Dose-related effects of motilin on proximal gastrointestinal motility

Efficacy and safety of Zhishixiaopi decoction in functional dyspepsia: A meta-analysis of randomized controlled trials

BACKGROUND

Functional dyspepsia (FD) refers to a group of clinical symptoms caused by gastric and duodenal dysfunction. Which is a chronic functional disorder of the gastrointestinal tract with no cure. Zhishixiaopi decoction (ZSXP) is a type of Chinese herbal prescription that for treating FD. Although some randomized controlled trials (RCTs) report that ZSXP can significantly improve FD clinical symptoms and/or laboratory results, the trial design varies greatly among studies, making it challenging to draw a conclusion of the efficacy of ZSXP in treating FD.

DESIGN

A systematic review and a meta-analysis.

SETTING

Mianyang Central Hospital.

OBJECTIVE

We conducted a systematic review and a meta-analysis to evaluate the efficacy and safety of ZSXP for treating FD.

METHODS

We developed inclusion and exclusion criteria based on FD diagnosed criteria, interventions to treat FD, and outcomes of these interventions. Search strategies combined disease terms, symptom terms, anatomy terms and intervention terms. Literature search was conducted on eight online databases in English or Chinese, including Medline (via PubMed), Embase (via Ovid), The Cochrane Library, Web of Science, China Biology Medicine (CBM), China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP), and Wanfang Database.

INTERVENTION

The experimental group received oral administration of ZSXP and had a complete treatment process. ZSXP needs to fully contain the key herbal ingredients, regardless of whether the dosage of each herb is consistent with the original prescription. The Control group received monotherapy or combination therapy of other Western medicine and had a complete treatment process.

OUTCOMES

The primary outcomes appraised were Total effective rate (TER), serum levels of Motilin(MOT), Gastrin(GAS) and Somatostatin (SS), Gastric emptying rate (GER) using a Barium meal method (GER(B)) and Gastric half emptying time using an Ultrasonic method (GHET(T1/2)). The Cochrane Bias Risk Tool was used for quality critical appraisal, Review Manager (RevMan) version 5.3 was used for statistical analysis.

RESULTS

A total of 21 medium-quality RCTs were included in the meta-analysis. All 21 included studies were conducted and completed in Mainland China from 1998 to 2020. The treatment duration was between two weeks to two months. The meta-analysis suggests that, compared with the Western medicine treatment group, ZSXP treatment was more effective to improving the TER in FD [Odds ratio, OR = 3.54, 95%CI:(2.49, 5.05), Z = 6.99, P<0.00001] without significant increase in adverse events. However, no statistical significance was found between the groups in serum MOT levels [Standard mean difference, SMD = 1.05, 95%CI:(-0.42, 2.53), Z = 1.04, P = 0.16], serum GAS levels [SMD = -0.16, 95%CI:(-1.20, 0.88), Z = 0.31, P = 0.76], serum SS levels [SMD = -0.04, 95%CI:(-1.97, 1.89), Z = 0.04, P = 0.97], GER(B) [SMD = 1.09, 95%CI:(-0.81, 3.00), Z = 1.12, P = 0.26]or GHET(T1/2) [Mean difference, MD = -2.18, 95%CI:(-5.55, 1.19), Z = 1.27, P = 0.20].

CONCLUSIONS

The meta-analysis suggests that Zhishixiaopi treatment is a relatively effective and safe traditional Chinese medicine prescription and could be used for functional dyspepsia treatment. Considering the limitations of this study, the conclusion needs to be further confirmed by high-quality, multi-center, and large-sample randomized controlled trials.

Why is motilin active in some studies with mice, rats, and guinea pigs, but not in others? Implications for functional variability among rodents

The gastrointestinal (GI) hormone motilin helps control human stomach movements during hunger and promotes hunger. Although widely present among mammals, it is generally accepted that in rodents the genes for motilin and/or its receptor have undergone pseudonymization, so exogenous motilin cannot function. However, several publications describe functions of low concentrations of motilin, usually within the GI tract and CNS of mice, rats, and guinea pigs. These animals were from institute‐held stocks, simply described with stock names (e.g., “Sprague–Dawley”) or were inbred strains. It is speculated that variation in source/type of animal introduces genetic variations to promote motilin‐sensitive pathways. Perhaps, in some populations, motilin receptors exist, or a different functionally‐active receptor has a good affinity for motilin (indicating evolutionary pressures to retain motilin functions). The ghrelin receptor has the closest sequence homology, yet in non‐rodents the receptors have a poor affinity for each other's cognate ligand. In rodents, ghrelin may substitute for certain GI functions of motilin, but no good evidence suggests rodent ghrelin receptors are highly responsive to motilin. It remains unknown if motilin has functional relationships with additional bioactive molecules formed from the ghrelin and motilin genes, or if a 5‐TM motilin receptor has influence in rodents (e.g., to dimerize with GPCRs and create different pharmacological profiles). Is the absence/presence of responses to motilin in rodents’ characteristic for systems undergoing gene pseudonymization? What are the consequences of rodent supplier‐dependent variations in motilin sensitivity (or other ligands for receptors undergoing pseudonymization) on gross physiological functions? These are important questions for understanding animal variation.

