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1.
Osteoarthritis Cartilage ; 30(5): 724-734, 2022 05.
Article in English | MEDLINE | ID: mdl-35227892

ABSTRACT

OBJECTIVES: To investigate how ANP32A, previously linked to the antioxidant response, regulates Wnt signaling as unraveled by transcriptome analysis of Anp32a-deficient mouse articular cartilage, and its implications for osteoarthritis (OA) and diseases beyond the joint. METHODS: Anp32a knockdown chondrogenic ATDC5 cells were cultured in micromasses. Wnt target genes, differentiation markers and matrix deposition were quantified. Wnt target genes were determined in articular cartilage from Anp32a-deficient mice and primary human articular chondrocytes upon ANP32A silencing, using qPCR, luciferase assays and immunohistochemistry. Co-immunoprecipitation, immunofluorescence and chromatin-immunoprecipitation quantitative PCR probed the molecular mechanism via which ANP32A regulates Wnt signaling. Anp32a-deficient mice were subjected to the destabilization of the medial meniscus (DMM) OA model and treated with a Wnt inhibitor and an antioxidant. Severity of OA was assessed by cartilage damage and osteophyte formation. Human Protein Atlas data analysis identified additional organs where ANP32A may regulate Wnt signaling. Wnt target genes were determined in heart and hippocampus from Anp32a-deficient mice, and cardiac hypertrophy and fibrosis quantified. RESULTS: Anp32a loss triggered Wnt signaling hyper-activation in articular cartilage. Mechanistically, ANP32A inhibited target gene expression via histone acetylation masking. Wnt antagonist treatment reduced OA severity in Anp32a-deficient mice by preventing osteophyte formation but not cartilage degradation, contrasting with antioxidant treatment. Dual therapy ameliorated more OA features than individual treatments. Anp32a-deficient mice also showed Wnt hyper-activation in the heart, potentially explaining the cardiac hypertrophy phenotype found. CONCLUSIONS: ANP32A is a novel translationally relevant repressor of Wnt signaling impacting osteoarthritis and cardiac disease.


Subject(s)
Cartilage, Articular , Heart Diseases , Osteoarthritis , Osteophyte , Animals , Antioxidants/metabolism , Cardiomegaly/metabolism , Cartilage, Articular/metabolism , Chondrocytes/metabolism , Heart Diseases/metabolism , Mice , Osteoarthritis/genetics , Osteoarthritis/metabolism , Osteophyte/metabolism , Wnt Signaling Pathway/physiology
2.
Tijdschr Psychiatr ; 63(4): 276-282, 2021.
Article in Dutch | MEDLINE | ID: mdl-33913143

ABSTRACT

BACKGROUND: International consensus states that seclusion and restraint should only be applied as briefly and as little as possible. However, audits by the Care Inspectorate show that this is not always the case in Flemish mental health care (MHC). AIM: To describe the development of a multidisciplinary guideline for the prevention and application of seclusion and restraint in inpatient MHC, underpinned by both clinical-scientific and legal evidence. METHOD: The GRADE method formed the basis for the development of the guideline. To integrate both types of evidence, two research phases were added. This article provides an overview of the challenges involved in implementing this interdisciplinary method. RESULTS: There are gaps in both clinical-scientific and legal evidence. Nevertheless, the study resulted in a comprehensive guideline because we underpinned the recommendations with practice- and experience-based expertise of the Flemish stakeholders, and integrated the clinical-scientific and legal evidence. CONCLUSION: Focus on implementation research and a clear legal framework for Flanders are necessary to safeguard the (human) rights of MHC users, also in the event of aggression and escalation.


Subject(s)
Guidelines as Topic , Mental Disorders/therapy , Patient Isolation , Restraint, Physical , Aggression , Humans , Mental Disorders/psychology , Netherlands
3.
Clin Rehabil ; 31(9): 1215-1225, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28786335

