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Rhea EM, Leclerc M, Yassine HN, Capuano AW, Tong H, Petyuk VA, Macauley SL, Fioramonti X, Carmichael O, Calon F, Arvanitakis Z. State of the Science on Brain Insulin Resistance and Cognitive Decline Due to Alzheimer's Disease. Aging Dis 2024; 15:1688-1725. [PMID: 37611907 PMCID: PMC11272209 DOI: 10.14336/ad.2023.0814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) is common and increasing in prevalence worldwide, with devastating public health consequences. While peripheral insulin resistance is a key feature of most forms of T2DM and has been investigated for over a century, research on brain insulin resistance (BIR) has more recently been developed, including in the context of T2DM and non-diabetes states. Recent data support the presence of BIR in the aging brain, even in non-diabetes states, and found that BIR may be a feature in Alzheimer's disease (AD) and contributes to cognitive impairment. Further, therapies used to treat T2DM are now being investigated in the context of AD treatment and prevention, including insulin. In this review, we offer a definition of BIR, and present evidence for BIR in AD; we discuss the expression, function, and activation of the insulin receptor (INSR) in the brain; how BIR could develop; tools to study BIR; how BIR correlates with current AD hallmarks; and regional/cellular involvement of BIR. We close with a discussion on resilience to both BIR and AD, how current tools can be improved to better understand BIR, and future avenues for research. Overall, this review and position paper highlights BIR as a plausible therapeutic target for the prevention of cognitive decline and dementia due to AD.
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Affiliation(s)
- Elizabeth M Rhea
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA.
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA.
| | - Manon Leclerc
- Faculty of Pharmacy, Laval University, Quebec, Quebec, Canada.
- Neuroscience Axis, CHU de Québec Research Center - Laval University, Quebec, Quebec, Canada.
| | - Hussein N Yassine
- Departments of Neurology and Medicine, University of Southern California, Los Angeles, CA 90033, USA.
| | - Ana W Capuano
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612, USA.
| | - Han Tong
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612, USA.
| | - Vladislav A Petyuk
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| | - Shannon L Macauley
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA.
| | - Xavier Fioramonti
- International Associated Laboratory OptiNutriBrain, Bordeaux, France and Quebec, Canada.
- Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33000 Bordeaux, France.
| | - Owen Carmichael
- Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
| | - Frederic Calon
- Faculty of Pharmacy, Laval University, Quebec, Quebec, Canada.
- Neuroscience Axis, CHU de Québec Research Center - Laval University, Quebec, Quebec, Canada.
- International Associated Laboratory OptiNutriBrain, Bordeaux, France and Quebec, Canada.
| | - Zoe Arvanitakis
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612, USA.
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Nogueras‐Ortiz CJ, Eren E, Yao P, Calzada E, Dunn C, Volpert O, Delgado‐Peraza F, Mustapic M, Lyashkov A, Rubio FJ, Vreones M, Cheng L, You Y, Hill AF, Ikezu T, Eitan E, Goetzl EJ, Kapogiannis D. Single-extracellular vesicle (EV) analyses validate the use of L1 Cell Adhesion Molecule (L1CAM) as a reliable biomarker of neuron-derived EVs. J Extracell Vesicles 2024; 13:e12459. [PMID: 38868956 PMCID: PMC11170079 DOI: 10.1002/jev2.12459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 04/15/2024] [Accepted: 05/10/2024] [Indexed: 06/14/2024] Open
Abstract
Isolation of neuron-derived extracellular vesicles (NDEVs) with L1 Cell Adhesion Molecule (L1CAM)-specific antibodies has been widely used to identify blood biomarkers of CNS disorders. However, full methodological validation requires demonstration of L1CAM in individual NDEVs and lower levels or absence of L1CAM in individual EVs from other cells. Here, we used multiple single-EV techniques to establish the neuronal origin and determine the abundance of L1CAM-positive EVs in human blood. L1CAM epitopes of the ectodomain are shown to be co-expressed on single-EVs with the neuronal proteins β-III-tubulin, GAP43, and VAMP2, the levels of which increase in parallel with the enrichment of L1CAM-positive EVs. Levels of L1CAM-positive EVs carrying the neuronal proteins VAMP2 and β-III-tubulin range from 30% to 63%, in contrast to 0.8%-3.9% of L1CAM-negative EVs. Plasma fluid-phase L1CAM does not bind to single-EVs. Our findings support the use of L1CAM as a target for isolating plasma NDEVs and leveraging their cargo to identify biomarkers reflecting neuronal function.
