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Heni M. The insulin resistant brain: impact on whole-body metabolism and body fat distribution. Diabetologia 2024; 67:1181-1191. [PMID: 38363340 PMCID: PMC11153284 DOI: 10.1007/s00125-024-06104-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 12/19/2023] [Indexed: 02/17/2024]
Abstract
Insulin exerts its actions not only on peripheral organs but is also transported into the brain where it performs distinct functions in various brain regions. This review highlights recent advancements in our understanding of insulin's actions within the brain, with a specific emphasis on investigations in humans. It summarises current knowledge on the transport of insulin into the brain. Subsequently, it showcases robust evidence demonstrating the existence and physiological consequences of brain insulin action, while also introducing the presence of brain insulin resistance in humans. This pathophysiological condition goes along with an impaired acute modulation of peripheral metabolism in response to brain insulin action, particularly in the postprandial state. Furthermore, brain insulin resistance has been associated with long-term adiposity and an unfavourable adipose tissue distribution, thus implicating it in the pathogenesis of subgroups of obesity and (pre)diabetes that are characterised by distinct patterns of body fat distribution. Encouragingly, emerging evidence suggests that brain insulin resistance could represent a treatable entity, thereby opening up novel therapeutic avenues to improve systemic metabolism and enhance brain functions, including cognition. The review closes with an outlook towards prospective research directions aimed at further elucidating the clinical implications of brain insulin resistance. It emphasises the critical need to establish feasible diagnostic measures and effective therapeutic interventions.
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Affiliation(s)
- Martin Heni
- Division of Endocrinology and Diabetology, Department of Internal Medicine 1, University Hospital Ulm, Ulm, Germany.
- Department for Diagnostic Laboratory Medicine, Institute for Clinical Chemistry and Pathobiochemistry, University Hospital of Tübingen, Tübingen, Germany.
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2
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Wong CYJ, Baldelli A, Hoyos CM, Tietz O, Ong HX, Traini D. Insulin Delivery to the Brain via the Nasal Route: Unraveling the Potential for Alzheimer's Disease Therapy. Drug Deliv Transl Res 2024; 14:1776-1793. [PMID: 38441832 PMCID: PMC11153287 DOI: 10.1007/s13346-024-01558-1] [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] [Accepted: 02/19/2024] [Indexed: 06/06/2024]
Abstract
This comprehensive review delves into the potential of intranasal insulin delivery for managing Alzheimer's Disease (AD) while exploring the connection between AD and diabetes mellitus (DM). Both conditions share features of insulin signalling dysregulation and oxidative stress that accelerate inflammatory response. Given the physiological barriers to brain drug delivery, including the blood-brain barrier, intranasal administration emerges as a non-invasive alternative. Notably, intranasal insulin has shown neuroprotective effects, impacting Aβ clearance, tau phosphorylation, and synaptic plasticity. In preclinical studies and clinical trials, intranasally administered insulin achieved rapid and extensive distribution throughout the brain, with optimal formulations exhibiting minimal systemic circulation. The detailed mechanism of insulin transport through the nose-to-brain pathway is elucidated in the review, emphasizing the role of olfactory and trigeminal nerves. Despite promising prospects, challenges in delivering protein drugs from the nasal cavity to the brain remain, including enzymes, tight junctions, mucociliary clearance, and precise drug deposition, which hinder its translation to clinical settings. The review encompasses a discussion of the strategies to enhance the intranasal delivery of therapeutic proteins, such as tight junction modulators, cell-penetrating peptides, and nano-drug carrier systems. Moreover, successful translation of nose-to-brain drug delivery necessitates a holistic understanding of drug transport mechanisms, brain anatomy, and nasal formulation optimization. To date, no intranasal insulin formulation has received regulatory approval for AD treatment. Future research should address challenges related to drug absorption, nasal deposition, and the long-term effects of intranasal insulin. In this context, the evaluation of administration devices for nose-to-brain drug delivery becomes crucial in ensuring precise drug deposition patterns and enhancing bioavailability.
