scans, pulmonary function and symptoms assessed by St. Georges Respiratory Questionnaire were used to evaluate respiratory limitations. Patients were stratified according to severity of acute COVID-19.

RESULTS

Median age of all patients was 57 years, 37.8% were female. Higher age, male sex and higher BMI were associated with acute-COVID-19 severity (p < 0.0001, 0.001 and 0.004 respectively). Also, pulmonary restriction and reduced carbon monoxide diffusion capacity was associated with disease severity. In patients with restriction and impaired diffusion capacity, FVC improved over 12 months from 61.32 to 71.82, TLC from 68.92 to 76.95, DLCO from 60.18 to 68.98 and KCO from 81.28 to 87.80 (percent predicted values; p = 0.002, 0.045, 0.0002 and 0.0005). The CT-score of lung involvement in the acute phase was associated with restriction and reduction in diffusion capacity in follow-up. Respiratory symptoms improved for patients in higher severity groups during follow-up, but not for patients with initially mild disease.

CONCLUSION

Severity of respiratory failure during COVID-19 correlates with the degree of pulmonary function impairment and respiratory quality of life in the year after acute infection.

SARS-CoV-2 Post Vaccinated Adverse Effects and Efficacy in the Egyptian Population

Vaccines are the solution to overcome SARS-CoV-2. This study aimed to determine the post-Sinopharm vaccine safety-profile and immunity through antibody titers. Data were collected using a structured questionnaire from Egyptian participants who received two doses of Sinopharm vaccine. Data were divided into three parts, the first and second parts were to detect participants’ post-first and second dose symptoms and practices, and the third for the results of IgG anti spike protein antibodies test and laboratory tests. Pain, redness, swelling at the injection site, headache, fatigue, and lethargy were the most common post-vaccine symptoms for both first and second doses. Most of the participants felt mild or no symptoms after vaccination. The symptoms started mostly during the first day post-vaccination and lasted for no more than two days. Forty-nine percent of the participants resulted in positive antibodies tests on day 18 post-vaccination. The average antibody level for vaccinated participants with past SARS-CoV-2 infection was much higher than that for non-past infected participants. These vaccines’ administration methods need to be reevaluated by changing the dose, dose interval, adding a third dose, or mixing it with other vaccines with different techniques to improve their protection rates. Further studies are required to validate this finding.

Virus infection induced pulmonary fibrosis

Pulmonary fibrosis is the end stage of a broad range of heterogeneous interstitial lung diseases and more than 200 factors contribute to it. In recent years, the relationship between virus infection and pulmonary fibrosis is getting more and more attention, especially after the outbreak of SARS-CoV-2 in 2019, however, the mechanisms underlying the virus-induced pulmonary fibrosis are not fully understood. Here, we review the relationship between pulmonary fibrosis and several viruses such as Human T-cell leukemia virus (HTLV), Human immunodeficiency virus (HIV), Cytomegalovirus (CMV), Epstein–Barr virus (EBV), Murine γ-herpesvirus 68 (MHV-68), Influenza virus, Avian influenza virus, Middle East Respiratory Syndrome (MERS)-CoV, Severe acute respiratory syndrome (SARS)-CoV and SARS-CoV-2 as well as the mechanisms underlying the virus infection induced pulmonary fibrosis. This may shed new light on the potential targets for anti-fibrotic therapy to treat pulmonary fibrosis induced by viruses including SARS-CoV-2.

COVID-19 and immunothrombosis: Pathophysiology and therapeutic implications

The coagulopathy of COVID-19 is characterised by significantly elevated D Dimer and fibrinogen, mild thrombocytopenia and a mildly prolonged PT/APTT. A high incidence of thrombotic complications occurs despite standard thromboprophylaxis. The evidence to date supports immunothrombosis as the underlying mechanism for this coagulopathy which is triggered by a hyperinflammatory response and endotheliopathy. A hypercoagulable state results from endothelial damage/activation, complement activation, platelet hyperactivity, release of Extracellular Neutrophil Traps, activation of the coagulation system and a "hypofibrinolytic" state. Significant cross-talk occurs between the innate/adaptive immune system, endothelium and the coagulation system. D dimer has been shown to be the most reliable predictor of disease severity, thrombosis, and overall survival. In this context, targeting pathways upstream of coagulation using novel or repurposed drugs alone or in combination with other anti-thrombotic agents may be a rational approach to prevent the mortality/morbidity due to COVID-19 associated coagulopathy.

