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Neuroscience and Biobehavioral Reviews Sep 2017The brain-gut-axis is an interdependent system affecting neural functions and controlling our eating behaviour. In recent decades, neuroimaging techniques have... (Review)
Review
The brain-gut-axis is an interdependent system affecting neural functions and controlling our eating behaviour. In recent decades, neuroimaging techniques have facilitated its investigation. We systematically looked into functional and neurochemical brain imaging studies investigating how key molecules such as ghrelin, glucagon-like peptide-1 (GLP-1), peptide tyrosine-tyrosine (PYY), cholecystokinin (CCK), leptin, glucose and insulin influence the function of brain regions regulating appetite and satiety. Of the 349 studies published before July 2016 identified in the database search, 40 were included (27 on healthy and 13 on obese subjects). Our systematic review suggests that the plasma level of ghrelin, the gut hormone promoting appetite, is positively correlated with activation in the pre-frontal cortex (PFC), amygdala and insula and negatively correlated with activation in subcortical areas such as the hypothalamus. In contrast, the plasma levels of glucose, insulin, leptin, PYY, GLP-1 affect the same brain regions conversely. Our study integrates previous investigations of the gut-brain matrix during food-intake and homeostatic regulation and may be of use for future meta-analyses of brain-gut interactions.
Topics: Appetite; Brain; Gastrointestinal Tract; Hormones; Humans; Satiation
PubMed: 28669754
DOI: 10.1016/j.neubiorev.2017.06.013 -
Obesity Reviews : An Official Journal... Feb 2023Determining if gastrointestinal (GI) hormone response to food intake differs between individuals with, and without, obesity may improve our understanding of obesity... (Meta-Analysis)
Meta-Analysis Review
Determining if gastrointestinal (GI) hormone response to food intake differs between individuals with, and without, obesity may improve our understanding of obesity pathophysiology. A systematic review and meta-analysis of studies assessing the concentrations of GI hormones, as well as appetite ratings, following a test meal, in individuals with and without obesity was undertaken. Systematic searches were conducted in the databases MEDLINE, Embase, Cochrane Library, PsycINFO, Web of Science, and ClinicalTrials.gov. A total of 7514 unique articles were retrieved, 115 included in the systematic review, and 70 in the meta-analysis. The meta-analysis compared estimated standardized mean difference in GI hormones' concentration, as well as appetite ratings, between individuals with and without obesity. Basal and postprandial total ghrelin concentrations were lower in individuals with obesity compared with controls, and this was reflected by lower postprandial hunger ratings in the former. Individuals with obesity had a lower postprandial concentration of total peptide YY compared with controls, but no significant differences were found for glucagon-like peptide 1, cholecystokinin, or other appetite ratings. A large methodological and statistical heterogeneity among studies was found. More comprehensive studies are needed to understand if the differences observed are a cause or a consequence of obesity.
Topics: Humans; Appetite; Gastrointestinal Hormones; Obesity; Ghrelin; Peptide YY; Cholecystokinin; Postprandial Period
PubMed: 36416279
DOI: 10.1111/obr.13531 -
The American Journal of Clinical... Mar 2009Disturbances in gastrointestinal hormones have been widely identified in persons with eating disorders (EDs) and have been implicated in their clinical pathologies. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Disturbances in gastrointestinal hormones have been widely identified in persons with eating disorders (EDs) and have been implicated in their clinical pathologies.
OBJECTIVE
The objective was to identify, critically examine, and summarize studies investigating the short-term response of gastrointestinal hormones to food in persons with an ED, including the subtypes anorexia nervosa and bulimia nervosa.
DESIGN
A priori inclusion and exclusion criteria were set and included a procedure in which a test meal or glucose load was given and blood hormone concentrations measured. All studies included a healthy control group for comparison. The outcome variable was defined as the mean difference between fasting plasma hormone concentrations and the maximum postprandial peak or nadir. The difference in baseline values between groups was also examined. Pooled standardized mean differences were calculated and analyzed where possible.
