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Soni ND, Swain A, Jacobs P, Juul H, Armbruster R, Nanga RPR, Nath K, Wiers C, Detre J, Reddy R. In vivo assessment of β-hydroxybutyrate metabolism in mouse brain using deuterium ( 2 H) MRS. Magn Reson Med 2023; 90:259-269. [PMID: 36971349 PMCID: PMC10662955 DOI: 10.1002/mrm.29648] [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: 11/04/2022] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 05/01/2023]
Abstract
PURPOSE To monitor the metabolic turnover of β-hydroxybutyrate (BHB) oxidation using 2 H-MRS in conjunction with intravenous administration of 2 H labeled BHB. METHODS Nine-month-old mice were infused with [3,4,4,4]-2 H4 -BHB (d4 -BHB; 3.11 g/kg) through the tail vein using a bolus variable infusion rate for a period of 90 min. The labeling of downstream cerebral metabolites from the oxidative metabolism of d4 -BHB was monitored using 2 H-MRS spectra acquired with a home-built 2 H surface coil on a 9.4T preclinical MR scanner with a temporal resolution of 6.25 min. An exponential model was fit to the BHB and glutamate/glutamine (Glx) turnover curves to determine rate constants of metabolite turnover and to aid in the visualization of metabolite time courses. RESULTS Deuterium label was incorporated into Glx from BHB metabolism through the tricarboxylic acid (TCA) cycle, with an increase in the level of [4,4]-2 H2 -Glx (d2 -Glx) over time and reaching a quasi-steady state concentration of ∼0.6 ± 0.1 mM following 30 min of infusion. Complete oxidative metabolic breakdown of d4 -BHB also resulted in the formation of semi-heavy water (HDO), with a four-fold (10.1 to ∼42.1 ± 7.3 mM) linear (R2 = 0.998) increase in its concentration by the end of infusion. The rate constant of Glx turnover from d4 -BHB metabolism was determined to be 0.034 ± 0.004 min-1 . CONCLUSION 2 H-MRS can be used to monitor the cerebral metabolism of BHB with its deuterated form by measuring the downstream labeling of Glx. The integration of 2 H-MRS with deuterated BHB substrate provides an alternative and clinically promising MRS tool to detect neurometabolic fluxes in healthy and disease conditions.
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Affiliation(s)
- Narayan Datt Soni
- Department of Radiology, Center for Advanced Metabolic Imaging in Precision Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Anshuman Swain
- Department of Radiology, Center for Advanced Metabolic Imaging in Precision Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA
| | - Paul Jacobs
- Department of Radiology, Center for Advanced Metabolic Imaging in Precision Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA
| | - Halvor Juul
- Department of Radiology, Center for Advanced Metabolic Imaging in Precision Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ryan Armbruster
- Department of Radiology, Center for Advanced Metabolic Imaging in Precision Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi Prakash Reddy Nanga
- Department of Radiology, Center for Advanced Metabolic Imaging in Precision Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kavindra Nath
- Department of Radiology, Center for Advanced Metabolic Imaging in Precision Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Corinde Wiers
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - John Detre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ravinder Reddy
- Department of Radiology, Center for Advanced Metabolic Imaging in Precision Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Yakupova EI, Bocharnikov AD, Plotnikov EY. Effects of Ketogenic Diet on Muscle Metabolism in Health and Disease. Nutrients 2022; 14:nu14183842. [PMID: 36145218 PMCID: PMC9505561 DOI: 10.3390/nu14183842] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/09/2022] [Accepted: 09/11/2022] [Indexed: 11/16/2022] Open
Abstract
Dietary intervention is widely used as a therapeutic approach ranging from the treatment of neurological disorders to attempts to extend lifespan. The most important effect of various diets is a change in energy metabolism. Since muscles constitute 40% of total body mass and are one of the major sites of glucose and energy uptake, various diets primarily affect their metabolism, causing both positive and negative changes in physiology and signaling pathways. In this review, we discuss changes in the energy metabolism of muscles under conditions of the low-carbohydrate, high-fat diet/ketogenic diet (KD), fasting, or administration of exogenous ketone bodies, which are all promising approaches to the treatment of various diseases. KD's main influence on the muscle is expressed through energy metabolism changes, particularly decreased carbohydrate and increased fat oxidation. This affects mitochondrial quantity, oxidative metabolism, antioxidant capacity, and activity of enzymes. The benefits of KD for muscles stay controversial, which could be explained by its different effects on various fiber types, including on muscle fiber-type ratio. The impacts of KD or of its mimetics are largely beneficial but could sometimes induce adverse effects such as cardiac fibrosis.