A Composite study of Coagulation Milieu in Covid-19: Experience from a Tertiary Care Centre from India

BACKGROUND

The understanding of pathogenesis is necessary for the development of effective treatment for COVID-19. Various studies have postulated that there is a complex interplay of mediators of coagulation and inflammation responsible for the pathogenesis of COVID-19. We did this study on coagulation parameters and inflammatory markers and their effect on outcome in patients with COVID-19.

METHODS

This was a single centre observational cross-sectional study. Procoagulants [Prothrombin time (PT), activated partial thromboplastin time (APTT), D-dimer, lupus anticoagulant (LA), fibrinogen, factor-VIII (F-VIII)]; anticoagulants [protein-C (PC), protein-S (PS), antithrombin] and inflammatory markers [interleukin-6 (IL-6) and highly sensitive - C-reactive protein (hs-CRP)] were measured at the time of hospitalization and correlated with the severity of the disease.

RESULTS

A total of 230 patients were enrolled, of which 61.3%, 20.0%, and 18.7% had asymptomatic/ mild, moderate, or severe disease, respectively. COVID-19 disease severity was associated with rising trends with coagulation parameters (PT, APTT, D-Dimer; p value 0.01, <0.0001, <0.0001, respectively). Falling trends of anticoagulant (PC, Antithrombin; p value <0.0001, 0.003 respectively) and rising trends of procoagulant (fibrinogen, F-VIII; p value 0.004, <0.0001 respectively) were observed with increasing COVID-19 disease severity. Multivariate logistic regression analysis found that advanced age, D-Dimer, and hs-CRP (p value 0.035, 0.018, <0.0001 respectively) were independent predictors of mortality in COVID-19. Procoagulant parameters (D-dimer, APTT, Factor VIII) were positively correlated with anticoagulant parameters (PC and PS) and inflammatory parameters (hs-CRP).

CONCLUSIONS

This study revealed increased levels of coagulation and inflammatory parameters, which correlated with the severity of COVID-19. Age, D-dimer, IL-6, hs-CRP, APTT, fibrinogen, and Factor VIII were significantly higher in patients with moderate and severe disease as compared to asymptomatic/mild disease. Advanced age, D dimer, and hs-CRP were significantly associated with poor outcomes.

SARS-CoV-2 Exacerbates COVID-19 Pathology Through Activation of the Complement and Kinin Systems

Infection with SARS-CoV-2 triggers the simultaneous activation of innate inflammatory pathways including the complement system and the kallikrein-kinin system (KKS) generating in the process potent vasoactive peptides that contribute to severe acute respiratory syndrome (SARS) and multi-organ failure. The genome of SARS-CoV-2 encodes four major structural proteins - the spike (S) protein, nucleocapsid (N) protein, membrane (M) protein, and the envelope (E) protein. However, the role of these proteins in either binding to or activation of the complement system and/or the KKS is still incompletely understood. In these studies, we used: solid phase ELISA, hemolytic assay and surface plasmon resonance (SPR) techniques to examine if recombinant proteins corresponding to S1, N, M and E: (a) bind to C1q, gC1qR, FXII and high molecular weight kininogen (HK), and (b) activate complement and/or the KKS. Our data show that the viral proteins: (a) bind C1q and activate the classical pathway of complement, (b) bind FXII and HK, and activate the KKS in normal human plasma to generate bradykinin and (c) bind to gC1qR, the receptor for the globular heads of C1q (gC1q) which in turn could serve as a platform for the activation of both the complement system and KKS. Collectively, our data indicate that the SARS-CoV-2 viral particle can independently activate major innate inflammatory pathways for maximal damage and efficiency. Therefore, if efficient therapeutic modalities for the treatment of COVID-19 are to be designed, a strategy that includes blockade of the four major structural proteins may provide the best option.

Sinoacutine inhibits inflammatory responses to attenuates acute lung injury by regulating NF-κB and JNK signaling pathways

Background

Stephania yunnanensis H. S. Lo is widely used as an antipyretic, analgesic and anti-inflammatory herbal medicine in SouthWest China. In this study, we investigated the anti-inflammatory activity and mechanism of sinoacutine (sino), one of the primary components extracted from this plant.

