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1.
Int J Mol Sci ; 22(24)2021 Dec 20.
Article in English | MEDLINE | ID: covidwho-1580687

ABSTRACT

COVID-19 infection is associated with a broad spectrum of presentations, but alveolar capillary microthrombi have been described as a common finding in COVID-19 patients, appearing as a consequence of a severe endothelial injury with endothelial cell membrane disruption. These observations clearly point to the identification of a COVID-19-associated coagulopathy, which may contribute to thrombosis, multi-organ damage, and cause of severity and fatality. One significant finding that emerges in prothrombotic abnormalities observed in COVID-19 patients is that the coagulation alterations are mainly mediated by the activation of platelets and intrinsically related to viral-mediated endothelial inflammation. Beyond the well-known role in hemostasis, the ability of platelets to also release various potent cytokines and chemokines has elevated these small cells from simple cell fragments to crucial modulators in the blood, including their inflammatory functions, that have a large influence on the immune response during infectious disease. Indeed, platelets are involved in the pathogenesis of acute lung injury also by promoting NET formation and affecting vascular permeability. Specifically, the deposition by activated platelets of the chemokine platelet factor 4 at sites of inflammation promotes adhesion of neutrophils on endothelial cells and thrombogenesis, and it seems deeply involved in the phenomenon of vaccine-induced thrombocytopenia and thrombosis. Importantly, the hyperactivated platelet phenotype along with evidence of cytokine storm, high levels of P-selectin, D-dimer, and, on the other hand, decreased levels of fibrinogen, von Willebrand factor, and thrombocytopenia may be considered suitable biomarkers that distinguish the late stage of COVID-19 progression in critically ill patients.


Subject(s)
Blood Platelets/physiology , COVID-19/blood , Thrombosis/pathology , Blood Coagulation , Blood Coagulation Disorders/etiology , Blood Platelets/metabolism , Blood Platelets/virology , COVID-19/metabolism , Cytokine Release Syndrome , Endothelial Cells/pathology , Fibrin Fibrinogen Degradation Products , Hemostasis , Humans , Inflammation , Phenotype , Platelet Activation/physiology , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Thrombocytopenia/metabolism , Thrombosis/metabolism , Thrombosis/virology
2.
BMC Genom Data ; 22(1): 49, 2021 11 14.
Article in English | MEDLINE | ID: covidwho-1518254

ABSTRACT

BACKGROUND: There is an urgent need to understand the key events driving pathogenesis of severe COVID-19 disease, so that precise treatment can be instituted. In this respect NETosis is gaining increased attention in the scientific community, as an important pathological process contributing to mortality. We sought to test if indeed there exists robust evidence of NETosis in multiple transcriptomic data sets from human subjects with severe COVID-19 disease. Gene set enrichment analysis was performed to test for up-regulation of gene set functional in NETosis in the blood of patients with COVID-19 illness. RESULTS: Blood gene expression functional in NETosis increased with severity of illness, showed negative correlation with blood oxygen saturation, and was validated in the lung of COVID-19 non-survivors. Temporal expression of IL-6 was compared between severe and moderate illness with COVID-19. Unsupervised clustering was performed to reveal co-expression of IL-6 with complement genes. In severe COVID-19 illness, there is transcriptional evidence of activation of NETosis, complement and coagulation cascade, and negative correlation between NETosis and respiratory function (oxygen saturation). An early spike in IL-6 is observed in severe COVID-19 illness that is correlated with complement activation. CONCLUSIONS: Based on the transcriptional dynamics of IL-6 expression and its downstream effect on complement activation, we constructed a model that links early spike in IL-6 level with persistent and self-perpetuating complement activation, NETosis, immunothrombosis and respiratory dysfunction. Our model supports the early initiation of anti-IL6 therapy in severe COVID-19 disease before the life-threatening complications of the disease can perpetuate themselves autonomously.


