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Shen XZ, Zhang YX, You QY. Case report of 18F-FDG PET/CT features of hypoglycemic encephalopathy. Medicine (Baltimore) 2023; 102:e34025. [PMID: 37327258 PMCID: PMC10270514 DOI: 10.1097/md.0000000000034025] [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: 04/07/2023] [Accepted: 05/26/2023] [Indexed: 06/18/2023] Open
Abstract
RATIONALE Hypoglycemia may cause diverse neurological manifestations, ranging from focal neurological deficits to irreversible coma. Severe and persistent hypoglycemia can lead to hypoglycemic encephalopathy (HE). Imaging findings of HE at different stages of 18F-FDG positron emission tomography/computed tomography (PET/CT) have rarely been reported. Herein, we describe a case of HE occurring in the medial frontal cortex, cerebellar cortex, and dentate nucleus using 18F-FDG PET/CT images from different periods. 18F-FDG PET/CT has a high value in displaying the lesion range and indicating the prognosis. PATIENT CONCERNS A 57-year-old male patient with type 2 diabetes (T2D) was transferred to the hospital with a history of unconsciousness for 1 night. The patient showed a significant decrease in blood glucose levels. DIAGNOSES The patient was initially diagnosed with a hypoglycemic coma. INTERVENTIONS The patient subsequently underwent a comprehensive treatment. The 18F-FDG PET/CT examination on the fifth day after admission revealed a significant symmetrical fluorodeoxyglucose (FDG)-positive accumulation in the bilateral medial frontal gyrus, cerebellar cortex, and dentate nucleus. A follow-up PET/CT examination 6 months later revealed hypometabolism in the bilateral medial frontal gyrus and no abnormalities in FDG uptake in the bilateral cerebellar cortex and dentate nucleus. OUTCOMES The patient condition was stable 6 months later, with a slow response, memory deterioration, occasional dizziness, and episodes of hypoglycemia. LESSONS HE lesions with a high metabolic status may be related to a metabolic compensation mechanism in response to gray matter loss. Some of the more severely damaged cells eventually die even after the blood sugar levels return to normal. Less damaged nerve cells can be recovered. 18F-FDG PET/CT has high value in indicating the lesion range and prognosis of HE.
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Affiliation(s)
- Xun-Ze Shen
- PET/CT Center, Shaoxing People’s Hospita, Shaoxing, Zhejiang Province, China
| | - Yan-Xing Zhang
- Department of Neurology, Shaoxing People’s Hospital, Shaoxing, Zhejiang Province, China
| | - Qiao-Ying You
- Department of Endocrinology, Shaoxing People’s Hospital, Shaoxing, Zhejiang Province, China
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2
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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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3
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Jacob P, Nwokolo M, Cordon SM, Macdonald IA, Zelaya FO, Amiel SA, O'Daly O, Choudhary P. Altered functional connectivity during hypoglycaemia in type 1 diabetes. J Cereb Blood Flow Metab 2022; 42:1451-1462. [PMID: 35209745 PMCID: PMC9274862 DOI: 10.1177/0271678x221082911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Behavioural responses to hypoglycaemia require coordinated recruitment of broadly distributed networks of interacting brain regions. We investigated hypoglycaemia-related changes in brain connectivity in people without diabetes (ND) and with type 1 diabetes with normal (NAH) or impaired (IAH) hypoglycaemia awareness. Two-step hyperinsulinaemic hypoglycaemic clamps were performed in 14 ND, 15 NAH and 22 IAH participants. BOLD timeseries were acquired at euglycaemia (5.0 mmol/L) and hypoglycaemia (2.6 mmol/L), with symptom and counter-regulatory hormone measurements. We investigated hypoglycaemia-related connectivity changes using established seed regions for the default mode (DMN), salience (SN) and central executive (CEN) networks and regions whose activity is modulated by hypoglycaemia: the thalamus and right inferior frontal gyrus (RIFG). Hypoglycaemia-induced changes in the DMN, SN and CEN were evident in NAH (all p < 0.05), with no changes in ND or IAH. However, in IAH there was a reduction in connectivity between regions within the RIFG (p = 0.001), not evident in the ND or NAH groups. We conclude that hypoglycaemia induces coordinated recruitment of the DMN and SN in diabetes with preserved hypoglycaemia awareness which is absent in IAH and ND. Changes in connectivity in the RIFG, a region associated with attentional modulation, may be key in impaired hypoglycaemia awareness.
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Affiliation(s)
- Peter Jacob
- Diabetes Research Group (Denmark Hill), Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Munachiso Nwokolo
- Diabetes Research Group (Denmark Hill), Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Sally M Cordon
- School of Life Sciences, MRC-ARUK Centre of Excellence in Musculoskeletal Ageing, Nottingham University Medical School, Queen's Medical Centre, Nottingham, UK
| | - Ian A Macdonald
- School of Life Sciences, MRC-ARUK Centre of Excellence in Musculoskeletal Ageing, Nottingham University Medical School, Queen's Medical Centre, Nottingham, UK
| | - Fernando O Zelaya
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Stephanie A Amiel
- Diabetes Research Group (Denmark Hill), Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Owen O'Daly
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Pratik Choudhary
- Diabetes Research Group (Denmark Hill), Faculty of Life Sciences and Medicine, King's College London, London, UK
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4
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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
Chronic metabolic diseases, including diabetes and obesity, have become a major global health threat of the twenty-first century. Maintaining glucose homeostasis is essential for survival in mammals. Complex and highly coordinated interactions between glucose-sensing mechanisms and multiple effector systems are essential for controlling glucose levels in the blood. The central nervous system (CNS) plays a crucial role in regulating glucose homeostasis. Growing evidence indicates that disruption of glucose sensing in selective CNS areas, such as the hypothalamus, is closely interlinked with the pathogenesis of obesity and type 2 diabetes mellitus. However, the underlying intracellular mechanisms of glucose sensing in the hypothalamus remain elusive. Here, we review the current literature on hypothalamic glucose-sensing mechanisms and discuss the impact of alterations of these mechanisms on the pathogenesis of diabetes.
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Affiliation(s)
- Nal Ae Yoon
- Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA
| | - Sabrina Diano
- Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA.
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Henriksen MM, Andersen HU, Thorsteinsson B, Pedersen-Bjergaard U. Effects of continuous glucose monitor-recorded nocturnal hypoglycaemia on quality of life and mood during daily life in type 1 diabetes. Diabetologia 2021; 64:903-913. [PMID: 33443591 DOI: 10.1007/s00125-020-05360-9] [Citation(s) in RCA: 8] [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: 05/06/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS The aim of this work was to assess the effect of spontaneous nocturnal hypoglycaemia on quality of life and mood during subsequent days in type 1 diabetes. METHODS A total of 153 people with type 1 diabetes participated in 6 days of blinded continuous glucose monitoring while documenting hypoglycaemic symptoms, quality of life and mood, daily. Hypoglycaemia was defined by interstitial glucose ≤3.9 mmol/l (IG3.9) and ≤ 3.0 mmol/l (IG3.0) for ≥15 min and was classified as asymptomatic if no hypoglycaemic symptoms were reported. RESULTS Self-estimated quality of life assessed by the EQ-5D VAS (but not by the WHO Well-Being Index) was higher the day after asymptomatic (but not after symptomatic) hypoglycaemic nights, as compared with non-hypoglycaemic nights (IG3.9, p = 0.021; IG3.0, p = 0.048). The effect increased with lower glucose nadir and longer duration of nocturnal hypoglycaemia (IG3.9, p = 0.03). The finding was confined to participants with impaired hypoglycaemia awareness. There was no effect of nocturnal hypoglycaemia on mood or self-estimated effectiveness at work the following day. CONCLUSIONS/INTERPRETATION Individuals with type 1 diabetes and impaired hypoglycaemia awareness reported higher quality of life on days preceded by nights with asymptomatic (but not symptomatic) hypoglycaemia. The effect was amplified by lower glucose nadir and longer duration of the episodes and may help explain resistance to implementation of interventions to reduce hypoglycaemia in many people with impaired hypoglycaemia awareness.
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Affiliation(s)
- Marie M Henriksen
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Hillerød, Denmark.
| | | | - Birger Thorsteinsson
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Hillerød, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ulrik Pedersen-Bjergaard
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Hillerød, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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7
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Zerbini G, Caminiti SP, Perani D. Hypoglycemia-induced brain hypometabolism captured in real time by FDG-PET. Eur J Nucl Med Mol Imaging 2021; 48:1686-1687. [PMID: 33398407 DOI: 10.1007/s00259-020-05141-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 11/29/2020] [Indexed: 11/26/2022]
Affiliation(s)
- Gianpaolo Zerbini
- Complications of Diabetes Unit, Diabetes Research Institute, IRCCS Ospedale San Raffaele, 20132, Milan, Italy
| | | | - Daniela Perani
- School of Psychology, Vita-Salute San Raffaele University, 20132, Milan, Italy.
- Nuclear Medicine Unit, San Raffaele Hospital, 20132, Milan, Italy.
