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Shypshyna M, Kolesnyk O, Fedulova S, Veselovsky N. Insulin modulates the paired-pulse plasticity at glutamatergic synapses of hippocampal neurons under hypoinsulinemia. Front Cell Neurosci 2023; 17:1132325. [PMID: 37025701 PMCID: PMC10072261 DOI: 10.3389/fncel.2023.1132325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 03/06/2023] [Indexed: 04/08/2023] Open
Abstract
Hypoinsulinemia is a pathological consequence of diabetes mellitus that can cause a number of complications of the central and peripheral nervous system. Dysfunction of signaling cascades of insulin receptors under insulin deficiency can contribute to the development of cognitive disorders associated with impaired synaptic plasticity properties. Earlier we have shown that hypoinsulinemia causes a shift of short-term plasticity in glutamatergic hippocampal synapses from facilitation to depression and apparently involves mechanisms of glutamate release probability reduction. Here we used the whole cell patch-clamp recording of evoked glutamatergic excitatory postsynaptic currents (eEPSCs) and the method of local extracellular electrical stimulation of a single presynaptic axon to investigate the effect of insulin (100 nM) on the paired-pulse plasticity at glutamatergic synapses of cultured hippocampal neurons under hypoinsulinemia. Our data indicate that under normoinsulinemia additional insulin enhances the paired-pulse facilitation (PPF) of eEPSCs in hippocampal neurons by stimulating the glutamate release in their synapses. Under hypoinsulinemia, insulin did not have a significant effect on the parameters of paired-pulse plasticity on neurons of PPF subgroup, which may indicate the development of insulin resistance, while the effect of insulin on PPD neurons indicates its ability to recover the form normoinsulinemia, including the increasing probability of plasticity to the control level in of glutamate release in their synapses.
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Hoirisch-Clapauch S. Mechanisms affecting brain remodeling in depression: do all roads lead to impaired fibrinolysis? Mol Psychiatry 2022; 27:525-533. [PMID: 34404914 DOI: 10.1038/s41380-021-01264-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/28/2021] [Accepted: 08/04/2021] [Indexed: 02/07/2023]
Abstract
Fibrinolysis occurs when plasminogen activators, such as tissue plasminogen activator (tPA), convert plasminogen to plasmin, which dissolves the fibrin clot. The proteolytic activity of tPA and plasmin is not restricted to fibrin degradation. In the extravascular space, these two proteases modify a variety of substrates other than fibrin, playing a crucial role in physiological and pathological tissue remodeling. In the brain, for example, tPA and plasmin mediate the conversion of brain-derived neurotrophic factor precursor (proBDNF) to mature brain-derived neurotrophic factor precursor (BDNF). Thus, the fibrinolytic system influences processes reported to be dysfunctional in depression, including neurogenesis, synaptic plasticity, and reward processing. The hypothesis that decreased fibrinolytic activity is an important element in the pathogenesis of depression is supported by the association between depression and increased levels of plasminogen activator inhibitor (PAI)-1, the main inhibitor of tPA. Also, various biochemical markers of depression induce PAI-1 synthesis, including hypercortisolism, hyperinsulinemia, hyperleptinemia, increased levels of cytokines, and hyperhomocysteinemia. Moreover, hypofibrinolysis provides a link between depression and emotional eating, binge eating, vegetarianism, and veganism. This paper discusses the role of reduced fibrinolytic activity in the bidirectional interplay between depression and its somatic manifestations and complications. It also reviews evidence that abnormal fibrinolysis links heterogeneous conditions associated with treatment-resistant depression. Understanding the role of hypofibrinolysis in depression may open new avenues for its treatment.
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Mahalakshmi B, Maurya N, Lee SD, Bharath Kumar V. Possible Neuroprotective Mechanisms of Physical Exercise in Neurodegeneration. Int J Mol Sci 2020; 21:ijms21165895. [PMID: 32824367 PMCID: PMC7460620 DOI: 10.3390/ijms21165895] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/13/2020] [Accepted: 08/15/2020] [Indexed: 12/22/2022] Open
Abstract
Physical exercise (PE) improves physical performance, mental status, general health, and well-being. It does so by affecting many mechanisms at the cellular and molecular level. PE is beneficial for people suffering from neuro-degenerative diseases because it improves the production of neurotrophic factors, neurotransmitters, and hormones. PE promotes neuronal survival and neuroplasticity and also optimizes neuroendocrine and physiological responses to psychosocial and physical stress. PE sensitizes the parasympathetic nervous system (PNS), Autonomic Nervous System (ANS) and central nervous system (CNS) by promoting many processes such as synaptic plasticity, neurogenesis, angiogenesis, and autophagy. Overall, it carries out many protective and preventive activities such as improvements in memory, cognition, sleep and mood; growth of new blood vessels in nervous system; and the reduction of stress, anxiety, neuro-inflammation, and insulin resistance. In the present work, the protective effects of PE were overviewed. Suitable examples from the current research work in this context are also given in the article.
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Affiliation(s)
- B. Mahalakshmi
- Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam;
| | - Nancy Maurya
- Department of Botany, Government Science College, Pandhurna, Chhindwara, Madhya Pradesh 480334, India;
| | - Shin-Da Lee
- Department of Physical Therapy, Asia University, Taichung 41354, Taiwan
- Department of Physical Therapy Graduate Institute of Rehabilitation Science, China Medical University, Taichung 40402, Taiwan
- Correspondence: (S.-D.L.); (V.B.K.); Tel.: +886-4-22053366 (ext. 7300) (S.-D.L.); +886-4-2332-3456 (ext. 6352 or 6353) (V.B.K.); Fax: 886-4-22065051 (S.-D.L.); +886-4-23305834 (V.B.K.)
| | - V. Bharath Kumar
- Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung 41354, Taiwan
- Correspondence: (S.-D.L.); (V.B.K.); Tel.: +886-4-22053366 (ext. 7300) (S.-D.L.); +886-4-2332-3456 (ext. 6352 or 6353) (V.B.K.); Fax: 886-4-22065051 (S.-D.L.); +886-4-23305834 (V.B.K.)
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4
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Spinelli M, Fusco S, Grassi C. Brain insulin resistance impairs hippocampal plasticity. VITAMINS AND HORMONES 2020; 114:281-306. [PMID: 32723548 DOI: 10.1016/bs.vh.2020.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nutrient-related signals have been demonstrated to influence brain development and cognitive functions. In particular, insulin signaling has been shown to impact on molecular cascades underlying hippocampal plasticity, learning and memory. Alteration of brain insulin signaling interferes with the maintenance of neural stem cell niche and neuronal activity in the hippocampus. Brain insulin resistance is also emerging as key factor causing the cognitive impairment observed in metabolic and neurodegenerative diseases. Here, we review the molecular mechanisms involved in the insulin modulation of both adult neurogenesis and synaptic activity in the hippocampus. We also summarize the effects of altered insulin sensitivity on hippocampal plasticity. Finally, we reassume the experimental and epidemiological evidence highlighting the critical role of brain insulin resistance at the crossroad between type 2 diabetes and Alzheimer's disease.
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Affiliation(s)
- Matteo Spinelli
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Salvatore Fusco
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
| | - Claudio Grassi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
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5
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Spinelli M, Fusco S, Grassi C. Brain Insulin Resistance and Hippocampal Plasticity: Mechanisms and Biomarkers of Cognitive Decline. Front Neurosci 2019; 13:788. [PMID: 31417349 PMCID: PMC6685093 DOI: 10.3389/fnins.2019.00788] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/15/2019] [Indexed: 12/27/2022] Open
Abstract
In the last decade, much attention has been devoted to the effects of nutrient-related signals on brain development and cognitive functions. A turning point was the discovery that brain areas other than the hypothalamus expressed receptors for hormones related to metabolism. In particular, insulin signaling has been demonstrated to impact on molecular cascades underlying hippocampal plasticity, learning and memory. Here, we summarize the molecular evidence linking alteration of hippocampal insulin sensitivity with changes of both adult neurogenesis and synaptic plasticity. We also review the epidemiological studies and experimental models emphasizing the critical role of brain insulin resistance at the crossroad between metabolic and neurodegenerative disease. Finally, we brief novel findings suggesting how biomarkers of brain insulin resistance, involving the study of brain-derived extracellular vesicles and brain glucose metabolism, may predict the onset and/or the progression of cognitive decline.
