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Luppi AI, Rosas FE, Noonan MP, Mediano PAM, Kringelbach ML, Carhart-Harris RL, Stamatakis EA, Vernon AC, Turkheimer FE. Oxygen and the Spark of Human Brain Evolution: Complex Interactions of Metabolism and Cortical Expansion across Development and Evolution. Neuroscientist 2024; 30:173-198. [PMID: 36476177 DOI: 10.1177/10738584221138032] [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] [Indexed: 02/17/2024]
Abstract
Scientific theories on the functioning and dysfunction of the human brain require an understanding of its development-before and after birth and through maturation to adulthood-and its evolution. Here we bring together several accounts of human brain evolution by focusing on the central role of oxygen and brain metabolism. We argue that evolutionary expansion of human transmodal association cortices exceeded the capacity of oxygen delivery by the vascular system, which led these brain tissues to rely on nonoxidative glycolysis for additional energy supply. We draw a link between the resulting lower oxygen tension and its effect on cytoarchitecture, which we posit as a key driver of genetic developmental programs for the human brain-favoring lower intracortical myelination and the presence of biosynthetic materials for synapse turnover. Across biological and temporal scales, this protracted capacity for neural plasticity sets the conditions for cognitive flexibility and ongoing learning, supporting complex group dynamics and intergenerational learning that in turn enabled improved nutrition to fuel the metabolic costs of further cortical expansion. Our proposed model delineates explicit mechanistic links among metabolism, molecular and cellular brain heterogeneity, and behavior, which may lead toward a clearer understanding of brain development and its disorders.
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Affiliation(s)
- Andrea I Luppi
- Department of Clinical Neurosciences and Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Leverhulme Centre for the Future of Intelligence, University of Cambridge, Cambridge, UK
- The Alan Turing Institute, London, UK
| | - Fernando E Rosas
- Department of Informatics, University of Sussex, Brighton, UK
- Centre for Psychedelic Research, Department of Brain Science, Imperial College London, London, UK
- Centre for Complexity Science, Imperial College London, London, UK
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK
| | - MaryAnn P Noonan
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Pedro A M Mediano
- Department of Psychology, University of Cambridge, Cambridge, UK
- Department of Psychology, Queen Mary University of London, London, UK
- Department of Computing, Imperial College London, London, UK
| | - Morten L Kringelbach
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK
- Center for Music in the Brain, Aarhus University, Aarhus, Denmark
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Robin L Carhart-Harris
- Psychedelics Division-Neuroscape, Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Emmanuel A Stamatakis
- Department of Clinical Neurosciences and Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Anthony C Vernon
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Federico E Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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Vlahoyiannis A, Andreou E, Bargiotas P, Aphamis G, Sakkas GK, Giannaki CD. The effect of chrono-nutritional manipulation of carbohydrate intake on sleep macrostructure: A randomized controlled trial. Clin Nutr 2024; 43:858-868. [PMID: 38367595 DOI: 10.1016/j.clnu.2024.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 01/08/2024] [Accepted: 02/13/2024] [Indexed: 02/19/2024]
Abstract
BACKGROUND & AIMS Over the years, there is a rapid increase in the prevalence of inadequate sleep and its detrimental consequences. Yet, the impact of prolonged nutritional interventions on sleep optimization remains unexplored. To examine the effect of carbohydrate manipulation combined with exercise training on sleep macro-structure. METHODS Forty-two healthy, trained male volunteers were recruited for this study. The 4-week intervention consisted of three groups: i) Sleep Low-No Carbohydrates (SL-NCHO): participants consumed all their carbohydrate intake at regular intervals prior to evening training, ii) Sleep High-Low Glycemic Index (SH-LGI) and iii) Sleep High-High Glycemic Index (SH-HGI): Carbohydrate intake was spread throughout the day, both prior (60% of total CHO intake) and after evening training (40% of total CHO intake). The SH-LGI and SH-HGI groups differentiated by consuming either LGI or HGI foods in the evening, respectively. Alongside, participants performed a standardized exercise program combining resistance exercise and high-intensity interval training. Participants' sleep macro-structure was assessed with polysomnography, actigraphy, sleep diary, and sleep-wake questionnaires. RESULTS Objective assessments revealed a substantial time-effect on sleep initiation, duration, and continuity. After the intervention, sleep onset latency decreased (p < 0.001), sleep duration was prolonged (p = 0.006), sleep efficiency increased (p < 0.001), and wake after sleep onset decreased (p = 0.035). Sleep macroarchitecture did not significantly change, while the percentage of REM sleep stage to the total sleep time increased over time (p < 0.01). Consistent with the objective findings, subjects reported improved subjective sleep quality (p = 0.043) and reduced daytime sleepiness (p = 0.047). CONCLUSION The combination of a personalized dietary plan with exercise training enhances sleep initiation, sleep continuity, sleep duration, REM and N1 sleep stages, independently of carbohydrate type or timing. Lifestyle interventions should be investigated further to promote sleep quality and recovery. REGISTRATION The trial was registered at clinicaltrials.gov as NCT05464342.
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Affiliation(s)
- Angelos Vlahoyiannis
- Department of Life Sciences, University of Nicosia, Nicosia, Cyprus; Research Centre for Exercise and Nutrition (RECEN), University of Nicosia, Nicosia, Cyprus
| | - Eleni Andreou
- Department of Life Sciences, University of Nicosia, Nicosia, Cyprus; Research Centre for Exercise and Nutrition (RECEN), University of Nicosia, Nicosia, Cyprus
| | | | - George Aphamis
- Department of Life Sciences, University of Nicosia, Nicosia, Cyprus; Research Centre for Exercise and Nutrition (RECEN), University of Nicosia, Nicosia, Cyprus
| | - Giorgos K Sakkas
- Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Christoforos D Giannaki
- Department of Life Sciences, University of Nicosia, Nicosia, Cyprus; Research Centre for Exercise and Nutrition (RECEN), University of Nicosia, Nicosia, Cyprus.
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Xu J, Wiemken A, Langham MC, Rao H, Nabbout M, Caporale AS, Schwab RJ, Detre JA, Wehrli FW. Sleep-stage-dependent alterations in cerebral oxygen metabolism quantified by magnetic resonance. J Neurosci Res 2024; 102:e25313. [PMID: 38415989 DOI: 10.1002/jnr.25313] [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: 08/10/2023] [Revised: 01/25/2024] [Accepted: 02/09/2024] [Indexed: 02/29/2024]
Abstract
A key function of sleep is to provide a regular period of reduced brain metabolism, which is critical for maintenance of healthy brain function. The purpose of this work was to quantify the sleep-stage-dependent changes in brain energetics in terms of cerebral metabolic rate of oxygen (CMRO2 ) as a function of sleep stage using quantitative magnetic resonance imaging (MRI) with concurrent electroencephalography (EEG) during sleep in the scanner. Twenty-two young and older subjects with regular sleep hygiene and Pittsburgh Sleep Quality Index (PSQI) in the normal range were recruited for the study. Cerebral blood flow (CBF) and venous oxygen saturation (SvO2 ) were obtained simultaneously at 3 Tesla field strength and 2.7-s temporal resolution during an 80-min time series using OxFlow, an in-house developed imaging sequence. The method yields whole-brain CMRO2 in absolute physiologic units via Fick's Principle. Nineteen subjects yielded evaluable data free of subject motion artifacts. Among these subjects, 10 achieved slow-wave (N3) sleep, 16 achieved N2 sleep, and 19 achieved N1 sleep while undergoing the MRI protocol during scanning. Mean CMRO2 was 98 ± 7(μmol min-1 )/100 g awake, declining progressively toward deepest sleep stage: 94 ± 10.8 (N1), 91 ± 11.4 (N2), and 76 ± 9.0 μmol min-1 /100 g (N3), with each level differing significantly from the wake state. The technology described is able to quantify cerebral oxygen metabolism in absolute physiologic units along with non-REM sleep stage, indicating brain oxygen consumption to be closely associated with depth of sleep, with deeper sleep stages exhibiting progressively lower CMRO2 levels.
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Affiliation(s)
- Jing Xu
- Laboratory for Structural, Physiological, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrew Wiemken
- Division of Sleep Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael C Langham
- Laboratory for Structural, Physiological, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hengyi Rao
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marianne Nabbout
- Laboratory for Structural, Physiological, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Alessandra S Caporale
- Laboratory for Structural, Physiological, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Neurosciences, Imaging and Clinical Sciences, 'G. d'Annunzio University' of Chieti-Pescara, Chieti, Italy
- Institute for Advanced Biomedical Technologies (ITAB), 'G. d'Annunzio University' of Chieti-Pescara, Chieti, Italy
| | - Richard J Schwab
- Division of Sleep Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John A Detre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Felix W Wehrli
- Laboratory for Structural, Physiological, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Neculicioiu VS, Colosi IA, Costache C, Toc DA, Sevastre-Berghian A, Colosi HA, Clichici S. Sleep Deprivation-Induced Oxidative Stress in Rat Models: A Scoping Systematic Review. Antioxidants (Basel) 2023; 12:1600. [PMID: 37627596 PMCID: PMC10451248 DOI: 10.3390/antiox12081600] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 08/01/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Sleep deprivation is highly prevalent in the modern world, possibly reaching epidemic proportions. While multiple theories regarding the roles of sleep exist (inactivity, energy conservation, restoration, brain plasticity and antioxidant), multiple unknowns still remain regarding the proposed antioxidant roles of sleep. The existing experimental evidence is often contradicting, with studies pointing both toward and against the presence of oxidative stress after sleep deprivation. The main goals of this review were to analyze the existing experimental data regarding the relationship between sleep deprivation and oxidative stress, to attempt to further clarify multiple aspects surrounding this relationship and to identify current knowledge gaps. Systematic searches were conducted in three major online databases for experimental studies performed on rat models with oxidative stress measurements, published between 2015 and 2022. A total of 54 studies were included in the review. Most results seem to point to changes in oxidative stress parameters after sleep deprivation, further suggesting an antioxidant role of sleep. Alterations in these parameters were observed in both paradoxical and total sleep deprivation protocols and in multiple rat strains. Furthermore, the effects of sleep deprivation seem to extend beyond the central nervous system, affecting multiple other body sites in the periphery. Sleep recovery seems to be characterized by an increased variability, with the presence of both normalizations in some parameters and long-lasting changes after sleep deprivation. Surprisingly, most studies revealed the presence of a stress response following sleep deprivation. However, the origin and the impact of the stress response during sleep deprivation remain somewhat unclear. While a definitive exclusion of the influence of the sleep deprivation protocol on the stress response is not possible, the available data seem to suggest that the observed stress response may be determined by sleep deprivation itself as opposed to the experimental conditions. Due to this fact, the observed oxidative changes could be attributed directly to sleep deprivation.
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Affiliation(s)
- Vlad Sever Neculicioiu
- Department of Microbiology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Ioana Alina Colosi
- Department of Microbiology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Carmen Costache
- Department of Microbiology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Dan Alexandru Toc
- Department of Microbiology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Alexandra Sevastre-Berghian
- Department of Physiology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania
| | - Horațiu Alexandru Colosi
- Division of Medical Informatics and Biostatistics, Department of Medical Education, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Simona Clichici
- Department of Physiology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania
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St-Onge MP, Cherta-Murillo A, Darimont C, Mantantzis K, Martin FP, Owen L. The interrelationship between sleep, diet, and glucose metabolism. Sleep Med Rev 2023; 69:101788. [PMID: 37156196 PMCID: PMC10247426 DOI: 10.1016/j.smrv.2023.101788] [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: 01/05/2023] [Revised: 03/28/2023] [Accepted: 04/23/2023] [Indexed: 05/10/2023]
Abstract
Obesity and type 2 diabetes (T2D) are increasingly common worldwide. While these disorders have increased in prevalence over the past several decades, there has been a concomitant reduction in sleep duration. Short sleep duration has been associated with higher rates of obesity and T2D, and the causality of these associations and their directionality, continue to necessitate evaluation. In this review we consider the evidence that sleep is an intrinsic factor in the development of obesity and chronic metabolic disorders, such as insulin resistance and T2D, while evaluating a potential bi-directional association. We consider the evidence that diet and meal composition, which are known to impact glycemic control, may have both chronic and acute impact upon sleep. Moreover, we consider that postprandial nocturnal metabolism and peripheral glycemia may affect sleep quality. We propose putative mechanisms whereby acute effects of nighttime glucose excursions may lead to increased sleep fragmentation. We conclude that dietary manipulations, particularly with respect to carbohydrate quality, may confer sleep benefits. Future research may seek to evaluate the effectiveness of synergistic nutrient strategies to promote sleep quality, with particular attention to carbohydrate quality, quantity, and availability as well as carbohydrate to protein ratio.
