Abstract
Caloric restriction (CR) has anti-epileptic effects in different animal models, at least partially due to inhibition of the mechanistic or mammalian target of rapamycin (mTOR) signaling pathway. Adenosine monophosphate-activated protein kinase (AMPK) inhibits mTOR cascade function if energy levels are low. Since hyper-activation of mTOR participates in epilepsy, its inhibition results in beneficial anti-convulsive effects. A way to attain this is to activate AMPK with metformin. The effects of metformin, alone or combined with CR, on the electrical kindling epilepsy model and the mTOR cascade in the hippocampus and the neocortex were studied. Combined metformin plus CR beneficially affected many kindling aspects, especially those relating to generalized convulsive seizures. Therefore, metformin plus CR could decrease measures of epileptic activity in patients with generalized convulsive seizures. Patients that are obese, overweight or that have metabolic syndrome in addition to having an epileptic disease are an ideal population for clinical trials to test the effectiveness of metformin plus CR.
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Abbreviations
- AD:
-
After-discharge
- AL:
-
Ad libitum fed group
- AM:
-
Ad libitum fed group metformin-treated
- AMPK:
-
Adenosine monophosphate-activated protein kinase
- AMPKα1 :
-
Adenosine monophosphate-activated protein kinase alpha 1 catalytic subunit gene
- AMPKα2 :
-
Adenosine monophosphate-activated protein kinase alpha 2 catalytic subunit gene
- ANOVA:
-
Analysis of variance
- β-HB:
-
β-Hydroxybutyrate
- CM:
-
Group subjected to caloric restriction and metformin-treated
- CR:
-
Caloric restriction
- Cx:
-
Neocortex
- ed:
-
Experimental day
- Hp:
-
Hippocampus
- mTOR:
-
Mechanistic target of rapamycin
- MTOR :
-
Mechanistic target of rapamycin gene
- mTORC1:
-
Mechanistic target of rapamycin complex 1
- pAMPK:
-
Phosphorylated adenosine monophosphate-activated protein kinase
- pd:
-
Postnatal day
- PKB:
-
Protein kinase B
- pPKB:
-
Phosphorylated protein kinase B
- pS6:
-
Phosphorylated ribosomal protein S6
- S6:
-
Ribosomal protein S6
- S6K :
-
Ribosomal S6 kinase gene
- TSC1 :
-
Tuberous sclerosis 1 gene
- TSC2 :
-
Tuberous sclerosis 2 gene
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Acknowledgements
We thank Reyna Hernández Morales, María de la Luz Correa Gómez, and Patricia Zárate Grajales for their technical assistance.
Funding
This study was supported by the Instituto Nacional de Pediatría.
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MdelCRO, VCR, and DCG were responsible for performing all the experimental procedures, as well as obtaining all the resulting data and contributing to its analysis. CPT, KGCA, and BVPF contributed to the plan and design of the experiments, as well as to the writing and revising of the manuscript. BVPF performed the original plan and design of the experiments, contributed to the analysis of all the resulting data, as well as to the writing and revising of the manuscript.
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10571_2018_611_MOESM1_ESM.tif
Representative electrographic recordings taken from one animal from each of the groups: fed ad libitum (AL), fed ad libitum + metformin (AM) or subjected to caloric restriction + metformin (CM). Epileptic activity is observed, characterized by spikes of great amplitude and low frequency. The horizontal lines under the electrographic records indicate the AD duration. Scale bar 1 s. Supplementary material 1 (TIF 4157 KB)
10571_2018_611_MOESM2_ESM.tif
Taqman® gene expression assays that were used to perform the real-time PCR. The catalog number, gene, NCBI reference sequences and amplicon lengths are shown. Supplementary material 2 (TIF 4625 KB)
10571_2018_611_MOESM3_ESM.pdf
Representative full western blots showing phosphorylated (p) and total AMPK and PKB in the neocortex (Cx) and hippocampus (Hp) of rats fed ad libitum + metformin (AM) or subjected to 15 % caloric restriction + metformin (CM). A protein ladder showing the relative molecular weight (in kilodaltons) is shown to the left of the bands, while the groups and brain regions are shown above the bands. Supplementary material 3 (PDF 17 KB)
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Rubio Osornio, M.C., Custodio Ramírez, V., Calderón Gámez, D. et al. Metformin Plus Caloric Restriction Show Anti-epileptic Effects Mediated by mTOR Pathway Inhibition. Cell Mol Neurobiol 38, 1425–1438 (2018). https://doi.org/10.1007/s10571-018-0611-8
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DOI: https://doi.org/10.1007/s10571-018-0611-8