BACKGROUND: The dramatic clinical improvement offered by mechanical thrombectomy raised questions about the relevance of prior intravenous thrombolysis in large-vessel occlusion strokes. Hence, studying intravenous thrombolysis susceptibility and its dependence on thrombus composition is crucial. We used an observational proteomic study of whole thrombi retrieved by mechanical thrombectomy to identify factors associated with fibrin content and fibrinolytic activity (FA). METHODS: In 104 stroke patients, the thrombi proteome was established by mass spectrometry coupled to liquid chromatography. FA was estimated in clots both outside (FA _out ) by measuring D-dimer levels at the blood-thrombus interface and inside (FA _in ) by evaluating the ratio of fibrinogen α to its plasmin-cleaved forms using proteomics coupled with protein electrophoresis. The factors associated with fibrin content, FA _in , and FA _out were determined by intravenous thrombolysis-adjusted linear regression. RESULTS: FA _out ( P <0.0001) and FA _in ( P =0.0147) were driven by recombinant tissue-type plasminogen activator (r-tPA) administration (47/104) and thrombus composition. Indeed, FA _out was greater with fibrin-rich than erythrocyte-rich thrombi, presumably because of more (r)tPA substrates. Thus, FA _out was increased with cardioembolic thrombi (72/104), which are rich in fibrin ( P =0.0300). Opposite results were found inside the thrombus, suggesting that (r)tPA penetrability was hampered by the density of the fibrinous cap. Moreover, blood cells had a strong impact on thrombus structure and susceptibility to (r)tPA. Indeed, fibrin content was negatively associated with erythrocyte-specific proteins in the thrombus, admission hematocrit ( P =0.0139), and hemoglobin level ( P =0.0080), which underlines the key role of erythrocytes in thrombus composition. Also, an increased number of neutrophils impaired FA _out ( P =0.0225), which suggests that their aggregation around the thrombus prevented the (r)tPA attack. Only FA _out was significantly associated with reduced thrombus weight ( P =0.0310), increased recanalization rate ( P =0.0150), good clinical outcome ( P =0.0480), and reduced mortality ( P =0.0080). CONCLUSIONS: Proteomics can offer new insights into the close relationship between thrombus composition and susceptibility to fibrinolysis, paving the way for new adjuvant therapies.

Carotid atherosclerotic stenosis (CAS) is a leading cause of ischemic stroke. Current understanding of plaque vulnerability remains largely confined to histopathological characterization. Consequently, identifying molecular determinants of plaque stability represents a major challenge to advance prevention strategies. Untargeted metabolomic analysis was performed using mass spectrometry coupled to liquid chromatography on carotid plaques removed from patients with CAS undergoing endarterectomy. To identify factors influencing plaque stability, we compared 42 asymptomatic with 30 symptomatic CAS patients. Associations between each annotated metabolite in plaques and asymptomatic CAS status were assessed using logistic regression models. Asymptomatic patients exhibited lower plasmatic levels of C-reactive protein (CRP) and higher HDL-cholesterol. Within the plaques, caffeine and its catabolites, paraxanthine and methylxanthine, were associated with plaque stability and were correlated with HDL-cholesterol. Additional plant-based diet biomarkers including N5-acetylornithine, gentisic acid, proline betaine, and homostachydrine were also associated with plaque stability. In contrast, N-methylpyridone carboxamides, reflecting niacin excess, involved in vascular inflammatory processes, were both associated with plaque vulnerability and also correlated with higher CRP. Our findings provide molecular evidence that plant-based diets, including coffee, promote carotid plaque stability, while excessive niacin intake, linked to processed foods, may be detrimental. Metabolomics offers new insights into food exposome-related vascular risk.