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Yigit AA, Kilinc S, Olcuoglu R, Arnous EA. The effects of orlistat on oxidative stress, recognition memory, spatial memory and hippocampal tissue in experimentally induced obesity in rats. Behav Brain Res 2024; 462:114894. [PMID: 38311071 DOI: 10.1016/j.bbr.2024.114894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/06/2024]
Abstract
This study investigates the impact of orlistat on oxidative stress, spatial memory, recognition memory, and hippocampal tissue in obese rats. The study groups were divided into control, high fat diet-induced obese (HFDIO), HFDIO+orlistat (HFDIO+ORL) groups, each consisting of 8 animals. While control fed with standart diet, HFDIO and HFDIO+ORL fed with high-fat diets for 8 weeks to induce obesity. Then, ORL treated 10 mg/kg for 7 weeks, while control and HFDIO get water. At 16th week, novel object recognition (NOR) and Morris water maze (MWM) tests were performed. TNF-alpha, IL-1beta levels in hippocampal tissue, and total/native thiol/disulphide levels in serum were measured. TNF-alpha level of HFDIO was higher than control, while lower in HFDIO+ORL compared to HFDIO as like IL-1beta level. On the contrary, serum total thiol level was lower in HFDIO than control and higher in HFDIO+ORL compared to the HFDIO, while disulphide level was opposite of the total thiol levels. While recognition index was higher in HFDIO+ORL, in MWM, latency of finding platform in HFDIO was higher than control and latency of HFDIO+ORL was very similar to control in 2-4 days. The HFDIO group demonstrated decrease in time spent in platform zone compared to control, whereas time spent of the HFDIO+ORL was higher than HFDIO. Our study demonstrates that orlistat administration exerts beneficial effects on oxidative stress, spatial memory, recognition memory, and hippocampal tissue in obese rats. It shows that orlistat may have potential therapeutic implications for obesity-related cognitive impairments and hippocampal dysfunction.
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Affiliation(s)
- Ayse Arzu Yigit
- Department of Physiology, Faculty of Medicine, Baskent University, Ankara 06790, Türkiye.
| | - Sevtap Kilinc
- Department of Physiology, Faculty of Medicine, Baskent University, Ankara 06790, Türkiye
| | - Rukiye Olcuoglu
- Department of Physiology, Faculty of Medicine, Baskent University, Ankara 06790, Türkiye
| | - Elif Azra Arnous
- Department of Physiology, Faculty of Medicine, Baskent University, Ankara 06790, Türkiye
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2
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Hamilton J, Nguyen C, McAvoy M, Roeder N, Richardson B, Quattrin T, Hajnal A, Thanos PK. Calorie restriction, but not Roux-en-Y gastric bypass surgery, increases [ 3 H] PK11195 binding in a rat model of obesity. Synapse 2023; 77:e22258. [PMID: 36352528 DOI: 10.1002/syn.22258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 10/05/2022] [Accepted: 10/09/2022] [Indexed: 11/11/2022]
Abstract
Roux-en-Y gastric bypass surgery (RYGB) remains an effective weight-loss method used to treat obesity. While it is successful in combating obesity, there are many lingering questions related to the changes in the brain following RYGB surgery, one of them being its effects on neuroinflammation. While it is known that chronic high-fat diet (HFD) contributes to obesity and neuroinflammation, it remains to be understood whether bariatric surgery can ameliorate diet-induced inflammatory responses. To examine this, rats were assigned to either a normal diet (ND) or a HFD for 8 weeks. Rats fed a HFD were split into the following groups: sham surgery with ad libitum access to HFD (sham-HF); sham surgery with calorie-restricted HFD (sham-FR); RYGB surgery with ad libitum access to HFD (RYGB). Following sham or RYGB surgeries, rats were maintained on their diets for 9 weeks before being euthanized. [3 H] PK11195 autoradiography was then performed on fresh-frozen brain tissue in order to measure activated microglia. Sham-FR rats showed increased [3 H] PK11195 binding in the amygdala (63%), perirhinal (60%), and ectorhinal cortex (53%) compared with the ND rats. Obese rats who had the RYGB surgery did not show this increased inflammatory effect. Since the sham-FR and RYGB rats were fed the same amount of HFD, the surgery itself seems responsible for this attenuation in [3 H] PK11195 binding. We speculate that calorie restriction following obese conditions may be seen as a stressor and contribute to inflammation in the brain. Further research is needed to verify this mechanism.
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Affiliation(s)
- John Hamilton
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Cynthia Nguyen
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Margaret McAvoy
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Nicole Roeder
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.,Department of Psychology, University at Buffalo, Buffalo, New York, USA
| | - Brittany Richardson
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.,Department of Psychology, University at Buffalo, Buffalo, New York, USA
| | - Teresa Quattrin
- Department of Pediatrics, University at Buffalo, UBMD Pediatrics, JR Oishei Children's Hospital, Buffalo, New York, USA
| | - Andras Hajnal
- Department of Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Panayotis K Thanos
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.,Department of Psychology, University at Buffalo, Buffalo, New York, USA
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3
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Parent MB, Higgs S, Cheke LG, Kanoski SE. Memory and eating: A bidirectional relationship implicated in obesity. Neurosci Biobehav Rev 2022; 132:110-129. [PMID: 34813827 PMCID: PMC8816841 DOI: 10.1016/j.neubiorev.2021.10.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/17/2021] [Accepted: 10/28/2021] [Indexed: 01/03/2023]
Abstract
This paper reviews evidence demonstrating a bidirectional relationship between memory and eating in humans and rodents. In humans, amnesia is associated with impaired processing of hunger and satiety cues, disrupted memory of recent meals, and overconsumption. In healthy participants, meal-related memory limits subsequent ingestive behavior and obesity is associated with impaired memory and disturbances in the hippocampus. Evidence from rodents suggests that dorsal hippocampal neural activity contributes to the ability of meal-related memory to control future intake, that endocrine and neuropeptide systems act in the ventral hippocampus to provide cues regarding energy status and regulate learned aspects of eating, and that consumption of hypercaloric diets and obesity disrupt these processes. Collectively, this evidence indicates that diet-induced obesity may be caused and/or maintained, at least in part, by a vicious cycle wherein excess intake disrupts hippocampal functioning, which further increases intake. This perspective may advance our understanding of how the brain controls eating, the neural mechanisms that contribute to eating-related disorders, and identify how to treat diet-induced obesity.
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Affiliation(s)
- Marise B. Parent
- Neuroscience Institute & Department of Psychology, Georgia State University, Box 5030, Atlanta, GA 30303-5030, United States,Corresponding author: Marise B. Parent, , Georgia State University, PO Box 5030, Atlanta, GA 30303-5030, USA. Fax: 404-413-5446
| | - Suzanne Higgs
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, BI5 2TT, United Kingdom
| | - Lucy G. Cheke
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB United Kingdom
| | - Scott E Kanoski
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, 90089-0371, United States
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4
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An Z, Wang H, Mokadem M. Role of the Autonomic Nervous System in Mechanism of Energy and Glucose Regulation Post Bariatric Surgery. Front Neurosci 2021; 15:770690. [PMID: 34887725 PMCID: PMC8649921 DOI: 10.3389/fnins.2021.770690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 10/15/2021] [Indexed: 01/06/2023] Open
Abstract
Even though lifestyle changes are the mainstay approach to address obesity, Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are the most effective and durable treatments facing this pandemic and its associated metabolic conditions. The traditional classifications of bariatric surgeries labeled them as “restrictive,” “malabsorptive,” or “mixed” types of procedures depending on the anatomical rearrangement of each one of them. This conventional categorization of bariatric surgeries assumed that the “restrictive” procedures induce their weight loss and metabolic effects by reducing gastric content and therefore having a smaller reservoir. Similarly, the “malabsorptive” procedures were thought to induce their main energy homeostatic effects from fecal calorie loss due to intestinal malabsorption. Observational data from human subjects and several studies from rodent models of bariatric surgery showed that neither of those concepts is completely true, at least in explaining the multiple metabolic changes and the alteration in energy balance that those two surgeries induce. Rather, neuro-hormonal mechanisms have been postulated to underly the physiologic effects of those two most performed bariatric procedures. In this review, we go over the role the autonomic nervous system plays- through its parasympathetic and sympathetic branches- in regulating weight balance and glucose homeostasis after SG and RYGB.
