Ischemic stroke is a leading cause of disability worldwide, marked by profound disruption of the neurovascular unit (NVU), a dynamic grouping of neurons, astrocytes, cerebral endothelial cells (CECs), microglia, pericytes, and oligodendrocytes. While acute stroke interventions such as tissue plasminogen activator and endovascular thrombectomy address reperfusion, they fail to engage the prolonged and cell-specific processes critical for recovery. Extracellular vesicles (EVs), membrane-bound carriers of proteins, lipids, and nucleic acids, have emerged as key modulators of intercellular communication within the NVU. This review synthesizes current evidence on NVU-derived EVs as both regulators and effectors of post-stroke pathology and repair. We highlight the phase-specific roles of EVs in modulating blood-brain barrier (BBB) integrity, thrombosis, angiogenesis, neurogenesis, oligodendrogenesis, synaptic plasticity, and neuroinflammation. This review places special emphasis on how EV cargo reflects the state of their parent cells and how EV-mediated crosstalk orchestrates coordinated neurorestorative responses. We further discuss the dual nature of EVs, their therapeutic potential for stroke, and the methodological challenges impeding clinical translation, including isolation standardization, cell-specific targeting, and regulatory barriers. Thus, adherence to minimal information for studies of extracellular vesicles (MISEV) guidelines is essential to ensure rigor, reproducibility, and transparency. When combined with temporal and cellular specificity, NVU-derived EVs may represent a biomimetic platform for promoting durable recovery in stroke patients.

ObjectivesThrombolytic therapy can eliminate thrombotic masses from the deep veins, but its effectiveness is not always predictable. We hypothesize that blood flow may influence the composition of an acute venous thrombus contributing to unpredictable outcomes. The aim of the study was to take advantage of two available well-established models to compare venous thrombus composition under flow and stasis conditions in vivo.MethodsC57BL/6 mice, 10-12 weeks old, weighing 20-25g, were used in electrolytic (EIM) and ligation (LM) models of VT. Four groups (n = 5) were used to compare the structure of acute (Day (2) and subacute (Day (6) thrombus in the EIM and LM. Venous thrombus was harvested for thrombus weight (TW) measurement and histology. Expression of PAI-1, t-PA, u-PA, and alfa-2-antiplasmin in the vein wall and D-dimer levels in plasma were investigated at Day 2 and 6.ResultsAcute venous thrombus within the EIM was significantly smaller compared to LM (6.2 ± 3.6 vs 26.2 ± 3.6, P < .05). Thrombus formed within the EIM had a significantly higher amount of plasminogen, especially on the surface and in the tail of the thrombus. In addition, a significantly higher concentration of circulating D-Dimer was found within the EIM.ConclusionsRegional venous blood flow pattern may significantly affect the structure and composition of the venous thrombotic masses. Non-occlusive thrombus has a higher potential to be targeted by the fibrinolytic system and fibrinolytic therapy due to a higher plasminogen content and accessibility for plasminogen activators.

Necrotic cell death causes loss of membrane integrity, release of intracellular contents and deposition of necrotic cell debris. Effective clearance of this debris is crucial for resolving inflammation and promoting tissue recovery. While leukocyte phagocytosis plays a major role, soluble factors in the bloodstream also contribute to debris removal. Our study examined whether enzymatic degradation or disassembly of necrotic debris enhances clearance and improves outcomes in a mouse model of drug-induced liver injury. Using intravital microscopy and on-tissue spatially-resolved microproteomics, we demonstrated that necrotic debris is more complex than anticipated, containing DNA, filamentous actin, histones, complement C3, fibrin(ogen) and plasmin(ogen), among many other components. DNase 1 treatment facilitated recovery significantly by enhancing the clearance of DNA from necrotic areas, reducing circulating nucleosomes and actin, and lowering the associated inflammatory response. However, its effect on actin and other damage-associated molecular patterns in necrotic regions was limited. Treatment with short synthetic peptides, specifically 20-amino acid-long positively charged poly L-lysine (PLK) and negatively charged poly L-glutamic acid (PLE), which displace histones from debris in vitro, did not inhibit liver injury or promote recovery. Moreover, activating plasmin to disrupt fibrin encapsulation via tissue plasminogen activator (tPa) led to increased circulating actin levels and worsening of injury parameters. These findings suggest that fibrin encapsulation is important for containing necrotic debris and that enzymatic degradation of necrotic debris is a more effective strategy to enhance tissue recovery than targeting debris disassembly.

