1
|
Cook TM, Bethea MM, Sandoval DA. The role of the gut-brain axis in bariatric surgery. Curr Opin Neurobiol 2025; 92:103041. [PMID: 40349608 DOI: 10.1016/j.conb.2025.103041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2024] [Revised: 04/04/2025] [Accepted: 04/13/2025] [Indexed: 05/14/2025]
Abstract
Bariatric surgery is the gold standard for sustained weight loss. Despite common misconceptions, bariatric surgery remodels gut-brain physiology in more complex ways than simply reducing stomach size or causing nutrient malabsorption. Bariatric surgery induces weight loss primarily by reductions in food intake and alterations in feeding patterns, macronutrient preference, and the rewarding aspects of food. Bariatric surgery also enhances nutrient-induced brain activation, alters nutrient processing, enhances gut hormone secretion, and increases bile acids. However, which of these signals directly link to improved satiety and altered reward pathways remains unclear. While state-of-the-art tools are now available to manipulate specific subpopulations of peripheral sensory neurons, work is needed to apply these tools to obesity and bariatric surgery. This will be critical for advancing the understanding of the role of the gut-brain axis in the success of surgery and allowing for the continued expansion of therapeutic options for obesity.
Collapse
Affiliation(s)
- Tyler M Cook
- Department of Pediatrics, Section of Nutrition, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Maigen M Bethea
- Department of Pediatrics, Section of Nutrition, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Darleen A Sandoval
- Department of Pediatrics, Section of Nutrition, University of Colorado Anschutz Medical Campus, Denver, CO, USA.
| |
Collapse
|
2
|
McKnight AD, Alhadeff AL. Nutrient detection pathways for food reinforcement and satiation. Curr Opin Neurobiol 2025; 92:103040. [PMID: 40349609 DOI: 10.1016/j.conb.2025.103040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2025] [Revised: 04/08/2025] [Accepted: 04/13/2025] [Indexed: 05/14/2025]
Abstract
Ingested food is broken down into macronutrient components that are detected by gut-brain signaling pathways that play a vital role in feeding behavior. These specialized mechanisms both promote food intake (via appetition and food reinforcement pathways) and terminate food intake (via satiation pathways). Despite recent significant advances in our understanding of gut-brain signaling and behavior, questions remain about the distinct mechanisms mediating food reinforcement and satiation. Here, we review the receptors/transporters and gut-brain pathways that contribute to nutrient sensing and feeding behavior, and highlight key knowledge gaps that will guide future research on the complex gut-brain systems that influence food intake.
Collapse
Affiliation(s)
- Aaron D McKnight
- Monell Chemical Senses Center, Philadelphia, 19104, PA, United States; Department of Neuroscience, University of Pennsylvania, Philadelphia, 19104, PA, United States
| | - Amber L Alhadeff
- Monell Chemical Senses Center, Philadelphia, 19104, PA, United States; Department of Neuroscience, University of Pennsylvania, Philadelphia, 19104, PA, United States.
| |
Collapse
|
3
|
Lin J, Shen Y, Xia Y, Li Y, Jiang T, Shen X, Fu Y, Zhang D, Yang L, Xu H, Xu Z, Wang L. Vagotomy suppresses food intake by increasing GLP-1 secretion via the M3 AChR-AMPKα pathway in mice. Mol Cell Endocrinol 2025; 599:112464. [PMID: 39848433 DOI: 10.1016/j.mce.2025.112464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2024] [Revised: 01/15/2025] [Accepted: 01/17/2025] [Indexed: 01/25/2025]
Abstract
OBJECTIVE The gut-brain axis (GBA) is involved in the modulation of multiple physiological activities, and the vagus nerve plays an important role in this process. However, the association between vagus nerve function and nutritional regulation remains unclear. Here, we explored changes in the nutritional status of mice after vagotomy and investigated the underlying mechanisms responsible for these changes. METHODS We performed vagotomies in mice and verified nerve resection using immunofluorescence staining. We then observed the food intake and body weight of the mice and tested nutritional and inflammation-related markers using enzyme-linked immunosorbent assay (ELISA) kits. The role of glucagon-like peptide 1 (GLP-1) in the GBA was determined using qRT-PCR and ELISA kits. Western blot and ELISA kits were used to explore the underlying mechanisms. RESULTS After vagotomy, the mice experienced a deterioration in their nutritional status, which manifested as a significant reduction in body weight and food intake. The expression of the proglucagon gene (GCG), which encodes GLP-1, significantly increased after vagotomy. Mechanistically, acetylcholine (ACh) reversed the HG (high glucose) -induced elevation of GLP-1 secretion. ACh upregulated AMPKα phosphorylation, thereby reducing GLP-1 secretion. Moreover, the level of AMPKα phosphorylation was enhanced by ACh via M3AChR. CONCLUSIONS ACh released by the vagus nerve counteracts the anorectic effects of GLP-1 under normal physiological conditions. Vagotomy blocks this feedback, resulting in a loss of food intake and body weight in mice.
