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Beesley NJ, Cwiklinski K, Allen K, Hoyle RC, Spithill TW, La Course EJ, Williams DJL, Paterson S, Hodgkinson JE. A major locus confers triclabendazole resistance in Fasciola hepatica and shows dominant inheritance. PLoS Pathog 2023; 19:e1011081. [PMID: 36701396 PMCID: PMC9904461 DOI: 10.1371/journal.ppat.1011081] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 02/07/2023] [Accepted: 12/22/2022] [Indexed: 01/27/2023] Open
Abstract
Fasciola hepatica infection is responsible for substantial economic losses in livestock worldwide and poses a threat to human health in endemic areas. The mainstay of control in livestock and the only drug licenced for use in humans is triclabendazole (TCBZ). TCBZ resistance has been reported on every continent and threatens effective control of fasciolosis in many parts of the world. To date, understanding the genetic mechanisms underlying TCBZ resistance has been limited to studies of candidate genes, based on assumptions of their role in drug action. Taking an alternative approach, we combined a genetic cross with whole-genome sequencing to localise a ~3.2Mbp locus within the 1.2Gbp F. hepatica genome that confers TCBZ resistance. We validated this locus independently using bulk segregant analysis of F. hepatica populations and showed that it is the target of drug selection in the field. We genotyped individual parasites and tracked segregation and reassortment of SNPs to show that TCBZ resistance exhibits Mendelian inheritance and is conferred by a dominant allele. We defined gene content within this locus to pinpoint genes involved in membrane transport, (e.g. ATP-binding cassette family B, ABCB1), transmembrane signalling and signal transduction (e.g. GTP-Ras-adenylyl cyclase and EGF-like protein), DNA/RNA binding and transcriptional regulation (e.g. SANT/Myb-like DNA-binding domain protein) and drug storage and sequestration (e.g. fatty acid binding protein, FABP) as prime candidates for conferring TCBZ resistance. This study constitutes the first experimental cross and genome-wide approach for any heritable trait in F. hepatica and is key to understanding the evolution of drug resistance in Fasciola spp. to inform deployment of efficacious anthelmintic treatments in the field.
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Affiliation(s)
- Nicola J. Beesley
- Veterinary Parasitology, Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
- * E-mail: (NJB); (JEH)
| | - Krystyna Cwiklinski
- Veterinary Parasitology, Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Katherine Allen
- Veterinary Parasitology, Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Rebecca C. Hoyle
- Veterinary Parasitology, Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Terry W. Spithill
- Department of Animal, Plant and Soil Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Australia
| | | | - Diana J. L. Williams
- Veterinary Parasitology, Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Steve Paterson
- Centre for Genomic Research, Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Jane E. Hodgkinson
- Veterinary Parasitology, Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
- * E-mail: (NJB); (JEH)
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Fernandez-Baca MV, Hoban C, Ore RA, Ortiz P, Choi YJ, Murga-Moreno C, Mitreva M, Cabada MM. The Differences in the Susceptibility Patterns to Triclabendazole Sulfoxide in Field Isolates of Fasciola hepatica Are Associated with Geographic, Seasonal, and Morphometric Variations. Pathogens 2022; 11:pathogens11060625. [PMID: 35745479 PMCID: PMC9227168 DOI: 10.3390/pathogens11060625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/14/2022] [Accepted: 05/19/2022] [Indexed: 02/01/2023] Open
Abstract
Triclabendazole (TCBZ) resistance is an emerging problem in fascioliasis that is not well understood. Studies including small numbers of parasites fail to capture the complexity of susceptibility variations between and within Fasciolahepatica populations. As the first step to studying the complex resistant phenotype−genotype associations, we characterized a large sample of adult F. hepatica with diverging TCBZ susceptibility. We collected parasites from naturally infected livestock slaughtered in the Cusco and Cajamarca regions of Peru. These parasites were exposed to TCBZ sulfoxide (TCBZ.SO) in vitro to determine their susceptibility. We used a motility score to determine the parasite’s viability. We titrated drug concentrations and times to detect 20% non-viable (susceptible conditions) or 80% non-viable (resistant conditions) parasites. We exposed 3348 fully motile parasites to susceptible (n = 1565) or resistant (n = 1783) conditions. Three hundred and forty-one (21.8%) were classified as susceptible and 462 (25.9%) were classified as resistant. More resistant parasites were found in Cusco than in Cajamarca (p < 0.001). Resistant parasites varied by slaughterhouse (p < 0.001), month of the year (p = 0.008), fluke length (p = 0.016), and year of collection (p < 0.001). The in vitro susceptibility to TCBZ.SO in wildtype F. hepatica was associated with geography, season, and morphometry.