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Affiliation(s)
- Zhibo An
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Haiying Wang
- Department of Physiology, Basic Medical School of Jining Medical University, Jining, China
| | - Mohamad Mokadem
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, IA, United States.,Fraternal Order of Eagles Diabetes Research Center, The University of Iowa, Iowa City, IA, United States.,Obesity Research and Education Initiative, The University of Iowa, Iowa City, IA, United States.,Iowa City Veterans Affairs Health Care System, Iowa City, IA, United States
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5
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Stranahan AM. Visceral adiposity, inflammation, and hippocampal function in obesity. Neuropharmacology 2021; 205:108920. [PMID: 34902347 DOI: 10.1016/j.neuropharm.2021.108920] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 11/09/2021] [Accepted: 12/08/2021] [Indexed: 02/06/2023]
Abstract
The 'apple-shaped' anatomical pattern that accompanies visceral adiposity increases risk for multiple chronic diseases, including conditions that impact the brain, such as diabetes and hypertension. However, distinguishing between the consequences of visceral obesity, as opposed to visceral adiposity-associated metabolic and cardiovascular pathologies, presents certain challenges. This review summarizes current literature on relationships between adipose tissue distribution and cognition in preclinical models and highlights unanswered questions surrounding the potential role of tissue- and cell type-specific insulin resistance in these effects. While gaps in knowledge persist related to insulin insensitivity and cognitive impairment in obesity, several recent studies suggest that cells of the neurovascular unit contribute to hippocampal synaptic dysfunction, and this review interprets those findings in the context of progressive metabolic dysfunction in the CNS. Signalling between cerebrovascular endothelial cells, astrocytes, microglia, and neurons has been linked with memory deficits in visceral obesity, and this article describes the cellular changes in each of these populations with respect to their role in amplification or diminution of peripheral signals. The picture emerging from these studies, while incomplete, implicates pro-inflammatory cytokines, insulin resistance, and hyperglycemia in various stages of obesity-induced hippocampal dysfunction. As in the parable of the five blind wanderers holding different parts of an elephant, considerable work remains in order to assemble a model for the underlying mechanisms linking visceral adiposity with age-related cognitive decline.
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Affiliation(s)
- Alexis M Stranahan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, 1462 Laney Walker Blvd, Augusta, GA, 30912, USA.
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6
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Masetto Antunes M, Godoy G, Masi LN, Curi R, Barbosa Bazotte R. Prefrontal Cortex and Hippocampus Inflammation in Mice Fed High-Carbohydrate or High-Fat Diets. J Med Food 2021; 25:110-113. [PMID: 34495750 DOI: 10.1089/jmf.2021.0026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We previously reported that a high-carbohydrate diet (HCD) induced systemic inflammation and higher gene expression of proinflammatory mediators in the liver, skeletal muscle, and brain than a high-fat diet (HFD). However, the differences between the groups were less pronounced in the brain. In this study, we extended the evaluation of inflammation to specific areas of the brain. In this study, we evaluated the gene expression of caspase 2, caspase 3, caspase 9, cyclooxygenase-2 (Cox 2), inducible nitric oxide synthase (iNOS), interleukin (IL), IL-6, IL-1β, IL-10, IL-4, tumor necrosis factor-alpha (TNF-α), integrin subunit alpha m (Itgam), S100 protein (S100), allograft inflammatory factor 1 (Aif1), and glial fibrillary acidic protein (Gfap) in the prefrontal cortex and hippocampus of male Swiss mice that were fed with HCD or HFD for 8 weeks. The HCD group exhibited higher IL-1β expression, whereas the HFD group showed higher TNF-α expression in the prefrontal cortex. In the hippocampus, TNF-α expression was higher in the HFD group. IL-1β and TNF-α are proinflammatory cytokines that have been associated with impaired brain function and numerous brain disorders. Our results indicate that both HCD and HFD promote prefrontal cortex inflammation; however, the hippocampus seems more sensitive to a HFD than HCD.
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Affiliation(s)
- Marina Masetto Antunes
- Post-Graduation Program in Pharmaceutical Sciences, State University of Maringá, Maringá, Brazil
| | - Guilherme Godoy
- Post-Graduation Program in Pharmaceutical Sciences, State University of Maringá, Maringá, Brazil
| | - Laureane Nunes Masi
- Interdisciplinary Post-Graduate Program in Health Sciences, Cruzeiro do Sul University, São Paulo, Brazil and Immunobiological Production Section, Bioindustrial Center, Butantan Institute, São Paulo, Brazil
| | - Rui Curi
- Interdisciplinary Post-Graduate Program in Health Sciences, Cruzeiro do Sul University, São Paulo, Brazil and Immunobiological Production Section, Bioindustrial Center, Butantan Institute, São Paulo, Brazil
| | - Roberto Barbosa Bazotte
- Post-Graduation Program in Pharmaceutical Sciences, State University of Maringá, Maringá, Brazil.,Department of Pharmacology and Therapeutics, State University of Maringá, Maringá, Brazil
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7
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Short-term high-fat diet induces cognitive decline, aggression, and anxiety-like behavior in adult zebrafish. Prog Neuropsychopharmacol Biol Psychiatry 2021; 110:110288. [PMID: 33626334 DOI: 10.1016/j.pnpbp.2021.110288] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/04/2021] [Accepted: 02/16/2021] [Indexed: 12/22/2022]
Abstract
Obesity is a global health problem with high prevalence and defined by a high body mass index (BMI). Several comorbidities affecting the central nervous system (CNS) are associated with obesity (e.g., neurodegenerative diseases, cognitive deficit, and psychobehavioral disturbs). The zebrafish (Danio rerio) has been considered a suitable model organism to investigate the neurobehavioral features of various human diseases. Here, we verify the impact of a high-fat diet (HFD) on the CNS by specifically assessing the effects of short-term HFD on anxiety-like responses, aggression, social preference, and memory, which are essential behaviors for survival and reproduction. Animals were separated in three experimental groups. The standard diet group (SD) received 7.5 mg/fish of dry food, while HFD groups received 5 mg/fish dry food plus 7.5 (HFD-7.5) or 15 mg/fish (HFD-15) of chicken egg yolk daily. Dietary fat content (w/w) was approximately 6.5%, 16.9%, and 21.1%, respectively. We performed behavioral tests and morphometric analyses after two weeks of HFD. In comparison to SD animals, HFD groups showed typical obesogenic responses with increases in BMI, abdominal length, and body weight. HFD individuals also showed increased aggression and anxiety-like behaviors in the mirror-induced aggression and novel tank diving tests, respectively. Interestingly, HFD did not change the social preference behavior, mean swimming speed or spontaneous activity levels, while the HFD-15 group showed cognitive deficits in the inhibitory avoidance test. Collectively, this "proof-of-concept" study is the first report to characterize the effects of short-term HFD on different behavioral domains of zebrafish with high degree of face validity. Moreover, our data reinforce the growing utility of zebrafish to explore the neurobehavioral basis of obesity, providing clinically translatable data, complementing the existing rodent models and supporting future mechanistic studies.
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8
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Bond DJ, Silveira LE, Torres IJ, Lam RW, Yatham LN. Weight gain as a risk factor for progressive neurochemical abnormalities in first episode mania patients: a longitudinal magnetic resonance spectroscopy study. Psychol Med 2021; 52:1-9. [PMID: 33706825 DOI: 10.1017/s0033291721000544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND We previously reported that bipolar disorder (BD) patients with clinically significant weight gain (CSWG; ⩾7% of baseline weight) in the 12 months after their first manic episode experienced greater limbic brain volume loss than patients without CSWG. It is unknown whether CSWG is also a risk factor for progressive neurochemical abnormalities. METHODS We investigated whether 12-month CSWG predicted greater 12-month decreases in hippocampal N-acetylaspartate (NAA) and greater increases in glutamate + glutamine (Glx) following a first manic episode. In BD patients (n = 58) and healthy comparator subjects (HS; n = 34), we measured baseline and 12-month hippocampal NAA and Glx using bilateral 3-Tesla single-voxel proton magnetic resonance spectroscopy. We used general linear models for repeated measures to investigate whether CSWG predicted neurochemical changes. RESULTS Thirty-three percent of patients and 18% of HS experienced CSWG. After correcting for multiple comparisons, CSWG in patients predicted a greater decrease in left hippocampal NAA (effect size = -0.52, p = 0.005). CSWG also predicted a greater decrease in left hippocampal NAA in HS with a similar effect size (-0.53). A model including patients and HS found an effect of CSWG on Δleft NAA (p = 0.007), but no diagnosis effect and no diagnosis × CSWG interaction, confirming that CSWG had similar effects in patients and HS. CONCLUSION CSWG is a risk factor for decreasing hippocampal NAA in BD patients and HS. These results suggest that the well-known finding of reduced NAA in BD may result from higher body mass index in patients rather than BD diagnosis.