RESULTS
A total of 28 studies were identified, including sufficient studies to perform a meta-analysis for ghrelin, peptide YY, cholecystokinin, insulin, and pancreatic polypeptide. Persons with an ED had higher baseline concentrations of ghrelin (large effect), peptide YY (medium effect), and cholecystokinin (medium effect for ED, large effect for anorexia nervosa). The response of insulin to food was decreased in persons with an ED (medium effect). No further differences were found in the release of gut peptides to a standardized test meal.
CONCLUSIONS
All of the studies had low power for the different subtypes of EDs. High heterogeneity among the studies was observed, and limitations are discussed. The findings suggest that the physiologic changes observed in patients with EDs are highly variable and subject to multiple confounding factors.
Topics: Cholecystokinin; Feeding and Eating Disorders; Gastrointestinal Hormones; Gastrointestinal Tract; Ghrelin; Humans; Insulin; Pancreatic Polypeptide; Peptide YY
PubMed: 19176730
DOI: 10.3945/ajcn.2008.27056 -
Journal of Diabetes and Metabolic... Jun 2020Previous studies have shown thylakoids, the membrane proteins which are extracted from green leaves like spinach, can induce satiety through homeostatic and... (Review)
Review
BACKGROUND
Previous studies have shown thylakoids, the membrane proteins which are extracted from green leaves like spinach, can induce satiety through homeostatic and non-homeostatic pathways. In this study, we reviewed the current human literature on thylakoids' characteristics and their relationship to satiety regulation and weight loss.
METHODS
A systematic search of literature published between January 1990 and May 2019 was conducted on the electronic databases; including WEB OF SCIENCE, Cochrane Library, MEDLINE, Scopus, and EMBASE databases. We included all clinical trials that addressed the effects of thylakoids or chloroplast intake on satiety and weight loss.
RESULTS
After excluding non-human studies, non-RCTs, duplications, studies with irrelevant data and interventions, eight studies were included in the qualitative synthesis. All studies supported this hypothesis that thylakoids reduce the feeling of hunger by increasing postprandial cholecystokinin and leptin and decreasing serum ghrelin, but the consequences of thylakoid intake on anthropometric characteristics were controversial.
CONCLUSION
In conclusion, our results may approve this postulation that receiving a thylakoid-enriched meal can decrease appetite and probably food intake in short term; however, more studies are needed to explore the effects of long term supplementation with thylakoids on weight loss in human subjects.
PubMed: 32550209
DOI: 10.1007/s40200-019-00443-w -
Aging Clinical and Experimental Research Jul 2020Ageing is associated with reduced appetite and energy intakes. However, the mechanisms underlying this phenomenon are not fully understood. This systematic review and... (Meta-Analysis)
Meta-Analysis
Ageing is associated with reduced appetite and energy intakes. However, the mechanisms underlying this phenomenon are not fully understood. This systematic review and meta-analysis quantified differences in circulating concentrations of appetite-related hormones between healthy older and younger adults. Six databases were searched through 12th June 2018 for studies that compared appetite-related hormone concentrations between older and younger adults. Data were pooled using random-effects meta-analysis and are presented as standardised mean difference (Hedges' g) with 95% confidence intervals (95% CI). Thirty-five studies were included involving 710 older adults (mean ± SD; age: 73 ± 5 years) and 713 younger adults (age: 28 ± 7 years). Compared with younger adults, older adults exhibited higher fasted and postprandial concentrations of the anorectic hormones cholecystokinin (Fasted: SMD 0.41 (95% CI 0.24, 0.57); p < 0.001. Postprandial: SMD 0.41 (0.20, 0.62); p < 0.001), leptin [Fasted: SMD 1.23 (0.15, 2.30); p = 0.025. Postprandial: SMD 0.62 (0.23, 1.01); p = 0.002] and insulin [Fasted: SMD 0.24 (- 0.02, 0.50); p = 0.073. Postprandial: SMD 0.16 (0.01, 0.32); p = 0.043]. Higher postprandial concentrations of peptide-YY were also observed in older adults compared with younger adults [SMD 0.31 (- 0.03, 0.65); p = 0.075]. Compared with younger adults, older adults had lower energy intakes [SMD - 0.98 (- 1.74, - 0.22); p = 0.011], and lower hunger perceptions in the fasted [SMD - 1.00 (- 1.54, - 0.46); p < 0.001] and postprandial states [SMD - 0.31, (- 0.64, 0.02); p = 0.064]. Higher circulating concentrations of insulin, leptin, cholecystokinin and peptide-YY accord with reduced appetite and energy intakes in healthy older adults. Interventions to reduce circulating levels of these hormones may be beneficial for combatting the anorexia of ageing.
