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Ellis RJ, Marquine MJ, Kaul M, Fields JA, Schlachetzki JCM. Mechanisms underlying HIV-associated cognitive impairment and emerging therapies for its management. Nat Rev Neurol 2023; 19:668-687. [PMID: 37816937 PMCID: PMC11052664 DOI: 10.1038/s41582-023-00879-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2023] [Indexed: 10/12/2023]
Abstract
People living with HIV are affected by the chronic consequences of neurocognitive impairment (NCI) despite antiretroviral therapies that suppress viral replication, improve health and extend life. Furthermore, viral suppression does not eliminate the virus, and remaining infected cells may continue to produce viral proteins that trigger neurodegeneration. Comorbidities such as diabetes mellitus are likely to contribute substantially to CNS injury in people living with HIV, and some components of antiretroviral therapy exert undesirable side effects on the nervous system. No treatment for HIV-associated NCI has been approved by the European Medicines Agency or the US Food and Drug Administration. Historically, roadblocks to developing effective treatments have included a limited understanding of the pathophysiology of HIV-associated NCI and heterogeneity in its clinical manifestations. This heterogeneity might reflect multiple underlying causes that differ among individuals, rather than a single unifying neuropathogenesis. Despite these complexities, accelerating discoveries in HIV neuropathogenesis are yielding potentially druggable targets, including excessive immune activation, metabolic alterations culminating in mitochondrial dysfunction, dysregulation of metal ion homeostasis and lysosomal function, and microbiome alterations. In addition to drug treatments, we also highlight the importance of non-pharmacological interventions. By revisiting mechanisms implicated in NCI and potential interventions addressing these mechanisms, we hope to supply reasons for optimism in people living with HIV affected by NCI and their care providers.
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Affiliation(s)
- Ronald J Ellis
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.
| | - María J Marquine
- Department of Medicine, Duke University, Durham, NC, USA
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
| | - Marcus Kaul
- School of Medicine, Division of Biomedical Sciences, University of California Riverside, Riverside, CA, USA
| | - Jerel Adam Fields
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Johannes C M Schlachetzki
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
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2
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Rhea EM, Leclerc M, Yassine HN, Capuano AW, Tong H, Petyuk VA, Macauley SL, Fioramonti X, Carmichael O, Calon F, Arvanitakis Z. State of the Science on Brain Insulin Resistance and Cognitive Decline Due to Alzheimer's Disease. Aging Dis 2023:AD.2023.0814. [PMID: 37611907 DOI: 10.14336/ad.2023.0814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) is common and increasing in prevalence worldwide, with devastating public health consequences. While peripheral insulin resistance is a key feature of most forms of T2DM and has been investigated for over a century, research on brain insulin resistance (BIR) has more recently been developed, including in the context of T2DM and non-diabetes states. Recent data support the presence of BIR in the aging brain, even in non-diabetes states, and found that BIR may be a feature in Alzheimer's disease (AD) and contributes to cognitive impairment. Further, therapies used to treat T2DM are now being investigated in the context of AD treatment and prevention, including insulin. In this review, we offer a definition of BIR, and present evidence for BIR in AD; we discuss the expression, function, and activation of the insulin receptor (INSR) in the brain; how BIR could develop; tools to study BIR; how BIR correlates with current AD hallmarks; and regional/cellular involvement of BIR. We close with a discussion on resilience to both BIR and AD, how current tools can be improved to better understand BIR, and future avenues for research. Overall, this review and position paper highlights BIR as a plausible therapeutic target for the prevention of cognitive decline and dementia due to AD.
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Affiliation(s)
- Elizabeth M Rhea
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA
| | - Manon Leclerc
- Faculty of Pharmacy, Laval University, Quebec, Quebec, Canada
- Neuroscience Axis, CHU de Québec Research Center - Laval University, Quebec, Quebec, Canada
| | - Hussein N Yassine
- Departments of Neurology and Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Ana W Capuano
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Han Tong
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Vladislav A Petyuk
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Shannon L Macauley
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA
| | - Xavier Fioramonti
- Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33000 Bordeaux, France
- International Associated Laboratory OptiNutriBrain, Bordeaux, France and Quebec, Canada
| | - Owen Carmichael
- Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Frederic Calon
- Faculty of Pharmacy, Laval University, Quebec, Quebec, Canada
- Neuroscience Axis, CHU de Québec Research Center - Laval University, Quebec, Quebec, Canada
- International Associated Laboratory OptiNutriBrain, Bordeaux, France and Quebec, Canada
| | - Zoe Arvanitakis
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
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3
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Daniel JM, Lindsey SH, Mostany R, Schrader LA, Zsombok A. Cardiometabolic health, menopausal estrogen therapy and the brain: How effects of estrogens diverge in healthy and unhealthy preclinical models of aging. Front Neuroendocrinol 2023; 70:101068. [PMID: 37061205 PMCID: PMC10725785 DOI: 10.1016/j.yfrne.2023.101068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/23/2023] [Accepted: 04/10/2023] [Indexed: 04/17/2023]
Abstract
Research in preclinical models indicates that estrogens are neuroprotective and positively impact cognitive aging. However, clinical data are equivocal as to the benefits of menopausal estrogen therapy to the brain and cognition. Pre-existing cardiometabolic disease may modulate mechanisms by which estrogens act, potentially reducing or reversing protections they provide against cognitive decline. In the current review we propose mechanisms by which cardiometabolic disease may alter estrogen effects, including both alterations in actions directly on brain memory systems and actions on cardiometabolic systems, which in turn impact brain memory systems. Consideration of mechanisms by which estrogen administration can exert differential effects dependent upon health phenotype is consistent with the move towards precision or personalized medicine, which aims to determine which treatment interventions will work for which individuals. Understanding effects of estrogens in both healthy and unhealthy models of aging is critical to optimizing the translational link between preclinical and clinical research.
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Affiliation(s)
- Jill M Daniel
- Department of Psychology and Brain Institute, Tulane University, New Orleans, LA, United States.
| | - Sarah H Lindsey
- Department of Pharmacology and Brain Institute, Tulane University, New Orleans, LA, United States
| | - Ricardo Mostany
- Department of Pharmacology and Brain Institute, Tulane University, New Orleans, LA, United States
| | - Laura A Schrader
- Department of Cell & Molecular Biology and Brain Institute, Tulane University, New Orleans, LA, United States
| | - Andrea Zsombok
- Department of Physiology and Brain Institute, Tulane University, New Orleans, LA, United States
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4
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Fitzgerald GS, Chuchta TG, McNay EC. Insulin‐like growth factor‐2 is a promising candidate for the treatment and prevention of Alzheimer's disease. CNS Neurosci Ther 2023; 29:1449-1469. [PMID: 36971212 PMCID: PMC10173726 DOI: 10.1111/cns.14160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 02/06/2023] [Accepted: 02/22/2023] [Indexed: 03/29/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia. Current AD treatments slow the rate of cognitive decline, but do not restore lost function. One reason for the low efficacy of current treatments is that they fail to target neurotrophic processes, which are thought to be essential for functional recovery. Bolstering neurotrophic processes may also be a viable strategy for preventative treatment, since structural losses are thought to underlie cognitive decline in AD. The challenge of identifying presymptomatic patients who might benefit from preventative treatment means that any such treatment must meet a high standard of safety and tolerability. The neurotrophic peptide insulin-like growth factor-2 (IGF2) is a promising candidate for both treating and preventing AD-induced cognitive decline. Brain IGF2 expression declines in AD patients. In rodent models of AD, exogenous IGF2 modulates multiple aspects of AD pathology, resulting in (1) improved cognitive function; (2) stimulation of neurogenesis and synaptogenesis; and, (3) neuroprotection against cholinergic dysfunction and beta amyloid-induced neurotoxicity. Preclinical evidence suggests that IGF2 is likely to be safe and tolerable at therapeutic doses. In the preventative treatment context, the intranasal route of administration is likely to be the preferred method for achieving the therapeutic effect without risking adverse side effects. For patients already experiencing AD dementia, routes of administration that deliver IGF2 directly access the CNS may be necessary. Finally, we discuss several strategies for improving the translational validity of animal models used to study the therapeutic potential of IGF2.
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Affiliation(s)
| | | | - E C McNay
- University at Albany, Albany, New York, USA
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5
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Actions and Consequences of Insulin in the Striatum. Biomolecules 2023; 13:biom13030518. [PMID: 36979453 PMCID: PMC10046598 DOI: 10.3390/biom13030518] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 03/14/2023] Open
Abstract
Insulin crosses the blood–brain barrier to enter the brain from the periphery. In the brain, insulin has well-established actions in the hypothalamus, as well as at the level of mesolimbic dopamine neurons in the midbrain. Notably, insulin also acts in the striatum, which shows abundant expression of insulin receptors (InsRs) throughout. These receptors are found on interneurons and striatal projections neurons, as well as on glial cells and dopamine axons. A striking functional consequence of insulin elevation in the striatum is promoting an increase in stimulated dopamine release. This boosting of dopamine release involves InsRs on cholinergic interneurons, and requires activation of nicotinic acetylcholine receptors on dopamine axons. Opposing this dopamine-enhancing effect, insulin also increases dopamine uptake through the action of insulin at InsRs on dopamine axons. Insulin acts on other striatal cells as well, including striatal projection neurons and astrocytes that also influence dopaminergic transmission and striatal function. Linking these cellular findings to behavior, striatal insulin signaling is required for the development of flavor–nutrient learning, implicating insulin as a reward signal in the brain. In this review, we discuss these and other actions of insulin in the striatum, including how they are influenced by diet and other physio-logical states.
