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Iyer SH, Hinman JE, Warren T, Matthews SA, Simeone TA, Simeone KA. Altered ventilatory responses to hypercapnia-hypoxia challenges in a preclinical SUDEP model involve orexin neurons. Neurobiol Dis 2024; 199:106592. [PMID: 38971479 DOI: 10.1016/j.nbd.2024.106592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 06/25/2024] [Accepted: 07/02/2024] [Indexed: 07/08/2024] Open
Abstract
Failure to recover from repeated hypercapnia and hypoxemia (HH) challenges caused by severe GCS and postictal apneas may contribute to sudden unexpected death in epilepsy (SUDEP). Our previous studies found orexinergic dysfunction contributes to respiratory abnormalities in a preclinical model of SUDEP, Kcna1-/- mice. Here, we developed two gas challenges consisting of repeated HH exposures and used whole body plethysmography to determine whether Kcna1-/- mice have detrimental ventilatory responses. Kcna1-/- mice exhibited an elevated ventilatory response to a mild repeated hypercapnia-hypoxia (HH) challenge compared to WT. Moreover, 71% of Kcna1-/- mice failed to survive a severe repeated HH challenge, whereas all WT mice recovered. We next determined whether orexin was involved in these differences. Pretreating Kcna1-/- mice with a dual orexin receptor antagonist rescued the ventilatory response during the mild challenge and all subjects survived the severe challenge. In ex vivo extracellular recordings in the lateral hypothalamus of coronal brain slices, we found reducing pH either inhibits or stimulates putative orexin neurons similar to other chemosensitive neurons; however, a significantly greater percentage of putative orexin neurons from Kcna1-/-mice were stimulated and the magnitude of stimulation was increased resulting in augmentation of the calculated chemosensitivity index relative to WT. Collectively, our data suggest that increased chemosensitive activity of orexin neurons may be pathologic in the Kcna1-/- mouse model of SUDEP, and contribute to elevated ventilatory responses. Our preclinical data suggest that those at high risk for SUDEP may be more sensitive to HH challenges, whether induced by seizures or other means; and the depth and length of the HH exposure could dictate the probability of survival.
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Affiliation(s)
- Shruthi H Iyer
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Jillian E Hinman
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Ted Warren
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Stephanie A Matthews
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Timothy A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA.
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Westmark PR, Swietlik TJ, Runde E, Corsiga B, Nissan R, Boeck B, Granger R, Jennings E, Nebbia M, Thauwald A, Lyon G, Maganti RK, Westmark CJ. Adult Inception of Ketogenic Diet Therapy Increases Sleep during the Dark Cycle in C57BL/6J Wild Type and Fragile X Mice. Int J Mol Sci 2024; 25:6679. [PMID: 38928388 PMCID: PMC11203515 DOI: 10.3390/ijms25126679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/10/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024] Open
Abstract
Sleep problems are a significant phenotype in children with fragile X syndrome. Our prior work assessed sleep-wake cycles in Fmr1KO male mice and wild type (WT) littermate controls in response to ketogenic diet therapy where mice were treated from weaning (postnatal day 18) through study completion (5-6 months of age). A potentially confounding issue with commencing treatment during an active period of growth is the significant reduction in weight gain in response to the ketogenic diet. The aim here was to employ sleep electroencephalography (EEG) to assess sleep-wake cycles in mice in response to the Fmr1 genotype and a ketogenic diet, with treatment starting at postnatal day 95. EEG results were compared with prior sleep outcomes to determine if the later intervention was efficacious, as well as with published rest-activity patterns to determine if actigraphy is a viable surrogate for sleep EEG. The data replicated findings that Fmr1KO mice exhibit sleep-wake patterns similar to wild type littermates during the dark cycle when maintained on a control purified-ingredient diet but revealed a genotype-specific difference during hours 4-6 of the light cycle of the increased wake (decreased sleep and NREM) state in Fmr1KO mice. Treatment with a high-fat, low-carbohydrate ketogenic diet increased the percentage of NREM sleep in both wild type and Fmr1KO mice during the dark cycle. Differences in sleep microstructure (length of wake bouts) supported the altered sleep states in response to ketogenic diet. Commencing ketogenic diet treatment in adulthood resulted in a 15% (WT) and 8.6% (Fmr1KO) decrease in body weight after 28 days of treatment, but not the severe reduction in body weight associated with starting treatment at weaning. We conclude that the lack of evidence for improved sleep during the light cycle (mouse sleep time) in Fmr1KO mice in response to ketogenic diet therapy in two studies suggests that ketogenic diet may not be beneficial in treating sleep problems associated with fragile X and that actigraphy is not a reliable surrogate for sleep EEG in mice.
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Affiliation(s)
- Pamela R. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Timothy J. Swietlik
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Ethan Runde
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Brian Corsiga
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Rachel Nissan
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Brynne Boeck
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Ricky Granger
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Erica Jennings
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Maya Nebbia
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Andrew Thauwald
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Greg Lyon
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Rama K. Maganti
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Cara J. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
- Molecular Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
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Iyer SH, Yeh MY, Netzel L, Lindsey MG, Wallace M, Simeone KA, Simeone TA. Dietary and Metabolic Approaches for Treating Autism Spectrum Disorders, Affective Disorders and Cognitive Impairment Comorbid with Epilepsy: A Review of Clinical and Preclinical Evidence. Nutrients 2024; 16:553. [PMID: 38398876 PMCID: PMC10893388 DOI: 10.3390/nu16040553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 02/09/2024] [Accepted: 02/14/2024] [Indexed: 02/25/2024] Open
Abstract
Epilepsy often occurs with other neurological disorders, such as autism, affective disorders, and cognitive impairment. Research indicates that many neurological disorders share a common pathophysiology of dysfunctional energy metabolism, neuroinflammation, oxidative stress, and gut dysbiosis. The past decade has witnessed a growing interest in the use of metabolic therapies for these disorders with or without the context of epilepsy. Over one hundred years ago, the high-fat, low-carbohydrate ketogenic diet (KD) was formulated as a treatment for epilepsy. For those who cannot tolerate the KD, other diets have been developed to provide similar seizure control, presumably through similar mechanisms. These include, but are not limited to, the medium-chain triglyceride diet, low glycemic index diet, and calorie restriction. In addition, dietary supplementation with ketone bodies, polyunsaturated fatty acids, or triheptanoin may also be beneficial. The proposed mechanisms through which these diets and supplements work to reduce neuronal hyperexcitability involve normalization of aberrant energy metabolism, dampening of inflammation, promotion of endogenous antioxidants, and reduction of gut dysbiosis. This raises the possibility that these dietary and metabolic therapies may not only exert anti-seizure effects, but also reduce comorbid disorders in people with epilepsy. Here, we explore this possibility and review the clinical and preclinical evidence where available.
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Affiliation(s)
| | | | | | | | | | | | - Timothy A. Simeone
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA; (S.H.I.); (K.A.S.)
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Kodirov SA. Adam, amigo, brain, and K channel. Biophys Rev 2023; 15:1393-1424. [PMID: 37975011 PMCID: PMC10643815 DOI: 10.1007/s12551-023-01163-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 09/28/2023] [Indexed: 11/19/2023] Open
Abstract
Voltage-dependent K+ (Kv) channels are diverse, comprising the classical Shab - Kv2, Shaker - Kv1, Shal - Kv4, and Shaw - Kv3 families. The Shaker family alone consists of Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv1.5, Kv1.6, and Kv1.7. Moreover, the Shab family comprises two functional (Kv2.1 and Kv2.2) and several "silent" alpha subunits (Kv2.3, Kv5, Kv6, Kv8, and Kv9), which do not generate K current. However, e.g., Kv8.1, via heteromerization, inhibits outward currents of the same family or even that of Shaw. This property of Kv8.1 is similar to those of designated beta subunits or non-selective auxiliary elements, including ADAM or AMIGO proteins. Kv channels and, in turn, ADAM may modulate the synaptic long-term potentiation (LTP). Prevailingly, Kv1.1 and Kv1.5 are attributed to respective brain and heart pathologies, some of which may occur simultaneously. The aforementioned channel proteins are apparently involved in several brain pathologies, including schizophrenia and seizures.