Topics: Adult; Aged; Appetite; Energy Intake; Fasting; Hormones; Humans; Postprandial Period; Young Adult
PubMed: 31432431
DOI: 10.1007/s40520-019-01292-6 -
British Journal of Pharmacology Mar 2012Emesis is a multi-system reflex, which is usually investigated using in vivo models. The aim of the study is to compare the response induced by emetic compounds across... (Comparative Study)
Comparative Study Review
BACKGROUND AND PURPOSE
Emesis is a multi-system reflex, which is usually investigated using in vivo models. The aim of the study is to compare the response induced by emetic compounds across species and investigate whether dogs, ferrets and rats are all similarly predictive of humans.
EXPERIMENTAL APPROACH
A systematic review was carried out and relevant publications were identified from PubMed. The search was restricted to four species (human, dog, ferret, rat) and ten compounds representative of various mechanisms of emesis induction (apomorphine, cisplatin, cholecystokinin octapeptide, copper sulphate, cyclophosphamide, ipecacuanha, lithium chloride, morphine, nicotine, rolipram).
KEY RESULTS
1046 publications were reviewed, and 311 were included, the main reason for exclusion was the lack of quantitative data. Emetic or pica data were extracted as incidence, intensity or latency. All three animal species identified emetic liability but interspecies differences for dose sensitivity were detected.
CONCLUSIONS AND IMPLICATION
These results suggest that emetic liability can be reliably identified in a common laboratory species such as the rat. However, to evaluate the characteristics of the emetic response, no animal species is a universal predictor of emetic liability and the choice of species should be an informed decision based on the type of compound investigated. Limitations relating to the conduct and reporting of emesis studies were identified, the main ones being the lack of comparable outcome measures between human and animal data, and the limited availability of human data in the public domain.
Topics: Animals; Dogs; Emetics; Ferrets; Humans; Rats; Vomiting
PubMed: 21913900
DOI: 10.1111/j.1476-5381.2011.01669.x -
BioMed Research International 2013There is a growing evidence that neuropeptides may be involved in the pathophysiology of suicidal behavior. A critical review of the literature was conducted to... (Meta-Analysis)
Meta-Analysis Review
There is a growing evidence that neuropeptides may be involved in the pathophysiology of suicidal behavior. A critical review of the literature was conducted to investigate the association between neuropeptides and suicidal behavior. Only articles from peer-reviewed journals were selected for the inclusion in the present review. Twenty-six articles were assessed for eligibility but only 22 studies were included. Most studies have documented an association between suicidality and some neuropeptides such as corticotropin-releasing factor (CRF), VGF, cholecystokinin, substance P, and neuropeptide Y (NPY), which have been demonstrated to act as key neuromodulators of emotional processing. Significant differences in neuropeptides levels have been found in those who have attempted or completed suicide compared with healthy controls or those dying from other causes. Despite cross-sectional associations between neuropeptides levels and suicidal behavior, causality may not be inferred. The implications of the mentioned studies were discussed in this review paper.
Topics: Arginine Vasopressin; Corticotropin-Releasing Hormone; Dynorphins; Galanin; Humans; Intracellular Signaling Peptides and Proteins; Neuropeptides; Orexins; Oxytocin; Substance P; Suicide
PubMed: 23986909
DOI: 10.1155/2013/687575 -
The Cochrane Database of Systematic... Jul 2012Pharmacotherapy remains an important modality for the treatment of neuropathic pain. However, as monotherapy current drugs are associated with limited efficacy and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Pharmacotherapy remains an important modality for the treatment of neuropathic pain. However, as monotherapy current drugs are associated with limited efficacy and dose-related side effects. Combining two or more different drugs may improve analgesic efficacy and, in some situations, reduce overall side effects (e.g. if synergistic interactions allow for dose reductions of combined drugs).
