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1.
Current Aspects of the Role of Autoantibodies Directed Against Appetite-Regulating Hormones and the Gut Microbiome in Eating Disorders.
Smitka, K, Prochazkova, P, Roubalova, R, Dvorak, J, Papezova, H, Hill, M, Pokorny, J, Kittnar, O, Bilej, M, Tlaskalova-Hogenova, H
Frontiers in endocrinology. 2021;:613983
Abstract
The equilibrium and reciprocal actions among appetite-stimulating (orexigenic) and appetite-suppressing (anorexigenic) signals synthesized in the gut, brain, microbiome and adipose tissue (AT), seems to play a pivotal role in the regulation of food intake and feeding behavior, anxiety, and depression. A dysregulation of mechanisms controlling the energy balance may result in eating disorders such as anorexia nervosa (AN) and bulimia nervosa (BN). AN is a psychiatric disease defined by chronic self-induced extreme dietary restriction leading to an extremely low body weight and adiposity. BN is defined as out-of-control binge eating, which is compensated by self-induced vomiting, fasting, or excessive exercise. Certain gut microbiota-related compounds, like bacterial chaperone protein Escherichia coli caseinolytic protease B (ClpB) and food-derived antigens were recently described to trigger the production of autoantibodies cross-reacting with appetite-regulating hormones and neurotransmitters. Gut microbiome may be a potential manipulator for AT and energy homeostasis. Thus, the regulation of appetite, emotion, mood, and nutritional status is also under the control of neuroimmunoendocrine mechanisms by secretion of autoantibodies directed against neuropeptides, neuroactive metabolites, and peptides. In AN and BN, altered cholinergic, dopaminergic, adrenergic, and serotonergic relays may lead to abnormal AT, gut, and brain hormone secretion. The present review summarizes updated knowledge regarding the gut dysbiosis, gut-barrier permeability, short-chain fatty acids (SCFA), fecal microbial transplantation (FMT), blood-brain barrier permeability, and autoantibodies within the ghrelin and melanocortin systems in eating disorders. We expect that the new knowledge may be used for the development of a novel preventive and therapeutic approach for treatment of AN and BN.
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2.
Involvement of Ghrelin Dynamics in Stress-Induced Eating Disorder: Effects of Sex and Aging.
Yamada, C
International journal of molecular sciences. 2021;(21)
Abstract
Stress, a factor that affects appetite in our daily lives, enhances or suppresses appetite and changes palatability. However, so far, the mechanisms underlying the link between stress and eating have not been fully elucidated. Among the peripherally produced appetite-related peptides, ghrelin is the only orexigenic peptide, and abnormalities in the dynamics and reactivity of this peptide are involved in appetite abnormalities in various diseases and psychological states. This review presents an overview of the research results of studies evaluating the effects of various stresses on appetite. The first half of this review describes the relationship between appetite and stress, and the second half describes the relationship between the appetite-promoting peptide ghrelin and stress. The effects of sex differences and aging under stress on appetite are also described.
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Obesity as the Sequel of Childhood Stunting: Ghrelin and GHSR Gene Polymorphism Explained.
Muhammad, HFL
Acta medica Indonesiana. 2018;(2):159-164
Abstract
Stunting or short stature in children is a significant nutritional problem in developing and underdeveloped countries. Stunting during childhood might affect brain development and impair development cognitive function. Additionally, this condition associated with the increased risk for obesity during adulthood. Several studies have shown that the increment risk of obesity and overweight in children with a short stature was due to their metabolic efficiency. Children with stunting have lower resting energy expenditure compared to non stunting children. Additionally, stunted children has higher respiratory quotient and carbohydrate oxidation but lower fat oxidation compared to non-stunting children. These results might explain why stunted children easily become obese, which is due to lower fat oxidation and leading to tendency to store fat.This review discussed the current status on studies in the nutrigenetic aspects of the relationship between stunting in the childhood and obesity in adulthood. I hypothesized that stunted children are more likely to become obese in their later life because they have lower metabolic rate and higher tendency of fat storage. There are several candidate genes and pathway involved in obesity and I suspected that ghrelin and its receptor growth hormone secretague receptor (GHSR) were responsible.
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Acute and Chronic Effects of Exercise on Appetite, Energy Intake, and Appetite-Related Hormones: The Modulating Effect of Adiposity, Sex, and Habitual Physical Activity.