Subject(s)
COVID-19/immunology , Extracellular Traps , Interleukin-6 , Thrombosis/virology , Transcriptome , COVID-19/pathology , Complement System Proteins/genetics , Humans , Interleukin-6/genetics , Oxygen
3.
Blood ; 138(16): 1481-1489, 2021 10 21.
Article in English | MEDLINE | ID: covidwho-1484294

ABSTRACT

A subset of patients with coronavirus disease 2019 (COVID-19) become critically ill, suffering from severe respiratory problems and also increased rates of thrombosis. The causes of thrombosis in severely ill patients with COVID-19 are still emerging, but the coincidence of critical illness with the timing of the onset of adaptive immunity could implicate an excessive immune response. We hypothesized that platelets might be susceptible to activation by anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) antibodies and might contribute to thrombosis. We found that immune complexes containing recombinant SARS-CoV-2 spike protein and anti-spike immunoglobulin G enhanced platelet-mediated thrombosis on von Willebrand factor in vitro, but only when the glycosylation state of the Fc domain was modified to correspond with the aberrant glycosylation previously identified in patients with severe COVID-19. Furthermore, we found that activation was dependent on FcγRIIA, and we provide in vitro evidence that this pathogenic platelet activation can be counteracted by the therapeutic small molecules R406 (fostamatinib) and ibrutinib, which inhibit tyrosine kinases Syk and Btk, respectively, or by the P2Y12 antagonist cangrelor.


Subject(s)
Blood Platelets/pathology , COVID-19/complications , Immunoglobulin G/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/metabolism , Thrombosis/pathology , von Willebrand Factor/metabolism , Antibodies, Viral/blood , Antibodies, Viral/immunology , Antigen-Antibody Complex/immunology , Blood Platelets/immunology , Blood Platelets/metabolism , COVID-19/immunology , COVID-19/virology , Glycosylation , Humans , Platelet Activation/immunology , Thrombosis/immunology , Thrombosis/virology , von Willebrand Factor/genetics
4.
Clin Appl Thromb Hemost ; 27: 10760296211042940, 2021.
Article in English | MEDLINE | ID: covidwho-1484251

ABSTRACT

The world is in a hard battle against COVID-19. Endothelial cells are among the most critical targets of SARS-CoV-2. Dysfunction of endothelium leads to vascular injury following by coagulopathies and thrombotic conditions in the vital organs increasing the risk of life-threatening events. Growing evidences revealed that endothelial dysfunction and consequent thrombotic conditions are associated with the severity of outcomes. It is not yet fully clear that these devastating sequels originate directly from the virus or a side effect of virus-induced cytokine storm. Due to endothelial dysfunction, plasma levels of some biomarkers are changed and relevant clinical manifestations appear as well. Stabilization of endothelial integrity and supporting its function are among the promising therapeutic strategies. Other than respiratory, COVID-19 could be called a systemic vascular disease and this aspect should be scrutinized in more detail in order to reduce related mortality. In the present investigation, the effects of COVID-19 on endothelial function and thrombosis formation are discussed. In this regard, critical players, laboratory findings, clinical manifestation, and suggestive therapies are presented.


Subject(s)
Blood Coagulation , COVID-19/virology , Endothelial Cells/virology , Endothelium, Vascular/virology , SARS-CoV-2/pathogenicity , Thrombosis/virology , Animals , COVID-19/blood , COVID-19/pathology , COVID-19/physiopathology , Endothelial Cells/metabolism , Endothelial Cells/pathology , Endothelium, Vascular/metabolism , Endothelium, Vascular/physiopathology , Host-Pathogen Interactions , Humans , Signal Transduction , Thrombosis/blood , Thrombosis/pathology , Thrombosis/physiopathology
5.
Int J Biol Macromol ; 192: 1040-1057, 2021 Dec 01.
Article in English | MEDLINE | ID: covidwho-1466382

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent responsible for the Coronavirus Disease-2019 (COVID-19) pandemic, has infected over 185 million individuals across 200 countries since December 2019 resulting in 4.0 million deaths. While COVID-19 is primarily associated with respiratory illnesses, an increasing number of clinical reports indicate that severely ill patients often develop thrombotic complications that are associated with increased mortality. As a consequence, treatment strategies that target COVID-associated thrombosis are of utmost clinical importance. An array of pharmacologically active compounds from natural products exhibit effects on blood coagulation pathways, and have generated interest for their potential therapeutic applications towards thrombotic diseases. In particular, a number of snake venom compounds exhibit high specificity on different blood coagulation factors and represent excellent tools that could be utilized to treat thrombosis. The aim of this review is to provide a brief summary of the current understanding of COVID-19 associated thrombosis, and highlight several snake venom compounds that could be utilized as antithrombotic agents to target this disease.


