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Abstract
In this issue of Neurogastroenterology and Motility we find three new articles on different aspects of ghrelin, dealing with physiological and pathophysiological actions of the peptide. For the reader this is food for thoughts: Does this peptide do everything? Ghrelin is a gut peptide hormone well established to stimulate motility throughout most parts of the gastrointestinal (GI) tract and appetite. Ghrelin has been linked to various GI regulatory mechanisms, the most evident being hunger, over-eating and obesity. In this setting ghrelin has been studied under physiological conditions converging on obesity as a pathophysiological process where the peptide has been employed as an interesting tool for studying the development of obesity. With a widespread distribution of ghrelin receptors on various immune cells, it has been assumed that ghrelin also possesses immunoregulatory properties, thus also being of interest in intestinal inflammation research. Anti-inflammatory effects of exogenous ghrelin have been claimed in experimental colitis in mice. Further studies on this concept using ghrelin gene knock-out mice, however, show an increased inflammatory activity in experimental colitis in wild-type mice pointing to ghrelin as an enhancer of the inflammatory course of the disease. Taken together, recent studies on ghrelin indicate that the peptide is not only a regulatory agent in pathophysiological processes, but also participates in pathological disease conditions with actions that seem to even involve genetic mechanisms.
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Hellström PM, Hein J, Bytzer P, Björnssön E, Kristensen J, Schambye H. Clinical trial: the glucagon-like peptide-1 analogue ROSE-010 for management of acute pain in patients with irritable bowel syndrome: a randomized, placebo-controlled, double-blind study. Aliment Pharmacol Ther 2009; 29:198-206. [PMID: 18945254 DOI: 10.1111/j.1365-2036.2008.03870.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND There is currently no treatment available to manage acute pain attacks in IBS patients regardless of subtype. AIMS To evaluate efficacy and safety of the GLP-1 analogue ROSE-010 in patients with irritable bowel syndrome (IBS) through a randomized, double-blind, placebo-controlled study. METHODS Eligible patients (n = 166) meeting Rome II criteria were randomly assigned to receive single subcutaneous injections of ROSE-010 100 microg, 300 microg and placebo in a cross-over design. Safety was assessed from spontaneously reported adverse events and measurement of vital signs. Patient-rated pain relief and intensity were measured on a 100-mm visual analogue scale. The primary efficacy variable was proportion of patients with >50% maximum total pain relief response from 10 to 60 min after treatment. Secondary endpoints included the maximum summed pain intensity difference, time to meaningful pain relief and patient ratings of satisfaction with treatment. RESULTS Twice as many patients were responders in the primary efficacy endpoint after both ROSE-010 injections compared to placebo (24%P = 0.011, 23%P = 0.005, and 12% after 300 microg, 100 microg and placebo injections, respectively). Similar results were obtained for the proportion of patients with total pain intensity response. Times to meaningful and total pain relief were shorter for both doses of ROSE-010 compared with placebo. Compared with placebo, more patients (P < 0.05) were satisfied with ROSE-010 and considered ROSE-010 better than previous IBS medications used. CONCLUSION ROSE-010 was well tolerated and provided fast and effective relief of acute pain attacks on demand in IBS patients.
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Rudholm T, Wallin B, Theodorsson E, Näslund E, Hellström PM. Release of regulatory gut peptides somatostatin, neurotensin and vasoactive intestinal peptide by acid and hyperosmolal solutions in the intestine in conscious rats. ACTA ACUST UNITED AC 2008; 152:8-12. [PMID: 18992283 DOI: 10.1016/j.regpep.2008.10.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Accepted: 10/01/2008] [Indexed: 12/15/2022]
Abstract
The impact of exposure of the intestinal mucosa to acid and hyperosmolal solutions on the release of the inhibitory gut peptides somatostatin (SOM), neurotensin (NT) and vasoactive intestinal peptide (VIP) was studied in conscious rats during pentagastrin-stimulated gastric acid secretion. The animals were equipped with a chronic gastric fistula to measure acid secretion and a jejunal Thiry-Vella loop for intestinal challenge with saline, hydrochloric acid (HCl, 200 mmol L(-1)) or hyperosmolal polyethylene glycol (PEG, 1200 mOsm kg(-1)). Gut peptide concentrations were measured in intestinal perfusates, and in plasma samples collected during stimulated acid secretion, and at the end of experiments with luminal challenge of the loops. After pentagastrin-stimulation acid secretion was dose-dependently inhibited by intravenous administration of the gastrin receptor antagonist gastrazole, as well as ranitidine and esomeprazole by maximally 73+/-10%; 95+/-3%; 90+/-10%, respectively. Acid perfusion of the Thiry-Vella loop caused a prominent release of SOM both to the lumen (from 7.2+/-5.0 to 1279+/-580 pmol L(-1)) and to the circulation (from 18+/-5.2 to 51+/-9.0 pmol L(-1)) simultaneously with an inhibition of gastric acid secretion. The release of NT and VIP was not affected to the same extent. PEG perfusion of the loop caused a release of SOM as well as NT and VIP, but less. Simultaneously acid secretion was slightly decreased. In conclusion, intestinal perfusion with acid or hyperosmolal solutions mainly releases SOM, which seems to exert a major inhibitory action in the gut, as shown by inhibition of acid secretion. The other peptides NT and VIP also participate in this action but to a much lesser degree. The operative pathways of these gut peptides hence involve both endocrine (SOM) and paracrine actions (SOM, NT, VIP) in order to exert inhibitory functions on the stomach. The inhibitory action of gastrazole, was in a similar range as that of SOM implying that physiological acid-induced inhibition of gastric acid may primarily be exerted through inhibition of gastrin endocrine secretion.