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6
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Guan J, Li F, Kang D, Anderson T, Pitcher T, Dalrymple-Alford J, Shorten P, Singh-Mallah G. Cyclic Glycine-Proline (cGP) Normalises Insulin-Like Growth Factor-1 (IGF-1) Function: Clinical Significance in the Ageing Brain and in Age-Related Neurological Conditions. Molecules 2023; 28:molecules28031021. [PMID: 36770687 PMCID: PMC9919809 DOI: 10.3390/molecules28031021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/20/2023] Open
Abstract
Insulin-like growth factor-1 (IGF-1) function declines with age and is associated with brain ageing and the progression of age-related neurological conditions. The reversible binding of IGF-1 to IGF binding protein (IGFBP)-3 regulates the amount of bioavailable, functional IGF-1 in circulation. Cyclic glycine-proline (cGP), a metabolite from the binding site of IGF-1, retains its affinity for IGFBP-3 and competes against IGF-1 for IGFBP-3 binding. Thus, cGP and IGFBP-3 collectively regulate the bioavailability of IGF-1. The molar ratio of cGP/IGF-1 represents the amount of bioavailable and functional IGF-1 in circulation. The cGP/IGF-1 molar ratio is low in patients with age-related conditions, including hypertension, stroke, and neurological disorders with cognitive impairment. Stroke patients with a higher cGP/IGF-1 molar ratio have more favourable clinical outcomes. The elderly with more cGP have better memory retention. An increase in the cGP/IGF-1 molar ratio with age is associated with normal cognition, whereas a decrease in this ratio with age is associated with dementia in Parkinson disease. In addition, cGP administration reduces systolic blood pressure, improves memory, and aids in stroke recovery. These clinical and experimental observations demonstrate the role of cGP in regulating IGF-1 function and its potential clinical applications in age-related brain diseases as a plasma biomarker for-and an intervention to improve-IGF-1 function.
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Affiliation(s)
- Jian Guan
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medicine and Health Sciences, School of Biomedical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Centre for Brain Research, Faculty of Medicine and Health Sciences, School of Biomedical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Brain Research New Zealand, The Centre for Research Excellent, Dunedin 9016, New Zealand
- The cGP Lab Limited New Zealand, Auckland 1021, New Zealand
- Correspondence: ; Tel.: +64-9-923-6134
| | - Fengxia Li
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medicine and Health Sciences, School of Biomedical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Centre for Brain Research, Faculty of Medicine and Health Sciences, School of Biomedical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou 510075, China
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen 518107, China
| | - Dali Kang
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medicine and Health Sciences, School of Biomedical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Centre for Brain Research, Faculty of Medicine and Health Sciences, School of Biomedical Sciences, The University of Auckland, Auckland 1142, New Zealand
- Brain Research New Zealand, The Centre for Research Excellent, Dunedin 9016, New Zealand
- Shenyang Medical College, Shenyang 110034, China
| | - Tim Anderson
- New Zealand Brain Research Institute, Christchurch 4710, New Zealand
- Department of Medicine, University of Otago, Dunedin 9016, New Zealand
- Department of Neurology, Canterbury District Health Board, Christchurch 4710, New Zealand
| | - Toni Pitcher
- New Zealand Brain Research Institute, Christchurch 4710, New Zealand
- Department of Medicine, University of Otago, Dunedin 9016, New Zealand
- Department of Neurology, Canterbury District Health Board, Christchurch 4710, New Zealand
| | - John Dalrymple-Alford
- Department of Neurology, Canterbury District Health Board, Christchurch 4710, New Zealand
- Department of Psychology, University of Canterbury, Christchurch 4710, New Zealand
| | - Paul Shorten
- AgResearch Ltd., Ruakura Research Centre, Hamilton 3214, New Zealand
- Riddet Institute, Massey University, Palmerston North 4474, New Zealand
| | - Gagandeep Singh-Mallah
- Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden
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7
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Leclerc M, Bourassa P, Tremblay C, Caron V, Sugère C, Emond V, Bennett DA, Calon F. Cerebrovascular insulin receptors are defective in Alzheimer's disease. Brain 2023; 146:75-90. [PMID: 36280236 PMCID: PMC9897197 DOI: 10.1093/brain/awac309] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/24/2022] [Accepted: 08/12/2022] [Indexed: 01/11/2023] Open
Abstract
Central response to insulin is suspected to be defective in Alzheimer's disease. As most insulin is secreted in the bloodstream by the pancreas, its capacity to regulate brain functions must, at least partly, be mediated through the cerebral vasculature. However, how insulin interacts with the blood-brain barrier and whether alterations of this interaction could contribute to Alzheimer's disease pathophysiology both remain poorly defined. Here, we show that human and murine cerebral insulin receptors (INSRs), particularly the long isoform INSRα-B, are concentrated in microvessels rather than in the parenchyma. Vascular concentrations of INSRα-B were lower in the parietal cortex of subjects diagnosed with Alzheimer's disease, positively correlating with cognitive scores, leading to a shift towards a higher INSRα-A/B ratio, consistent with cerebrovascular insulin resistance in the Alzheimer's disease brain. Vascular INSRα was inversely correlated with amyloid-β plaques and β-site APP cleaving enzyme 1, but positively correlated with insulin-degrading enzyme, neprilysin and P-glycoprotein. Using brain cerebral intracarotid perfusion, we found that the transport rate of insulin across the blood-brain barrier remained very low (<0.03 µl/g·s) and was not inhibited by an insulin receptor antagonist. However, intracarotid perfusion of insulin induced the phosphorylation of INSRβ that was restricted to microvessels. Such an activation of vascular insulin receptor was blunted in 3xTg-AD mice, suggesting that Alzheimer's disease neuropathology induces insulin resistance at the level of the blood-brain barrier. Overall, the present data in post-mortem Alzheimer's disease brains and an animal model of Alzheimer's disease indicate that defects in the insulin receptor localized at the blood-brain barrier strongly contribute to brain insulin resistance in Alzheimer's disease, in association with β-amyloid pathology.
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Affiliation(s)
- Manon Leclerc
- Faculté de Pharmacie, Université Laval, Québec, QC G1V 0A6, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC G1V 4G2, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, QC G1V 0A6, Canada
| | - Philippe Bourassa
- Faculté de Pharmacie, Université Laval, Québec, QC G1V 0A6, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC G1V 4G2, Canada
| | - Cyntia Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC G1V 4G2, Canada
| | - Vicky Caron
- Faculté de Pharmacie, Université Laval, Québec, QC G1V 0A6, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC G1V 4G2, Canada
| | - Camille Sugère
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC G1V 4G2, Canada
| | - Vincent Emond
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC G1V 4G2, Canada
| | - David A Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Frédéric Calon
- Faculté de Pharmacie, Université Laval, Québec, QC G1V 0A6, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC G1V 4G2, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, QC G1V 0A6, Canada
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8
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Falling Short: The Contribution of Central Insulin Receptors to Gait Dysregulation in Brain Aging. Biomedicines 2022; 10:biomedicines10081923. [PMID: 36009470 PMCID: PMC9405648 DOI: 10.3390/biomedicines10081923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/27/2022] [Accepted: 07/29/2022] [Indexed: 11/23/2022] Open
Abstract
Insulin resistance, which manifests as a reduction of insulin receptor signaling, is known to correlate with pathological changes in peripheral tissues as well as in the brain. Central insulin resistance has been associated with impaired cognitive performance, decreased neuronal health, and reduced brain metabolism; however, the mechanisms underlying central insulin resistance and its impact on brain regions outside of those associated with cognition remain unclear. Falls are a leading cause of both fatal and non-fatal injuries in the older population. Despite this, there is a paucity of work focused on age-dependent alterations in brain regions associated with ambulatory control or potential therapeutic approaches to target these processes. Here, we discuss age-dependent alterations in central modalities that may contribute to gait dysregulation, summarize current data supporting the role of insulin signaling in the brain, and highlight key findings that suggest insulin receptor sensitivity may be preserved in the aged brain. Finally, we present novel results showing that administration of insulin to the somatosensory cortex of aged animals can alter neuronal communication, cerebral blood flow, and the motivation to ambulate, emphasizing the need for further investigations of intranasal insulin as a clinical management strategy in the older population.
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9
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García-Aviles JE, Méndez-Hernández R, Guzmán-Ruiz MA, Cruz M, Guerrero-Vargas NN, Velázquez-Moctezuma J, Hurtado-Alvarado G. Metabolic Disturbances Induced by Sleep Restriction as Potential Triggers for Alzheimer's Disease. Front Integr Neurosci 2021; 15:722523. [PMID: 34539357 PMCID: PMC8447653 DOI: 10.3389/fnint.2021.722523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 07/26/2021] [Indexed: 01/15/2023] Open
Abstract
Sleep has a major role in learning, memory consolidation, and metabolic function. Although it is known that sleep restriction increases the accumulation of amyloid β peptide (Aβ) and the risk to develop Alzheimer's disease (AD), the mechanism behind these effects remains unknown. In this review, we discuss how chronic sleep restriction induces metabolic and cognitive impairments that could result in the development of AD in late life. Here, we integrate evidence regarding mechanisms whereby metabolic signaling becomes disturbed after short or chronic sleep restriction in the context of cognitive impairment, particularly in the accumulation of Aβ in the brain. We also discuss the role of the blood-brain barrier in sleep restriction with an emphasis on the transport of metabolic signals into the brain and Aβ clearance. This review presents the unexplored possibility that the alteration of peripheral metabolic signals induced by sleep restriction, especially insulin resistance, is responsible for cognitive deficit and, subsequently, implicated in AD development.