Ultrasound imaging for assessing functions of the GI tract

OBJECTIVE

In the following review we outline how ultrasound can be used to measure physiological processes in the gastrointestinal tract.

APPROACH

We have investigated the potential of ultrasound in assessing gastrointestinal physiology including original research regarding both basic methodology and clinical applications.

MAIN RESULTS

Our main findings show the use of ultrasound to study esophageal motility, measure volume and contractility of the stomach, assess motility, wall thickness, and perfusion of the small bowel, and evaluate wall vascularization and diameters of the large bowel.

SIGNIFICANCE

Ultrasound is a widely accessible technology that can be used for both scientific and clinical purposes. Being radiation-free and user friendly, the examination can be frequently repeated enabling longitudinal studies. Furthermore, it does not influence normal GI physiology, thus being useful to estimate motility and subtle changes in physiology. Accordingly, ultrasound scanning and physiological measurements may make a big difference for the scientist and the doctor; and for the patients who receive an efficient work-up.

Motilin: a panoply of communications between the gut, brain, and pancreas

Introduction: Motilin was first alluded to nearly a century ago. But it remains a rather abstruse peptide, in the shadow of its younger but more lucid 'cousin' ghrelin.Areas covered: The review aimed to bring to the fore multifarious aspects of motilin research with a view to aiding prioritization of future studies on this gastrointestinal peptide.Expert opinion: Growing evidence indicates that rodents (mice, rats, guinea pigs) do not have functional motilin system and, hence, studies in these species are likely to have a minimal translational impact. Both the active peptide and motilin receptor were initially localized to the upper gastrointestinal tract only but more recently - also to the brain (in both humans and other mammals with functional motilin system). Motilin is now indisputably implicated in interdigestive contractile activity of the gastrointestinal tract (in particular, gastric phase III of the migrating motor complex). Beyond this role, evidence is building that there is a cross-talk between motilin system and the brain-pancreas axis, suggesting that motilin exerts not only contractile but also orexigenic and insulin secretagogue actions.

Comparative Researches of Semen Arecae and Charred Semen Arecae on Gastrointestinal Motility, Motilin, Substance P, and CCK in Chronically Stressed Rats

Aims

To compare the effects of Semen Arecae (SA) and Charred Semen Arecae (CSA) on gastrointestinal motility, motilin, substance P (SP), and cholecystokinin (CCK) in chronically stressed rats.

Methods

Rats were randomly divided into control group and stress group. Rats in stress group were randomly exposed to a variety of unpredictable stimulations for 21 days. Then, the rats were treated orally with distilled water, SA, CSA, and mosapride for 7 days. Gastric residue rate and intestinal propulsion rate were evaluated. Serum levels of motilin and SP were measured by enzyme-linked immunosorbent assay (ELISA). CCK mRNA was quantified by using quantitative real-time PCR (qRT-PCR).

Results

Both SA and CSA improved the intestinal propulsion and reduced the gastric residue in chronically stressed rats. Furthermore, the serum levels of motilin and SP were significantly higher and the CCK mRNA expressions in intestine and hypothalamus were downregulated in SA and CSA groups. Furthermore, it was found that CSA is more effective.

Conclusion

Both SA and CSA enhanced gastrointestinal motility and increased serum levels of motilin and SP in chronically stressed rats via downregulating CCK mRNA expressions in intestine and hypothalamus. Importantly, CSA possessed more effective promoting effects.

Efficacy and Safety of Acupuncture for the Treatment of Functional Dyspepsia: Meta-Analysis

OBJECTIVES

Functional dyspepsia (FD) is a common gastrointestinal disorder. Currently, no established optimal treatment is available. The aim of this study was to assess the efficacy of acupuncture in relieving symptoms and improving quality of life in patients with FD.