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Affiliation(s)
- Matteo Spinelli
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Salvatore Fusco
- Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
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Park HS, Park SS, Kim CJ, Shin MS, Kim TW. Exercise Alleviates Cognitive Functions by Enhancing Hippocampal Insulin Signaling and Neuroplasticity in High-Fat Diet-Induced Obesity. Nutrients 2019; 11:nu11071603. [PMID: 31311133 PMCID: PMC6683269 DOI: 10.3390/nu11071603] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 07/04/2019] [Accepted: 07/10/2019] [Indexed: 02/07/2023] Open
Abstract
Obesity, caused by a high-fat diet (HFD), leads to insulin resistance, which is a precursor of diabetes and a risk factor for impaired cognitive function, dementia, and brain diseases, such as Alzheimer’s disease. Physical exercise has positive effects on obesity and brain functions. We investigated whether the decline in cognitive function caused by a HFD could be improved through exercise by examining insulin signaling pathways and neuroplasticity in the hippocampus. Four-week-old C57BL/6 male mice were fed a HFD or a regular diet for 20 weeks, followed by 12 weeks of treadmill exercise. To ascertain the effects of treadmill exercise on impaired cognitive function caused by obesity, the present study implemented behavioral testing (Morris water maze, step-down). Moreover, insulin-signaling and neuroplasticity were measured in the hippocampus and dentate gyrus. Our results demonstrated that HFD-fed obesity-induced insulin resistance was improved by exercise. In addition, the HFD group showed a decrease in insulin signaling and neuroplasticity in the hippocampus and the dentate gyrus and increased cognitive function impairment, which were reversed by physical exercise. Overall, our findings indicate that physical exercise may act as a non-pharmacologic method that protects against cognitive dysfunction caused by obesity by improving hippocampal insulin signaling and neuroplasticity.
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Affiliation(s)
- Hye-Sang Park
- Department of Kinesiology, College of Public Health and Cardiovascular Research Center, Lewis Katz school of Medicine, Temple University, Philadelphia, PA 19122, USA
| | - Sang-Seo Park
- Department of Physiology, College of Medicine, KyungHee University, Seoul 02447, Korea
| | - Chang-Ju Kim
- Department of Physiology, College of Medicine, KyungHee University, Seoul 02447, Korea
| | - Mal-Soon Shin
- School of Global sport studies, Korea University, Sejong 30019, Korea
| | - Tae-Woon Kim
- Department of Physiology, College of Medicine, KyungHee University, Seoul 02447, Korea.
- Exercise Rehabilitation Research Institute, Department of Exercise & Health Science, Sangmyung University, Seoul 03016, Korea.
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Al Haj Ahmad RM, Al-Domi HA. Thinking about brain insulin resistance. Diabetes Metab Syndr 2018; 12:1091-1094. [PMID: 29778668 DOI: 10.1016/j.dsx.2018.05.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 05/04/2018] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Dementia and type 2 diabetes mellitus (T2DM) are two of the epidemics of our time; in which insulin resistance (IR) is playing the central role. Epidemiological studies found that different types of dementia development may be promoted by the presence of T2DM. OBJECTIVES We aimed in this review to highlight the role of insulin and the IR in the brain as a pathophysiological factor of dementia development and also to expand our understanding of T2DM as a mediator of IR in the brain and to review the possible mechanisms of action that may explain the association. METHODOLOGY A critical review of the relevant published English articles up to 2018, using PubMed, Google Scholar, Science Direct, ADI, and WHO database was carried out. Keywords were included insulin resistance, T3DM, T2DM, dementia, brain insulin resistance were used. CONCLUSION The rapidly increased prevalence of dementia concurrently with T2DM and obesity need urgent action to illustrate guidelines for prevention, modifying, and treatment based on mechanistic studies.
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Affiliation(s)
- Reem M Al Haj Ahmad
- Department of Nutrition and Food Technology, Faculty of Agriculture, The University of Jordan, Queen Rania Street, Amman 11942, Jordan
| | - Hayder A Al-Domi
- Department of Nutrition and Food Technology, Faculty of Agriculture, The University of Jordan, Queen Rania Street, Amman 11942, Jordan.
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Eckstrand KL, Mummareddy N, Kang H, Cowan R, Zhou M, Zald D, Silver HJ, Niswender KD, Avison MJ. An insulin resistance associated neural correlate of impulsivity in type 2 diabetes mellitus. PLoS One 2017; 12:e0189113. [PMID: 29228027 PMCID: PMC5724830 DOI: 10.1371/journal.pone.0189113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 11/20/2017] [Indexed: 02/06/2023] Open
Abstract
Central insulin resistance (IR) influences striatal dopamine (DA) tone, an important determinant of behavioral self-regulation. We hypothesized that an association exists between the degree of peripheral IR and impulse control, mediated by the impact of IR on brain circuits controlling the speed of executing “go” and/or “stop” responses. We measured brain activation and associated performance on a stop signal task (SST) in obese adults with type 2 diabetes (age, 48.1 ± 6.9 yrs (mean ± SD); BMI, 36.5 ± 4.0 kg/m2; HOMA-IR, 7.2 ± 4.1; 12 male, 18 female). Increasing IR, but not BMI, was a predictor of shorter critical stop signal delay (cSSD), a measure of the time window during which a go response can be successfully countermanded (R2 = 0.12). This decline was explained by an IR-associated increase in go speed (R2 = 0.13) with little impact of IR or BMI on stop speed. Greater striatal fMRI activation contrast in stop error (SE) compared with stop success (SS) trials (CONSE>SS) was a significant predictor of faster go speeds (R2 = 0.33, p = 0.002), and was itself predicted by greater IR (CONSE>SS vs HOMA-IR: R2 = 0.10, p = 0.04). Furthermore, this impact of IR on striatal activation was a significant mediator of the faster go speeds and greater impulsivity observed with greater IR. These findings suggest a neural mechanism by which IR may increase impulsivity and degrade behavioral self-regulation.
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Affiliation(s)
- Kristen L. Eckstrand
- Department of Radiology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Nishit Mummareddy
- Department of Radiology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Hakmook Kang
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Ronald Cowan
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Minchun Zhou
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - David Zald
- Department of Psychology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Heidi J. Silver
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Kevin D. Niswender
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Malcolm J. Avison
- Department of Radiology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- * E-mail:
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9
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Neth BJ, Craft S. Insulin Resistance and Alzheimer's Disease: Bioenergetic Linkages. Front Aging Neurosci 2017; 9:345. [PMID: 29163128 PMCID: PMC5671587 DOI: 10.3389/fnagi.2017.00345] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 10/13/2017] [Indexed: 12/14/2022] Open
Abstract
Metabolic dysfunction is a well-established feature of Alzheimer's disease (AD), evidenced by brain glucose hypometabolism that can be observed potentially decades prior to the development of AD symptoms. Furthermore, there is mounting support for an association between metabolic disease and the development of AD and related dementias. Individuals with insulin resistance, type 2 diabetes mellitus (T2D), hyperlipidemia, obesity, or other metabolic disease may have increased risk for the development of AD and similar conditions, such as vascular dementia. This association may in part be due to the systemic mitochondrial dysfunction that is common to these pathologies. Accumulating evidence suggests that mitochondrial dysfunction is a significant feature of AD and may play a fundamental role in its pathogenesis. In fact, aging itself presents a unique challenge due to inherent mitochondrial dysfunction and prevalence of chronic metabolic disease. Despite the progress made in understanding the pathogenesis of AD and in the development of potential therapies, at present we remain without a disease-modifying treatment. In this review, we will discuss insulin resistance as a contributing factor to the pathogenesis of AD, as well as the metabolic and bioenergetic disruptions linking insulin resistance and AD. We will also focus on potential neuroimaging tools for the study of the metabolic dysfunction commonly seen in AD with hopes of developing therapeutic and preventative targets.