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Affiliation(s)
- Jesús Enrique García-Aviles
- Area of Neurosciences, Biology of Reproduction Department, Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City, Mexico.,Posgrado en Biología Experimental, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City, Mexico
| | - Rebeca Méndez-Hernández
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Mara A Guzmán-Ruiz
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Miguel Cruz
- Instituto Mexicano del Seguro Social, Centro Médico Nacional Siglo XXI, Hospital de Especialidades, Unidad de Investigación Médica en Bioquímica, Mexico City, Mexico
| | - Natalí N Guerrero-Vargas
- Departamento de Anatomía, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - Javier Velázquez-Moctezuma
- Area of Neurosciences, Biology of Reproduction Department, Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Mexico City, Mexico
| | - Gabriela Hurtado-Alvarado
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
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10
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Frazier HN, Ghoweri AO, Sudkamp E, Johnson ES, Anderson KL, Fox G, Vatthanaphone K, Xia M, Lin RL, Hargis-Staggs KE, Porter NM, Pauly JR, Blalock EM, Thibault O. Long-Term Intranasal Insulin Aspart: A Profile of Gene Expression, Memory, and Insulin Receptors in Aged F344 Rats. J Gerontol A Biol Sci Med Sci 2021; 75:1021-1030. [PMID: 31180116 DOI: 10.1093/gerona/glz105] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Indexed: 02/06/2023] Open
Abstract
Intranasal insulin is a safe and effective method for ameliorating memory deficits associated with pathological brain aging. However, the impact of different formulations and the duration of treatment on insulin's efficacy and the cellular processes targeted by the treatment remain unclear. Here, we tested whether intranasal insulin aspart, a short-acting insulin formulation, could alleviate memory decline associated with aging and whether long-term treatment affected regulation of insulin receptors and other potential targets. Outcome variables included measures of spatial learning and memory, autoradiography and immunohistochemistry of the insulin receptor, and hippocampal microarray analyses. Aged Fischer 344 rats receiving long-term (3 months) intranasal insulin did not show significant memory enhancement on the Morris water maze task. Autoradiography results showed that long-term treatment reduced insulin binding in the thalamus but not the hippocampus. Results from hippocampal immunofluorescence revealed age-related decreases in insulin immunoreactivity that were partially offset by intranasal administration. Microarray analyses highlighted numerous insulin-sensitive genes, suggesting insulin aspart was able to enter the brain and alter hippocampal RNA expression patterns including those associated with tumor suppression. Our work provides insights into potential mechanisms of intranasal insulin and insulin resistance, and highlights the importance of treatment duration and the brain regions targeted.
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Affiliation(s)
| | | | - Emily Sudkamp
- The College of Pharmacy, University of Kentucky, Lexington, Kentucky
| | | | | | - Grant Fox
- Department of Pharmacology and Nutritional Sciences
| | | | - Mengfan Xia
- Department of Pharmacology and Nutritional Sciences
| | | | | | | | - James R Pauly
- The College of Pharmacy, University of Kentucky, Lexington, Kentucky
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11
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Lin C, Lin Y, Luo J, Yu J, Cheng Y, Wu X, Lin L, Lin Y. Maternal High-Fat Diet Multigenerationally Impairs Hippocampal Synaptic Plasticity and Memory in Male Rat Offspring. Endocrinology 2021; 162:bqaa214. [PMID: 33211807 DOI: 10.1210/endocr/bqaa214] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Indexed: 12/14/2022]
Abstract
As advances are made in the field of developmental origins of health and disease, there is an emphasis on long-term influence of maternal environmental factors on offspring health. Maternal high-fat diet (HFD) consumption has been suggested to exert detrimental effects on cognitive function in offspring, but whether HFD-dependent brain remodeling can be transmitted to the next generations is still unclear. This study tested the hypothesis that HFD consumption during rat pregnancy and lactation multigenerationally influences male offspring hippocampal synaptic plasticity and cognitive function. We observed that hippocampus-dependent learning and memory was impaired in 3 generations from HFD-fed maternal ancestors (referred as F1-F3), as assessed by novel object recognition and Morris water maze tests. Moreover, maternal HFD exposure also affected electrophysiological and ultrastructure measures of hippocampal synaptic plasticity across generations. We observed that intranasal insulin replacement partially rescued hippocampal synaptic plasticity and cognitive deficits in F3 rats, suggesting central insulin resistance may play an important role in maternal diet-induced neuroplasticity impairment. Furthermore, maternal HFD exposure enhanced the palmitoylation of GluA1 critically involved in long-term potentiation induction, while palmitoylation inhibitor 2-bromopalmitate counteracts GluA1 hyperpalmitoylation and partially abolishes the detrimental effects of maternal diet on learning and memory in F3 offspring. Importantly, maternal HFD-dependent GluA1 hyperpalmitoylation was reversed by insulin replacement. Taken together, our data suggest that maternal HFD exposure multigenerationally influences adult male offspring hippocampal synaptic plasticity and cognitive performance, and central insulin resistance may serve as the cross-talk between maternal diet and cognitive impairment across generations.
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Affiliation(s)
- Cheng Lin
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - YanYan Lin
- Department of Neurology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Ji Luo
- Department of Neurology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - JunRu Yu
- Department of Neurology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
- Department of Neurology, Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - YaNi Cheng
- Department of Neurology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - XiaoYun Wu
- Department of Neurology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Lin Lin
- Department of Gynecology and Obstetrics, Wenzhou Hospital of Traditional Chinese Medicine, Wenzhou, China
| | - YuanShao Lin
- Department of Neurology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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12
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Frazier HN, Anderson KL, Ghoweri AO, Lin RL, Hawkinson TR, Popa GJ, Sompol P, Mendenhall MD, Norris CM, Thibault O. Molecular elevation of insulin receptor signaling improves memory recall in aged Fischer 344 rats. Aging Cell 2020; 19:e13220. [PMID: 32852134 PMCID: PMC7576226 DOI: 10.1111/acel.13220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 12/24/2022] Open
Abstract
As demonstrated by increased hippocampal insulin receptor density following learning in animal models and decreased insulin signaling, receptor density, and memory decline in aging and Alzheimer's diseases, numerous studies have emphasized the importance of insulin in learning and memory processes. This has been further supported by work showing that intranasal delivery of insulin can enhance insulin receptor signaling, alter cerebral blood flow, and improve memory recall. Additionally, inhibition of insulin receptor function or expression using molecular techniques has been associated with reduced learning. Here, we sought a different approach to increase insulin receptor activity without the need for administering the ligand. A constitutively active, modified human insulin receptor (IRβ) was delivered to the hippocampus of young (2 months) and aged (18 months) male Fischer 344 rats in vivo. The impact of increasing hippocampal insulin receptor expression was investigated using several outcome measures, including Morris water maze and ambulatory gait performance, immunofluorescence, immunohistochemistry, and Western immunoblotting. In aged animals, the IRβ construct was associated with enhanced performance on the Morris water maze task, suggesting that this receptor was able to improve memory recall. Additionally, in both age-groups, a reduced stride length was noted in IRβ-treated animals along with elevated hippocampal insulin receptor levels. These results provide new insights into the potential impact of increasing neuronal insulin signaling in the hippocampus of aged animals and support the efficacy of molecularly elevating insulin receptor activity in vivo in the absence of the ligand to directly study this process.
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Affiliation(s)
| | - Katie L. Anderson
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
| | - Adam O. Ghoweri
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
| | - Ruei-Lung Lin
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
| | - Tara R. Hawkinson
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
| | - Gabriel J. Popa
- Department of Molecular and Cellular BiochemistryLexingtonKentuckyUSA
| | - Pradoldej Sompol
- Sanders-Brown Center on AgingUniversity of KentuckyLexingtonKentuckyUSA
| | | | | | - Olivier Thibault
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
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13
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Frazier HN, Ghoweri AO, Anderson KL, Lin RL, Popa GJ, Mendenhall MD, Reagan LP, Craven RJ, Thibault O. Elevating Insulin Signaling Using a Constitutively Active Insulin Receptor Increases Glucose Metabolism and Expression of GLUT3 in Hippocampal Neurons. Front Neurosci 2020; 14:668. [PMID: 32733189 PMCID: PMC7358706 DOI: 10.3389/fnins.2020.00668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/02/2020] [Indexed: 12/31/2022] Open
Abstract
Insulin signaling is an integral component of healthy brain function, with evidence of positive insulin-mediated alterations in synaptic integrity, cerebral blood flow, inflammation, and memory. However, the specific pathways targeted by this peptide remain unclear. Previously, our lab used a molecular approach to characterize the impact of insulin signaling on voltage-gated calcium channels and has also shown that acute insulin administration reduces calcium-induced calcium release in hippocampal neurons. Here, we explore the relationship between insulin receptor signaling and glucose metabolism using similar methods. Mixed, primary hippocampal cultures were infected with either a control lentivirus or one containing a constitutively active human insulin receptor (IRβ). 2-NBDG imaging was used to obtain indirect measures of glucose uptake and utilization. Other outcome measures include Western immunoblots of GLUT3 and GLUT4 on total membrane and cytosolic subcellular fractions. Glucose imaging data indicate that neurons expressing IRβ show significant elevations in uptake and rates of utilization compared to controls. As expected, astrocytes did not respond to the IRβ treatment. Quantification of Western immunoblots show that IRβ is associated with significant elevations in GLUT3 expression, particularly in the total membrane subcellular fraction, but did not alter GLUT4 expression in either fraction. Our work suggests that insulin plays a significant role in mediating neuronal glucose metabolism, potentially through an upregulation in the expression of GLUT3. This provides further evidence for a potential therapeutic mechanism underlying the beneficial impact of intranasal insulin in the clinic.
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Affiliation(s)
- Hilaree N Frazier
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Adam O Ghoweri
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Katie L Anderson
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Ruei-Lung Lin
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Gabriel J Popa
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Michael D Mendenhall
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Lawrence P Reagan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Rolf J Craven
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Olivier Thibault
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, United States
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14
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Deme P, Rojas C, Slusher BS, Rais R, Afghah Z, Geiger JD, Haughey NJ. Bioenergetic adaptations to HIV infection. Could modulation of energy substrate utilization improve brain health in people living with HIV-1? Exp Neurol 2020; 327:113181. [PMID: 31930991 PMCID: PMC7233457 DOI: 10.1016/j.expneurol.2020.113181] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/18/2022]
Abstract
The human brain consumes more energy than any other organ in the body and it relies on an uninterrupted supply of energy in the form of adenosine triphosphate (ATP) to maintain normal cognitive function. This constant supply of energy is made available through an interdependent system of metabolic pathways in neurons, glia and endothelial cells that each have specialized roles in the delivery and metabolism of multiple energetic substrates. Perturbations in brain energy metabolism is associated with a number of different neurodegenerative conditions including impairments in cognition associated with infection by the Human Immunodeficiency Type 1 Virus (HIV-1). Adaptive changes in brain energy metabolism are apparent early following infection, do not fully normalize with the initiation of antiretroviral therapy (ART), and often worsen with length of infection and duration of anti-retroviral therapeutic use. There is now a considerable amount of cumulative evidence that suggests mild forms of cognitive impairments in people living with HIV-1 (PLWH) may be reversible and are associated with specific modifications in brain energy metabolism. In this review we discuss brain energy metabolism with an emphasis on adaptations that occur in response to HIV-1 infection. The potential for interventions that target brain energy metabolism to preserve or restore cognition in PLWH are also discussed.