Collapse
Affiliation(s)
- Jie Lin
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Yikai Shen
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Yiwen Xia
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Ying Li
- Hepatobiliary Surgery, Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Tianlu Jiang
- Department of General Surgery, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi Peolple's Hospital, Wuxi, Jiangsu Province, China
| | - Xusheng Shen
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Yiwang Fu
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Diancai Zhang
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Li Yang
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Hao Xu
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Zekuan Xu
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, Jiangsu Province, China.
| | - Linjun Wang
- Gastric Cancer Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China.
| |
Collapse
|
4
|
Hankir MK, Lutz TA. Novel neural pathways targeted by GLP-1R agonists and bariatric surgery. Pflugers Arch 2025; 477:171-185. [PMID: 39644359 PMCID: PMC11761532 DOI: 10.1007/s00424-024-03047-3] [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] [Received: 10/17/2024] [Revised: 11/18/2024] [Accepted: 11/19/2024] [Indexed: 12/09/2024]
Abstract
The glucagon-like peptide 1 receptor (GLP-1R) agonist semaglutide has revolutionized the treatment of obesity, with other gut hormone-based drugs lined up that show even greater weight-lowering ability in obese patients. Nevertheless, bariatric surgery remains the mainstay treatment for severe obesity and achieves unparalleled weight loss that generally stands the test of time. While their underlying mechanisms of action remain incompletely understood, it is clear that the common denominator between GLP-1R agonists and bariatric surgery is that they suppress food intake by targeting the brain. In this Review, we highlight recent preclinical studies using contemporary neuroscientific techniques that provide novel concepts in the neural control of food intake and body weight with reference to endogenous GLP-1, GLP-1R agonists, and bariatric surgery. We start in the periphery with vagal, intestinofugal, and spinal sensory nerves and then progress through the brainstem up to the hypothalamus and finish at non-canonical brain feeding centers such as the zona incerta and lateral septum. Further defining the commonalities and differences between GLP-1R agonists and bariatric surgery in terms of how they target the brain may not only help bridge the gap between pharmacological and surgical interventions for weight loss but also provide a neural basis for their combined use when each individually fails.
Collapse
Affiliation(s)
- Mohammed K Hankir
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
| |
Collapse
|
5
|
Hankir MK, Le Foll C. Central nervous system pathways targeted by amylin in the regulation of food intake. Biochimie 2025; 229:95-104. [PMID: 39426704 DOI: 10.1016/j.biochi.2024.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Revised: 10/04/2024] [Accepted: 10/17/2024] [Indexed: 10/21/2024]
Abstract
Amylin is a peptide hormone co-released with insulin from pancreatic β-cells during a meal and primarily serves to promote satiation. While the caudal hindbrain was originally implicated as a major site of action in this regard, it is becoming increasingly clear that amylin recruits numerous central nervous system pathways to exert multifaceted effects on food intake. In this Review, we discuss the evidence derived from preclinical studies showing that amylin and the related peptide salmon calcitonin (sCT) directly or indirectly target genetically distinct neurons in the caudal hindbrain (nucleus tractus solitarius and area postrema), rostral hindbrain (lateral parabrachial nucleus), midbrain (lateral dorsal tegmentum and ventral tegmental area) and hypothalamus (arcuate nucleus and parasubthalamic nucleus) via activation of amylin and/or calcitonin receptors. Given that the stable amylin analogue cagrilintide is under clinical development for the treatment of obesity, it is important to determine whether this drug recruits overlapping or distinct central nervous system pathways to that of amylin and sCT with implications for minimising any aversive effects it potentially causes. Such insight will also be important to understand how amylin and sCT analogues synergize with other molecules as part of dual or triple agonist therapies for obesity, especially the glucagon-like peptide 1 receptor (GLP-1R) agonist semaglutide, which has been shown to synergistically lower body weight with cagrilintide (CagriSema) in clinical trials.
Collapse
Affiliation(s)
- Mohammed K Hankir
- Department of Veterinary Physiology, University of Zurich, Zurich, Switzerland; School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland.
| | - Christelle Le Foll
- Department of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
| |
Collapse
|