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Affiliation(s)
- Marie-Pierre St-Onge
- Division of General Medicine and Center of Excellence for Sleep & Circadian Research, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA.
| | | | - Christian Darimont
- Nestlé Research, Nestlé Institute of Health Sciences, Lausanne, Switzerland
| | | | | | - Lauren Owen
- Nestlé Research, Nestlé Institute of Health Sciences, Lausanne, Switzerland
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Peters A, Sprengell M, Kubera B. The principle of 'brain energy on demand' and its predictive power for stress, sleep, stroke, obesity and diabetes. Neurosci Biobehav Rev 2022; 141:104847. [PMID: 36067964 DOI: 10.1016/j.neubiorev.2022.104847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 08/10/2022] [Accepted: 08/26/2022] [Indexed: 12/01/2022]
Abstract
Does the brain actively draw energy from the body when needed? There are different schools of thought regarding energy metabolism. In this study, the various theoretical models are classified into one of two categories: (1) conceptualizations of the brain as being purely passively supplied, which we call 'P-models,' and (2) models understanding the brain as not only passively receiving energy but also actively procuring energy for itself on demand, which we call 'A-models.' One prominent example of such theories making use of an A-model is the selfish-brain theory. The ability to make predictions was compared between the A- and P-models. A-models were able to predict and coherently explain all data examined, which included stress, sleep, caloric restriction, stroke, type-1-diabetes mellitus, obesity, and type-2-diabetes, whereas the predictions of P-models failed in most cases. The strength of the evidence supporting A-models is based on the coherence of accurate predictions across a spectrum of metabolic states. The theory test conducted here speaks to a brain that pulls its energy from the body on-demand.
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Affiliation(s)
- Achim Peters
- Medical Clinic 1, Center of Brain, Behavior and Metabolism, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
| | - Marie Sprengell
- Medical Clinic 1, Center of Brain, Behavior and Metabolism, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Britta Kubera
- Medical Clinic 1, Center of Brain, Behavior and Metabolism, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
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Kontou TG, Sargent C, Roach GD. A Week of Sleep Restriction Does Not Affect Nighttime Glucose Concentration in Healthy Adult Males When Slow-Wave Sleep Is Maintained. SENSORS (BASEL, SWITZERLAND) 2022; 22:6962. [PMID: 36146310 PMCID: PMC9500600 DOI: 10.3390/s22186962] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
The aim of this laboratory-based study was to examine the effect of sleep restriction on glucose regulation during nighttime sleep. Healthy males were randomly assigned to one of two conditions: 9 h in bed (n = 23, age = 24.0 year) or 5 h in bed (n = 18, age = 21.9 year). Participants had a baseline night with 9 h in bed (23:00-08:00 h), then seven nights of 9 h (23:00-08:00 h) or 5 h (03:00-08:00 h) in bed. Participants were mostly seated during the daytime but had three bouts of treadmill walking (4 km·h-1 for 10 min) at ~14:40 h, ~17:40 h, and ~20:40 h each day. On the baseline night and night seven, glucose concentration in interstitial fluid was assessed by using continuous glucose monitors, and sleep was assessed by using polysomnography. On night seven, compared to the 9 h group, the 5 h group obtained less total sleep (292 min vs. 465 min) and less REM sleep (81 min vs. 118 min), but their slow-wave sleep did not differ (119 min vs. 120 min), and their glucose concentration during sleep did not differ (5.1 mmol·L-1 vs. 5.1 mmol·L-1). These data indicate that sleep restriction does not cause elevated levels of circulating glucose during nighttime sleep when slow-wave sleep is maintained. In the future, it will be important to determine whether increased insulin is required to maintain circulating glucose at a normal level when sleep is restricted.
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Peters A, Hartwig M, Spiller T. Obesity and Type 2 Diabetes Mellitus Explained by the Free Energy Principle. Front Psychol 2022; 13:931701. [PMID: 35756264 PMCID: PMC9226719 DOI: 10.3389/fpsyg.2022.931701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
According to the free energy principle, all sentient beings strive to minimize surprise or, in other words, an information-theoretical quantity called variational free energy. Consequently, psychosocial “stress” can be redefined as a state of “heightened expected free energy,” that is, a state of “expected surprise” or “uncertainty.” Individuals experiencing stress primarily attempt to reduce uncertainty, or expected free energy, with the help of what is called an uncertainty resolution program (URP). The URP consists of three subroutines: First, an arousal state is induced that increases cerebral information transmission and processing to reduce uncertainty as quickly as possible. Second, these additional computations cost the brain additional energy, which it demands from the body. Third, the program controls which stress reduction measures are learned for future use and which are not. We refer to an episode as “good” stress, when the URP has successfully reduced uncertainty. Failure of the URP to adequately reduce uncertainty results in either stress habituation or prolonged toxic stress. Stress habituation reduces uncertainty by flattening/broadening individual goal beliefs so that outcomes previously considered as untenable become acceptable. Habituated individuals experience so-called “tolerable” stress. Referring to the Selfish Brain theory and the experimental evidence supporting it, we show that habituated people, who lack stress arousals and therefore have decreased average brain energy consumption, tend to develop an obese type 2 diabetes mellitus phenotype. People, for whom habituation is not the free-energy-optimal solution, do not reduce their uncertainty by changing their goal preferences, and are left with nothing but “toxic” stress. Toxic stress leads to recurrent or persistent arousal states and thus increased average brain energy consumption, which in turn promotes the development of a lean type 2 diabetes mellitus phenotype. In conclusion, we anchor the psychosomatic concept of stress in the information-theoretical concept of uncertainty as defined by the free energy principle. In addition, we detail the neurobiological mechanisms underlying uncertainty reduction and illustrate how uncertainty can lead to psychosomatic illness.
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Affiliation(s)
- Achim Peters
- Medical Clinic 1, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, Germany
| | - Mattis Hartwig
- German Research Center for Artificial Intelligence (DFKI), Kaiserslautern, Germany.,singularIT GmbH, Leipzig, Germany
| | - Tobias Spiller
- Department of Consultation-Liaison Psychiatry and Psychosomatic Medicine, University Hospital Zurich, Zurich, Switzerland.,Faculty of Medicine, University of Zurich, Zurich, Switzerland
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Herculano-Houzel S, Rothman DL. From a Demand-Based to a Supply-Limited Framework of Brain Metabolism. Front Integr Neurosci 2022; 16:818685. [PMID: 35431822 PMCID: PMC9012138 DOI: 10.3389/fnint.2022.818685] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/10/2022] [Indexed: 12/20/2022] Open
Abstract
What defines the rate of energy use by the brain, as well as per neurons of different sizes in different structures and animals, is one fundamental aspect of neuroscience for which much has been theorized, but very little data are available. The prevalent theories and models consider that energy supply from the vascular system to different brain regions is adjusted both dynamically and in the course of development and evolution to meet the demands of neuronal activity. In this perspective, we offer an alternative view: that regional rates of energy use might be mostly constrained by supply, given the properties of the brain capillary network, the highly stable rate of oxygen delivery to the whole brain under physiological conditions, and homeostatic constraints. We present evidence that these constraints, based on capillary density and tissue oxygen homeostasis, are similar between brain regions and mammalian species, suggesting they derive from fundamental biophysical limitations. The same constraints also determine the relationship between regional rates of brain oxygen supply and usage over the full physiological range of brain activity, from deep sleep to intense sensory stimulation, during which the apparent uncoupling of blood flow and oxygen use is still a predicted consequence of supply limitation. By carefully separating "energy cost" into energy supply and energy use, and doing away with the problematic concept of energetic "demands," our new framework should help shine a new light on the neurovascular bases of metabolic support of brain function and brain functional imaging. We speculate that the trade-offs between functional systems and even the limitation to a single attentional spot at a time might be consequences of a strongly supply-limited brain economy. We propose that a deeper understanding of brain energy supply constraints will provide a new evolutionary understanding of constraints on brain function due to energetics; offer new diagnostic insight to disturbances of brain metabolism; lead to clear, testable predictions on the scaling of brain metabolic cost and the evolution of brains of different sizes; and open new lines of investigation into the microvascular bases of progressive cognitive loss in normal aging as well as metabolic diseases.
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Affiliation(s)
- Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, TN, United States,Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States,*Correspondence: Suzana Herculano-Houzel,
| | - Douglas L. Rothman
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, United States,Department of Biomedical Engineering, Yale University, New Haven, CT, United States,Magnetic Resonance Research Center, Yale University, New Haven, CT, United States
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10
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Effect of chronic sleep deprivation and sleep recovery on hippocampal CA3 neurons, spatial memory and anxiety-like behavior in rats. Neurobiol Learn Mem 2021; 187:107559. [PMID: 34808338 DOI: 10.1016/j.nlm.2021.107559] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 11/12/2021] [Accepted: 11/14/2021] [Indexed: 11/24/2022]
Abstract
Sleep deprivation-induced degenerative changes in the brain lead to the impairment of memory, anxiety, and quality of life. Several studies have reported the effects of sleep deprivation on CA1 and dentate gyrus regions of the hippocampus; in contrast, there is less known about the impact of chronic sleep deprivation (CSD) and sleep recovery on CA3 neurons and behavior. Hence, the present study aimed to understand the effect of CSD and sleep recovery on hippocampal CA3 neurons and spatial memory, and anxiety-like behavior in rats. Sixty male rats (Sprague Dawley) were grouped as control, environmental control (EC), CSD, 5 days sleep recovery (CSD + 5D SR), and 21 days sleep recovery (CSD + 21D SR). CSD, CSD + 5D SR and, CSD + 21D SR group rats were sleep deprived for 21 days (18 h/day). After CSD, the CSD + 5D SR and CSD + 21D SR rats were sleep recovered for 5- and 21-days respectively. Oxidative stress, dendritic arborization of CA3 neurons, spatial memory, and anxiety-like behavior was assessed. Spatial memory, basal, and apical dendritic branching points/intersections in hippocampal CA3 neurons were reduced, and anxiety-like behavior and oxidative stress increased significantly in the CSD group compared to control (p < 0.001). The CSD + 21D SR showed a significant improvement in spatial memory, reduction in anxiety-like behavior, and oxidative stress when compared to the CSD group (p < 0.05). The basal and apical dendritic branching points/intersections in hippocampal CA3 neurons were increased after CSD + 21D SR, however, it was not significant (p > 0.05). Even though the CSD + 21D SR showed a significant improvement in all the parameters, it did not reach the control level. There was an improvement in all the parameters after CSD + 5D SR but this was not significant compared to the CSD group (p > 0.05). Overall results indicate that the CSD-induced impairment of spatial memory and anxiety-like behavior was associated with oxidative stress and reduced dendritic arborization of hippocampal CA3 neurons. The CSD + 21D SR significantly reduced the damage caused by CSD, but it was not sufficient to reach the control level.
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11
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Circadian Clocks, Sleep, and Metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 34773224 DOI: 10.1007/978-3-030-81147-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
A molecular circadian clock exists not only in the brain, but also in most cells of the body. Research over the past two decades has demonstrated that it directs daily rhythmicity of nearly every aspect of metabolism. It also consolidates sleep-wake behavior each day into an activity/feeding period and a sleep/fasting period. Otherwise, sleep-wake states are mostly controlled by hypothalamic and thalamic regulatory circuits in the brain that direct overall brain state. Recent evidence suggests that hypothalamic control of appetite and metabolism may be concomitant with sleep-wake regulation, and even share the same control centers. Thus, circadian control of metabolic pathways might be overlaid by sleep-wake control of the same pathways, providing a flexible and redundant system to modify metabolism according to both activity and environment.