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Affiliation(s)
- Martha V. Fernandez-Baca
- Sede Cusco, Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia, Calle Jose Carlos Mariategui J-6, Wanchaq, Cusco 08002, Peru; (M.V.F.-B.); (R.A.O.)
| | - Cristian Hoban
- Laboratorio de Inmunología, Facultad de Ciencias Veterinarias, Universidad Nacional de Cajamarca, Avenida Atahualpa 1050, Cajamarca 06001, Peru; (C.H.); (P.O.); (C.M.-M.)
| | - Rodrigo A. Ore
- Sede Cusco, Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia, Calle Jose Carlos Mariategui J-6, Wanchaq, Cusco 08002, Peru; (M.V.F.-B.); (R.A.O.)
| | - Pedro Ortiz
- Laboratorio de Inmunología, Facultad de Ciencias Veterinarias, Universidad Nacional de Cajamarca, Avenida Atahualpa 1050, Cajamarca 06001, Peru; (C.H.); (P.O.); (C.M.-M.)
| | - Young-Jun Choi
- Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, 4523 Clayton Avenue, MSC 8051-0043-15, St. Louis, MO 63110, USA;
| | - César Murga-Moreno
- Laboratorio de Inmunología, Facultad de Ciencias Veterinarias, Universidad Nacional de Cajamarca, Avenida Atahualpa 1050, Cajamarca 06001, Peru; (C.H.); (P.O.); (C.M.-M.)
| | - Makedonka Mitreva
- Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, 4523 Clayton Avenue, MSC 8051-0043-15, St. Louis, MO 63110, USA;
- McDonnell Genome Institute, Washington University, 4444 Forest Park Avenue, St. Louis, MO 63108, USA
- Correspondence: (M.M.); (M.M.C.)
| | - Miguel M. Cabada
- Sede Cusco, Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia, Calle Jose Carlos Mariategui J-6, Wanchaq, Cusco 08002, Peru; (M.V.F.-B.); (R.A.O.)
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Correspondence: (M.M.); (M.M.C.)
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3
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Fairweather I, Brennan GP, Hanna REB, Robinson MW, Skuce PJ. Drug resistance in liver flukes. Int J Parasitol Drugs Drug Resist 2020; 12:39-59. [PMID: 32179499 PMCID: PMC7078123 DOI: 10.1016/j.ijpddr.2019.11.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023]
Abstract
Liver flukes include Fasciola hepatica, Fasciola gigantica, Clonorchis sinensis, Opisthorchis spp., Fascioloides magna, Gigantocotyle explanatum and Dicrocoelium spp. The two main species, F. hepatica and F. gigantica, are major parasites of livestock and infections result in huge economic losses. As with C. sinensis, Opisthorchis spp. and Dicrocoelium spp., they affect millions of people worldwide, causing severe health problems. Collectively, the group is referred to as the Food-Borne Trematodes and their true significance is now being more widely recognised. However, reports of resistance to triclabendazole (TCBZ), the most widely used anti-Fasciola drug, and to other current drugs are increasing. This is a worrying scenario. In this review, progress in understanding the mechanism(s) of resistance to TCBZ is discussed, focusing on tubulin mutations, altered drug uptake and changes in drug metabolism. There is much interest in the development of new drugs and drug combinations, the re-purposing of non-flukicidal drugs, and the development of new drug formulations and delivery systems; all this work will be reviewed. Sound farm management practices also need to be put in place, with effective treatment programmes, so that drugs can be used wisely and their efficacy conserved as much as is possible. This depends on reliable advice being given by veterinarians and other advisors. Accurate diagnosis and identification of drug-resistant fluke populations is central to effective control: to determine the actual extent of the problem and to determine how well or otherwise a treatment has worked; for research on establishing the mechanism of resistance (and identifying molecular markers of resistance); for informing treatment options; and for testing the efficacy of new drug candidates. Several diagnostic methods are available, but there are no recommended guidelines or standardised protocols in place and this is an issue that needs to be addressed.