ABSTRACT

OBJECTIVE: To explore the reliability and feasibility of electronic visual analogue scales in people with multiple sclerosis (MS) and healthy individuals. DESIGN: Cross-sectional observational study Setting: Clinical setting Subjects: Convenience sample of 52 people with MS and 52 matched healthy controls Interventions: NA Main measures: Participants scored 15 statements assessing fatigue, pain, anxiety and quality of life on an electronic visual analogue scale (eVAS), either using a smartphone or a tablet (randomly allocated). To check for test-retest reliability, statements were administered in two separate randomly ordered groups. Subjects completed a feasibility questionnaire. RESULTS: Mean (SD) eVAS scores ranged from 35 (28.1) to 80 (22.1) in MS group, and from 57 (28.0) to 86 (13.2) in controls. Intra Class Correlations ranged from 0.73 to 0.95 in MS sample; 0.61 to 0.92 in controls. For most statements, Bland-Altman plots indicated no systematic error, but relatively large random error of the eVAS scores (exceeding 20mm). Considerable ceiling effects (i.e. better health) were found in healthy controls. Similar reliability was found among smartphone or tablet, different demographic groups and the experience-groups. CONCLUSION: Electronic visual analogue scales are reliable and useful for people with MS to register fatigue, pain, anxiety and quality of life.


Subject(s)
Anxiety Disorders/diagnosis , Fatigue/diagnosis , Multiple Sclerosis/psychology , Pain/diagnosis , Quality of Life , Visual Analog Scale , Adult , Anxiety Disorders/etiology , Cross-Sectional Studies , Fatigue/etiology , Feasibility Studies , Female , Humans , Male , Middle Aged , Multiple Sclerosis/complications , Pain/etiology , Reproducibility of Results , Smartphone
4.
Endocr Dev ; 25: 41-8, 2013.
Article in English | MEDLINE | ID: mdl-23652390

ABSTRACT

Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor (GHS-R) which was identified in the pituitary gland and is now named the ghrelin receptor. However, the peptide is most abundant in the stomach and ghrelin receptors are present in all major organ systems and tissues. Ghrelin forms with motilin, a new gut peptide family and the sequence similarities of peptides and receptors suggest they evolved by gene duplication. Nevertheless, no cross-reactivity exits between both peptides. Ghrelin shares with motilin motor effects in the gut, in particular gastric emptying and the induction of the migrating motor complex, but ghrelin also affects gastric acid secretion, offers gastroprotection and may modulate intestinal inflammation. The effects of ghrelin result from the activation of central, vagal and enteric neural receptors and receptors on immune cells. Ghrelin agonists have been developed for the treatment of hypomotility disorders and the peptidomimetic TZP-102 is in phase 2 clinical trials for diabetic gastroparesis.


Subject(s)
Gastrointestinal Tract/metabolism , Ghrelin/metabolism , Animals , Cross Reactions , Cytoprotection/drug effects , Cytoprotection/physiology , Gastroenteritis/etiology , Gastroenteritis/prevention & control , Gastrointestinal Motility/drug effects , Gastrointestinal Motility/physiology , Gastrointestinal Tract/drug effects , Gastrointestinal Tract/physiology , Ghrelin/agonists , Ghrelin/pharmacology , Humans , Motilin/immunology , Motilin/metabolism , Motilin/physiology , Peptic Ulcer/etiology , Peptic Ulcer/prevention & control , Receptors, Ghrelin/immunology , Receptors, Ghrelin/metabolism
5.
J Bone Joint Surg Br ; 94(9): 1271-6, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22933502

ABSTRACT

Obtaining a balanced flexion gap with correct femoral component rotation is one of the prerequisites for a successful outcome after total knee replacement (TKR). Different techniques for achieving this have been described. In this study we prospectively compared gap-balancing versus measured resection in terms of reliability and accuracy for femoral component rotation in 96 primary TKRs performed in 96 patients using the Journey system. In 48 patients (18 men and 30 women) with a mean age of 65 years (45 to 85) a tensor device was used to determine rotation. In the second group of 48 patients (14 men and 34 women) with a mean age of 64 years (41 to 86), an 'adapted' measured resection technique was used, taking into account the native rotational geometry of the femur as measured on a pre-operative CT scan. Both groups systematically reproduced a similar external rotation of the femoral component relative to the surgical transepicondylar axis: 2.4° (SD 2.5) in the gap-balancing group and 1.7° (SD 2.1) in the measured resection group (p = 0.134). Both gap-balancing and adapted measured resection techniques proved equally reliable and accurate in determining femoral component rotation after TKR. There was a tendency towards more external rotation in the gap-balancing group, but this difference was not statistically significant (p = 0.134). The number of outliers for our 'adapted' measured resection technique was much lower than reported in the literature.