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Affiliation(s)
- David J Bond
- Department of Psychiatry and Behavioral Sciences, University of Minnesota Medical School, Minneapolis, MN, USA
- Mood Disorders Centre, University of British Columbia, Vancouver, BC, Canada
| | - Leonardo E Silveira
- Laboratory of Molecular Psychiatry, Centro de Pesquisas Experimentais, Hospital de Clínicas de Porto Alegre, and INCT for Translational Medicine, Porto Alegre, RS, Brazil
| | - Ivan J Torres
- Mood Disorders Centre, University of British Columbia, Vancouver, BC, Canada
| | - Raymond W Lam
- Mood Disorders Centre, University of British Columbia, Vancouver, BC, Canada
| | - Lakshmi N Yatham
- Mood Disorders Centre, University of British Columbia, Vancouver, BC, Canada
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Dias GP, Murphy T, Stangl D, Ahmet S, Morisse B, Nix A, Aimone LJ, Aimone JB, Kuro-O M, Gage FH, Thuret S. Intermittent fasting enhances long-term memory consolidation, adult hippocampal neurogenesis, and expression of longevity gene Klotho. Mol Psychiatry 2021; 26:6365-6379. [PMID: 34031536 PMCID: PMC8760057 DOI: 10.1038/s41380-021-01102-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 03/19/2021] [Accepted: 04/06/2021] [Indexed: 02/03/2023]
Abstract
Daily calorie restriction (CR) and intermittent fasting (IF) enhance longevity and cognition but the effects and mechanisms that differentiate these two paradigms are unknown. We examined whether IF in the form of every-other-day feeding enhances cognition and adult hippocampal neurogenesis (AHN) when compared to a matched 10% daily CR intake and ad libitum conditions. After 3 months under IF, female C57BL6 mice exhibited improved long-term memory retention. IF increased the number of BrdU-labeled cells and neuroblasts in the hippocampus, and microarray analysis revealed that the longevity gene Klotho (Kl) was upregulated in the hippocampus by IF only. Furthermore, we found that downregulating Kl in human hippocampal progenitor cells led to decreased neurogenesis, whereas Kl overexpression increased neurogenesis. Finally, histological analysis of Kl knockout mice brains revealed that Kl is required for AHN, particularly in the dorsal hippocampus. These data suggest that IF is superior to 10% CR in enhancing memory and identifies Kl as a novel candidate molecule that regulates the effects of IF on cognition likely via AHN enhancement.
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Affiliation(s)
- Gisele Pereira Dias
- grid.13097.3c0000 0001 2322 6764Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Tytus Murphy
- grid.13097.3c0000 0001 2322 6764Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Doris Stangl
- grid.13097.3c0000 0001 2322 6764Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Selda Ahmet
- grid.13097.3c0000 0001 2322 6764Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Benjamin Morisse
- grid.13097.3c0000 0001 2322 6764Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Alina Nix
- grid.13097.3c0000 0001 2322 6764Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Lindsey J. Aimone
- grid.250671.70000 0001 0662 7144Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA USA
| | - James B. Aimone
- grid.474520.00000000121519272Center for Computing Research, Sandia National Laboratories, Albuquerque, NM USA
| | - Makoto Kuro-O
- grid.410804.90000000123090000Division of Anti-Ageing Medicine, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan
| | - Fred H. Gage
- grid.250671.70000 0001 0662 7144Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA USA
| | - Sandrine Thuret
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK. .,Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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Qin X, Wang W, Wu H, Liu D, Wang R, Xu J, Jiang H, Pan F. PPARγ-mediated microglial activation phenotype is involved in depressive-like behaviors and neuroinflammation in stressed C57BL/6J and ob/ob mice. Psychoneuroendocrinology 2020; 117:104674. [PMID: 32422516 DOI: 10.1016/j.psyneuen.2020.104674] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/06/2020] [Accepted: 03/25/2020] [Indexed: 01/17/2023]
Abstract
BACKGROUND There is an increased risk for obese patients with chronic low-grade inflammation to develop depression. Stress induces microglial activation and neuroinflammation that play crucial roles in the pathogenesis of depression. Peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear transcription factor, regulates microglial polarization and neuroinflammation. Our study aimed to investigate the role of PPARγ in the development of depressive symptoms and neuroinflammation induced by chronic unpredictable mild stress (CUMS) in wild-type/C57BL/6J (wt) and leptin-deficient (ob/ob) mice. METHODS CUMS was used to build a depression model with wt and ob/ob mice. Depressive-like behaviors were evaluated by sucrose preference test, open field test, tail suspension test, and Morris water maze test. Cytokines, the activated microglial state, and nuclear factor-κB (NF-κB) and PPARγ expression in the prefrontal cortex (PFC) and hippocampus (HIP) were examined by enzyme-linked immunosorbent assay (ELISA), immunofluorescence, and western blotting. Additionally, pioglitazone, an agonist of PPARγ, was used as a treatment intervention. RESULTS After CUMS, ob/ob mice exhibited severe behavioral disorders and spatial memory impairment, and higher levels of pro-inflammatory cytokines, M1/M2 ratios, and NF-κB activation, as well as lower levels of anti-inflammatory cytokines and PPARγ expression in the PFC and HIP compared to wt mice. Administration of pioglitazone relieved these alterations in wt and ob/ob mice. CONCLUSIONS CUMS was able to induce severe depressive-like behaviors, neuroinflammation, and reduced expression of PPARγ in ob/ob mice as compared to wt mice. This suggests that PPARγ mediates the microglial activation phenotype, which might be related to the susceptibility of stressed ob/ob mice to develop depressive disorder.
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Affiliation(s)
- Xiaqing Qin
- Department of Medical Psychology and Ethics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Wei Wang
- Department of Medical Psychology and Ethics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Huiran Wu
- Department of Medical Psychology and Ethics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Dexiang Liu
- Department of Medical Psychology and Ethics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Rui Wang
- Department of Medical Psychology and Ethics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Jingjing Xu
- Department of Medical Psychology and Ethics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Hong Jiang
- Department of Medical Psychology and Ethics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Fang Pan
- Department of Medical Psychology and Ethics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.
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11
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Dias IR, Santos CDS, Magalhães CODE, de Oliveira LRS, Peixoto MFD, De Sousa RAL, Cassilhas RC. Does calorie restriction improve cognition? IBRO Rep 2020; 9:37-45. [PMID: 33336102 PMCID: PMC7733132 DOI: 10.1016/j.ibror.2020.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/29/2020] [Indexed: 01/14/2023] Open
Abstract
Calorie restriction (CR) has been considered the most effective non-pharmacological intervention to counteract aging-related diseases and improve longevity. This intervention has shown beneficial effects in the prevention and treatment of several chronic diseases and functional declines related to aging, such as Parkinson's, Alzheimer's, and neuroendocrine disorders. However, the effects of CR on cognition show controversial results since its effects vary according to intensity, duration, and the period of CR. This review focuses on the main studies published in the last ten years regarding the consequences of CR on cognition in different neurological diseases and conditions of experimental animals. Also, possible CR mimetics are discussed. These findings highlight the potential beneficial effects of CR of up to 40 % on cognition when started early in life in non human animals.