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Affiliation(s)
- Sodikdjon A. Kodirov
- Department of Biological Sciences, University of Texas at Brownsville, Brownsville, TX 78520 USA
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint Petersburg, Russia
- Instituto de Medicina Molecular, Universidade de Lisboa, 1649-028 Lisbon, Portugal
- Almazov Federal Heart, Blood and Endocrinology Centre, Saint Petersburg, 197341 Russia
- Institute for Physiology and Pathophysiology, Johannes Kepler University, Linz, Austria
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Westmark PR, Gholston AK, Swietlik TJ, Maganti RK, Westmark CJ. Ketogenic Diet Affects Sleep Architecture in C57BL/6J Wild Type and Fragile X Mice. Int J Mol Sci 2023; 24:14460. [PMID: 37833907 PMCID: PMC10572443 DOI: 10.3390/ijms241914460] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 10/15/2023] Open
Abstract
Nearly half of children with fragile X syndrome experience sleep problems including trouble falling asleep and frequent nighttime awakenings. The goals here were to assess sleep-wake cycles in mice in response to Fmr1 genotype and a dietary intervention that reduces hyperactivity. Electroencephalography (EEG) results were compared with published rest-activity patterns to determine if actigraphy is a viable surrogate for sleep EEG. Specifically, sleep-wake patterns in adult wild type and Fmr1KO littermate mice were recorded after EEG electrode implantation and the recordings manually scored for vigilance states. The data indicated that Fmr1KO mice exhibited sleep-wake patterns similar to wild type littermates when maintained on a control purified ingredient diet. Treatment with a high-fat, low-carbohydrate ketogenic diet increased the percentage of non-rapid eye movement (NREM) sleep in both wild type and Fmr1KO mice during the dark cycle, which corresponded to decreased activity levels. Treatment with a ketogenic diet flattened diurnal sleep periodicity in both wild type and Fmr1KO mice. Differences in several sleep microstructure outcomes (number and length of sleep and wake bouts) supported the altered sleep states in response to a ketogenic diet and were correlated with altered rest-activity cycles. While actigraphy may be a less expensive, reduced labor surrogate for sleep EEG during the dark cycle, daytime resting in mice did not correlate with EEG sleep states.
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Affiliation(s)
- Pamela R. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Aaron K. Gholston
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
- Molecular Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
| | - Timothy J. Swietlik
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Rama K. Maganti
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Cara J. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
- Molecular Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
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Kostansek JA, Latona GJ, Heruye SH, Matthews S, Bockman CS, Simeone KA, Simeone TA. Orexin receptors regulate hippocampal sharp wave-ripple complexes in ex vivo slices. Eur J Pharmacol 2023; 950:175763. [PMID: 37146705 PMCID: PMC10311575 DOI: 10.1016/j.ejphar.2023.175763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/13/2023] [Accepted: 05/02/2023] [Indexed: 05/07/2023]
Abstract
Orexin is a neuromodulatory peptide produced by lateral hypothalamic orexin neurons and binds to G-protein-coupled orexin-1 receptor and orexin-2 receptors. Whether orexin modulates learning and memory is not fully understood. Orexin has biphasic effects on learning and memory: promoting learning and memory at homeostatic levels and inhibiting at supra- and sub-homeostatic levels. Hippocampal sharp wave-ripples encode memory information and are essential for memory consolidation and retrieval. The role of orexin on sharp wave-ripples in hippocampal CA1 remains unknown. Here, we used multi-electrode array recordings in acute ex vivo hippocampal slices to determine the effects of orexin receptor antagonists on sharp wave-ripples. Bath-application of either the orexin-1 receptor antagonist N-(2-Methyl-6-benzoxazolyl)-N'-1,5-naphthyridin-4-yl urea (SB-334867) or the orexin-2 receptor antagonist N-Ethyl-2-[(6-methoxy-3-pyridinyl)[(2-methylphenyl)sulfonyl]amino]-N-(3-pyridinylmethyl)-acetamide (EMPA) reduced sharp wave and ripple incidence, sharp wave amplitude, and sharp wave duration. SB-334867 and EMPA effects on sharp wave amplitude and duration were equivalent, whereas EMPA exhibited a greater reduction of sharp wave and ripple incidence. EMPA also increased ripple duration, whereas SB-334867 had no effect. Inhibition of both orexin receptors with a dual orexin receptor antagonist N-[1,1'-Biphenyl]-2-yl-1-[2-[(1-methyl-1H-benzimidazol-2-yl)thio]acetyl-2-pyrrolidinedicarboxamide (TCS-1102) had effects similar to EMPA, however, sharp wave amplitude and duration were unaffected. Region-specific expression of orexin receptors suggests orexin may regulate sharp wave generation in CA3, dentate gyrus-mediated sharp wave modification, sharp wave propagation to CA1, and local ripple emergence in CA1. Our study indicates an orexin contribution to hippocampal sharp wave-ripple complexes and suggests a mechanism by which sub-homeostatic concentrations of orexin may inhibit learning and memory function.
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Affiliation(s)
- Joseph A Kostansek
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA.
| | - Gavin J Latona
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Segewkal H Heruye
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Stephanie Matthews
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Charles S Bockman
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Kristina A Simeone
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA
| | - Timothy A Simeone
- Creighton University, School of Medicine, Department of Pharmacology & Neuroscience, Omaha, NE, 68174, USA.
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Moriyama H, Nomura S, Imoto H, Oka F, Maruta Y, Mori N, Fujii N, Suzuki M, Ishihara H. Suppressive effects of a transient receptor potential melastatin 8 (TRPM8) agonist on hyperthermia-induced febrile seizures in infant mice. Front Pharmacol 2023; 14:1138673. [PMID: 36969879 PMCID: PMC10033885 DOI: 10.3389/fphar.2023.1138673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/24/2023] [Indexed: 03/11/2023] Open
Abstract
Background: Febrile seizures (FSs) are the most frequent type of seizures in infancy and childhood. Epileptiform discharges (EDs) on electroencephalogram at the time of first FS recurrence can increase the risk of epilepsy development. Therefore, inhibition of EDs is important. Recently, WS-3, a transient receptor potential melastatin 8 (TRPM8) agonist, reportedly suppressed penicillin G-induced cortical-focal EDs. However, the effects of TRPM8 agonists on FSs remain unknown. In this study, we aimed to clarify the effects of the TRPM8 agonist, and the absence of TRPM8 channels, on hyperthermia-induced FS by analyzing the fast ripple band.Methods: Hyperthermia (43°C for 30 min) induced by a heating pad caused FSs in postnatal day 7 wild-type (WT) and TRPM8 knockout (TRPM8KO) mice. FSs were defined as EDs occurring during behavioral seizures involving hindlimb clonus and loss of the righting reflex. Mice were injected with 1% dimethyl sulfoxide or 1 mM WS-3 20 min before the onset of hyperthermia, and electroencephalograms; movies; and rectal, brain and heating pad temperatures were recorded.Results: In wild-type mice, WS-3 reduced the fast ripple amplitude in the first FS without changing rectal and brain temperature thresholds. In contrast, the anti-FS effect induced by the TRPM8 agonist was not observed in TRPM8KO mice and, compared with wild-type mice, TRPM8 deficiency lowered the rectal and brain temperature thresholds for FSs, exacerbated the fast ripple amplitude, and prolonged the duration of the initial FS induced by hyperthermia.Conclusion: Our findings suggest that TRPM8 agonists can be used to treat hyperthermia-induced FSs.
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Affiliation(s)
- Hiroshi Moriyama
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
- *Correspondence: Hiroshi Moriyama,
| | - Sadahiro Nomura
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
- Epilepsy Center, Yamaguchi University Hospital, Ube, Yamaguchi, Japan
| | - Hirochika Imoto
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
- Epilepsy Center, Yamaguchi University Hospital, Ube, Yamaguchi, Japan
| | - Fumiaki Oka
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
| | - Yuichi Maruta
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
| | - Naomasa Mori
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
| | - Natsumi Fujii
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
| | - Michiyasu Suzuki
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
| | - Hideyuki Ishihara
- Departments of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
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Heruye SH, Warren TJ, Kostansek IV JA, Draves SB, Matthews SA, West PJ, Simeone KA, Simeone TA. Ascorbic Acid Reduces Neurotransmission, Synaptic Plasticity, and Spontaneous Hippocampal Rhythms in In Vitro Slices. Nutrients 2022; 14:nu14030613. [PMID: 35276972 PMCID: PMC8839482 DOI: 10.3390/nu14030613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 12/26/2022] Open
Abstract
Ascorbic acid (AA; a.k.a. vitamin C) is well known for its cellular protection in environments of high oxidative stress. Even though physiological concentrations of AA in the brain are significant (0.2–10 mM), surprisingly little is known concerning the role of AA in synaptic neurotransmission under normal, non-disease state conditions. Here, we examined AA effects on neurotransmission, plasticity and spontaneous network activity (i.e., sharp waves and high frequency oscillations; SPW-HFOs), at the synapse between area 3 and 1 of the hippocampal cornu ammonis region (CA3 and CA1) using an extracellular multi-electrode array in in vitro mouse hippocampal slices. We found that AA decreased evoked field potentials (fEPSPs, IC50 = 0.64 mM) without affecting V50s or paired pulse facilitation indicating normal neurotransmitter release mechanisms. AA decreased presynaptic fiber volleys but did not change fiber volley-to-fEPSP coupling, suggesting reduced fEPSPs resulted from decreased fiber volleys. Inhibitory effects were also observed in CA1 stratum pyramidale where greater fEPSPs were required for population spikes in the presence of AA suggesting an impact on the intrinsic excitability of neurons. Other forms of synaptic plasticity and correlates of memory (i.e., short- and long-term potentiation) were also significantly reduced by AA as was the incidence of spontaneous SPW-HFOs. AA decreased SPW amplitude with a similar IC50 as fEPSPs (0.65 mM). Overall, these results indicate that under normal conditions AA significantly regulates neurotransmission, plasticity, and network activity by limiting excitability. Thus, AA may participate in refinement of signal processing and memory formation, as well as protecting against pathologic excitability.
