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Berthoud HR, Münzberg H, Morrison CD, Neuhuber WL. Hepatic interoception in health and disease. Auton Neurosci 2024; 253:103174. [PMID: 38579493 PMCID: PMC11129274 DOI: 10.1016/j.autneu.2024.103174] [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: 12/19/2023] [Revised: 03/14/2024] [Accepted: 03/28/2024] [Indexed: 04/07/2024]
Abstract
The liver is a large organ with crucial functions in metabolism and immune defense, as well as blood homeostasis and detoxification, and it is clearly in bidirectional communication with the brain and rest of the body via both neural and humoral pathways. A host of neural sensory mechanisms have been proposed, but in contrast to the gut-brain axis, details for both the exact site and molecular signaling steps of their peripheral transduction mechanisms are generally lacking. Similarly, knowledge about function-specific sensory and motor components of both vagal and spinal access pathways to the hepatic parenchyma is missing. Lack of progress largely owes to controversies regarding selectivity of vagal access pathways and extent of hepatocyte innervation. In contrast, there is considerable evidence for glucose sensors in the wall of the hepatic portal vein and their importance for glucose handling by the liver and the brain and the systemic response to hypoglycemia. As liver diseases are on the rise globally, and there are intriguing associations between liver diseases and mental illnesses, it will be important to further dissect and identify both neural and humoral pathways that mediate hepatocyte-specific signals to relevant brain areas. The question of whether and how sensations from the liver contribute to interoceptive self-awareness has not yet been explored.
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Affiliation(s)
- Hans-Rudolf Berthoud
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA.
| | - Heike Münzberg
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Christopher D Morrison
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Winfried L Neuhuber
- Institute for Anatomy and Cell Biology, Friedrich-Alexander University, Erlangen, Germany.
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Freitas SCF, Harthmann ÂD, Rodrigues B, Irigoyen MC, De Angelis K. Effect of aerobic exercise training on regional blood flow and vascular resistance in diabetic rats. Diabetol Metab Syndr 2015; 7:115. [PMID: 26697119 PMCID: PMC4687277 DOI: 10.1186/s13098-015-0109-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 12/01/2015] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Hyperglycemia has been associated with decreased blood flow in various organs, leading to tissue damage and dysfunctions. Exercise training (ET) is known to promote beneficial changes in the autonomic nervous system and may have effects on circulation. The aim of this study was to evaluate coronary and renal blood flows and vascular resistances after ET in diabetic rats. METHODS Thirty-two rats were divided into four groups (n = 8): sedentary control (SC), trained control (TC), sedentary diabetic (SD), trained diabetic (TD). Diabetes was induced by an injection of streptozotocin (STZ, 50 mg/kg). The ET was performed on a treadmill for 10 weeks. The blood flows were measured using colored microspheres. RESULTS The diabetic groups presented hyperglycemia (blood glucose >350 mg/dL) and ET did not change this parameter. The SD group showed reduced renal blood flow when compared to SC group, and ET was able to normalize this parameter in TD rats (SC: 4.3 ± 0.5; TC: 2.9 ± 0.3; SD: 1.9 ± 0.4; TD: 3.2 ± 0.4 mL/min/g). TD group presented increased coronary blood flow in relation to SD group (SC: 2.3 ± 0.23; TC: 2.8 ± 0.5; SD: 1.2 ± 0.4; TD: 3.0 ± 0.4 mL/min/g). The heart and kidneys vascular resistance were increased in SD group when compared to SC group, and ET was able to reverse these changes. CONCLUSIONS Given the relevance of cardiomyopathy and nephropathy in mortality of diabetics, our results demonstrated that ET is effective in improving coronary and renal blood flows and vascular resistances in STZ-diabetic rats, reinforcing the positive role of this approach in preventing hyperglycemia-induced long-term organ damage.