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Gustafsson UO, Nygren J, Thorell A, Soop M, Hellström PM, Ljungqvist O, Hagström-Toft E. Pre-operative carbohydrate loading may be used in type 2 diabetes patients. Acta Anaesthesiol Scand 2008; 52:946-51. [PMID: 18331374 DOI: 10.1111/j.1399-6576.2008.01599.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Post-operative insulin resistance and hyperglycaemia are associated with an impaired outcome after surgery. Pre-operative oral carbohydrate loading (CHO) reduces post-operative insulin resistance with a reduced risk of hyperglycaemia during post-operative nutrition. Insulin-resistant diabetic patients have not been given CHO because the effects on pre-operative glycaemia and gastric emptying are unknown. METHODS Twenty-five patients (45-73 years) with type 2 diabetes [glycated haemoglobin (HbA1c) 6.2 +/- 0.2%, mean +/- SEM] and 10 healthy control subjects (45-72 years) were studied. A carbohydrate-rich drink (400 ml, 12.5%) was given with paracetamol 1.5 g for determination of gastric emptying. RESULTS Peak glucose was higher in diabetic patients than in healthy subjects (13.4 +/- 0.5 vs. 7.6 +/- 0.5 mM; P<0.01) and occurred later after intake (60 vs. 30 min; P<0.01). Glucose concentrations were back to baseline at 180 vs. 120 min in diabetic patients and healthy subjects, respectively (P<0.01). At 120 min, 10.9 +/- 0.7% and 13.3 +/- 1.2% of paracetamol remained in the stomach in diabetic patients and healthy, subjects respectively. Gastric half-emptying time (T50) occurred at 49.8 +/- 2.2 min in diabetics and at 58.6 +/- 3.7 min in healthy subjects (P<0.05). Neither peak glucose, glucose at 180 min, gastric T50, nor retention at 120 min differed between insulin (HbA1c 6.8 +/- 0.7%)- and non-insulin-treated (HbA1c 5.6 +/- 0.4%) patients. CONCLUSIONS Type 2 diabetic patients showed no signs of delayed gastric emptying, suggesting that a carbohydrate-rich drink may be safely administrated 180 min before anaesthesia without risk of hyperglycaemia or aspiration pre-operatively.
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Hellström PM, Näslund E, Edholm T, Schmidt PT, Kristensen J, Theodorsson E, Holst JJ, Efendic S. GLP-1 suppresses gastrointestinal motility and inhibits the migrating motor complex in healthy subjects and patients with irritable bowel syndrome. Neurogastroenterol Motil 2008; 20:649-59. [PMID: 18298441 DOI: 10.1111/j.1365-2982.2007.01079.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is released after food intake to act as an incretin. GLP-1 also inhibits gastric emptying and increases satiety. In rats, GLP-1 inhibits small bowel motility. Our aim was to study the effects of GLP-1 on gastrointestinal motility in healthy subjects and patients with irritable bowel syndrome (IBS). Antro-duodeno-jejunal manometry was carried out during a 4-h control period with saline, followed by a 4-h period with intravenous GLP-1 (healthy: 0.7 and 1.2 pmol kg(-1) min(-1) (n = 16); IBS, 1.2 and 2.5 pmol kg(-1) min(-1) (n = 14). Plasma was analysed for GLP-1 and gut hormones, and gut tissue expression of GLP-1 receptor was studied. In healthy subjects, GLP-1 0.7 pmol kg(-1) min(-1) reduced the migrating motor complexes (MMCs) from a median of 2 (range 2-3) to 0.5 (0-2), and motility index from 4.9 +/- 0.1 to 4.3 +/- 0.3 ln Sigma(mmHg*s min(-1)) in jejunum, while GLP-1 1.2 pmol kg(-1) min(-1) diminished MMCs from 2 (2-3) to 1.5 (1-2.5), and motility index from 5.2 +/- 0.2 to 4.4 +/- 0.2. In IBS patients, GLP-1 1.2 pmol kg(-1) min(-1) reduced the MMCs from 2.5 (2-3.5) to 1 (0-1.5) without affecting motility index. At 2.5 pmol kg(-1) min(-1) GLP-1 decreased MMCs from 2 (1.5-3) to 1 (0.5-1.5), and motility index from 5.2 +/- 0.2 to 4.0 +/- 0.5. Motility responses to GLP-1 were similar in antrum and duodenum. Presence of the GLP-1 receptor in the gut was verified by reverse transcriptase PCR. In conclusion, the gut peptide GLP-1 decreases motility in the antro-duodeno-jejunal region and inhibits the MMC in healthy subjects and IBS patients.
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Jawien J, Bian Z, Sheikine Y, Olofsson PS, Pang Y, Edholm T, Dou Y, Metzger D, Hellström PM, Feil R, Hansson GK. Abrogation of mitochondrial transcription in smooth muscle cells impairs smooth muscle contractility and vascular tone. JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY : AN OFFICIAL JOURNAL OF THE POLISH PHYSIOLOGICAL SOCIETY 2008; 59:239-252. [PMID: 18622043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 04/25/2008] [Indexed: 05/26/2023]
Abstract
BACKGROUND Smooth muscle cells (SMC) constitute the major contractile cell population of blood vessels and inner organs. SMC contraction depends on energy provided by adenosine triphosphate (ATP) catabolism, which can be generated through oxidative phosphorylation in mitochondria or by anaerobic glycolysis. Mitochondrial activity may also modulate smooth muscle tone by biotransformation of vasoactive mediators. Here, we study the role of mitochondrial DNA gene expression for vascular function in vivo. METHODS Since loss of functional mitochondria in SMC may not be compatible with normal development, we generated mice with inducible SMC-specific abrogation of the mitochondrial transcription factor A (Tfam). Deletion of this gene leads to dysfunctional mitochondria and prevents aerobic ATP production in affected cells. RESULTS Invasive blood pressure monitoring in live animals demonstrated that SMC specific Tfam deletion results in lower blood pressure and a defective blood-pressure response to stress, changes that were not compensated by increased heart rate. The contractility to agonists was reduced in arterial and gastric fundus strips from Tfam-deficient mice. Endothelium-dependent relaxation of arterial strips in response to ACh was also blunted. CONCLUSION Our data show that mitochondrial function is needed for normal gastric contraction, vascular tone, and maintenance of normal blood pressure.