Subject(s)
COVID-19/blood , Fibrinolytic Agents/pharmacology , Snake Venoms/pharmacology , Thrombosis/drug therapy , Thrombosis/virology , Anticoagulants/therapeutic use , Blood Coagulation/drug effects , COVID-19/drug therapy , COVID-19/epidemiology , COVID-19/pathology , Humans , Pandemics , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicity
7.
Br J Community Nurs ; 26(10): 474-480, 2021 Oct 02.
Article in English | MEDLINE | ID: covidwho-1464047

ABSTRACT

Despite its many devastating effects, the COVID-19 pandemic has had a positive impact in the ways in which society, scientific institutions, governing bodies, businesses, educational organisations, and communication have functioned unchallenged over the years. Rapid advancement in science enabled identification and characterisation of the virus and in developing vaccines to combat the disease. The mysterious ways in which the virus attacks the vital organs that lead on to multiorgan failure and thrombosis of the arterial and venous system have also been revealed. The ability to study the microcirculatory changes at the bedside and predict prognosis is a way forward. All the evidence suggests that the outcome of COVID-19 infection is related to the severity of the disease seen in the intensive care unit setting. This article discusses microcirculatory changes and immune coagulopathy caused by COVID-19.


Subject(s)
COVID-19 , Microcirculation , Thrombosis , COVID-19/complications , COVID-19/nursing , Humans , Thrombosis/virology
8.
J Clin Invest ; 130(11): 6151-6157, 2020 11 02.
Article in English | MEDLINE | ID: covidwho-1435146

ABSTRACT

Emerging data indicate that complement and neutrophils contribute to the maladaptive immune response that fuels hyperinflammation and thrombotic microangiopathy, thereby increasing coronavirus 2019 (COVID-19) mortality. Here, we investigated how complement interacts with the platelet/neutrophil extracellular traps (NETs)/thrombin axis, using COVID-19 specimens, cell-based inhibition studies, and NET/human aortic endothelial cell (HAEC) cocultures. Increased plasma levels of NETs, tissue factor (TF) activity, and sC5b-9 were detected in patients. Neutrophils of patients yielded high TF expression and released NETs carrying active TF. Treatment of control neutrophils with COVID-19 platelet-rich plasma generated TF-bearing NETs that induced thrombotic activity of HAECs. Thrombin or NETosis inhibition or C5aR1 blockade attenuated platelet-mediated NET-driven thrombogenicity. COVID-19 serum induced complement activation in vitro, consistent with high complement activity in clinical samples. Complement C3 inhibition with compstatin Cp40 disrupted TF expression in neutrophils. In conclusion, we provide a mechanistic basis for a pivotal role of complement and NETs in COVID-19 immunothrombosis. This study supports strategies against severe acute respiratory syndrome coronavirus 2 that exploit complement or NETosis inhibition.


Subject(s)
Betacoronavirus , Complement Membrane Attack Complex , Coronavirus Infections , Extracellular Traps , Neutrophils , Pandemics , Pneumonia, Viral , Thromboplastin , Thrombosis , Aged , Betacoronavirus/immunology , Betacoronavirus/metabolism , COVID-19 , Complement Activation/drug effects , Complement Membrane Attack Complex/immunology , Complement Membrane Attack Complex/metabolism , Coronavirus Infections/blood , Coronavirus Infections/immunology , Extracellular Traps/immunology , Extracellular Traps/metabolism , Female , Humans , Male , Middle Aged , Neutrophils/immunology , Neutrophils/metabolism , Peptides, Cyclic/pharmacology , Pneumonia, Viral/blood , Pneumonia, Viral/immunology , Receptor, Anaphylatoxin C5a/antagonists & inhibitors , Receptor, Anaphylatoxin C5a/blood , Receptor, Anaphylatoxin C5a/immunology , Respiratory Distress Syndrome/blood , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/virology , SARS-CoV-2 , Thrombin/immunology , Thrombin/metabolism , Thromboplastin/immunology , Thromboplastin/metabolism , Thrombosis/blood , Thrombosis/immunology , Thrombosis/virology
9.
J Thromb Thrombolysis ; 52(3): 708-714, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1406170