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Affiliation(s)
- Carlos J Nogueras‐Ortiz
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | - Erden Eren
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | - Pamela Yao
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | - Elizabeth Calzada
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | - Christopher Dunn
- Flow Cytometry Unit, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | | | - Francheska Delgado‐Peraza
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | - Maja Mustapic
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | - Alexey Lyashkov
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | - F Javier Rubio
- Neuronal Ensembles in Addiction Section, Behavioral Neuroscience Research BranchIntramural Research Program/National Institute on Drug Abuse/National Institutes of HealthBaltimoreMarylandUSA
| | - Michael Vreones
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
| | - Lesley Cheng
- La Trobe Institute for Molecular ScienceLa Trobe UniversityBundooraVictoriaAustralia
| | - Yang You
- Department of NeuroscienceMayo ClinicJacksonvilleFloridaUSA
- Department of Pharmacology and Experimental TherapeuticsBoston University School of MedicineBostonMassachusettsUSA
| | - Andrew F Hill
- La Trobe Institute for Molecular ScienceLa Trobe UniversityBundooraVictoriaAustralia
- Institute for Health and SportVictoria UniversityMelbourneVictoriaAustralia
| | - Tsuneya Ikezu
- Department of NeuroscienceMayo ClinicJacksonvilleFloridaUSA
- Department of Pharmacology and Experimental TherapeuticsBoston University School of MedicineBostonMassachusettsUSA
| | | | - Edward J Goetzl
- Department of MedicineUniversity of CaliforniaSan FranciscoCaliforniaUSA
- San Francisco Campus for Jewish LivingSan FranciscoCaliforniaUSA
| | - Dimitrios Kapogiannis
- Laboratory of Clinical Investigation, Intramural Research ProgramNational Institute on Aging, National Institutes of Health (NIA/NIH)BaltimoreMarylandUSA
- Department of NeurologyJohns Hopkins School of MedicineBaltimoreMarylandUSA
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Cai M, Wan J, Cai K, Li S, Du X, Song H, Sun W, Hu J. The mitochondrial quality control system: a new target for exercise therapeutic intervention in the treatment of brain insulin resistance-induced neurodegeneration in obesity. Int J Obes (Lond) 2024; 48:749-763. [PMID: 38379083 DOI: 10.1038/s41366-024-01490-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/22/2024]
Abstract
Obesity is a major global health concern because of its strong association with metabolic and neurodegenerative diseases such as diabetes, dementia, and Alzheimer's disease. Unfortunately, brain insulin resistance in obesity is likely to lead to neuroplasticity deficits. Since the evidence shows that insulin resistance in brain regions abundant in insulin receptors significantly alters mitochondrial efficiency and function, strategies targeting the mitochondrial quality control system may be of therapeutic and practical value in obesity-induced cognitive decline. Exercise is considered as a powerful stimulant of mitochondria that improves insulin sensitivity and enhances neuroplasticity. It has great potential as a non-pharmacological intervention against the onset and progression of obesity associated neurodegeneration. Here, we integrate the current knowledge of the mechanisms of neurodegenration in obesity and focus on brain insulin resistance to explain the relationship between the impairment of neuronal plasticity and mitochondrial dysfunction. This knowledge was synthesised to explore the exercise paradigm as a feasible intervention for obese neurodegenration in terms of improving brain insulin signals and regulating the mitochondrial quality control system.
