The Potency of Seaweed Sulfated Polysaccharides for the Correction of Hemostasis Disorders in COVID-19.

Hemostasis disorders play an important role in the pathogenesis, clinical manifestations, and outcome of COVID-19. First of all, the hemostasis system suffers due to a complicated and severe course of COVID-19. A significant number of COVID-19 patients develop signs of hypercoagulability, thrombocytopenia, and hyperfibrinolysis. Patients with severe COVID-19 have a tendency toward thrombotic complications in the venous and arterial systems, which is the leading cause of death in this disease. Despite the success achieved in the treatment of SARS-CoV-2, the search for new effective anticoagulants, thrombolytics, and fibrinolytics, as well as their optimal dose strategies, continues to be relevant. The wide therapeutic potential of seaweed sulfated polysaccharides (PSs), including anticoagulant, thrombolytic, and fibrinolytic activities, opens up new possibilities for their study in experimental and clinical trials. These natural compounds can be important complementary drugs for the recovery from hemostasis disorders due to their natural origin, safety, and low cost compared to synthetic drugs. In this review, the authors analyze possible pathophysiological mechanisms involved in the hemostasis disorders observed in the pathological progression of COVID-19, and also focus the attention of researchers on seaweed PSs as potential drugs aimed to correction these disorders in COVID-19 patients. Modern literature data on the anticoagulant, antithrombotic, and fibrinolytic activities of seaweed PSs are presented, depending on their structural features (content and position of sulfate groups on the main chain of PSs, molecular weight, monosaccharide composition and type of glycosidic bonds, the degree of PS chain branching, etc.). The mechanisms of PS action on the hemostasis system and the issues of oral bioavailability of PSs, important for their clinical use as oral anticoagulant and antithrombotic agents, are considered. The combination of the anticoagulant, thrombolytic, and fibrinolytic properties, along with low toxicity and relative cheapness of production, open up prospects for the clinical use of PSs as alternative sources of new anticoagulant and antithrombotic compounds. However, further investigation and clinical trials are needed to confirm their efficacy.

Effects of Omega-3 Polyunsaturated Fatty Acids and Their Metabolites on Haemostasis-Current Perspectives in Cardiovascular Disease.

The beneficial effects of long-chain polyunsaturated omega-3 fatty acids (omega-3 PUFAs) in cardioprotection are widely known and generally accepted. In this literature review, we have focused on the known and postulated mechanisms of action of omega-3 PUFAs and their metabolites on various components of the haemostatic system, in particular on blood platelets and endothelium. We have also made an attempt to provide a comprehensive review of epidemiological studies with particular regard to clinical trials. Notably, the results of these studies are contradictory, and some of them failed to report the beneficial effects of taking or supplementing omega-3 PUFAs in the diet. A potential explanation, in our opinion, could be the need to use higher doses of omega-3 PUFAs and a proper ratio of omega-3 and omega-6 PUFAs. An additional problem which is difficult to solve is the use of a proper neutral placebo for interventional studies. Despite some controversies regarding the beneficial effects of supplementation of omega-3 PUFAs in cardiovascular disease, our review suggests that a promising aspect of future studies and applications is to focus on the anti-thrombotic properties of these compounds. An argument supporting this assumption is the recent use of omega-3 PUFAs as a supporting tool for the treatment of COVID-19 complications.

Therapeutic Potential of Resveratrol in COVID-19-Associated Hemostatic Disorders.

Coagulation disorders, endotheliopathy and inflammation are the most common hallmarks in SARS-CoV-2 infection, largely determining COVID-19's outcome and severity. Dysfunctions of endothelial cells and platelets are tightly linked in contributing to the systemic inflammatory response that appears to be both a cause and a consequence of COVID-19-associated coagulation disorders and thrombotic events. Indeed, elevated levels of circulating inflammatory cytokines are often associated with abnormal coagulation parameters in COVID-19 patients. Although treatments with low molecular weight heparin (LMWH) have shown beneficial effects in decreasing patient mortality with severe COVID-19, additional therapeutic strategies are urgently needed. Utilizing the anti-inflammatory and anti-thrombotic properties of natural compounds may provide alternative therapeutic approaches to prevent or reduce the risk factors associated with pre-existing conditions and comorbidities that can worsen COVID-19 patients' outcomes. In this regard, resveratrol, a natural compound found in several plants and fruits such as grapes, blueberries and cranberries, may represent a promising coadjuvant for the prevention and treatment of COVID-19. By virtue of its anti-thrombotic and anti-inflammatory properties, resveratrol would be expected to lower COVID-19-associated mortality, which is well known to be increased by thrombosis and inflammation. This review analyzes and discusses resveratrol's ability to modulate vascular hemostasis at different levels targeting both primary hemostasis (interfering with platelet activation and aggregation) and secondary hemostasis (modulating factors involved in coagulation cascade).

Modulation of endothelial organelle size as an antithrombotic strategy.

