Coagulation Disorders in COVID-19: Role of Toll-like Receptors

COVID-19 related neurological manifestations in Parkinson's disease: has ferroptosis been a suspect?

A rising number of patient cases point to a probable link between SARS-CoV-2 infection and Parkinson's disease (PD), yet the mechanisms by which SARS-CoV-2 affects the brain and generates neuropsychiatric symptoms in COVID-19 patients remain unknown. Ferroptosis, a distinct iron-dependent non-apoptotic type of cell death characterized by lipid peroxidation and glutathione depletion, a key factor in neurological disorders. Ferroptosis may have a pathogenic role in COVID-19, according to recent findings, however its potential contributions to COVID-19-related PD have not yet been investigated. This review covers potential paths for SARS-CoV-2 infection of the brain. Among these putative processes, ferroptosis may contribute to the etiology of COVID-19-associated PD, potentially providing therapeutic methods.

How the immune response to the structural proteins of SARS-CoV-2 affects the retinal vascular endothelial cells: an immune thrombotic and/or endotheliopathy process with in silico modeling

Thrombotic events associated with SARS-CoV-2 at the vascular endothelium still remains unclear. The aim of the current study is to determine the relationship between cellular proteins on the (ocular) vascular endothelial surface and the immune thrombotic and/or endotheliopathy process elicited by SARS-CoV-2 using an in-silico modeling. The structural S (spike glycoprotein), N (nucleocapsid protein), M (membrane protein), and E (envelope protein) proteins, an accessory protein (ORF1ab) of SARS-CoV-2 and 158 cellular proteins associated with retinal vascular endothelial cell surface or structure were included in this study for comparison of three-dimensional (3D) structure and sequence. Sixty-nine of the retinal proteins were obtained from the Uniprot database. Remaining proteins not included in the database were included in the study after they were converted into 3D structures using the RaptorX web tool. Sequence and three-dimensional structure of SARS-COV-2 S, N, M, E, ORF1ab proteins and retinal vascular endothelial proteins were compared with mTM-align server. Proteins with significant similarity (score above 0.5) were validated with the TM-align web server. Immune and thrombosis-related protein-receptor interactions of similar proteins was checked with CABS-dock. We detected a high level of structural similarity between E protein and ACE, ACE2, LAT1, and TM9SF4 endothelial proteins. In addition, PECAM-1 was found to be structurally similar to ORF1ab and S protein. When we evaluated the likelihood/potential to stimulate an immune responses/a cytokine release, TLR-2 and TLR-3, which are highly susceptible to SARS-CoV2, showed a potential receptor-protein interaction with retinal vascular endothelial proteins. Our study demonstrates that SARS-CoV-2 proteins may have structural similarities with vascular endothelial proteins, and therefore, as immunological target sites, the counterpart proteins on the endothelial surface of many organs may also be secondarily affected by any immune response against SARS-CoV-2 structural proteins.

Epstein-Barr virus-acquired immunodeficiency in myalgic encephalomyelitis-Is it present in long COVID?

Both myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) and long COVID (LC) are characterized by similar immunological alterations, persistence of chronic viral infection, autoimmunity, chronic inflammatory state, viral reactivation, hypocortisolism, and microclot formation. They also present with similar symptoms such as asthenia, exercise intolerance, sleep disorders, cognitive dysfunction, and neurological and gastrointestinal complaints. In addition, both pathologies present Epstein-Barr virus (EBV) reactivation, indicating the possibility of this virus being the link between both pathologies. Therefore, we propose that latency and recurrent EBV reactivation could generate an acquired immunodeficiency syndrome in three steps: first, an acquired EBV immunodeficiency develops in individuals with "weak" EBV HLA-II haplotypes, which prevents the control of latency I cells. Second, ectopic lymphoid structures with EBV latency form in different tissues (including the CNS), promoting inflammatory responses and further impairment of cell-mediated immunity. Finally, immune exhaustion occurs due to chronic exposure to viral antigens, with consolidation of the disease. In the case of LC, prior to the first step, there is the possibility of previous SARS-CoV-2 infection in individuals with "weak" HLA-II haplotypes against this virus and/or EBV.

Coagulopathy and thromboembolic events a pathogenic mechanism of COVID-19 associated with mortality: An updated review

During 2019, the SARS-CoV-2 emerged from China, and during months, COVID-19 spread in many countries around the world. The expanding data about pathogenesis of this virus could elucidate the exact mechanism by which COVID-19 caused death in humans. One of the pathogenic mechanisms of this disease is coagulation. Coagulation disorders that affect both venous and arterial systems occur in patients with COVID-19. The possible mechanism involved in the coagulation could be excessive inflammation induced by SARS-CoV-2. However, it is not yet clear well how SARS-CoV-2 promotes coagulopathy. However, some factors, such as pulmonary endothelial cell damage and some anticoagulant system disorders, are assumed to have an important role. In this study, we assessed conducted studies about COVID-19-induced coagulopathy to obtain clearer vision of the wide range of manifestations and possible pathogenesis mechanisms.

