Abstract
Introduction: Stroke is the 2nd leading cause of death globally. Despite the current standard of care for stroke, more than 50% of stroke survivors are chronically disabled, leading to more than $46 billion in annual economic burden in the US alone. It is therefore imperative to develop novel therapies for stroke. Preclinical studies in the past two decades have shown promise in cell therapies for stroke. Intra-arterial (IA) delivery of Mesenchymal Stem Cells (MSCs) is minimally invasive making it attractive for clinical translation. Recent studies from our lab have shown the safety and efficacy of IA-MSC treatment in rodent and canine ischemic stroke models. These studies from our group have established the precise timing and effective dosage of IA-MSC therapy that leads to improved stroke outcomes. It is believed that IA-MSCs exert their protective effects by mediating anti-inflammatory actions. However, this mechanism is not very well studied, specifically in the large animal brain.
Methods: In this study we determined the expression pattern of microglia, astrocytes, the Nod-like receptor 3 (NLRP3) inflammasome pathway markers, inflammatory cytokines and the activity of Nuclear factor kappa B subunit 1 (NF-κB) in the large animal canine brain following IA MSC therapy after ischemic stroke. Immunohistochemistry staining and immunofluorescence imaging of the canine brain cortex and hippocampus were performed.
Results: Numerical quantification showed significant reduction in astrocyte and microglia activation, reduced expression of NLRP3 and Interluekin-1beta at different doses of IA-MSCs (10, 20, and 40 million) at 30 days post-stroke. Results from this study showed a significant dose-dependent reduction in inflammation in the canine hippocampus and the cortex. There was a simultaneous increase in surviving neurons.
Conclusions: These novel findings help us understand inflammation in the canine brain after stroke. Our data further reveal how IA-MSC therapy mediates its action via inflammatory changes. Overall, this approach contributes to developing more robust and engineered IA-MSCs therapies for stroke patients, leading to more effective translation.