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1.
Mechanisms controlling hormone secretion in human gut and its relevance to metabolism.
Martin, AM, Sun, EW, Keating, DJ
The Journal of endocrinology. 2019;(1):R1-R15
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Abstract
The homoeostatic regulation of metabolism is highly complex and involves multiple inputs from both the nervous and endocrine systems. The gut is the largest endocrine organ in our body and synthesises and secretes over 20 different hormones from enteroendocrine cells that are dispersed throughout the gut epithelium. These hormones include GLP-1, PYY, GIP, serotonin, and CCK, each of whom play pivotal roles in maintaining energy balance and glucose homeostasis. Some are now the basis of several clinically used glucose-lowering and weight loss therapies. The environment in which these enteroendocrine cells exist is also complex, as they are exposed to numerous physiological inputs including ingested nutrients, circulating factors and metabolites produced from neighbouring gut microbiome. In this review, we examine the diverse means by which gut-derived hormones carry out their metabolic functions through their interactions with different metabolically important organs including the liver, pancreas, adipose tissue and brain. Furthermore, we discuss how nutrients and microbial metabolites affect gut hormone secretion and the mechanisms underlying these interactions.
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2.
Effect of physical exercise and training on gastrointestinal hormones in populations with different weight statuses.
Zouhal, H, Sellami, M, Saeidi, A, Slimani, M, Abbassi-Daloii, A, Khodamoradi, A, El Hage, R, Hackney, AC, Ben Abderrahman, A
Nutrition reviews. 2019;(7):455-477
Abstract
Several types of hormones exert control over appetite in humans. This narrative review explores the effects of exercise and training on the concentrations of gastrointestinal hormones in healthy and obese individuals. It focuses on the major hormones of appetite regulation: ghrelin, glucagon-like peptide 1, peptide YY, cholecystokinin, leptin, and oxyntomodulin. In normal-weight and overweight individuals, responses to most of these hormones depend on the intensity of exercise and training. However, findings in obese individuals are limited in number and, to some degree, contradictory. Although some gastrointestinal hormones have been studied extensively (eg, leptin), most have not been investigated systematically. Further research is required to confirm the effectiveness of exercise and training on gut hormones and to better understand the effect of gut hormones on appetite and hunger suppression in individuals with obesity. Investigations to elucidate the impact of various forms of exercise that have recently engaged the public interest, eg, high-intensity interval training or concurrent aerobic and resistance training, are warranted.
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Will medications that mimic gut hormones or target their receptors eventually replace bariatric surgery?
Kokkinos, A, Tsilingiris, D, le Roux, CW, Rubino, F, Mantzoros, CS
Metabolism: clinical and experimental. 2019;:153960
Abstract
Bariatric surgery is currently the most effective therapeutic modality through which sustained beneficial effects on weight loss and metabolic improvement are achieved. During recent years, indications for bariatric surgery have been expanded to include cases of poorly controlled type 2 (T2DM) diabetes mellitus in lesser extremes of body weight. A spectrum of the beneficial effects of surgery is attributed to robust changes of postprandial gut peptide responses that are observed post operatively. Consolidated knowledge regarding gut peptide physiology as well as emerging new evidence shedding light on the mode of action of previously overlooked gut hormones provide appealing potential obesity and T2DM therapeutic perspectives. The accumulation of evidence from the effect of exogenous administration of native gut peptides alone or in combinations to humans as well as the development of mimetic agents exerting agonistic effects on combinations of gut hormone receptors pave the way for future integrated gut peptide-based treatments, which may mimic the effects of bariatric surgery.
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Diet in Irritable Bowel Syndrome (IBS): Interaction with Gut Microbiota and Gut Hormones.
