Concurrent profiling of polar metabolites and lipids in human plasma using HILIC-FTMS.

Xiaoming Cai,Ruibin Li

doi:10.1038/srep36490

Abstract

Blood plasma is the most popularly used sample matrix for metabolite profiling studies, which aim to achieve global metabolite profiling and biomarker discovery. However, most of the current studies on plasma metabolite profiling focused on either the polar metabolites or lipids. In this study, a comprehensive analysis approach based on HILIC-FTMS was developed to concurrently examine polar metabolites and lipids. The HILIC-FTMS method was developed using mixed standards of polar metabolites and lipids, the separation efficiency of which is better in HILIC mode than in C5 and C18 reversed phase (RP) chromatography. This method exhibits good reproducibility in retention times (CVs < 3.43%) and high mass accuracy (<3.5 ppm). In addition, we found MeOH/ACN/Acetone (1:1:1, v/v/v) as extraction cocktail could achieve desirable gathering of demanded extracts from plasma samples. We further integrated the MeOH/ACN/Acetone extraction with the HILIC-FTMS method for metabolite profiling and smoking-related biomarker discovery in human plasma samples. Heavy smokers could be successfully distinguished from non smokers by univariate and multivariate statistical analysis of the profiling data, and 62 biomarkers for cigarette smoke were found. These results indicate that our concurrent analysis approach could be potentially used for clinical biomarker discovery, metabolite-based diagnosis, etc.

Highlights

Metabolite profiling is defined as the measurement of low-molecular-weight metabolic analytes and their intermediates that reflect the dynamic response of biological systems to various biological conditions, such as disease and environmental exposure[1,2]
Polar and ionic metabolites, such as organic acids and amino acids, are not suitable to analyze with Reversed phase liquid chromatography (RPLC) because they exhibit low hydrophobicity, which leads to weak interaction with stationary phase, poor retention and separation in RPLC mode[19,37]
We presume that Hydrophilic liquid interaction chromatography (HILIC) can be optimized for concurrent analysis of polar metabolites and lipids in blood plasma samples

Summary

Introduction

Metabolite profiling is defined as the measurement of low-molecular-weight metabolic analytes and their intermediates that reflect the dynamic response of biological systems to various biological conditions, such as disease and environmental exposure[1,2]. It’s necessary to develop a single extraction-single separation approach for concurrent analysis of both polar metabolites and lipids in blood plasma. It is necessary to develop a cocktail of extraction solvents for simultaneous analysis of polar metabolites and lipids in plasma. We presume that HILIC can be optimized for concurrent analysis of polar metabolites and lipids in blood plasma samples. By examining a series of organic extraction solvents, a cocktail of MeOH/ACN/Acetone (1:1:1, v/v/v) was found to be the optimal to pair with HILIC-FTMS for concurrent analysis. This method was further explored for the discovery of smoking-related biomarkers in human blood plasma samples

Objectives

Methods

Results