Is there a role for tissue plasminogen activator as a novel treatment for refractory COVID-19 associated acute respiratory distress syndrome?

Lessons learned from the mechanisms of posttraumatic inflammation extrapolated to the inflammatory response in COVID-19: a review

Up to 20% of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) patients develop severe inflammatory complications with diffuse pulmonary inflammation, reflecting acute respiratory distress syndrome (ARDS). A similar clinical profile occurs in severe trauma cases. This review compares pathophysiological and therapeutic principles of severely injured trauma patients and severe coronavirus disease 2019 (COVID-19). The development of sequential organ failure in trauma parallels deterioration seen in severe COVID-19. Based on established pathophysiological models in the field of trauma, two complementary pathways of disease progression into severe COVID-19 have been identified. Furthermore, the transition from local contained disease into systemic and remote inflammation has been addressed. More specifically, the traumatology concept of sequential insults ('hits') resulting in immune dysregulation, is applied to COVID-19 disease progression modelling. Finally, similarities in post-insult humoral and cellular immune responses to severe trauma and severe COVID-19 are described. To minimize additional 'hits' to COVID-19 patients, we suggest postponing all elective surgery in endemic areas. Based on traumatology experience, we propose that immunoprotective protocols including lung protective ventilation, optimal thrombosis prophylaxis, secondary infection prevention and calculated antibiotic therapy are likely also beneficial in the treatment of SARS-CoV-2 infections. Finally, rising SARS-CoV-2 infection and mortality rates mandate exploration of out-of-the box treatment concepts, including experimental therapies designed for trauma care.

Harnessing inflammation resolving-based therapeutic agents to treat pulmonary viral infections: What can the future offer to COVID-19?

Inflammation is generally accepted as a component of the host defence system and a protective response in the context of infectious diseases. However, altered inflammatory responses can contribute to disease in infected individuals. Many endogenous mediators that drive the resolution of inflammation are now known. Overall, mediators of resolution tend to decrease inflammatory responses and provide normal or greater ability of the host to deal with infection. In the lung, it seems that pro‐resolution molecules, or strategies that promote their increase, tend to suppress inflammation and lung injury and facilitate control of bacterial or viral burden. Here, we argue that the demonstrated anti‐inflammatory, pro‐resolving, anti‐thrombogenic and anti‐microbial effects of such endogenous mediators of resolution may be useful in the treatment of the late stages of the disease in patients with COVID‐19.

COVID-19: hemostatic parameters and specifics of antithrombotic treatment

In this review changes of hemostatic parameters in patients with COVID19 and their practical value are discussed. Current approaches to prevention and treatment of thrombotic/thromboembolic complications in patients with COVID-19 are considered.

Fibrinolytic abnormalities in acute respiratory distress syndrome (ARDS) and versatility of thrombolytic drugs to treat COVID-19

The global pandemic of coronavirus disease 2019 (COVID-19) is associated with the development of acute respiratory distress syndrome (ARDS), which requires ventilation in critically ill patients. The pathophysiology of ARDS results from acute inflammation within the alveolar space and prevention of normal gas exchange. The increase in proinflammatory cytokines within the lung leads to recruitment of leukocytes, further propagating the local inflammatory response. A consistent finding in ARDS is the deposition of fibrin in the air spaces and lung parenchyma. COVID-19 patients show elevated D-dimers and fibrinogen. Fibrin deposits are found in the lungs of patients due to the dysregulation of the coagulation and fibrinolytic systems. Tissue factor (TF) is exposed on damaged alveolar endothelial cells and on the surface of leukocytes promoting fibrin deposition, while significantly elevated levels of plasminogen activator inhibitor 1 (PAI-1) from lung epithelium and endothelial cells create a hypofibrinolytic state. Prophylaxis treatment of COVID-19 patients with low molecular weight heparin (LMWH) is important to limit coagulopathy. However, to degrade pre-existing fibrin in the lung it is essential to promote local fibrinolysis. In this review, we discuss the repurposing of fibrinolytic drugs, namely tissue-type plasminogen activator (tPA), to treat COVID-19 associated ARDS. tPA is an approved intravenous thrombolytic treatment, and the nebulizer form has been shown to be effective in plastic bronchitis and is currently in Phase II clinical trial. Nebulizer plasminogen activators may provide a targeted approach in COVID-19 patients to degrade fibrin and improving oxygenation in critically ill patients.

