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Sanchez-Rangel E, Deajon-Jackson J, Hwang JJ. Pathophysiology and management of hypoglycemia in diabetes. Ann N Y Acad Sci 2022; 1518:25-46. [PMID: 36202764 DOI: 10.1111/nyas.14904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the century since the discovery of insulin, diabetes has changed from an early death sentence to a manageable chronic disease. This change in longevity and duration of diabetes coupled with significant advances in therapeutic options for patients has fundamentally changed the landscape of diabetes management, particularly in patients with type 1 diabetes mellitus. However, hypoglycemia remains a major barrier to achieving optimal glycemic control. Current understanding of the mechanisms of hypoglycemia has expanded to include not only counter-regulatory hormonal responses but also direct changes in brain glucose, fuel sensing, and utilization, as well as changes in neural networks that modulate behavior, mood, and cognition. Different strategies to prevent and treat hypoglycemia have been developed, including educational strategies, new insulin formulations, delivery devices, novel technologies, and pharmacologic targets. This review article will discuss current literature contributing to our understanding of the myriad of factors that lead to the development of clinically meaningful hypoglycemia and review established and novel therapies for the prevention and treatment of hypoglycemia.
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Affiliation(s)
- Elizabeth Sanchez-Rangel
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jelani Deajon-Jackson
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Janice Jin Hwang
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA.,Division of Endocrinology, Department of Internal Medicine, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, USA
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Cai M, Wang H, Song H, Yang R, Wang L, Xue X, Sun W, Hu J. Lactate Is Answerable for Brain Function and Treating Brain Diseases: Energy Substrates and Signal Molecule. Front Nutr 2022; 9:800901. [PMID: 35571940 PMCID: PMC9099001 DOI: 10.3389/fnut.2022.800901] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 03/18/2022] [Indexed: 11/13/2022] Open
Abstract
Research to date has provided novel insights into lactate's positive role in multiple brain functions and several brain diseases. Although notable controversies and discrepancies remain, the neurobiological role and the metabolic mechanisms of brain lactate have now been described. A theoretical framework on the relevance between lactate and brain function and brain diseases is presented. This review begins with the source and route of lactate formation in the brain and food; goes on to uncover the regulatory effect of lactate on brain function; and progresses to gathering the application and concentration variation of lactate in several brain diseases (diabetic encephalopathy, Alzheimer's disease, stroke, traumatic brain injury, and epilepsy) treatment. Finally, the dual role of lactate in the brain is discussed. This review highlights the biological effect of lactate, especially L-lactate, in brain function and disease studies and amplifies our understanding of past research.
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Affiliation(s)
- Ming Cai
- Department of Rehabilitation Medicine, Shanghai University of Medicine and Health Sciences Affiliated Zhoupu Hospital, Shanghai, China
- Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, China
| | - Hongbiao Wang
- Department of Physical Education, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Haihan Song
- Central Lab, Shanghai Pudong New Area People's Hospital, Shanghai, China
| | - Ruoyu Yang
- College of Rehabilitation Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Liyan Wang
- College of Rehabilitation Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Xiangli Xue
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Wanju Sun
- Central Lab, Shanghai Pudong New Area People's Hospital, Shanghai, China
- *Correspondence: Wanju Sun
| | - Jingyun Hu
- Central Lab, Shanghai Pudong New Area People's Hospital, Shanghai, China
- Jingyun Hu
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van Meijel LA, van Asten JJA, Grandjean J, Heerschap A, Tack CJ, van der Graaf M, Wiegers EC, de Galan BE. Effect of lactate administration on cerebral blood flow during hypoglycemia in people with type 1 diabetes. BMJ Open Diabetes Res Care 2022; 10:10/2/e002401. [PMID: 35321886 PMCID: PMC8943734 DOI: 10.1136/bmjdrc-2021-002401] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 02/22/2022] [Indexed: 11/11/2022] Open
Abstract
INTRODUCTION Impaired awareness of hypoglycemia, clinically reflected by the inability to timely detect hypoglycemia, affects approximately 25% of the people with type 1 diabetes. Both altered brain lactate handling and increased cerebral blood flow (CBF) during hypoglycemia appear to be involved in the pathogenesis of impaired awareness of hypoglycemia. Here we examine the effect of lactate on CBF during hypoglycemia. RESEARCH DESIGN AND METHODS Nine people with type 1 diabetes and normal awareness of hypoglycemia underwent two hyperinsulinemic euglycemic-hypoglycemic (3.0 mmol/L) glucose clamps in a 3T MR system, once with sodium lactate infusion and once with sodium chloride infusion. Global and regional changes in CBF were determined using pseudocontinuous arterial spin labeling. RESULTS Lactate (3.3±0.6 vs 0.9±0.2 mmol/L during lactate infusion vs placebo infusion, respectively) suppressed the counter-regulatory hormone responses to hypoglycemia. Global CBF increased considerably in response to intravenous lactate infusion but did not further increase during hypoglycemia. Lactate also blunted the hypoglycemia-induced regional redistribution of CBF towards the thalamus. CONCLUSIONS Elevated lactate levels enhance global CBF and blunt the thalamic CBF response during hypoglycemia in patients with type 1 diabetes, mimicking observations of impaired awareness of hypoglycemia. These findings suggest that alteration of CBF associated with lactate may play a role in some aspects of the development of impaired awareness of hypoglycemia. TRIAL REGISTRATION NUMBER NCT03730909.