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Affiliation(s)
- Pragney Deme
- The Johns Hopkins University School of Medicine, Department of Neurology, United States
| | - Camilo Rojas
- The Johns Hopkins University School of Medicine, Department of Comparative Medicine and Pathobiology, United States
| | - Barbara S Slusher
- The Johns Hopkins University School of Medicine, Department of Neurology, United States; The Johns Hopkins University School of Medicine, Department of The Solomon H. Snyder Department of Neuroscience, United States; The Johns Hopkins University School of Medicine, Department of Comparative Medicine and Pathobiology, United States; The Johns Hopkins University School of Medicine, Department of Psychiatry, United States
| | - Raina Rais
- The Johns Hopkins University School of Medicine, Department of Neurology, United States; The Johns Hopkins University School of Medicine, Department of The Solomon H. Snyder Department of Neuroscience, United States; The Johns Hopkins University School of Medicine, Department of Comparative Medicine and Pathobiology, United States; The Johns Hopkins University School of Medicine, Department of Psychiatry, United States
| | - Zahra Afghah
- The University of North Dakota School of Medicine and Health Sciences, Department of Biomedical Sciences, United States
| | - Jonathan D Geiger
- The University of North Dakota School of Medicine and Health Sciences, Department of Biomedical Sciences, United States
| | - Norman J Haughey
- The Johns Hopkins University School of Medicine, Department of Neurology, United States; The Johns Hopkins University School of Medicine, Department of Psychiatry, United States.
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15
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Fan D, Pitcher T, Dalrymple‐Alford J, MacAskill M, Anderson T, Guan J. Changes of plasma cGP/IGF-1 molar ratio with age is associated with cognitive status of Parkinson disease. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2020; 12:e12025. [PMID: 32671179 PMCID: PMC7346731 DOI: 10.1002/dad2.12025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 01/09/2020] [Accepted: 01/23/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Cognitive impairment is a common feature of Parkinson disease (PD), for which age is a major contributing factor. Insulin-like growth factor-1 (IGF-1) declines with age and contributes to age-related cognitive impairment in PD. Cyclic glycine-proline (cGP) is a metabolite of IGF-1 and normalizes bioavailable IGF-1. Plasma cGP/IGF-1 molar ratio that represents bioactive IGF-1 in circulation, may associate with the cognitive status in PD. METHODS We examined the association of plasma cGP/IGF-1 molar ratio with the cognitive scores or age in PD patients with normal cognition (PD-N, n = 74), mild cognitive impairment (PD-MCI, n = 71), or dementia (PD-D, n = 33), and with the cognitive scores in 23 age-matched healthy controls. Plasma concentrations of IGF-1, IGF binding protein-3, and cGP were evaluated using enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography-mass spectrometry (HPLC-MS), respectively. RESULTS The cGP/IGF-1 molar ratio was positively correlated with the age of PD-N group, negatively correlated with the age of PD-D group, and not associated with the age of PD-MCI group. Independent of age, the cGP/IGF-1 molar ratio was positively correlated with the cognitive scores of healthy controls, but not in PD groups. CONCLUSION Old healthy people with a higher cGP/IGF-1 molar ratio showed better preserved cognition, possibly due to improved IGF-1 function. Increased cGP/IGF-1 molar ratio with age may contribute to cognitive retention in the PD-N group. The absence or reversal of such association with age in the PD-MCI and PD-D groups may indicate the conversion of cognitive status in PD, if confirmed through longitudinal investigations within the individuals with advancing cognitive impairment.
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Affiliation(s)
- Dawei Fan
- Department of Pharmacology and Clinical PharmacologySchool of Medical SciencesFaculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
- Centre for Brain ResearchSchool of Medical SciencesFaculty of Medical and Health ScienceUniversity of AucklandAucklandNew Zealand
- Brain Research New Zealand, A Centre of Research ExcellenceAucklandNew Zealand
| | - Toni Pitcher
- Brain Research New Zealand, A Centre of Research ExcellenceAucklandNew Zealand
- New Zealand Brain Research InstituteChristchurchNew Zealand
- Department of MedicineUniversity of OtagoDunedinNew Zealand
| | - John Dalrymple‐Alford
- Brain Research New Zealand, A Centre of Research ExcellenceAucklandNew Zealand
- New Zealand Brain Research InstituteChristchurchNew Zealand
- Department of PsychologyUniversity of CanterburyChristchurchNew Zealand
| | - Michael MacAskill
- New Zealand Brain Research InstituteChristchurchNew Zealand
- Department of MedicineUniversity of OtagoDunedinNew Zealand
| | - Tim Anderson
- Brain Research New Zealand, A Centre of Research ExcellenceAucklandNew Zealand
- New Zealand Brain Research InstituteChristchurchNew Zealand
- Department of MedicineUniversity of OtagoDunedinNew Zealand
- Department of NeurologyCanterbury District Health BoardChristchurchNew Zealand
| | - Jian Guan
- Department of Pharmacology and Clinical PharmacologySchool of Medical SciencesFaculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
- Centre for Brain ResearchSchool of Medical SciencesFaculty of Medical and Health ScienceUniversity of AucklandAucklandNew Zealand
- Brain Research New Zealand, A Centre of Research ExcellenceAucklandNew Zealand
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16
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Peters R, White D, Cleeland C, Scholey A. Fuel for Thought? A Systematic Review of Neuroimaging Studies into Glucose Enhancement of Cognitive Performance. Neuropsychol Rev 2020; 30:234-250. [PMID: 32162177 PMCID: PMC7305087 DOI: 10.1007/s11065-020-09431-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 02/17/2020] [Indexed: 01/08/2023]
Abstract
A transient improvement in cognitive performance can be observed following the ingestion of a glucose drink, a phenomenon known as the ‘glucose facilitation effect’. The effect has been studied thoroughly in the last three decades, but its neural underpinnings remain a matter of speculation. A systematic review was conducted to evaluate the current evidence from studies applying neuroimaging or neurophysiological methods to investigate the glucose enhancement effect. Eleven studies met the inclusion criteria of using neuroimaging in conjunction with cognitive outcomes. Six studies employed electroencephalography (EEG), four used functional magnetic resonance imaging (fMRI) and one employed functional near-infrared spectroscopy (fNIRS). All but one study reported modulation of neurophysiology or neuroimaging markers following glucose, while only five studies reported significant changes in cognitive outcomes. The evidence suggests that glucose administration enhances neurocognitive markers of episodic memory and attentional processes underpinned by medial temporal and frontal activation, sometimes in the absence of measurable behavioural effects. Further exploration of glucose facilitation using neuroimaging measures with increased sample sizes is warranted to replicate these findings.
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Affiliation(s)
- Riccarda Peters
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, 3122, Australia
| | - David White
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, 3122, Australia
| | - Carlee Cleeland
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, 3122, Australia
| | - Andrew Scholey
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, 3122, Australia.
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17
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Lv H, Tang L, Guo C, Jiang Y, Gao C, Wang Y, Jian C. Intranasal insulin administration may be highly effective in improving cognitive function in mice with cognitive dysfunction by reversing brain insulin resistance. Cogn Neurodyn 2020; 14:323-338. [PMID: 32399074 DOI: 10.1007/s11571-020-09571-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 10/17/2019] [Accepted: 01/31/2020] [Indexed: 02/06/2023] Open
Abstract
It is well known in clinical practice that Alzheimer's disease (AD) is closely associated with brain insulin resistance, and the cerebral insulin pathway has been proven to play a critical role in the pathogenesis of AD. However, finding the most efficient way to improve brain insulin resistance remains challenging. Peripheral administration of insulin does not have the desired therapeutic effect and may induce adverse reactions, such as hyperinsulinemia, but intranasal administration may be an efficient way. In the present study, we established a brain insulin resistance model through an intraventricular injection of streptozotocin, accompanied by cognitive impairment. Following intranasal insulin treatment, the learning and memory functions of mice were significantly restored, the neurogenesis in the hippocampus was improved, the level of insulin in the brain increased, and the activation of the IRS-1-PI3K-Akt-GSK3β insulin signal pathway, but not the Ras-Raf-MEK-MAPK pathway, was markedly increased. The olfactory bulb-subventricular zone-subgranular zone (OB-SVZ-SGZ) axis might be the mechanism through which intranasal insulin regulates cognition in brain-insulin-resistant mice. Thus, intranasal insulin administration may be a highly efficient way to improve cognitive function by increasing cerebral insulin levels and reversing insulin resistance.
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Affiliation(s)
- Hui Lv
- 1Youjiang Medical University for Nationalities, Chengxiang Avenue, Youjiang District, Baise, 533000 Guangxi People's Republic of China
| | - Lingjiao Tang
- 1Youjiang Medical University for Nationalities, Chengxiang Avenue, Youjiang District, Baise, 533000 Guangxi People's Republic of China
| | - Canshou Guo
- The 6th Hospital of Wu Han, Wuhan, 430015 Hubei People's Republic of China
| | - Yongming Jiang
- 2Graduate College of Youjiang Medical University for Nationalities, Chengxiang Avenue, Youjiang District, Baise, 533000 Guangxi People's Republic of China
| | - Ce Gao
- 2Graduate College of Youjiang Medical University for Nationalities, Chengxiang Avenue, Youjiang District, Baise, 533000 Guangxi People's Republic of China
| | - Yifan Wang
- 2Graduate College of Youjiang Medical University for Nationalities, Chengxiang Avenue, Youjiang District, Baise, 533000 Guangxi People's Republic of China
| | - Chongdong Jian
- 1Youjiang Medical University for Nationalities, Chengxiang Avenue, Youjiang District, Baise, 533000 Guangxi People's Republic of China
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18
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Farruggia MC, Small DM. Effects of adiposity and metabolic dysfunction on cognition: A review. Physiol Behav 2019; 208:112578. [PMID: 31194997 PMCID: PMC6625347 DOI: 10.1016/j.physbeh.2019.112578] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/29/2019] [Accepted: 06/09/2019] [Indexed: 12/31/2022]
Abstract
Obesity and metabolic dysfunction are both correlated with increased rates of cognitive decline. However, because these two conditions often co-occur, it remains unclear whether their cognitive consequences are independent. In this review, we carefully consider literature examining the effects of metabolic dysfunction and increased adiposity on cognition across the lifespan, including only well-controlled studies that attempt to dissociate their effects. We found a total of 36 studies, 17 examining metabolic dysfunction and 19 examining the effects of adiposity. We found evidence from the literature suggesting that increased adiposity and metabolic dysfunction may contribute to deficits in executive function, memory, and medial temporal lobe structures largely independent of one another. These deficits are thought to arise principally from physiological changes associated with inflammation, vascularization, and oxidative stress, among others. Such processes may result from excess adipose tissue and insulin resistance that occur independently and can further exacerbate when the two conditions co-occur. However, we also find it likely that impaired cognition plays a role in behavioral and lifestyle choices that lead to increased adiposity and metabolic dysfunction, which can then perpetuate and augment cognitive decline. We recommend additional prospective and longitudinal studies to examine whether impaired cognition is a cause and/or consequence of these factors.
