Impact on Bile Acid Concentrations by Alveolar Echinococcosis and Treatment with Albendazole in Mice

Alveolar echinococcosis (AE) caused by Echinococcus multilocularis is a chronic, progressive liver disease widely distributed in the Northern Hemisphere. The main treatment options include surgical interventions and chemotherapy with benzimidazole albendazole (ABZ). To improve the current diagnosis and therapy of AE, further investigations into parasite-host interactions are needed. This study used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to assess serum and liver tissue bile acid profiles in the i.p. chronic E. multilocularis-infected mouse model and evaluated the effects of the anthelmintic drug ABZ. Additionally, hepatic mRNA and protein expression of enzymes and transporters regulating bile acid concentrations were analyzed. AE significantly decreased unconjugated bile acids in serum and liver tissue. Taurine-conjugated bile salts were unchanged or increased in the serum and unchanged or decreased in the liver. Ratios of unconjugated to taurine-conjugated metabolites are proposed as useful serum markers of AE. The expression of the bile acid synthesis enzymes cytochrome P450 (CYP) 7A1 and aldo-keto reductase (AKR) 1D1 tended to decrease or were decreased in mice with AE, along with decreased expression of the bile acid transporters Na+/taurocholate cotransporting polypeptide (NTCP) and bile salt efflux pump (BSEP). Importantly, treatment with ABZ partially or completely reversed the effects induced by E. multilocularis infection. ABZ itself had no effect on the bile acid profiles and the expression of relevant enzymes and transporters. Further research is needed to uncover the exact mechanism of the AE-induced changes in bile acid homeostasis and to test whether serum bile acids and ratios thereof can serve as biomarkers of AE and for monitoring therapeutic efficacy.