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Affiliation(s)
- Bryan J Neth
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Suzanne Craft
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States
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10
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Terraneo L, Samaja M. Comparative Response of Brain to Chronic Hypoxia and Hyperoxia. Int J Mol Sci 2017; 18:ijms18091914. [PMID: 28880206 PMCID: PMC5618563 DOI: 10.3390/ijms18091914] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/01/2017] [Accepted: 09/03/2017] [Indexed: 12/25/2022] Open
Abstract
Two antithetic terms, hypoxia and hyperoxia, i.e., insufficient and excess oxygen availability with respect to needs, are thought to trigger opposite responses in cells and tissues. This review aims at summarizing the molecular and cellular mechanisms underlying hypoxia and hyperoxia in brain and cerebral tissue, a context that may prove to be useful for characterizing not only several clinically relevant aspects, but also aspects related to the evolution of oxygen transport and use by the tissues. While the response to acute hypoxia/hyperoxia presumably recruits only a minor portion of the potentially involved cell machinery, focusing into chronic conditions, instead, enables to take into consideration a wider range of potential responses to oxygen-linked stress, spanning from metabolic to genic. We will examine how various brain subsystems, including energetic metabolism, oxygen sensing, recruitment of pro-survival pathways as protein kinase B (Akt), mitogen-activated protein kinases (MAPK), neurotrophins (BDNF), erythropoietin (Epo) and its receptors (EpoR), neuroglobin (Ngb), nitric oxide (NO), carbon monoxide (CO), deal with chronic hypoxia and hyperoxia to end-up with the final outcomes, oxidative stress and brain damage. A more complex than expected pattern results, which emphasizes the delicate balance between the severity of the stress imposed by hypoxia and hyperoxia and the recruitment of molecular and cellular defense patterns. While for certain functions the expectation that hypoxia and hyperoxia should cause opposite responses is actually met, for others it is not, and both emerge as dangerous treatments.
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Affiliation(s)
- Laura Terraneo
- Department of Health Science, University of Milan, I-20142 Milano, Italy.
| | - Michele Samaja
- Department of Health Science, University of Milan, I-20142 Milano, Italy.
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11
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Small DM. Dopamine Adaptations as a Common Pathway for Neurocognitive Impairment in Diabetes and Obesity: A Neuropsychological Perspective. Front Neurosci 2017; 11:134. [PMID: 28400713 PMCID: PMC5368264 DOI: 10.3389/fnins.2017.00134] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/06/2017] [Indexed: 01/06/2023] Open
Abstract
Evidence accumulates linking obesity and diabetes with cognitive dysfunction. At present the mechanism(s) underlying these associations and the relative contribution of diet, adiposity, and metabolic dysfunction are unknown. In this perspective key gaps in knowledge are outlined and an initial sketch of a neuropsychological profile is developed that points toward a critical role for dopamine (DA) adaptations in neurocognitive impairment secondary to diabetes and obesity. The precise mechanisms by which diet, metabolic dysfunction, and adiposity influence the DA system to impact cognition remains unclear and is an important direction for future research.
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Affiliation(s)
- Dana M Small
- The John B Pierce LaboratoryNew Haven, CT, USA; Department of Psychiatry, Yale University School of MedicineNew Haven, CT, USA
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12
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Caron A, Richard D. Neuronal systems and circuits involved in the control of food intake and adaptive thermogenesis. Ann N Y Acad Sci 2016; 1391:35-53. [PMID: 27768821 DOI: 10.1111/nyas.13263] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 08/18/2016] [Accepted: 08/24/2016] [Indexed: 12/27/2022]
Abstract
With the still-growing prevalence of obesity worldwide, major efforts are made to understand the various behavioral, environmental, and genetic factors that promote excess fat gain. Obesity results from an imbalance between energy intake and energy expenditure, which emphasizes the importance of deciphering the mechanisms behind energy balance regulation to understand its physiopathology. The control of energy balance is assured by brain systems/circuits capable of generating adequate ingestive and thermogenic responses to maintain the stability of energy reserves, which implies a proper integration of the homeostatic signals that inform about the status of the energy stores. In this article, we overview the organization and functionality of key neuronal circuits or pathways involved in the control of food intake and energy expenditure. We review the role of the corticolimbic (executive and reward) and autonomic systems that integrate their activities to regulate energy balance. We also describe the mechanisms and pathways whereby homeostatic sensing is achieved in response to variations of homeostatic hormones, such as leptin, insulin, and ghrelin, while putting some emphasis on the prominent importance of the mechanistic target of the rapamycin signaling pathway in coordinating the homeostatic sensing process.
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Affiliation(s)
- Alexandre Caron
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec and Faculty of Medicine, Department of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Denis Richard
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec and Faculty of Medicine, Department of Medicine, Université Laval, Quebec City, Quebec, Canada
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13
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Ribarič S. The Rationale for Insulin Therapy in Alzheimer's Disease. Molecules 2016; 21:molecules21060689. [PMID: 27240327 PMCID: PMC6273626 DOI: 10.3390/molecules21060689] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/14/2016] [Accepted: 05/19/2016] [Indexed: 12/30/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia, with a prevalence that increases with age. By 2050, the worldwide number of patients with AD is projected to reach more than 140 million. The prominent signs of AD are progressive memory loss, accompanied by a gradual decline in cognitive function and premature death. AD is the clinical manifestation of altered proteostasis. The initiating step of altered proteostasis in most AD patients is not known. The progression of AD is accelerated by several chronic disorders, among which the contribution of diabetes to AD is well understood at the cell biology level. The pathological mechanisms of AD and diabetes interact and tend to reinforce each other, thus accelerating cognitive impairment. At present, only symptomatic interventions are available for treating AD. To optimise symptomatic treatment, a personalised therapy approach has been suggested. Intranasal insulin administration seems to open the possibility for a safe, and at least in the short term, effective symptomatic intervention that delays loss of cognition in AD patients. This review summarizes the interactions of AD and diabetes from the cell biology to the patient level and the clinical results of intranasal insulin treatment of cognitive decline in AD.
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Affiliation(s)
- Samo Ribarič
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia.
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14
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Dornellas APS, Watanabe RLH, Pimentel GD, Boldarine VT, Nascimento CMO, Oyama LM, Ghebremeskel K, Wang Y, Bueno AA, Ribeiro EB. Deleterious effects of lard-enriched diet on tissues fatty acids composition and hypothalamic insulin actions. Prostaglandins Leukot Essent Fatty Acids 2015; 102-103:21-9. [PMID: 26525379 DOI: 10.1016/j.plefa.2015.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 08/28/2015] [Accepted: 10/01/2015] [Indexed: 01/14/2023]
Abstract
Altered tissue fatty acid (FA) composition may affect mechanisms involved in the control of energy homeostasis, including central insulin actions. In rats fed either standard chow or a lard-enriched chow (high in saturated/low in polyunsaturated FA, HS-LP) for eight weeks, we examined the FA composition of blood, hypothalamus, liver, and retroperitoneal, epididymal and mesenteric adipose tissues. Insulin-induced hypophagia and hypothalamic signaling were evaluated after intracerebroventricular insulin injection. HS-LP feeding increased saturated FA content in adipose tissues and serum while it decreased polyunsaturated FA content of adipose tissues, serum, and liver. Hypothalamic C20:5n-3 and C20:3n-6 contents increased while monounsaturated FA content decreased. HS-LP rats showed hyperglycemia, impaired insulin-induced hypophagia and hypothalamic insulin signaling. The results showed that, upon HS-LP feeding, peripheral tissues underwent potentially deleterious alterations in their FA composition, whist the hypothalamus was relatively preserved. However, hypothalamic insulin signaling and hypophagia were drastically impaired. These findings suggest that impairment of hypothalamic insulin actions by HS-LP feeding was not related to tissue FA composition.