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Affiliation(s)
- Lian A van Meijel
- Department of Internal Medicine, Radboudumc, Nijmegen, The Netherlands
- Department of Internal Medicine, Maxima Medical Centre, Veldhoven, The Netherlands
| | - Jack J A van Asten
- Department of Medical Imaging/Radiology, Radboudumc, Nijmegen, The Netherlands
| | - Joanes Grandjean
- Department of Medical Imaging/Radiology, Radboudumc, Nijmegen, The Netherlands
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboudumc, Nijmegen, The Netherlands
| | - Arend Heerschap
- Department of Medical Imaging/Radiology, Radboudumc, Nijmegen, The Netherlands
| | - Cornelis J Tack
- Department of Internal Medicine, Radboudumc, Nijmegen, The Netherlands
| | - Marinette van der Graaf
- Department of Medical Imaging/Radiology, Radboudumc, Nijmegen, The Netherlands
- Department of Pediatrics, Radboudumc, Nijmegen, The Netherlands
| | - Evita C Wiegers
- Department of Medical Imaging/Radiology, Radboudumc, Nijmegen, The Netherlands
- High Field MR Research Group, Department of Radiology, University Medical Center Utrecht Imaging Division, Utrecht, The Netherlands
| | - Bastiaan E de Galan
- Department of Internal Medicine, Radboudumc, Nijmegen, The Netherlands
- Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
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Lactate infusion as therapeutical intervention: a scoping review. Eur J Pediatr 2022; 181:2227-2235. [PMID: 35304646 PMCID: PMC9110504 DOI: 10.1007/s00431-022-04446-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/10/2022] [Accepted: 03/12/2022] [Indexed: 02/02/2023]
Abstract
UNLABELLED Traditionally, clinicians consider lactate as a waste product of anaerobic glycolysis. Interestingly, research has shown that lactate may serve as an alternative fuel for the brain to protect it against harm. The increasing scientific awareness of the potential beneficial side of lactate, however, is entering the clinic rather slowly. Following this, and realizing that the application of potential novel therapeutic strategies in pediatric populations often lags behind the development in adults, this review summarizes the key data on therapeutic use of intravenous infusion of sodium lactate in humans. PubMed and clinicaltrial.gov were searched up until November 2021 focusing on interventional studies in humans. Thirty-four articles were included in this review, with protocols of lactate infusion in adults with diabetes mellitus, traumatic brain injury, Alzheimer's disease, and cardiac disease. One study on lactate infusion in children was also included. Results of our literature search show that sodium lactate can be safely administrated, without major side effects. Additionally, the present literature clearly shows the potential benefits of therapeutic lactate infusion under certain pathological circumstances, including rather common clinical conditions like traumatic brain injury. CONCLUSION This review shows that lactate is a save, alternative energy source for the adult brain warranting studies on the potential therapeutic effects of sodium lactate infusion in children. WHAT IS KNOWN • Lactate is generally considered a waste product of anaerobic glycolysis. However, lactate also is an alternative fuel for different organs, including the brain. • Lactate infusion is not incorporated in standard care for any patient population. WHAT IS NEW • Thirty-four studies investigated the therapeutic use of intravenous sodium lactate in different patient populations, all with different study protocols. • Literature shows that lactate infusion may have beneficial effects in case of hypoglycemia, traumatic brain injury, and cardiac failure without the risk of major side effects.
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Park YW, Deelchand DK, Joers JM, Kumar A, Alvear AB, Moheet A, Seaquist ER, Öz G. Monitoring the Neurotransmitter Response to Glycemic Changes Using an Advanced Magnetic Resonance Spectroscopy Protocol at 7T. Front Neurol 2021; 12:698675. [PMID: 34484102 PMCID: PMC8416271 DOI: 10.3389/fneur.2021.698675] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/02/2021] [Indexed: 12/28/2022] Open
Abstract
The primary excitatory and inhibitory neurotransmitters glutamate (Glu) and gamma-aminobutyric acid (GABA) are thought to be involved in the response of the brain to changes in glycemia. Therefore, their reliable measurement is critical for understanding the dynamics of these responses. The concentrations of Glu and GABA, as well as glucose (Glc) in brain tissue, can be measured in vivo using proton (1H) magnetic resonance spectroscopy (MRS). Advanced MRS methodology at ultrahigh field allows reliable monitoring of these metabolites under changing metabolic states. However, the long acquisition times needed for these experiments while maintaining blood Glc levels at predetermined targets present many challenges. We present an advanced MRS acquisition protocol that combines commercial 7T hardware (Siemens Scanner and Nova Medical head coil), BaTiO3 dielectric padding, optical motion tracking, and dynamic frequency and B0 shim updates to ensure the acquisition of reproducibly high-quality data. Data were acquired with a semi-LASER sequence [repetition time/echo time (TR/TE) = 5,000/26 ms] from volumes of interest (VOIs) in the prefrontal cortex (PFC) and hypothalamus (HTL). Five healthy volunteers were scanned to evaluate the effect of the BaTiO3 pads on B 1 + distribution. Use of BaTiO3 padding resulted in a 60% gain in signal-to-noise ratio in the PFC VOI over the acquisition without the pad. The protocol was tested in six patients with type 1 diabetes during a clamp study where euglycemic (~100 mg/dL) and hypoglycemic (~50 mg/dL) blood Glc levels were maintained in the scanner. The new protocol allowed retention of all HTL data compared with our prior experience of having to exclude approximately half of the HTL data in similar clamp experiments in the 7T scanner due to subject motion. The advanced MRS protocol showed excellent data quality (reliable quantification of 11-12 metabolites) and stability (p > 0.05 for both signal-to-noise ratio and water linewidths) between euglycemia and hypoglycemia. Decreased brain Glc levels under hypoglycemia were reliably detected in both VOIs. In addition, mean Glu level trended lower at hypoglycemia than euglycemia for both VOIs, consistent with prior observations in the occipital cortex. This protocol will allow robust mechanistic investigations of the primary neurotransmitters, Glu and GABA, under changing glycemic conditions.
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Affiliation(s)
- Young Woo Park
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
| | - Dinesh K Deelchand
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
| | - James M Joers
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
| | - Anjali Kumar
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Alison Bunio Alvear
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Amir Moheet
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | | | - Gülin Öz
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
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Abstract
The endogenous timekeeping system evolved to anticipate the time of the day through the 24 hours cycle of the Earth's rotation. In mammals, the circadian clock governs rhythmic physiological and behavioral processes, including the daily oscillation in glucose metabolism, food intake, energy expenditure, and whole-body insulin sensitivity. The results from a series of studies have demonstrated that environmental or genetic alterations of the circadian cycle in humans and rodents are strongly associated with metabolic diseases such as obesity and type 2 diabetes. Emerging evidence suggests that astrocyte clocks have a crucial role in regulating molecular, physiological, and behavioral circadian rhythms such as glucose metabolism and insulin sensitivity. Given the concurrent high prevalence of type 2 diabetes and circadian disruption, understanding the mechanisms underlying glucose homeostasis regulation by the circadian clock and its dysregulation may improve glycemic control. In this review, we summarize the current knowledge on the tight interconnection between the timekeeping system, glucose homeostasis, and insulin sensitivity. We focus specifically on the involvement of astrocyte clocks, at the organism, cellular, and molecular levels, in the regulation of glucose metabolism.
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Affiliation(s)
- Olga Barca-Mayo
- Circadian and Glial Biology Lab, Physiology Department, Molecular Medicine and Chronic Diseases Research Centre (CiMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Miguel López
- NeurObesity Lab, Physiology Department, Molecular Medicine and Chronic Diseases Research Centre (CiMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
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Sejling AS, Wang P, Zhu W, Farhat R, Knight N, Appadurai D, Chan O. Repeated Activation of Noradrenergic Receptors in the Ventromedial Hypothalamus Suppresses the Response to Hypoglycemia. Endocrinology 2021; 162:6052997. [PMID: 33367607 PMCID: PMC7814298 DOI: 10.1210/endocr/bqaa241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 11/19/2022]
Abstract
Activation of the adrenergic system in response to hypoglycemia is important for proper recovery from low glucose levels. However, it has been suggested that repeated adrenergic stimulation may also contribute to counterregulatory failure, but the underlying mechanisms are not known. The aim of this study was to establish whether repeated activation of noradrenergic receptors in the ventromedial hypothalamus (VMH) contributes to blunting of the counterregulatory response by enhancing local lactate production. The VMH of nondiabetic rats were infused with either artificial extracellular fluid, norepinephrine (NE), or salbutamol for 3 hours/day for 3 consecutive days before they underwent a hypoglycemic clamp with microdialysis to monitor changes in VMH lactate levels. Repeated exposure to NE or salbutamol suppressed both the glucagon and epinephrine responses to hypoglycemia compared to controls. Furthermore, antecedent NE and salbutamol treatments raised extracellular lactate levels in the VMH. To determine whether the elevated lactate levels were responsible for impairing the hormone response, we pharmacologically inhibited neuronal lactate transport in a subgroup of NE-treated rats during the clamp. Blocking neuronal lactate utilization improved the counterregulatory hormone responses in NE-treated animals, suggesting that repeated activation of VMH β2-adrenergic receptors increases local lactate levels which in turn, suppresses the counterregulatory hormone response to hypoglycemia.