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8
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Bednařík P, Henry PG, Khowaja A, Rubin N, Kumar A, Deelchand D, Eberly LE, Seaquist E, Öz G, Moheet A. Hippocampal Neurochemical Profile and Glucose Transport Kinetics in Patients With Type 1 Diabetes. J Clin Endocrinol Metab 2020; 105:5601935. [PMID: 31637440 PMCID: PMC7046023 DOI: 10.1210/clinem/dgz062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 09/27/2019] [Indexed: 01/28/2023]
Abstract
CONTEXT Longstanding type 1 diabetes (T1D) may lead to alterations in hippocampal neurochemical profile. Upregulation of hippocampal glucose transport as a result of recurrent exposure to hypoglycemia may preserve cognitive function during future hypoglycemia in subjects with T1D and impaired awareness of hypoglycemia (IAH). The effect of T1D on hippocampal neurochemical profile and glucose transport is unknown. OBJECTIVE To test the hypothesis that hippocampal neurochemical composition is altered in T1D and glucose transport is upregulated in T1D with IAH. DESIGN AND PARTICIPANTS Hippocampal neurochemical profile was measured with single-voxel magnetic resonance spectroscopy at 3T during euglycemia in 18 healthy controls (HC), 10 T1D with IAH, and 12 T1D with normal awareness to hypoglycemia (NAH). Additionally, 12 HC, 8 T1D-IAH, and 6 T1D-NAH were scanned during hyperglycemia to assess hippocampal glucose transport with metabolic modeling. SETTING University medical center. MAIN OUTCOME MEASURES Concentrations of hippocampal neurochemicals measured during euglycemia and ratios of maximal transport rate to cerebral metabolic rate of glucose (Tmax/CMRGlc), derived from magnetic resonance spectroscopy-measured hippocampal glucose as a function of plasma glucose. RESULTS Comparison of hippocampal neurochemical profile revealed no group differences (HC, T1D, T1D-IAH, and T1D-NAH). The ratio Tmax/CMRGlc was not significantly different between the groups, T1D-IAH (1.58 ± 0.09) and HC (1.65 ± 0.07, P = 0.54), between T1D-NAH (1.50 ± 0.09) and HC (P = 0.19), and between T1D-IAH and T1D-NAH (P = 0.53). CONCLUSIONS Subjects with T1D with sufficient exposure to recurrent hypoglycemia to create IAH did not have alteration of Tmax/CMRglc or neurochemical profile compared with participants with T1D-NAH or HC.
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Affiliation(s)
- Petr Bednařík
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Department of Imaging Methods, Faculty of Medicine, University of Ostrava, Ostrava, Czech Republic
| | - Pierre-Gilles Henry
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota
| | - Amir Khowaja
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Nathan Rubin
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota
| | - Anjali Kumar
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Dinesh Deelchand
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota
| | - Lynn E Eberly
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota
| | - Elizabeth Seaquist
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Gülin Öz
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota
| | - Amir Moheet
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
- Correspondence and Reprint Requests: Amir Moheet, MBBS, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, MMC 101, 420 Delaware St. SE, Minneapolis, MN 55455. E-mail:
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9
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Stanley S, Moheet A, Seaquist ER. Central Mechanisms of Glucose Sensing and Counterregulation in Defense of Hypoglycemia. Endocr Rev 2019; 40:768-788. [PMID: 30689785 PMCID: PMC6505456 DOI: 10.1210/er.2018-00226] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/17/2019] [Indexed: 12/12/2022]
Abstract
Glucose homeostasis requires an organism to rapidly respond to changes in plasma glucose concentrations. Iatrogenic hypoglycemia as a result of treatment with insulin or sulfonylureas is the most common cause of hypoglycemia in humans and is generally only seen in patients with diabetes who take these medications. The first response to a fall in glucose is the detection of impending hypoglycemia by hypoglycemia-detecting sensors, including glucose-sensing neurons in the hypothalamus and other regions. This detection is then linked to a series of neural and hormonal responses that serve to prevent the fall in blood glucose and restore euglycemia. In this review, we discuss the current state of knowledge about central glucose sensing and how detection of a fall in glucose leads to the stimulation of counterregulatory hormone and behavior responses. We also review how diabetes and recurrent hypoglycemia impact glucose sensing and counterregulation, leading to development of impaired awareness of hypoglycemia in diabetes.
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Affiliation(s)
- Sarah Stanley
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Amir Moheet
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Elizabeth R Seaquist
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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10
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Sehgal AA, Li Y, Lal B, Yadav NN, Xu X, Xu J, Laterra J, van Zijl PCM. CEST MRI of 3-O-methyl-D-glucose uptake and accumulation in brain tumors. Magn Reson Med 2018; 81:1993-2000. [PMID: 30206994 DOI: 10.1002/mrm.27489] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/11/2018] [Accepted: 07/17/2018] [Indexed: 01/02/2023]
Abstract
PURPOSE 3-O-Methyl-D-glucose (3-OMG) is a nonmetabolizable structural analog of glucose that offers potential to be used as a CEST-contrast agent for tumor detection. Here, we explore it for CEST-detection of malignant brain tumors and compare it with D-glucose. METHODS Glioma xenografts of a U87-MG cell line were implanted in five mice. Dynamic 3-OMG weighted images were collected using CEST-MRI at 11.7 T at a single offset of 1.2 ppm, showing the effect of accumulation of the contrast agent in the tumor, following an intravenous injection of 3-OMG (3 g/kg). RESULTS Tumor regions showed higher enhancement as compared to contralateral brain. The CEST contrast enhancement in the tumor region ranged from 2.5-5.0%, while it was 1.5-3.5% in contralateral brain. Previous D-glucose studies of the same tumor model showed an enhancement of 1.5-3.0% and 0.5-1.5% in tumor and contralateral brain, respectively. The signal gradually stabilized to a value that persisted for the length of the scan. CONCLUSIONS 3-OMG shows a CEST contrast enhancement that is approximately twice as much as that of D-glucose for a similar tumor line. In view of its suggested low toxicity and transport properties across the BBB, 3-OMG provides an option to be used as a nonmetallic contrast agent for evaluating brain tumors.
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Affiliation(s)
- Akansha Ashvani Sehgal
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Yuguo Li
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Bachchu Lal
- Department of Neurology, Oncology, and Neuroscience, The Johns Hopkins Medicine, and The Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
| | - Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Xiang Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - John Laterra
- Department of Neurology, Oncology, and Neuroscience, The Johns Hopkins Medicine, and The Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
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11
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Seaquist ER, Moheet A, Kumar A, Deelchand DK, Terpstra M, Kubisiak K, Eberly LE, Henry PG, Joers JM, Öz G. Hypothalamic Glucose Transport in Humans During Experimentally Induced Hypoglycemia-Associated Autonomic Failure. J Clin Endocrinol Metab 2017; 102:3571-3580. [PMID: 28911152 PMCID: PMC5587056 DOI: 10.1210/jc.2017-00477] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 07/17/2017] [Indexed: 01/15/2023]
Abstract
CONTEXT Upregulated brain glucose transport in response to recurrent hypoglycemia may contribute to the development of hypoglycemia-associated autonomic failure (HAAF) and impaired awareness of hypoglycemia. Whether recurrent hypoglycemia alters glucose transport in the hypothalamus is unknown. OBJECTIVE To test the hypothesis that hypothalamic glucose transport will increase in healthy volunteers preconditioned with recurrent hypoglycemia to induce HAAF. SETTING University medical center. DESIGN AND PARTICIPANTS Thirteen healthy subjects underwent paired euglycemic and hypoglycemic preconditioning studies separated by at least 1 month. Following preconditioning, hypothalamic glucose transport was measured by magnetic resonance spectroscopy (MRS) in the afternoon on day 2 of each preconditioning protocol. OUTCOME MEASURE The ratio of maximal transport rate to cerebral metabolic rate of glucose (Tmax/CMRglc), obtained from MRS-measured glucose in the hypothalamus as a function of plasma glucose. RESULTS HAAF was successfully induced based on lower epinephrine, glucagon, and cortisol during the third vs first hypoglycemic preconditioning clamp (P ≤ 0.01). Hypothalamic glucose transport was not different following recurrent euglycemia vs hypoglycemia (Tmax/CMRglc 1.62 ± 0.09 after euglycemia preconditioning and 1.75 ± 0.14 after hypoglycemia preconditioning; P was not significant). Hypothalamic glucose concentrations measured by MRS were not different following the two preconditioning protocols. CONCLUSIONS Glucose transport kinetics in the hypothalamus of healthy humans with experimentally induced HAAF were not different from those measured without HAAF. Future studies of patients with diabetes and impaired awareness of hypoglycemia will be necessary to determine if the existence of the diabetes state is required for this adaptation to hypoglycemia to occur.
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Affiliation(s)
- Elizabeth R. Seaquist
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455
| | - Amir Moheet
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455
| | - Anjali Kumar
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455
| | - Dinesh K. Deelchand
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455
| | - Melissa Terpstra
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455
| | - Kristine Kubisiak
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota 55455
| | - Lynn E. Eberly
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota 55455
| | - Pierre-Gilles Henry
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455
| | - James M. Joers
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455
| | - Gülin Öz
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota 55455
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12
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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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Zmyslowska A, Malkowski B, Fendler W, Borowiec M, Antosik K, Gnys P, Baranska D, Mlynarski W. Central nervous system PET-CT imaging reveals regional impairments in pediatric patients with Wolfram syndrome. PLoS One 2014; 9:e115605. [PMID: 25542043 PMCID: PMC4277290 DOI: 10.1371/journal.pone.0115605] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 12/01/2014] [Indexed: 11/18/2022] Open
Abstract
Wolfram syndrome (WFS) is inherited as an autosomal recessive disease with main clinical features of diabetes mellitus, optic atrophy, diabetes insipidus and deafness. However, various neurological defects may also be detected. The aim of this study was to evaluate aspects of brain structure and function using PET-CT (positron emission tomography and computed tomography) and MRI (magnetic resonance imaging) in pediatric patients with WFS. Regional changes in brain glucose metabolism were measured using standardized uptake values (SUVs) based on images of (18F) fluorodeoxyglucose (FDG) uptake in 7 WFS patients aged 10.1-16.0 years (mean 12.9±2.4) and in 20 healthy children aged 3-17.9 years (mean 12.8±4.1). In all patients the diagnosis of WFS was confirmed by DNA sequencing of the WFS1 gene. Hierarchical clustering showed remarkable similarities of glucose uptake patterns among WFS patients and their differences from the control group. SUV data were subsequently standardized for age groups <13 years old and>13 years old to account for developmental differences. Reduced SUVs in WFS patients as compared to the control group for the bilateral brain regions such as occipital lobe (-1.24±1.20 vs. -0.13±1.05; p = 0.028) and cerebellum (-1.11±0.69 vs. -0.204±1.00; p = 0.036) were observed and the same tendency for cingulate (-1.13±1.05 vs. -0.15±1.12; p = 0.056), temporal lobe (-1.10±0.98 vs. -0.15±1.10; p = 0.057), parietal lobe (-1.06±1.20 vs. -0.08±1.08; p = 0.058), central region (-1.01±1.04 vs. -0.09±1.06; p = 0.060), basal ganglia (-1.05±0.74 vs. -0.20±1.07; p = 0.066) and mesial temporal lobe (-1.06±0.82 vs. -0.26±1.08; p = 0.087) was also noticed. After adjusting for multiple hypothesis testing, the differences in glucose uptake were non-significant. For the first time, regional differences in brain glucose metabolism among patients with WFS were shown using PET-CT imaging.