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Affiliation(s)
- Segewkal H. Heruye
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Ted J. Warren
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Joseph A. Kostansek IV
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Samantha B. Draves
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Stephanie A. Matthews
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Peter J. West
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT 84112, USA;
| | - Kristina A. Simeone
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Timothy A. Simeone
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
- Correspondence:
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Simeone KA, Wilke JC, Matthews SA, Simeone TA, Rho JM. Ketogenic diet-mediated seizure reduction preserves CA1 cell numbers in epileptic Kcna1-null mice: An unbiased stereological assessment. Epilepsia 2021; 62:e123-e128. [PMID: 34231878 DOI: 10.1111/epi.16983] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 06/14/2021] [Accepted: 06/14/2021] [Indexed: 10/20/2022]
Abstract
There is growing evidence for the disease-modifying potential of metabolic therapies, including the ketogenic diet (KD), which is used to treat medically intractable epilepsy. However, it remains unclear whether the KD exerts direct effects on histopathological changes in epileptic brain, or whether the changes are a consequence of diet-induced reduction in seizure activity. Here, we used unbiased stereological techniques to quantify the seizure-induced reduction in cell number in the CA1 region of the hippocampus of epileptic Kcna1-null mice and compared the effects of the KD with that of phenobarbital (PB), a widely employed anti-seizure drug. Our data suggest that the anti-seizure activity of the KD or PB was similar. However, CA1 cell numbers of KD-treated hippocampi were not significantly different from those seen in wild-type (WT) mice, whereas CA1 cell counts in standard diet and PB-treated Kcna1-null mice were 23% and 31% lower than WT animals, respectively. These results support the notion that structural protection of cells may involve more than seizure attenuation, and that the KD engages mechanisms that also promote or restore hippocampal morphological integrity.
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Affiliation(s)
- Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Julianne C Wilke
- Department of Pediatrics, University of California San Diego, San Diego, CA, USA.,Rady Children's Hospital San Diego, San Diego, CA, USA
| | - Stephanie A Matthews
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Timothy A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Jong M Rho
- Department of Pediatrics, University of California San Diego, San Diego, CA, USA.,Rady Children's Hospital San Diego, San Diego, CA, USA.,Department of Neurosciences, University of California San Diego, San Diego, CA, USA
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10
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Ketogenic diets and the nervous system: a scoping review of neurological outcomes from nutritional ketosis in animal studies. Nutr Res Rev 2021; 35:268-281. [PMID: 34180385 DOI: 10.1017/s0954422421000214] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES Ketogenic diets have reported efficacy for neurological dysfunctions; however, there are limited published human clinical trials elucidating the mechanisms by which nutritional ketosis produces therapeutic effects. The purpose of this present study was to investigate animal models that report variations in nervous system function by changing from a standard animal diet to a ketogenic diet, synthesise these into broad themes, and compare these with mechanisms reported as targets in pain neuroscience to inform human chronic pain trials. METHODS An electronic search of seven databases was conducted in July 2020. Two independent reviewers screened studies for eligibility, and descriptive outcomes relating to nervous system function were extracted for a thematic analysis, then synthesised into broad themes. RESULTS In total, 170 studies from eighteen different disease models were identified and grouped into fourteen broad themes: alterations in cellular energetics and metabolism, biochemical, cortical excitability, epigenetic regulation, mitochondrial function, neuroinflammation, neuroplasticity, neuroprotection, neurotransmitter function, nociception, redox balance, signalling pathways, synaptic transmission and vascular supply. DISCUSSION The mechanisms presented centred around the reduction of inflammation and oxidative stress as well as a reduction in nervous system excitability. Given the multiple potential mechanisms presented, it is likely that many of these are involved synergistically and undergo adaptive processes within the human body, and controlled animal models that limit the investigation to a particular pathway in isolation may reach differing conclusions. Attention is required when translating this information to human chronic pain populations owing to the limitations outlined from the animal research.
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11
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Simeone TA, Heruye SH, Kostansek JA, Yeh MY, Matthews SA, Samson KK, Simeone KA. Carbamazepine Reduces Sharp Wave-Ripple Complexes and Exerts Synapse-Specific Inhibition of Neurotransmission in Ex Vivo Hippocampal Slices. Brain Sci 2021; 11:brainsci11060787. [PMID: 34203601 PMCID: PMC8232098 DOI: 10.3390/brainsci11060787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 12/04/2022] Open
Abstract
Higher therapeutic concentrations of the antiseizure medication carbamazepine (CBZ) are associated with cognitive side effects. Hippocampal sharp wave-ripple complexes (SPW-Rs) are proposed to participate in memory consolidation during periods of quiet and slow-wave sleep. SPW-Rs are generated in the CA3 region and are regulated by multiple synaptic inputs. Here, we used a multi-electrode array to determine the effects of CBZ on SPW-Rs and synaptic transmission at multiple hippocampal synapses. Our results demonstrate that CBZ reduced SPW-Rs at therapeutically relevant concentrations (IC50 = 37 μM) and altered the core characteristics of ripples, important for information processing and consolidation. Moreover, CBZ inhibited neurotransmission in a synapse-specific manner. CBZ inhibition was most potent at the medial-perforant-path-to-CA3 and mossy-fiber-to-CA3 synapses (IC50s ~ 30 and 60 μM, respectively) and least potent at medial-perforant-path-to-dentate granule cell synapses (IC50 ~ 120 μM). These results suggest that the synapse-specific CBZ inhibition of neurotransmission reduces SPW-Rs and that the CBZ inhibition of SPW-Rs may underlie the cognitive impairments observed with therapeutic doses of CBZ.
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12
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Johnson A, Grove RA, Madhavan D, Boone CHT, Braga C, Kyllo H, Samson K, Simeone K, Simeone T, Helikar T, Hanson CK, Adamec J. Changes in lipid profiles of epileptic mouse model. Metabolomics 2020; 16:106. [PMID: 33021695 PMCID: PMC10614666 DOI: 10.1007/s11306-020-01729-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 09/23/2020] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Approximately 1% of the world's population is impacted by epilepsy, a chronic neurological disorder characterized by seizures. One-third of epileptic patients are resistant to AEDs, or have medically refractory epilepsy (MRE). One non-invasive treatment that exists for MRE includes the ketogenic diet, a high-fat, low-carbohydrate diet. Despite the KD's success in seizure attenuation, it has a few risks and its mechanisms remain poorly understood. The KD has been shown to improve metabolism and mitochondrial function in epileptic phenotypes. Potassium channels have implications in epileptic conditions as they have dual roles as metabolic sensors and control neuronal excitation. OBJECTIVES The goal of this study was to explore changes in the lipidome in hippocampal and cortical tissue from Kv1.1-KO model of epilepsy. METHODS FT-ICR/MS analysis was utilized to examine nonpolar metabolome of cortical and hippocampal tissue isolated from a Kv1.1 channel knockout mouse model of epilepsy (n = 5) and wild-type mice (n = 5). RESULTS Distinct metabolic profiles were observed, significant (p < 0.05) features in hippocampus often being upregulated (FC ≥ 2) and the cortex being downregulated (FC ≤ 0.5). Pathway enrichment analysis shows lipid biosynthesis was affected. Partition ratio analysis revealed that the ratio of most metabolites tended to be increased in Kv1.1-/-. Metabolites in hippocampal tissue were commonly upregulated, suggesting seizure initiation in the hippocampus. Aberrant mitochondrial function is implicated by the upregulation of cardiolipin, a common component in the mitochondrial membrane. CONCLUSION Generally, our study finds that the lipidome is changed in the hippocampus and cortex in response to Kv1.1-KO indicating changes in membrane structural integrity and synaptic transmission.
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Affiliation(s)
- Alicia Johnson
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Ryan A Grove
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Deepak Madhavan
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Cory H T Boone
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Camila Braga
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Hannah Kyllo
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Kaeli Samson
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Kristina Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Timothy Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Tomas Helikar
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Corrine K Hanson
- College of Allied Health Professions, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jiri Adamec
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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13
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Granados-Rojas L, Jerónimo-Cruz K, Juárez-Zepeda TE, Tapia-Rodríguez M, Tovar AR, Rodríguez-Jurado R, Carmona-Aparicio L, Cárdenas-Rodríguez N, Coballase-Urrutia E, Ruíz-García M, Durán P. Ketogenic Diet Provided During Three Months Increases KCC2 Expression but Not NKCC1 in the Rat Dentate Gyrus. Front Neurosci 2020; 14:673. [PMID: 32733191 PMCID: PMC7358437 DOI: 10.3389/fnins.2020.00673] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 06/02/2020] [Indexed: 01/01/2023] Open
Abstract
Ketogenic diet, a high fat and low carbohydrate diet, has been used as a non-pharmacological treatment in refractory epilepsy since 1920. In recent years, it has demonstrated to be effective in the treatment of numerous neurological and non-neurological diseases. Some neurological and neuropsychiatric disorders are known to be caused by gamma-aminobutyric acid (GABA)-mediated neurotransmission dysfunction. The strength and polarity of GABA-mediated neurotransmission are determined by the intracellular chloride concentration, which in turn is regulated by cation-chloride cotransporters NKCC1 and KCC2. Currently, it is unknown if the effect of ketogenic diet is due to the modulation of these cotransporters. Thus, we analyzed the effect of a ketogenic diet on the cation-chloride cotransporters expression in the dentate gyrus. We estimated the total number of NKCC1 immunoreactive (NKCC1-IR) neuronal and glial cells by stereology and determined KCC2 labeling intensity by densitometry in the molecular and granule layers as well as in the hilus of dentate gyrus of rats fed with normal or ketogenic diet for 3 months. The results indicated that ketogenic diet provided during 3 months increased KCC2 expression, but not NKCC1 in the dentate gyrus of the rat. The significant increase of KCC2 expression could explain, at least in part, the beneficial effect of ketogenic diet in the diseases where the GABAergic system is altered by increasing its inhibitory efficiency.