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Affiliation(s)
- I Fairweather
- School of Biological Sciences, The Queen's University of Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK.
| | - G P Brennan
- School of Biological Sciences, The Queen's University of Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK
| | - R E B Hanna
- Veterinary Sciences Division, Agri-Food and Biosciences Institute (AFBI), Stormont, Belfast, BT4 3SD, UK
| | - M W Robinson
- School of Biological Sciences, The Queen's University of Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK
| | - P J Skuce
- Disease Control, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Edinburgh, EH26 0PZ, UK
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Increased action of triclabendazole (TCBZ) in vitro against a TCBZ-resistant isolate of Fasciola hepatica following its co-incubation with the P-glycoprotein inhibitor, R(+)-verapamil. Exp Parasitol 2013; 135:642-53. [DOI: 10.1016/j.exppara.2013.09.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/09/2013] [Accepted: 09/22/2013] [Indexed: 01/31/2023]
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5
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Immunization with recombinant leucine aminopeptidase showed protection against Fasciola gigantica in mice. Parasitol Res 2013; 112:3653-9. [DOI: 10.1007/s00436-013-3553-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 07/22/2013] [Indexed: 02/02/2023]
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6
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Effect of the P-glycoprotein inhibitor, R(+)-verapamil on the drug susceptibility of a triclabendazole-resistant isolate of Fasciola hepatica. Vet Parasitol 2013; 195:72-86. [DOI: 10.1016/j.vetpar.2013.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 02/27/2013] [Accepted: 03/07/2013] [Indexed: 11/18/2022]
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Increased susceptibility of a triclabendazole (TCBZ)-resistant isolate of Fasciola hepatica to TCBZ following co-incubation in vitro with the P-glycoprotein inhibitor, R(+)-verapamil. Parasitology 2013; 140:1287-303. [PMID: 23756576 DOI: 10.1017/s0031182013000759] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A study was carried out to investigate whether the action of triclabendazole sulphoxide (TCBZ.SO) against the liver fluke, Fasciola hepatica is altered by inhibition of P-glycoprotein (Pgp)-linked drug efflux pumps. The Oberon TCBZ-resistant and Cullompton TCBZ-susceptible fluke isolates were used for this in vitro study and the Pgp inhibitor selected was R(+)-verapamil [R(+)-VPL]. For experiments with the Oberon isolate, flukes were incubated for 24 h with either R(+)-VPL (1×10-4 m) on its own, TCBZ.SO (15 μg mL-1) alone, a combination of R(+)-VPL (1×10-4 m) plus TCBZ.SO (15 μg mL-1), TCBZ.SO (50 μg mL-1) on its own, or a combination of TCBZ.SO (50 μg mL-1) plus R(+)-VPL (1×10-4 m). They were also incubated in TCBZ.SO (50 μg mL-1) alone or in combination with R(+)-VPL (1×10-4 m) until they became inactive; and in TCBZ.SO (50 μg mL-1) alone for a time to match that of the combination inactivity time. Flukes from the Cullompton isolate were treated with either TCBZ.SO (50 μg mL-1) alone or in combination with R(+)-VPL (1×10-4 m) until they became inactive, or with TCBZ.SO (50 μg mL-1) alone time-matched to the combination inactivity time. Morphological changes resulting from drug treatment and following Pgp inhibition were assessed by means of scanning electron microscopy. Incubation in R(+)-VPL alone had a minimal effect on either isolate. TCBZ.SO treatment had a relatively greater impact on the TCBZ-susceptible Cullompton isolate. When R(+)-VPL was combined with TCBZ.SO in the incubation medium, however, the surface disruption to both isolates was more severe than that seen after TCBZ.SO treatment alone; also, the time taken to reach inactivity was shorter. More significantly, though, the potentiation of drug activity was greater in the Oberon isolate; also, it was more distinct at the higher concentration of TCBZ.SO. So, the Oberon isolate appears to be particularly sensitive to efflux pump inhibition. The results of this study suggest that enhanced drug efflux in the Oberon isolate may be involved in the mechanism of resistance to TCBZ.
