COVID-19-Associated Hyper-Fibrinolysis: Mechanism and Implementations

Risk Factors for Bleeding in Coronavirus Disease 2019 Patients on Extracorporeal Membrane Oxygenation and Effects of Transcatheter Arterial Embolization for Hemostasis

Purpose

To evaluate risk factors for bleeding events in coronavirus disease 2019 (COVID-19) patients on extracorporeal membrane oxygenation (ECMO) and to share the initial results of transcatheter arterial embolization (TAE) for hemostasis.

Material and Methods

Forty-three COVID-19 patients who received ECMO from May 2020 to September 2021 were enrolled in this study. Patients with sudden onset anemia immediately underwent computed tomography to assess bleeding. We compared laboratory data, duration of ECMO, hospitalization period, and fatality of patients' groups with and without significant hemorrhagic events using the chi-square test and Mann-Whitney U test. We also assessed the results of TAE in patients who received hemostasis.

Results

A total of 25 bleeding events occurred in 24 of the 43 patients. Age was a risk factor for bleeding events and fatality. The average duration of ECMO and hospitalization period were significantly longer in those with bleeding events (42.9 and 54.3 days) than in those without bleeding events (16.2 and 25.0 days) (p < 0.05). In addition, those with bleeding had higher fatality (45.8%) than those without (15.8%) (p < 0.05). Active extravasation was confirmed for 5 events in 4 of 24 patients. TAE was attempted and performed successfully in all but one of these four cases, in whom bleeding ceased spontaneously.

Conclusions

Elderly COVID-19 patients on ECMO had a greater risk of bleeding complications and fatal outcomes. TAE was effective in providing prompt hemostasis for patients who have the treatment indication.

Characterization of extracellular vesicles in COVID-19 infection during pregnancy

Introduction: SARS-CoV-2 infection may cause a severe inflammatory response, inflicting severe morbidity and mortality. This risk is modestly increased in pregnant patients. Despite the hypercoagulability and immunosuppression associated with pregnancy, most pregnant women experience a mild COVID-19 infection. Maternal extracellular vesicles (EVs) may interact with endothelial and immune components to facilitate a favorable disease course. This pilot study aimed to explore the characteristics of EVs released during COVID-19 infection occurring during the third trimester of pregnancy. Methods: In this prospective study, blood samples were obtained from 16 healthy non-pregnant (NP), 18 healthy-pregnant (HP), and 22 COVID-19 positive pregnant subjects (CoV-P). Disease course and pregnancy outcomes were assessed and EVs were characterized. Of note, limited volumes of sample acquired from the subjects made it necessary to use smaller and different subsets of samples for each analysis. Results: The majority (91%) of the COVID-19-pregnant subjects (18 mild and 2 moderate disease) experienced good pregnancy-related outcomes. EV concentrations were higher in healthy-pregnant subjects compared to non-pregnant subjects (p = 0.0041) and lower in COVID-19-pregnant subjects compared to healthy-pregnant subjects (p = 0.0150). CD63 exosome marker expression was higher in EVs of healthy-pregnant subjects and COVID-19-pregnant subjects compared to EVs of non-pregnant subjects (p = 0.0149, p = 0.0028, respectively). Similar levels of SARS-CoV-2 entry proteins (ACE-2 and TMPRSS2) were found in all three groups. Cytokine content increased in healthy-pregnant subject-EVs compared to non-pregnant EVs, while IL-2 and IL-6 levels were decreased in COVID-19-pregnant subject-EVs compared to healthy-pregnant subject-EVs (p = 0.043, p = 0.0390, respectively). CD8+, cytotoxic T-cell marker, was lower in non-pregnant EVs compared to healthy-pregnant subject-EVs and to COVID-19-pregnant subjects (p = 0.0108, p < 0.0001, respectively). COVID-19- pregnant subject-EVs demonstrated higher levels of platelet activation marker (CD62P) than non-pregnant (p = 0.0327) and healthy-pregnant subjects (p = 0.0365). Endothelial marker EV-CD144+ was lower in healthy-pregnant subjects versus non-pregnant subjects (p = 0.0093), but similar in COVID-19-pregnant and non-pregnant subjects. Other EVs' coagulation markers/activity, D-Dimer and fibrinogen levels were similar in healthy-pregnant subjects and COVID-19 positive pregnant subjects. Conclusion: COVID-19 positive pregnant subjects' EVs demonstrated an attenuated inflammatory response, with no additional activation of the coagulation system.