Methods

A RAW264.7 cell model was established using lipopolysaccharide (LPS) induced for estimation of cytokines in vitro, qPCR was used to estimate gene expression, western blot analysis was used to estimate protein level and investigate the regulation of NF- κB, JNK and MAPK signal pathway. In addition, an acute lung injury model was established to determine lung index and levels of influencing factors.

Results

Using the RAW264.7 model, we found that sino reduced levels of nitric oxide (NO), tumour necrosis factor-α (TNF-α), interleukin (IL)-1β and prostaglandin E₂ (PGE₂) but increased levels of IL-6. qPCR analysis revealed that sino (50, 25 μg/ml) inhibited gene expression of nitric oxide synthase (iNOS). western blot analysis showed that sino significantly inhibited protein levels of both iNOS and COX-2. Further signalling pathway analysis validated that sino also inhibited phosphorylation of p65 in the NF-κB and c-Jun NH2 terminal kinase (JNK) signalling pathways but promoted the phosphorylation of extracellular signal regulated kinase (ERK) and p38 in the MAPK signalling pathway. In addition, in a mouse model induced by LPS, we determined that sino reduced the lung index and the levels of myeloperoxidase (MPO), NO, IL-6 and TNF-α in lung tissues and bronchoalveolar lavage fluid (BALF) in acute lung injury (ALI).

Conclusion

Taken together, our results demonstrate that sino is a promising drug to alleviate LPS-induced inflammatory reactions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03458-0.

Tissue factor expression, extracellular vesicles, and thrombosis after infection with the respiratory viruses influenza A virus and coronavirus

Tissue factor (TF) is induced in a variety of cell types during viral infection, which likely contributes to disseminated intravascular coagulation and thrombosis. TF-expressing cells also release TF-positive extracellular vesicles (EVs) into the circulation that can be measured using an EVTF activity assay. This review summarizes studies that analyze TF expression, TF-positive EVs, activation of coagulation, and thrombosis after infection with influenza A virus (IAV) and coronaviruses (CoVs), including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), SARS-CoV, and Middle East respiratory syndrome CoV (MERS-CoV). The current pandemic of coronavirus disease 2019 (COVID-19) is caused by infection with SARS-CoV-2. Infection of mice with IAV increased TF expression in lung epithelial cells as well as increased EVTF activity and activation of coagulation in the bronchoalveolar lavage fluid (BALF). Infection of mice with MERS-CoV, SARS-CoV, and SARS-CoV-2 also increased lung TF expression. Single-cell RNA sequencing analysis on the BALF from severe COVID-19 patients revealed increased TF mRNA expression in epithelial cells. TF expression was observed in peripheral blood mononuclear cells infected with SARS-CoV. TF was also expressed by peripheral blood mononuclear cells, monocytes in platelet-monocyte aggregates, and neutrophils isolated from COVID-19 patients. Elevated circulating EVTF activity was observed in severe IAV and COVID-19 patients. Importantly, EVTF activity was associated with mortality in severe IAV patients and with plasma D-dimer, severity, thrombosis, and mortality in COVID-19 patients. These studies strongly suggest that increased TF expression in patients infected with IAV and pathogenic CoVs contributes to thrombosis.

Mouse-adapted SARS-CoV-2 protects animals from lethal SARS-CoV challenge

The emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has resulted in a pandemic causing significant damage to public health and the economy. Efforts to understand the mechanisms of Coronavirus Disease 2019 (COVID-19) have been hampered by the lack of robust mouse models. To overcome this barrier, we used a reverse genetic system to generate a mouse-adapted strain of SARS-CoV-2. Incorporating key mutations found in SARS-CoV-2 variants, this model recapitulates critical elements of human infection including viral replication in the lung, immune cell infiltration, and significant in vivo disease. Importantly, mouse adaptation of SARS-CoV-2 does not impair replication in human airway cells and maintains antigenicity similar to human SARS-CoV-2 strains. Coupled with the incorporation of mutations found in variants of concern, CMA3p20 offers several advantages over other mouse-adapted SARS-CoV-2 strains. Using this model, we demonstrate that SARS-CoV-2-infected mice are protected from lethal challenge with the original Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), suggesting immunity from heterologous Coronavirus (CoV) strains. Together, the results highlight the use of this mouse model for further study of SARS-CoV-2 infection and disease.