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Affiliation(s)
- A P S Dornellas
- Department of Physiology, Division of Nutrition Physiology, Sao Paulo Federal University, Sao Paulo, Brazil
| | - R L H Watanabe
- Department of Physiology, Division of Nutrition Physiology, Sao Paulo Federal University, Sao Paulo, Brazil
| | - G D Pimentel
- Department of Physiology, Division of Nutrition Physiology, Sao Paulo Federal University, Sao Paulo, Brazil
| | - V T Boldarine
- Department of Physiology, Division of Nutrition Physiology, Sao Paulo Federal University, Sao Paulo, Brazil
| | - C M O Nascimento
- Department of Physiology, Division of Nutrition Physiology, Sao Paulo Federal University, Sao Paulo, Brazil
| | - L M Oyama
- Department of Physiology, Division of Nutrition Physiology, Sao Paulo Federal University, Sao Paulo, Brazil
| | - K Ghebremeskel
- Lipidomics and Nutrition Research Centre, Faculty of Life Sciences and Computing, London Metropolitan University, London, United Kingdom
| | - Y Wang
- Department of Medicine, Division of Infectious Diseases, Section of Paediatrics, Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
| | - A A Bueno
- Institute of Science and the Environment, University of Worcester, Worcester, United Kingdom
| | - E B Ribeiro
- Department of Physiology, Division of Nutrition Physiology, Sao Paulo Federal University, Sao Paulo, Brazil.
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Heni M, Kullmann S, Preissl H, Fritsche A, Häring HU. Impaired insulin action in the human brain: causes and metabolic consequences. Nat Rev Endocrinol 2015; 11:701-11. [PMID: 26460339 DOI: 10.1038/nrendo.2015.173] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Over the past few years, evidence has accumulated that the human brain is an insulin-sensitive organ. Insulin regulates activity in a limited number of specific brain areas that are important for memory, reward, eating behaviour and the regulation of whole-body metabolism. Accordingly, insulin in the brain modulates cognition, food intake and body weight as well as whole-body glucose, energy and lipid metabolism. However, brain imaging studies have revealed that not everybody responds equally to insulin and that a substantial number of people are brain insulin resistant. In this Review, we provide an overview of the effects of insulin in the brain in humans and the relevance of the effects for physiology. We present emerging evidence for insulin resistance of the human brain. Factors associated with brain insulin resistance such as obesity and increasing age, as well as possible pathogenic factors such as visceral fat, saturated fatty acids, alterations at the blood-brain barrier and certain genetic polymorphisms, are reviewed. In particular, the metabolic consequences of brain insulin resistance are discussed and possible future approaches to overcome brain insulin resistance and thereby prevent or treat obesity and type 2 diabetes mellitus are outlined.
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Affiliation(s)
- Martin Heni
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
| | - Stephanie Kullmann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
| | - Hubert Preissl
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
| | - Andreas Fritsche
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
| | - Hans-Ulrich Häring
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
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Brain signaling systems in the Type 2 diabetes and metabolic syndrome: promising target to treat and prevent these diseases. Future Sci OA 2015; 1:FSO25. [PMID: 28031898 PMCID: PMC5137856 DOI: 10.4155/fso.15.23] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The changes in the brain signaling systems play an important role in etiology and pathogenesis of Type 2 diabetes mellitus (T2DM) and metabolic syndrome (MS), being a possible cause of these diseases. Therefore, their restoration at the early stages of T2DM and MS can be regarded as a promising way to treat and prevent these diseases and their complications. The data on the functional state of the brain signaling systems regulated by insulin, IGF-1, leptin, dopamine, serotonin, melanocortins and glucagon-like peptide-1, in T2DM and MS, are analyzed. The pharmacological approaches to restoration of these systems and improvement of insulin sensitivity, energy expenditure, lipid metabolism, and to prevent diabetic complications are discussed.
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Preferential reduction of synaptic efficacy in the dentate gyrus of hippocampal slices from aged rats during reduced glucose availability. Neuroscience 2015; 307:262-72. [DOI: 10.1016/j.neuroscience.2015.08.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/26/2015] [Accepted: 08/27/2015] [Indexed: 11/18/2022]
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Heni M, Kullmann S, Gallwitz B, Häring HU, Preissl H, Fritsche A. Dissociation of GLP-1 and insulin association with food processing in the brain: GLP-1 sensitivity despite insulin resistance in obese humans. Mol Metab 2015; 4:971-6. [PMID: 26909313 PMCID: PMC4731733 DOI: 10.1016/j.molmet.2015.09.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 09/10/2015] [Accepted: 09/16/2015] [Indexed: 12/15/2022] Open
Abstract
Objective Glucagon-like peptide-1 (GLP-1) is released into the bloodstream after food intake. In addition to stimulating insulin release, it causes satiety and contributes to the termination of food intake. In this study, we investigated whether endogenous GLP-1 affects food-related brain activity and hunger. Methods Twenty-four volunteers (12 lean; 12 obese) underwent a 75 g oral glucose tolerance test that promotes GLP-1 secretion. Food cue-induced brain activity was assessed by functional magnetic resonance imaging and GLP-1 concentrations were measured before, 30, and 120 min after glucose intake. Results The significant increase in GLP-1 levels negatively correlated with a change in the food cue-induced brain activity in the orbitofrontal cortex, a major reward area. This association was independent of simultaneous alterations in insulin and glucose concentrations. The association was present in lean and overweight participants. By contrast, postprandial insulin changes were associated with orbitofrontal activations in lean individuals only. Conclusions The postprandial release of GLP-1 might alter reward processes in the orbitofrontal cortex and might thereby support the termination of food intake and reduce hunger. While obese persons showed brain insulin resistance, no GLP-1 resistance was observed. Our study provides novel insight into the central regulation of food intake by the incretin hormone GLP-1. GLP-1 levels associate with food cue-induced brain activity in the orbitofrontal cortex, a major reward area. While obese persons are brain insulin-resistant in the orbitofrontal cortex, they still respond to GLP-1. Postprandial GLP-1 release may alter reward processes in the orbitofrontal cortex to support the termination of food intake.
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Affiliation(s)
- Martin Heni
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
| | - Stephanie Kullmann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
| | - Baptist Gallwitz
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Hans-Ulrich Häring
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
| | - Hubert Preissl
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
| | - Andreas Fritsche
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
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Zhang Z, Fang P, Shi M, Zhu Y, Bo P. Elevated galanin may predict the risk of type 2 diabetes mellitus for development of Alzheimer's disease. Mech Ageing Dev 2015; 150:20-6. [PMID: 26253934 DOI: 10.1016/j.mad.2015.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/23/2015] [Accepted: 08/02/2015] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease is the most common form of dementia among the elderly and is characterized by progressive loss of memory and cognition. Epidemiological and clinical studies demonstrated that type 2 diabetes mellitus is an important risk factor for the development of Alzheimer's disease, i.e., the patients with type 2 diabetes mellitus are frequently companied with Alzheimer's disease symptoms. Despite many studies recently probed into the comorbid state of both diseases, so far the precise mechanism for this association is poorly understood. Emerging evidences suggest that defects in galanin play a central role on type 2 diabetes mellitus and is considered to be a risk factor for Alzheimer's disease development. This review provides a new insight into the multivariate relationship among galanin, type 2 diabetes mellitus and Alzheimer's disease, highlighting the effect of galanin system on the cross-talk between both diseases in human and rodent models. The current data support that activating central GalR2 attenuates insulin resistance and Alzheimer's disease feature in animal models. These may help us better understanding the pathogenesis of both diseases and provide useful hints for the development of novel therapeutic approaches to treat type 2 diabetes mellitus and Alzheimer's disease.
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Affiliation(s)
- Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Penghua Fang
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China; Department of Physiology, Nanjing University of Chinese Medicine Hanlin College, Taizhou 225300, China
| | - Mingyi Shi
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Yan Zhu
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Ping Bo
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China.
