Metabolic changes reveal the development of schistosomiasis in mice

A metabonomic analysis of organ specific response to USPIO administration

As ultrasmall superparamagnetic particles of iron oxides (USPIO) have been widely used in clinical medicine as MRI contrast agents, hence their potential toxicity and adverse effects following administration have attracted particular attention. In the present study, high resolution magic-angle-spinning (1)H NMR spectroscopy coupled with multivariate statistical analysis was used to directly determine the metabolic consequences of specific-tissues, including kidney, liver and spleen following the intravenous administration of USPIO. Alterations of renal, hepatic and splenic function were reflected by changes in a number of metabolic pathways including small molecules involved in energy, lipid, glucose, and amino acids metabolism. The toxicological potential and metabolic fate of USPIO seems to be linked to their surface chemistry and particle size. Hierarchical principal component analysis was used to explore the multidimensional metabolic relationships between various biological matrices such as kidney, liver, spleen, plasma and urine. Information on the involvement of USPIO in transportation, absorption, biotransformation, biodistribution and secretion was derived from metabolic correlation analysis between different organs and biofluids. Such a metabonomic strategy provides methodology for investigating the potential adverse biological effects of similar nanoparticles on the environmental and human health and assessing the drug interventions on the targeted organ.

Chemometric analysis of biofluids from mice experimentally infected with Schistosoma mansoni

Background

The urinary metabolic fingerprint of a patent Schistosoma mansoni infection in the mouse has been characterized using spectroscopic methods. However, the temporal dynamics of metabolic alterations have not been studied at the systems level. Here, we investigated the systems metabolic changes in the mouse upon S. mansoni infection by modeling the sequence of metabolic events in urine, plasma and faecal water.

Methods

Ten female NMRI mice, aged 5 weeks, were infected with 80 S. mansoni cercariae each. Ten age- and sex-matched mice remained uninfected and served as a control group. Urine, plasma and faecal samples were collected 1 day before, and on eight time points until day 73 post-infection. Biofluid samples were subjected to ¹H nuclear magnetic resonance (NMR) spectroscopy and multivariate statistical analyses.

Results

Differences between S. mansoni-infected and uninfected control mice were found from day 41 onwards. One of the key metabolic signatures in urine and faecal extracts was an alteration in several gut bacteria-related metabolites, whereas the plasma reflected S. mansoni infection by changes in metabolites related to energy homeostasis, such as relatively higher levels of lipids and decreased levels of glucose. We identified 12 urinary biomarkers of S. mansoni infection, among which hippurate, phenylacetylglycine (PAG) and 2-oxoadipate were particularly robust with regard to disease progression. Thirteen plasma metabolites were found to differentiate infected from control mice, with the lipid components, D-3-hydroxybutyrate and glycerophosphorylcholine showing greatest consistency. Faecal extracts were highly variable in chemical composition and therefore only five metabolites were found discriminatory of infected mice, of which 5-aminovalerate was the most stable and showed a positive correlation with urinary PAG.

Conclusions

The composite metabolic signature of S. mansoni in the mouse derived from perturbations in urinary, faecal and plasma composition showed a coherent response in altered energy metabolism and in gut microbial activity. Our findings provide new mechanistic insight into host-parasite interactions across different compartments and identified a set of temporally robust biomarkers of S. mansoni infection, which might assist in derivation of diagnostic assays or metrics for monitoring therapeutic response.