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Identification of putative markers of triclabendazole resistance by a genome-wide analysis of genetically recombinant Fasciola hepatica. Parasitology 2013; 140:1523-33. [PMID: 23721579 DOI: 10.1017/s0031182013000528] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Despite years of investigation into triclabendazole (TCBZ) resistance in Fasciola hepatica, the genetic mechanisms responsible remain unknown. Extensive analysis of multiple triclabendazole-susceptible and -resistant isolates using a combination of experimental in vivo and in vitro approaches has been carried out, yet few, if any, genes have been demonstrated experimentally to be associated with resistance phenotypes in the field. In this review we summarize the current understanding of TCBZ resistance from the approaches employed to date. We report the current genomic and genetic resources for F. hepatica that are available to facilitate novel functional genomics and genetic experiments for this parasite in the future. Finally, we describe our own non-biased approach to mapping the major genetic loci involved in conferring TCBZ resistance in F. hepatica.
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Vokřál I, Jirásko R, Stuchlíková L, Bártíková H, Szotáková B, Lamka J, Várady M, Skálová L. Biotransformation of albendazole and activities of selected detoxification enzymes in Haemonchus contortus strains susceptible and resistant to anthelmintics. Vet Parasitol 2013; 196:373-81. [PMID: 23587403 DOI: 10.1016/j.vetpar.2013.03.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/05/2013] [Accepted: 03/15/2013] [Indexed: 11/27/2022]
Abstract
The increased activity of drug-metabolizing enzymes can protect helminths against the toxic effect of anthelmintics. The aim of this study was to compare the metabolism of the anthelmintic drug albendazole (ABZ) and the activities of selected biotransformation and antioxidant enzymes in three different strains of Haemonchus contortus: the ISE strain (susceptible to common anthelmintics), the BR strain (resistant to benzimidazole anthelmintics) and the WR strain (multi-resistant). H. contortus adults were collected from the abomasum of experimentally infected lambs. In vitro (subcellular fractions of H. contortus homogenate) as well as ex vivo (living nematodes cultivated in flasks with medium) experiments were performed. HPLC with spectrofluorimetric and mass-spectrometric detection was used in the analysis of ABZ metabolites. The in vitro activities of oxidation/antioxidation and conjugation enzymes toward model substrates were also assayed. The in vitro data showed significant differences between the susceptible (ISE) and resistant (BR, WR) strains regarding the activities of peroxidases, catalase and UDP-glucosyltransferases. S-oxidation of ABZ was significantly lower in BR than in the ISE strain. Ex vivo, four ABZ metabolites were identified: ABZ sulphoxide and three ABZ glucosides. In the resistant strains BR and WR, the ex vivo formation of all ABZ glucosides was significantly higher than in the susceptible ISE strain. The altered activities of certain detoxifying enzymes might partly protect the parasites against the toxic effect of the drugs as well as contribute to drug-resistance in these parasites.
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Affiliation(s)
- Ivan Vokřál
- Department of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Czech Republic
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The metabolic fate of ivermectin in host (Ovis aries) and parasite (Haemonchus contortus). Parasitology 2012; 140:361-7. [DOI: 10.1017/s0031182012001680] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYIvermectin (IVE), one of the most important anthelmintics, is often used in the treatment of haemonchosis in ruminants. The objective of our work was (1) to find and identify phase I and II metabolites of IVE formed by the Barber's pole worm (Haemonchus contortus), and (2) to compare IVE metabolites in helminths with IVE biotransformation in sheep (Ovis aries) as host species. Ultrahigh-performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) was used for this purpose. During in vitro incubations, microsomes (from adult worms or from ovine liver) and a primary culture of ovine hepatocytes were incubated with IVE. In the ex vivo study, living H. contortus adults were incubated in the presence of 1 μM IVE for 24 h. The results showed that the H. contortus enzymatic system is not able to metabolize IVE. On the other hand, 7 different phase I as well as 9 phase II IVE metabolites were detected in ovine samples using UHPLC/MS/MS analyses. Most of these metabolites have not been described before. Haemonchus contortus is not able to deactivate IVE through biotransformation; therefore, biotransformation does not contribute to the development of IVE-resistance in the Barber's pole worm.