METHODS

PubMed, MEDLINE, Web of Science, Sino-Med, China National Knowledge Infrastructure, VIP databases, and Google Scholar engine were searched from inception through April 2014 to identify randomized controlled trials of acupuncture therapy that reported on overall FD symptoms or FD-related quality of life as a primary outcome. The Cochrane Collaboration's risk of bias tool, RevMan 5.0, and Stata 12.0 software were used for meta-analysis. Data were pooled to calculate relative risk (RRs) and 95% confidence intervals (CIs) of substantial improvement after treatment for dichotomous data and mean differences (SMDs) and 95% CIs for continuous data using random-effects models.

RESULTS

Twenty-four English- and Chinese-language articles describing randomized, placebo-controlled, clinical trials involving 3097 patients were included. Acupuncture significantly improved FD symptoms in studies reporting outcomes using dichotomous (RR, 1.19; 95% CI, 1.12-1.27; p < 0.001) and continuous (standardized MD [SMD], -0.78; 95% CI, -1.21 to -0.35; p = 0.0004) variables. Pooled analyses showed that acupuncture improved FD-related (weighted MD [WMD], 5.97; 95% CI, 3.14-8.80; p = 0.0002) and health-related (WMD, 6.83; 95% CI, 3.02-10.65; p = 0.004) quality of life, without serious adverse events. However, acupuncture failed to increase plasma motilin concentration (SMD, 0.67; 95% CI, -0.07 to 1.42; p = 0.08).

CONCLUSIONS

Acupuncture appears to be efficacious in relieving FD symptoms and improving quality of life.

The effect of drugs and stimulants on gastric myoelectrical activity

Electrogastrography (EGG) is a non-invasive diagnostic method useful for the registration and analysis of gastric myoelectrical activity. Abnormalities within an electrogastrogram were found to correlate with a number of disorders and symptoms, like functional dyspepsia, diabetic gastroparesis and terminal hepatic or renal failure. The EGG is also a valuable diagnostic method enabling the evaluation of the effect of drugs on gastric myoelectrical activity, which can be intentional, as in the case of prokinetics, or can have an adverse character. Our review focuses on drugs with a proven impact on gastric myoelectrical activity and hence on the electrogastrogram. The paper assembles and discusses the results of investigations dealing with changes in the electrogastrograms evoked by various drugs. Moreover, the mechanisms of the influence on the gastric myoelectrical activity of drugs, curative substances and stimulants are presented.

Simotang enhances gastrointestinal motility, motilin and cholecystokinin expression in chronically stressed mice

AIM: To investigate the effect of Simotang (Decoction of Four Powered Drugs) on gastrointestinal motility, motilin and cholecystokinin expression in chronically stressed mice.

METHODS: Forty mice were randomly divided into control group, stress group (model group), mosapride group and Simotang group, 10 in each group. A variety of unpredictable stimulations were used to induce chronic stress in mice. Then, the mice were treated with distilled water, mosapride or Simotang for 7 d. Gastric emptying and intestinal propulsion function were detected. Serum level of motilin was measured by enzyme-linked immunosorbent assay. Expression of cholecystokinin (CCK) in intestine, spinal cord and brain of mice was detected by immunohistochemistry and semi-quantitative reverse transcription polymerase chain reaction, respectively.

RESULTS: Simotang improved the gastric emptying and intestinal propulsion in chronically stressed mice. Furthermore, the serum motilin level was significantly higher and the expression levels of CCK-positive cells and genes were significantly lower in intestine, spinal cord and brain of Simotang group than in those of model group (P < 0.05). No significant difference was found in serum motilin level and expression levels of CCK-positive cells and genes between the mosapride and Simotang groups.

CONCLUSION: Simotang enhances the gastrointestinal motility in chronically stressed mice by regulating the serum motilin level and the expression of cholecystokinin.

Endogenous gastric mediators: patho-physiological role and measurements

The protocols described in this unit are designed to present the major endogenous gastric mediators involved in the control of gastric acid secretion, namely gastrin and histamine, and in the regulation of gastric motility, which include motilin and ghrelin, under physiological and pathological conditions. The measurement of these mediators in plasma or serum of humans and animals by radioimmunoassay are described and their pathophysiological role is discussed.

Motilin receptor expression in smooth muscle, myenteric plexus, and mucosa of human inflamed and noninflamed intestine

BACKGROUND

Besides regulation of upper gastrointestinal motility, motilin seems to play a role in the inflammatory response. Motilin receptor expression in human intestine has not been studied thoroughly. This study aimed to describe the intestinal distribution of motilin receptors in inflammatory bowel disease (IBD) and control patients.

METHODS

Quantitative autoradiography, immunohistochemistry, and reverse-transcriptase polymerase chain reaction (RT-PCR) were used to detect motilin receptors in tissue of 25 IBD patients (13 Crohn's disease [CD], 12 ulcerative colitis [UC]) and 19 patients with a neoplasm (controls).

