ABSTRACT NUMBER: ESOC2026A1409 PLASMA AND EXOSOMAL BIOMARKERS IN SUBACUTE STROKE: AN OLINK-BASED ANALYSIS OF BAPTISE

Abstract Background and aims Proteomic profiling may improve risk stratification after stroke; however, protein expression signatures related to exercise-based interventions remain insufficiently characterized. Exosomes may provide complementary biomarker information beyond plasma. This study aimed to characterize protein expression in plasma and plasma-derived exosomes in subacute ischemic stroke patients and to explore longitudinal changes associated with aerobic exercise. Methods This exploratory analysis used data from the prospective BAPTISe study accompanying the randomized controlled PHYS-STROKE trial. Plasma and isolated exosome samples from patients were analyzed using the Olink® Cardiovascular II panel at baseline and after a four-week intervention (aerobic training vs. relaxation). Longitudinal and between-group analyses were performed to identify intervention-related changes in protein expression. Multivariable regression analyses were performed, adjusting for age, sex, baseline NIHSS, and time since stroke. Results At baseline, 89 plasma samples (50 training, 39 relaxation) were available for analysis. Eighty-eight proteins were detected in plasma and 70 in exosomes, with 64 overlapping proteins. Over time, plasma analyses showed 30 proteins with increased expression and 14 proteins decreased; in exosomes, 29 increased and 7 decreased. Five proteins (GT, DCN, SCF, THPO in plasma; IL1-RA in exosomes) demonstrated nominal group-by-time differences, which did not remain statistically significant after covariate adjustment. Subgroup analyses and correlations with clinical outcomes will be presented at ESOC. Conclusions Aerobic fitness training was not associated with consistent intervention-related changes in cardiovascular protein expression in plasma or exosomes. Findings highlight the complexity of post-stroke proteomic responses and warrants further investigation to clarify the role of plasma-derived exosomal biomarkers in stroke recovery. Conflict of interest Lavanya Sambaraju: nothing to disclose