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Chest Feb 2012This article describes the pharmacology of approved parenteral anticoagulants. These include the indirect anticoagulants, unfractionated heparin (UFH),... (Comparative Study)
Comparative Study Review
This article describes the pharmacology of approved parenteral anticoagulants. These include the indirect anticoagulants, unfractionated heparin (UFH), low-molecular-weight heparins (LMWHs), fondaparinux, and danaparoid, as well as the direct thrombin inhibitors hirudin, bivalirudin, and argatroban. UFH is a heterogeneous mixture of glycosaminoglycans that bind to antithrombin via a unique pentasaccharide sequence and catalyze the inactivation of thrombin, factor Xa, and other clotting enzymes. Heparin also binds to cells and plasma proteins other than antithrombin causing unpredictable pharmacokinetic and pharmacodynamic properties and triggering nonhemorrhagic side effects, such as heparin-induced thrombocytopenia (HIT) and osteoporosis. LMWHs have greater inhibitory activity against factor Xa than thrombin and exhibit less binding to cells and plasma proteins than heparin. Consequently, LMWH preparations have more predictable pharmacokinetic and pharmacodynamic properties, have a longer half-life than heparin, and are associated with a lower risk of nonhemorrhagic side effects. LMWHs can be administered once daily or bid by subcutaneous injection, without coagulation monitoring. Based on their greater convenience, LMWHs have replaced UFH for many clinical indications. Fondaparinux, a synthetic pentasaccharide, catalyzes the inhibition of factor Xa, but not thrombin, in an antithrombin-dependent fashion. Fondaparinux binds only to antithrombin. Therefore, fondaparinux-associated HIT or osteoporosis is unlikely to occur. Fondaparinux exhibits complete bioavailability when administered subcutaneously, has a longer half-life than LMWHs, and is given once daily by subcutaneous injection in fixed doses, without coagulation monitoring. Three additional parenteral direct thrombin inhibitors and danaparoid are approved as alternatives to heparin in patients with HIT.
Topics: Antithrombins; Arginine; Chondroitin Sulfates; Dermatan Sulfate; Dose-Response Relationship, Drug; Evidence-Based Medicine; Fibrinolytic Agents; Fondaparinux; Heparin; Heparin, Low-Molecular-Weight; Heparitin Sulfate; Hirudins; Humans; Infusions, Intravenous; Peptide Fragments; Pipecolic Acids; Polysaccharides; Practice Guidelines as Topic; Recombinant Proteins; Societies, Medical; Sulfonamides; Thrombin; Thrombosis; United States
PubMed: 22315264
DOI: 10.1378/chest.11-2291 -
Journal of Thrombosis and Haemostasis :... Aug 2022Several leech species of the genera Hirudo, Hirudinaria, and Whitmania are widely used in traditional Chinese medicine (TCM) for the oral treatment of disorders...
BACKGROUND
Several leech species of the genera Hirudo, Hirudinaria, and Whitmania are widely used in traditional Chinese medicine (TCM) for the oral treatment of disorders associated with blood stasis. Among them, the non-hematophagous leech Whitmania pigra expresses a variety of components that have the potential to act on the vertebrate blood coagulation system.
OBJECTIVE
Whether the thrombin inhibitor hirudin, probably the most prominent leech-derived anticoagulant, is actually present in Whitmania pigra, is still a matter of debate. To answer that open question was the aim of the study.
METHODS
We identified several putative hirudin-encoding sequences in transcriptome data of Whitmania pigra. Upon gene synthesis and molecular cloning the respective recombinant proteins were expressed in Escherichia coli, purified, processed, and eventually functionally characterized for thrombin-inhibitory potencies in coagulation assays.
RESULTS
We were successful in the identification and functional characterization of several putative hirudins in Whitmania pigra. Some, but not all, of these factors are indeed thrombin inhibitors. Whitmania pigra hence expresses both hirudins (factors that inhibit thrombin) and hirudin-like factors (that do not or only very weakly inhibit thrombin). Furthermore, we revealed the exon/intron structures of the corresponding genes. Coding sequences of some putative hirudins of Whitmania pigra were present also in transcriptome datasets of Hirudo nipponia, a hematophagous leech that is likewise used in TCM.
CONCLUSIONS
Based on both structural and functional data we provide very strong evidence for the expression of hirudins in Whitmania pigra. This is the first description of hirudins in a non-hematophagous leech.
Topics: Amino Acid Sequence; Animals; Anticoagulants; Blood Coagulation; Hirudins; Leeches; Thrombin
PubMed: 35587545
DOI: 10.1111/jth.15762 -
Journal of Vascular Surgery Jul 2019
Topics: Endovascular Procedures; Hirudins; Peptide Fragments; Recombinant Proteins
PubMed: 31230647
DOI: 10.1016/j.jvs.2019.01.043 -
Kardiologia Polska 2018
Topics: Anticoagulants; Confusion; Heparin; Hirudins; Humans; Peptide Fragments; Recombinant Proteins
PubMed: 29652420
DOI: 10.5603/KP.2018.0074 -
Journal of Cellular and Molecular... Sep 2023Glioma is the most common primary malignant brain tumour, and survival is poor. Hirudin has anticancer pharmacological effects through suppression of glioma cell...