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Ljung T, Axelsson LG, Herulf M, Lundberg JO, Hellström PM. Early changes in rectal nitric oxide and mucosal inflammatory mediators in Crohn's colitis in response to infliximab treatment. Aliment Pharmacol Ther 2007; 25:925-32. [PMID: 17402996 DOI: 10.1111/j.1365-2036.2007.03284.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Treatment with tumor necrosis factor-alpha monoclonal antibody (infliximab) reduces clinical activity and intestinal inflammation in Crohn's disease. AIM To study the time-course of the effects of infliximab with reference to mucosal cytokine and inducible nitric oxide synthase expression. METHODS Thirty-two patients with Crohn's disease were treated with single dose infliximab (5 mg/kg). Disease activity was assessed days 1, 3, 7 and 28 using Harvey-Bradshaw index. Rectal nitric oxide levels were determined and rectal biopsies collected before treatment, 1 h after infusion and on days 3, 7 and 28. Immunohistochemical staining against inducible nitric oxide synthase, tumor necrosis factor-alpha, interleukin-1beta and interferon-gamma were performed. RESULTS Clinical response was seen in 14 patients with down-regulation of global immunohistochemistry expression, reaching nadir day 3. Rectal nitric oxide was increased at baseline (3578 +/- 1199 parts per billion, ppb) compared with controls (89 +/- 13 ppb) (P < 0.001). In patients with clinical response, rectal nitric oxide decreased from 3926 +/- 1687 ppb to 1050 +/- 428 ppb day 28 (P < 0.05). CONCLUSIONS Down-regulation of mucosal inflammatory mediators occurs after infliximab. Rectal nitric oxide levels parallel down-regulation of inducible nitric oxide synthase, tumor necrosis factor-alpha, interleukin-1beta and interferon-gamma and may serve as a quantitative biomarker of intestinal inflammation.
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Näslund E, King N, Mansten S, Adner N, Holst JJ, Gutniak M, Hellström PM. Prandial subcutaneous injections of glucagon-like peptide-1 cause weight loss in obese human subjects. Br J Nutr 2007; 91:439-46. [PMID: 15005830 DOI: 10.1079/bjn20031064] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Recombinant glucagon-like peptide-1 (7–36)amide (rGLP-1) was recently shown to cause significant weight loss in type 2 diabetics when administered for 6 weeks as a continuous subcutaneous infusion. The mechanisms responsible for the weight loss are not clarified. In the present study, rGLP-1 was given for 5d by prandial subcutaneous injections (PSI) (76nmol 30min before meals, four times daily; a total of 302·4nmol/24h) or by continuous subcutaneous infusion (CSI) (12·7nmol/h; a total of 304·8nmol/24h). This was performed in nineteen healthy obese subjects (mean age 44·2 (sem 2·5) years; BMI 39·0 (sem 1·2)kg/m2) in a prospective randomised, double-blind, placebo-controlled, cross-over study. Compared with the placebo, rGLP-1 administered as PSI and by CSI generated a 15% reduction in mean food intake per meal (P=0·02) after 5d treatment. A weight loss of 0·55 (sem 0·2) kg (P<0·05) was registered after 5d with PSI of rGLP-1. Gastric emptying rate was reduced during both PSI (P<0·001) and CSI (P<0·05) treatment, but more rapidly and to a greater extent with PSI of rGLP-1. To conclude, a 5d treatment of rGLP-1 at high doses by PSI, but not CSI, promptly slowed gastric emptying as a probable mechanism of action of increased satiety, decreased hunger and, hence, reduced food intake with an ensuing weight loss.
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Bassil AK, Häglund Y, Brown J, Rudholm T, Hellström PM, Näslund E, Lee K, Sanger GJ. Little or no ability of obestatin to interact with ghrelin or modify motility in the rat gastrointestinal tract. Br J Pharmacol 2007; 150:58-64. [PMID: 17128285 PMCID: PMC2013842 DOI: 10.1038/sj.bjp.0706969] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 10/11/2006] [Accepted: 10/16/2006] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Obestatin, encoded by the ghrelin gene may inhibit gastrointestinal (GI) motility. This activity was re-investigated. EXPERIMENTAL APPROACH Rat GI motility was studied in vitro (jejunum contractility and cholinergically-mediated contractions of forestomach evoked by electrical field stimulation; EFS) and in vivo (gastric emptying and intestinal myoelectrical activity). Ghrelin receptor function was studied using a GTPgammaS assay and transfected cells. KEY RESULTS Contractions of the jejunum or forestomach were unaffected by obestatin 100 nM or 0.01-1000 nM, respectively (P>0.05 each; n=4-18). Obestatin (0.1-1 nM) reduced the ability of ghrelin 1 microM to facilitate EFS-evoked contractions of the stomach (increases were 42.7+/-7.8% and 21.2+/-5.0 % in the absence and presence of obestatin 1 nM; P<0.05; n=12); higher concentrations (10-1000 nM) tended to reduce the response to ghrelin but changes were not statistically significant. Similar concentrations of obestatin did not significantly reduce a facilitation of contractions caused by the 5-HT(4) receptor agonist prucalopride, although an inhibitory trend occurred at the higher concentrations (increases were 69.3+/-14.0% and 42.6+/-8.7% in the absence and presence of 1000 nM obestatin; n=10). Obestatin (up to 10 microM) did not modulate recombinant ghrelin receptor function. Ghrelin increased gastric emptying and reduced MMC cycle time; obestatin (1000 and 30,000 pmol kg(-1) min(-1)) had no effects. Obestatin (2500 pmol kg(-1) min(-1), starting 10 min before ghrelin) did not prevent the ability of ghrelin (500 pmol kg(-1) min(-1)) to shorten MMC cycle time. CONCLUSIONS AND IMPLICATIONS Obestatin has little ability to modulate rat GI motility.