BACKGROUND: It is long established that von Willebrand factor (VWF) is central to hemostasis and thrombosis. Endothelial VWF is stored in cell-specific secretory granules, Weibel-Palade bodies (WPBs), organelles generated in a wide range of lengths (0.5-5.0 µm). WPB size responds to physiological cues and pharmacological treatment, and VWF secretion from shortened WPBs dramatically reduces platelet and plasma VWF adhesion to an endothelial surface. OBJECTIVE: We hypothesized that WPB-shortening represented a novel target for antithrombotic therapy. Our objective was to determine whether compounds exhibiting this activity do exist. METHODS: Using a microscopy approach coupled to automated image analysis, we measured the size of WPB bodies in primary human endothelial cells treated with licensed compounds for 24 hours. RESULTS AND CONCLUSIONS: A novel approach to identification of antithrombotic compounds generated a significant number of candidates with the ability to shorten WPBs. In vitro assays of two selected compounds confirm that they inhibit the pro-hemostatic activity of secreted VWF. This set of compounds acting at a very early stage of the hemostatic process could well prove to be a useful adjunct to current antithrombotic therapeutics. Further, in the current SARS-CoV-2 pandemic, with a considerable fraction of critically ill COVID-19 patients affected by hypercoagulability, these WPB size-reducing drugs might also provide welcome therapeutic leads for frontline clinicians and researchers.

Thrombosis and Haemostasis challenges in COVID-19 - Therapeutic perspectives of heparin and tissue-type plasminogen activator and potential toxicological reactions-a mini review.

The coronavirus disease (COVID)-19 pandemic is a major challenge for the health systems worldwide. Acute respiratory distress syndrome (ARDS), is one of the most common complications of the COVID-19 infection. The activation of the coagulation system plays an important role in the pathogenesis of ARDS. The development of lung coagulopathy involves thrombin generation and fibrinolysis inhibition. Unfractionated heparin and its recently introduced counterpart low molecular weight heparin (LMWH), are widely used anticoagulants with a variety of clinical indications allowing for limited and manageable physio-toxicologic side effects while the use of protamine sulfate, heparin's effective antidote, has made their use even safer. Tissue-type plasminogen activator (tPA) is approved as intravenous thrombolytic treatment. The present narrative review discusses the use of heparin and tPA in the treatment of COVID-19-induced ARDS and their related potential physio-toxicologic side effects. The article is a quick review of articles on anticoagulation in COVID infection and the potential toxicologic reactions associated with these drugs.

The haemostatic profile in critically ill COVID-19 patients receiving therapeutic anticoagulant therapy: An observational study.

Hypercoagulability and thrombosis remain a challenge in severe coronavirus disease 2019 (COVID-19) infections. Our aim is to investigate the hemostatic profile of critically ill COVID-19 patients on therapeutic anticoagulant treatment.Forty one patients were enrolled into the study. We recruited 11 consecutive, COVID-19, patients who received therapeutic anticoagulant treatment on intensive care unit (ICU) admission. Disease severity indexes, biochemical, hematological and haemostatic parameters, endogenous thrombin potential (ETP), plasminogen activator inhibitor-1 (PAI-1) activity and extrinsically activated rotational thromboelastometry assay (EXTEM) were recorded on days 1, 3, 7. We also enrolled 9 ICU non-COVID-19, 21 non-ICU COVID-19 patients and 20 healthy blood donors as control populations.Critically ill COVID-19 patients demonstrated a more hypercoagulable and hypofibrinolytic profile related to those with COVID-19 mild illness, based on EXTEM amplitude at 10 min (A10), maximum clot firmness (MCF) and lysis index at 60 min (LI60) variables (p = 0.020, 0.046 and 0.001, respectively). Similarly, a more hypercoagulable state was detected in COVID-19 ICU patients related to non-COVID-19 ICU patients based on A10 and MCF parameters (p = 0.03 and 0.04, respectively). On the contrary, ETP and EXTEM (clotting time) CT values were similar between patients with severe and mild form of the COVID-19 infection, probably due to anticoagulant treatment given.Critically ill COVID-19 patients showed a hypercoagulable profile despite the therapeutic anticoagulant doses given. Due to the small sample size and the study design, the prognostic role of the hypercoagulability in this clinical setting remains unknown and further research is required in order to be assessed.

[Management of the thrombotic risk associated with COVID-19: what is the role of the hemostasis laboratory?] / Apport du laboratoire d'hémostase dans la gestion du risque thrombotique associé au Covid-19.

COVID-19 is associated with disturbances of hemostasis in the laboratory and an increased thrombotic risk. Routine laboratory tests - activated partial thromboplastin time (aPTT), prothrombin time, Clauss fibrinogen and D-dimers levels measurement - are used for the evaluation of the thrombotic risk and the monitoring of hemostasis, but are subject to several drawbacks that may affect the reliability and clinical relevance of the delivered results. Another challenge for the hemostasis laboratory is the monitoring of heparin treatment. For instance, the issue of the monitoring of unfractionated heparin remains debated, the more so when there is a tremendous inflammatory response. This brief review considers the role of laboratory tests of hemostasis in the management of COVID-19 and discusses their main limitations to be kept in mind.