ISBN 978-3-8439-3152-6

978-3-8439-3152-6, Reihe Lebensmittelchemie

Ernst Meiß
Entwicklung von Massenspektrometrie-basierten Non-Targeted- und Targeted-Metabolomics-Methoden zur Identifizierung neuer und quantitativen Bestimmung bekannter potentieller Biomarker zu Diabetes mellitus

225 Seiten, Dissertation Universität Hamburg (2017), Softcover, A5

Zusammenfassung / Abstract

approaches for the identification of unknown potential biomarkers for diabetes mellitus and related diseases as well as quantitative determination of known diabetes-linked key metabolites.

To meet this goal, a novel non-targeted metabolomics platform based on UHPLC-UHR-QTOF-MS(/MS) for the assessment of plasma non-polar metabolites was developed. This method was applied to a longitudinal mouse obesity study comparing mice on control and high fat diet, respectively. Plasma metabolites were determined 2, 4, 8 and 16 weeks after initiation of feeding. Multivariate analysis of the metabolite dataset showed clear differentiation of the feeding groups after 8 weeks when the high-fat-diet-fed mice exhibited clear signs of insulin resistance. The discrimination of the groups was due to changes in various metabolic pathways including, among others, glycerophospholipid, sphingolipid and cholesterol metabolism. From 81 compounds with a p-value lower than 0.05, a total of 19 metabolites could be clearly identified due to their accurate mass, isotopic and fragmentation pattern as well as retention time. Six metabolites have not yet been described in the literature and are therefore novel potential biomarkers for diabetes mellitus.

Biomarker studies for metabolic disorders like diabetes mellitus are an important approach towards a better understanding of the underlying pathophysiological mechanisms of diseases. To accomplish this goal, a method approach for the quantitative determination of 74 potential metabolite biomarkers for diabetes mellitus and diabetic nephropathy in serum were developed and validated. Several studies have shown that the concentrations of many polar metabolites like amino or organic acids are changed in organism suffering from diabetes. Analyzing polar analytes presents a challenge in liquid chromatography coupled with ESI–MS/MS. Considering those reasons the decision was taken to develop a specific ESI–QqQ–MS/MS-method approach for quantitative determination of these polar metabolites. A subsequent method validation was carried out for both HILIC and RP chromatography with respect to the validation guidelines of the Food and Drug Administration. Furthermore, the method presented here was applied to serum samples of GIPRdn transgenic mice, a diabetic strain developing diabetic nephropathy, and non-transgenic littermate controls. Significant, diabetes-associated changes were observed for the concentrations of 21 out of 62 metabolites.