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Affiliation(s)
- Elmira I. Yakupova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Correspondence: (E.I.Y.); (E.Y.P.)
| | - Alexey D. Bocharnikov
- International School of Medicine of the Future, Sechenov First Moscow State Medical University, 119992 Moscow, Russia
| | - Egor Y. Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology, 117997 Moscow, Russia
- Correspondence: (E.I.Y.); (E.Y.P.)
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3
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Poff AM, Moss S, Soliven M, D'Agostino DP. Ketone Supplementation: Meeting the Needs of the Brain in an Energy Crisis. Front Nutr 2022; 8:783659. [PMID: 35004814 PMCID: PMC8734638 DOI: 10.3389/fnut.2021.783659] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 12/03/2021] [Indexed: 12/11/2022] Open
Abstract
Diverse neurological disorders are associated with a deficit in brain energy metabolism, often characterized by acute or chronic glucose hypometabolism. Ketones serve as the brain's only significant alternative fuel and can even become the primary fuel in conditions of limited glucose availability. Thus, dietary supplementation with exogenous ketones represents a promising novel therapeutic strategy to help meet the energetic needs of the brain in an energy crisis. Preliminary evidence suggests ketosis induced by exogenous ketones may attenuate damage or improve cognitive and motor performance in neurological conditions such as seizure disorders, mild cognitive impairment, Alzheimer's disease, and neurotrauma.
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Affiliation(s)
- Angela M Poff
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Sara Moss
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Maricel Soliven
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Dominic P D'Agostino
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
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5
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Ketogenic Diet as a potential treatment for traumatic brain injury in mice. Sci Rep 2021; 11:23559. [PMID: 34876621 PMCID: PMC8651717 DOI: 10.1038/s41598-021-02849-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/18/2021] [Indexed: 11/21/2022] Open
Abstract
Traumatic brain injury (TBI) is a brain dysfunction without present treatment. Previous studies have shown that animals fed ketogenic diet (KD) perform better in learning tasks than those fed standard diet (SD) following brain injury. The goal of this study was to examine whether KD is a neuroprotective in TBI mouse model. We utilized a closed head injury model to induce TBI in mice, followed by up to 30 days of KD/SD. Elevated levels of ketone bodies were confirmed in the blood following KD. Cognitive and behavioral performance was assessed post injury and molecular and cellular changes were assessed within the temporal cortex and hippocampus. Y-maze and Novel Object Recognition tasks indicated that mTBI mice maintained on KD displayed better cognitive abilities than mTBI mice maintained on SD. Mice maintained on SD post-injury demonstrated SIRT1 reduction when compared with uninjured and KD groups. In addition, KD management attenuated mTBI-induced astrocyte reactivity in the dentate gyrus and decreased degeneration of neurons in the dentate gyrus and in the cortex. These results support accumulating evidence that KD may be an effective approach to increase the brain’s resistance to damage and suggest a potential new therapeutic strategy for treating TBI.
