Anticoagulants, also known as antithrombotics, are among the most commonly prescribed medications in the United States. Understanding how these medications work, the propensity for interactions with other drugs, dietary factors, and disease states is important for clinicians assessing and providing care to patients in all environments. In this review, we seek to provide essential information for the home health care provider for evaluating patients receiving anticoagulants commonly prescribed in the home health care setting. The low-molecular-weight heparins and vitamin K antagonists are the most commonly used agents for outpatient anticoagulation. New agents, such as the direct factor Xa inhibitors and direct thrombin inhibitors have recently been approved with additional new agents in the approval process and development pipeline. We seek to review the most pertinent information for each of these classes of medications providing information on pharmacology, interactions with other drugs, diet, and diseases and important clinical information.

Anticoagulants are the basis for treatment and prevention of thrombotic diseases. The currently available medicines are associated with a wide range of adverse reactions that mandates developing new anticoagulants. Several lines of evidence support the superiority of factor Xa (FXa) as a promising target to develop novel anticoagulants. This work focuses on the design of direct and indirect FXa inhibitors using an interdisciplinary approach. As indirect FXa inhibitors, a focused library of tetrasulfated N–arylacyl tetrahydroisoquinoline (THIQ) nonsaccharide allosteric antithrombin activators was designed, synthesized, and biochemically evaluated to establish their structure–activity relationship (SAR). An N–arylacyl THIQ analog having carboxylate at position–3, two sulfate groups at positions–5 and –8 of THIQ moiety, butanoyl linker, and two sulfate groups at positions–2 and –5 of the phenolic monocyclic moiety was identified as the most promising nonsaccharide antithrombin activator with KD of 1322 ± 237 μM and acceleration potential of 80–fold. Its biochemical profile indicates a strong possibility that it activates antithrombin by the pre–equilibrium pathway rather than the induced–fit mechanism utilized by heparin analogs. A similar interdisciplinary approach was exploited to design direct FXa inhibitors that possess high selectivity and are potentially orally bioavailable. Structurally, the designed direct FXa inhibitors are neutral THIQ dicarboxamides. THIQ dicarboxamide is a privileged structure with a semi–rigid character, a structural feature that potentially offers high selectivity for targeting FXa over other coagulation and digestive proteases. It can also be thought of as an amino acid–like structure, which affords accessibility to a large number of compounds using well established peptide chemistry. Mechanistically, the designed inhibitors were expected to bind to FXa in the active site and function as orthosteric inhibitors. These direct FXa active site inhibitors are also likely to inhibit clot–bound enzyme. Nearly 60 THIQ dicarboxamides were synthesized and biochemically evaluated. Through detailed SAR analysis, the most potent analog was designed and found to exhibit an IC50 of 270 nM (Ki = 135 nM), an improvement of more than 207–fold over the first inhibitor synthesized in the study. The most potent inhibitor displayed at least 1887–fold selectivity for FXa over other coagulation enzymes and a selectivity index of at least 279–fold over the digestive serine proteases. This analog doubled plasma clotting times at 17–20 μM, which are comparable to those of agents being currently studied in clinical trials. Overall, allosteric and orthosteric approaches led to the design of indirect and direct small molecule inhibitors of FXa based on the THIQ scaffold. This work introduces two promising molecules, a tetrasulfated N–arylacyl THIQ analog as a heparin mimetic and a neutral THIQ dicarboxamide as a potent, selective, and potentially bioavailable peptidomimetic, for further advanced medicinal chemistry studies.

