Repeated seizure-induced brainstem neuroinflammation contributes to post-ictal ventilatory control dysfunction

Area of Science:

• Neuroscience
• Respiratory Physiology
• Inflammation Research

Background:

• Epilepsy increases risk of cardiorespiratory suppression and SUDEP.
• Neuroinflammation, involving microglia and astrocytes, is linked to seizures.
• Kcnj16 knockout rats exhibit SUDEP features, including post-ictal ventilatory suppression.

Purpose of the Study:

• To investigate if repeated seizures induce neuroinflammation in brainstem respiratory control centers.
• To determine the functional role of neuroinflammation in seizure-induced physiological changes and mortality.

Main Methods:

• Audiogenic seizures were induced daily in Kcnj16 knockout rats for up to 10 days.
• Cytokine arrays and microglial activation markers (IBA-1) were analyzed in brainstem regions (preBötC/NA, BötC, RMg).
• Rats were treated with anakinra (IL-1R antagonist) or ketoprofen (COX inhibitor) to assess effects on breathing and mortality.

Main Results:

• Repeated seizures increased IL-1α and IL-1ß in the preBötC/NA region.
• Microglial activation (increased cell count, area, volume) was observed in the preBötC/NA.
• Anakinra partially mitigated post-ictal ventilatory suppression but not mortality; ketoprofen worsened suppression but prevented mortality.

Conclusions:

• Repeated seizures induce neuroinflammation and microglial activation in the brainstem's respiratory control network.
• Inflammatory pathways, particularly IL-1 and COX signaling, differentially influence seizure-induced respiratory dysfunction and mortality.
• Targeting specific inflammatory mediators may offer therapeutic strategies for epilepsy-related complications.