Subject(s)
Arthroplasty, Replacement, Knee/methods , Femur/diagnostic imaging , Knee Joint/diagnostic imaging , Knee Joint/physiopathology , Leg Bones/diagnostic imaging , Osteoarthritis, Knee/surgery , Aged , Aged, 80 and over , Body Weights and Measures/methods , Calibration , Female , Humans , Male , Middle Aged , Prospective Studies , Radiography , Reproducibility of Results , Rotation
6.
IEEE Trans Vis Comput Graph ; 17(5): 612-25, 2011 May.
Article in English | MEDLINE | ID: mdl-20421681

ABSTRACT

Abstract-Any sufficiently smooth, positive, real-valued function ψ : S(2) → K+ on a sphere S(2) can be expanded by a Laplace expansion into a sum of spherical harmonics. Given the Laplace expansion coefficients, we provide a CPU and GPU-based algorithm that renders the radial graph of ψ in a fast and efficient way by ray-casting the glyph of ψ in the fragment shader of a GPU. The proposed rendering algorithm has proven highly useful in the visualization of high angular resolution diffusion imaging (HARDI) data. Our implementation of the rendering algorithm can display simultaneously thousands of glyphs depicting the local diffusivity of water. The rendering is fast enough to allow for interactive manipulation of large HARDI data sets.

7.
Neurogastroenterol Motil ; 21(5): 528-33, e8-9, 2009 May.
Article in English | MEDLINE | ID: mdl-19210631

ABSTRACT

Ghrelin increases gastric tone in the fasting state and enhances gastric emptying in gastroparesis. The aims of the study were to evaluate the effect of ghrelin on postprandial gastric tone and on meal-induced satiety in health. Ten healthy volunteers underwent a barostat study on two occasions. After determination of intra-abdominal pressure (minimal distending pressure, MDP), isobaric volume measurement was performed for 90 min at MDP + 2 mmHg. After 20 min, ghrelin (40 microg) or saline was administered i.v. over 30 min in a double-blind-randomized cross-over design, followed 10 min later by a liquid meal (200 mL, 300 kcal). Stepwise isobaric distentions (+2 mmHg per 2 min) were performed 60 min after the meal. Data (mean +/- SEM) were compared using paired Student's t-test and ANOVA. Separately, a satiety drinking test (15 mL min(-1) until satiety score 5) was performed on 10 subjects twice, after treatment with placebo or ghrelin. Ghrelin infusion significantly inhibited gastric accommodation (mean volume increase adjusted means 108.0 +/- 50 vs 23.0 +/- 49 mL, P = 0.03, ANCOVA with the premeal postinfusion volume as covariate) and reduced postprandial gastric volumes (197.2 +/- 24.6 vs 353.5 +/- 50.0 mL, P = 0.01). Pressures inducing perception or discomfort during postprandial gastric distentions were not altered. During satiety testing, ghrelin did not alter nutrient volume ingested till maximal satiety (637.5 +/- 70.9 vs 637.5 +/- 56.2 mL, ns). Ghrelin administered during the meal significantly inhibits gastric accommodation in health, but this is not associated with early satiation.


Subject(s)
Gastric Emptying/drug effects , Ghrelin/pharmacology , Reflex/drug effects , Satiety Response/drug effects , Stomach , Adult , Cross-Over Studies , Double-Blind Method , Eating , Female , Gastric Emptying/physiology , Humans , Male , Muscle Contraction/drug effects , Muscle Contraction/physiology , Postprandial Period/drug effects , Pressure , Random Allocation , Reflex/physiology , Satiety Response/physiology , Sensation/drug effects , Stomach/drug effects , Stomach/physiology
8.
Neurogastroenterol Motil ; 21(1): 59-70, 2009 Jan.
Article in English | MEDLINE | ID: mdl-18823291

