Neutrophil-targeted delivery of circSCMH1 unlocks an acute anti-thromboinflammatory function to restore microvascular perfusion in stroke

Objectives: Futile recanalization (FR) after endovascular thrombectomy (EVT) is driven by neutrophil-mediated thromboinflammation, yet conventional neuroprotectants fail to address the spatiotemporal complexity of stroke injury. This study aimed to identify the clinical link between circSCMH1, traditionally viewed as a late-stage repair molecule, and FR, while evaluating its hyperacute anti-inflammatory potential via a neutrophil-targeted delivery system. Methods: We analyzed thrombi and plasma from LVO-AIS patients stratified by functional outcomes. We engineered neutrophil-targeted lipid nanoparticles (circSCMH1@pepLNP) for delivery in a mouse transient middle cerebral artery occlusion model. Therapeutic outcomes were evaluated through infarct volume measurement, histological assessment of NETosis, and intravital two-photon microscopy to monitor real-time neutrophil dynamics and capillary stalling. Results: Clinical analyses showed circSCMH1 was significantly downregulated in FR patients, with its levels negatively correlated with NET burden. Furthermore, circSCMH1-negative neutrophils exhibited a higher propensity for NETosis within the thrombus microenvironment. In mice, circSCMH1@pepLNP achieved specific neutrophil delivery, significantly reduced infarct volume, and suppressed the expression of citrullinated histone H3 and neutrophil elastase. Intravital two-photon and laser speckle imaging further confirmed that this intervention attenuated neutrophil adhesion, increased migratory velocity, and alleviated capillary stalling, thereby restoring cortical microvascular perfusion. Conclusions: Our findings associate neutrophil-specific circSCMH1 downregulation with clinical FR in LVO-AIS. Targeted intracellular delivery reveals an acute anti-thromboinflammatory function that complements established reparative properties, proposing a novel adjunctive approach for EVT to address the spatiotemporal complexity of stroke and improve clinical outcomes.