ABSTRACT NUMBER: ESOC2026A1814 THE ADMA–NO–NOX2 AXIS AND ITS ASSOCIATION WITH LEPTOMENINGEAL COLLATERAL IMPAIRMENT IN ACUTE ISCHEMIC STROKE

Abstract Background and aims Leptomeningeal collateral (LMC) circulation helps preserve brain tissue during acute ischemic stroke (AIS), with poor collateral status predicting worse outcomes. This study assessed the association between asymmetric dimethylarginine (ADMA), LMCs, infarct volume, and oxidative stress in 101 AIS patients with large vessel occlusion within 6h or wake-up stroke. Methods LMC status was graded using the Menon score (poor, intermediate, or good) on CT angiography, and recanalization was assessed by the modified Thrombolysis in Cerebral Infarction score. Serum ADMA, NADPH oxidase 2 (NOX2), and nitric oxide (NO) levels were measured at admission (<6h, T0), 24h (T1), and 48h (T2). Results Among patients, 43.1% had good, 35.3% intermediate, 21.6% poor LMC status. Higher admission ADMA levels were significantly associated with poor LMC at T0 (p=0.028) and more severe neurological deficits at T1 and T2 (p=0.005, p=0.008). ADMA levels increased over time (p=0.046), and correlated with NOX2 at T1 (p<0.001). Rising NOX2 was associated with increased neutrophils (p=0.013) and decreased lymphocytes (p=0.006). Conclusions ADMA may impair endothelial function by reducing NO availability and enhancing NOX2-driven oxidative stress. These findings support a role for the ADMA-NO-NOX2 axis in limiting collateral circulation. Targeting this axis may represent a therapeutic strategy to improve outcomes in AIS. Conflict of interest Manuela De Michele: nothing to disclose