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van Aalst J, Ceccarini J, Sunaert S, Dupont P, Koole M, Van Laere K. In vivo synaptic density relates to glucose metabolism at rest in healthy subjects, but is strongly modulated by regional differences. J Cereb Blood Flow Metab 2021; 41:1978-1987. [PMID: 33444094 PMCID: PMC8327121 DOI: 10.1177/0271678x20981502] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Preclinical and postmortem studies have suggested that regional synaptic density and glucose consumption (CMRGlc) are strongly related. However, the relation between synaptic density and cerebral glucose metabolism in the human brain has not directly been assessed in vivo. Using [11C]UCB-J binding to synaptic vesicle glycoprotein 2 A (SV2A) as indicator for synaptic density and [18F]FDG for measuring cerebral glucose consumption, we studied twenty healthy female subjects (age 29.6 ± 9.9 yrs) who underwent a single-day dual-tracer protocol (GE Signa PET-MR). Global measures of absolute and relative CMRGlc and specific binding of [11C]UCB-J were indeed highly significantly correlated (r > 0.47, p < 0.001). However, regional differences in relative [18F]FDG and [11C]UCB-J uptake were observed, with up to 19% higher [11C]UCB-J uptake in the medial temporal lobe (MTL) and up to 17% higher glucose metabolism in frontal and motor-related areas and thalamus. This pattern has a considerable overlap with the brain regions showing different levels of aerobic glycolysis. Regionally varying energy demands of inhibitory and excitatory synapses at rest may also contribute to this difference. Being unaffected by astroglial and/or microglial energy demands, changes in synaptic density in the MTL may therefore be more sensitive to early detection of pathological conditions compared to changes in glucose metabolism.
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Affiliation(s)
- June van Aalst
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Jenny Ceccarini
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Stefan Sunaert
- Translational MRI, Department of Imaging and Pathology, Leuven, Belgium.,Radiology, UZ Leuven, Leuven, Belgium
| | - Patrick Dupont
- Laboratory for Cognitive Neurology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,Nuclear Medicine, UZ Leuven, Leuven, Belgium
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13
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Moore MC, Warner SO, Dai Y, Sheanon N, Smith M, Farmer B, Cason RL, Cherrington AD, Winnick JJ. C-peptide enhances glucagon secretion in response to hyperinsulinemia under euglycemic and hypoglycemic conditions. JCI Insight 2021; 6:148997. [PMID: 34003799 PMCID: PMC8262495 DOI: 10.1172/jci.insight.148997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 05/12/2021] [Indexed: 12/17/2022] Open
Abstract
Several studies have associated the presence of residual insulin secretion capability (also referred to as being C-peptide positive) with lower risk of insulin-induced hypoglycemia in patients with type 1 diabetes (T1D), although the reason is unclear. We tested the hypothesis that C-peptide infusion would enhance glucagon secretion in response to hyperinsulinemia during euglycemic and hypoglycemic conditions in dogs (5 male/4 female). After a 2-hour basal period, an intravenous (IV) infusion of insulin was started, and dextrose was infused to maintain euglycemia for 2 hours. At the same time, an IV infusion of either saline (SAL) or C-peptide (CPEP) was started. After this euglycemic period, the insulin and SAL/CPEP infusions were continued for another 2 hours, but the glucose was allowed to fall to approximately 50 mg/dL. In response to euglycemic-hyperinsulinemia, glucagon secretion decreased in SAL but remained unchanged from the basal period in CPEP condition. During hypoglycemia, glucagon secretion in CPEP was 2 times higher than SAL, and this increased net hepatic glucose output and reduced the amount of exogenous glucose required to maintain glycemia. These data suggest that the presence of C-peptide during IV insulin infusion can preserve glucagon secretion during euglycemia and enhance it during hypoglycemia, which could explain why T1D patients with residual insulin secretion are less susceptible to hypoglycemia.
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Affiliation(s)
- Mary Courtney Moore
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Shana O. Warner
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Yufei Dai
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Nicole Sheanon
- Department of Endocrinology, University of Cincinnati College of Medicine and Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Rebecca L. Cason
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Alan D. Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jason J. Winnick
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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14
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Levy WB, Calvert VG. Communication consumes 35 times more energy than computation in the human cortex, but both costs are needed to predict synapse number. Proc Natl Acad Sci U S A 2021; 118:e2008173118. [PMID: 33906943 PMCID: PMC8106317 DOI: 10.1073/pnas.2008173118] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Darwinian evolution tends to produce energy-efficient outcomes. On the other hand, energy limits computation, be it neural and probabilistic or digital and logical. Taking a particular energy-efficient viewpoint, we define neural computation and make use of an energy-constrained computational function. This function can be optimized over a variable that is proportional to the number of synapses per neuron. This function also implies a specific distinction between adenosine triphosphate (ATP)-consuming processes, especially computation per se vs. the communication processes of action potentials and transmitter release. Thus, to apply this mathematical function requires an energy audit with a particular partitioning of energy consumption that differs from earlier work. The audit points out that, rather than the oft-quoted 20 W of glucose available to the human brain, the fraction partitioned to cortical computation is only 0.1 W of ATP [L. Sokoloff, Handb. Physiol. Sect. I Neurophysiol. 3, 1843-1864 (1960)] and [J. Sawada, D. S. Modha, "Synapse: Scalable energy-efficient neurosynaptic computing" in Application of Concurrency to System Design (ACSD) (2013), pp. 14-15]. On the other hand, long-distance communication costs are 35-fold greater, 3.5 W. Other findings include 1) a [Formula: see text]-fold discrepancy between biological and lowest possible values of a neuron's computational efficiency and 2) two predictions of N, the number of synaptic transmissions needed to fire a neuron (2,500 vs. 2,000).
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Affiliation(s)
- William B Levy
- Department of Neurosurgery, University of Virginia, Charlottesville, VA 22908;
- Department of Psychology, University of Virginia, Charlottesville, VA 22904
| | - Victoria G Calvert
- College of Arts and Sciences, University of Virginia, Charlottesville, VA 22903
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15
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Soon CS, Vinogradova K, Ong JL, Calhoun VD, Liu T, Zhou JH, Ng KK, Chee MWL. Respiratory, cardiac, EEG, BOLD signals and functional connectivity over multiple microsleep episodes. Neuroimage 2021; 237:118129. [PMID: 33951513 DOI: 10.1016/j.neuroimage.2021.118129] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/04/2021] [Accepted: 04/28/2021] [Indexed: 01/16/2023] Open
Abstract
Falling asleep is common in fMRI studies. By using long eyelid closures to detect microsleep onset, we showed that the onset and termination of short sleep episodes invokes a systematic sequence of BOLD signal changes that are large, widespread, and consistent across different microsleep durations. The signal changes are intimately intertwined with shifts in respiration and heart rate, indicating that autonomic contributions are integral to the brain physiology evaluated using fMRI and cannot be simply treated as nuisance signals. Additionally, resting state functional connectivity (RSFC) was altered in accord with the frequency of falling asleep and in a manner that global signal regression does not eliminate. Our findings point to the need to develop a consensus among neuroscientists using fMRI on how to deal with microsleep intrusions. SIGNIFICANCE STATEMENT: Sleep, breathing and cardiac action are influenced by common brainstem nuclei. We show that falling asleep and awakening are associated with a sequence of BOLD signal changes that are large, widespread and consistent across varied durations of sleep onset and awakening. These signal changes follow closely those associated with deceleration and acceleration of respiration and heart rate, calling into question the separation of the latter signals as 'noise' when the frequency of falling asleep, which is commonplace in RSFC studies, correlates with the extent of RSFC perturbation. Autonomic and central nervous system contributions to BOLD signal have to be jointly considered when interpreting fMRI and RSFC studies.
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Affiliation(s)
- Chun Siong Soon
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Centre for Translational MR Imaging, Yong Loo Lin School of Medicine, National Unviersity of Singapore, Singapore.
| | - Ksenia Vinogradova
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ju Lynn Ong
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Vince D Calhoun
- Tri-institutional Center for Translational Research in Neuroimaging and Data Science (TReNDS), Georgia State, Georgia Tech, Emory, Atlanta, USA
| | - Thomas Liu
- UCSD Center for Functional MRI and Department of Radiology, UC San Diego School of Medicine, La Jolla, CA, USA
| | - Juan Helen Zhou
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Centre for Translational MR Imaging, Yong Loo Lin School of Medicine, National Unviersity of Singapore, Singapore
| | - Kwun Kei Ng
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Michael W L Chee
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Centre for Translational MR Imaging, Yong Loo Lin School of Medicine, National Unviersity of Singapore, Singapore.
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16
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Warner SO, Wadian AM, Smith M, Farmer B, Dai Y, Sheanon N, Edgerton DS, Winnick JJ. Liver glycogen-induced enhancements in hypoglycemic counterregulation require neuroglucopenia. Am J Physiol Endocrinol Metab 2021; 320:E914-E924. [PMID: 33779306 PMCID: PMC8424545 DOI: 10.1152/ajpendo.00501.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 01/24/2023]
Abstract
Iatrogenic hypoglycemia is a prominent barrier to achieving optimal glycemic control in patients with diabetes, in part due to dampened counterregulatory hormone responses. It has been demonstrated that elevated liver glycogen content can enhance these hormonal responses through signaling to the brain via afferent nerves, but the role that hypoglycemia in the brain plays in this liver glycogen effect remains unclear. During the first 4 h of each study, the liver glycogen content of dogs was increased by using an intraportal infusion of fructose to stimulate hepatic glucose uptake (HG; n = 13), or glycogen was maintained near fasting levels with a saline infusion (NG; n = 6). After a 2-h control period, during which the fructose/saline infusion was discontinued, insulin was infused intravenously for an additional 2 h to bring about systemic hypoglycemia in all animals, whereas brain euglycemia was maintained in a subset of the HG group by infusing glucose bilaterally into the carotid and vertebral arteries (HG-HeadEu; n = 7). Liver glycogen content was markedly elevated in the two HG groups (43 ± 4, 73 ± 3, and 75 ± 7 mg/g in NG, HG, and HG-HeadEu, respectively). During the hypoglycemic period, arterial plasma glucose levels were indistinguishable between groups (53 ± 2, 52 ± 1, and 51 ± 1 mg/dL, respectively), but jugular vein glucose levels were kept euglycemic (88 ± 5 mg/dL) only in the HG-HeadEu group. Glucagon and epinephrine responses to hypoglycemia were higher in HG compared with NG, whereas despite the increase in liver glycogen, neither increased above basal in HG-HeadEu. These data demonstrate that the enhanced counterregulatory hormone secretion that accompanies increased liver glycogen content requires hypoglycemia in the brain.NEW & NOTEWORTHY It is well known that iatrogenic hypoglycemia is a barrier to optimal glycemic regulation in patients with diabetes. Our data confirm that increasing liver glycogen content 75% above fasting levels enhances hormonal responses to insulin-induced hypoglycemia and demonstrate that this enhanced hormonal response does not occur in the absence of hypoglycemia in the brain. These data demonstrate that information from the liver regarding glycogen availability is integrated in the brain to optimize the counterregulatory response.
