Plasma-derived small extracellular vesicle miR-660-5p as a predictor for carotid plaque vulnerability and postoperative major adverse cardiovascular event risk.

BACKGROUND: Building on our previous isolation of plaque-derived small extracellular vesicles (sEVs) from carotid atherosclerotic stenosis (CAS) patients, this study aimed to identify plasma sEV-encapsulated miRNAs that reflect plaque vulnerability and predict clinical outcomes, based on differentially expressed miRNAs identified in sEVs from stable versus vulnerable plaques. METHODS: CAS patients were retrospectively enrolled into four complementary cohorts: (1) a sequencing cohort (n = 12) for miRNA profiling of plaque-derived sEVs; (2) a discovery cohort (n = 62) to identify candidate plasma-derived sEV miRNAs associated with plaque vulnerability; and (3) validation cohort 1 (n = 180; endarterectomy cases) and (4) validation cohort 2 (n = 326; stenting cases) for validating the diagnostic efficacy of the identified plasma-derived sEV miRNAs. Candidate miRNAs were quantified using a High-throughput nano-bio chip integrated system (HNCIB). Their associations with plaque vulnerability and 3-year post-endarterectomy major adverse cardiovascular events (MACE) were analyzed. RESULTS: MiRNA sequencing revealed significant upregulation of miR-660-5p in vulnerable plaque-derived sEVs. Its expression levels showed a significant positive correlation between matched plaque- and plasma-derived sEVs from the same patient. Moreover, plasma-derived sEV miR-660-5p levels were independently associated with carotid plaque vulnerability in both validation cohorts, defined either by histopathological criteria (endarterectomy cases) or the clinically validated Plaque-Reporting and Data System (RADS) criteria (stenting cases). Additionally, elevated plasma-derived sEV miR-660-5p levels were also associated with a higher risk of 3-year post-endarterectomy MACE. CONCLUSION: Plasma-derived sEV miR-660-5p represents a promising non-invasive biomarker for assessing carotid plaque vulnerability and predicting 3-year MACE risk following carotid endarterectomy, offering potential for improved risk stratification and therapeutic targeting.