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Chabata CV, Yu H, Ke L, Frederiksen JW, Patel PA, Sullenger BA, Thalji NK. Andexanet alfa-associated heparin resistance in cardiac surgery: mechanism and in vitro perspectives. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.09.612152. [PMID: 39314402 PMCID: PMC11419022 DOI: 10.1101/2024.09.09.612152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Background Andexanet alfa (andexanet) is the only FDA-approved antidote for direct factor Xa (FXa) inhibitors but has been reported to cause resistance to unfractionated heparin (UFH). This has delayed anticoagulation for procedures requiring cardiopulmonary bypass (CPB). The mechanism, andexanet and UFH dose dependence, and thrombotic risk of andexanet-associated heparin resistance are unknown. Methods The effect of andexanet in vitro was determined using activated clotting times (ACT) and thromboelastography (TEG). Ex vivo CPB circuits were used to determine whether andexanet impaired anticoagulation for extracorporeal circulation. Kinetics of antithrombin (AT) inhibition of FXa and thrombin were measured in the presence of andexanet. Equilibrium modeling and thrombin generation assay (TGA) validation were used to predict the role of andexanet, AT, and UFH concentrations in andexanet-associated heparin resistance. Results Andexanet prevented UFH-mediated prolongation of ACT and TEG times. At lower concentrations of andexanet, heparin resistance could be overcome with suprapharmacologic doses of UFH, but not at higher andexanet concentrations. Andexanet rendered standard doses of UFH inadequate to prevent circuit thrombosis, and suprapharmacologic UFH doses were only partially able to overcome this. Scanning electron microscopy demonstrated coagulation activation in circuits. Andexanet prevented UFH enhancement of AT-mediated inhibition of FXa and thrombin. Equilibrium modeling and TGA validation demonstrated that andexanet creates a triphasic equilibrium with UFH and AT: initial UFH unresponsiveness, normal UFH responsiveness when andexanet is depleted, and finally AT depletion. Sufficient CPB heparinization can only occur at low therapeutic andexanet doses and normal AT levels. Higher andexanet doses or AT deficiency may require both AT supplementation and very high UFH doses. Conclusions Andexanet causes heparin resistance due to redistribution of UFH-bound AT. If andexanet cannot be avoided prior to heparinization and direct thrombin inhibitors are undesirable, our in vitro study suggests excess UFH should be considered as a potential strategy prior to AT supplementation. Highlights Andexanet alfa causes heparin resistance not by depleting antithrombin, but rather by sequestering heparin-bound antithrombin such that it cannot act as an anticoagulant.Heparin responsiveness in the presence of Andexanet alfa is triphasic such that the effect of a dose of heparin can now be predicted in vitro based on the relative concentrations of andexanet, heparin, and antithrombin.The in vitro insights provided by this work provide a rational starting point for further clinical elucidation of the problem and management of andexanet-associated heparin resistance.
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Andrabi SM, Kumar A. A kaolin/calcium incorporated shape memory and antimicrobial chitosan-dextran based cryogel as an efficient haemostatic dressing for uncontrolled hemorrhagic wounds. BIOMATERIALS ADVANCES 2023; 150:213424. [PMID: 37068405 DOI: 10.1016/j.bioadv.2023.213424] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/28/2023] [Accepted: 04/06/2023] [Indexed: 04/19/2023]
Abstract
Increased mortalities associated with uncontrolled and excessive bleeding is still of paramount concern in the clinics, caregivers and military medics. Herein, we designed a shape memory cryogel based on chitosan (C) and functionalized-dextran (D), incorporated with Kaolin (K) and calcium (Ca2+) as haemostatic agents. The developed cryogel (CDKCa) exhibits a uniform interconnected porous architecture with profound fluid absorption ability, rapid blood clotting, stable clot formation and good antibacterial activity. The CDKCa elucidates significantly less clotting time (~30 s; in-vitro) and increased aggregation and activation of platelets/red blood cells in comparison to the control groups and commercial dressings (Axiostat and QuikClot). The developed CDKCa also significantly reduced the aPTT and PT values by ~58 % and 31 % respectively, leading to the activation of intrinsic and extrinsic coagulation cascades. The CDKCa cryogel displays enhanced mechanical stability, flexibility and a good shape memory, a property quintessential to cease uncontrolled bleeding in irregular and non-compressible wounds. Further, the Kaolin and Ca2+ incorporated shape memory CDKCa cryogel demonstrates a rapid blood coagulation and stable clot formation in different compressible and non-compressible rat liver and femur hemorrhagic models. In summary, the endorsed results of CDKCa suggest that the design, fabrication and excellent clotting ability may attribute to high haemostatic efficiency of CDKCa dressing and have a great potential to prevent uncontrollable hemorrhages.