Thromboprophylaxis for Coagulopathy Related to COVID-19 in Pediatrics: A Narrative Review

In addition to harming the respiratory system, COVID-19 can affect multiple organs. Children may develop a specific complication of COVID-19 called multisystem inflammatory syndrome in children (MIS-C) which could influence the vascular system of children and cause multiple coagulopathies in the body. Information on the use of thromboprophylaxis in this condition was collected via the review of various articles. In general, different factors in immune system responses can trigger the initiation of thrombotic events. Studies have shown that starting anticoagulant prophylaxis, which contributes to decreased thrombotic events, is dependent on the patient's condition and D-dimer levels. However, further studies on pediatric populations are needed to establish the role of anticoagulants in children with this condition.

Risk factors predicting disease severity and mortality in coronavirus disease 2019 Saudi Arabian patients

CONTEXT

Coronavirus disease 2019 (COVID-19) became a global pandemic that may be associated with significant associated risk factors.

AIMS

The aim of this study was to evaluate the factors predisposing risk to death in COVID-19 patients.

SETTINGS AND DESIGN

This is a retrospective study that presents the demographic, clinical presentation, and laboratory findings on our patients to determine risk factors contributing to their COVID-19 outcome.

METHODS

We used logistic regression (odds ratios) to examine associations between clinical findings and risk of death in COVID-19 patients. All analyses were done using STATA 15.

RESULTS

A total of 206 COVID-19 patients were investigated, 28 of them died, and 178 survived. Expired patients were older (74.04 ± 14.45 vs. 55.56 ± 18.41 in those who survived) and mainly of male gender (75% vs. 42% in those who survived). The following factors were strong predictors of death: hypertension (OR: 5.48, 95% CI: 2.10-13.59, P < 0.001), cardiac disease (OR: 5.08, 95% CI: 1.88-13.74, P = 0.001), and hospital admission (OR: 39.75, 95% CI: 5.28-299.12, P < 0.001). In addition, blood group B was more frequent in expired patients (OR: 2.27, 95% CI: 0.78-5.95, P = 0.065).

CONCLUSIONS

Our work adds to the current knowledge about the factors predisposing to death in COVID-19 patient. In our cohort, expired patients were of older age and male gender plus they were more likely to have hypertension, cardiac disease, and hospital severe disease. These factors might be used to evaluate risk of death in patients recently diagnosed of COVID-19.

Study of Coagulation Disorders and the Prevalence of Their Related Symptoms among COVID-19 Patients in Al-Jouf Region, Saudi Arabia during the COVID-19 Pandemic

Introduction: The coronavirus (COVID-19) has affected millions of people around the world. COVID-19 patients, particularly those with the critical illness, have coagulation abnormalities, thrombocytopenia, and a high prevalence of intravascular thrombosis. Objectives: This work aims to assess the prevalence of coagulation disorders and their related symptoms among COVID-19 patients in the Al-Jouf region of Saudi Arabia. Subjects and methods: We conducted a retrospective study on 160 COVID-19 patients. Data were collected from the medical records department of King Abdulaziz Specialist Hospital, Sakaka, Al-Jouf, Saudi Arabia. The socio-demographic data, risk factors, coagulation profile investigation results, symptom and sign data related to coagulation disorders, and disease morbidity and mortality for COVID-19 patients were extracted from medical records, and the data were stored confidentially. Results: Males represented the highest prevalence of COVID-19 infection at 65%; 29% were aged 60 or over; 28% were smokers; and 36% were suffering from chronic diseases, with diabetes mellitus representing the highest prevalence. Positive D-dimer results occurred in 29% of cases, with abnormal platelet counts in 26%. Conclusion: Our findings confirm that the dysregulation of the coagulation cascade and the subsequent occurrence of coagulation disorders are common in coronavirus infections. The results show absolute values, not increases over normal values; thus, it is hard to justify increased risk and presence based on the presented data.

Molecular Pathogenesis of Fibrosis, Thrombosis and Surfactant Dysfunction in the Lungs of Severe COVID-19 Patients

The global scope and scale of the SARS-CoV-2 pandemic led to huge amounts of important data from clinical observations and experimental analyses being collected, in particular, regarding the long-term impact of COVID-19 on lung tissue. Visible changes in lung tissue mainly relate to the destruction of the alveolar architecture, dense cellularity, and pulmonary fibrosis with myofibroblast proliferation and collagen deposition. These changes are the result of infection, mainly with virus variants from the first pandemic waves (Alpha to Delta). In addition, proper regulation of immune responses to pathogenic viral stimuli is critical for the control of and recovery from tissue/organ damage, including in the lungs. We can distinguish three main processes in the lungs during SARS-CoV-2 infection: damage or deficiency of the pulmonary surfactant, coagulation processes, and fibrosis. Understanding the molecular basis of these processes is extremely important in the context of elucidating all pathologies occurring after virus entry. In the present review, data on the abovementioned three biochemical processes that lead to pathological changes are gathered together and discussed. Systematization of the knowledge is necessary to explore the three key pathways in lung tissue after SARS-CoV-2 virus infection as a result of a prolonged and intense inflammatory process in the context of pulmonary fibrosis, hemostatic disorders, and disturbances in the structure and/or metabolism of the surfactant. Despite the fact that the new Omicron variant does not affect the lungs as much as the previous variants, we cannot ignore the fact that other new mutations and emerging variants will not cause serious damage to the lung tissue. In the future, this review will be helpful to stratify the risk of serious complications in patients, to improve COVID-19 treatment outcomes, and to select those who may develop complications before clinical manifestation.