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Ketogenic diet reduces early mortality following traumatic brain injury in Drosophila via the PPARγ ortholog Eip75B. PLoS One 2021; 16:e0258873. [PMID: 34699541 PMCID: PMC8547619 DOI: 10.1371/journal.pone.0258873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/06/2021] [Indexed: 11/19/2022] Open
Abstract
Traumatic brain injury (TBI) is a common neurological disorder whose outcomes vary widely depending on a variety of environmental factors, including diet. Using a Drosophila melanogaster TBI model that reproduces key aspects of TBI in humans, we previously found that the diet consumed immediately following a primary brain injury has a substantial effect on the incidence of mortality within 24 h (early mortality). Flies that receive equivalent primary injuries have a higher incidence of early mortality when fed high-carbohydrate diets versus water. Here, we report that flies fed high-fat ketogenic diet (KD) following TBI exhibited early mortality that was equivalent to that of flies fed water and that flies protected from early mortality by KD continued to show survival benefits weeks later. KD also has beneficial effects in mammalian TBI models, indicating that the mechanism of action of KD is evolutionarily conserved. To probe the mechanism, we examined the effect of KD in flies mutant for Eip75B, an ortholog of the transcription factor PPARγ (peroxisome proliferator-activated receptor gamma) that contributes to the mechanism of action of KD and has neuroprotective effects in mammalian TBI models. We found that the incidence of early mortality of Eip75B mutant flies was higher when they were fed KD than when they were fed water following TBI. These data indicate that Eip75B/PPARγ is necessary for the beneficial effects of KD following TBI. In summary, this work provides the first evidence that KD activates PPARγ to reduce deleterious outcomes of TBI and it demonstrates the utility of the fly TBI model for dissecting molecular pathways that contribute to heterogeneity in TBI outcomes.
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Serpa RO, Ferguson L, Larson C, Bailard J, Cooke S, Greco T, Prins ML. Pathophysiology of Pediatric Traumatic Brain Injury. Front Neurol 2021; 12:696510. [PMID: 34335452 PMCID: PMC8319243 DOI: 10.3389/fneur.2021.696510] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/21/2021] [Indexed: 11/23/2022] Open
Abstract
The national incidence of traumatic brain injury (TBI) exceeds that of any other disease in the pediatric population. In the United States the Centers for Disease Control and Prevention (CDC) reports 697,347 annual TBIs in children ages 0–19 that result in emergency room visits, hospitalization or deaths. There is a bimodal distribution within the pediatric TBI population, with peaks in both toddlers and adolescents. Preclinical TBI research provides evidence for age differences in acute pathophysiology that likely contribute to long-term outcome differences between age groups. This review will examine the timecourse of acute pathophysiological processes during cerebral maturation, including calcium accumulation, glucose metabolism and cerebral blood flow. Consequences of pediatric TBI are complicated by the ongoing maturational changes allowing for substantial plasticity and windows of vulnerabilities. This review will also examine the timecourse of later outcomes after mild, repeat mild and more severe TBI to establish developmental windows of susceptibility and altered maturational trajectories. Research progress for pediatric TBI is critically important to reveal age-associated mechanisms and to determine knowledge gaps for future studies.