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Affiliation(s)
- Michael C Farruggia
- Interdepartmental Neuroscience Program, Yale University, 333 Cedar Street, New Haven, CT, USA; Department of Psychiatry, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, USA.
| | - Dana M Small
- Interdepartmental Neuroscience Program, Yale University, 333 Cedar Street, New Haven, CT, USA; Department of Psychiatry, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, USA; Department of Psychology, Yale University, New Haven, CT, USA; fMEG Center, University of Tubingen, Tubingen, Germany.
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19
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Frangou S, Shirali M, Adams MJ, Howard DM, Gibson J, Hall LS, Smith BH, Padmanabhan S, Murray AD, Porteous DJ, Haley CS, Deary IJ, Clarke TK, McIntosh AM. Insulin resistance: Genetic associations with depression and cognition in population based cohorts. Exp Neurol 2019; 316:20-26. [PMID: 30965038 PMCID: PMC6503941 DOI: 10.1016/j.expneurol.2019.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 03/26/2019] [Accepted: 04/03/2019] [Indexed: 01/07/2023]
Abstract
Insulin resistance, broadly defined as the reduced ability of insulin to exert its biological action, has been associated with depression and cognitive dysfunction in observational studies. However, it is unclear whether these associations are causal and whether they might be underpinned by other shared factors. To address this knowledge gap, we capitalized on the stability of genetic biomarkers through the lifetime, and on their unidirectional relationship with depression and cognition. Specifically, we determined the association between quantitative measures of cognitive function and depression and genetic instruments of insulin resistance traits in two large-scale population samples, the Generation Scotland: Scottish Family Health Study (GS: SFHS; N = 19,994) and in the UK Biobank (N = 331,374). In the GS:SFHS, the polygenic risk score (PRS) for fasting insulin was associated with verbal intelligence and depression while the PRS for the homeostasis model assessment of insulin resistance was associated with verbal intelligence. Despite this overlap in genetic architecture, Mendelian randomization analyses in the GS:SFHS and in the UK Biobank samples did not yield evidence for causal associations from insulin resistance traits to either depression or cognition. These findings may be due to weak genetic instruments, limited cognitive measures and insufficient power but they may also indicate the need to identify other biological mechanisms that may mediate the relationship from insulin resistance to depression and cognition. Insulin resistance (INS-R) is broadly defined as the reduced ability of insulin to exert its biological action. Measures of INS- R are associated with depression and cognitive dysfunction. We used two large population samples to estimate genetic associations. The polygenic risk of INS-R was associated with depression and cognition this association did not appear to be causal.
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Affiliation(s)
- Sophia Frangou
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Masoud Shirali
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, UK
| | - Mark J Adams
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, UK
| | - David M Howard
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, UK
| | - Jude Gibson
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, UK
| | - Lynsey S Hall
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, UK
| | - Blair H Smith
- Division of Population Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Sandosh Padmanabhan
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Alison D Murray
- Aberdeen Biomedical Imaging Centre, University of Aberdeen, Aberdeen, UK
| | - David J Porteous
- Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK; Generation Scotland, Medical Genetics Section, Centre for Genomic and Experimental Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Chris S Haley
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Ian J Deary
- Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK; Department of Psychology, University of Edinburgh, Edinburgh, UK
| | - Toni-Kim Clarke
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, UK
| | - Andrew M McIntosh
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, UK; Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK; Department of Psychology, University of Edinburgh, Edinburgh, UK
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20
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Alterations in effective connectivity within the Papez circuit are correlated with insulin resistance in T2DM patients without mild cognitive impairment. Brain Imaging Behav 2019; 14:1238-1246. [DOI: 10.1007/s11682-019-00049-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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21
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Jeong JH, Koo JH, Cho JY, Kang EB. Neuroprotective effect of treadmill exercise against blunted brain insulin signaling, NADPH oxidase, and Tau hyperphosphorylation in rats fed a high-fat diet. Brain Res Bull 2018; 142:374-383. [DOI: 10.1016/j.brainresbull.2018.08.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/08/2018] [Accepted: 08/01/2018] [Indexed: 11/24/2022]
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22
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Lee TK, Chen BH, Lee JC, Shin MC, Cho JH, Lee HA, Choi JH, Hwang IK, Kang IJ, Ahn JH, Park JH, Choi SY, Won MH. Age‑dependent decreases in insulin‑like growth factor‑I and its receptor expressions in the gerbil olfactory bulb. Mol Med Rep 2018; 17:8161-8166. [PMID: 29658594 PMCID: PMC5983990 DOI: 10.3892/mmr.2018.8886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 04/06/2018] [Indexed: 12/23/2022] Open
Abstract
Insulin-like growth factor-I (IGF-I) is a multifunctional protein present in the central nervous system. A number of previous studies have revealed alterations in IGF-I and its receptor (IGF-IR) expression in various regions of the brain. However, there are few reports on age-dependent alterations in IGF-I and IGF-IR expressions in the olfactory bulb, which contains the secondary neurons of the olfactory system. The present study examined the cellular morphology in the olfactory bulb by using cresyl violet (CV) staining at postnatal month (PM) 3 in the young group, PM 6 in the adult group and PM 24 in the aged group in gerbils. In addition, detailed examinations were performed of the protein levels and immunoreactivities of IGF-I and IGF-IR in the olfactory bulb in each group. There were no significant changes in the cellular morphology between the three groups. The protein levels and immunoreactivities of the IGF-I and IGF-IR were the highest in the young group and they decreased with age. He protein levels and immunoreactivities of the IGF-I and IGF-IR were the lowest in the aged group. In brief, our results indicate that IGF-I and IGF-IR expressions are strong in young olfactory bulbs and significantly reduced in aged olfactory bulbs. In conclusion, subsequent decreases in IGF-I and IGF-IR expression with age may be associated with olfactory decline. Further studies are required to investigate the roles of IFG-I and IGF-IR in disorders of the olfactory system.
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Affiliation(s)
- Tae-Kyeong Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Bai Hui Chen
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Jae-Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Myoung Cheol Shin
- Department of Emergency Medicine, School of Medicine, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jun Hwi Cho
- Department of Emergency Medicine, School of Medicine, Chuncheon, Gangwon 24341, Republic of Korea
| | - Hyang-Ah Lee
- Department of Obstetrics and Gynecology, School of Medicine, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jung Hoon Choi
- Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Il Jun Kang
- Department of Food Science and Nutrition, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea
| | - Ji Hyeon Ahn
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea
| | - Joon Ha Park
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea
| | - Soo Young Choi
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
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23
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McEwen BS. Redefining neuroendocrinology: Epigenetics of brain-body communication over the life course. Front Neuroendocrinol 2018; 49:8-30. [PMID: 29132949 DOI: 10.1016/j.yfrne.2017.11.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 11/01/2017] [Accepted: 11/04/2017] [Indexed: 12/15/2022]
Abstract
The brain is the central organ of stress and adaptation to stress that perceives and determines what is threatening, as well as the behavioral and physiological responses to the stressor, and it does so somewhat differently in males and females. The expression of steroid hormone receptors throughout the brain has broadened the definition of 'neuroendocrinology' to include the reciprocal communication between the entire brain and body via hormonal and neural pathways. Mediated in part via systemic hormonal influences, the adult and developing brain possess remarkable structural and functional plasticity in response to stress, including neuronal replacement, dendritic remodeling, and synapse turnover. This article is both an account of an emerging field elucidating brain-body interactions at multiple levels, from molecules to social organization, as well as a personal account of my laboratory's role and, most importantly, the roles of trainees and colleagues, along with my involvement in interdisciplinary groups working on this topic.
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Affiliation(s)
- Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA. http://www.rockefeller.edu/labheads/mcewen/mcewen-lab.php
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The impact of diet-based glycaemic response and glucose regulation on cognition: evidence across the lifespan. Proc Nutr Soc 2017; 76:466-477. [DOI: 10.1017/s0029665117000829] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The brain has a high metabolic rate and its metabolism is almost entirely restricted to oxidative utilisation of glucose. These factors emphasise the extreme dependence of neural tissue on a stable and adequate supply of glucose. Whereas initially it was thought that only glucose deprivation (i.e. under hypoglycaemic conditions) can affect brain function, it has become apparent that low-level fluctuations in central availability can affect neural and consequently, cognitive performance. In the present paper the impact of diet-based glycaemic response and glucose regulation on cognitive processes across the lifespan will be reviewed. The data suggest that although an acute rise in blood glucose levels has some short-term improvements of cognitive function, a more stable blood glucose profile, which avoids greater peaks and troughs in circulating glucose is associated with better cognitive function and a lower risk of cognitive impairments in the longer term. Therefore, a habitual diet that secures optimal glucose delivery to the brain in the fed and fasting states should be most advantageous for the maintenance of cognitive function. Although the evidence to date is promising, it is insufficient to allow firm and evidence-based nutritional recommendations. The rise in obesity, diabetes and metabolic syndrome in recent years highlights the need for targeted dietary and lifestyle strategies to promote healthy lifestyle and brain function across the lifespan and for future generations. Consequently, there is an urgent need for hypothesis-driven, randomised controlled trials that evaluate the role of different glycaemic manipulations on cognition.