Fibrinolytic system and COVID-19: From an innovative view of epithelial ion transport

Lifeways of worldwide people have changed dramatically amid the coronavirus disease 2019 (COVID-19) pandemic, and public health is at stake currently. In the early stage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, fibrinolytic system is mostly inhibited, which is responsible for the development of hypofibrinolysis, promoting disseminated intravascular coagulation, hyaline membrane formation, and pulmonary edema. Whereas the common feature and risk factor at advanced stage is a large amount of fibrin degradation products, including D-dimer, the characteristic of hyperfibrinolysis. Plasmin can cleave both SARS-CoV-2 spike protein and γ subunit of epithelial sodium channel (ENaC), a critical element to edematous fluid clearance. In this review, we aim to sort out the role of fibrinolytic system in the pathogenesis of COVID-19, as well as provide the possible guidance in current treating methods. In addition, the abnormal regulation of ENaC in the occurrence of SARS-CoV-2 mediated hypofibrinolysis and hyperfibrinolysis are summarized, with the view of proposing an innovative view of epithelial ion transport in preventing the dysfunction of fibrinolytic system during the progress of COVID-19.

Extracellular Vesicles of COVID-19 Patients Reflect Inflammation, Thrombogenicity, and Disease Severity

Severe COVID-19 infections present with cytokine storms, hypercoagulation, and acute respiratory distress syndrome, with extracellular vesicles (EVs) being involved in coagulation and inflammation. This study aimed to determine whether coagulation profiles and EVs reflect COVID-19 disease severity. Thirty-six patients with symptomatic COVID-19 infection with mild/moderate/severe disease (12 in each group) were analyzed. Sixteen healthy individuals served as controls. Coagulation profiles and EV characteristics were tested by nanoparticle tracking analysis (NTA), flow cytometry, and Western blot. While coagulation factors VII, V, VIII, and vWF were comparable, significant differences were found in patients' D-Dimer/fibrinogen/free protein S levels compared to controls. Severe patients' EVs displayed higher percentages of small EVs (<150 nm) with increased expression of exosome marker CD63. Severe patients' EVs displayed high levels of platelet markers (CD41) and coagulation factors (tissue factor activity, endothelial protein C receptor). EVs of patients with moderate/severe disease expressed significantly higher levels of immune cell markers (CD4/CD8/CD14) and contained higher levels of IL-6. We demonstrated that EVs, but not the coagulation profile, may serve as biomarkers for COVID-19 severity. EVs demonstrated elevated levels of immune- and vascular-related markers in patients with moderate/severe disease, and may play a role in disease pathogenesis.

Post-Operative Bleeding Complications in a Periodontitis Patient Testing Positive for COVID-19

Recent scientific evidence states that a subset of COVID-19 patients may have a risk of increased bleeding tendency. This case report presents a healthy 38-year-old woman with generalized stage III, grade C periodontitis with an abnormal post-operative blood clot formation who tested positive for COVID-19 after a standard periodontal surgery. Previously, two periodontal surgeries proceeded without any complications and were considered standard. On day one after the third periodontal surgery the patient had no complaints. On day two the patient reported excess bleeding in the oral cavity from the operated area simultaneously with fever and loss of taste. On day three the patient was seen in our clinic; general malaise symptoms and bleeding tendency had started to decline and the patient received a COVID-19 PCR test. At day four the test resulted positive, and she reported no further complaints of intraoral bleeding. Six months later the taste of the patient was still distorted. For this patient with free medical anamnesis, we suggest that the patient had increased plasma levels of tissue plasminogen activator during the crucial postoperative period due to an acute COVID-19 infection. This led to increased plasmin levels with a hyper-fibrinolytic state as a consequence.

D-dimer: an analyte with increasing application in Covid-19 infection

INTRODUCTION

: D- Dimer levels from peripheral blood are increasingly used to assess various pathological conditions. Initially an area for haematologists, now this analyte is evaluated more extensively from many specialities of medicine. Covid-19 infection has not only added a new dimension to D-Dimer level assessment in this disease but has also shed newer lights to the underlying pathophysiological mechanisms for its elevation in this disease.

AREAS COVERED

Innate variability in measuring D- Dimer levels, Impact of various techniques in measuring D- Dimer, non availability of uniform controls and standards, molecular heterogeneity of the product, how it is produced. Reasons for raised D- Dimer in covid-19 infection. D- Dimer in other pathological states. Articles with relevant key words from 1990 searched in PubMed were utilized for review.