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20
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Lacroix MC, Caillol M, Durieux D, Monnerie R, Grebert D, Pellerin L, Repond C, Tolle V, Zizzari P, Baly C. Long-Lasting Metabolic Imbalance Related to Obesity Alters Olfactory Tissue Homeostasis and Impairs Olfactory-Driven Behaviors. Chem Senses 2015. [PMID: 26209545 DOI: 10.1093/chemse/bjv039] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Obesity is associated with chronic food intake disorders and binge eating. Food intake relies on the interaction between homeostatic regulation and hedonic signals among which, olfaction is a major sensory determinant. However, its potential modulation at the peripheral level by a chronic energy imbalance associated to obese status remains a matter of debate. We further investigated the olfactory function in a rodent model relevant to the situation encountered in obese humans, where genetic susceptibility is juxtaposed on chronic eating disorders. Using several olfactory-driven tests, we compared the behaviors of obesity-prone Sprague-Dawley rats (OP) fed with a high-fat/high-sugar diet with those of obese-resistant ones fed with normal chow. In OP rats, we reported 1) decreased odor threshold, but 2) poor olfactory performances, associated with learning/memory deficits, 3) decreased influence of fasting, and 4) impaired insulin control on food seeking behavior. Associated with these behavioral modifications, we found a modulation of metabolism-related factors implicated in 1) electrical olfactory signal regulation (insulin receptor), 2) cellular dynamics (glucorticoids receptors, pro- and antiapoptotic factors), and 3) homeostasis of the olfactory mucosa and bulb (monocarboxylate and glucose transporters). Such impairments might participate to the perturbed daily food intake pattern that we observed in obese animals.
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Affiliation(s)
| | - Monique Caillol
- INRA, UR1197, Neurobiologie de l'Olfaction, 78350 Jouy-en-Josas, France
| | - Didier Durieux
- INRA, UR1197, Neurobiologie de l'Olfaction, 78350 Jouy-en-Josas, France
| | - Régine Monnerie
- INRA, UR1197, Neurobiologie de l'Olfaction, 78350 Jouy-en-Josas, France
| | - Denise Grebert
- INRA, UR1197, Neurobiologie de l'Olfaction, 78350 Jouy-en-Josas, France
| | - Luc Pellerin
- Department of Physiology, University of Lausanne, CH1005 Lausanne, Switzerland and
| | - Cendrine Repond
- Department of Physiology, University of Lausanne, CH1005 Lausanne, Switzerland and
| | - Virginie Tolle
- UMR-S 894 INSERM, Centre de Psychiatrie et Neurosciences, Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Philippe Zizzari
- UMR-S 894 INSERM, Centre de Psychiatrie et Neurosciences, Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Christine Baly
- INRA, UR1197, Neurobiologie de l'Olfaction, 78350 Jouy-en-Josas, France
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Vandal M, Bourassa P, Calon F. Can insulin signaling pathways be targeted to transport Aβ out of the brain? Front Aging Neurosci 2015; 7:114. [PMID: 26136681 PMCID: PMC4468380 DOI: 10.3389/fnagi.2015.00114] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 05/29/2015] [Indexed: 12/11/2022] Open
Abstract
Although the causal role of Amyloid-β (Aβ) in Alzheimer’s disease (AD) is unclear, it is still reasonable to expect that lowering concentrations of Aβ in the brain may decrease the risk of developing the neurocognitive symptoms of the disease. Brain capillary endothelial cells forming the blood-brain barrier (BBB) express transporters regulating the efflux of Aβ out of the cerebral tissue. Age-related BBB dysfunctions, that have been identified in AD patients, might impair Aβ clearance from the brain. Thus, targeting BBB outward transport systems has been suggested as a way to stimulate the clearance of Aβ from the brain. Recent data indicate that the increase in soluble brain Aβ and behavioral impairments in 3×Tg-AD mice generated by months of intake of a high-fat diet can be acutely reversed by the administration of a single dose of insulin. A concomitant increase in plasma Aβ suggests that clearance from the brain through the BBB is a likely mechanism for this rapid effect of insulin. Here, we review how BBB insulin response pathways could be stimulated to decrease brain Aβ concentrations and improve cognitive performance, at least on the short term.
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Affiliation(s)
- Milene Vandal
- Faculté de Pharmacie, Université Laval Quebec, QC, Canada ; Axe Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUL) Québec, QC, Canada ; Institut des Nutraceutiques et des Aliments Fonctionnels, Université Laval Québec, QC, Canada
| | - Philippe Bourassa
- Faculté de Pharmacie, Université Laval Quebec, QC, Canada ; Axe Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUL) Québec, QC, Canada ; Institut des Nutraceutiques et des Aliments Fonctionnels, Université Laval Québec, QC, Canada
| | - Frédéric Calon
- Faculté de Pharmacie, Université Laval Quebec, QC, Canada ; Axe Neurosciences, Centre de Recherche du Centre Hospitalier de l'Université Laval (CHUL) Québec, QC, Canada ; Institut des Nutraceutiques et des Aliments Fonctionnels, Université Laval Québec, QC, Canada
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Gancheva S, Koliaki C, Bierwagen A, Nowotny P, Heni M, Fritsche A, Häring HU, Szendroedi J, Roden M. Effects of intranasal insulin on hepatic fat accumulation and energy metabolism in humans. Diabetes 2015; 64:1966-75. [PMID: 25576060 DOI: 10.2337/db14-0892] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 01/07/2015] [Indexed: 11/13/2022]
Abstract
Studies in rodents suggest that insulin controls hepatic glucose metabolism through brain-liver crosstalk, but human studies using intranasal insulin to mimic central insulin delivery have provided conflicting results. In this randomized controlled crossover trial, we investigated the effects of intranasal insulin on hepatic insulin sensitivity (HIS) and energy metabolism in 10 patients with type 2 diabetes and 10 lean healthy participants (CON). Endogenous glucose production was monitored with [6,6-(2)H2]glucose, hepatocellular lipids (HCLs), ATP, and inorganic phosphate concentrations with (1)H/(31)P magnetic resonance spectroscopy. Intranasal insulin transiently increased serum insulin levels followed by a gradual lowering of blood glucose in CON only. Fasting HIS index was not affected by intranasal insulin in CON and patients. HCLs decreased by 35% in CON only, whereas absolute hepatic ATP concentration increased by 18% after 3 h. A subgroup of CON received intravenous insulin to mimic the changes in serum insulin and blood glucose levels observed after intranasal insulin. This resulted in a 34% increase in HCLs without altering hepatic ATP concentrations. In conclusion, intranasal insulin does not affect HIS but rapidly improves hepatic energy metabolism in healthy humans, which is independent of peripheral insulinemia. These effects are blunted in patients with type 2 diabetes.
