Plasma proteomics uncovers divergent molecular signatures in ischemic stroke and intracerebral hemorrhage.

backgroundTimely differentiation between ischemic stroke (IS) and intracerebral hemorrhage (ICH) is critical for guiding appropriate acute management strategies. While neuroimaging is the diagnostic gold standard, its accessibility is often limited in urgent clinical settings. Blood biomarkers offer a promising, scalable diagnostic alternative; however, no validated panel is yet available for distinguishing stroke subtypes during the hyperacute phase.

methodsIn a multicenter study, plasma samples were collected within 6 h of symptom onset. A total of 3,072 proteins were measured using Olink® proximity extension assays. We applied differential expression analysis, principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and receiver operating characteristic (ROC) curve evaluation. To interpret the biological relevance of the findings, we conducted functional enrichment and protein-protein interaction (PPI) analyses.

resultsAmong the 388 patients (344 IS, 44 ICH), 2,531 proteins were retained; 878 reached nominal significance (p < 0.05), and 67 remained significant after multiple-testing correction (FDR-adjusted p < 0.05). Of these, 844 were overexpressed in ICH and 34 in IS. GFAP, a glial marker, emerged as the most discriminative biomarker for ICH versus IS (AUC = 0.887; sensitivity: 80%, specificity: 90%), followed by BCAN (AUC = 0.820), SNAP25 (AUC = 0.797), and SPOCK1 (AUC = 0.786). For IS, S100A12 (AUC = 0.677) and MNDA (AUC = 0.657) showed the best performance. Multivariate analyses confirmed the presence of distinct proteomic patterns, with enrichment revealing a significant overrepresentation of neurodevelopmental and synaptic pathways. In PPI networks, GFAP and LYN emerged as central hubs.

conclusionThis study reveals a robust plasma proteomic signature distinguishing IS from ICH within hours of onset. These results lay the groundwork for scalable, blood-based diagnostics to guide early stroke management when imaging is delayed or unavailable.