The probiotic fermented milk of Lacticaseibacillus paracasei JY062 and Lactobacillus gasseri JM1 alleviates constipation via improving gastrointestinal motility and gut microbiota

Constipation is directly related to the intestinal microenvironment, in which the promotion of gastrointestinal (GI) motility and improvement of gut microbiota distribution are important for alleviating symptoms. Herein, after the intervention of probiotic fermented milk (FMMIX) containing Lacticaseibacillus paracasei JY062 and Lactobacillus gasseri JM1 for 14 d in Kunming mice with loperamide-induced constipation, the results indicated that FMMIX significantly increased the secretion of serum motilin, gastrin and 5-hydroxytryptamine, as well as decreased the secretion of peptide YY, vasoactive intestinal peptide, and nitric oxide in mice. As determined by immunohistochemical analysis, FMMIX promoted an augmentation in the quantity of Cajal interstitial cells. In addition, the mRNA and protein expression of c-kit and stem cell factor (SCF) were upregulated to facilitate intestinal motility. High-throughput sequencing and gas chromatography techniques revealed that FMMIX led to an increase in the relative abundance of beneficial bacteria (Lactobacillus, Oscillospira, Ruminococcus, Coprococcus, and Akkermansia), reduced the presence of harmful bacteria (Prevotella), and resulted in elevated levels of short-chain fatty acids (SCFA) with a superior improvement compared with unfermented milk. Untargeted metabolomics revealed significant upregulation of functional metabolites such as l-pipecolinic acid, dl-phenylalanine, and naringenin in FMMIX, presumably playing a potential role in constipation relief. Overall, our results showed that FMMIX had the potential to alleviate constipation symptoms in mice by improving the secretion of serum GI regulatory peptides and neurotransmitters, increasing the expression of c-kit and SCF proteins, and modulating the gut microbiota structure and SCFA levels, and may be associated with an increase in these functional metabolites. This suggested that FMMIX could be a promising adjunctive strategy for managing constipation symptoms and could contribute to the development of functional foods aimed at improving gut health.

Alterations of Prostanoid Expression and Intestinal Epithelial Barrier Functions in Ileus

INTRODUCTION

Intestinal manipulation (IM)-induced inflammation could contribute to postoperative ileus (POI) pathophysiology via the modulation of prostanoid pathways. To identify the prostanoids involved, we aimed to characterize the profile of prostanoids and their synthesis enzyme expression in a murine model of POI and to determine whether the altered prostanoids could contribute to POI.

METHODS

Four or 14 h after IM in mice, gastrointestinal (GI) motility and intestinal epithelial barrier (IEB) permeability were assessed in vivo and ex vivo in Ussing chambers. Using high sensitivity liquid chromatography-tandem mass spectrometry, we characterized the tissue profile of polyunsaturated fatty acid metabolites in our experimental model. Finally, we evaluated in vivo the effects of the prostanoids studied upon IM-induced gut dysfunctions.

RESULTS

We first showed that 14 h after IM was significantly faster than jejunal transit at 4 h post-IM, although it remained significantly increased compared to the control. In contrast, we showed that IM-induced inflammation increase in jejunum permeability was similar after four and 14 h. We next showed that expression of prostacyclin synthase and hemopoietic prostaglandin-D synthase mRNA and their products were significantly reduced 14 h after IM as compared to controls. Furthermore, 15-deoxy-delta 12,14-Prostaglandin J2 reduced the IM-induced inflammation increase in IEB permeability but had no effect on GI motility. In contrast, PGI2 increased IM-induced IEB permeability and motility dysfunctions.

CONCLUSIONS

Arachidonic acid derivative contributes differentially to GI dysfunction in POI. The decrease of 15-deoxy-delta 12,14-Prostaglandin J2 levels induced by IM could contribute to impaired GI dysfunctions in POI and could be considered as putative therapeutic targets to restore barrier dysfunctions associated with POI.

Feasibility and repeatability of ultrasound-guided surface electroenterography to measure colonic slow wave motility in healthy adults

Surface electroenterography is a potential non-invasive alternative to current diagnostics of colonic motility disorders. However, electrode positioning in electroenterography is often based on general anatomy and may lack generalizability. Furthermore, the repeatability of electroenterography measurements is unknown. This study aimed to evaluate ultrasound-guided electrode positioning for electroenterography measurements and to determine the repeatability of those measurements. In ten healthy adults, two electroenterography procedures were performed, consisting of fasting, ultrasound-guided electrode localization and two 20-minute electroenterography recordings separated by a meal. The dominant frequency, the mean power density (magnitude of colonic motility) and the power percent difference (relative pre- to postprandial increase in magnitude) were determined. Repeatability was determined by Lin's concordance correlation coefficient. The results demonstrated that the dominant frequency did not differ between pre- and postprandial recordings and was 3 cpm, characteristic of colonic motility. The mean power density increased between the pre- and postprandial measurements, with an average difference of over 200%. The repeatability of both the dominant frequency and power density was poor to moderate, whereas the correlation coefficient of the power percent difference was poor. Concluding, ultrasound-guided surface electroenterography seems able to measure the gastrocolic reflex, but the dissatisfactory repeatability necessitates optimization of the measurement protocol.

Got the Munchies for an Egg Sandwich? The Effects of Cannabis on Bowel Motility and Beyond

The use of medicinal cannabis has a long history dating back thousands of years. Recent discoveries have shed light on its mechanism of action with the identification of cannabinoid receptors and endocannabinoids, which make up the body's endocannabinoid system. Cannabinoid receptors, particularly the cannabinoid 1 and 2 receptors, play a crucial role in modulating the gut-brain axis and serve as potential therapeutic targets for gastrointestinal motility and inflammatory disorders. With increasing legalization of cannabis and a rising number of users, understanding the effects of cannabis on gut motility is essential for nuclear medicine providers. Although tetrahydrocannabinol, the principal psychoactive constituent of cannabis, may decrease gut motility in experimental settings, it appears to paradoxically improve symptoms in gastroparesis. Treatment effects are difficult to measure given the large number of variables that could significantly alter outcomes, such as cannabinoid type, potency, and route of intake. Another consideration is the highly personalized gut microbiome, which directly interacts with the endocannabinoid system. Further research is required to delineate these multifaceted, complex cannabinoid interactions. The goal of this article is to explore the knowns and unknowns of the impact of cannabis on the alimentary system.

Nitric oxide and ion channels mediate L-cysteine-induced inhibition of colonic smooth muscle contraction

Previous studies have suggested that L-cysteine regulates gut motility through hydrogen sulfide. However, the mechanisms involved in the L-cysteine-induced response have not been extensively studied. This study aimed to investigate the underlying mechanisms of action of L-cysteine on spontaneous contraction of rat colon. Longitudinal and circular muscle strips from rat middle colon were prepared to measure the spontaneous contractile activities of colon in an organ bath system. Whole-cell voltage-clamp techniques were applied to record the currents of L-type voltage-dependent Ca2+ channels (VDCCs) and voltage-gated K+ channels (Kv) in isolated smooth muscle cells (SMCs) from colon. L-cysteine inhibited the spontaneous contraction of longitudinal and circular muscle strips from the rat colon in a concentration-dependent manner. The inhibition induced by L-cysteine was significantly decreased by inhibitors of H2S synthesis (p < 0.05). Furthermore, the suppression induced by L-cysteine was partially attenuated by tetrodotoxin, L-NNA and glibenclamide (p < 0.05). Whole-cell voltage-clamp recordings showed that L-cysteine caused a remarkable reduction in the peak currents of VDCCs and significantly increased the membrane currents of Kv channels in isolated SMCs (p < 0.05). We concluded that L-cysteine inhibits the contractile activities of smooth muscle strips from the rat colon. The relaxation in response to L-cysteine may be in part mediated by a nitrergic pathway and by inhibiting the VDCCs in combination with a direct activation of the KV channels and KATP channels.

Effect of abdominal hot pack application on gastrointestinal motility recovery after comprehensive gynecologic staging surgery

OBJECTIVE

To evaluate whether abdominal hot water pack application improves gastrointestinal motility following gynecological oncology surgery.

METHODS

The study was registered at ClinicalTrials.gov (NCT04833699). (https://clinicaltrials.gov/ct2/show/NCT04833699?cond=NCT04833699&draw=2&rank=1). In this randomized controlled trial, participants were randomly assigned (1:1) to the hot water pack group (standardized enhanced recovery protocols plus rubber water bag with a fluffy cover filled with boiled tap water [80°C] and placed on the abdomen at 3, 6, 9, and 12 h postoperatively for 30 min each time) or the control group (standardized enhanced recovery protocols). A subumbilical or supraumbilical vertical midline incision was made to perform staging surgery procedures, including hysterectomy, salpingo-oophorectomy with retroperitoneal lymphadenectomy. The primary outcome was the time to first passage of flatus from the end of the staging procedure.