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Abstract
Brain inflammaging is increasingly considered as contributing to age-related cognitive loss and neurodegeneration. Despite intensive research in multiple models, no clinically effective pharmacological treatment has been found yet. Here, in the mouse model of brain senescence SAMP8, we tested the effects of proinsulin, a promising neuroprotective agent that was previously proven to be effective in mouse models of retinal neurodegeneration. Proinsulin is the precursor of the hormone insulin but also upholds developmental physiological effects, particularly as a survival factor for neural cells. Adeno-associated viral vectors of serotype 1 bearing the human proinsulin gene were administered intramuscularly to obtain a sustained release of proinsulin into the blood stream, which was able to reach the target area of the hippocampus. SAMP8 mice and the control strain SAMR1 were treated at 1 month of age. At 6 months, behavioral testing exhibited cognitive loss in SAMP8 mice treated with the null vector. Remarkably, the cognitive performance achieved in spatial and recognition tasks by SAMP8 mice treated with proinsulin was similar to that of SAMR1 mice. In the hippocampus, proinsulin induced the activation of neuroprotective pathways and the downstream signaling cascade, leading to the decrease of neuroinflammatory markers. Furthermore, the decrease of astrocyte reactivity was a central effect, as demonstrated in the connectome network of changes induced by proinsulin. Therefore, the neuroprotective effects of human proinsulin unveil a new pharmacological potential therapy in the fight against cognitive loss in the elderly.
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de Matos AM, de Macedo MP, Rauter AP. Bridging Type 2 Diabetes and Alzheimer's Disease: Assembling the Puzzle Pieces in the Quest for the Molecules With Therapeutic and Preventive Potential. Med Res Rev 2017; 38:261-324. [PMID: 28422298 DOI: 10.1002/med.21440] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/18/2017] [Accepted: 02/14/2017] [Indexed: 12/19/2022]
Abstract
Type 2 diabetes (T2D) and Alzheimer's disease (AD) are two age-related amyloid diseases that affect millions of people worldwide. Broadly supported by epidemiological data, the higher incidence of AD among type 2 diabetic patients led to the recognition of T2D as a tangible risk factor for the development of AD. Indeed, there is now growing evidence on brain structural and functional abnormalities arising from brain insulin resistance and deficiency, ultimately highlighting the need for new approaches capable of preventing the development of AD in type 2 diabetic patients. This review provides an update on overlapping pathophysiological mechanisms and pathways in T2D and AD, such as amyloidogenic events, oxidative stress, endothelial dysfunction, aberrant enzymatic activity, and even shared genetic background. These events will be presented as puzzle pieces put together, thus establishing potential therapeutic targets for drug discovery and development against T2D and diabetes-induced cognitive decline-a heavyweight contributor to the increasing incidence of dementia in developed countries. Hoping to pave the way in this direction, we will present some of the most promising and well-studied drug leads with potential against both pathologies, including their respective bioactivity reports, mechanisms of action, and structure-activity relationships.
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Affiliation(s)
- Ana Marta de Matos
- Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016, Lisbon, Portugal.,CEDOC Chronic Diseases, Nova Medical School, Rua Câmara Pestana n 6, 6-A, Ed. CEDOC II, 1150-082, Lisbon, Portugal
| | - Maria Paula de Macedo
- CEDOC Chronic Diseases, Nova Medical School, Rua Câmara Pestana n 6, 6-A, Ed. CEDOC II, 1150-082, Lisbon, Portugal
| | - Amélia Pilar Rauter
- Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016, Lisbon, Portugal
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Gwon M, Tak YJ, Kim YJ, Lee SY, Lee JG, Jeong DW, Yi YH, Lee SH, Hwang HR, Lee Y. Is Hypovitaminosis D Associated with Stress Perception in the Elderly? A Nationwide Representative Study in Korea. Nutrients 2016; 8:nu8100647. [PMID: 27775565 PMCID: PMC5084034 DOI: 10.3390/nu8100647] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/29/2016] [Accepted: 10/12/2016] [Indexed: 01/24/2023] Open
Abstract
Hypovitaminosis D and stress are common problems among the elderly. The aim of this cross-sectional nationally representative study was to evaluate the association between hypovitaminosis D and stress perception using large-scale nationally representative data from the Korea National Health and Nutrition Examination Survey (2012-2013). In our study, a total of 1393 elders (≥65 years old) were included to evaluate the association between hypovitaminosis D and stress perception. Serum 25-hydroxyvitamin D levels were determined using radioimmunoassay, and perceived stress status was assessed by a self-reporting questionnaire. The association between hypovitaminosis D and stress perception according to sex was examined using logistic regression analysis. After multivariate adjustment for sociodemographic and lifestyle factors and comorbidities, hypovitaminosis D was significantly associated with perceived stress (odds ratio, 2.73; 95% confidence interval, 1.10-6.77; p = 0.029) among women; however, this association was not significant among men. Hypovitaminosis D was a risk factor for higher stress perception in older Korean women. Even though the role of vitamin D in stress perception is still unclear, we suggest screening for hypovitaminosis D among the elderly.
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Affiliation(s)
- Mieun Gwon
- Department of Family Medicine, Pusan National University School of Medicine, Busan 602-739, Korea.
- Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, Korea.
| | - Young Jin Tak
- Department of Family Medicine, Pusan National University School of Medicine, Busan 602-739, Korea.
- Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, Korea.
| | - Yun Jin Kim
- Department of Family Medicine, Pusan National University School of Medicine, Busan 602-739, Korea.
- Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, Korea.
| | - Sang Yeoup Lee
- Medical Education Unit and Medical Research Institute, Pusan National University School of Medicine, Yangsan 626-870, Korea.
- Family Medicine Clinic and Research Institute of Convergence of Biomedical Science and Technology, Pusan National Yangsan Hospital, Yangsan 626-789, Korea.
| | - Jeong Gyu Lee
- Department of Family Medicine, Pusan National University School of Medicine, Busan 602-739, Korea.
- Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, Korea.
| | - Dong Wook Jeong
- Family Medicine Clinic and Research Institute of Convergence of Biomedical Science and Technology, Pusan National Yangsan Hospital, Yangsan 626-789, Korea.
| | - Yu Hyeon Yi
- Department of Family Medicine, Pusan National University School of Medicine, Busan 602-739, Korea.
- Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, Korea.
| | - Seung Hoon Lee
- Department of Family Medicine, Pusan National University School of Medicine, Busan 602-739, Korea.
- Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, Korea.
| | - Hye Rim Hwang
- Department of Family Medicine, Pusan National University School of Medicine, Busan 602-739, Korea.
- Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, Korea.
| | - Youngin Lee
- Department of Family Medicine, Pusan National University School of Medicine, Busan 602-739, Korea.
- Biomedical Research Institute, Pusan National University Hospital, Busan 602-739, Korea.
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Anderson KL, Frazier HN, Maimaiti S, Bakshi VV, Majeed ZR, Brewer LD, Porter NM, Lin AL, Thibault O. Impact of Single or Repeated Dose Intranasal Zinc-free Insulin in Young and Aged F344 Rats on Cognition, Signaling, and Brain Metabolism. J Gerontol A Biol Sci Med Sci 2016; 72:189-197. [PMID: 27069097 DOI: 10.1093/gerona/glw065] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/19/2016] [Indexed: 01/13/2023] Open
Abstract
Novel therapies have turned to delivering compounds to the brain using nasal sprays, bypassing the blood brain barrier, and enriching treatment options for brain aging and/or Alzheimer's disease. We conducted a series of in vivo experiments to test the impact of intranasal Apidra, a zinc-free insulin formulation, on the brain of young and aged F344 rats. Both single acute and repeated daily doses were compared to test the hypothesis that insulin could improve memory recall in aged memory-deficient animals. We quantified insulin signaling in different brain regions and at different times following delivery. We measured cerebral blood flow (CBF) using MRI and also characterized several brain metabolite levels using MR spectroscopy. We show that neither acute nor chronic Apidra improved memory or recall in young or aged animals. Within 2 hours of a single dose, increased insulin signaling was seen in ventral areas of the aged brains only. Although chronic Apidra was able to offset reduced CBF with aging, it also caused significant reductions in markers of neuronal integrity. Our data suggest that this zinc-free insulin formulation may actually hasten cognitive decline with age when used chronically.
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Affiliation(s)
| | | | | | | | - Zana R Majeed
- The School of Biology, University of Kentucky, Lexington
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29
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Fadel JR, Reagan LP. Stop signs in hippocampal insulin signaling: the role of insulin resistance in structural, functional and behavioral deficits. Curr Opin Behav Sci 2015; 9:47-54. [PMID: 26955646 DOI: 10.1016/j.cobeha.2015.12.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In peripheral tissues insulin activates signaling cascades to facilitate glucose uptake from the blood into tissues like liver, muscle and fat. While insulin appears to play a minor role in the regulation of glucose uptake in the central nervous system (CNS), insulin is known to play a major role in regulating synaptic plasticity in brain regions like the hippocampus. The concept that insulin regulates hippocampal neuroplasticity is further supported from animal models of type 2 diabetes (T2DM) and Alzheimer's disease (AD). The goal of this review is to provide an overview of these studies, as well as the studies that have examined whether deficits in hippocampal insulin signaling are amenable to intervention strategies.
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Affiliation(s)
- Jim R Fadel
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Lawrence P Reagan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA; WJB Dorn Veterans Affairs Medical Center, Columbia, SC, USA
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30
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Inflammation and Oxidative Stress: The Molecular Connectivity between Insulin Resistance, Obesity, and Alzheimer's Disease. Mediators Inflamm 2015; 2015:105828. [PMID: 26693205 PMCID: PMC4674598 DOI: 10.1155/2015/105828] [Citation(s) in RCA: 293] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/29/2015] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes (T2DM), Alzheimer's disease (AD), and insulin resistance are age-related conditions and increased prevalence is of public concern. Recent research has provided evidence that insulin resistance and impaired insulin signalling may be a contributory factor to the progression of diabetes, dementia, and other neurological disorders. Alzheimer's disease (AD) is the most common subtype of dementia. Reduced release (for T2DM) and decreased action of insulin are central to the development and progression of both T2DM and AD. A literature search was conducted to identify molecular commonalities between obesity, diabetes, and AD. Insulin resistance affects many tissues and organs, either through impaired insulin signalling or through aberrant changes in both glucose and lipid (cholesterol and triacylglycerol) metabolism and concentrations in the blood. Although epidemiological and biological evidence has highlighted an increased incidence of cognitive decline and AD in patients with T2DM, the common molecular basis of cell and tissue dysfunction is rapidly gaining recognition. As a cause or consequence, the chronic inflammatory response and oxidative stress associated with T2DM, amyloid-β (Aβ) protein accumulation, and mitochondrial dysfunction link T2DM and AD.