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Affiliation(s)
| | - Karina Jerónimo-Cruz
- Laboratorio de Neurociencias, Instituto Nacional de Pediatría, Mexico City, Mexico
| | | | - Miguel Tapia-Rodríguez
- Unidad de Microscopía, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Armando R Tovar
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | | | | | | | | | - Matilde Ruíz-García
- Servicio de Neurología, Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Pilar Durán
- Laboratorio de Biología Animal Experimental, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
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14
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Ren Y, Chang J, Li C, Jia C, Li P, Wang Y, Chu XP. The Effects of Ketogenic Diet Treatment in Kcna1-Null Mouse, a Model of Sudden Unexpected Death in Epilepsy. Front Neurol 2019; 10:744. [PMID: 31354612 PMCID: PMC6635472 DOI: 10.3389/fneur.2019.00744] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/26/2019] [Indexed: 12/16/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a leading cause of abrupt death in patient with epilepsy. It represents 5-30% of all rapid deaths in individuals with epilepsy. Ketogenic diet (KD) has been used in clinic for treatment of epilepsy for many decades. However, the cellular and molecular mechanisms underlying the SUDEP and the relationship between KD and SUDEP remain uncertain. Kcna1-null (Kcna1-/-) mouse, an animal model of SUDEP, is frequently used to study mechanisms underlying SUDEP. The current mini-review focus on risk factors for SUDEP and their relationship with KD treatment in Kcna1-/- mice. Emerging data suggest that factors including seizure frequency, longevity, rest, age, and gender both in Kcna1-/- mice and KD treated Kcna1-/-mice are involved in SUDEP. This provides valuable prediction for clinical application of KD for treatment of SUDEP.
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Affiliation(s)
- Yandong Ren
- School of Mental Health, Qiqihar Medical University, Qiqihar, China
| | - Jinlong Chang
- School of Mental Health, Qiqihar Medical University, Qiqihar, China
| | - Chengchong Li
- School of Mental Health, Qiqihar Medical University, Qiqihar, China
| | - Cuicui Jia
- School of Mental Health, Qiqihar Medical University, Qiqihar, China
| | - Ping Li
- School of Mental Health, Qiqihar Medical University, Qiqihar, China
| | - Yuhua Wang
- School of Mental Health, Qiqihar Medical University, Qiqihar, China
| | - Xiang-Ping Chu
- School of Mental Health, Qiqihar Medical University, Qiqihar, China.,Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, United States
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15
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Di Lorenzo C, Coppola G, Bracaglia M, Di Lenola D, Sirianni G, Rossi P, Di Lorenzo G, Parisi V, Serrao M, Cervenka MC, Pierelli F. A ketogenic diet normalizes interictal cortical but not subcortical responsivity in migraineurs. BMC Neurol 2019; 19:136. [PMID: 31228957 PMCID: PMC6588932 DOI: 10.1186/s12883-019-1351-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 05/31/2019] [Indexed: 11/26/2022] Open
Abstract
Background A short ketogenic diet (KD) treatment can prevent migraine attacks and correct excessive cortical response. Here, we aim to prove if the KD-related changes of cortical excitability are primarily due to cerebral cortex activity or are modulated by the brainstem. Methods Through the stimulation of the right supraorbital division of the trigeminal nerve, we concurrently interictally recorded the nociceptive blink reflex (nBR) and the pain-related evoked potentials (PREP) in 18 migraineurs patients without aura before and after 1-month on KD, while in metabolic ketosis. nBR and PREP reflect distinct brain structures activation: the brainstem and the cerebral cortex respectively. We estimated nBR R2 component area-under-the-curve as well as PREP amplitude habituation as the slope pof the linear regression between the 1st and the 2nd block of 5 averaged responses. Results Following 1-month on KD, the mean number of attacks and headache duration reduced significantly. Moreover, KD significantly normalized the interictal PREP habituation (pre: + 1.8, post: − 9.1, p = 0.012), while nBR deficit of habituation did not change. Conclusions The positive clinical effects we observed in a population of migraineurs by a 1-month KD treatment coexists with a normalization at the cortical level, not in the brainstem, of the typical interictal deficit of habituation. These findings suggest that the cerebral cortex may be the primary site of KD-related modulation. Trial registration ClinicalTrials.gov NCT03775252 (retrospectively registered, December 09, 2018).
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Affiliation(s)
| | - Gianluca Coppola
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University Rof Rome Polo Pontino, Latina, Italy
| | - Martina Bracaglia
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University Rof Rome Polo Pontino, Latina, Italy
| | - Davide Di Lenola
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University Rof Rome Polo Pontino, Latina, Italy
| | | | - Paolo Rossi
- INI, Headache Clinic, Grottaferrata (RM), Italy
| | - Giorgio Di Lorenzo
- Laboratory of Psychophysiology, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Vincenzo Parisi
- Research Unit of Neurophysiology of Vision and Neurophthalmology, IRCCS - Fondazione Bietti, Rome, Italy
| | - Mariano Serrao
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University Rof Rome Polo Pontino, Latina, Italy
| | - Mackenzie C Cervenka
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Francesco Pierelli
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University Rof Rome Polo Pontino, Latina, Italy.,IRCCS - Neuromed, Pozzilli, IS, Italy
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16
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Marchionni I, Oberoi M, Soltesz I, Alexander A. Ripple-related firing of identified deep CA1 pyramidal cells in chronic temporal lobe epilepsy in mice. Epilepsia Open 2019; 4:254-263. [PMID: 31168492 PMCID: PMC6546014 DOI: 10.1002/epi4.12310] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/02/2019] [Accepted: 01/19/2019] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE Temporal lobe epilepsy (TLE) is often associated with memory deficits. Reactivation of memory traces in the hippocampus occurs during sharp-wave ripples (SWRs; 140-250 Hz). To better understand the mechanisms underlying high-frequency oscillations and cognitive comorbidities in epilepsy, we evaluated how rigorously identified deep CA1 pyramidal cells (dPCs) discharge during SWRs in control and TLE mice. METHODS We used the unilateral intraamygdala kainate model of TLE in video-electroencephalography (EEG) verified chronically epileptic adult mice. Local field potential and single-cell recordings were performed using juxtacellular recordings from awake control and TLE mice resting on a spherical treadmill, followed by post hoc identification of the recorded cells. RESULTS Hippocampal SWRs in TLE mice occurred with increased intraripple frequency compared to control mice. The frequency of SWR events was decreased, whereas the overall frequency of SWRs, interictal epileptiform discharges, and high-frequency ripples (250-500 Hz) together was not altered. CA1 dPCs in TLE mice showed significantly increased firing during ripples as well as between the ripple events. The strength of ripple modulation of dPC discharges increased in TLE without alteration of the preferred phase of firing during the ripple waves. SIGNIFICANCE These juxtacellular electrophysiology data obtained from identified CA1 dPCs from chronically epileptic mice are in general agreement with recent findings indicating distortion of normal firing patterns during offline SWRs as a mechanism underlying deficits in memory consolidation in epilepsy. Because the primary seizure focus in our experiments was in the amygdala and we recorded from the CA1 region, these results are also in agreement with the presence of altered high-frequency oscillations in areas of secondary seizure spread.