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Affiliation(s)
- Syed Muntazir Andrabi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, UP, India; Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, UP, India
| | - Ashok Kumar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, UP, India; Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, UP, India; Center for Nanosciences, Indian Institute of Technology Kanpur, Kanpur 208016, UP, India; The Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur 208016, UP, India; Centre of Excellence, Gangwal School of Medical Sciences and Technology, Indian Institute of Technology Kanpur, Kanpur 208016, UP, India.
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Yu H, Frederiksen J, Sullenger BA. Applications and future of aptamers that achieve rapid-onset anticoagulation. RNA (NEW YORK, N.Y.) 2023; 29:455-462. [PMID: 36697262 PMCID: PMC10019365 DOI: 10.1261/rna.079503.122] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In this short Perspective, we discuss the history of, and recent progress toward, the development of aptamers that can serve as rapid onset anticoagulants during cardiopulmonary bypass (CPB), extracorporeal membrane oxygenation (ECMO), and catheter-based diagnostic and interventional procedures, several million of which are performed each year worldwide. Aptamer anticoagulants provide potent and antidote-controllable anticoagulation and have low immunogenicity. New methods of aptamer isolation and engineering have not only improved the quality of aptamers, but also accelerated their development. Unfortunately, no aptamer identified to date can produce an anticoagulant effect as potent as that produced by unfractionated heparin (UFH), the standard anticoagulant for CPB. We have suggested several possible strategies to amplify the anticoagulant potency of existing aptamer anticoagulants.
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Affiliation(s)
- Haixiang Yu
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - James Frederiksen
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Bruce A Sullenger
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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Chabata CV, Frederiksen JW, Olson LB, Naqvi IA, Hall SE, Gunaratne R, Kraft BD, Que LG, Chen L, Sullenger BA. Combining Heparin and a FX/Xa Aptamer to Reduce Thrombin Generation in Cardiopulmonary Bypass and COVID-19. Nucleic Acid Ther 2022; 32:139-150. [PMID: 35021888 PMCID: PMC9221171 DOI: 10.1089/nat.2021.0077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/10/2021] [Indexed: 11/13/2022] Open
Abstract
Known limitations of unfractionated heparin (UFH) have encouraged the evaluation of anticoagulant aptamers as alternatives to UFH in highly procoagulant settings such as cardiopulmonary bypass (CPB). Despite progress, these efforts have not been totally successful. We take a different approach and explore whether properties of an anticoagulant aptamer can complement UFH, rather than replace it, to address shortcomings with UFH use. Combining RNA aptamer 11F7t, which targets factor X/Xa, with UFH (or low molecular weight heparin) yields a significantly enhanced anticoagulant cocktail effective in normal and COVID-19 patient blood. This aptamer-UFH combination (1) supports continuous circulation of human blood through an ex vivo membrane oxygenation circuit, as is required for patients undergoing CPB and COVID-19 patients requiring extracorporeal membrane oxygenation, (2) allows for a reduced level of UFH to be employed, (3) more effectively limits thrombin generation compared to UFH alone, and (4) is rapidly reversed by the administration of protamine sulfate, the standard treatment for reversing UFH clinically following CPB. Thus, the combination of factor X/Xa aptamer and UFH has significantly improved anticoagulant properties compared to UFH alone and underscores the potential of RNA aptamers to improve medical management of acute care patients requiring potent yet rapidly reversible anticoagulation.