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Affiliation(s)
- Anne-Sophie Sejling
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Dyrehavevej, Denmark
- Current Affiliation: A.S. is currently with Novo Nordisk A/S
| | - Peili Wang
- Department of Internal Medicine-Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Wanling Zhu
- Department of Internal Medicine-Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Rawad Farhat
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Nicholas Knight
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Daniel Appadurai
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Owen Chan
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
- Correspondence: Dr. Owen Chan, PhD, University of Utah, Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, 15 North 2030 East, Rm 2420B, Salt Lake City, UT 84112, USA.
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8
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Joosten L, Boss M, Jansen T, Brom M, Buitinga M, Aarntzen E, Eriksson O, Johansson L, de Galan B, Gotthardt M. Molecular Imaging of Diabetes. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00041-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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9
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Zhang T, Zheng H, Fan K, Xia N, Li J, Yang C, Gao H, Yang Y. NMR-based metabolomics characterizes metabolic changes in different brain regions of streptozotocin-induced diabetic mice with cognitive decline. Metab Brain Dis 2020; 35:1165-1173. [PMID: 32643092 DOI: 10.1007/s11011-020-00598-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 07/01/2020] [Indexed: 02/06/2023]
Abstract
Diabetes at advanced age increases rise of cognitive impairment, but its potential mechanisms are still far from being fully understood. In this study, we analyzed the metabolic alterations in six different brain regions between streptozotocin (STZ)-induced diabetic mice with cognitive decline (DM) and age-matched controls (CON) using a 1H NMR-based metabolomics approach, to explore potential metabolic mechanisms underlying diabetes-induced cognitive decline. The results show that DM mice had a peculiar metabolic phenotype in all brain regions, mainly involving increased lactate level, decreased choline and energy metabolism as well as disrupted astrocyte-neuron metabolism. Furthermore, these metabolic changes exhibited a brain region-specific pattern. Collectively, our results suggest that brain region-specific metabolic disorders may be responsible for diabetes-induced cognitive dysfunction.
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Affiliation(s)
- Tingting Zhang
- Department of Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325035, China
| | - Hong Zheng
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China
| | - Kai Fan
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China
| | - Nengzhi Xia
- Department of Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325035, China
| | - Jiance Li
- Department of Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325035, China
| | - Changwei Yang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China
| | - Hongchang Gao
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China.
| | - Yunjun Yang
- Department of Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325035, China.
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Dong W, Moon SJ, Kelleher JK, Stephanopoulos G. Dissecting Mammalian Cell Metabolism through 13C- and 2H-Isotope Tracing: Interpretations at the Molecular and Systems Levels. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.9b05154] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Wentao Dong
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Sun Jin Moon
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Joanne K. Kelleher
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Gregory Stephanopoulos
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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11
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Richter J, Rabe D, Duysen K, Melchert UH, Oltmanns KM. Lactate infusion increases brain energy content during euglycemia but not hypoglycemia in healthy men. NMR IN BIOMEDICINE 2019; 32:e4167. [PMID: 31468650 DOI: 10.1002/nbm.4167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 07/04/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
A special characteristic of the brain is the usage of lactate as alternative fuel instead of glucose to preserve its energy homeostasis. This physiological function is valid for sufficient cerebral glucose supply, as well as presumably during hypoglycemia, given that exogenous lactate infusion suppresses hormonal counterregulation. However, it is not yet clarified whether this effect is mediated by the use of lactate as an alternative cerebral energy substrate or any other mechanism. We hypothesized that under conditions of limited access to glucose (ie, during experimental hypoglycemia) lactate infusion would prevent hypoglycemia-induced neuroenergetic deficits in a neuroprotective way. In a randomized, double-blind, crossover study, lactate vs placebo infusion was compared during hyperinsulinemic-hypoglycemic clamps in 16 healthy young men. We measured the cerebral high-energy phosphate content - ie, adenosine triphosphate (ATP), phosphocreatine (PCr) and inorganic phosphate (Pi) levels - by 31 P-magnetic resonance spectroscopy as well as the neuroendocrine stress response. During euglycemia, lactate infusion increased ATP/Pi as well as PCr/Pi ratios compared with baseline values and placebo infusion. During hypoglycemia, there were no differences between the lactate and the placebo condition in both ratios. Hormonal counterregulation was significantly diminished upon lactate infusion. Our data demonstrate an elevated cerebral high-energy phosphate content upon lactate infusion during euglycemia, whereas there was no such effect during experimental hypoglycemia. Nevertheless, lactate infusion suppressed hypoglycemic hormonal counterregulation. Lactate thus adds to cerebral energy provision during euglycemia and may contribute to an increase in ATP reserves, which in turn protects the brain against neuroglucopenia under recurrent hypopglycemic conditions, eg, in diabetic patients.
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Affiliation(s)
- Juliane Richter
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Doerte Rabe
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kai Duysen
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Uwe H Melchert
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kerstin M Oltmanns
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
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12
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Rothman DL, de Graaf RA, Hyder F, Mason GF, Behar KL, De Feyter HM. In vivo 13 C and 1 H-[ 13 C] MRS studies of neuroenergetics and neurotransmitter cycling, applications to neurological and psychiatric disease and brain cancer. NMR IN BIOMEDICINE 2019; 32:e4172. [PMID: 31478594 DOI: 10.1002/nbm.4172] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/30/2019] [Accepted: 05/07/2019] [Indexed: 06/10/2023]
Abstract
In the last 25 years 13 C MRS has been established as the only noninvasive method for measuring glutamate neurotransmission and cell specific neuroenergetics. Although technically and experimentally challenging 13 C MRS has already provided important new information on the relationship between neuroenergetics and neuronal function, the high energy cost of brain function in the resting state and the role of altered neuroenergetics and neurotransmitter cycling in disease. In this paper we review the metabolic and neurotransmitter pathways that can be measured by 13 C MRS and key findings on the linkage between neuroenergetics, neurotransmitter cycling, and brain function. Applications of 13 C MRS to neurological and psychiatric disease as well as brain cancer are reviewed. Recent technological developments that may help to overcome spatial resolution and brain coverage limitations of 13 C MRS are discussed.
