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ELife May 2022Food intake behavior is regulated by a network of appetite-inducing and appetite-suppressing neuronal populations throughout the brain. The parasubthalamic nucleus...
Food intake behavior is regulated by a network of appetite-inducing and appetite-suppressing neuronal populations throughout the brain. The parasubthalamic nucleus (PSTN), a relatively unexplored population of neurons in the posterior hypothalamus, has been hypothesized to regulate appetite due to its connectivity with other anorexigenic neuronal populations and because these neurons express Fos, a marker of neuronal activation, following a meal. However, the individual cell types that make up the PSTN are not well characterized, nor are their functional roles in food intake behavior. Here, we identify and distinguish between two discrete PSTN subpopulations, those that express tachykinin-1 (PSTN neurons) and those that express corticotropin-releasing hormone (PSTN neurons), and use a panel of genetically encoded tools in mice to show that PSTN neurons play an important role in appetite suppression. Both subpopulations increase activity following a meal and in response to administration of the anorexigenic hormones amylin, cholecystokinin (CCK), and peptide YY (PYY). Interestingly, chemogenetic inhibition of PSTN, but not PSTN neurons, reduces the appetite-suppressing effects of these hormones. Consistently, optogenetic and chemogenetic stimulation of PSTN neurons, but not PSTN neurons, reduces food intake in hungry mice. PSTN and PSTN neurons project to distinct downstream brain regions, and stimulation of PSTN projections to individual anorexigenic populations reduces food consumption. Taken together, these results reveal the functional properties and projection patterns of distinct PSTN cell types and demonstrate an anorexigenic role for PSTN neurons in the hormonal and central regulation of appetite.
Topics: Animals; Appetite; Appetite Regulation; Corticotropin-Releasing Hormone; Eating; Mice; Neurons; Optogenetics
PubMed: 35507386
DOI: 10.7554/eLife.75470 -
Obesity Reviews : An Official Journal... Mar 2023Disrupted hormonal appetite signaling plays a crucial role in obesity as it may lead to uncontrolled reward-related eating. Such disturbances can be induced not only by... (Review)
Review
Disrupted hormonal appetite signaling plays a crucial role in obesity as it may lead to uncontrolled reward-related eating. Such disturbances can be induced not only by weight gain itself but also by glucocorticoid overexposure, for example, due to chronic stress, disease, or medication use. However, the exact pathways are just starting to be understood. Here, we present a conceptual framework of how glucocorticoid excess may impair hormonal appetite signaling and, consequently, eating control in the context of obesity. The evidence we present suggests that counteracting glucocorticoid excess can lead to improvements in appetite signaling and may therefore pose a crucial target for obesity prevention and treatment. In turn, targeting hormonal appetite signals may not only improve weight management and eating behavior but may also decrease detrimental effects of glucocorticoid excess on cardio-metabolic outcomes and mood. We conclude that gaining a better understanding of the relationship between glucocorticoid excess and circulating appetite signals will contribute greatly to improvements in personalized obesity prevention and treatment.
Topics: Humans; Appetite; Glucocorticoids; Feeding Behavior; Obesity; Weight Gain; Eating
PubMed: 36480471
DOI: 10.1111/obr.13539 -
Experimental & Molecular Medicine Apr 2022As the principal means of acquiring nutrients, feeding behavior is indispensable to the survival and well-being of animals. In response to energy or nutrient deficits,... (Review)
Review
As the principal means of acquiring nutrients, feeding behavior is indispensable to the survival and well-being of animals. In response to energy or nutrient deficits, animals seek and consume food to maintain energy homeostasis. On the other hand, even when animals are calorically replete, non-homeostatic factors, such as the sight, smell, and taste of palatable food, or environmental cues that predict food, can stimulate feeding behavior. These homeostatic and non-homeostatic factors have traditionally been investigated separately, but a growing body of literature highlights that these factors work synergistically to promote feeding behavior. Furthermore, recent breakthroughs in cell type-specific and circuit-specific labeling, recording, and manipulation techniques have markedly accelerated the discovery of well-defined neural populations underlying homeostatic and non-homeostatic appetite control, as well as overlapping circuits that contribute to both types of appetite. This review aims to provide an update on our understanding of the neural circuit mechanisms for promoting homeostatic and non-homeostatic appetites, focusing on the function of recently identified, genetically defined cell types.