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Affiliation(s)
- Ming Cai
- Jinshan District Central Hospital affiliated to Shanghai University of Medicine & Health Sciences, Shanghai, 201599, China
| | - Jian Wan
- Department of Emergency and Critical Care Medicine, Shanghai Pudong New Area People's Hospital, Shanghai, 201299, China
| | - Keren Cai
- College of Rehabilitation Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, 201318, China
| | - Shuyao Li
- College of Rehabilitation Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, 201318, China
| | - Xinlin Du
- College of Rehabilitation Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, 201318, China
| | - Haihan Song
- Central Lab, Shanghai Key Laboratory of Pathogenic Fungi Medical Testing, Shanghai Pudong New Area People's Hospital, Shanghai, 201299, China
| | - Wanju Sun
- Central Lab, Shanghai Key Laboratory of Pathogenic Fungi Medical Testing, Shanghai Pudong New Area People's Hospital, Shanghai, 201299, China.
| | - Jingyun Hu
- Central Lab, Shanghai Key Laboratory of Pathogenic Fungi Medical Testing, Shanghai Pudong New Area People's Hospital, Shanghai, 201299, China.
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Arvanitakis Z, Capuano AW, Tong H, Mehta RI, Anokye-Danso F, Bennett DA, Arnold SE, Ahima RS. Associations of Serum Insulin and Related Measures With Neuropathology and Cognition in Older Persons With and Without Diabetes. Ann Neurol 2024; 95:665-676. [PMID: 38379184 PMCID: PMC11023784 DOI: 10.1002/ana.26882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/23/2023] [Accepted: 01/26/2024] [Indexed: 02/22/2024]
Abstract
OBJECTIVE To examine associations of serum insulin and related measures with neuropathology and cognition in older persons. METHODS We studied 192 older persons (96 with diabetes and 96 without, matched by sex and balanced by age-at-death, education, and postmortem interval) from a community-based, clinical-pathologic study of aging, with annual evaluations including neuropsychological testing (summarized into global cognition and 5 cognitive domains) and postmortem autopsy. We assessed serum insulin, glucose, leptin, adiponectin, hemoglobin A1C, advanced glycation-end products (AGEs), and receptors for advanced glycation-end products, and calculated the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and adiponectin-to-leptin ratio. Using adjusted regression analyses, we examined the associations of serum measures with neuropathology of cerebrovascular disease and Alzheimer's disease, and with the level of cognition proximate-to-death. RESULTS Higher HOMA-IR was associated with the presence of brain infarcts and specifically microinfarcts, and higher HOMA-IR and leptin were each associated with subcortical infarcts. Further, higher leptin levels and lower adiponectin-to-leptin ratios were associated with the presence of moderate-to-severe atherosclerosis. Serum insulin and related measures were not associated with the level of Alzheimer's disease pathology, as assessed by global, as well as amyloid burden or tau tangle density scores. Regarding cognitive outcomes, higher insulin and leptin levels, and lower adiponectin and receptors for advanced glycation-end products levels, respectively, were each associated with lower levels of global cognition. INTERPRETATION Peripheral insulin resistance indicated by HOMA-IR and related serum measures was associated with a greater burden of cerebrovascular neuropathology and lower cognition. ANN NEUROL 2024;95:665-676.
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Affiliation(s)
- Zoe Arvanitakis
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL
| | - Ana W Capuano
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL
| | - Han Tong
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL
| | - Rupal I Mehta
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL
| | - Frederick Anokye-Danso
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL
| | - Steven E Arnold
- Alzheimer's Clinical and Translational Research Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Rexford S Ahima
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD
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Vandendriessche C, Kapogiannis D, Vandenbroucke RE. Biomarker and therapeutic potential of peripheral extracellular vesicles in Alzheimer's disease. Adv Drug Deliv Rev 2022; 190:114486. [PMID: 35952829 PMCID: PMC9985115 DOI: 10.1016/j.addr.2022.114486] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 07/01/2022] [Accepted: 08/03/2022] [Indexed: 01/24/2023]
Abstract
Extracellular vesicles (EVs) are cell-derived nanoparticles with an important role in intercellular communication, even across brain barriers. The bidirectional brain-barrier crossing capacity of EVs is supported by research identifying neuronal markers in peripheral EVs, as well as the brain delivery of peripherally administered EVs. In addition, EVs are reflective of their cellular origin, underlining their biomarker and therapeutic potential when released by diseased and regenerative cells, respectively. Both characteristics are of interest in Alzheimer's disease (AD) where the current biomarker profile is solely based on brain-centered readouts and effective therapeutic options are lacking. In this review, we elaborate on the role of peripheral EVs in AD. We focus on bulk EVs and specific EV subpopulations including bacterial EVs (bEVs) and neuronal-derived EVs (nEVs), which have mainly been studied from a biomarker perspective. Furthermore, we highlight the therapeutic potential of peripherally administered EVs whereby research has centered around stem cell derived EVs.
