Staged anticonvulsant screening for chronic epilepsy

Abstract

ObjectiveCurrent anticonvulsant screening programs are based on seizures evoked in normal animals. One‐third of epileptic patients do not respond to the anticonvulsants discovered with these models. We evaluated a tiered program based on chronic epilepsy and spontaneous seizures, with compounds advancing from high‐throughput in vitro models to low‐throughput in vivo models.MethodsEpileptogenesis in organotypic hippocampal slice cultures was quantified by lactate production and lactate dehydrogenase release into culture media as rapid assays for seizure‐like activity and cell death, respectively. Compounds that reduced these biochemical measures were retested with in vitro electrophysiological confirmation (i.e., second stage). The third stage involved crossover testing in the kainate model of chronic epilepsy, with blinded analysis of spontaneous seizures after continuous electrographic recordings.ResultsWe screened 407 compound‐concentration combinations. The cyclooxygenase inhibitor, celecoxib, had no effect on seizures evoked in normal brain tissue but demonstrated robust antiseizure activity in all tested models of chronic epilepsy.InterpretationThe use of organotypic hippocampal cultures, where epileptogenesis occurs on a compressed time scale, and where seizure‐like activity and seizure‐induced cell death can be easily quantified with biomarker assays, allowed us to circumvent the throughput limitations of in vivo chronic epilepsy models. Ability to rapidly screen compounds in a chronic model of epilepsy allowed us to find an anticonvulsant that would be missed by screening in acute models.

The Dentate Gyrus and Temporal Lobe Epilepsy: An “Exciting” Era

“…Although logical, there was a counterargument that many of the current epilepsy medications were based on drug testing in normal animals. Regardless, there is an increasing need for "high throughput" models such as zebrafish, 32 organotypic hippocampal cultures, 33 patient-derived stem cells, 34 and organoids. 35 Advances in computational models have also led to new ways to study epilepsy.…”

Intrinsic Inflammation Is a Potential Anti-Epileptogenic Target in the Organotypic Hippocampal Slice Model

“…Nevertheless, the OHSC model can still give valuable information on discovering new drug targets and pathways in TBI-induced epilepsy. One good example is the high-throughput in vitro OHSC model recently developed by Staley’s group [ 32 ]. They screened over 400 compounds and found that celecoxib, a selective cyclooxygenase-2 inhibitor, was most effective at inhibiting ictal activity and ictal cell death in OHSCs.…”

How do we use in vitro models to understand epileptiform and ictal activity? A report of the TASK1‐WG4 group of the ILAE/AES Joint Translational Task Force

“…Organotypic hippocampal slice culture has been developed to recapitulate posttraumatic epileptogenesis in vitro. In this model, interictal‐like population spikes develop over a period of roughly 2 weeks in culture and are followed by the generation of spontaneous SLEs . Organotypic cultures must be prepared from very young animals, and the development of epileptiform activity may be sensitive to variations in culture conditions.…”

“…Caveats of using organotypic slice culture include cell death, glial proliferation, and slicing‐ and culture‐induced network reorganization. This approach is especially useful in identifying novel antiepileptogenic compounds, as cultures can be monitored and maintained for prolonged periods …”