Safety assessment and pharmacodynamics of a novel ultra low molecular weight heparin (RO-14) in healthy volunteers--a first-time-in-human single ascending dose study

Anticoagulation Management during Extracorporeal Membrane Oxygenation-A Mini-Review

Extracorporeal membrane oxygenation (ECMO) has been established as a life-saving technique for patients with the most severe forms of respiratory or cardiac failure. It can, however, be associated with severe complications. Anticoagulation therapy is required to prevent ECMO circuit thrombosis. It is, however, associated with an increased risk of hemocoagulation disorders. Thus, safe anticoagulation is a cornerstone of ECMO therapy. The most frequently used anticoagulant is unfractionated heparin, which can, however, cause significant adverse effects. Novel drugs (e.g., argatroban and bivalirudin) may be superior to heparin in the better predictability of their effects, functioning independently of antithrombin, inhibiting thrombin bound to fibrin, and eliminating heparin-induced thrombocytopenia. It is also necessary to keep in mind that hemocoagulation tests are not specific, and their results, used for setting up the dosage, can be biased by many factors. The knowledge of the advantages and disadvantages of particular drugs, limitations of particular tests, and individualization are cornerstones of prevention against critical events, such as life-threatening bleeding or acute oxygenator failure followed by life-threatening hypoxemia and hemodynamic deterioration. This paper describes the effects of anticoagulant drugs used in ECMO and their monitoring, highlighting specific conditions and factors that might influence coagulation and anticoagulation measurements.

The Auxiliary Role of Heparin in Bone Regeneration and its Application in Bone Substitute Materials

Bone regeneration in large segmental defects depends on the action of osteoblasts and the ingrowth of new blood vessels. Therefore, it is important to promote the release of osteogenic/angiogenic growth factors. Since the discovery of heparin, its anticoagulant, anti-inflammatory, and anticancer functions have been extensively studied for over a century. Although the application of heparin is widely used in the orthopedic field, its auxiliary effect on bone regeneration is yet to be unveiled. Specifically, approximately one-third of the transforming growth factor (TGF) superfamily is bound to heparin and heparan sulfate, among which TGF-β1, TGF-β2, and bone morphogenetic protein (BMP) are the most common growth factors used. In addition, heparin can also improve the delivery and retention of BMP-2 in vivo promoting the healing of large bone defects at hyper physiological doses. In blood vessel formation, heparin still plays an integral part of fracture healing by cooperating with the platelet-derived growth factor (PDGF). Importantly, since heparin binds to growth factors and release components in nanomaterials, it can significantly facilitate the controlled release and retention of growth factors [such as fibroblast growth factor (FGF), BMP, and PDGF] in vivo. Consequently, the knowledge of scaffolds or delivery systems composed of heparin and different biomaterials (including organic, inorganic, metal, and natural polymers) is vital for material-guided bone regeneration research. This study systematically reviews the structural properties and auxiliary functions of heparin, with an emphasis on bone regeneration and its application in biomaterials under physiological conditions.

Pharmacological and clinical application of heparin progress: An essential drug for modern medicine

Heparin is the earliest and most widely used anticoagulant and antithrombotic drug that is still used in a variety of clinical indications. Since it was discovered in 1916, after more than a century of repeated exploration, heparin has not been replaced by other drugs, but a great progress has been made in its basic research and clinical application. Besides anticoagulant and antithrombotic effects, heparin also has antitumor, anti-inflammatory, antiviral, and other pharmacological activities. It is widely used clinically in cardiovascular and cerebrovascular diseases, lung diseases, kidney diseases, cancer, etc., as the first anticoagulant medicine in COVID-19 exerts anticoagulant, anti-inflammatory and antiviral effects. At the same time, however, it also leads to a lot of adverse reactions, such as bleeding, thrombocytopenia, elevated transaminase, allergic reactions, and others. This article comprehensively reviews the modern research progress of heparin compounds; discusses the structure, preparation, and adverse reactions of heparin; emphasizes the pharmacological activity and clinical application of heparin; reveals the possible mechanism of the therapeutic effect of heparin in related clinical applications; provides evidence support for the clinical application of heparin; and hints on the significance of exploring the wider application fields of heparin.

