Gastrointestinal hormones and regulation of gastric emptying

Managing gastrointestinal manifestations in systemic sclerosis, a mechanistic approach

INTRODUCTION

Systemic sclerosis (SSc) is a connective tissue disease with heterogeneous presentation. Gastrointestinal (GI) complications of SSc are characterized by esophageal reflux, abnormal motility, and microbiome dysbiosis, which impact patient quality of life and mortality. Preventative therapeutics are lacking, with management primarily aimed at symptomatic control.

AREAS COVERED

A broad literature review was conducted through electronic databases and references from key articles. We summarize the physiology of gastric acid production and GI motility to provide context for existing therapies, detail the current understanding of SSc-GI disease, and review GI medications studied in SSc. Finally, we explore new therapeutic options. We propose a management strategy that integrates data on drug efficacy with knowledge of disease pathophysiology, aiming to optimize future therapeutic targets.

EXPERT OPINION

SSc-GI complications remain a challenge for patients, clinicians, and investigators alike. Management presently focuses on treating symptoms and minimizing mucosal damage. Little evidence exists to suggest immunosuppressive therapy halts progression of GI involvement or reverses damage, leaving many unanswered questions about the optimal clinical approach. Further research focused on identifying patients at risk for GI progression, and the underlying mechanism(s) that drive disease will provide opportunities to prevent long-term damage, and significantly improve patient quality of life.

Moringa oleifera Lam. Leaf improves constipation of rats induced by low-fiber-diet: A proteomics study

ETHNOPHARMACOLOGICAL RELEVANCE

The leaf of Moringa oleifera Lam., a medicinal and edible herb for thousands of years in Ayurveda, is used as Pancha (na) karma (purgative) during and after the body cleansing process, to treat constipation, reduce cholesterol and body weight.

AIM OF STUDY

The aim was to investigate the diarrhea effects and possible mechanism of M. oleifera leaves in constipation rats.

MATERIALS AND METHODS

The hot water extract of M. oleifera leaves (WEMOL) was prepared and analyzed using LC-20AT HPLC system. The constipated rat model was induced by feeding with low fiber diet for 21 days. After oral administration of WEMOL for 7 days, the excretion parameter analysis, gastro-intestinal propulsion, histological analysis by HE and Alcian blue staining, and gastrointestinal hormone in rat's digestive tract through ELISA were used to evaluate the laxative effect of WEMOL. Label-free quantitation (LFQ) with LC-MS/MS, bioinformatics and Western blot were used to discover and verify the signal pathways and key proteins of WEMOL related to diarrhea.

RESULTS

The contents of isoquercitrin and astragalin were 2.7 mg/g and 1.7 mg/g, respectively in WEMOL. The stool number, weight, and water content of constipation rats were significantly reduced, indicating model had been established successfully. WEMOL (1.25 and 2.5 g/kg) increased water content of feces and the levels of Gas, MTL, NPY in gastric antrum and VIP, SP in colon of constipation rats, improved the muscle layer thickness and mucin secretion of colon. The proteomics revealed a total of 1731 differential proteins and 9 signaling pathways, WEMOL increased the expression of Vamp2, Gnai3, and Prkacb.

CONCLUSIONS

The laxative mechanism of WEMOL maybe modulate the signaling pathways mediated by 5-HT and Ach receptors, related to gastrointestinal motility and intestinal fluid secretion. It can be considered as the scientific connotation of Pancha (na) karma of M. oleifera leaves in ayurveda.

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.

Synergistic Strategies for Gastrointestinal Cancer Care: Unveiling the Benefits of Immunonutrition and Microbiota Modulation

Gastrointestinal (GI) cancers are a group of highly prevalent malignant tumors affecting the gastrointestinal tract. Globally, one in four cancer cases and one in three cancer deaths are estimated to be GI cancers. They can alter digestive and absorption functions, leading to severe malnutrition which may worsen the prognosis of the patients. Therefore, nutritional intervention and monitoring play a fundamental role in managing metabolic alterations and cancer symptoms, as well as minimizing side effects and increasing the effectiveness of chemotherapy. In this scenario, the use of immunonutrients that are able to modulate the immune system and the modification/regulation of the gut microbiota composition have gained attention as a possible strategy to improve the conditions of these patients. The complex interaction between nutrients and microbiota might contribute to maintaining the homeostasis of each individual's immune system; therefore, concurrent use of specific nutrients in combination with traditional cancer treatments may synergistically improve the overall care of GI cancer patients. This work aims to review and discuss the role of immunonutrition and microbiota modulation in improving nutritional status, postoperative recovery, and response to therapies in patients with GI cancer.