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Levin F, Edholm T, Schmidt PT, Grybäck P, Jacobsson H, Degerblad M, Höybye C, Holst JJ, Rehfeld JF, Hellström PM, Näslund E. Ghrelin stimulates gastric emptying and hunger in normal-weight humans. J Clin Endocrinol Metab 2006; 91:3296-302. [PMID: 16772353 DOI: 10.1210/jc.2005-2638] [Citation(s) in RCA: 223] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
CONTEXT Ghrelin is produced primarily by enteroendocrine cells in the gastric mucosa and increases gastric emptying in patients with gastroparesis. MAIN OBJECTIVE The objective of the study was to evaluate the effect of ghrelin on gastric emptying, appetite, and postprandial hormone secretion in normal volunteers. DESIGN This was a randomized, double-blind, crossover study. SUBJECTS Subjects included normal human volunteers and patients with GH deficiency. INTERVENTION Intervention included saline or ghrelin (10 pmol/kg.min) infusion for 180 min after intake of a radioactively labeled omelette (310 kcal) or GH substitution in GH-deficient patients. MAIN OUTCOME MEASURES Measures consisted of gastric empty-ing parameters and postprandial plasma levels of ghrelin, cholecystokinin, glucagon-like peptide-1, peptide YY, and motilin. RESULTS The emptying rate was significantly faster for ghrelin (1.26 +/- 0.1% per minute), compared with saline (0.83% per minute) (P < 0.001). The lag phase (16.2 +/- 2.2 and 26.5 +/- 3.8 min) and half-emptying time (49.4 +/- 3.9 and 75.6 +/- 4.9 min) of solid gastric emptying were shorter during ghrelin infusion, compared with infusion of saline (P < 0.001). The postprandial peak in plasma concentration for cholecystokinin and glucagon-like peptide-1 occurred earlier and was higher during ghrelin infusion. There was no significant effect of ghrelin on plasma motilin or peptide YY. There was no difference in gastric emptying before and after GH substitution. CONCLUSION Our results demonstrate that ghrelin increases the gastric emptying rate in normal humans. The effect does not seem to be mediated via GH or motilin but may be mediated by the vagal nerve or directly on ghrelin receptors in the stomach. Ghrelin receptor agonists may have a role as prokinetic agents.
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Lundberg S, Holst M, Hellström PM. Expression of iNOS mRNA associated with suppression of colonic contraction in rat colitis. Acta Physiol (Oxf) 2006; 187:489-94. [PMID: 16866779 DOI: 10.1111/j.1748-1716.2006.01576.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Nitric oxide (NO) synthesis and inducible NO synthase (NOS) expression are increased in colon of patients with inflammatory bowel disease (IBD) and associated with decreased contractility. The aim was to investigate which subtype of NOS that is activated in experimental colitis. METHODS Experimental colitis was induced in Sprague-Dawley rats by Escherichia coli endotoxin. Expression of different subtypes of NOS was compared in normal and inflamed colon using reverse transcriptase-polymerase chain reaction. In organ baths, isometric contractile responses to acetylcholine (ACh) were studied in the colon, before and after incubation with the NOS inhibitor; N(omega)-nitro-L-arginine methyl ester (L-NAME) and NO donor glyceryl trinitrate. RESULTS Inflammation decreased colonic contraction to ACh from a pD(2) value of 7.09 +/- 0.16 to 5.30 +/- 0.17 (P < 0.001), and reduced maximal response to ACh. Pre-treatment with L-NAME reversed contractility and shifted the pD(2) for ACh from 5.30 +/- 0.17 to 6.60 +/- 0.19 (P < 0.001) along with a normalized contraction efficacy. RT-PCR product of iNOS was obtained only in rats treated with endotoxin. CONCLUSION Expression of iNOS is increased in inflamed colonic tissue. The induced overproduction of NO is likely to be responsible for the decreased motility in colitis where NO is suggested to exert a suppressive tone on colonic contractility, which is reversed by blockade of the enzyme.
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Schmidt PT, Degerblad M, Lindström E, Sundqvist M, Näslund E, Gillberg PG, Husebye E, Theodorsson E, Hellström PM. Circulating ghrelin levels after food intake during different phases of the migrating motor complex in man. Eur J Clin Invest 2006; 36:503-8. [PMID: 16796608 DOI: 10.1111/j.1365-2362.2006.01656.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND The timing of the migrating motor complexes (MMC) at food intake may influence gastric emptying and release of regulatory hormones. This report studies the relationships between phases I (motor quiescence) and II (intermediate frequency contractions) of MMC and prandial gut hormone response. MATERIALS AND METHODS Seven fasting volunteers ingested a meal during phase I or II of MMC verified by manometry, using paracetamol as a marker for gastric emptying. Blood was sampled before, during and 210 min after food intake for analysis of ghrelin, motilin, insulin and paracetamol. RESULTS The basal level of ghrelin during phase I was 127.5 +/- 25.4 pmol L(-1) and during phase II was 132.4 +/- 24.8 pmol L(-1). After food intake during phase I, ghrelin fell to 77.2 +/- 10 pmol L(-1); in phase II it fell to 82.7 +/- 17.8 pmol L(-1) within 60 min and returned to baseline levels after 120 min. Baseline levels of motilin were 16 +/- 2 pmol L(-1) and 18 +/- 3 pmol L(-1) during phases I and II, respectively. After food, motilin decreased to 8.5 +/- 0.7 pmol L(-1) and 8.7 +/- 1.0 pmol L(-1) within 60 min and returned to baseline after 90 min. Insulin levels in phases I and II were 8.1 +/- 1.2 mU L(-1) and 8.6 +/- 0.7 mU L(-1), respectively, reaching 138.9 +/- 35.6 mU L(-1) and 167.4 +/- 30.0 mU L(-1) at 45 min postprandially. CONCLUSIONS The nutritional status of the gastrointestinal tract at food intake had only a limited impact on plasma ghrelin. After food intake, plasma ghrelin drops, similar to motilin, and resumes preprandial levels within 120 min.