ABSTRACT

Coronavirus disease 2019 (Covid-19) is associated with a high incidence of venous and arterial thromboembolic events. Currently, there are no clinical or laboratory markers that predict thrombotic risk. Circulating immature platelets are hyper-reactive platelets, which are associated with arterial thrombotic events. The aim of this study was to assess whether the proportion of circulating immature platelets is associated with disease severity in Covid-19 patients. Patients admitted with Covid-19 disease were prospectively assessed. Immature platelet count (IPC) and immature platelet fraction (IPF) were measured at admission and at additional time points during the hospital course using the Sysmex XN-3000 auto-analyzer. A total of 136 consecutive patients with Covid-19 were recruited [mean age 60 ± 19 years, 49% woman, 56 (41%) had mild-moderate disease and 80 (59%) had severe disease at presentation]. The median IPF% was higher in patients with severe compared to mild-moderate disease [5.8 (3.9-8.7) vs. 4.2 (2.73-6.45), respectively, p = 0.01]. The maximal IPC value was also higher in patients with severe disease [15 (10.03-21.56), vs 10.9 (IQR 6.79-15.62), respectively, p = 0.001]. Increased IPC was associated with increased length of hospital stay. Patients with severe Covid-19 have higher levels of IPF than patients with mild-moderate disease. IPF may serve as a prognostic marker for disease severity in Covid-19 patients.


Subject(s)
Blood Platelets/virology , COVID-19/virology , SARS-CoV-2/pathogenicity , Thrombosis/virology , Adult , Aged , COVID-19/blood , COVID-19/diagnosis , COVID-19/therapy , Female , Hospital Mortality , Host-Pathogen Interactions , Humans , Length of Stay , Male , Middle Aged , Patient Admission , Platelet Count , Predictive Value of Tests , Prognosis , Prospective Studies , Risk Factors , Severity of Illness Index , Thrombosis/blood , Thrombosis/diagnosis , Time Factors
10.
PLoS One ; 16(9): e0256988, 2021.
Article in English | MEDLINE | ID: covidwho-1394552

ABSTRACT

Epidemiological studies suggest that individuals with comorbid conditions including diabetes, chronic lung, inflammatory and vascular disease, are at higher risk of adverse COVID-19 outcomes. Genome-wide association studies have identified several loci associated with increased susceptibility and severity for COVID-19. However, it is not clear whether these associations are genetically determined or not. We used a Phenome-Wide Association (PheWAS) approach to investigate the role of genetically determined COVID-19 susceptibility on disease related outcomes. PheWAS analyses were performed in order to identify traits and diseases related to COVID-19 susceptibility and severity, evaluated through a predictive COVID-19 risk score. We utilised phenotypic data in up to 400,000 individuals from the UK Biobank, including Hospital Episode Statistics and General Practice data. We identified a spectrum of associations between both genetically determined COVID-19 susceptibility and severity with a number of traits. COVID-19 risk was associated with increased risk for phlebitis and thrombophlebitis (OR = 1.11, p = 5.36e-08). We also identified significant signals between COVID-19 susceptibility with blood clots in the leg (OR = 1.1, p = 1.66e-16) and with increased risk for blood clots in the lung (OR = 1.12, p = 1.45 e-10). Our study identifies significant association of genetically determined COVID-19 with increased blood clot events in leg and lungs. The reported associations between both COVID-19 susceptibility and severity and other diseases adds to the identification and stratification of individuals at increased risk, adverse outcomes and long-term effects.


Subject(s)
COVID-19/genetics , Obesity/genetics , Thrombophlebitis/genetics , Thrombosis/genetics , COVID-19/epidemiology , COVID-19/virology , Cardiovascular Diseases/genetics , Cardiovascular Diseases/pathology , Cardiovascular Diseases/virology , Female , Genetic Predisposition to Disease , Humans , Male , Mendelian Randomization Analysis , Obesity/epidemiology , Obesity/virology , Phenomics , Phenotype , Polymorphism, Single Nucleotide/genetics , SARS-CoV-2/pathogenicity , Thrombophlebitis/epidemiology , Thrombophlebitis/virology , Thrombosis/epidemiology , Thrombosis/virology
11.
Ann Vasc Surg ; 72: 209-215, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1385038

