Engineered heparins as new anticoagulant drugs.
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ABSTRACT:
SUBMITTER: Vaidyanathan D
PROVIDER: S-EPMC5412866 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The chapter will review early and more recent seminal contributions to the discovery and characterization of heparanase and non-anticoagulant heparins inhibiting its peculiar enzymatic activity. Indeed, heparanase displays a unique versatility in degrading heparan sulfate chains of several proteoglycans expressed in all mammalian cells. This endo-β-D-glucuronidase is overexpressed in cancer, inflammation, diabetes, atherosclerosis, nephropathies and other pathologies. Starting from known low- or non-anticoagulant heparins, the search for heparanase inhibitors evolved focusing on structure-activity relationship studies and taking advantage of new chemical-physical analytical methods which have allowed characterization and sequencing of polysaccharide chains. New methods to screen heparanase inhibitors and to evaluate their mechanism of action and in vivo activity in experimental models prompted their development. New non-anticoagulant heparin derivatives endowed with anti-heparanase activity are reported. Some leads are under clinical evaluation in the oncology field (e.g., acute myeloid leukemia, multiple myeloma, pancreatic carcinoma) and in other pathological conditions (e.g., sickle cell disease, malaria, labor arrest).
| S-EPMC7142274 | biostudies-literature
Project description:Low-molecular-weight heparins (LMWHs) are carbohydrate-based anticoagulants clinically used to treat thrombotic disorders, but impurities, structural heterogeneity or functional irreversibility can limit treatment options. We report a series of synthetic LMWHs prepared by cost-effective chemoenzymatic methods. The high activity of one defined synthetic LMWH against human factor Xa (FXa) was reversible in vitro and in vivo using protamine, demonstrating that synthetically accessible constructs can have a critical role in the next generation of LMWHs.
| S-EPMC4393012 | biostudies-literature
Project description:Heparin has been widely used as an anticoagulant for more than 80 years. However, there is now considerable evidence that heparin also possesses anti-inflammatory activity, both experimentally and clinically. Importantly in many instances, the anti-inflammatory actions of heparin are independent of anticoagulant activity raising the possibility of developing novel drugs based on heparin that retain the anti-inflammatory activity. Heparin exhibits anti-inflammatory activities via a variety of mechanisms including neutralization of cationic mediators, inhibition of adhesion molecules, and the inhibition of heparanase, all involved in leukocyte recruitment into tissues. It is anticipated that furthering our understanding of the anti-inflammatory actions of heparin will lead to the development of novel anti-inflammatory drugs for a variety of clinical indications.
| S-EPMC3747464 | biostudies-literature
Project description:ObjectiveTo do an indirect comparison analysis of apixaban against dabigatran etexilate (2 doses) and rivaroxaban (1 dose), as well as of rivaroxaban against dabigatranetexilate (2 doses), for their relative efficacy and safety against each other, with particular focus on the secondary prevention population for stroke prevention in atrial fibrillation. A secondary objective was to do the same analysis in the primary prevention cohort.DesignIndirect treatment comparisons of phase III clinical trials of stroke prevention in atrial fibrillation, with a focus on the secondary prevention cohorts. A secondary analysis was done on the primary prevention cohort.Data sourcesMedline and Central (up to June 2012), clinical trials registers, conference proceedings, and websites of regulatory agencies.Study selectionRandomised controlled trials of rivaroxaban, dabigatran, or apixaban compared with warfarin for stroke prevention in atrial fibrillation.ResultsIn the secondary prevention (previous stroke) subgroup, when apixaban was compared with dabigatran (110 mg and 150 mg twice daily) for efficacy and safety endpoints, the only significant difference seen was less myocardial infarction (hazard ratio 0.39, 95% confidence interval 0.16 to 0.95) with apixaban compared with dabigatran 150 mg twice daily. No significant differences were seen in efficacy and most safety endpoints between apixaban or dabigatran 150 mg twice daily versus rivaroxaban. Less haemorrhagic stroke (hazard ratio 0.15, 0.03 to 0.66), vascular death (0.64, 0.42 to 0.99), major bleeding (0.68, 0.47 to 0.99), and intracranial bleeding (0.27, 0.10 to 0.73) were seen with dabigatran 110 mg twice daily versus rivaroxaban. In the primary prevention (no previous stroke) subgroup, apixaban was superior to dabigatran 110 mg twice daily for disabling or fatal stroke (hazard ratio 0.59, 0.36 to 0.97). Compared with dabigatran 150 mg twice daily, apixaban was associated with more stroke (hazard ratio 1.45, 1.01 to 2.08) and with less major bleeding (0.75, 0.60 to 0.94), gastrointestinal bleeding (0.61, 0.42 to 0.89), and other location bleeding (0.74, 0.58 to 0.94). Compared with rivaroxaban, dabigatran 110 mg twice daily was associated with more myocardial infarction events. No significant differences were seen for the main efficacy and safety endpoints between dabigatran 150 mg twice daily and rivaroxaban, or in efficacy endpoints between apixaban and rivaroxaban. Apixaban was associated with less major bleeding (hazard ratio 0.61, 0.48 to 0.78) than rivaroxaban.ConclusionsFor secondary prevention, apixaban, rivaroxaban, and dabigatran had broadly similar efficacy for the main endpoints, although the endpoints of haemorrhagic stroke, vascular death, major bleeding, and intracranial bleeding were less common with dabigatran 110 mg twice daily than with rivaroxaban. For primary prevention, the three drugs showed some differences in relation to efficacy and bleeding. These results are hypothesis generating and should be confirmed in a head to head randomised trial.
