Neutrophil-targeted Sivelestat nanoparticles cut cerebral infarct volume and restore neurological function in ischemic stroke.
Background
Ischemic stroke (IS), accounting for 80-90% of all stroke cases, remains a leading cause of disability and mortality with limited effective therapies. A critical driver of IS pathogenesis is the formation of neutrophil extracellular traps (NETs), mediated by neutrophil elastase (NE). Current treatments often fail to address this inflammatory component effectively. Targeting NE to suppress NETosis offers a promising therapeutic avenue to mitigate ischemia-reperfusion injury and improve neurological outcomes.
Study Design
Researchers engineered T-SIV nanoparticles designed for neutrophil targeting and site-specific drug release. These nanoparticles incorporated a formyl peptide receptor (FPR)-specific ligand for neutrophil targeting and reactive oxygen species (ROS)-responsive thioketal linkages for controlled release of the NE inhibitor Sivelestat. The efficacy of T-SIV was evaluated in an in vivo MCAO mouse model of cerebral ischemia-reperfusion injury and in vitro using OGD/R-injured PC12 cells. Primary endpoints included cerebral infarct volume, edema, neurological function, NETosis markers, and microglial polarization.
Results
T-SIV nanoparticles demonstrated multimodal neuroprotection in the MCAO mouse model. They significantly reduced cerebral infarct volume, alleviated brain edema, and restored neurological function. The therapeutic mechanism involved a clear suppression of NE-dependent NETosis. > This suppression of NETosis was coupled with a beneficial shift in microglial polarization towards the anti-inflammatory M2 phenotype, indicating a dual modulation of neuroinflammation. These effects were confirmed in vitro, where T-SIV protected OGD/R-injured PC12 cells. The targeted delivery and ROS-responsive release mechanism ensured effective localized action of Sivelestat.
Why It Matters
This study introduces a novel, targeted approach for ischemic stroke treatment by specifically disrupting the NE-NETs axis and reprogramming the inflammatory microenvironment. For clinicians, this could lead to therapies that more effectively mitigate secondary injury post-stroke, potentially improving patient recovery and reducing long-term disability beyond current thrombolytic or thrombectomy options. The neutrophil-hitchhiking nanoplatform represents a significant step towards precision medicine in neuroinflammation, offering a strategy to deliver therapeutic agents directly to the site of inflammation while minimizing systemic side effects. This approach could be translated into a usable protocol for acute stroke management, pending further preclinical optimization and human trials.