Abstract WP346: Clot Biology Across Time: Multi-Omic Insights into Stroke Thrombi and Onset-to-Needle Intervals

Background and objectives: Histologic and transcriptomic analyses of stroke thrombi retrieved from mechanical thrombectomy have identified features associated with outcome. Yet, little information is known about how clot biology is related to time since onset in stroke. Studies have shown the predictive capacity of histology or expression features in isolation, but few have investigated how paired omics analyses can improve understanding of clot pathobiology. Our objective was to identify histomics, transcriptomics, and mechanisms associated with onset-to-needle times in stroke. Methods: We performed paired histologic/transcriptomic analyses of 32 stroke clots. The outcome variable was onset-to-needle time. Clots were H&E-stained and imaged at 40X. An established digital pathology pipeline was used to extract 237 histomic features. When dichotomized by either the high or low onset-to-needle time, differentially expressed genes (DEGs) were identified as those with absolute fold-change >1.5 and q < 0.05. DEGs were visualized in a heatmap plotted against normalized door-to-needle times. Correlation analysis between histomics and door-to-needle times was used to identify significantly correlated clot features (Pearson correlation, q-value<0.05). Results: For onset-to-needle times, we identified 90 significant DEGs (q-value<0.05); 35 positive DEGs and 55 negative DEGs. 0.98 ± 0.08) (Figure 1). Positively associated DEGs yielded few-no ontology terms. Conversely, negatively associated DEGs yielded a rich set ontology terms in ClusterProfiler, including interferon signaling pathways, focal adhesion, and intracellular signaling pathways (Figure 2). 4 histomics features were associated with onset-to-needle time (q-value<0.05) and included those related to fibrin-platelet (fp) distribution (fp_75_area, fp_75_major_axis_length, fp_75_perimiter) and the classes of white blood cells present (cfd_class_7) (Figure 3). This suggests that certain white blood cell phenotypes are likely presenting these key molecular pathways associated with time since onset. Conclusion: We identified histologic and transcriptomic features of stroke clots that are significantly associated with onset-to-needle times, revealing distinct biological pathways and clot characteristics tied to treatment timing. These findings underscore the value of integrated histologic and transcriptomic analyses in enhancing our understanding of clot pathobiology and its impact on stroke treatment outcomes.