ABSTRACT

BACKGROUND: Both arterial and venous thrombotic events of the extremities occur in coronavirus disease 2019 (COVID-19) infection, but the etiology of these events remains unclear. This study sought to evaluate pathology specimens of COVID-19-positive patients postamputation, who were found to have Rutherford 3 acute limb ischemia requiring amputation. METHODS: A retrospective review was performed of all vascular surgery emergency room and inpatient consultations in patients who presented to the Mount Sinai Health System from March 26, 2020, to May 10, 2020. Pathology specimens were examined using hematoxylin and eosin stain. The specimens were assessed for the following: inflammatory cells associated with endothelium/apoptotic bodies, mononuclear cells, small vessel congestion, and lymphocytic endotheliitis. Of the specimens evaluated, 2 patients with a known history of peripheral vascular disease were excluded. RESULTS: Inflammatory cells associated with endothelium/apoptotic bodies were seen in all 4 patients and in 4 of 5 specimens. Mononuclear cells were found in 2 of 4 patients. Small vessel congestion was seen in all patients. Lymphocytic endotheliitis was seen in 1 of 4 patients. CONCLUSIONS: This study shows endotheliitis in amputation specimens of four patients with COVID-19 disease and Rutherford Class 3 acute limb ischemia. The findings in these patients is more likely an infectious angiitis because of COVID-19.


Subject(s)
Amputation , COVID-19/complications , Endothelium, Vascular/virology , Lower Extremity/blood supply , Lower Extremity/surgery , Thrombosis/surgery , Thrombosis/virology , Acute Disease , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Pandemics , Retrospective Studies , SARS-CoV-2
12.
J Leukoc Biol ; 109(1): 35-47, 2021 01.
Article in English | MEDLINE | ID: covidwho-1372745

ABSTRACT

The SARS-CoV-2 pandemic has led to hundreds of thousands of deaths and billions of dollars in economic damage. The immune response elicited from this virus is poorly understood. An alarming number of cases have arisen where COVID-19 patients develop complications on top of the symptoms already associated with SARS, such as thrombosis, injuries of vascular system, kidney, and liver, as well as Kawasaki disease. In this review, a bioinformatics approach was used to elucidate the immune response triggered by SARS-CoV-2 infection in primary human lung epithelial and transformed human lung alveolar. Additionally, examined the potential mechanism behind several complications that have been associated with COVID-19 and determined that a specific cytokine storm is leading to excessive neutrophil recruitment. These neutrophils are directly leading to thrombosis, organ damage, and complement activation via neutrophil extracellular trap release.


Subject(s)
COVID-19/immunology , SARS-CoV-2/immunology , Signal Transduction/immunology , Thrombosis/immunology , Vascular System Injuries/immunology , COVID-19/pathology , Cytokines/immunology , Humans , Mucocutaneous Lymph Node Syndrome/immunology , Mucocutaneous Lymph Node Syndrome/pathology , Mucocutaneous Lymph Node Syndrome/virology , Pulmonary Alveoli/immunology , Pulmonary Alveoli/pathology , Pulmonary Alveoli/virology , Thrombosis/pathology , Thrombosis/virology , Vascular System Injuries/pathology , Vascular System Injuries/virology
13.
Front Immunol ; 12: 700184, 2021.
Article in English | MEDLINE | ID: covidwho-1365542

ABSTRACT

Coronavirus disease 2019 (COVID-19), which has high incidence rates with rapid rate of transmission, is a pandemic that spread across the world, resulting in more than 3,000,000 deaths globally. Currently, several drugs have been used for the clinical treatment of COVID-19, such as antivirals (radecivir, baritinib), monoclonal antibodies (tocilizumab), and glucocorticoids (dexamethasone). Accumulating evidence indicates that long noncoding RNAs (lncRNAs) are essential regulators of virus infections and antiviral immune responses including biological processes that are involved in the regulation of COVID-19 and subsequent disease states. Upon viral infections, cellular lncRNAs directly regulate viral genes and influence viral replication and pathology through virus-mediated changes in the host transcriptome. Additionally, several host lncRNAs could help the occurrence of viral immune escape by inhibiting type I interferons (IFN-1), while others could up-regulate IFN-1 production to play an antiviral role. Consequently, understanding the expression and function of lncRNAs during severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection will provide insights into the development of lncRNA-based methods. In this review, we summarized the current findings of lncRNAs in the regulation of the strong inflammatory response, immune dysfunction and thrombosis induced by SARS-CoV-2 infection, discussed the underlying mechanisms, and highlighted the therapeutic challenges of COVID-19 treatment and its future research directions.


