Low molecular weight heparins: Structural differentiation by spectroscopic and multivariate approaches

Lima, Marcelo A.; Farias, Edson dos Santos; Rudd, Timothy R.; Ebner, Lyvia F.; Gesteira, Tarsis F.; Mendes, Aline; Bouças, Rodrigo Ippolito; Martins, João Roberto Maciel; Hoppensteadt, Debra; Fareed, Jawed; Yates, Edwin A.; Sassaki, Guilherme L.; Tersariol, Ivarne L.S.; Nader, Helena B.

doi:10.1016/j.carbpol.2011.04.021

Cited by 17 publications

(9 citation statements)

References 21 publications

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“…Crowther et al have provided good evidence that this favorable matching of ligands of opposite charge sign is integral to the ability of PS to fully neutralize the anti-FXa activity of UFH. In particular, they and others − have shown that the methods used to prepare LMWHs serve to decrease the average number of sulfate/sulfonate groups per disaccharide unit (for example, enoxaparin, which is prepared by benzylation of UFH followed by alkaline depolymerization, carries on average 2.6 sulfate/sulfonate groups per disaccharide). More significantly, those processing methods also increase the variability in the charge density of the polysaccharide chains, with Crowther et al reporting a low MW component of LMWH having a charge density ca.…”

Section: Results and Discussionmentioning

confidence: 99%

A Polymer Therapeutic Having Universal Heparin Reversal Activity: Molecular Design and Functional Mechanism

Kalathottukaren

Abbina

et al. 2017

Biomacromolecules

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Heparins are widely used to prevent blood clotting during surgeries and for the treatment of thrombosis. However, bleeding associated with heparin therapy is a concern. Protamine, the only approved antidote for unfractionated heparin (UFH) could cause adverse cardiovascular events. Here, we describe a unique molecular design used in the development of a synthetic dendritic polycation named as universal heparin reversal agent (UHRA), an antidote for all clinically used heparin anticoagulants. We elucidate the mechanistic basis for the selectivity of UHRA to heparins and its nontoxic nature. Isothermal titration calorimetry based binding studies of UHRAs having different methoxypolyethylene glycol (mPEG) brush structures with UFH as a function of solution conditions, including ionic strength, revealed that mPEG chains impose entropic penalty to the electrostatic binding. Binding studies confirm that, unlike protamine or N-UHRA (a truncated analogue of UHRA with no mPEG chains), the mPEG chains in UHRA avert nonspecific interactions with blood proteins and provide selectivity toward heparins through a combined steric repulsion and Donnan shielding effect (a balance of F and F). Clotting assays reveal that UHRA with mPEG chains did not adversely affect clotting, and neutralized UFH over a wide range of concentrations. Conversely, N-UHRA and protamine display intrinsic anticoagulant activity and showed a narrow concentration window for UFH neutralization. In addition, we found that mPEG chains regulate the size of antidote-UFH complexes, as revealed by atomic force microscopy and dynamic light scattering studies. UHRA molecules with mPEG chains formed smaller complexes with UFH, compared to N-UHRA and protamine. Finally, fluorescence and ELISA experiments show that UHRA disrupts antithrombin-UFH complexes to neutralize heparin's activity.

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Section: Results and Discussionmentioning

confidence: 99%

A Polymer Therapeutic Having Universal Heparin Reversal Activity: Molecular Design and Functional Mechanism

Kalathottukaren

Abbina

et al. 2017

Biomacromolecules

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“… a, Percent substitution values were obtained by integration of HSQC spectra as described by Lima et al, 2011a. UFH, unfractionated heparins; LMWHs, low molecular weight heparins; A NS , 2‐deoxy‐2‐sulfoamino‐ D ‐glucopyranose; I 2S , 2‐ O ‐sulfo‐iduronic acid; G, glucuronic acid; A 3S , 2‐deoxy‐3‐ O ‐sulfo‐2‐amino‐ D ‐glucopyranose; A Nac , 2‐deoxy‐2‐acetylamino‐ D ‐glucopyranose; αred, terminal reducing residue with a configuration; 1,6‐an.A, 2‐amino‐1,6‐anhydro‐2‐deoxy‐b‐ D ‐glucopyranose; 1,6‐an.M, 2‐amino‐1,6‐anhydro‐2‐deoxy‐b‐ D ‐mannopyranose; M NS , 2‐deoxy‐2‐ sulfamino‐ D ‐mannopyranose; ΔU 2S , 2‐ O ‐sulfo‐4‐deoxy‐a‐ L ‐threo‐hex‐4‐enopyranosil uronic acid;U, Δ4‐deoxy‐a‐ L ‐threo‐hex‐4‐enopyranosil uronic acid. …”

Section: Resultsmentioning

confidence: 99%

“…Partially and non‐specifically desulfated heparin was obtained by solvolytic desulfation by DMSO of the heparin pyridium salt [Nagasawa et al, 1979]. The amount of sulfate in heparin was determined by 2D Nuclear Magnetic Resonance (NMR) and other chemical measurements as previously described [Dodgson and Price, 1962; Nader and Dietrich, 1977; Lima et al, 2011a]. Molecular weight was determined by gel permeation chromatography using a HPLC system (Shimadzu, Kyoto, Japan) with the outlet of the joint columns (TSK G3000SW and TSK G2000SW, TosoHaas, Tokyo, Japan) attached to an UV detector.…”

