Focused review: Clinico-neuropathological aspects of late onset epilepsies: Pathogenesis.

The aim of the present study was to review the current knowledge on the neuropathological spectrum of late onset epilepsies. Several terms including 'neuropathology*' AND 'late onset epilepsy' (LOE) combined with distinct neuropathological diagnostic terms were used to search PubMed until November 15, 2023. We report on the relevance of definitional aspects of LOE with implications for the diagnostic spectrum of epilepsies. The neuropathological spectrum in patients with LOE is described and includes vascular lesions, low-grade neuroepithelial neoplasms and focal cortical dysplasias (FCD). Among the latter, the frequency of the FCD subtypes appears to differ between LOE patients and those with seizure onset at a younger age. Neurodegenerative neuropathological changes in the seizure foci of LOE patients require careful interdisciplinary interpretation with respect to the differential diagnosis of primary neurodegenerative changes or epilepsy-related changes. Innate and adaptive neuroinflammation represents an important cause of LOE with intriguing therapeutic options.

Highly dynamic inflammatory and excitability transcriptional profiles in hippocampal CA1 following status epilepticus.

Transient brain insults including status epilepticus (SE) can initiate a process termed 'epileptogenesis' that results in chronic temporal lobe epilepsy. As a consequence, the entire tri-synaptic circuit of the hippocampus is fundamentally impaired. A key role in epileptogenesis has been attributed to the CA1 region as the last relay station in the hippocampal circuit and as site of aberrant plasticity, e.g. mediated by acquired channelopathies. The transcriptional profiles of the distinct hippocampal neurons are highly dynamic during epileptogenesis. Here, we aimed to elucidate the early SE-elicited mRNA signature changes and the respective upstream regulatory cascades in CA1. RNA sequencing of CA1 was performed in the mouse pilocarpine-induced SE model at multiple time points ranging from 6 to 72 h after the initial insult. Bioinformatics was used to decipher altered gene expression, signalling cascades and their corresponding cell type profiles. Robust transcriptomic changes were detected at 6 h after SE and at subsequent time points during early epileptogenesis. Major differentially expressed mRNAs encoded primarily immediate early and excitability-related gene products, as well as genes encoding immune signalling factors. Binding sites for the transcription factors Nfkb1, Spi1, Irf8, and two Runx family members, were enriched within promoters of differentially expressed genes related to major inflammatory processes, whereas the transcriptional repressors Suz12, Nfe2l2 and Rest were associated with hyperexcitability and GABA / glutamate receptor activity. CA1 quickly responds to SE by inducing transcription of genes linked to inflammation and excitation stress. Transcription factors mediating this transcriptomic switch represent targets for new highly selected, cell type and time window-specific anti-epileptogenic strategies.

Highly Oxidized Ecdysteroids from a Commercial Cyanotis arachnoidea Root Extract as Potent Blood-Brain Barrier Protective Agents.

Ecdysteroid-containing herbal extracts, commonly prepared from the roots of Cyanotis arachnoidea, are marketed worldwide as a "green" anabolic food supplement. Herein are reported the isolation and complete 1H and 13C NMR signal assignments of three new minor ecdysteroids (compounds 2-4) from this extract. Compound 4 was identified as a possible artifact that gradually forms through the autoxidation of calonysterone. The compounds tested demonstrated a significant protective effect on the blood-brain barrier endothelial cells against oxidative stress or inflammation at a concentration of 1 µM. Based on these results, minor ecdysteroids present in food supplements may offer health benefits in various neurodegenerative disease states.