Subject(s)
COVID-19/immunology , Host Microbial Interactions/genetics , Immunity, Innate/genetics , RNA, Long Noncoding/metabolism , Thrombosis/immunology , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Biomarkers/analysis , COVID-19/complications , COVID-19/drug therapy , COVID-19/genetics , COVID-19 Testing/methods , Cytokines/genetics , Cytokines/metabolism , Gene Expression Regulation, Viral/drug effects , Gene Expression Regulation, Viral/immunology , Host Microbial Interactions/drug effects , Host Microbial Interactions/immunology , Humans , Immune Evasion/genetics , Pandemics/prevention & control , RNA, Long Noncoding/analysis , RNA, Long Noncoding/antagonists & inhibitors , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Signal Transduction/genetics , Signal Transduction/immunology , Thrombosis/genetics , Thrombosis/virology , Virus Replication/drug effects , Virus Replication/genetics , Virus Replication/immunology
14.
Am J Dermatopathol ; 43(8): 554-555, 2021 Aug 01.
Article in English | MEDLINE | ID: covidwho-1364851

ABSTRACT

ABSTRACT: "Severe acute respiratory syndrome coronavirus-2" (SARS-CoV-2) infection has variable described dermatologic manifestations. "COVID (coronavirus disease) toes" became a hallmark of the disease in young and largely asymptomatic patients, who may have negative test results for SARS-CoV-2. Pernio (chilblains)-like lesions are seen mostly in infected pediatric patients and are purple painful, frequently bilateral, ill-defined plaques with prominent inflammation on histological examination. In contrast to pernio-like presentation in children, critically ill adult patients with SARS-CoV-2 develop "purple" digits that may be sharply demarcated and may demonstrate asymmetric areas of ischemia. These 2 contrasting entities are sometimes grouped together as "COVID toes" due to some similarities in clinical appearance and presentation. Here, we summarize histopathologic examination from an autopsy, including the cutaneous lesions from the affected and normal contralateral toes and correlate them with systemic findings. In contrast to pernio-like lesions, the skin of the affected necrotic toes contained thrombi in vessels without prominent inflammation, suggestive of an embolic event. This is further supported by the clinical history of and autopsy findings of popliteal artery thrombus and multiple subsegmental pulmonary emboli. Our findings suggest that critically ill patients with SARS-CoV-2 have different pathological processes affecting skin at peripheral sites (ie, fingers, toes, ears, and nose), which may be due to thromboembolic events. The skin is a mirror of the body and skin pathology may shed light into overall pathogenesis of systemic illness and processes.


Subject(s)
COVID-19/complications , COVID-19/pathology , Thrombosis/virology , Toes/pathology , Autopsy , Humans , Male , Middle Aged , SARS-CoV-2 , Toes/blood supply
15.
Med Sci Monit ; 27: e930776, 2021 Oct 12.
Article in English | MEDLINE | ID: covidwho-1344551

ABSTRACT

During the coronavirus disease 2019 (COVID-19) pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, patients presented with COVID-19 pneumonia of varying severity. The phenomenon of severe hypoxemia without signs of respiratory distress is also known as silent or hidden hypoxemia. Although silent hypoxemia is not unique to pneumonia due to SARS-CoV-2 infection, this phenomenon is now recognized to be associated with severe COVID-19 pneumonia. Proper management of critically ill patients is the key to reducing mortality. Herein, we summarize the possible and rare factors contributing to silent hypoxemia in patients with COVID-19. Microvascular thrombosis causes dead space ventilation in the lungs, and the flow of pulmonary capillaries is reduced, which leads to an imbalance in the V/Q ratio. The dissociation curve of oxyhemoglobin shifts to the left and limits the release of oxygen to the tissue. SARS-CoV-2 interferes with the synthesis of hemoglobin and reduces the ability to carry oxygen. The accumulation of endogenous carbon monoxide and carboxyhemoglobin will reduce the total oxygen carrying capacity and interfere with pulse oxygen saturation readings. There are also some non-specific factors that cause the difference between pulse oximetry and oxygen partial pressure. We propose some potentially more effective clinical alternatives and recommendations for optimizing the clinical management processes of patients with COVID-19. This review aims to describe the prevalence of silent hypoxemia in COVID-19 pneumonia, to provide an update on what is known of the pathophysiology, and to highlight the importance of diagnosing silent hypoxemia in patients with COVID-19 pneumonia.