RESULTS

In total, 121 women were randomized to the control (n = 62) or hot water pack (n = 59) group. The use of an abdominal hot water pack significantly reduced the mean time to passing first flatus (25.2 ± 3.6 vs. 30.6 ± 3.9 h; hazard ratio [HR] = 4.4; 95% confidence interval [CI]: 2.8-7.1; P < 0.0001), mean time to first bowel movements (28.4 ± 4.0 vs. 34.4 ± 4.5 h; HR = 4.9; 95% CI: 3.0-7.9; P < 0.0001), mean time to first defecation (33.4 ± 4.9 vs. 41.0 ± 7.6 h; HR = 4.3; 95% CI: 2.1-6.8; P < 0.0001), and mean time to tolerating solid diet (2.1 ± 0.6 vs. 2.8 ± 1.0 days; HR = 4.4; 95% CI: 2.2-8.7; P < 0.0001) compared to the control group. The postoperative ileus incidence was significantly lower in the hot water pack group (3.4%) than the control group (16.1%) (P = 0.01).

CONCLUSION

Abdominal hot water pack application improved gastrointestinal function recovery in women following surgical staging procedures for gynecological malignancy.

Diagnostic and therapeutic approach to children with chronic refractory constipation: Consensus report by the SIGENP motility working group

Constipation is a common problem in children, accounting for about 3% of all primary care visits and up to 25% of referrals to paediatric gastroenterologists. Although polyethylene glycol often proves effective, most children require prolonged treatment and about 50% of them have at least one relapse within the first 5 years after initial recovery. When conventional treatment fails, children are considered to have refractory constipation. Children with refractory constipation deserve specialist management and guidance. Over the last decades, there has been a remarkable increase in our knowledge of normal and abnormal colonic and anorectal motility in children, and a number of different techniques to measure transit and motility have been developed. The present review analyses the possible diagnostic investigations for children with refractory constipation, focusing on their actual indications and their utility in clinical practice. Moreover, we have also analytically reviewed medical and surgical therapeutic options, which should be considered in selected patients in order to achieve the best clinical outcome.

The role of free fatty acid receptor-1 in gastric contractions in Suncus murinus

Motilin is an important hormonal regulator in the migrating motor complex (MMC). Free fatty acid receptor-1 (FFAR1, also known as GPR40) has been reported to stimulate motilin release in human duodenal organoids. However, how FFAR1 regulates gastric motility in vivo is unclear. This study investigated the role of FFAR1 in the regulation of gastric contractions and its possible mechanism of action using Suncus murinus. Firstly, intragastric administration of oleic acid (C18:1, OA), a natural ligand for FFAR1, stimulated phase II-like contractions, followed by phase III-like contractions in the fasted state, and the gastric emptying rate was accelerated. The administration of GW1100, an FFAR1 antagonist, inhibited the effects of OA-induced gastric contractions. Intravenous infusion of a ghrelin receptor antagonist (DLS) or serotonin 4 (5-HT4) receptor antagonist (GR125487) inhibited phase II-like contractions and prolonged the onset of phase III-like contractions induced by OA. MA-2029, a motilin receptor antagonist, delayed the occurrence of phase III-like contractions. In vagotomized suncus, OA did not induce phase II-like contractions. In addition, OA promoted gastric emptying through a vagal pathway during the postprandial period. However, OA did not directly act on the gastric body to induce contractions in vitro. In summary, this study indicates that ghrelin, motilin, 5-HT, and the vagus nerve are involved in the role of FFAR1 regulating MMC. Our findings provide novel evidence for the involvement of nutritional factors in the regulation of gastric motility.

A hydrolyzed casein diet promotes Ngn3 controlling enteroendocrine cell differentiation to increase gastrointestinal motility in mice

Gut hormones are produced by enteroendocrine cells (EECs) found along the intestinal epithelium, and these cells play a crucial role in regulating intestinal function, nutrient absorption and food intake. A hydrolyzed casein diet has been reported to promote the secretion of gut hormones through the regulation of EEC development, but the underlying mechanism remains unclear. Therefore, this study was conducted to investigate whether the hydrolyzed casein diet can regulate EEC differentiation by employing mouse and organoid models. Mice were fed diets containing either casein (casein group) or hydrolyzed casein (hydrolyzed casein group) as the sole protein source. The hydrolyzed casein diet upregulated the expression of transcription factors, induced EEC differentiation, increased fasting serum ghrelin concentrations and promoted gastrointestinal (GI) motility in the duodenum compared to the casein diet. Interestingly, these differences could be abolished when there is addition of antibiotics to the drinking water, suggesting a significant role of gut microbiota in the hydrolyzed casein-mediated EEC function. Further investigation showed that the hydrolyzed casein diet led to reduced microbial diversity, especially the abundance of Akkermansia muciniphila (A. muciniphila) on the duodenal mucosa. In contrast, gavage with A. muciniphila impaired EEC differentiation through attenuated neurog3 transcription factor (Ngn3) expression, mediated through the promotion of Notch signaling. Moreover, pasteurized A. muciniphila showed similar effects to enter organoids in vitro. Overall, we found that a hydrolyzed casein diet reduced the abundance of A. muciniphila and promoted Ngn3 controlling EEC differentiation and this pathway is associated with increased GI motility in mice. The findings provide new insights into the role of hydrolyzed casein in gut transit and guidelines for using hydrolyzed casein in safe formula milk.

Does Chewing Gum Lead to Earlier Postoperative Gastrointestinal Recovery in Children? A Systematic Review and Meta-analysis

INTRODUCTION

Postoperative ileus is a common occurrence among children undergoing major operations, including gastrointestinal and spinal surgeries. Preliminary evidence in adults suggests that chewing gum plays a role in accelerating the return of postoperative gastrointestinal function. However, evidence is scarce in the paediatric population. The aim of this study was to investigate whether chewing gum has benefits for children.

METHODS

We searched PubMed, Medline, Embase, and Cochrane Trials databases for randomised controlled trials that compare gum chewing with standard care after elective surgery in children from 1st Jan 2005 to 31st July 2021. We assessed the identified trials for quality and performed a systematic review and meta-analysis in accordance with PRISMA and registered in PROSPERO (CRD42022358801). The main outcome measures examined were time to flatus and stool postoperatively, time to tolerate oral intake, and length of hospital stay, which were analysed using fixed effects models. We also examined clinical complication rates and postoperative pain control.

RESULTS

We included six eligible trials, with a total of 357 enrolled patients. The intervention was well tolerated without complications. There was no significant difference in time to flatus (-2.86 h; 95 % CI: -6.2 to 0.47 h, p = 0.09), time to stool (-6.39 h; 95 % CI: -13.9 to 1.2 h, p = 0.1), time to tolerate oral intake (-0.03 days; 95 % CI: -0.15 to 0.1 days, p = 0.68), and length of hospital stay (0.08 days; 95 % CI: -0.07 to 0.22 days, p = 0.29). Postoperative pain control (opioid consumption, pain score, nausea score) was similar in both groups (p > 0.05).

CONCLUSION

Current evidence demonstrates that gum chewing is not associated with earlier postoperative gastrointestinal recovery in children. Future adequately powered and well-designed trials are necessary to evaluate any clinical benefit of chewing gum for children and whether it could result differences in healthcare satisfaction.

LEVEL OF EVIDENCE

I.

Current insights on chronic intestinal dysmotility: pseudo-obstruction and enteric dysmotility

Chronic intestinal dysmotility is a rare and debilitating digestive disorder characterized by symptoms of mechanical obstruction without an organic lesion. It has diverse causes and involves various pathological mechanisms. Small bowel manometry is the preferred diagnostic method, particularly for patients with severe and progressive symptoms. The condition can be categorized as intestinal pseudo-obstruction and enteric dysmotility, both entities share abnormal small bowel motility, but with important differences in prognosis and management.

Research progress on mechanism of acupuncture in treating functional constipation

Acupuncture treatment for functional constipation (FC) is characterized by precise efficacy, rapid onset of action in the early stages, long-term stable effects, and overall regulation. This paper reviews recent literatures on acupuncture treatment for FC, indicating that acupuncture acts from multiple perspectives and pathways, including promoting intestinal motility, regulating intestinal microbiota, modulating the brain-gut axis, alleviating intestinal inflammation, and improving rectal hyposensitivity. Future research could delve into the mechanical sensation conduction mechanisms of acupuncture in improving rectal hyposensitivity, identify key intestinal microbiota genera and metabolic characteristics regulated by acupuncture, explore the network relationships among different mechanisms, and clarify the differential mechanisms of various acupuncture treatment protocols to optimize clinical therapy and enhance the clinical efficacy of acupuncture for FC.