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Affiliation(s)
- Shana O Warner
- Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Abby M Wadian
- Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Marta Smith
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Ben Farmer
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Yufei Dai
- Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Nicole Sheanon
- Department of Endocrinology, University of Cincinnati College of Medicine and Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Dale S Edgerton
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Jason J Winnick
- Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
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17
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Vlahoyiannis A, Giannaki CD, Sakkas GK, Aphamis G, Andreou E. A Systematic Review, Meta-Analysis and Meta-Regression on the Effects of Carbohydrates on Sleep. Nutrients 2021; 13:nu13041283. [PMID: 33919698 PMCID: PMC8069918 DOI: 10.3390/nu13041283] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 02/02/2023] Open
Abstract
This study aimed to assess the effects of quantity, quality and periodization of carbohydrates consumption on sleep. PubMed, SCOPUS and Cochrane Library were searched through October 2020. Data were pooled using random-effects meta-analysis. Eleven articles were included in the meta-analysis which consisted of 27 separate nutrition trials, resulting in 16 comparison data sets (sleep quantity n = 11; sleep quality n = 5). Compared to high carbohydrate (HCI), low carbohydrate intake (LCI) moderately increased duration and proportion of N3 sleep stage (ES = 0.37; 95% CI = 0.18, 0.56; p < 0.001 and ES = 0.51; 95% CI = 0.33, 0.69; p < 0.001, respectively). HCI prolonged rapid eye movement (REM) stage duration (ES = −0.38; 95% CI = 0.05, −8.05; p < 0.001) and proportion (ES = −0.46; 95% CI = −0.83, −0.01; p < 0.001), compared to LCI. The quality of carbohydrate intake did not affect sleep stages. Meta-regression showed that the effectiveness of carbohydrate quantity and quality in sleep onset latency was significantly explained by alterations of carbohydrate intake as a percentage of daily energy intake (R2 = 25.87, p = 0.018) and alterations in the glycemic load (R2 = 50.8, p = 0.048), respectively. Alterations in glycemic load partially explained the variance of the effectiveness of carbohydrate quality in sleep efficiency (R2 = 89.2, p < 0.001) and wake after sleep onset (R2 = 64.9, p = 0.018). Carbohydrate quantity was shown to affect sleep architecture, and especially N3 and REM sleep stages. Alterations in both quantity and quality of carbohydrate intake showed a significant effect on sleep initiation. Variations in carbohydrate quality significantly affected measures of sleep continuation. Further studies are needed to assess the effect of long-term carbohydrate interventions on sleep.
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Affiliation(s)
- Angelos Vlahoyiannis
- Department of Life and Health Sciences, University of Nicosia, 46 Makedonitisas Avenue, Nicosia CY1700, Cyprus; (A.V.); (C.D.G.); (G.A.)
| | - Christoforos D. Giannaki
- Department of Life and Health Sciences, University of Nicosia, 46 Makedonitisas Avenue, Nicosia CY1700, Cyprus; (A.V.); (C.D.G.); (G.A.)
| | - Giorgos K. Sakkas
- Department of PE and Sport Science, University of Thessaly, 42100 Trikala, Greece;
- School of Sports and Health Sciences, Cardiff Metropolitan University, Llandaff Campus, Western Avenue, Cardiff CF5 2YB, Wales, UK
| | - George Aphamis
- Department of Life and Health Sciences, University of Nicosia, 46 Makedonitisas Avenue, Nicosia CY1700, Cyprus; (A.V.); (C.D.G.); (G.A.)
| | - Eleni Andreou
- Department of Life and Health Sciences, University of Nicosia, 46 Makedonitisas Avenue, Nicosia CY1700, Cyprus; (A.V.); (C.D.G.); (G.A.)
- Correspondence: ; Tel.: +357-22452288; Fax: +357-22452292
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18
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Caporale A, Lee H, Lei H, Rao H, Langham MC, Detre JA, Wu PH, Wehrli FW. Cerebral metabolic rate of oxygen during transition from wakefulness to sleep measured with high temporal resolution OxFlow MRI with concurrent EEG. J Cereb Blood Flow Metab 2021; 41:780-792. [PMID: 32538283 PMCID: PMC7983504 DOI: 10.1177/0271678x20919287] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 03/03/2020] [Accepted: 03/20/2020] [Indexed: 01/29/2023]
Abstract
During slow-wave sleep, synaptic transmissions are reduced with a concomitant reduction in brain energy consumption. We used 3 Tesla MRI to noninvasively quantify changes in the cerebral metabolic rate of O2 (CMRO2) during wakefulness and sleep, leveraging the 'OxFlow' method, which provides venous O2 saturation (SvO2) along with cerebral blood flow (CBF). Twelve healthy subjects (31.3 ± 5.6 years, eight males) underwent 45-60 min of continuous scanning during wakefulness and sleep, yielding one image set every 3.4 s. Concurrent electroencephalography (EEG) data were available in eight subjects. Mean values of the metabolic parameters measured during wakefulness were stable, with coefficients of variation below 7% (average values: CMRO2 = 118 ± 12 µmol O2/min/100 g, SvO2 = 67.0 ± 3.7% HbO2, CBF = 50.6 ±4.3 ml/min/100 g). During sleep, on average, CMRO2 decreased 21% (range: 14%-32%; average nadir = 98 ± 16 µmol O2/min/100 g), while EEG slow-wave activity, expressed in terms of δ -power, increased commensurately. Following sleep onset, CMRO2 was found to correlate negatively with relative δ -power (r = -0.6 to -0.8, P < 0.005), and positively with heart rate (r = 0.5 to 0.8, P < 0.0005). The data demonstrate that OxFlow MRI can noninvasively measure dynamic changes in cerebral metabolism associated with sleep, which should open new opportunities to study sleep physiology in health and disease.
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Affiliation(s)
- Alessandra Caporale
- Laboratory for Structural Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Perelman School of Medicine, PA, USA
| | - Hyunyeol Lee
- Laboratory for Structural Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Perelman School of Medicine, PA, USA
| | - Hui Lei
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Hengyi Rao
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
- Division of Sleep and Chronobiology, Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Michael C Langham
- Laboratory for Structural Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Perelman School of Medicine, PA, USA
| | - John A Detre
- Laboratory for Structural Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Perelman School of Medicine, PA, USA
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Pei-Hsin Wu
- Laboratory for Structural Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Perelman School of Medicine, PA, USA
| | - Felix W Wehrli
- Laboratory for Structural Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Perelman School of Medicine, PA, USA
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19
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Byun JI, Cha KS, Jun JE, Kim TJ, Jung KY, Jeong IK, Shin WC. Dynamic changes in nocturnal blood glucose levels are associated with sleep-related features in patients with obstructive sleep apnea. Sci Rep 2020; 10:17877. [PMID: 33087786 PMCID: PMC7578637 DOI: 10.1038/s41598-020-74908-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022] Open
Abstract
Obstructive sleep apnea (OSA) has a bidirectional relationship with insulin resistance conditions; however, the mechanism remains unclear. This study aimed to compare dynamic nocturnal glucose changes among patients with OSA of varying levels of severity and evaluate temporal changes associated with the cardinal features of OSA (sympathetic hyperactivation, intermittent hypoxemia, and sleep fragmentation) in nondiabetic subjects. Nocturnal glucose was measured with a continuous glucose monitoring device every 5 min during polysomnography (PSG). The OSA features were evaluated using heart rate variability (HRV), minimum saturation, and electroencephalography. Eleven subjects with moderate to severe OSA and 12 subjects with no or mild OSA were evaluated. Those with moderate to severe OSA showed an increasing trend in blood glucose levels after sleep onset, whereas those without or with mild OSA showed a decreasing trend (F = 8.933, p < 0.001). Delta band power also showed different trends during sleep between the two groups (F = 2.991, p = 0.009), and minimum saturation remained lower in the moderate to severe OSA group than in the no or mild OSA group. High degrees of coupling between nocturnal glucose levels and each OSA feature were observed. Altered trends in nocturnal glucose in moderate to severe OSA may reflect glucose intolerance and result in metabolic consequences. Managing the features of sleep-related OSA may have implications for metabolic management in the future.
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Affiliation(s)
- Jung-Ick Byun
- Department of Neurology, Kyung Hee University School of Medicine, Kyung Hee University Hospital At Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, 134-727, Republic of South Korea
| | - Kwang Su Cha
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of South Korea
| | - Ji Eun Jun
- Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Kyung Hee University Hospital At Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, 134-727, Republic of South Korea
| | - Tae-Joon Kim
- Department of Neurology, Ajou University School of Medicine, Suwon, Republic of South Korea
| | - Ki-Young Jung
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of South Korea
| | - In-Kyung Jeong
- Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Kyung Hee University Hospital At Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, 134-727, Republic of South Korea.
| | - Won Chul Shin
- Department of Neurology, Kyung Hee University School of Medicine, Kyung Hee University Hospital At Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul, 134-727, Republic of South Korea.
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20
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Mansur RB, Lee Y, McIntyre RS, Brietzke E. What is bipolar disorder? A disease model of dysregulated energy expenditure. Neurosci Biobehav Rev 2020; 113:529-545. [PMID: 32305381 DOI: 10.1016/j.neubiorev.2020.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/30/2020] [Accepted: 04/05/2020] [Indexed: 12/24/2022]
Abstract
Advances in the understanding and management of bipolar disorder (BD) have been slow to emerge. Despite notable recent developments in neurosciences, our conceptualization of the nature of this mental disorder has not meaningfully progressed. One of the key reasons for this scenario is the continuing lack of a comprehensive disease model. Within the increasing complexity of modern research methods, there is a clear need for an overarching theoretical framework, in which findings are assimilated and predictions are generated. In this review and hypothesis article, we propose such a framework, one in which dysregulated energy expenditure is a primary, sufficient cause for BD. Our proposed model is centered on the disruption of the molecular and cellular network regulating energy production and expenditure, as well its potential secondary adaptations and compensatory mechanisms. We also focus on the putative longitudinal progression of this pathological process, considering its most likely periods for onset, such as critical periods that challenges energy homeostasis (e.g. neurodevelopment, social isolation), and the resulting short and long-term phenotypical manifestations.
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Affiliation(s)
- Rodrigo B Mansur
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| | - Yena Lee
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Roger S McIntyre
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Elisa Brietzke
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada; Kingston General Hospital, Providence Care Hospital, Department of Psychiatry, Queen's University School of Medicine, Kingston, ON, Canada
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21
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Chen JE, Lewis LD, Chang C, Tian Q, Fultz NE, Ohringer NA, Rosen BR, Polimeni JR. Resting-state "physiological networks". Neuroimage 2020; 213:116707. [PMID: 32145437 DOI: 10.1016/j.neuroimage.2020.116707] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 02/26/2020] [Accepted: 03/03/2020] [Indexed: 12/21/2022] Open
Abstract
Slow changes in systemic brain physiology can elicit large fluctuations in fMRI time series, which manifest as structured spatial patterns of temporal correlations between distant brain regions. Here, we investigated whether such "physiological networks"-sets of segregated brain regions that exhibit similar responses following slow changes in systemic physiology-resemble patterns associated with large-scale networks typically attributed to remotely synchronized neuronal activity. By analyzing a large group of subjects from the 3T Human Connectome Project (HCP) database, we demonstrate brain-wide and noticeably heterogenous dynamics tightly coupled to either respiratory variation or heart rate changes. We show, using synthesized data generated from physiological recordings across subjects, that these physiologically-coupled fluctuations alone can produce networks that strongly resemble previously reported resting-state networks, suggesting that, in some cases, the "physiological networks" seem to mimic the neuronal networks. Further, we show that such physiologically-relevant connectivity estimates appear to dominate the overall connectivity observations in multiple HCP subjects, and that this apparent "physiological connectivity" cannot be removed by the use of a single nuisance regressor for the entire brain (such as global signal regression) due to the clear regional heterogeneity of the physiologically-coupled responses. Our results challenge previous notions that physiological confounds are either localized to large veins or globally coherent across the cortex, therefore emphasizing the necessity to consider potential physiological contributions in fMRI-based functional connectivity studies. The rich spatiotemporal patterns carried by such "physiological" dynamics also suggest great potential for clinical biomarkers that are complementary to large-scale neuronal networks.