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Affiliation(s)
- Charlene V. Chabata
- Department of Surgery, Department of Medicine, Duke University Medical Centre, Durham, North Carolina, USA
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | - James W. Frederiksen
- Department of Surgery, Department of Medicine, Duke University Medical Centre, Durham, North Carolina, USA
| | - Lyra B. Olson
- Department of Surgery, Department of Medicine, Duke University Medical Centre, Durham, North Carolina, USA
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
- Medical Scientist Training Program, Duke University, Durham, North Carolina, USA
| | - Ibtehaj A. Naqvi
- Department of Surgery, Department of Medicine, Duke University Medical Centre, Durham, North Carolina, USA
- Department of Anesthesiology, Department of Medicine, Duke University Medical Centre, Durham, North Carolina, USA
| | - Sharon E. Hall
- Division of Hematology, Department of Medicine, Duke University Medical Centre, Durham, North Carolina, USA
| | - Ruwan Gunaratne
- Department of Medicine, Stanford University Medical Center, Stanford, California, USA
| | - Bryan D. Kraft
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Loretta G. Que
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Lingye Chen
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Bruce A. Sullenger
- Department of Surgery, Department of Medicine, Duke University Medical Centre, Durham, North Carolina, USA
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
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Soule EE, Yu H, Olson L, Naqvi I, Kumar S, Krishnaswamy S, Sullenger BA. Generation of an anticoagulant aptamer that targets factor V/Va and disrupts the FVa-membrane interaction in normal and COVID-19 patient samples. Cell Chem Biol 2022; 29:215-225.e5. [PMID: 35114109 PMCID: PMC8808741 DOI: 10.1016/j.chembiol.2022.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/11/2021] [Accepted: 01/11/2022] [Indexed: 11/29/2022]
Abstract
Coagulation cofactors profoundly regulate hemostasis and are appealing targets for anticoagulants. However, targeting such proteins has been challenging because they lack an active site. To address this, we isolate an RNA aptamer termed T18.3 that binds to both factor V (FV) and FVa with nanomolar affinity and demonstrates clinically relevant anticoagulant activity in both plasma and whole blood. The aptamer also shows synergy with low molecular weight heparin and delivers potent anticoagulation in plasma collected from patients with coronavirus disease 2019 (COVID-19). Moreover, the aptamer's anticoagulant activity can be rapidly and efficiently reversed using protamine sulfate, which potentially allows fine-tuning of aptamer's activity post-administration. We further show that the aptamer achieves its anticoagulant activity by abrogating FV/FVa interactions with phospholipid membranes. Our success in generating an anticoagulant aptamer targeting FV/Va demonstrates the feasibility of using cofactor-binding aptamers as therapeutic protein inhibitors and reveals an unconventional working mechanism of an aptamer by interrupting protein-membrane interactions.