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Affiliation(s)
- Agnieszka Zmyslowska
- Department of Pediatrics, Oncology, Hematology and Diabetology, Medical University of Lodz, Lodz, Poland
| | - Bogdan Malkowski
- Department of Nuclear Medicine, Oncology Center, Bydgoszcz, Poland
| | - Wojciech Fendler
- Department of Pediatrics, Oncology, Hematology and Diabetology, Medical University of Lodz, Lodz, Poland
| | - Maciej Borowiec
- Department of Clinical Genetics, Medical University of Lodz, Lodz, Poland
| | - Karolina Antosik
- Department of Clinical Genetics, Medical University of Lodz, Lodz, Poland
| | - Piotr Gnys
- Department of Pediatrics, Oncology, Hematology and Diabetology, Medical University of Lodz, Lodz, Poland
| | | | - Wojciech Mlynarski
- Department of Pediatrics, Oncology, Hematology and Diabetology, Medical University of Lodz, Lodz, Poland
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Heller S, Lawton J, Amiel S, Cooke D, Mansell P, Brennan A, Elliott J, Boote J, Emery C, Baird W, Basarir H, Beveridge S, Bond R, Campbell M, Chater T, Choudhary P, Clark M, de Zoysa N, Dixon S, Gianfrancesco C, Hopkins D, Jacques R, Kruger J, Moore S, Oliver L, Peasgood T, Rankin D, Roberts S, Rogers H, Taylor C, Thokala P, Thompson G, Ward C. Improving management of type 1 diabetes in the UK: the Dose Adjustment For Normal Eating (DAFNE) programme as a research test-bed. A mixed-method analysis of the barriers to and facilitators of successful diabetes self-management, a health economic analysis, a cluster randomised controlled trial of different models of delivery of an educational intervention and the potential of insulin pumps and additional educator input to improve outcomes. PROGRAMME GRANTS FOR APPLIED RESEARCH 2014. [DOI: 10.3310/pgfar02050] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BackgroundMany adults with type 1 diabetes cannot self-manage their diabetes effectively and die prematurely with diabetic complications as a result of poor glucose control. Following the positive results obtained from a randomised controlled trial (RCT) by the Dose Adjustment For Normal Eating (DAFNE) group, published in 2002, structured training is recommended for all adults with type 1 diabetes in the UK.AimWith evidence that blood glucose control is not always improved or sustained, we sought to determine factors explaining why some patients benefit from training more than other patients, identifying barriers to successful self-management, while developing other models to make skills training more accessible and effective.FindingsWe confirmed that glycaemic outcomes are not always improved or sustained when the DAFNE programme is delivered routinely, although improvements in psychosocial outcomes are maintained. DAFNE courses and follow-up support is needed to help participants instil and habituate key self-management practices such as regular diary/record keeping. DAFNE graduates need structured professional support following training. This is currently either unavailable or provided ad hoc without a supporting evidence base. Demographic and psychosocial characteristics had minimal explanatory power in predicting glycaemic control but good explanatory power in predicting diabetes-specific quality of life over the following year. We developed a DAFNE course delivered for 1 day per week over 5 weeks. There were no major differences in outcomes between this and a standard 1-week DAFNE course; in both arms of a RCT, glycaemic control improved by less than in the original DAFNE trial. We piloted a course delivering both the DAFNE programme and pump training. The pilot demonstrated the feasibility of a full multicentre RCT and resulted in us obtaining subsequent Health Technology Assessment programme funding. In collaboration with the National Institute for Health Research (NIHR) Diabetes Research Programme at King’s College Hospital (RG-PG-0606-1142), London, an intervention for patients with hypoglycaemic problems, DAFNE HART (Dose Adjustment for Normal Eating Hypoglycaemia Awareness Restoration Training), improved impaired hypoglycaemia awareness and is worthy of a formal trial. The health economic work developed a new type 1 diabetes model and confirmed that the DAFNE programme is cost-effective compared with no structured education; indeed, it is cost-saving in the majority of our analyses despite limited glycated haemoglobin benefit. Users made important contributions but this could have been maximised by involving them with grant writing, delaying training until the group was established and funding users’ time off work to maximise attendance. Collecting routine clinical data to conduct continuing evaluated roll-out is possible but to do this effectively requires additional administrator support and/or routine electronic data capture.ConclusionsWe propose that, in future work, we should modify the current DAFNE curricula to incorporate emerging understanding of behaviour change principles to instil and habituate key self-management behaviours that include key DAFNE competencies. An assessment of numeracy, critical for insulin dose adjustment, may help to determine whether or not additional input/support is required both before and after training. Models of structured support involving professionals should be developed and evaluated, incorporating technological interventions to help overcome the barriers identified above and enable participants to build effective self-management behaviours into their everyday lives.Trial registrationClinicalTrials.gov NCT01069393.FundingThe NIHR Programme Grants for Applied Research programme.
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Affiliation(s)
- Simon Heller
- Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Julia Lawton
- Centre for Population Health Sciences, University of Edinburgh, Edinburgh, UK
| | | | - Debbie Cooke
- Division of Psychology, University College London, London, UK
| | - Peter Mansell
- Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Alan Brennan
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Jackie Elliott
- Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Jonathan Boote
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
- Centre for Research into Primary and Community Care, University of Hertfordshire, Hatfield, UK
| | - Celia Emery
- Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Wendy Baird
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Hasan Basarir
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Susan Beveridge
- Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Rod Bond
- School of Psychology, University of Sussex, Brighton, UK
| | - Mike Campbell
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Timothy Chater
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | | | - Marie Clark
- Division of Psychology, University College London, London, UK
| | | | - Simon Dixon
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | | | | | - Richard Jacques
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Jen Kruger
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Susan Moore
- Northumbria Healthcare NHS Foundation Trust, North Shields, UK
| | - Lindsay Oliver
- Northumbria Healthcare NHS Foundation Trust, North Shields, UK
| | - Tessa Peasgood
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - David Rankin
- Centre for Population Health Sciences, University of Edinburgh, Edinburgh, UK
| | - Sue Roberts
- Northumbria Healthcare NHS Foundation Trust, North Shields, UK
| | | | - Carolin Taylor
- Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Praveen Thokala
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Gill Thompson
- Northumbria Healthcare NHS Foundation Trust, North Shields, UK
| | - Candice Ward
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
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Lagi A, Cencetti S, Lagi F. Incidence of hypoglycaemia associated with transient loss of consciousness. A retrospective cohort study. Int J Clin Pract 2014; 68:1029-33. [PMID: 24698543 DOI: 10.1111/ijcp.12426] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE To define the incidence of hypoglycaemia associated with transient loss of consciousness (TLoC). DESIGN Retrospective cohort study using a nested case-control analysis. SETTING Presentations to the emergency departments (EDs) of four general metropolitan hospitals in Azienda Sanitaria 10, Florence, Italy during 2012. PARTICIPANTS The cohort consisted of 133,285 patients extracted from the database of ED presentations. All patients with TLoC were identified by nurse triage, and their levels of glycaemia were recorded. Clinical investigations were undertaken using patients' charts and witness statements. Patients were matched with controls according to year of birth, year of cohort entry and gender. RESULTS Of the 133,285 patients, 3964 (2.9%) presented with TLoC, and 39 (1%) of the patients with TLoC had transient hypoglycaemia. Mean glycaemia in these 39 patients was 52 mg/dl (a level of 112 mg/dl was in controls). Symptoms associated with TLoC during hypoglycaemia differed from those characteristic of syncope. TLoC during hypoglycaemia mainly occurred in elderly patients with diabetes, who had relatively long disease duration, were receiving treatment, often also had renal failure and were experiencing symptoms as a result of lack of food intake. Together, these factors make it easier to diagnose hypoglycaemia associated with TLoC, and our results may prompt modification in medical practice. CONCLUSION Correct diagnosis of hypoglycaemia associated with TLoC has economic benefits if a protracted and costly series of clinical investigations can be avoided. A diagnosis of hypoglycaemia might also facilitate the resolution of patients' symptoms through lifestyle changes and adjustment of therapy.