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Affiliation(s)
- Jingyuan E Chen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA.
| | - Laura D Lewis
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Catie Chang
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, USA
| | - Qiyuan Tian
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Nina E Fultz
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Ned A Ohringer
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Bruce R Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA; Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Cambridge, MA, USA
| | - Jonathan R Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA; Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Cambridge, MA, USA
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22
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Regan MD, Flynn-Evans EE, Griko YV, Kilduff TS, Rittenberger JC, Ruskin KJ, Buck CL. Shallow metabolic depression and human spaceflight: a feasible first step. J Appl Physiol (1985) 2020; 128:637-647. [PMID: 31999524 DOI: 10.1152/japplphysiol.00725.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Synthetic torpor is an induced state of deep metabolic depression (MD) in an organism that does not naturally employ regulated and reversible MD. If applied to spaceflight crewmembers, this metabolic state may theoretically mitigate numerous biological and logistical challenges of human spaceflight. These benefits have been the focus of numerous recent articles where, invariably, they are discussed in the context of hypothetical deep MD states in which the metabolism of crewmembers is profoundly depressed relative to basal rates. However, inducing these deep MD states in humans, particularly humans aboard spacecraft, is currently impossible. Here, we discuss shallow MD as a feasible first step toward synthetic torpor during spaceflight and summarize perspectives following a recent NASA-hosted workshop. We discuss methods to safely induce shallow MD (e.g., sleep and slow wave enhancement via acoustic and photoperiod stimulation; moderate sedation via dexmedetomidine), which we define as an ~20% depression of metabolic rate relative to basal levels. We also discuss different modes of shallow MD application (e.g., habitual versus targeted, whereby shallow MD is induced routinely throughout a mission or only under certain circumstances, respectively) and different spaceflight scenarios that would benefit from its use. Finally, we propose a multistep development plan toward the application of synthetic torpor to human spaceflight, highlighting shallow MD's role. As space agencies develop missions to send humans further into space than ever before, shallow MD has the potential to confer health benefits for crewmembers, reduce demands on spacecraft capacities, and serve as a testbed for deeper MD technologies.
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Affiliation(s)
- Matthew D Regan
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Erin E Flynn-Evans
- Fatigue Countermeasures Laboratory, Human Systems Integration Division, NASA Ames Research Center, Moffett Field, California
| | - Yuri V Griko
- Countermeasure Development Laboratory, Space Biosciences Division, NASA Ames Research Center, Moffett Field, California
| | - Thomas S Kilduff
- Biosciences Division, Center for Neuroscience, SRI International, Menlo Park, California
| | - Jon C Rittenberger
- Guthrie Robert Packer Hospital Emergency Medicine Program, Geisinger Commonwealth School of Medicine, Scranton, Pennsylvania
| | - Keith J Ruskin
- Department of Anesthesia and Critical Care, University of Chicago, Chicago, Illinois
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
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23
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Warner SO, Yao MV, Cason RL, Winnick JJ. Exercise-Induced Improvements to Whole Body Glucose Metabolism in Type 2 Diabetes: The Essential Role of the Liver. Front Endocrinol (Lausanne) 2020; 11:567. [PMID: 32982968 PMCID: PMC7484211 DOI: 10.3389/fendo.2020.00567] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/13/2020] [Indexed: 01/22/2023] Open
Abstract
Type 2 diabetes (T2D) is a metabolic disease characterized by obesity, insulin resistance, and the dysfunction of several key glucoregulatory organs. Among these organs, impaired liver function is recognized as one of the earliest contributors to impaired whole-body glucose homeostasis, with well-characterized hepatic insulin resistance resulting in elevated rates of hepatic glucose production (HGP) and fasting hyperglycemia. One portion of this review will provide an overview of how HGP is regulated during the fasted state in healthy humans and how this process becomes dysregulated in patients with T2D. Less well-appreciated is the liver's role in post-prandial glucose metabolism, where it takes up and metabolizes one-third of orally ingested glucose. An abundance of literature has shown that the process of hepatic glucose uptake is impaired in patients with T2D, thereby contributing to glucose intolerance. A second portion of this review will outline how hepatic glucose uptake is regulated during the post-prandial state, and how it becomes dysfunctional in patients with T2D. Finally, it is well-known that exercise training has an insulin-sensitizing effect on the liver, which contributes to improved whole-body glucose metabolism in patients with T2D, thereby making it a cornerstone in the management of the disease. To this end, the impact of exercise on hepatic glucose metabolism will be thoroughly discussed, referencing key findings in the literature. At the same time, sources of heterogeneity that contribute to inconsistent findings in the field will be pointed out, as will important topics for future investigation.
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Affiliation(s)
- Shana O. Warner
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Michael V. Yao
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Rebecca L. Cason
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Jason J. Winnick
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- *Correspondence: Jason J. Winnick
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24
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McAvoy MP, Tagliazucchi E, Laufs H, Raichle ME. Human non-REM sleep and the mean global BOLD signal. J Cereb Blood Flow Metab 2019; 39:2210-2222. [PMID: 30073858 PMCID: PMC6827126 DOI: 10.1177/0271678x18791070] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 06/27/2018] [Indexed: 12/28/2022]
Abstract
A hallmark of non-rapid eye movement (REM) sleep is the decreased brain activity as measured by global reductions in cerebral blood flow, oxygen metabolism, and glucose metabolism. It is unknown whether the blood oxygen level dependent (BOLD) signal undergoes similar changes. Here we show that, in contrast to the decreases in blood flow and metabolism, the mean global BOLD signal increases with sleep depth in a regionally non-uniform manner throughout gray matter. We relate our findings to the circulatory and metabolic processes influencing the BOLD signal and conclude that because oxygen consumption decreases proportionately more than blood flow in sleep, the resulting decrease in paramagnetic deoxyhemoglobin accounts for the increase in mean global BOLD signal.
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Affiliation(s)
- Mark P McAvoy
- Department of Radiology, Washington University, Saint Louis, MO, USA
| | - Enzo Tagliazucchi
- PICNIC Lab, Institut du Cerveau et de la Moelle épinière, Paris, France
| | - Helmut Laufs
- Department of Neurology, Brain Imaging Center, Goethe-Universität Frankfurt am Main, Frankfurt, Germany
- Department of Neurology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Marcus E Raichle
- Department of Radiology, Washington University, Saint Louis, MO, USA
- Alan and Edith L. Wolff Distinguished Professor of Medicine, Washington University, Saint Louis, MO, USA
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25
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Blazey T, Snyder AZ, Su Y, Goyal MS, Lee JJ, Vlassenko AG, Arbeláez AM, Raichle ME. Quantitative positron emission tomography reveals regional differences in aerobic glycolysis within the human brain. J Cereb Blood Flow Metab 2019; 39:2096-2102. [PMID: 29569986 PMCID: PMC6775584 DOI: 10.1177/0271678x18767005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Glucose and oxygen metabolism are tightly coupled in the human brain, with the preponderance of the brain's glucose supply used to generate ATP via oxidative phosphorylation. A fraction of glucose is consumed outside of oxidative phosphorylation despite the presence of sufficient oxygen to do so. We refer to this process as aerobic glycolysis. A recent positron emission tomography study reported that aerobic glycolysis is uniform within gray matter. Here, we analyze the same data and demonstrate robust regional differences in aerobic glycolysis within gray matter, a finding consistent with previously published data.
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Affiliation(s)
- Tyler Blazey
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO, USA
| | - Abraham Z Snyder
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO, USA.,Department of Neurology, School of Medicine, Washington University, St. Louis, MO, USA
| | - Yi Su
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO, USA
| | - Manu S Goyal
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO, USA.,Department of Neurology, School of Medicine, Washington University, St. Louis, MO, USA
| | - John J Lee
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO, USA
| | - Andrei G Vlassenko
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO, USA
| | - Ana Maria Arbeláez
- Department of Pediatrics, School of Medicine, Washington University, St. Louis, MO, USA
| | - Marcus E Raichle
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO, USA.,Department of Neurology, School of Medicine, Washington University, St. Louis, MO, USA.,Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
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26
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Byczkowicz N, Eshra A, Montanaro J, Trevisiol A, Hirrlinger J, Kole MH, Shigemoto R, Hallermann S. HCN channel-mediated neuromodulation can control action potential velocity and fidelity in central axons. eLife 2019; 8:42766. [PMID: 31496517 PMCID: PMC6733576 DOI: 10.7554/elife.42766] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 08/13/2019] [Indexed: 12/31/2022] Open
Abstract
Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels control electrical rhythmicity and excitability in the heart and brain, but the function of HCN channels at the subcellular level in axons remains poorly understood. Here, we show that the action potential conduction velocity in both myelinated and unmyelinated central axons can be bidirectionally modulated by a HCN channel blocker, cyclic adenosine monophosphate (cAMP), and neuromodulators. Recordings from mouse cerebellar mossy fiber boutons show that HCN channels ensure reliable high-frequency firing and are strongly modulated by cAMP (EC50 40 µM; estimated endogenous cAMP concentration 13 µM). In addition, immunogold-electron microscopy revealed HCN2 as the dominating subunit in cerebellar mossy fibers. Computational modeling indicated that HCN2 channels control conduction velocity primarily by altering the resting membrane potential and are associated with significant metabolic costs. These results suggest that the cAMP-HCN pathway provides neuromodulators with an opportunity to finely tune energy consumption and temporal delays across axons in the brain.
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Affiliation(s)
- Niklas Byczkowicz
- Carl-Ludwig-Institute for Physiology, Medical Faculty, University Leipzig, Leipzig, Germany
| | - Abdelmoneim Eshra
- Carl-Ludwig-Institute for Physiology, Medical Faculty, University Leipzig, Leipzig, Germany
| | - Jacqueline Montanaro
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Andrea Trevisiol
- Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Medical Faculty, University Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Maarten Hp Kole
- Department of Axonal Signaling, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, Netherlands.,Cell Biology, Faculty of Science, University of Utrecht, Padualaan, Netherlands
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Stefan Hallermann
- Carl-Ludwig-Institute for Physiology, Medical Faculty, University Leipzig, Leipzig, Germany
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27
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Aerobic Glycolysis Is Required for Spatial Memory Acquisition But Not Memory Retrieval in Mice. eNeuro 2019; 6:eN-NWR-0389-18. [PMID: 30809587 PMCID: PMC6390195 DOI: 10.1523/eneuro.0389-18.2019] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/23/2019] [Accepted: 01/26/2019] [Indexed: 12/18/2022] Open
Abstract
The consolidation of newly formed memories and their retrieval are energetically demanding processes. Aerobic glycolysis (AG), also known as the Warburg effect, consists of the production of lactate from glucose in the presence of oxygen. The astrocyte neuron lactate shuttle hypothesis posits that astrocytes process glucose by AG to generate lactate, which is used as a fuel source within neurons to maintain synaptic activity. Studies in mice have demonstrated that lactate transport between astrocytes and neurons is required for long-term memory formation, yet the role of lactate production in memory acquisition and retrieval has not previously been explored. Here, we examined the effect of dichloroacetate (DCA), a chemical inhibitor of lactate production, on spatial learning and memory in mice using the Morris water maze (MWM). In vivo hyperpolarized 13C-pyruvate magnetic resonance spectroscopy revealed decreased conversion of pyruvate to lactate in the mouse brain following DCA administration, concomitant with a reduction in the phosphorylation of pyruvate dehydrogenase. DCA exposure before each training session in the MWM impaired learning, which subsequently resulted in impaired memory during the probe trial. In contrast, mice that underwent training without DCA exposure, but received a single DCA injection before the probe trial exhibited normal memory. Our findings indicate that AG plays a key role during memory acquisition but is less important for the retrieval of established memories. Thus, the activation of AG may be important for learning-dependent synaptic plasticity rather than the activation of signaling cascades required for memory retrieval.