Molecular mechanisms of cholinergic neurotransmission in visceral smooth muscles with a focus on receptor-operated TRPC4 channel and impairment of gastrointestinal motility by general anaesthetics and anxiolytics

Acetylcholine is the primary excitatory neurotransmitter in visceral smooth muscles, wherein it binds to and activates two muscarinic receptors subtypes, M2 and M3, thus causing smooth muscle excitation and contraction. The first part of this review focuses on the types of cells involved in cholinergic neurotransmission and on the molecular mechanisms underlying acetylcholine-induced membrane depolarisation, which is the central event of excitation-contraction coupling causing Ca2+ entry via L-type Ca2+ channels and smooth muscle contraction. Studies of the muscarinic cation current in intestinal myocytes (mICAT) revealed its main molecular counterpart, receptor-operated TRPC4 channel, which is activated in synergy by both M2 and M3 receptors. M3 receptors activation is of permissive nature, while activation of M2 receptors via Gi/o proteins that are coupled to them plays a direct role in TRPC4 opening. Our understanding of signalling pathways underlying mICAT generation has vastly expanded in recent years through studies of TRPC4 gating in native cells and its regulation in heterologous cells. Recent studies using muscarinic receptor knockout have established that at low agonist concentration activation of both M2 receptor and the M2/M3 receptor complex elicits smooth muscle contraction, while at high agonist concentration M3 receptor function becomes dominant. Based on this knowledge, in the second part of this review we discuss the cellular and molecular mechanisms underlying the numerous anticholinergic effects on neuroactive drugs, in particular general anaesthetics and anxiolytics, which can significantly impair gastrointestinal motility. This article is part of the Special Issue on "Ukrainian Neuroscience".

The critical role of muscularis macrophages in modulating the enteric nervous system function and gastrointestinal motility

Macrophages are the originators of inflammatory compounds, phagocytic purifiers in their local environment, and wound healing protectors in oxidative environments. They are molded by the tissue milieu they inhabit, with gastrointestinal (GI) muscularis macrophages (MMs) being a prime example. MMs are located in the muscular layer of the GI tract and contribute to muscle repair and maintenance of GI motility. MMs are often in close proximity to the enteric nervous system, specifically near the enteric neurons and interstitial cells of Cajal (ICCs). Consequently, the anti-inflammatory function of MMs corresponds to the development and maintenance of neural networks in the GI tract. The capacity of MMs to shift from anti-inflammatory to proinflammatory states may contribute to the inflammatory aspects of various GI diseases and disorders such as diabetic gastroparesis or postoperative ileus, functional disorders such as irritable bowel syndrome, and organic diseases such as inflammatory bowel disease. We reviewed the current knowledge of MMs and their influence on neighboring cells due to their important role in the GI tract.

Age-associated changes in lineage composition of the enteric nervous system regulate gut health and disease

The enteric nervous system (ENS), a collection of neural cells contained in the wall of the gut, is of fundamental importance to gastrointestinal and systemic health. According to the prevailing paradigm, the ENS arises from progenitor cells migrating from the neural crest and remains largely unchanged thereafter. Here, we show that the lineage composition of maturing ENS changes with time, with a decline in the canonical lineage of neural-crest derived neurons and their replacement by a newly identified lineage of mesoderm-derived neurons. Single cell transcriptomics and immunochemical approaches establish a distinct expression profile of mesoderm-derived neurons. The dynamic balance between the proportions of neurons from these two different lineages in the post-natal gut is dependent on the availability of their respective trophic signals, GDNF-RET and HGF-MET. With increasing age, the mesoderm-derived neurons become the dominant form of neurons in the ENS, a change associated with significant functional effects on intestinal motility which can be reversed by GDNF supplementation. Transcriptomic analyses of human gut tissues show reduced GDNF-RET signaling in patients with intestinal dysmotility which is associated with reduction in neural crest-derived neuronal markers and concomitant increase in transcriptional patterns specific to mesoderm-derived neurons. Normal intestinal function in the adult gastrointestinal tract therefore appears to require an optimal balance between these two distinct lineages within the ENS.

Does ghrelin regulate intestinal motility in rabbits? An in vitro study using isolated duodenal strips

Rabbit duodenum has been used for examining the ability of motilin to cause muscle contraction in vitro. A motilin-related peptide, ghrelin, is known to be involved in the regulation of gastrointestinal (GI) motility in various animals, but its ability to cause rabbit GI contraction have not been well examined. The aim of this study is to clarify the action of rat ghrelin and its interaction with motilin in the rabbit duodenum. The mRNA expression of ghrelin and motilin receptors was also examined using RT-PCR. Rat ghrelin (10-9-10-6 M) did not change the contractile activity of the duodenum measured by the mean muscle tonus and area under the curve of contraction waves. In agreement with this result, the distribution of ghrelin receptor mRNA in the rabbit GI tract varied depending on the GI region from which the samples were taken; the expression level in the duodenum was negligible, but that in the esophagus or stomach was significant. On the other hand, motilin (10-10-10-6 M) caused a concentration-dependent contraction by means of increased mean muscle tonus, and consistently, motilin receptor mRNA was expressed heterogeneously depending on the GI region (esophagus = stomach = colon = rectum < duodenum = jejunum = ileum < cecum). Expression level of motilin receptor was comparable to that of ghrelin receptor in the esophagus and stomach. Pretreatment with ghrelin (10-6 M) prior to motilin did not affect the contractile activity of motilin in the duodenum. In conclusion, ghrelin does not affect muscle contractility or motilin-induced contraction in the rabbit duodenum, which is due to the lack of ghrelin receptors. The present in vitro results suggest that ghrelin might not be a regulator of intestinal motility in rabbits.

Small Bowel Transit Scintigraphy in Children With Pediatric Intestinal Pseudo-Obstruction

INTRODUCTION

Objective evidence of small intestinal dysmotility is a key criterion for the diagnosis of pediatric intestinal pseudo-obstruction (PIPO). Small bowel scintigraphy (SBS) allows for objective measurement of small bowel transit (SBT), but limited data are available in children. We aimed to evaluate the utility of SBS in children suspected of gastrointestinal dysmotility.

METHODS

Patients undergoing gastric emptying studies for suspected foregut dysmotility, including PIPO, from 2016 to 2022 at 2 tertiary children's hospitals were recruited to an extended protocol of gastric emptying studies to allow for assessment of SBT. PIPO was classified based on antroduodenal manometry (ADM). SBT was compared between PIPO and non-PIPO patients. Scintigraphic parameters were assessed and correlated against ADM scores.

RESULTS

Fifty-nine patients (16 PIPO and 43 non-PIPO diagnoses) were included. SBS was performed with liquid and solid meals in 40 and 26 patients, respectively. As compared to the non-PIPO group, PIPO patients had a significantly lower median percentage of colonic filling at 6 hours, with both liquid (48% vs 83%) and solid tests (5% vs 65%). SBT in PIPO patients with myopathic involvement was significantly slower than in patients with neuropathic PIPO, both for liquid and solid meal. A significant correlation was found between solid SBT and ADM scores (r = -0.638, P = 0.036).

DISCUSSION

SBS provides a practically feasible assessment of small intestinal motility. It shows a potential utility to help diagnose and characterize PIPO. SBS seems most discriminative in PIPO patients with myopathic involvement. Studies in a larger pediatric population and across different ages are required.

