Inhibiting astrocyte calcium dynamics terminates status epilepticus via wireless septal stimulation

Area of Science:

• Neuroscience
• Cellular Biology
• Epilepsy Research

Background:

• Status epilepticus (SE) is a medical emergency with poorly understood cellular and circuit mechanisms.
• Developing effective anti-SE strategies is crucial for patient outcomes.

Purpose of the Study:

• To investigate distinct astrocytic calcium (Ca2+) activity patterns during generalized seizures (GS) and focal seizures (FS).
• To evaluate the efficacy of micrometer-scale wireless electrical stimulation (WES) targeting the medial septum and ventral diagonal band of Broca (MS/vDB) for SE termination and suppression.
• To elucidate the cellular mechanisms underlying WES efficacy in SE treatment.

Main Methods:

• Observation of astrocytic Ca2+ activity patterns during SE.
• Application of micrometer-scale wireless electrical stimulation (WES) to the MS/vDB.
• Assessment of SE termination and suppression.
• Analysis of MS/vDB GABAergic neuron activation.
• Investigation of effects on the CA3 astrocyte-pyramidal neuron microcircuit.
• Evaluation of WES efficacy in a pilocarpine-induced chronic seizure model.

Main Results:

• Distinct astrocytic Ca2+ activity patterns were observed: synchronized activity in CA3 and contralateral S1 during GS, and desynchronization during FS.
• WES targeting MS/vDB effectively terminated SE and suppressed abnormal astrocytic Ca2+ activity, comparable to deep brain stimulation (DBS).
• WES-induced suppression was linked to MS/vDB GABAergic neuron activation, which reduced calcium dynamics in the CA3 astrocyte-pyramidal neuron microcircuit.
• WES of MS/vDB also suppressed chronic spontaneous seizures induced by pilocarpine within 10 days.

Conclusions:

• Astrocytic activity patterns during SE are divergent depending on seizure type.
• WES of the MS/vDB represents a promising, advanced therapeutic strategy for effectively suppressing SE and chronic seizures.