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28
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Abstract
Glucose is the long-established, obligatory fuel for brain that fulfills many critical functions, including ATP production, oxidative stress management, and synthesis of neurotransmitters, neuromodulators, and structural components. Neuronal glucose oxidation exceeds that in astrocytes, but both rates increase in direct proportion to excitatory neurotransmission; signaling and metabolism are closely coupled at the local level. Exact details of neuron-astrocyte glutamate-glutamine cycling remain to be established, and the specific roles of glucose and lactate in the cellular energetics of these processes are debated. Glycolysis is preferentially upregulated during brain activation even though oxygen availability is sufficient (aerobic glycolysis). Three major pathways, glycolysis, pentose phosphate shunt, and glycogen turnover, contribute to utilization of glucose in excess of oxygen, and adrenergic regulation of aerobic glycolysis draws attention to astrocytic metabolism, particularly glycogen turnover, which has a high impact on the oxygen-carbohydrate mismatch. Aerobic glycolysis is proposed to be predominant in young children and specific brain regions, but re-evaluation of data is necessary. Shuttling of glucose- and glycogen-derived lactate from astrocytes to neurons during activation, neurotransmission, and memory consolidation are controversial topics for which alternative mechanisms are proposed. Nutritional therapy and vagus nerve stimulation are translational bridges from metabolism to clinical treatment of diverse brain disorders.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences , Little Rock, Arkansas ; and Department of Cell Biology and Physiology, University of New Mexico , Albuquerque, New Mexico
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29
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Elvsåshagen T, Mutsaerts HJ, Zak N, Norbom LB, Quraishi SH, Pedersen PØ, Malt UF, Westlye LT, van Someren EJ, Bjørnerud A, Groote IR. Cerebral blood flow changes after a day of wake, sleep, and sleep deprivation. Neuroimage 2018; 186:497-509. [PMID: 30471387 DOI: 10.1016/j.neuroimage.2018.11.032] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 11/01/2018] [Accepted: 11/20/2018] [Indexed: 10/27/2022] Open
Abstract
Elucidating the neurobiological effects of sleep and wake is an important goal of the neurosciences. Whether and how human cerebral blood flow (CBF) changes during the sleep-wake cycle remain to be clarified. Based on the synaptic homeostasis hypothesis of sleep and wake, we hypothesized that a day of wake and a night of sleep deprivation would be associated with gray matter resting CBF (rCBF) increases and that sleep would be associated with rCBF decreases. Thirty-eight healthy adult males (age 22.1 ± 2.5 years) underwent arterial spin labeling perfusion magnetic resonance imaging at three time points: in the morning after a regular night's sleep, the evening of the same day, and the next morning, either after total sleep deprivation (n = 19) or a night of sleep (n = 19). All analyses were adjusted for hematocrit and head motion. rCBF increased from morning to evening and decreased after a night of sleep. These effects were most prominent in bilateral hippocampus, amygdala, thalamus, and in the occipital and sensorimotor cortices. Group × time interaction analyses for evening versus next morning revealed significant interaction in bilateral lateral and medial occipital cortices and in bilateral insula, driven by rCBF increases in the sleep deprived individuals and decreases in the sleepers, respectively. Furthermore, group × time interaction analyses for first morning versus next morning showed significant effects in medial and lateral occipital cortices, in anterior cingulate gyrus, and in the insula, in both hemispheres. These effects were mainly driven by CBF increases from TP1 to TP3 in the sleep deprived individuals. There were no associations between the rCBF changes and sleep characteristics, vigilant attention, or subjective sleepiness that remained significant after adjustments for multiple analyses. Altogether, these results encourage future studies to clarify mechanisms underlying sleep-related rCBF changes.
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Affiliation(s)
- Torbjørn Elvsåshagen
- Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Oslo University Hospital, Norway; Department of Neurology, Oslo University Hospital, Norway; Institute of Clinical Medicine, University of Oslo, Norway.
| | - Henri Jmm Mutsaerts
- Cognitive Neurology Research Unit, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiology, Amsterdam University Medical Center, the Netherlands
| | - Nathalia Zak
- Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Oslo University Hospital, Norway
| | - Linn B Norbom
- Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Oslo University Hospital, Norway
| | | | - Per Ø Pedersen
- Institute of Clinical Medicine, University of Oslo, Norway
| | - Ulrik F Malt
- Institute of Clinical Medicine, University of Oslo, Norway; Department of Research and Education, Oslo University Hospital, Norway
| | - Lars T Westlye
- Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Oslo University Hospital, Norway; Department of Psychology, University of Oslo, Norway
| | - Eus Jw van Someren
- Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands; Department of Psychiatry, Amsterdam University Medical Center, the Netherlands; Department of Integrative Neurophysiology, Amsterdam University Medical Center, the Netherlands
| | - Atle Bjørnerud
- Department of Psychology, University of Oslo, Norway; Department of Physics, University of Oslo, Norway; The Intervention Center, Oslo University Hospital, Norway
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30
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Abstract
Appraising success in meeting the world's nutritional needs has largely focused on infant mortality and anthropometric measurements with an emphasis on the first 1,000 days (conception to approximately age 2 years). This ignores the unique nutritional needs of the human brain. Although the intrauterine environment and the early postnatal years are important, equally critical periods follow during which the brain's intricate wiring is established for a lifetime of experience-driven remodeling. At the peak of this process during childhood, the human brain may account for 50% of the body's basal nutritional requirement. Thus, the consequences of proper nutritional management of the brain play out over a lifetime. Our motivation in preparing this review was to move the human brain into a more central position in the planning of nutritional programs. Here we review the macro- and micronutrient requirements of the human brain and how they are delivered, from conception to adulthood.
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Affiliation(s)
- Manu S. Goyal
- Mallinckrodt Institute of Radiology and Department of Neurology, Washington University School of Medicine, Washington University, St. Louis, Missouri 63130, USA
| | - Lora L. Iannotti
- Brown School, Institute for Public Health, Washington University, St. Louis, Missouri 63130, USA
| | - Marcus E. Raichle
- Mallinckrodt Institute of Radiology and Department of Neurology, Washington University School of Medicine, Washington University, St. Louis, Missouri 63130, USA
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31
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Abstract
PURPOSE OF REVIEW The goal of the present paper is to review current literature supporting the occurrence of fundamental changes in brain energy metabolism during the transition from wakefulness to sleep. RECENT FINDINGS Latest research in the field indicates that glucose utilization and the concentrations of several brain metabolites consistently change across the sleep-wake cycle. Lactate, a product of glycolysis that is involved in synaptic plasticity, has emerged as a good biomarker of brain state. Sleep-induced changes in cerebral metabolite levels result from a shift in oxidative metabolism, which alters the reliance of brain metabolism upon carbohydrates. We found wide support for the notion that brain energetics is state dependent. In particular, fatty acids and ketone bodies partly replace glucose as cerebral energy source during sleep. This mechanism plausibly accounts for increases in biosynthetic pathways and functional alterations in neuronal activity associated with sleep. A better account of brain energy metabolism during sleep might help elucidate the long mysterious restorative effects of sleep for the whole organism.
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Affiliation(s)
- Nadia Nielsen Aalling
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Allé 14, 2200, Copenhagen N, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Allé 14, 2200, Copenhagen N, Denmark.,Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY, 14640, USA
| | - Mauro DiNuzzo
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Allé 14, 2200, Copenhagen N, Denmark.
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32
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Henriksen OM, Vestergaard MB, Lindberg U, Aachmann-Andersen NJ, Lisbjerg K, Christensen SJ, Rasmussen P, Olsen NV, Forman JL, Larsson HBW, Law I. Interindividual and regional relationship between cerebral blood flow and glucose metabolism in the resting brain. J Appl Physiol (1985) 2018; 125:1080-1089. [PMID: 29975605 DOI: 10.1152/japplphysiol.00276.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Studies of the resting brain measurements of cerebral blood flow (CBF) show large interindividual and regional variability, but the metabolic basis of this variability is not fully established. The aim of the present study was to reassess regional and interindividual relationships between cerebral perfusion and glucose metabolism in the resting brain. Regional quantitative measurements of CBF and cerebral metabolic rate of glucose (CMRglc) were obtained in 24 healthy young men using dynamic [15O]H2O and [18F]fluorodeoxyglucose positron emission tomography (PET). Magnetic resonance imaging measurements of global oxygen extraction fraction (gOEF) and metabolic rate of oxygen ([Formula: see text]) were obtained by combined susceptometry-based sagittal sinus oximetry and phase contrast mapping. No significant interindividual associations between global CBF, global CMRglc, and [Formula: see text] were observed. Linear mixed-model analysis showed a highly significant association of CBF with CMRglc regionally. Compared with neocortex significantly higher CBF values than explained by CMRglc were demonstrated in infratentorial structures, thalami, and mesial temporal cortex, and lower values were found in the striatum and cerebral white matter. The present study shows that absolute quantitative global CBF measurements appear not to be a valid surrogate measure of global cerebral glucose or oxygen consumption, and further demonstrates regionally variable relationship between perfusion and glucose metabolism in the resting brain that could suggest regional differences in energy substrate metabolism. NEW & NOTEWORTHY Using method-independent techniques the study cannot confirm direct interindividual correlations of absolute global values of perfusion with oxygen or glucose metabolism in the resting brain, and absolute global perfusion measurements appear not to be valid surrogate measures of cerebral metabolism. The ratio of both perfusion and oxygen delivery to glucose metabolism varies regionally, also when accounting for known methodological regional bias in quantification of glucose metabolism.
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Affiliation(s)
- Otto M Henriksen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen , Denmark
| | - Mark B Vestergaard
- Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Glostrup, Denmark
| | - Ulrich Lindberg
- Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Glostrup, Denmark
| | | | - Kristian Lisbjerg
- Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet, Copenhagen , Denmark
| | - Søren J Christensen
- Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet, Copenhagen , Denmark
| | - Peter Rasmussen
- Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Niels V Olsen
- Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet, Copenhagen , Denmark.,Department of Neuroscience and Pharmacology, The Faculty of Health Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Julie L Forman
- Section of Biostatistics, University of Copenhagen, The Faculty of Health Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Henrik B W Larsson
- Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Glostrup, Denmark.,Institute of Clinical Medicine, The Faculty of Health Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Ian Law
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen , Denmark.,Institute of Clinical Medicine, The Faculty of Health Sciences, University of Copenhagen , Copenhagen , Denmark
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33
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Goyal MS, Vlassenko AG, Blazey TM, Su Y, Couture LE, Durbin TJ, Bateman RJ, Benzinger TLS, Morris JC, Raichle ME. Loss of Brain Aerobic Glycolysis in Normal Human Aging. Cell Metab 2017; 26:353-360.e3. [PMID: 28768174 PMCID: PMC5573225 DOI: 10.1016/j.cmet.2017.07.010] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 05/25/2017] [Accepted: 07/17/2017] [Indexed: 01/06/2023]
Abstract
The normal aging human brain experiences global decreases in metabolism, but whether this affects the topography of brain metabolism is unknown. Here we describe PET-based measurements of brain glucose uptake, oxygen utilization, and blood flow in cognitively normal adults from 20 to 82 years of age. Age-related decreases in brain glucose uptake exceed that of oxygen use, resulting in loss of brain aerobic glycolysis (AG). Whereas the topographies of total brain glucose uptake, oxygen utilization, and blood flow remain largely stable with age, brain AG topography changes significantly. Brain regions with high AG in young adults show the greatest change, as do regions with prolonged developmental transcriptional features (i.e., neoteny). The normal aging human brain thus undergoes characteristic metabolic changes, largely driven by global loss and topographic changes in brain AG.
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Affiliation(s)
- Manu S Goyal
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA; Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Andrei G Vlassenko
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tyler M Blazey
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yi Su
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lars E Couture
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tony J Durbin
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Randall J Bateman
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA; Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tammie L-S Benzinger
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - John C Morris
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA; Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marcus E Raichle
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
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Inadequate sleep as a contributor to type 2 diabetes in children and adolescents. Nutr Diabetes 2017; 7:e266. [PMID: 28481337 PMCID: PMC5518801 DOI: 10.1038/nutd.2017.19] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/04/2017] [Accepted: 03/20/2017] [Indexed: 12/17/2022] Open
Abstract
Lack of sleep is a modifiable risk factor for adverse health in humans. Short sleep duration and poor sleep quality are common in the pediatric population; the largest decline in sleep duration over the past decades has been seen in children and adolescents. The objective of the present narrative review was to provide for the first time an overview of the literature on sleep and its association with type 2 diabetes mellitus (T2D) biomarkers in children and adolescents. For this narrative review, 23 studies were retained (21 observational and 2 experimental studies). Notwithstanding the conflicting results found in these studies and despite being attenuated by adiposity level, maturity, sex and age, there is still some compelling evidence for an association between sleep duration (for both objective or subjective measurements of duration) and architecture with one or more T2D biomarkers in children and adolescents. The majority of the studies reviewed did focus on sleep duration and one or more T2D biomarkers in children and adolescents, but sleep architecture, more precisely the suppression of slow wave sleep and rapid eye movement sleep, has also been shown to be associated with insulin resistance. Only two studies looked at sleep quality, and the association between sleep quality and insulin resistance was not independent of level of adiposity. Future experimental studies will help to better understand the mechanisms linking insufficient sleep with T2D. Work also needs to be carried out on finding novel and effective strategies aimed at improving sleep hygiene and health outcomes of children and adolescents.
