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Marriott AE, Casewell NR, Lilley E, Gutiérrez JM, Ainsworth S. Improving in vivo assays in snake venom and antivenom research: A community discussion. F1000Res 2024; 13:192. [PMID: 38708289 PMCID: PMC11066530 DOI: 10.12688/f1000research.148223.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/06/2024] [Indexed: 05/07/2024] Open
Abstract
On the 26 th January 2023, a free to attend, 'improving in vivo snake venom research: a community discussion' meeting was held virtually. This webinar brought together researchers from around the world to discuss current neutralisation of venom lethality mouse assays that are used globally to assess the efficacy of therapies for snakebite envenoming. The assay's strengths and weaknesses were highlighted, and we discussed what improvements could be made to refine and reduce animal testing, whilst supporting preclinical antivenom and drug discovery for snakebite envenoming. This report summarises the issues highlighted, the discussions held, with additional commentary on key perspectives provided by the authors.
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Affiliation(s)
- Amy E Marriott
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, England, L3 5RF, UK
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Nicholas R Casewell
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Elliot Lilley
- National Centre for the Replacement, Reduction and Refinement of Animals in Research, London, NW1 2BE, UK
| | - José-María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, 11501-2060, Costa Rica
| | - Stuart Ainsworth
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, England, L3 5RF, UK
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
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Patel RN, Clare RH, Ledsgaard L, Nys M, Kool J, Laustsen AH, Ulens C, Casewell NR. An in vitro assay to investigate venom neurotoxin activity on muscle-type nicotinic acetylcholine receptor activation and for the discovery of toxin-inhibitory molecules. Biochem Pharmacol 2023; 216:115758. [PMID: 37604290 PMCID: PMC10570928 DOI: 10.1016/j.bcp.2023.115758] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 08/23/2023]
Abstract
Snakebite envenoming is a neglected tropical disease that causes over 100,000 deaths annually. Envenomings result in variable pathologies, but systemic neurotoxicity is among the most serious and is currently only treated with difficult to access and variably efficacious commercial antivenoms. Venom-induced neurotoxicity is often caused by α-neurotoxins antagonising the muscle-type nicotinic acetylcholine receptor (nAChR), a ligand-gated ion channel. Discovery of therapeutics targeting α-neurotoxins is hampered by relying on binding assays that do not reveal restoration of receptor activity or more costly and/or lower throughput electrophysiology-based approaches. Here, we report the validation of a screening assay for nAChR activation using immortalised TE671 cells expressing the γ-subunit containing muscle-type nAChR and a fluorescent dye that reports changes in cell membrane potential. Assay validation using traditional nAChR agonists and antagonists, which either activate or block ion fluxes, was consistent with previous studies. We then characterised antagonism of the nAChR by a variety of elapid snake venoms that cause muscle paralysis in snakebite victims, before defining the toxin-inhibiting activities of commercial antivenoms, and new types of snakebite therapeutic candidates, namely monoclonal antibodies, decoy receptors, and small molecules. Our findings show robust evidence of assay uniformity across 96-well plates and highlight the amenability of this approach for the future discovery of new snakebite therapeutics via screening campaigns. The described assay therefore represents a useful first-step approach for identifying α-neurotoxins and their inhibitors in the context of snakebite envenoming, and it should provide wider value for studying modulators of nAChR activity from other sources.
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Affiliation(s)
- Rohit N Patel
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, L3 5QA, UK; Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, UK
| | - Rachel H Clare
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, L3 5QA, UK; Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, UK
| | - Line Ledsgaard
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Mieke Nys
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Belgium
| | - Jeroen Kool
- AIMMS Division of BioAnalytical Chemistry, Vrije Universiteit Amsterdam, Netherlands
| | - Andreas H Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Chris Ulens
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Belgium
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, L3 5QA, UK; Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, UK.
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Menzies SK, Litschka-Koen T, Edge RJ, Alsolaiss J, Crittenden E, Hall SR, Westhorpe A, Thomas B, Murray J, Shongwe N, Padidar S, Lalloo DG, Casewell NR, Pons J, Harrison RA. Two snakebite antivenoms have potential to reduce Eswatini's dependency upon a single, increasingly unavailable product: Results of preclinical efficacy testing. PLoS Negl Trop Dis 2022; 16:e0010496. [PMID: 36108067 PMCID: PMC9529146 DOI: 10.1371/journal.pntd.0010496] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 10/03/2022] [Accepted: 08/15/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Snakebite is a major public health concern in Eswatini, where treatment relies upon one antivenom-SAIMR Polyvalent. Although effective in treating snakebite, SAIMR Polyvalent is difficult to source outside its manufacturing country (South Africa) and is dauntingly expensive. We compared the preclinical venom-neutralising efficacy of two alternative antivenoms with that of SAIMR Polyvalent against the lethal and tissue-destructive effects of venoms from five species of medically important snakes using in vivo murine assays. The test antivenoms were 'Panafrican' manufactured by Instituto Clodomiro Picado and 'PANAF' manufactured by Premium Serums & Vaccines. PRINCIPAL FINDINGS In vivo murine preclinical studies identified both test antivenoms were equally or more effective than SAIMR Polyvalent at neutralising lethal and tissue-destructive effects of Naja mossambica venom. Both test antivenoms were less effective than SAIMR Polyvalent at neutralising the lethal effects of Bitis arietans, Dendroaspis polylepis, Hemachatus haemachatus and Naja annulifera venoms, but similarly effective at neutralising tissue damage induced by B. arietans and H. haemachatus venoms. In vitro immunological assays identified that the titres and toxin-specificities of immunoglobulins (iGs) in the test antivenoms were comparable to that of SAIMR Polyvalent. Plasma clotting disturbances by H. haemachatus and N. mossambica were neutralised by the test antivenoms, whereas SAIMR Polyvalent failed to neutralise this bioactivity of N. mossambica venom. B. arietans SVMP activity was equally reduced by all three antivenoms, and H. haemachatus and N. mossambica PLA2 activities were neutralised by all three antivenoms. CONCLUSIONS While both Panafrican and PANAF antivenoms exhibited promising preclinical efficacies, both were less poly-specifically effective than SAIMR Polyvalent in these murine assays. The efficacy of these antivenoms against the lethal and tissue-destructive effects of N. mossambica venom, the most common biting species in Eswatini, identify that Panafrican and PANAF antivenoms offer effective alternatives to SAIMR Polyvalent for the treatment of snakebite in Eswatini, and potentially for neighbouring countries.
