Suboccipital Cisterna Magna Injection for Vehicle Delivery in Pigs Using Computed Tomography

Gene therapies are being developed for several central nervous system (CNS) disorders. These therapies are primarily administered to the CNS via the cerebrospinal fluid (CSF), as the blood–brain barrier prevents the transport of large molecules to the brain. Currently, intrathecal injection is the most commonly used route of administration over cisterna magna injections in the clinic for gaining access to the CSF. However, studies in nonhuman primates (NHPs) have shown that administering gene therapies via suboccipital cisterna magna injection results in superior distribution and more cells being transduced in the brain compared to lumbar injection. It has also been reported that comparable CNS size is important when translating therapeutic dosages from animal studies to human trials. Therefore, we chose to develop a computed tomography (CT)-guided cisterna magna injection protocol in pigs as they are anatomically closer in size to humans than nonhuman primates and rodents. Pigs are also a readily available and cost-effective large animal model for preclinical studies compared to nonhuman NHPs. In this paper, we describe a method for CT-guided suboccipital cisterna magna injections in pigs. We developed this protocol utilizing CT to confirm needle placement with three-dimensional visualization. A CT-guided injection minimizes procedural risk and can be performed without a contrast agent, which is required in magnetic resonance and fluoroscopy imaging. © 2024 Wiley Periodicals LLC.

Basic Protocol: Computed tomography–guided suboccipital cisterna magna injection in pigs to confirm needle placement prior to the administration of a test article or vehicle