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Affiliation(s)
- Isabella Rocha Dias
- Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Carina de Sousa Santos
- Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Caíque Olegário Diniz E Magalhães
- Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Lucas Renan Sena de Oliveira
- Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Marco Fabrício Dias Peixoto
- Department of Physical Education, Federal University of the Valleys of Jequitinhonha and Mucuri (UFVJM), Diamantina, MG, Brazil.,Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil.,Post Graduation Program in Health Science (PPGCS), UFVJM, Diamantina, MG, Brazil
| | - Ricardo Augusto Leoni De Sousa
- Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Ricardo Cardoso Cassilhas
- Department of Physical Education, Federal University of the Valleys of Jequitinhonha and Mucuri (UFVJM), Diamantina, MG, Brazil.,Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil.,Post Graduation Program in Health Science (PPGCS), UFVJM, Diamantina, MG, Brazil
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12
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Global transcriptome analysis of rat hypothalamic arcuate nucleus demonstrates reversal of hypothalamic gliosis following surgically and diet induced weight loss. Sci Rep 2019; 9:16161. [PMID: 31695063 PMCID: PMC6834618 DOI: 10.1038/s41598-019-52257-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 09/27/2019] [Indexed: 12/31/2022] Open
Abstract
The central mechanisms underlying the marked beneficial metabolic effects of bariatric surgery are unclear. Here, we characterized global gene expression in the hypothalamic arcuate nucleus (Arc) in diet-induced obese (DIO) rats following Roux-en-Y gastric bypass (RYGB). 60 days post-RYGB, the Arc was isolated by laser-capture microdissection and global gene expression was assessed by RNA sequencing. RYGB lowered body weight and adiposity as compared to sham-operated DIO rats. Discrete transcriptome changes were observed in the Arc following RYGB, including differential expression of genes associated with inflammation and neuropeptide signaling. RYGB reduced gene expression of glial cell markers, including Gfap, Aif1 and Timp1, confirmed by a lower number of GFAP immunopositive astrocyte profiles in the Arc. Sham-operated weight-matched rats demonstrated a similar glial gene expression signature, suggesting that RYGB and dietary restriction have common effects on hypothalamic gliosis. Considering that RYGB surgery also led to increased orexigenic and decreased anorexigenic gene expression, this may signify increased hunger-associated signaling at the level of the Arc. Hence, induction of counterregulatory molecular mechanisms downstream from the Arc may play an important role in RYGB-induced weight loss.
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13
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Grillo CA, Woodruff JL, Macht VA, Reagan LP. Insulin resistance and hippocampal dysfunction: Disentangling peripheral and brain causes from consequences. Exp Neurol 2019; 318:71-77. [PMID: 31028829 DOI: 10.1016/j.expneurol.2019.04.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 02/06/2023]
Abstract
In the periphery insulin plays a critical role in the regulation of metabolic homeostasis by stimulating glucose uptake into peripheral organs. In the central nervous system (CNS), insulin plays a critical role in the formation of neural circuits and synaptic connections from the earliest stages of development and facilitates and promotes neuroplasticity in the adult brain. Beyond these physiological roles of insulin, a shared feature between the periphery and CNS is that decreases in insulin receptor activity and signaling (i.e. insulin resistance) contributes to the pathological consequences of type 2 diabetes (T2DM) and obesity. Indeed, clinical and preclinical studies illustrate that CNS insulin resistance elicits neuroplasticity deficits that lead to decreases in cognitive function and increased risk of neuropsychiatric disorders. The goals of this review are to provide an overview of the literature that have identified the neuroplasticity deficits observed in T2DM and obesity, as well as to discuss the potential causes and consequences of insulin resistance in the CNS, with a particular focus on how insulin resistance impacts hippocampal neuroplasticity. Interestingly, studies that have examined the effects of hippocampal-specific insulin resistance illustrate that brain insulin resistance may impair neuroplasticity independent of peripheral insulin resistance, thereby supporting the concept that restoration of brain insulin activity is an attractive therapeutic strategy to ameliorate or reverse cognitive decline observed in patients with CNS insulin resistance such as T2DM and Alzheimer's Disease.
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Affiliation(s)
- Claudia A Grillo
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, & Neuroscience, Columbia, SC, USA; WJB Dorn VA Medical Center, Columbia, SC 29209, USA
| | - Jennifer L Woodruff
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, & Neuroscience, Columbia, SC, USA; WJB Dorn VA Medical Center, Columbia, SC 29209, USA
| | - Victoria A Macht
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, & Neuroscience, Columbia, SC, USA; WJB Dorn VA Medical Center, Columbia, SC 29209, USA
| | - Lawrence P Reagan
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, & Neuroscience, Columbia, SC, USA; WJB Dorn VA Medical Center, Columbia, SC 29209, USA.
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14
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Davidson TL, Jones S, Roy M, Stevenson RJ. The Cognitive Control of Eating and Body Weight: It's More Than What You "Think". Front Psychol 2019; 10:62. [PMID: 30814963 PMCID: PMC6381074 DOI: 10.3389/fpsyg.2019.00062] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 01/10/2019] [Indexed: 12/18/2022] Open
Abstract
Over the past decade, a great deal of research has established the importance of cognitive processes in the control of energy intake and body weight. The present paper begins by identifying several of these cognitive processes. We then summarize evidence from human and nonhuman animal models, which shows how excess intake of obesity-promoting Western diet (WD) may have deleterious effects on these cognitive control processes. Findings that these effects may be manifested as early-life deficits in cognitive functioning and may also be associated with the emergence of serious late-life cognitive impairment are described. Consistent with these possibilities, we review evidence, obtained primarily from rodent models, that consuming a WD is associated with the emergence of pathophysiologies in the hippocampus, an important brain substrate for learning, memory, and cognition. The implications of this research for mechanism are discussed within the context of a “vicious-cycle model,” which describes how eating a WD could impair hippocampal function, producing cognitive deficits that promote increased WD intake and body weight gain, which could contribute to further hippocampal dysfunction, cognitive decline, and excess eating and weight gain.
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Affiliation(s)
- Terry L Davidson
- Center for Behavioral Neuroscience, Department of Psychology, American University, Washington, DC, United States
| | - Sabrina Jones
- Center for Behavioral Neuroscience, Department of Psychology, American University, Washington, DC, United States
| | - Megan Roy
- Center for Behavioral Neuroscience, Department of Psychology, American University, Washington, DC, United States
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15
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Ding L, Fang Z, Liu Y, Zhang E, Huang T, Yang L, Wang Z, Huang W. Targeting Bile Acid-Activated Receptors in Bariatric Surgery. Handb Exp Pharmacol 2019; 256:359-378. [PMID: 31144046 DOI: 10.1007/164_2019_229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bariatric surgical procedures, including Roux-en-Y gastric bypass and vertical sleeve gastrectomy, are currently the most effective clinical approaches to achieve a significant and sustainable weight loss. Bariatric surgery also concomitantly improves type 2 diabetes and other metabolic diseases such as nonalcoholic steatohepatitis, cardiovascular diseases, and hyperlipidemia. However, despite the recent exciting progress in the understanding how bariatric surgery works, the underlying molecular mechanisms of bariatric surgery remain largely unknown. Interestingly, bile acids are emerging as potential signaling molecules to mediate the beneficial effects of bariatric surgery. In this review, we summarize the recent findings on bile acids and their activated receptors in mediating the beneficial metabolic effects of bariatric surgery. We also discuss the potential to target bile acid-activated receptors in order to treat obesity and other metabolic diseases.
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Affiliation(s)
- Lili Ding
- Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute of City of Hope, Beckman Research Institute of City of Hope, Duarte, CA, USA.,Shanghai Key Laboratory of Compound Chinese Medicines and The Ministry of Education (MOE) Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhipeng Fang
- Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute of City of Hope, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Yanjun Liu
- Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute of City of Hope, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Eryun Zhang
- Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute of City of Hope, Beckman Research Institute of City of Hope, Duarte, CA, USA.,Shanghai Key Laboratory of Compound Chinese Medicines and The Ministry of Education (MOE) Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Tracy Huang
- Eugene and Roth Roberts Summer Student Academy, City of Hope, Duarte, CA, USA
| | - Li Yang
- Shanghai Key Laboratory of Compound Chinese Medicines and The Ministry of Education (MOE) Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhengtao Wang
- Shanghai Key Laboratory of Compound Chinese Medicines and The Ministry of Education (MOE) Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Wendong Huang
- Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute of City of Hope, Beckman Research Institute of City of Hope, Duarte, CA, USA.
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16
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Central Modulation of Energy Homeostasis and Cognitive Performance After Bariatric Surgery. ADVANCES IN NEUROBIOLOGY 2018; 19:213-236. [PMID: 28933067 DOI: 10.1007/978-3-319-63260-5_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In moderately or morbidly obese patients, bariatric surgery has been proven to be an effective therapeutic approach to control body weight and comorbidities. Surgery-mediated modulation of brain function via modified postoperative secretion of gut peptides and vagal nerve stimulation was identified as an underlying mechanism in weight loss and improvement of weight-related diseases. Increased basal and postprandial plasma levels of gastrointestinal hormones like glucagon-like peptide 1 and peptide YY that act on specific areas of the hypothalamus to reduce food intake, either directly or mediated by the vagus nerve, are observed after surgery while suppression of meal-induced ghrelin release is increased. Hormones released from the adipose tissue like leptin and adiponectin are also affected and leptin plasma levels are reduced in treated patients. Besides homeostatic control of body weight, surgery also changes hedonistic behavior in regard to food intake and cognitive performance involving the limbic system and prefrontal areas.