Pharmacological Agents Targeting Thromboinflammation in COVID-19: Review and Implications for Future Research

Coronavirus disease 2019 (COVID-19), currently a worldwide pandemic, is a viral illness caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The suspected contribution of thrombotic events to morbidity and mortality in COVID-19 patients has prompted a search for novel potential options for preventing COVID-19-associated thrombotic disease. In this article by the Global COVID-19 Thrombosis Collaborative Group, we describe novel dosing approaches for commonly used antithrombotic agents (especially heparin-based regimens) and the potential use of less widely used antithrombotic drugs in the absence of confirmed thrombosis. Although these therapies may have direct antithrombotic effects, other mechanisms of action, including anti-inflammatory or antiviral effects, have been postulated. Based on survey results from this group of authors, we suggest research priorities for specific agents and subgroups of patients with COVID-19. Further, we review other agents, including immunomodulators, that may have antithrombotic properties. It is our hope that the present document will encourage and stimulate future prospective studies and randomized trials to study the safety, efficacy, and optimal use of these agents for prevention or management of thrombosis in COVID-19.

[Drug treatment of coronavirus disease COVID-19: evidence exists?]

The article provides a review of foreign literature for 2020 on existing methods of drug treatment of coronavirus disease COVID-19. To date, in the treatment of COVID-19 in different countries, a little more than 10 drugs are used. The largest number of studies on the testing of these drugs is carried out by scientists from China, the USA, and European countries. It should be noted that among these drugs there is not a single new drug developed specifically for the treatment of COVID-19, the recommended and used drugs have previously been used to treat, as a rule, diseases of the viral etiology, less often another pathology. These suggestions are often based on analogy, the hypothesis of their supposed effectiveness for COVID-19. It can be assumed that a brake on the development of a drug specific for coronavirus disease is a poor knowledge of the pathogenesis of virus invasion in the body's adhesives and the development of complications. The review provides detailed literature data on drugs such as hydroxychloroquine / chloroquine, lopinavir/natinavir, remdesivir, ACE inhibitors and angiotensin converting enzyme receptor blockers, tissue plasminogen activator, as well as plasma transfusion transfusions.

COVID-19: The Potential Treatment of Pulmonary Fibrosis Associated with SARS-CoV-2 Infection

In December 2019, a novel coronavirus, SARS-CoV-2, appeared, causing a wide range of symptoms, mainly respiratory infection. In March 2020, the World Health Organization (WHO) declared Coronavirus Disease 2019 (COVID-19) a pandemic, therefore the efforts of scientists around the world are focused on finding the right treatment and vaccine for the novel disease. COVID-19 has spread rapidly over several months, affecting patients across all age groups and geographic areas. The disease has a diverse course; patients may range from asymptomatic to those with respiratory failure, complicated by acute respiratory distress syndrome (ARDS). One possible complication of pulmonary involvement in COVID-19 is pulmonary fibrosis, which leads to chronic breathing difficulties, long-term disability and affects patients' quality of life. There are no specific mechanisms that lead to this phenomenon in COVID-19, but some information arises from previous severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS) epidemics. The aim of this narrative review is to present the possible causes and pathophysiology of pulmonary fibrosis associated with COVID-19 based on the mechanisms of the immune response, to suggest possible ways of prevention and treatment.

Combination of thrombolytic and immunosuppressive therapy for coronavirus disease 2019: A case report

In a proportion of patients, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a multisystem syndrome characterized by hyperinflammation, acute respiratory distress syndrome (ARDS), and hypercoagulability. A 68-year-old man with coronavirus disease 2019 (COVID-19) was admitted to the intensive care unit with respiratory failure, cytokine release syndrome (CRS), and skin ischemia - microthrombosis. Specific coagulation and inflammatory markers (D-dimer, ferritin, and C-reactive protein), along with the clinical picture, triggered the trial of recombinant tissue plasminogen activator (rt-PA) and tocilizumab. This was followed by resolution of the skin ischemia and CRS, while respiratory parameters improved. No major complications associated with rt-PA or tocilizumab occurred. The combination of rt-PA with targeted anti-inflammatory treatment could be a new therapeutic option for patients with COVID-19, ARDS, hyperinflammation, and increased blood viscosity.

