Microvascular plasticity after experimental stroke: a molecular and MRI study

Area of Science:

• Neuroscience
• Radiology
• Biomedical Engineering

Background:

• Microvasculature is crucial in stroke pathophysiology and repair.
• Angiogenesis presents a promising target for neurorestorative therapies.
• Dynamic microvessel changes post-stroke require further in vivo investigation.

Purpose of the Study:

• To characterize microvascular plasticity up to 25 days post-ischemic stroke.
• To correlate in vivo MRI findings with angiogenic factor expression.
• To explore MRI as a potential biomarker for stroke recovery and therapy.

Main Methods:

• Utilized 7T-MRI to assess vascular permeability, cerebral blood volume (CBV), vessel size index (VSI), and vascular density in a rat stroke model.
• Quantified angiogenic factor expression using RT-qPCR.
• Performed immunohistology for microvessel analysis.

Main Results:

• Identified three stages of microvascular changes: acute (D1-D3), transition (D3-D7), and subacute (D7-D25).
• Observed dynamic changes in angiogenic factors and MRI parameters correlating with these stages.
• Found limited microvessel density at D25, potentially hindering neural repair, despite normal CBV.

Conclusions:

• Multiparametric MRI effectively images functional microvessels and assesses post-stroke angiogenesis.
• MRI can serve as a biomarker for neurorestorative therapy studies.
• Endogenous vessel maturation occurs in the subacute stage, indicating optimal timing for pro-angiogenic treatments.