The RAAS Axis and SARS-CoV-2: From Oral to Systemic Manifestations

One of the essential regulators of arterial blood pressure, the renin-angiotensin-aldosterone system (RAAS) seems to be one of the most complex mechanisms in the human body. Since the discovery of its key components and their actions, new substances and functions are still being unraveled. The main pathway begins with the secretion of renin in the kidney and culminates with the synthesis of angiotensin II (Ang II)-a strong vasoconstrictor-thanks to the angiotensin-converting enzyme (ACE). Research conducted in 2000 identified another enzyme, named ACE2, that converts Ang II into Ang-(1-7), a heptapeptide with opposing effects to those of Ang II: vasodilation and anti-inflammatory properties. This particular enzyme became of paramount importance during the last two decades, as a result of the confrontation of the human race with life-threatening epidemics. Multiple studies have been performed in order to uncover the link between ACE2 and human coronaviruses, the results of which we systemized in order to create an overview of the pathogenic mechanism. Human coronaviruses, such as SARS-CoV and SARS-CoV-2, attach to ACE2 via their spike proteins (S), causing the destruction of the enzyme. Because ACE2 limits the production of Ang II (by converting it into Ang-(1-7)), its destruction leads to a dysregulated inflammatory response. The purpose of this review is to decipher the complex pathophysiological mechanisms underlying the multiorgan complications (oral, cardiac, pulmonary, systemic) that appear as a result of the interaction of the SARS CoV-2 virus with the angiotensin-converting enzyme type 2.

Spontaneous spinal subdural hematoma in COVID-19 patient: Croatian national COVID hospital experience

Background:

Spontaneous spinal subdural hematoma (SSDH) is a rare condition and causes of acute spinal cord compression, with symptoms varying from mild to severe neurological deficit. SSDH could occur as a consequence of posttraumatic, iatrogenic, or spontaneous causes, including underlying arteriovenous malformations, tumors, or coagulation disorder. Due to its rarity, it is difficult to establish standardized treatment. We present a rare case of SSDH in COVID-19 patient and course of treatment in COVID hospital.

Case Description:

A 71-year-old female patient was admitted due to instability, weakness of the left leg, and intensive pain in the upper part of thoracic spine as well as mild respiratory symptoms of COVID-19. She was not on pronounced anticoagulant therapy and her coagulogram at admission was within normal range. MRI revealed acute subdural hematoma at the level C VII to Th III compressing the spinal cord. The patient underwent a decompressive Th I and Th II laminectomy and hematoma evacuation. Post-operative MRI revealed a satisfactory decompression and re-expansion of the spinal cord. COVID-19 symptoms remained mild.

Conclusion:

SSDH represents a neurological emergency, possibly leading to significant deficit and requires urgent recognition and treatment. One of the main difficulties when diagnosing is to consider such condition when there is no history of anticoagulant treatment or previous trauma. Since high incidence of coagulation abnormalities and thromboembolic events was described COVID-19 patients, when considering the pathology of the central nervous system, the bleeding within it due to COVID-19 should be taken into account, in both brain and spine.

Predictive ability of viscoelastic testing using ClotPro® for short-term outcome in patients with severe Covid-19 ARDS with or without ECMO therapy: a retrospective study

BACKGROUND

SARS-CoV-2 infections are suspected to trigger the coagulation system through various pathways leading to a high incidence of thromboembolic complications, hypercoagulation and impaired fibrinolytic capacity were previously identified as potentially mechanisms. A reliable diagnostic tool for detecting both is still under discussion. This retrospective study is aimed to examine the prognostic relevance of early viscoelastic testing compared to conventional laboratory tests in COVID-19 patients with acute respiratory distress syndrome (ARDS).

METHODS

All mechanically ventilated patients with COVID-19 related ARDS treated in our intensive care unit (ICU) between January and March 2021 were included in this study. Viscoelastic testing (VET) was performed using the ClotPro® system after admission to our ICU. Prevalence of thromboembolic events was observed by standardized screening for venous and pulmonary thromboembolism using complete compression ultrasound and thoracic computed tomography pulmonary angiography at ICU admission, respectively. We examined associations between the severity of ARDS at admission to our ICU, in-hospital mortality and the incidence of thromboembolic events comparing conventional laboratory analysis and VET. ECMO related coagulopathy was investigated in a subgroup analysis. The data were analyzed using the Mann-Whitney U test.

RESULTS

Of 55 patients enrolled in this study, 22 patients required treatment with ECMO. Thromboembolic complications occurred in 51% of all patients. Overall hospital mortality was 55%. In patients with thromboembolic complications, signs of reduced fibrinolytic capacity could be detected in the TPA assay with prolonged lysis time, median 460 s (IQR 350-560) vs 359 s (IQR 287-521, p = 0.073). Patients with moderate to severe ARDS at admission to our ICU showed increased maximum clot firmness as a sign of hypercoagulation in the EX-test (70 vs 67 mm, p < 0.05), FIB-test (35 vs 24 mm, p < 0.05) and TPA-test (52 vs 36 mm, p < 0.05) as well as higher values of inflammatory markers (CRP, PCT and IL6). ECMO patients suffered more frequently from bleeding complications (32% vs 15%).

CONCLUSION

Although, the predictive value for thromboembolic complications or mortality seems limited, point-of-care viscoelastic coagulation testing might be useful in detecting hypercoagulable states and impaired fibrinolysis in critically ill COVID-19 ARDS patients and could be helpful in identifying patients with a potentially very severe course of the disease.