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Affiliation(s)
- Chun Yuen Jerry Wong
- Respiratory Technology, Woolcock Institute of Medical Research, Sydney, NSW, 2037, Australia
- Faculty of Medicine and Health Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW, 2109, Australia
| | - Alberto Baldelli
- Faculty of Land and Food Systems, The University of British Columbia, 2357 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Camilla M Hoyos
- Faculty of Medicine and Health Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW, 2109, Australia
- CIRUS Centre for Sleep and Chronobiology, Woolcock Institute of Medical Research, Sydney, NSW, 2037, Australia
| | - Ole Tietz
- Dementia Research Centre, Faculty of Medicine and Health Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW, 2109, Australia
| | - Hui Xin Ong
- Respiratory Technology, Woolcock Institute of Medical Research, Sydney, NSW, 2037, Australia.
- Faculty of Medicine and Health Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW, 2109, Australia.
| | - Daniela Traini
- Respiratory Technology, Woolcock Institute of Medical Research, Sydney, NSW, 2037, Australia.
- Faculty of Medicine and Health Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW, 2109, Australia.
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Becerra LA, Gavrieli A, Khan F, Novak P, Lioutas V, Ngo LH, Novak V, Mantzoros CS. Daily intranasal insulin at 40IU does not affect food intake and body composition: A placebo-controlled trial in older adults over a 24-week period with 24-weeks of follow-up. Clin Nutr 2023; 42:825-834. [PMID: 37084469 PMCID: PMC10330069 DOI: 10.1016/j.clnu.2023.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/27/2023] [Accepted: 04/07/2023] [Indexed: 04/23/2023]
Abstract
Centrally administered insulin stimulates the reward system to reduce appetite in response to food intake in animal studies. In humans, studies have shown conflicting results, with some studies suggesting that intranasal insulin (INI) in relatively high doses may decrease appetite, body fat, and weight in various populations. These hypotheses have not been tested in a large longitudinal placebo-controlled study. Participants in the Memory Advancement with Intranasal Insulin in Type 2 Diabetes (MemAID) trial were enrolled in this study. This study on energy homeostasis enrolled 89 participants who completed baseline and at least 1 intervention visit (42 women; age 65 ± 9 years; 46 INI, 38 with type 2 diabetes) and 76 completed treatment (16 women, age 64 ± 9; 38 INI, 34 with type 2 diabetes). The primary outcome was the INI effect on food intake. Secondary outcomes included the effect of INI on appetite and anthropometric measures, including body weight and body composition. In exploratory analyses, we tested the interaction of treatment with gender, body mass index (BMI), and diagnosis of type 2 diabetes. There was no INI effect on food intake or any of the secondary outcomes. INI also showed no differential effect on primary and secondary outcomes when considering gender, BMI, and type 2 diabetes. INI did not alter appetite or hunger nor cause weight loss when used at 40 I.U. intranasally daily for 24 weeks in older adults with and without type 2 diabetes.
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Affiliation(s)
- Laura Aponte Becerra
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Anna Gavrieli
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Faizan Khan
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Peter Novak
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Vasileios Lioutas
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Long H Ngo
- Department of Medicine, Beth Israel Deaconess Medical Center and School of Public Health, Harvard Medical School, Boston, MA, USA
| | - Vera Novak
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Christos S Mantzoros
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Medicine, Boston VA Healthcare System, Boston, MA, USA.
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Stahel P, Xiao C, Nahmias A, Tian L, Lewis GF. Multi-organ Coordination of Lipoprotein Secretion by Hormones, Nutrients and Neural Networks. Endocr Rev 2021; 42:815-838. [PMID: 33743013 PMCID: PMC8599201 DOI: 10.1210/endrev/bnab008] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 12/15/2022]
Abstract
Plasma triglyceride-rich lipoproteins (TRL), particularly atherogenic remnant lipoproteins, contribute to atherosclerotic cardiovascular disease. Hypertriglyceridemia may arise in part from hypersecretion of TRLs by the liver and intestine. Here we focus on the complex network of hormonal, nutritional, and neuronal interorgan communication that regulates secretion of TRLs and provide our perspective on the relative importance of these factors. Hormones and peptides originating from the pancreas (insulin, glucagon), gut [glucagon-like peptide 1 (GLP-1) and 2 (GLP-2), ghrelin, cholecystokinin (CCK), peptide YY], adipose tissue (leptin, adiponectin) and brain (GLP-1) modulate TRL secretion by receptor-mediated responses and indirectly via neural networks. In addition, the gut microbiome and bile acids influence lipoprotein secretion in humans and animal models. Several nutritional factors modulate hepatic lipoprotein secretion through effects on the central nervous system. Vagal afferent signaling from the gut to the brain and efferent signals from the brain to the liver and gut are modulated by hormonal and nutritional factors to influence TRL secretion. Some of these factors have been extensively studied and shown to have robust regulatory effects whereas others are "emerging" regulators, whose significance remains to be determined. The quantitative importance of these factors relative to one another and relative to the key regulatory role of lipid availability remains largely unknown. Our understanding of the complex interorgan regulation of TRL secretion is rapidly evolving to appreciate the extensive hormonal, nutritional, and neural signals emanating not only from gut and liver but also from the brain, pancreas, and adipose tissue.