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Affiliation(s)
- Sarah Cristina Ferreira Freitas
- />Translational Physiology Laboratory, Universidade Nove de Julho, Rua Vergueiro 235/249, 2º subsolo, São Paulo, SP 01504 001 Brazil
| | - Ângela d’Avila Harthmann
- />Hypertension Unit, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Bruno Rodrigues
- />Departament of Adapted Physical Education, Faculty of Physical Education (FEF), University of Campinas (UNICAMP), Campinas, SP Brazil
| | - Maria-Cláudia Irigoyen
- />Hypertension Unit, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Kátia De Angelis
- />Translational Physiology Laboratory, Universidade Nove de Julho, Rua Vergueiro 235/249, 2º subsolo, São Paulo, SP 01504 001 Brazil
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Effects of physical activity upon the liver. Eur J Appl Physiol 2014; 115:1-46. [DOI: 10.1007/s00421-014-3031-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 10/14/2014] [Indexed: 02/07/2023]
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Exercise intensity modulation of hepatic lipid metabolism. J Nutr Metab 2012; 2012:809576. [PMID: 22545209 PMCID: PMC3321535 DOI: 10.1155/2012/809576] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2011] [Accepted: 01/11/2012] [Indexed: 12/12/2022] Open
Abstract
Lipid metabolism in the liver is complex and involves the synthesis and secretion of very low density lipoproteins (VLDL), ketone bodies, and high rates of fatty acid oxidation, synthesis, and esterification. Exercise training induces several changes in lipid metabolism in the liver and affects VLDL secretion and fatty acid oxidation. These alterations are even more conspicuous in disease, as in obesity, and cancer cachexia. Our understanding of the mechanisms leading to metabolic adaptations in the liver as induced by exercise training has advanced considerably in the recent years, but much remains to be addressed. More recently, the adoption of high intensity exercise training has been put forward as a means of modulating hepatic metabolism. The purpose of the present paper is to summarise and discuss the merit of such new knowledge.
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Nindl BC, Alemany JA, Tuckow AP, Rarick KR, Staab JS, Kraemer WJ, Maresh CM, Spiering BA, Hatfield DL, Flyvbjerg A, Frystyk J. Circulating bioactive and immunoreactive IGF-I remain stable in women, despite physical fitness improvements after 8 weeks of resistance, aerobic, and combined exercise training. J Appl Physiol (1985) 2010; 109:112-20. [DOI: 10.1152/japplphysiol.00025.2010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Insulin-like growth factor-I (IGF-I) is regulated by a number of IGF-binding proteins (IGFBPs) and proteases that influence IGF-I bioactivity. A specific IGF-I kinase receptor activation assay (KIRA) has been developed that determines the ability of IGF-I to activate the IGF-I receptor by quantification of intracellular receptor autophosphorylation on IGF-I binding. KIRA-assessed IGF-I bioactivity has not been utilized within the context of chronic exercise training paradigms. This study measured total and free immunoreactive IGF-I, bioactive IGF-I, and IGFBP-1, -2, and -3 before (Pre), during (Mid), and after (Post) 8 wk of exercise training in young, healthy women, who were randomized into one of four groups: control ( n = 10), resistance ( n = 18), aerobic ( n = 13), and combined ( n = 15) exercise training. The training programs were effective in improving physical fitness specific to the exercise mode engaged in: increases were observed for lean mass (∼2%), aerobic fitness (6–7%), and upper (20–24%) and lower (15–48%) body strength (all P values < 0.05). By contrast, no time, group, or interaction effects were observed for the circulating IGF-I system, as immunoreactive total (Pre = 264 ± 16 μg/l; Mid = 268 ± 17 μg/l; Post = 271 ± 17 μg/l), free (Pre = 0.70 ± 0.1 μg/l; Mid = 0.63 ± 0.1 μg/l; Post = 0.63 ± 0.2 μg/l) and bioactive (Pre = 2.35 ± 0.3 μg/l; Mid = 2.25 ± 0.3 μg/l; Post = 2.33 ± 0.3 μg/l) IGF-I were unchanged throughout the study. All IGFBP measures were also unchanged. We conclude that increased lean mass, aerobic fitness, and upper and lower body strength resulting from an 8-wk exercise training programs can occur without concomitant increases in either circulating bioactive or immunoreactive IGF-I, as well as associated IGFBPs. In terms of reflecting positive anabolic neuromuscular outcomes, these data do not support a role for endocrine-derived IGF-I.