El-Salhy, M, Hatlebakk, JG, Hausken, T
Nutrients. 2019;(8)
Abstract
Diet plays an important role not only in the pathophysiology of irritable bowel syndrome (IBS), but also as a tool that improves symptoms and quality of life. The effects of diet seem to be a result of an interaction with the gut bacteria and the gut endocrine cells. The density of gut endocrine cells is low in IBS patients, and it is believed that this abnormality is the direct cause of the symptoms seen in IBS patients. The low density of gut endocrine cells is probably caused by a low number of stem cells and low differentiation progeny toward endocrine cells. A low fermentable oligo-, di-, monosaccharide, and polyol (FODMAP) diet and fecal microbiota transplantation (FMT) restore the gut endocrine cells to the level of healthy subjects. It has been suggested that our diet acts as a prebiotic that favors the growth of a certain types of bacteria. Diet also acts as a substrate for gut bacteria fermentation, which results in several by-products. These by-products might act on the stem cells in such a way that the gut stem cells decrease, and consequently, endocrine cell numbers decrease. Changing to a low-FODMAP diet or changing the gut bacteria through FMT improves IBS symptoms and restores the density of endocrine cells.
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5.
Gastrointestinal hormones in regulation of memory.
Mandal, A, Prabhavalkar, KS, Bhatt, LK
Peptides. 2018;:16-25
Abstract
The connection between the gastrointestinal hormones and the brain has been established many years ago. This relation is termed the gut-brain axis (GBA). The GBA is a bidirectional communication which not only regulates gastrointestinal homeostasis but is also linked with higher emotional and cognitive functions. Hypothalamus plays a critical role in the regulation of energy metabolism, nutrient partitioning and control of feeding behaviors. Various gut hormones are released inside the gastrointestinal tract on food intake. These hormones act peripherally and influence the different responses of the tissues to the food intake, but do also have effects on the brain. The hypothalamus, in turn, integrates visceral function with limbic system structures such as hippocampus, amygdala, and cerebral cortex. The hippocampus has been known for its involvement in the cognitive function and the modulation of synaptic plasticity. This review aims to establish the role of various gut hormones in learning and memory, through the interaction of various receptors in the hippocampus. Understanding their role in memory can also aid in finding novel therapeutic strategies for the treatment of the neurological disorders associated with memory dysfunctions.
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Just a Gut Feeling: Central Nervous Effects of Peripheral Gastrointestinal Hormones.
Roth, CL, Doyle, RP
Endocrine development. 2017;:100-123
Abstract
Despite greater health education, obesity remains one of the greatest health challenges currently facing the world. The prevalence of obesity among children and adolescents and the rising rates of prediabetes and diabetes are of particular concern. A deep understanding of regulatory pathways and development of new anti-obesity drugs with increased efficacy and safety are of utmost necessity. The 2 major biological players in the regulation of food intake are the gut and the brain as peptides released from the gut in response to meals convey information about the energy needs to brain centers of energy homeostasis. There is evidence that gut hormones not only pass the blood-brain barrier and bind to receptors located in different brain areas relevant for body weight regulation, but some are also expressed in the brain as part of hedonic and homeostatic pathways. Regarding obesity interventions, the only truly effective treatment for obesity is bariatric surgery, the long-term benefits of which may actually involve increased activity of gut hormones including peptide YY3-36 and glucagon-like peptide 1. This review discusses critical gut-hormones involved in the regulation of food intake and energy homeostasis and their effects on peripheral tissues versus central nervous system actions.
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7.
Neuroendocrinology of Adipose Tissue and Gut-Brain Axis.
Matafome, P, Eickhoff, H, Letra, L, Seiça, R
Advances in neurobiology. 2017;:49-70
Abstract
Food intake and energy expenditure are closely regulated by several mechanisms which involve peripheral organs and nervous system, in order to maintain energy homeostasis.Short-term and long-term signals express the size and composition of ingested nutrients and the amount of body fat, respectively. Ingested nutrients trigger mechanical forces and gastrointestinal peptide secretion which provide signals to the brain through neuronal and endocrine pathways. Pancreatic hormones also play a role in energy balance exerting a short-acting control regulating the start, end, and composition of a meal. In addition, insulin and leptin derived from adipose tissue are involved in long-acting adiposity signals and regulate body weigh as well as the amount of energy stored as fat over time.This chapter focuses on the gastrointestinal-, pancreatic-, and adipose tissue-derived signals which are integrated in selective orexigenic and anorexigenic brain areas that, in turn, regulate food intake, energy expenditure, and peripheral metabolism.