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17
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Himel AR, Cabral SA, Shaffery JP, Grayson BE. Anxiety behavior and hypothalamic-pituitary-adrenal axis altered in a female rat model of vertical sleeve gastrectomy. PLoS One 2018; 13:e0200026. [PMID: 29979735 PMCID: PMC6034810 DOI: 10.1371/journal.pone.0200026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/18/2018] [Indexed: 01/28/2023] Open
Abstract
Surgical weight loss results in a host of metabolic changes that culminate in net positive health benefit to the patients. However, the psychological impact of these surgeries has not been fully studied. On one hand, surgical weight loss has been reported to improve standard quality of life and resolution of symptoms of depression. But on the other hand, reports of self-harm and increased ER visits for self-harm suggest other psychological difficulties. Inability to handle anxiety following surgical weight loss has alarming potential ramifications for these gastric surgery patients. In the present study, we used models of diet-induced obesity and vertical sleeve gastrectomy (VSG) to ask whether anxiety behavior and hypothalamic-pituitary-adrenal (HPA) axis gene changes were affected by surgical weight loss under two diet regimens: i.e. low-fat diet (LFD) and high-fat diet (HFD). We show reduced exploratory behavior in the open field test but increased time in the open arms of the elevated plus maze. Furthermore, we show increased plasma levels of corticosterone in female VSG recipients in the estrus phase and increased levels of hypothalamic arginine-vasopressin (avp), pro-opiomelanocortin (pomc), and tyrosine hydroxylase (th). We report reduced dopamine receptor D1 (drd1) gene in prefrontal cortex (PFC) in VSG animals in comparison to Sham. Further we report diet-driven changes in stress-relevant gene targets in the hypothalamus (oxt, pomc, crhr1) and adrenal (nr3c1, nr3c2, mc2r). Taken together, these data suggest a significant impact of both surgical weight loss and diet on the HPA axis and further impact on behavior. Additional assessment is necessary to determine whether molecular and hormonal changes of surgical weight loss are the source of these findings.
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Affiliation(s)
- Alexandra R. Himel
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United Status of America
| | - Sharon A. Cabral
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, United Status of America
| | - James P. Shaffery
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, United Status of America
| | - Bernadette E. Grayson
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United Status of America
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18
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Abstract
Obesity has been considered to be a chronic disease that requires medical prevention and treatment. Intriguingly, many factors, including adipose tissue dysfunction, mitochondrial dysfunction, alterations in the muscle fiber phenotype and in the gut microbiota composition, have been identified to be involved in the development of obesity and its associated metabolic disorders (in particular type 2 diabetes mellitus). In this narrative review, we will discuss our current understanding of the relationships of these factors and obesity development, and provide a summary of potential treatments to manage obesity. Level of Evidence Level V, narrative review.
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19
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Vertical sleeve gastrectomy improves indices of metabolic disease in rodent model of surgical menopause. Menopause 2018; 24:426-436. [PMID: 27801704 DOI: 10.1097/gme.0000000000000764] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Although women are the most common recipients of weight loss surgeries for the amelioration of the comorbidities of obesity, few studies have addressed the efficacy of these procedures with specific attention to reproductive stage. Here we ask in a rodent model of vertical sleeve gastrectomy (VSG) whether improvements to metabolic health are realized in women having received surgical menopause. Specifically we were interested in knowing whether rats made menopausal through surgical means would exhibit persistent hepatic steatosis as reported in previously pregnant, freely cycling female VSG rats or if it is resolved as reported in male VSG rats. METHODS All the rats first received ovariectomy (OVX) and then were placed on high-fat diet before either sham or VSG surgery (N = 12, 9) and then were monitored for resolution of obesity-related comorbidities. RESULTS VSG was sufficient to reduce weight and adiposity in OVX females in comparison to obese rats (P < 0.001). Glucose tolerance (P < 0.05) was improved in OVX-VSG females with no change in insulin sensitivity. Both circulating (P < 0.01) and hepatic triglyceride (P < 0.01) levels were also reduced after VSG. Liver integrity was improved in OVX-VSG in comparison to OVX-obese as reflected by reduced aspartate aminotransferase levels (P < 0.05). The ability of mitochondria to generate adenosine triphosphate was maintained, and an increase in complex IV may decrease the production of mitochondrial reactive oxygen species. CONCLUSIONS Taken together, VSG in OVX rats experience many positive benefits including the resolution of hepatic steatosis that persists in reproductively intact female rats after VSG.
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20
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Abstract
Increased body mass is directly associated with reduced cognitive function. The aim of this study was to systematically review the effect of bariatric weight loss surgery on cognitive function. A comprehensive and unrestricted literature search was conducted using the following databases: MEDLINE, EMBASE, PubMed, Scopus, Web of Sciences, and the Cochrane Library. A total of 414 publications were identified, of which 18 were included in the final review. Cognitive function as measured by a number of different assessment tools was shown to improve following surgically induced weight loss in most studies. Significant and rapid weight loss resulting from bariatric surgery is associated with prompt and sustained improvements in cognitive function including memory, executive function, and cognitive control.
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21
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Stefanidis A, Oldfield BJ. Neuroendocrine mechanisms underlying bariatric surgery: Insights from human studies and animal models. J Neuroendocrinol 2017; 29. [PMID: 28887853 DOI: 10.1111/jne.12534] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/31/2017] [Accepted: 09/01/2017] [Indexed: 02/06/2023]
Abstract
Obesity has reached epidemic proportions and, to date, bariatric surgery remains the only effective treatment for morbid obesity in terms of its capacity to achieve durable weight loss. Bariatric surgery procedures, including Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB) and sleeve gastrectomy (SG), have been the primary procedures conducted over the past decade, with SG increasing in popularity over the past 5 years at the expense of both RYGB and AGB. Although these procedures were initially proposed to function via restrictive or malabsorptive mechanisms, it is now clear that profound physiological changes underlie the metabolic improvements in patients who undergo bariatric surgery. Data generated in human patients and animal models highlight the rapid and sustained changes in gut hormones that coincide with these procedures. Furthermore, recent studies highlight the involvement of the nervous system, specifically the vagus nerve, in mediating the reduction in appetite and food intake following bariatric surgery. What is unclear is where these pathways converge and interact within the gut-brain axis and whether vagally-mediated circuits are sufficient to drive the metabolic sequalae following bariatric surgery.
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Affiliation(s)
- A Stefanidis
- Department of Physiology, Monash University, Clayton, VIC, Australia
| | - B J Oldfield
- Metabolic Disease and Obesity Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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22
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Guillemot-Legris O, Muccioli GG. Obesity-Induced Neuroinflammation: Beyond the Hypothalamus. Trends Neurosci 2017; 40:237-253. [DOI: 10.1016/j.tins.2017.02.005] [Citation(s) in RCA: 292] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 12/21/2022]
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23
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Hargrave SL, Jones S, Davidson TL. The Outward Spiral: A vicious cycle model of obesity and cognitive dysfunction. Curr Opin Behav Sci 2016; 9:40-46. [PMID: 26998507 DOI: 10.1016/j.cobeha.2015.12.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Chronic failure to suppress intake during states of positive energy balance leads to weight gain and obesity. The ability to use context - including interoceptive satiety states - to inhibit responding to previously rewarded cues appears to depend on the functional integrity of the hippocampus. Recent evidence implicates energy dense Western diets in several types of hippocampal dysfunction, including reduced expression of neurotrophins and nutrient transporters, increased inflammation, microglial activation, and blood brain barrier permeability. The functional consequences of such insults include impairments in an animal's ability to modulate responding to a previously reinforced cues. We propose that such deficits promote overeating, which can further exacerbate hippocampal dysfunction and thus initiate a vicious cycle of both obesity and progressive cognitive decline.