A stent for branch pulmonary artery stenosis after double-lung transplantation in a patient with COVID-19: a case report

Background

Coronavirus disease 2019 (COVID-19) continues to be a pandemic worldwide. Lung transplantation is the last option to increase life expectancy of end-stage COVID-19 patients. Branch pulmonary artery stenosis (PAS) is a rare complication after lung transplantation with an extremely poor prognosis. The current trend in the management of branch PAS is percutaneous balloon angioplasty and/or stent implantation, rather than high-risk reoperation with a lower success rate.

Case summary

The subject was a 54-year-old male with severe acute respiratory syndrome coronavirus 2 infection who underwent a double-lung transplantation. He suffered hypoxaemia and right heart dysfunction following the operation. Right cardiac catheterization and pulmonary angiography examination revealed severe stenosis of the right branch pulmonary artery. Due to immunosuppression and reduced coagulation function, the patient underwent pulmonary artery balloon dilatation and stent implantation, and ultimately recovered well.

Discussion

The combination of balloon dilatation and stent implantation is a good alternative to reoperation for patients with COVID-19.

Update on endothelial dysfunction in COVID-19: severe disease, long COVID-19 and pediatric characteristics

Objectives

To review current literature on the role of endothelial dysfunction in coronavirus disease-2019 (COVID-19) infection in terms of pathophysiology, laboratory features and markers, clinical phenotype in adults and children, as well as long COVID-19.

Content

We conducted a thorough assessment of the literature and critically analyzed current data, mostly utilizing the PubMed and Medline search engines to find original studies published in the previous decade.

Summary and Outlook

Accumulating evidence suggests that endothelial dysfunction may be a common denominator of severe COVID-19 in adults and children, as well as long COVID-19, implicating mutual pathophysiological pathways. This narrative review summarizes the up-to-date knowledge of endothelial dysfunction caused by COVID-19, including novel aspects of long COVID-19 and pediatric disease. This knowledge is important in order not only to understand the multisystemic attack of COVID-19, but also to improve patient management and prognosis.

Systemic inflammation in COVID‐19 patients may induce various types of venous and arterial thrombosis: A systematic review

COVID‐19 is a global pandemic with a daily increasing number of affected individuals. Thrombosis is a severe complication of COVID‐19 that leads to a worse clinical course with higher rates of mortality. Multiple lines of evidence suggest that hyperinflammation plays a crucial role in disease progression. This review compiles clinical data of COVID‐19 patients who developed thrombotic complications to investigate the possible role of hyperinflammation in inducing hypercoagulation. A systematic literature search was performed using PubMed, Embase, Medline and Scopus to identify relevant clinical studies that investigated thrombotic manifestations and reported inflammatory and coagulation biomarkers in COVID‐19 patients. Only 54 studies met our inclusion criteria, the majority of which demonstrated significantly elevated inflammatory markers. In the cohort studies with control, D‐dimer was significantly higher in COVID‐19 patients with thrombosis as compared to the control. Pulmonary embolism, deep vein thrombosis and strokes were frequently reported which could be attributed to the hyperinflammatory response associated with COVID‐19 and/or to the direct viral activation of platelets and endothelial cells, two mechanisms that are discussed in this review. It is recommended that all admitted COVID‐19 patients should be assessed for hypercoagulation. Furthermore, several studies have suggested that anticoagulation may be beneficial, especially in hospitalized non‐ICU patients. Although vaccines against SARS‐CoV‐2 have been approved and distributed in several countries, research should continue in the field of prevention and treatment of COVID‐19 and its severe complications including thrombosis due to the emergence of new variants against which the efficacy of the vaccines is not yet clear.

Revealed pathophysiological mechanisms of crosslinking interaction of affected vital organs in COVID-19

SARS-CoV-2 is one of the main serious challenges of human societies, which emerged in December 2019 from China and quickly extends to all parts of the world. The virus was previously believed to only affect the lungs and respiratory system, but subsequent research has revealed that it affects a variety of organs. For this reason, this disease is known as a multiorgan disease. Current article aimed to highlight latest information and updates about molecular studies regarding pathogenesis of SARS-CoV-2 in kidney, liver, and cardiovascular and respiratory systems, as well as the mechanisms of interaction of these organs with each other to cause clinical manifestations in patients.