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Affiliation(s)
- Douglas L Rothman
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Departments of Radiology and Biomedical Imaging, and Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, 300 Cedar Street, P.O. Box 208043, New Haven, CT, USA
| | - Robin A de Graaf
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Fahmeed Hyder
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Graeme F Mason
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kevin L Behar
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Henk M De Feyter
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
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13
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Wiegers EC, Rooijackers HM, Tack CJ, Philips BW, Heerschap A, van der Graaf M, de Galan BE. Effect of lactate administration on brain lactate levels during hypoglycemia in patients with type 1 diabetes. J Cereb Blood Flow Metab 2019; 39:1974-1982. [PMID: 29749805 PMCID: PMC6775588 DOI: 10.1177/0271678x18775884] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Administration of lactate during hypoglycemia suppresses symptoms and counterregulatory responses, as seen in patients with type 1 diabetes and impaired awareness of hypoglycemia (IAH), presumably because lactate can substitute for glucose as a brain fuel. Here, we examined whether lactate administration, in a dose sufficient to impair awareness of hypoglycemia, affects brain lactate levels in patients with normal awareness of hypoglycemia (NAH). Patients with NAH (n = 6) underwent two euglycemic-hypoglycemic clamps (2.8 mmol/L), once with sodium lactate infusion (NAH w|lac) and once with saline infusion (NAH w|placebo). Results were compared to those obtained during lactate administration in patients with IAH (n = 7) (IAH w|lac). Brain lactate levels were determined continuously with J-difference editing 1H-MRS. During lactate infusion, symptom and adrenaline responses to hypoglycemia were considerably suppressed in NAH. Infusion of lactate increased brain lactate levels modestly, but comparably, in both groups (mean increase in NAH w|lac: 0.12 ± 0.05 µmol/g and in IAH w|lac: 0.06 ± 0.04 µmol/g). The modest increase in brain lactate may suggest that the excess of lactate is immediately metabolized by the brain, which in turn may explain the suppressive effects of lactate on awareness of hypoglycemia observed in patients with NAH.
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Affiliation(s)
- Evita C Wiegers
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Hanne M Rooijackers
- Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Bart Wj Philips
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Marinette van der Graaf
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands.,Department of Pediatrics, Radboud university medical center, Nijmegen, The Netherlands
| | - Bastiaan E de Galan
- Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands
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14
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Wiegers EC, Rooijackers HM, van Asten JJA, Tack CJ, Heerschap A, de Galan BE, van der Graaf M. Elevated brain glutamate levels in type 1 diabetes: correlations with glycaemic control and age of disease onset but not with hypoglycaemia awareness status. Diabetologia 2019; 62:1065-1073. [PMID: 31001674 PMCID: PMC6509078 DOI: 10.1007/s00125-019-4862-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/04/2019] [Indexed: 12/27/2022]
Abstract
AIMS/HYPOTHESIS Chronic hyperglycaemia in type 1 diabetes affects the structure and functioning of the brain, but the impact of recurrent hypoglycaemia is unclear. Changes in the neurochemical profile have been linked to loss of neuronal function. We therefore aimed to investigate the impact of type 1 diabetes and burden of hypoglycaemia on brain metabolite levels, in which we assumed the burden to be high in individuals with impaired awareness of hypoglycaemia (IAH) and low in those with normal awareness of hypoglycaemia (NAH). METHODS We investigated 13 non-diabetic control participants, 18 individuals with type 1 diabetes and NAH and 13 individuals with type 1 diabetes and IAH. Brain metabolite levels were determined by analysing previously obtained 1H magnetic resonance spectroscopy data, measured under hyperinsulinaemic-euglycaemic conditions. RESULTS Brain glutamate levels were higher in participants with diabetes, both with NAH (+15%, p = 0.013) and with IAH (+19%, p = 0.003), compared with control participants. Cerebral glutamate levels correlated with HbA1c levels (r = 0.40; p = 0.03) and correlated inversely (r = -0.36; p = 0.04) with the age at diagnosis of diabetes. Other metabolite levels did not differ between groups, apart from an increase in aspartate in IAH. CONCLUSIONS/INTERPRETATION In conclusion, brain glutamate levels are elevated in people with type 1 diabetes and correlate with glycaemic control and age of disease diagnosis, but not with burden of hypoglycaemia as reflected by IAH. This suggests a potential role for glutamate as an early marker of hyperglycaemia-induced cerebral complications of type 1 diabetes. ClinicalTrials.gov NCT03286816; NCT02146404; NCT02308293.
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Affiliation(s)
- Evita C Wiegers
- Department of Radiology and Nuclear Medicine (766), Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands.
| | - Hanne M Rooijackers
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Jack J A van Asten
- Department of Radiology and Nuclear Medicine (766), Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine (766), Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Bastiaan E de Galan
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Marinette van der Graaf
- Department of Radiology and Nuclear Medicine (766), Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands
- Department of Pediatrics, Radboud university medical center, Nijmegen, the Netherlands
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15
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Farhat R, Su G, Sejling AS, Knight N, Fisher SJ, Chan O. Carvedilol prevents counterregulatory failure and impaired hypoglycaemia awareness in non-diabetic recurrently hypoglycaemic rats. Diabetologia 2019; 62:676-686. [PMID: 30627753 PMCID: PMC6403018 DOI: 10.1007/s00125-018-4802-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/28/2018] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS This study evaluates whether the non-selective β-blocker, carvedilol, can be used to prevent counterregulatory failure and the development of impaired awareness of hypoglycaemia (IAH) in recurrently hypoglycaemic rats. METHODS Sprague Dawley rats were implanted with vascular catheters and intracranial guide cannulas targeting the ventromedial hypothalamus (VMH). These animals underwent either three bouts of insulin-induced hypoglycaemia or received three saline injections (control group) over 3 days. A subgroup of recurrently hypoglycaemic animals was treated with carvedilol. The next day, the animals underwent a hypoglycaemic clamp with microdialysis without carvedilol treatment to evaluate changes in central lactate and hormone levels. To assess whether carvedilol prevented IAH, we treated rats that had received repeated 2-deoxyglucose (2DG) injections to impair their awareness of hypoglycaemia with carvedilol and measured food intake in response to insulin-induced hypoglycaemia as a surrogate marker for hypoglycaemia awareness. RESULTS Compared with the control group, recurrently hypoglycaemic rats had a ~1.7-fold increase in VMH lactate and this was associated with a 75% reduction in the sympathoadrenal response to hypoglycaemia. Treatment with carvedilol restored VMH lactate levels and improved the adrenaline (epinephrine) responses. In 2DG-treated rats compared with control animals receiving saline, food intake was reduced in response to hypoglycaemia and increased with carvedilol treatment. CONCLUSIONS/INTERPRETATION We conclude that carvedilol may be a useful therapy to prevent counterregulatory failure and improve IAH.