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Affiliation(s)
- Rebecka O Serpa
- Department of Neurosurgery, Brain Injury Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Steve Tisch BrainSPORT Program, University of California, Los Angeles, Los Angeles, CA, United States
| | - Lindsay Ferguson
- Department of Neurosurgery, Brain Injury Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Steve Tisch BrainSPORT Program, University of California, Los Angeles, Los Angeles, CA, United States
| | - Cooper Larson
- Department of Neurosurgery, Brain Injury Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Steve Tisch BrainSPORT Program, University of California, Los Angeles, Los Angeles, CA, United States
| | - Julie Bailard
- Department of Neurosurgery, Brain Injury Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Steve Tisch BrainSPORT Program, University of California, Los Angeles, Los Angeles, CA, United States
| | - Samantha Cooke
- Department of Neurosurgery, Brain Injury Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Steve Tisch BrainSPORT Program, University of California, Los Angeles, Los Angeles, CA, United States
| | - Tiffany Greco
- Department of Neurosurgery, Brain Injury Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Steve Tisch BrainSPORT Program, University of California, Los Angeles, Los Angeles, CA, United States
| | - Mayumi L Prins
- Department of Neurosurgery, Brain Injury Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Steve Tisch BrainSPORT Program, University of California, Los Angeles, Los Angeles, CA, United States
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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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9
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Yarar-Fisher C, Li J, Womack ED, Alharbi A, Seira O, Kolehmainen KL, Plunet WT, Alaeiilkhchi N, Tetzlaff W. Ketogenic regimens for acute neurotraumatic events. Curr Opin Biotechnol 2021; 70:68-74. [PMID: 33445134 DOI: 10.1016/j.copbio.2020.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/14/2020] [Accepted: 12/07/2020] [Indexed: 12/20/2022]
Abstract
Dietary modification would be the most translatable, cost-efficient, and, likely, the safest approach available that can reduce the reliance on pharmaceutical treatments for treating acute or chronic neurological disorders. A wide variety of evidence suggests that the ketogenic diet (KD) could have beneficial effects in acute traumatic events, such as spinal cord injury and traumatic brain injury. Review of existing human and animal studies revealed that KD can improve motor neuro-recovery, gray matter sparing, pain thresholds, and neuroinflammation and decrease depression. Although the exact mechanism by which the KD provides neuroprotection is not fully understood, its effects on cellular energetics, mitochondria function and inflammation are likely to have a role.
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Affiliation(s)
- Ceren Yarar-Fisher
- Department of Physical Medicine and Rehabilitation, School of Medicine, The University of Alabama at Birmingham, USA.
| | - Jia Li
- Department of Physical Medicine and Rehabilitation, School of Medicine, The University of Alabama at Birmingham, USA
| | - Erika D Womack
- Department of Physical Medicine and Rehabilitation, School of Medicine, The University of Alabama at Birmingham, USA
| | - Amal Alharbi
- Department of Physical Medicine and Rehabilitation, School of Medicine, The University of Alabama at Birmingham, USA; Graduate Program in School of Health Professions, The University of Alabama at Birmingham, 1716 9th Avenue South Birmingham, AL 35294, USA
| | - Oscar Seira
- International Collaboration on Repair Discoveries, University of British Columbia, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada; Department of Zoology, University of British Columbia, 4200 - 6270 University Blvd, Vancouver, BC V6T 1Z4, Canada
| | - Kathleen L Kolehmainen
- International Collaboration on Repair Discoveries, University of British Columbia, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada; Graduate Program in Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Ward T Plunet
- International Collaboration on Repair Discoveries, University of British Columbia, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada
| | - Nima Alaeiilkhchi
- International Collaboration on Repair Discoveries, University of British Columbia, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada; Graduate Program in Neuroscience, University of British Columbia, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries, University of British Columbia, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada
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McGeown JP, Hume PA, Theadom A, Quarrie KL, Borotkanics R. Nutritional interventions to improve neurophysiological impairments following traumatic brain injury: A systematic review. J Neurosci Res 2020; 99:573-603. [PMID: 33107071 DOI: 10.1002/jnr.24746] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/02/2020] [Accepted: 10/07/2020] [Indexed: 12/25/2022]
Abstract
Traumatic brain injury (TBI) accounts for significant global health burden. Effects of TBI can become chronic even following mild injury. There is a need to develop effective therapies to attenuate the damaging effects of TBI and improve recovery outcomes. This literature review using a priori criteria (PROSPERO; CRD42018100623) summarized 43 studies between January 1998 and July 2019 that investigated nutritional interventions (NUT) delivered with the objective of altering neurophysiological (NP) outcomes following TBI. Risk of bias was assessed for included studies, and NP outcomes recorded. The systematic search resulted in 43 of 3,748 identified studies met inclusion criteria. No studies evaluated the effect of a NUT on NP outcomes of TBI in humans. Biomarkers of morphological changes and apoptosis, oxidative stress, and plasticity, neurogenesis, and neurotransmission were the most evaluated NP outcomes across the 43 studies that used 2,897 animals. The risk of bias was unclear in all reviewed studies due to poorly detailed methodology sections. Taking these limitations into account, anti-oxidants, branched chain amino acids, and ω-3 polyunsaturated fatty acids have shown the most promising pre-clinical results for altering NP outcomes following TBI. Refinement of pre-clinical methodologies used to evaluate effects of interventions on secondary damage of TBI would improve the likelihood of translation to clinical populations.
