Neuropathology of the temporal lobe

Neuropathology of New-Onset Refractory Status Epilepticus (NORSE)

New-Onset Refractory Status Epilepticus (NORSE), including its subtype with a preceding febrile illness known as FIRES (Febrile Infection-Related Epilepsy Syndrome), is one of the most severe forms of status epilepticus. Despite an extensive workup (clinical evaluation, EEG, imaging, biological tests), the majority of NORSE cases remain unexplained (i.e., "cryptogenic NORSE"). Understanding the pathophysiological mechanisms underlying cryptogenic NORSE and the related long-term consequences is crucial to improve patient management and preventing secondary neuronal injury and drug-resistant post-NORSE epilepsy. Previously, neuropathological evaluations conducted on biopsies or autopsies have been found helpful for identifying the etiologies of some cases that were previously of unknown cause. Here, we summarize the findings of studies reporting neuropathology findings in patients with NORSE, including FIRES. We identified 64 cryptogenic cases and 66 neuropathology tissue samples, including 37 biopsies, 18 autopsies, and seven epilepsy surgeries (the type of tissue sample was not detailed for 4 cases). We describe the main neuropathology findings and place a particular emphasis on cases for which neuropathology findings helped establish a diagnosis or elucidate the pathophysiology of cryptogenic NORSE, or on described cases in which neuropathology findings supported the selection of specific treatments for patients with NORSE.

GABAergic Neurotransmission in Human Tissues Is Modulated by Cannabidiol

Recently, the potential use of phytocannabinoids (pCBs) to treat different pathological conditions has attracted great attention in the scientific community. Among the different pCBs, cannabidiol (CBD) has showed interesting biological properties, making it a promising molecule with a high security profile that has been approved for treatment as an add-on therapy in patients afflicted by severe pharmaco-resistant epilepsy, including Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS) and tuberous sclerosis complex (TSC). CBD is pharmacologically considered a "dirty drug", since it has the capacity to bind different targets and to activate several cellular pathways. GABAergic impairment is one of the key processes during the epileptogenesis period able to induce a generalized hyperexcitability of the central nervous system (CNS), leading to epileptic seizures. Here, by using the microtransplantation of human brain membranes approach in Xenopus oocytes and electrophysiological recordings, we confirm the ability of CBD to modulate GABAergic neurotransmission in human cerebral tissues obtained from patients afflicted by different forms of pharmaco-resistant epilepsies, such as DS, TSC, focal cortical dysplasia (FCD) type IIb and temporal lobe epilepsy (TLE). Furthermore, using cDNAs encoding for human GABA_A receptor subunits, we found that α1β2 receptors are still affected by CBD, while classical benzodiazepine lost its efficacy as expected.