Plant-based meat analogues enhance the gastrointestinal motility function and appetite of mice by specific volatile compounds and peptides

Eating behavior is critical for maintaining energy homeostasis. Previous studies have found that plant-based meat analogues increased diet intake in mice compared with animal meat under a free feeding mode, however the reasons were unclear. To explore the underlying mechanisms of plant-based meat analogues increasing diet intake, mice were fed animal or plant-based pork and beef analogue diets, respectively. Biochemical and histological analyses were performed to evaluate appetite-regulating hormones and gastrointestinal motility function. Peptiomics and GC-IMS were applied to identify key substances. We found that the intake of plant-based meat analogues significantly enhanced the gastrointestinal motility function of mice. The long-term intake (68 days) of plant-based meat analogues significantly increased the muscle layer thickness of the duodenum and jejunum of mice; the activity of gastrointestinal cells of Cajal were also promoted by upregulating the expression of c-kit related signals as compared to animal meat; plant-based meat analogues intake markedly enhanced the signal intensity of the intestinal neurotransmitter 5-hydroxytryptamine (5-HT) by upregulating the expression of 5-HT synthase and receptors but downregulating its transporter and catabolic enzyme in the intestine. Moreover, plant-based meat analogues intake significantly increased levels of appetite-stimulating factors in the peripheral or hypothalamus but reduced levels of appetite-suppressing factors compared with animal meat. Specific volatile compounds were significantly associated with appetite regulating factors. Among them, 7 substances such as linalool have a potential promoting effect on food intake. Besides, different digestive peptides in gastrointestinal tract may affect eating behavior mainly through the neuroactive ligand-receptor interaction pathway, exerting hormone-like effects or influencing endocrine cell secretion. These findings preliminarily clarified the mechanism of plant-based meat analogues promoting diet intake and provided a theoretical basis for a reasonable diet.

Pico145 inhibits TRPC4-mediated mICAT and postprandial small intestinal motility

In intestinal smooth muscle cells, receptor-operated TRPC4 are responsible for the majority of muscarinic receptor cation current (mICAT), which initiates cholinergic excitation-contraction coupling. Our aim was to examine the effects of the TRPC4 inhibitor Pico145 on mICAT and Ca2+ signalling in mouse ileal myocytes, and on intestinal motility. Ileal myocytes freshly isolated from two month-old male BALB/c mice were used for patch-clamp recordings of whole-cell currents and for intracellular Ca2+ imaging using Fura-2. Functional assessment of Pico145's effects was carried out by standard in vitro tensiometry, ex vivo video recordings and in vivo postprandial intestinal transit measurements using carmine red. Carbachol (50 µM)-induced mICAT was strongly inhibited by Pico145 starting from 1 pM. The IC50 value for the inhibitory effect of Pico145 on this current evoked by intracellularly applied GTPγS (200 µM), and thus lacking desensitisation, was found to be 3.1 pM, while carbachol-induced intracellular Ca2+ rises were inhibited with IC50 of 2.7 pM. In contrast, the current activated by direct TRPC4 agonist (-)-englerin A was less sensitive to the action of Pico145 that caused only ∼43 % current inhibition at 100 pM. The inhibitory effect developed rather slowly and it was potentiated by membrane depolarisation. In functional assays, Pico145 produced concentration-dependent suppression of both spontaneous and carbachol-evoked intestinal smooth muscle contractions and delayed postprandial intestinal transit. Thus, Pico145 is a potent GI-active small-molecule which completely inhibits mICAT at picomolar concentrations and which is as effective as trpc4 gene deficiency in in vivo intestinal motility tests.

Effects of Multiple High-Dose Methamphetamine Administration on Enteric Dopaminergic Neurons and Intestinal Motility in the Rat Model

Several studies have identified the effects of methamphetamine (MA) on central dopaminergic neurons, but its effects on enteric dopaminergic neurons (EDNs) are unclear. The aim of this study was to investigate the effects of MA on EDNs and intestinal motility. Male Sprague-Dawley rats were randomly divided into MA group and saline group. The MA group received the multiple high-dose MA treatment paradigm, while the controls received the same saline treatment. After enteric motility was assessed, different intestinal segments (i.e., duodenum, jejunum, ileum, and colon) were taken for histopathological, molecular biological, and immunological analysis. The EDNs were assessed by measuring the expression of two dopaminergic neuronal markers, dopamine transporter (DAT) and tyrosine hydroxylase (TH), at the transcriptional and protein levels. We also used c-Fos protein, a marker of neural activity, to detect the activation of EDNs. MA resulted in a significant reduction in TH and DAT mRNA expression as well as in the number of EDNs in the duodenum and jejunum (p < 0.05). MA caused a dramatic increase in c-Fos expression of EDNs in the ileum (p < 0.001). The positional variability of MA effects on EDNs paralleled the positional variability of its effect on intestinal motility, as evidenced by the marked inhibitory effect of MA on small intestinal motility (p < 0.0001). This study found significant effects of MA on EDNs with locational variability, which might be relevant to locational variability in the potential effects of MA on intestinal functions, such as motility.

Abnormal gastrointestinal motility is a major factor in explaining symptoms and a potential therapeutic target in patients with disorders of gut-brain interaction

The objective of this article is to review the evidence of abnormal gastrointestinal (GI) tract motor functions in the context of disorders of gut-brain interaction (DGBI). These include abnormalities of oesophageal motility, gastric emptying, gastric accommodation, colonic transit, colonic motility, colonic volume and rectal evacuation. For each section regarding GI motor dysfunction, the article describes the preferred methods and the documented motor dysfunctions in DGBI based on those methods. The predominantly non-invasive measurements of gut motility as well as therapeutic interventions directed to abnormalities of motility suggest that such measurements are to be considered in patients with DGBI not responding to first-line approaches to behavioural or empirical dietary or pharmacological treatment.

Modulation of Intestinal Motility in an Adolescent Rat Model of Irritable Bowel Syndrome

INTRODUCTION

The pathophysiology of irritable bowel syndrome (IBS) remains unknown. This study aimed to evaluate colonic motility and serotonin system response to restraint stress (RS) among adolescent rats who underwent neonatal maternal separation (NMS) to clarify the features of pathogenesis in adolescents with IBS.

METHODS

Male rats were exposed to NMS as chronic stress, and a normally handled (NH) group was used as control. Four groups were created by adding RS as acute stress treatment to the NMS and NH groups. To realize the RS treatment, the subjects were restrained for 1 h at the age of 5 weeks, and hourly fecal pellet discharge was determined. After euthanization and proximal colon intestinal tissue collection, 5-hydroxytryptamine (5-HT) and 5-hydroxytryptamine receptor 3 (5-HT3R) concentrations, enterochromaffin (EC) cell density, and the expression of mRNA-encoding slc6a4 were examined.

RESULTS

The amount of fecal pellet discharge during RS increased significantly in the RS and NMS+RS groups compared with that in the NH and NMS groups, respectively. The 5-HT concentration in the intestinal tissue of rats in the RS and NMS groups increased significantly compared with that of rats in the NH group. EC cell density also increased significantly in the NMS and NMS+RS groups compared with that in the NH and RS groups. However, combined stress did not result in any significant differences in the expression of 5-HT3R and mRNA-encoding slc6a4.

CONCLUSIONS

The combination of juvenile and acute stress effectively induced increased 5-HT concentration or EC cell density via the 5-HT pathway in the proximal colon of adolescent rats.

Differences in intestinal motility during different sleep stages based on long-term bowel sounds

BACKGROUND AND OBJECTIVES

This study focused on changes in intestinal motility during different sleep stages based on long-term bowel sounds.

METHODS

A modified higher order statistics algorithm was devised to identify the effective bowel sound segments. Next, characteristic values (CVs) were extracted from each bowel sound segment, which included 4 time-domain, 4 frequency-domain and 2 nonlinear CVs. The statistical analysis of these CVs corresponding to the different sleep stages could be used to evaluate the changes in intestinal motility during sleep.

RESULTS

A total of 6865.81 min of data were recorded from 14 participants, including both polysomnographic data and bowel sound data which were recorded simultaneously from each participant. The average accuracy, sensitivity and specificity of the modified higher order statistics detector were 96.46 ± 2.60%, 97.24 ± 2.99% and 94.13 ± 4.37%. In addition, 217088 segments of effective bowel sound corresponding to different sleep stages were identified using the modified detector. Most of the CVs were statistically different during different sleep stages ([Formula: see text]). Furthermore, the bowel sounds were low in frequency based on frequency-domain CVs, high in energy based on time-domain CVs and low in complexity base on nonlinear CVs during deep sleep, which was consistent with the state of the EEG signals during deep sleep.

CONCLUSIONS

The intestinal motility varies by different sleep stages based on long-term bowel sounds using the modified higher order statistics detector. The study indicates that the long-term bowel sounds can well reflect intestinal motility during sleep. This study also demonstrates that it is technically feasible to simultaneously record intestinal motility and sleep state throughout the night. This offers great potential for future studies investigating intestinal motility during sleep and related clinical applications.