Introduction : L'hémophilie est une maladie génétique de la coagulation due à un déficit en facteur VIII ou en facteur IX. Ces déficits sont responsables d'un déficit du complexe ténase intrinsèque (VIIIa-IXa). De plus, le complexe ténase extrinsèque (facteur tissulaire - VIIa) est physiologiquement rapidement inhibé par le TFPI lié au facteur Xa. Nous avons évalué la capacité d'une forme tronquée du facteur Xa (GDXa), dépourvue de domaine Gla à se lier au TFPI et à soulager l'inhibition physiologique du complexe ténase extrinsèque. Matériel et Méthodes : Dans une première partie, nous avons évalué la capacité du GDXa à restaurer la génération de thrombine de plasmas d'hémophiles A et B sévères sans et avec inhibiteurs. Nous avons également comparé les profils de génération de thrombine obtenus après addition du GDXa à ceux obtenus en présence d'anticorps neutralisants anti-TFPI ou anti-antithrombine. Enfin, nous avons comparé les cinétiques enzymatiques de neutralisation du facteur Xa et du GDXa par le TFPI et l'antithrombine. Dans une seconde partie, nous avons étudié in silico les interactions entre la chaîne lourde du facteur Xa et le TFPI pour détecter les zones d'interaction défavorables. Cette étude a identifié des acides aminés du facteur Xa qui pourraient être substitués pour optimiser l'interaction avec le TFPI. Les résultats in silico ont orienté nos choix de mutagenèse dirigée pour concevoir différents variants moléculaires du GDXa (R138F, R138G, R138I) où l'arginine 138 est substituée. Ces variants protéiques ont été produits de façon recombinante dans des cellules HEK293E. La capacité des différents variants à restaurer la génération de thrombine de plasmas d'hémophiles a été testée avec les surnageants de culture cellulaires correspondants. Résultats : Dans la première partie, nous avons montré que le GDXa est capable de restaurer la génération de thrombine de plasmas d'hémophiles A et B sans et avec inhibiteurs. Comparativement au facteur Xa, le GDXa montre une affinité moindre pour le TFPI tandis que les affinités du GDXa et du facteur Xa pour l'antithrombine sont identiques. Enfin, malgré une demi-vie courte, l'effet du GDXa sur la génération de thrombine est maintenu pendant au moins une heure. Dans la seconde partie, nous avons produit les différents variants R138F, R138G et R138I en cellules HEK293E et montré que les surnageants de culture cellulaire étaient capables de restaurer la génération de thrombine de plasmas d'hémophiles de façon plus efficace que le GDXa. Conclusion : Comme le GDXa est capable de restaurer la génération de thrombine de plasmas d'hémophiles, nos résultats suggèrent que le GDXa pourrait être une alternative efficace aux thérapeutiques hémostatiques court-circuitantes actuelles chez les hémophiles sans ou avec inhibiteurs. Les résultats obtenus renforcent l'hypothèse que l'activité pro-coagulante du GDXa serait liée à la formation d'un complexe GDXa-TFPI limitant la formation du complexe Xa-TFPI nécessaire à l'inhibition physiologique du complexe ténase extrinsèque. De plus, notre approche rationnelle basée sur une étude in silico visant à augmenter l'affinité du TFPI pour le GDXa a permis de produire différents variants moléculaires du GDXa dont l'activité procoagulante in vitro est augmentée par rapport au GDXa.

For the successful food intake by organisms that feed on blood is essentials presence of antihaemostatic molecules such as vasodilators, anticoagulant molecules and apyrases., Although members of family Diplozoidae (Heteronchoinea) are blood-feeding parasites on the gills of the fish, these molecules, that could disrupt host hemostasis, have not yet been identified. Thus, the aim of this study was to find molecules with potential anticoagulant activity in homogenates of whole worm bodies and excretory/secretory products of the members of family Diplozoidae. Furthermore perform bioinformatics analysis of sequences obtained from transcriptom project of Eudiplozoon nipponicum (Heteronchoinea: Diplozoidae) and selected proteins (protein domain) then expressed in a recombinant form. We tested inhibitory activity in excretory-secretory products and homogenates of members family Diplozoidae towards coagulation factors IIa and Xa and their specific fluorogenic with 4 negative and 1 positive results. From the results of two transcriptome analysis we discovered three protein families of potential anticoagulants - annexins, serpins and Kunitz-domain proteins. For further analyses we focused on the Kunitz protein family. These proteins contain one or more structurally related active domains which are able to...