Fasciola hepatica : tegumental surface alterations following treatment in vivo and in vitro with nitroxynil (Trodax)

Fasciola spp. liver fluke have significant impacts in veterinary and human medicine. The absence of a vaccine and increasing anthelmintic resistance threaten sustainable control and underscore the need for novel flukicides. Functional genomic approaches underpinned by in vitro culture of juvenile Fasciola hepatica facilitate control target validation in the most pathogenic life stage. Comparative transcriptomics of in vitro and in vivo maintained 21 day old F. hepatica finds that 86% of genes are expressed at similar levels across maintenance treatments suggesting commonality in core biological functioning within these juveniles. Phenotypic comparisons revealed higher cell proliferation and growth rates in the in vivo juveniles compared to their in vitro counterparts. These phenotypic differences were consistent with the upregulation of neoblast-like stem cell and cell-cycle associated genes in in vivo maintained worms. The more rapid growth/development of in vivo juveniles was further evidenced by a switch in cathepsin protease expression profiles, dominated by cathepsin B in in vitro juveniles and then by cathepsin L in in vivo juveniles. Coincident with more rapid growth/development was the marked downregulation of both classical and peptidergic neuronal signalling components in in vivo maintained juveniles, supporting a role for the nervous system in regulating liver fluke growth and development. Differences in the miRNA complements of in vivo and in vitro juveniles identified 31 differentially expressed miRNAs, notably fhe-let-7a-5p , fhe-mir-124-3p and, miRNAs predicted to target Wnt-signalling, supporting a key role for miRNAs in driving the growth/developmental differences in the in vitro and in vivo maintained juvenile liver fluke. Widespread differences in the expression of neuronal genes in juvenile fluke grown in vitro and in vivo expose significant interplay between neuronal signalling and the rate of growth/development, encouraging consideration of neuronal targets in efforts to dysregulate growth/development for parasite control.

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Tegumental surface changes in juvenile Fasciola hepatica in response to treatment in vivo with triclabendazole

Veterinary Parasitology ◽

10.1016/j.vetpar.2008.04.011 ◽

2008 ◽

Vol 155 (1-2) ◽

pp. 49-58 ◽

Cited By ~ 33

Author(s):

L. Halferty ◽

G.P. Brennan ◽

R.E.B. Hanna ◽

H.W. Edgar ◽

M.M. Meaney ◽

...

Keyword(s):

Fasciola Hepatica ◽

Response To Treatment ◽

Tegumental Surface ◽

Surface Changes

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In vitro and in vivo trematode models for chemotherapeutic studies

Parasitology ◽

10.1017/s0031182009991739 ◽

2009 ◽

Vol 137 (3) ◽

pp. 589-603 ◽

Cited By ~ 100

Author(s):

J. KEISER

Keyword(s):

Liver Fluke ◽

Fasciola Hepatica ◽

State Of The Art ◽

Parasitic Diseases ◽

Current State ◽

Food Borne ◽

Essential Components ◽

Discovery Pipeline

SUMMARYSchistosomiasis and food-borne trematodiases are chronic parasitic diseases affecting millions of people mostly in the developing world. Additional drugs should be developed as only few drugs are available for treatment and drug resistance might emerge. In vitro and in vivo whole parasite screens represent essential components of the trematodicidal drug discovery cascade. This review describes the current state-of-the-art of in vitro and in vivo screening systems of the blood fluke Schistosoma mansoni, the liver fluke Fasciola hepatica and the intestinal fluke Echinostoma caproni. Examples of in vitro and in vivo evaluation of compounds for activity are presented. To boost the discovery pipeline for these diseases there is a need to develop validated, robust high-throughput in vitro systems with simple readouts.

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The anthelmintic activity of 1,10-phenanthroline, a metalloenzyme inhibitor

Indian Journal of Animal Research ◽

10.18805/ijar.b-3692 ◽

2019 ◽

Author(s):

S.M.A. Abidi ◽

Kavita Singh ◽

A. Rehman ◽

R. Ullah ◽

L. Rehman ◽

...