Effects of electroacupuncture combined with acupoint catgut embedding on gastrointestinal motility and gastrointestinal hormones in rats with functional dyspepsia

Electroacupuncture (EA) or acupoint catgut embedding (ACE) plays a therapeutic role in functional dyspepsia (FD). Herein, we aimed to elucidate the influences of EA combined with ACE on gastrointestinal motility and gastrointestinal hormones in rats with FD. Sprague-Dawley rats were randomized into the control group, model group, EA group, ACE group, and EA + ACE group (n = 10). Except for the control group, the rats in all groups were modeled by combining neonatal iodoacetamide gastrogavage and modified tail-clamping stimulation. The rats were treated with different treatments according to their groups. The rats were observed for changes in general behavior, body weight, food intake, and paw mechanical pain threshold. Gastric emptying rate (GER) and intestinal propulsive ratio (IPR) were measured in each group, and serum gastrointestinal hormone (motilin [MTL], leptin, gastrin [GAS], vasoactive intestinal peptide [VIP], calcitonin gene-related peptide [CGRP], and somatostatin [SS]) levels, oxidative stress factors (superoxide dismutase [SOD] and malondialdehyde [MDA]) and 5-hydroxytryptamine (5-HT) levels were also measured. Decreased mean body weight, paw mechanical pain thresholds, food intake, and GER and IPR were found in rats of the model group in comparison to the control group. Serum MTL, GAS, SS, and SOD levels were reduced, and serum leptin, VIP, CGRP, MDA, and 5-HT levels were increased in rats of the model group in comparison to the control group. Elevated mean body weight, paw mechanical pain threshold, food intake, GER and IPR, and serum MTL, GAS, SS, and SOD levels, and reduced serum leptin, VIP, CGRP, MDA, and 5-HT levels were observed in rats of the EA, ACE, and EA + ACE groups relative to the model group. EA combined with ACE treatment was more effective than the EA or ACE treatment alone. EA combined with ACE treatment improves gastrointestinal motility and gastrointestinal hormone levels, promotes food intake, and reduces visceral hypersensitivity in FD rats.

Technical Feasibility of Quantitative Measurement of Various Degrees of Small Bowel Motility Using Cine Magnetic Resonance Imaging

OBJECTIVE

Cine magnetic resonance imaging (MRI) has emerged as a noninvasive method to quantitatively assess bowel motility. However, its accuracy in measuring various degrees of small bowel motility has not been extensively evaluated. We aimed to draw a quantitative small bowel motility score from cine MRI and evaluate its performance in a population with varying degrees of small bowel motility.

MATERIALS AND METHODS

A total of 174 participants (28.5 ± 7.6 years; 135 males) underwent a 22-second-long cine MRI sequence (2-dimensional balanced turbo-field echo; 0.5 seconds per image) approximately 5 minutes after being intravenously administered 10 mg of scopolamine-N-butyl bromide to deliberately create diverse degrees of small bowel motility. In a manually segmented area of the small bowel, motility was automatically quantified using a nonrigid registration and calculated as a quantitative motility score. The mean value (MV) of motility grades visually assessed by two radiologists was used as a reference standard. The quantitative motility score's correlation (Spearman's ρ) with the reference standard and performance (area under the receiver operating characteristics curve [AUROC], sensitivity, and specificity) for diagnosing adynamic small bowel (MV of 1) were evaluated.

RESULTS

For the MV of the quantitative motility scores at grades 1, 1.5, 2, 2.5, and 3, the mean ± standard deviation values were 0.019 ± 0.003, 0.027 ± 0.010, 0.033 ± 0.008, 0.032 ± 0.009, and 0.043 ± 0.013, respectively. There was a significant positive correlation between the quantitative motility score and the MV (ρ = 0.531, P < 0.001). The AUROC value for diagnosing a MV of 1 (i.e., adynamic small bowel) was 0.953 (95% confidence interval, 0.923-0.984). Moreover, the optimal cutoff for the quantitative motility score was 0.024, with a sensitivity of 100% (15/15) and specificity of 89.9% (143/159).

CONCLUSION

The quantitative motility score calculated from a cine MRI enables diagnosis of an adynamic small bowel, and potentially discerns various degrees of bowel motility.

Effect of Acupoint Stimulation on Improving Gastrointestinal Motility in Patients After Gastrectomy: A Systematic Review and Meta-Analysis

Introduction: Gastrointestinal immobility is experienced by many patients who undergo gastric surgery. This complication delays enteral nutrition, prolongs hospitalization, and causes discomfort. Acupoint stimulation is a popular alternative nonpharmacological treatment for gastrointestinal immobility. This study aimed to explore the effects of acupoint stimulation on gastrointestinal immobility after gastrectomy. Design: Systematic review and meta-analysis. Methods: Databases (PubMed, Cochrane, Joanna Briggs Institute EBP Database, Medline, CINAHL Complete, and Airiti library) were searched from their inception to April 2022 for relevant articles. Articles in Chinese and English were included, without limitations on year, region, or country. The inclusion criteria were studies with participants >18 years of age, postgastric surgery, and hospitalization. In addition, randomized controlled trials (RCTs) were included. Data were analyzed using random effects models, and data heterogeneity was investigated using subgroup analysis. Meta-analysis was performed using Review Manager 5.4 software. Results: We included 785 participants from six studies. Invasive and noninvasive acupoint stimulation reduced the time of gastrointestinal mobility better than usual care. In the control group, the time of first flatus was 43.56 ± 9.57 h to 108 ± 19.2 h, and the time of first defecation was 77.27 ± 22.67 h to 139.2 ± 24 h. In the experimental group, the time of first flatus and defecation was 36.58 ± 10.75 h to 79.97 ± 37.31 h and 70.56 ± 15.36 h to 108.55 ± 10.75 h, respectively. Subgroup analysis showed that invasive acupoint stimulation with acupuncture reduced the time of first flatus and defecation to 15.03 h (95% confidence interval [CI] = -31.06 to 1.01) and 14.12 h (95% CI = -32.78 to 4.54), respectively. Noninvasive acupoint stimulation, including acupressure and transcutaneous electrical acupoint stimulation (TEAS), reduced the time of first flatus and defecation to 12.33 h and (95% CI = -20.59 to -4.06) and 12.20 h (95% CI = -24.92 to 0.52), respectively. Conclusions: Acupoint stimulation improved the gastrointestinal immobility of postgastrectomy. In the included RCT articles, invasive and noninvasive stimulations were effective. However, noninvasive acupoint stimulation, such as with TEAS and acupressure, was more efficient and convenient than invasive stimulation. Overall, health care professionals with adequate training or under the supervision of an acupuncturist can effectively perform acupoint stimulation to improve the quality of postgastrectomy care. They can select commonly used and effective acupoints to enhance gastrointestinal motility. Clinical relevance: Acupoint stimulation, such as acupressure, electrical acupoint stimulation, or acupuncture, can be included in postgastrectomy routine care to improve gastrointestinal motility and reduce abdominal discomfort.

Neural targets of the enteric dopaminergic system in regulating motility of rat proximal colon

In isolated segments of the rat proximal colon, the dopamine reuptake inhibitor GBR 12909 (GBR) causes a dilatation, while the D1-like receptor antagonist SCH 23390 (SCH) induces a tonic constriction, suggesting that neurally released dopamine tonically stimulates enteric inhibitory efferent neurons. Here, the targets of the enteric dopaminergic neurons were investigated. Cannulated segments of rat proximal colon were bathed in physiological salt solution and luminally perfused with 0.9% saline, while all drugs were applied to the bath. Spatio-temporal maps of colonic motility were constructed from video recordings of peristaltic contractions, and the maximum diameter was measured as an index of colonic contractility. GBR (1 μM)-induced dilatations of colonic segments were prevented by SCH (5 μM), L-nitro arginine (L-NA; 100 μM), a nitric oxide synthase inhibitor, or tetrodotoxin (0.6 μM). In contrast, constrictions induced by a higher concentration of SCH (20 μM) were unaffected by either L-NA or tetrodotoxin. The vasoactive intestinal peptide (VIP) receptor antagonist VIP10-28 (3 μM) or P2Y1 receptor antagonist MRS 2500 (1 μM) had no effect on either the GBR-induced dilatation or the SCH-induced constriction. In colonic segments that had been pretreated with 6-hydroxydopamine (100 μM, 3 h) to deplete enteric dopamine, GBR failed to increase the colonic diameter, while SCH was still capable of constricting colonic segments. Enteric dopaminergic neurons appear to project to nitrergic neurons to dilate the proximal colon by activating neuronal D1-like receptors. In addition, constitutively activated D1-like receptors expressed in cells yet to be determined may provide a tonic inhibition on colonic constrictions.