Glioma is the most common primary malignant brain tumour, and survival is poor. Hirudin has anticancer pharmacological effects through suppression of glioma cell progression, but the molecular target and mechanism are poorly understood. In this study, we observed that hirudin dose- and time-dependently inhibited glioma invasion, migration and proliferation. Mechanistically, hirudin activated LC3-II but not Caspase-3 to induce the autophagic death of glioma cells by decreasing the phosphorylation of mTOR and its downstream substrates ULK1, P70S6K and 4EBP1. Furthermore, hirudin inhibited glioma growth and induced changes in autophagy in cell-derived xenograft (CDX) nude mice, with a decrease in mTOR activity and activation of LC3-II. Collectively, our results highlight a new anticancer mechanism of hirudin in which hirudin-induced inhibition of glioma progression through autophagy activation is likely achieved by inhibition of the mTOR signalling pathway, thus providing a molecular basis for hirudin as a potential and effective clinical drug for glioma therapy.
Topics: Mice; Animals; Humans; Hirudins; Mice, Nude; Cell Line, Tumor; TOR Serine-Threonine Kinases; Glioma; Cell Proliferation; Autophagy; Apoptosis
PubMed: 37539490
DOI: 10.1111/jcmm.17851 -
Methods in Enzymology 2016Allosteric networks allow enzymes to transmit information and regulate their catalytic activities over vast distances. In principle, molecular dynamics (MD) simulations... (Review)
Review
Allosteric networks allow enzymes to transmit information and regulate their catalytic activities over vast distances. In principle, molecular dynamics (MD) simulations can be used to reveal the mechanisms that underlie this phenomenon; in practice, it can be difficult to discern allosteric signals from MD trajectories. Here, we describe how MD simulations can be analyzed to reveal correlated motions and allosteric networks, and provide an example of their use on the coagulation enzyme thrombin. Methods are discussed for calculating residue-pair correlations from atomic fluctuations and mutual information, which can be combined with contact information to identify allosteric networks and to dynamically cluster a system into highly correlated communities. In the case of thrombin, these methods show that binding of the antagonist hirugen significantly alters the enzyme's correlation landscape through a series of pathways between Exosite I and the catalytic core. Results suggest that hirugen binding curtails dynamic diversity and enforces stricter venues of influence, thus reducing the accessibility of thrombin to other molecules.
Topics: Allosteric Regulation; Allosteric Site; Catalytic Domain; Chlorides; Heparin; Hirudins; Humans; Molecular Dynamics Simulation; Peptide Fragments; Protein Binding; Protein Conformation, alpha-Helical; Protein Conformation, beta-Strand; Protein Interaction Domains and Motifs; Sodium; Thrombin; Water
PubMed: 27497176
DOI: 10.1016/bs.mie.2016.05.027 -
JACC. Cardiovascular Interventions Jun 2017
Topics: Heparin; Hirudins; Humans; Peptide Fragments; Percutaneous Coronary Intervention; Recombinant Proteins; Registries
PubMed: 28527774
DOI: 10.1016/j.jcin.2017.04.004 -
Journal of Interventional Cardiology Apr 2018
Topics: Anticoagulants; Heparin; Hirudins; Humans; Peptide Fragments; Recombinant Proteins
PubMed: 29644753
DOI: 10.1111/joic.12505 -
Parasitology Research Oct 2022Haematophagous leeches express a broad variety of secretory proteins in their salivary glands, among them are hirudins and hirudin-like factors. Here, we describe the...
Haematophagous leeches express a broad variety of secretory proteins in their salivary glands, among them are hirudins and hirudin-like factors. Here, we describe the identification, molecular and initial functional characterization of Tandem-Hirudin (TH), a novel salivary gland derived factor identified in the Asian medicinal leech, Hirudinaria manillensis. In contrast to the typical structure of hirudins, TH comprises two globular domains arranged in a tandem-like orientation and lacks the elongated C-terminal tail. Similar structures of thrombin inhibitors have so far been identified only in kissing bugs and ticks. Expression of TH was performed in both cell-based and cell-free bacterial systems. A subsequent functional characterization revealed no evidence for a thrombin-inhibitory potency of TH.
Topics: Amino Acid Sequence; Animals; Hirudins; Hirudo medicinalis; Leeches; Thrombin
PubMed: 36006484
DOI: 10.1007/s00436-022-07634-0 -
Science Advances Oct 2020Pathological coagulation, a disorder of blood clotting regulation, induces a number of cardiovascular diseases. A safe and efficient system for the delivery of...
Pathological coagulation, a disorder of blood clotting regulation, induces a number of cardiovascular diseases. A safe and efficient system for the delivery of anticoagulants to mimic the physiological negative feedback mechanism by responding to the coagulation signal changes holds the promise and potential for anticoagulant therapy. Here, we exploit a "closed-loop" controlled release strategy for the delivery of recombinant hirudin, an anticoagulant agent that uses a self-regulated nanoscale polymeric gel. The cross-linked nanogel network increases the stability and bioavailability of hirudin and reduces its clearance in vivo. Equipped with the clot-targeted ligand, the engineered nanogels promote the accumulation of hirudin in the fibrous clots and adaptively release the encapsulated hirudin upon the thrombin variation during the pathological proceeding of thrombus for potentiating anticoagulant activity and alleviating adverse effects. We show that this formulation efficiently prevents and inhibits the clot formation on the mouse models of pulmonary embolism and thrombosis.
Topics: Animals; Anticoagulants; Blood Coagulation; Hirudins; Mice; Recombinant Proteins; Thrombosis
PubMed: 33036973
DOI: 10.1126/sciadv.abc0382