The Comprehensive Appraisal of COVID-19: Its' Clinical Panorama from Virology till Management and Beyond

Severe acute respiratory syndrome, caused by SARS-CoV-2 disease (COVID-19), was first reported in China, and has laid the entire globe at a standstill, with an uncertain future, and a possible economic disaster. The World Health Organization (WHO), on March 11th 2020, avowed COVID-19 a pandemic considering its global pervasiveness. The multi-dimensional challenges include the combat with present available treatment options while simultaneously hastening scientific research for the development of definitive therapeutics and vaccine for this pandemic. The research advancement related to earlier epidemics of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) by the same coronavirus family provides the understanding of basic and clinical virology, pathogenesis and therapeutics of SARS-CoV-2. The dearth of definitive therapeutics and vaccine ren-ders COVID-19 pandemic a public health challenge globally. This comprehensive review of virology, pathogenesis, and management will abet quarters of public health authorities and medical fraternity to better understand COVID-19.Copyright © 2020 Bentham Science Publishers.

Disparities in telemedicine use among stroke survivors: The experience of three tertiary stroke centers

Introduction: In response to the COVID-19 pandemic, outpatient stroke care delivery was rapidly transformed to telemedicine (TM) care through video (VTM) and telephone (TPH) visits around the world. We sought to evaluate the sociodemographic differences in TM use among stroke survivors. Methods: We conducted a retrospective chart review of stroke survivors evaluated at three tertiary stroke center clinics in the early period of the pandemic, 3/16/2020 till 7/31/2020. We compared the use of TM by demographics. The association between the use of TM and race/ethnicity was measured using the relative risk (RR) from a modified Poisson regression model adjusting for age, sex, insurance status, stroke type, visit type, and site. Results: A total of 2,024 individuals were included from UTHealth (n=878), MedStar Georgetown (n=269), and Columbia (n=877). Median age was 64 [IQR 52-74] and 53% were female. About half the patients had private insurance, 36% had Medicare and 15% had Medicaid. Two-thirds of the visits were established patients. TM accounted for 90% and the use of TM over office visits was primarily associated with site, not patients' characteristics. Among TM users, older age, non-White, and Medicaid were associated with lower VTM compared to TPH use. Black (aRR 0.90, 95% CI 0.85-0.95, p<0.001) and Hispanic patients (aRR 0.91, 95% CI 0.86 - 0.97, p=0.005) had 10% lower VTM use while Asian patients (aRR 0.98, 95% CI 0.90 - 1.06, p=0.56) had similar VTM use compared to White patients (Figure). Conclusions: In our diverse cohort, we found differences in TM visit type by race and insurance, with overall higher utilization among established patients. These findings suggest disparities in VTM access across different stroke populations. As VTM becomes an integral part of outpatient practice, steps to ensure equitable access are essential.

Suppression of fibrinolysis and hypercoagulability link lung injury and mortality in severe COVID-19

Background: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is marked by coagulopathy that may relate to disease severity. Aims: We sought to understand the link between coagulopathy and acute respiratory distress syndrome (ARDS) in critically ill patients with Coronavirus Disease 2019 (COVID-19). Methods: We prospectively evaluated coagulation factor-specific biomarkers by ELISA and activity assays, viscoelastic testing by rotational thromboelastometry (ROTEM), and clinical data in 56 critically ill patients with COVID-19. One and two-way analyses of variance were performed to uncover association of factor levels with mortality, ECMO-requirement, major thrombotic events, and ARDS severity by PaO2/FiO2 ratio. Results: Patients averaged 57.2 years in age. Twenty-five percent had a major thromboembolic event, 16% had a major hemorrhage, and 23% died. All patients displayed hypercoagulability on viscoelastic testing, although those requiring veno-venous extracorporeal membrane oxygenation (ECMO) also had signs of consumptive coagulopathy and more frequent hemorrhagic complications than ECMO-naïve patients. In all patients, plasminogen activator inhibitor-1 (PAI-1) levels were increased, and ROTEM-determined clot lysis limited despite increased D-dimer levels, consistent with fibrinolytic suppression. In patients with thromboembolic events, regardless of ECMO status, PAI-1, von Willebrand Factor (vWF), and factor VIII levels were elevated. Increased PAI-1 and vWF and decreased ADAMTS13 levels correlated with ARDS severity and mortality. Conclusions: Our study defines the relationship between COVID-19 associated coagulopathy and the severity of acute lung injury by describing elevation in markers of endotheliopathy in association with low PaO2/FiO2 ratios. We identified increased PAI-1 with ARDS severity and thrombotic events, implicating fibrinolytic suppression in the microcirculatory injury and subsequent micro-and macrovascular thrombosis of severe COVID-19. Further investigation into therapeutic approaches to limit endothelial injury is needed. Other items for consideration: The study was approved by the Duke Institutional Review Board (Pro00101196 and Pro00105315).