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Affiliation(s)
- Sara L Hargrave
- Center for Behavioral Neuroscience, Department of Psychology. American University. Washington, DC 20016, USA
| | - Sabrina Jones
- Center for Behavioral Neuroscience, Department of Psychology. American University. Washington, DC 20016, USA
| | - Terry L Davidson
- Center for Behavioral Neuroscience, Department of Psychology. American University. Washington, DC 20016, USA
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24
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Fadel JR, Reagan LP. Stop signs in hippocampal insulin signaling: the role of insulin resistance in structural, functional and behavioral deficits. Curr Opin Behav Sci 2015; 9:47-54. [PMID: 26955646 DOI: 10.1016/j.cobeha.2015.12.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In peripheral tissues insulin activates signaling cascades to facilitate glucose uptake from the blood into tissues like liver, muscle and fat. While insulin appears to play a minor role in the regulation of glucose uptake in the central nervous system (CNS), insulin is known to play a major role in regulating synaptic plasticity in brain regions like the hippocampus. The concept that insulin regulates hippocampal neuroplasticity is further supported from animal models of type 2 diabetes (T2DM) and Alzheimer's disease (AD). The goal of this review is to provide an overview of these studies, as well as the studies that have examined whether deficits in hippocampal insulin signaling are amenable to intervention strategies.
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Affiliation(s)
- Jim R Fadel
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Lawrence P Reagan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA; WJB Dorn Veterans Affairs Medical Center, Columbia, SC, USA
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25
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Abstract
Clinical studies suggest a link between type 2 diabetes mellitus (T2DM) and insulin resistance (IR) and cognitive dysfunction, but there are significant gaps in our knowledge of the mechanisms underlying this relationship. Animal models of IR help to bridge these gaps and point to hippocampal IR as a potential mediator of cognitive dysfunction in T2DM, as well as in Alzheimer disease (AD). This Review highlights these observations and discusses intervention studies which suggest that the restoration of insulin activity in the hippocampus may be an effective strategy to alleviate the cognitive decline associated with T2DM and AD.
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26
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Davidson TL, Tracy AL, Schier LA, Swithers SE. A view of obesity as a learning and memory disorder. JOURNAL OF EXPERIMENTAL PSYCHOLOGY-ANIMAL LEARNING AND COGNITION 2015; 40:261-79. [PMID: 25453037 DOI: 10.1037/xan0000029] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This articles describes how a cascade of associative relationships involving the sensory properties of foods, the nutritional consequences of their consumption, and perceived internal states may play an important role in the learned control of energy intake and body weight regulation. In addition, we describe ways in which dietary factors in the current environment can promote excess energy intake and body weight gain by degrading these relationships or by interfering with the neural substrates that underlie the ability of animals to use them to predict the nutritive or energetic consequences of intake. We propose that an expanded appreciation of the diversity of orosensory, gastrointestinal, and energy state signals about which animals learn, combined with a greater understanding of predictive relationships in which these cues are embedded, will help generate new information and novel approaches to addressing the current global problems of obesity and metabolic disease.
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27
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Sample CH, Martin AA, Jones S, Hargrave SL, Davidson TL. Western-style diet impairs stimulus control by food deprivation state cues: Implications for obesogenic environments. Appetite 2015; 93:13-23. [PMID: 26002280 DOI: 10.1016/j.appet.2015.05.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 04/03/2015] [Accepted: 05/15/2015] [Indexed: 12/23/2022]
Abstract
In western and westernized societies, large portions of the population live in what are considered to be "obesogenic" environments. Among other things, obesogenic environments are characterized by a high prevalence of external cues that are associated with highly palatable, energy-dense foods. One prominent hypothesis suggests that these external cues become such powerful conditioned elicitors of appetitive and eating behavior that they overwhelm the internal, physiological mechanisms that serve to maintain energy balance. The present research investigated a learning mechanism that may underlie this loss of internal relative to external control. In Experiment 1, rats were provided with both auditory cues (external stimuli) and varying levels of food deprivation (internal stimuli) that they could use to solve a simple discrimination task. Despite having access to clearly discriminable external cues, we found that the deprivation cues gained substantial discriminative control over conditioned responding. Experiment 2 found that, compared to standard chow, maintenance on a "western-style" diet high in saturated fat and sugar weakened discriminative control by food deprivation cues, but did not impair learning when external cues were also trained as relevant discriminative signals for sucrose. Thus, eating a western-style diet contributed to a loss of internal control over appetitive behavior relative to external cues. We discuss how this relative loss of control by food deprivation signals may result from interference with hippocampal-dependent learning and memory processes, forming the basis of a vicious-cycle of excessive intake, body weight gain, and progressive cognitive decline that may begin very early in life.
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Affiliation(s)
- Camille H Sample
- Center for Behavioral Neuroscience and Department of Psychology, American University, Washington, DC, USA
| | - Ashley A Martin
- Nutrition and Behaviour Unit, School of Experimental Psychology, University of Bristol, Bristol, UK
| | - Sabrina Jones
- Center for Behavioral Neuroscience and Department of Psychology, American University, Washington, DC, USA
| | - Sara L Hargrave
- Center for Behavioral Neuroscience and Department of Psychology, American University, Washington, DC, USA
| | - Terry L Davidson
- Center for Behavioral Neuroscience and Department of Psychology, American University, Washington, DC, USA.
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28
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Sleeve gastrectomy and Roux-en-Y gastric bypass alter the gut-brain communication. Neural Plast 2015; 2015:601985. [PMID: 25722893 PMCID: PMC4333325 DOI: 10.1155/2015/601985] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 12/15/2022] Open
Abstract
This study investigated the anatomical integrity of vagal innervation of the gastrointestinal tract following vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) operations. The retrograde tracer fast blue (FB) was injected into the stomach to label vagal neurons originating from nodose ganglion (NG) and dorsal motor nucleus of the vagus (DMV). Microglia activation was determined by quantifying changes in the fluorescent staining of hindbrain sections against an ionizing calcium adapter binding molecule 1 (Iba1). Reorganization of vagal afferents in the hindbrain was studied by fluorescent staining against isolectin 4 (IB4). The density of Iba1- and IB4-immunoreactivity was analyzed using Nikon Elements software. There was no difference in the number of FB-labeled neurons located in NG and DMV between VSG and VSG-sham rats. RYGB, but not RYGB-sham rats, showed a dramatic reduction in number of FB-labeled neurons located in the NG and DMV. VSG increased, while the RYGB operation decreased, the density of vagal afferents in the nucleus tractus solitarius (NTS). The RYGB operation, but not the VSG procedure, significantly activated microglia in the NTS and DMV. Results of this study show that the RYGB, but not the VSG procedure, triggers microglia activation in vagal structures and remodels gut-brain communication.
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29
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Ménard C, Gaudreau P, Quirion R. Signaling pathways relevant to cognition-enhancing drug targets. Handb Exp Pharmacol 2015; 228:59-98. [PMID: 25977080 DOI: 10.1007/978-3-319-16522-6_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aging is generally associated with a certain cognitive decline. However, individual differences exist. While age-related memory deficits can be observed in humans and rodents in the absence of pathological conditions, some individuals maintain intact cognitive functions up to an advanced age. The mechanisms underlying learning and memory processes involve the recruitment of multiple signaling pathways and gene expression, leading to adaptative neuronal plasticity and long-lasting changes in brain circuitry. This chapter summarizes the current understanding of how these signaling cascades could be modulated by cognition-enhancing agents favoring memory formation and successful aging. It focuses on data obtained in rodents, particularly in the rat as it is the most common animal model studied in this field. First, we will discuss the role of the excitatory neurotransmitter glutamate and its receptors, downstream signaling effectors [e.g., calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase C (PKC), extracellular signal-regulated kinases (ERK), mammalian target of rapamycin (mTOR), cAMP response element-binding protein (CREB)], associated immediate early gene (e.g., Homer 1a, Arc and Zif268), and growth factors [insulin-like growth factors (IGFs) and brain-derived neurotrophic factor (BDNF)] in synaptic plasticity and memory formation. Second, the impact of the cholinergic system and related modulators on memory will be briefly reviewed. Finally, since dynorphin neuropeptides have recently been associated with memory impairments in aging, it is proposed as an attractive target to develop novel cognition-enhancing agents.
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Affiliation(s)
- Caroline Ménard
- Douglas Mental Health University Institute, McGill University, Perry Pavilion, 6875 LaSalle Boulevard, Montreal, QC, Canada, H4H 1R3
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Farr OM, Tsoukas MA, Mantzoros CS. Leptin and the brain: influences on brain development, cognitive functioning and psychiatric disorders. Metabolism 2015; 64:114-30. [PMID: 25092133 DOI: 10.1016/j.metabol.2014.07.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 06/16/2014] [Accepted: 07/05/2014] [Indexed: 12/20/2022]
Abstract
Receptors of leptin, the prototypical adipokine, are expressed throughout the cortex and several other areas of the brain. Although typically studied for its role in energy intake and expenditure, leptin plays a critical role in many other neurocognitive processes and interacts with various other hormones and neurotransmitters to perform these functions. Here, we review the literature on how leptin influences brain development, neural degradation, Alzheimer's disease, psychiatric disorders, and more complicated cognitive functioning and feeding behaviors. We also discuss modulators of leptin and the leptin receptor as they relate to normal cognitive functioning and may mediate some of the actions of leptin in the brain. Although we are beginning to better understand the critical role leptin plays in normal cognitive functioning, there is much to be discovered.
