1000/1000
Hot
Most Recent
Seaweed sulfated polysaccharides (PSs) has wide therapeutic potential, 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.
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. In the initial stage of the disease, a significant number of COVID-19 patients develop signs of hypercoagulation, and in the later stages, signs of disseminated intravascular coagulation (DIC) syndrome. Coagulation disorders and their clinical manifestations have a number of differences from the classic DIC syndrome, and are named COVID-associated coagulopathy [1][2][3].
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 [1][4][5][6].
The treatment of COVID-19 patients and, in particular, correction of the hemostasis disorders is a difficult problem. Despite the data on the effectiveness of heparin drugs in reducing mortality in severe COVID-19 patients, and despite thromboprophylaxis [7][8], the development of venous and arterial thromboembolic complications has been reported. There is also a problem with the optimal dosage of anticoagulant agent [5][9][10][11]. Thus, there are a number of unresolved issues regarding the use of these drugs.
In this regard, there is a need to use the effective anticoagulants and antithrombotic drugs, as well as their optimal dosages, in the treatment of COVID-19 patients and for the prevention of thrombotic complications [7][12][13].
Despite the success achieved in SARS-CoV-2 therapy, the development of more effective treatment regimens for this infection with the inclusion of anticoagulants, thrombolytics, and fibrinolytics, as well as the search for new effective drugs of this pharmacological group, does not lose relevance. The wide therapeutic potential of seaweed sulfated polysaccharides (PSs), including anticoagulant, thrombolytic, and fibrinolytic activities, opens up a new possibilities for their study in experimental and clinical trials.
There is also the problem of anticoagulants’ optimal dose strategy. For example, a reduction in mortality in hospitalized patients with COVID-19 is shown when using a therapeutic, but not a preventive, dose of anticoagulants [12][13][36].
Taking into account the high frequency of thromboembolic complications, the International Society on Thrombosis and Haemostasis’ guidelines continue to recommend thromboprophylaxis for all hospitalized patients, and in most patients with COVID-19, thromboprophylaxis should be continued after hospital discharge [9].
The Expert Group of American Society of Hematology recommended the use of prophylactic-intensity anticoagulation compared to moderate-intensity or therapeutic-intensity anticoagulants for critical COVID-19-related patients or acute COVID-19 patients who do not have a confirmed VTE [37]. Taking into consideration their activation and their role in the clot formations, platelets are a potential target for the prevention of complications in SARS-CoV-2 infection [38][39][40][41]. The most commonly used antiplatelet agents are aspirin, clopidogrel, lopinavir/ritonavir, vorapaxar, and dipyridamole [41][42][43][44]. Among the antiplatelet agents, aspirin and clopidogrel are associated with decreased risk of ARDS, as well as decreased mortality among critically ill COVID-19 patients [43][44].
Vorapaxar and dipyridamole are considered promising antiplatelet agents for the treatment of COVID-19. Vorapaxar exhibits its antiplatelet activity through the antagonism of protease-activated receptor 1 (PAR-1), which plays an important role in thrombin-induced platelet aggregation, and is associated with blood clotting and inflammation [45].
For example, Liu et al. [42] used dipyridamole with a positive clinical effect. However, these authors note that there are a number of questions regarding the use of antiplatelet drugs in COVID-19 treatment, and therefore additional clinical trials are needed [42].
The data presented above indicate that anticoagulant and antithrombotic therapy play a key role in the treatment of hemostasis disorders in COVID-19, but there are still a number of unresolved issues regarding the use of these drugs. Thus, the optimal effective anticoagulant and antithrombotic agents, as well as their doses, remain uncertain.
A separate problem is the interaction of antithrombotic and anticoagulant drugs with specific drugs in COVID-19 treatments, since not all drugs are compatible. An individual approach to the patient is recommended, aimed at the optimal risk/benefit ratio of various antithrombotic strategies, taking into account the underlying hypercoagulable state.
Therefore, the treatment of patients and prevention of thrombosis in COVID-19 requires solving issues related to the need to find new effective anticoagulants, as well as their optimal dosage. In this regard, the search for new effective anticoagulants remains relevant. In this aspect, the sulfated PSs of seaweed are of interest.
Seaweed sulfated polysaccharides (PS) possess anticoagulant, antithrombotic, and fibrinolytic properties. These activities depends on the structural features (content and position of sulfate groups on the main chain of the PSs, molecular weight, monosaccharide composition and type of glycosidic bonds, the degree of PS chain branching, etc.). Sulfated PSs act on the hemostasis system both directly and indirectly and affect the factors of the extrinsic and intrinsic coagulation pathways, as well as the final stage of coagulation or the conversion of fibrinogen to fibrin under the thrombin influence. Anticoagulant activity of PS can be associated with plasma AT III, and antithrombotic activity—with an increase in the level of t-PA and competitive binding to the t-PA-PAI-1 complex.
The combination of the anticoagulant, antithrombotic, and fibrinolytic properties allows us to consider seaweed sulfated PSs as alternative sources of new anticoagulant and antithrombotic compounds. In this regard, and along with the low toxicity and relative low cost of their production, sulfated PSs are promising for clinical use and represent an alternative to heparin. The wide therapeutic potential of seaweed sulfated 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 in the fight against coronaviruses due to their natural origin, safety, and low cost compared to synthetic drugs. However, further investigations are needed regarding the use of seaweed PSs as potential anticoagulants, thrombolytics, and fibrinolytics aimed to correct hemostasis disorders in COVID-19 patients.