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Affiliation(s)
- Charysse Vandendriessche
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Dimitrios Kapogiannis
- Intramural Research Program, Laboratory of Clinical Investigation, National Institute on Aging, Baltimore, USA; Department of Neurology, Johns Hopkins School of Medicine, Baltimore, USA
| | - Roosmarijn E Vandenbroucke
- VIB Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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Rhea EM, Banks WA, Raber J. Insulin Resistance in Peripheral Tissues and the Brain: A Tale of Two Sites. Biomedicines 2022; 10:1582. [PMID: 35884888 PMCID: PMC9312939 DOI: 10.3390/biomedicines10071582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 12/12/2022] Open
Abstract
The concept of insulin resistance has been around since a few decades after the discovery of insulin itself. To allude to the classic Charles Dicken's novel published 62 years before the discovery of insulin, in some ways, this is the best of times, as the concept of insulin resistance has expanded to include the brain, with the realization that insulin has a life beyond the regulation of glucose. In other ways, it is the worst of times as insulin resistance is implicated in devastating diseases, including diabetes mellitus, obesity, and Alzheimer's disease (AD) that affect the brain. Peripheral insulin resistance affects nearly a quarter of the United States population in adults over age 20. More recently, it has been implicated in AD, with the degree of brain insulin resistance correlating with cognitive decline. This has led to the investigation of brain or central nervous system (CNS) insulin resistance and the question of the relation between CNS and peripheral insulin resistance. While both may involve dysregulated insulin signaling, the two conditions are not identical and not always interlinked. In this review, we compare and contrast the similarities and differences between peripheral and CNS insulin resistance. We also discuss how an apolipoprotein involved in insulin signaling and related to AD, apolipoprotein E (apoE), has distinct pools in the periphery and CNS and can indirectly affect each system. As these systems are both separated but also linked via the blood-brain barrier (BBB), we discuss the role of the BBB in mediating some of the connections between insulin resistance in the brain and in the peripheral tissues.
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Affiliation(s)
- Elizabeth M. Rhea
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA; (E.M.R.); (W.A.B.)
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - William A. Banks
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA; (E.M.R.); (W.A.B.)
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Jacob Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA
- Departments of Neurology and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR 97239, USA
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Gomes DE, Witwer KW. L1CAM-associated extracellular vesicles: A systematic review of nomenclature, sources, separation, and characterization. JOURNAL OF EXTRACELLULAR BIOLOGY 2022; 1:e35. [PMID: 35492832 PMCID: PMC9045013 DOI: 10.1002/jex2.35] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 02/19/2022] [Accepted: 02/24/2022] [Indexed: 12/20/2022]
Abstract
When released into biological fluids like blood or saliva, brain extracellular vesicles (EVs) might provide a window into otherwise inaccessible tissue, contributing useful biomarkers of neurodegenerative and other central nervous system (CNS) diseases. To enrich for brain EVs in the periphery, however, cell-specific EV surface markers are needed. The protein that has been used most frequently to obtain EVs of putative neuronal origin is the transmembrane L1 cell adhesion molecule (L1CAM/CD171). In this systematic review, we examine the existing literature on L1CAM and EVs, including investigations of both neurodegenerative disease and cancer through the lens of the minimal information for studies of EVs (MISEV), specifically in the domains of nomenclature usage, EV sources, and EV separation and characterization. Although numerous studies have reported L1CAM-associated biomarker signatures that correlate with disease, interpretation of these results is complicated since L1CAM expression is not restricted to neurons and is also upregulated during cancer progression. A recent study has suggested that L1CAM epitopes are present in biofluids mostly or entirely as cleaved, soluble protein. Our findings on practices and trends in L1CAM-mediated EV separation, enrichment, and characterization yield insights that may assist with interpreting results, evaluating rigor, and suggesting avenues for further exploration.