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Affiliation(s)
- Rawad Farhat
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA
| | - Gong Su
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA
- Beijing An Zhen Hospital, Capital Medical University, Beijing, China
| | | | - Nicholas Knight
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA
| | - Simon J Fisher
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA
| | - Owen Chan
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA.
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16
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Rehni AK, Dave KR. Impact of Hypoglycemia on Brain Metabolism During Diabetes. Mol Neurobiol 2018; 55:9075-9088. [PMID: 29637442 PMCID: PMC6179939 DOI: 10.1007/s12035-018-1044-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 03/27/2018] [Indexed: 12/24/2022]
Abstract
Diabetes is a metabolic disease afflicting millions of people worldwide. A substantial fraction of world's total healthcare expenditure is spent on treating diabetes. Hypoglycemia is a serious consequence of anti-diabetic drug therapy, because it induces metabolic alterations in the brain. Metabolic alterations are one of the central mechanisms mediating hypoglycemia-related functional changes in the brain. Acute, chronic, and/or recurrent hypoglycemia modulate multiple metabolic pathways, and exposure to hypoglycemia increases consumption of alternate respiratory substrates such as ketone bodies, glycogen, and monocarboxylates in the brain. The aim of this review is to discuss hypoglycemia-induced metabolic alterations in the brain in glucose counterregulation, uptake, utilization and metabolism, cellular respiration, amino acid and lipid metabolism, and the significance of other sources of energy. The present review summarizes information on hypoglycemia-induced metabolic changes in the brain of diabetic and non-diabetic subjects and the manner in which they may affect brain function.
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Affiliation(s)
- Ashish K Rehni
- Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
- Department of Neurology, University of Miami Miller School of Medicine, 1420 NW 9th Ave, NRB/203E, Miami, FL, 33136, USA
| | - Kunjan R Dave
- Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
- Department of Neurology, University of Miami Miller School of Medicine, 1420 NW 9th Ave, NRB/203E, Miami, FL, 33136, USA.
- Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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17
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Li W, Roy Choudhury G, Winters A, Prah J, Lin W, Liu R, Yang SH. Hyperglycemia Alters Astrocyte Metabolism and Inhibits Astrocyte Proliferation. Aging Dis 2018; 9:674-684. [PMID: 30090655 PMCID: PMC6065301 DOI: 10.14336/ad.2017.1208] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 12/08/2017] [Indexed: 12/01/2022] Open
Abstract
Diabetes milieu is a complex metabolic disease that has been known to associate with high risk of various neurological disorders. Hyperglycemia in diabetes could dramatically increase neuronal glucose levels which leads to neuronal damage, a phenomenon referred to as glucose neurotoxicity. On the other hand, the impact of hyperglycemia on astrocytes has been less explored. Astrocytes play important roles in brain energy metabolism through neuron-astrocyte coupling. As the component of blood brain barrier, glucose might be primarily transported into astrocytes, hence, impose direct impact on astrocyte metabolism and function. In the present study, we determined the effect of high glucose on the energy metabolism and function of primary astrocytes. Hyperglycemia level glucose (25 mM) induced cell cycle arrest and inhibited proliferation and migration of primary astrocytes. Consistently, high glucose decreased cyclin D1 and D3 expression. High glucose enhanced glycolytic metabolism, increased ATP and glycogen content in primary astrocytes. In addition, high glucose activated AMP-activated protein kinase (AMPK) signaling pathway in astrocytes. In summary, our in vitro study indicated that hyperglycemia might impact astrocyte energy metabolism and function phenotype. Our study provides a potential mechanism which may underlie the diabetic cerebral neuropathy and warrant further in vivo study to determine the effect of hyperglycemia on astrocyte metabolism and function.
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Affiliation(s)
- Wenjun Li
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Gourav Roy Choudhury
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Ali Winters
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Jude Prah
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Wenping Lin
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.,2Department of Orthopedic Surgery, The Second Affiliated Hospital, Fujian Medical University, Fujian Province, 362000, China
| | - Ran Liu
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Shao-Hua Yang
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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18
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Vilela VR, Antunes MM, Godoi VAF, Travassos PB, Souza HMD, Bazotte RB. Oral lactate intensifies insulin toxicity during severe insulin-induced hypoglycemia in mice. BRAZ J PHARM SCI 2018. [DOI: 10.1590/s2175-97902018000217617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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19
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Wiegers EC, Rooijackers HM, Tack CJ, Groenewoud HJMM, Heerschap A, de Galan BE, van der Graaf M. Effect of Exercise-Induced Lactate Elevation on Brain Lactate Levels During Hypoglycemia in Patients With Type 1 Diabetes and Impaired Awareness of Hypoglycemia. Diabetes 2017; 66:3105-3110. [PMID: 28935628 DOI: 10.2337/db17-0794] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/15/2017] [Indexed: 11/13/2022]
Abstract
Since altered brain lactate handling has been implicated in the development of impaired awareness of hypoglycemia (IAH) in type 1 diabetes, the capacity to transport lactate into the brain during hypoglycemia may be relevant in its pathogenesis. High-intensity interval training (HIIT) increases plasma lactate levels. We compared the effect of HIIT-induced hyperlacticacidemia on brain lactate during hypoglycemia between 1) patients with type 1 diabetes and IAH, 2) patients with type 1 diabetes and normal awareness of hypoglycemia, and 3) healthy participants without diabetes (n = 6 per group). All participants underwent a hypoglycemic (2.8 mmol/L) clamp after performing a bout of HIIT on a cycle ergometer. Before HIIT (baseline) and during hypoglycemia, brain lactate levels were determined continuously with J-difference-editing 1H-MRS, and time curves were analyzed using nonlinear mixed-effects modeling. At the beginning of hypoglycemia (after HIIT), brain lactate levels were elevated in all groups but most pronounced in patients with IAH. During hypoglycemia, brain lactate decreased ∼30% below baseline in patients with IAH but returned to baseline levels and remained there in the other two groups. Our results support the concept of enhanced lactate transport as well as increased lactate oxidation in patients with type 1 diabetes and IAH.