Fibrinolysis Shutdown Correlation with Thromboembolic Events in Severe COVID-19 Infection

Background

COVID-19 predisposes patients to a prothrombotic state with demonstrated microvascular involvement. The degree of hypercoagulability appears to correlate with outcomes; however, optimal criteria to assess for the highest-risk patients for thrombotic events remain unclear; we hypothesized that deranged thromboelastography measurements of coagulation would correlate with thromboembolic events.

Study Design

Patients admitted to an ICU with COVID-19 diagnoses who had thromboelastography analyses performed were studied. Conventional coagulation assays, d-dimer levels, and viscoelastic measurements were analyzed using a receiver operating characteristic curve to predict thromboembolic outcomes and new-onset renal failure.

Results

Forty-four patients with COVID-19 were included in the analysis. Derangements in coagulation laboratory values, including elevated d-dimer, fibrinogen, prothrombin time, and partial thromboplastin time, were confirmed; viscoelastic measurements showed an elevated maximum amplitude and low lysis of clot at 30 minutes. A complete lack of lysis of clot at 30 minutes was seen in 57% of patients and predicted venous thromboembolic events with an area under the receiver operating characteristic curve of 0.742 (p = 0.021). A d-dimer cutoff of 2,600 ng/mL predicted need for dialysis with an area under the receiver operating characteristic curve of 0.779 (p = 0.005). Overall, patients with no lysis of clot at 30 minutes and a d-dimer > 2,600 ng/mL had a venous thromboembolic event rate of 50% compared with 0% for patients with neither risk factor (p = 0.008), and had a hemodialysis rate of 80% compared with 14% (p = 0.004).

Conclusions

Fibrinolysis shutdown, as evidenced by elevated d-dimer and complete failure of clot lysis at 30 minutes on thromboelastography predicts thromboembolic events and need for hemodialysis in critically ill patients with COVID-19. Additional clinical trials are required to ascertain the need for early therapeutic anticoagulation or fibrinolytic therapy to address this state of fibrinolysis shutdown.

COVID-19 and Cancer: a Comprehensive Review

Purpose of Review

The outbreak of the novel coronavirus disease 2019 (COVID-19) has emerged to be the biggest global health threat worldwide, which has now infected over 1.7 million people and claimed more than 100,000 lives around the world. Under these unprecedented circumstances, there are no well-established guidelines for cancer patients.

Recent Findings

The risk for serious disease and death in COVID-19 cases increases with advancing age and presence of comorbid health conditions. Since the emergence of the first case in Wuhan, China, in December 2019, tremendous research efforts have been underway to understand the mechanisms of infectivity and transmissibility of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a fatal virus responsible for abysmal survival outcomes. To minimize the mortality rate, it becomes prudent to identify symptoms promptly and employ treatments appropriately. Even though no cure has been established, multiple clinical trials are underway to determine the most optimal strategy. Managing cancer patients under these circumstances is rather challenging, given their vulnerable status and the aggressive nature of their underlying disease.

Summary

In this comprehensive review, we discuss the impact of COVID-19 on health and the immune system of those affected, reviewing the latest treatment approaches and ongoing clinical trials. Additionally, we discuss challenges faced while treating cancer patients and propose potential approaches to manage this vulnerable population during this pandemic.

COVID-19 - Toward a comprehensive understanding of the disease

The evidence on the pathophysiology of the novel coronavirus SARS-CoV-2 infection is rapidly growing. Understanding why some patients suffering from COVID-19 are getting so sick, while others are not, has become an informal imperative for researchers and clinicians around the globe. The answer to this question would allow rationalizing the fear surrounding this pandemic. Understanding of the pathophysiology of COVID-19 relies on an understanding of interplaying mechanisms, including SARS-CoV-2 virulence, human immune response, and complex inflammatory reactions with coagulation playing a major role. An interplay with bacterial co-infections, as well as the vascular system and microcirculation affected throughout the body should also be examined. More importantly, a compre-hensive understanding of pathological mechanisms of COVID-19 will increase the efficacy of therapy and decrease mortality. Herewith, presented is the current state of knowledge on COVID-19: beginning from the virus, its transmission, and mechanisms of entry into the human body, through the pathological effects on the cellular level, up to immunological reaction, systemic and organ presentation. Last but not least, currently available and possible future therapeutic and diagnostic options are briefly commented on.

