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Dingwell DA, Cunningham CH. Particle-based MR modeling with diffusion, microstructure, and enzymatic reactions. Magn Reson Med 2024. [PMID: 39250417 DOI: 10.1002/mrm.30279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 07/21/2024] [Accepted: 08/14/2024] [Indexed: 09/11/2024]
Abstract
PURPOSE To develop a novel particle-based in silico MR model and demonstrate applications of this model to signal mechanisms which are affected by the spatial organization of particles, including metabolic reaction kinetics, microstructural effects on diffusion, and radiofrequency (RF) refocusing effects in gradient-echo sequences. METHODS The model was developed by integrating a forward solution of the Bloch equations with a Brownian dynamics simulator. Simulation configurations were then designed to model MR signal dynamics of interest, with a primary focus on hyperpolarized 13C MRI methods. Phantom scans and spectrophotometric assays were conducted to validate model results in vitro. RESULTS The model accurately reproduced the reaction kinetics of enzyme-mediated conversion of pyruvate to lactate. When varying proportions of restrictive structure were added to the reaction volume, nonlinear changes in the reaction rate measured in vitro were replicated in silico. Modeling of RF refocusing effects characterized the degree of diffusion-weighted contribution from preserved residual magnetization in nonspoiled gradient-echo sequences. CONCLUSIONS These results show accurate reproduction of a range of MR signal mechanisms, establishing the model's capability to investigate the multifactorial signal dynamics such as those underlying hyperpolarized 13C MRI data.
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Affiliation(s)
- Dylan Archer Dingwell
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Charles H Cunningham
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
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2
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Zachos KA, Choi J, Godin O, Chernega T, Kwak HA, Jung JH, Aouizerate B, Aubin V, Bellivier F, Belzeaux-R R, Courtet P, Dubertret C, Etain B, Haffen E, Lefrere A A, Llorca PM, Olié E, Polosan M, Samalin L, Schwan R, Roux P, Barau C, Richard JR, Tamouza R, Leboyer M, Andreazza AC. Mitochondrial Biomarkers and Metabolic Syndrome in Bipolar Disorder. Psychiatry Res 2024; 339:116063. [PMID: 39003800 DOI: 10.1016/j.psychres.2024.116063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/16/2024]
Abstract
The object of this study is test whether mitochondrial blood-based biomarkers are associated with markers of metabolic syndrome in bipolar disorder, hypothesizing higher lactate but unchanged cell-free circulating mitochondrial DNA levels in bipolar disorder patients with metabolic syndrome. In a cohort study, primary testing from the FondaMental Advanced Centers of Expertise for bipolar disorder (FACE-BD) was conducted, including 837 stable bipolar disorder patients. The I-GIVE validation cohort consists of 237 participants: stable and acute bipolar patients, non-psychiatric controls, and acute schizophrenia patients. Multivariable regression analyses show significant lactate association with triglycerides, fasting glucose and systolic and diastolic blood pressure. Significantly higher levels of lactate were associated with presence of metabolic syndrome after adjusting for potential confounding factors. Mitochondrial-targeted metabolomics identified distinct metabolite profiles in patients with lactate presence and metabolic syndrome, differing from those without lactate changes but with metabolic syndrome. Circulating cell-free mitochondrial DNA was not associated with metabolic syndrome. This thorough analysis mitochondrial biomarkers indicate the associations with lactate and metabolic syndrome, while showing the mitochondrial metabolites can further stratify metabolic profiles in patients with BD. This study is relevant to improve the identification and stratification of bipolar patients with metabolic syndrome and provide potential personalized-therapeutic opportunities.
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Affiliation(s)
- Kassandra A Zachos
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Mitochondrial Innovation Initiative, MITO2i, Toronto, ON, Canada
| | - Jaehyoung Choi
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Mitochondrial Innovation Initiative, MITO2i, Toronto, ON, Canada
| | - Ophelia Godin
- INSERM U955 IMRB, Translational Neuropsychiatry laboratory, AP-HP, Hôpital Henri Mondor, DMU IMPACT, Fédération Hospitalo-Universitaire de Médecine de Précision en Psychiatrie (FHU ADAPT), Paris Est Créteil University (UPEC), ECNP Immuno-NeuroPsychiatry Network; Fondation FondaMental, Créteil, France
| | - Timofei Chernega
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Haejin Angela Kwak
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Jae H Jung
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Bruno Aouizerate
- Fondation FondaMental, Créteil, France; Centre Hospitalier Charles Perrens, Pôle de Psychiatrie Générale et Universitaire, Laboratoire NutriNeuro (UMR INRAE 1286), Université de Bordeaux, Bordeaux, France
| | - Valérie Aubin
- Fondation FondaMental, Créteil, France; Pôle de Psychiatrie, Centre Hospitalier Princesse Grace, Monaco
| | - Frank Bellivier
- Fondation FondaMental, Créteil, France; Université Paris Cité, INSERM UMR-S1144, AP-HPm GH Saint-Louis-Bariboisière-Fernand Widal, Pôle Neurosciences, Paris Optimisation Thérapeutique en Neuropsychopharmacologie OTeN, Paris, France; AP-HP, Groupe Hospitalo-Universitaire AP-HP Nord, DMU Neurosciences, Hôpital Fernand Widal, Département de Psychiatrie et de Médecine Addictologique, Paris, France
| | - Raoul Belzeaux-R
- Fondation FondaMental, Créteil, France; Univ. Montpellier & Department of Psychiatry, CHU de Montpellier, France
| | - Philippe Courtet
- Fondation FondaMental, Créteil, France; IGF, Univ. Montpellier, CNRS, INSERM, Department of Emergency Psychiatry and Acute Care, CHU Montpellier, Montpellier, France
| | - Caroline Dubertret
- Fondation FondaMental, Créteil, France; AP-HP, Groupe Hospitalo-Universitaire AP-HP Nord, DMU ESPRIT, Service de Psychiatrie et Addictologie, Hôpital Louis Mourier, Colombes, France, Université de Paris, Inserm UMR1266, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Bruno Etain
- Fondation FondaMental, Créteil, France; Université Paris Cité, INSERM UMR-S1144, AP-HPm GH Saint-Louis-Bariboisière-Fernand Widal, Pôle Neurosciences, Paris Optimisation Thérapeutique en Neuropsychopharmacologie OTeN, Paris, France; AP-HP, Groupe Hospitalo-Universitaire AP-HP Nord, DMU Neurosciences, Hôpital Fernand Widal, Département de Psychiatrie et de Médecine Addictologique, Paris, France
| | - Emmanuel Haffen
- Fondation FondaMental, Créteil, France; Université de Franche-Comté, UR 481 LINC, Service de Psychiatrie de l'Adulte, CIC-1431 INSERM, CHU de Besançon, F-2500, France
| | - Antoine Lefrere A
- Fondation FondaMental, Créteil, France; Pôle de Psychiatrie, Assistance Publique Hôpitaux de Marseille, Marseille, France, INT-UMR7289, CNRS Aix-Marseille Université, Marseille, France
| | - Pierre-Michel Llorca
- Fondation FondaMental, Créteil, France; Department of Psychiatry, CHU Clermont-Ferrand, University of Clermont Auvergne, CNRS, Clermont Auvergne INP, Institut Pascal (UMR 6602), Clermont-Ferrand, France
| | - Emilie Olié
- Fondation FondaMental, Créteil, France; IGF, Univ. Montpellier, CNRS, INSERM, Department of Emergency Psychiatry and Acute Care, CHU Montpellier, Montpellier, France
| | - Mircea Polosan
- Fondation FondaMental, Créteil, France; Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Ludovic Samalin
- Fondation FondaMental, Créteil, France; Department of Psychiatry, CHU Clermont-Ferrand, University of Clermont Auvergne, CNRS, Clermont Auvergne INP, Institut Pascal (UMR 6602), Clermont-Ferrand, France
| | - Raymund Schwan
- Université de Lorraine, Centre Psychothérapique de Nancy, Inserm U1254, Nancy, France
| | - Paul Roux
- Fondation FondaMental, Créteil, France; Centre Hospitalier de Versailles, Service Universitaire de Psychiatrie d'Adulte et d'Addictologie, Le Chesnay, France; Université Paris-Saclay & Université Versailles Saint-Quentin-En-Yvelines, INSERM UMR1018, Centre de recherche en Épidémiologie et Santé des Populations, Equipe DevPsy-DisAP, Paris, France
| | - Caroline Barau
- Plateforme de Ressources Biologiques, HU Henri Mondor, Créteil, France
| | - Jean Romain Richard
- INSERM U955 IMRB, Translational Neuropsychiatry laboratory, AP-HP, Hôpital Henri Mondor, DMU IMPACT, Fédération Hospitalo-Universitaire de Médecine de Précision en Psychiatrie (FHU ADAPT), Paris Est Créteil University (UPEC), ECNP Immuno-NeuroPsychiatry Network
| | - Ryad Tamouza
- INSERM U955 IMRB, Translational Neuropsychiatry laboratory, AP-HP, Hôpital Henri Mondor, DMU IMPACT, Fédération Hospitalo-Universitaire de Médecine de Précision en Psychiatrie (FHU ADAPT), Paris Est Créteil University (UPEC), ECNP Immuno-NeuroPsychiatry Network; Fondation FondaMental, Créteil, France
| | - Marion Leboyer
- INSERM U955 IMRB, Translational Neuropsychiatry laboratory, AP-HP, Hôpital Henri Mondor, DMU IMPACT, Fédération Hospitalo-Universitaire de Médecine de Précision en Psychiatrie (FHU ADAPT), Paris Est Créteil University (UPEC), ECNP Immuno-NeuroPsychiatry Network; Fondation FondaMental, Créteil, France.
| | - Ana C Andreazza
- Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Mitochondrial Innovation Initiative, MITO2i, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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Prasad SK, Acharjee A, Singh VV, Trigun SK, Acharjee P. Modulation of brain energy metabolism in hepatic encephalopathy: impact of glucose metabolic dysfunction. Metab Brain Dis 2024:10.1007/s11011-024-01407-7. [PMID: 39120853 DOI: 10.1007/s11011-024-01407-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024]
Abstract
Cerebral function is linked to a high level of metabolic activity and relies on glucose as its primary energy source. Glucose aids in the maintenance of physiological brain activities; as a result, a disruption in metabolism has a significant impact on brain function, launching a chain of events that leads to neuronal death. This metabolic insufficiency has been observed in a variety of brain diseases and neuroexcitotoxicity disorders, including hepatic encephalopathy. It is a significant neurological complication that develops in people with liver disease, ranging from asymptomatic abnormalities to coma. Hyperammonemia is the main neurotoxic villain in the development of hepatic encephalopathy and induces a wide range of complications in the brain. The neurotoxic effects of ammonia on brain function are thought to be mediated by impaired glucose metabolism. Accordingly, in this review, we provide an understanding of deranged brain energy metabolism, emphasizing the role of glucose metabolic dysfunction in the pathogenesis of hepatic encephalopathy. We also highlighted the differential metabolic profiles of brain cells and the status of metabolic cooperation between them. The major metabolic pathways that have been explored are glycolysis, glycogen metabolism, lactate metabolism, the pentose phosphate pathway, and the Krebs cycle. Furthermore, the lack of efficacy in current hepatic encephalopathy treatment methods highlights the need to investigate potential therapeutic targets for hepatic encephalopathy, with regulating deficient bioenergetics being a viable alternative in this case. This review also demonstrates the importance of the development of glucose metabolism-focused disease diagnostics and treatments, which are now being pursued for many ailments.