Gut-to-brain spreading of pathology in synucleinopathies: A focus on molecular signalling mediators

Synucleinopathies are a group of neurodegenerative disorders, classically characterized by the accumulation of aggregated alpha synuclein (aSyn) in the central nervous system. Parkinson's disease (PD) and multiple system atrophy (MSA) are the two prominent members of this family. Current treatment options mainly focus on the motor symptoms of these diseases. However, non-motor symptoms, including gastrointestinal (GI) symptoms, have recently gained particular attention, as they are frequently associated with synucleinopathies and often arise before motor symptoms. The gut-origin hypothesis has been proposed based on evidence of an ascending spreading pattern of aggregated aSyn from the gut to the brain, as well as the comorbidity of inflammatory bowel disease and synucleinopathies. Recent advances have shed light on the mechanisms underlying the progression of synucleinopathies along the gut-brain axis. Given the rapidly expanding pace of research in the field, this review presents a summary of the latest findings on the gut-to-brain spreading of pathology and potential pathology-reinforcing mediators in synucleinopathies. Here, we focus on 1) gut-to-brain communication pathways, including neuronal pathways and blood circulation, and 2) potential molecular signalling mediators, including bacterial amyloid proteins, microbiota dysbiosis-induced alterations in gut metabolites, as well as host-derived effectors, including gut-derived peptides and hormones. We highlight the clinical relevance and implications of these molecular mediators and their possible mechanisms in synucleinopathies. Moreover, we discuss their potential as diagnostic markers in distinguishing the subtypes of synucleinopathies and other neurodegenerative diseases, as well as for developing novel individualized therapeutic options for synucleinopathies.

Arctiin alleviates functional constipation by enhancing intestinal motility in mice

Functional constipation (FC), a common symptom that is primarily associated with intestinal motility dysfunction, is a common problem worldwide. Arctiin (Arc) is a lignan glycoside isolated from the Chinese herbal medicine Arctium lappa L., which is a health food in China. The present study aimed to evaluate the laxative effects of Arc against FC in mice. A model of FC induced by loperamide (5 mg/kg) was established in male Institute of Cancer Research (ICR) mice. Arc was administered at a dose of 100 mg/kg as a protective agent. The faecal status, intestinal motility and histological analyses were evaluated. Furthermore, the levels of gastrointestinal motility-associated neurotransmitters, such as motilin (MTL), nitric oxide (NO), and brain-derived neurotrophic factor (BDNF) and the protective effect of Arc on interstitial cells of Cajal (ICC) were assessed. Arc treatment reversed the loperamide-induced reduction in faecal number and water content and the intestinal transit ratio in ICR mice. Histological analysis confirmed that Arc administration mitigated colonic injury. Moreover, Arc treatment increased levels of motilin and brain-derived neurotrophic factor while decreasing nitric oxide levels and ICC injury in the colon of FC mice. Arc decreased inflammation induction and aquaporin expression levels. Owing to its pro-intestinal motility property, Arc was shown to have a protective effect against FC and may thus serve as a promising therapeutic strategy for the management of FC.

Effect of sleeve gastrectomy and Roux-en-Y gastric bypass on gastrointestinal physiology

BACKGROUND

Knowledge regarding the gastrointestinal physiology after sleeve gastrectomy and Roux-en-Y gastric bypass is urgently needed to understand, prevent and treat the nutritional and pharmacological complications of bariatric surgery.

AIM

To investigate the effect of sleeve gastrectomy and Roux-en-Y gastric bypass on gastrointestinal motility (e.g., transit and pressure), pH, and intestinal bile acid concentration.

MATERIAL AND METHODS

An exploratory cross-sectional study was performed in six participants living with obesity, six participants who underwent sleeve gastrectomy, and six participants who underwent Roux-en-Y gastric bypass. During the first visit, a wireless motility capsule (SmartPill©) was ingested after an overnight fast to measure gastrointestinal transit, pH, and pressure. During the second visit, a gastric emptying scintigraphy test of a nutritional drink labeled with ^99mTc-colloid by a dual-head SPECT gamma camera was performed to measure gastric emptying half-time (GET_1/2). During the third visit, two customized multiple lumen aspiration catheters were positioned to collect fasting and postprandial intestinal fluids to measure bile acid concentration.