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Affiliation(s)
- Joshua P McGeown
- Sports Performance Research Institute New Zealand (SPRINZ), Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, New Zealand.,Traumatic Brain Injury Network, Auckland University of Technology, Auckland, New Zealand
| | - Patria A Hume
- Sports Performance Research Institute New Zealand (SPRINZ), Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, New Zealand.,Traumatic Brain Injury Network, Auckland University of Technology, Auckland, New Zealand.,National Institute of Stroke and Applied Neuroscience (NISAN), Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, New Zealand
| | - Alice Theadom
- Traumatic Brain Injury Network, Auckland University of Technology, Auckland, New Zealand.,National Institute of Stroke and Applied Neuroscience (NISAN), Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, New Zealand
| | | | - Robert Borotkanics
- Sports Performance Research Institute New Zealand (SPRINZ), Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, New Zealand
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MRI spectroscopic and tractography studies indicate consequences of long-term ketogenic diet. Brain Struct Funct 2020; 225:2077-2089. [PMID: 32681181 PMCID: PMC7473966 DOI: 10.1007/s00429-020-02111-9] [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: 01/20/2020] [Accepted: 07/02/2020] [Indexed: 01/04/2023]
Abstract
To maintain its functional abilities, the mature brain obtains energy from glucose produced in carbohydrate metabolism. When carbohydrates are eliminated from the diet, the energy comes from the oxidation of fatty acids. In this metabolic state called ketosis, ketone bodies are formed: β-hydroxybutyric acid (bHb), acetone, and acetoacetate as alternative source of energy passing through the blood–brain barrier easily. The ketosis state can be achieved through various strategies like caloric restriction, supplementation with medium-chain triglycerides, intense physical training, or ketogenic diet (KD). Using KD, drug-resistant epilepsy has been successfully treated in children and adults. It can also exert neuroprotective influences in cases of brain damage, glioblastoma multiforme, and Alzheimer's or Parkinson's diseases. Although many possible mechanisms of KD activity have been proposed, newer hypotheses appear with the research progress, mostly characterizing the brain under pathological but not normal conditions. Since different pathological conditions may affect the mechanism of KD action differently, additional research on the normal brain appears reasonable. For this purpose, young adult rats were treated with 4-month-lasting KD. Then, MRI structural measurements, spectroscopy, and tractography were performed. The procedures revealed significant increases in the concentration of glutamine, glutamate, glutathione and NAA, accompanied by changes in the pattern of neuronal connections of the striatum and hippocampal formation. This implies a possible involvement of these structures in the functional changes occurring in the brain after KD application. Thus, the investigations on the normal brain add important details concerning mechanisms underlying KD effects without their possible modification by a pathological status.
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Abstract
Ketogenic diet (KD) is a nutritional regimen characterized by a high-fat and an adequate protein content and a very low carbohydrate level (less than 20 g per day or 5% of total daily energy intake). The insufficient level of carbohydrates forces the body to primarily use fat instead of sugar as a fuel source. Due to its characteristic, KD has often been used to treat metabolic disorders, obesity, cardiovascular disease, and type 2 diabetes. Skeletal muscle constitutes 40% of total body mass and is one of the major sites of glucose disposal. KD is a well-defined approach to induce weight loss, with its role in muscle adaptation and muscle hypertrophy less understood. Considering this lack of knowledge, the aim of this review was to examine the scientific evidence about the effects of KD on muscle hypertrophy. We first described the mechanisms of muscle hypertrophy per se, and secondly, we discussed the characteristics and the metabolic function of KD. Ultimately, we provided the potential mechanism that could explain the influence of KD on skeletal muscle hypertrophy.
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13
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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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