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Affiliation(s)
- Stefanie K. Menzies
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Thea Litschka-Koen
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
| | - Rebecca J. Edge
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jaffer Alsolaiss
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Edouard Crittenden
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Steven R. Hall
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Adam Westhorpe
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Brent Thomas
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - James Murray
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
| | - Nondusimo Shongwe
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
| | - Sara Padidar
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
- Department of Biological Sciences, University of Eswatini, Kwaluseni, Eswatini
| | - David G. Lalloo
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jonathan Pons
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
| | - Robert A. Harrison
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Silva A, Hodgson WC, Tasoulis T, Isbister GK. Rodent Lethality Models Are Problematic for Evaluating Antivenoms for Human Envenoming. Front Pharmacol 2022; 13:830384. [PMID: 35185582 PMCID: PMC8850383 DOI: 10.3389/fphar.2022.830384] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/17/2022] [Indexed: 11/24/2022] Open
Affiliation(s)
- Anjana Silva
- Department of Parasitology, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Sri Lanka
- Monash Venom Group, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
- South Asian Clinical Toxicology Research Collaboration, University of Peradeniya, Peradeniya, Sri Lanka
| | - Wayne C. Hodgson
- Monash Venom Group, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
| | - Theo Tasoulis
- Clinical Toxicology Research Group, University of Newcastle, Newcastle, NSW, Australia
| | - Geoffrey K. Isbister
- South Asian Clinical Toxicology Research Collaboration, University of Peradeniya, Peradeniya, Sri Lanka
- Clinical Toxicology Research Group, University of Newcastle, Newcastle, NSW, Australia
- *Correspondence: Geoffrey K. Isbister,
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Gutiérrez JM, Vargas M, Segura Á, Herrera M, Villalta M, Solano G, Sánchez A, Herrera C, León G. In Vitro Tests for Assessing the Neutralizing Ability of Snake Antivenoms: Toward the 3Rs Principles. Front Immunol 2021; 11:617429. [PMID: 33505403 PMCID: PMC7829219 DOI: 10.3389/fimmu.2020.617429] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 11/23/2020] [Indexed: 12/24/2022] Open
Abstract
There is an urgent need to strengthen the implementation of the 3Rs principle (Replacement, Reduction and Refinement) in the use of experimental animals in toxinological research and in the assessment of the neutralizing efficacy of snake antivenoms. This is a challenging task owing to the inherent complexity of snake venoms. The state of the art on this topic is hereby reviewed, with emphasis on the studies in which a correlation has been observed between in vivo toxicity tests and in vitro surrogate assays, particularly in the study of lethal activity of venoms and its neutralization. Correlations have been described with some venoms-antivenoms when using: (a) enzyme immunoassays, (b) hemagglutination, (c) enzyme assays (proteinase, phospholipase A2), (d) in vitro coagulant effect on plasma, (e) cell culture assays for cytotoxicity, (f) functional assays for assessing neurotoxicity in vitro, (g) use of hens' eggs, and (h) antivenomics. Additionally, the routine introduction of analgesia in these assays and the design of more 'humane' protocols for the lethality test are being pursued. It is expected that the next years will witness a growing awareness of the relevance of the 3Rs principles in antivenom testing, and that new in vitro alternatives and more 'humane' experimental designs will emerge in this field.
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Affiliation(s)
| | - Mariángela Vargas
- Instituto Clodomiro Picado, Facultad de Microbiología, San José, Costa Rica
| | - Álvaro Segura
- Instituto Clodomiro Picado, Facultad de Microbiología, San José, Costa Rica
| | - María Herrera
- Instituto Clodomiro Picado, Facultad de Microbiología, San José, Costa Rica
| | - Mauren Villalta
- Instituto Clodomiro Picado, Facultad de Microbiología, San José, Costa Rica
| | - Gabriela Solano
- Instituto Clodomiro Picado, Facultad de Microbiología, San José, Costa Rica
| | - Andrés Sánchez
- Instituto Clodomiro Picado, Facultad de Microbiología, San José, Costa Rica
| | - Cristina Herrera
- Facultad de Farmacia, Universidad de Costa Rica, San José, Costa Rica
| | - Guillermo León
- Instituto Clodomiro Picado, Facultad de Microbiología, San José, Costa Rica
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