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Affiliation(s)
- Shambhu Kumar Prasad
- Biochemistry and Molecular Biology Unit, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Arup Acharjee
- Department of Zoology, University of Allahabad, Prayagraj, 211002, India.
| | - Vishal Vikram Singh
- Biochemistry and Molecular Biology Unit, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Surendra Kumar Trigun
- Biochemistry and Molecular Biology Unit, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Papia Acharjee
- Biochemistry and Molecular Biology Unit, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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Bagheri M, Habibzadeh S, Moeini M. Transient Changes in Cerebral Tissue Oxygen, Glucose, and Temperature by Microstrokes: A Computational Study. Microcirculation 2024; 31:e12872. [PMID: 38944839 DOI: 10.1111/micc.12872] [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: 02/17/2024] [Revised: 05/09/2024] [Accepted: 06/08/2024] [Indexed: 07/02/2024]
Abstract
OBJECTIVE This study focuses on evaluating the disruptions in key physiological parameters during microstroke events to assess their severity. METHODS A mathematical model was developed to simulate the changes in cerebral tissue pO2, glucose concentration, and temperature due to blood flow interruptions. The model considers variations in baseline cerebral blood flow (CBF), capillary density, and blood oxygen/glucose levels, as well as ambient temperature changes. RESULTS Simulations indicate that complete blood flow obstruction still allows for limited glucose availability, supporting nonoxidative metabolism and potentially exacerbating lactate buildup and acidosis. Partial obstructions decrease tissue pO2, with minimal impact on glucose level, which can remain almost unchanged or even slightly increase. Reduced CBF, capillary density, or blood oxygen due to aging or disease enhances hypoxia risk at lower obstruction levels, with capillary density having a significant effect on stroke severity by influencing both pO2 and glucose levels. Conditions could lead to co-occurrence of hypoxia/hypoglycemia or hypoxia/hyperglycemia, each worsening outcomes. Temperature effects were minimal in deep brain regions but varied near the skull by 0.2-0.8°C depending on ambient temperature. CONCLUSIONS The model provides insights into the conditions driving severe stroke outcomes based on estimated levels of hypoxia, hypoglycemia, hyperglycemia, and temperature changes.
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Affiliation(s)
- Marzieh Bagheri
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Sajjad Habibzadeh
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Mohammad Moeini
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
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5
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Soltanzadeh M, Blanchard S, Soucy JP, Benali H. Lactate's behavioral switch in the brain: An in-silico model. J Theor Biol 2023; 575:111648. [PMID: 37865309 DOI: 10.1016/j.jtbi.2023.111648] [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: 03/05/2023] [Revised: 06/26/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023]
Abstract
Emerging evidence emphasizes lactate's involvement in both physiological processes (energy metabolism, memory, etc.) and disease (traumatic brain injury, epilepsy, etc.). Furthermore, the usefulness of mathematical modeling in deciphering underlying dynamics of the brain to investigate lactate roles and mechanisms of action has been well established. Here, we analyze a novel mathematical model of brain lactate exchanges between four compartments: neurons, astrocytes, capillaries, and extracellular space. A system of four ordinary differential equations is proposed to explain interactions between these compartments. We first optimize and analyze the model's parameters under normal, resting state conditions, and then use it to simulate changes linked to elevated arterial lactate. Our results show that even though increased arterial lactate results in increased uptake by astrocytes and release to the extracellular space, it cannot strongly recover the initial drop in neuronal lactate concentration. Also, we show that the direction of lactate transport between the compartments is influenced by the maximum astrocyte production rate and the transport rate between astrocytes and extracellular space.
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Affiliation(s)
- Milad Soltanzadeh
- PERFORM Centre, Concordia University, Montreal, Canada; Electrical and Computer Engineering Department, Concordia University, Montreal, Canada.
| | - Solenna Blanchard
- University of Rennes, INSERM, LTSI-UMR 1099, F-35000, Rennes, France
| | - Jean-Paul Soucy
- PERFORM Centre, Concordia University, Montreal, Canada; Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, Canada.
| | - Habib Benali
- PERFORM Centre, Concordia University, Montreal, Canada; Electrical and Computer Engineering Department, Concordia University, Montreal, Canada.
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6
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Ma H, Zhou Y, Li Z, Zhu L, Li H, Zhang G, Wang J, Gong H, Xu D, Hua W, Liu P, Zhang X, Zhang Y, Zhang L, Hong B, Zhou W, Yang P, Liu J. Single-Cell RNA-Sequencing Analyses Revealed Heterogeneity and Dynamic Changes of Metabolic Pathways in Astrocytes at the Acute Phase of Ischemic Stroke. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1817721. [PMID: 35535357 PMCID: PMC9078813 DOI: 10.1155/2022/1817721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 03/10/2022] [Indexed: 11/17/2022]
Abstract
Astrocyte plays important roles in the pathogenesis of ischemic stroke and reperfusion injury. They intensively participate in the energy metabolism of the brain, while their heterogeneity and function after ischemic stroke remain controversial. By employing single-cell sequencing of mice cortex at 12 h after transient middle cerebral artery occlusion (tMCAO) and comparing with the similar published datasets of 24h after tMCAO, we uncover the cellular phenotypes and dynamic change of astrocytes at the acute phase of ischemic stroke. In this study, we separately identified 3 major subtypes of astrocytes at the 12 h-tMCAO-system and 24 h-tMCAO-system, indicated the significant differences in the expression of genes and metabolic pathways in the astrocytes between the two time nodes after ischemic stroke, and detected the major change in the energy metabolism. These results provided a comprehensive understanding of the characteristic changes of astrocytes after ischemic stroke and explored the potential astrocytic targets for neuroprotection.
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Affiliation(s)
- Hongyu Ma
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Yu Zhou
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Zifu Li
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Luojiang Zhu
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - He Li
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Guanghao Zhang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Jing Wang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Haiyi Gong
- Department of Orthopaedic Oncology, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Da Xu
- Department of Urology, Eastern Hepatobiliary Surgery Hospital, Naval Medical University, Shanghai, China
| | - Weilong Hua
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Pei Liu
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Xiaoxi Zhang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Yongxin Zhang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Lei Zhang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Bo Hong
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Wang Zhou
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Pengfei Yang
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Jianmin Liu
- Neurovascular Center, Changhai Hospital, Naval Medical University, Shanghai, China
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Forderhase AG, Styers HC, Lee CA, Sombers LA. Simultaneous voltammetric detection of glucose and lactate fluctuations in rat striatum evoked by electrical stimulation of the midbrain. Anal Bioanal Chem 2020; 412:6611-6624. [PMID: 32666141 PMCID: PMC7484411 DOI: 10.1007/s00216-020-02797-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 06/02/2020] [Accepted: 07/01/2020] [Indexed: 01/05/2023]
Abstract
Glucose and lactate provide energy for cellular function in the brain and serve as an important carbon source in the synthesis of a variety of biomolecules. Thus, there is a critical need to quantitatively monitor these molecules in situ on a time scale commensurate with neuronal function. In this work, carbon-fiber microbiosensors were coupled with fast-scan cyclic voltammetry to monitor glucose and lactate fluctuations at a discrete site within rat striatum upon electrical stimulation of the midbrain projection to the region. Systematic variation of stimulation parameters revealed the distinct dynamics by which glucose and lactate responded to the metabolic demand of synaptic function. Immediately upon stimulation, extracellular glucose and lactate availability rapidly increased. If stimulation was sufficiently intense, concentrations then immediately fell below baseline in response to incurred metabolic demand. The dynamics were dependent on stimulation frequency, such that more robust fluctuations were observed when the same number of pulses was delivered at a higher frequency. The rates at which glucose was supplied to, and depleted from, the local recording region were dependent on stimulation intensity, and glucose dynamics led those of lactate in response to the most substantial stimulations. Glucose fluctuated over a larger concentration range than lactate as stimulation duration increased, and glucose fell further from baseline concentrations. These real-time measurements provide an unprecedented direct comparison of glucose and lactate dynamics in response to metabolic demand elicited by neuronal activation. Graphical abstract.
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Affiliation(s)
- Alexandra G Forderhase
- Department of Chemistry, College of Sciences, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Hannah C Styers
- Department of Chemistry, College of Sciences, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Christie A Lee
- Department of Chemistry, College of Sciences, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Leslie A Sombers
- Department of Chemistry, College of Sciences, North Carolina State University, Raleigh, NC, 27695-8204, USA.
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC, 27695-8204, USA.
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8
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Serra PA, Arrigo P, Bacciu A, Zuncheddu D, Deliperi R, Antón Viana D, Monti P, Varoni MV, Sotgiu MA, Bandiera P, Rocchitta G. Real-time telemetry monitoring of oxygen in the central complex of freely-walking Gromphadorhina portentosa. PLoS One 2019; 14:e0224932. [PMID: 31710629 PMCID: PMC6844484 DOI: 10.1371/journal.pone.0224932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 10/24/2019] [Indexed: 11/21/2022] Open
Abstract
A new telemetric system for the electrochemical monitoring of dissolved oxygen is showed. The device, connected with two amperometric sensors, has been successfully applied to the wireless detection of the extracellular oxygen in the central complex of freely-walking Gromphadorhina portentosa. The unit was composed of a potentiostat, a two-channel sensor conditioning circuit, a microprocessor module, and a wireless serial transceiver. The amperometric signals were digitalized and sent to a notebook using a 2.4 GHz transceiver while a serial-to-USB converter was connected to a second transceiver for completing the communication bridge. The software, running on the laptop, allowed to save and graph the oxygen signals. The electronics showed excellent stability and the acquired data was linear in a range comprised between 0 and -165 nA, covering the entire range of oxygen concentrations. A series of experiments were performed to explore the dynamics of dissolved oxygen by exposing the animals to different gases (nitrogen, oxygen and carbon dioxide), to low temperature and anesthetic agents (chloroform and triethylamine). The resulting data are in agreement with previous O2 changes recorded in the brain of awake rats and mice. The proposed system, based on simple and inexpensive components, can constitute a new experimental model for the exploration of central complex neurochemistry and it can also work with oxidizing sensors and amperometric biosensors.
