Cross-Platform Comparison of Untargeted and Targeted Lipidomics Approaches on Aging Mouse Plasma

Abstract

Lipidomics – the global assessment of lipids – can be performed using a variety of mass spectrometry (MS)-based approaches. However, choosing the optimal approach in terms of lipid coverage, robustness and throughput can be a challenging task. Here, we compare a novel targeted quantitative lipidomics platform known as the Lipidyzer to a conventional untargeted liquid chromatography (LC)-MS approach. We find that both platforms are efficient in profiling more than 300 lipids across 11 lipid classes in mouse plasma with precision and accuracy below 20% for most lipids. While the untargeted and targeted platforms detect similar numbers of lipids, the former identifies a broader range of lipid classes and can unambiguously identify all three fatty acids in triacylglycerols (TAG). Quantitative measurements from both approaches exhibit a median correlation coefficient (r) of 0.99 using a dilution series of deuterated internal standards and 0.71 using endogenous plasma lipids in the context of aging. Application of both platforms to plasma from aging mouse reveals similar changes in total lipid levels across all major lipid classes and in specific lipid species. Interestingly, TAG is the lipid class that exhibits the most changes with age, suggesting that TAG metabolism is particularly sensitive to the aging process in mice. Collectively, our data show that the Lipidyzer platform provides comprehensive profiling of the most prevalent lipids in plasma in a simple and automated manner.

Molecular Choreography of Acute Exercise

“…Plasma samples were thawed on ice, prepared and analyzed in a randomized order. Plasma lipids were extracted using a biphasic separation protocol with ice-cold methanol, methyl tert-butyl ether (MTBE) and water (Contrepois et al, 2018). Briefly, 300 μl of methanol spiked-in with internal standards (provided with the Lipidyzer platform) was added to 40 μl of plasma and vortexed for 20 s. Lipids were solubilized by adding 1,000 μl of MTBE and incubated under agitation for 30 min at 4°C.…”

Combining mass spectrometric platforms for lipidome investigation - Application to the characterisation of disruptions in the lipid profile of pig serum upon β-agonist treatment

“…In Lipidyzer™, TG results were expressed with the shorthand annotation nomenclature (total number of carbons and unsaturations among the three FA chains and the precision on one of them), such as “TG51:1-FA16:0”. While technically correct, this leads to an overestimation of the TG, as previously highlighted in the literature [18]. Moreover, several Lipidyzer™ candidates ( e.g.…”

“…It is interesting to note that this specific platform allowed obtaining confident results on TG and the position ( sn -1(3) versus sn -2) of their constituting FA chains. Thus, it yielded finer results than the combined use of non targeted and Lipidyzer platforms ‒an approach that was already explored by Contrepois et al [18].…”

“…Globally, across the diverse methods and strategies, it appears that no single workflow is sufficient for a wide and complete lipidome characterisation. In such context, the combination of non-targeted and targeted approaches from various complementary techniques is expected to provide an optimal strategy [18] that would further allow discovering unexpected biomarker signals.…”

“…Since they differ in technology (ion mobility, LC, HRMS, MS/MS) and approach (targeted, non-targeted), this combination is expected to provide both enhanced lipid coverage reliability in the obtained results. In comparison with other multi-platforms approaches published by other groups[18], this original strategy aims to further enhance TG analysis, using a dedicated platform for quantifying their regioisomeric composition. Although the experimental conditions and samples were selected in order to be in a favourable context where lipidic disruptions are expected, this study is an analytical assessment and does not aim to provide comprehensive new knowledge about biological pathways involved or ractopamine biomarkers.…”