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Affiliation(s)
- Ivan Marchionni
- Department of Anatomy & NeurobiologyUniversity of CaliforniaIrvineCalifornia
- Department of Biomedical Sciences and Padova Neuroscience CenterUniversity of PadovaPadovaItaly
| | - Michelle Oberoi
- Department of Anatomy & NeurobiologyUniversity of CaliforniaIrvineCalifornia
- University of CaliforniaRiverside School of MedicineRiversideCalifornia
| | - Ivan Soltesz
- Department of Anatomy & NeurobiologyUniversity of CaliforniaIrvineCalifornia
- Department of NeurosurgeryStanford UniversityStanfordCalifornia
| | - Allyson Alexander
- Department of NeurosurgeryAnschutz School of MedicineUniversity of Colorado DenverAuroraColorado
- Department of NeurosurgeryChildren's Hospital ColoradoAuroraColorado
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17
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Chen F, He X, Luan G, Li T. Role of DNA Methylation and Adenosine in Ketogenic Diet for Pharmacoresistant Epilepsy: Focus on Epileptogenesis and Associated Comorbidities. Front Neurol 2019; 10:119. [PMID: 30863356 PMCID: PMC6399128 DOI: 10.3389/fneur.2019.00119] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/29/2019] [Indexed: 01/02/2023] Open
Abstract
Epilepsy is a neurological disorder characterized by a long term propensity to produce unprovoked seizures and by the associated comorbidities including neurological, cognitive, psychiatric, and impairment the quality of life. Despite the clinic availability of several novel antiepileptic drugs (AEDs) with different mechanisms of action, more than one-third of patients with epilepsy suffer with pharmacoresistant epilepsy. Until now, no AEDs have been proven to confer the efficacy in alteration of disease progression or inhibition of the development of epilepsy. The ketogenic diet, the high-fat, low-carbohydrate composition is an alternative metabolic therapy for epilepsy, especially for children with drug-resistant epilepsy. Recently clinical and experimental results demonstrate its efficacy in ameliorating both seizures and comorbidities associated with epilepsy, such as cognitive/psychiatric concerns for the patients with refractory epilepsy. Of importance, ketogenic diet demonstrates to be a promising disease-modifying or partial antiepileptogenesis therapy for epilepsy. The mechanisms of action of ketogenic diet in epilepsy have been revealed recently, such as epigenetic mechanism for increase the adenosine level in the brain and inhibition of DNA methylation. In the present review, we will focus on the mechanisms of ketogenic diet therapies underlying adenosine system in the prevention of epileptogenesis and disease modification. In addition, we will review the role of ketogenic diet therapy in comorbidities associated epilepsy and the underlying mechanisms of adenosine.
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Affiliation(s)
- Fan Chen
- Beijing Key Laboratory of Epilepsy Research, Department of Neurology, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Xinghui He
- Beijing Key Laboratory of Epilepsy Research, Department of Neurosurgery, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Guoming Luan
- Beijing Key Laboratory of Epilepsy Research, Department of Neurosurgery, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Tianfu Li
- Beijing Key Laboratory of Epilepsy Research, Department of Neurology, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
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18
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Ling Y, Wang DD, Sun YX, Zhao DJ, Ni H. Neuro-Behavioral Status and the Hippocampal Expression of Metabolic Associated Genes in Wild-Type Rat Following a Ketogenic Diet. Front Neurol 2019; 10:65. [PMID: 30804881 PMCID: PMC6370680 DOI: 10.3389/fneur.2019.00065] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/17/2019] [Indexed: 01/16/2023] Open
Abstract
While a ketogenic diet (KD) is a well-established therapy for medically intractable epilepsy, clinical evidence of relevant adverse events of a KD has also been reported. We asked whether this kind of diet would have deleterious effects on wild-type brain function by evaluating KD-induced biochemical changes in the hippocampus as well as neurobehavioral changes occurring in wild-type rats. Fifty-four Sprague-Dawley rats were randomly assigned to three groups on postnatal day 28 (P28): wild-type rats fed with a KD qd (daily for 4 weeks, KD) or qod (every other day for 4 weeks, KOD), and wild-type rats fed with standard normal laboratory diet (ND). Neurobehavioral changes were observed on P35, P42, and P49. The hippocampal mossy fiber sprouting, the expression levels of zinc transporters (ZnTs) and lipid metabolism related genes were detected by Timm staining, RT-qPCR and western blot analysis, respectively, on P58. The KD-treated KOD and KD groups showed a significant delay of negative geotaxis reflex on P35, but not on P42 or P49. In the open field test, daily KD treatment only led to a reduction in exploratory activity and increased grooming times but induced no significant changes in the scores of vertical activity or delay time. KD qod treated rats (KOD) displayed a slight delay in the place navigation test on P35 compared with the KD group. There were no significant differences in Timm staining among the three groups. In parallel with these changes, KD treatment (both KD and KOD) induced significantly downregulated mRNA levels of Apoa1, Pdk4, and upregulated expression of ApoE, ANXN7, and cPLA2 in the hippocampus when compared with the ND group (except in the case of ApoE in the KOD group). Notably, both the mRNA and protein levels of cPLA2 in the KOD rats were significantly downregulated compared with the KD group but still markedly higher than in the ND group. No significant difference was found in ZnTs among the three groups. Our data suggest that early-life KD can provoke minor neurobehavioral effects in particular a delay in negative geotaxis reflex and an increase in grooming activity. The hippocampal lipid metabolism signaling pathway, especially cPLA2, may be the target of the protective effect of KD on long-term brain injury after developmental seizures.
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Affiliation(s)
- Ya Ling
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China.,The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Dan-Dan Wang
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Yu-Xiao Sun
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Dong-Jing Zhao
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Hong Ni
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
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19
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Zhu P, Li J, Zhang L, Liang Z, Tang B, Liao WP, Yi YH, Su T. Development-related aberrations in Kv1.1 α-subunit exert disruptive effects on bioelectrical activities of neurons in a mouse model of fragile X syndrome. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:140-151. [PMID: 29481897 DOI: 10.1016/j.pnpbp.2018.02.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 02/22/2018] [Accepted: 02/22/2018] [Indexed: 10/18/2022]
Abstract
Kv1.1, a Shaker homologue potassium channel, plays a critical role in homeostatic regulation of neuronal excitability. Aberrations in the functional properties of Kv1.1 have been implicated in several neurological disorders featured by neuronal hyperexcitability. Fragile X syndrome (FXS), the most common form of inherited mental retardation, is characterized by hyperexcitability in neural network and intrinsic membrane properties. The Kv1.1 channel provides an intriguing mechanistic candidate for FXS. We investigated the development-related expression pattern of the Kv1.1 α-subunit by using a Fmr1 knockout (KO) mouse model of FXS. Markedly decreased protein expression of Kv1.1 was found in neonatal and adult stages when compared to age-matched wild-type (WT) mice. Immunohistochemical investigations supported the delayed development-related increases in Kv1.1 expression, especially in CA3 pyramidal neurons. By applying a Kv1.1-specific blocker, dendrotoxin-κ (DTX-κ), we isolated the Kv1.1-mediated currents in the CA3 pyramidal neurons. The isolated DTX-κ-sensitive current of neurons from KO mice exhibited decreased amplitude, lower threshold of activation, and faster recovery from inactivation. The equivalent reduction in potassium current in the WT neurons following application of the appropriate amount of DTX-κ reproduced the enhanced firing abilities of KO neurons, suggesting the Kv1.1 channel as a critical contributor to the hyperexcitability of KO neurons. The role of Kv1.1 in controlling neuronal discharges was further supported by the parallel developmental trajectories of Kv1.1 expression, current amplitude, and discharge impacts, with a significant correlation between the amplitude of Kv1.1-mediated currents and Kv1.1-blocking-induced firing enhancement. These data suggest that the expression of the Kv1.1 α-subunit has a profound pathological relevance to hyperexcitability in FXS, as well as implications for normal development, maintenance, and control of neuronal activities.
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Affiliation(s)
- Pingping Zhu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China; Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, Guangzhou, China
| | - Jialing Li
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Liting Zhang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Zhanrong Liang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Bin Tang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Wei-Ping Liao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Yong-Hong Yi
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Tao Su
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China.
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Abstract
PURPOSE OF REVIEW High-fat, low-carbohydrate ketogenic diets have been used for almost a century for the treatment of epilepsy. Used traditionally for the treatment of refractory pediatric epilepsies, in recent years the use of ketogenic diets has experienced a revival to include the treatment of adulthood epilepsies as well as conditions ranging from autism to chronic pain and cancer. Despite the ability of ketogenic diet therapy to suppress seizures refractory to antiepileptic drugs and reports of lasting seizure freedom, the underlying mechanisms are poorly understood. This review explores new insights into mechanisms mobilized by ketogenic diet therapies. RECENT FINDINGS Ketogenic diets act through a combination of mechanisms, which are linked to the effects of ketones and glucose restriction, and to interactions with receptors, channels, and metabolic enzymes. Decanoic acid, a component of medium-chain triclycerides, contributes to seizure control through direct α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor inhibition, whereas drugs targeting lactate dehydrogenase reduce seizures through inhibition of a metabolic pathway. Ketogenic diet therapy also affects DNA methylation, a novel epigenetic mechanism of the diet. SUMMARY Ketogenic diet therapy combines several beneficial mechanisms that provide broad benefits for the treatment of epilepsy with the potential to not only suppress seizures but also to modify the course of the epilepsy.
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Simeone TA, Simeone KA, Stafstrom CE, Rho JM. Do ketone bodies mediate the anti-seizure effects of the ketogenic diet? Neuropharmacology 2018; 133:233-241. [PMID: 29325899 PMCID: PMC5858992 DOI: 10.1016/j.neuropharm.2018.01.011] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 11/27/2017] [Accepted: 01/07/2018] [Indexed: 01/01/2023]
Abstract
Although the mechanisms underlying the anti-seizure effects of the high-fat ketogenic diet (KD) remain unclear, a long-standing question has been whether ketone bodies (i.e., β-hydroxybutyrate, acetoacetate and acetone), either alone or in combination, contribute mechanistically. The traditional belief has been that while ketone bodies reflect enhanced fatty acid oxidation and a general shift toward intermediary metabolism, they are not likely to be the key mediators of the KD's clinical effects, as blood levels of β-hydroxybutyrate do not correlate consistently with improved seizure control. Against this unresolved backdrop, new data support ketone bodies as having anti-seizure actions. Specifically, β-hydroxybutyrate has been shown to interact with multiple novel molecular targets such as histone deacetylases, hydroxycarboxylic acid receptors on immune cells, and the NLRP3 inflammasome. Clearly, as a diet-based therapy is expected to render a broad array of biochemical, molecular, and cellular changes, no single mechanism can explain how the KD works. Specific metabolic substrates or enzymes are only a few of many important factors influenced by the KD that can collectively influence brain hyperexcitability and hypersynchrony. This review summarizes recent novel experimental findings supporting the anti-seizure and neuroprotective properties of ketone bodies.