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Levin F, Edholm T, Schmidt PT, Grybäck P, Jacobsson H, Degerblad M, Höybye C, Holst JJ, Rehfeld JF, Hellström PM, Näslund E. Ghrelin stimulates gastric emptying and hunger in normal-weight humans. THE JOURNAL OF CLINICAL ENDOCRINOLOGY AND METABOLISM 2006. [PMID: 16772353 DOI: 10.1210/jc.2005- 2638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Ghrelin is produced primarily by enteroendocrine cells in the gastric mucosa and increases gastric emptying in patients with gastroparesis. MAIN OBJECTIVE The objective of the study was to evaluate the effect of ghrelin on gastric emptying, appetite, and postprandial hormone secretion in normal volunteers. DESIGN This was a randomized, double-blind, crossover study. SUBJECTS Subjects included normal human volunteers and patients with GH deficiency. INTERVENTION Intervention included saline or ghrelin (10 pmol/kg.min) infusion for 180 min after intake of a radioactively labeled omelette (310 kcal) or GH substitution in GH-deficient patients. MAIN OUTCOME MEASURES Measures consisted of gastric empty-ing parameters and postprandial plasma levels of ghrelin, cholecystokinin, glucagon-like peptide-1, peptide YY, and motilin. RESULTS The emptying rate was significantly faster for ghrelin (1.26 +/- 0.1% per minute), compared with saline (0.83% per minute) (P < 0.001). The lag phase (16.2 +/- 2.2 and 26.5 +/- 3.8 min) and half-emptying time (49.4 +/- 3.9 and 75.6 +/- 4.9 min) of solid gastric emptying were shorter during ghrelin infusion, compared with infusion of saline (P < 0.001). The postprandial peak in plasma concentration for cholecystokinin and glucagon-like peptide-1 occurred earlier and was higher during ghrelin infusion. There was no significant effect of ghrelin on plasma motilin or peptide YY. There was no difference in gastric emptying before and after GH substitution. CONCLUSION Our results demonstrate that ghrelin increases the gastric emptying rate in normal humans. The effect does not seem to be mediated via GH or motilin but may be mediated by the vagal nerve or directly on ghrelin receptors in the stomach. Ghrelin receptor agonists may have a role as prokinetic agents.
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Schmidt PT, Näslund E, Grybäck P, Jacobsson H, Holst JJ, Hilsted L, Hellström PM. A role for pancreatic polypeptide in the regulation of gastric emptying and short-term metabolic control. J Clin Endocrinol Metab 2005; 90:5241-6. [PMID: 15998783 DOI: 10.1210/jc.2004-2089] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
CONTEXT Previous studies using pancreatic polypeptide (PP) infusions in humans have failed to show an effect on gastric emptying, glucose metabolism, and insulin secretion. This might be due to the use of nonhuman sequences of the peptide. OBJECTIVE The objective of this study was to use synthetic human PP to study gastric emptying rates of a solid meal and postprandial hormone secretion and glucose disposal as well as the gastric emptying rate of water. DESIGN This was a single-blind study. SETTING The study was performed at a university hospital. PARTICIPANTS Fourteen healthy adult subjects were studied. INTERVENTIONS Infusion of saline or PP at 0.75 or 2.25 pmol/kg.min was given to eight subjects (gastric emptying of solid food), and infusion of saline or PP at 2.25 pmol/kg.min was given to six subjects (gastric emptying of water). MAIN OUTCOME MEASURES The main outcome measures were gastric emptying of solids (scintigraphy), hunger ratings (visual analog scale), and plasma concentrations of PP, insulin, glucagon, somatostatin, glucagon-like peptide 1, glucose, and gastric emptying of plain water (scintigraphy). RESULTS PP prolonged the lag phase and the half-time of emptying of the solid meal. The change in hunger rating, satiety, desire to eat after the meal, or prospective consumption was not affected. The postprandial rise in plasma glucose was prolonged by PP. The postprandial rise in insulin was also delayed by PP. PP had no significant effect on the emptying of water. CONCLUSIONS PP inhibits gastric emptying of solid food and delays the postprandial rise in plasma glucose and insulin. PP is suggested to have a physiological role in the pancreatic postprandial counterregulation of gastric emptying and insulin secretion.
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Ehrström M, Gustafsson T, Finn A, Kirchgessner A, Grybäck P, Jacobsson H, Hellström PM, Näslund E. Inhibitory effect of exogenous orexin a on gastric emptying, plasma leptin, and the distribution of orexin and orexin receptors in the gut and pancreas in man. J Clin Endocrinol Metab 2005; 90:2370-7. [PMID: 15671114 DOI: 10.1210/jc.2004-1408] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Orexin A (OXA) is a novel peptide that appears to play a role in the regulation of food intake, arousal, and energy balance. The aim of this study was to study the effect of iv infusion of OXA on gastric emptying, appetite, leptin, ghrelin, and glucose metabolism in man (six normal men) and the localization of OXA and orexin receptors (OXRs) 1 and 2 in the human gut. Gastric emptying was studied scintigraphically after ingestion of a 99mTc-labeled omelet and iv infusion of OXA (10 pmol/kg.min). Appetite ratings and blood samples were obtained at regular intervals. The immunohistochemical distribution of OXA and OXRs was examined using antibodies recognizing OXA, OX1R, and OX2R in human gastrointestinal tissue. OXA had no effect on lag phase or gastric half-emptying time. However, the gastric emptying rate was significantly slower without affecting appetite ratings. Plasma concentrations of insulin were increased by OXA, whereas plasma leptin decreased and ghrelin was unchanged. OXA immunoreactivity was observed in a subset of neurons and varicose nerve fibers in the mucosa, ganglia, and circular muscle layer and mucosal endocrine cells in the stomach and small intestine. OXA-immunoreactive cells in the islets of Langerhans contained insulin with a subset expressing OX2R. In conclusion, peripheral OXA seems to slightly affect the regulation of gastric emptying in humans without affecting appetite ratings. OXA decreased plasma levels of leptin, suggesting a possible interaction between leptin and OXA in the regulation of energy homeostasis.