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Affiliation(s)
- A Lagi
- Emergency Department & Syncope Unit, Ospedale Santa Maria Nuova, Firenze, Italia
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16
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Little SA, Leelarathna L, Barendse SM, Walkinshaw E, Tan HK, Lubina Solomon A, de Zoysa N, Rogers H, Choudhary P, Amiel SA, Heller SR, Evans M, Flanagan D, Speight J, Shaw JAM. Severe hypoglycaemia in type 1 diabetes mellitus: underlying drivers and potential strategies for successful prevention. Diabetes Metab Res Rev 2014; 30:175-90. [PMID: 24185859 DOI: 10.1002/dmrr.2492] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Revised: 10/23/2013] [Accepted: 10/25/2013] [Indexed: 02/03/2023]
Abstract
Hypoglycaemia remains an over-riding factor limiting optimal glycaemic control in type 1 diabetes. Severe hypoglycaemia is prevalent in almost half of those with long-duration diabetes and is one of the most feared diabetes-related complications. In this review, we present an overview of the increasing body of literature seeking to elucidate the underlying pathophysiology of severe hypoglycaemia and the limited evidence behind the strategies employed to prevent episodes. Drivers of severe hypoglycaemia including impaired counter-regulation, hypoglycaemia-associated autonomic failure, psychosocial and behavioural factors and neuroimaging correlates are discussed. Treatment strategies encompassing structured education, insulin analogue regimens, continuous subcutaneous insulin infusion pumps, continuous glucose sensing and beta-cell replacement therapies have been employed, yet there is little randomized controlled trial evidence demonstrating effectiveness of new technologies in reducing severe hypoglycaemia. Optimally designed interventional trials evaluating these existing technologies and using modern methods of teaching patients flexible insulin use within structured education programmes with the specific goal of preventing severe hypoglycaemia are required. Individuals at high risk need to be monitored with meticulous collection of data on awareness, as well as frequency and severity of all hypoglycaemic episodes.
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Affiliation(s)
- S A Little
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
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17
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Lawton J, Rankin D, Elliott J, Heller SR, Rogers HA, De Zoysa N, Amiel S. Experiences, views, and support needs of family members of people with hypoglycemia unawareness: interview study. Diabetes Care 2014; 37:109-15. [PMID: 23990515 DOI: 10.2337/dc13-1154] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Hypoglycemia unawareness (HU) affects ~25% of people with type 1 diabetes. People with HU are often reliant on family to detect hypoglycemia and treat severe episodes. We explored the impact of HU on family members' lives, their involvement in preventing and managing hypoglycemia, and their information and support needs. RESEARCH DESIGN AND METHODS This study employed an exploratory, qualitative design comprising in-depth interviews with 24 adult family members of persons with type 1 diabetes and HU. RESULTS Family members described restricting their lives so that they could help the person with HU detect and treat hypoglycemia. Some described being very physically afraid of their partner/relative when they had a hypoglycemic episode due to their aggressive and argumentative behavior and personality changes; this could also make treatment administration difficult. Family members also reported feeling anxious and worried about the safety of the person with HU, particularly when they were left unsupervised. These concerns were often precipitated by traumatic events, such as discovering the person with HU in a coma. Family members could neglect their own health and well-being to care for the person with HU and resentment could build up over time. Family members highlighted extensive, unmet needs for information and emotional support; however, some struggled to recognize and accept their own need for help. CONCLUSIONS Our findings reveal a caregiver group currently "in the shadow of the patient" and in urgent need of information and emotional support. Raising awareness among health care professionals is essential, and developing proactive support for family should be considered.
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18
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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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19
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De Feyter HM, Mason GF, Shulman GI, Rothman DL, Petersen KF. Increased brain lactate concentrations without increased lactate oxidation during hypoglycemia in type 1 diabetic individuals. Diabetes 2013; 62:3075-80. [PMID: 23715622 PMCID: PMC3749358 DOI: 10.2337/db13-0313] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Previous studies have reported that brain metabolism of acetate is increased more than twofold during hypoglycemia in type 1 diabetic (T1D) subjects with hypoglycemia unawareness. These data support the hypothesis that upregulation of blood-brain barrier monocarboxylic acid (MCA) transport may contribute to the maintenance of brain energetics during hypoglycemia in subjects with hypoglycemia unawareness. Plasma lactate concentrations are ∼10-fold higher than acetate concentrations, making lactate the most likely alternative MCA as brain fuel. We therefore examined transport of [3-(13)C]lactate across the blood-brain barrier and its metabolism in the brains of T1D patients and nondiabetic control subjects during a hypoglycemic clamp using (13)C magnetic resonance spectroscopy. Brain lactate concentrations were more than fivefold higher (P < 0.05) during hypoglycemia in the T1D subjects compared with the control subjects. Surprisingly, we observed no increase in the oxidation of blood-borne lactate in the T1D subjects, as reflected by similar (13)C fractional enrichments in brain glutamate and glutamine. Taken together, these data suggest that in addition to increased MCA transport at the blood-brain barrier, there may be additional metabolic adaptations that contribute to hypoglycemia unawareness in patients with T1D.
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Affiliation(s)
- Henk M. De Feyter
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
| | - Graeme F. Mason
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
| | - Douglas L. Rothman
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut
| | - Kitt Falk Petersen
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Corresponding author: Kitt Falk Petersen,
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20
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Affiliation(s)
- Philip E Cryer
- Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA.
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21
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Litvin M, Clark AL, Fisher SJ. Recurrent hypoglycemia: boosting the brain's metabolic flexibility. J Clin Invest 2013; 123:1922-4. [PMID: 23543052 DOI: 10.1172/jci69796] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
For people with diabetes, recurrent episodes of hypoglycemia limit the brain's ability to sense dangerously low blood sugar levels. In this issue of the JCI, the mechanisms behind this clinical problem of hypoglycemia unawareness are addressed by Herzog et al. The authors provide compelling evidence that recurrent hypoglycemia enhances transport of lactate into the brain and, although not itself a major alternative fuel source, lactate may preserve neuronal function during hypoglycemia by maintaining neuronal glucose metabolism. These findings redefine our understanding of the brain's metabolic adaptations that result from recurrent hypoglycemia.
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Affiliation(s)
- Marina Litvin
- Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, Washington University, St. Louis, Missouri 63110, USA
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22
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Gejl M, Lerche S, Egefjord L, Brock B, Møller N, Vang K, Rodell AB, Bibby BM, Holst JJ, Rungby J, Gjedde A. Glucagon-like peptide-1 (GLP-1) raises blood-brain glucose transfer capacity and hexokinase activity in human brain. FRONTIERS IN NEUROENERGETICS 2013; 5:2. [PMID: 23543638 PMCID: PMC3608902 DOI: 10.3389/fnene.2013.00002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/27/2013] [Indexed: 12/31/2022]
Abstract
In hyperglycemia, glucagon-like peptide-1 (GLP-1) lowers brain glucose concentration together with increased net blood-brain clearance and brain metabolism, but it is not known whether this effect depends on the prevailing plasma glucose (PG) concentration. In hypoglycemia, glucose depletion potentially impairs brain function. Here, we test the hypothesis that GLP-1 exacerbates the effect of hypoglycemia. To test the hypothesis, we determined glucose transport and consumption rates in seven healthy men in a randomized, double-blinded placebo-controlled cross-over experimental design. The acute effect of GLP-1 on glucose transfer in the brain was measured by positron emission tomography (PET) during a hypoglycemic clamp (3 mM plasma glucose) with (18)F-fluoro-2-deoxy-glucose (FDG) as tracer of glucose. In addition, we jointly analyzed cerebrometabolic effects of GLP-1 from the present hypoglycemia study and our previous hyperglycemia study to estimate the Michaelis-Menten constants of glucose transport and metabolism. The GLP-1 treatment lowered the vascular volume of brain tissue. Loading data from hypo- to hyperglycemia into the Michaelis-Menten equation, we found increased maximum phosphorylation velocity (V max) in the gray matter regions of cerebral cortex, thalamus, and cerebellum, as well as increased blood-brain glucose transport capacity (T max) in gray matter, white matter, cortex, thalamus, and cerebellum. In hypoglycemia, GLP-1 had no effects on net glucose metabolism, brain glucose concentration, or blood-brain glucose transport. Neither hexokinase nor transporter affinities varied significantly with treatment in any region. We conclude that GLP-1 changes blood-brain glucose transfer and brain glucose metabolic rates in a PG concentration-dependent manner. One consequence is that hypoglycemia eliminates these effects of GLP-1 on brain glucose homeostasis.
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Affiliation(s)
- Michael Gejl
- Department of Biomedicine - Pharmacology, Aarhus University Aarhus, Denmark
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23
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Reno CM, Litvin M, Clark AL, Fisher SJ. Defective counterregulation and hypoglycemia unawareness in diabetes: mechanisms and emerging treatments. Endocrinol Metab Clin North Am 2013; 42:15-38. [PMID: 23391237 PMCID: PMC3568263 DOI: 10.1016/j.ecl.2012.11.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
For people with diabetes, hypoglycemia remains the limiting factor in achieving glycemic control. This article reviews recent advances in how the brain senses and responds to hypoglycemia. Novel mechanisms by which individuals with insulin-treated diabetes develop hypoglycemia unawareness and impaired counterregulatory responses are outlined. Prevention strategies for reducing the incidence of hypoglycemia are discussed.
