In vitro efficacy of albendazole-loaded β-cyclodextrin against protoscoleces of Echinococcus granulosus sensu stricto

Abstract

Background: Cystic echinococcosis (CE), a widespread helminthic disease caused by the larval stage of the dog tapeworm Echinococcus granulosus is represented as a public health concern in humans. The therapeutic failure of albendazole (ABZ) against CE depends on its low aqueous solubility and consequently its erratic bioavailability in plasma. Serious adverse effects have been also observed following the long-term use of ABZ in vivo. Methods: We evaluated the apoptotic effects of ABZ-loaded β-cyclodextrin (ABZ-β-CD) against protoscoleces (PSCs) versus ABZ alone. After 15 h of exposure time, Caspase-3 enzymatic activity was determined by fluorometric assay in PSCs treated with ABZ and ABZ-β-CD. To assess the treatment efficacy of ABZ-β-CD against PSCs, mRNA expression of Arginase (EgArg) and Thioredoxin peroxidase (EgTPx) were quantified by Real-time PCR. Results: A significant scolicidal activity of ABZ was observed only at a concentration of 800 μg/mL (100% PSCs mortality rate after 4 days of exposure), while the 200 and 400 μg/mL ABZ reached 100% PSCs mortality rate after 9 sequential days. The 400 μg/mL ABZ-β-CD had 100% scolicidal rate after 5 days of exposure. Morphological alterations using scanning electron microscopy in treated PSCs revealed that ABZ and ABZ-β-CD induced higher Caspase-3 activity than their controls, indicating a more potent apoptotic outcome on the PSCs. Also, we showed that the ABZ-β-CD can down-regulate the mRNA expression of EgArg and EgTPx, indicating more potent interference against growth and antioxidant properties of PSCs. Conclusions: These data provide new insights into the nanostructured β-CD carriers of ABZ appear as a promising candidate to improve the treatment of CE in vivo models.