Section: Methodsmentioning

confidence: 99%

Chemical reduction of carboxyl groups in heparin abolishes its vasodilatory activity

Paredes‐Gamero

Medeiros

Lima

et al. 2012

J of Cellular Biochemistry

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Previous studies have shown that heparin induces vascular relaxation via integrin-dependent nitric oxide (NO)-mediated activation of the muscarinic receptor. The aim of this study was to identify the structural features of heparin that are necessary for the induction of vasodilatation. To address this issue, we tested heparin from various sources for their vasodilatation activities in the rat aorta ring. Structural and chemical characteristics of heparin, such as its molecular weight and substitution pattern, did not show a direct correlation with the vasodilation activity. Principal component analysis (PCA) of circular dichroism (CD), (1)H-nuclear magnetic resonance (NMR) and vasodilation activity measurements confirmed that there is no direct relationship between the physico-chemical nature and vasodilation activity of the tested heparin samples. To further understand these observations, unfractionated heparin (UFH) from bovine intestinal mucosa, which showed the highest relaxation effect, was chemically modified. Interestingly, non-specific O- and N-desulfation of heparin reduced its anticoagulant, antithrombotic, and antihemostatic activities, but had no effect on its ability to induce vasodilation. On the other hand, chemical reduction of the carboxyl groups abolished heparin-induced vasodilation and reduced the affinity of heparin toward the extracellular matrix (ECM). In addition, dextran and dextran sulfate (linear non-sulfated and highly sulfated polysaccharides, respectively) did not induce significant relaxation, showing that the vasodilation activity of polysaccharides is neither charge-dependent nor backbone unspecific. Our results suggest that desulfated heparin molecules may be used as vasoactive agents due to their low side effects.

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“…Furthermore, although FDP is sometimes referred to as an “ultra” LMWH, it has a distinct chemical structure and should also not be considered interchangeable with LMWHs [ 73 ]. Several CPGs recommended LMWH as the preferred anticoagulant class over alternative medications (e.g., LMWHs are favored over UFHs because their pharmacokinetic profile is more predictable, they have improved bioavailability, and are easier to use [ 73 , 74 ]); however, broad generalizations such as these provide somewhat limited guidance as specific LMWHs may in fact be more preferable to others in specific situations. Owing to this scarcity of evidence, further studies should be conducted to establish the comparative efficacy and safety of specific LMWHs against each other and FDP across clinical scenarios.…”

Section: Discussionmentioning

confidence: 99%

A systematic review of clinical practice guidelines on the use of low molecular weight heparin and fondaparinux for the treatment and prevention of venous thromboembolism: Implications for research and policy decision-making

et al. 2018

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BackgroundVenous thromboembolism (VTE) is a major global cause of morbidity and mortality. Low molecular weight heparin (LMWH) and fondaparinux (FDP) are frequently used to treat and prevent VTE and have a variety of safety and practical advantages over other anticoagulants, including use in outpatient settings. These medications are commonly listed on drug formularies, which act as a gateway for health plan prescription coverage by outlining the circumstances under which patients will be covered for specific drugs and drug products. Because patient access to medications is impacted by the nature of their listing on formularies, they must be rigorously reviewed and modernized as new evidence emerges.MethodsAs part of a broader drug class review team, we completed a systematic review of clinical practice guidelines to determine whether the recommendations they reported aligned with the indications listed for the coverage of LMWH and FDP in an outpatient drug formulary. Guideline quality was assessed using the Appraisal of Guidelines for Research & Evaluation (AGREE) II tool. Recommendation matrices were used to systematically compare, categorize, and summarize included recommendations.ResultsTwenty-seven guidelines were included from which 168 eligible recommendations were identified. Generally, AGREE II domains were adequately addressed; however, domain five (applicability) was poorly addressed. Most recommendations were based on moderate- to low-quality/limited evidence and reported on the use of LMWHs generally; few reported on specific agents.ConclusionsOur findings contributed to the recommendation that the formulary listing for LMWH and FDP be streamlined to include coverage for specific outpatient indications. The paucity of available evidence on the comparative efficacy of specific LMWH agents against each other and FDP limited agent-specific listing recommendations, highlighting the need for high-quality comparative studies on this topic.

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Low molecular weight heparins: Structural differentiation by spectroscopic and multivariate approaches

Cited by 17 publications

References 21 publications

A Polymer Therapeutic Having Universal Heparin Reversal Activity: Molecular Design and Functional Mechanism

A Polymer Therapeutic Having Universal Heparin Reversal Activity: Molecular Design and Functional Mechanism

Chemical reduction of carboxyl groups in heparin abolishes its vasodilatory activity

A systematic review of clinical practice guidelines on the use of low molecular weight heparin and fondaparinux for the treatment and prevention of venous thromboembolism: Implications for research and policy decision-making

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