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The metabolism of flubendazole and the activities of selected biotransformation enzymes in Haemonchus contortus strains susceptible and resistant to anthelmintics. Parasitology 2012; 139:1309-16. [PMID: 22717022 DOI: 10.1017/s0031182012000595] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Haemonchus contortus is one of the most pathogenic parasites of small ruminants (e.g. sheep and goat). The treatment of haemonchosis is complicated because of recurrent resistance of H. contortus to common anthelmintics. The aim of this study was to compare the metabolism of the anthelmintic drug flubendazole (FLU) and the activities of selected biotransformation enzymes towards model xenobiotics in 4 different strains of H. contortus: the ISE strain (susceptible to common anthelmintics), ISE-S (resistant to ivermectin), the BR strain (resistant to benzimidazole anthelmintics) and the WR strain (resistant to all common anthelmintics). H. contortus adults were collected from the abomasums from experimentally infected lambs. The in vitro as well as ex vivo experiments were performed and analysed using HPLC with spectrofluorimetric and mass-spectrometric detection. In all H. contortus strains, 4 different FLU metabolites were detected: FLU with a reduced carbonyl group (FLU-R), glucose conjugate of FLU-R and 2 glucose conjugates of FLU. In the resistant strains, the ex vivo formation of all FLU metabolites was significantly higher than in the susceptible ISE strain. The multi-resistant WR strain formed approximately 5 times more conjugates of FLU than the susceptible ISE strain. The in vitro data also showed significant differences in FLU metabolism, in the activities of UDP-glucosyltransferase and several carbonyl-reducing enzymes between the susceptible and resistant H. contortus strains. The altered activities of certain detoxifying enzymes might protect the parasites against the toxic effect of the drugs as well as contribute to drug-resistance in these parasites.
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Fairweather I, McShane D, Shaw L, Ellison S, O’Hagan N, York E, Trudgett A, Brennan G. Development of an egg hatch assay for the diagnosis of triclabendazole resistance in Fasciola hepatica: Proof of concept. Vet Parasitol 2012; 183:249-59. [DOI: 10.1016/j.vetpar.2011.07.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/26/2011] [Accepted: 07/08/2011] [Indexed: 10/17/2022]
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Devine C, Brennan G, Lanusse C, Alvarez L, Trudgett A, Hoey E, Fairweather I. Potentiation of triclabendazole action in vivo against a triclabendazole-resistant isolate of Fasciola hepatica following its co-administration with the metabolic inhibitor, ketoconazole. Vet Parasitol 2012; 184:37-47. [DOI: 10.1016/j.vetpar.2011.08.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/22/2011] [Accepted: 08/01/2011] [Indexed: 11/25/2022]
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14
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Erratum to: inhibition of triclabendazole metabolism in vitro by ketoconazole increases disruption to the tegument of a triclabendazole-resistant isolate of Fasciola hepatica. Parasitol Res 2011; 109:1209-23. [PMID: 21858480 DOI: 10.1007/s00436-011-2554-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 02/10/2011] [Indexed: 10/17/2022]
Abstract
A study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by inhibition of drug metabolism. The cytochrome P450 (CYP 450) enzyme pathway was inhibited using ketoconazole (KTZ) to see whether a TCBZ-resistant isolate could be made more sensitive to TCBZ action. The Oberon TCBZ-resistant and Cullompton TCBZ-susceptible isolates were used for these experiments. The CYP 450 system was inhibited by a 2-h pre-incubation in ketoconazole (40 μM), then incubated for a further 22 h in NCTC medium containing either KTZ, KTZ + nicotinamide adenine dinucleotide phosphate (NADPH) (1 nM), KTZ + NADPH + TCBZ (15 μg/ml), or KTZ + NADPH + triclabendazole sulphoxide (TCBZ.SO; 15 μg/ml). Changes to fluke ultrastructure following drug treatment and metabolic inhibition were assessed using transmission electron microscopy. After treatment with either TCBZ or TCBZ.SO on their own, there was greater disruption to the TCBZ-susceptible than TCBZ-resistant isolate. However, co-incubation with KTZ + TCBZ, but more particularly KTZ + TCBZ.SO, led to more severe changes to the TCBZ-resistant isolate than with each drug on its own: for example, there was severe swelling of the basal infolds and their associated mucopolysaccharide masses, accompanied by an accumulation of secretory bodies just below the apex. Golgi complexes were greatly reduced or absent in the tegumental cells and the synthesis, production, and transport of secretory bodies were badly disrupted. With the TCBZ-susceptible Cullompton isolate, there was limited potentiation of drug action. The results support the concept of altered drug metabolism in TCBZ-resistant flukes and this process may play a role in the development of drug resistance.
