Fibrinolytic or anti-plasmin (nafamostat) therapy for COVID-19: A timing challenge for clinicians.
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ABSTRACT:
SUBMITTER: Ji HL
PROVIDER: S-EPMC8276553 | biostudies-literature | 2021 Oct
REPOSITORIES: biostudies-literature
Publications
Fibrinolytic or anti-plasmin (nafamostat) therapy for COVID-19: A timing challenge for clinicians.
Ji Hong-Long HL Wagener Brant M BM Ness Timothy J TJ Zhao Runzhen R
Pulmonary pharmacology & therapeutics 20210713
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Project description:A high rate of thrombotic complications, such as pulmonary embolism, has been linked to mortality in COVID-19, and appropriate treatment of thrombosis is important for lifesaving. Although heparin is frequently used to treat thrombotic pathology in COVID-19, pulmonary embolism is still seen in severe cases. Although systemic fibrinolytic therapy is a focus of attention because a thrombotic pathology is the cause of death in severe COVID-19, it should be kept in mind that fibrinolytic therapy might be harmful at advanced stage of COVID-19 where the status of disseminated intravascular coagulation (DIC) has been transmitted from suppressed-fibrinolytic to enhanced-fibrinolytic in disease progression of COVID-19. In this respect, inhalation therapy with fibrinolytic substances might be a safe and promising treatment.
| S-EPMC7499019 | biostudies-literature
Project description:BackgroundFibrin-rich clot formation in thrombo-occlusive pathologies is currently treated by systemic administration of plasminogen activators (e.g. tPA), to convert fibrin-associated plasminogen to plasmin for fibrinolytic action. However, this conversion is not restricted to clot site only but also occurs on circulating plasminogen, causing systemic fibrinogenolysis and bleeding risks. To address this, past research has explored tPA delivery using clot-targeted nanoparticles.ObjectivesWe designed a nanomedicine system that can (1) target clots via binding to activated platelets and fibrin, (2) package plasmin instead of tPA as a direct fibrinolytic agent, and (3) release this plasmin triggered by thrombin for clot-localized action.MethodsClot-targeted thrombin-cleavable nanoparticles (CTNPs) were manufactured using self-assembly of peptide-lipid conjugates. Plasmin loading and its thrombin-triggered release from CTNPs were characterized by UV-visible spectroscopy. CTNP-targeting to clots under flow was studied using microfluidics. Fibrinolytic effect of CTNP-delivered plasmin was studied in vitro using BioFlux imaging and D-dimer analysis and in vivo in a zebrafish thrombosis model.ResultsPlasmin-loaded CTNPs significantly bound to clots under shear flow and showed thrombin-triggered enhanced release of plasmin. BioFlux studies confirmed that thrombin-triggered plasmin released from CTNPs rendered fibrinolysis similar to free plasmin, further corroborated by D-dimer analysis. In the zebrafish model, CTNP-delivered plasmin accelerated time-to-recanalization, or completely prevented occlusion when infused before thrombus formation.ConclusionConsidering that the very short circulation half-life (<1 second) of plasmin prevents its systemic use but also makes it safer without off-target drug effects, clot-targeted delivery of plasmin using CTNPs can enable safer and more efficacious fibrinolytic therapy.
| S-EPMC10148984 | biostudies-literature
Project description:Fibrinolysis and pericellular proteolysis depend on molecular coassembly of plasminogen and its activator on cell, fibrin, or matrix surfaces. We report here the existence of a fibrinolytic cross-talk mechanism bypassing the requirement for their molecular coassembly on the same surface. First, we demonstrate that, despite impaired binding of Glu-plasminogen to the cell membrane by epsilon-aminocaproic acid (epsilon-ACA) or by a lysine-binding site-specific mAb, plasmin is unexpectedly formed by cell-associated urokinase (uPA). Second, we show that Glu-plasminogen bound to carboxy-terminal lysine residues in platelets, fibrin, or extracellular matrix components (fibronectin, laminin) is transformed into plasmin by uPA expressed on monocytes or endothelial cell-derived microparticles but not by tissue-type plasminogen activator (tPA) expressed on neurons. A 2-fold increase in plasmin formation was observed over activation on the same surface. Altogether, these data indicate that cellular uPA but not tPA expressed by distinct cells is specifically involved in the recognition of conformational changes and activation of Glu-plasminogen bound to other biologic surfaces via a lysine-dependent mechanism. This uPA-driven cross-talk mechanism generates plasmin in situ with a high efficiency, thus highlighting its potential physiologic relevance in fibrinolysis and matrix proteolysis induced by inflammatory cells or cell-derived microparticles.
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Project description: Not available
| S-EPMC8012272 | biostudies-literature
Project description:The COVID-19 pandemic has provided many challenges in the field of thrombosis and hemostasis. Among these is a novel form of coagulopathy that includes exceptionally high levels of D-dimer. D-dimer is a marker of poor prognosis, but does this also imply a causal relationship? These spectacularly raised D-dimer levels may actually signify the failing attempt of the fibrinolytic system to remove fibrin and necrotic tissue from the lung parenchyma, being consumed or overwhelmed in the process. Indeed, recent studies suggest that increasing fibrinolytic activity might offer hope for patients with critical disease and severe respiratory failure. However, the fibrinolytic system can also be harnessed by coronavirus to promote infectivity and where antifibrinolytic measures would also seem appropriate. Hence, there is a clinical paradox where plasmin formation can be either deleterious or beneficial in COVID-19, but not at the same time. Hence, it all comes down to timing.