EXPERT OPINION

: D-Dimer has important application in diagnosis, prognosis, management and understanding various conditions. Its level can rise with increased coagulability of blood, sepsis, cytokine storm and snake bite etc. Renal function, age influences its reference ranges. Units of measurement, its expression varies in different reports needing international standardization. In Covid-19 infection its levels correlate with stage of the disease, pathology and complications.

Exploration of Human Serum Lipoprotein Supramolecular Phospholipids Using Statistical Heterospectroscopy in n-Dimensions (SHY-n): Identification of Potential Cardiovascular Risk Biomarkers Related to SARS-CoV-2 Infection

SARS-CoV-2 infection causes a significant reduction in lipoprotein-bound serum phospholipids give rise to supramolecular phospholipid composite (SPC) signals observed in diffusion and relaxation edited ¹H NMR spectra. To characterize the chemical structural components and compartmental location of SPC and to understand further its possible diagnostic properties, we applied a Statistical HeterospectroscopY in n-dimensions (SHY-n) approach. This involved statistically linking a series of orthogonal measurements made on the same samples, using independent analytical techniques and instruments, to identify the major individual phospholipid components giving rise to the SPC signals. Thus, an integrated model for SARS-CoV-2 positive and control adults is presented that relates three identified diagnostic subregions of the SPC signal envelope (SPC₁, SPC₂, and SPC₃) generated using diffusion and relaxation edited (DIRE) NMR spectroscopy to lipoprotein and lipid measurements obtained by in vitro diagnostic NMR spectroscopy and ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The SPC signals were then correlated sequentially with (a) total phospholipids in lipoprotein subfractions; (b) apolipoproteins B100, A1, and A2 in different lipoproteins and subcompartments; and (c) MS-measured total serum phosphatidylcholines present in the NMR detection range (i.e., PCs: 16.0,18.2; 18.0,18.1; 18.2,18.2; 16.0,18.1; 16.0,20.4; 18.0,18.2; 18.1,18.2), lysophosphatidylcholines (LPCs: 16.0 and 18.2), and sphingomyelin (SM 22.1). The SPC₃/SPC₂ ratio correlated strongly (r = 0.86) with the apolipoprotein B100/A1 ratio, a well-established marker of cardiovascular disease risk that is markedly elevated during acute SARS-CoV-2 infection. These data indicate the considerable potential of using a serum SPC measurement as a metric of cardiovascular risk based on a single NMR experiment. This is of specific interest in relation to understanding the potential for increased cardiovascular risk in COVID-19 patients and risk persistence in post-acute COVID-19 syndrome (PACS).

Is the Endothelium the Missing Link in the Pathophysiology and Treatment of COVID-19 Complications?

Patients with COVID-19 present a wide spectrum of disease severity, from asymptomatic cases in the majority to serious disease leading to critical care and even death. Clinically, four different scenarios occur within the typical disease timeline: first, an incubation and asymptomatic period; second, a stage with mild symptoms due mainly to the virus itself; third, in up to 20% of the patients, a stage with severe symptoms where a hyperinflammatory response with a cytokine storm driven by host immunity induces acute respiratory distress syndrome; and finally, a post-acute sequelae (PASC) phase, which present symptoms that can range from mild or annoying to actually quite incapacitating. Although the most common manifestation is acute respiratory failure of the lungs, other organs are also frequently involved. The clinical manifestations of the COVID-19 infection support a key role for endothelial dysfunction in the pathobiology of this condition. The virus enters into the organism via its interaction with angiotensin-converting enzyme 2-receptor that is present prominently in the alveoli, but also in endothelial cells, which can be directly infected by the virus. Cytokine release syndrome can also drive endothelial damage independently. Consequently, a distinctive feature of SARS-CoV-2 infection is vascular harm, with severe endothelial injury, widespread thrombosis, microangiopathy, and neo-angiogenesis in response to endothelial damage. Therefore, endothelial dysfunction seems to be the pathophysiological substrate for severe COVID-19 complications. Biomarkers of endothelial injury could constitute strong indicators of disease progression and severity. In addition, the endothelium could represent a very attractive target to both prevent and treat these complications. To establish an adequate therapy, the underlying pathophysiology and corresponding clinical stage should be clearly identified. In this review, the clinical features of COVID-19, the central role of the endothelium in COVID-19 and in other pathologies, and the potential of specific therapies aimed at protecting the endothelium in COVID-19 patients are addressed.

