Abstract A054: Targeting Piezo1 Activation Establishes a Reproducible No-Reflow Model

Introduction and Hypothesis: Successful large-vessel recanalization only leads to functional independence in approximately half of patients. Futile recanalization or microcirculatory failure (no-reflow) is considered a key contributor, yet its mechanisms are unclear. Moreover, there is no optimal animal model to mimic its major features currently. Piezo1 is a mechanosensitive ion channel that responds to mechanical forces. Previous studies found that the endothelial Piezo1 channel mediated mechano-feedback control of brain blood flow. We therefore hypothesize that Piezo1 activation might be closely associated with the no-reflow phenomenon. Targeting Piezo1 activation may provide a novel and feasible animal model of no-reflow. Methods: Piezo1 distribution was analyzed using single-cell RNA sequencing datasets, and its expression changes after AIS were examined from the existing database, the endothelial oxygen-glucose deprivation (OGD) model, and the mouse middle cerebral artery occlusion/ reperfusion (MCAO/R) model. Yoda1, a Piezo1-specific agonist, was administrated to the lateral ventricle. Perfusion situation was measured by two-photon microscopy and laser speckle contrast imaging (LSCI). To validate the model across species, arterial spin labeling (ASL) magnetic resonance imaging (MRI), infarct volume measurement and neurological scoring were applied in both rats and mice. Results: Piezo1 was enriched in cerebrovascular endothelial cells and its expression increased within 24 hours after infarction. In normal mice, intracerebroventricular injection of Yoda1 led to capillary occlusion and reduced flow velocity. Furthermore, intracerebroventricular administration of Yoda1 resulted in major pathological features of no-reflow in the mouse MCAO model, including a markedly reduced perfusion after the reperfusion in LSCI, a significantly reduced cerebral blood flow in ASL MRI, a higher infarct size, and a deteriorated neurological function. However, these features were not observed in brain endothelial-specific Piezo1 knock-out mice after stroke onset when Yoda1 was used. In addition, Yoda1 also led to no-reflow features in a rat MCAO model. Conclusion: Piezo1 activation may contribute to no-reflow after AIS recanalization. Intracerebroventricular Yoda1 establishes a reproducible no-reflow model in both mouse and rat. This model may provide a platform for mechanistic studies and therapeutic exploration targeting no-reflow.