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Affiliation(s)
- Sofiya Gancheva
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Düsseldorf, Germany
| | - Chrysi Koliaki
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Düsseldorf, Germany
| | - Alessandra Bierwagen
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Düsseldorf, Germany
| | - Peter Nowotny
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Düsseldorf, Germany
| | - Martin Heni
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen (Paul Langerhans Institute Tübingen), Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Partner Neuherberg, Neuherberg, Germany
| | - Andreas Fritsche
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen (Paul Langerhans Institute Tübingen), Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Partner Neuherberg, Neuherberg, Germany
| | - Hans-Ulrich Häring
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen (Paul Langerhans Institute Tübingen), Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Partner Neuherberg, Neuherberg, Germany
| | - Julia Szendroedi
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Düsseldorf, Germany Department of Endocrinology and Diabetology, University Hospital, Düsseldorf, Germany
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Düsseldorf, Germany Department of Endocrinology and Diabetology, University Hospital, Düsseldorf, Germany
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Sartorius T, Peter A, Heni M, Maetzler W, Fritsche A, Häring HU, Hennige AM. The brain response to peripheral insulin declines with age: a contribution of the blood-brain barrier? PLoS One 2015; 10:e0126804. [PMID: 25965336 PMCID: PMC4429020 DOI: 10.1371/journal.pone.0126804] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 04/07/2015] [Indexed: 01/26/2023] Open
Abstract
Objectives It is a matter of debate whether impaired insulin action originates from a defect at the neural level or impaired transport of the hormone into the brain. In this study, we aimed to investigate the effect of aging on insulin concentrations in the periphery and the central nervous system as well as its impact on insulin-dependent brain activity. Methods Insulin, glucose and albumin concentrations were determined in 160 paired human serum and cerebrospinal fluid (CSF) samples. Additionally, insulin was applied in young and aged mice by subcutaneous injection or intracerebroventricularly to circumvent the blood-brain barrier. Insulin action and cortical activity were assessed by Western blotting and electrocorticography radiotelemetric measurements. Results In humans, CSF glucose and insulin concentrations were tightly correlated with the respective serum/plasma concentrations. The CSF/serum ratio for insulin was reduced in older subjects while the CSF/serum ratio for albumin increased with age like for most other proteins. Western blot analysis in murine whole brain lysates revealed impaired phosphorylation of AKT (P-AKT) in aged mice following peripheral insulin stimulation whereas P-AKT was comparable to levels in young mice after intracerebroventricular insulin application. As readout for insulin action in the brain, insulin-mediated cortical brain activity instantly increased in young mice subcutaneously injected with insulin but was significantly reduced and delayed in aged mice during the treatment period. When insulin was applied intracerebroventricularly into aged animals, brain activity was readily improved. Conclusions This study discloses age-dependent changes in insulin CSF/serum ratios in humans. In the elderly, cerebral insulin resistance might be partially attributed to an impaired transport of insulin into the central nervous system.
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Affiliation(s)
- Tina Sartorius
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tuebingen, Tuebingen, Germany
- German Center for Diabetes Research (DZD), Tuebingen, Germany
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany
- * E-mail:
| | - Andreas Peter
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tuebingen, Tuebingen, Germany
- German Center for Diabetes Research (DZD), Tuebingen, Germany
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany
| | - Martin Heni
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tuebingen, Tuebingen, Germany
- German Center for Diabetes Research (DZD), Tuebingen, Germany
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany
| | - Walter Maetzler
- Department of Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tuebingen, Germany
| | - Andreas Fritsche
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tuebingen, Tuebingen, Germany
- German Center for Diabetes Research (DZD), Tuebingen, Germany
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany
| | - Hans-Ulrich Häring
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tuebingen, Tuebingen, Germany
- German Center for Diabetes Research (DZD), Tuebingen, Germany
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany
| | - Anita M. Hennige
- German Center for Diabetes Research (DZD), Tuebingen, Germany
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany
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24
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Heni M, Wagner R, Kullmann S, Veit R, Mat Husin H, Linder K, Benkendorff C, Peter A, Stefan N, Häring HU, Preissl H, Fritsche A. Central insulin administration improves whole-body insulin sensitivity via hypothalamus and parasympathetic outputs in men. Diabetes 2014; 63:4083-8. [PMID: 25028522 DOI: 10.2337/db14-0477] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Animal studies suggest that insulin action in the brain is involved in the regulation of peripheral insulin sensitivity. Whether this holds true in humans is unknown. Using intranasal application of insulin to the human brain, we studied the impacts of brain insulin action on whole-body insulin sensitivity and the mechanisms involved in this process. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic glucose clamp before and after intranasal application of insulin and placebo in randomized order in lean and obese men. After insulin spray application in lean subjects, a higher glucose infusion rate was necessary to maintain euglycemia compared with placebo. Accordingly, clamp-derived insulin sensitivity index improved after insulin spray. In obese subjects, this insulin-sensitizing effect could not be detected. Change in the high-frequency band of heart rate variability, an estimate of parasympathetic output, correlated positively with change in whole-body insulin sensitivity after intranasal insulin. Improvement in whole-body insulin sensitivity correlated with the change in hypothalamic activity as assessed by functional magnetic resonance imaging. Intranasal insulin improves peripheral insulin sensitivity in lean but not in obese men. Furthermore, brain-derived peripheral insulin sensitization is associated with hypothalamic activity and parasympathetic outputs. Thus, the findings provide novel insights into the regulation of insulin sensitivity and the pathogenesis of insulin resistance in humans.
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Affiliation(s)
- Martin Heni
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Robert Wagner
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Stephanie Kullmann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany Institute of Medical Psychology and Behavioral Neurobiology/fMEG Center, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Ralf Veit
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany Institute of Medical Psychology and Behavioral Neurobiology/fMEG Center, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Haliza Mat Husin
- Institute of Medical Psychology and Behavioral Neurobiology/fMEG Center, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Katarzyna Linder
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Charlotte Benkendorff
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas Peter
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Norbert Stefan
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Hans-Ulrich Häring
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Hubert Preissl
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany Institute of Medical Psychology and Behavioral Neurobiology/fMEG Center, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas Fritsche
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
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Heni M, Schöpfer P, Peter A, Sartorius T, Fritsche A, Synofzik M, Häring HU, Maetzler W, Hennige AM. Evidence for altered transport of insulin across the blood-brain barrier in insulin-resistant humans. Acta Diabetol 2014; 51:679-81. [PMID: 24370925 DOI: 10.1007/s00592-013-0546-y] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 12/10/2013] [Indexed: 11/26/2022]
Abstract
Eating behavior, body weight regulation, peripheral glucose metabolism, and cognitive function depend on adequate insulin action in the brain, and recent studies in humans suggested that impaired insulin action in the brain emerges upon fat intake, obesity, and genetic variants. As insulin enters into the brain in a receptor-mediated fashion, we hypothesized that whole-body insulin sensitivity might affect the transport of insulin into the brain and contribute to the aversive effect of insulin resistance in the central nervous system. In this study, we aimed to determine the ratio of insulin in the cerebrospinal fluid and serum to whole-body insulin sensitivity. Healthy human subjects participated in an oral glucose tolerance test to determine whole-body insulin sensitivity and underwent lumbar puncture. Blood and CSF concentrations of insulin were significantly correlated. The CSF/serum ratio for insulin was significantly associated with whole body insulin sensitivity with reduced insulin transported into the CSF in insulin-resistant subjects. Together, our data suggest that transport of insulin into the CSF relates to peripheral insulin sensitivity and impairs insulin action in the brain. This underlines the need for sensitizing measures in insulin-resistant subjects.
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Affiliation(s)
- Martin Heni
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Eberhard Karls University, Tübingen, Germany
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Lee HK. Advances around technologies investigating mitochondrial function and insights gained by their applications. J Diabetes Investig 2014; 5:144-6. [PMID: 24843752 PMCID: PMC4023575 DOI: 10.1111/jdi.12221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 12/03/2022] Open
Affiliation(s)
- Hong Kyu Lee
- Department of Internal Medicine Eulji University and Eulji Hospital Seoul Korea
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Ong QR, Chan ES, Lim ML, Wong BS. Expression of human apolipoprotein E4 reduces insulin-receptor substrate 1 expression and Akt phosphorylation in the ageing liver. FEBS Open Bio 2014; 4:260-5. [PMID: 24649407 PMCID: PMC3958919 DOI: 10.1016/j.fob.2014.02.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 02/06/2014] [Accepted: 02/24/2014] [Indexed: 12/21/2022] Open
Abstract
Emerging studies suggest that ApoE has other functions beyond cholesterol metabolism. At 32-weeks, insulin signaling was similar in both ApoE3 and ApoE4 knock-in mice. At 72-weeks, IRS1 and PI3K expression and Akt phosphorylation were reduced in ApoE4 mice. Aged huApoE4 mice also have lower liver insulin but higher glucose content. This shows an ApoE genotype-dependent effect on liver insulin signaling during ageing.
The diabetic drug rosiglitazone was reported to improve glucose tolerance in insulin-resistant ApoE3 but not ApoE4 knock-in mice. We therefore examined whether apolipoprotein E (ApoE) has genotype-specific effects on liver insulin function. At 12 weeks, no difference in liver insulin signaling was detected between fasting ApoE3 and ApoE4 mice. At 72 weeks however, ApoE4 mice had lower IRS-1 and PI3K expression, and reduced Akt phosphorylation. This decline was associated with lower insulin and higher glucose in ApoE4 mouse liver. Liver cholesterol was not affected. These results show that ApoE4 expression reduces liver insulin signaling and insulin levels, leading to higher glucose content.
