Ketogenic diet-produced β-hydroxybutyric acid accumulates brain GABA and increases GABA/glutamate ratio to inhibit epilepsy.
Level 5 - mechanism / opinion, no new human data
Preclinical animal and in vitro mechanistic laboratory study
PubMed 38346975 · doi:10.1038/s41421-023-00636-x
What was done
Researchers investigated the cellular and metabolic mechanisms underlying the antiepileptic effects of the ketogenic diet and its ketone bodies using a pentetrazol-induced epilepsy mouse model. They evaluated the effects of the ketogenic diet and direct β-hydroxybutyrate (BHB) administration on seizure susceptibility, histone acetylation, enzymatic pathways (HDAC1/2, SIRT4, GAD1, glutamate dehydrogenase), and brain neurotransmitter levels (GABA and glutamate).
What was found
Both the ketogenic diet and BHB administration ameliorated pentetrazol-induced seizures in mice. Mechanistically, BHB, but not other ketone bodies, inhibited HDAC1/HDAC2, increased H3K27 acetylation, and transcriptionally upregulated SIRT4 and GAD1. BHB-induced SIRT4 de-carbamylated and inactivated glutamate dehydrogenase to preserve glutamate for GABA synthesis, while GAD1 upregulation elevated the brain GABA/glutamate ratio to inhibit neuronal excitation. Relief of epilepsy by BHB required high GABA levels and an elevated GABA/glutamate ratio. The abstract reported no specific numerical values or effect sizes.
Why it matters
This study defines an epigenetic and metabolic pathway by which BHB increases the brain GABA/glutamate ratio to suppress seizures in mice. It suggests that direct BHB supplementation could potentially serve as a targeted, less restrictive alternative to the ketogenic diet for epilepsy management.
Limits
Findings are limited to preclinical chemical-induction mouse models; translatability to human clinical epilepsy is not established. The abstract does not report animal sample sizes, effect sizes, dosages, or statistical certainty values. Non-chemical seizure models and long-term safety of exogenous BHB administration were not evaluated.
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