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Affiliation(s)
- Dimitria E. Gomes
- Cornell University College of Veterinary MedicineIthacaNew YorkUSA
- Department of Molecular and Comparative PathobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Kenneth W. Witwer
- Department of Molecular and Comparative PathobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
- The Richman Family Precision Medicine Centre of Excellence in Alzheimer's DiseaseJohns Hopkins University School of MedicineBaltimoreMarylandUSA
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Avgerinos KI, Mullins RJ, Egan JM, Kapogiannis D. Ketone Ester Effects on Biomarkers of Brain Metabolism and Cognitive Performance in Cognitively Intact Adults ≥ 55 Years Old. A Study Protocol for a Double-Blinded Randomized Controlled Clinical Trial. J Prev Alzheimers Dis 2022; 9:54-66. [PMID: 35098974 PMCID: PMC9359666 DOI: 10.14283/jpad.2022.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Ketone bodies have been proposed as an "energy rescue" for the Alzheimer's disease (AD) brain, which underutilizes glucose. Prior research has shown that oral ketone monoester (KME) safely induces robust ketosis in humans and has demonstrated cognitive-enhancing and pathology-reducing properties in animal models of AD. However, human evidence that KME may enhance brain ketone metabolism, improve cognitive performance and engage AD pathogenic cascades is scarce. OBJECTIVES To investigate the effects of ketone monoester (KME) on brain metabolism, cognitive performance and AD pathogenic cascades in cognitively normal older adults with metabolic syndrome and therefore at higher risk for AD. DESIGN Double-blinded randomized placebo-controlled clinical trial. SETTING Clinical Unit of the National Institute on Aging, Baltimore, US. PARTICIPANTS Fifty cognitively intact adults ≥ 55 years old, with metabolic syndrome. INTERVENTION Drinks containing 25 g of KME or isocaloric placebo consumed three times daily for 28 days. OUTCOMES Primary: concentration of beta-hydroxybutyrate (BHB) in precuneus measured with Magnetic Resonance Spectroscopy (MRS). Exploratory: plasma and urine BHB, multiple brain and muscle metabolites detected with MRS, cognition assessed with the PACC and NIH toolbox, biomarkers of AD and metabolic mediators in plasma extracellular vesicles, and stool microbiome. DISCUSSION This is the first study to investigate the AD-biomarker and cognitive effects of KME in humans. Ketone monoester is safe, tolerable, induces robust ketosis, and animal studies indicate that it can modify AD pathology. By conducting a study of KME in a population at risk for AD, we hope to bridge the existing gap between pre-clinical evidence and the potential for brain-metabolic, pro-cognitive, and anti-Alzheimer's effects in humans.
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Affiliation(s)
- K I Avgerinos
- Dimitrios Kapogiannis, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, 8C228, Baltimore, MD 21224, USA; Email address: ; Telephone: +1 410 350 3953
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Mitochondrial Electron Transport Chain Protein Abnormalities Detected in Plasma Extracellular Vesicles in Alzheimer's Disease. Biomedicines 2021; 9:biomedicines9111587. [PMID: 34829816 PMCID: PMC8615874 DOI: 10.3390/biomedicines9111587] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/12/2021] [Accepted: 10/27/2021] [Indexed: 12/18/2022] Open
Abstract
Mitochondria provide energy to neurons through oxidative phosphorylation and eliminate Reactive Oxygen Species (ROS) through Superoxide Dismutase 1 (SOD1). Dysfunctional mitochondria, manifesting decreased activity of electron transport chain (ETC) complexes and high ROS levels, are involved in Alzheimer’s disease (AD) pathogenesis. We hypothesized that neuronal mitochondrial dysfunction in AD is reflected in ETC and SOD1 levels and activity in plasma neuron-derived extracellular vesicles (NDEVs). We immunoprecipitated NDEVs targeting neuronal marker L1CAM from two cohorts: one including 22 individuals with early AD and 29 control subjects; and another including 14 individuals with early AD and 14 control subjects. In the first cohort, we measured levels of complexes I, III, IV, ATP synthase, and SOD1; in the second cohort, we measured levels and catalytic activity of complexes IV and ATP synthase. AD individuals had lower levels of complexes I (p < 0.0001), III (p < 0.0001), IV (p = 0.0061), and V (p < 0.0001), and SOD1 (p < 0.0001) compared to controls. AD individuals also had lower levels of catalytic activity of complex IV (p = 0.0214) and ATP synthase (p < 0.0001). NDEVs confirm quantitative and functional abnormalities in ECT complexes and SOD1 previously observed in AD models and during autopsy, opening the way for using them as biomarkers for mitochondrial dysfunction in AD.