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Affiliation(s)
- Erin E. Soule
- Department of Pharmacology & Cancer Biology, Duke University, Durham, NC 27710, USA,Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Haixiang Yu
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Lyra Olson
- Department of Pharmacology & Cancer Biology, Duke University, Durham, NC 27710, USA,Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Ibtehaj Naqvi
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Shekhar Kumar
- The Children’s Hospital of Philadelphia, Division of Hematology, Department of Pediatrics, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Sriram Krishnaswamy
- The Children’s Hospital of Philadelphia, Division of Hematology, Department of Pediatrics, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Bruce A. Sullenger
- Department of Pharmacology & Cancer Biology, Duke University, Durham, NC 27710, USA,Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA,Corresponding author
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Koudrina A, McConnell EM, Zurakowski JA, Cron GO, Chen S, Tsai EC, DeRosa MC. Exploring the Unique Contrast Properties of Aptamer-Gadolinium Conjugates in Magnetic Resonance Imaging for Targeted Imaging of Thrombi. ACS APPLIED MATERIALS & INTERFACES 2021; 13:9412-9424. [PMID: 33395250 DOI: 10.1021/acsami.0c16666] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Objective: An important clinical question in the determination of the extent of thrombosis-related vascular conditions is the identification of blood clot location. Fibrin is a major molecular constituent of blood clots and can, therefore, be utilized in molecular imaging. In this proof-of-concept study, we sought to prepare a fibrin-targeting magnetic resonance imaging contrast agent, using a Gd(III)-loaded fibrinogen aptamer (FA) chelate conjugate (Gd(III)-NOTA-FA) (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetic acid), to endow the ability to specifically accumulate at the location of blood clots, thereby enhancing contrast capabilities. Methods: The binding affinity of FA for fibrin was confirmed by fluorescence microscopy and microscale thermophoresis. The preparation and effective loading of the chelate-aptamer conjugates were confirmed by mass spectrometry and a xylenol orange colorimetric test. Longitudinal and transverse relaxivities and the effects of target binding were assessed using T1- and T2-map sequences at 7 T. T1- and T2-weighted images were acquired after blood clots were treated with Gd(III)-NOTA-FA. Collagen was used as the protein control, while an unrelated aptamer sequence, FB139, was used as the aptamer control. Results: FA demonstrated a high affinity and selectivity toward the polymeric protein, with a Kd of 16.6 nM, confirming an avidity over fibrinogen. The longitudinal (r1) and transverse (r2) relaxivities of Gd(III)-NOTA-FA demonstrated that conjugation to the long aptamer strand shortened T1 relaxation times and increased T2 relaxation times (3.04 and 38.7 mM-1 s-1, respectively). These effects were amplified by binding to the fibrin target (1.73 and 46.5 mM-1 s-1, respectively). In vitro studies with thrombin-polymerized human blood (clots) in whole blood showed an unexpected enhancement of signal intensity (hyperintense) produced exclusively at the location of the clot during the T2-weighted scan, while the presence of fibrinogen within a whole blood pool resulted in T1 signal intensity enhancement throughout the pool. This is advantageous, as simply reversing the type of a scan from a typical T1-weighted to a T2-weighted would allow to selectively highlight the location of blood clots. Conclusions: Gd(III)-NOTA-FA can be used for molecular imaging of thrombi, through fibrin-targeted delivery of contrast to the location of blood clots in T2-weighted scans.
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Affiliation(s)
- Anna Koudrina
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Erin M McConnell
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street W, Hamilton, ON L8S 4L8, Canada
| | - Joseph A Zurakowski
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Greg O Cron
- The Ottawa Hospital, Ottawa, ON K1Y 4E9, Canada
- Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada
- Department of Radiology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Suzan Chen
- The Ottawa Hospital, Ottawa, ON K1Y 4E9, Canada
- Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada
| | - Eve C Tsai
- The Ottawa Hospital, Ottawa, ON K1Y 4E9, Canada
- Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada
| | - Maria C DeRosa
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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Tran PHL, Xiang D, Tran TTD, Yin W, Zhang Y, Kong L, Chen K, Sun M, Li Y, Hou Y, Zhu Y, Duan W. Exosomes and Nanoengineering: A Match Made for Precision Therapeutics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1904040. [PMID: 31531916 DOI: 10.1002/adma.201904040] [Citation(s) in RCA: 133] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/02/2019] [Indexed: 05/28/2023]
Abstract
Targeted exosomal delivery systems for precision nanomedicine attract wide interest across areas of molecular cell biology, pharmaceutical sciences, and nanoengineering. Exosomes are naturally derived 50-150 nm nanovesicles that play important roles in cell-to-cell and/or cell-to-tissue communications and cross-species communication. Exosomes are also a promising class of novel drug delivery vehicles owing to their ability to shield their payload from chemical and enzymatic degradations as well as to evade recognition by and subsequent removal by the immune system. Combined with a new class of affinity ligands known as aptamers or chemical antibodies, molecularly targeted exosomes are poised to become the next generation of smartly engineered nanovesicles for precision medicine. Here, recent advances in targeted exosomal delivery systems engineered by aptamer for future strategies to promote human health using this class of human-derived nanovesicles are summarized.