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Affiliation(s)
- Evita C Wiegers
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Hanne M Rooijackers
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Hans J M M Groenewoud
- Department for Health Evidence, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Bastiaan E de Galan
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marinette van der Graaf
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands
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Bonvento G, Valette J, Flament J, Mochel F, Brouillet E. Imaging and spectroscopic approaches to probe brain energy metabolism dysregulation in neurodegenerative diseases. J Cereb Blood Flow Metab 2017; 37:1927-1943. [PMID: 28276944 PMCID: PMC5464722 DOI: 10.1177/0271678x17697989] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/10/2017] [Accepted: 02/06/2017] [Indexed: 12/14/2022]
Abstract
Changes in energy metabolism are generally considered to play an important role in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's diseases. Whether these changes are causal or simply a part of self-defense mechanisms is a matter of debate. Furthermore, energy defects have often been discussed solely in the context of their probable neuronal origin without considering the cellular heterogeneity of the brain. Recent data point towards the existence of a tri-cellular compartmentation of brain energy metabolism between neurons, astrocytes, and oligodendrocytes, each cell type having a distinctive metabolic profile. Still, the number of methods to follow energy metabolism in patients is extremely limited and existing clinical techniques are blind to most cellular processes. There is a need to better understand how brain energy metabolism is regulated in health and disease through experiments conducted at different scales in animal models to implement new methods in the clinical setting. The purpose of this review is to offer a brief overview of the broad spectrum of methodological approaches that have emerged in recent years to probe energy metabolism in more detail. We conclude that multi-modal neuroimaging is needed to follow non-cell autonomous energy metabolism dysregulation in neurodegenerative diseases.
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Affiliation(s)
- Gilles Bonvento
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Julien Valette
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Julien Flament
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
- INSERM US 27, Molecular Imaging Research Center (MIRCen), Fontenay-aux-Roses, France
| | - Fanny Mochel
- INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Université Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, France
- Department of Genetics, AP-HP Hôpital Pitié-Salpêtrière, Paris, France
- University Pierre and Marie Curie, Neurometabolic Research Group, Paris, France
| | - Emmanuel Brouillet
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
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21
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Wiegers EC, Rooijackers HM, Tack CJ, Heerschap A, de Galan BE, van der Graaf M. Brain Lactate Concentration Falls in Response to Hypoglycemia in Patients With Type 1 Diabetes and Impaired Awareness of Hypoglycemia. Diabetes 2016; 65:1601-5. [PMID: 26993070 DOI: 10.2337/db16-0068] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/09/2016] [Indexed: 11/13/2022]
Abstract
Brain lactate may be involved in the development of impaired awareness of hypoglycemia (IAH), a condition that affects approximately 25% of patients with type 1 diabetes and increases the risk of severe hypoglycemia. The aim of this study was to investigate the effect of acute hypoglycemia on brain lactate concentration in patients with IAH as compared with those with normal awareness of hypoglycemia (NAH) and healthy control subjects (n = 7 per group). After an overnight fast, all subjects underwent a two-step hyperinsulinemic euglycemic (5.0 mmol/L)-hypoglycemic (2.8 mmol/L) glucose clamp. Brain lactate concentrations were measured continuously with (1)H-MRS using a specific lactate detection method. Hypoglycemia generated symptoms in patients with NAH and healthy control subjects but not in patients with IAH. Brain lactate fell significantly by ∼20% in response to hypoglycemia in patients with type 1 diabetes with IAH but remained stable in both healthy control subjects and in patients with NAH. The fall in brain lactate is compatible with increased brain lactate oxidation providing an alternative fuel source during hypoglycemia, which may contribute to the impaired detection of hypoglycemia.
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Affiliation(s)
- Evita C Wiegers
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Hanne M Rooijackers
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Bastiaan E de Galan
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Marinette van der Graaf
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, the Netherlands Department of Pediatrics, Radboud university medical center, Nijmegen, the Netherlands
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22
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De Feyter HM, Behar KL, Rao JU, Madden-Hennessey K, Ip KL, Hyder F, Drewes LR, Geschwind JF, de Graaf RA, Rothman DL. A ketogenic diet increases transport and oxidation of ketone bodies in RG2 and 9L gliomas without affecting tumor growth. Neuro Oncol 2016; 18:1079-87. [PMID: 27142056 DOI: 10.1093/neuonc/now088] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 03/28/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The dependence of tumor cells, particularly those originating in the brain, on glucose is the target of the ketogenic diet, which creates a plasma nutrient profile similar to fasting: increased levels of ketone bodies and reduced plasma glucose concentrations. The use of ketogenic diets has been of particular interest for therapy in brain tumors, which reportedly lack the ability to oxidize ketone bodies and therefore would be starved during ketosis. Because studies assessing the tumors' ability to oxidize ketone bodies are lacking, we investigated in vivo the extent of ketone body oxidation in 2 rodent glioma models. METHODS Ketone body oxidation was studied using (13)C MR spectroscopy in combination with infusion of a (13)C-labeled ketone body (beta-hydroxybutyrate) in RG2 and 9L glioma models. The level of ketone body oxidation was compared with nontumorous cortical brain tissue. RESULTS The level of (13)C-beta-hydroxybutyrate oxidation in 2 rat glioma models was similar to that of contralateral brain. In addition, when glioma-bearing animals were fed a ketogenic diet, the ketone body monocarboxylate transporter was upregulated, facilitating uptake and oxidation of ketone bodies in the gliomas. CONCLUSIONS These results demonstrate that rat gliomas can oxidize ketone bodies and indicate upregulation of ketone body transport when fed a ketogenic diet. Our findings contradict the hypothesis that brain tumors are metabolically inflexible and show the need for additional research on the use of ketogenic diets as therapy targeting brain tumor metabolism.
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Affiliation(s)
- Henk M De Feyter
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Kevin L Behar
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Jyotsna U Rao
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Kirby Madden-Hennessey
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Kevan L Ip
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Fahmeed Hyder
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Lester R Drewes
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Jean-François Geschwind
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Robin A de Graaf
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
| | - Douglas L Rothman
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (H.M.D.F., J.U.R., K.M.-H., K.L.I., J.-F.G., R.A.D., D.L.R.); Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut (K.L.B.); Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota (L.R.D.); Department of Biomedical Engineering, Yale University, New Haven, Connecticut (F.H., R.A.D., D.L.R.)
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Rooijackers HMM, Wiegers EC, Tack CJ, van der Graaf M, de Galan BE. Brain glucose metabolism during hypoglycemia in type 1 diabetes: insights from functional and metabolic neuroimaging studies. Cell Mol Life Sci 2016; 73:705-22. [PMID: 26521082 PMCID: PMC4735263 DOI: 10.1007/s00018-015-2079-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 12/30/2022]
Abstract
Hypoglycemia is the most frequent complication of insulin therapy in patients with type 1 diabetes. Since the brain is reliant on circulating glucose as its main source of energy, hypoglycemia poses a threat for normal brain function. Paradoxically, although hypoglycemia commonly induces immediate decline in cognitive function, long-lasting changes in brain structure and cognitive function are uncommon in patients with type 1 diabetes. In fact, recurrent hypoglycemia initiates a process of habituation that suppresses hormonal responses to and impairs awareness of subsequent hypoglycemia, which has been attributed to adaptations in the brain. These observations sparked great scientific interest into the brain's handling of glucose during (recurrent) hypoglycemia. Various neuroimaging techniques have been employed to study brain (glucose) metabolism, including PET, fMRI, MRS and ASL. This review discusses what is currently known about cerebral metabolism during hypoglycemia, and how findings obtained by functional and metabolic neuroimaging techniques contributed to this knowledge.