Topics: Animals; Appetite; Brain; Feeding Behavior; Homeostasis
PubMed: 35474340
DOI: 10.1038/s12276-022-00758-4 -
Journal of Pediatric Psychology May 2023Loss of control eating (LOC) is a dysregulated eating behavior relevant to eating disorders and weight-related health concerns. Hedonic appetite and affect...
OBJECTIVE
Loss of control eating (LOC) is a dysregulated eating behavior relevant to eating disorders and weight-related health concerns. Hedonic appetite and affect (positive/negative) are dynamic microtemporal processes that influence LOC, but they have been studied predominantly in a static, macrotemporal manner. The present study examined associations of hedonic appetite and positive/negative affect, on macrotemporal and microtemporal levels, with LOC in adolescents.
METHODS
Adolescent participants 13-18 years old (n = 43; Mage = 15.1, SD = 1.6; 69.8% female) completed smartphone surveys for 6 evenings, assessing LOC, hedonic appetite, and positive/negative affect. Scores on items were calculated to create microtemporal and macrotemporal assessments of these constructs. Multilevel models were run to examine associations between hedonic appetite and positive/negative affect with LOC.
RESULTS
Both macrotemporal and microtemporal hedonic appetite were significantly positively related to LOC (β = .73, p < .001; β = .47, p < .001, respectively). Macrotemporal positive affect was significantly negatively associated with LOC (β = -.09, p < .001). Macrotemporal negative affect was significantly positively associated with LOC (β = .13, p < .001). No significant relationships emerged between microtemporal positive/negative affect and LOC.
CONCLUSIONS
Hedonic appetite appears to be associated with LOC on both microtemporal and macrotemporal levels, suggesting that both momentary fluctuations and having higher hedonic appetite than others can be risk factors for LOC. However, affect appears to be associated with LOC only at the macrotemporal level. Findings may inform theoretical work and clinical and research assessment strategies.
Topics: Humans; Adolescent; Female; Male; Appetite; Feeding Behavior; Feeding and Eating Disorders; Risk Factors
PubMed: 36763682
DOI: 10.1093/jpepsy/jsad004 -
JAMA Feb 2024
Topics: Food; Appetite; Diet; Feeding Behavior
PubMed: 38411654
DOI: 10.1001/jama.2023.18213 -
Cancer Treatment and Research... 2021This study aims to review the current evidence regarding appetite problem in cancer patients, mainly focusing on pathophysiology, diagnosis, and treatment. (Review)
Review
AIM
This study aims to review the current evidence regarding appetite problem in cancer patients, mainly focusing on pathophysiology, diagnosis, and treatment.
INTRODUCTION
Anorexia is the common symptom of malnutrition in cancer patients. Recently, the understanding of the pathophysiological mechanism of the appetite problem in cancer patients has been increasing that give impact to rigorous research to find the therapies for improving appetite in cancer patients.
DISCUSSION
The development of anorexia in cancer patients is a complex process that involves many cytokines, receptors, chemical mediators/substances, hormones, and peptides. Growth and differentiation factor-15 (GDF-15) and toll-like receptor (TLR-4) have recently been found to be implicated in the pathogenesis of anorexia. To help diagnose the appetite problem in cancer patients, several questionnaires can be used, starting from well-known questionnaires such as Functional Assessment of Anorexia Cachexia Therapy (FAACT), Visual Analog Scale (VAS), European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC-QLQ30). Several drugs with different mechanisms of action have been studied to help in improving appetite in cancer patients. New repurposed agents such as anamorelin, mirtazapine, thalidomide, and eicosapentaenoic acid (EPA) have shown a beneficial effect in improving appetite and quality of life in cancer patients, however more phase 3 clinical trial studies is still needed.