Subject(s)
COVID-19/metabolism , Hypoxia/virology , Pneumonia, Viral/virology , Asymptomatic Diseases/epidemiology , COVID-19/epidemiology , COVID-19/virology , Humans , Hypoxia/epidemiology , Hypoxia/metabolism , Lung/cytology , Lung/metabolism , Lung/virology , Microvessels/metabolism , Oximetry , Oxygen/metabolism , Pneumonia, Viral/metabolism , Prevalence , SARS-CoV-2/isolation & purification , Thrombosis/metabolism , Thrombosis/virology
16.
Int J Mol Sci ; 21(21)2020 Nov 03.
Article in English | MEDLINE | ID: covidwho-1344351

ABSTRACT

Progressive respiratory failure is seen as a major cause of death in severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2)-induced infection. Relatively little is known about the associated morphologic and molecular changes in the circulation of these patients. In particular, platelet and erythrocyte pathology might result in severe vascular issues, and the manifestations may include thrombotic complications. These thrombotic pathologies may be both extrapulmonary and intrapulmonary and may be central to respiratory failure. Previously, we reported the presence of amyloid microclots in the circulation of patients with coronavirus disease 2019 (COVID-19). Here, we investigate the presence of related circulating biomarkers, including C-reactive protein (CRP), serum ferritin, and P-selectin. These biomarkers are well-known to interact with, and cause pathology to, platelets and erythrocytes. We also study the structure of platelets and erythrocytes using fluorescence microscopy (using the markers PAC-1 and CD62PE) and scanning electron microscopy. Thromboelastography and viscometry were also used to study coagulation parameters and plasma viscosity. We conclude that structural pathologies found in platelets and erythrocytes, together with spontaneously formed amyloid microclots, may be central to vascular changes observed during COVID-19 progression, including thrombotic microangiopathy, diffuse intravascular coagulation, and large-vessel thrombosis, as well as ground-glass opacities in the lungs. Consequently, this clinical snapshot of COVID-19 strongly suggests that it is also a true vascular disease and considering it as such should form an essential part of a clinical treatment regime.


Subject(s)
Blood Platelets/pathology , Cardiovascular Diseases/virology , Coronavirus Infections/blood , Coronavirus Infections/pathology , Erythrocytes/pathology , Ferritins/blood , P-Selectin/blood , Pneumonia, Viral/blood , Pneumonia, Viral/pathology , Betacoronavirus/isolation & purification , Blood Coagulation/physiology , Blood Platelets/virology , COVID-19 , Cardiovascular Diseases/blood , Cardiovascular Diseases/pathology , Coronavirus Infections/virology , Erythrocytes/virology , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/virology , SARS-CoV-2 , Thrombosis/pathology , Thrombosis/virology
17.
Biosci Rep ; 41(8)2021 08 27.
Article in English | MEDLINE | ID: covidwho-1334001

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2)-induced infection, the cause of coronavirus disease 2019 (COVID-19), is characterized by unprecedented clinical pathologies. One of the most important pathologies, is hypercoagulation and microclots in the lungs of patients. Here we study the effect of isolated SARS-CoV-2 spike protein S1 subunit as potential inflammagen sui generis. Using scanning electron and fluorescence microscopy as well as mass spectrometry, we investigate the potential of this inflammagen to interact with platelets and fibrin(ogen) directly to cause blood hypercoagulation. Using platelet-poor plasma (PPP), we show that spike protein may interfere with blood flow. Mass spectrometry also showed that when spike protein S1 is added to healthy PPP, it results in structural changes to ß and γ fibrin(ogen), complement 3, and prothrombin. These proteins were substantially resistant to trypsinization, in the presence of spike protein S1. Here we suggest that, in part, the presence of spike protein in circulation may contribute to the hypercoagulation in COVID-19 positive patients and may cause substantial impairment of fibrinolysis. Such lytic impairment may result in the persistent large microclots we have noted here and previously in plasma samples of COVID-19 patients. This observation may have important clinical relevance in the treatment of hypercoagulability in COVID-19 patients.