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Affiliation(s)
- Hanne M M Rooijackers
- Department of Internal Medicine 463, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Evita C Wiegers
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cees J Tack
- Department of Internal Medicine 463, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Marinette van der Graaf
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bastiaan E de Galan
- Department of Internal Medicine 463, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
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Glucose, Lactate, β-Hydroxybutyrate, Acetate, GABA, and Succinate as Substrates for Synthesis of Glutamate and GABA in the Glutamine-Glutamate/GABA Cycle. ADVANCES IN NEUROBIOLOGY 2016; 13:9-42. [PMID: 27885625 DOI: 10.1007/978-3-319-45096-4_2] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The glutamine-glutamate/GABA cycle is an astrocytic-neuronal pathway transferring precursors for transmitter glutamate and GABA from astrocytes to neurons. In addition, the cycle carries released transmitter back to astrocytes, where a minor fraction (~25 %) is degraded (requiring a similar amount of resynthesis) and the remainder returned to the neurons for reuse. The flux in the cycle is intense, amounting to the same value as neuronal glucose utilization rate or 75-80 % of total cortical glucose consumption. This glucose:glutamate ratio is reduced when high amounts of β-hydroxybutyrate are present, but β-hydroxybutyrate can at most replace 60 % of glucose during awake brain function. The cycle is initiated by α-ketoglutarate production in astrocytes and its conversion via glutamate to glutamine which is released. A crucial reaction in the cycle is metabolism of glutamine after its accumulation in neurons. In glutamatergic neurons all generated glutamate enters the mitochondria and its exit to the cytosol occurs in a process resembling the malate-aspartate shuttle and therefore requiring concomitant pyruvate metabolism. In GABAergic neurons one half enters the mitochondria, whereas the other one half is released directly from the cytosol. A revised concept is proposed for the synthesis and metabolism of vesicular and nonvesicular GABA. It includes the well-established neuronal GABA reuptake, its metabolism, and use for resynthesis of vesicular GABA. In contrast, mitochondrial glutamate is by transamination to α-ketoglutarate and subsequent retransamination to releasable glutamate essential for the transaminations occurring during metabolism of accumulated GABA and subsequent resynthesis of vesicular GABA.
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Klein MS, Shearer J. Metabolomics and Type 2 Diabetes: Translating Basic Research into Clinical Application. J Diabetes Res 2016; 2016:3898502. [PMID: 26636104 PMCID: PMC4655283 DOI: 10.1155/2016/3898502] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 03/11/2015] [Accepted: 03/25/2015] [Indexed: 01/14/2023] Open
Abstract
Type 2 diabetes (T2D) and its comorbidities have reached epidemic proportions, with more than half a billion cases expected by 2030. Metabolomics is a fairly new approach for studying metabolic changes connected to disease development and progression and for finding predictive biomarkers to enable early interventions, which are most effective against T2D and its comorbidities. In metabolomics, the abundance of a comprehensive set of small biomolecules (metabolites) is measured, thus giving insight into disease-related metabolic alterations. This review shall give an overview of basic metabolomics methods and will highlight current metabolomics research successes in the prediction and diagnosis of T2D. We summarized key metabolites changing in response to T2D. Despite large variations in predictive biomarkers, many studies have replicated elevated plasma levels of branched-chain amino acids and their derivatives, aromatic amino acids and α-hydroxybutyrate ahead of T2D manifestation. In contrast, glycine levels and lysophosphatidylcholine C18:2 are depressed in both predictive studies and with overt disease. The use of metabolomics for predicting T2D comorbidities is gaining momentum, as are our approaches for translating basic metabolomics research into clinical applications. As a result, metabolomics has the potential to enable informed decision-making in the realm of personalized medicine.
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Affiliation(s)
- Matthias S. Klein
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4
- *Matthias S. Klein:
| | - Jane Shearer
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4
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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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In Vivo NMR Studies of the Brain with Hereditary or Acquired Metabolic Disorders. Neurochem Res 2015; 40:2647-85. [PMID: 26610379 DOI: 10.1007/s11064-015-1772-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 11/10/2015] [Accepted: 11/12/2015] [Indexed: 01/09/2023]
Abstract
Metabolic disorders, whether hereditary or acquired, affect the brain, and abnormalities of the brain are related to cellular integrity; particularly in regard to neurons and astrocytes as well as interactions between them. Metabolic disturbances lead to alterations in cellular function as well as microscopic and macroscopic structural changes in the brain with diabetes, the most typical example of metabolic disorders, and a number of hereditary metabolic disorders. Alternatively, cellular dysfunction and degeneration of the brain lead to metabolic disturbances in hereditary neurological disorders with neurodegeneration. Nuclear magnetic resonance (NMR) techniques allow us to assess a range of pathophysiological changes of the brain in vivo. For example, magnetic resonance spectroscopy detects alterations in brain metabolism and energetics. Physiological magnetic resonance imaging (MRI) detects accompanying changes in cerebral blood flow related to neurovascular coupling. Diffusion and T1/T2-weighted MRI detect microscopic and macroscopic changes of the brain structure. This review summarizes current NMR findings of functional, physiological and biochemical alterations within a number of hereditary and acquired metabolic disorders in both animal models and humans. The global view of the impact of these metabolic disorders on the brain may be useful in identifying the unique and/or general patterns of abnormalities in the living brain related to the pathophysiology of the diseases, and identifying future fields of inquiry.
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Martín-Timón I, del Cañizo-Gómez FJ. Mechanisms of hypoglycemia unawareness and implications in diabetic patients. World J Diabetes 2015; 6:912-926. [PMID: 26185599 PMCID: PMC4499525 DOI: 10.4239/wjd.v6.i7.912] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 12/30/2014] [Accepted: 04/02/2015] [Indexed: 02/05/2023] Open
Abstract
Hypoglycemia unawareness (HU) is defined at the onset of neuroglycopenia before the appearance of autonomic warning symptoms. It is a major limitation to achieving tight diabetes and reduced quality of life. HU occurs in approximately 40% of people with type 1 diabetes mellitus (T1DM) and with less frequency in T2DM. Though the aetiology of HU is multifactorial, possible mechanisms include chronic exposure to low blood glucose, antecedent hypoglycaemia, recurrent severe hypoglycaemia and the failure of counter-regulatory hormones. Clinically it manifests as the inability to recognise impeding hypoglycaemia by symptoms, but the mechanisms and mediators remain largely unknown. Prevention and management of HU is complex, and can only be achieved by a multifactorial intervention of clinical care and structured patient education by the diabetes team. Less know regarding the impact of medications on the development or recognition of this condition in patients with diabetes. Several medications are thought to worsen or promote HU, whereas others may have an attenuating effect on the problem. This article reviews recent advances in how the brain senses and responds to hypoglycaemia, novel mechanisms by which people with insulin-treated diabetes develop HU and impaired counter-regulatory responses. The consequences that HU has on the person with diabetes and their family are also described. Finally, it examines the evidence for prevention and treatment of HU, and summarizes the effects of medications that may influence it.