CONCLUSION
The pathophysiology of appetite problems in cancer patients is a complex process that involves many factors. Several drugs that target those factors have been studied, however more phase 3 clinical trial studies are needed to confirm the findings from previous studies.
Topics: Anorexia; Appetite; Clinical Trials, Phase III as Topic; Eicosapentaenoic Acid; Growth Differentiation Factor 15; Humans; Hydrazines; Mirtazapine; Neoplasms; Oligopeptides; Quality of Life; Severity of Illness Index; Surveys and Questionnaires; Thalidomide; Toll-Like Receptor 4; Treatment Outcome
PubMed: 33607591
DOI: 10.1016/j.ctarc.2021.100336 -
The American Journal of Medicine Mar 2024
Topics: Humans; Appetite; Diet; Energy Intake
PubMed: 38049023
DOI: 10.1016/j.amjmed.2023.11.015 -
Journal of Feline Medicine and Surgery Jul 2022
Topics: Animals; Appetite; Cat Diseases; Cats; Feeding and Eating Disorders
PubMed: 35775304
DOI: 10.1177/1098612X221106352 -
Physiology & Behavior May 2020The drive to eat is a component of appetite control, independent of the omnivorous habit of humans, and separate from food choice, satiety and food reward. The drive... (Review)
Review
The drive to eat is a component of appetite control, independent of the omnivorous habit of humans, and separate from food choice, satiety and food reward. The drive forms part of the tonic component of appetite and arises from biological needs; it is distinct from episodic aspects of appetite which are heavily influenced by culture and the environment (and which reflect the omnivorous habit). It is proposed that the tonic drive to eat reflects a need state generated by metabolic energy expenditure (EE) required to maintain the functioning and integrity of vital organs. Specifically, the tonic drive is quantitatively associated with fat-free mass (FFM) and resting metabolic rate (RMR). A rational proposition is that high metabolic rate organs (such as heart, liver, kidneys, brain) together with skeletal muscle generate a metabolic need which drives energy intake (EI). The basic phenomenon of a relationship between FFM, RMR and EI, first published in 2011, has been substantially replicated and there are at least 14 concordant published studies carried out in 9 different countries (and 4 continents) with various ethnic groups of lean and obese humans. These studies demonstrate that FFM and RMR represent major determinants of the drive to eat, and this is rational from an evolutionary perspective. The EE of bodily movements through skeletal muscle activity (namely physical activity and exercise) represents another driver which is clearly but more weakly associated with an increase in EI. This account of appetite control, developed within an energy balance framework, is consistent with the apparent inexorable escalation of fatness in individual humans, and for the progressive increase in the prevalence of obesity which, among other factors, reflects the difficulty of managing the biological drive to eat.
Topics: Appetite; Appetite Regulation; Body Composition; Energy Intake; Energy Metabolism; Humans
PubMed: 32081814
DOI: 10.1016/j.physbeh.2020.112846 -
Philosophical Transactions of the Royal... Oct 2023Despite the large volume and extensive range of obesity research, there is substantial disagreement on the causes and effective preventative strategies. We suggest the... (Review)
Review
Despite the large volume and extensive range of obesity research, there is substantial disagreement on the causes and effective preventative strategies. We suggest the field will benefit from greater emphasis on integrative approaches that examine how various potential contributors interact, rather than regarding them as competing explanations. We demonstrate the application of nutritional geometry, a multi-nutrient integrative framework developed in the ecological sciences, to obesity research. Such studies have shown that humans, like many other species, regulate protein intake more strongly than other dietary components, and consequently if dietary protein is diluted there is a compensatory increase in food intake-a process called protein leverage. The protein leverage hypothesis (PLH) proposes that the dilution of protein in modern food supplies by fat and carbohydrate-rich highly processed foods has resulted in increased energy intake through protein leverage. We present evidence for the PLH from a variety of sources (mechanistic, experimental and observational), and show that this mechanism is compatible with many other findings and theories in obesity research. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.
Topics: Humans; Appetite; Obesity; Nutrients; Food, Processed
PubMed: 37661737
DOI: 10.1098/rstb.2022.0212