Neuroinflammation is widely posited to be a key pathogenic mechanism linking acute organophosphate (OP)-induced status epilepticus (SE) to persistent brain injury and abnormal electrical activity that contribute to epilepsy and cognitive impairment. The plasminogen activation system (PAS) promotes neuroinflammation in diverse neurological diseases but whether it is activated following acute OP intoxication has yet to be evaluated. To address this data gap, we characterized the spatiotemporal expression patterns of multiple components of the PAS in a rat model of acute intoxication with the OP, diisopropylfluorophosphate (DFP). Adult male Sprague Dawley rats administered DFP (4 mg/kg, sc), atropine sulfate (2 mg/kg, im) and 2-pralidoxime (25 mg/kg, im) went into SE that persisted for hours. One day after acute DFP-induced SE, plasmin activity and protein concentrations of plasminogen activator inhibitor-1 (PAI-1) in the plasma were increased, though not significantly. In contrast, acute DFP intoxication significantly increased brain levels of PAI-1, tissue-type plasminogen activator (tPA), urokinase plasminogen activator (uPA), and transcripts of TGF-β in a time- and region-dependent manner. In the cortex and hippocampus, quantification of PAI-1, tPA, and uPA by ELISA indicated significantly increased levels at 1 day post-exposure (DPE). PAI-1 and uPA returned to control values by 7 DPE while tPA protein remained elevated at 28 DPE. Immunohistochemistry detected elevated PAI-1 expression in the DFP brain up to 28 DPE. Co-localization of PAI-1 with biomarkers of neurons, microglia, and astrocytes demonstrated that PAI-1 localized predominantly to a subpopulation of astrocytes. Cytologically, PAI-1 localized to astrocytic end feet, but not adjacent neurovascular endothelium. Electron microscopy revealed neuronal metabolic stress and neurodegeneration with disruption of adjacent neurovascular units in the hippocampus post-DFP exposure. These data indicate that acute DFP intoxication altered PAS expression in the brain, with aberrant PAI-1 expression in a subset of reactive astrocyte populations.

Ventricular arrhythmia is a critical and challenging cardiovascular complication of myocardial infarction (MI). An electrical storm (ES), characterised by three or more episodes of sustained ventricular arrhythmia within 24 hours, poses a significant life-threatening risk. Standard management includes advanced life support (ALS) protocols and specialised pharmacological interventions. We present the case of a 43-year-old female who presented to the emergency department (ED) following an out-of-hospital ventricular fibrillation (OOHVF) arrest, with the return of spontaneous circulation (ROSC) achieved after multiple defibrillation shocks. Electrocardiography (ECG) revealed anterior ST-segment elevation MI (STEMI) involving the left anterior descending (LAD) artery. During her ED stay, she experienced recurrent ventricular fibrillation (VF) arrests requiring repeated defibrillation, adrenaline, amiodarone, and thrombolysis with alteplase. She was subsequently intubated and transferred to a primary percutaneous coronary intervention (PPCI) centre with intensive care support. Angiography confirmed a 100% occlusion of the LAD, which was successfully treated with stenting. The patient was admitted to the intensive care unit (ICU) and later discharged with full neurological recovery, on secondary prevention and heart failure therapy, with follow-up planned. This case underscores the complexity of managing electrical storms in MI, particularly in non-PPCI centres. It emphasises the importance of thrombolysis as an early reperfusion strategy in STEMI, especially when PPCI is not immediately available.

Intravenous thrombolysis using recombinant tissue plasminogen activator (tPA) remains the primary treatment for patients with acute ischemic stroke (AIS). However, the mechanism of tPA-related hemorrhagic transformation (HT) remains poorly understood. Elevation of histidine-rich glycoprotein (HRG) expression was detected by nano-liquid chromatography tandem mass spectrometry at 1 h following tPA infusion as compared to baseline prior to tPA infusion (discovery cohort, n = 10), which was subsequently confirmed in a validation cohort (n = 157) by ELISA. Surprisingly, no elevation of HRG was detected in individuals who subsequently developed HT. During in vitro experiments, HRG reduced neutrophil NETosis, inflammatory cytokine production, and migration across the blood-brain barrier induced by tPA. In a photothrombotic murine AIS model, HRG administration ameliorated HT with delayed thrombolysis, by inhibiting neutrophil immune infiltration and downregulating pro-inflammatory signaling pathways. Neutrophil depletion or NETosis inhibition also alleviated HT, whereas HRG siRNA treatment exacerbated HT. In conclusion, fluctuations in HRG levels may reflect tPA therapy and its associated HT. The inhibitory effect of HRG on neutrophils may counteract tPA-induced immune abnormalities and HT in patients with AIS.