ABSTRACT

Ghrelin is an important orexigenic peptide that not only exerts gastroprokinetic but also immunoregulatory effects. This study aimed to assess the role of endogenous and exogenous ghrelin in the pathogenesis of colitis and in the disturbances of gastric emptying and colonic contractility during this process. Dextran sodium sulphate colitis was induced for 5 days in (i) ghrelin(+/+) and ghrelin(-/-) mice and clinical and histological parameters were monitored at days 5, 10 and 26 and (ii) in Naval Medical Research Institute non-inbred Swiss (NMRI) mice treated with ghrelin (100 nmol kg(-1)) twice daily for 5 or 10 days. Neural contractility changes were measured in colonic smooth muscle strips, whereas gastric emptying was measured with the (14)C octanoic acid breath test. Inflammation increased ghrelin plasma levels. Body weight loss, histological damage, myeloperoxidase activity and IL-1beta levels were attenuated in ghrelin(-/-) mice. Whereas absence of ghrelin did not affect changes in colonic contractility, gastric emptying in the acute phase was accelerated in ghrelin(+/+) but not in ghrelin(-/-) mice. In agreement with the studies in ghrelin knockout mice, 10 days treatment of NMRI mice with exogenous ghrelin enhanced the clinical disease activity and promoted infiltration of neutrophils and colonic IL-1beta levels. Unexpectedly, ghrelin treatment decreased excitatory and inhibitory neural responses in the colon of healthy but not of inflamed NMRI mice. Endogenous ghrelin enhances the course of the inflammatory process and is involved in the disturbances of gastric emptying associated with colitis. Treatment with exogenous ghrelin aggravates colitis, thereby limiting the potential therapeutic properties of ghrelin during intestinal inflammation.


Subject(s)
Colitis/physiopathology , Ghrelin/metabolism , Animals , Colitis/chemically induced , Colitis/pathology , Dextran Sulfate/toxicity , Gastric Emptying/drug effects , Gastric Emptying/physiology , Ghrelin/pharmacology , Male , Mice , Mice, Knockout , Muscle Contraction/drug effects , Muscle Contraction/physiology , Muscle, Smooth/drug effects , Muscle, Smooth/physiology
10.
Neurogastroenterol Motil ; 20(7): 818-28, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18312542

ABSTRACT

Decreased gastric expression and function of neuronal nitric oxide synthase (nNOS) has been proposed as a potential mechanism underlying diabetic gastroparesis. As gastric nNOS expression is vagally controlled, these changes might occur secondarily to vagal neuropathy. In addition, it is unclear whether other inhibitory neurotransmitters are also involved. We used the type 1 diabetic BioBreeding (BB)-rat model to study jejunal motor control and nNOS expression, which is independent of the vagus. Jejunal segments were used for in vitro contractility studies, and measurement of nNOS expression after 8 or 16 weeks of diabetes compared with age- and sex-matched controls. Unlike electrical field stimulation and acetylcholine (ACh)-induced contractions, non-adrenergic non-cholinergic (NANC) relaxations were significantly reduced in diabetic rats. In contrast to control rats, NANC relaxations in diabetic rats were N(omega)-nitro-L-arginine methyl ester (L-NAME) insensitive. Jejunal nNOS expression was significantly decreased in diabetic rats. Both in diabetic and in control animals, L-NAME resistant relaxations were sensitive to P(2)-receptor antagonists. In the jejunum of spontaneously diabetic rats, decreased nitric oxide responsiveness and decreased nNOS protein expression occur while purinergic transmission is unaffected. These findings indicate that nitrergic enteric neuropathy may be a primary dysfunction in diabetes, independent from vagal dysfunction.


Subject(s)
Gastrointestinal Diseases , Jejunum/innervation , Myenteric Plexus/pathology , Rats, Inbred BB , Animals , Electric Stimulation , Enzyme Inhibitors/metabolism , Female , Gastrointestinal Diseases/pathology , Gastrointestinal Diseases/physiopathology , Jejunum/anatomy & histology , Male , Muscle Contraction/physiology , Muscle Relaxation/physiology , NG-Nitroarginine Methyl Ester/metabolism , Nitric Oxide Synthase Type I/metabolism , Rats , Ubiquitin Thiolesterase/metabolism
11.
Br J Pharmacol ; 153(7): 1550-7, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18204478