OBJECTIVES
This review evaluated the efficacy, tolerability and safety of various drug combinations for the treatment of neuropathic pain.
SEARCH METHODS
We identified randomised controlled trials (RCTs) of various drug combinations for neuropathic pain from CENTRAL, MEDLINE, EMBASE and handsearches of other reviews and trial registries. The most recent search was performed on 9 April 2012.
SELECTION CRITERIA
Double-blind, randomised studies comparing combinations of two or more drugs (systemic or topical) to placebo and/or at least one other comparator for the treatment of neuropathic pain.
DATA COLLECTION AND ANALYSIS
Data extracted from each study included: proportion of participants a) reporting ≥ 30% pain reduction from baseline OR ≥ moderate pain relief OR ≥ moderate global improvement; b) dropping out of the trial due to treatment-emergent adverse effects; c) reporting each specific adverse effect (e.g. sedation, dizziness) of ≥ moderate severity. The primary comparison of interest was between study drug(s) and one or both single-agent comparators. We combined studies if they evaluated the same drug class combination at roughly similar doses and durations of treatment. We used RevMan 5 to analyse data for binary outcomes.
MAIN RESULTS
We identified 21 eligible studies: four (578 participants) evaluated the combination of an opioid with gabapentin or pregabalin; two (77 participants) evaluated an opioid with a tricyclic antidepressant; one (56 participants) of gabapentin and nortriptyline; one (120 participants) of gabapentin and alpha-lipoic acid, three (90 participants) of fluphenazine with a tricyclic antidepressant; three (90 participants) of an N-methyl-D-aspartate (NMDA) blocker with an agent from a different drug class; five (604 participants) of various topical medications; one (313 participants) of tramadol with acetaminophen; and another one (44 participants) of a cholecystokinin blocker (L-365,260) with morphine. The majority of combinations evaluated to date involve drugs, each of which share some element of central nervous system (CNS) depression (e.g. sedation, cognitive dysfunction). This aspect of side effect overlap between the combined agents was often reflected in similar or higher dropout rates for the combination and may thus substantially limit the utility of such drug combinations. Meta-analysis was possible for only one comparison of only one combination, i.e. gabapentin + opioid versus gabapentin alone. This meta-analysis involving 386 participants from two studies demonstrated modest, yet statistically significant, superiority of a gabapentin + opioid combination over gabapentin alone. However, this combination also produced significantly more frequent side effect-related trial dropouts compared to gabapentin alone.
AUTHORS' CONCLUSIONS
Multiple, good-quality studies demonstrate superior efficacy of two-drug combinations. However, the number of available studies for any one specific combination, as well as other study factors (e.g. limited trial size and duration), preclude the recommendation of any one specific drug combination for neuropathic pain. Demonstration of combination benefits by several studies together with reports of widespread clinical polypharmacy for neuropathic pain surely provide a rationale for additional future rigorous evaluations. In order to properly identify specific drug combinations which provide superior efficacy and/or safety, we recommend that future neuropathic pain studies of two-drug combinations include comparisons with placebo and both single-agent components. Given the apparent adverse impact of combining agents with similar adverse effect profiles (e.g. CNS depression), the anticipated development and availability of non-sedating neuropathic pain agents could lead to the identification of more favourable analgesic drug combinations in which side effects are not compounded.
Topics: Acetaminophen; Adult; Amines; Analgesics; Antidepressive Agents, Tricyclic; Benzodiazepinones; Cyclohexanecarboxylic Acids; Drug Therapy, Combination; Gabapentin; Humans; Morphine; N-Methylaspartate; Neuralgia; Nortriptyline; Phenylurea Compounds; Pregabalin; Thioctic Acid; Tramadol; gamma-Aminobutyric Acid
PubMed: 22786518
DOI: 10.1002/14651858.CD008943.pub2 -
PloS One 2016The effects of non-nutritive sweeteners (NNS) on glucose metabolism and appetite regulating hormones are not clear. There is an ongoing debate concerning NNS use and... (Review)
Review
Effects of the Non-Nutritive Sweeteners on Glucose Metabolism and Appetite Regulating Hormones: Systematic Review of Observational Prospective Studies and Clinical Trials.