Oral administration of dermatan sulphate reduces venous thrombus formation in vivo: potential use as a formulation for venous thromboembolism

Dermatan sulphate (DS) is a sulphated polysaccharide that displays complexity in constituent sulphated disaccharides and interacts with proteins and signalling molecules to modulate numerous biological processes, including inhibition of the coagulation cascade and regulation of blood clotting and fibrinolysis. This study shows the antithrombotic and anticoagulant effects of DS prepared from bovine collagen waste liquor following oral and intravenous administrations in a deep vein thrombosis (DVT) rabbit model. In vitro, the prothrombin time, activated partial thromboplastin time, and thrombin citrated plasma clotting assays revealed that bovine DS had strong antithrombotic and anticoagulant effects comparable to low-molecular-weight heparin [Clexane^® (enoxaparin sodium)]. In a DVT rabbit model, animals received intravenous and oral administrations of bovine DS and Clexane^® providing further evidence that both agents had strong antithrombotic and anticoagulant effects by significantly reducing or preventing clot formation. Thromboelastography (TEG) assays revealed further that both bovine DS and Clexane^® substantially prolonged the clotting time of recalcified citrated whole blood, but only bovine DS could retain clot strength suggesting that bovine DS had less effect on platelet-fibrin interactions. In conclusion, this is the first report that oral administration of DS from bovine collagen waste liquor reduces experimental venous thrombus formation warranting further research into bovine DS as an oral antithrombotic therapeutic.

Evolution of heparin anticoagulants to ultra-low-molecular-weight heparins: a review of pharmacologic and clinical differences and applications in patients with cancer

The burden of venous thromboembolism (VTE) is high in patients with cancer, particularly those with metastatic disease and those receiving chemotherapy. The use of heparin and heparin derivatives should be considered for primary prevention of VTE in hospitalized patients with cancer and in patients undergoing cancer surgery. Preliminary evidence also suggests that heparins may have direct anticancer benefits owing to effects on tumor growth, angiogenesis, and metastasis. Despite the potential benefits of heparin-derived anticoagulants, many at-risk patients do not receive adequate thromboprophylaxis. The evolution of unfractionated heparin to low-molecular-weight and ultra-low-molecular-weight heparins has provided practitioners with alternatives for VTE prevention in cancer, although these alternatives present challenges related to clinically relevant pharmacologic differences between agents. In this review, we present results from our review of the medical literature focusing on the use of the heparin-derived anticoagulants in prospective interventional studies of primary thromboprophylaxis in patients with cancer in surgical, hospitalized, and ambulatory settings.

Newer anticoagulants in 2009

Several newer anticoagulants are under clinical development. Recently two of them, Dabigatran etexilate/Pradaxa. and Rivaroxaban/Xarelto obtained marketing authorization in Europe and Canada for the prevention of thromboembolic events following major orthopedic surgery such as total hip and knee replacement. The results of Phase III clinical studies in thromboprophylaxis in major orthopedic surgery are highlighted and discussed in detail. Ongoing Phase II and III clinical trials assess their efficacy in the secondary prevention and treatment of deep vein thrombosis and pulmonary embolism, and in the long-term prevention of stroke in patients with non-valvular atrial fibrillation and in combination with aspirin and clopidogrel in patients with acute coronary syndromes. Many other small antithrombotic molecules including a new generation of low molecular weight heparins, are currently in different stages of clinical development. In addition to being administered orally, the newer anticoagulant agents have a more balanced benefit/risk ratio and wider therapeutic window. They have a rapid onset of action, a predictable anticoagulant effect that does not require routine laboratory monitoring. They have minor food and drug interactions, including those with cytochrome P450 and P.gp. They are highly specific and targeted to a single coagulation factor, and could carry similar or less hemorrhagic risks compared to the older anticoagulant agents. Finally, they may be used in a broader variety of patients, especially the medically ill patients with advanced cancer, and the elderly without any dosage adjustment, regardless of the patient age, gender, body weight, or in patients with mild renal impairment. Their use in the general world will hopefully confirm the promising results of clinical trials.