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15
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Fairweather I. Reducing the future threat from (liver) fluke: realistic prospect or quixotic fantasy? Vet Parasitol 2011; 180:133-43. [DOI: 10.1016/j.vetpar.2011.05.034] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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16
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Inhibition of triclabendazole metabolism in vitro by ketoconazole increases disruption to the tegument of a triclabendazole-resistant isolate of Fasciola hepatica. Parasitol Res 2011; 109:981-95. [PMID: 21442257 DOI: 10.1007/s00436-011-2304-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 02/10/2011] [Indexed: 10/18/2022]
Abstract
A study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by inhibition of drug metabolism. The cytochrome P450 (CYP 450) enzyme pathway was inhibited using ketoconazole (KTZ) to see whether a TCBZ-resistant isolate could be made more sensitive to TCBZ action. The Oberon TCBZ-resistant and Cullompton TCBZ-susceptible isolates were used for these experiments. The CYP 450 system was inhibited by a 2-h pre-incubation in ketoconazole (40 μM), then incubated for a further 22 h in NCTC medium containing either KTZ, KTZ + nicotinamide adenine dinucleotide phosphate (NADPH) (1 nM), KTZ + NADPH + TCBZ (15 μg/ml), or KTZ + NADPH + triclabendazole sulphoxide (TCBZ.SO; 15 μg/ml). Changes to fluke ultrastructure following drug treatment and metabolic inhibition were assessed using transmission electron microscopy. After treatment with either TCBZ or TCBZ.SO on their own, there was greater disruption to the TCBZ-susceptible than TCBZ-resistant isolate. However, co-incubation with KTZ + TCBZ, but more particularly KTZ + TCBZ.SO, led to more severe changes to the TCBZ-resistant isolate than with each drug on its own: in the syncytium, for example, there was severe swelling of the basal infolds and their associated mucopolysaccharide masses, accompanied by an accumulation of secretory bodies just below the apex. Golgi complexes were greatly reduced or absent in the tegumental cells and the synthesis, production, and transport of secretory bodies were badly disrupted. With the TCBZ-susceptible Cullompton isolate, there was limited potentiation of drug action. The results support the concept of altered drug metabolism in TCBZ-resistant flukes and this process may play a role in the development of drug resistance.
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Fairweather I. Liver fluke isolates: a question of provenance. Vet Parasitol 2010; 176:1-8. [PMID: 21227593 DOI: 10.1016/j.vetpar.2010.12.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 12/03/2010] [Accepted: 12/09/2010] [Indexed: 10/18/2022]
Abstract
A survey of literature on experimental infections with the liver fluke, Fasciola hepatica published between 2005 and 2009 has revealed a general lack of information on where fluke material (i.e. metacercariae) was sourced from. Even less information was given on the drug status of the fluke isolate used, which is a particular concern for those studies that involved anthelmintics. In these two respects, information on the liver fluke lags far behind that for nematodes, where such information is given almost as a matter of course. Of additional concern is that, at times, information about the source and drug history of fluke isolates was incorrect. The overall aim of the review is to demonstrate why it is important to provide as much information as possible on what fluke material is being used. It also attempts to correct some of the errors in the literature and gather together what information is available about the provenance of those isolates that have been used in recent experimental studies.
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Affiliation(s)
- I Fairweather
- Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, Belfast, UK.
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Devine C, Brennan GP, Lanusse CE, Alvarez LI, Trudgett A, Hoey E, Fairweather I. Enhancement of triclabendazole action in vivo against a triclabendazole-resistant isolate of Fasciola hepatica by co-treatment with ketoconazole. Vet Parasitol 2010; 177:305-15. [PMID: 21208747 DOI: 10.1016/j.vetpar.2010.12.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 11/26/2010] [Accepted: 12/06/2010] [Indexed: 10/18/2022]
Abstract
An in vivo study in the laboratory rat model was carried out to monitor morphological changes in adult Fasciola hepatica over a 4-day period resulting from combination treatment of triclabendazole (TCBZ) and the metabolic inhibitor, ketoconazole (KTZ). Rats were infected with the TCBZ-resistant Oberon isolate of F. hepatica and divided into 3 groups at 12 weeks post-infection. The first group was dosed orally with TCBZ at a dosage of 10mg/kg and KTZ at a dosage of 10mg/kg. Flukes were recovered at 24, 48, 72 and 96 h post-treatment (p.t.). A second group of rats was treated with TCBZ alone (10mg/kg) and sacrificed at 96 h p.t. The third group acted as untreated controls. Surface changes were monitored by scanning electron microscopy (SEM). In flukes from the TCBZ+KTZ-treated group, the results showed a progressive and time-dependent increase in the level of disruption to the tegumental syncytium. Swelling, furrowing, blebbing and sloughing of the syncytium increased with time p.t. Another feature seen was a thick layer of tegumental shedding in some fluke samples at different times p.t. By comparison, flukes treated with TCBZ alone remained unaffected. The results demonstrated that the Oberon isolate is only sensitive to drug action in the presence of ketoconazole, indicating that combining triclabendazole with a metabolic inhibitor could be used to preserve the effectiveness of the drug against TCBZ-resistant populations of F. hepatica.