ABSTRACT

BACKGROUND AND PURPOSE: The finding that obestatin, a peptide encoded by the ghrelin gene, opposes ghrelin's stimulatory effect on food intake and gastric emptying has been questioned. The effect of obestatin has been mostly investigated in fasted rodents, a condition associated with high blood levels of ghrelin which may mask the effect of obestatin. We therefore investigated the effect of obestatin on food intake, gastric emptying and gastric contractility in ghrelin knockout mice. EXPERIMENTAL APPROACH: The effect of obestatin on 6-h cumulative food intake was studied in fasted wildtype (ghrelin+/+) and ghrelin knockout (ghrelin-/-) mice. In both genotypes, the effect of obestatin and/or ghrelin was studied in vivo on gastric emptying measured with the (14)C-octanoic acid breath test and in vitro on neural responses elicited by electrical field stimulation (EFS) of fundic smooth muscle strips. KEY RESULTS: Administration of obestatin did not influence fasting-induced hyperphagia or gastric emptying in both genotypes. Injection of ghrelin accelerated gastric emptying in ghrelin+/+ and ghrelin-/- mice but the effect was not reversed by co-injection with obestatin. In fundic strips from ghrelin+/+ and ghrelin-/- mice, ghrelin increased EFS-induced contractions, but obestatin was without effect. However, co-administration with obestatin tended to reduce the excitatory effect of ghrelin in both genotypes. CONCLUSIONS AND IMPLICATIONS: In ghrelin-/- mice, obestatin failed to affect food intake and gastric motility. These results suggest that endogenous ghrelin does not mask the effect of obestatin and confirm that obestatin administered peripherally is not a major regulator of satiety signalling or gut motility.


Subject(s)
Eating/drug effects , Gastric Emptying/drug effects , Ghrelin/pharmacology , Animals , Breath Tests , Caprylates , Cross-Over Studies , Electric Stimulation , Gastric Fundus/drug effects , Gastric Fundus/metabolism , Genotype , Ghrelin/administration & dosage , Ghrelin/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Muscle Contraction/drug effects , Muscle Contraction/physiology , Satiety Response/drug effects , Satiety Response/physiology , Signal Transduction/drug effects , Signal Transduction/physiology
12.
J Vet Pharmacol Ther ; 30(6): 541-9, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17991222

ABSTRACT

The present study examines comparatively the effects of theophylline and its metabolites, 1-methylxanthine (1-MX), 3-methylxanthine (3-MX), 1,3-dimethyluric acid (1,3-DMU) and 1-methyluric acid (1-MU) along the rabbit intestine, and explores the underlying mechanism(s). In the small intestine, theophylline produces atropine- and hexamethonium-sensitive increases in both the amplitude of phasic contractions and the basal tone. All metabolites mimic the theophylline's stimulating effect. In particular, concerning the phasic contractions, all metabolites are more potent than theophylline in the duodenum and jejunum, while in the ileum, only 1-MU is more potent. Regarding the basal tone, the metabolites show, in most cases, higher efficacy in all small intestinal regions, the maximum effects of 3-MX and 1-MU on the duodenum and ileum being double or triple the one of theophylline. In the ascending colon, while lower concentrations of theophylline produce an atropine- and hexamethonium-sensitive increase in the basal tone, higher ones produce a postsynaptic, nonadrenergic noncholinergic (NANC) relaxing effect. 1-MU mimics, in a weaker manner, theophylline's effect, while the other metabolites produce only relaxation, the potency rank of order being 3-MX>1-MX=1,3-DMU>theophylline. It is suggested that the theophylline and its metabolites stimulatory effect involves a cholinergic pathway, while the relaxing one is due to 3('),5(')-cyclic adenosine monophosphate (cAMP) elevation mediated by the theophylline and its metabolites inhibitory action on phosphodiesterases (PDEs).


Subject(s)
Bronchodilator Agents/pharmacology , Colon/drug effects , Intestine, Small/drug effects , Theophylline/pharmacology , Animals , Bronchodilator Agents/administration & dosage , Colon/physiology , Dose-Response Relationship, Drug , Female , Intestine, Small/physiology , Male , Muscle Contraction/drug effects , Muscle Contraction/physiology , Rabbits , Theophylline/administration & dosage
13.
Neurogastroenterol Motil ; 19(3): 211-7, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17300291