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8.
The Role of Gut Hormones in Diet-Induced Weight Change: A Systematic Review.
Zhao, X, Han, Q, Gang, X, Lv, Y, Liu, Y, Sun, C, Wang, G
Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme. 2017;(11):816-825
Abstract
Gut hormones are known to play an important role in long-term weight loss maintenance after bariatric surgery. However, the interplay between gut hormones and diet-induced weight changes remains unclear. Our aims were to evaluate the alterations of gut hormones in diet-induced weight loss, weight maintenance, and weight regain periods. Available studies were searched on MEDLINE, EMASE, ClinicalTrials.gov, the Cochrane Library, and Web of science from inception to October 2016. After selection, 16 studies with 656 participants were included. Based on current evidence, we found significant alterations of gut hormones induced by different diets. In weight-loss diets, decreased fasting total PYY, GLP-1, CCK, GIP, PP, and amylin along with increased ghrelin levels were observed in most studies. After weight loss, the persistent decreases of fasting total PYY and GLP-1 levels as well as increased appetite were reported, suggesting the profound impact of altered gut hormones on later weight regain after dietary intervention. The differences between diet-induced changes in gut hormones and other treatments such as bariatric surgery and exercise are also discussed in this review. Although significant alterations of gut hormones were found during weight changes, huge heterogeneity exists in methods and populations. More large-scale studies with elaborate design addressing the gut hormone alterations in dietary weight regulation are required in the future.
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9.
Role of gastrointestinal hormones in feeding behavior and obesity treatment.
Kairupan, TS, Amitani, H, Cheng, KC, Runtuwene, J, Asakawa, A, Inui, A
Journal of gastroenterology. 2016;(2):93-103
Abstract
Food intake regulation is generally evaluated by many aspects consisting of complex mechanisms, including homeostatic regulatory mechanism, which is based on negative feedback, and hedonic regulatory mechanism, which is driven by a reward system. One important aspect of food intake regulation is the peripheral hormones that are secreted from the gastrointestinal tract. These hormones are secreted from enteroendocrine cells as feedback to nutrient and energy intake, and will communicate with the brain directly or via the vagus nerve. Gastrointestinal hormones are very crucial in maintaining a steady body weight, despite variations in nutrient intake and energy expenditure. In this review, we provide an overview of the regulation of feeding behavior by gut hormones, and its role in obesity treatments.
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10.
Obesity: An overview of possible role(s) of gut hormones, lipid sensing and gut microbiota.
Mishra, AK, Dubey, V, Ghosh, AR
Metabolism: clinical and experimental. 2016;(1):48-65
Abstract
Obesity is one of the major challenges for public health in 21st century, with 1.9 billion people being considered as overweight and 600 million as obese. There are certain diseases such as type 2 diabetes, hypertension, cardiovascular disease, and several forms of cancer which were found to be associated with obesity. Therefore, understanding the key molecular mechanisms involved in the pathogenesis of obesity could be beneficial for the development of a therapeutic approach. Hormones such as ghrelin, glucagon like peptide 1 (GLP-1) peptide YY (PYY), pancreatic polypeptide (PP), cholecystokinin (CCK) secreted by an endocrine organ gut, have an intense impact on energy balance and maintenance of homeostasis by inducing satiety and meal termination. Glucose and energy homeostasis are also affected by lipid sensing in which different organs respond in different ways. However, there is one common mechanism i.e. formation of esterified lipids (long chain fatty acyl CoAs) and the activation of protein kinase C δ (PKC δ) involved in all these organs. The possible role of gut microbiota and obesity has been addressed by several researchers in recent years, indicating the possible therapeutic approach toward the management of obesity by the introduction of an external living system such as a probiotic. The proposed mechanism behind this activity is attributed by metabolites produced by gut microbial organisms. Thus, this review summarizes the role of various physiological factors such as gut hormone and lipid sensing involved in various tissues and organ and most important by the role of gut microbiota in weight management.