GNPS - Sequential Target and Non-target for Global (STANG) metabolomics in a Single Injection to Discover Prognostic Biomarkers of Acute Ischemic Stroke

Non-targeted metabolomics by an LC-MS system offers the advantage of wide signal coverage, enabling the discovery of novel biomarkers. However, it suffers from a low identification rate and limitations due to incomplete databases and reliable bioinformatics software to handle large data sets. On the other hand, targeted metabolomics focuses on specific biomarkers, allowing for a more directed search but potentially limiting the exploration of other potential biomarkers. To address these challenges, we developed a novel method called Sequential Target And Non-target for Global metabolomics (STANG metabolomics) using the functionality of the triple quadrupole-linear ion trap mass spectrometer (Q-Trap MS). This method combines the capabilities of a triple quadrupole for a wide linear range of MRM scans and an ion trap for fast full-scan acquisition. Our approach enables the direct analysis of known metabolites while simultaneously recording mass spectrometry signals of non-targeted substances in the full-scan spectra, facilitating comprehensive biomarker identification. Currently, 448 metabolite targets have been built, and the STANG metabolomics approach was applied to discover prognostic biomarkers of acute ischemic stroke. We identified 32 biomarkers through targeted metabolomics and 83 candidates through non-targeted metabolomics. The top four markers with the highest AUC values are lithocholic acid (AUC=0.999), ursodeoxycholic acid (AUC=0.985), 3,4-Dihydroxyphenylglycol (AUC=0.836), and 4-Hydroxybenzaldehyde (AUC=0.807). This approach shortens sample analysis time, reduces data conversion, increases metabolite coverage, and improves analytical sensitivity and accuracy. The potential of the STANG metabolomics approach was evaluated in discovering prognostic biomarkers of stroke, demonstrating its value as a comprehensive tool for biomarker discovery and disease mechanism elucidation.