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Affiliation(s)
- Phuong H L Tran
- School of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, 3216, Australia
| | - Dongxi Xiang
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, 77 Avenue Louise Pasteur, Boston, MA, 02115, USA
| | - Thao T D Tran
- Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Wang Yin
- School of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, 3216, Australia
| | - Yumei Zhang
- School of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, 3216, Australia
| | - Lingxue Kong
- Institute for Frontier Materials, Deakin University, Geelong, Victoria, 3216, Australia
| | - Kuisheng Chen
- Department of Pathology, The First Affiliated Hospital, Zhengzhou University, He'nan Key Laboratory of Tumor Pathology, Zhengzhou, 450052, China
| | - Miaomiao Sun
- Department of Pathology, The First Affiliated Hospital, Zhengzhou University, He'nan Key Laboratory of Tumor Pathology, Zhengzhou, 450052, China
| | - Yong Li
- Cancer Care Centre, St George Hospital, Kogarah, and St George and Sutherland Clinical School, University of New South Wales, Kensington, NSW, 2217, Australia
| | - Yingchun Hou
- Laboratory of Tumor Molecular and Cellular Biology, College of Life Sciences, Shaanxi Normal University, 620 West Chang'an Avenue, Xi'an, Shaanxi, 710119, China
| | - Yimin Zhu
- CAS Key Laboratory of Nano-Bio Interface, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Wei Duan
- School of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, 3216, Australia
- GenePharma-Deakin Joint Laboratory of Aptamer Medicine, Suzhou, 215123, China
- GenePharma-Deakin Joint Laboratory of Aptamer Medicine, Waurn Ponds, Victoria, 3216, Australia
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Abstract
PURPOSE OF REVIEW Since the selection of the first thrombin-binding aptamer in 1992, the use of nucleic acid aptamers to target specific coagulation factors has emerged as a valuable approach for generating novel anticoagulant and procoagulant therapeutics. Herein, we highlight the most recent discoveries involving application of aptamers for those purposes. RECENT FINDINGS Learning from the successes and pitfalls of the FIXa-targeting aptamer pegnivacogin in preclinical and clinical studies, the latest efforts to develop antidote-controllable anticoagulation strategies for cardiopulmonary bypass that avoid unfractionated heparin involve potentiation of the exosite-binding factor X (FX)a aptamer 11F7t by combination with either a small molecule FXa catalytic site inhibitor or a thrombin aptamer. Recent work has also focused on identifying aptamer inhibitors of contact pathway factors such as FXIa and kallikrein, which may prove to be well tolerated and effective antithrombotic agents in certain clinical settings. Finally, new approaches to develop procoagulant aptamers to control bleeding associated with hemophilia and other coagulopathies involve targeting activated protein C and tissue plasminogen activator. SUMMARY Overall, these recent findings exemplify the versatility of aptamers to modulate a variety of procoagulant and anticoagulant factors, along with their capacity to be used complementarily with other aptamers or drugs for wide-ranging applications.
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Zhao KN, Dimeski G, de Jersey J, Johnson LA, Grant M, Masci PP, Lavin MF. Next-generation rapid serum tube technology using prothrombin activator coagulant: fast, high-quality serum from normal samples. ACTA ACUST UNITED AC 2018; 57:483-497. [DOI: 10.1515/cclm-2018-0397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/31/2018] [Indexed: 01/30/2023]
Abstract
Abstract
Background
Incomplete blood clotting or latent clotting in serum is a common laboratory problem, especially for patients on anticoagulant therapy or when serum tubes are centrifuged before clotting is completed. We describe a novel approach to producing high-quality serum using snake venom prothrombin activator complex (OsPA) as an additive in blood collection tubes for non-anticoagulated (normal) individuals.