Utility of various inflammatory markers in predicting outcomes of hospitalized patients with COVID-19 pneumonia: A single-center experience

AIM

The aim of the study is to study the utility of various inflammatory markers in predicting outcomes of hospitalized patients with coronavirus disease 2019 (COVID-19) pneumonia.

PRIMARY OBJECTIVE

The primary objective of the study is to analyze the correlation between various inflammatory markers and in-hospital mortality.

SECONDARY OBJECTIVES

The secondary objective of the study is to assess the correlation between the inflammatory markers and clinical category of patients, and other outcomes such as length of hospital stay and need for invasive ventilation.

METHODS

A retrospective cross-sectional observational study was done in 221 hospitalized patients who were diagnosed with COVID-19 pneumonia in a tertiary care hospital in South India from May 2020 to July 2020. Clinical and laboratory data of patients diagnosed with COVID-19 pneumonia were collected. This included epidemiological data, clinical data, laboratory parameter (neutrophil: lymphocyte [N: L] ratio, C-reactive protein [CRP], ferritin, interleukin-6 [IL-6], lactate dehydrogenase, D-dimer, and procalcitonin), treatment details, and outcomes.

RESULTS

IL-6 levels >60.5 pg/mL and D-dimer levels >0.5 mcg/mL predicted in-hospital mortality with sensitivities of 80% and 76.7%, respectively. N: L ratio and CRP levels had good correlation with the need for oxygen supplementation and/or invasive ventilation.

CONCLUSIONS

Judicious use of COVID-19 biomarkers could help in disease prognostication and thereby provide guidance to devise appropriate management strategies.

Coronavirus disease 2019 (COVID-19): Multisystem review of pathophysiology

Coronavirus disease-19 (COVID-19) pandemic is associated with high morbidity and mortality. COVID-19, which is caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2), affects multiple organ systems through a myriad of mechanisms. Afflicted patients present with a vast constellation of symptoms, from asymptomatic disease to life-threatening complications. The most common manifestations pertain to mild pulmonary symptoms, which can progress to respiratory distress syndrome and venous thromboembolism. However, in patients with renal failure, life-threatening cardiac abnormalities can ensue. Various mechanisms such as viral entry through Angiotensin receptor (ACE) affecting multiple organs and thus releasing pro-inflammatory markers have been postulated. Nevertheless, the predictors of various presentations in the affected population remain elusive. An ameliorated understanding of the pathology and pathogenesis of the viral infection has led to the development of variable treatment options, with many more that are presently under trial. This review article discusses the pathogenesis of multiple organ involvement secondary to COVID-19 infection in infected patients.

•

This review sheds light on the pathogenesis of multi-organ involvement secondary to COVID-19 infection.

•

The predictors of various presentations in the affected population are not clear at present. A better understanding of the pathology and pathogenesis of the viral infection will be pivotal in the development of variable treatment options.

•

Various proposed mechanisms such as viral entry through Angiotensin receptor (ACE) affecting multiple organs, releasing pro-inflammatory markers and cytokines inducing hypercoagulable state and cytokine storm syndrome have been postulated.

COVID-19-related laboratory coagulation findings

The alterations in the hemostatic balance in COVID-19 patients are strongly disturbed and contribute to a high prothrombotic status. The high rate of venous thromboembolism in COVID-19 patients goes along with derangements in coagulation laboratory parameters. Hemostasis testing has an important role in diagnosed COVID-19 patients. Elevated D-dimer levels were found to be a crucial laboratory marker in the risk assessment of thrombosis in COVID-19 patients. The diagnostic approach also includes prothrombin time and platelet count. Fibrinogen might give an indication for worsening coagulopathy. Other markers (activated partial thromboplastin time (aPTT), fibrinolysis parameters, coagulation factors, natural anticoagulants, antiphospholipid antibodies and parameters obtained by thromboelastography or thrombin generation assays) have been described as being deranged. These may help to understand the pathophysiology of thrombosis in COVID-19 patients but have currently no place in diagnosis or management in COVID-19 patients. For monitoring the heparin anticoagulant therapy, the anti-Xa assay is suggested, because the severe acute-phase reaction (high fibrinogen and high factor VIII) shortens the aPTT.

