Large Animal Epilepsy Model Platform: Kainic Acid Porcine Model of Mesial Temporal Lobe Epilepsy

Translational animal models are essential for advancing neuromodulation therapies for drug-resistant epilepsy. Large animal epilepsy models capable to accommodate implantable neuromodulation devices designed for humans are needed to advance novel neuromodulation therapies. This study aimed to establish and characterize a kainic acid (KA) porcine model of mesial temporal lobe epilepsy (mTLE) as a platform for pre-clinical stimulation therapy development and testing. We developed a novel platform integrating MRI-guided stereotactic techniques for electrode implantation into bilateral hippocampal (HPC) and anterior nucleus of thalamus (ANT) and intra-hippocampal KA infusion in six domestic pigs. The platform enabled acute intraoperative local field potential (LFP) monitoring in freely behaving animals using a 16-channel fully implantable neural stimulating and recording device designed for human use. Neuropathology was assessed using Cresyl violet staining. Intra-hippocampal KA infusion successfully induced spontaneous electrophysiological features of mTLE, including interictal epileptiform discharges (IEDs), acute status epilepticus (SE), and seizures. Acute SE occurred in all pigs; four survived chronically. Surviving animals exhibited spontaneous IEDs (4/4) and seizures (3/4), ranging from subclinical events to focal and generalized tonic-clonic seizures. Single pulse evoked potentials confirmed functional ANT-HPC connectivity. Histology showed neuronal loss and disorganization consistent with human mTLE. The KA-induced porcine mTLE model provides a crucial translational platform uniquely accommodating human-sized neuromodulation devices for testing and validation in freely behaving animals. It enables the development of advanced strategies like automated seizure diaries and closed-loop therapies targeting Papez circuit nodes, directly addressing unmet needs in developing neuromodulation therapies for drug-resistant epilepsy.

We developed a robust large animal model of mTLE using focal hippocampal KA chemotoxin.This model provides a pre-clinical platform for both intraoperative and long-term electrophysiological studies in behaving animals using MRI-guided stereotactic techniques and implantable devices designed for humans.The porcine KA model replicates hallmarks of human mTLE observed in behaving animals, underscoring its translational potential for evaluating neuromodulation devices and development of novel neuromodulation therapies.