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Affiliation(s)
- Olivia M Farr
- Division of Endocrinology, Boston VA Healthcare System/Harvard Medical School, Boston, MA 02215.
| | - Michael A Tsoukas
- Division of Endocrinology, Boston VA Healthcare System/Harvard Medical School, Boston, MA 02215
| | - Christos S Mantzoros
- Division of Endocrinology, Boston VA Healthcare System/Harvard Medical School, Boston, MA 02215
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Hale MW, Spencer SJ, Conti B, Jasoni CL, Kent S, Radler ME, Reyes TM, Sominsky L. Diet, behavior and immunity across the lifespan. Neurosci Biobehav Rev 2014; 58:46-62. [PMID: 25524877 DOI: 10.1016/j.neubiorev.2014.12.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 11/10/2014] [Accepted: 12/04/2014] [Indexed: 02/07/2023]
Abstract
It is increasingly appreciated that perinatal events can set an organism on a life-long trajectory for either health or disease, resilience or risk. One early life variable that has proven critical for optimal development is the nutritional environment in which the organism develops. Extensive research has documented the effects of both undernutrition and overnutrition, with strong links evident for an increased risk for obesity and metabolic disorders, as well as adverse mental health outcomes. Recent work has highlighted a critical role of the immune system, in linking diet with long term health and behavioral outcomes. The present review will summarize the recent literature regarding the interactions of diet, immunity, and behavior.
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Affiliation(s)
- Matthew W Hale
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - Sarah J Spencer
- School of Health Sciences and Health Innovations Research Institute (HIRi), RMIT University, Melbourne, VIC, Australia.
| | - Bruno Conti
- The Scripps Research Institute, La Jolla, CA, USA
| | - Christine L Jasoni
- Centre for Neuroendocrinology, Gravida: National Centre for Growth and Development, Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Stephen Kent
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - Morgan E Radler
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - Teresa M Reyes
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Luba Sominsky
- School of Health Sciences and Health Innovations Research Institute (HIRi), RMIT University, Melbourne, VIC, Australia
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Grayson BE, Hakala-Finch AP, Kekulawala M, Laub H, Egan AE, Ressler IB, Woods SC, Herman JP, Seeley RJ, Benoit SC, Ulrich-Lai YM. Weight loss by calorie restriction versus bariatric surgery differentially regulates the hypothalamo-pituitary-adrenocortical axis in male rats. Stress 2014; 17:484-93. [PMID: 25238021 PMCID: PMC4415587 DOI: 10.3109/10253890.2014.967677] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Behavioral modifications for the treatment of obesity, including caloric restriction, have notoriously low long-term success rates relative to bariatric weight-loss surgery. The reasons for the difference in sustained weight loss are not clear. One possibility is that caloric restriction alone activates the stress-responsive hypothalamo-pituitary-adrenocortical (HPA) axis, undermining the long-term maintenance of weight loss, and that this is abrogated after bariatric surgery. Accordingly, we compared the HPA response to weight loss in five groups of male rats: (1) high-fat diet-induced obese (DIO) rats treated with Roux-en-Y gastric bypass surgery (RYGB, n = 7), (2) DIO rats treated with vertical sleeve gastrectomy (VSG, n = 11), (3) DIO rats given sham surgery and subsequently restricted to the food intake of the VSG/RYGB groups (Pair-fed, n = 11), (4) ad libitum-fed DIO rats given sham surgery (Obese, n = 11) and (5) ad libitum chow-fed rats given sham surgery (Lean, n = 12). Compared with Lean controls, food-restricted rats exhibited elevated morning (nadir) non-stress plasma corticosterone concentration and increased hypothalamic corticotropin-releasing hormone and vasopressin mRNA expression, indicative of basal HPA activation. This was largely prevented when weight loss was achieved by bariatric surgery. DIO increased HPA activation by acute (novel environment) stress and this was diminished by bariatric surgery-, but not pair-feeding-, induced weight loss. These results indicate that the HPA axis is differentially affected by weight loss from caloric restriction versus bariatric surgery, and this may contribute to the differing long-term effectiveness of these two weight-loss approaches.
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Affiliation(s)
- Bernadette E. Grayson
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati School of Medicine, Cincinnati, OH 45237
- Corresponding author, request for reprints: Bernadette E. Grayson, Metabolic Diseases Institute, University of Cincinnati, 2170 E. Galbraith Rd., Cincinnati, OH 45237, , ph: 513-748-4850, fax: 513-297-0966
| | - Andrew P. Hakala-Finch
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - Melani Kekulawala
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - Holly Laub
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - Ann E. Egan
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - Ilana B. Ressler
- Department of Obstetrics and Gynecology, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - Stephen C. Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - James P. Herman
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - Randy J. Seeley
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - Stephen C. Benoit
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati School of Medicine, Cincinnati, OH 45237
| | - Yvonne M. Ulrich-Lai
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati School of Medicine, Cincinnati, OH 45237
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Radler ME, Wright BJ, Walker FR, Hale MW, Kent S. Calorie restriction increases lipopolysaccharide-induced neuropeptide Y immunolabeling and reduces microglial cell area in the arcuate hypothalamic nucleus. Neuroscience 2014; 285:236-47. [PMID: 25446356 DOI: 10.1016/j.neuroscience.2014.11.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/20/2014] [Accepted: 11/04/2014] [Indexed: 11/30/2022]
Abstract
Calorie restriction (CR) increases longevity and elicits many health promoting benefits including delaying immunosenescence and reducing the incidence of age-related diseases. Although the mechanisms underlying the health-enhancing effects of CR are not known, a likely contributing factor is alterations in immune system functioning. CR suppresses lipopolysaccharide (LPS)-induced release of pro-inflammatory cytokines, blocks LPS-induced fever, and shifts hypothalamic signaling pathways to an anti-inflammatory bias. Furthermore, we have recently shown that CR attenuates LPS-stimulated microglial activation in the hypothalamic arcuate nucleus (ARC), a brain region containing neurons that synthesize neuropeptide Y (NPY), an orexigenic neuropeptide that is upregulated by a CR diet and has anti-inflammatory properties. To determine if increased NPY expression in the ARC following CR was associated with changes in microglial activation, a set of brain sections from mice that were exposed to 50% CR or ad libitum feeding for 28 days before being injected with LPS were immunostained for NPY. The density of NPY-immunolabeling was assessed across the rostrocaudal extent of the ARC and hypothalamic paraventricular nucleus (PVN). An adjacent set of sections were immunostained for ionized calcium-binding adapter molecule-1 (Iba1) and immunostained microglia in the ARC were digitally reconstructed to investigate the effects of CR on microglial morphology. We demonstrated that exposure to CR increased NPY expression in the ARC, but not the PVN. Digital reconstruction of microglia revealed that LPS increased Iba1 intensity in ad libitum fed mice but had no effect on Iba1 intensity in CR mice. CR also decreased the size of ARC microglial cells following LPS. Correlational analyses revealed strong associations between NPY and body temperature, and body temperature and microglia area. Together these results suggest that CR-induced changes in NPY are not directly involved in the suppression of LPS-induced microglial activation, however, NPY may indirectly affect microglial morphology through changes in body temperature.
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Affiliation(s)
- M E Radler
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - B J Wright
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - F R Walker
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, NSW, Australia
| | - M W Hale
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - S Kent
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia.
