oa The MetaQ – a Platform for Targeted Metabolomics Studies in Qatar

Introduction

Metabolomics is a study of small molecule (metabolite) composition in the body fluids, tissue or cell culture samples. Depending on the study objective we can apply non-targeted metabolomics (metabolic profiling), which provides a semi-quantitative, global overview of the organisms metabolic composition, or targeted-metabolomics, which offers quantitative measurements of a given set of metabolites. Until today, valuable samples collected in Qatar were shipped to centers abroad for both targeted and non-targeted metabolomics studies. Using our previous experience from development of a metabolomics platform in Germany, we now introduce a targeted-metabolomics platform in Qatar (MetaQ). By a model cooperation between the interim Translational Research Institute (iTRI) of Hamad Medical Corporation (HMC), which provided hardware components of the platform, and the Virtual Metabolomics Core of Weill Cornell Medicine in Qatar (WCM-Q), providing know-how and data analysis support, MetaQ (based on the AbsoluteIDQ p150 assay Biocrates Life Sciences AG) is offering in-house, quantitative measurements of 163 metabolites including amino acids, carnitines, phosphatidylcholines, and sphingomyelins from different sample types (plasma, dry blood spots, tissue samples and cell culture). To validate the MetaQ platform we used plasma samples which were collected in Qatar in the framework of the QMDiab study. Those samples were previously measured by a well-established metabolomics core at Helmholtz Zetrum Munich in Germany.

Materials and Methods

We used 80 plasma samples from de-identified subjects previously enrolled in the QMDiab study. For targeted metabolomics profiling we used the AbsoluteIDQ p150 assay (Biocrates Life Sciences AG). Samples preparation and metabolite detection was performed at the iTRI, according to the manufacturer instructions (Biocrates Life Sciences AG). Briefly, 10 μL of plasma samples were pipetted onto the kit filter plate and evaporated. Evaporation was performed by using evaporator (Organomotion Microvap 118) under nitrogen atmosphere in the chemical fume hood. Dried plasma samples were derivatized with 5% phenylisothiocyanate for 20 minutes followed by second round of evaporation. In the next step sample metabolites together with internal standards were extracted with methanol and filtrated by centrifugation. The sample extract was transferred into a new deep well plate and diluted with running solvent. Sample injection was performed automatically with the auto sampler (Eksigent EkspertUltraLC100) and the metabolite detection was performed using FIA-MS/MS system on a QTRAP4500 triple quadrupole (ABSciex). Evaluation of the mass spectrometry data was performed using MetIDQ software package (integral part of the Absolute IDQ assay). Statistical data analysis was performed using R-Studio.

Results

The major objective was to introduce and validate a functional, targeted metabolomics platform in Qatar. We used the iTRI in-house workhorse for mass spectrometry, the QTRAP4500 triple quadrupole system equipped with liquid chromatography EkspertUltraLC100. As a method of quality control, after sample measurement, we tested the correlation between samples measured in Qatar and previously in Germany. Correlation between subjects was very high: R² > 0.98. Furthermore, 2/3 of the evaluated metabolites also had a high correlation: R² > 0.5. Among the poorly correlating metabolites, which were mainly below the detection limit, correlation was not expected. In this group several carnitines were found. These results show that the introduced platform is robust, especially given that the measurements were performed 2 years after the initial study in Germany, using different version of the equipment. Moreover, this pilot trial was performed completely manually, which might introduce some variation. Therefore, we are currently procuring a robotic system that will allow high throughput with low variability.

Conclusion

Within the cooperation of an Academic Health System between two leading scientific institutions in Qatar (HMC and Weill Cornell Medical) we established and validated a non-targeted metabolomics platform – MetaQ – which now can serve as a hub for targeted metabolomics studies for researchers of various areas in Qatar. Moreover Biocrates Life Sciences AG also offers assays for bile acids, steroids and biogenic amines that can also be processed on this platform.