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Affiliation(s)
- C Devine
- Parasite Therapeutics Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, United Kingdom
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Piperonyl butoxide enhances triclabendazole action against triclabendazole-resistant Fasciola hepatica. Parasitology 2010; 138:224-36. [PMID: 20946692 DOI: 10.1017/s0031182010001125] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A study has been carried out to determine whether the action of triclabendazole (TCBZ) against the liver fluke, Fasciola hepatica is altered by inhibition of the cytochrome P450 (CYP 450)-mediated drug metabolism pathway. The Oberon TCBZ-resistant and Cullompton TCBZ-susceptible fluke isolates were used for these experiments, the basic design of which is given in the paper by Devine et al. (2010a). Piperonyl butoxide (PB) was the CYP P450 inhibitor used. Morphological changes resulting from drug treatment and following metabolic inhibition were assessed by means of transmission electron microscopy. After treatment with either TCBZ or TCBZ.SO on their own, there was greater disruption to the TCBZ-susceptible than TCBZ-resistant isolate. However, co-incubation with PB+TCBZ, but more particularly PB+TCBZ.SO, led to greater changes to the TCBZ-resistant isolate than with each drug on its own, with blebbing of the apical plasma membrane, severe swelling of the basal infolds and their associated mucopolysaccharide masses in the syncytium and flooding in the internal tissues. Golgi complexes were greatly reduced or absent in the tegumental cells and the synthesis and production of secretory bodies were badly disrupted. The mitochondria were swollen throughout the tegumental system and the somatic muscle blocks were disrupted. With the TCBZ-susceptible Cullompton isolate, there was a limited increase in drug action following co-incubation with PB. The results provide evidence that the condition of a TCBZ-resistant fluke can be altered by inhibition of drug metabolism. Moreover, they support the concept that altered drug metabolism contributes to the mechanism of resistance to TCBZ.
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Enhancement of the drug susceptibility of a triclabendazole-resistant isolate of Fasciola hepatica using the metabolic inhibitor ketoconazole. Parasitol Res 2010; 107:337-53. [PMID: 20512589 DOI: 10.1007/s00436-010-1866-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 03/29/2010] [Indexed: 10/19/2022]
Abstract
A study has been carried out to investigate whether the action of triclabendazole (TCBZ) is altered by using the metabolic inhibitor, ketoconazole (KTZ) to inhibit the cytochrome P450 (CYP 450) system within Fasciola hepatica. The Oberon TCBZ-resistant and Cullompton TCBZ-susceptible isolates were used for these experiments. The CYP 450 enzyme system was inhibited by a 2 h pre-incubation in KTZ (40 microM). Flukes were then incubated for a further 22 h in NCTC medium containing either KTZ; KTZ + nicotinamide adenine dinucleotide phosphate (NADPH; 1 nM); KTZ + NADPH + TCBZ (15 microg/ml); or KTZ + NADPH + triclabendazole sulphoxide (TCBZ.SO;15 microg/ml). Morphological changes resulting from drug treatment and following metabolic inhibition were assessed using scanning electron microscopy. After treatment with either TCBZ or TCBZ.SO alone, there was greater disruption to the TCBZ-susceptible isolate than the TCBZ-resistant isolate. However, co-incubation with KTZ and TCBZ/TCBZ.SO led to more severe surface changes to the TCBZ-resistant isolate than with each drug on its own, with greater swelling and blebbing of the tegument and even the loss of the apical plasma membrane in places. With the Cullompton isolate, there was limited potentiation of drug action in combination with KTZ, and only with TCBZ.SO. The results support the concept of altered drug metabolism within TCBZ-resistant isolates and indicate that this process may play a role in the development of drug resistance.
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