Subject(s)
COVID-19/pathology , Fibrin/metabolism , Fibrinolysis/physiology , Spike Glycoprotein, Coronavirus/metabolism , Thrombosis/pathology , Adult , Aged , Amyloid/metabolism , Blood Platelets/metabolism , Complement C3/metabolism , Female , Fibrinogen/metabolism , Humans , Lung/pathology , Male , Microfluidic Analytical Techniques , Middle Aged , Prothrombin/metabolism , SARS-CoV-2/metabolism , Thrombosis/virology , Trypsin/metabolism
18.
Curr Opin Hematol ; 28(6): 445-453, 2021 11 01.
Article in English | MEDLINE | ID: covidwho-1299024

ABSTRACT

PURPOSE OF REVIEW: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus-2. Over the past year, COVID-19 has posed a significant threat to global health. Although the infection is associated with mild symptoms in many patients, a significant proportion of patients develop a prothrombotic state due to a combination of alterations in coagulation and immune cell function. The purpose of this review is to discuss the pathophysiological characteristics of COVID-19 that contribute to the immunothrombosis. RECENT FINDINGS: Endotheliopathy during COVID-19 results in increased multimeric von Willebrand factor release and the potential for increased platelet adhesion to the endothelium. In addition, decreased anticoagulant proteins on the surface of endothelial cells further alters the hemostatic balance. Soluble coagulation markers are also markedly dysregulated, including plasminogen activator inhibitor-1 and tissue factor, leading to COVID-19 induced coagulopathy. Platelet hyperreactivity results in increased platelet-neutrophil and -monocyte aggregates further exacerbating the coagulopathy observed during COVID-19. Finally, the COVID-19-induced cytokine storm primes neutrophils to release neutrophil extracellular traps, which trap platelets and prothrombotic proteins contributing to pulmonary thrombotic complications. SUMMARY: Immunothrombosis significantly contributes to the pathophysiology of COVID-19. Understanding the mechanisms behind COVID-19-induced coagulopathy will lead to future therapies for patients.


Subject(s)
Blood Coagulation Disorders/pathology , COVID-19/complications , SARS-CoV-2/isolation & purification , Thrombosis/pathology , Blood Coagulation Disorders/epidemiology , Blood Coagulation Disorders/virology , COVID-19/transmission , COVID-19/virology , Humans , Prognosis , Thrombosis/epidemiology , Thrombosis/virology
20.
Nutrients ; 13(7)2021 Jun 28.
Article in English | MEDLINE | ID: covidwho-1288966

ABSTRACT

SARS-CoV-2 infects the respiratory tract and leads to the disease entity, COVID-19. Accordingly, the lungs bear the greatest pathologic burden with the major cause of death being respiratory failure. However, organs remote from the initial site of infection (e.g., kidney, heart) are not spared, particularly in severe and fatal cases. Emerging evidence indicates that an excessive inflammatory response coupled with a diminished antiviral defense is pivotal in the initiation and development of COVID-19. A common finding in autopsy specimens is the presence of thrombi in the lungs as well as remote organs, indicative of immunothrombosis. Herein, the role of SARS-CoV-2 in lung inflammation and associated sequelae are reviewed with an emphasis on immunothrombosis. In as much as vitamin D is touted as a supplement to conventional therapies of COVID-19, the impact of this vitamin at various junctures of COVID-19 pathogenesis is also addressed.


Subject(s)
COVID-19/drug therapy , COVID-19/immunology , Inflammation/virology , Pneumonia/virology , Vitamin D/therapeutic use , Animals , COVID-19/virology , Extracellular Traps , Humans , Inflammation/drug therapy , Lung/pathology , Mice , Multiple Organ Failure/virology , Pneumonia/drug therapy , Respiratory Distress Syndrome/virology , SARS-CoV-2 , Thrombosis/immunology , Thrombosis/virology , Vitamins/therapeutic use
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