Targeting Neutrophil Extracellular Traps for Stroke Prognosis: A Promising Path

Elastase-targeting biomimic nanoplatform for neurovascular remodeling by inhibiting NETosis mediated AlM2 inflammasome activation in ischemic stroke

Neutrophil elastase (NE) is a protease released by activated neutrophils in the brain parenchyma after cerebral ischemia, which plays a pivotal role in the regulation of neutrophil extracellular traps (NETs) formation. The excess NETs could lead to blood-brain barrier (BBB) breakdown, overwhelming neuroinflammation, and neuronal injury. While the potential of targeting neutrophils and inhibiting NE activity to mitigate ischemic stroke (IS) pathology has been recognized, effective strategies that inhibit NETs formation remain under-explored. Herein, a biomimic multifunctional nanoplatform (HM@ST/TeTeLipos) was developed for active NE targeting and IS treatment. The core of the HM@ST/TeTeLipos consisted of sivelestat-loaded ditelluride-containing liposomes with ROS-responsive and NE-inhibiting properties. The outer shell was composed of platelet-neutrophil hybrid membrane vesicles (HMVs), which acted to hijack neutrophils and neutralize proinflammatory cytokines. Our studies revealed that HM@ST/TeTeLipos could effectively inhibit NE activity, thereby suppressing the release of NETs, impeding the activation of the AIM2 inflammasome, and consequently redirecting the immune response away from a pro-inflammatory M1 microglia phenotype. This resulted in enhanced neurovascular remodeling, reduced BBB disruption, and diminished neuroinflammation, ultimately promoting neuron survival. We believe that this innovative approach holds significant potential for improving the treatment of IS and various NE-mediated inflammatory diseases.

The Role of Neutrophils in Multiple Sclerosis and Ischemic Stroke

Inflammation plays an important role in numerous central nervous system (CNS) disorders. Its role is ambiguous-it can induce detrimental effects, as well as repair and recovery. In response to injury or infection, resident CNS cells secrete numerous factors that alter blood-brain barrier (BBB) function and recruit immune cells into the brain, like neutrophils. Their role in the pathophysiology of CNS diseases, like multiple sclerosis (MS) and stroke, is highly recognized. Neutrophils alter BBB permeability and attract other immune cells into the CNS. Previously, neutrophils were considered a homogenous population. Nowadays, it is known that various subtypes of these cells exist, which reveal proinflammatory or immunosuppressive functions. The primary goal of this review was to discuss the current knowledge regarding the important role of neutrophils in MS and stroke development and progression. As the pathogenesis of these two disorders is completely different, it gives the opportunity to get insight into diverse mechanisms of neutrophil involvement in brain pathology. Our understanding of the role of neutrophils in CNS diseases is still evolving as new aspects of their activity are being unraveled. Neutrophil plasticity adds another level to their functional complexity and their importance for CNS pathophysiology.

A promising frontier: targeting NETs for stroke treatment breakthroughs

Stroke is a prevalent global acute cerebrovascular condition, with ischaemic stroke being the most frequently occurring type. After a stroke, neutrophils accumulate in the brain and subsequently generate and release neutrophil extracellular traps (NETs). The accumulation of NETs exacerbates the impairment of the blood‒brain barrier (BBB), hampers neovascularization, induces notable neurological deficits, worsens the prognosis of stroke patients, and can facilitate the occurrence of t-PA-induced cerebral haemorrhage subsequent to ischaemic stroke. Alternative approaches to pharmacological thrombolysis or endovascular thrombectomy are being explored, and targeting NETs is a promising treatment that warrants further investigation.

A Comprehensive Review on the Role of Resting-State Functional Magnetic Resonance Imaging in Predicting Post-Stroke Motor and Sensory Outcomes

Stroke is a major leading cause of chronic disability, often affecting patients' motor and sensory functions. Functional magnetic resonance imaging (fMRI) is the most commonly used method of functional neuroimaging, and it allows for the non-invasive study of brain activity. The time-dependent coactivation of different brain regions at rest is described as resting-state activation. As a non-invasive task-independent functional neuroimaging approach, resting-state fMRI (rs-fMRI) may provide therapeutically useful information on both the focal vascular lesion and the connectivity-based reorganization and subsequent functional recovery in stroke patients. Considering the role of a prompt and accurate prognosis in stroke survivors along with the potential of rs-fMRI in identifying patterns of neuroplasticity in different post-stroke phases, this review provides a comprehensive overview of the latest literature regarding the role of rs-fMRI in stroke prognosis in terms of motor and sensory outcomes. Our comprehensive review suggests that with the advancement of MRI acquisition and data analysis methods, rs-fMRI emerges as a promising tool to study the motor and sensory outcomes in stroke patients and evaluate the effects of different interventions.