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Affiliation(s)
- Pier Andrea Serra
- Department of Medical, Surgical and Experimental Medicine, Medical School, University of Sassari, Sassari, Italy
- Institute of Sciences of Food Production, Italian National Research Council, Sassari, Italy
- Mediterranean Center for Disease Control, University of Sassari, Sassari, Italy
- * E-mail:
| | - Paola Arrigo
- Department of Medical, Surgical and Experimental Medicine, Medical School, University of Sassari, Sassari, Italy
| | - Andrea Bacciu
- Department of Medical, Surgical and Experimental Medicine, Medical School, University of Sassari, Sassari, Italy
| | - Daniele Zuncheddu
- Department of Medical, Surgical and Experimental Medicine, Medical School, University of Sassari, Sassari, Italy
| | - Riccardo Deliperi
- Department of Medical, Surgical and Experimental Medicine, Medical School, University of Sassari, Sassari, Italy
| | - Diego Antón Viana
- Department of Medical, Surgical and Experimental Medicine, Medical School, University of Sassari, Sassari, Italy
| | - Patrizia Monti
- Department of Medical, Surgical and Experimental Medicine, Medical School, University of Sassari, Sassari, Italy
| | - Maria Vittoria Varoni
- Department of Veterinary Medicine, Medical School, University of Sassari, Sassari, Italy
| | | | - Pasquale Bandiera
- Department of Biomedical Sciences, Medical School, University of Sassari, Sassari, Italy
| | - Gaia Rocchitta
- Department of Medical, Surgical and Experimental Medicine, Medical School, University of Sassari, Sassari, Italy
- Mediterranean Center for Disease Control, University of Sassari, Sassari, Italy
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9
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Ravera S, Torazza C, Bonifacino T, Provenzano F, Rebosio C, Milanese M, Usai C, Panfoli I, Bonanno G. Altered glucose catabolism in the presynaptic and perisynaptic compartments of SOD1 G93A mouse spinal cord and motor cortex indicates that mitochondria are the site of bioenergetic imbalance in ALS. J Neurochem 2019; 151:336-350. [PMID: 31282572 DOI: 10.1111/jnc.14819] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 05/22/2019] [Accepted: 07/03/2019] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis is an adult-onset neurodegenerative disease that develops because of motor neuron death. Several mechanisms occur supporting neurodegeneration, including mitochondrial dysfunction. Recently, we demonstrated that the synaptosomes from the spinal cord of SOD1G93A mice, an in vitro model of presynapses, displayed impaired mitochondrial metabolism at early pre-symptomatic stages of the disease, whereas perisynaptic astrocyte particles, or gliosomes, were characterized by mild energy impairment only at symptomatic stages. This work aimed to understand whether mitochondrial impairment is a consequence of upstream metabolic damage. We analyzed the critical pathways involved in glucose catabolism at presynaptic and perisynaptic compartments. Spinal cord and motor cortex synaptosomes from SOD1G93A mice displayed high activity of hexokinase and phosphofructokinase, key glycolysis enzymes, and of citrate synthase and malate dehydrogenase, key Krebs cycle enzymes, but did not display high lactate dehydrogenase activity, the key enzyme in lactate fermentation. This enhancement was evident in the spinal cord from the early stages of the disease and in the motor cortex at only symptomatic stages. Conversely, an increase in glycolysis and lactate fermentation activity, but not Krebs cycle activity, was observed in gliosomes from the spinal cord and motor cortex of SOD1G93A mice although only at the symptomatic stages of the disease. The cited enzymatic activities were enhanced in spinal cord and motor cortex homogenates, paralleling the time-course of the effect observed in synaptosomes and gliosomes. The observed metabolic modifications might be considered an attempt to restore altered energetic balance and indicate that mitochondria represent the ultimate site of bioenergetic impairment.
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Affiliation(s)
- Silvia Ravera
- Department of Pharmacy, Unit of Pharmacology and Toxicology and Center of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Carola Torazza
- Department of Pharmacy, Unit of Pharmacology and Toxicology and Center of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Tiziana Bonifacino
- Department of Pharmacy, Unit of Pharmacology and Toxicology and Center of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Francesca Provenzano
- Department of Pharmacy, Unit of Pharmacology and Toxicology and Center of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Claudia Rebosio
- Department of Pharmacy, Unit of Pharmacology and Toxicology and Center of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Marco Milanese
- Department of Pharmacy, Unit of Pharmacology and Toxicology and Center of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Cesare Usai
- Institute of Biophysics, National Research Council (CNR), Genoa, Italy
| | - Isabella Panfoli
- Department of Pharmacy, Laboratory of Biochemistry, University of Genoa, Genoa, Italy
| | - Giambattista Bonanno
- Department of Pharmacy, Unit of Pharmacology and Toxicology and Center of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy.,IRCCS San Martino Policlinic Hospital, Genoa, Italy
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10
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Hladky SB, Barrand MA. Elimination of substances from the brain parenchyma: efflux via perivascular pathways and via the blood-brain barrier. Fluids Barriers CNS 2018; 15:30. [PMID: 30340614 PMCID: PMC6194691 DOI: 10.1186/s12987-018-0113-6] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/30/2018] [Indexed: 02/06/2023] Open
Abstract
This review considers efflux of substances from brain parenchyma quantified as values of clearances (CL, stated in µL g-1 min-1). Total clearance of a substance is the sum of clearance values for all available routes including perivascular pathways and the blood-brain barrier. Perivascular efflux contributes to the clearance of all water-soluble substances. Substances leaving via the perivascular routes may enter cerebrospinal fluid (CSF) or lymph. These routes are also involved in entry to the parenchyma from CSF. However, evidence demonstrating net fluid flow inwards along arteries and then outwards along veins (the glymphatic hypothesis) is still lacking. CLperivascular, that via perivascular routes, has been measured by following the fate of exogenously applied labelled tracer amounts of sucrose, inulin or serum albumin, which are not metabolized or eliminated across the blood-brain barrier. With these substances values of total CL ≅ 1 have been measured. Substances that are eliminated at least partly by other routes, i.e. across the blood-brain barrier, have higher total CL values. Substances crossing the blood-brain barrier may do so by passive, non-specific means with CLblood-brain barrier values ranging from < 0.01 for inulin to > 1000 for water and CO2. CLblood-brain barrier values for many small solutes are predictable from their oil/water partition and molecular weight. Transporters specific for glucose, lactate and many polar substrates facilitate efflux across the blood-brain barrier producing CLblood-brain barrier values > 50. The principal route for movement of Na+ and Cl- ions across the blood-brain barrier is probably paracellular through tight junctions between the brain endothelial cells producing CLblood-brain barrier values ~ 1. There are large fluxes of amino acids into and out of the brain across the blood-brain barrier but only small net fluxes have been observed suggesting substantial reuse of essential amino acids and α-ketoacids within the brain. Amyloid-β efflux, which is measurably faster than efflux of inulin, is primarily across the blood-brain barrier. Amyloid-β also leaves the brain parenchyma via perivascular efflux and this may be important as the route by which amyloid-β reaches arterial walls resulting in cerebral amyloid angiopathy.
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Affiliation(s)
- Stephen B. Hladky
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Margery A. Barrand
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
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11
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Schurr A. Glycolysis Paradigm Shift Dictates a Reevaluation of Glucose and Oxygen Metabolic Rates of Activated Neural Tissue. Front Neurosci 2018; 12:700. [PMID: 30364172 PMCID: PMC6192285 DOI: 10.3389/fnins.2018.00700] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/18/2018] [Indexed: 01/31/2023] Open
Abstract
In 1988 two seminal studies were published, both instigating controversy. One concluded that “the energy needs of activated neural tissue are minimal, being fulfilled via the glycolytic pathway alone,” a conclusion based on the observation that neural activation increased glucose consumption, which was not accompanied by a corresponding increase in oxygen consumption (Fox et al., 1988). The second demonstrated that neural tissue function can be supported exclusively by lactate as the energy substrate (Schurr et al., 1988). While both studies continue to have their supporters and detractors, the present review attempts to clarify the issues responsible for the persistence of the controversies they have provoked and offer a possible rationalization. The concept that lactate rather than pyruvate, is the glycolytic end-product, both aerobically and anaerobically, and thus the real mitochondrial oxidative substrate, has gained a greater acceptance over the years. The idea of glycolysis as the sole ATP supplier for neural activation (glucose → lactate + 2ATP) continues to be controversial. Lactate oxidative utilization by activated neural tissue could explain the mismatch between glucose and oxygen consumption and resolve the existing disagreements among users of imaging methods to measure the metabolic rates of the two energy metabolic substrates. The postulate that the energy necessary for active neural tissue is supplied by glycolysis alone stems from the original aerobic glycolysis paradigm. Accordingly, glucose consumption is accompanied by oxygen consumption at 1–6 ratio. Since Fox et al. (1988) observed only a minimal if non-existent oxygen consumption compared to glucose consumption, their conclusion make sense. Nevertheless, considering (a) the shift in the paradigm of glycolysis (glucose → lactate; lactate + O2 + mitochondria → pyruvate → TCA cycle → CO2 + H2O + 17ATP); (b) that one mole of lactate oxidation requires only 50% of the amount of oxygen necessary for the oxidation of one mole of glucose; and (c) that lactate, as a mitochondrial substrate, is over eight times more efficient at ATP production than glucose as a glycolytic substrate, suggest that future studies of cerebral metabolic rates of activated neural tissue should include along with the measurements of CMRO2 and CMRglucose the measurement of CMRlactate.
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Affiliation(s)
- Avital Schurr
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Louisville, Louisville, KY, United States
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12
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Kakkar T, Thomas N, Kumi-Barimah E, Jose G, Saha S. Photoluminescence intensity ratio of Eu-conjugated lactates-A simple optical imaging technique for biomarker analysis for critical diseases. JOURNAL OF BIOPHOTONICS 2018; 11:e201700199. [PMID: 29094801 DOI: 10.1002/jbio.201700199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/30/2017] [Accepted: 10/31/2017] [Indexed: 06/07/2023]
Abstract
Instant measurement of elevated biomarkers such as lactic acid offers the most promising approaches for early treatment and prevention of many critical diseases including cardiac arrest, stroke, septic shock, trauma, liver dysfunction, as well as for monitoring lactic acid level during intense exercise. In the present study, a unique dependence of visible photoluminescence of Eu3+ ions resulting from 5 D0 to 7 FJ(J = 0,1,2,3,4) transitions, which can be exploited for rapid detection of biomarkers, both in vitro and ex vivo, has been reported. It is observed that the integrated intensity ratio of photoluminescence signals dominating at 591 and 616 nm originating from 5 D0 to 7 F2 and 5 D0 to 7 F1 transitions in Eu3+ ions can be used as a biosensing and bioimaging tool for detection of biomarkers released at disease states. The Eu3+ integrated photoluminescence intensity ratio approach reported herein for optical detection of lactates in blood serum, plasma and confocal imaging of brain tissues has very high potential for exploitation of this technique in both in vitro monitoring and in vivo bioimaging applications for the detection of biomarkers in various diseases states.
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Affiliation(s)
- Tarun Kakkar
- School of Chemical and Process Engineering, University of Leeds, Leeds, UK
| | - Nikita Thomas
- Leeds Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - Eric Kumi-Barimah
- School of Chemical and Process Engineering, University of Leeds, Leeds, UK
| | - Gin Jose
- School of Chemical and Process Engineering, University of Leeds, Leeds, UK
| | - Sikha Saha
- Leeds Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
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13
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Datta S, Chakrabarti N. Age related rise in lactate and its correlation with lactate dehydrogenase (LDH) status in post-mitochondrial fractions isolated from different regions of brain in mice. Neurochem Int 2018; 118:23-33. [PMID: 29678731 DOI: 10.1016/j.neuint.2018.04.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/11/2018] [Accepted: 04/11/2018] [Indexed: 02/06/2023]
Abstract
Rise in brain lactate is the hallmark of ageing. Separate studies report that ageing is associated with elevation of lactate level and alterations of lactate dehydrogenase (LDH)-A/B mRNA-expression-ratio in cerebral cortex and hippocampus. However, age related lactate rise in brain and its association with LDH status and their brain regional variations are still elusive. In the present study, level of lactate, LDH (A and B) activity and LDH-A expression were evaluated in post-mitochondrial fraction of tissues isolated from four different brain regions (cerebral cortex, hippocampus, substantia nigra and cerebellum) of young and aged mice. Lactate levels elevated in four brain regions with maximum rise in substantia nigra of aged mice. LDH-A protein expression and its activity decreased in cerebral cortex, hippocampus and substantia nigra without any changes of these parameters in cerebellum of aged mice. LDH-B activity decreased in hippocampus, substantia nigra and cerebellum whereas its activity remains unaltered in cerebral cortex of aged mice. Accordingly, the ratio of LDH-A/LDH-B-activity remains unaltered in hippocampus and substantia nigra, decreased in cerebral cortex and increased in cerebellum. Therefore, rise of lactate in three brain regions (cerebral cortex, hippocampus, substantia nigra) appeared to be not correlated with the alterations of its regulatory enzymes activities in these three brain regions, rather it supports the fact of involvement of other mechanisms, like lactate transport and/or aerobic/anaerobic metabolism as the possible cause(s) of lactate rise in these three brain regions. The increase in LDH-A/LDH-B-activity-ratio appeared to be positively correlated with elevated lactate level in cerebellum of aged mice. Overall, the present study indicates that the mechanism of rise in lactate in brain varies with brain regions where LDH status plays an important role during ageing.
