Three structurally different fucoidans from the brown seaweeds Saccharina latissima (SL), Fucus vesiculosus (FV), and Cladosiphon okamuranus (CO), two chemically modified fucoidans with a higher degree of sulfation (SL-S, CO-S), and a synthetic totally sulfated octasaccharide (OS), related to fucoidans, were assessed on anticoagulant and antithrombotic activities in different in vitro experiments. The effects were shown to depend on the structural features of the compounds tested. Native fucoidan SL with a degree of sulfation (DS) of 1.3 was found to be the most active sample, fucoidan FV (DS 0.9) demonstrated moderate activity, while the polysaccharide CO (DS 0.4) was inactive in all performed experiments, even at high concentrations. Additional introduction of sulfate groups into fucoidan SL slightly decreased the anticoagulant effect of SL-S, while sulfation of CO, giving rise to the preparation CO-S, increased the activity dramatically. The high level of anticoagulant activity of polysaccharides SL, SL-S, and CO-S was explained by their ability to form ternary complexes with ATIII-Xa and ATIII-IIa, as well as to bind directly to thrombin. Synthetic per-O-sulfated octasaccharide OS showed moderate anticoagulant effect, determined mainly by the interaction of OS with the factor Xa in the presence of ATIII. Comparable tendencies were observed in the antithrombotic properties of the compounds tested.

BackgroundIn experimental systems, interference with coagulation can affect tumor biology. We suggested that abnormal coagulation could be a negative predictor for response to immunotherapy and survival among patients with metastatic renal cell carcinoma (MRCC).MethodsTo address this issue, retrospective analysis of 289 previously untreated MRCC patients entering on institutional review board-approved clinical trials was conducted between 2003 and 2006. In addition, two groups of MRCC patients with (n = 28) or without (n = 28) hypercoagulability were compared in a case-control study. Baseline and treatment characteristics were well balanced.ResultsHypercoagulability was present at treatment start in 40% of patients. Median baseline fibrinogen was 6.2 mg/dl. Serious disorders were found in 68% of patients. Abnormal coagulation was strongly associated with a number of metastatic sites (2 and more metastatic sites vs. 0–1 (P = .001). Patients with high extent of hypercoagulability had significantly higher number of metastatic sites (P = .02). On univariate analysis, patients with hypercoagulability had significantly shorter overall survival than patients with normal coagulation; median survivals of 8.9 and 16.3, respectively (P = .001).Short survival and low response rate also were significantly associated with hypercoagulability in a case-control study. Median survival was 8.2 months and 14.6 months, respectively (P = .0011). Disease control rate (overall response + stable disease) was significantly higher in patients with normal coagulation: 71.4 versus 42.9% (P = .003).ConclusionHypercoagulability disorders were found to be prognostic factor for response rate to systemic therapy and survival in patients with MRCC.

In recent decades, significant progress has been made in understanding the mechanisms of platelet function and platelet hemostasis correction. Platelets are considered as the most important participants of both normal, and pathological thrombotic process characteristic of the most different diseases and states. In the present review pathophysiological mechanisms of platelet synthesis of various mediators with paracrine effects, which can influence the function of other cells, are consecrated. The physiology of platelets was considered in detail. The leading role of platelets in pathogenesis of the majority of diseases of cardiovascular system as modulators of inflammatory reactions of the immune response which are considered as the leading mechanism of development of atherosclerosis was shown. The ability of platelets to encode inflammatory proteins allowing them to influence adaptive immunity functions was discussed. The role of platelets as a key component of the innate immune system was presented, which is confirmed by the presence of Tolllike receptors (TLR) and glycoproteins, such as integrin αIIbβ3, glycoprotein Ib-IX and FcγRIIa, involved in interaction with bacterial cells. The pathogenesis of the formation of platelet-leukocyte aggregates due to the rapid reversible interaction of P-selectin (CD62P) on the platelet surface with ligand-1 glycoprotein P-selectin (PSGL-1) on the plasma of leukocytes and the mechanism of extracellular neutrophil traps (NETs), as well as the influence of platelets on the function of lymphocytes was presented. The role of platelets in cancer progression, metastasis and thrombosis is considered, and the interrelation of thrombosis and metastasis in malignant diseases was analyzed. The efficiency of the use of antithrombotic drugs in the prevention of thrombosis and, as a consequence, in the prevention of cardiovascular diseases and cancer was discussed.

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15591 Background: Antitumor effects of LMWH are unclear. Heparin can bind with fibroblast-growth factor, other heparine-binding angiogenic factors, their receptors, and/or impact on coagulation system which induces angiogenesis. We previously revealed hypercoagulation is a frequent symptom in metastatic renal cell carcinoma (MRCC) patients (pts) and clinically correlates with progression of the disease. Methods: Pts with MRCC and high level of fibrinogen, D-dimer or fibrin, antithrombin III and prothrombin were stratified by MSKCC prognostic criteria and included to receive immunotherapy plus LMWH (IL-2, 1 MIU, i.v, 3 tiw + IFN alpha, 5 MU, s.c, 3 tiw ± 5-FU 500 mg/m2, i.v. once a week, and Dalteparin, LMWH, 5000 IU, s.c, every day, for 3 weeks) or immunotherapy alone. Demographic and treatment characteristics were similar between both arms. The primary endpoint was cancer-related overall survival (OS). Results: Flu-like syndrome, hypotension, anorexia were most common side effects (CTC grade 1). There were no bleedings in LMWH group. Conclusions: These results demonstrate that Dalteparin significantly improves cancer specific overall survival and decreases disease progression rate in combination with immunotherapy in MRCC pts with abnormal coagulation. Phase II randomized multicenter open-label discontinuation trial will be conducted. [Table: see text] No significant financial relationships to disclose.

The purpose of the review is to highlight the current possibilities for the prevention and treatment of venous thrombotic complications in patients with cancer.The data of 52 scientific sources published in the Russian and foreign press in 1997–2020 are considered.Cancer patients are at high risk of thrombotic complications, which worsen the outcome of anticancer treatment and are one of the leading causes of death. Thrombosis in an oncological patient increases the risk of death by 30 times, which is associated with fatal thromboembolism and a more aggressive course of the disease. The leading role in the pathogenesis of thrombotic complications is played by disorders in the hemostasis system caused both by the tumor itself and by therapy. Low molecular weight heparins are considered the basis for specific prophylaxis of thromboembolic complications in cancer patients. The use of low molecular weight heparins after surgery and during chemotherapy effectively reduces the incidence of venous thrombosis. Direct oral anticoagulants are promising drugs for oral administration and are indicated as one of the treatment options for patients with tumor-associated thrombosis with a low risk of bleeding and no drug interactions with ongoing systemic chemotherapy.

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