Prolonged convection-enhanced delivery into the rat brainstem

Area of Science:

• Neurosurgery
• Biomedical Engineering
• Drug Delivery Systems

Background:

• Convection-enhanced delivery (CED) is a neurosurgical technique for delivering therapeutic agents to the brain.
• Optimizing CED parameters is crucial for maximizing drug distribution and therapeutic efficacy.
• The safety and efficacy of prolonged CED in the brainstem require thorough investigation.

Purpose of the Study:

• To evaluate the safety and determine the achievable distribution volume (V(d)) of prolonged convection-enhanced delivery (CED) in the rat brainstem.
• To assess the histological impact and clinical tolerance of chronic CED infusions in the brainstem.
• To explore the potential of CED for treating brainstem pathologies, such as diffuse pontine gliomas.

Main Methods:

• Stereotactic cannulation of the rat brainstem for infusions.
• Utilized prolonged infusions (24 hours to 7 days) of fluorescein isothiocyanate-dextran to assess V(d).
• Conducted serial neurological examinations and histological analyses to evaluate clinical tolerance and tissue response.

Main Results:

• No observed neurological deficits in animals receiving chronic brainstem infusions.
• Distribution volume (V(d)) increased linearly with infusion volume (V(i)), ranging from 24.8 to 130.6 mm(3).
• Histological analysis revealed minimal necrosis confined to the infusion site and cannula tract.

Conclusions:

• Prolonged CED is a safe method for infusing the rat brainstem, with no identified limitations on V(d).
• Minimal histological alterations suggest a favorable safety profile for chronic brainstem CED.
• The findings support the potential application of CED for therapeutic interventions in diffuse pontine gliomas.