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Affiliation(s)
- Candace M. Reno
- Division of Endocrinology, Metabolism, & Lipid Research, Department of Medicine, Washington University, St. Louis, MO
| | - Marina Litvin
- Division of Endocrinology, Metabolism, & Lipid Research, Department of Medicine, Washington University, St. Louis, MO
| | - Amy L. Clark
- Division of Endocrinology and Diabetes, Department of Pediatrics, Washington University, St. Louis, MO
| | - Simon J. Fisher
- Division of Endocrinology, Metabolism, & Lipid Research, Department of Medicine, Washington University, St. Louis, MO
- Department of Cell Biology and Physiology, Washington University, St. Louis, MO
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24
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van de Ven KC, Tack CJ, Heerschap A, van der Graaf M, de Galan BE. Patients with type 1 diabetes exhibit altered cerebral metabolism during hypoglycemia. J Clin Invest 2013; 123:623-9. [PMID: 23298837 PMCID: PMC3561817 DOI: 10.1172/jci62742] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 11/08/2012] [Indexed: 01/24/2023] Open
Abstract
Patients with type 1 diabetes mellitus (T1DM) experience, on average, 2 to 3 hypoglycemic episodes per week. This study investigated the effect of hypoglycemia on cerebral glucose metabolism in patients with uncomplicated T1DM. For this purpose, hyperinsulinemic euglycemic and hypoglycemic glucose clamps were performed on separate days, using [1-13C]glucose infusion to increase plasma 13C enrichment. In vivo brain 13C magnetic resonance spectroscopy was used to measure the time course of 13C label incorporation into different metabolites and to calculate the tricarboxylic acid cycle flux (VTCA) by a one-compartment metabolic model. We found that cerebral glucose metabolism, as reflected by the VTCA, was not significantly different comparing euglycemic and hypoglycemic conditions in patients with T1DM. However, the VTCA was inversely related to the HbA1C and was, under hypoglycemic conditions, approximately 45% higher than that in a previously investigated group of healthy subjects. These data suggest that the brains of patients with T1DM are better able to endure moderate hypoglycemia than those of subjects without diabetes.
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Affiliation(s)
- Kim C.C. van de Ven
- Department of Radiology,
Department of General Internal Medicine, and
Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Cees J. Tack
- Department of Radiology,
Department of General Internal Medicine, and
Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Arend Heerschap
- Department of Radiology,
Department of General Internal Medicine, and
Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Marinette van der Graaf
- Department of Radiology,
Department of General Internal Medicine, and
Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Bastiaan E. de Galan
- Department of Radiology,
Department of General Internal Medicine, and
Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Gejl M, Egefjord L, Lerche S, Vang K, Bibby BM, Holst JJ, Mengel A, Møller N, Rungby J, Brock B, Gjedde A. Glucagon-like peptide-1 decreases intracerebral glucose content by activating hexokinase and changing glucose clearance during hyperglycemia. J Cereb Blood Flow Metab 2012; 32:2146-52. [PMID: 22929437 PMCID: PMC3519409 DOI: 10.1038/jcbfm.2012.118] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Type 2 diabetes and hyperglycemia with the resulting increase of glucose concentrations in the brain impair the outcome of ischemic stroke, and may increase the risk of developing Alzheimer's disease (AD). Reports indicate that glucagon-like peptide-1 (GLP-1) may be neuroprotective in models of AD and stroke: Although the mechanism is unclear, glucose homeostasis appears to be important. We conducted a randomized, double-blinded, placebo-controlled crossover study in nine healthy males. Positron emission tomography was used to determine the effect of GLP-1 on cerebral glucose transport and metabolism during a hyperglycemic clamp with (18)fluoro-deoxy-glucose as tracer. Glucagon-like peptide-1 lowered brain glucose (P=0.023) in all regions. The cerebral metabolic rate for glucose was increased everywhere (P=0.039) but not to the same extent in all regions (P=0.022). The unidirectional glucose transfer across the blood-brain barrier remained unchanged (P=0.099) in all regions, while the unidirectional clearance and the phosphorylation rate increased (P=0.013 and 0.017), leading to increased net clearance of the glucose tracer (P=0.006). We show that GLP-1 plays a role in a regulatory mechanism involved in the actions of GLUT1 and glucose metabolism: GLP-1 ensures less fluctuation of brain glucose levels in response to alterations in plasma glucose, which may prove to be neuroprotective during hyperglycemia.
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Affiliation(s)
- Michael Gejl
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Hypoglycemia-induced increases in thalamic cerebral blood flow are blunted in subjects with type 1 diabetes and hypoglycemia unawareness. J Cereb Blood Flow Metab 2012; 32:2084-90. [PMID: 22892724 PMCID: PMC3494000 DOI: 10.1038/jcbfm.2012.117] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The thalamus has been found to be activated during the early phase of moderate hypoglycemia. Here, we tested the hypothesis that this region is less activated during hypoglycemia in subjects with type 1 diabetes (T1DM) and hypoglycemia unawareness relative to controls. Twelve controls (5 F/7 M, age 40 ± 14 years, body mass index 24.2 ± 2.7 kg/m(2)) and eleven patients (7 F/4 M, age 39 ± 13 years, body mass index 26.5 ± 4.4 kg/m(2)) with well-controlled T1DM (A1c 6.8 ± 0.4%) underwent a two-step hyperinsulinemic (2.0 mU/kg per minute) clamp. Cerebral blood flow (CBF) weighted images were acquired using arterial spin labeling to monitor cerebral activation in the midbrain regions. Blood glucose was first held at 95 mg/dL and then allowed to decrease to 50 mg/dL. The CBF image acquisition during euglycemia and hypoglycemia began within a few minutes of when the target blood glucose values were reached. Hypoglycemia unaware T1DM subjects displayed blunting of the physiologic CBF increase that occurs in the thalamus of healthy individuals during the early phase of moderate hypoglycemia. A positive correlation was observed between thalamic response and epinephrine response to hypoglycemia, suggesting that this region may be involved in the coordination of the counter regulatory response to hypoglycemia.
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Abstract
Functional neuroimaging techniques can be used to study changes in regional brain activation, using changes in surrogate markers such as regional cerebral perfusion and rates of glucose uptake or metabolism. These approaches are shedding new light on two major health problems: the increasing burden of type 2 diabetes mellitus (T2DM), which is driven by the rising prevalence of insulin resistance and obesity; and recurrent intractable problematic hypoglycaemia, which is driven by the cognitive impairment that can occur in association with iatrogenic hypoglycaemic episodes. Some patients with diabetes mellitus lose awareness of being hypoglycaemic, which puts them at risk of severe hypoglycaemia as they are unlikely to take action to prevent the condition worsening. Involvement of corticolimbic brain and centres serving higher executive functions as well as the hypothalamus has been demonstrated in both situations and has implications for therapy. This Review describes the relevant principles of functional neuroimaging techniques and presents data supporting the notion that the dysregulation of central pathways involved in metabolic regulation, reward and appetite could contribute to problematic hypoglycaemia during therapy for diabetes mellitus and to insulin-resistant obesity and T2DM. Understanding these dysregulations could enable the development of novel clinical interventions.
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Affiliation(s)
- Yee-Seun Cheah
- Diabetes Research Group, Weston Education Centre, Denmark Hill Campus, King's College London, 10 Cutcombe Road, London SE5 9RJ, UK
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van de Ven KC, van der Graaf M, Tack CJ, Heerschap A, de Galan BE. Steady-state brain glucose concentrations during hypoglycemia in healthy humans and patients with type 1 diabetes. Diabetes 2012; 61:1974-7. [PMID: 22688331 PMCID: PMC3402320 DOI: 10.2337/db11-1778] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The objective of this study was to investigate the relationship between plasma and brain glucose levels during euglycemia and hypoglycemia in healthy subjects and patients with type 1 diabetes mellitus (T1DM). Hyperinsulinemic euglycemic (5 mmol/L) and hypoglycemic (3 mmol/L) [1-(13)C]glucose clamps were performed in eight healthy subjects and nine patients with uncomplicated T1DM (HbA(1c) 7.7 ± 1.4%). Brain glucose levels were measured by (13)C magnetic resonance spectroscopy. Linear regression analysis was used to fit the relationship between plasma and brain glucose levels and calculate reversible Michaelis-Menten (MM) kinetic parameters. Brain glucose values during euglycemia (1.1 ± 0.4 μmol/g vs. 1.1 ± 0.3 μmol/g; P = 0.95) and hypoglycemia (0.5 ± 0.2 μmol/g vs. 0.6 ± 0.3 μmol/g; P = 0.52) were comparable between healthy subjects and T1DM patients. MM kinetic parameters of combined data were calculated to be maximum transport rate/cerebral metabolic rate of glucose (T(max)/CMR(glc)) = 2.25 ± 0.32 and substrate concentration at half maximal transport (K(t)) = 1.53 ± 0.88 mmol/L, which is in line with previously published data obtained under hyperglycemic conditions. In conclusion, the linear MM relationship between plasma and brain glucose can be extended to low plasma glucose levels. We found no evidence that the plasma to brain glucose relationship or the kinetics describing glucose transport over the blood-brain barrier differ between healthy subjects and patients with uncomplicated, reasonably well-controlled T1DM.