Astaxanthin attenuated the stress-induced intestinal motility disorder via altering the gut microbiota

Gut microbiota and short-chain fatty acids (SCFAs) are recognized as key factors in the pathophysiology of irritable bowel syndrome. Astaxanthin is a carotenoid with strong antioxidant and anti-inflammatory activities. In this study, we examined the effects of astaxanthin on gut microbiota-, SCFAs-, and corticotropin-releasing factor (CRH)-induced intestinal hypermotility. Male Wistar rats (n=12 per group) were fed a diet with or without 0. 02% (w/w) astaxanthin for four weeks and CRH or saline was administered intravenously. The number of fecal pellets was counted 2 h after injection. Then the rats were sacrificed, and the cecal content were collected 3 h after injection. The number of feces was significantly increased by CRH injection in the control group (2.0 vs. 6.5; p=0.028), but not in the astaxanthin group (1.0 vs. 2.2; p=0.229) (n=6 per group). The cecal microbiota in the astaxanthin group was significantly altered compared with that in the control group. The concentrations of acetic acid (81.1 μmol/g vs. 103.9 μmol/g; p=0.015) and butyric acid (13.4 μmol/g vs. 39.2 μmol/g; p<0.001) in the astaxanthin group were significantly lower than that in the control group (n=12 per group). Astaxanthin attenuates CRH-induced intestinal hypermotility and alters the composition of gut microbiota and SCFAs.

BQ788 reveals glial ETB receptor modulation of neuronal cholinergic and nitrergic pathways to inhibit intestinal motility: Linked to postoperative ileus

BACKGROUND AND PURPOSE

ET-1 signalling modulates intestinal motility and inflammation, but the role of ET-1/ETB receptor signalling is poorly understood. Enteric glia modulate normal motility and inflammation. We investigated whether glial ETB signalling regulates neural-motor pathways of intestinal motility and inflammation.

EXPERIMENTAL APPROACH

We studied ETB signalling using: ETB drugs (ET-1, SaTX, BQ788), activity-dependent stimulation of neurons (high K+ -depolarization, EFS), gliotoxins, Tg (Ednrb-EGFP)EP59Gsat/Mmucd mice, cell-specific mRNA in Sox10CreERT2 ;Rpl22-HAflx or ChATCre ;Rpl22-HAflx mice, Sox10CreERT2 ::GCaMP5g-tdT, Wnt1Cre2 ::GCaMP5g-tdT mice, muscle tension recordings, fluid-induced peristalsis, ET-1 expression, qPCR, western blots, 3-D LSM-immunofluorescence co-labelling studies in LMMP-CM and a postoperative ileus (POI) model of intestinal inflammation.

KEY RESULTS

In the muscularis externa ETB receptor is expressed exclusively in glia. ET-1 is expressed in RiboTag (ChAT)-neurons, isolated ganglia and intra-ganglionic varicose-nerve fibres co-labelled with peripherin or SP. ET-1 release provides activity-dependent glial ETB receptor modulation of Ca2+ waves in neural evoked glial responses. BQ788 reveals amplification of glial and neuronal Ca2+ responses and excitatory cholinergic contractions, sensitive to L-NAME. Gliotoxins disrupt SaTX-induced glial-Ca2+ waves and prevent BQ788 amplification of contractions. The ETB receptor is linked to inhibition of contractions and peristalsis. Inflammation causes glial ETB up-regulation, SaTX-hypersensitivity and glial amplification of ETB signalling. In vivo BQ788 (i.p., 1 mg·kg-1 ) attenuates intestinal inflammation in POI.

CONCLUSION AND IMPLICATIONS

Enteric glial ET-1/ETB signalling provides dual modulation of neural-motor circuits to inhibit motility. It inhibits excitatory cholinergic and stimulates inhibitory nitrergic motor pathways. Amplification of glial ETB receptors is linked to muscularis externa inflammation and possibly pathogenic mechanisms of POI.

Optimization of Gastric Pacing Parameters Using High-Resolution Mapping

OBJECTIVE

Abnormal slow-wave activity has been associated with functional motility disorders. Gastric pacing has been investigated to correct slow-wave abnormalities, but clinical therapies are yet to be established. This study aimed to define optimal parameters to advance the application of gastric pacing.

METHODS

High-resolution gastric mapping was utilized to evaluate four pacing parameters in in-vivo pig studies: (i) orientation of the pacing electrodes (longitudinal vs circumferential), (ii) pacing energy (900 vs 10,000 ms mA2), (iii) the pacing location (corpus vs antrum), and (iv) pacing period (between 12 and 36 s).

RESULTS

The probability of slow-wave initiation and entrainment with the pacing electrodes oriented longitudinally was significantly higher than with electrodes orientated circumferentially (86 vs 10%). High-energy pacing accelerated entrainment over the entire mapped field compared to low-energy pacing (3.1±1.5 vs 7.3±2.4 impulses, p < 0.001). Regardless of the location of the pacing site, the new site of slow-wave initiation was always located 4-12 mm away from the pacing site, between the greater curvature and negative pacing electrode. A pacing period between 14-30 s resulted in stable slow-wave initiation and entrainment.

CONCLUSION

These data will now inform effective application of gastric pacing in future studies, including human translation.

Gastrointestinal Motility Disorders Correlate with Intracranial Bleeding, Opioid Use, and Brainstem Edema in Neurosurgical Patients

BACKGROUND

Gastrointestinal (GI) motility disorders may be directly associated with the intensity of acute brain injury, edema of the brainstem, and opioid use in neurosurgical patients.

METHODS

In this retrospective study, patient demographic characteristics, computed tomography (CT) scans, the occurrence of gastroparesis, constipation, and opioid use were registered during the intensive care unit (ICU) stay and correlated with days of mechanical ventilation, length of ICU stay, and survival. Gastroparesis was defined as residual gastric volume > 250 mL per day, and constipation was defined as the absence of stool for 3 days or more during the ICU stay.

RESULTS

Of 207 neurosurgical patients screened, 69 adult patients who spent more than 4 days in the ICU were included in the study. Gastroparesis was observed in 48 (69.6%) patients, constipation was observed in 67 (97.1%) patients, and stress ulcers were observed in 4 (5.8%) patients. Patients with brainstem edema (n = 57, 82.6%) had the first stool evacuation later compared with patients with no edema (8 [interquartile range (IQR) 5.25-9.75] vs. 3.5 [IQR 2.25-4] days; P < 0.001). In the logistic regression analysis, factors that were associated with GI dysmotility were central nervous system (CNS) bleeding (odds ratio [OR] 5.1, 95% confidence interval [CI] 1.26-20.8, P = 0.02), opioid use > 19.3 morphine equivalents (ME) per day (OR 5.37, 95% CI 1.1-27.1, P = 0.04), and brainstem edema (OR 4.9, 95% CI 1.1-21.6, P = 0.04). A receiver operating characteristic curve analysis confirmed that the cutoff value of > 6.78 ME per day was a good predictor determining GI dysmotility, with 89.5% sensitivity and 72.7% specificity (95% CI 0.67-0.88, area under the curve 0.784, Youden index 0.62, P = 0.001). Poor survival correlated with lower Glasgow Coma Score values (ρ =  - 520, P < 0.001), CNS bleeding (ρ = 0.393, P < 0.001), associated cardiac diseases (ρ = 0.279, P < 0.001), and cardiorespiratory arrest on admission (ρ = 0.315, P < 0.001), but not with GI dysmotility (ρ = 0.175, P = 0.402).

CONCLUSIONS

Significant correlation was registered between brainstem edema, gastrointestinal dysmotility, and opioids. CNS bleeding was the most important single factor influencing GI dysmotility. Further studies with opioid and nonopioid sedation may distinguish the influence of acute brain lesions versus drugs on GI dysmotility.

Haustral rhythmic motor patterns of the human large bowel revealed by ultrasound

Effective and widely available strategies are needed to diagnose colonic motility dysfunction. We investigated whether ultrasonography could generate spatiotemporal maps combined with motor pattern frequency analysis, to become a noninvasive method to characterize human colon motor patterns. Abdominal colonic ultrasonography was performed on healthy subjects (N = 7), focusing on the detailed recording of spontaneous haustral activities. We developed image segmentation and frequency analysis software to analyze the motor patterns captured. Ultrasonography recordings of the ascending, transverse, and descending colon identified three distinct rhythmic motor patterns: the 1 cycle/min and the 3 cycles/min cyclic motor pattern were seen throughout the whole colon, whereas the 12 cycles/min cyclic motor pattern was identified in the ascending colon. The rhythmic motor patterns of the human colon that are associated with interstitial cells of Cajal-associated pacemaking activity can be accurately identified and quantified using ultrasound.NEW & NOTEWORTHY Ultrasonography in the clinical field is an underutilized tool for assessing colonic motility; however, with the addition of frequency analysis techniques, it provides a method to identify human colonic motor patterns. Here we report on the 1, 3, and 12 cpm rhythmic motor patterns. Ultrasound has the potential to become a bedside assessment for colonic dysmotility and may reveal the health of interstitial cells of Cajal (ICC) pacemaker activities.