RESULTS

Median muscular motilin binding was 3 and 8 fmol/g tissue in colon and ileum, respectively. In the gastroduodenal region the median was higher (93 fmol/g). In UC colonic muscular motilin binding was significantly increased compared to controls (7 vs. 3 fmol/g, P < or = 0.05). Expression in CD was similar to controls. Besides the binding found in the muscular compartment, motilin binding was also found in the mucosa, which was even higher than in the muscle (3 versus 11 and 8 versus 27 fmol/g for colon and ileum (P < or = 0.06), respectively). RT-PCR and immunohistochemistry confirmed the mucosal motilin receptor expression. The mucosal motilin receptors were located in the epithelial cells. In the muscular compartment receptors were strongly present in the myenteric plexus and weakly in the smooth muscle cells. In IBD tissue the expression pattern was not different.

CONCLUSIONS

The motilin receptor is expressed in human colonic and ileal smooth muscle. Further, motilin receptor expression was also shown in the mucosa. Muscular binding in UC patients is increased but no different expression pattern was found.

Intragastric acidification inhibits motilin-induced phase III activity in humans

In a randomized, placebo-controlled crossover design we studied the effect of gastric acidification on motilin-induced interdigestive antropyloroduodenal motility. Ten healthy volunteers participated in the study consisting of four experiments. Each experiment started after a spontaneous occurring phase III and consisted of intragastric infusion of either saline or acid (0.08 mol L(-1) HCl) for 90 min and intravenous infusion of either saline or motilin (4 pmol kg(-1) min(-1)) for 30 min. Antropyloroduodenal motility and pH were recorded continuously for 240 min. Reoccurrence of phase III was significantly (P < 0.05) earlier during intragastric saline-intravenous motilin infusion compared with control (intragastric saline-intravenous saline), 52 min (range 25-79) and 113 min (84-141) respectively. This effect was completely abolished during intragastric acid-intravenous motilin infusion, 112 min (82-142). The percentage of phase III of antral origin was significantly (P < 0.05) higher during intragastric saline-intravenous motilin infusion (90%) compared with control (30%). The mean area under the contraction (AUC) for phase II was significantly (P < 0.05) lower during intragastric saline-intravenous motilin infusion and intragastric acid-intravenous saline infusion compared with control. It is concluded that in humans intragastric acidification inhibits the effect of motilin on antroduodenal motility, decreases the AUC of antral phase II contractions and delays the occurrence of phase III of the migrating motor complex.

Ghrelin stimulates gastric emptying but is without effect on acid secretion and gastric endocrine cells

Ghrelin, a recently discovered peptide hormone, is produced by endocrine cells in the stomach, the so-called A-like cells. Ghrelin binds to the growth hormone (GH) secretagogue receptor and releases GH. It is claimed to be orexigenic and to control gastric acid secretion and gastric motility. In this study, we examined the effects of ghrelin, des-Gln14-ghrelin, des-octanoyl ghrelin, ghrelin-18, -10 and -5 (and motilin) on gastric emptying in mice and on gastric acid secretion in chronic fistula rats and pylorus-ligated rats. We also examined whether ghrelin affected the activity of the predominant gastric endocrine cell populations, G cells, ECL cells and D cells. Ghrelin and des-Gln14-ghrelin stimulated gastric emptying in a dose-dependent manner while des-octanoyl ghrelin and motilin were without effect. The C-terminally truncated ghrelin fragments were effective but much less potent than ghrelin itself. Ghrelin, des-Gln14-ghrelin and des-octanoyl ghrelin neither stimulated nor inhibited gastric acid secretion, and ghrelin, finally, did not affect secretion from either G cells, ECL cells or D cells.

Effects of a nonpeptide motilin receptor antagonist on proximal gastric motor function

AIM

To assess the effects of the motilin receptor antagonist RWJ-68023 on basal and motilin-stimulated proximal gastric volume.

METHODS

Eighteen healthy male volunteers received RWJ-68023 in two different doses or placebo for 135 min. After 45 min, subjects received a motilin infusion for 90 min. Proximal gastric volume was measured with a barostat at constant pressure and during isobaric distensions. Abdominal symptoms were scored using visual analogue scales. Motilin and RWJ-68023 concentrations were assessed by radioimmunoassay and liquid chromatography-mass spectrometry, respectively.