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Affiliation(s)
- Timothy A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Kristina A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Carl E Stafstrom
- Department of Neurology, and Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jong M Rho
- Department of Pediatrics, Department of Clinical Neurosciences, and Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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22
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Hernandez AR, Hernandez CM, Campos KT, Truckenbrod LM, Sakarya Y, McQuail JA, Carter CS, Bizon JL, Maurer AP, Burke SN. The Antiepileptic Ketogenic Diet Alters Hippocampal Transporter Levels and Reduces Adiposity in Aged Rats. J Gerontol A Biol Sci Med Sci 2018; 73:450-458. [PMID: 29040389 PMCID: PMC5861916 DOI: 10.1093/gerona/glx193] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 10/07/2017] [Indexed: 01/21/2023] Open
Abstract
Nutritional ketosis is induced by high fat/low carbohydrate dietary regimens, which produce high levels of circulating ketone bodies, shifting metabolism away from glucose utilization. While ketogenic diets (KD) were initially introduced to suppress seizures, they are garnering attention for their potential to treat a myriad of neurodegenerative and metabolic disorders that are associated with advanced age. The feasibility and physiological impact of implementing a long-term KD in old animals, however, has not been systematically examined. In this study, young and aged rats consumed a calorically- and nutritionally-matched KD or control diet for 12 weeks. All KD-fed rats maintained higher levels of BHB and lower levels of glucose relative to controls. However, it took the aged rats longer to reach asymptotic levels of BHB compared to young animals. Moreover, KD-fed rats had significantly less visceral white and brown adipose tissue than controls without a loss of lean mass. Interestingly, the KD led to significant alterations in protein levels of hippocampal transporters for monocarboxylates, glucose, and vesicular glutamate and gamma-aminobutyric acid. Most notably, the age-related decline in vesicular glutamate transporter expression was reversed by the KD. These data demonstrate the feasibility and potential benefits of KDs for treating age-associated neural dysfunction.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Andrew P Maurer
- Department of Neuroscience, McKnight Brain Institute
- Department of Biomedical Engineering, University of Florida, Gainesville
| | - Sara N Burke
- Department of Neuroscience, McKnight Brain Institute
- Institute on Aging, University of Florida, Gainesville
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23
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Martínez-François JR, Fernández-Agüera MC, Nathwani N, Lahmann C, Burnham VL, Danial NN, Yellen G. BAD and K ATP channels regulate neuron excitability and epileptiform activity. eLife 2018; 7:32721. [PMID: 29368690 PMCID: PMC5785210 DOI: 10.7554/elife.32721] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/12/2018] [Indexed: 12/17/2022] Open
Abstract
Brain metabolism can profoundly influence neuronal excitability. Mice with genetic deletion or alteration of Bad (BCL-2 agonist of cell death) exhibit altered brain-cell fuel metabolism, accompanied by resistance to acutely induced epileptic seizures; this seizure protection is mediated by ATP-sensitive potassium (KATP) channels. Here we investigated the effect of BAD manipulation on KATP channel activity and excitability in acute brain slices. We found that BAD’s influence on neuronal KATP channels was cell-autonomous and directly affected dentate granule neuron (DGN) excitability. To investigate the role of neuronal KATP channels in the anticonvulsant effects of BAD, we imaged calcium during picrotoxin-induced epileptiform activity in entorhinal-hippocampal slices. BAD knockout reduced epileptiform activity, and this effect was lost upon knockout or pharmacological inhibition of KATP channels. Targeted BAD knockout in DGNs alone was sufficient for the antiseizure effect in slices, consistent with a ‘dentate gate’ function that is reinforced by increased KATP channel activity.
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Affiliation(s)
| | | | - Nidhi Nathwani
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Carolina Lahmann
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Veronica L Burnham
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Nika N Danial
- Department of Neurobiology, Harvard Medical School, Boston, United States.,Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, United States
| | - Gary Yellen
- Department of Neurobiology, Harvard Medical School, Boston, United States
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24
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Iyer SH, Matthews SA, Simeone TA, Maganti R, Simeone KA. Accumulation of rest deficiency precedes sudden death of epileptic Kv1.1 knockout mice, a model of sudden unexpected death in epilepsy. Epilepsia 2017; 59:92-105. [PMID: 29193044 DOI: 10.1111/epi.13953] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2017] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Chronic sleep deficiency is associated with early mortality. In the epileptic population, there is a higher prevalence of sleep disorders, and individuals with severe refractory epilepsy are at greater risk of premature mortality than the general population. Sudden unexpected death in epilepsy affects 1:1000 cases of epilepsy each year. Ketogenic diet (KD) treatment is one of the few effective options for refractory seizures. Despite KD reducing seizures and increasing longevity in Kv1.1 knockout (KO) mice, they still succumb to sudden death. This study aims to determine whether (1) the rest profiles of KO and KD-treated KO (KOKD) mice resemble each other as a function of either age or proximity to death and (2) the timing of death correlates with acute or chronic changes in rest. METHODS Noninvasive actimetry was used to monitor rest throughout the lives of KO and wild-type (WT) littermates administered standard diet or KD. RESULTS As KO mice age, rest is reduced (P < .0001). Rest is significantly improved in KDKO mice (P < .0001), resembling WT values at several ages. When age is removed as a variable and data are realigned to the day of death, the rest profiles of KO and KOKD groups worsen to similar degrees as a function of proximity to death. The amount of rest acutely is not sensitive to the timing of death, whereas chronic rest deficiency profiles (10-15 days prior to death) of both groups were indistinguishable. Chronic accumulation of rest deficiency over the final 15 days was associated with 75% of deaths. SIGNIFICANCE Our data suggest that the accumulated rest deficiency is associated with sudden death in Kv1.1 KO mice. These data (1) support the proposed clinical hypothesis that chronic sleep deficiency may be associated with early mortality in epileptic patients and (2) warrant future preclinical and clinical studies on sleep monitoring in epileptic patients.
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Affiliation(s)
- Shruthi H Iyer
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Stephanie A Matthews
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Timothy A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
| | - Rama Maganti
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Kristina A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, USA
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25
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Dallérac G, Moulard J, Benoist JF, Rouach S, Auvin S, Guilbot A, Lenoir L, Rouach N. Non-ketogenic combination of nutritional strategies provides robust protection against seizures. Sci Rep 2017; 7:5496. [PMID: 28710408 PMCID: PMC5511156 DOI: 10.1038/s41598-017-05542-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 05/31/2017] [Indexed: 12/27/2022] Open
Abstract
Epilepsy is a neurological condition that affects 1% of the world population. Conventional treatments of epilepsy use drugs targeting neuronal excitability, inhibitory or excitatory transmission. Yet, one third of patients presents an intractable form of epilepsy and fails to respond to pharmacological anti-epileptic strategies. The ketogenic diet is a well-established non-pharmacological treatment that has been proven to be effective in reducing seizure frequency in the pharmaco-resistant patients. This dietary solution is however extremely restrictive and can be associated with complications caused by the high [fat]:[carbohydrate + protein] ratio. Recent advances suggest that the traditional 4:1 ratio of the ketogenic diet is not a requisite for its therapeutic effect. We show here that combining nutritional strategies targeting specific amino-acids, carbohydrates and fatty acids with a low [fat]:[proteins + carbohydrates] ratio also reduces excitatory drive and protects against seizures to the same extent as the ketogenic diet. Similarly, the morphological and molecular correlates of temporal lobe seizures were reduced in animals fed with the combined diet. These results provide evidence that low-fat dietary strategies more palatable than the ketogenic diet could be useful in epilepsy.
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Affiliation(s)
- Glenn Dallérac
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, 75005, France.
| | - Julien Moulard
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, 75005, France
| | | | - Stefan Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, 75005, France
| | - Stéphane Auvin
- AP-HP, Hôpital Robert Debré, Service de Neurologie Pédiatrique, Paris, France
| | - Angèle Guilbot
- PILEJE Laboratoire, 37 quai de Grenelle, 75015, Paris, France
| | - Loïc Lenoir
- PILEJE Laboratoire, 37 quai de Grenelle, 75015, Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, 75005, France.
