Matouk, C. C. | bioRxiv Science

bioRxiv2026

Proteomic and Transcriptomic Differences in Ischemic Stroke Patients with Atrial Fibrillation Versus Carotid Atherosclerosis

BackgroundIschemic stroke occurring in the setting of atrial fibrillation (AF) or carotid atherosclerosis (CA) may reflect distinct underlying biological processes. We integrated proteomic, transcriptomic, and genetic data from different sources to identify circulating proteins and molecular pathways associated with ischemic stroke in patients with AF versus CA. MethodsWe conducted a nested proteomic study within the UK Biobank comparing plasma protein levels among ischemic stroke patients with AF (n=539) and CA (n=127). Linear regression models were used to evaluate 2,923 proteins measured using the Olink Explore platform (false discovery rate [FDR] <0.05). In a separate Yale cohort, we evaluated expression of genes encoding identified proteins in thrombectomy clot single-cell RNA sequencing data from ischemic stroke patients with AF (n=7) or CA (n=7), including cell type-specific expression patterns. We then used summary statistics to perform 2-sample Mendelian randomization analyses using cis-protein quantitative trait loci to evaluate associations between genetically predicted levels of proteins identified in prior analyses and ischemic stroke subtypes. Exploratory pathway enrichment analyses were also performed. ResultsTwelve circulating proteins differed significantly between ischemic stroke patients with AF versus CA. AF was associated with higher levels of NTproBNP, NPPB, and ACP5, and lower levels of APCS, ANGPT2, PAMR1, PRCP, PROS1, LARP1, F7, F10, and LEO1 (all FDR<0.05). Clot transcriptomic analyses showed corresponding differential expression of ACP5, PRCP, LARP1, ANGPT2, and LEO1 across AF versus CA patients. Pathway analyses suggested enrichment of coagulation-related pathways among proteins associated with CA and natriuretic peptide signaling pathways among proteins associated with AF. Mendelian randomization analyses demonstrated associations between genetically predicted protein levels and ischemic stroke subtypes (AF or CA), including cardioembolic stroke for NTproBNPand ischemic stroke for ANGPT2, ACP5, APCS, and PAMR1. ConclusionComplementary proteomic, transcriptomic, and genetic analyses identified differing molecular profiles among ischemic stroke patients with AF versus CA. These findings support established biomarkers, including NTproBNP and coagulation-related proteins, while identifying additional candidate pathways that may contribute to biological differences between these stroke-associated conditions. Further validation in clinically adjudicated and longitudinal cohorts is needed.

neuroscience↗

bioRxiv2020

Leukocyte dynamics after intracerebral hemorrhage in a living patient reveal rapid adaptations to tissue milieu

Intracerebral hemorrhage (ICH) is a devastating form of stroke with a high mortality rate and few treatment options. Discovery of therapeutic interventions has been slow given the challenges associated with studying acute injury, particularly over time, in the human brain. Inflammation induced by exposure of brain tissue to blood appears to be a major part of brain tissue injury. Here we longitudinally profiled blood and cerebral hematoma effluent from a patient enrolled in the Minimally Invasive Surgery with Thrombolysis in Intracerebral Haemorrhage Evacuation (MISTIEIII) trial, offering a rare window into the local and systemic immune responses to acute brain injury. Using single-cell RNA-sequencing, we characterized the local cellular response during ICH in the brain of a living patient at single-cell resolution for the first time. Our analysis revealed rapid shifts in the activation states of myeloid and T cells in the brain over time, suggesting that leukocyte responses are dynamically reshaped by the hematoma microenvironment. Interestingly, the patient had an asymptomatic re-bleed (second local exposure to blood) that our transcriptional data indicated occurred more than 30 hours prior to detection by CT scan. This case highlights the rapid immune dynamics in the brain after ICH and suggests that sensitive methods like scRNA-seq can inform our understanding of complex intracerebral events.

immunology↗