Investigation of heart lipid changes in acute β-AR activation-induced sudden cardiac death by time-of-flight secondary ion mass spectrometry

Abstract

Sudden cardiac death (SCD), one of the most common causes of human death, has become a major health and social problem. The postmortem diagnosis and prevention of SCD remain primary challenges in the medical community due to the lack of reliable diagnostic biomarkers. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a sensitive surface analysis technique for analyzing tissue slices with high spatial resolution. Here, ToF-SIMS followed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were employed to study the SCD mouse myocardium samples and obtain high-resolution chemical mappings and mass spectra. Distinction between normal control (NC) and acute β-adrenergic receptor (β-AR) activation-induced SCD groups was primarily due to the changes of diacylglycerols (DAG), phosphatidylcholine (PC), lysophosphatidylcholine (LysoPC) and sphingomyelin (SM) in positive mode. Meanwhile, chemical mapping of the myocardium showed different lipid distributions in the SCD mouse myocardium. The metabolite alterations in mouse models were further verified by analyzing the heart tissue sections of a 28-year-old woman that died from isoprenaline injection. This pilot study demonstrated the significance of ToF-SIMS in characterizing the lipid variations in SCD heart tissues and might contribute to the postmortem diagnosis of SCD, the discovery of molecule candidates to discriminate the progression of SCD and the understanding of the potential postmortem diagnostic significance of SCD.