A NMR spectroscopic study of hepatic metabolism in Meriones unguiculatus infected with Echinococcus multilocularis

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Schoen, Jodi Maureen
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Hepatic carbohydrate and lipid metabolism were studied in alveolar echinococcosis using the Meriones unguiculatus/Echinococcus multilocularis host/parasite model system. Carbon-13 decoupled $\sp1$H spin echo NMR spectroscopy, with and without population inversion, was used to monitor (2-$\sp{13}$C) acetate metabolism in the liver of jirds infected with Echinococcus multilocularis. Thirty minutes after injection of labeled acetate solution into the portal vein, $\sp{13}$C enrichment was observed in hepatic acetate, $\beta$-hydroxybutyrate, succinate, alanine, lactate and glucose. At 120 min. there was a significant decrease in the amount of label present in all these metabolites. For E. multilocularis cysts, 30 min. post injection of (2-$\sp{13}$C) acetate, $\sp{13}$C enrichment was observed in the same metabolites as in the host livers and, in addition, citrate. More label was present after 120 min. in cyst glycogen, glucose, succinate, alanine and lactate, but less in acetate and $\beta$-hydroxybutyrate, than in the corresponding metabolites in the 30 min. group. The presence of $\sp{13}$C enriched glucose in the cyst and its increase in enrichment with time strongly suggests that the parasite is siphoning off glucose that is newly synthesized by the host. $\sp1$H NMR spectroscopy was used to investigate changes in composition of hepatic lipids. It was found that livers from infected jirds had less total glycerophospholipids (GPL), phosphatidylinositol (PTI), phosphatidylcholine (PTC) and cholesterol (CTL) but more phosphatidylethanolamine (PTE) than those of uninfected controls. (Abstract shortened by UMI.)