Subchronic Toxicity Study of Alternanthera philoxeroides in Swiss Albino Mice Having Antioxidant and Anticoagulant Activities

Alternanthera philoxeroides, a tropical herb and edible vegetable, has been popular as a medicinal plant. Applying in vitro approach, we initially attempted to assess the phytochemicals, bioactive chemicals, as well as antioxidant and anticoagulant activities of this plant. Following that, the in vivo toxicological effects of methanolic extracts of A. philoxeroides using different doses on the kidney, heart, lung, liver, stomach, brain, and blood of female Swiss Albino mice were investigated. We estimated phytochemicals content as well as antioxidant activity through DPPH, NO, CUPRAC, and reducing power assays, followed by the anticoagulant activities of PT  and aPTT  and bioactive compounds using HPLC. To confirm the biocompatibility of A. philoxeroides extracts, histopathological and hematological parameters were examined in a mice model. Total phenol, flavonoid, and tannin content in A. philoxeroides was 181.75 ± 2.47 mg/g, 101.5 ± 3 .53 mg/g, and 68.58 ± 0.80 mg/g, respectively. Furthermore, the HPLC study confirmed the presence of four phenolic compounds: catechin, tannic acid, gallic acid, and vanillic acid. The methanolic extract of A. philoxeroides showed considerable antioxidant activity in all four antioxidant assay methods when compared to the standard. In comparison to ascorbic acid, A. philoxeroides also demonstrated a minor concentration-dependent ferric and cupric reduction activity. In vivo evaluation indicated that A. philoxeroides extracts (doses: 250, 500, and 1000 mg/kg) had no negative effects on the relative organ or body weight, or hematological indicators. Our study concluded that A. philoxeroides had significant antioxidant and anticoagulant activities and demonstrated no negative effects on the body or relative organ weight, histopathological, and hematological indices in the mouse model.

Coagulation Abnormalities and Management in Hospitalized Pediatric Patients With COVID-19

BACKGROUND

The incidence and severity of coagulation abnormalities have not been extensively studied in pediatric populations with coronavirus disease 2019 (COVID-19). Moreover, their association with an increased risk for thromboembolic events remains unclear, and there is a lack of evidence for optimal prophylactic antithrombotic management. The aim of our study was to present our experience in evaluation, management, and long-term outcomes of coagulation abnormalities in pediatric hospitalized patients with COVID-19.

METHODS

A prospective study was performed in all children hospitalized for COVID-19 during a 6-month period focusing on patients' coagulation abnormalities, the normalization of the coagulation profile with or without anticoagulation prophylaxis and the clinical outcome of the disease.

RESULTS

Two hundred twenty-three patients (median age: 11.4 months) were enrolled in the study. Coagulation abnormalities were detected in 92.4% of patients with increased D-dimer levels to be the most common abnormality detected in 84.3% of patients. Prophylactic anticoagulation was initiated only in 7 (3.1%) selected patients with severe COVID-19 and at least 2 risk factors for venous thromboembolism (VTE) and in all patients with previous history of VTE. Follow-up coagulation profile in 85 patients showed that changes over time had a tendency towards normalization irrespectively of the initiation of anticoagulant thromboprophylaxis. No thrombotic complications were observed 3 months upon discharge.

CONCLUSIONS

Although abnormal findings in coagulation profile were very common, they were not associated with risk for VTE even in severe cases. A trend of normalization early in the course of the disease was observed regardless of the use of anticoagulant thromboprophylaxis.

Gegen Qinlian pills alleviate carrageenan-induced thrombosis in mice model by regulating the HMGB1/NF-κB/NLRP3 signaling

BACKGROUND

The high incidence of thrombotic events is one of the clinical characteristics of coronavirus disease of 2019 (COVID-19), due to a hyperinflammatory response caused by the virus. Gegen Qinlian Pills (GQP) is a Traditional Chinese Medicine that is included in the Chinese Pharmacopoeia and played an important role in the clinical fight against COVID-19. Although GQP has shown the potential to treat thrombosis, there is no relevant research on its treatment of thrombosis so far.

HYPOTHESIS

We hypothesized that GQP may be capable inhibit inflammation-induced thrombosis.

STUDY DESIGN

We tested our hypothesis in a carrageenan-induced thrombosis mouse model in vivo and lipopolysaccharide (LPS)-induced human endothelial cells (HUVECs) in vitro.

METHODS

We used a carrageenan-induced mouse thrombus model to confirm the inhibitory effect of GQP on inflammation-induced thrombus. In vitro, studies in human umbilical vein endothelial cells (HUVECs) and in silico network pharmacology analyses were performed to reveal the underlying mechanisms of GQP and determine the main components, targets, and pathways of GQP, respectively.

RESULTS

Oral administration of 227.5 mg/kg, 445 mg/kg and 910 mg/kg of GQP significantly inhibited thrombi in the lung, liver, and tail and augmented tail blood flow of carrageenan-induced mice with reduced plasma tumor necrosis factor α (TNF-α) and diminished expression of high mobility group box 1 (HMGB1) in lung tissues. GQP ethanol extract (1, 2, or 5 μg/ml) also reduced the adhesion of platelets to LPS stimulated HUVECs. The TNF-α and the expression of HMGB1, nuclear factor kappa B (NF-κB), and NLR family pyrin domain containing 3 (NLRP3) in LPS stimulated HUVECs were also attenuated. Moreover, we analyzed the components of GQP and inferred the main targets, biological processes, and pathways of GQP in the treatment of inflammation-induced thrombosis through network pharmacology.