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Affiliation(s)
- Bradley C. Nindl
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Joseph A. Alemany
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Alexander P. Tuckow
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Kevin R. Rarick
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Jeffery S. Staab
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - William J. Kraemer
- Human Performance Laboratory, University of Connecticut, Storrs, Connecticut; and
| | - Carl M. Maresh
- Human Performance Laboratory, University of Connecticut, Storrs, Connecticut; and
| | - Barry A. Spiering
- Human Performance Laboratory, University of Connecticut, Storrs, Connecticut; and
| | - Disa L. Hatfield
- Human Performance Laboratory, University of Connecticut, Storrs, Connecticut; and
| | - Allan Flyvbjerg
- Medical Research Laboratories, Clinical Institute of Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Jan Frystyk
- Medical Research Laboratories, Clinical Institute of Medicine, Aarhus University Hospital, Aarhus, Denmark
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van Baak MA. Meal-induced activation of the sympathetic nervous system and its cardiovascular and thermogenic effects in man. Physiol Behav 2008; 94:178-86. [DOI: 10.1016/j.physbeh.2007.12.020] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 12/20/2007] [Accepted: 12/21/2007] [Indexed: 12/01/2022]
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Cunha TS, Tanno AP, Costa Sampaio Moura MJ, Marcondes FK. Influence of high-intensity exercise training and anabolic androgenic steroid treatment on rat tissue glycogen content. Life Sci 2005; 77:1030-43. [PMID: 15904936 DOI: 10.1016/j.lfs.2005.03.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2004] [Accepted: 03/04/2005] [Indexed: 10/25/2022]
Abstract
To increase tissue glycogen content many athletes use anabolic androgenic steroids (AAS). However, the literature concerning the effects of androgens on glycogen metabolism is conflicting. This study aimed to determine the influence of training and AAS on body weight (bw), triglycerides, glucose, tissue glycogen and transaminases levels. Male Wistar rats, randomized into four groups (sedentary vehicle (SV), sedentary AAS (SA), trained vehicle (TV) and trained AAS (TA)), were treated with nadrolone (5 mg/Kg, 2x/week, i.m.) or vehicle. Trained rats performed jumps into water (4 sets, 10 repetitions, 30 sec rest) carrying a 50-70% body wt-load strapped to the chest (5 days/week,6 weeks). Two days after the last session, the animals were killed (bifatorial ANOVA+Tukey test; P < 0.05). Trained animals presented lower bw (TV:345+/-7 vs. SV:380+/-7 and TA:328+/-4 vs SA:370+/-11 g) and triglycerides levels (TV:77+/-3 vs. SV:98+/-4 and TA:79+/-3 vs. SA:98+/-8 mg/dL) and higher glycogen content in liver (TV:5.3+/-0.2 vs. SV:3.9+/-0.1 and TA:5.3+/-0.3 vs. SA:4.6+/-0,2 mg/100 mg) and in gastrocnemious (TV:0.70+/-0.02 vs. SV:0.49+/-0.01 and TA:0.73+/-0.03 vs. SA:0.57+/-0.02 mg/100 mg) than sedentary ones. In the cardiac muscle, the association between training and AAS increased glycogen content (TA:0.19+/-0.01 > SV:0.13+/-0.01=TV:0.13+/-0.01=SA:0.14+/-0.01 mg/100 mg). In the soleus AAS increased glycogen (SA:0.53+/-0.03 vs. SV:0.43+/-0.01 and TA:0.58+/-0.02 vs. TV:0.48+/-0.01 mg/100 mg). Exercise training and AAS had no effect on blood glucose and transaminases levels. Training and AAS effects on glycogen supercompensation are tissue-dependent and the effects of association between them were only observed in the cardiac muscle. These data emphasize the necessity of more studies to confirm greater effects of AAS than those promoted by physical exercise.
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Affiliation(s)
- Tatiana Sousa Cunha
- Department of Physiological Sciences, Faculty of Dentistry of Piracicaba, State University of Campinas, Piracicaba, SP, Brazil
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Kreier F, Kalsbeek A, Ruiter M, Yilmaz A, Romijn JA, Sauerwein HP, Fliers E, Buijs RM. Central nervous determination of food storage—a daily switch from conservation to expenditure: implications for the metabolic syndrome. Eur J Pharmacol 2003; 480:51-65. [PMID: 14623350 DOI: 10.1016/j.ejphar.2003.08.092] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Here, we present a neuroendocrine concept to review the circularly interacting energy homeostasis system between brain and body. Body-brain interaction is circular because the brain immediately integrates an input to an output, and because part of this response may be that the brain modulates the sensitivity of this perception. First, we describe how the brain senses the body through neurons and blood-borne factors. Direct neuronal connections report the state of various organs. In addition, humoral factors are perceived by the blood-brain barrier and circumventricular organs. We describe how circulating energy carriers are sensed and what signals reach the brain during food intake, exercise and an immune response. We describe that the brain regulates the homeostatic process at two fundamentally different levels during the active and inactive states. The unbalanced output of the brain in the metabolic syndrome is discussed in relation with such circadian rhythms and with regional activity of the autonomic nervous system. In line with the above, we suggest a new approach for the diagnosis and therapy of the metabolic syndrome.
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Affiliation(s)
- Felix Kreier
- Netherlands Institute for Brain Research, 1105 AZ, Amsterdam, The Netherlands.
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