Introduction

Obesity is a risk-factors associated with metabolic syndrome, causing excess body fat to be accumulated to the extent that it adversely affects health and life expectancy. This work provides  additional characterization of the associated lipids using ion-mobility with collision cross section (CCS) databases.

Methods

Lipid were extracted from a variety of sources including plasma and liver tissue of control, obese and diabetic subjects. Extracts were separated over a 20 min reversed-phase LC gradient and data acquired using a data independent acquisition approach utilizing ion mobility. Data were processed and searched using Progenesis QI and dedicated lipid compound databases, providing normalized label-free quantitation results with additional specificity of CCS measurement.

Preliminary Data

Interrogation of the LC-IM-DIA-MS data revealed over 5000 potential features for further investigation as a result of positive and negative ion acquisitions combined. Data were further interrogated using multivariate statistical analyses, showing clear distinction between control and metabolic syndrome groups. OPLS discriminant analysis revealed 795 potential features that were of significant correlation and covariance. Database searching resulted in 163 candidates. Identifications were scored according to mass accuracy, isotoptic fit, CCS and MS/MS fragmentation. Additional filtering to curate the data was based on mass errors less than 2 ppm, fold change >2, 5% CCS tolerance and ANOVA p-value.