| S-EPMC7323332 | biostudies-literature
Project description:The coronavirus disease 2019 (COVID-19) pandemic has caused respiratory failure and associated mortality in numbers that have overwhelmed global health systems. Thrombotic coagulopathy is present in nearly three quarters of patients with COVID-19 admitted to the intensive care unit, and both the clinical picture and pathologic findings are consistent with microvascular occlusive phenomena being a major contributor to their unique form of respiratory failure. Numerous studies are ongoing focusing on anticytokine therapies, antibiotics, and antiviral agents, but none to date have focused on treating the underlying thrombotic coagulopathy in an effort to improve respiratory failure in COVID-19. There are animal data and a previous human trial demonstrating a survival advantage with fibrinolytic therapy to treat acute respiratory distress syndrome. Here, we review the extant and emerging literature on the relationship between thrombotic coagulopathy and pulmonary failure in the context of COVID-19 and present the scientific rationale for consideration of targeting the coagulation and fibrinolytic systems to improve pulmonary function in these patients.
| S-EPMC7267116 | biostudies-literature
Project description:No effective treatment for COVID-19 has been well established yet. Nafamostat, known as anticoagulant, has potential anti-inflammatory and anti-viral activities against COVID-19. We report three cases of COVID-19 pneumonia who progressed while using antiviral drugs and needed supplementary oxygen therapy, improved after treatment with nafamostat. These preliminary findings show the possibility that Nafamostat can be considered to be used in elderly patients with COVID-19 pneumonia who need oxygen therapy. The effectiveness of nafamostat should be evaluated in further studies.
| S-EPMC7250091 | biostudies-literature
Project description:Two series of macrocyclic inhibitors addressing the S1 pocket and the prime site of the fibrinolytic serine protease plasmin have been developed. In the first series, a P1 tranexamoyl residue was coupled to 4-aminophenylalanine in P1' position, which provided moderately potent inhibitors with inhibition constants around 1 μM. In the second series, a substituted biphenylalanine was incorporated as P1' residue leading to approximately 1000-fold stronger plasmin inhibitors, the best compounds possess subnanomolar inhibition constants. The most effective compounds already exhibit a certain selectivity as plasmin inhibitors compared to other trypsin-like serine proteases such as trypsin, plasma kallikrein, thrombin, activated protein Ca, as well as factors XIa and Xa. For inhibitor 28 of the second series, the co-crystal structure in complex with a Ser195Ala microplasmin mutant revealed that the P2' residue adopts multiple conformations. Most polar contacts to plasmin and surrounding water molecules are mediated through the P1 tranexamoyl residue, whereas the bound conformation of the macrocycle is mainly stabilized by two intramolecular hydrogen bonds.
| S-EPMC11617653 | biostudies-literature
Project description:IntroductionIn COVID-19-related acute respiratory distress syndrome (ARDS), the clot play a role in gas exchange abnormalities. Fibrinolytic therapy can improve alveolar ventilation by restoring blood flow. In this systematic review and meta-analysis protocol, we aim to assess the safety and efficacy of fibrinolytic therapy in such a population.MethodsWe will perform a systematic search in MEDLINE, EMBASE, Cochrane CENTRAL and LILACS databases without language restrictions for relevant randomised controlled trials (RCTs) and quasi-RCTs. Two review authors will independently perform data extraction and quality assessments of data from included studies. In case of divergence, a third author will be contacted. The Cochrane handbook will be used for guidance. If the results are not appropriate for a meta-analysis, a descriptive analysis will be performed.DiscussionThis systematic review and meta-analysis protocol will provide current evidence about the safety and efficacy of fibrinolytic therapy in patients with COVID-19 and ARDS. These findings will provide if fibrinolytic therapy might be an option for a desperate clinical setting, where all medical efforts have been used.Prospero registration numberPROSPERO CRD42020187482.Ethics and disseminationEthics committee approval is not necessary. We intend to update the public registry, report any protocol amendments and publish the results in a widely accessible journal.
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Project description:The year 2020 witnessed a heavy death toll due to COVID-19, calling for a global emergency. The continuous ongoing research and clinical trials paved the way for vaccines. But, the vaccine efficacy in the long run is still questionable due to the mutating coronavirus, which makes drug re-positioning a reasonable alternative. COVID-19 has hence fast-paced drug re-positioning for the treatment of COVID-19 and its symptoms. This work builds computational models using matrix completion techniques to predict drug-virus association for drug re-positioning. The aim is to assist clinicians with a tool for selecting prospective antiviral treatments. Since the virus is known to mutate fast, the tool is likely to help clinicians in selecting the right set of antivirals for the mutated isolate. The main contribution of this work is a manually curated database publicly shared, comprising of existing associations between viruses and their corresponding antivirals. The database gathers similarity information using the chemical structure of drugs and the genomic structure of viruses. Along with this database, we make available a set of state-of-the-art computational drug re-positioning tools based on matrix completion. The tools are first analysed on a standard set of experimental protocols for drug target interactions. The best performing ones are applied for the task of re-positioning antivirals for COVID-19. These tools select six drugs out of which four are currently under various stages of trial, namely Remdesivir (as a cure), Ribavarin (in combination with others for cure), Umifenovir (as a prophylactic and cure) and Sofosbuvir (as a cure). Another unanimous prediction is Tenofovir alafenamide, which is a novel Tenofovir prodrug developed in order to improve renal safety when compared to its original counterpart (older version) Tenofovir disoproxil. Both are under trail, the former as a cure and the latter as a prophylactic. These results establish that the computational methods are in sync with the state-of-practice. We also demonstrate how the drugs to be used against the virus would vary as SARS-Cov-2 mutates over time by predicting the drugs for the mutated strains, suggesting the importance of such a tool in drug prediction. We believe this work would open up possibilities for applying machine learning models to clinical research for drug-virus association prediction and other similar biological problems.
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