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Affiliation(s)
- Qi-Rui Ong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Elizabeth S Chan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mei-Li Lim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Boon-Seng Wong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Reduced phosphorylation of brain insulin receptor substrate and Akt proteins in apolipoprotein-E4 targeted replacement mice. Sci Rep 2014; 4:3754. [PMID: 24435134 PMCID: PMC3894554 DOI: 10.1038/srep03754] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 12/24/2013] [Indexed: 01/03/2023] Open
Abstract
Human ApoE4 accelerates memory decline in ageing and in Alzheimer's disease. Although intranasal insulin can improve cognition, this has little effect in ApoE4 subjects. To understand this ApoE genotype-dependent effect, we examined brain insulin signaling in huApoE3 and huApoE4 targeted replacement (TR) mice. At 32 weeks, lower insulin receptor substrate 1 (IRS1) at S636/639 and Akt phosphorylation at T308 were detected in fasting huApoE4 TR mice as compared to fasting huApoE3 TR mice. These changes in fasting huApoE4 TR mice were linked to lower brain glucose content and have no effect on plasma glucose level. However, at 72 weeks of age, these early changes were accompanied by reduction in IRS2 expression, IRS1 phosphorylation at Y608, Akt phosphorylation at S473, and MAPK (p38 and p44/42) activation in the fasting huApoE4 TR mice. The lower brain glucose was significantly associated with higher brain insulin in the aged huApoE4 TR mice. These results show that ApoE4 reduces brain insulin signaling and glucose level leading to higher insulin content.
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de la Monte SM. Intranasal insulin therapy for cognitive impairment and neurodegeneration: current state of the art. Expert Opin Drug Deliv 2013; 10:1699-709. [PMID: 24215447 PMCID: PMC4551402 DOI: 10.1517/17425247.2013.856877] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
INTRODUCTION Growing evidence supports the concept that insulin resistance plays an important role in the pathogenesis of cognitive impairment and neurodegeneration, including in Alzheimer's disease (AD). The metabolic hypothesis has led to the development and utilization of insulin- and insulin agonist-based treatments. Therapeutic challenges faced include the ability to provide effective treatments that do not require repeated injections and also the ability to minimize the potentially hazardous off-target effects. AREAS COVERED This review covers the role of intranasal insulin therapy for cognitive impairment and neurodegeneration, particularly AD. The literature reviewed focuses on data published within the past 5 years as this field is evolving rapidly. The review provides evidence that brain insulin resistance is an important and early abnormality in AD, and that increasing brain supply and utilization of insulin improves cognition and memory. Emphasis was placed on discussing outcomes of clinical trials and interpreting discordant results to clarify the benefits and limitations of intranasal insulin therapy. EXPERT OPINION Intranasal insulin therapy can efficiently and directly target the brain to support energy metabolism, myelin maintenance, cell survival and neuronal plasticity, which begin to fail in the early stages of neurodegeneration. Efforts must continue toward increasing the safety, efficacy and specificity of intranasal insulin therapy.
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Affiliation(s)
- Suzanne M de la Monte
- Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Departments of Pathology (Neuropathology), Neurology, and Neurosurgery , Pierre Galletti Research Building, Claverick Street, Room 419, Providence, RI 02903 , USA +1 401 444 7364 ; +1 401 444 2939 ;
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Heni M, Kullmann S, Ketterer C, Guthoff M, Bayer M, Staiger H, Machicao F, Häring HU, Preissl H, Veit R, Fritsche A. Differential effect of glucose ingestion on the neural processing of food stimuli in lean and overweight adults. Hum Brain Mapp 2013; 35:918-28. [PMID: 23307469 DOI: 10.1002/hbm.22223] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 10/16/2012] [Accepted: 10/22/2012] [Indexed: 12/19/2022] Open
Abstract
Eating behavior is crucial in the development of obesity and Type 2 diabetes. To further investigate its regulation, we studied the effects of glucose versus water ingestion on the neural processing of visual high and low caloric food cues in 12 lean and 12 overweight subjects by functional magnetic resonance imaging. We found body weight to substantially impact the brain's response to visual food cues after glucose versus water ingestion. Specifically, there was a significant interaction between body weight, condition (water versus glucose), and caloric content of food cues. Although overweight subjects showed a generalized reduced response to food objects in the fusiform gyrus and precuneus, the lean group showed a differential pattern to high versus low caloric foods depending on glucose versus water ingestion. Furthermore, we observed plasma insulin and glucose associated effects. The hypothalamic response to high caloric food cues negatively correlated with changes in blood glucose 30 min after glucose ingestion, while especially brain regions in the prefrontal cortex showed a significant negative relationship with increases in plasma insulin 120 min after glucose ingestion. We conclude that the postprandial neural processing of food cues is highly influenced by body weight especially in visual areas, potentially altering visual attention to food. Furthermore, our results underline that insulin markedly influences prefrontal activity to high caloric food cues after a meal, indicating that postprandial hormones may be potential players in modulating executive control.
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Affiliation(s)
- Martin Heni
- Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Department of Internal Medicine, Eberhard Karls University Tübingen, Germany
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Mazzatenta A, Pokorski M, Di Giulio C. Real-Time Breath Analysis in Type 2 Diabetes Patients During Cognitive Effort. NEUROBIOLOGY OF RESPIRATION 2013; 788:247-53. [DOI: 10.1007/978-94-007-6627-3_35] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Clark I, Atwood C, Bowen R, Paz-Filho G, Vissel B. Tumor necrosis factor-induced cerebral insulin resistance in Alzheimer's disease links numerous treatment rationales. Pharmacol Rev 2012; 64:1004-26. [PMID: 22966039 DOI: 10.1124/pr.112.005850] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The evident limitations of the amyloid theory of the pathogenesis of Alzheimer's disease are increasingly putting alternatives in the spotlight. We argue here that a number of independently developing approaches to therapy-including specific and nonspecific anti-tumor necrosis factor (TNF) agents, apolipoprotein E mimetics, leptin, intranasal insulin, the glucagon-like peptide-1 mimetics and glycogen synthase kinase-3 (GSK-3) antagonists-are all part of an interlocking chain of events. All these approaches inform us that inflammation and thence cerebral insulin resistance constitute the pathway on which to focus for a successful clinical outcome in treating this disease. The key link in this chain presently absent is a recognition by Alzheimer's research community of the long-neglected history of TNF induction of insulin resistance. When this is incorporated into the bigger picture, it becomes evident that the interventions we discuss are not competing alternatives but equally valid approaches to correcting different parts of the same pathway to Alzheimer's disease. These treatments can be expected to be at least additive, and conceivably synergistic, in effect. Thus the inflammation, insulin resistance, GSK-3, and mitochondrial dysfunction hypotheses are not opposing ideas but stages of the same fundamental, overarching, pathway of Alzheimer's disease pathogenesis. The insight this provides into progenitor cells, including those involved in adult neurogenesis, is a key part of this approach. This pathway also has therapeutic implications for other circumstances in which brain TNF is pathologically increased, such as stroke, traumatic brain injury, and the infectious disease encephalopathies.
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Affiliation(s)
- Ian Clark
- Division of Medical Science and Biochemistry, Research School of Biology, Australian National University, Canberra ACT, Australia.