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31
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Grillo CA, Piroli GG, Lawrence RC, Wrighten SA, Green AJ, Wilson SP, Sakai RR, Kelly SJ, Wilson MA, Mott DD, Reagan LP. Hippocampal Insulin Resistance Impairs Spatial Learning and Synaptic Plasticity. Diabetes 2015; 64. [PMID: 26216852 PMCID: PMC4613975 DOI: 10.2337/db15-0596] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Insulin receptors (IRs) are expressed in discrete neuronal populations in the central nervous system, including the hippocampus. To elucidate the functional role of hippocampal IRs independent of metabolic function, we generated a model of hippocampal-specific insulin resistance using a lentiviral vector expressing an IR antisense sequence (LV-IRAS). LV-IRAS effectively downregulates IR expression in the rat hippocampus without affecting body weight, adiposity, or peripheral glucose homeostasis. Nevertheless, hippocampal neuroplasticity was impaired in LV-IRAS-treated rats. High-frequency stimulation, which evoked robust long-term potentiation (LTP) in brain slices from LV control rats, failed to evoke LTP in LV-IRAS-treated rats. GluN2B subunit levels, as well as the basal level of phosphorylation of GluA1, were reduced in the hippocampus of LV-IRAS rats. Moreover, these deficits in synaptic transmission were associated with impairments in spatial learning. We suggest that alterations in the expression and phosphorylation of glutamate receptor subunits underlie the alterations in LTP and that these changes are responsible for the impairment in hippocampal-dependent learning. Importantly, these learning deficits are strikingly similar to the impairments in complex task performance observed in patients with diabetes, which strengthens the hypothesis that hippocampal insulin resistance is a key mediator of cognitive deficits independent of glycemic control.
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Affiliation(s)
- Claudia A Grillo
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Gerardo G Piroli
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Robert C Lawrence
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC Department of Psychology, University of South Carolina, Columbia, SC
| | - Shayna A Wrighten
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Adrienne J Green
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Steven P Wilson
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Randall R Sakai
- Department of Psychiatry, University of Cincinnati Medical Center, Cincinnati, OH
| | - Sandra J Kelly
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC Department of Psychology, University of South Carolina, Columbia, SC
| | - Marlene A Wilson
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC William Jennings Bryan Dorn Veterans Affairs Medical Center, Columbia, SC
| | - David D Mott
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Lawrence P Reagan
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC William Jennings Bryan Dorn Veterans Affairs Medical Center, Columbia, SC
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Abstract
Clinical studies suggest a link between type 2 diabetes mellitus (T2DM) and insulin resistance (IR) and cognitive dysfunction, but there are significant gaps in our knowledge of the mechanisms underlying this relationship. Animal models of IR help to bridge these gaps and point to hippocampal IR as a potential mediator of cognitive dysfunction in T2DM, as well as in Alzheimer disease (AD). This Review highlights these observations and discusses intervention studies which suggest that the restoration of insulin activity in the hippocampus may be an effective strategy to alleviate the cognitive decline associated with T2DM and AD.
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Bedse G, Di Domenico F, Serviddio G, Cassano T. Aberrant insulin signaling in Alzheimer's disease: current knowledge. Front Neurosci 2015; 9:204. [PMID: 26136647 PMCID: PMC4468388 DOI: 10.3389/fnins.2015.00204] [Citation(s) in RCA: 196] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/22/2015] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia affecting elderly people. AD is a multifaceted pathology characterized by accumulation of extracellular neuritic plaques, intracellular neurofibrillary tangles (NFTs) and neuronal loss mainly in the cortex and hippocampus. AD etiology appears to be linked to a multitude of mechanisms that have not been yet completely elucidated. For long time, it was considered that insulin signaling has only peripheral actions but now it is widely accepted that insulin has neuromodulatory actions in the brain. Insulin signaling is involved in numerous brain functions including cognition and memory that are impaired in AD. Recent studies suggest that AD may be linked to brain insulin resistance and patients with diabetes have an increased risk of developing AD compared to healthy individuals. Indeed insulin resistance, increased inflammation and impaired metabolism are key pathological features of both AD and diabetes. However, the precise mechanisms involved in the development of AD in patients with diabetes are not yet fully understood. In this review we will discuss the role played by aberrant brain insulin signaling in AD. In detail, we will focus on the role of insulin signaling in the deposition of neuritic plaques and intracellular NFTs. Considering that insulin mitigates beta-amyloid deposition and phosphorylation of tau, pharmacological strategies restoring brain insulin signaling, such as intranasal delivery of insulin, could have significant therapeutic potential in AD treatment.
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Affiliation(s)
- Gaurav Bedse
- Department of Physiology and Pharmacology "V. Erspamer," Sapienza University of Rome Rome, Italy ; Department of Biochemical Sciences, Sapienza University of Rome Rome, Italy
| | - Fabio Di Domenico
- Department of Biochemical Sciences, Sapienza University of Rome Rome, Italy
| | - Gaetano Serviddio
- Department of Medical and Surgical Sciences, University of Foggia Foggia, Italy
| | - Tommaso Cassano
- Department of Clinical and Experimental Medicine, University of Foggia Foggia, Italy
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34
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The role of type 2 diabetes in neurodegeneration. Neurobiol Dis 2015; 84:22-38. [PMID: 25926349 DOI: 10.1016/j.nbd.2015.04.008] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/18/2015] [Accepted: 04/21/2015] [Indexed: 02/07/2023] Open
Abstract
A growing body of evidence links type-2 diabetes (T2D) with dementia and neurodegenerative diseases such as Alzheimer's disease (AD). AD is the most common form of dementia and is characterised neuropathologically by the accumulation of extracellular beta amyloid (Aβ) peptide aggregates and intracellular hyper-phosphorylated tau protein, which are thought to drive and/or accelerate inflammatory and oxidative stress processes leading to neurodegeneration. Although the precise mechanism remains unclear, T2D can exacerbate these neurodegenerative processes. Brain atrophy, reduced cerebral glucose metabolism and CNS insulin resistance are features of both AD and T2D. Cell culture and animal studies have indicated that the early accumulation of Aβ may play a role in CNS insulin resistance and impaired insulin signalling. From the viewpoint of insulin resistance and impaired insulin signalling in the brain, these are also believed to initiate other aspects of brain injury, including inflammatory and oxidative stress processes. Here we review the clinical and experimental pieces of evidence that link these two chronic diseases of ageing, and discuss underlying mechanisms. The evaluation of treatments for the management of diabetes in preclinical, and clinical studies and trials for AD will also be discussed.
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Kealy J, Bennett R, Lowry JP. Real-time effects of insulin-induced hypoglycaemia on hippocampal glucose and oxygen. Brain Res 2014; 1598:76-87. [PMID: 25511995 DOI: 10.1016/j.brainres.2014.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 12/01/2014] [Accepted: 12/05/2014] [Indexed: 01/07/2023]
Abstract
The hippocampus plays a vital role in learning and memory and is susceptible to damage following hypoglycaemic shock. The effect of an acute administration of insulin on hippocampal function has been described in terms of behavioural deficits but its effect on hippocampal oxygen and glucose is unclear. Glucose oxidase biosensors (detecting glucose) and carbon paste electrodes (detecting oxygen) were implanted into the hippocampus of Sprague Dawley rats. Animals were allowed to recover and real-time recordings were made in order to determine the effects of fasting, insulin administration (15 U/kg; i.p.) and reintroduction of food on hippocampal oxygen and glucose. Fasting caused a significant decrease in hippocampal glucose over the course of 24h. Insulin administration produced a significant decrease in hippocampal glucose along with a significant increase in hippocampal oxygen. Finally, the reintroduction of food resulted in glucose levels significantly increasing along with a transient but significant increase in oxygen levels. The findings presented here suggest that even a single acute period of hypoglycaemia may substantially disrupt hippocampal oxygen and glucose and therefore affect hippocampal function.
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Affiliation(s)
- John Kealy
- Maynooth University Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland.
| | - Rachel Bennett
- Maynooth University Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - John P Lowry
- Maynooth University Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland
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36
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Morales González E, Contreras I, Estrada J. Efecto de la deficiencia de hierro sobre la expresión de factor de crecimiento de insulina tipo II y su receptor en células neuronales y gliales. Neurologia 2014; 29:408-15. [DOI: 10.1016/j.nrl.2013.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 10/13/2013] [Indexed: 01/10/2023] Open
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Morales González E, Contreras I, Estrada J. Effect of iron deficiency on the expression of insulin-like growth factor-II and its receptor in neuronal and glial cells. NEUROLOGÍA (ENGLISH EDITION) 2014. [DOI: 10.1016/j.nrleng.2013.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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38
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Johansson J, Grönbladh A, Hallberg M. Gamma-hydroxybutyrate (GHB) induces cognitive deficits and affects GABAB receptors and IGF-1 receptors in male rats. Behav Brain Res 2014; 269:164-74. [DOI: 10.1016/j.bbr.2014.04.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 04/16/2014] [Accepted: 04/19/2014] [Indexed: 12/30/2022]
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39
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Decreased Insulin-Like Growth Factor-I and Its Receptor Expression in the Hippocampus and Somatosensory Cortex of the Aged Mouse. Neurochem Res 2014; 39:770-6. [DOI: 10.1007/s11064-014-1269-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 02/22/2014] [Accepted: 02/25/2014] [Indexed: 10/25/2022]
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40
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Shimomura T, Anan F, Masaki T, Umeno Y, Eshima N, Saikawa T, Yoshimatsu H, Fujiki M, Kobayashi H. Homocysteine levels are associated with hippocampus volume in type 2 diabetic patients. Eur J Clin Invest 2011; 41:751-8. [PMID: 21250986 DOI: 10.1111/j.1365-2362.2010.02464.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Elevated total plasma homocysteine (tHcy) levels are associated with cognitive dysfunction, in which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that elevated tHcy levels are correlated with hippocampus volume and insulin resistance in nondementia patients with type 2 diabetes. MATERIALS AND METHODS The study included 43 nondementia patients with type 2 diabetes, who were divided into two groups: a high tHcy group (age: 65 ± 8 years, mean ± standard deviation, n = 16) and a normal tHcy group (64 ± 9 years, n = 27). Hippocampus volume was quantified with a computer-assisted analysis using a magnetic resonance imaging (MRI) voxel-based specific regional analysis system developed for the study of Alzheimer's disease (VSRAD), which yields a Z-score as the end point for the assessment of hippocampal volume. Results The Z-score was higher in the high tHcy group compared to the normal tHcy group (P < 0·0001). The fasting plasma glucose (P < 0·01) and insulin (P < 0·0001) concentrations and the homoeostasis model assessment (HOMA) index (P < 0·0001) were higher in the high tHcy group than in the normal tHcy group. Multiple regression analysis showed that the main factors that influenced tHcy levels may be the Z-score and the HOMA index. CONCLUSIONS Our results indicate that the elevated levels of tHcy in Japanese nondementia patients with type 2 diabetes are characterised by hippocampal atrophy and insulin resistance and that the Z-score and HOMA index may be the primary factors that influence tHcy levels.