CONCLUSION

Overall, we demonstrated that GQP could reduce inflammation-induced thrombosis by inhibiting HMGB1/NFκB/NLRP3 signaling and provided an accurate explanation for the multi-target, multi-function mechanism of GQP in the treatment of thromboinflammation, and provides a reference for the clinical usage of GQP.

The Association between Protein C and Antithrombin III Levels with the Severity of Coronavirus Disease-2019 Symptoms

BACKGROUND: Coronavirus disease-2019 (COVID-19) has various symptoms ranging from mild to critical. Hypercoagulation state is often observed in severe and critical COVID-19. Both coagulation and inflammation are interrelated and amplifying each other, with protein C and antithrombin (AT) III as two important mediators. OBJECTIVE: To determine the association between protein C and AT III levels with the severity of COVID-19 symptoms. METHODS: This analytical study was conducted at Haji Adam Malik Hospital from April to July 2021. Subjects were obtained by consecutive sampling method. Inclusion criteria were patients with confirmed COVID-19 using RT-PCR and willing to participate. Subjects were divided into 2 groups: mild-moderate and severe-critical symptom groups. Demographic and blood sample were obtained from each subject. Blood samples underwent examination for leukocyte, thrombocyte, PT, aPTT, protein C, and AT III. RESULTS: A total of 50 patients were obtained with female domination (58%) and mean age of 41.44 (SD 20.90) years. Most subjects (86%) were in mild-moderate symptom group. There were significant differences in the level of protein C and AT III in both group (p= 0.029 and 0.034, respectively). Using the cut-off values for protein C of 5.36 ng/mL and AT III of 45.6%, subjects who had mediators level below the value tend to develop severe and critical symptoms compared to their counterparts (OR= 5.769 and 6.458, respectively). CONCLUSION: Protein C and AT III are associated with severity of COVID-19 symptoms. Lower protein C and AT III levels increase the risk for developing severe and critical symptoms.

Toll-like receptor 4 in COVID-19: friend or foe?

Toll-like receptor 4, an innate immune sensor, is one of the key ‘fate-deciding’ regulators of immunity as well as COVID-19 immunopathogenesis. Suitable targeting of Toll-like receptor 4 appears to be an effective strategy to counteract the pandemic.

Potential value of pharmacological agents acting on toll-like receptor (TLR) 7 and/or TLR8 in COVID-19

The COVID-19 pandemic is an ongoing global pandemic of coronavirus disease 2019 as an atypical type of viral pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Many potential pharmacotherapies are currently being investigated against this disease. This article points to and justifies, the importance of investigating the potential therapeutic value of pharmacological agents acting on Toll-like Receptor (TLR) 7 and/or TLR8 as double-edged swords combating COVID-19. Induction of TLR7 and/or TLR8 may be investigated as a strategy to stimulate immunity and may be added to anti-COVID19 vaccines to cope with their current viral escape challenge. TLR7 stimulation may not only help viral clearance through Th1 antiviral responses but may also provide beneficial broncho- and vaso-dilatory, as well as, anti-inflammatory effects. Pharmacological compounds acting as TLR7 and/or TLR8 agonists may be of value if used by frontline healthcare workers with comorbidities who demonstrate mild symptoms of the disease. On the other hand, TLR7 and/or TLR8 antagonists may be used in combination with immune-modulatory/anti-inflammatory drugs in severe cases of the disease, with potential synergistic effects that could also help in reducing the doses of such therapies, and consequently their adverse effects.

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There is potential value in development of TLR7/8 agonists/antagonists as double-edged swords combating COVID-19.

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TLR7/8 agonists, as immune-stimulants in mild disease, may also be added to preventive vaccines acting against viral escape.

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TLR7/8 antagonists may be combined with immune-suppressants in severe cases for potential synergism and minimized toxicity.

Thrombocytopathy vs Platelet hyper-reactivity in COVID-19: diverse pathologies, disease outcomes and therapeutic implications

Coagulopathy is an evident complication of COVID-19 with predominance of a prothrombotic state. Platelet activation plays a key role. The terms "hyper-reactivity" and "hyperactivity" used in recent literature may not be clear or sufficient to explain the pathological events involved in COVID-related thrombosis (CRT). Inflammation may play a bigger role compared to thrombosis in COVID-related mortality because a smaller percentage of patients with COVID-19 die due to direct effects of thrombosis. Not all COVID-19 patients have thrombocytopenia and a few show thrombocytosis. We believe the platelet pathology is more complex than just activation or hyper-activation, particularly due to the platelets' role in inflammation. Understanding the pathology and consequences of platelets' role may help optimize management strategies and diminish CRT-associated morbidity and mortality. In this viewpoint report, we examine the published evidence of platelet hyper-reactivity in COVID-19 with a focused analysis of the key pathologies, diverse alterations, disease outcomes, and therapeutic targets. We believe that COVID-19 is a disease of inflammation and pathologic platelets, and based on the complexity and diverse pathologies, we propose the term "thrombocytopathy" as a more reflective term of the platelets' involvement in COVID-19. In our opinion, thrombocytopathy is the unpredictable pathologic alterations of platelets in function, morphology and number, caused by different factors with a variety of presentations.