Dorling, J, Broom, DR, Burns, SF, Clayton, DJ, Deighton, K, James, LJ, King, JA, Miyashita, M, Thackray, AE, Batterham, RL, et al
Nutrients. 2018;(9)
Abstract
Exercise facilitates weight control, partly through effects on appetite regulation. Single bouts of exercise induce a short-term energy deficit without stimulating compensatory effects on appetite, whilst limited evidence suggests that exercise training may modify subjective and homeostatic mediators of appetite in directions associated with enhanced meal-induced satiety. However, a large variability in responses exists between individuals. This article reviews the evidence relating to how adiposity, sex, and habitual physical activity modulate exercise-induced appetite, energy intake, and appetite-related hormone responses. The balance of evidence suggests that adiposity and sex do not modify appetite or energy intake responses to acute or chronic exercise interventions, but individuals with higher habitual physical activity levels may better adjust energy intake in response to energy balance perturbations. The effect of these individual characteristics and behaviours on appetite-related hormone responses to exercise remains equivocal. These findings support the continued promotion of exercise as a strategy for inducing short-term energy deficits irrespective of adiposity and sex, as well as the ability of exercise to positively influence energy balance over the longer term. Future well-controlled studies are required to further ascertain the potential mediators of appetite responses to exercise.
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5.
Efficacy of Anamorelin, a Novel Non-Peptide Ghrelin Analogue, in Patients with Advanced Non-Small Cell Lung Cancer (NSCLC) and Cachexia-Review and Expert Opinion.
Currow, DC, Maddocks, M, Cella, D, Muscaritoli, M
International journal of molecular sciences. 2018;(11)
Abstract
Cancer cachexia is a multilayered syndrome consisting of the interaction between tumor cells and the host, at times modulated by the pharmacologic treatments used for tumor control. Key cellular and soluble mediators, activated because of this interaction, induce metabolic and nutritional alterations. This results in mass and functional changes systemically, and can lead to increased morbidity and reduced length and quality of life. For most solid malignancies, a cure remains an unrealistic goal, and targeting the key mediators is ineffective because of their heterogeneity/redundancy. The most beneficial approach is to target underlying systemic mechanisms, an approach where the novel non-peptide ghrelin analogue anamorelin has the advantage of stimulating appetite and possibly food intake, as well as promoting anabolism and significant muscle mass gain. In the ROMANA studies, compared with placebo, anamorelin significantly increased lean body mass in non-small cell lung cancer (NSCLC) patients. Body composition analysis suggested that anamorelin is an active anabolic agent in patients with NSCLC, without the side effects of other anabolic drugs. Anamorelin also induced a significant and meaningful improvement of anorexia/cachexia symptoms. The ROMANA trials have provided unprecedented knowledge, highlighting the therapeutic effects of anamorelin as an initial, but significant, step toward directly managing cancer cachexia.
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Ghrelin, CCK, GLP-1, and PYY(3-36): Secretory Controls and Physiological Roles in Eating and Glycemia in Health, Obesity, and After RYGB.
Steinert, RE, Feinle-Bisset, C, Asarian, L, Horowitz, M, Beglinger, C, Geary, N
Physiological reviews. 2017;(1):411-463
Abstract
The efficacy of Roux-en-Y gastric-bypass (RYGB) and other bariatric surgeries in the management of obesity and type 2 diabetes mellitus and novel developments in gastrointestinal (GI) endocrinology have renewed interest in the roles of GI hormones in the control of eating, meal-related glycemia, and obesity. Here we review the nutrient-sensing mechanisms that control the secretion of four of these hormones, ghrelin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide tyrosine tyrosine [PYY(3-36)], and their contributions to the controls of GI motor function, food intake, and meal-related increases in glycemia in healthy-weight and obese persons, as well as in RYGB patients. Their physiological roles as classical endocrine and as locally acting signals are discussed. Gastric emptying, the detection of specific digestive products by small intestinal enteroendocrine cells, and synergistic interactions among different GI loci all contribute to the secretion of ghrelin, CCK, GLP-1, and PYY(3-36). While CCK has been fully established as an endogenous endocrine control of eating in healthy-weight persons, the roles of all four hormones in eating in obese persons and following RYGB are uncertain. Similarly, only GLP-1 clearly contributes to the endocrine control of meal-related glycemia. It is likely that local signaling is involved in these hormones' actions, but methods to determine the physiological status of local signaling effects are lacking. Further research and fresh approaches are required to better understand ghrelin, CCK, GLP-1, and PYY(3-36) physiology; their roles in obesity and bariatric surgery; and their therapeutic potentials.