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Affiliation(s)
- Tsuyoshi Shimomura
- Department of Neurosurgery, Faculty of Medicine, Oita University, Oita, Japan.
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41
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Anan F, Masaki T, Shimomura T, Fujiki M, Umeno Y, Eshima N, Saikawa T, Yoshimatsu H. High-sensitivity C-reactive protein is associated with hippocampus volume in nondementia patients with type 2 diabetes mellitus. Metabolism 2011; 60:460-6. [PMID: 20537668 DOI: 10.1016/j.metabol.2010.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 03/30/2010] [Accepted: 04/06/2010] [Indexed: 11/19/2022]
Abstract
The elevated level of high-sensitivity C-reactive protein (HSCRP) is associated with cognitive dysfunction, for which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that an elevated level of HSCRP correlates with hippocampus volume and insulin resistance in nondementia patients with type 2 diabetes mellitus. Subjects included 45 nondementia patients with type 2 diabetes mellitus, who were divided into 2 groups: high-HSCRP group (age, 65 ± 6 years [mean ± SD]; n = 17) and normal-HSCRP group (65 ± 7 years, n = 28). Hippocampus volume has been quantitated with computer-assisted analysis using a magnetic resonance imaging voxel-based specific regional analysis system developed for the study of Alzheimer disease (VSRAD), which yields a z score as the end point for assessment of hippocampal volume. The z score was higher in the high-HSCRP group than in the normal-HSCRP group (P < .0001). The fasting plasma glucose (P < .05) and insulin concentrations (P < .0001) and the homeostasis model assessment (HOMA) index (P < .0001) were higher in the high-HSCRP group than in the normal-HSCRP group. Multiple regression analysis showed that HSCRP levels were independently predicted by z score and HOMA index. Our results indicate that the elevated level of HSCRP in Japanese nondementia patients with type 2 diabetes mellitus is characterized by increased hippocampus volume and insulin resistance, and that the z score and HOMA index are independent predictors of HSCRP.
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Affiliation(s)
- Futoshi Anan
- Department of Cardiology, Oita Red Cross Hospital, Oita 870-0033, Japan.
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42
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Mielke JG, Wang YT. Insulin, synaptic function, and opportunities for neuroprotection. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:133-86. [PMID: 21199772 DOI: 10.1016/b978-0-12-385506-0.00004-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A steadily growing number of studies have begun to establish that the brain and insulin, while traditionally viewed as separate, do indeed have a relationship. The uptake of pancreatic insulin, along with neuronal biosynthesis, provides neural tissue with the hormone. As well, insulin acts upon a neuronal receptor that, although a close reflection of its peripheral counterpart, is characterized by unique structural and functional properties. One distinction is that the neural variant plays only a limited part in neuronal glucose transport. However, a number of other roles for neural insulin are gradually emerging; most significant among these is the modulation of ligand-gated ion channel (LGIC) trafficking. Notably, insulin has been shown to affect the tone of synaptic transmission by regulating cell-surface expression of inhibitory and excitatory receptors. The manner in which insulin regulates receptor movement may provide a cellular mechanism for insulin-mediated neuroprotection in the absence of hypoglycemia and stimulate the exploration of new therapeutic opportunities.
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Affiliation(s)
- John G Mielke
- Faculty of Applied Health Sciences, Department of Health Studies and Gerontology, University of Waterloo, Waterloo, Ontario, Canada
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43
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Bruehl H, Sweat V, Hassenstab J, Polyakov V, Convit A. Cognitive impairment in nondiabetic middle-aged and older adults is associated with insulin resistance. J Clin Exp Neuropsychol 2010; 32:487-93. [PMID: 20524222 DOI: 10.1080/13803390903224928] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
To determine whether the cognitive impairments observed in adults with type 2 diabetes mellitus (T2DM) exist in preclinical disease, we compared 38 adult participants with evidence of insulin resistance (IR) to 54 age-, gender-, and education-matched control participants on a battery of neuropsychological tests. We found that participants with IR had performance reductions in declarative memory and executive functioning. When we examined IR simultaneously with other biomedical indicators with which it co-occurs, only IR itself was associated with declarative memory, and hemoglobin A1c (HbA1c) was associated with executive functioning and working memory. We conclude that individuals with insulin resistance already demonstrate similar reductions in cognitive performance as those described in T2DM.
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Affiliation(s)
- H Bruehl
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
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44
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McEwen BS. Stress, sex, and neural adaptation to a changing environment: mechanisms of neuronal remodeling. Ann N Y Acad Sci 2010; 1204 Suppl:E38-59. [PMID: 20840167 PMCID: PMC2946089 DOI: 10.1111/j.1749-6632.2010.05568.x] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The adult brain is much more resilient and adaptable than previously believed, and adaptive structural plasticity involves growth and shrinkage of dendritic trees, turnover of synapses, and limited amounts of neurogenesis in the forebrain, especially the dentate gyrus of the hippocampal formation. Stress and sex hormones help to mediate adaptive structural plasticity, which has been extensively investigated in the hippocampus and to a lesser extent in the prefrontal cortex and amygdala, all brain regions that are involved in cognitive and emotional functions. Stress and sex hormones exert their effects on brain structural remodeling through both classical genomic as well as non-genomic mechanisms, and they do so in collaboration with neurotransmitters and other intra- and extracellular mediators. This review will illustrate the actions of estrogen on synapse formation in the hippocampus and the process of stress-induced remodeling of dendrites and synapses in the hippocampus, amygdala, and prefrontal cortex. The influence of early developmental epigenetic events, such as early life stress and brain sexual differentiation, is noted along with the interactions between sex hormones and the effects of stress on the brain. Because hormones influence brain structure and function and because hormone secretion is governed by the brain, applied molecular neuroscience techniques can begin to reveal the role of hormones in brain-related disorders and the treatment of these diseases. A better understanding of hormone-brain interactions should promote more flexible approaches to the treatment of psychiatric disorders, as well as their prevention through both behavioral and pharmaceutical interventions.
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Affiliation(s)
- Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, USA.
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45
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McNay EC, Ong CT, McCrimmon RJ, Cresswell J, Bogan JS, Sherwin RS. Hippocampal memory processes are modulated by insulin and high-fat-induced insulin resistance. Neurobiol Learn Mem 2010; 93:546-53. [PMID: 20176121 DOI: 10.1016/j.nlm.2010.02.002] [Citation(s) in RCA: 273] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 02/10/2010] [Accepted: 02/17/2010] [Indexed: 01/09/2023]
Abstract
Insulin regulates glucose uptake and storage in peripheral tissues, and has been shown to act within the hypothalamus to acutely regulate food intake and metabolism. The machinery for transduction of insulin signaling is also present in other brain areas, particularly in the hippocampus, but a physiological role for brain insulin outside the hypothalamus has not been established. Recent studies suggest that insulin may be able to modulate cognitive functions including memory. Here we report that local delivery of insulin to the rat hippocampus enhances spatial memory, in a PI-3-kinase dependent manner, and that intrahippocampal insulin also increases local glycolytic metabolism. Selective blockade of endogenous intrahippocampal insulin signaling impairs memory performance. Further, a rodent model of type 2 diabetes mellitus produced by a high-fat diet impairs basal cognitive function and attenuates both cognitive and metabolic responses to hippocampal insulin administration. Our data demonstrate that insulin is required for optimal hippocampal memory processing. Insulin resistance within the telencephalon may underlie the cognitive deficits commonly reported to accompany type 2 diabetes.
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Affiliation(s)
- Ewan C McNay
- Dept. of Psychology, University at Albany, Albany, NY 12222, USA.
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46
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The Brain-insulin Connection, Metabolic Diseases and Related Pathologies. DIABETES, INSULIN AND ALZHEIMER'S DISEASE 2010. [DOI: 10.1007/978-3-642-04300-0_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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47
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Zhao W, Wu X, Xie H, Ke Y, Yung WH. Permissive Role of Insulin in the Expression of Long-Term Potentiation in the Hippocampus of Immature Rats. Neurosignals 2010; 18:236-45. [DOI: 10.1159/000324040] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 12/30/2010] [Indexed: 01/21/2023] Open
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48
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Insulin-Mediated Neuroplasticity in the Central Nervous System. DIABETES, INSULIN AND ALZHEIMER'S DISEASE 2010. [DOI: 10.1007/978-3-642-04300-0_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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49
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Anan F, Masaki T, Shimomura T, Fujiki M, Umeno Y, Eshima N, Saikawa T, Yoshimatsu H. Abdominal visceral fat accumulation is associated with hippocampus volume in non-dementia patients with type 2 diabetes mellitus. Neuroimage 2010; 49:57-62. [DOI: 10.1016/j.neuroimage.2009.08.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 08/06/2009] [Accepted: 08/10/2009] [Indexed: 11/26/2022] Open
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50
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Insulin Action in the Brain and the Pathogenesis of Alzheimer’s Disease. DIABETES, INSULIN AND ALZHEIMER'S DISEASE 2010. [DOI: 10.1007/978-3-642-04300-0_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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