Tamoxifen Treatment in Hamsters Induces Protection during Taeniosis byTaenia solium

Abstract

Human neurocysticercosis by Taenia solium is considered an emergent severe brain disorder in developing and developed countries. Discovery of new antiparasitic drugs has been recently aimed to restrain differentiation and establishment of the T. solium adult tapeworm, for being considered a central node in the disease propagation to both pigs and humans. Tamoxifen is an antiestrogenic drug with cysticidal action on Taenia crassiceps, a close relative of T. solium. Thus, we evaluated the effect of tamoxifen on the in vitro evagination and the in vivo establishment of T. solium. In vitro, tamoxifen inhibited evagination of T. solium cysticerci in a dose-time dependent manner. In vivo, administration of tamoxifen to hamsters decreased the intestinal establishment of the parasite by 70%, while recovered tapeworms showed an 80% reduction in length, appearing as scolices without strobilar development. Since tamoxifen did not show any significant effect on the proliferation of antigen-specific immune cells, intestinal inflammation, and expression of Th1/Th2 cytokines in spleen and duodenum, this drug could exert its antiparasite actions by having direct detrimental effects upon the adult tapeworm. These results demonstrate that tamoxifen exhibits a strong cysticidal and antitaeniasic effect on T. solium that should be further explored in humans and livestock.

In Vitro and In Vivo Effects of Tamoxifen against Larval Stage Echinococcus granulosus

“…As was mentioned previously, TAM induces protection against the in vivo establishment of T. solium and T. crassiceps (12,13). Although the conditions used in our experiments are different, since E. granulosus is a tissue parasite, our results coincide.…”

“…Recent evidence revealed that estrogens can affect Taenia physiology (13,36). Within this line of evidence, the efficiency of chemoprotective TAM treatment suggests a possible role for the estrogens in Echinococcus development.…”

“…Interestingly, this antiestrogenic drug has also proved to be effective against several protozoan parasites, including Leishmania major, Leishmania braziliensis, Leishmania chagasi, Leishmania amazonensis, and Trypanosoma cruzi (9)(10)(11). Furthermore, the effect of TAM on cestode parasites has been studied in Taenia crassiceps and Taenia solium (12,13). In fact, TAM inhibits T. crassiceps and T. solium proliferation and in vitro viability, whereas it induces protection against the infection in murine and hamster models, respectively (12,13).…”

“…Furthermore, the effect of TAM on cestode parasites has been studied in Taenia crassiceps and Taenia solium (12,13). In fact, TAM inhibits T. crassiceps and T. solium proliferation and in vitro viability, whereas it induces protection against the infection in murine and hamster models, respectively (12,13). Antiestrogenic drugs have never been studied in E. granulosus.…”

Repurposing drugs for the treatment and control of helminth infections

“…A follow-up study showed that tamoxifen decreased the intestinal establishment of T. solium in hamsters by approximately 70%. Moreover, tamoxifen induced morphological changes: the recovered tapeworms appeared like scolices without strobilar development and consequently showed an 80% reduction in length ( Escobedo et al, 2013 ). Yet the taenicidal and cysticidal potential of tamoxifen has not been evaluated in humans and livestock.…”