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Affiliation(s)
- Siddhartha Datta
- Department of Physiology, University of Calcutta, Kolkata, West Bengal, India; UGC-CPEPA Centre for "Electro-physiological and Neuro-imaging Studies Including Mathematical Modelling", University of Calcutta, Kolkata, West Bengal, India.
| | - Nilkanta Chakrabarti
- Department of Physiology, University of Calcutta, Kolkata, West Bengal, India; UGC-CPEPA Centre for "Electro-physiological and Neuro-imaging Studies Including Mathematical Modelling", University of Calcutta, Kolkata, West Bengal, India; S. N. Pradhan Centre for Neurosciences, University of Calcutta, Kolkata, West Bengal, India.
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14
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Brosel S, Grothe B, Kunz L. An auditory brainstem nucleus as a model system for neuronal metabolic demands. Eur J Neurosci 2018; 47:222-235. [PMID: 29205598 DOI: 10.1111/ejn.13789] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 11/23/2017] [Accepted: 11/27/2017] [Indexed: 02/03/2023]
Abstract
The correlation between neuronal activity and metabolism is essential for coding, plasticity, neurological disorders and the interpretation of functional neuroimaging data. Most likely, metabolic requirements depend upon neuron type, and macroscopic energy demands vary with brain region. However, specific needs of individual neuron types are enigmatic. Therefore, we monitored metabolic activity in the lateral superior olive (LSO), an auditory brainstem nucleus containing only one neuron type. LSO neurons exhibit extreme but well-described biophysics with firing rates of several hundred hertz and low input resistances of a few megaohms. We recorded changes in NADH and flavin adenine dinucleotide (FAD) autofluorescence and O2 concentration in acute brainstem slices of Mongolian gerbils (Meriones unguiculatus) following electrical stimulation. The LSO shows the typical biphasic NADH/FAD response up to a physiologically relevant frequency of 400 Hz. In the same animal, we compared the LSO with the hippocampal CA1 region and the cerebral cortex. The rate of NADH/FADH2 consumption and regeneration was slowest in LSO. However, frequency dependence was only similar during the consumption phase but varied during regeneration within the three brain regions. Changes in NADH, FAD and O2 levels and blocking metabolic reactions indicate a pronounced contribution of mitochondrial oxidative phosphorylation in the LSO which is known for the other brain regions as well. Lactate transport and interconversion are involved in LSO metabolism as we found in immunohistochemical and pharmacological experiments. Our findings show that the LSO represents an apt, biophysically distinct model for brain metabolism and that neuronal properties determine metabolic needs.
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Affiliation(s)
- Sonja Brosel
- Department Biology II, Division of Neurobiology, LMU Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Benedikt Grothe
- Department Biology II, Division of Neurobiology, LMU Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Lars Kunz
- Department Biology II, Division of Neurobiology, LMU Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
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15
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Liu B, Teschemacher AG, Kasparov S. Neuroprotective potential of astroglia. J Neurosci Res 2017; 95:2126-2139. [PMID: 28836687 DOI: 10.1002/jnr.24140] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 07/14/2017] [Accepted: 07/24/2017] [Indexed: 12/13/2022]
Abstract
Astroglia are the homoeostatic cells of the central nervous system, which participate in all essential functions of the brain. Astrocytes support neuronal networks by handling water and ion fluxes, transmitter clearance, provision of antioxidants, and metabolic precursors and growth factors. The critical dependence of neurons on constant support from the astrocytes confers astrocytes with intrinsic neuroprotective properties. On the other hand, loss of astrocytic support or their pathological transformation compromises neuronal functionality and viability. Manipulating neuroprotective functions of astrocytes is thus an important strategy to enhance neuronal survival and improve outcomes in disease states. © 2017 The Authors Journal of Neuroscience Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Beihui Liu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom
| | - A G Teschemacher
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom
| | - Sergey Kasparov
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom.,Institute of Living Systems, School of Life Sciences, Immanuel Kant Baltic Federal University, Kaliningrad, Russian Federation
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16
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17
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Proia P, Di Liegro CM, Schiera G, Fricano A, Di Liegro I. Lactate as a Metabolite and a Regulator in the Central Nervous System. Int J Mol Sci 2016; 17:E1450. [PMID: 27598136 PMCID: PMC5037729 DOI: 10.3390/ijms17091450] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 08/22/2016] [Accepted: 08/25/2016] [Indexed: 12/21/2022] Open
Abstract
More than two hundred years after its discovery, lactate still remains an intriguing molecule. Considered for a long time as a waste product of metabolism and the culprit behind muscular fatigue, it was then recognized as an important fuel for many cells. In particular, in the nervous system, it has been proposed that lactate, released by astrocytes in response to neuronal activation, is taken up by neurons, oxidized to pyruvate and used for synthesizing acetyl-CoA to be used for the tricarboxylic acid cycle. More recently, in addition to this metabolic role, the discovery of a specific receptor prompted a reconsideration of its role, and lactate is now seen as a sort of hormone, even involved in processes as complex as memory formation and neuroprotection. As a matter of fact, exercise offers many benefits for our organisms, and seems to delay brain aging and neurodegeneration. Now, exercise induces the production and release of lactate into the blood which can reach the liver, the heart, and also the brain. Can lactate be a beneficial molecule produced during exercise, and offer neuroprotection? In this review, we summarize what we have known on lactate, discussing the roles that have been attributed to this molecule over time.
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Affiliation(s)
- Patrizia Proia
- Department of Psychological, Pedagogical and Educational Sciences, Sport and Exercise Sciences Research Unit, University of Palermo, Palermo I-90128, Italy.
| | - Carlo Maria Di Liegro
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Gabriella Schiera
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Anna Fricano
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Italia Di Liegro
- Department of Experimental Biomedicine and Clinical Neurosciences (BIONEC), University of Palermo, Palermo I-90127, Italy.
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18
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Steinman MQ, Gao V, Alberini CM. The Role of Lactate-Mediated Metabolic Coupling between Astrocytes and Neurons in Long-Term Memory Formation. Front Integr Neurosci 2016; 10:10. [PMID: 26973477 PMCID: PMC4776217 DOI: 10.3389/fnint.2016.00010] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/15/2016] [Indexed: 01/07/2023] Open
Abstract
Long-term memory formation, the ability to retain information over time about an experience, is a complex function that affects multiple behaviors, and is an integral part of an individual's identity. In the last 50 years many scientists have focused their work on understanding the biological mechanisms underlying memory formation and processing. Molecular studies over the last three decades have mostly investigated, or given attention to, neuronal mechanisms. However, the brain is composed of different cell types that, by concerted actions, cooperate to mediate brain functions. Here, we consider some new insights that emerged from recent studies implicating astrocytic glycogen and glucose metabolisms, and particularly their coupling to neuronal functions via lactate, as an essential mechanism for long-term memory formation.
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Affiliation(s)
| | - Virginia Gao
- Center for Neural Science, New York University New York, NY, USA
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19
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Cuellar-Baena S, Landeck N, Sonnay S, Buck K, Mlynarik V, In 't Zandt R, Kirik D. Assessment of brain metabolite correlates of adeno-associated virus-mediated over-expression of human alpha-synuclein in cortical neurons by in vivo (1) H-MR spectroscopy at 9.4 T. J Neurochem 2016; 137:806-19. [PMID: 26811128 DOI: 10.1111/jnc.13547] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 12/19/2022]
Abstract
In this study, we used proton-localized spectroscopy ((1) H-MRS) for the acquisition of the neurochemical profile longitudinally in a novel rat model of human wild-type alpha-synuclein (α-syn) over-expression. Our goal was to find out if the increased α-syn load in this model could be linked to changes in metabolites in the frontal cortex. Animals injected with AAV vectors encoding for human α-syn formed the experimental group, whereas green fluorescent protein expressing animals were used as the vector-treated control group and a third group of uninjected animals were used as naïve controls. Data were acquired at 2, 4, and 8 month time points. Nineteen metabolites were quantified in the MR spectra using LCModel software. On the basis of 92 spectra, we evaluated any potential gender effect and found that lactate (Lac) levels were lower in males compared to females, while the opposite was observed for ascorbate (Asc). Next, we assessed the effect of age and found increased levels of GABA, Tau, and GPC+PCho. Finally, we analyzed the effect of treatment and found that Lac levels (p = 0.005) were specifically lower in the α-syn group compared to the green fluorescent protein and control groups. In addition, Asc levels (p = 0.05) were increased in the vector-injected groups, whereas glucose levels remained unchanged. This study indicates that the metabolic switch between glucose-lactate could be detectable in vivo and might be modulated by Asc. No concomitant changes were found in markers of neuronal integrity (e.g., N-acetylaspartate) consistent with the fact that α-syn over-expression in cortical neurons did not result in neurodegeneration in this model. We acquired the neurochemical profile longitudinally in a rat model of human wild-type alpha-synuclein (α-syn) over-expression in cortical neurons. We found that Lactate levels were reduced in the α-syn group compared to the control groups and Ascorbate levels were increased in the vector-injected groups. No changes were found in markers of neuronal integrity consistent with the fact that α-syn over-expression did not result in frank neurodegeneration.
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Affiliation(s)
- Sandra Cuellar-Baena
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Natalie Landeck
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Sarah Sonnay
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden.,Laboratory of functional and metabolic imaging (LIFMET), École Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
| | - Kerstin Buck
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Vladimir Mlynarik
- Laboratory of functional and metabolic imaging (LIFMET), École Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland.,Department of Radiology and Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - René In 't Zandt
- Lund University BioImaging Center, Lund University, Lund, Sweden
| | - Deniz Kirik
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden.,Lund University BioImaging Center, Lund University, Lund, Sweden
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20
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Abstract
BACKGROUND Lactate is traditionally seen as a marker of ischemia and a waste product of anaerobic glycolysis. In the last thirty years a more beneficial side of lactate as an alternative 'glucose sparing' fuel has been demonstrated. However, the translation of these growing insights to clinical practice seems to appear with great delay. METHODS A review of the literature was performed, focusing on glucose and lactate in relation to cerebral energy metabolism, in the context of four typical clinical situations, namely (transient states of) low glucose availability for the brain due to hypoglycemia, combined with high blood lactate concentrations; permanent neuroglycopenia; lactic acidosis in mitochondrial disorders; and ischemic as well as traumatic brain injury. RESULTS Lactate is thought to be an alternative fuel in the brain of patients with glucose transporter type 1 deficiency syndrome and glycogen storage disease, and it has been demonstrated that lactate might have a protective role in ischemic and traumatic brain injury. CONCLUSION Lactate has an apparently largely ignored, but potential beneficial role in the clinical management of several neurologic disorders.