RESULTS

Both dosages of RWJ-68023 were safe and well tolerated. The most common adverse events were of gastrointestinal origin. RWJ-68023 did not affect basal proximal gastric volume, but the high-dose RWJ-68023 reduced the contractile effect of motilin on the stomach. This antagonizing effect of RWJ-68023 was only significant (P = 0.014) during the distension procedure.

CONCLUSIONS

The RWJ-68023 doses used in this study were selected to accomplish plasma concentrations that would block the motilin effect entirely. However, the antagonizing effect of RWJ-68023 was partial and only present when the tonic condition of the stomach was modulated by motilin.

Gallbladder volume as a biomarker for the motilin effect in healthy volunteers and patients with functional dyspepsia

AIM

To investigate a motilin effect on gallbladder volume in healthy volunteers and patients with functional dyspepsia.

METHODS

Forty-three healthy volunteers and 10 patients with functional dyspepsia received motilin (4 pmol.min/kg) or placebo in four separate double-blind, randomized, placebo-controlled, cross-over studies. The gallbladder volume was measured by ultrasonography. Analysis of variance of the combined data of these studies was performed to investigate a motilin effect on gallbladder volume and potential differences between patients and healthy volunteers.

RESULTS

The baseline gallbladder volume was similar for placebo and motilin treatment, as well as for patients and healthy volunteers. Motilin, compared with placebo, significantly decreased the gallbladder volume in healthy volunteers (P = 0.003) and patients (P < 0.0001). A linear concentration-response relationship was observed. The decrease in gallbladder volume by motilin was greater in patients (P = 0.03). The motilin effect was consistent between studies.

CONCLUSION

The interdigestive gallbladder volume is a non-invasive end-point for motilin activity, displaying a consistent response across studies, a clear response to motilin and a clear concentration-response relationship. However, it is less suitable as a biomarker for future pharmacological studies on motilin agonists or antagonists as the effect is probably indirect, and a relatively large study population of 27 subjects is required to demonstrate a 15% decrease in gallbladder volume. Further investigation is required to confirm altered gallbladder motility as a feature of functional dyspepsia.

The effect of motilin on the rectum in healthy volunteers

AIMS

The role of motilin in the regulation of upper gastrointestinal (GI) motility is well defined. However, little is known about the effects on the distal GI tract. To investigate the effect of exogenous motilin on rectal function, barostat measurements in the rectum were performed and lower abdominal symptoms were scored.

METHODS

Eight fasted, healthy volunteers were infused intravenously with synthetic motilin or placebo over 90 min in a double-blind, randomized, cross-over design. Rectum volume was measured with a barostat device during constant pressure and during isobaric distensions. Lower abdominal symptoms were scored by visual analogue scales. Plasma motilin concentrations were measured by radioimmunoassay.

RESULTS

Baseline rectum volumes were similar between treatments: 185 +/- 62 mL (motilin) and 136 +/- 41 mL (placebo). During the constant pressure procedure, motilin increased rectum volume [area under the effect curve (AUEC)] by 6%[95% confidence interval (CI) -3, 16] of baseline, compared with placebo. During isobaric distensions motilin increased rectum volume (AUEC) by 43 mL (95% CI 0.4, 85; P < 0.05) and compliance by 10 mL mmHg-1 (95% CI 0.3, 20; P < 0.05) relative to placebo. Motilin did not induce changes in the sensation of rectal feelings.

CONCLUSION

Exogenous motilin increased rectal compliance in healthy volunteers, without affecting rectal sensations.

Motilin effects on the proximal stomach in patients with functional dyspepsia and healthy volunteers

This study investigates motilin effects on the proximal stomach in patients with functional dyspepsia (FD) and healthy volunteers. Eight healthy volunteers and 12 patients with FD were infused with synthetic motilin or placebo. Proximal gastric volume was measured with a barostat at constant pressure and during isobaric distensions. Abdominal symptoms were scored by visual analog scales. Plasma motilin concentrations were measured by radioimmunoassay. Motilin concentrations and baseline gastric volumes were similar for patients and healthy volunteers. Motilin, compared with placebo, reduced gastric volume by 112 ml [F(29,195); confidence interval (CI) 95%] in patients and by 96 ml [F(-7,200); CI 95%] in healthy volunteers. In patients, motilin decreased compliance by 76 ml/mmHg [F(9,143); CI 95%] compared with placebo, which was similar in volunteers [66 ml/mmHg; F(11,120); CI 95%]. Patients were more nauseous during motilin compared with placebo (P = 0.04), whereas healthy volunteers did not experience nausea. We conclude that in a fasted condition, FD patients have a similar proximal gastric motor response to motilin as healthy volunteers, but experience an exaggerated sensation of nausea.