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Affiliation(s)
- Kim C.C. van de Ven
- Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Marinette van der Graaf
- Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
- Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Cees J. Tack
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Arend Heerschap
- Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Bastiaan E. de Galan
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
- Corresponding author: Bastiaan E. de Galan,
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Rogers HA, de Zoysa N, Amiel SA. Patient experience of hypoglycaemia unawareness in Type 1 diabetes: are patients appropriately concerned? Diabet Med 2012; 29:321-7. [PMID: 21913969 DOI: 10.1111/j.1464-5491.2011.03444.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Risk of severe hypoglycaemia is increased by absence of subjective awareness of hypoglycaemia and reduced by avoidance of minor hypoglycaemia. For many, problems persist despite educational strategies that work for others. We explored psychological factors that might inhibit the efforts of an individual in hypoglycaemia avoidance. METHODS People with Type 1 diabetes and hypoglycaemia unawareness gave semi-structured interviews exploring their perceptions and experiences of their condition. Identified factors were grouped into categories and analysed to establish links and form a grounded theory in a constant comparative analysis. A questionnaire was devised from the qualitative analysis to identify patients with problematic beliefs about their hypoglycaemia. RESULTS Saturation (no new themes emerging) was reached with 17 patients. Responses fell into two groups: high concern and low concern regarding hypoglycaemia unawareness. Those in the first group described severe hypoglycaemia as aversive and wanted to regain awareness. The second group included three patients in whom unawareness was not associated with severe hypoglycaemia, nevertheless unhelpful attitudes which inhibited hypoglycaemia avoidance were expressed. Responses from this group fell into categories: (1) normalizing the presence of unawareness; (2) underestimating its consequences; (3) wanting to avoiding the 'sick role'; and (4) overestimating the consequences of hyperglycaemia. CONCLUSIONS A qualitative analysis of patient interviews identified deficits in education, technology and motivation in hypoglycaemia unawareness. Interventions can therefore be tailored to target underlying problems that prevent individual patients from regaining awareness. A brief assessment tool was devised to categorize patients' hypoglycaemia unawareness accordingly. Psychological interventions should be developed to address the problems of 'low concern' regarding hypoglycaemia unawareness.
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Affiliation(s)
- H A Rogers
- Diabetes Research Group, King's College London, London, UK.
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Impaired hippocampal glucoregulation in the cannabinoid CB1 receptor knockout mice as revealed by an optimized in vitro experimental approach. J Neurosci Methods 2011; 204:366-73. [PMID: 22155442 DOI: 10.1016/j.jneumeth.2011.11.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 11/28/2011] [Accepted: 11/28/2011] [Indexed: 11/21/2022]
Abstract
Several techniques exist to study the rate of glucose uptake and metabolism in the brain but most of them are not sufficiently robust to permit extensive pharmacological analysis. Here we optimized an in vitro measurement of the simultaneous accumulation of the metabolizable and non-metabolizable (3)H and (14)C d-glucose analogues; permitting convenient large-scale studies on glucose uptake and metabolism in brain slices. Next, we performed an extensive pharmacological characterization on the putative glucoregulator role of the endocannabinoid system in the hippocampal slices of the rat, and the wild-type and the CB(1) cannabinoid receptor (CB(1)R) knockout mice. We observed that (3)H-3-O-methylglucose is a poor substrate to measure glucose uptake in the hippocampus. (3)H-2-deoxyglucose is a better substrate but its uptake is still lower than that of (14)C-U-d-glucose, from which the slices constantly metabolize and dissipate (14)C atoms. Thus, uptake and the metabolism values are not to be used as standalones but as differences between a control and a treatment. The CB(1)R knockout mice exhibited ∼10% less glucose uptake and glucose carbon atom dissipation in comparison with the wild-type mice. This may represent congenital defects as acute treatments of the rat and mouse slices with cannabinoid agonists, antagonists and inhibitors of endocannabinoid uptake/metabolism failed to induce robust changes in either the uptake or the metabolism of glucose. In summary, we report here an optimized technique ideal to complement other metabolic approaches of high spatiotemporal resolution. This technique allowed us concluding that CB(1)Rs are at least indirectly involved in hippocampal glucoregulation.
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Abstract
Iatrogenic hypoglycemia is the limiting factor in the glycemic control of diabetes. It causes recurrent symptomatic and sometimes, at least temporally, disabling episodes in most people with type 1 diabetes, as well as in many with advanced type 2 diabetes. Furthermore, iatrogenic hypoglycemia precludes maintenance of euglycemia during the lifetime of a person with diabetes and thus full realization of the well established benefits of glycemic control. In this article I discuss the clinical problem of hypoglycemia in diabetes from the perspective of pathophysiology. First, the syndromes of defective glucose counterregulation and hypoglycemia without warning symptoms (known as hypoglycemia unawareness) are described, followed by the unifying concept of Hypoglycemia-Associated Autonomie Failure (HAAF). The concept of hypoglycemia-associated autonomie failure in diabetes posits that recurrent antecedent hypoglycemia causes both defective glucose counterregulation and hypoglycemia unawareness and thus leads to a vicious cycle of recurrent hypoglycemia and further impairment of glucose counterregulation. The clinical relevance of this phenomenon is now well established, but the mechanisms and mediators remain largely unknown. The short-term avoidance of hypoglycemia reverses hypoglycemia unawareness in most affected patients. The ultimate goal of lifelong maintenance of euglycemia in patients with diabetes remains elusive because of the pharmacokinetic imperfections of all current glucose-lowering therapies and the resulting barrier of hypoglycemia. Nonetheless, it is now possible both to improve the control of glycemia and to reduce the frequency of hypoglycemia in many people with diabetes. These results can be accomplished by recognizing the problem of hypoglycemia applying the principles of aggressive glycemic therapy and reducing the risk factors of hypoglycemia in people with diabetes.
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Affiliation(s)
- Spyridon O Bakatselos
- Faculty of Medicine, Aristotle University of Thessaloniki, First Department of Internal Medicine, General Hospital of Drama, Drama, Greece.
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van de Ven KCC, de Galan BE, van der Graaf M, Shestov AA, Henry PG, Tack CJJ, Heerschap A. Effect of acute hypoglycemia on human cerebral glucose metabolism measured by ¹³C magnetic resonance spectroscopy. Diabetes 2011; 60:1467-73. [PMID: 21464446 PMCID: PMC3292319 DOI: 10.2337/db10-1592] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To investigate the effect of acute insulin-induced hypoglycemia on cerebral glucose metabolism in healthy humans, measured by (13)C magnetic resonance spectroscopy (MRS). RESEARCH DESIGN AND METHODS Hyperinsulinemic glucose clamps were performed at plasma glucose levels of 5 mmol/L (euglycemia) or 3 mmol/L (hypoglycemia) in random order in eight healthy subjects (four women) on two occasions, separated by at least 3 weeks. Enriched [1-(13)C]glucose 20% w/w was used for the clamps to maintain stable plasma glucose labeling. The levels of the (13)C-labeled glucose metabolites glutamate C4 and C3 were measured over time in the occipital cortex during the clamp by continuous (13)C MRS in a 3T magnetic resonance scanner. Time courses of glutamate C4 and C3 labeling were fitted using a one-compartment model to calculate metabolic rates in the brain. RESULTS Plasma glucose (13)C isotopic enrichment was stable at 35.1 ± 1.8% during euglycemia and at 30.2 ± 5.5% during hypoglycemia. Hypoglycemia stimulated release of counterregulatory hormones (all P < 0.05) and tended to increase plasma lactate levels (P = 0.07). After correction for the ambient (13)C enrichment values, label incorporation into glucose metabolites was virtually identical under both glycemic conditions. Calculated tricarboxylic acid cycle rates (V(TCA)) were 0.48 ± 0.03 μmol/g/min during euglycemia and 0.43 ± 0.08 μmol/g/min during hypoglycemia (P = 0.42). CONCLUSIONS These results indicate that acute moderate hypoglycemia does not affect fluxes through the main pathways of glucose metabolism in the brain of healthy nondiabetic subjects.
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Affiliation(s)
- Kim C C van de Ven
- Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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Graveling A, Frier B. Impaired awareness of hypoglycaemia: a review. DIABETES & METABOLISM 2010; 36 Suppl 3:S64-74. [DOI: 10.1016/s1262-3636(10)70470-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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36
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Heikkilä O, Lundbom N, Timonen M, Groop PH, Heikkinen S, Mäkimattila S. Evidence for abnormal glucose uptake or metabolism in thalamus during acute hyperglycaemia in type 1 diabetes--a 1H MRS study. Metab Brain Dis 2010; 25:227-34. [PMID: 20424902 DOI: 10.1007/s11011-010-9199-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2009] [Accepted: 01/15/2010] [Indexed: 11/24/2022]
Abstract
Acute hyperglycaemia impairs cognitive function. It is however not known, whether different brain regions are equally exposed to glucose during acute hyperglycemia or whether the brain is able to adjust its glucose uptake or metabolism in response to blood glucose fluctuation. We studied the effect of acute hyperglycaemia on the brain glucose concentration in seven men with type 1 diabetes with daily glucose fluctuations of 11 +/- 3 mmol/l, and in eleven age-matched non-diabetic men. Glucose was quantified with proton magnetic resonance spectroscopy in three different brain regions at baseline (fasting glycaemia) and twice during a 2 h hyperglycaemic clamp with plasma glucose increase of 12 mmol/l. The increase in brain glucose during acute hyperglycaemia in the non-diabetic group was: cortex (2.7 +/- 0.9 mmol/l) > thalamus (2.3 +/- 0.7 mmol/l) > white matter (1.7 +/- 0.7 mmol/l, P = 0.021 vs. cortex) and in the diabetic group: cortex (2.0 +/- 0.7 mmol/l) > white matter (1.3 +/- 0.7 mmol/l) > thalamus (1.1 +/- 0.4 mmol/l, P = 0.010 vs. cortex). In the diabetic group, the glucose increase in the thalamus was attenuated compared to the non-diabetic participants (P = 0.011). In conclusion, the increase of glucose during acute hyperglycaemia seems to be dependent on the brain tissue type. The high exposure of cortex to excess glucose and the altered glucose uptake or metabolism in the thalamus may thus contribute to hyperglycaemia related cognitive dysfunction.
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Affiliation(s)
- Outi Heikkilä
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Haarmaninkatu 8, Helsinki, Finland.