Generation of anticoagulant RNA aptamers targeting cofactors that inhibit clotting in normal and COVID-19 patientsamples

Background : Coagulation cascade cofactors are essential proteins that control homeostasis and are appealing targets for anticoagulants. However, targeting such proteins has been challenging due to their lack of an active site. Aims : Development of FV/FVa and FVIII-inhibiting aptamers as potent and reversible anticoagulants that can be used to aid (or replace) heparin for therapeutic anticoagulation. Reveal new mechanisms of cofactor inhibition. Methods : 2 ' F modified RNA Aptamers were identified via in vitro systematic evolution of ligand by exponential enrichment (SELEX) and post-SELEX truncation. Aptamer affinity was characterized by nitrocellulose filter binding assays and surface plasmon resonance. Aptamer bioactivity was analyzed using clotting assays and biochemical assays. Aptamers ' binding mechanism was determined using fluorescent anisotropy, fluorescence resonance energy transfer, dynamic light scattering, and molecular modeling. Results : An aptamer termed T18.3 binds to both human FV/FVa with K D ∼10 nM and prolongs aPTT in normal human plasma by 3.5-fold at a concentration of 500 nM. The aptamer inhibits membrane docking of FVa by binding to FV/FVa light chain, thereby reduces prothrombinase assembly and thrombin generation. Notably, the aptamer showed similar anticoagulant potency in normal, FV Leiden, and COVID-19 patient plasma. The aptamer also synergistically inhibits clotting with enoxaparin and can be rapidly reversed by protamine in in vitro assays. Another aptamer termed F8-3.1 binds to human FVIII with a K D of 0.67 nM and prolongs aPTT in normal human plasma by 1.9-fold at a concentration of 500 nM. F8-3.1 also has full cross-reactivity to canine FVIII (K D = 0.68 nM) and significantly prolongs the aPTT in canine and porcine plasma. Conclusions : The work describes the generation of aptamers targeting FV/FVa and FVIII that can achieve clinically relevant anticoagulant activity. These results not only demonstrate the feasibility of using cofactor-binding aptamers as therapeutic anticoagulants but also reveal a novel mechanism of aptamer-mediated protein inhibition by interrupting protein-membrane interactions.

Combining heparin with a FX/FXA aptamer to reduce thrombin generation in models of cardiopulmonary bypass andcovid-19 associated coagulopathy

Background : Unfractionated heparin (UFH) is the primary anticoagulant for highly procoagulant indications including cardiopulmonary bypass (CPB) and severe COVID-19. UFH is unable to fully inhibit thrombin generation increasing the risk for thrombo-inflammatory adverse events (AEs). We attempt to address this limitation by evaluating the FX/Xa aptamer, 11F7t. We hypothesized that combinations of UFH and 11F7t would achieve enhanced anticoagulation while minimizing thrombin generation in models of CPB and COVID-19 associated coagulopathy (CoAC). Aims : We determined optimal combinations of UFH and 11F7t that produced CPB-sufficient anticoagulation and minimized thrombin generation in whole blood in vitro and ex vivo models of CPB. Furthermore, we aimed to determine the utility of this anticoagulation strategy in addressing CoAC. Methods : We employed whole blood coagulation assays to determine the optimal doses of UFH and 11F7t. Fresh human blood was treated with UFH+11F7t combinations and continuously circulated in an ex vivo oxygenator circuit for 2 h to model CPB. Thereafter, thrombin generation was assessed using ELISAs. For CoAC studies, thrombin generation from severely ill COVID-19 patient plasma was determined using the Calibrated Automated Thrombogram (CAT) assay. Results : In in vitro and ex vivo models of CPB, a combined dose of 2 U/mL UFH with 2 μM 11F7t was able to achieve anticoagulation similar to the therapeutic dose of UFH (5 U/mL). Further investigation into thrombin generation with ex vivo experiments showed that the combinations of UFH and 11F7t are more effective than UFH alone at limiting thrombin generation (Figure 1). Similar anticoagulation and reduced thrombin generation was observed when blood from severely ill COVID-19 patients on heparin therapy was treated with 2 μM 11F7t (Figure 2). Conclusions : This study demonstrates that combining UFH with a FX/Xa aptamer produces potent anticoagulation with reduced thrombin generation and has the potential to address CPBassociated AEs and has potential utility in other procoagulant settings such as CoAC.

Elevated von willebrand factor in patients presenting with large-vessel occlusion stroke as first symptom of COVID-19 mirrors levels in patients with COVID-19 requiring icu-level care

Introduction: COVID-19 is a coagulopathic disease marked by elevated d-dimers, fibrinogen, and von Willebrand factor (vWF) levels accompanying arterial and venous thrombosis. While the majority of thrombotic events associated with COVID-19 occur in hospitalized patients, a subset of patients with minimal risk factors for CVA but with positive SARS-CoV-2 testing present with stroke as presumed first manifestation of infection. It is unclear if the pro-coagulant milieu present in patients requiring hospitalization for the respiratory complications of COVID-19 is the same as that of patients who present with stroke as first symptom of disease. Methods: Following emergent revascularization, clinical vWF levels were measured in patients presenting with stroke who tested positive for COVID-19. In parallel, plasma vWF levels from 28 patients with COVID-19 requiring ICU-level care and 8 healthy volunteers were measured via ELISA. Results: Three otherwise healthy patients between the ages of 45-55 years with positive test for SARS-CoV-2 presented with large-vessel stroke. By comparison, the average age of non-COVID stroke patients was 66 years. The consistency of the clots extracted through the aspirating catheter was dark, gelatinous throughout, without evidence of calcification, and distal thrombosis was noted minutes after revascularization. The vWF level for one patient was 345%, while the other two patients had vWF levels >400% of normal, exceeding the upper limit of detection of clinical assays. In the ICU cohort, 12 of 28 had thrombotic events during hospitalization. vWF levels were elevatedby a mean of 800% over healthy controls with a range of 230-1670%. Conclusions: vWF levels were markedly elevated in both ICU patients and stroke patients withCOVID-19 with an overlapping range of elevation over healthy controls. This suggests thatwidespread endothelial inflammation accompanies infection with SARS-CoV-2 even in the absenceof respiratory symptoms.