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Research Square May 2024Satiation is the physiologic process that regulates meal size and termination, and it is quantified by the calories consumed to reach satiation. Given its role in energy...
Satiation is the physiologic process that regulates meal size and termination, and it is quantified by the calories consumed to reach satiation. Given its role in energy intake, changes in satiation contribute to obesity's pathogenesis. Our study employed a protocolized approach to study the components of food intake regulation including a standardized breakfast, a gastric emptying study, appetite sensation testing, and a satiation measurement by an test. These studies revealed that satiation is highly variable among individuals, and while baseline characteristics, anthropometrics, body composition and hormones, contribute to this variability, these factors do not fully account for it. To address this gap, we explored the role of a germline polygenic risk score, which demonstrated a robust association with satiation. Furthermore, we developed a machine-learning-assisted gene risk score to predict satiation and leveraged this prediction to anticipate responses to anti-obesity medications. Our findings underscore the significance of satiation, its inherent variability, and the potential of a genetic risk score to forecast it, ultimately allowing us to predict responses to different anti-obesity interventions.
PubMed: 38826309
DOI: 10.21203/rs.3.rs-4402499/v1 -
Appetite May 2024Terminating a meal after achieving satiation is a critical step in maintaining a healthy energy balance. Despite the extensive collection of information over the last... (Review)
Review
Terminating a meal after achieving satiation is a critical step in maintaining a healthy energy balance. Despite the extensive collection of information over the last few decades regarding the neural mechanisms controlling overall eating, the mechanism underlying different temporal phases of eating behaviors, especially satiation, remains incompletely understood and is typically embedded in studies that measure the total amount of food intake. In this review, we summarize the neural circuits that detect and integrate satiation signals to suppress appetite, from interoceptive sensory inputs to the final motor outputs. Due to the well-established role of cholecystokinin (CCK) in regulating the satiation, we focus on the neural circuits that are involved in regulating the satiation effect caused by CCK. We also discuss several general principles of how these neural circuits control satiation, as well as the limitations of our current understanding of the circuits function. With the application of new techniques involving sophisticated cell-type-specific manipulation and mapping, as well as real-time recordings, it is now possible to gain a better understanding of the mechanisms specifically underlying satiation.
PubMed: 38801994
DOI: 10.1016/j.appet.2024.107512 -
Neuron May 2024Hungry animals need compensatory mechanisms to maintain flexible brain function, while modulation reconfigures circuits to prioritize resource seeking. In Drosophila,...
Hungry animals need compensatory mechanisms to maintain flexible brain function, while modulation reconfigures circuits to prioritize resource seeking. In Drosophila, hunger inhibits aversively reinforcing dopaminergic neurons (DANs) to permit the expression of food-seeking memories. Multitasking the reinforcement system for motivation potentially undermines aversive learning. We find that chronic hunger mildly enhances aversive learning and that satiated-baseline and hunger-enhanced learning require endocrine adipokinetic hormone (AKH) signaling. Circulating AKH influences aversive learning via its receptor in four neurons in the ventral brain, two of which are octopaminergic. Connectomics revealed AKH receptor-expressing neurons to be upstream of several classes of ascending neurons, many of which are presynaptic to aversively reinforcing DANs. Octopaminergic modulation of and output from at least one of these ascending pathways is required for shock- and bitter-taste-reinforced aversive learning. We propose that coordinated enhancement of input compensates for hunger-directed inhibition of aversive DANs to preserve reinforcement when required.
PubMed: 38795709
DOI: 10.1016/j.neuron.2024.04.035 -
Complementary Therapies in Medicine Jun 2024Acupuncture stands out as a prominent complementary and alternative medicine therapy employed for functional dyspepsia (FD). We conducted a Bayesian meta-analysis to... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Acupuncture stands out as a prominent complementary and alternative medicine therapy employed for functional dyspepsia (FD). We conducted a Bayesian meta-analysis to ascertain both the relative effectiveness and safety of various acupuncture methods in the treatment of functional dyspepsia.
METHODS
We systematically searched eight electronic databases, spanning from their inception to April 2023. The eligibility criteria included randomized controlled trials investigating acupuncture treatments for FD. Study appraisal was conducted using the Cochrane risk of bias tool. Pairwise and network meta-analyses were conducted using RevMan 5.3 and ADDIS V.1.16.6 software. Bayesian network meta-analysis was performed to compare and rank the efficacy of different acupuncture therapies for FD symptoms.
RESULTS
This study found that combining different acupuncture methods or using acupuncture in conjunction with Western medicine is more effective in improving symptoms of functional dyspepsia compared to using Western medicine alone. According to the comprehensive analysis results, notably, the combination of Western medicine and acupuncture exhibited superior efficacy in alleviating early satiation and postprandial fullness symptoms. For ameliorating epigastric pain, acupuncture combined with moxibustion proved to be the most effective treatment, while moxibustion emerged as the optimal choice for addressing burning sensations. Warming needle was identified as the preferred method for promoting motilin levels.