ABSTRACT

Obestatin has recently been discovered in the rat stomach. It is encoded by the ghrelin gene and has been claimed to be a functional opponent of ghrelin and to be the natural ligand of the GPR39 receptor. The latter could not be confirmed by Holst et al. (Endocrinology, 2006). Yet, in GPR39 knockout mice, gastric emptying is accelerated. We verified the effects of obestatin on gastric emptying and intestinal contractility in rodents. Gastric emptying was measured with the (14)C octanoic breath test in mice. In vitro, the effect of obestatin was studied on electrically stimulated and non-stimulated strips from the fundus and small intestine of mice and rats. Obestatin (60, 125, 250 nmol kg(-1)) did not affect gastric emptying parameters (T(half) and T(lag)) and did not inhibit the prokinetic effects of ghrelin. Mouse and rat intestinal and fundic smooth muscle strips did not respond to obestatin either in the absence or in the presence of electrical field stimulation. Obestatin (125 nmol kg(-1)) did not inhibit fasting-induced hyperphagia. Our results suggest that peripheral obestatin is not a satiety signal that plays a role in the regulation of gastric emptying and do not support the concept that obestatin is a physiological opponent of ghrelin.


Subject(s)
Gastric Emptying/physiology , Gastrointestinal Motility/physiology , Muscle, Smooth/physiology , Peptide Hormones/metabolism , Animals , Male , Mice , Mice, Inbred C57BL , Muscle Contraction/physiology , Rats , Rats, Wistar
14.
J Voice ; 21(2): 151-6, 2007 Mar.
Article in English | MEDLINE | ID: mdl-16504470

ABSTRACT

SUMMARY: Bilateral (quasi) symmetrical lesions of the anterior third of the vocal folds, commonly called vocal fold nodules (VFNs) are the most frequent vocal fold lesions in childhood caused by vocal abuse and hyperfunction. This study evaluates their long-term genesis with or without surgery and voice therapy. A group of 91 postmutational adolescents (mean age, 16 years), in whom VFNs were diagnosed in childhood, were questioned to analyze the evolution of their complaints. Thirty four of them could be clinically reexamined by means of the European Laryngological Society-protocol, including a complete laryngological investigation and voice assessment. A total of 21% of the questioned group (n=91) had voice complaints persisting into postpubescence with a statistically significant difference (P

Subject(s)
Vocal Cords/pathology , Voice Disorders/pathology , Voice Disorders/physiopathology , Adolescent , Age Factors , Child , Child, Preschool , Disease Progression , Female , Humans , Laryngoscopy/methods , Male , Severity of Illness Index , Voice Disorders/diagnosis , Voice Quality
15.
Science ; 313(5785): 351-4, 2006 Jul 21.
Article in English | MEDLINE | ID: mdl-16857940

ABSTRACT

Despite widespread concern about declines in pollination services, little is known about the patterns of change in most pollinator assemblages. By studying bee and hoverfly assemblages in Britain and the Netherlands, we found evidence of declines (pre-versus post-1980) in local bee diversity in both countries; however, divergent trends were observed in hoverflies. Depending on the assemblage and location, pollinator declines were most frequent in habitat and flower specialists, in univoltine species, and/or in nonmigrants. In conjunction with this evidence, outcrossing plant species that are reliant on the declining pollinators have themselves declined relative to other plant species. Taken together, these findings strongly suggest a causal connection between local extinctions of functionally linked plant and pollinator species.


Subject(s)
Bees , Biodiversity , Diptera , Ecosystem , Plants , Pollen , Animal Migration , Animals , Environment , Flowers , Netherlands , Population Dynamics , United Kingdom
16.
Endocrinology ; 147(6): 2634-42, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16484325