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21
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Falkowska A, Gutowska I, Goschorska M, Nowacki P, Chlubek D, Baranowska-Bosiacka I. Energy Metabolism of the Brain, Including the Cooperation between Astrocytes and Neurons, Especially in the Context of Glycogen Metabolism. Int J Mol Sci 2015; 16:25959-81. [PMID: 26528968 PMCID: PMC4661798 DOI: 10.3390/ijms161125939] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/27/2015] [Accepted: 10/16/2015] [Indexed: 01/15/2023] Open
Abstract
Glycogen metabolism has important implications for the functioning of the brain, especially the cooperation between astrocytes and neurons. According to various research data, in a glycogen deficiency (for example during hypoglycemia) glycogen supplies are used to generate lactate, which is then transported to neighboring neurons. Likewise, during periods of intense activity of the nervous system, when the energy demand exceeds supply, astrocyte glycogen is immediately converted to lactate, some of which is transported to the neurons. Thus, glycogen from astrocytes functions as a kind of protection against hypoglycemia, ensuring preservation of neuronal function. The neuroprotective effect of lactate during hypoglycemia or cerebral ischemia has been reported in literature. This review goes on to emphasize that while neurons and astrocytes differ in metabolic profile, they interact to form a common metabolic cooperation.
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Affiliation(s)
- Anna Falkowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Broniewskiego 24, 71-460 Szczecin, Poland.
| | - Marta Goschorska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Przemysław Nowacki
- Department of Neurology, Pomeranian Medical University, Unii Lubelskiej 1, 71-225 Szczecin, Poland.
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
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22
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Schurr A. Cerebral glycolysis: a century of persistent misunderstanding and misconception. Front Neurosci 2014; 8:360. [PMID: 25477776 PMCID: PMC4237041 DOI: 10.3389/fnins.2014.00360] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/21/2014] [Indexed: 11/18/2022] Open
Abstract
Since its discovery in 1780, lactate (lactic acid) has been blamed for almost any illness outcome in which its levels are elevated. Beginning in the mid-1980s, studies on both muscle and brain tissues, have suggested that lactate plays a role in bioenergetics. However, great skepticism and, at times, outright antagonism has been exhibited by many to any perceived role for this monocarboxylate in energy metabolism. The present review attempts to trace the negative attitudes about lactate to the first four or five decades of research on carbohydrate metabolism and its dogma according to which lactate is a useless anaerobic end-product of glycolysis. The main thrust here is the review of dozens of scientific publications, many by the leading scientists of their times, through the first half of the twentieth century. Consequently, it is concluded that there exists a barrier, described by Howard Margolis as “habit of mind,” that many scientists find impossible to cross. The term suggests “entrenched responses that ordinarily occur without conscious attention and that, even if noticed, are hard to change.” Habit of mind has undoubtedly played a major role in the above mentioned negative attitudes toward lactate. As early as the 1920s, scientists investigating brain carbohydrate metabolism had discovered that lactate can be oxidized by brain tissue preparations, yet their own habit of mind redirected them to believe that such an oxidation is simply a disposal mechanism of this “poisonous” compound. The last section of the review invites the reader to consider a postulated alternative glycolytic pathway in cerebral and, possibly, in most other tissues, where no distinction is being made between aerobic and anaerobic glycolysis; lactate is always the glycolytic end product. Aerobically, lactate is readily shuttled and transported into the mitochondrion, where it is converted to pyruvate via a mitochondrial lactate dehydrogenase (mLDH) and then is entered the tricarboxylic acid (TCA) cycle.
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Affiliation(s)
- Avital Schurr
- Department of Anesthesiology and Perioperative Medicine, University of Louisville School of Medicine Louisville, KY, USA
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23
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Glucose detection at attomole levels using dynamic light scattering and gold nanoparticles. Sci China Chem 2014. [DOI: 10.1007/s11426-014-5079-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Farina D, Alvau MD, Puggioni G, Calia G, Bazzu G, Migheli R, Sechi O, Rocchitta G, Desole MS, Serra PA. Implantable (Bio)sensors as new tools for wireless monitoring of brain neurochemistry in real time. World J Pharmacol 2014; 3:1-17. [DOI: 10.5497/wjp.v3.i1.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 05/01/2014] [Accepted: 05/29/2014] [Indexed: 02/06/2023] Open
Abstract
Implantable electrochemical microsensors are characterized by high sensitivity, while amperometric biosensors are very selective in virtue of the biological detecting element. Each sensor, specific for every neurochemical species, is a miniaturized high-technology device resulting from the combination of several factors: electrode material, shielding polymers, applied electrochemical technique, and in the case of biosensors, biological sensing material, stabilizers, and entrapping chemical nets. In this paper, we summarize the available technology for the in vivo electrochemical monitoring of neurotransmitters (dopamine, norepinephrine, serotonin, acetylcholine, and glutamate), bioenergetic substrates (glucose, lactate, and oxygen), neuromodulators (ascorbic acid and nitric oxide), and exogenous molecules such as ethanol. We also describe the most represented biotelemetric technologies in order to wirelessly transmit the signals of the above-listed neurochemicals. Implantable (Bio)sensors, integrated into miniaturized telemetry systems, represent a new generation of analytical tools that could be used for studying the brain’s physiology and pathophysiology and the effects of different drugs (or toxic chemicals such as ethanol) on neurochemical systems.
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Hemodynamic and metabolic correlates of perinatal white matter injury severity. PLoS One 2013; 8:e82940. [PMID: 24416093 PMCID: PMC3886849 DOI: 10.1371/journal.pone.0082940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/07/2013] [Indexed: 11/21/2022] Open
Abstract
Background and Purpose Although the spectrum of perinatal white matter injury (WMI) in preterm infants is shifting from cystic encephalomalacia to milder forms of WMI, the factors that contribute to this changing spectrum are unclear. We hypothesized that the variability in WMI quantified by immunohistochemical markers of inflammation could be correlated with the severity of impaired blood oxygen, glucose and lactate. Methods We employed a preterm fetal sheep model of in utero moderate hypoxemia and global severe but not complete cerebral ischemia that reproduces the spectrum of human WMI. Since there is small but measurable residual brain blood flow during occlusion, we sought to determine if the metabolic state of the residual arterial blood was associated with severity of WMI. Near the conclusion of hypoxia-ischemia, we recorded cephalic arterial blood pressure, blood oxygen, glucose and lactate levels. To define the spectrum of WMI, an ordinal WMI rating scale was compared against an unbiased quantitative image analysis protocol that provided continuous histo-pathological outcome measures for astrogliosis and microgliosis derived from the entire white matter. Results A spectrum of WMI was observed that ranged from diffuse non-necrotic lesions to more severe injury that comprised discrete foci of microscopic or macroscopic necrosis. Residual arterial pressure, oxygen content and blood glucose displayed a significant inverse association with WMI and lactate concentrations were directly related. Elevated glucose levels were the most significantly associated with less severe WMI. Conclusions Our results suggest that under conditions of hypoxemia and severe cephalic hypotension, WMI severity measured using unbiased immunohistochemical measurements correlated with several physiologic parameters, including glucose, which may be a useful marker of fetal response to hypoxia or provide protection against energy failure and more severe WMI.
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Rocchitta G, Secchi O, Alvau MD, Farina D, Bazzu G, Calia G, Migheli R, Desole MS, O'Neill RD, Serra PA. Simultaneous telemetric monitoring of brain glucose and lactate and motion in freely moving rats. Anal Chem 2013; 85:10282-8. [PMID: 24102201 DOI: 10.1021/ac402071w] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A new telemetry system for simultaneous detection of extracellular brain glucose and lactate and motion is presented. The device consists of dual-channel, single-supply miniature potentiostat-I/V converter, a microcontroller unit, a signal transmitter, and a miniaturized microvibration sensor. Although based on simple and inexpensive components, the biotelemetry device has been used for accurate transduction of the anodic oxidation currents generated on the surface of implanted glucose and lactate biosensors and animal microvibrations. The device was characterized and validated in vitro before in vivo experiments. The biosensors were implanted in the striatum of freely moving animals and the biotelemetric device was fixed to the animal's head. Physiological and pharmacological stimulations were given in order to induce striatal neural activation and to modify the motor behavior in awake, untethered animals.
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Affiliation(s)
- Gaia Rocchitta
- Department of Clinical and Experimental Medicine, Medical School, University of Sassari , Viale S. Pietro 43/b, 07100 Sassari, Italy
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Effects of the neurotoxin MPTP and pargyline protection on extracellular energy metabolites and dopamine levels in the striatum of freely moving rats. Brain Res 2013; 1538:159-71. [PMID: 24080403 DOI: 10.1016/j.brainres.2013.09.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 08/27/2013] [Accepted: 09/24/2013] [Indexed: 12/25/2022]
Abstract
The neurotoxin MPTP is known to induce dopamine release and depletion of ATP in the striatum of rats. Therefore, we studied the changes induced by MPTP and pargyline protection both on striatal dopamine release and on extracellular energy metabolites in freely moving rats, using dual asymmetric-flow microdialysis. A dual microdialysis probe was inserted in the right striatum of rats. MPTP (25mg/kg, 15mg/kg, 10mg/kg) was intraperitoneally administered for three consecutive days. MAO-B inhibitor pargyline (15mg/kg) was systemically administered before neurotoxin administration. The first MPTP dose induced an increase in dialysate dopamine and a decrease of DOPAC levels in striatal dialysate. After the first neurotoxin administration, increases in striatal glucose, lactate, pyruvate, lactate/pyruvate (L/P) and lactate/glucose (L/G) ratios were observed. Subsequent MPTP administrations showed a progressive reduction of dopamine, glucose and pyruvate levels with a concomitant further increase in lactate levels and L/P and L/G ratios. At day 1, pargyline pre-treatment attenuated the MPTP-induced changes in all studied analytes. Starting from day 2, pargyline prevented the depletion of dopamine, glucose and pyruvate while reduced the increase of lactate, L/P ratio and L/G ratio. These in vivo results suggest a pargyline neuroprotection role against the MPTP-induced energetic impairment consequent to mitochondrial damage. This neuroprotective effect was confirmed by TH immunostaining of the substantia nigra.
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Pirchl M, Marksteiner J, Humpel C. Effects of acidosis on brain capillary endothelial cells and cholinergic neurons: relevance to vascular dementia and Alzheimer's disease. Neurol Res 2013; 28:657-64. [PMID: 16945219 DOI: 10.1179/016164106x130371] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Alzheimer's disease is a progressive brain disorder which is neuropathologically characterized by an increased number of beta-amyloid plaques, tau pathology and synapse loss. Recent research suggests that vascular pathology may be also important for the development and progression of Alzheimer's disease. It is still unknown whether there is a relation between damage of brain capillary endothelial cells (BCEC) and subsequent cholinergic cell death. The aim of this study was to examine the effects of acidosis on cell death of BCEC and cholinergic neurons in an organotypic brain slice model. We show that BCEC were heavily damaged in medium at pH<6.6. Cholinergic neurons incubated in medium pH 6.0 degenerated within 2-3 days and were not rescued by nerve growth factor (NGF). Lactate did not affect the survival of BCEC or cholinergic neurons. Both BCEC and cholinergic cells were not affected at pH 7.4, 7.0 or 6.6. It is concluded that both endothelial cells and cholinergic neurons have a high capacity to compensate for pH changes. At a certain pH, however, the vascular and neuronal cells show the same vulnerability, indicating that a low pH is deleterious for the cerebral microenvironment. Future studies are necessary to explore whether temporary pH changes could be responsible for cerebrovascular damage and cholinergic cell death. Acidosis may play an important role in the development of vascular dementia and Alzheimer's disease.