Demyelination as a result of an immune response in patients with COVID-19

The coronavirus disease of 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus-2 (SARS CoV-2), that already appeared as a global pandemic. Presentation of the disease often includes upper respiratory symptoms like dry cough, dyspnea, chest pain, and rhinorrhea that can develop to respiratory failure, needing intubation. Furthermore, the occurrence of acute and subacute neurological manifestations such as stroke, encephalitis, headache, and seizures are frequently stated in patients with COVID-19. One of the reported neurological complications of severe COVID-19 is the demolition of the myelin sheath. Indeed, the complex immunological dysfunction provides a substrate for the development of demyelination. Nevertheless, few published reports in the literature describe demyelination in subjects with COVID-19. In this short narrative review, we discuss probable pathological mechanisms that may trigger demyelination in patients with SARS-CoV-2 infection and summarize the clinical evidence, confirming SARS-CoV-2 condition as a risk factor for the destruction of myelin.

Glycyrrhizic Acid for COVID-19: Findings of Targeting Pivotal Inflammatory Pathways Triggered by SARS-CoV-2

Background: Coronavirus disease 2019 (COVID-19) is now a worldwide public health crisis. The causative pathogen is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Novel therapeutic agents are desperately needed. Because of the frequent mutations in the virus and its ability to cause cytokine storms, targeting the viral proteins has some drawbacks. Targeting cellular factors or pivotal inflammatory pathways triggered by SARS-CoV-2 may produce a broader range of therapies. Glycyrrhizic acid (GA) might be beneficial against SARS-CoV-2 because of its anti-inflammatory and antiviral characteristics and possible ability to regulate crucial host factors. However, the mechanism underlying how GA regulates host factors remains to be determined.

Methods: In our report, we conducted a bioinformatics analysis to identify possible GA targets, biological functions, protein-protein interactions, transcription-factor-gene interactions, transcription-factor-miRNA coregulatory networks, and the signaling pathways of GA against COVID-19.

Results: Protein-protein interactions and network analysis showed that ICAM1, MMP9, TLR2, and SOCS3 had higher degree values, which may be key targets of GA for COVID-19. GO analysis indicated that the response to reactive oxygen species was significantly enriched. Pathway enrichment analysis showed that the IL-17, IL-6, TNF-α, IFN signals, complement system, and growth factor receptor signaling are the main pathways. The interactions of TF genes and miRNA with common targets and the activity of TFs were also recognized.

Conclusions: GA may inhibit COVID-19 through its anti-oxidant, anti-viral, and anti-inflammatory effects, and its ability to activate the immune system, and targeted therapy for those pathways is a predominant strategy to inhibit the cytokine storms triggered by SARS-CoV-2 infection.

Strategies to DAMPen COVID-19-mediated lung and systemic inflammation and vascular injury

Approximately 15%-20% of patients infected with SARS-CoV-2 coronavirus (COVID-19) progress beyond mild and self-limited disease to require supplemental oxygen for severe pneumonia; 5% of COVID-19-infected patients further develop acute respiratory distress syndrome (ARDS) and multiorgan failure. Despite mortality rates surpassing 40%, key insights into COVID-19-induced ARDS pathology have not been fully elucidated and multiple unmet needs remain. This review focuses on the unmet need for effective therapies that target unchecked innate immunity-driven inflammation which drives unchecked vascular permeability, multiorgan dysfunction and ARDS mortality. Additional unmet needs including the lack of insights into factors predicting pathogenic hyperinflammatory viral host responses, limited approaches to address the vast disease heterogeneity in ARDS, and the absence of clinically-useful ARDS biomarkers. We review unmet needs persisting in COVID-19-induced ARDS in the context of the potential role for damage-associated molecular pattern proteins in lung and systemic hyperinflammatory host responses to SARS-CoV-2 infection that ultimately drive multiorgan dysfunction and ARDS mortality. Insights into promising stratification-enhancing, biomarker-based strategies in COVID-19 and non-COVID ARDS may enable the design of successful clinical trials of promising therapies.

Mechanisms of Immunothrombosis in Vaccine-Induced Thrombotic Thrombocytopenia (VITT) Compared to Natural SARS-CoV-2 Infection