ABSTRACT

Ghrelin is an orexigenic peptide involved in the regulation of energy homeostasis. To investigate the role of ghrelin in the hyperphagia associated with uncontrolled streptozotocin-induced diabetes, food intake was followed in diabetic ghrelin knockout (ghrelin(-/-)) and control wild-type (ghrelin(+/+)) mice and diabetic Naval Medical Research Institute noninbred Swiss mice treated with either saline or the ghrelin receptor antagonist, D-Lys3-GH-releasing peptide-6 (D-Lys3-GHRP-6) for 5 d. In diabetic ghrelin(-/-) mice, hyperphagia was attenuated, and the maximal increase in food intake was 50% lower in mutant than in wild-type mice. The increased food intake observed during the light period (1000-1200 h) in ghrelin(+/+) mice was abolished in mutant mice. Diabetic ghrelin(-/-) mice lost 12.4% more body weight than ghrelin(+/+) mice. In diabetic ghrelin(+/+) mice, but not in ghrelin(-/-) mice, the number of neuropeptide Y (NPY)-immunoreactive neurons was significantly increased. Diabetic Naval Medical Research Institute noninbred Swiss mice were hyperphagic and had increased plasma ghrelin levels. Treatment with D-Lys3-GHRP-6 reduced daily food intake by 23% and reversed the increased food intake observed during the light period. The change in the number of NPY- (2.4-fold increase) and alpha-MSH (1.7-fold decrease)-immunoreactive hypothalamic neurons induced by diabetes was normalized by D-Lys3-GHRP-6 treatment. Our results suggest that enhanced NPY and reduced alpha-MSH expression are secondary to the release of ghrelin, which should be considered the underlying trigger of hyperphagia associated with uncontrolled diabetes.


Subject(s)
Diabetes Mellitus, Experimental/complications , Hyperphagia/etiology , Peptide Hormones/physiology , Animals , Arcuate Nucleus of Hypothalamus/physiology , Blood Glucose/analysis , Body Weight , Ghrelin , Glucagon/blood , Male , Mice , Mice, Inbred C57BL , Neuropeptide Y/analysis , Neuropeptide Y/physiology , Oligopeptides/pharmacology , Peptide Hormones/blood , Streptozocin , alpha-MSH/analysis
17.
Gut ; 55(3): 327-33, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16216827

ABSTRACT

BACKGROUND: Recent studies in animals have shown that ghrelin stimulates upper gastrointestinal motility through the vagus and enteric nervous system. The aim of the present study therefore was to simultaneously investigate the effect of administration of ghrelin on upper gastrointestinal motility and to elucidate its mode of action by measuring plasma levels of gastrointestinal hormones in humans. MATERIALS AND METHODS: Nine healthy volunteers (four males; aged 22-35 years) underwent combined antroduodenal manometry and proximal stomach barostat study on two separate occasions at least one week apart. Twenty minutes after the occurrence of phase III of the migrating motor complex (MMC), saline or ghrelin 40 mug was administered intravenously over 30 minutes in a double blind, randomised, crossover fashion. Ghrelin, motilin, pancreatic polypeptide, glucagon, and somatostatin were measured by radioimmunoassay in blood samples obtained at 15-30 minute intervals. The influence of ghrelin or saline on MMC phases, hormone levels, and intraballoon volume was compared using paired t test, ANOVA, and chi(2) testing. RESULTS: Spontaneous phase III occurred in all subjects, with a gastric origin in four. Administration of ghrelin induced a premature phase III (12 (3) minutes, p<0.001; gastric origin in nine, p<0.05), compared with saline (95 (13) minutes, gastric origin in two). Intraballoon volumes before infusion were similar (135 (13) v 119 (13) ml; NS) but ghrelin induced a longlasting decrease in intraballoon volume (184 (31) v 126 (21) ml in the first 60 minutes; p<0.05). Administration of ghrelin increased plasma levels of pancreatic polypeptide and ghrelin but motilin, somatostatin, and glucagon levels were not altered. CONCLUSIONS: In humans, administration of ghrelin induces a premature gastric phase III of the MMC, which is not mediated through release of motilin. This is accompanied by prolonged increased tone of the proximal stomach.


Subject(s)
Gastrointestinal Motility/drug effects , Peptide Hormones/pharmacology , Adult , Cross-Over Studies , Double-Blind Method , Female , Gastrointestinal Hormones/blood , Gastrointestinal Motility/physiology , Ghrelin , Humans , Male , Manometry , Pancreatic Polypeptide/blood , Peptide Hormones/blood
19.
J Pharmacol Exp Ther ; 316(1): 431-9, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16203827