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Affiliation(s)
- Michael Pirchl
- Laboratory of Experimental Alzheimer's Research, Department of General Psychiatry, Innsbruck Medical University, Austria
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Lu X, Cheng H, Huang P, Yang L, Yu P, Mao L. Hybridization of bioelectrochemically functional infinite coordination polymer nanoparticles with carbon nanotubes for highly sensitive and selective in vivo electrochemical monitoring. Anal Chem 2013; 85:4007-13. [PMID: 23496088 DOI: 10.1021/ac303743a] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This study demonstrates the formation of a three-dimensional conducting framework through hybridization of bioelectrochemically active infinite coordination polymer (ICP) nanoparticles with single-walled carbon nanotubes (SWNTs) for highly sensitive and selective in vivo electrochemical monitoring with combination with in vivo microdialysis. The bioelectrochemically active ICP nanoparticles are synthesized through the self-assembly process of NAD(+) and Tb(3+), in which all biosensing elements including an electrocatalyst (i.e., methylene green, MG), cofactor (i.e., β-nicotinamide adenine dinucleotide, NAD(+)), and enzyme (i.e., glucose dehydrogenase, GDH) are adaptively encapsulated. The ICP/SWNT-based biosensors are simply prepared by drop-coating the as-formed ICP/SWNT nanocomposite onto a glassy carbon substrate. Electrochemical studies demonstrate that the simply prepared ICP/SWNT-based biosensors exhibit excellent biosensing properties with a higher sensitivity and stability than the ICP-based biosensors prepared only with ICP nanoparticles (i.e., without hybridization of SWNTs). By using a GDH-based electrochemical biosensor as an example, we demonstrate a technically simple yet effective online electroanalytical platform for continuously monitoring glucose in the brain of guinea pigs with the ICP/SWNT-based biosensor as an online detector in a continuous-flow system combined with in vivo microdialysis. Under the experimental conditions employed here, the dynamic linear range for glucose with the ICP/SWNT-biosensor is from 50 to 1000 μM. Moreover, in vivo selectivity investigations with the biosensors prepared by the GDH-free ICPs reveal that ICP/SWNT-based biosensors are very selective for the measurement of glucose in the cerebral system. The basal level of glucose in the microdialysates from the striatum of guinea pigs is determined to be 0.31 ± 0.03 mM (n = 3). The study offers a simple route to the preparation of electrochemical biosensors, which is envisaged to be particularly useful for probing the chemical events involved in some physiological and pathological processes.
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Affiliation(s)
- Xulin Lu
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China
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The metabolism of neurons and astrocytes through mathematical models. Ann Biomed Eng 2012; 40:2328-44. [PMID: 23001357 DOI: 10.1007/s10439-012-0643-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 08/16/2012] [Indexed: 10/27/2022]
Abstract
Mathematical modeling of the energy metabolism of brain cells plays a central role in understanding data collected with different imaging modalities, and in making predictions based on them. During the last decade, several sophisticated brain metabolism models have appeared. Unfortunately, the picture of the metabolic details that emerges from them is far from coherent: while each model has its justification and is in agreement with some experimental data, some of the predictions of different models can diverge from each other significantly. In this article, we review some of the recent published models, emphasizing similarities and differences between them to understand where the differences in predictions stem from. In that context we present a probabilistic approach, which rather than assigning fixed values to the model parameters, regard them as random variables whose distributions are inferred on in the light of stoichiometric information and different observations. The probabilistic approach reveals how much intrinsic variability a metabolic system may contain, which in turn may be a valid explanation of the different findings.
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Campos F, Pérez-Mato M, Agulla J, Blanco M, Barral D, Almeida Á, Brea D, Waeber C, Castillo J, Ramos-Cabrer P. Glutamate excitoxicity is the key molecular mechanism which is influenced by body temperature during the acute phase of brain stroke. PLoS One 2012; 7:e44191. [PMID: 22952923 PMCID: PMC3429451 DOI: 10.1371/journal.pone.0044191] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 07/30/2012] [Indexed: 11/19/2022] Open
Abstract
Glutamate excitotoxicity, metabolic rate and inflammatory response have been associated to the deleterious effects of temperature during the acute phase of stroke. So far, the association of temperature with these mechanisms has been studied individually. However, the simultaneous study of the influence of temperature on these mechanisms is necessary to clarify their contributions to temperature-mediated ischemic damage. We used non-invasive Magnetic Resonance Spectroscopy to simultaneously measure temperature, glutamate excitotoxicity and metabolic rate in the brain in animal models of ischemia. The immune response to ischemia was measured through molecular serum markers in peripheral blood. We submitted groups of animals to different experimental conditions (hypothermia at 33°C, normothermia at 37°C and hyperthermia at 39°C), and combined these conditions with pharmacological modulation of glutamate levels in the brain through systemic injections of glutamate and oxaloacetate. We show that pharmacological modulation of glutamate levels can neutralize the deleterious effects of hyperthermia and the beneficial effects of hypothermia, however the analysis of the inflammatory response and metabolic rate, demonstrated that their effects on ischemic damage are less critical than glutamate excitotoxity. We conclude that glutamate excitotoxicity is the key molecular mechanism which is influenced by body temperature during the acute phase of brain stroke.
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Affiliation(s)
- Francisco Campos
- Clinical Neurosciences Research Laboratory, Department of Neurology, Hospital Universitario de Santiago, University of Santiago de Compostela, IDIS, Santiago de Compostela, Spain
- * E-mail: (PRC); (FC)
| | - María Pérez-Mato
- Clinical Neurosciences Research Laboratory, Department of Neurology, Hospital Universitario de Santiago, University of Santiago de Compostela, IDIS, Santiago de Compostela, Spain
| | - Jesús Agulla
- Clinical Neurosciences Research Laboratory, Department of Neurology, Hospital Universitario de Santiago, University of Santiago de Compostela, IDIS, Santiago de Compostela, Spain
| | - Miguel Blanco
- Clinical Neurosciences Research Laboratory, Department of Neurology, Hospital Universitario de Santiago, University of Santiago de Compostela, IDIS, Santiago de Compostela, Spain
| | - David Barral
- Clinical Neurosciences Research Laboratory, Department of Neurology, Hospital Universitario de Santiago, University of Santiago de Compostela, IDIS, Santiago de Compostela, Spain
| | - Ángeles Almeida
- Research Unit, Hospital Universitario de Salamanca and Institute of Health Sciences of Castilla and León, Salamanca, Spain
- Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain
| | - David Brea
- Clinical Neurosciences Research Laboratory, Department of Neurology, Hospital Universitario de Santiago, University of Santiago de Compostela, IDIS, Santiago de Compostela, Spain
| | - Christian Waeber
- Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - José Castillo
- Clinical Neurosciences Research Laboratory, Department of Neurology, Hospital Universitario de Santiago, University of Santiago de Compostela, IDIS, Santiago de Compostela, Spain
| | - Pedro Ramos-Cabrer
- Clinical Neurosciences Research Laboratory, Department of Neurology, Hospital Universitario de Santiago, University of Santiago de Compostela, IDIS, Santiago de Compostela, Spain
- * E-mail: (PRC); (FC)
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Hall RJ, Shenkin SD, Maclullich AMJ. A systematic literature review of cerebrospinal fluid biomarkers in delirium. Dement Geriatr Cogn Disord 2012; 32:79-93. [PMID: 21876357 DOI: 10.1159/000330757] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/13/2011] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Cerebrospinal fluid (CSF) analysis has great potential to advance understanding of delirium pathophysiology. METHODS A systematic literature review of CSF studies of DSM or ICD delirium was performed. RESULTS In 8 studies of 235 patients, delirium was associated with: elevated serotonin metabolites, interleukin-8, cortisol, lactate and protein, and reduced somatostatin, β-endorphin and neuron-specific enolase. Elevated acetylcholinesterase predicted poor outcome after delirium and higher dopamine metabolites were associated with psychotic features. CONCLUSIONS No clear conclusions emerged, but the current literature suggests multiple areas for further investigation with more detailed studies.
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Affiliation(s)
- Roanna J Hall
- Edinburgh Delirium Research Group, Geriatric Medicine, Division of Health Sciences, School of Clinical Sciences and Community Health, UK. roanna.hall @ ed.ac.uk
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Schurr A, Gozal E. Aerobic production and utilization of lactate satisfy increased energy demands upon neuronal activation in hippocampal slices and provide neuroprotection against oxidative stress. Front Pharmacol 2012; 2:96. [PMID: 22275901 PMCID: PMC3257848 DOI: 10.3389/fphar.2011.00096] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 12/23/2011] [Indexed: 12/21/2022] Open
Abstract
Ever since it was shown for the first time that lactate can support neuronal function in vitro as a sole oxidative energy substrate, investigators in the field of neuroenergetics have been debating the role, if any, of this glycolytic product in cerebral energy metabolism. Our experiments employed the rat hippocampal slice preparation with electrophysiological and biochemical methodologies. The data generated by these experiments (a) support the hypothesis that lactate, not pyruvate, is the end-product of cerebral aerobic glycolysis; (b) indicate that lactate plays a major and crucial role in affording neural tissue to respond adequately to glutamate excitation and to recover unscathed post-excitation; (c) suggest that neural tissue activation is accompanied by aerobic lactate and NADH production, the latter being produced when the former is converted to pyruvate by mitochondrial lactate dehydrogenase (mLDH); (d) imply that NADH can be utilized as an endogenous scavenger of reactive oxygen species (ROS) to provide neuroprotection against ROS-induced neuronal damage.
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Affiliation(s)
- Avital Schurr
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Louisville Louisville, KY, USA.
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Newman LA, Korol DL, Gold PE. Lactate produced by glycogenolysis in astrocytes regulates memory processing. PLoS One 2011; 6:e28427. [PMID: 22180782 PMCID: PMC3236748 DOI: 10.1371/journal.pone.0028427] [Citation(s) in RCA: 357] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 11/08/2011] [Indexed: 01/06/2023] Open
Abstract
When administered either systemically or centrally, glucose is a potent enhancer of memory processes. Measures of glucose levels in extracellular fluid in the rat hippocampus during memory tests reveal that these levels are dynamic, decreasing in response to memory tasks and loads; exogenous glucose blocks these decreases and enhances memory. The present experiments test the hypothesis that glucose enhancement of memory is mediated by glycogen storage and then metabolism to lactate in astrocytes, which provide lactate to neurons as an energy substrate. Sensitive bioprobes were used to measure brain glucose and lactate levels in 1-sec samples. Extracellular glucose decreased and lactate increased while rats performed a spatial working memory task. Intrahippocampal infusions of lactate enhanced memory in this task. In addition, pharmacological inhibition of astrocytic glycogenolysis impaired memory and this impairment was reversed by administration of lactate or glucose, both of which can provide lactate to neurons in the absence of glycogenolysis. Pharmacological block of the monocarboxylate transporter responsible for lactate uptake into neurons also impaired memory and this impairment was not reversed by either glucose or lactate. These findings support the view that astrocytes regulate memory formation by controlling the provision of lactate to support neuronal functions.