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Salmina AB, Kuvacheva NV, Morgun AV, Komleva YK, Pozhilenkova EA, Lopatina OL, Gorina YV, Taranushenko TE, Petrova LL. Glycolysis-mediated control of blood-brain barrier development and function. Int J Biochem Cell Biol 2015; 64:174-84. [PMID: 25900038 DOI: 10.1016/j.biocel.2015.04.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 03/24/2015] [Accepted: 04/10/2015] [Indexed: 12/29/2022]
Abstract
The blood-brain barrier (BBB) consists of differentiated cells integrating in one ensemble to control transport processes between the central nervous system (CNS) and peripheral blood. Molecular organization of BBB affects the extracellular content and cell metabolism in the CNS. Developmental aspects of BBB attract much attention in recent years, and barriergenesis is currently recognized as a very important and complex mechanism of CNS development and maturation. Metabolic control of angiogenesis/barriergenesis may be provided by glucose utilization within the neurovascular unit (NVU). The role of glycolysis in the brain has been reconsidered recently, and it is recognized now not only as a process active in hypoxic conditions, but also as a mechanism affecting signal transduction, synaptic activity, and brain development. There is growing evidence that glycolysis-derived metabolites, particularly, lactate, affect barriergenesis and functioning of BBB. In the brain, lactate produced in astrocytes or endothelial cells can be transported to the extracellular space via monocarboxylate transporters (MCTs), and may act on the adjoining cells via specific lactate receptors. Astrocytes are one of the major sources of lactate production in the brain and significantly contribute to the regulation of BBB development and functioning. Active glycolysis in astrocytes is required for effective support of neuronal activity and angiogenesis, while endothelial cells regulate bioavailability of lactate for brain cells adjusting its bidirectional transport through the BBB. In this article, we review the current knowledge with regard to energy production in endothelial and astroglial cells within the NVU. In addition, we describe lactate-driven mechanisms and action of alternative products of glucose metabolism affecting BBB structural and functional integrity in developing and mature brain.
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Affiliation(s)
- Alla B Salmina
- Dept of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia; Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
| | - Natalia V Kuvacheva
- Dept of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia; Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
| | - Andrey V Morgun
- Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
| | - Yulia K Komleva
- Dept of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia; Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
| | - Elena A Pozhilenkova
- Dept of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia; Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
| | - Olga L Lopatina
- Dept of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia; Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
| | - Yana V Gorina
- Dept of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia; Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
| | - Tatyana E Taranushenko
- Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
| | - Lyudmila L Petrova
- Dept of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia; Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, P. Zheleznyaka Str. 1, Krasnoyarsk, 660022, Russia.
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Affiliation(s)
- Ana María Arbeláez
- Division of Endocrinology and Diabetes of the Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Philip E. Cryer
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
- Corresponding author: Philip E. Cryer,
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Chan O, Sherwin R. Influence of VMH fuel sensing on hypoglycemic responses. Trends Endocrinol Metab 2013; 24:616-24. [PMID: 24063974 PMCID: PMC3909530 DOI: 10.1016/j.tem.2013.08.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/20/2013] [Accepted: 08/27/2013] [Indexed: 12/12/2022]
Abstract
Hypoglycemia produces complex neural and hormonal responses that restore glucose levels to normal. Glucose, metabolic substrates and their transporters, neuropeptides and neurotransmitters alter the firing rate of glucose-sensing neurons in the ventromedial hypothalamus (VMH); these monitor energy status and regulate the release of neurotransmitters that instigate a suitable counter-regulatory response. Under normal physiological conditions, these mechanisms maintain blood glucose concentrations within narrow margins. However, antecedent hypoglycemia and diabetes can lead to adaptations within the brain that impair counter-regulatory responses. Clearly, the mechanisms employed to detect and regulate the response to hypoglycemia, and the pathophysiology of defective counter-regulation in diabetes, are complex and need to be elucidated to permit the development of therapies that prevent or reduce the risk of hypoglycemia.
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Affiliation(s)
- Owen Chan
- Yale University School of Medicine, Department of Internal Medicine - Section of Endocrinology, New Haven, CT, 06520 U.S.A
| | - Robert Sherwin
- Yale University School of Medicine, Department of Internal Medicine - Section of Endocrinology, New Haven, CT, 06520 U.S.A
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Gulanski BI, De Feyter HM, Page KA, Belfort-DeAguiar R, Mason GF, Rothman DL, Sherwin RS. Increased brain transport and metabolism of acetate in hypoglycemia unawareness. J Clin Endocrinol Metab 2013; 98:3811-20. [PMID: 23796565 PMCID: PMC4425818 DOI: 10.1210/jc.2013-1701] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
CONTEXT Intensive insulin therapy reduces the risk for long-term complications in patients with type 1 diabetes mellitus (T1DM) but increases the risk for hypoglycemia-associated autonomic failure (HAAF), a syndrome that includes hypoglycemia unawareness and defective glucose counterregulation (reduced epinephrine and glucagon responses to hypoglycemia). OBJECTIVE The objective of the study was to address mechanisms underlying HAAF, we investigated whether nonglucose fuels such as acetate, a monocarboxylic acid (MCA), can support cerebral energetics during hypoglycemia in T1DM individuals with hypoglycemia unawareness. DESIGN Magnetic resonance spectroscopy was used to measure brain transport and metabolism of [2-(13)C]acetate under hypoglycemic conditions. SETTING The study was conducted at the Yale Center for Clinical Investigation Hospital Research Unit, Yale Magnetic Resonance Research Center. PATIENTS AND OTHER PARTICIPANTS T1DM participants with moderate to severe hypoglycemia unawareness (n = 7), T1DM controls without hypoglycemia unawareness (n = 5), and healthy nondiabetic controls (n = 10) participated in the study. MAIN OUTCOME MEASURE(S) Brain acetate concentrations, (13)C percent enrichment of glutamine and glutamate, and absolute rates of acetate metabolism were measured. RESULTS Absolute rates of acetate metabolism in the cerebral cortex were 1.5-fold higher among T1DM/unaware participants compared with both control groups during hypoglycemia (P = .001). Epinephrine levels of T1DM/unaware subjects were significantly lower than both control groups (P < .05). Epinephrine levels were inversely correlated with levels of cerebral acetate use across the entire study population (P < .01), suggesting a relationship between up-regulated brain MCA use and HAAF. CONCLUSION Increased MCA transport and metabolism among T1DM individuals with hypoglycemia unawareness may be a mechanism to supply the brain with nonglucose fuels during episodes of acute hypoglycemia and may contribute to the syndrome of hypoglycemia unawareness, independent of diabetes.
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