ABSTRACT

To elucidate the role of endogenous ghrelin in the regulation of energy homeostasis and gastric emptying, ghrelin knockout mice (ghrelin(-/-)) were generated. Body weight, food intake, respiratory quotient, and heat production (indirect calorimetry), and gastric emptying ((14)C breath test) were compared between ghrelin(+/+) and ghrelin(-/-) mice. In both strains, the effect of exogenous ghrelin on gastric emptying and food intake was determined. Ghrelin(-/-) mice showed some subtle phenotypic changes. Body weight gain and 24-h food intake were not affected, but interruption of the normal light/dark cycle triggered additional food intake in old ghrelin(+/+) but not in ghrelin(-/-) mice. Exogenous ghrelin increased food intake in both genotypes with a bell-shaped dose-response curve that was shifted to the left in ghrelin(-/-) mice. During the dark period, young ghrelin(-/-) mice had a lower respiratory quotient, whereas their heat production was higher than that of the wild-type littermates, inferring a leaner body composition of the ghrelin(-/-) mice. Absence of ghrelin did not affect gastric emptying, and the bell-shaped dose-response curves of the acceleration of gastric emptying by exogenous ghrelin were not shifted between both strains. In conclusion, ghrelin is not an essential regulator of food intake and gastric emptying, but its loss may be compensated by other redundant inputs. In old mice, meal initiation triggered by the light/dark cue may be related to ghrelin. In young animals, ghrelin seems to be involved in the selection of energy stores and in the partitioning of metabolizable energy between storage and dissipation as heat.


Subject(s)
Energy Metabolism/genetics , Gastric Emptying/genetics , Homeostasis/genetics , Peptide Hormones/genetics , Peptide Hormones/physiology , Aging/physiology , Animals , Body Temperature Regulation/genetics , Body Temperature Regulation/physiology , Body Weight/genetics , Body Weight/physiology , Breath Tests , Calorimetry, Differential Scanning , Caprylates , Eating/drug effects , Eating/genetics , Eating/physiology , Energy Metabolism/physiology , Gastric Emptying/physiology , Gastrointestinal Motility/genetics , Gastrointestinal Motility/physiology , Ghrelin , Homeostasis/physiology , Immunohistochemistry , Mice , Mice, Knockout , Oxygen Consumption/genetics , Oxygen Consumption/physiology , Peptide Hormones/pharmacology , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Receptors, Ghrelin
20.
Aliment Pharmacol Ther ; 22(9): 847-53, 2005 Nov 01.
Article in English | MEDLINE | ID: mdl-16225494

ABSTRACT

BACKGROUND: Ghrelin, the endogenous ligand of the growth hormone secretagogue receptor, is released from the stomach. Animal studies suggest that ghrelin stimulates gastrointestinal motor activity. AIM: To investigate the influence of ghrelin on gastric emptying rate and meal-related symptoms in idiopathic gastroparesis. METHODS: In six patients with idiopathic gastroparesis, a breath test was used to measure gastric emptying rates (t(1/2)) for solids and liquids after administration of saline or ghrelin 40 microg/30 min in a double-blind, randomized fashion. At each breath sampling, the patient was asked to grade the intensity of six different symptoms (epigastric pain, bloating, postprandial fullness, nausea, belching and epigastric burning) and these were added to obtain meal-related symptom severity score. RESULTS: Ghrelin significantly enhanced liquid emptying (t(1/2): 86 +/- 7 vs. 53 +/- 6 min, P = 0.02) and tended to enhance solid emptying (144 +/- 45 vs. 98 +/- 15 min, P = 0.06). Ghrelin pre-treatment significantly decreased cumulative meal-related symptom score (196 +/- 30 vs. 136 +/- 23, P = 0.04) and individual scores for fullness (55 +/- 8 vs. 39 +/- 8, P = 0.02), and for pain (40 +/- 8 vs. 16 +/- 5, P < 0.05). CONCLUSIONS: In idiopathic gastroparesis, administration of ghrelin enhances gastric emptying and improves meal-related symptoms. These observations suggest a potential for ghrelin receptor agonists in the treatment of gastroparesis.


Subject(s)
Gastric Emptying/drug effects , Gastroparesis/drug therapy , Human Growth Hormone/administration & dosage , Peptide Hormones/administration & dosage , Breath Tests/methods , Cross-Over Studies , Double-Blind Method , Dyspepsia/etiology , Dyspepsia/physiopathology , Female , Gastrointestinal Agents/administration & dosage , Gastroparesis/complications , Gastroparesis/physiopathology , Ghrelin , Humans , Infusions, Intravenous , Male , Middle Aged , Pain Measurement , Postprandial Period , Stomach/physiopathology , Treatment Outcome
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