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37
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Heikkilä O, Mäkimattila S, Timonen M, Groop PH, Heikkinen S, Lundbom N. Cerebellar Glucose During Fasting and Acute Hyperglycemia in Nondiabetic Men and in Men with Type 1 Diabetes. THE CEREBELLUM 2010; 9:336-44. [DOI: 10.1007/s12311-010-0166-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Affiliation(s)
- Stephanie A. Amiel
- From the Department of Medicine, King's College London School of Medicine, London, England
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39
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Bie-Olsen LG, Kjaer TW, Pedersen-Bjergaard U, Lonsdale MN, Holst JJ, Law I, Thorsteinsson B. Changes of cognition and regional cerebral activity during acute hypoglycemia in normal subjects: A H215O positron emission tomographic study. J Neurosci Res 2009; 87:1922-8. [DOI: 10.1002/jnr.22002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Spring-Robinson C, Chandramouli V, Schumann WC, Faulhaber PF, Wang Y, Wu C, Ismail-Beigi F, Muzic RF. Uptake of 18F-labeled 6-fluoro-6-deoxy-D-glucose by skeletal muscle is responsive to insulin stimulation. J Nucl Med 2009; 50:912-9. [PMID: 19443592 DOI: 10.2967/jnumed.109.062687] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED We are developing a methodology for the noninvasive imaging of glucose transport in vivo with PET and (18)F-labeled 6-fluoro-6-deoxy-d-glucose ((18)F-6FDG), a tracer that is transported but not phosphorylated. To validate the method, we evaluated the biodistribution of (18)F-6FDG to test whether it is consistent with the known properties of glucose transport, particularly with regard to insulin stimulation of glucose transport. METHODS Under glucose clamp conditions, rats were imaged at the baseline and under conditions of hyperinsulinemia. RESULTS The images showed that the radioactivity concentration in skeletal muscle was higher in the presence of insulin than at the baseline. We also found evidence that the metabolism of (18)F-6FDG was negligible in several tissues. CONCLUSION (18)F-6FDG is a valid tracer that can be used in in vivo transport studies. PET studies performed under glucose clamp conditions demonstrated that the uptake of nonphosphorylated glucose transport tracer (18)F-6FDG is sensitive to insulin stimulation.
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Affiliation(s)
- Chandra Spring-Robinson
- Department of Biomedical Engineering, University Hospitals Case Medical Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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Correction for the effect of rising plasma glucose levels on quantification of MR(glc) with FDG-PET. J Cereb Blood Flow Metab 2009; 29:1059-67. [PMID: 19293824 DOI: 10.1038/jcbfm.2009.21] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Positron emission tomography (PET) using the tracer [18F]-fluorodeoxyglucose (FDG) is commonly used for measuring metabolic rate of glucose (MR(glc)) in the human brain. Conventional PET methods (e.g., the Patlak method) for quantifying MR(glc) assume the tissue transport and phosphorylation mechanisms to be in steady state during FDG uptake. As FDG and glucose use the same transporters and phosphorylation enzymes, changing blood glucose levels can change the rates of FDG transport and phosphorylation. Compartmental models were used to simulate the effect of rising arterial glucose, from normal to hyperglycemic levels on FDG uptake for a typical PET protocol. The subsequent errors on the values of MR(glc) calculated using the Patlak method were investigated, and a correction scheme based on measured arterial glucose concentration (G(p)) was evaluated. Typically, with a 40% rise in G(p) over the duration of the PET study, the true MR(glc) varied by only 1%; however, the Patlak method overestimated MR(glc) by 15%. The application of the correction reduced this error to approximately 2%. In general, the application of the correction resulted in values of MR(glc) consistently significantly closer to the true steady state calculation of MR(glc) independently of changes to the parameters defining the model.
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Abstract
Development of therapeutic measures to reduce the risk of potentially fatal episodes of hypoglycaemia and thus to achieve the full benefits of intensive insulin therapy in diabetic patients requires a complete understanding of the multi-factorial mechanisms for repeated hypoglycaemia-induced blunting of the sympatho-adrenal response (BSAR). After critical analysis of the hypotheses, this review paper suggests a heuristic theory. This theory suggests two mechanisms for the BSAR, each involving a critical role for the central brain noradrenergic system. Furthermore, this theory also suggests that the lateral hypothalamus (LH) plays an important role in this phenomenon. Within the framework of this theory, explanations for 1) sexual dimorphism in the adrenomedullary response (AR), 2) dissociation in the blunting of the AR and the sympathetic response (SR) and 3) antecedent exercise-induced blunting of the AR are provided. In addition, habituation of orexin-A neurons is suggested to cause defective awakening. Moreover, potential therapeutics measures have been also suggested that will reduce or prevent severe episodes of hypoglycaemia.
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Affiliation(s)
- B Parekh
- Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK.
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Nery M. [Hypoglycemia as a limiting factor in the management of type 1 diabetes]. ACTA ACUST UNITED AC 2009; 52:288-98. [PMID: 18438539 DOI: 10.1590/s0004-27302008000200016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Accepted: 12/03/2007] [Indexed: 01/31/2023]
Abstract
Type 1 diabetic patients frequently present hypoglycemic episodes during their insulinotherapy, which, besides the discomfort and constrains does not allow the ideal glycemic control. Further, hypoglycemic events lead to the deficiency of the counter-regulation mechanisms in the subsequent episode, with a decrease in the release of epinephrine and the symptoms of warming, with great risk of severe hypoglycemia. The occurrence of hypoglycemia during some risky activities, specially driving, could result in accidents with the patient and /or third parts including property damage, stressing here the need to advise diabetics against having the necessary caution while driving. Generally the connective recovery is total after correcting a hypoglycemic coma. However when these episodes are repetitive, particularly in children, they could result in definitive cognitive disturbances. Hypoglycemic events without a warning signal (hypoglycemic unawareness) are difficult to reverse, thus it is necessary to prevent their occurrence, adjusting the treatment with glycemic targets, using continuous glucose monitoring at home and teaching them how to have an early recognition of hypoglycemia.
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Affiliation(s)
- Márcia Nery
- Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
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Musen G, Simonson DC, Bolo NR, Driscoll A, Weinger K, Raji A, Théberge J, Renshaw PF, Jacobson AM. Regional brain activation during hypoglycemia in type 1 diabetes. J Clin Endocrinol Metab 2008; 93:1450-7. [PMID: 18198228 PMCID: PMC2291497 DOI: 10.1210/jc.2007-2007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Mechanisms underlying the brain response to hypoglycemia are not well understood. OBJECTIVE Our objective was to determine the blood glucose level at which the hypothalamus and other brain regions are activated in response to hypoglycemia in type 1 diabetic patients and control subjects. DESIGN This was a cross-sectional study evaluating brain activity using functional magnetic resonance imaging in conjunction with a hyperinsulinemic hypoglycemic clamp to lower glucose from euglycemia (90 mg/dl) to hypoglycemia (50 mg/dl). SETTING The study was performed at the Brain Imaging Center in the McLean Hospital. STUDY PARTICIPANTS Seven type 1 diabetic patients between 18 and 50 yr old and six matched control subjects were included in the study. INTERVENTION Hyperinsulinemic hypoglycemic clamp was performed. MAIN OUTCOME MEASURES Blood glucose level at peak hypothalamic activation, amount of regional brain activity during hypoglycemia in both groups, and difference in regional brain activation between groups were calculated. RESULTS The hypothalamic region activates at 68 +/- 9 mg/dl in control subjects and 76 +/- 8 mg/dl in diabetic patients during hypoglycemia induction. Brainstem, anterior cingulate cortex, uncus, and putamen were activated in both groups (P < 0.001). Each group also activated unique brain areas not active in the other group. CONCLUSIONS This application of functional magnetic resonance imaging can be used to identify the glucose level at which the hypothalamus is triggered in response to hypoglycemia and whether this threshold differs across patient populations. This study suggests that a core network of brain regions is recruited during hypoglycemia in both diabetic patients and control subjects.
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Affiliation(s)
- Gail Musen
- Research Division, Joslin Diabetes Center, 1 Joslin Place Room 350, Boston, Massachusetts 02215, USA.
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Herzog RI, Chan O, Yu S, Dziura J, McNay EC, Sherwin RS. Effect of acute and recurrent hypoglycemia on changes in brain glycogen concentration. Endocrinology 2008; 149:1499-504. [PMID: 18187548 PMCID: PMC2276713 DOI: 10.1210/en.2007-1252] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Our objective was to evaluate whether excessive brain glycogen deposition might follow episodes of acute hypoglycemia (AH) and thus play a role in the hypoglycemia-associated autonomic failure seen in diabetic patients receiving intensive insulin treatment. We determined brain glucose and glycogen recovery kinetics after AH and recurrent hypoglycemia (RH), an established animal model of counterregulatory failure. A single bout of insulin-induced AH or RH for 3 consecutive days was used to deplete brain glucose and glycogen stores in rats. After microwave fixation and glycogen extraction, regional recovery kinetics in the brain was determined using a biochemical assay. Both AH and RH treatments reduced glycogen levels in the cerebellum, cortex, and hypothalamus from control levels of 7.78 +/- 0.55, 5.4 +/- 0.38, and 4.45 +/- 0.37 micromol/g, respectively, to approximately 50% corresponding to a net glycogen utilization rate between 0.6 and 1.2 micromol/g.h. After hypoglycemia, glycogen levels returned to baseline within 6 h in both the AH and the RH group. However, recovery of brain glycogen tended to be faster in rats exposed to RH. This effect followed more rapid recovery of brain glucose levels in the RH group, despite similar blood glucose levels in both groups. There was no statistically significant increase above baseline glycogen levels in either group. In particular, brain glycogen was not increased 24 h after the last of recurrent episodes of hypoglycemia, when a significant counterregulatory defect could be documented during a hyperinsulinemic hypoglycemic clamp study. We conclude that glycogen supercompensation is not a major contributory factor to the pathogenesis of hypoglycemia-associated autonomic failure.