Tryptophan-synthesizing bacteria enhance colonic motility

BACKGROUND

An emerging strategy to treat symptoms of gastrointestinal (GI) dysmotility utilizes the administration of isolated bacteria. However, the underlying mechanisms of action of these bacterial agents are not well established. Here, we elucidate a novel approach to promote intestinal motility by exploiting the biochemical capability of specific bacteria to produce the serotonin (5-HT) precursor, tryptophan (Trp).

METHODS

Mice were treated daily for 1 week by oral gavage of Bacillus (B.) subtilis (R0179), heat-inactivated R0179, or a tryptophan synthase-null strain of B. subtilis (1A2). Tissue levels of Trp, 5-HT, and 5-hydroxyindoleacetic acid (5-HIAA) were measured and changes in motility were evaluated.

KEY RESULTS

Mice treated with B. subtilis R0179 exhibited greater colonic tissue levels of Trp and the 5-HT breakdown product, 5-HIAA, compared to vehicle-treated mice. Furthermore, B. subtilis treatment accelerated colonic motility in both healthy mice as well as in a mouse model of constipation. These effects were not observed with heat-inactivated R0179 or the live 1A2 strain that does not express tryptophan synthase. Lastly, we found that the prokinetic effects of B. subtilis R0179 were blocked by coadministration of a 5-HT4 receptor (5-HT4 R) antagonist and were absent in 5-HT4 R knockout mice.

CONCLUSIONS AND INFERENCES

Taken together, these data demonstrate that intestinal motility can be augmented by treatment with bacteria that synthesize Trp, possibly through increased 5-HT signaling and/or actions of Trp metabolites, and involvement of the 5-HT4 R. Our findings provide mechanistic insight into a transient and predictable bacterial strategy to promote GI motility.

Effect of cholecystokinin on small intestinal motility in suncus murinus

In a fasting gastrointestinal tract, a characteristic cyclical rhythmic migrating motor complex (MMC) occur that comprises of three phases: I, II, and III. Among these, phase III contractions propagate from the stomach to the lower intestine in mammals, including humans, dogs, and Suncus murinus (suncus). Apart from the phase III of MMC propagating from the stomach, during the gastric phase II, small intestine-originated strong contractions propagate to the lower small intestine; however, the mechanism of contractions originating in the small intestine has not been clarified. In this study, we aimed to elucidate the role of cholecystokinin (CCK) in small intestinal motility. Administration of sulfated CCK-8 in phase I induced phase II-like contractions in the small intestine, which lasted for approximately 10-20 min and then returned to the baseline, while no change was observed in the stomach. Contractions of small intestine induced by CCK-8 were abolished by lorglumide, a CCK1 receptor antagonist. Gastrin, a ligand for the CCK2 receptor, evoked strong contractions in the stomach, but did not induce contractions in the small intestine. To examine the effect of endogenous CCK on contractions of small intestinal origin, lorglumide was administered during phase II. However, there was no change in the duodenal motility pattern, and strong contractions of small intestinal origin were not abolished by treatment with lorglumide. These results suggest that exogenous CCK stimulates contractions of small intestine via CCK1 receptors, whereas endogenous CCK is not involved in the strong contractions of small intestinal origin.

Pyridostigmine in chronic intestinal pseudo-obstruction - a systematic review

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) may be a primary or secondary phenomenon and is often multifactorial. Treatment is largely directed at improving colonic motility. The use of cholinesterase inhibitors such as pyridostigmine has been hypothesized to increase acetylcholine in the bowel, improving symptoms and transit times.

METHODS

A systematic review of the use of pyridostigmine in CIPO was conducted using scientific and commercial search engines identifying scientific studies enrolling adult human subjects, published from 2000 to 2022 in the English language.

RESULTS

Four studies were identified including two randomized controlled trials (RCT) and two observational studies. The studies had heterogenous inclusion criteria, dosing regimens and reported outcomes. Two studies were identified as being at high risk of bias. All studies reported improved patient outcomes with use of pyridostigmine, and low rates (4.3%) of mild cholinergic side effects. No major side effects were reported.

CONCLUSION

The use of pyridostigmine in management of CIPO is biologically plausible due to its ability to increase colonic motility, and early studies on its role are uniformly suggestive of benefit with low side-effect profile. Four clinical studies have been conducted to date, with small sample sizes, heterogeneity and high risk of bias. Further high-quality studies are required to enable assessment of pyridostigmine's utility as an effective management strategy in CIPO.

Ultrasonographic Assessment of Small Intestinal Motility Following Hyoscine Butylbromide Administration in Horses: A Pilot Study

Horses commonly receive hyoscine butylbromide (HB) prior to hospital admission for colic. This could alter the appearance of the small intestine (SI) on ultrasound scan and affect clinical decision making. The aim of this study was to assess the impact of HB on ultrasonographically assessed SI motility and heart rate. Six horses hospitalised for medical colic with no significant abnormalities on baseline abdominal ultrasound examination were included. Ultrasound was performed in three locations (right inguinal, left inguinal and hepatoduodenal window) before and at 1, 5, 15, 30, 45, 60, 90, and 120 minutes after intravenous injection of 0.3 mg/kg HB. Three blinded reviewers assessed SI motility using a subjective grading scale from 1 to 4, one being normal motility and four being no motility. Moderate interindividual and interobserver variability was observed, but none of the included horses developed dilated turgid loops of SI. Hyoscine butylbromide did not significantly reduce SI motility grade in any location (P = .60 left inguinal, P = .16 right inguinal, P = .09 duodenum). Heart rate (mean ± SD) was 33 ± 3 prior to HB injection and peaked at 71.3 ± 9 one-minute postinjection. Heart rate was significantly increased until 45 minutes (48 ± 9) after HB administration (P = .04). The appearance of dilated turgid SI loops common with strangulating intestinal lesions did not appear to develop following HB administration. Hyoscine butylbromide administered shortly before abdominal ultrasound examination would not be expected to affect clinical decision making in horses without small intestinal disease.

Ramadan intermittent fasting reduces visceral fat and improves gastrointestinal motility

BACKGROUND

Ramadan is a model of intermittent fasting linked with possible beneficial effects. Scarce information, however, is available about the combined effects of Ramadan intermittent fasting (RIF) on anthropometric and metabolic indices, gastrointestinal symptoms, and motility.

METHODS

In 21 healthy Muslims, we assessed the impact of RIF on caloric intake, physical activity, gastrointestinal symptoms and motility (gastric/gallbladder emptying by ultrasonography, orocaecal transit time by lactulose breath test), anthropometric indices, subcutaneous and visceral fat thickness (ultrasonography), glucose and lipid homeostasis.

RESULTS

Mean caloric intake decreased from a median of 2069 kcal (range 1677-2641) before Ramadan to 1798 kcal (1289-3126) during Ramadan and increased again to 2000 kcal (1309-3485) after Ramadan. Although physical activity remained stable before, during, and after RIF, body weight, body mass index and waist circumference decreased in all subjects and in both genders, together with a significant decrease in subcutaneous and visceral fat thickness and insulin resistance. The postprandial gastric emptying speed was significantly faster after than before RIF. Fasting gallbladder volume was about 6% smaller after, than before Ramadan, with a stronger and faster postprandial gallbladder contraction. After RIF, lactulose breath test documented increased microbiota carbohydrate fermentation (postprandial H2 peak), and faster orocaecal transit time. RIF also significantly improved gastric fullness, epigastric pain and heartburn.

CONCLUSIONS

RIF generates, in healthy subjects, multiple systemic beneficial effects in terms of fat burden, metabolic profile, gastrointestinal motility and symptoms. Further comprehensive studies should assess the potential beneficial effects of RIF in diseased people.

Effects of the gaseous signalling molecule nitroxyl (HNO) on myenteric neurons governing intestinal motility

OBJECTIVES

The main function of myenteric neurons is the control of gut motility. As we recently showed that nitroxyl (HNO) induces intestinal smooth muscle relaxation, it was of interest to evaluate the effects of this signalling molecule on myenteric neurons in order to distinguish its properties in regard to myocytes.