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Jekabsons MB, Gebril HM, Wang YH, Avula B, Khan IA. Updates to a 13C metabolic flux analysis model for evaluating energy metabolism in cultured cerebellar granule neurons from neonatal rats. Neurochem Int 2017; 109:54-67. [PMID: 28412312 DOI: 10.1016/j.neuint.2017.03.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 03/27/2017] [Accepted: 03/30/2017] [Indexed: 10/19/2022]
Abstract
A hexose phosphate recycling model previously developed to infer fluxes through the major glucose consuming pathways in cultured cerebellar granule neurons (CGNs) from neonatal rats metabolizing [1,2-13C2]glucose was revised by considering reverse flux through the non-oxidative pentose phosphate pathway (PPP) and symmetrical succinate oxidation within the tricarboxylic acid (TCA) cycle. The model adjusts three flux ratios to effect 13C distribution in the hexose, pentose, and triose phosphate pools, and in TCA cycle malate to minimize the error between predicted and measured 13C labeling in exported lactate (i.e., unlabeled, single-, double-, and triple-labeled; M, M1, M2, and M3, respectively). Inclusion of reverse non-oxidative PPP flux substantially increased the number of calculations but ultimately had relatively minor effects on the labeling of glycolytic metabolites. From the error-minimized solution in which the predicted M-M3 lactate differed by 0.49% from that measured by liquid chromatography-triple quadrupole mass spectrometry, the neurons exhibited negligible forward non-oxidative PPP flux. Thus, no glucose was used by the pentose cycle despite explicit consideration of hexose phosphate recycling. Mitochondria consumed only 16% of glucose while 45% was exported as lactate by aerobic glycolysis. The remaining 39% of glucose was shunted to pentose phosphates presumably for de novo nucleotide synthesis, but the proportion metabolized through the oxidative PPP vs. the reverse non-oxidative PPP could not be determined. The lactate exported as M1 (2.5%) and M3 (1.2%) was attributed to malic enzyme, which was responsible for 7.8% of pyruvate production (vs. 92.2% by glycolysis). The updated model is more broadly applicable to different cell types by considering bi-directional flux through the non-oxidative PPP. Its application to cultured neurons utilizing glucose as the sole exogenous substrate has demonstrated substantial oxygen-independent glucose utilization by aerobic glycolysis as well as the oxidative PPP and/or reverse non-oxidative PPP, but negligible glucose consumption by the pentose cycle.
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Affiliation(s)
- Mika B Jekabsons
- Department of Biology, 110 Shoemaker Hall, University of Mississippi, University, MS 38677, USA.
| | - Hoda M Gebril
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
| | - Yan-Hong Wang
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
| | - Bharathi Avula
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
| | - Ikhlas A Khan
- Department of Biomedical Sciences and National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
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Su Y, Vlassenko AG, Couture LE, Benzinger TL, Snyder AZ, Derdeyn CP, Raichle ME. Quantitative hemodynamic PET imaging using image-derived arterial input function and a PET/MR hybrid scanner. J Cereb Blood Flow Metab 2017; 37:1435-1446. [PMID: 27401805 PMCID: PMC5453463 DOI: 10.1177/0271678x16656200] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Positron emission tomography (PET) with 15O-tracers is commonly used to measure brain hemodynamic parameters such as cerebral blood flow, cerebral blood volume, and cerebral metabolic rate of oxygen. Conventionally, the absolute quantification of these parameters requires an arterial input function that is obtained invasively by sampling blood from an artery. In this work, we developed and validated an image-derived arterial input function technique that avoids the unreliable and burdensome arterial sampling procedure for full quantitative 15O-PET imaging. We then compared hemodynamic PET imaging performed on a PET/MR hybrid scanner against a conventional PET only scanner. We demonstrated the proposed imaging-based technique was able to generate brain hemodynamic parameter measurements in strong agreement with the traditional arterial sampling based approach. We also demonstrated that quantitative 15O-PET imaging can be successfully implemented on a PET/MR hybrid scanner.
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Affiliation(s)
- Yi Su
- 1 Mallinckrodt Institute of Radiology, Washington University School of Medicine, USA
| | - Andrei G Vlassenko
- 1 Mallinckrodt Institute of Radiology, Washington University School of Medicine, USA
| | - Lars E Couture
- 1 Mallinckrodt Institute of Radiology, Washington University School of Medicine, USA
| | - Tammie Ls Benzinger
- 1 Mallinckrodt Institute of Radiology, Washington University School of Medicine, USA.,2 Department Neurosurgery, Washington University School of Medicine, USA
| | - Abraham Z Snyder
- 1 Mallinckrodt Institute of Radiology, Washington University School of Medicine, USA
| | | | - Marcus E Raichle
- 1 Mallinckrodt Institute of Radiology, Washington University School of Medicine, USA.,4 Department of Neurology, Washington University School of Medicine, USA
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Kayaba M, Park I, Iwayama K, Seya Y, Ogata H, Yajima K, Satoh M, Tokuyama K. Energy metabolism differs between sleep stages and begins to increase prior to awakening. Metabolism 2017; 69:14-23. [PMID: 28285643 DOI: 10.1016/j.metabol.2016.12.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 12/29/2016] [Accepted: 12/29/2016] [Indexed: 11/18/2022]
Abstract
PURPOSE Human sleep is generally consolidated into a single prolonged period, and its metabolic consequence is to impose an extended period of fasting. Changes in sleep stage and homeostatic sleep drive following sleep onset may affect sleeping metabolic rate through cross talk between the mechanisms controlling energy metabolism and sleep. The purpose of this study was to isolate the effects of sleep stage and time after sleep onset on sleeping metabolic rate. METHODS The sleeping metabolic rate of 29 healthy adults was measured using whole room indirect calorimetry, during which polysomnographic recording of sleep was performed. The effects of sleep stage and time after sleep onset on sleeping metabolic rate were evaluated using a semi-parametric regression analysis. A parametric analysis was used for the effect of sleep stage and a non-parametric analysis was used for the effect of time. RESULTS Energy expenditure differed significantly between sleep stages: wake after sleep onset (WASO)>stage 2, slow wave sleep (SWS), and REM; stage 1>stage 2 and SWS; and REM>SWS. Similarly, carbohydrate oxidation differed significantly between sleep stages: WASO > stage 2 and SWS; and stage 1>SWS. Energy expenditure and carbohydrate oxidation decreased during the first half of sleep followed by an increase during the second half of sleep. CONCLUSIONS This study identified characteristic phenotypes in energy expenditure and carbohydrate oxidation indicating that sleeping metabolic rate differs between sleep stages.
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Affiliation(s)
- Momoko Kayaba
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8575, Ibaraki, Japan
| | - Insung Park
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan
| | - Kaito Iwayama
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sports Science, Japan Institute of Sports Sciences, Kita, 115-0056, Tokyo, Japan
| | - Yumi Seya
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8575, Ibaraki, Japan
| | - Hitomi Ogata
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan
| | - Katsuhiko Yajima
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan; Department of Administrative Nutrition, Faculty of Health and Nutrition, Tokyo Seiei College, Katsushika, 124-8530, Tokyo, Japan
| | - Makoto Satoh
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8575, Ibaraki, Japan
| | - Kumpei Tokuyama
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8575, Ibaraki, Japan; Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai1-1-1, Tsukuba, 305-8574, Ibaraki, Japan.
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Mehta R, Singh A, Mallick BN. Disciplined sleep for healthy living: Role of noradrenaline. World J Neurol 2017; 7:6-23. [DOI: 10.5316/wjn.v7.i1.6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/10/2016] [Accepted: 11/29/2016] [Indexed: 02/06/2023] Open
Abstract
Sleep is essential for maintaining normal physiological processes. It has been broadly divided into rapid eye movement sleep (REMS) and non-REMS (NREMS); one spends the least amount of time in REMS. Sleep (both NREMS and REMS) disturbance is associated with most altered states, disorders and pathological conditions. It is affected by factors within the body as well as the environment, which ultimately modulate lifestyle. Noradrenaline (NA) is one of the key molecules whose level increases upon sleep-loss, REMS-loss in particular and it induces several REMS-loss associated effects and symptoms. The locus coeruleus (LC)-NAergic neurons are primarily responsible for providing NA throughout the brain. As those neurons project to and receive inputs from across the brain, they are modulated by lifestyle changes, which include changes within the body as well as in the environment. We have reviewed the literature showing how various inputs from outside and within the body integrate at the LC neuronal level to modulate sleep (NREMS and REMS) and vice versa. We propose that these changes modulate NA levels in the brain, which in turn is responsible for acute as well as chronic psycho-somatic disorders and pathological conditions.
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39
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Mapping visual dominance in human sleep. Neuroimage 2017; 150:250-261. [PMID: 28232191 DOI: 10.1016/j.neuroimage.2017.02.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/15/2017] [Accepted: 02/19/2017] [Indexed: 12/19/2022] Open
Abstract
Sleep is a universal behavior, essential for humans and animals alike to survive. Its importance to a person's physical and mental health cannot be overstated. Although lateralization of function is well established in the lesion, split-brain and task based neuroimaging literature, and more recently in functional imaging studies of spontaneous fluctuations of the fMRI BOLD signal during wakeful rest, it is unknown if these asymmetries are present during sleep. We investigated hemispheric asymmetries in the global brain signal during non-REM sleep. Here we show that increasing sleep depth is accompanied by an increasing rightward asymmetry of regions in visual cortex including primary bilaterally and in the right hemisphere along the lingual gyrus and middle temporal cortex. In addition, left hemisphere language regions largely maintained their leftward asymmetry during sleep. Right hemisphere attention related regions expressed a more complicated relation with some regions maintaining a rightward asymmetry while this was lost in others. These results suggest that asymmetries in the human brain are state dependent.
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40
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Bhushan B, Ayub B, Thompson DM, Abdullah F, Billings KR. Impact of short sleep on metabolic variables in obese children with obstructive sleep apnea. Laryngoscope 2016; 127:2176-2181. [PMID: 27868206 DOI: 10.1002/lary.26420] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/14/2016] [Accepted: 10/13/2016] [Indexed: 11/11/2022]
Abstract
OBJECTIVES/HYPOTHESIS To analyze the association between sleep duration, metabolic variables, and insulin resistance in obese children with and without obstructive sleep apnea. The decline in sleep duration has paralleled a dramatic increase in the prevalence of obesity and diabetes, suggesting a mechanistic relationship. STUDY DESIGN Retrospective, case series. METHODS Consecutive obese patients 3 to 12 years of age who underwent polysomnography (PSG) and a metabolic panel and who completed a 14-item sleep questionnaire were analyzed. All laboratory testing was conducted within 3 months of PSG. Total sleep times were obtained from the PSG and confirmed by the questionnaire. RESULTS A total of 171 patients (55.0% male) were studied. All patients were obese (body mass index [BMI] z score > 95th percentile). Patients were categorized into three groups: short sleepers, borderline sleepers, and optimal sleepers. Eighty-six (50.3%) patients were short sleepers, 71 (41.5%) were borderline sleepers, and 14 (8.2%) were optimal sleepers. The mean BMI z score was 3.13 ± 1.3 in short sleepers, 3.3 ± 1.1 in borderline sleepers, and 3.5 ± 1.5 in optimal sleepers (P = .39). There was no statistical difference in high- and low-density lipoprotein levels (P = .21 and P = .76, respectively) and total cholesterol (P = .43) among subgroups. Triglycerides, blood glucose, insulin, and homeostasis model assessment-insulin resistance were significantly higher in short sleepers when compared to borderline or normal sleepers (P = .008, P < .001, P < .001, and P < .001, respectively). CONCLUSIONS Short sleep duration was correlated with alterations in metabolic variables and insulin resistance in obese patients. This raises concern for development of comorbid conditions that can persist into adulthood. LEVEL OF EVIDENCE 4 Laryngoscope, 127:2176-2181, 2017.