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Affiliation(s)
- Priska Stahel
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Avital Nahmias
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Lili Tian
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Gary Franklin Lewis
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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Scherer T, Sakamoto K, Buettner C. Brain insulin signalling in metabolic homeostasis and disease. Nat Rev Endocrinol 2021; 17:468-483. [PMID: 34108679 DOI: 10.1038/s41574-021-00498-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/22/2021] [Indexed: 02/06/2023]
Abstract
Insulin signalling in the central nervous system regulates energy homeostasis by controlling metabolism in several organs and by coordinating organ crosstalk. Studies performed in rodents, non-human primates and humans over more than five decades using intracerebroventricular, direct hypothalamic or intranasal application of insulin provide evidence that brain insulin action might reduce food intake and, more importantly, regulates energy homeostasis by orchestrating nutrient partitioning. This Review discusses the metabolic pathways that are under the control of brain insulin action and explains how brain insulin resistance contributes to metabolic disease in obesity, the metabolic syndrome and type 2 diabetes mellitus.
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Affiliation(s)
- Thomas Scherer
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
| | - Kenichi Sakamoto
- Division of Endocrinology, Metabolism & Nutrition, Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Christoph Buettner
- Division of Endocrinology, Metabolism & Nutrition, Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
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Tashima T. Shortcut Approaches to Substance Delivery into the Brain Based on Intranasal Administration Using Nanodelivery Strategies for Insulin. Molecules 2020; 25:E5188. [PMID: 33171799 PMCID: PMC7664636 DOI: 10.3390/molecules25215188] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 10/26/2020] [Accepted: 11/05/2020] [Indexed: 12/13/2022] Open
Abstract
The direct delivery of central nervous system (CNS) drugs into the brain after administration is an ideal concept due to its effectiveness and non-toxicity. However, the blood-brain barrier (BBB) prevents drugs from penetrating the capillary endothelial cells, blocking their entry into the brain. Thus, alternative approaches must be developed. The nasal cavity directly leads from the olfactory epithelium to the brain through the cribriform plate of the skull bone. Nose-to-brain drug delivery could solve the BBB-related repulsion problem. Recently, it has been revealed that insulin improved Alzheimer's disease (AD)-related dementia. Several ongoing AD clinical trials investigate the use of intranasal insulin delivery. Related to the real trajectory, intranasal labeled-insulins demonstrated distribution into the brain not only along the olfactory nerve but also the trigeminal nerve. Nonetheless, intranasally administered insulin was delivered into the brain. Therefore, insulin conjugates with covalent or non-covalent cargos, such as AD or other CNS drugs, could potentially contribute to a promising strategy to cure CNS-related diseases. In this review, I will introduce the CNS drug delivery approach into the brain using nanodelivery strategies for insulin through transcellular routes based on receptor-mediated transcytosis or through paracellular routes based on escaping the tight junction at the olfactory epithelium.