CONCLUSION
The findings of this study demonstrate that acupuncture, both independently and in conjunction with other modalities, emerged as a secure and effective treatment option for patients with functional dyspepsia.
Topics: Humans; Acupuncture Therapy; Bayes Theorem; Dyspepsia; Randomized Controlled Trials as Topic
PubMed: 38761869
DOI: 10.1016/j.ctim.2024.103051 -
Appetite May 2024Dietary protein modulates food intake (FI) via unclear mechanism(s). One possibility is that higher protein leads to greater post-ingestive heat production (Specific...
Dietary protein modulates food intake (FI) via unclear mechanism(s). One possibility is that higher protein leads to greater post-ingestive heat production (Specific dynamic action: SDA) leading to earlier meal termination (increased satiation), and inhibition of further intake (increased satiety). The influence of dietary protein on feeding behaviour in C57BL/6J mice was tested using an automated FI monitoring system (BioDAQ), simultaneous to body temperature (T). Total FI, inter meal intervals (IMI, satiety) and meal size (MS, satiation) were related to changes in T after consuming low (5%, LP), moderate (15%, MP) and high (30%, HP) protein diets. Diets were tested over three conditions: 1) room temperature (RT, 21 ± 1 °C), 2) room temperature and running wheels (RTRW) and 3) low temperature (10 °C) and running wheels (LTRW). The differences between diets and conditions were also compared using mixed models. Mice housed at RT fed HP diet, reduced total FI compared with LP and MP due to earlier meal termination (satiation effect). FI was lowered in RTRW conditions with no differences between diets. FI significantly increased under LTRW conditions for all diets, with protein content leading to earlier meal termination (satiation) but not the intervals between feeding bouts (satiety). T fell immediately after feeding in all conditions. Despite a reduction in total FI in mice fed HP, mediated via increased satiation, this effect was not linked to increased T during meals. We conclude effects of dietary protein on intake are not mediated via SDA and T.
PubMed: 38759755
DOI: 10.1016/j.appet.2024.107421 -
BioRxiv : the Preprint Server For... Apr 2024Obesity is a growing global health epidemic with limited effective therapeutics. Serotonin (5-HT) is one major neurotransmitter which remains an excellent target for new...
Obesity is a growing global health epidemic with limited effective therapeutics. Serotonin (5-HT) is one major neurotransmitter which remains an excellent target for new weight-loss therapies, but there remains a gap in knowledge on the mechanisms involved in 5-HT produced in the dorsal Raphe nucleus (DRN) and its involvement in meal initiation. Using a closed-loop optogenetic feeding paradigm, we showed that the 5-HT→arcuate nucleus (ARH) circuit plays an important role in regulating meal initiation. Incorporating electrophysiology and ChannelRhodopsin-2-Assisted Circuit Mapping, we demonstrated that 5-HT neurons receive inhibitory input partially from GABAergic neurons in the DRN, and the 5-HT response to GABAergic inputs can be enhanced by hunger. Additionally, deletion of the GABA receptor subunit in 5-HT neurons inhibits meal initiation with no effect on the satiation process. Finally, we identified the instrumental role of dopaminergic inputs via dopamine receptor D2 in 5-HT neurons in enhancing the response to GABA-induced feeding. Thus, our results indicate that 5-HT neurons are inhibited by synergistic inhibitory actions of GABA and dopamine, which allows for the initiation of a meal.
PubMed: 38746314
DOI: 10.1101/2024.04.26.591360 -
PloS One 2024Current research suggests that energy transfer through human milk influences infant nutritional development and initiates metabolic programming, influencing eating...
The milk study protocol: A longitudinal, prospective cohort study of the relationship between human milk metabolic hormone concentration, maternal body composition, and early growth and satiety development in Samoan infants aged 1-4 months.
BACKGROUND
Current research suggests that energy transfer through human milk influences infant nutritional development and initiates metabolic programming, influencing eating patterns into adulthood. To date, this research has predominantly been conducted among women in high income settings and/or among undernourished women. We will investigate the relationship between maternal body composition, metabolic hormones in human milk, and infant satiety to explore mechanisms of developmental satiety programming and implications for early infant growth and body composition in Samoans; a population at high risk and prevalence for overweight and obesity. Our aims are (1) to examine how maternal body composition influences metabolic hormone transfer from mother to infant through human milk, and (2) to examine the influences of maternal metabolic hormone transfer and infant feeding patterns on early infant growth and satiety.
METHODS
We will examine temporal changes in hormone transfers to infants through human milk in a prospective longitudinal cohort of n = 80 Samoan mother-infant dyads. Data will be collected at three time points (1, 3, & 4 months postpartum). At each study visit we will collect human milk and fingerpick blood samples from breastfeeding mother-infant dyads to measure the hormones leptin, ghrelin, and adiponectin. Additionally, we will obtain body composition measurements from the dyad, observe breastfeeding behavior, conduct semi-structured interviews, and use questionnaires to document infant hunger and feeding cues and satiety responsiveness. Descriptive statistics, univariate and multivariate analyses will be conducted to address each aim.