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Seed Ahmed M, Kovoor A, Nordman S, Abu Seman N, Gu T, Efendic S, Brismar K, Östenson CG, Gu HF. Increased expression of adenylyl cyclase 3 in pancreatic islets and central nervous system of diabetic Goto-Kakizaki rats: a possible regulatory role in glucose homeostasis. Islets 2012; 4:343-8. [PMID: 23018249 PMCID: PMC3524141 DOI: 10.4161/isl.22283] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Adenylyl cyclase 3 (AC3) is expressed in pancreatic islets of the Goto-Kakizaki (GK) rat, a spontaneous animal model of type 2 diabetes (T2D), and also exerts genetic effects on the regulation of body weight in man. In addition to pancreatic islets, the central nervous system (CNS) plays an important role in the pathogenesis of T2D and obesity by regulating feeding behavior, body weight and glucose metabolism. In the present study, we have investigated AC3 expression in pancreatic islets, striatum and hypothalamus of GK rats to evaluate its role in the regulation of glucose homeostasis. GK and Wistar rats at the age of 2.5 mo were used. A group of GK rats were implanted with sustained insulin release chips for 15 d. Plasma glucose and serum insulin levels were measured. AC3 gene expression levels in pancreatic islets, striatum and hypothalamus were determined by using real-time RT-PCR. Results indicated that plasma glucose levels in Wistar rats were found to be similar to insulin-treated GK rats, and significantly lower compared with non-treated GK rats. AC3 expression levels in pancreatic islets, striatum and hypothalamus of GK rats were higher compared with Wistar rats, while the levels were intermediate in insulin-treated GK rats. The AC3 expression display patterns between pancreatic islets and striatum-hypothalamus were similar. The present study thus provides the first evidence that AC3 is overexpressed in the regions of striatum and hypothalamus of brain, and similarly in pancreatic islets of GK rats suggesting that AC3 plays a role in regulation of glucose homeostasis via CNS and insulin secretion.
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Affiliation(s)
- Mohammed Seed Ahmed
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Karolinska University Hospital; Stockholm, Sweden
| | - Abraham Kovoor
- Department of Biomedical and Pharmaceutical Sciences; University of Rhode Island; Kingston, RI USA
| | - Sofia Nordman
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Karolinska University Hospital; Stockholm, Sweden
| | - Norhashimah Abu Seman
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Karolinska University Hospital; Stockholm, Sweden
| | - Tianwei Gu
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Karolinska University Hospital; Stockholm, Sweden
| | - Suad Efendic
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Karolinska University Hospital; Stockholm, Sweden
| | - Kerstin Brismar
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Karolinska University Hospital; Stockholm, Sweden
| | - Claes-Göran Östenson
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Karolinska University Hospital; Stockholm, Sweden
| | - Harvest F. Gu
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Karolinska University Hospital; Stockholm, Sweden
- Correspondence to: Harvest F. Gu,
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Adam CL, Findlay PA, Aitken RP, Milne JS, Wallace JM. In vivo changes in central and peripheral insulin sensitivity in a large animal model of obesity. Endocrinology 2012; 153:3147-57. [PMID: 22593271 DOI: 10.1210/en.2012-1134] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Obesity disrupts homeostatic energy balance circuits leading to insulin resistance. Here we examined in vivo peripheral and central insulin sensitivity, and whether central insensitivity in terms of the voluntary food intake (VFI) response occurs within the hypothalamus or at blood-brain transfer level, during obesity and after subsequent weight loss. Sheep with intracerebroventricular (i.c.v.) cannulae were fed complete diet for 40 wk ad libitum (obese group) or at control level (controls). Thereafter, obese sheep were food restricted (slimmers) and controls fed ad libitum (fatteners) for 16 wk. Dual-energy x-ray absorptiometry (DEXA) measured total body fat, insulin analyses in blood and cerebrospinal fluid (CSF) assessed blood-brain transfer, i.v. glucose tolerance test (GTT) and insulin tolerance test (ITT) measured peripheral insulin sensitivity, and VFI responses to icv insulin assessed intrahypothalamic sensitivity. Insulinemia was higher in obese than controls; plasma insulin correlated with DEXA body fat and CSF insulin. Insulinemia was higher in fatteners than slimmers but ratio of CSF to plasma insulin correlated only in fatteners. Plasma glucose baseline and area under the curve were higher during GTT and ITT in obese than controls and during ITT in fatteners than slimmers. GTT and ITT glucose area under the curve correlated with DEXA body fat. VFI decreased after i.c.v. insulin, with response magnitude correlating negatively with DEXA body fat. Overall, insulin resistance developed first in the periphery and then within the brain, thereafter correlating with adiposity; central resistance in terms of VFI response resulted from intrahypothalamic insensitivity rather than impaired blood-brain transfer; modest weight loss improved peripheral but not central insulin sensitivity and induced central hypoinsulinemia.
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Affiliation(s)
- Clare L Adam
- Obesity and Metabolic Health Theme, Rowett Institute of Nutrition and Health, University of Aberdeen, Bucksburn, Aberdeen AB21 9SB, United Kingdom.
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Heni M, Kullmann S, Ketterer C, Guthoff M, Linder K, Wagner R, Stingl KT, Veit R, Staiger H, Häring HU, Preissl H, Fritsche A. Nasal insulin changes peripheral insulin sensitivity simultaneously with altered activity in homeostatic and reward-related human brain regions. Diabetologia 2012; 55:1773-82. [PMID: 22434537 DOI: 10.1007/s00125-012-2528-y] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 02/15/2012] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS Impaired insulin sensitivity is a major factor leading to type 2 diabetes. Animal studies suggest that the brain is involved in the regulation of insulin sensitivity. We investigated whether insulin action in the human brain regulates peripheral insulin sensitivity and examined which brain areas are involved. METHODS Insulin and placebo were given intranasally. Plasma glucose, insulin and C-peptide were measured in 103 participants at 0, 30 and 60 min. A subgroup (n = 12) was also studied with functional MRI, and blood sampling at 0, 30 and 120 min. For each time-point, the HOMA of insulin resistance (HOMA-IR) was calculated as an inverse estimate of peripheral insulin sensitivity. RESULTS Plasma insulin increased and subsequently decreased. This excursion was accompanied by slightly decreased plasma glucose, resulting in an initially increased HOMA-IR. At 1 h after insulin spray, the HOMA-IR subsequently decreased and remained lower up to 120 min. An increase in hypothalamic activity was observed, which correlated with the increased HOMA-IR at 30 min post-spray. Activity in the putamen, right insula and orbitofrontal cortex correlated with the decreased HOMA-IR at 120 min post-spray. CONCLUSIONS/INTERPRETATION Central insulin action in specific brain areas, including the hypothalamus, may time-dependently regulate peripheral insulin sensitivity. This introduces a potential novel mechanism for the regulation of peripheral insulin sensitivity and underlines the importance of cerebral insulin action for the whole organism.
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Affiliation(s)
- M Heni
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Otfried-Müller-Str 10, 72076 Tübingen, Germany
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Schiöth HB, Craft S, Brooks SJ, Frey WH, Benedict C. Brain insulin signaling and Alzheimer's disease: current evidence and future directions. Mol Neurobiol 2011; 46:4-10. [PMID: 22205300 PMCID: PMC3443484 DOI: 10.1007/s12035-011-8229-6] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 12/16/2011] [Indexed: 01/19/2023]
Abstract
Insulin receptors in the brain are found in high densities in the hippocampus, a region that is fundamentally involved in the acquisition, consolidation, and recollection of new information. Using the intranasal method, which effectively bypasses the blood–brain barrier to deliver and target insulin directly from the nose to the brain, a series of experiments involving healthy humans has shown that increased central nervous system (CNS) insulin action enhances learning and memory processes associated with the hippocampus. Since Alzheimer's disease (AD) is linked to CNS insulin resistance, decreased expression of insulin and insulin receptor genes and attenuated permeation of blood-borne insulin across the blood–brain barrier, impaired brain insulin signaling could partially account for the cognitive deficits associated with this disease. Considering that insulin mitigates hippocampal synapse vulnerability to amyloid beta and inhibits the phosphorylation of tau, pharmacological strategies bolstering brain insulin signaling, such as intranasal insulin, could have significant therapeutic potential to deter AD pathogenesis.
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Affiliation(s)
- Helgi B Schiöth
- Department of Neuroscience, Uppsala University, Box 593, Husargatan 3, Uppsala, Sweden
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