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Affiliation(s)
- Lori A Newman
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America.
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Diringer MN, Zazulia AR, Powers WJ. Does Ischemia Contribute to Energy Failure in Severe TBI? Transl Stroke Res 2011; 2:517-23. [DOI: 10.1007/s12975-011-0119-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 10/12/2011] [Accepted: 10/14/2011] [Indexed: 12/12/2022]
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Bazzu G, Biosa A, Farina D, Spissu Y, Dedola S, Calia G, Puggioni G, Rocchitta G, Migheli R, Desole MS, Serra PA. Dual asymmetric-flow microdialysis for in vivo monitoring of brain neurochemicals. Talanta 2011; 85:1933-40. [PMID: 21872041 DOI: 10.1016/j.talanta.2011.07.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 06/21/2011] [Accepted: 07/07/2011] [Indexed: 01/25/2023]
Abstract
Microdialysis is an extensively used technique for both in vivo and in vitro experiments, applicable to animal and human studies. In neurosciences, the in vivo microdialysis is usually performed to follow changes in the extracellular levels of substances and to monitor neurotransmitters release in the brain of freely moving animals. Catecholamines, such as dopamine and their related compounds, are involved in the neurochemistry and in the physiology of mental diseases and neurological disorders. It is generally supposed that the brain's energy requirement is supplied by glucose oxidation. More recently, lactate was proposed to be the metabolic substrate used by neurons during synaptic activity. In our study, an innovative microdialysis approach for simultaneous monitoring of catecholamines, indolamines, glutamate and energy substrates in the striatum of freely moving rats, using an asymmetric perfusion flow rate on microdialysis probe, is described. As a result of this asymmetric perfusion, two samples are available from the same brain region, having the same analytes composition but different concentrations. The asymmetric flow perfusion could be a useful tool in neurosciences studies related to brain's energy requirement, such as toxin-induced models of Parkinson's disease.
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Affiliation(s)
- Gianfranco Bazzu
- Department of Neuroscience, Medical School, University of Sassari, Viale San Pietro 43/b, 07100 Sassari, Italy.
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Heni M, Hennige AM, Peter A, Siegel-Axel D, Ordelheide AM, Krebs N, Machicao F, Fritsche A, Häring HU, Staiger H. Insulin promotes glycogen storage and cell proliferation in primary human astrocytes. PLoS One 2011; 6:e21594. [PMID: 21738722 PMCID: PMC3124526 DOI: 10.1371/journal.pone.0021594] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 06/06/2011] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION In the human brain, there are at least as many astrocytes as neurons. Astrocytes are known to modulate neuronal function in several ways. Thus, they may also contribute to cerebral insulin actions. Therefore, we examined whether primary human astrocytes are insulin-responsive and whether their metabolic functions are affected by the hormone. METHODS Commercially available Normal Human Astrocytes were grown in the recommended medium. Major players in the insulin signaling pathway were detected by real-time RT-PCR and Western blotting. Phosphorylation events were detected by phospho-specific antibodies. Glucose uptake and glycogen synthesis were assessed using radio-labeled glucose. Glycogen content was assessed by histochemistry. Lactate levels were measured enzymatically. Cell proliferation was assessed by WST-1 assay. RESULTS We detected expression of key proteins for insulin signaling, such as insulin receptor β-subunit, insulin receptor substrat-1, Akt/protein kinase B and glycogen synthase kinase 3, in human astrocytes. Akt was phosphorylated and PI-3 kinase activity increased following insulin stimulation in a dose-dependent manner. Neither increased glucose uptake nor lactate secretion after insulin stimulation could be evidenced in this cell type. However, we found increased insulin-dependent glucose incorporation into glycogen. Furthermore, cell numbers increased dose-dependently upon insulin treatment. DISCUSSION This study demonstrated that human astrocytes are insulin-responsive at the molecular level. We identified glycogen synthesis and cell proliferation as biological responses of insulin signaling in these brain cells. Hence, this cell type may contribute to the effects of insulin in the human brain.
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Affiliation(s)
- Martin Heni
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Anita M. Hennige
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas Peter
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Dorothea Siegel-Axel
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Anna-Maria Ordelheide
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Norbert Krebs
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Fausto Machicao
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas Fritsche
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Hans-Ulrich Häring
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
- * E-mail:
| | - Harald Staiger
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Member of the German Center for Diabetes Research (DZD), Eberhard Karls University Tübingen, Tübingen, Germany
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Rostami E, Bellander BM. Monitoring of glucose in brain, adipose tissue, and peripheral blood in patients with traumatic brain injury: a microdialysis study. J Diabetes Sci Technol 2011; 5:596-604. [PMID: 21722575 PMCID: PMC3192626 DOI: 10.1177/193229681100500314] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Episodes of hyperglycemia are considered to be a secondary insult in traumatically brain-injured patients and have been shown to be associated with impaired outcome. Intensive insulin therapy to maintain a strict glucose level has been suggested to decrease morbidity and mortality in critically ill patients but this aggressive insulin treatment has been challenged. One aspect of strict glucose control is the risk of developing hypoglycemia. Extracellular intracerebral hypoglycemia monitored by intracerebral microdialysis has been shown to correlate with poor outcome. Monitoring of blood glucose during neurointensive care is important because adequate glucose supply from the systemic circulation is crucial to maintain the brain's glucose demand after brain injury. This study investigates the correlation of glucose levels in peripheral blood, subcutaneous (SC) fat, and extracellular intracerebral tissue in patients with severe traumatic brain injury during neurointensive care. METHODS In this study, we included 12 patients with severe traumatic brain injury. All patients received one microdialysis catheter each, with a membrane length of 10 mm (CMA 70, CMA Microdialysis AB) in the injured hemisphere of the brain and in the noninjured hemisphere of the brain. An additional microdialysis catheter with a membrane length of 30 mm (CMA 60, CMA Microdialysis AB) was placed in the periumbilical subcutaneous adipose tissue. We studied the correlation among levels of glucose measured in peripheral blood, adipose tissue, and the noninjured hemisphere of the brain during the first 12 hours and during 3 consecutive days in neurointensive care. RESULTS We found a significant positive correlation between levels of glucose in peripheral blood, SC fat, and the noninjured brain during the initial 12 hours but not in injured brain. However, the result varied between the patients during the 3-day measurements. In 7 patients, there was a significant positive correlation between glucose in blood and noninjured brain, while in 4 patients this correlation was poor. In 4 patients, there was a significant positive correlation in injured brain and blood. Furthermore, there was a significant correlation between brain and adipose tissue glucose during the 3-day measurements in 11 out of 12 patients. CONCLUSION This study indicates that there is a good correlation between blood glucose and adipose tissue during initial and later time points in the neurointensive care unit whereas the correlation between blood and brain seems to be more individualized among patients. This emphasizes the importance of using intracerebral microdialysis to ensure adequate intracerebral levels of glucose in patients suffering from severe traumatic brain injury and to detect hypoglycemia in the brain despite normal levels of blood glucose.
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Affiliation(s)
- Elham Rostami
- Department of Neuroscience, Karolinska University Hospital Solna, Karolinska Institute, Stockholm, Sweden.
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Metabonomic studies of schizophrenia and psychotropic medications: focus on alterations in CNS energy homeostasis. Bioanalysis 2011; 1:1615-26. [PMID: 21083107 DOI: 10.4155/bio.09.144] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Schizophrenia is a severe neuropsychiatric disorder with a poorly understood etiology and progression. We and other research groups have found that energy metabolic pathways in the CNS are perturbed in many subjects with this disorder. Antipsychotic drugs that generally target neurotransmission are currently used for clinical management of the disorder, although these can also have marked effects on energy metabolism in the CNS and periphery. Recent proteomic and metabonomic studies have shown that molecular pathways associated with brain energy metabolism are altered in both the disorder and by antipsychotic treatments. This review focuses on discussion of these molecular alterations. Increased knowledge in this area could facilitate biomarker identification and drug discovery based on improving brain energy metabolism in this debilitating disorder.
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Jiang Y, Zhao H, Lin Y, Zhu N, Ma Y, Mao L. Colorimetric detection of glucose in rat brain using gold nanoparticles. Angew Chem Int Ed Engl 2010; 49:4800-4. [PMID: 20533481 DOI: 10.1002/anie.201001057] [Citation(s) in RCA: 194] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Ying Jiang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100080, China
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Bazzu G, Puggioni GGM, Dedola S, Calia G, Rocchitta G, Migheli R, Desole MS, Lowry JP, O'Neill RD, Serra PA. Real-time monitoring of brain tissue oxygen using a miniaturized biotelemetric device implanted in freely moving rats. Anal Chem 2010; 81:2235-41. [PMID: 19222224 DOI: 10.1021/ac802390f] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A miniaturized biotelemetric device for the amperometric detection of brain tissue oxygen is presented. The new system, derived from a previous design, has been coupled with a carbon microsensor for the real-time detection of dissolved O(2) in the striatum of freely moving rats. The implantable device consists of a single-supply sensor driver, a current-to-voltage converter, a microcontroller, and a miniaturized data transmitter. The oxygen current is converted to a digital value by means of an analog-to-digital converter integrated in a peripheral interface controller (PIC). The digital data is sent to a personal computer using a six-byte packet protocol by means of a miniaturized 434 MHz amplitude modulation (AM) transmitter. The receiver unit is connected to a personal computer (PC) via a universal serial bus. Custom developed software allows the PC to store and plot received data. The electronics were calibrated and tested in vitro under different experimental conditions and exhibited high stability, low power consumption, and good linear response in the nanoampere current range. The in vivo results confirmed previously published observations on oxygen dynamics in the striatum of freely moving rats. The system serves as a rapid and reliable model for studying the effects of different drugs on brain oxygen and brain blood flow and it is suited to work with direct-reduction sensors or O(2)-consuming biosensors.
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Affiliation(s)
- Gianfranco Bazzu
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy
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Jiang Y, Zhao H, Lin Y, Zhu N, Ma Y, Mao L. Colorimetric Detection of Glucose in Rat Brain Using Gold Nanoparticles. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001057] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Cloutier M, Wellstead P. The control systems structures of energy metabolism. J R Soc Interface 2009; 7:651-65. [PMID: 19828503 DOI: 10.1098/rsif.2009.0371] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The biochemical regulation of energy metabolism (EM) allows cells to modulate their energetic output depending on available substrates and requirements. To this end, numerous biomolecular mechanisms exist that allow the sensing of the energetic state and corresponding adjustment of enzymatic reaction rates. This regulation is known to induce dynamic systems properties such as oscillations or perfect adaptation. Although the various mechanisms of energy regulation have been studied in detail from many angles at the experimental and theoretical levels, no framework is available for the systematic analysis of EM from a control systems perspective. In this study, we have used principles well known in control to clarify the basic system features that govern EM. The major result is a subdivision of the biomolecular mechanisms of energy regulation in terms of widely used engineering control mechanisms: proportional, integral, derivative control, and structures: feedback, cascade and feed-forward control. Evidence for each mechanism and structure is demonstrated and the implications for systems properties are shown through simulations. As the equivalence between biological systems and control components presented here is generic, it is also hypothesized that our work could eventually have an applicability that is much wider than the focus of the current study.