Gene Expression Meta-Analysis Reveals Interferon-Induced Genes Associated With SARS Infection in Lungs

Background

Severe Acute Respiratory Syndrome (SARS) corona virus (CoV) infections are a serious public health threat because of their pandemic-causing potential. This work is the first to analyze mRNA expression data from SARS infections through meta-analysis of gene signatures, possibly identifying therapeutic targets associated with major SARS infections.

Methods

This work defines 37 gene signatures representing SARS-CoV, Middle East Respiratory Syndrome (MERS)-CoV, and SARS-CoV2 infections in human lung cultures and/or mouse lung cultures or samples and compares them through Gene Set Enrichment Analysis (GSEA). To do this, positive and negative infectious clone SARS (icSARS) gene panels are defined from GSEA-identified leading-edge genes between two icSARS-CoV derived signatures, both from human cultures. GSEA then is used to assess enrichment and identify leading-edge icSARS panel genes between icSARS gene panels and 27 other SARS-CoV gene signatures. The meta-analysis is expanded to include five MERS-CoV and three SARS-CoV2 gene signatures. Genes associated with SARS infection are predicted by examining the intersecting membership of GSEA-identified leading-edges across gene signatures.

Results

Significant enrichment (GSEA p<0.001) is observed between two icSARS-CoV derived signatures, and those leading-edge genes defined the positive (233 genes) and negative (114 genes) icSARS panels. Non-random significant enrichment (null distribution p<0.001) is observed between icSARS panels and all verification icSARSvsmock signatures derived from human cultures, from which 51 over- and 22 under-expressed genes are shared across leading-edges with 10 over-expressed genes already associated with icSARS infection. For the icSARSvsmock mouse signature, significant, non-random significant enrichment held for only the positive icSARS panel, from which nine genes are shared with icSARS infection in human cultures. Considering other SARS strains, significant, non-random enrichment (p<0.05) is observed across signatures derived from other SARS strains for the positive icSARS panel. Five positive icSARS panel genes, CXCL10, OAS3, OASL, IFIT3, and XAF1, are found across mice and human signatures regardless of SARS strains.

Conclusion

The GSEA-based meta-analysis approach used here identifies genes with and without reported associations with SARS-CoV infections, highlighting this approach’s predictability and usefulness in identifying genes that have potential as therapeutic targets to preclude or overcome SARS infections.

Elevated Expression Levels of Lung Complement Anaphylatoxin, Neutrophil Chemoattractant Chemokine IL-8, and RANTES in MERS-CoV-Infected Patients: Predictive Biomarkers for Disease Severity and Mortality

The complement system, a network of highly-regulated proteins, represents a vital part of the innate immune response. Over-activation of the complement system plays an important role in inflammation, tissue damage, and infectious disease severity. The prevalence of MERS-CoV in Saudi Arabia remains significant and cases are still being reported. The role of complement in Middle East Respiratory Syndrome coronavirus (MERS-CoV) pathogenesis and complement-modulating treatment strategies has received limited attention, and studies involving MERS-CoV-infected patients have not been reported. This study offers the first insight into the pulmonary expression profile including seven complement proteins, complement regulatory factors, IL-8, and RANTES in MERS-CoV infected patients without underlying chronic medical conditions. Our results significantly indicate high expression levels of complement anaphylatoxins (C3a and C5a), IL-8, and RANTES in the lungs of MERS-CoV-infected patients. The upregulation of lung complement anaphylatoxins, C5a, and C3a was positively correlated with IL-8, RANTES, and the fatality rate. Our results also showed upregulation of the positive regulatory complement factor P, suggesting positive regulation of the complement during MERS-CoV infection. High levels of lung C5a, C3a, factor P, IL-8, and RANTES may contribute to the immunopathology, disease severity, ARDS development, and a higher fatality rate in MERS-CoV-infected patients. These findings highlight the potential prognostic utility of C5a, C3a, IL-8, and RANTES as biomarkers for MERS-CoV disease severity and mortality. To further explore the prediction of functional partners (proteins) of highly expressed proteins (C5a, C3a, factor P, IL-8, and RANTES), the computational protein–protein interaction (PPI) network was constructed, and six proteins (hub nodes) were identified.