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Hamamah S, Hajnal A, Covasa M. Influence of Bariatric Surgery on Gut Microbiota Composition and Its Implication on Brain and Peripheral Targets. Nutrients 2024; 16:1071. [PMID: 38613104 PMCID: PMC11013759 DOI: 10.3390/nu16071071] [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: 03/14/2024] [Revised: 03/29/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024] Open
Abstract
Obesity remains a significant global health challenge, with bariatric surgery remaining as one of the most effective treatments for severe obesity and its related comorbidities. This review highlights the multifaceted impact of bariatric surgery beyond mere physical restriction or nutrient malabsorption, underscoring the importance of the gut microbiome and neurohormonal signals in mediating the profound effects on weight loss and behavior modification. The various bariatric surgery procedures, such as Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), act through distinct mechanisms to alter the gut microbiome, subsequently impacting metabolic health, energy balance, and food reward behaviors. Emerging evidence has shown that bariatric surgery induces profound changes in the composition of the gut microbiome, notably altering the Firmicutes/Bacteroidetes ratio and enhancing populations of beneficial bacteria such as Akkermansia. These microbiota shifts have far-reaching effects beyond gut health, influencing dopamine-mediated reward pathways in the brain and modulating the secretion and action of key gut hormones including ghrelin, leptin, GLP-1, PYY, and CCK. The resultant changes in dopamine signaling and hormone levels contribute to reduced hedonic eating, enhanced satiety, and improved metabolic outcomes. Further, post-bariatric surgical effects on satiation targets are in part mediated by metabolic byproducts of gut microbiota like short-chain fatty acids (SCFAs) and bile acids, which play a pivotal role in modulating metabolism and energy expenditure and reducing obesity-associated inflammation, as well as influencing food reward pathways, potentially contributing to the regulation of body weight and reduction in hedonic eating behaviors. Overall, a better understanding of these mechanisms opens the door to developing non-surgical interventions that replicate the beneficial effects of bariatric surgery on the gut microbiome, dopamine signaling, and gut hormone regulation, offering new avenues for obesity treatment.
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Affiliation(s)
- Sevag Hamamah
- Department of Basic Medical Sciences, College of Osteopathic Medicine, Western University of Health Sciences, Pomona, CA 9176, USA;
| | - Andras Hajnal
- Department of Neural and Behavioral Sciences, College of Medicine, The Pennsylvania State University, Hershey, PA 17033, USA;
| | - Mihai Covasa
- Department of Basic Medical Sciences, College of Osteopathic Medicine, Western University of Health Sciences, Pomona, CA 9176, USA;
- Department of Biomedical Sciences, College of Medicine and Biological Science, University of Suceava, 7200229 Suceava, Romania
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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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Albaugh VL, He Y, Münzberg H, Morrison CD, Yu S, Berthoud HR. Regulation of body weight: Lessons learned from bariatric surgery. Mol Metab 2023; 68:101517. [PMID: 35644477 PMCID: PMC9938317 DOI: 10.1016/j.molmet.2022.101517] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/04/2022] [Accepted: 05/21/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Bariatric or weight loss surgery is currently the most effective treatment for obesity and metabolic disease. Unlike dieting and pharmacology, its beneficial effects are sustained over decades in most patients, and mortality is among the lowest for major surgery. Because there are not nearly enough surgeons to implement bariatric surgery on a global scale, intensive research efforts have begun to identify its mechanisms of action on a molecular level in order to replace surgery with targeted behavioral or pharmacological treatments. To date, however, there is no consensus as to the critical mechanisms involved. SCOPE OF REVIEW The purpose of this non-systematic review is to evaluate the existing evidence for specific molecular and inter-organ signaling pathways that play major roles in bariatric surgery-induced weight loss and metabolic benefits, with a focus on Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), in both humans and rodents. MAJOR CONCLUSIONS Gut-brain communication and its brain targets of food intake control and energy balance regulation are complex and redundant. Although the relatively young science of bariatric surgery has generated a number of hypotheses, no clear and unique mechanism has yet emerged. It seems increasingly likely that the broad physiological and behavioral effects produced by bariatric surgery do not involve a single mechanism, but rather multiple signaling pathways. Besides a need to improve and better validate surgeries in animals, advanced techniques, including inducible, tissue-specific knockout models, and the use of humanized physiological traits will be necessary. State-of-the-art genetically-guided neural identification techniques should be used to more selectively manipulate function-specific pathways.
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Affiliation(s)
- Vance L Albaugh
- Translational and Integrative Gastrointestinal and Endocrine Research Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Yanlin He
- Brain Glycemic and Metabolism Control 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
| | - Sangho Yu
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Hans-Rudolf Berthoud
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA.