Keyword(s):

Enzyme Inhibitor ◽

Anthelmintic Activity ◽

In Vivo Studies ◽

Parasitic Helminths ◽

Tegumental Surface ◽

Biochemical Assays ◽

Direct Exposure ◽

Surface Changes

Paramphistomosis is a chronic, debilitating parasitic disease of livestock prevalent in the tropical and sub-tropical countries. Globally there is a heavy reliance on anthelmintics but concerns over drug resistance encourage the search for new leads. Metalloproteinases play a significant role in the biology and life cycle of parasitic helminths. The efficacy of metalloproteinase inhibitor, 1,10-Phenanthroline (1,10-phe) which is commonly used as a specific enzyme inhibitor in biochemical assays, was tested in vitro on Gigantocotyle explanatum tegument as a marker of anthelmintic action. The scanning electron microscopy revealed that the tegumental surface exhibited considerable changes in the worms treated with the metalloenzyme inhibitor, 1,10-phe. The untreated control worms appeared normal showing smooth tegumental surface with abundant dome shaped papillae in the anterior to mid region, while their density was less around the acetabulum which serves as a hold-fast organ helping the worms to remain attached in biliary passage. The 1,10-phe produced significant tegumental damage when the liver amphistomes were in vitro exposed to this compound at 12.5 µM concentration. The surface changes appeared in the form of edematous ridges with prominent furrows and erosion of the dome shaped papillae with rosette shaped deep lesions as a result of which deep parenchymatous tissues were exposed. The collapse of sensory bulbs as well as sloughing of tegument, particularly in the anterior-mid region was observed. The nature of damage could be comparable to various anthelmintics used in previous studies. To the best of our knowledge this is the first report of direct exposure of amphistome worms to zinc metallo-enzyme inhibitor, however, further in vivo studies are required to ascertain the anthelmintic efficacy of 1,10-phe.

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Fasciola hepatica: Tegumental alterations in adult flukes following in vitro and in vivo administration of artesunate and artemether

Experimental Parasitology ◽

10.1016/j.exppara.2007.08.007 ◽

2008 ◽

Vol 118 (2) ◽

pp. 228-237 ◽

Cited By ~ 47

Author(s):

Jennifer Keiser ◽

Gianni Morson

Keyword(s):

Fasciola Hepatica ◽

In Vivo Administration

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Repurposing of the Fasciolicide Triclabendazole to Treat Infections Caused by Staphylococcus spp. and Vancomycin-Resistant Enterococci

Microorganisms ◽

10.3390/microorganisms9081697 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1697

Author(s):

Hongfei Pi ◽

Abiodun D. Ogunniyi ◽

Bhumi Savaliya ◽

Hang Thi Nguyen ◽

Stephen W. Page ◽

...

Keyword(s):

Fasciola Hepatica ◽

Bacterial Pathogens ◽

Oral Treatment ◽

Polymyxin B ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Vancomycin Resistant Enterococci ◽

Vancomycin Resistant

One approach to combat the increasing incidence of multidrug-resistant (MDR) bacterial pathogens involves repurposing existing compounds with known safety and development pathways as new antibacterial classes with potentially novel mechanisms of action. Here, triclabendazole (TCBZ), a drug originally developed to treat Fasciola hepatica (liver fluke) in sheep and cattle, and later in humans, was evaluated as an antibacterial alone or in combination with sub-inhibitory concentrations of polymyxin B (PMB) against clinical isolates and reference strains of key Gram-positive and Gram-negative bacteria. We show for the first time that in vitro, TCBZ selectively kills methicillin-sensitive and methicillin-resistant Staphylococcus aureus and Staphylococcus pseudintermedius at a minimum inhibitory concentration (MIC) range of 2–4 µg/mL, and vancomycin-resistant enterococci at a MIC range of 4–8 µg/mL. TCBZ also inhibited key Gram-negative bacteria in the presence of sub-inhibitory concentrations of PMB, returning MIC90 values of 1 µg/mL for Escherichia coli, 8 µg/mL for Klebsiella pneumoniae, 2 µg/mL for Acinetobacter baumannii and 4 µg/mL for Pseudomonasaeruginosa. Interestingly, TCBZ was found to be bacteriostatic against intracellular S. aureus but bactericidal against intracellular S. pseudintermedius. Additionally, TCBZ’s favourable pharmacokinetic (PK) and pharmacodynamic (PD) profile was further explored by in vivo safety and efficacy studies using a bioluminescent mouse model of S. aureus sepsis. We show that repeated four-hourly oral treatment of mice with 50 mg/kg TCBZ after systemic S. aureus challenge resulted in a significant reduction in S. aureus populations in the blood to 18 h post-infection (compared to untreated mice) but did not clear the bacterial infection from the bloodstream, consistent with in vivo bacteriostatic activity. These results indicate that additional pharmaceutical development of TCBZ may enhance its PK/PD, allowing it to be an appropriate candidate for the treatment of serious MDR bacterial pathogens.