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Affiliation(s)
- Toshihiko Tashima
- Tashima Laboratories of Arts and Sciences, 1239-5 Toriyama-cho, Kohoku-ku, Yokohama, Kanagawa 222-0035, Japan
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Ruiz HH, Díez RL, Arivazahagan L, Ramasamy R, Schmidt AM. Metabolism, Obesity, and Diabetes Mellitus. Arterioscler Thromb Vasc Biol 2019; 39:e166-e174. [PMID: 31242034 PMCID: PMC6693645 DOI: 10.1161/atvbaha.119.312005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Obesity and diabetes remain leading causes of reduced health span and life span throughout the world. Hence, it is not surprising that these areas are at the center of highly active areas of research. The identification of novel mechanisms underlying these metabolic disorders sets the stage for uncovering new potential therapeutic strategies. In this issue of Highlights in Arteriosclerosis, Thrombosis and Vascular Biology, we review recently published papers in the journal that add to our understanding of causes and consequences of obesity and diabetes and how these disorders impact metabolic function. Collectively, these studies in cultured cells to in vivo animal models to human subjects add to the growing body of evidence that both cell-intrinsic and cell-cell communication mechanisms collaborate in metabolic disorders to cause obesity, insulin resistance and diabetes and its complications.
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Affiliation(s)
- Henry H. Ruiz
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, N.Y. 10016
| | - Raquel López Díez
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, N.Y. 10016
| | - Lakshmi Arivazahagan
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, N.Y. 10016
| | - Ravichandran Ramasamy
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, N.Y. 10016
| | - Ann Marie Schmidt
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, N.Y. 10016
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Affiliation(s)
- Ann Marie Schmidt
- From the Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine.
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9
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Affiliation(s)
- Jacqueline S Dron
- From the Department of Biochemistry (J.S.D., J.L., R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Robarts Research Institute (J.S.D., J.L., R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Julieta Lazarte
- From the Department of Biochemistry (J.S.D., J.L., R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Robarts Research Institute (J.S.D., J.L., R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Medicine (J.L., R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Robert A Hegele
- From the Department of Biochemistry (J.S.D., J.L., R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Robarts Research Institute (J.S.D., J.L., R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Medicine (J.L., R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
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10
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Xiao C, Dash S, Stahel P, Lewis GF. Effects of intranasal insulin on endogenous glucose production in insulin-resistant men. Diabetes Obes Metab 2018. [PMID: 29536605 DOI: 10.1111/dom.13289] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The effects of intranasal insulin on the regulation of endogenous glucose production (EGP) in individuals with insulin resistance were assessed in a single-blind, crossover study. Overweight or obese insulin-resistant men (n = 7; body mass index 35.4 ± 4.4 kg/m2 , homeostatic model assessment of insulin resistance 5.6 ± 1.6) received intranasal spray of either 40 IU insulin lispro or placebo in 2 randomized visits. Acute systemic spillover of intranasal insulin into the circulation was matched with a 30-minute intravenous infusion of insulin lispro in the nasal placebo arm. EGP was assessed under conditions of a pancreatic clamp with a primed, constant infusion of glucose tracer. Under these experimental conditions, compared with placebo, intranasal administration of insulin did not significantly affect plasma glucose concentrations, EGP or glucose disposal in overweight/obese, insulin-resistant men, in contrast to our previous study, in which an equivalent dose of intranasal insulin significantly suppressed EGP in lean, insulin-sensitive men. Insulin resistance is probably associated with impairment in centrally mediated insulin suppression of EGP.
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Affiliation(s)
- Changting Xiao
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Satya Dash
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Priska Stahel
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Gary F Lewis
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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Xiao C, Stahel P, Carreiro AL, Buhman KK, Lewis GF. Recent Advances in Triacylglycerol Mobilization by the Gut. Trends Endocrinol Metab 2018; 29:151-163. [PMID: 29306629 DOI: 10.1016/j.tem.2017.12.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/26/2022]
Abstract
Dietary lipid absorption and lipoprotein secretion by the gut are important in maintaining whole-body energy homeostasis and have significant implications for health and disease. The processing of dietary lipids, including storage within and subsequent mobilization and transport from enterocyte cytoplasmic lipid droplets or other intestinal lipid storage pools (including the secretary pathway, lamina propria and lymphatics) and secretion of chylomicrons, involves coordinated steps that are subject to various controls. This review summarizes recent advances in our understanding of the mechanisms that underlie lipid storage and mobilization by small intestinal enterocytes and the intestinal lymphatic vasculature. Therapeutic targeting of lipid processing by the gut may provide opportunities for the treatment and prevention of dyslipidemia, and for improving health status.
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Affiliation(s)
- Changting Xiao
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Priska Stahel
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Alicia L Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Gary F Lewis
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada.
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