[The Agreed Experts' Position of the Eurasian Association of Therapists on Some new Mechanisms of COVID-19 Pathways: Focus on Hemostasis, Hemotransfusion Issues and Blood gas Exchange]

The article discusses pathogenesis and treatment of COVID-19. The authors presented state-of-the-art insight into hemostatic disorders in patients with COVID-19 and clinical recommendations on prevention of thrombosis and thromboembolism in patients infected with SARS-CoV-2. The article discussed in detail a new hypothesis proposed by Chinese physicians about a new component in the pathogenesis of COVID-19, namely, about the effect of SARS-CoV-2 virus on the hemoglobin beta-chain and the formation of a complex with porphyrin, which results in displacement of the iron ion. Thus, hemoglobin loses the capability for transporting oxygen, which aggravates hypoxia and worsens the prognosis. The article stated rules of hemotransfusion safety in the conditions of COVID-19 pandemic.

The contact activation system as a potential therapeutic target in patients with COVID-19

Coronavirus disease 2019 (COVID-19) is predicted to overwhelm health care capacity in the United States and worldwide, and, as such, interventions that could prevent clinical decompensation and respiratory compromise in infected patients are desperately needed. Excessive cytokine release and activation of coagulation appear to be key drivers of COVID-19 pneumonia and associated mortality. Contact activation has been linked to pathologic upregulation of both inflammatory mediators and coagulation, and accumulating preclinical and clinical data suggest it to be a rational therapeutic target in patients with COVID-19. Pharmacologic inhibition of the interaction between coagulation factors XI and XII has been shown to prevent consumptive coagulopathy, pathologic systemic inflammatory response, and mortality in at least 2 types of experimental sepsis. Importantly, inhibition of contact activation also prevented death from Staphylococcus aureus-induced lethal systemic inflammatory response syndrome in nonhuman primates. The contact system is likely dispensable for hemostasis and may not be needed for host immunity, suggesting it to be a reasonably safe target that will not result in immunosuppression or bleeding. As a few drugs targeting contact activation are already in clinical development, immediate clinical trials for their use in patients with COVID-19 are potentially feasible for the prevention or treatment of respiratory distress.

Salvage use of tissue plasminogen activator (tPA) in the setting of acute respiratory distress syndrome (ARDS) due to COVID-19 in the USA: a Markov decision analysis

Background

COVID-19 threatens to quickly overwhelm our existing critical care infrastructure in the USA. Systemic tissue plasminogen activator (tPA) has been previously demonstrated to improve PaO₂/FiO₂ (mmHg) when given to critically ill patients with acute respiratory distress syndrome (ARDS). It is unclear to what extent tPA may impact population-based survival during the current US COVID-19 pandemic.

Methods

A decision analytic Markov state transition model was created to simulate the life critically ill COVID-19 patients as they transitioned to either recovery or death. Two patient groups were simulated (50,000 patients in each group); (1) Patients received tPA immediately upon diagnosis of ARDS and (2) patients received standard therapy for ARDS. Base case critically ill COVID-19 patients were defined as having a refractory PaO₂/FiO₂ of < 60 mmHg (salvage use criteria). Transition from severe to moderate to mild ARDS, recovery, and death were estimated. Markov model parameters were extracted from existing ARDS/COVID-19 literature.

Results

The use of tPA was associated with reduced mortality (47.6% [tTPA] vs. 71.0% [no tPA]) for base case patients. When extrapolated to the projected COVID-19 eligible for salvage use tPA in the USA, peak mortality (deaths/100,000 patients) was reduced for both optimal social distancing (70.5 [tPA] vs. 75.0 [no tPA]) and no social distancing (158.7 [tPA] vs. 168.8 [no tPA]) scenarios.

Conclusions

Salvage use of tPA may improve recovery of ARDS patients, thereby reducing COVID-19-related mortality and ensuring sufficient resources to manage this pandemic.