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Schmidt PT, Näslund E, Grybäck P, Jacobsson H, Hartmann B, Holst JJ, Hellström PM. Peripheral administration of GLP-2 to humans has no effect on gastric emptying or satiety. ACTA ACUST UNITED AC 2004; 116:21-5. [PMID: 14599711 DOI: 10.1016/s0167-0115(03)00175-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) are secreted in parallel to the circulation after a meal. Intravenous (IV) GLP-1 has an inhibitory effect on gastric emptying, hunger and food intake in man. In rodents, central administration of GLP-2 increases satiety similar to GLP-1. The aim of the present study was to assess the effect of IV administered GLP-2 on gastric emptying and feelings of hunger in human volunteers. In eight (five men) healthy subjects (age 31.1+/-2.9 years and BMI 24.1+/-1.0 kg m(-2)), scintigraphic solid gastric emptying, hunger ratings (VAS) and plasma concentrations of GLP-2 were studied during infusion of saline or GLP-2 (0.75 and 2.25 pmol kg(-1) min(-1)) for a total of 180 min. Concentrations of GLP-2 were elevated to a maximum of 50 and 110 pmol l(-1) for 0.75 and 2.25 pmol kg(-1) min(-1) infusion of GLP-2, respectively. There was no effect of GLP-2 on either the lag phase (29.5+/-4.4, 26.0+/-5.2 and 21.2+/-3.6 min for saline, GLP-2 0.75 or 2.25 pmol kg(-1) min(-1), respectively) or the half emptying time (84.5+/-6.1, 89.5+/-17.8 and 85.0+/-7.0 min for saline, GLP-2 0.75 or 2.25 pmol kg(-1) min(-1), respectively). The change in hunger rating after the meal to 180 min was also unaffected by infusion of GLP-2. GLP-2 does not seem to mediate the ileal brake mechanism.
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Ehrström M, Näslund E, Levin F, Kaur R, Kirchgessner AL, Theodorsson E, Hellström PM. Pharmacokinetic profile of orexin A and effects on plasma insulin and glucagon in the rat. ACTA ACUST UNITED AC 2004; 119:209-12. [PMID: 15120482 DOI: 10.1016/j.regpep.2004.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2003] [Revised: 01/18/2004] [Accepted: 02/05/2004] [Indexed: 10/26/2022]
Abstract
Orexin A (OXA) is found in the central nervous system (CNS) and in the gut. Peripheral administration of OXA to rats results in an inhibition of fasting motility. Plasma OXA increases during fasting and central administration of OXA increases food intake. The aim of the present study was to assess the pharmacokinetic profile of OXA and the effect of intravenously (i.v.) administered OXA on plasma concentrations of insulin and glucagon concentrations. Rats were given OXA i.v. (100 pmol kg(-1) min(-1)) for time periods of 0, 10, 20, 30 min and for 10, 20, 30 min after ceasing a 30-min infusion. After each time period, rats were then sacrificed and blood obtained. OXA was also administered at increasing doses (0, 100, 300 and 500 pmol kg(-1) min(-1)) for 30 min and blood was obtained. Plasma OXA, insulin and glucagon levels were measured using commercially available radioimmunoassay (RIA) kits. The plasma half-life of OXA was 27.1+/-9.5 min. Stepwise increasing infusion rates of OXA confirmed a linear concentration-time curve and thus first-order kinetics. Its volume of distribution indicated no binding to peripheral tissues. Plasma glucagon decreased during infusion of OXA, while insulin was unaffected. Plasma OXA was raised fourfold after food intake. Thus, OXA has a longer plasma half-life than many other peptides found in the gut. This needs to be taken into account when assessing effects of OXA on biological parameters after peripheral administration.
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Ljung T, Karlén P, Schmidt D, Hellström PM, Lapidus A, Janczewska I, Sjöqvist U, Löfberg R. Infliximab in inflammatory bowel disease: clinical outcome in a population based cohort from Stockholm County. Gut 2004; 53:849-53. [PMID: 15138212 PMCID: PMC1774085 DOI: 10.1136/gut.2003.018515] [Citation(s) in RCA: 237] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/25/2003] [Indexed: 01/01/2023]
Abstract
BACKGROUND Several placebo controlled studies have demonstrated the efficacy of infliximab in inflammatory bowel disease (IBD) but the potential toxicity of this new biological compound has been less studied. AIM To assess the use of infliximab in IBD in a population based cohort, with special emphasis on the occurrence of severe adverse events and mortality. PATIENTS All patients with IBD treated with infliximab between 1999 and 2001 in Stockholm County were evaluated. METHODS Prospective registration of clinical data was carried out. Retrospective analyses were made of possible adverse events occurring in relation to infliximab treatment. Adverse events requiring pharmacological treatment or hospitalisation were defined as severe. Clinical response was assessed as remission, response, or failure. RESULTS A cohort comprising 217 patients was assembled: 191 patients had Crohn's disease (CD), and infliximab was used off label for ulcerative colitis (UC) in 22 patients. Four patients were treated for indeterminate colitis (IC). Mean age was 37.6 (0.9) years (range 8-79). The mean number of infliximab infusions was 2.6 (0.1) (range 1-11). Forty two severe adverse events were registered in 41 patients (CD, n = 35). Eleven of the severe adverse events occurred postoperatively (CD, n = 6). Three patients with CD developed lymphoma (of which two were fatal), opportunistic infections occurred in two patients (one with UC, fatal), and two patients with severe attacks of IBD died due to sepsis (one with CD, one postoperatively with UC). One additional patient with UC died from pulmonary embolism after colectomy. Mean age in the group with fatal outcome was 62.7 years (range 25-79). The overall response rate was 75% and did not differ between the patient groups. CONCLUSIONS Infliximab was efficacious as an anti-inflammatory treatment when assessed in a population based cohort of patients with IBD. However, there appear to be a significant risk of deleterious and fatal adverse events, particularly in elderly patients with severe attacks of IBD. Off label use of infliximab in UC and IC should be avoided until efficacy is proven in randomised controlled trials. The underlying risk of developing malignancies among patients with severe or chronically active CD in need of infliximab treatment is not known but the finding of a 1.5% annual incidence of lymphoma emphasises the need for vigilant surveillance with respect to this malignant complication.