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Miller AA, Spencer SJ. Obesity and neuroinflammation: a pathway to cognitive impairment. Brain Behav Immun 2014; 42:10-21. [PMID: 24727365 DOI: 10.1016/j.bbi.2014.04.001] [Citation(s) in RCA: 465] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/19/2014] [Accepted: 04/01/2014] [Indexed: 12/31/2022] Open
Abstract
Obesity is a growing problem worldwide and is associated with a range of comorbidities, including cognitive dysfunction. In this review we will address the evidence that obesity and high fat feeding can lead to cognitive dysfunction. We will also examine the idea that obesity-associated systemic inflammation leads to inflammation within the brain, particularly the hypothalamus, and that this is partially responsible for these negative cognitive outcomes. Thus, obesity, and high fat feeding, lead to systemic inflammation and excess circulating free fatty acids. Circulating cytokines, free fatty acids and immune cells reach the brain at the level of the hypothalamus and initiate local inflammation, including microglial proliferation. This local inflammation likely causes synaptic remodeling and neurodegeneration within the hypothalamus, altering internal hypothalamic circuitry and hypothalamic outputs to other brain regions. The result is disruption to cognitive function mediated by regions such as hippocampus, amygdala, and reward-processing centers. Central inflammation is also likely to affect these regions directly. Thus, central inflammation in obesity leads not just to disruption of hypothalamic satiety signals and perpetuation of overeating, but also to negative outcomes on cognition.
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Affiliation(s)
- Alyson A Miller
- School of Medical Sciences and Health Innovations Research Institute (HIRi), RMIT University, Melbourne, Vic., Australia
| | - Sarah J Spencer
- School of Health Sciences and HIRi, RMIT University, Melbourne, Vic., Australia.
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Long-term changes in the ghrelin-CB1R axis associated with the maintenance of lower body weight after sleeve gastrectomy. Nutr Diabetes 2014; 4:e127. [PMID: 25027795 PMCID: PMC5189929 DOI: 10.1038/nutd.2014.24] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/08/2014] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES In the hypothalamus, the molecular actions of receptors for growth hormone secretagogue (ghrelin) receptor-GHSR, leptin receptor-b (LEPRb), Melanocortin-4 receptor (MC4R) and Cannabinoid-1 receptor (CB1R) regulate energy homeostasis and body weight. We hypothesized that the acute loss of stomach tissue upon sleeve gastrectomy (SG), performed to treat obesity, imposes modulations on the expression of these receptors in the brain to sustain weight loss. METHODS Rats, induced to obesity with high-fat diet were randomized to SG- or sham-operation groups and killed at 30 or 90 days post surgery, when the expression of Ghrl, Mboat4 and Cnr1 in the stomach, and Ghsr, Leprb, Mc4r and Cnr1 in distinct brain areas was assessed by reverse transcription-PCR and western blotting. RESULTS SG acutely reduced body weight and fat mass and suppressed the remnant stomach mRNA levels of preproghrelin and ghrelin O-acyltransferase, which correlated well with long-term decreases in CB1R mRNA. In the hypothalamus, increases in GHSR and decreases in CB1R and LEPRb by 30 days were followed by further downregulation of CB1R and an increase in MC4R by 90 days. CONCLUSIONS Post SG, acyl-ghrelin initiates a temporal hierarchy of molecular events in the gut-brain axis that may both explain the sustained lower body weight and suggest intervention into the cannabinoid pathways for additional therapeutic benefits.
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Martin AA, Davidson TL. Human cognitive function and the obesogenic environment. Physiol Behav 2014; 136:185-93. [PMID: 24631299 DOI: 10.1016/j.physbeh.2014.02.062] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 02/17/2014] [Accepted: 02/21/2014] [Indexed: 12/23/2022]
Abstract
Evidence is accumulating which suggests that, in addition to leading to unprecedented rates of obesity, the current food environment is contributing to the development of cognitive impairment and dementia. Recent experimental research indicates that many of the cognitive deficits associated with obesity involve fundamental inhibitory processes that have important roles in the control of food intake, implicating these cognitive impairments as a risk factor for weight gain. Here, we review experiments that link obesity with deficits in memory, attentional, and behavioral control and contemplate how these deficits may predispose individuals to overeat. Specifically, we discuss how deficits in inhibitory control may reduce one's ability to resist eating when confronted with the variety of foods and food cues that are ubiquitous in today's environment. Special attention is given to the importance of memory inhibition to the control of eating and appetitive behavior, and the role of the hippocampus in this process. We also discuss the potential etiology of both obesity and obesity-related cognitive impairment, highlighting non-human animal research which links both of these effects to the consumption of the modern "Western" diet that is high in saturated fats and simple carbohydrates. We conclude that part of what makes the current food environment "obesogenic" is the increased presence of food cues and the increased consumption of a diet which compromises our ability to resist those cues. Improving control over food-related cognitive processing may be useful not only for combating the obesity epidemic but also for minimizing the risk of serious cognitive disorder later in life.
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Affiliation(s)
- Ashley A Martin
- School of Experimental Psychology, Nutrition and Behaviour Unit, University of Bristol, Bristol, UK.
| | - Terry L Davidson
- Department of Psychology and Center for Behavioral Neuroscience, American University, Washington, DC, United States
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Tucker RM, Edlinger C, Craig BA, Mattes RD. Associations between BMI and fat taste sensitivity in humans. Chem Senses 2014; 39:349-57. [PMID: 24591531 DOI: 10.1093/chemse/bju006] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The objective of this study was to examine the reliability of associations between fat taste, hunger, dietary fat intake, and body mass index (BMI). Detection thresholds for oleic acid (OA) were obtained during each of 7 consecutive visits using a modified staircase procedure. Participants were 48 (N = 17 male; N = 31 female) healthy adults (mean age: 28.5 ± 10.4 years) with BMI's ranging from 18.9 to 47.2 (≥ 25 kg · m(-2), N = 24). OA detection thresholds and self-reported hunger (100-mm visual analog scale) were assessed at each visit. BMI and dietary fat intake (Block Rapid Fat Screener) were determined at baseline. There was a significant decrease of threshold concentration over repeated trials among lean and overweight (BMI between 25.0 and 29.9 kg · m(-2)) participants but not in the obese. Combining the lean and overweight and contrasting their responses to the obese revealed the lean plus overweight group to be significantly more sensitive at visits 6 and 7. No change of threshold sensitivity or correlation with fat intake was observed in the obese participants unlike findings in the lean and lean plus overweight participants. Correlations between saturated fat intake and threshold sensitivity were positive (greater intake associated with higher thresholds) at baseline for the group, with additional correlations observed among the lean plus overweight but not in the obese, leaving open questions about the nutritional significance of the association. No significant associations were observed between sensitivity to OA and hunger. Repeated testing is required to assess associations between fat taste and other outcome variables.
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Affiliation(s)
- Robin M Tucker
- Department of Nutrition Science, Purdue University, 700W. State Street, West Lafayette, IN 47907, USA.
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Mokadem M, Zechner JF, Margolskee RF, Drucker DJ, Aguirre V. Effects of Roux-en-Y gastric bypass on energy and glucose homeostasis are preserved in two mouse models of functional glucagon-like peptide-1 deficiency. Mol Metab 2013; 3:191-201. [PMID: 24634822 DOI: 10.1016/j.molmet.2013.11.010] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 11/21/2013] [Accepted: 11/25/2013] [Indexed: 12/13/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) secretion is greatly enhanced after Roux-en-Y gastric bypass (RYGB). While intact GLP-1exerts its metabolic effects via the classical GLP-1 receptor (GLP-1R), proteolytic processing of circulating GLP-1 yields metabolites such as GLP-1(9-36)amide/GLP-1(28-36)amide, that exert similar effects independent of the classical GLP-1R. We investigated the hypothesis that GLP-1, acting via these metabolites or through its known receptor, is required for the beneficial effects of RYGB using two models of functional GLP-1 deficiency - α-gustducin-deficient (α-Gust (-/-)) mice, which exhibit attenuated nutrient-stimulated GLP-1 secretion, and GLP-1R-deficient mice. We show that the effect of RYGB to enhance glucose-stimulated GLP-1 secretion was greatly attenuated in α-Gust (-/-) mice. In both genetic models, RYGB reduced body weight and improved glucose homeostasis to levels observed in lean control mice. Therefore, GLP-1, acting through its classical GLP-1R or its bioactive metabolites, does not seem to be involved in the effects of RYGB on body weight and glucose homeostasis.
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Affiliation(s)
- Mohamad Mokadem
- Center for Hypothalamic Research, Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Juliet F Zechner
- Center for Hypothalamic Research, Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Robert F Margolskee
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Daniel J Drucker
- Department of Medicine, Mt. Sinai Hospital, Samuel Lunenfeld Research Institute, University of Toronto, 600 University Avenue, Toronto, Ontario, Canada M5G 1X5
| | - Vincent Aguirre
- Center for Hypothalamic Research, Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
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