RESULTS

Immediate pouch emptying (P = 0.0007) and a trend for faster GET_1/2 (P = 0.09) were observed in both bariatric groups. There was a tendency for a shorter orocecal transit in participants with sleeve gastrectomy and Roux-en-Y gastric bypass (P = 0.08). The orocecal segment was characterized by a higher 25th percentile pH (P = 0.004) and a trend for a higher median pH in both bariatric groups (P = 0.07). Fasting total bile acid concentration was 7.5-fold higher in the common limb after Roux-en-Y gastric bypass (P < 0.0001) and 3.5-fold higher in the jejunum after sleeve gastrectomy (P = 0.009) compared to obesity. Postprandial bile acid concentration was 3-fold higher in the jejunum after sleeve gastrectomy (P = 0.0004) and 6.5-fold higher in the common limb after Roux-en-Y gastric bypass (P < 0.0001) compared to obesity.

CONCLUSION

The anatomical alterations of sleeve gastrectomy and Roux-en-Y gastric bypass have an important impact on gastrointestinal physiology. This data confirms changes in transit and pH and provides the first evidence for altered intraluminal bile acid concentration.

Gastric sensorimotor function and its clinical measurement

BACKGROUND

Gastroduodenal symptoms are highly prevalent, with underlying sensorimotor dysfunction contributing in many patients. Common symptoms include early satiation, postprandial fullness, epigastric bloating, pain or burning, nausea and vomiting, which collectively affect over 7% of adults. However, the clinical evaluation of these symptoms remains challenging, with current tests of gastric function remaining limited in their ability or availability to separate specific patient subgroups or guide-targeted care.

PURPOSE

In the current edition of Neurogastroenterology & Motility, Silver et al. present new data showing correlations between patterns of intragastric meal distribution and symptom profiles in a large series of patients undergoing gastric emptying scintigraphy. Studies of this type are important, as they motivate understanding beyond existing disease labels, and orient focus toward deeper mechanistic profiling. This brief review provides an overview of gastric sensorimotor function and profiles several current and emerging methods of clinical evaluation. Perspectives are provided on accommodation testing, gastric emptying, measuring gastric myoelectrical activity including new approaches, and antroduodenal manometry. Although gastric physiology is complex, recent progress has been encouraging, with the heterogenous pathophysiology of gastric symptoms continuing to be unraveled, and new techniques for evaluating gastric function and symptoms emerging.

CONCLUSIONS AND INFERENCES

Ongoing progress will now depend on continuing to accurately profile the underlying mechanisms of gastroduodenal disorders to identify specific disease phenotypes that inform care.

Investigation of the improving effect of raw and charred hawthorn on functional dyspepsia based on interstitial cells of Cajal

Background

Raw hawthorn (RH) is a traditional Chinese medicine commonly used to treat indigestion. Charred hawthorn (CH) is obtained from RH by charring. It is reported that the effect of CH treatment on dyspepsia is stronger than RH. However, this has not been fully proven. The purpose of this study was to compare the effects of RH and CH on functional dyspepsia (FD) model rats. And contribute to the development of dietary therapy for dyspepsia.

Methods

SPF-grade male SD rats were divided into 5 groups: the control group, the model group, the Mos group, the RH group, and the CH group. The FD rat model was established by using the methods of water restriction, fasting, tilting cage restraint, day and night upside down, swimming, and tail damping. The body weight of rats in each group was recorded. And the gastric emptying rate, intestinal propulsive rate, and the levels of motilin (MTL), gastrin (GAS), and 5-HT in serum were compared in each group. The expression of C-kit in the stomach and small intestine of each group was compared by immunofluorescence and PCR.

Results

RH and CH could increase weight, improve the gastric emptying rate and intestinal propulsive rate, and promote the secretion of motilin (MTL), gastrin (GAS), and 5-HT in the serum of FD rats. RH and CH can upregulate the expression of the characteristic protein c-kit of ICC in the stomach and small intestine of FD model rats, and the effect of CH is stronger than RH.

Conclusion

RH and CH may increase the number of interstitial cells of Cajal (ICC) in the gastrointestinal tract by upregulating c-kit expression, thus improving gastrointestinal motility in FD model rats. And compared with RH, CH has certain advantages.