MSACL 2019 EU Abstract

Implementation of Lipidomics in the Clinical Routine: Can Fluoride/Citrate Blood Sampling Tubes Improve Preanalytic Stability?

Lisa Hahnefeld (1), Robert Gurke (1,2), Dominique Thomas (1), Yannick Schreiber (2), Stephan M. G. Schäfer (2), Sandra Trautmann (1), Isabel Faria Snodgrass (1,2), Daniel Kratz (1), Gerd Geisslinger (1,2), Nerea Ferreirós (1)
(1) pharmazentrum frankfurt/ ZAFES, Institute of Clinical Pharmacology, Goethe University, Frankfurt, Germany (2) Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Branch for Translational Medicine and Pharmacology TMP, Frankfurt, Germany

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Lisa Hahnefeld (Presenter) Clinical Pharmacology, Goethe University Frankfurt >> POSTER (PDF)

Presenter Bio: Lisa Hahnefeld studied pharmacy at the Goethe University in Frankfurt from 2010 to 2015. At the end of 2015, she graduated and received her approbation as a pharmacist. Since January 2016, she works as a PhD Student at the Institute of Clinical Pharmacology at the University hospital of the Goethe University in Frankfurt. Her research focuses on the development of untargeted LC-QTOF methods for the quantification of small endogenous molecules, especially lipid mediators, in biological matrices.

Relevant Financial Disclosures (within past 24 months) Grant/Research Support German Research Foundation Conflict mitigation NOT REQUIRED.

INTRODUCTION
Lipid compounds are of great interest as potential biomarkers for several diseases. Discovering biomarkers is very challenging since their suitability must be validated, requiring not only robust analytical procedures but also ensuring the quality of the whole analytical process from sampling to data analysis. In particular, the impact of preanalytical sample handling on analyte stability is a rarely described but very important parameter in analyzing any endogenous compound.

OBJECTIVE
The primary objective of the study was assessing the preanalytical stability of several lipid mediators in human whole blood or plasma samples under different sampling and storage conditions.

METHODS
Whole blood and plasma samples of healthy volunteers where incubated at room temperature as well as in ice water for different periods of time ranging from 20 minutes to 24 hours. The impact of two different anticoagulants, K3EDTA and sodium fluoride/citrate, on lipid stability under these conditions was evaluated. The concentrations of several lipid mediators were determined via targeted LC-MS/MS quantification complemented by a non-targeted lipidomics screening using LC-QTOFMS.

RESULTS
The results show that concentrations for several endogenous lipids vary when whole blood and plasma samples are processed at room temperature, whereas most lipids were stable for 4h in ice water. Surprisingly, the concentrations of the endocannabinoids 2-arachidonoyl glycerol (2-AG) and arachidonoyl ethanolamide (AEA) increased in K3EDTA whole blood after storage in ice water for only 20 min. Concentrations after 20 min were 0.715 ± 0.11 ng/mL for 2-AG (t0 = 0.368 ± 0.117 ng/mL)and 0.255 ± 0.047 ng/mL for AEA (t0 = 0.195 ± 0.058 ng/mL). When using sodium fluoride/citrate blood collection tubes, this concentration increase could be prevented and furthermore, the stability of several other lipids was improved as well.

CONCLUSION
Based on the results presented here it is concluded that for endocannabinoid measurement it is absolutely necessary to keep blood sampling and plasma processing time under one hour to avoid ex-vivo formation of these analytes. It is worth mentioning that the baseline lipid levels differ for K3EDTA and sodium fluoride/citrate blood sampling tubes, which emphasizes the importance of traceability of reported plasma concentrations to the used anticoagulant. All in all, the results make clear that several obstacles have to be considered before the proposal of a lipid (mediator) as a potential biomarker for the clinical practice.