Herein, we consider venous immunothrombotic mechanisms in SARS-CoV-2 infection and anti-SARS-CoV-2 DNA vaccination. Primary SARS-CoV-2 infection with systemic viral RNA release (RNAaemia) contributes to innate immune coagulation cascade activation, with both pulmonary and systemic immunothrombosis - including venous territory strokes. However, anti-SARS-CoV-2 adenoviral-vectored-DNA vaccines -initially shown for the ChAdOx1 vaccine-may rarely exhibit autoimmunity with autoantibodies to Platelet Factor-4 (PF4) that is termed Vaccine-Induced Thrombotic Thrombocytopenia (VITT), an entity pathophysiologically similar to Heparin-Induced Thrombocytopenia (HIT). The PF4 autoantigen is a polyanion molecule capable of independent interactions with negatively charged bacterial cellular wall, heparin and DNA molecules, thus linking intravascular innate immunity to both bacterial cell walls and pathogen-derived DNA. Crucially, negatively charged extracellular DNA is a powerful adjuvant that can break tolerance to positively charged nuclear histone proteins in many experimental autoimmunity settings, including SLE and scleroderma. Analogous to DNA-histone interactons, positively charged PF4-DNA complexes stimulate strong interferon responses via Toll-Like Receptor (TLR) 9 engagement. A chain of events following intramuscular adenoviral-vectored-DNA vaccine inoculation including microvascular damage; microbleeding and platelet activation with PF4 release, adenovirus cargo dispersement with DNA-PF4 engagement may rarely break immune tolerance, leading to rare PF4-directed autoimmunity. The VITT cavernous sinus cerebral and intestinal venous territory immunothrombosis proclivity may pertain to venous drainage of shared microbiotal-rich areas of the nose and in intestines that initiates local endovascular venous immunity by PF4/microbiotal engagement with PF4 autoantibody driven immunothrombosis reminiscent of HIT. According to the proposed model, any adenovirus-vectored-DNA vaccine could drive autoimmune VITT in susceptible individuals and alternative mechanism based on molecular mimicry, vaccine protein contaminants, adenovirus vector proteins, EDTA buffers or immunity against the viral spike protein are secondary factors. Hence, electrochemical DNA-PF4 interactions and PF4-heparin interactions, but at different locations, represent the common denominator in HIT and VITT related autoimmune-mediated thrombosis.

Potential COVID-19 Therapeutic Agents and Vaccines: An Evidence-Based Review

Since the early days of 2020, the severe acute respiratory syndrome coronavirus 2 pandemic has become a global health concern. Currently, some therapies and vaccines have received US Food and Drug Administration approval or emergency use authorization for the management of coronavirus disease 2019. According to the pathophysiology of the disease, several medications have been evaluated in different clinical conditions of the disease. Evidence-based reviewing and categorizing these medications can guide the clinicians to select the proper medications according to each patient's condition. Therefore, we performed this review to categorize the coronavirus disease 2019 potential therapeutics and vaccines.

COVID-19: Risk Factors Associated with Infectivity and Severity

COVID‐19 is highly transmissible; however, its severity varies from one individual to another. Variability among different isolates of the virus and among its receptor (ACE2) may contribute to this severity, but comorbidity plays a major role on disease prognosis. Many comorbidities have been reported to be associated with severe COVID‐19 patients. We have collected data from retrospective studies which include clinical and epidemiological features of patients and categorize them into severe/mild, ICU/non‐ICU and survivors/dead patients. In this review, we give an update about SARS‐CoV‐2 structure with emphasis on the possible reasons for the severity of the virus in patients. We also collected information and patients’ data to highlight the relation between COVID‐19 patients and comorbidities.

A Scoping Insight on Potential Prophylactics, Vaccines and Therapeutic Weaponry for the Ongoing Novel Coronavirus (COVID-19) Pandemic- A Comprehensive Review

The emergence of highly virulent CoVs (SARS-CoV-2), the etiologic agent of novel ongoing "COVID-19" pandemics has been marked as an alarming case of pneumonia posing a large global healthcare crisis of unprecedented magnitude. Currently, the COVID-19 outbreak has fueled an international demand in the biomedical field for the mitigation of the fast-spreading illness, all through the urgent deployment of safe, effective, and rational therapeutic strategies along with epidemiological control. Confronted with such contagious respiratory distress, the global population has taken significant steps towards a more robust strategy of containment and quarantine to halt the total number of positive cases but such a strategy can only delay the spread. A substantial number of potential vaccine candidates are undergoing multiple clinical trials to combat COVID-19 disease, includes live-attenuated, inactivated, viral-vectored based, sub-unit vaccines, DNA, mRNA, peptide, adjuvant, plant, and nanoparticle-based vaccines. However, there are no licensed anti-COVID-19 drugs/therapies or vaccines that have proven to work as more effective therapeutic candidates in open-label clinical trial studies. To counteract the infection (SARS-CoV-2), many people are under prolonged treatment of many chemical drugs that inhibit the PLpro activity (Ribavirin), viral proteases (Lopinavir/Ritonavir), RdRp activity (Favipiravir, Remdesivir), viral membrane fusion (Umifenovir, Chloroquine phosphate (CQ), Hydroxychloroquine phosphate (HCQ), IL-6 overexpression (Tocilizumab, Siltuximab, Sarilumab). Mesenchymal Stem Cell therapy and Convalescent Plasma Therapy have emerged as a promising therapeutic strategy against SARS-CoV-2 virion. On the other hand, repurposing previously designed antiviral agents with tolerable safety profile and efficacy could be the only promising approach and fast response to the novel virion. In addition, research institutions and corporations have commenced the redesign of the available therapeutic strategy to manage the global crisis. Herein, we present succinct information on selected anti-COVID-19 therapeutic medications repurposed to combat SARS-CoV-2 infection. Finally, this review will provide exhaustive detail on recent prophylactic strategies and ongoing clinical trials to curb this deadly pandemic, outlining the major therapeutic areas for researchers to step in.