BACKGROUND
The effects of non-nutritive sweeteners (NNS) on glucose metabolism and appetite regulating hormones are not clear. There is an ongoing debate concerning NNS use and deleterious changes in metabolism.
OBJECTIVES
The aim of this review is to analyze the scientific available evidence regarding the effects of NNS on glucose metabolism and appetite regulating hormones.
DATA SOURCES AND STUDY ELIGIBILITY CRITERIA
We identified human observational studies evaluating the relation between NNS consumption and obesity, diabetes, and metabolic syndrome, in addition to clinical trials evaluating the effects of NNS in glucose metabolism and appetite regulating hormones.
RESULTS
Fourteen observational studies evaluating the association between NNS consumption and the development of metabolic diseases and twenty-eight clinical trials studying the effects of NNS on metabolism were included. Finally, two meta-analyses evaluating the association between the consumption of NNS-containing beverages and the development of type 2 diabetes were identified.
CONCLUSIONS
Some observational studies suggest an association between NNS consumption and development of metabolic diseases; however, adiposity is a confounder frequently found in observational studies. The effects of the NNS on glucose metabolism are not clear. The results of the identified clinical trials are contradictory and are not comparable because of the major existing differences between them. Studies evaluating specific NNS, with an adequate sample size, including a homogeneous study group, identifying significant comorbidities, with an appropriate control group, with an appropriate exposure time, and considering adjustment for confounder variables such as adiposity are needed.
Topics: Carbonated Beverages; Cholecystokinin; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Ghrelin; Glucose; Humans; Non-Nutritive Sweeteners; Observational Studies as Topic; Peptide YY; Prospective Studies
PubMed: 27537496
DOI: 10.1371/journal.pone.0161264 -
Alimentary Pharmacology & Therapeutics Jul 2003Patients with suspected functional biliary pain often undergo cholecystectomy if a decreased gall-bladder ejection fraction (GBEF <35%) is demonstrated by... (Meta-Analysis)
Meta-Analysis Review
Systematic review and meta-analysis: does gall-bladder ejection fraction on cholecystokinin cholescintigraphy predict outcome after cholecystectomy in suspected functional biliary pain?
BACKGROUND
Patients with suspected functional biliary pain often undergo cholecystectomy if a decreased gall-bladder ejection fraction (GBEF <35%) is demonstrated by cholecystokinin cholescintigraphy. However, the validity of GBEF in predicting which patients will have symptomatic relief following cholecystectomy is unclear.
AIM
To determine whether patients with suspected functional biliary pain with decreased GBEF have a better symptomatic outcome after cholecystectomy than those with normal GBEF.
METHODS
Systematic review and meta-analysis of the published literature through MEDLINE and EMBASE databases.
RESULTS
We included nine studies with a total of 974 patients with suspected functional biliary pain; 362 patients underwent cholecystectomy. Most studies assessed outcome by direct patient interview. Mean ages across the studies ranged from 35 to 47 years; 78% of all patients were female. Mean duration of follow-up after surgery ranged from 1 to 2.5 years. After cholecystectomy, 94% of the patients with reduced GBEF had a positive outcome compared to 85% among those with normal GBEF. The pooled Mantel-Haenszel odds ratio for positive outcome was 1.37 (95% confidence interval 0.56-3.34), P=0.56.
CONCLUSION
These data do not support the use of GBEF to select patients with suspected functional biliary pain for cholecystectomy. Prospective randomized trials are required if this practice is to be evidence-based.
Topics: Cholecystectomy; Cholecystokinin; Gallbladder; Gallbladder Diseases; Gallbladder Emptying; Humans; Pain; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Disofenin; Treatment Outcome
PubMed: 12869076
DOI: 10.1046/j.1365-2036.2003.01654.x