| S-EPMC3489505 | biostudies-literature
Project description:We analysed the distribution, structural characteristics, antithrombin-III-binding properties and anticoagulant activities of heparins and heparan sulphates isolated from the tissues of a wide range of vertebrates. Heparin has a curiously limited distribution, since it was absent from lower aquatic vertebrate species, present in only certain organs such as intestine in many higher vertebrates, and completely absent from the rabbit among mammals examined. The heparins were structurally diverse, and they exhibited a broad range of anticoagulant activities, from approx. 50% to 150% of average commercial heparins. Although there was a rough correlation between the anticoagulant potency of the starting isolate and the proportional content of material exhibiting high-affinity binding to the proteinase inhibitor antithrombin III, activities of high-affinity fractions from heparins low in activity overlapped those of low-affinity fractions from highly active heparins. Heparan sulphates, which in contrast were isolated from nearly all vertebrate organs, contained high-affinity subfractions constituting up to 5% of the starting material and possessing anticoagulant potencies of 2-30 units/mg. In consideration of the heparin data, we infer that its biological function is either species-specific or may be served by other molecular elements, and that there exists considerable diversity in the antithrombin-III-binding sequence of heparin. The more-generally distributed glycosaminoglycan heparan sulphate possesses within its variable structure a small high-affinity subfraction with low anticoagulant potency, whether isolated from aorta or other tissues. Although heparan sulphate appears to have an essential function at the cellular level, we suggest that this is probably not that of providing heparin-like antithrombotic effects on vascular surfaces.
| S-EPMC1147022 | biostudies-other
Project description:Affibody molecules can be used as tools for molecular recognition in diagnostic and therapeutic applications. There are several preclinical studies reported on diagnostic and therapeutic use of this molecular class of alternative scaffolds, and early clinical evidence is now beginning to accumulate that suggests the Affibody molecules to be efficacious and safe in man. The small size and ease of engineering make Affibody molecules suitable for use in multispecific constructs where AffiMabs is one such that offers the option to potentiate antibodies for use in complex disease.
| S-EPMC5382565 | biostudies-literature
Project description:Heparin and its low-molecular-weight heparin derivatives are widely used clinical anticoagulants. These drugs are critical for the practice of medicine in applications, including kidney dialysis, cardiopulmonary bypass, and in the management of venous thromboembolism. Currently, these drugs are derived from livestock, primarily porcine intestine and less frequently bovine intestine and bovine lung. The worldwide dependence on the pig as a single dominant animal species has made the supply chain for this critical drug quite fragile, leading to the search for other sources of these drugs, including the expanded use of bovine tissues. A number of laboratories are now also examining the similarities between heparin and low-molecular-weight heparins prepared from porcine and ovine tissues. This study was designed to compare low-molecular-weight heparin prepared from ovine heparin through chemical β-elimination, a process currently used to prepare the low-molecular-weight heparin, enoxaparin. Using top-down, bottom-up, and compositional analyses as well as bioassays, low-molecular-weight heparin derived from ovine intestine was shown to closely resemble enoxaparin. Moreover, the compositions of daughter low-molecular-weight heparins prepared from three unfractionated ovine parent heparins were compared. Ovine enoxaparins had similar molecular weight and in vitro anticoagulant activities as Lovenox. Some disaccharide compositional, oligosaccharide composition at the reducing and nonreducing ends and intact chain compositional differences could be observed between porcine enoxaparin and ovine low-molecular-weight heparin. The similarity of these ovine and porcine heparin products suggests that their preclinical evaluation and ultimately clinical assessment is warranted.