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Reinders CI, Hellström PM, Björk J, Weitzberg E, Lundberg JO. Effect of intravenous L-NMMA on nitric oxide production in collagenous colitis. Scand J Gastroenterol 2004; 39:32-6. [PMID: 14992559 DOI: 10.1080/00365520310007611] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Nitric oxide (NO) is greatly increased in the colon of patients with inflammatory bowel disease of different aetiology, including collagenous colitis. In man, NO can be generated from NO synthases as well as from non-enzymatic sources. The source of the NO found in luminal intestinal gas has not been exactly pinpointed. We investigated the effect of the NO synthase inhibitor L-NMMA on intestinal concentrations of NO in patients with clinically active collagenous colitis. In addition, we measured NO levels from the respiratory tract. METHODS Ten patients with active collagenous colitis were studied. NO levels were measured from the respiratory tract and in the rectum before and after i.v. administration of L-NMMA (7.5 mg/kg) using a chemiluminescence method. RESULTS Airway NO release decreased markedly, and mean arterial blood pressure increased in all patients following L-NMMA treatment. Basal rectal NO levels were high (median > 10000 ppb) and decreased markedly in 5 patients after L-NMMA. In contrast, NO levels remained completely unchanged or even increased in the other 5 patients. CONCLUSION Rectal levels of NO are greatly increased in patients with symptomatic collagenous colitis. Intravenous administration of an NO synthase inhibitor reduced rectal NO only in half of the patients despite clear evidence of effective systemic NO synthase inhibition. This could indicate alternative NOS-independent sources of intestinal NO in this disease.
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Ehrström M, Näslund E, Ma J, Kirchgessner AL, Hellström PM. Physiological regulation and NO-dependent inhibition of migrating myoelectric complex in the rat small bowel by OXA. Am J Physiol Gastrointest Liver Physiol 2003; 285:G688-95. [PMID: 12816759 DOI: 10.1152/ajpgi.00061.2003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Orexin A (OXA)-positive neurons are found in the lateral hypothalamic area and the enteric nervous system. The aim of this study was to investigate the mechanism of OXA action on small bowel motility. Electrodes were implanted in the serosa of the rat small intestine for recordings of myoelectric activity during infusion of saline or OXA in naive rats, vagotomized rats, rats pretreated with guanethidine (3 mg/kg) or N(omega)-nitro-L-arginine (L-NNA; 1 mg/kg). Naive rats were given a bolus of the orexin receptor-1 (OX1R) antagonist (SB-334867-A; 10 mg/kg), and the effect of both OXA and SB-334867-A on fasting motility was studied. Double-label immunocytochemistry with primary antibodies against OXA, neuronal nitric oxide synthase (nNOS), and OX1R was performed. OXA induced a dose-dependent prolongation of the cycle length of the migrating myoelectric complex (MMC) and, in the higher doses, replaced the activity fronts with an irregular spiking pattern. Vagotomy or pretreatment with guanethidine failed to prevent the response to OXA. The OXA-induced effect on the MMC cycle length was completely inhibited by pretreatment with L-NNA (P < 0.05), as did SB-334867-A. The OX1R antagonist shortened the MMC cycle length from 14.1 (12.0-23.5) to 11.0 (9.5-14.7) min (P < 0.05) during control and treatment periods, respectively. Colocalization of OXA and nNOS was observed in myenteric neurons of the duodenum and nerve fibers in the circular muscle. Our results indicate that OXA inhibition of the MMC involves the OX1R and that activation of a L-arginine/NO pathway possibly originating from OX1R/nNOS-containing neurons in the myenteric plexus may mediate this effect. Endogenous OXA may have a physiological role in regulating the MMC.
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Schmidt PT, Lördal M, Gazelius B, Hellström PM. Tachykinins potently stimulate human small bowel blood flow: a laser Doppler flowmetry study in humans. Gut 2003; 52:53-6. [PMID: 12477759 PMCID: PMC1773513 DOI: 10.1136/gut.52.1.53] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND The two tachykinins substance P and neurokinin A are abundantly present in the gastrointestinal tract. Substance P preferring neurokinin 1 receptors are mainly found in submucosal blood vessels while neurokinin A preferring neurokinin 2 receptors seem to be confined to smooth muscle cells. Tachykinin effects on intestinal mucosal blood flow in humans are not known. AIM To study the effects of substance P and neurokinin A on small bowel mucosal blood flow in humans. METHODS A manometry tube supplied with single fibre microprobes recorded mucosal blood flow in the proximal small bowel using laser Doppler flowmetry, concomitant with luminal manometry, defining phases I, II, and III of the migrating motor complex. Simultaneously, flowmetry of temporal skin was performed. Under fasting conditions saline was infused intravenously over four hours followed by infusion of substance P, neurokinin A, or saline. RESULTS During phase I, substance 1-6 pmol/kg/min increased mucosal blood flow dose dependently by a maximum of 158%. Blood flow of the temporal skin increased in parallel. Neurokinin A 6-50 pmol/kg/min increased mucosal blood flow maximally by 86% at 25 pmol/kg/min while blood flow of temporal skin increased at all doses. Substance P at all doses and neurokinin A at the highest dose only, increased pulse rate. Systolic blood pressure was unchanged by either peptide while substance P at the highest dose decreased diastolic pressure. CONCLUSION Tachykinins increase blood flow of the small bowel and temporal skin. With substance P being more potent than neurokinin A, these effects are probably mediated through neurokinin 1 receptors.
