A murine model to assess anthelmintic resistance in Fasciola hepatica: preliminary study.

CEBALLOS, L; PRUZZO, CESAR; SANABRIA, R; ALVAREZ, L

Buenos Aires

Congreso; Drug Discovery for Neglected Diseases International Congress; 2018

IQUIMEFA - CONICET -Fac. Farmacia y Bioquímca, UBA

Introduction: Fasciola hepatica (Fh) infection produce important loss in livestock industry, and is also an increasing concern for human public health. Additionally, the spread of anthelmintic resistance (AR) lead to treatments failure2, whith a direct impact on humans? endemic regions3. Thus, advances in AR assessment are welcome, particularly those who allow a human´s extrapolation.Objective: the assessment of albendazole (ABZ) and triclabendazole (TCBZ) anthelmintic resistance in Fh, by a murine model. Materials y methods: 15 Wistar rats were infected with 25 Fh metacercariae each, of an isolate resistant to ABZ and susceptible to TCBZ2,4. Twelve weeks later (day 0), the rats were assigned to five treatment groups (n=5 each): ABZ group, (ABZ 20 mg/kg PO by three consecutive days), TCBZ group (TCBZ 20 mg/kg PO by three consecutive days), and CONTROL group, without treatment. Twelve hours after the last dose, rats were bleed to quantify drug/metabolites plasma concentration by HPLC. Rats were slaughtered at day +7, to individually count the adult liver flukes. Fh eggs per gram (EPG) post-treatment was also measured. Both, mean flukes and EPG were compared among groups by Wilcoxon Rank Sum Test. Procedures were previously approved by ethics comitee (CICUAL, FCV UNLP).Results: mean flukes´counts (SD) were 2.8 (1.9), 3.0 (1.4), y 3.2 (2.9), since Fh EPGs (SD), were 109.3 (97.6), 0.6 (0.8), y 102.6 (41.3), for the groups ABZ, TCBZ and CONTROL, respectively. Flukes´counts were not different among groups, however, all the parasites recovered from TCBZ treatments were dead, whereas the flukes recovered from the other groups were alive. The mean (SD) plasma concentrations (µg/mL), were 0.48 (0.30), 1.52 (0.75), 4.51 (1.71) and 1.21 (0.65), for ABZ-sulphoxide (ABZSO), ABZ-sulphone (ABZSO2), TCBZ y TCBZ-sulphone (TCBZSO2), respectively.Discussion and Conclussions: the current evaluation confirm the susceptibility/resistant status of the Fh isolate. It showed that TCBZ suscetibility can be demonstrated by this therapeutic schedule in rats. However, although ABZ´s flukes were alive, plasma concentrations of ABZSO in this assay were, comparatively, a half than those previously found in humans, after an ABZ dose of approximately 6 mg/kg5. The validation of this model will allow not only to reduce costs of resistance assays, but also, as rats are monogastric, would lead to a more reliable comparison to human?s physiology. This would improve the currrent knowledge on prevalence of fasciolicides´ resistance in Fh from highly endemic regions