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Fasciola hepatica: Tegumental surface changes in adult and juvenile flukes following treatment in vitro with the sulphoxide metabolite of triclabendazole (Fasinex)

Zeitschrift für Parasitenkunde Parasitology Research ◽

10.1007/bf00932235 ◽

1993 ◽

Vol 79 (7) ◽

pp. 529-536 ◽

Cited By ~ 59

Author(s):

A. W. Stitt ◽

I. Fairweather

Keyword(s):

Fasciola Hepatica ◽

Tegumental Surface ◽

Surface Changes

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In Vivo and In Vitro Sensitivity of Fasciola hepatica to Triclabendazole Combined with Artesunate, Artemether, or OZ78

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00828-10 ◽

2010 ◽

Vol 54 (11) ◽

pp. 4596-4604 ◽

Cited By ~ 25

Author(s):

Urs Duthaler ◽

Thomas A. Smith ◽

Jennifer Keiser

Keyword(s):

Negative Binomial ◽

Fasciola Hepatica ◽

Single Agent ◽

Treatment Strategies ◽

Drug Combinations ◽

Antagonistic Effects ◽

Experimental Drugs ◽

New Treatment

ABSTRACT Triclabendazole resistance is continually documented from livestock, and hence new treatment strategies for Fasciola hepatica infections are needed. We investigated the effect of triclabendazole combined with artesunate, artemether, or OZ78 compared to that of monotherapy against adult and juvenile F. hepatica in rats. In vitro experiments with triclabendazole and its sulfoxide and sulfone metabolites, each in combination with the peroxides, complemented our study. F. hepatica-infected rats were subjected to single drugs or drug combinations 3 to 4 weeks (juvenile flukes) and >8 weeks (adult flukes) postinfection. Negative binomial regressions of worm and egg counts were used to analyze dose-response relationships and whether the effects of drug combinations were synergistic or antagonistic. The in vitro assays were evaluated by means of viability scales based on fluke motility. Fifty percent effective dose values of 113.0, 77.7, 22.9, and 2.7 mg/kg of body weight were calculated for monotherapy with artesunate, artemether, OZ78, and triclabendazole, respectively, against adult F. hepatica. Likelihood ratio tests revealed synergistic interactions (P < 0.05) of combinations of triclabendazole (2.5 mg/kg) plus artesunate or artemether on adult worm burden. Antagonistic effects on the adult burden and egg output were observed when a lower triclabendazole dose (1.25 mg/kg) was combined with the artemisinins. No significant interactions (P = 0.07) were observed for OZ78 and triclabendazole combinations and between the triclabendazole effect and the effects of the other partner drugs on juvenile worms. Our in vitro studies of adult worms agreed with the in vivo results, while the in vitro analysis of juvenile worms revealed greater interactions than observed in vivo. In conclusion, single-agent triclabendazole demonstrated a more potent in vivo and in vitro fasciocidal activity than the experimental drugs artesunate, artemether, and OZ78. When combined, synergistic but also antagonistic effects depending on the doses administered were observed, which should be elucidated in more detail in future studies.

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