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10
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Targeting Common Signaling Pathways for the Treatment of Stroke and Alzheimer's: a Comprehensive Review. Neurotox Res 2021; 39:1589-1612. [PMID: 34169405 DOI: 10.1007/s12640-021-00381-7] [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: 02/05/2021] [Revised: 04/11/2021] [Accepted: 05/24/2021] [Indexed: 12/30/2022]
Abstract
Neurodegenerative diseases such as stroke and Alzheimer's disease (AD) are two inter-related disorders that affect the neurons in the brain and central nervous system. Alzheimer's is a disease by undefined origin and causes. Stroke and its most common type, ischemic stroke (IS), occurs due to the blockade of cerebral blood vessels. As an important feature, both of disorders are associated with irreversible damages to the brain and nervous system. In this regard, finding common signaling pathways and the same molecular origin between these two diseases may be a promising way for their solution. On the basis of literature appraisal, the most common signaling cascades implicated in the pathogenesis of AD and stroke including notch, autophagy, inflammatory, and insulin signaling pathways were reviewed. Furthermore, current therapeutic strategies including natural and synthetic pharmaceuticals aiming modulation of respective signaling factors were scrutinized to ameliorate neural deficits in AD and stroke. Taken together, digging deeper in the common connections and signal targeting can be greatly helpful in understanding and unified treating of these disorders.
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11
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Exploring brain insulin resistance in adults with bipolar depression using extracellular vesicles of neuronal origin. J Psychiatr Res 2021; 133:82-92. [PMID: 33316649 PMCID: PMC7855678 DOI: 10.1016/j.jpsychires.2020.12.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/20/2020] [Accepted: 12/01/2020] [Indexed: 12/13/2022]
Abstract
Accumulating evidence suggests that disrupted insulin signaling is involved in bipolar disorder (BD) pathogenesis. Herein, we aimed to directly explore the potential role of neuronal insulin signaling using an innovative technique based on biomarkers derived from plasma extracellular vesicles enriched for neuronal origin (NEVs). We leveraged plasma samples from a randomized, double-blind, placebo-controlled, 12-week clinical trial evaluating infliximab as a treatment of bipolar depression. We isolated NEVs using immunoprecipitation against neuronal marker L1CAM from samples collected at baseline and weeks 2, 6 and 12 (endpoint) and measured NEV biomarkers using immunoassays. We assessed neuronal insulin signaling at its first node (IRS-1) and along the canonical (Akt, GSK-3β, p70S6K) and alternative (ERK1/2, JNK and p38-MAPK) pathways. A subset of participants (n = 27) also underwent whole-brain magnetic resonance imaging (MRI) at baseline and endpoint. Pre-treatment, NEV biomarkers of insulin signaling were independently associated with cognitive function and MRI measures (i.e. hippocampal and ventromedial prefrontal cortex [vmPFC] volumes). In fact, the association between IRS-1 phosphorylation at serine site 312 (pS312-IRS-1), an indicator of insulin resistance, and cognitive dysfunction was mediated by vmPFC volume. In the longitudinal analysis, patients treated with infliximab, a tumor necrosis factor-alpha antagonist with known insulin sensitizing properties, compared to those treated with placebo, had augmented phosphorylation of proteins from the alternative pathway. Infliximab responders had significant increases in phosphorylated JNK levels, relative to infliximab non-responders and placebo responders. In addition, treatment with infliximab resulted in increase in MRI measures of brain volume; treatment-related changes in the dorsolateral prefrontal cortex volume were mediated by changes in biomarkers from the insulin alternative pathway. In conclusion, our findings support the idea that brain insulin signaling is a target for further mechanistic and therapeutic investigations.
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