METHODS

Myenteric neurons isolated from the ileum of 4-10 days old rats were used. HNO-induced changes in intracellular concentration of Ca2+ or membrane potential and ion currents were measured using the Ca2+-sensitive fluorescent dye fura-2 AM or by electrophysiological whole-cell recordings, respectively. Changes in intracellular thiol groups pool were evaluated using thiol tracker violet. Angeli's salt was used as HNO donor.

RESULTS

The HNO donor Angeli's salt induced a significant increase in the cytosolic Ca2+ concentration at the concentration 50 µM and a membrane hyperpolarization from a resting membrane potential of -56.1 ± 8.0 mV to -63.1 ± 8.7 mV (n=7). Although potassium channels primarily drive membrane potential changes in these cells, outwardly rectifying potassium currents were not significantly affected by 50 µM Angeli's salt. Fast inward sodium currents were slightly but not significantly reduced by HNO. In more sensitive cells, HNO tended to reduce the pool of thiol groups.

CONCLUSIONS

As in the case of smooth muscle cells, HNO causes hyperpolarization of myenteric neurons, an effect also associated with an increase in intracellular Ca2+ concentration. Pathways other than activation of potassium currents appear to drive the hyperpolarization evoked by HNO.

Mini-review: Enteric glial cell reactions to inflammation and potential therapeutic implications for GI diseases, motility disorders, and abdominal pain

Enteric glial cells are emerging as critical players in the regulation of intestinal motility, secretion, epithelial barrier function, and gut homeostasis in health and disease. Enteric glia react to intestinal inflammation by converting to a 'reactive glial phenotype' and enteric gliosis, contributing to neuroinflammation, enteric neuropathy, bowel motor dysfunction and dysmotility, diarrhea or constipation, 'leaky gut', and visceral pain. The focus of the minireview is on the impact of inflammation on enteric glia reactivity in response to diverse insults such as intestinal surgery, ischemia, infections (C. difficile infection, HIV-Tat-induced diarrhea, endotoxemia and paralytic ileus), GI diseases (inflammatory bowel diseases, diverticular disease, necrotizing enterocolitis, colorectal cancer) and functional GI disorders (postoperative ileus, chronic intestinal pseudo-obstruction, constipation, irritable bowel syndrome). Significant progress has been made in recent years on molecular pathogenic mechanisms of glial reactivity and enteric gliosis, resulting in enteric neuropathy, disruption of motility, diarrhea, visceral hypersensitivity and abdominal pain. There is a growing number of glial molecular targets with therapeutic implications that includes receptors for interleukin-1 (IL-1R), purines (P2X2R, A2BR), PPARα, lysophosphatidic acid (LPAR1), Toll-like receptor 4 (TLR4R), estrogen-β receptor (ERβ) adrenergic α-2 (α-2R) and endothelin B (ETBR), connexin-43 / Colony-stimulating factor 1 signaling (Cx43/CSF1) and the S100β/RAGE signaling pathway. These exciting new developments are the subject of the minireview. Some of the findings in pre-clinical models may be translatable to humans, raising the possibility of designing future clinical trials to test therapeutic application(s). Overall, research on enteric glia has resulted in significant advances in our understanding of GI pathophysiology.

Gum Chewing and Coffee Consumption but not Caffeine Intake Improve Bowel Function after Gastrointestinal Surgery: a Systematic Review and Network Meta-analysis

BACKGROUND

Postoperative ileus is common after gastrointestinal surgery. This network meta-analysis aimed to compare the effectiveness of gum chewing and coffee and caffeine intake on ileus-related outcomes.

METHODS

A systematic literature review was performed to identify randomized controlled trials (RCTs) comparing noninvasive treatments for ileus after gastrointestinal surgery. The main analyses included random effects network meta-analyses using frequentist methods with simultaneous direct and indirect comparisons of time to first flatus, time to first defecation, and length of stay. Bayesian network meta-analysis using Markov chains was also used.

RESULTS

A total of 32 RCTs comparing 4999 patients were included in this network meta-analysis. Time to flatus was reduced by gum chewing (mean difference compared to control (MD): -11 h, 95% confidence interval (95% CI) - 16 to - 5 h, P < 0.001). Time to defecation was reduced by gum chewing and coffee, with MDs of -18 h (95% CI - 23 to - 13 h, P < 0.001) and -13 h (95% CI - 24 to - 1 h, P < 0.001), respectively. Length of stay was reduced by coffee and gum chewing with MDs of - 1.5 days (95% CI: - 2.5 to - 0.6 days, P < 0.001) and - 0.9 days (95% CI: - 1.3 to - 0.4 days, P < 0.001), respectively.

CONCLUSION

Coffee and gum chewing were proven to be effective noninvasive approaches for shortening the postoperative length of hospital stay and time to first defecation, especially in open gastrointestinal surgery; thus these actions should be recommended after gastrointestinal surgery.

Pan-alimentary assessment of motility, luminal content, and structures: an MRI-based framework

BACKGROUND

Gastrointestinal symptoms originating from different segments overlap and complicate diagnosis and treatment. In this study, we aimed to develop and test a pan-alimentary framework for the evaluation of gastrointestinal (GI) motility and different static endpoints based on magnetic resonance imaging (MRI) without contrast agents or bowel preparation.

METHODS

Twenty healthy volunteers (55.6 ± 10.9 years, BMI 30.8 ± 9.2 kg/m2) underwent baseline and post-meal MRI scans at multiple time points. From the scans, the following were obtained: Gastric segmental volumes and motility, emptying half time (T50), small bowel volume and motility, colonic segmental volumes, and fecal water content. Questionnaires to assess GI symptoms were collected between and after MRI scans.

KEY RESULTS

We observed an increase in stomach and small bowel volume immediately after meal intake from baseline values (p<.001 for the stomach and p=.05 for the small bowel). The volume increase of the stomach primarily involved the fundus (p<.001) in the earliest phase of digestion with a T50 of 92.1 ± 35.3 min. The intake of the meal immediately elicited a motility increase in the small bowel (p<.001). No differences in colonic fecal water content between baseline and 105 min were observed.

CONCLUSION & INFERENCES

We developed a framework for a pan-alimentary assessment of GI endpoints and observed how different dynamic and static physiological endpoints responded to meal intake. All endpoints aligned with the current literature for individual gut segments, showing that a comprehensive model may unravel complex and incoherent gastrointestinal symptoms in patients.

Perinatal high-fat diet exposure alters oxytocin and corticotropin releasing factor inputs onto vagal neurocircuits controlling gastric motility

Perinatal high-fat diet (pHFD) exposure alters the development of vagal neurocircuits that control gastrointestinal (GI) motility and reduce stress resiliency in offspring. Descending oxytocin (OXT; prototypical anti-stress peptide) and corticotropin releasing factor (CRF; prototypical stress peptide) inputs from the paraventricular nucleus (PVN) of the hypothalamus to the dorsal motor nucleus of the vagus (DMV) modulate the GI stress response. How these descending inputs, and their associated changes to GI motility and stress responses, are altered following pHFD exposure are, however, unknown. The present study used retrograde neuronal tracing experiments, cerebrospinal fluid extraction, in vivo recordings of gastric tone, motility and gastric emptying rates, and in vitro electrophysiological recordings from brainstem slice preparations to investigate the hypothesis that pHFD alters descending PVN-DMV inputs and dysregulates vagal brain-gut responses to stress. Compared to controls, rats exposed to pHFD had slower gastric emptying rates and did not respond to acute stress with the expected delay in gastric emptying. Neuronal tracing experiments demonstrated that pHFD reduced the number of PVNOXT neurons that project to the DMV, but increased PVNCRF neurons. Both in vitro electrophysiology recordings of DMV neurons and in vivo recordings of gastric motility and tone demonstrated that, following pHFD, PVNCRF -DMV projections were tonically active, and that pharmacological antagonism of brainstem CRF1 receptors restored the appropriate gastric response to brainstem OXT application. These results suggest that pHFD exposure disrupts descending PVN-DMV inputs, leading to a dysregulated vagal brain-gut response to stress. KEY POINTS: Maternal high-fat diet exposure is associated with gastric dysregulation and stress sensitivity in offspring. The present study demonstrates that perinatal high-fat diet exposure downregulates hypothalamic-vagal oxytocin (OXT) inputs but upregulates hypothalamic-vagal corticotropin releasing factor (CRF) inputs. Both in vitro and in vivo studies demonstrated that, following perinatal high-fat diet, CRF receptors were tonically active at NTS-DMV synapses, and that pharmacological antagonism of these receptors restored the appropriate gastric response to OXT. The current study suggests that perinatal high-fat diet exposure disrupts descending PVN-DMV inputs, leading to a dysregulated vagal brain-gut response to stress.