DISCUSSION
This research is designed to advance our understanding of variation in the developmental programming of satiety and implications for early infant growth and body composition. The use of a prospective longitudinal cohort alongside data collection that utilizes a mixed methods approach will allow us to capture a more accurate representation on both biological and cultural variables at play in a population at high risk of overweight and obesity.
Topics: Humans; Milk, Human; Female; Infant; Body Composition; Prospective Studies; Longitudinal Studies; Leptin; Adiponectin; Adult; Ghrelin; Child Development; Male; Breast Feeding; Infant Nutritional Physiological Phenomena; Satiation; Mothers
PubMed: 38728264
DOI: 10.1371/journal.pone.0292997 -
Acta Psychologica Jun 2024Affective flexibility is defined as a complex executive function which enables individuals to successfully alternate between distinct emotional and non-emotional... (Review)
Review
Affective flexibility is defined as a complex executive function which enables individuals to successfully alternate between distinct emotional and non-emotional features of a given situation in order to attain a specific goal. A large body of research has focused exclusively on flexibility in a non-emotional context, although most of our interactions with our environment are emotionally satiated. Our main aim was to propose a hierarchical framework to describe this construct from a macro-level perspective to a more nuanced and micro-level perspective, including three different levels of affective flexibility: elementary, shifting, and generative. Next, we employed this hierarchical framework to examine the role played by affective flexibility in typical development and different forms of developmental psychopathology. Lastly, we discuss how this knowledge could inform future prevention and intervention programs aimed at reducing cognitive vulnerability to developmental psychopathology.
Topics: Humans; Executive Function; Child Development; Affect; Models, Psychological; Child
PubMed: 38703655
DOI: 10.1016/j.actpsy.2024.104275 -
Veterinary Medicine and Science May 2024In this study, we investigated the effects of swimming activity and feed restriction on digestion and antioxidant enzyme activities in juvenile rainbow trout (average...
Effects of swimming activity and feed restriction on antioxidant and digestive enzymes in juvenile rainbow trout: Implications for nutritional and exercise strategies in aquaculture.
BACKGROUND
In this study, we investigated the effects of swimming activity and feed restriction on digestion and antioxidant enzyme activities in juvenile rainbow trout (average body weight of 26.54 ± 0.36 g).
METHODS
The stomach, liver and kidney tissues were obtained from four distinct groups: the static water group (fish were kept in static water and fed to satiation), the feeding restricted group (fish were kept in static water with a 25% feed restriction), the swimming exercised group (fish were forced to swimming at a flow rate of 1 Body Length per second (BL/s)) and the swimming exercised-feed restricted group (subjected to swimming exercise at a 1 BL/s flow rate along with a 25% feed restriction). We determined the levels of glutathione, lipid peroxidation and the activities of catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and lactate dehydrogenase, as well as the presence of reactive oxygen species in the tissues obtained from the fish. Additionally, the activities of pepsin, protease, lipase and arginase in these tissues were measured.
RESULTS
Swimming activity and feed restriction showed different effects on the enzyme activities of the fish in the experimental groups.
CONCLUSION
It can be concluded that proper nutrition and exercise positively influence the antioxidant system and enzyme activities in fish, reducing the formation of free radicals. This situation is likely to contribute to the fish's development.
Topics: Animals; Oncorhynchus mykiss; Swimming; Antioxidants; Aquaculture; Physical Conditioning, Animal; Food Deprivation; Animal Nutritional Physiological Phenomena; Digestion; Animal Feed; Liver
PubMed: 38695249
DOI: 10.1002/vms3.1466 -
Animal Welfare (South Mimms, England) 2024Dairy calves are typically fed restricted amounts of milk. Although feed restrictions are predicted to result in negative affective states, the relative aversiveness of...
Dairy calves are typically fed restricted amounts of milk. Although feed restrictions are predicted to result in negative affective states, the relative aversiveness of 'hunger' remains largely unexplored in this species. Here, we investigated whether the conditioned place preference paradigm can be used to explore how calves feel when experiencing different levels of satiation. This paradigm provides insight into what animals remember from past experiences, the assumption being that individuals will prefer places associated with more pleasant or less unpleasant experiences. Sixteen Holstein calves were either fed a restricted (3 L per meal totalling 6 L per day) or 'enhanced' milk allowance ( up to 6 L per meal totalling up to 12 L per day) in their home-pen. Calves were then placed in a conditioning pen for 4 h immediately after being fed their morning meal to allow them to develop an association between the pen and their state of post-prandial satiation. Calves were conditioned across four days with their satiation state alternating between days to allow them to develop an association between pen and satiation levels. On the 5th day, calves were individually allowed to roam freely between the two pens for 30 min. We expected that calves would prefer the pen where they previously experienced higher levels of satiation, but our results show no to limited effects of treatment. However, some methodological issues (colour and side bias) prevent us from drawing strong conclusions. We discuss reasons for these issues and potential solutions to avoid these in future studies.
PubMed: 38694488
DOI: 10.1017/awf.2024.24