| S-EPMC6714994 | biostudies-literature
Project description:ObjectiveAn increased risk of bleeding is observed in patients receiving activated protein C (APC), which may be a limiting factor for the application of novel APC therapies. Since APC's therapeutic effects often require its cytoprotective activities on cells but not APC's anticoagulant activities, an agent that specifically antagonizes APC's anticoagulant effects but not its cytoprotective effects could provide an effective means to control concerns for risk of bleeding. We hypothesized that superFVa, an engineered activated FVa-variant that restores hemostasis in hemophilia could reduce APC-induced bleeding.Approach and resultsSuperFVa was engineered with mutations of the APC cleavage sites (Arg506/306/679Gln) and a disulfide bond (Cys609-Cys1691) between the A2 and A3 domains, which augment its biological activity and cause high resistance to APC. SuperFVa normalized APC-prolonged clotting times and restored APC-suppressed thrombin generation in human and murine plasma at concentrations where wild-type (wt) FVa did not show effects. Following intravenous injection of APC into BALB/c mice, addition to whole blood ex vivo of superFVa but not wt-FVa significantly normalized whole blood clotting. Blood loss following tail clip or liver laceration was significantly reduced when superFVa was administered intravenously to BALB/c mice prior to intravenous APC-treatment. Furthermore, superFVa abolished mortality (∼50%) associated with excessive bleeding following liver laceration in mice treated with APC.ConclusionsOur results provide proof of concept that superFVa is effective in preventing APC-induced bleeding and may provide therapeutic benefits as a prohemostatic agent in various situations where bleeding is a serious risk.
| S-EPMC4134195 | biostudies-literature
Project description:Heparins extracted from different animal sources have been conventionally considered effective anticoagulant and antithrombotic agents despite of their pharmacological dissimilarities. We performed herein a systematic analysis on the physicochemical properties, disaccharide composition, in vitro anticoagulant potency and in vivo antithrombotic and bleeding effects of several batches of pharmaceutical grade heparins obtained from porcine intestine, bovine intestine and bovine lung. Each of these three heparin types unambiguously presented differences in their chemical structures, physicochemical properties and/or haemostatic effects. We also prepared derivatives of these heparins with similar molecular weight differing exclusively in their disaccharide composition. The derivatives from porcine intestinal and bovine lung heparins were structurally more similar with each other and hence presented close anticoagulant activities whereas the derivative from bovine intestinal heparin had a higher proportion of 6-desulfated ?-glucosamine units and about half anticoagulant activity. Our findings reasonably indicate that pharmaceutical preparations of heparin from different animal sources constitute distinct drugs, thus requiring specific regulatory rules and therapeutic evaluations.
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Project description:Natural monoterpenes and their derivatives are widely considered as effective ingredients for the design and production of new biologically active compounds with high antioxidant, antimicrobial and anti-protozoa properties. In this study, we synthesized two series of thiotherpenoids "sulfide-sulfoxide-sulfone", with different bicyclic monoterpene skeleton (bornane and pinane) structures. The effect of the obtained compounds on platelet aggregation was investigated by using the molecular docking technique. The obtained data revealed that all the synthesized compounds may act as potential inhibitors of platelet aggregation. Moreover, the studied sulfides have shown high antioxidant activity as revealed by lipid peroxidation (LPO) process inhibition in a non-cellular substrate containing animal lipids. The sulfides were able to inhibit erythrocyte oxidative hemolysis, to reduce the accumulation of secondary LPO products in cells and to prevent the oxidation of native oxyhemoglobin. Additionally, the corresponding sulfones and sulfoxides exhibited insignificant antioxidant activity. However, the sulfides were found to exhibit significant antiaggregant and anticoagulant effects. These findings suggest as well that the sulfides could serve as a leader compound for future research and possible practical applications.
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