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Neuman J, Roeder N, Richardson B, Quattrin T, Hamilton J, Thanos PK. High Fat Diet Increases [ 3H] Flunitrazepam Binding in the Mouse Brain that is Dependent on the Expression of the Dopamine D2 Gene. Neurochem Res 2022; 47:3003-3011. [PMID: 35708880 DOI: 10.1007/s11064-022-03644-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/16/2022] [Accepted: 05/22/2022] [Indexed: 11/24/2022]
Abstract
Dopamine is an important neuromodulator in the brain that binds to dopamine D1-like receptors (D1, D5) as well as dopamine D2-like receptors (D2, D3, D4). The D2 receptor is known to play an integral role in a variety of physiological processes including addictive behaviors, locomotion, motivation, feeding behavior, and more. It was recently reported that dopamine is a direct-acting modulator of mammalian GABA(A) receptors. To this end, we wanted to examine how the expression of the dopamine D2 gene impacts the expression of GABA(A) receptors in the brain under different dietary conditions. Adult female Drd2 wild-type (WT), heterozygous (HT), and knockout (KO) mice were given either normal or high-fat diet for a period of 30 weeks. Following this, their brains were collected for [3H] Flunitrazepam binding in order to assess GABA(A) receptor expression. A high fat diet significantly increased [3H] Flunitrazepam binding in the regions of the somatosensory cortex, striatum, and various other cortical areas within WT mice. In contrast, no effect of diet was observed in HT or KO mice. As such, HT and KO mice displayed reduced [3H] Flunitrazepam binding in these areas relative to WT mice under high-fat dietary conditions. The effect of a high-fat diet on [3H] Flunitrazepam binding is consistent with recent evidence showing increases in GABA neurotransmitter levels following a high-fat diet. We demonstrate for the first time that the expression of the D2 gene plays a prominent role in the ability of a high-fat diet to impact GABA(A) receptors in the mouse brain.
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Affiliation(s)
- Josh Neuman
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Nicole Roeder
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Brittany Richardson
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Teresa Quattrin
- University at Buffalo, UBMD Pediatrics, JR Oishei Children's Hospital, Buffalo, NY, USA
| | - John Hamilton
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Panayotis K Thanos
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, State University of New York at Buffalo, Buffalo, NY, USA.
- Department of Psychology, State University at Buffalo, Buffalo, NY, USA.
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Richardson B, Swenson S, Hamilton J, Leonard K, Delis F, Gold M, Blum K, Thanos PK. Chronic neuroleptic treatment combined with a high fat diet elevated [3H] flunitrazepam binding in the cerebellum. Prog Neuropsychopharmacol Biol Psychiatry 2022; 112:110407. [PMID: 34320402 DOI: 10.1016/j.pnpbp.2021.110407] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 06/21/2021] [Accepted: 07/22/2021] [Indexed: 01/29/2023]
Abstract
Clinical and preclinical studies have shown dysfunctions in genetic expression and neurotransmission of γ-Aminobutyric acid (GABA), GABAA receptor subunits, and GABA-synthesizing enzymes GAD67 and GAD65 in schizophrenia. It is well documented that there is significant weight gain after chronic neuroleptic treatment in humans. While there are limited studies on the effects of diet on GABA signaling directly, a change in diet has been used clinically as an adjunct to treatment for schizophrenic relief. In this study, rats chronically consumed either a chow diet (CD) or a 60% high-fat diet (HFD) and drank from bottles that contained one of the following solutions: water, haloperidol (1.5 mg/kg), or olanzapine (10 mg/kg) for four weeks. Rats were then euthanized and their brains were processed for GABAA in-vitro receptor autoradiography using [3H] flunitrazepam. A chronic HFD treatment yielded significantly increased [3H] flunitrazepam binding in the rat cerebellum independent of neuroleptic treatment. The desynchronization between the prefrontal cortex and the cerebellum is associated with major cognitive and motor dysfunctions commonly found in schizophrenic symptomatology, such as slowed reaction time, motor dyscoordination, and prefrontal activations related to speech fluency and cognitive alertness. These data support the notion that there is a dietary effect on GABA signaling within the cerebellum, as well as the importance of considering nutritional intervention methods as an adjunct treatment for patients chronically treated with neuroleptics. Finally, we indicate that future studies involving the analysis of individual patient's genetic profiles will further assist towards a precision medicine approach to the treatment of schizophrenia.
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Affiliation(s)
- 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, NY, USA; Department of Psychology, University at Buffalo, Buffalo, NY, USA
| | - Sabrina Swenson
- 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, NY, USA
| | - 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, NY, USA; Department of Psychology, University at Buffalo, Buffalo, NY, USA
| | - Ken Leonard
- Department of Psychiatry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Foteini Delis
- Department of Pharmacology, University at Ioannina, Ioannina, Greece
| | - Mark Gold
- Washington University in St Louis, School of Medicine, St. Louis, MS, USA
| | - Ken Blum
- Western University Health Sciences, Graduate School of Biomedical Sciences, Pomona, CA, 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, NY, USA; Department of Psychology, University at Buffalo, Buffalo, NY, USA.
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