Mass spectrometry based metabolomics to study the development of Non-alcoholic steatohepatitis

It can be hypothesized that the development of non-alcoholic steatohepatitis (NASH) is accompanied by severe changes at the metabolic level. Studying the metabolome may reveal insights in the underlying mechanisms leading from steatosis to the development of NASH and its progression to cirrhosis. Metabolomics attempts the comprehensive and quantitative analysis of metabolites in a biological system. Two complementary approaches are used for metabolomic investigations: metabolic fingerprinting and metabolic profiling. Metabolic fingerprinting aims to identify patterns or “fingerprints“ of metabolites, which change in response to perturbations. In metabolic profiling, quantitative analytical methods are developed for metabolites in a metabolic pathway.This contribution will present two robust analytical methods for metabolic profiling and metabolic fingerprinting that were used to quantitatively probe changes in the metabolome associated with the development of NASH. Metabolic fingerprinting was performed by gas chromatography coupled to mass spectrometry (GC-MS). Furthermore, an LC–ESI-MS/MS method was developed for the quantitative determination of 14 intermediates of the methionine and polyamine pathways with lower limits of quantification in the range of 5.0–500 nM [1]. Preliminary studies were performed with samples from a long-term feeding study. BALB/c mice were fed a control or a high fat diet. Liver tissue extracts were subjected to metabolic fingerprinting by GC-MS. A clear segregation of the two groups was observed in a principal component analysis. The identification of discriminating metabolites is in progress. Metabolic changes in the methionine and polyamine pathways were analyzed in methanolic liver extracts. The preliminary data from the liver extracts of mice fed the paigen diet show a significant increase for purescine and 5-deoxy-5-(methylthio)adenosine, while S-adenosyl -homocysteine, spermidine, spermine and acetylspermine were down regulated.

Literatur:

1. Stevens AP, Dettmer K, Kirovski G, Samejima K, Hellerbrand C, Bosserhoff AK, Oefner PJ: Quantification of intermediates of the methionine and polyamine metabolism by liquid chromatography-tandem mass spectrometry in cultured tumor cells and liver biopsies. J Chromatogr A 2010, 1217(19):3282-3288.

Metabolomics - NASH