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Affiliation(s)
- Raimund I Herzog
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06520, USA
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Al-Saeedi FJ. Perfusion scanning using 99mTc-HMPAO detects early cerebrovascular changes in the diabetic rat. BMC MEDICAL PHYSICS 2008; 8:1. [PMID: 18559077 PMCID: PMC2322850 DOI: 10.1186/1756-6649-8-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 03/13/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND 99mTc-HMPAO is a well-established isotope useful in the detection of regional cerebral blood flow. Diabetes gives rise to arterial atherosclerotic changes that can lead to significant end organ dysfunction, prominently affecting perfusion to the heart, kidneys, eyes and brain. In the current study, we investigated the role of 99mTc-HMPAO cerebral perfusion scans in detecting early vascular changes in the diabetic brain. METHODS Cerebral perfusion studies were performed on both control and streptozotocin-(STZ) induced diabetic male Wistar rats. Rat brain imaging using a gamma camera was performed for each group 0.5, 2, 4, and 24 hours post 99mTc-HMPAO injection. Data processing for each cerebral perfusion scan was performed by drawing a region of interest (ROI) circumferentially around the brain (B). Background (BKG) due to signal from the soft tissue of each rat was subtracted. Brain 99mTc-HMPAO uptake minus background counts (net brain counts; NBC) were then compared between the two groups. RESULTS The NBC (mean +/- SD) for the STZ group were statistically significantly higher (p = 0.0004) than those of the control group at each of the time points studied. CONCLUSION 99mTc-HMPAO brain scan may be useful in the detection of early atherosclerotic changes in the diabetic rat brain.
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Affiliation(s)
- Fatma J Al-Saeedi
- Nuclear Medicine Department, Faculty of Medicine, Kuwait University, Kuwait.
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Rossetti P, Porcellati F, Bolli GB, Fanelli CG. Prevention of hypoglycemia while achieving good glycemic control in type 1 diabetes: the role of insulin analogs. Diabetes Care 2008; 31 Suppl 2:S113-20. [PMID: 18227470 DOI: 10.2337/dc08-s227] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Paolo Rossetti
- Department of Internal Medicine, University of Perugia, Perugia, Italy
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Dunn JT, Cranston I, Marsden PK, Amiel SA, Reed LJ. Attenuation of amydgala and frontal cortical responses to low blood glucose concentration in asymptomatic hypoglycemia in type 1 diabetes: a new player in hypoglycemia unawareness? Diabetes 2007; 56:2766-73. [PMID: 17660265 DOI: 10.2337/db07-0666] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Loss of ability to recognize hypoglycemia (hypoglycemia unawareness) increases risk of severe hypoglycemia threefold in insulin-treated diabetes. We set out to investigate the cerebral correlates of unawareness in type 1 patients. RESEARCH DESIGN AND METHODS Regional changes in brain glucose kinetics were measured using [(18)F]-fluorodeoxyglucose (FDG) positron emission tomography (PET), in 13 men with type 1 diabetes--6 with hypoglycemia awareness and 7 with hypoglycemia unawareness--at euglycemia (5 mmol/l) and hypoglycemia (2.6 mmol/l), in random order. RESULTS Epinephrine responses to hypoglycemia were reduced in hypoglycemia unawareness (P < 0.0003), as were symptoms. Statistical parametric mapping (SPM) of FDG uptake using SPM2 at a statistical threshold of P < 0.005 showed increased FDG uptake in left amygdala in hypoglycemia awareness, but not in hypoglycemia unawareness (region of interest analysis -0.40 +/- 1.03 vs. 3.66 +/- 0.42, respectively; P = 0.007), and robust increase in bilateral ventral striatum during hypoglycemia (region of interest analysis hypoglycemia unawareness 3.52 +/- 1.02 vs. awareness 6.1 +/- 0.53; P = 0.054). Further analysis at the statistical threshold of P < 0.01 showed bilateral attenuated activation of brain stem regions and less deactivation in lateral orbitofrontal cortex in hypoglycemia unawareness. CONCLUSIONS Ventral striatal, amygdala, brain stem, and orbitofrontal responses to hypoglycemia indicate engagement of appetitive motivational networks, associated with integrated behavioral responses to hypoglycemia. Reduced responses in these networks in hypoglycemia unawareness, particularly failure of amygdala and orbifrontal cortex responses, suggest habituation of higher behavioral responses to hypoglycemia as a basis for unawareness. New approaches may be needed to restore awareness effectively in practice.
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Affiliation(s)
- Joel T Dunn
- Diabetes Research Group, King's College London School of Medicine, King's College, London, UK
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Landau BR, Spring-Robinson CL, Muzic RF, Rachdaoui N, Rubin D, Berridge MS, Schumann WC, Chandramouli V, Kern TS, Ismail-Beigi F. 6-Fluoro-6-deoxy-D-glucose as a tracer of glucose transport. Am J Physiol Endocrinol Metab 2007; 293:E237-45. [PMID: 17405828 DOI: 10.1152/ajpendo.00022.2007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucose transport rates are estimated noninvasively in physiological and pathological states by kinetic imaging using PET. The glucose analog most often used is (18)F-labeled 2FDG. Compared with glucose, 2FDG is poorly transported by intestine and kidney. We examined the possible use of 6FDG as a tracer of glucose transport. Lacking a hydroxyl at its 6th position, 6FDG cannot be phosphorylated as 2FDG is. Prior studies have shown that 6FDG competes with glucose for transport in yeast and is actively transported by intestine. Its uptake by muscle has been reported to be unresponsive to insulin, but that study is suspect. We found that insulin stimulated 6FDG uptake 1.6-fold in 3T3-L1 adipocytes and azide stimulated the uptake 3.7-fold in Clone 9 cells. Stimulations of the uptake of 3OMG, commonly used in transport assays, were similar, and the uptakes were inhibited by cyclochalasin B. Glucose transport is by GLUT1 and GLUT4 transporters in 3T3-L1 adipocyte and by the GLUT1 transporter in Clone 9 cells. Cytochalasin B inhibits those transporters. Rats were also imaged in vivo by PET using 6(18)FDG. There was no excretion of (18)F into the urinary bladder unless phlorizin, an inhibitor of active renal transport, was also injected. (18)F activity in brain, liver, and heart over the time of scanning reached a constant level, in keeping with the 6FDG being distributed in body water. In contrast, (18)F from 2(18)FDG was excreted in relatively large amounts into the bladder, and (18)F activity rose with time in heart and brain in accord with accumulation of 2(18)FDG-6-P in those organs. We conclude that 6FDG is actively transported by kidney as well as intestine and is insulin responsive. In trace quantity, it appears to be distributed in body water unchanged. These results provide support for its use as a valid tracer of glucose transport.
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Affiliation(s)
- Bernard R Landau
- Department of Radiology, University Hospitals Case Medical Center, 11100 Euclid Avenue, Cleveland, OH 44106-4951, USA
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Cryer PE. Hypoglycemia in diabetes: pathophysiological mechanisms and diurnal variation. PROGRESS IN BRAIN RESEARCH 2006; 153:361-5. [PMID: 16876586 DOI: 10.1016/s0079-6123(06)53021-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Iatrogenic hypoglycemia, the limiting factor in the glycemic management of diabetes, causes recurrent morbidity (and sometimes death), precludes maintenance of euglycemia over a lifetime of diabetes and causes a vicious cycle of recurrent hypoglycemia. In insulin deficient - T1DM and advanced T2DM - diabetes hypoglycemia is the result of the interplay of therapeutic insulin excess and compromised physiological (defective glucose counterregulation) and behavioral (hypoglycemia unawareness) defenses against falling plasma glucose concentrations. The concept of hypoglycemia-associated autonomic failure (HAAF) in diabetes posits that recent antecedent hypoglycemia causes both defective glucose counterregulation (by reducing epinephrine responses in the setting of absent insulin and glucagon responses) and hypoglycemia unawareness (by reducing sympathoadrenal and the resulting neurogenic symptom responses) and thus a vicious cycle of recurrent hypoglycemia. The clinical impact of HAAF-including its reversal by avoidance of hypoglycemia-is well established, but its mechanisms are largely unknown. Loss of the glucagon response, a key feature of defective glucose counterregulation, is plausibly attributed to insulin deficiency, specifically loss of the decrement in intraislet insulin that normally signals glucagon secretion as glucose levels fall. Reduced neurogenic symptoms, a key feature of hypoglycemia unawareness, are largely the result of reduced sympathetic neural responses to falling glucose levels. The mechanism(s) by which hypoglycemia shifts the glycemic thresholds for sympathoadrenal activation to lower plasma glucose concentrations, the key feature of both components of HAAF, is not known. It does not appear to be the result of the release of a systemic mediator such as cortisol or epinephrine during antecedent hypoglycemia or of increased blood-to-brain glucose transport. It is likely the result of an as yet to be identified alteration of brain metabolism. While the research focus has been largely on the hypothalamus, hypoglycemia is known to activate widespread brain regions including the medial prefrontal cortex. The possibility of post-hypoglycemic brain glycogen supercompensation has also been raised. Finally, a unifying mechanism of HAAF would need to incorporate the effects of sleep and antecedent exercise which produce a phenomenon similar to hypoglycemia induced HAAF.
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Affiliation(s)
- Philip E Cryer
- Division of Endocrinology, Metabolism and Lipid Research, and the General Clinical Research Center and the Diabetes Research and Training Center, Washington University School of Medicine, St. Louis, MO, USA.
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