Application of Lipid Class Ratios for Sample Stability Monitoring-Evaluation of Murine Tissue Homogenates and SDS as a Stabilizer

Lipids are a ubiquitous class of structurally complex molecules involved in various biological processes. In the fast-growing field of lipidomics, preanalytical issues are frequently neglected. Here, we investigated the stability of lipid profiles of murine liver, brain, lung, heart, and spleen homogenates by quantitative flow injection analysis using tandem mass spectrometry and high-resolution mass spectrometry. Storage of tissue homogenates at room temperature showed substantial alterations of the lipid profiles reflecting lipolytic action. Therefore, ratios of ceramide to sphingomyelin, lysophosphatidylethanolamine to phosphatidylethanolamine, lysophosphatidylcholine to phosphatidylcholine, and diglyceride to triglyceride were applied to monitor sample stability and the effect of sodium dodecyl sulfate (SDS) as a potential stabilizing agent. The addition of SDS led to a concentration-dependent stabilization of lipid profiles in liver, brain, and heart homogenates, while in lung and spleen homogenates, in particular, the lysophosphatidylethanolamine to phosphatidylethanolamine ratio increased upon addition of SDS. In conclusion, we demonstrated that lipid class ratios reflecting lipolytic activity could be applied to evaluate both the stability of samples and the influence of stabilizers.

Automated summary

In this study, the stability of lipid profiles in tissue homogenates was investigated, with ratios of lipid classes used to evaluate sample stability and the impact of stabilizers. The addition of SDS showed concentration-dependent stabilization of lipid profiles in some tissues, while causing an increase in a specific lipid ratio in others. These findings demonstrate the potential of lipid class ratios to assess sample stability and the effects of stabilizing agents.