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7.
The Role of Ghrelin in Senescence: A Mini-Review.
Yin, Y, Zhang, W
Gerontology. 2016;(2):155-62
Abstract
Ghrelin, a 28-amino acid hormone produced mainly by the X/A-like endocrine cells in gastric mucosa, has a widespread tissue distribution and diverse physiological functions such as hormonal, orexigenic, metabolic, cardiovascular, neurological, and immunological activities. Considerable evidence has suggested that ghrelin plays an important role in organism senescence or aging. The present review provides a comprehensive picture of this new development. We first reviewed the aging (senescence)-dependent reduction of ghrelin signaling, and then highlighted its relationship with the aging-associated alteration in food intake, energy metabolism, cardiovascular function, neurological activity, and adaptive immunity. Our literature review suggests that ghrelin is an innovative and promising agent in the treatment of these pathophysiological conditions associated with senescence.
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8.
Ghrelin and eating disorders.
Atalayer, D, Gibson, C, Konopacka, A, Geliebter, A
Progress in neuro-psychopharmacology & biological psychiatry. 2013;:70-82
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Free full text
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Abstract
There is growing evidence supporting a multifactorial etiology that includes genetic, neurochemical, and physiological components for eating disorders above and beyond the more conventional theories based on psychological and sociocultural factors. Ghrelin is one of the key gut signals associated with appetite, and the only known circulating hormone that triggers a positive energy balance by stimulating food intake. This review summarizes recent findings and several conflicting reports on ghrelin in eating disorders. Understanding these findings and inconsistencies may help in developing new methods to prevent and treat patients with these disorders.
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9.
The role of ghrelin, salivary secretions, and dental care in eating disorders.
Yagi, T, Ueda, H, Amitani, H, Asakawa, A, Miyawaki, S, Inui, A
Nutrients. 2012;(8):967-89
Abstract
Eating disorders, including anorexia and bulimia nervosa, are potentially life-threatening syndromes characterized by severe disturbances in eating behavior. An effective treatment strategy for these conditions remains to be established, as patients with eating disorders tend to suffer from multiple relapses. Because ghrelin was originally discovered in the stomach mucosa, it has been widely studied over the past decade in an effort to uncover its potential roles; these studies have shed light on the mechanism by which ghrelin regulates food intake. Thus, studying ghrelin in the context of eating disorders could improve our understanding of the pathogenesis of eating disorders, possibly resulting in a promising new pharmacological treatment strategy for these patients. In addition, early detection and treatment of eating disorders are critical for ensuring recovery of young patients. Oral symptoms, including mucosal, dental, and saliva abnormalities, are typically observed in the early stages of eating disorders. Although oral care is not directly related to the treatment of eating disorders, knowledge of the oral manifestations of eating disorder patients may aid in early detection, resulting in earlier treatment; thus, oral care might contribute to overall patient management and prognosis. Moreover, ghrelin has also been found in saliva, which may be responsible for oral hygiene and digestion-related functions. This review discusses the pharmacological potential of ghrelin in regulating food-intake and the role of saliva and oral care in young patients with eating disorders.
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10.
Ghrelin, Helicobacter pylori and body mass: is there an association?
Boltin, D, Niv, Y
The Israel Medical Association journal : IMAJ. 2012;(2):130-2
Abstract
Eradication of Helicobacter pylori is accompanied by an array of metabolic and hormonal changes in the host. Weight gain following H. pylori eradication is a poorly understood phenomenon and probably results from an interaction between multiple factors. Ghrelin, a peptide hormone secreted by the stomach, is involved in the regulation of food intake and appetite and may account for some of these changes. Although several observational studies have demonstrated that H. pylori infection suppresses circulating ghrelin levels, it has yet to be proven that ghrelin levels increase following eradication. On the other hand, gastric expression of ghrelin, also suppressed by H. pylori, clearly increases following eradication. The determinants of plasma ghrelin levels remain elusive, as do the effects of eradication on these levels. Weight gain following H. pylori eradication may be attributable to changes in plasma and gastric ghrelin; however, this hypothesis needs to be further investigated.