Anticoagulated de novo atrial flutter complicated by transitory ischemic attack in fatal COVID-19

SARS-CoV-2 may not only manifest as pneumonia (COVID-19) but also in other organs, including the brain (neuro-COVID). One of the cerebral complications of SARS-CoV-2 is ischemic stroke. Transitory ischemic attack (TIA) in a SARS-CoV-2 positive has not been reported. A 78-year-old poly-morbid male (diabetes, hypertension, and coronary heart disease), admitted for COVID-19, developed atrial flutter on hospital day (hd) 2. Anticoagulation with enoxaparin was started. On hd5, he experienced a TIA despite sufficient anticoagulation. The patient expired on hd28 due to multi-organ failure from sepsis due to superinfection with staphylococcus aureus. Infection with SARS-CoV-2 may be complicated by atrial flutter. Atrial flutter may be complicated by TIA despite sufficient anticoagulation, suggesting that standard anticoagulation may be insufficient to meet SARS-CoV-2-associated hypercoagulability syndrome. Forced anticoagulation and adequate antibiosis in poly-morbid SARS-CoV-2-infected patients with hypercoagulability and cytokine storm are warranted.

COVID-19: Vaccine Delivery System, Drug Repurposing and Application of Molecular Modeling Approach

The acute respiratory syndrome coronavirus (SARS-CoV-2) has spread across the world, resulting in a pandemic COVID-19 which is a human zoonotic disease that is caused by a novel coronavirus (CoV) strain thought to have originated in wild or captive bats in the initial COVID outbreak region. The global COVID-19 outbreak started in Guangdong Province, China's southernmost province. The global response to the COVID-19 pandemic has been hampered by the sheer number of infected people, many of whom need intensive care before succumbing to the disease. The epidemic is being handled by a combination of disease control by public health interventions and compassionate treatment for those who have been impacted. There is no clear anti-COVID-19 medication available at this time. However, the need to find medications that can turn the tide has led to the development of a number of investigational drugs as potential candidates for improving outcomes, especially in the severely and critically ill. Although many of these adjunctive medications are still being studied in clinical trials, professional organizations have attempted to define the circumstances in which their use is deemed off-label or compassionate. It is important to remind readers that new information about COVID-19's clinical features, treatment options, and outcomes is released on a regular basis. The mainstay of treatment remains optimized supportive care, and the therapeutic effectiveness of the subsequent agents is still being studied.

A comprehensive insight into the role of zinc deficiency in the renin-angiotensin and kinin-kallikrein system dysfunctions in COVID-19 patients

Hypozincemia is prevalent in severe acute respiratory syndrome coronavirus-2 (SARS-COV-2)-infected patients and has been considered as a risk factor in severe coronavirus disease-2019 (COVID-19). Whereas zinc might affect SARS-COV-2 replication and cell entry, the link between zinc deficiency and COVID-19 severity could also be attributed to the effects of COVID-19 on the body metabolism and immune response. Zinc deficiency is more prevalent in the elderly and patients with underlying chronic diseases, with established deleterious consequences such as the increased risk of respiratory infection. We reviewed the expected effects of zinc deficiency on COVID-19-related pathophysiological mechanisms focusing on both the renin-angiotensin and kinin-kallikrein systems. Mechanisms and effects were extrapolated from the available scientific literature. Zinc deficiency alters angiotensin-converting enzyme-2 (ACE2) function, leading to the accumulation of angiotensin II, des-Arg9-bradykinin and Lys-des-Arg9-bradykinin, which results in an exaggerated pro-inflammatory response, vasoconstriction and pro-thrombotic effects. Additionally, zinc deficiency blocks the activation of the plasma contact system, a protease cascade initiated by factor VII activation. Suggested mechanisms include the inhibition of Factor XII activation and limitation of high-molecular-weight kininogen, prekallikrein and Factor XII to bind to endothelial cells. The subsequent accumulation of Factor XII and deficiency in bradykinin are responsible for increased production of inflammatory mediators and marked hypercoagulability, as typically observed in COVID-19 patients. To conclude, zinc deficiency may affect both the renin-angiotensin and kinin-kallikrein systems, leading to the exaggerated inflammatory manifestations characteristic of severe COVID-19.