Methods
Plasma clotting assays were performed using a Hyland-Clotek instrument. Blood clotting was visually observed, and thromboelastography was also performed to determine the important parameters of coagulation. Thrombin generation was assayed using the chromogenic substrate S-2238, and biochemical analytes in the serum were determined on chemistry and immunoassay analysers. Fibrinogen was determined by either ELISA or Clauss fibrinogen assay.
Results
We initially showed that OsPA had strong coagulation activity in clotting not only recalcified citrated plasma and recalcified citrated whole blood, but also fresh whole blood in a clinical setting. The use of TEG clearly showed improved speed of clotting and generation of a firmer clot. We also showed that the use of OsPA to produce serum did not interfere with the determination of commonly measured biochemical analytes. The underlying clotting mechanism involves a burst of thrombin production at the initial stages of the clotting process upon contact with prothrombin in blood.
Conclusions
These results demonstrate rapid generation of high-quality serum, contributing to faster turnaround times with standardised quality samples, for accurate analyte determinations in normal individuals.
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Affiliation(s)
- Kong-Nan Zhao
- Centre for Venomics Research, School of Medicine , The University of Queensland, Translational Research Institute , Woolloongabba, QLD , Australia
- Centre for Clinical Research, The University of Queensland, Royal Brisbane and Women’s Hospital Campus , Herston, Brisbane, QLD , Australia
| | - Goce Dimeski
- Chemical Pathology, Princess Alexandra Hospital , Woolloongabba, Brisbane, QLD , Australia
- School of Chemistry and Molecular Biosciences , The University of Queensland, Brisbane , QLD , Australia
| | - John de Jersey
- School of Chemistry and Molecular Biosciences , The University of Queensland, Brisbane , QLD , Australia
| | - Lambro A. Johnson
- Centre for Venomics Research, School of Medicine , The University of Queensland, Translational Research Institute , Woolloongabba, QLD , Australia
| | | | - Paul P. Masci
- Centre for Venomics Research, School of Medicine , The University of Queensland, Translational Research Institute , Woolloongabba, QLD , Australia
- Centre for Clinical Research, The University of Queensland, Royal Brisbane and Women’s Hospital Campus , Herston, Brisbane, QLD , Australia
| | - Martin F. Lavin
- Centre for Clinical Research, The University of Queensland, Royal Brisbane and Women’s Hospital Campus , Herston, Brisbane, QLD 4029 , Australia , Phone: +61 07 3346 6045, Fax: +61 07 3346 5509
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Gunaratne R, Kumar S, Frederiksen JW, Stayrook S, Lohrmann JL, Perry K, Bompiani KM, Chabata CV, Thalji NK, Ho MD, Arepally G, Camire RM, Krishnaswamy S, Sullenger BA. Combination of aptamer and drug for reversible anticoagulation in cardiopulmonary bypass. Nat Biotechnol 2018; 36:606-613. [PMID: 29863725 PMCID: PMC6349032 DOI: 10.1038/nbt.4153] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 03/27/2018] [Indexed: 02/05/2023]
Abstract
Unfractionated heparin (UFH), the standard anticoagulant for cardiopulmonary bypass (CPB) surgery, carries a risk of post-operative bleeding and is potentially harmful in patients with heparin-induced thrombocytopenia-associated antibodies. To improve the activity of an alternative anticoagulant, the RNA aptamer 11F7t, we solved X-ray crystal structures of the aptamer bound to factor Xa (FXa). The finding that 11F7t did not bind the catalytic site suggested that it could complement small-molecule FXa inhibitors. We demonstrate that combinations of 11F7t and catalytic-site FXa inhibitors enhance anticoagulation in purified reaction mixtures and plasma. Aptamer-drug combinations prevented clot formation as effectively as UFH in human blood circulated in an extracorporeal oxygenator circuit that mimicked CPB, while avoiding side effects of UFH. An antidote could promptly neutralize the anticoagulant effects of both FXa inhibitors. Our results suggest that drugs and aptamers with shared targets can be combined to exert more specific and potent effects than either agent alone.