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Affiliation(s)
- Bharat Bhushan
- Division of Otolaryngology-Head and Neck Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago.,Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine
| | - Bushra Ayub
- Division of Otolaryngology-Head and Neck Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago
| | - Dana M Thompson
- Division of Otolaryngology-Head and Neck Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago.,Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine
| | - Fizan Abdullah
- Division of Pediatric Surgery, Department of Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago.,Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois, U.S.A
| | - Kathleen R Billings
- Division of Otolaryngology-Head and Neck Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago.,Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine
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41
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Sharma VK, Sharma P, Deshmukh R, Singh R. Age Associated Sleep Loss: A Trigger For Alzheimer's Disease. ACTA ACUST UNITED AC 2016. [DOI: 10.5455/bcp.20140909070449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Vivek Kumar Sharma
- Government College of Pharmacy, Department of Pharmacology, Rohru, Distt Shimla, Himachal Pradesh-171207, India
| | | | | | - Ranjit Singh
- Government College of Pharmacy, Department of Pharmacology, Rohru, Distt Shimla, Himachal Pradesh-171207, India
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Abstract
In this article, the effect of sleep and sleep disorders on endocrine function and the influence of endocrine abnormalities on sleep are discussed. Sleep disruption and its associated endocrine consequences in the critically ill patient are also reviewed.
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Affiliation(s)
- Dionne Morgan
- Department of Medicine, National Jewish Health, 1400 Jackson Street, A02, Denver, CO 80206, USA
| | - Sheila C Tsai
- Department of Medicine, National Jewish Health, 1400 Jackson Street, A02, Denver, CO 80206, USA; University of Colorado Denver, Aurora, CO 80045, USA.
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43
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EEG power and glucose fluctuations are coupled during sleep in young adults with type 1 diabetes. Clin Neurophysiol 2016; 127:2739-2746. [PMID: 27417046 DOI: 10.1016/j.clinph.2016.05.357] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/25/2016] [Accepted: 05/27/2016] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To determine the coupling between brain activity and glucose variations during sleep in young adults with type 1 diabetes mellitus (T1DM). METHODS 27 participants, age 18-30, wore a continuous glucose monitoring system (CGMS) and underwent in-laboratory overnight polysomnography (PSG). Quantitative electroencephalogram (qEEG) metrics were determined from the PSG and included Delta, Theta, Alpha, Sigma, Beta and Gamma Band power at 5-min intervals. Wavelet Coherence Analysis was employed to determine the time varying and frequency specific coupling between glucose and EEG Band power. ANOVA was used to compare differences across fluctuation speeds and EEG bands. RESULTS There was a high degree of time varying and frequency specific coupling between glucose variations and EEG power in all EEG Bands during sleep. The average number of intervals of statistically significant coherence was highest for fluctuations periods between 10 and 30min in all Bands (p<0.0001 for each). Mean significant coherence was negatively correlated with hemoglobin A1c, a marker of glycemic control. CONCLUSIONS The relationship between glucose and EEG power during sleep is time varying and frequency dependent in young adults with T1DM. SIGNIFICANCE Understanding the time varying mutual relationship between glucose changes and brain activity during sleep may have implications for disease management in T1DM.
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Abstract
Ten percent to 15% of glucose used by the brain is metabolized nonoxidatively despite adequate tissue oxygenation, a process termed aerobic glycolysis (AG). Because of the known role of glycolysis in biosynthesis, we tested whether learning-induced synaptic plasticity would lead to regionally appropriate, learning-dependent changes in AG. Functional MRI (fMRI) before, during, and after performance of a visual-motor adaptation task demonstrated that left Brodmann area 44 (BA44) played a key role in adaptation, with learning-related changes to activity during the task and altered resting-state, functional connectivity after the task. PET scans before and after task performance indicated a sustained increase in AG in left BA 44 accompanied by decreased oxygen consumption. Intersubject variability in behavioral adaptation rate correlated strongly with changes in AG in this region, as well as functional connectivity, which is consistent with a role for AG in synaptic plasticity.
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45
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Feeding the brain and nurturing the mind: Linking nutrition and the gut microbiota to brain development. Proc Natl Acad Sci U S A 2016; 112:14105-12. [PMID: 26578751 DOI: 10.1073/pnas.1511465112] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The human gut contains a microbial community composed of tens of trillions of organisms that normally assemble during the first 2-3 y of postnatal life. We propose that brain development needs to be viewed in the context of the developmental biology of this "microbial organ" and its capacity to metabolize the various diets we consume. We hypothesize that the persistent cognitive abnormalities seen in children with undernutrition are related in part to their persistent gut microbiota immaturity and that specific regions of the brain that normally exhibit persistent juvenile (neotenous) patterns of gene expression, including those critically involved in various higher cognitive functions such as the brain's default mode network, may be particularly vulnerable to the effects of microbiota immaturity in undernourished children. Furthermore, we postulate that understanding the interrelationships between microbiota and brain metabolism in childhood undernutrition could provide insights about responses to injury seen in adults. We discuss approaches that can be used to test these hypotheses, their ramifications for optimizing nutritional recommendations that promote healthy brain development and function, and the potential societal implications of this area of investigation.
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46
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Abstract
In this article, the effect of sleep and sleep disorders on endocrine function and the influence of endocrine abnormalities on sleep are discussed. Sleep disruption and its associated endocrine consequences in the critically ill patient are also reviewed.
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47
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Mitra A, Snyder AZ, Tagliazucchi E, Laufs H, Raichle ME. Propagated infra-slow intrinsic brain activity reorganizes across wake and slow wave sleep. eLife 2015; 4:e10781. [PMID: 26551562 PMCID: PMC4737658 DOI: 10.7554/elife.10781] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/06/2015] [Indexed: 12/14/2022] Open
Abstract
Propagation of slow intrinsic brain activity has been widely observed in electrophysiogical studies of slow wave sleep (SWS). However, in human resting state fMRI (rs-fMRI), intrinsic activity has been understood predominantly in terms of zero-lag temporal synchrony (functional connectivity) within systems known as resting state networks (RSNs). Prior rs-fMRI studies have found that RSNs are generally preserved across wake and sleep. Here, we use a recently developed analysis technique to study propagation of infra-slow intrinsic blood oxygen level dependent (BOLD) signals in normal adults during wake and SWS. This analysis reveals marked changes in propagation patterns in SWS vs. wake. Broadly, ordered propagation is preserved within traditionally defined RSNs but lost between RSNs. Additionally, propagation between cerebral cortex and subcortical structures reverses directions, and intra-cortical propagation becomes reorganized, especially in visual and sensorimotor cortices. These findings show that propagated rs-fMRI activity informs theoretical accounts of the neural functions of sleep.
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Affiliation(s)
- Anish Mitra
- Department of Radiology, Washington University in St. Louis, St. Louis, United States
| | - Abraham Z Snyder
- Department of Radiology, Washington University in St. Louis, St. Louis, United States
- Department of Neurology, Washington University in St. Louis, St. Louis, United States
| | - Enzo Tagliazucchi
- Institute for Medical Psychology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Department of Neurology, Brain Imaging Center, Goethe-Universität Frankfurt am Main, Frankfurt, Germany
| | - Helmut Laufs
- Department of Neurology, Brain Imaging Center, Goethe-Universität Frankfurt am Main, Frankfurt, Germany
- Department of Neurology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Marcus E Raichle
- Department of Radiology, Washington University in St. Louis, St. Louis, United States
- Department of Neurology, Washington University in St. Louis, St. Louis, United States
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Abstract
Mitochondria are called "cellular power plants" because they exclusively contain a respiratory electron transfer chain consisting of five components (complexes I-V) to generate most of the ATP required to maintain cellular functions. Mitochondrial complex I (MC-I) is the first and the largest macrocomplex in the pathway for oxidative phosphorylation. We recently synthesized a series of novel PET probes for quantitative imaging of MC-I activity in the living brain. Several in vitro biological evaluations suggested that (18)F-BCPP-EF could be applicable for MC-I assessment in vivo, and the probe has been applied to several animal disease models of stroke, aging, and dementia. The data suggested that (18)F-BCPP-EF could be useful to detect ischemic neuronal damage at the subacute phase, 7 days, after ischemic insult, at which time unexpectedly higher (18)F-FDG uptake was observed in the damaged area than in the contralateral intact area. Our studies with the aged monkeys demonstrated that (18)F-BCPP-EF detected the age-related reduction of MC-I activity in the living monkey brain, and also that the monkeys with higher amyloid-β deposition showed lower MC-I activity. Since PET is a sophisticated medical modality for noninvasive assessment of real-time tissue function by using target-specific radiolabeled probes, the development of novel PET probes for MC-I should be useful for diagnostic, prognostic, and treatment monitoring of diseases related to impaired MC-I function.
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49
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Inoue Y. Sleep-related eating disorder and its associated conditions. Psychiatry Clin Neurosci 2015; 69:309-20. [PMID: 25495278 DOI: 10.1111/pcn.12263] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/09/2014] [Indexed: 01/22/2023]
Abstract
Sleep-related eating disorder (SRED) is a condition characterized by recurrent episodes of eating at the transition from night-time sleep to arousal. SRED patients describe eating in an out-of-control manner with preference for high-caloric foods and sometimes with inedible or toxic items. Level of consciousness during SRED episodes ranges from partial consciousness to dense unawareness typical of somnambulistic episodes. SRED is sometimes associated with psychotropic medication, in particular sedative hypnotics, and other sleep disorders, including parasomnias, narcolepsy, and restless legs syndrome. Night eating syndrome (NES) is another important condition in the disordered night-time eating spectrum showing hyperphagia episodes at full arousal from nocturnal sleep without accompanying amnesia. NES could be considered an abnormality in the circadian rhythm of meal timing with a normal circadian timing of sleep onset. The two conditions often overlap and possibly share a common pathophysiology. Studies have suggested that central nervous system serotonin modulation may lead to an effective treatment of NES, while the anti-seizure medication topiramate may be an effective SRED treatment.
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Affiliation(s)
- Yuichi Inoue
- Department of Somnology, Tokyo Medical University, Tokyo, Japan.,Neuropsychiatric Research Institute, Tokyo, Japan
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50
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Chandrasekaran S, Rittschof CC, Djukovic D, Gu H, Raftery D, Price ND, Robinson GE. Aggression is associated with aerobic glycolysis in the honey bee brain(1). GENES BRAIN AND BEHAVIOR 2015; 14:158-66. [PMID: 25640316 DOI: 10.1111/gbb.12201] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 01/10/2015] [Accepted: 01/12/2015] [Indexed: 12/22/2022]
Abstract
Aerobic glycolysis involves increased glycolysis and decreased oxidative catabolism of glucose even in the presence of an ample oxygen supply. Aerobic glycolysis, a common metabolic pattern in cancer cells, was recently discovered in both the healthy and diseased human brain, but its functional significance is not understood. This metabolic pattern in the brain is surprising because it results in decreased efficiency of adenosine triphosphate (ATP) production in a tissue with high energetic demands. We report that highly aggressive honey bees (Apis mellifera) show a brain transcriptomic and metabolic state consistent with aerobic glycolysis, i.e. increased glycolysis in combination with decreased oxidative phosphorylation. Furthermore, exposure to alarm pheromone, which provokes aggression, causes a metabolic shift to aerobic glycolysis in the bee brain. We hypothesize that this metabolic state, which is associated with altered neurotransmitter levels, increased glycolytically derived ATP and a reduced cellular redox state, may lead to increased neuronal excitability and oxidative stress in the brain. Our analysis provides evidence for a robust, distinct and persistent brain metabolic response to aggression-inducing social cues. This finding for the first time associates aerobic glycolysis with naturally occurring behavioral plasticity, which has important implications for understanding both healthy and diseased brain function.
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Affiliation(s)
- S Chandrasekaran
- Institute for Systems Biology, Seattle, WA; Center for Biophysics and Computational Biology
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