MAPPING LIPIDOMIC CHANGES AS SURROGATE BIOMARKERS OF STROKE PROGRESSION

Stroke triggers dynamic, time-dependent changes in brain lipid composition, which are critical for neuronal survival and inflammatory responses. Characterizing these dynamics is challenging due to spatial and temporal heterogeneity. Here, we combine ultra-high-performance liquid chromatography (UHPLC) and matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) to achieve high-resolution, region-specific analysis of post-stroke lipid alterations.
Adult male Sprague-Dawley rats were subjected to transient middle cerebral artery occlusion (tMCAO, 75 min). Brains were collected at 1, 3, 7, 14, 21 and 28 days post-stroke, then either cryosectioned for MALDI-IMS or processed for lipid extraction and UHPLC analysis. MALDI-IMS mapped lipid spatial distribution at 100 μm/pixel, while UHPLC provided quantitative lipid identification. Adjacent sections underwent immunohistochemistry with anti-CD11b and anti-NeuN to assess neuroinflammation and neuronal loss.
Following stroke, lipid profiles exhibited dynamic, time-dependent changes. Principal component analyses (PCA) scatter plots revealed clustering by post-stroke timepoints. During the acute phase (day 1), structural phospholipids, including phosphatidylethanolamine (PE) and phosphatidylinositol (PI), were reduced, reflecting acute neuronal injury and initiation of cell death. The subacute phase (days 3-7) was marked by accumulation of ceramides, cholesterol, and di- and tri-acylglycerols (DG and TG), consistent with peak inflammation and microglial activation. In the chronic phase (from day 14 onward), lipid profiles progressively stabilized, suggesting attenuation of inflammation and ongoing tissue remodelling.
This integrated MALDI-IMS and UHPLC approach provides high-resolution spatiotemporal maps of lipid alterations after stroke, revealing temporal lipid signatures that track neuronal injury, inflammation, and tissue repair, and highlighting potential biomarkers and therapeutic targets for stroke recovery.