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Affiliation(s)
- Ruwan Gunaratne
- Duke University, Department of Pharmacology and Cancer Biology, Durham, NC 27710
- Duke University, Medical Scientist Training Program, Durham, NC 27710
| | - Shekhar Kumar
- Research Institute, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
| | | | - Steven Stayrook
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Kay Perry
- Northeastern Collaborative Access Team (NE-CAT) and Departments of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Argonne, IL 60439
| | | | - Charlene V. Chabata
- Duke University, Department of Pharmacology and Cancer Biology, Durham, NC 27710
| | - Nabil K. Thalji
- Research Institute, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA 19104
| | - Michelle D. Ho
- Research Institute, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
| | | | - Rodney M. Camire
- Research Institute, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA 19104
| | - Sriram Krishnaswamy
- Research Institute, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA 19104
| | - Bruce A. Sullenger
- Duke University, Department of Pharmacology and Cancer Biology, Durham, NC 27710
- Duke University, Department of Surgery, Durham, NC 27710
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11
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Abstract
Nucleic acid aptamers, often termed 'chemical antibodies', are functionally comparable to traditional antibodies, but offer several advantages, including their relatively small physical size, flexible structure, quick chemical production, versatile chemical modification, high stability and lack of immunogenicity. In addition, many aptamers are internalized upon binding to cellular receptors, making them useful targeted delivery agents for small interfering RNAs (siRNAs), microRNAs and conventional drugs. However, several crucial factors have delayed the clinical translation of therapeutic aptamers, such as their inherent physicochemical characteristics and lack of safety data. This Review discusses these challenges, highlighting recent clinical developments and technological advances that have revived the impetus for this promising class of therapeutics.
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Affiliation(s)
- Jiehua Zhou
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd, Duarte, CA 91010, USA
| | - John Rossi
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd, Duarte, CA 91010, USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd, Duarte, CA 91010, USA
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Soule EE, Bompiani KM, Woodruff RS, Sullenger BA. Targeting Two Coagulation Cascade Proteases with a Bivalent Aptamer Yields a Potent and Antidote-Controllable Anticoagulant. Nucleic Acid Ther 2015; 26:1-9. [PMID: 26584417 DOI: 10.1089/nat.2015.0565] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Potent and rapid-onset anticoagulation is required for several clinical settings, including cardiopulmonary bypass surgery. In addition, because anticoagulation is associated with increased bleeding following surgery, the ability to rapidly reverse such robust anticoagulation is also important. Previously, we observed that no single aptamer was as potent as heparin for anticoagulating blood. However, we discovered that combinations of two aptamers were as potent as heparin. Herein, we sought to combine two individual anticoagulant aptamers into a single bivalent RNA molecule in an effort to generate a single molecule that retained the potent anticoagulant activity of the combination of individual aptamers. We created four bivalent aptamers that can inhibit Factor X/Xa and prothrombin/thrombin and anticoagulate plasma, as well as the combination of individual aptamers. Detailed characterization of the shortest bivalent aptamer indicates that each aptamer retains full binding and functional activity when presented in the bivalent context. Finally, reversal of this bivalent aptamer with a single antidote was explored, and anticoagulant activity could be rapidly turned off in a dose-dependent manner. These studies demonstrate that bivalent anticoagulant aptamers represent a novel and potent approach to actively and reversibly control coagulation.
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Affiliation(s)
- Erin E Soule
- Departments of Surgery and Pharmacology and Cancer Biology, Duke University Medical Center , Durham, North Carolina
| | - Kristin M Bompiani
- Departments of Surgery and Pharmacology and Cancer Biology, Duke University Medical Center , Durham, North Carolina
| | - Rebecca S Woodruff
- Departments of Surgery and Pharmacology and Cancer Biology, Duke University Medical Center , Durham, North Carolina
| | - Bruce A Sullenger
- Departments of Surgery and Pharmacology and Cancer Biology, Duke University Medical Center , Durham, North Carolina
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