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Alteration of Neuronal Excitability and Short-Term Synaptic Plasticity in the Prefrontal Cortex of a Mouse Model of Mental Illness. J Neurosci 2017; 37:4158-4180. [PMID: 28283561 DOI: 10.1523/jneurosci.4345-15.2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/17/2017] [Accepted: 02/22/2017] [Indexed: 01/28/2023] Open
Abstract
Using a genetic mouse model that faithfully recapitulates a DISC1 genetic alteration strongly associated with schizophrenia and other psychiatric disorders, we examined the impact of this mutation within the prefrontal cortex. Although cortical layering, cytoarchitecture, and proteome were found to be largely unaffected, electrophysiological examination of the mPFC revealed both neuronal hyperexcitability and alterations in short-term synaptic plasticity consistent with enhanced neurotransmitter release. Increased excitability of layer II/III pyramidal neurons was accompanied by consistent reductions in voltage-activated potassium currents near the action potential threshold as well as by enhanced recruitment of inputs arising from superficial layers to layer V. We further observed reductions in both the paired-pulse ratios and the enhanced short-term depression of layer V synapses arising from superficial layers consistent with enhanced neurotransmitter release at these synapses. Recordings from layer II/III pyramidal neurons revealed action potential widening that could account for enhanced neurotransmitter release. Significantly, we found that reduced functional expression of the voltage-dependent potassium channel subunit Kv1.1 substantially contributes to both the excitability and short-term plasticity alterations that we observed. The underlying dysregulation of Kv1.1 expression was attributable to cAMP elevations in the PFC secondary to reduced phosphodiesterase 4 activity present in Disc1 deficiency and was rescued by pharmacological blockade of adenylate cyclase. Our results demonstrate a potentially devastating impact of Disc1 deficiency on neural circuit function, partly due to Kv1.1 dysregulation that leads to a dual dysfunction consisting of enhanced neuronal excitability and altered short-term synaptic plasticity.SIGNIFICANCE STATEMENT Schizophrenia is a profoundly disabling psychiatric illness with a devastating impact not only upon the afflicted but also upon their families and the broader society. Although the underlying causes of schizophrenia remain poorly understood, a growing body of studies has identified and strongly implicated various specific risk genes in schizophrenia pathogenesis. Here, using a genetic mouse model, we explored the impact of one of the most highly penetrant schizophrenia risk genes, DISC1, upon the medial prefrontal cortex, the region believed to be most prominently dysfunctional in schizophrenia. We found substantial derangements in both neuronal excitability and short-term synaptic plasticity-parameters that critically govern neural circuit information processing-suggesting that similar changes may critically, and more broadly, underlie the neural computational dysfunction prototypical of schizophrenia.
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Kawamura MJ, Ruskin DN, Masino SA. Metabolic Therapy for Temporal Lobe Epilepsy in a Dish: Investigating Mechanisms of Ketogenic Diet using Electrophysiological Recordings in Hippocampal Slices. Front Mol Neurosci 2016; 9:112. [PMID: 27847463 PMCID: PMC5088211 DOI: 10.3389/fnmol.2016.00112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 10/17/2016] [Indexed: 11/13/2022] Open
Abstract
The hippocampus is prone to epileptic seizures and is a key brain region and experimental platform for investigating mechanisms associated with the abnormal neuronal excitability that characterizes a seizure. Accordingly, the hippocampal slice is a common in vitro model to study treatments that may prevent or reduce seizure activity. The ketogenic diet is a metabolic therapy used to treat epilepsy in adults and children for nearly 100 years; it can reduce or eliminate even severe or refractory seizures. New insights into its underlying mechanisms have been revealed by diverse types of electrophysiological recordings in hippocampal slices. Here we review these reports and their relevant mechanistic findings. We acknowledge that a major difficulty in using hippocampal slices is the inability to reproduce precisely the in vivo condition of ketogenic diet feeding in any in vitro preparation, and progress has been made in this in vivo/in vitro transition. Thus far at least three different approaches are reported to reproduce relevant diet effects in the hippocampal slices: (1) direct application of ketone bodies; (2) mimicking the ketogenic diet condition during a whole-cell patch-clamp technique; and (3) reduced glucose incubation of hippocampal slices from ketogenic diet–fed animals. Significant results have been found with each of these methods and provide options for further study into short- and long-term mechanisms including Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels, vesicular glutamate transporter (VGLUT), pannexin channels and adenosine receptors underlying ketogenic diet and other forms of metabolic therapy.
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Affiliation(s)
| | - David N Ruskin
- Department of Psychology and Neuroscience Program, Trinity College Hartford, CT, USA
| | - Susan A Masino
- Department of Psychology and Neuroscience Program, Trinity College Hartford, CT, USA
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28
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Simeone TA, Matthews SA, Samson KK, Simeone KA. Regulation of brain PPARgamma2 contributes to ketogenic diet anti-seizure efficacy. Exp Neurol 2016; 287:54-64. [PMID: 27527983 DOI: 10.1016/j.expneurol.2016.08.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 08/05/2016] [Accepted: 08/11/2016] [Indexed: 12/23/2022]
Abstract
The ketogenic diet (KD) is an effective therapy primarily used in pediatric patients whom are refractory to current anti-seizure medications. The mechanism of the KD is not completely understood, but is thought to involve anti-inflammatory and anti-oxidant processes. The nutritionally-regulated transcription factor peroxisome proliferator activated receptor gamma, PPARγ, regulates genes involved in anti-inflammatory and anti-oxidant pathways. Moreover, endogenous ligands of PPARγ include fatty acids suggesting a potential role in the effects of the KD. Here, we tested the hypothesis that PPARγ contributes to the anti-seizure efficacy of the KD. We found that the KD increased nuclear protein content of the PPARγ2 splice variant by 2-4 fold (P<0.05) in brain homogenates from wild-type (WT) and epileptic Kv1.1 knockout (KO) mice, while not affecting PPARγ1. The KD reduced the frequency of seizures in Kv1.1KO mice by ~70% (P<0.01). GW9662, a PPARγ antagonist, prevented KD-mediated changes in PPARγ2 expression and prevented the anti-seizure efficacy of the KD in Kv1.1KO mice. Further supporting the association of PPARγ2 in mediating KD actions, the KD significantly prolonged the latency to flurothyl-induced seizure in WT mice by ~20-35% (P<0.01), but was ineffective in PPARγ2KO mice and neuron-specific PPARγKO mice. Finally, administering the PPARγ agonist pioglitazone increased PPARγ2 expression by 2-fold (P<0.01) and reduced seizures in Kv1.1KO mice by ~80% (P<0.01). Our findings implicate brain PPARγ2 among the mechanisms by which the KD reduces seizures and strongly support the development of PPARγ2 as a therapeutic target for severe, refractory epilepsy.
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Affiliation(s)
- Timothy A Simeone
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE 68174, USA.
| | - Stephanie A Matthews
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE 68174, USA
| | - Kaeli K Samson
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE 68174, USA
| | - Kristina A Simeone
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE 68174, USA
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Simeone KA, Matthews SA, Rho JM, Simeone TA. Ketogenic diet treatment increases longevity in Kcna1-null mice, a model of sudden unexpected death in epilepsy. Epilepsia 2016; 57:e178-82. [PMID: 27346881 DOI: 10.1111/epi.13444] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2016] [Indexed: 12/28/2022]
Abstract
Individuals with poorly controlled epilepsy have a higher risk for sudden unexpected death in epilepsy (SUDEP). With approximately one third of people with epilepsy not achieving adequate seizure control with current antiseizure drugs, there is a critical need to identify treatments that reduce risk factors for SUDEP. The Kcna1-null mutant mouse models risk factors and terminal events associated with SUDEP. In the current study, we demonstrate the progressive nature of epilepsy and sudden death in this model (mean age of mortality (± SEM), postnatal day [P] 42.8 ± 1.3) and tested the hypothesis that long-term treatment with the ketogenic diet (KD) will prolong the life of Kcna1-null mice. We found that the KD postpones disease progression by delaying the onset of severe seizures and increases the lifespan of these mutant mice by 47%. Future studies are needed to determine the mechanisms underlying the KD effects on longevity.
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Affiliation(s)
- Kristina A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska, U.S.A
| | - Stephanie A Matthews
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska, U.S.A
| | - Jong M Rho
- Departments of Pediatrics, Clinical Neurosciences, Physiology & Pharmacology, Alberta Children's Hospital Research Institute for Child and Maternal Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Timothy A Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska, U.S.A
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30
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Di Lorenzo C, Coppola G, Bracaglia M, Di Lenola D, Evangelista M, Sirianni G, Rossi P, Di Lorenzo G, Serrao M, Parisi V, Pierelli F. Cortical functional correlates of responsiveness to short-lasting preventive intervention with ketogenic diet in migraine: a multimodal evoked potentials study. J Headache Pain 2016; 17:58. [PMID: 27245682 PMCID: PMC4887398 DOI: 10.1186/s10194-016-0650-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/27/2016] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Here, we aim to identify cortical electrofunctional correlates of responsiveness to short-lasting preventiveintervention with ketogenic diet (KD) in migraine. METHODS Eighteen interictal migraineurs underwent visual (VEPs) and median nerve somatosensory (SSEPs) evokedpotentials before and after 1 month of KD during ketogenesis. We measured VEPs N1-P1 and SSEPs N20-P25 amplitudes respectively in six and in two sequential blocks of 100 sweeps as well as habituation as theslope of the linear regression between block 1 to 6 for VEPs or between 1 to 2 for SSEPs. RESULTS After 1-month of KD, a significant reduction in the mean attack frequency and duration was observed (all P< 0.001). The KD did not change the 1st SSEP and VEP block of responses, but significantly inducednormalization of the interictally reduced VEPs and SSEPs (all p < 0.01) habituation during the subsequentblocks. CONCLUSIONS KD could restore normal EPs habituation curves during stimulus repetition without significantly changing theearly amplitude responses. Thus, we hypothesize that KD acts on habituation regulating the balancebetween excitation and inhibition at the cortical level.
