Positron emission tomography imaging of poststroke angiogenesis

Area of Science:

• Neuroscience
• Medical Imaging
• Molecular Biology

Background:

• Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) are crucial for neurovascular repair following stroke.
• Noninvasive imaging of VEGFR expression can aid in understanding and managing post-stroke recovery.

Purpose of the Study:

• To utilize positron emission tomography (PET) for noninvasive imaging of VEGFR expression in a rat stroke model.
• To analyze the kinetics of VEGFR expression during post-stroke angiogenesis.

Main Methods:

• Female Sprague-Dawley rats underwent middle cerebral artery occlusion surgery.
• Weekly MRI, (18)F-FDG PET, and (64)Cu-DOTA-VEGF(121) PET scans were performed.
• Histological analyses (VEGFR, BrdU, lectin staining) and autoradiography validated in vivo imaging results.

Main Results:

• PET imaging revealed VEGFR expression peaking around 10 days post-stroke, correlating with neovascularization.
• Specificity of (64)Cu-DOTA-VEGF(121) uptake for VEGFR was confirmed through control experiments.
• No significant VEGFR tracer uptake was observed in sham-operated control rats.

Conclusions:

• This study demonstrates the first successful noninvasive evaluation of VEGFR expression kinetics in a rat stroke model.
• In vivo VEGFR imaging holds potential as a clinical tool for planning and monitoring therapies to enhance post-stroke angiogenesis.