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Affiliation(s)
- Mathieu Cloutier
- Hamilton Institute, National University of Ireland, Maynooth, Ireland
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McLoughlin GA, Ma D, Tsang TM, Jones DNC, Cilia J, Hill MD, Robbins MJ, Benzel IM, Maycox PR, Holmes E, Bahn S. Analyzing the effects of psychotropic drugs on metabolite profiles in rat brain using 1H NMR spectroscopy. J Proteome Res 2009; 8:1943-52. [PMID: 19714815 DOI: 10.1021/pr800892u] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The mechanism of action of standard drug treatments for psychiatric disorders remains fundamentally unknown, despite intensive investigation in academia and the pharmaceutical industry. So far, little is known about the effects of psychotropic medications on brain metabolism in either humans or animals. In this study, we investigated the effects of a range of psychotropic drugs on rat brain metabolites. The drugs investigated were haloperidol, clozapine, olanzapine, risperidone, aripiprazole (antipsychotics); valproate, carbamazapine (mood stabilizers) and phenytoin (antiepileptic drug). The relative concentrations of endogenous metabolites were determined using high-resolution proton nuclear magnetic resonance (1H NMR) spectroscopy. The results revealed that different classes of psychotropic drugs modulated a range of metabolites, where each drug induced a distinct neurometabolic profile. Some common responses across several drugs or within a class of drug were also observed. Antipsychotic drugs and mood stabilizers, with the exception of olanzapine, consistently increased N-acetylaspartate (NAA) levels in at least one brain area, suggesting a common therapeutic response on increased neuronal viability. Most drugs also altered the levels of several metabolites associated with glucose metabolism, neurotransmission (including glutamate and aspartate) and inositols. The heterogenic pharmacological response reflects the functional and physiological diversity of the therapeutic interventions, including side effects. Further study of these metabolites in preclinical models should facilitate the development of novel drug treatments for psychiatric disorders with improved efficacy and side effect profiles.
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Affiliation(s)
- Gerard A McLoughlin
- Department of Biomolecular Medicine, Division of SORA, Faculty of Medicine, Imperial College, London SW7 2AZ, UK
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Heterogeneity of nervous system mitochondria: Location, location, location! Exp Neurol 2009; 218:293-307. [DOI: 10.1016/j.expneurol.2009.05.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2009] [Revised: 04/30/2009] [Accepted: 05/08/2009] [Indexed: 01/03/2023]
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Mangia S, Simpson IA, Vannucci SJ, Carruthers A. The in vivo neuron-to-astrocyte lactate shuttle in human brain: evidence from modeling of measured lactate levels during visual stimulation. J Neurochem 2009; 109 Suppl 1:55-62. [PMID: 19393009 DOI: 10.1111/j.1471-4159.2009.06003.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Functional magnetic resonance spectroscopy (fMRS) allows the non-invasive measurement of metabolite concentrations in the human brain, including changes induced by variations in neurotransmission activity. However, the limited spatial and temporal resolution of fMRS does not allow specific measurements of metabolites in different cell types. Thus, the analysis of fMRS data in the context of compartmentalized metabolism requires the formulation and application of mathematical models. In the present study we utilized the mathematical model introduced by Simpson et al. (2007) to gain insights into compartmentalized metabolism in vivo from the fMRS data obtained in humans at ultra high magnetic field by Mangia et al. (2007a). This model simulates brain glucose and lactate levels in a theoretical cortical slice. Using experimentally determined concentrations and catalytic activities for the respective transporter proteins, we calculate inflow and export of glucose and lactate in endothelium, astrocytes, and neurons. We then vary neuronal and astrocytic glucose and lactate utilization capacities until close correspondence is observed between in vivo and simulated glucose and lactate levels. The results of the simulations indicate that, when literature values of glucose transport capacity are utilized, the fMRS data are consistent with export of lactate by neurons and import of lactate by astrocytes, a mechanism that can be referred to as a neuron-to-astrocyte lactate shuttle. A shuttle of lactate from astrocytes to neurons could be simulated, but this required the astrocytic glucose transport capacity to be increased by 12-fold, and required that neurons not respond to activation with increased glycolysis, two conditions that are not supported by current literature.
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Affiliation(s)
- Silvia Mangia
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA.
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Calia G, Rocchitta G, Migheli R, Puggioni G, Spissu Y, Bazzu G, Mazzarello V, Lowry JP, O’Neill RD, Desole MS, Serra PA. Biotelemetric monitoring of brain neurochemistry in conscious rats using microsensors and biosensors. SENSORS 2009; 9:2511-23. [PMID: 22574029 PMCID: PMC3348796 DOI: 10.3390/s90402511] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 04/08/2009] [Accepted: 04/14/2009] [Indexed: 02/04/2023]
Abstract
In this study we present the real-time monitoring of three key brain neurochemical species in conscious rats using implantable amperometric electrodes interfaced to a biotelemetric device. The new system, derived from a previous design, was coupled with carbon-based microsensors and a platinum-based biosensor for the detection of ascorbic acid (AA), O2 and glucose in the striatum of untethered, freely-moving rats. The miniaturized device consisted of a single-supply sensor driver, a current-to-voltage converter, a microcontroller and a miniaturized data transmitter. The redox currents were digitized to digital values by means of an analog-to-digital converter integrated in a peripheral interface controller (PIC), and sent to a personal computer by means of a miniaturized AM transmitter. The electronics were calibrated and tested in vitro under different experimental conditions and exhibited high stability, low power consumption and good linear response in the nanoampere current range. The in-vivo results confirmed previously published observations on striatal AA, oxygen and glucose dynamics recorded in tethered rats. This approach, based on simple and inexpensive components, could be used as a rapid and reliable model for studying the effects of different drugs on brain neurochemical systems.
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Affiliation(s)
- Giammario Calia
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (G.C.); (G.R.); (R.M.); (G.P.); (Y.S.); (G.B.); (M.-S.D.)
| | - Gaia Rocchitta
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (G.C.); (G.R.); (R.M.); (G.P.); (Y.S.); (G.B.); (M.-S.D.)
| | - Rossana Migheli
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (G.C.); (G.R.); (R.M.); (G.P.); (Y.S.); (G.B.); (M.-S.D.)
| | - Giulia Puggioni
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (G.C.); (G.R.); (R.M.); (G.P.); (Y.S.); (G.B.); (M.-S.D.)
| | - Ylenia Spissu
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (G.C.); (G.R.); (R.M.); (G.P.); (Y.S.); (G.B.); (M.-S.D.)
| | - Gianfranco Bazzu
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (G.C.); (G.R.); (R.M.); (G.P.); (Y.S.); (G.B.); (M.-S.D.)
| | - Vittorio Mazzarello
- Department of Biomedical Sciences, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (V.M.)
| | - John P. Lowry
- Department of Chemistry, National University of Ireland, Maynooth, Co. Kildare, Ireland; E-Mail: (J.-P.L.)
| | - Robert D. O’Neill
- UCD School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland; E-Mail: (R.-D.O.)
| | - Maria S. Desole
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (G.C.); (G.R.); (R.M.); (G.P.); (Y.S.); (G.B.); (M.-S.D.)
| | - Pier A. Serra
- Department of Neuroscience, Medical School, University of Sassari, Viale S. Pietro 43/b, 07100 Sassari, Italy; E-Mails: (G.C.); (G.R.); (R.M.); (G.P.); (Y.S.); (G.B.); (M.-S.D.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel. +39-079-228558; Fax: +39-079-228525
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Karaszewski B, Wardlaw JM, Marshall I, Cvoro V, Wartolowska K, Haga K, Armitage PA, Bastin ME, Dennis MS. Early brain temperature elevation and anaerobic metabolism in human acute ischaemic stroke. Brain 2009; 132:955-64. [PMID: 19346327 DOI: 10.1093/brain/awp010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Early after acute ischaemic stroke, elevation of brain temperature might augment tissue metabolic rate and conversion of ischaemic but viable tissue to infarction. This might explain the observed link between pyrexia, severe stroke and poor outcome. We tested this hypothesis by measuring brain temperature and lactate concentration with multi-voxel magnetic resonance spectroscopic imaging across the acute ischaemic stroke lesion and normal brain as determined on diffusion imaging. We compared patterns of lactate concentration (reported in 'institutional units') and temperature elevation in diffusion lesion core, potential penumbra, ipsilateral and contralateral normal brain and with stroke severity. Amongst 40 patients with moderate to severe acute stroke imaged up to 26 h after onset, lactate concentration was highest in the ischaemic lesion core (42 versus 26 units in potential penumbra, P < 0.05), whereas temperature was highest in the potential penumbra (37.7 versus 37.3 degrees C in lesion core, P < 0.05). Neither sub-regional temperature nor lactate concentration correlated with stroke severity. With increasing time after stroke, ipsilateral brain temperature did not change, but contralateral hemisphere temperature was higher in patients scanned at later times; lactate remained elevated in the lesion core, but declined in potential penumbral and ipsilateral normal tissue at later times. We conclude that early brain temperature elevation after stroke is not directly related to lactate concentration, therefore augmented metabolism is unlikely to explain the relationship between early pyrexia, severe stroke and poor outcome. Early brain temperature elevation may result from different mechanisms to those which raise body temperature after stroke. Further studies are required to determine why early brain temperature elevation is highest in potential penumbral tissue.
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Affiliation(s)
- Bartosz Karaszewski
- Division of Clinical Neurosciences, University of Edinburgh, Western General Hospital, Crewe Rd, Edinburgh, EH4 2XU, UK
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Multimodal neuroimaging provides a highly consistent picture of energy metabolism, validating 31P MRS for measuring brain ATP synthesis. Proc Natl Acad Sci U S A 2009; 106:3988-93. [PMID: 19234118 DOI: 10.1073/pnas.0806516106] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neuroimaging methods have considerably developed over the last decades and offer various noninvasive approaches for measuring cerebral metabolic fluxes connected to energy metabolism, including PET and magnetic resonance spectroscopy (MRS). Among these methods, (31)P MRS has the particularity and advantage to directly measure cerebral ATP synthesis without injection of labeled precursor. However, this approach is methodologically challenging, and further validation studies are required to establish (31)P MRS as a robust method to measure brain energy synthesis. In the present study, we performed a multimodal imaging study based on the combination of 3 neuroimaging techniques, which allowed us to obtain an integrated picture of brain energy metabolism and, at the same time, to validate the saturation transfer (31)P MRS method as a quantitative measurement of brain ATP synthesis. A total of 29 imaging sessions were conducted to measure glucose consumption (CMRglc), TCA cycle flux (V(TCA)), and the rate of ATP synthesis (V(ATP)) in primate monkeys by using (18)F-FDG PET scan, indirect (13)C MRS, and saturation transfer (31)P MRS, respectively. These 3 complementary measurements were performed within the exact same area of the brain under identical physiological conditions, leading to: CMRglc = 0.27 +/- 0.07 micromol x g(-1) x min(-1), V(TCA) = 0.63 +/- 0.12 micromol x g(-1) x min(-1), and V(ATP) = 7.8 +/- 2.3 micromol x g(-1) x min(-1). The consistency of these 3 fluxes with literature and, more interestingly, one with each other, demonstrates the robustness of saturation transfer (31)P MRS for directly evaluating ATP synthesis in the living brain.
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