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Affiliation(s)
| | - Gianluca Coppola
- Department of Neurophysiology of Vision and Neurophthalmology, G. B. Bietti Foundation-IRCCS, Rome, Italy
| | - Martina Bracaglia
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University of Rome Polo Pontino, Latina, Italy
| | - Davide Di Lenola
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University of Rome Polo Pontino, Latina, Italy
| | - Maurizio Evangelista
- Istituto di Anestesiologia, Rianimazione e Terapia del Dolore, Università Cattolica del Sacro Cuore/CIC, Rome, Italy
| | - Giulio Sirianni
- Delle Medical Center, Wellness and Dietary Medicine, Rome, Italy
| | - Paolo Rossi
- INI, Headache Clinic, Grottaferrata, (RM), Italy
| | - Giorgio Di Lorenzo
- Department of Systems Medicine, University of Rome "Tor Vergata", Laboratory of Psychophysiology, Rome, Italy
| | - Mariano Serrao
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University of Rome Polo Pontino, Latina, Italy
| | - Vincenzo Parisi
- Department of Neurophysiology of Vision and Neurophthalmology, G. B. Bietti Foundation-IRCCS, Rome, Italy
| | - Francesco Pierelli
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University of Rome Polo Pontino, Latina, Italy.,INM Neuromed IRCCS, Pozzilli, (IS), Italy
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31
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Roundtree HM, Simeone TA, Johnson C, Matthews SA, Samson KK, Simeone KA. Orexin Receptor Antagonism Improves Sleep and Reduces Seizures in Kcna1-null Mice. Sleep 2016. [PMID: 26446112 DOI: 10.5665/sleep.5444.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVE Comorbid sleep disorders occur in approximately one-third of people with epilepsy. Seizures and sleep disorders have an interdependent relationship where the occurrence of one can exacerbate the other. Orexin, a wake-promoting neuropeptide, is associated with sleep disorder symptoms. Here, we tested the hypothesis that orexin dysregulation plays a role in the comorbid sleep disorder symptoms in the Kcna1-null mouse model of temporal lobe epilepsy. METHODS Rest-activity was assessed using infrared beam actigraphy. Sleep architecture and seizures were assessed using continuous video-electroencephalography-electromyography recordings in Kcna1-null mice treated with vehicle or the dual orexin receptor antagonist, almorexant (100 mg/kg, intraperitoneally). Orexin levels in the lateral hypothalamus/perifornical region (LH/P) and hypothalamic pathology were assessed with immunohistochemistry and oxygen polarography. RESULTS Kcna1-null mice have increased latency to rapid eye movement (REM) sleep onset, sleep fragmentation, and number of wake epochs. The numbers of REM and non-REM (NREM) sleep epochs are significantly reduced in Kcna1-null mice. Severe seizures propagate to the wake-promoting LH/P where injury is apparent (indicated by astrogliosis, blood-brain barrier permeability, and impaired mitochondrial function). The number of orexin-positive neurons is increased in the LH/P compared to wild-type LH/P. Treatment with a dual orexin receptor antagonist significantly increases the number and duration of NREM sleep epochs and reduces the latency to REM sleep onset. Further, almorexant treatment reduces the incidence of severe seizures and overall seizure burden. Interestingly, we report a significant positive correlation between latency to REM onset and seizure burden in Kcna1-null mice. CONCLUSION Dual orexin receptor antagonists may be an effective sleeping aid in epilepsy, and warrants further study on their somnogenic and ant-seizure effects in other epilepsy models.
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Affiliation(s)
| | - Timothy A Simeone
- Pharmacology Department, Creighton University School of Medicine, Omaha, NE
| | - Chaz Johnson
- Pharmacology Department, Creighton University School of Medicine, Omaha, NE
| | | | - Kaeli K Samson
- Pharmacology Department, Creighton University School of Medicine, Omaha, NE
| | - Kristina A Simeone
- Pharmacology Department, Creighton University School of Medicine, Omaha, NE
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Roundtree HM, Simeone TA, Johnson C, Matthews SA, Samson KK, Simeone KA. Orexin Receptor Antagonism Improves Sleep and Reduces Seizures in Kcna1-null Mice. Sleep 2016; 39:357-68. [PMID: 26446112 DOI: 10.5665/sleep.5444] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 08/28/2015] [Indexed: 01/14/2023] Open
Abstract
STUDY OBJECTIVE Comorbid sleep disorders occur in approximately one-third of people with epilepsy. Seizures and sleep disorders have an interdependent relationship where the occurrence of one can exacerbate the other. Orexin, a wake-promoting neuropeptide, is associated with sleep disorder symptoms. Here, we tested the hypothesis that orexin dysregulation plays a role in the comorbid sleep disorder symptoms in the Kcna1-null mouse model of temporal lobe epilepsy. METHODS Rest-activity was assessed using infrared beam actigraphy. Sleep architecture and seizures were assessed using continuous video-electroencephalography-electromyography recordings in Kcna1-null mice treated with vehicle or the dual orexin receptor antagonist, almorexant (100 mg/kg, intraperitoneally). Orexin levels in the lateral hypothalamus/perifornical region (LH/P) and hypothalamic pathology were assessed with immunohistochemistry and oxygen polarography. RESULTS Kcna1-null mice have increased latency to rapid eye movement (REM) sleep onset, sleep fragmentation, and number of wake epochs. The numbers of REM and non-REM (NREM) sleep epochs are significantly reduced in Kcna1-null mice. Severe seizures propagate to the wake-promoting LH/P where injury is apparent (indicated by astrogliosis, blood-brain barrier permeability, and impaired mitochondrial function). The number of orexin-positive neurons is increased in the LH/P compared to wild-type LH/P. Treatment with a dual orexin receptor antagonist significantly increases the number and duration of NREM sleep epochs and reduces the latency to REM sleep onset. Further, almorexant treatment reduces the incidence of severe seizures and overall seizure burden. Interestingly, we report a significant positive correlation between latency to REM onset and seizure burden in Kcna1-null mice. CONCLUSION Dual orexin receptor antagonists may be an effective sleeping aid in epilepsy, and warrants further study on their somnogenic and ant-seizure effects in other epilepsy models.
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Affiliation(s)
| | - Timothy A Simeone
- Pharmacology Department, Creighton University School of Medicine, Omaha, NE
| | - Chaz Johnson
- Pharmacology Department, Creighton University School of Medicine, Omaha, NE
| | | | - Kaeli K Samson
- Pharmacology Department, Creighton University School of Medicine, Omaha, NE
| | - Kristina A Simeone
- Pharmacology Department, Creighton University School of Medicine, Omaha, NE
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Blaise JH, Ruskin DN, Koranda JL, Masino SA. Effects of a ketogenic diet on hippocampal plasticity in freely moving juvenile rats. Physiol Rep 2015; 3:3/5/e12411. [PMID: 26009636 PMCID: PMC4463838 DOI: 10.14814/phy2.12411] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ketogenic diets are low-carbohydrate, sufficient protein, high-fat diets with anticonvulsant activity used primarily as a treatment for pediatric epilepsy. The anticonvulsant mechanism is thought to involve elevating inhibition and/or otherwise limiting excitability in the brain. Such a mechanism, however, might also significantly affect normal brain activity and limit synaptic plasticity, effects that would be important to consider in the developing brain. To assess ketogenic diet effects on synaptic transmission and plasticity, electrophysiological recordings were performed at the perforant path/dentate gyrus synapse in awake, freely-behaving juvenile male rats. Electrodes were implanted 1 week prior to recording. Animals were fed regular chow or a ketogenic diet ad libitum for 3 weeks before recording. Although the ketogenic diet did not significantly alter baseline excitability (assessed by input–output curves) or short-term plasticity (using the paired-pulse ratio), it did reduce the magnitude of long-term potentiation at all poststimulation timepoints out to the last time measured (48 h). The results suggest an effect of ketogenic diet-feeding on the induction magnitude but not the maintenance of long-term potentiation. The lack of effect of the diet on baseline transmission and the paired-pulse ratio suggests a mechanism that limits excitation preferentially in conditions of strong stimulation, consonant with clinical reports in which the ketogenic diet alleviates seizures without a major impact on normal brain activity. Limiting plasticity in a seizure-susceptible network may limit seizure-induced epileptogenesis which may subserve the ongoing benefit of the ketogenic diet in epilepsy.
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Affiliation(s)
- J Harry Blaise
- Department of Engineering, Trinity College, Hartford, Connecticut Neuroscience Program, Trinity College, Hartford, Connecticut
| | - David N Ruskin
- Neuroscience Program, Trinity College, Hartford, Connecticut Department of Psychology, Trinity College, Hartford, Connecticut
| | | | - Susan A Masino
- Neuroscience Program, Trinity College, Hartford, Connecticut Department of Psychology, Trinity College, Hartford, Connecticut
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