Epigenetic underpinnings of inflammation: Connecting the dots between pulmonary diseases, lung cancer and COVID-19

Inflammation is an essential component of several respiratory diseases, such as chronic obstructive pulmonary disease (COPD), asthma and acute respiratory distress syndrome (ARDS). It is central to lung cancer, the leading cancer in terms of associated mortality that has affected millions of individuals worldwide. Inflammation and pulmonary manifestations are also the major causes of COVID-19 related deaths. Acute hyperinflammation plays an important role in the COVID-19 disease progression and severity, and development of protective immunity against the virus is greatly sought. Further, the severity of COVID-19 is greatly enhanced in lung cancer patients, probably due to the genes such as ACE2, TMPRSS2, PAI-1 and furin that are commonly involved in cancer progression as well as SAR-CoV-2 infection. The importance of inflammation in pulmonary manifestations, cancer and COVID-19 calls for a closer look at the underlying processes, particularly the associated increase in IL-6 and other cytokines, the dysregulation of immune cells and the coagulation pathway. Towards this end, several reports have identified epigenetic regulation of inflammation at different levels. Expression of several key inflammation-related cytokines, chemokines and other genes is affected by methylation and acetylation while non-coding RNAs, including microRNAs as well as long non-coding RNAs, also affect the overall inflammatory responses. Select miRNAs can regulate inflammation in COVID-19 infection, lung cancer as well as other inflammatory lung diseases, and can serve as epigenetic links that can be therapeutically targeted. Furthermore, epigenetic changes also mediate the environmental factors-induced inflammation. Therefore, a better understanding of epigenetic regulation of inflammation can potentially help develop novel strategies to prevent, diagnose and treat chronic pulmonary diseases, lung cancer and COVID-19.

Coagulative Disorders in Critically Ill COVID-19 Patients with Acute Distress Respiratory Syndrome: A Critical Review

In critically ill patients with acute respiratory distress syndrome (ARDS) coronavirus disease 2019 (COVID-19), a high incidence of thromboembolic and hemorrhagic events is reported. COVID-19 may lead to impairment of the coagulation cascade, with an imbalance in platelet function and the regulatory mechanisms of coagulation and fibrinolysis. Clinical manifestations vary from a rise in laboratory markers and subclinical microthrombi to thromboembolic events, bleeding, and disseminated intravascular coagulation. After an inflammatory trigger, the mechanism for activation of the coagulation cascade in COVID-19 is the tissue factor pathway, which causes endotoxin and tumor necrosis factor-mediated production of interleukins and platelet activation. The consequent massive infiltration of activated platelets may be responsible for inflammatory infiltrates in the endothelial space, as well as thrombocytopenia. The variety of clinical presentations of the coagulopathy confronts the clinician with the difficult questions of whether and how to provide optimal supportive care. In addition to coagulation tests, advanced laboratory tests such as protein C, protein S, antithrombin, tissue factor pathway inhibitors, D-dimers, activated factor Xa, and quantification of specific coagulation factors can be useful, as can thromboelastography or thromboelastometry. Treatment should be tailored, focusing on the estimated risk of bleeding and thrombosis. The aim of this review is to explore the pathophysiology and clinical evidence of coagulation disorders in severe ARDS-related COVID-19 patients.

Neurological and Neuropsychological Changes Associated with SARS-CoV-2 Infection: New Observations, New Mechanisms

SARS-CoV-2 infects cells through angiotensin-converting enzyme 2 (ACE2), a ubiquitous receptor that interacts with the virus' surface S glycoprotein. Recent reports show that the virus affects the central nervous system (CNS) with symptoms and complications that include dizziness, altered consciousness, encephalitis, and even stroke. These can immerge as indirect immune effects due to increased cytokine production or via direct viral entry into brain tissue. The latter is possible through neuronal access via the olfactory bulb, hematogenous access through immune cells or directly across the blood-brain barrier (BBB), and through the brain's circumventricular organs characterized by their extensive and highly permeable capillaries. Last, the COVID-19 pandemic increases stress, depression, and anxiety within infected individuals, those in isolation, and high-risk populations like children, the elderly, and health workers. This review surveys the recent updates of CNS manifestations post SARS-CoV-2 infection along with possible mechanisms that lead to them.

Role of Tissue Factor in the Pathogenesis of COVID-19 and the Possible Ways to Inhibit It

COVID-19 (Coronavirus Disease 2019) is a highly contagious infection and associated with high mortality rates, primarily in elderly; patients with heart failure; high blood pressure; diabetes mellitus; and those who are smokers. These conditions are associated to increase in the level of the pulmonary epithelium expression of angiotensin-converting enzyme 2 (ACE-2), which is a recognized receptor of the S protein of the causative agent SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). Severe cases are manifested by parenchymal lung involvement with a significant inflammatory response and the development of microvascular thrombosis. Several factors have been involved in developing this prothrombotic state, including the inflammatory reaction itself with the participation of proinflammatory cytokines, endothelial dysfunction/endotheliitis, the presence of antiphospholipid antibodies, and possibly the tissue factor (TF) overexpression. ARS-Cov-19 ACE-2 down-regulation has been associated with an increase in angiotensin 2 (AT2). The action of proinflammatory cytokines, the increase in AT2 and the presence of antiphospholipid antibodies are known factors for TF activation and overexpression. It is very likely that the overexpression of TF in COVID-19 may be related to the pathogenesis of the disease, hence the importance of knowing the aspects related to this protein and the therapeutic strategies that can be derived. Different therapeutic strategies are being built to curb the expression of TF as a therapeutic target for various prothrombotic events; therefore, analyzing this treatment strategy for COVID-19-associated coagulopathy is rational. Medications such as celecoxib, cyclosporine or colchicine can impact on COVID-19, in addition to its anti-inflammatory effect, through inhibition of TF.