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Ljung T, Staun M, Grove O, Fausa O, Vatn MH, Hellström PM. Pyoderma gangrenosum associated with crohn disease: effect of TNF-alpha blockade with infliximab. Scand J Gastroenterol 2002; 37:1108-10. [PMID: 12374238 DOI: 10.1080/003655202320378338] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Eight patients with pyoderma gangrenosum associated with Crohn disease were treated with infliximab. All had active mucosal inflammation indicated by endoscopic examination. Within 1-4 months, infliximab treatment resulted in complete healing of the pyoderma gangrenosum in 3 cases (1 parastomal, 2 lower limb), partial healing in 3 (2 parastomal, 1 lower limb) and temporary improvement in 2. Adverse effects such as skin rash, pneumonia and diarrhoea were seen in three patients. Our results imply that infliximab has a therapeutic potential on skin manifestations associated with inflammatory bowel disease, even though successful treatment may require repeat courses of infliximab infusions.
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Abstract
BACKGROUND Gastrointestinal symptoms are common and important for the quality of life in patients with myotonic dystrophy (MD). Gastric emptying was studied in patients with MD who suffered from symptoms suggesting slow gastric emptying and the effect of prokinetic treatment was evaluated. METHODS Gastric emptying was studied in 10 patients with MD who were suffering from nausea, early satiety, bloating, regurgitation, vomiting, or abdominal pain using a (99)Tc-labelled test meal, and was compared with gastric emptying in a group of healthy controls. The patients were subsequently treated with erythromycin and their gastrointestinal symptoms were recorded and the gastric emptying test was repeated. RESULTS Patients with MD had a significantly longer gastric lag phase (46.1 +/- 4.3 vs. 31.9 +/- 4.0 min, P = 0.03), a slower emptying phase (7.1 +/- 0.9 vs. 10.2 +/- 0.9 kJ min(-1), P = 0.02) and a longer half-emptying time, T50 (141.7 +/- 10.5 vs. 98.6 +/- 8.7 min, P = 0.01) than a matched control group. Erythromycin did not stimulate the gastric emptying rate. The effect on gastrointestinal symptoms was modest, except for a reduction of diarrhoea. CONCLUSIONS Patients with MD suffering from nausea, vomiting and early satiety, displayed a slow gastric emptying. Treatment with erythromycin had only moderate effect on gastric emptying or gastric symptoms, but reduced diarrhoea in a majority of the patients.
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Freedman J, Grybäck P, Lindqvist M, Granström L, Lagergren J, Hellström PM, Jacobsson H, Näslund E. Gastric emptying and duodeno-gastro-oesophageal reflux in gastro-oesophageal reflux disease. Dig Liver Dis 2002; 34:477-83. [PMID: 12236480 DOI: 10.1016/s1590-8658(02)80105-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Previous studies present conflicting results regarding relationship between gastric emptying and gastro-oesophageal reflux disease. Reflux of duodenal content to oesophagus is generally considered to be associated with more severe disease. AIM To assess presence of a gastric emptying disorder in persons with reflux of duodenal contents to oesophagus and to identify any correlation with gastric emptying and oesophageal motility. METHODOLOGY A total of 15 subjects with (B+) and 15 subjects without (B-) bile reflux to oesophagus determined by 24-hour bilirubin monitoring were studied with scintigraphic solid gastric emptying and 24-hour oesophageal manometry. RESULTS There was no difference in lag phase [median 23.7 (range 10.8-44.0) vs 24.6 (8.1-40.1) min], half emptying time [74.6 (48.0-93.6) vs 82.8 (54.4-153.9) min] or emptying rate [0.89 (0.59-1.34) vs 0.83 (0.36-1. 15)%/min] for B- and B+ subjects, respectively. In addition, there was no difference in emptying rate of gastric fundus between B- and B+ subjects. Subjects with bile reflux had less effective oesophageal contractions of oesophageal body [9.4(3.3-37)%] compared to subjects without bile reflux [32(19-47)%, p = 0.002]. However, there was no correlation between oesophageal motility and gastric emptying. CONCLUSION Results suggest that a gastric emptying disorder is a less likely contributing cause of bile reflux to the oesophagus, but bile reflux is associated with less effective oesophageal motility.
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Näslund E, Ehrström M, Ma J, Hellström PM, Kirchgessner AL. Localization and effects of orexin on fasting motility in the rat duodenum. Am J Physiol Gastrointest Liver Physiol 2002; 282:G470-9. [PMID: 11841997 DOI: 10.1152/ajpgi.00219.2001] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The orexins [orexin A (OXA) and orexin B (OXB)] are novel neuropeptides that increase food intake in rodents. The aim of this study was to determine the distribution of orexin and orexin receptors (OX1R and OX2R) in the rat duodenum and examine the effects of intravenous orexin on fasting gut motility. OXA-like immunoreactivity was found in varicose nerve fibers in myenteric and submucosal ganglia, the circular muscle, the mucosa, submucosal and myenteric neurons, and numerous endocrine cells of the mucosa. OXA neurons displayed choline acetyltransferase immunoreactivity, and a subset contained vasoactive intestinal peptide. OXA-containing endocrine cells were identified as enterochromaffin (EC) cells based on the presence of 5-hydroxytryptamine immunoreactivity. OX1R was expressed by neural elements of the gut, and EC cells expressed OX2R. OXA at 100 and 500 pmol x kg(-1) x min(-1) significantly increased the myoelectric motor complex (MMC) cycle length compared with saline. Similarly, OXB increased the MMC cycle length at 100 pmol x kg(-1) x min(-1), but there was no further effect at 500 pmol x kg(-1) x min(-1). We postulate that orexins may affect the MMC through actions on enteric neurotransmission after being released from EC cells and/or enteric neurons.
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