Colonic movements in healthy subjects as monitored by a Magnet Tracking System

Whole Gut Motility Patterns in Patients with Chronic Nausea and Vomiting

Background/Objectives: Chronic nausea and vomiting (N/V) disorders are common in clinical practice. Our primary aim was to compare total and segmental gastrointestinal transit times as well as gastric contraction patterns in patients with chronic N/V syndrome to those of healthy volunteers (HVs). In the patient group, our secondary aim was to explore how symptoms and motility patterns were affected by a serotonin HT4 receptor agonist (Prucalopride). Methods: Patients with chronic N/V syndrome and HVs underwent baseline assessment of regional gastrointestinal (GI) motility/transit using the Motilis 3D-Transit system. Patients were then treated with Prucalopride 2 mg daily for 28 days, with the 3D-transit examination repeated within 10-20 days after treatment onset. Two self-administered questionnaires (the Gastrointestinal Symptom Rating Scale [GSRS] and Gastroparesis Cardinal Symptom Index [GCSI]) were used to assess patients' symptoms. Results: A total of 19 patients (13 F; median age 25 years (IQR 22-39) and 55 HVs (25 F; median age 28 (24-35) were included. At baseline, no differences in regional GI transit times were found between groups. However, patients had a significantly lower gastric contraction amplitude than HVs (9 mmHg (IQR 8-11) vs. 12 (10-15: p < 0.001). In response to Prucalopride treatment, gastric emptying time was reduced from a median of 3.1 h to 1.6 h (p < 0.005). Further, the GCSI was significantly reduced from GCSI 3.0 (IQR 2.3-3.7) at baseline to GCSI 1.9 (IQR 1.3-3.2) with Prucalopride. Conclusions: Patients with chronic N/V syndrome have significantly lower gastric contraction amplitude than HVs and may symptomatically benefit from prokinetics. They do not, however, have evidence of panenteric dysmotility.

Review article: Current status and future directions of ingestible electronic devices in gastroenterology

BACKGROUND

Advances in microelectronics have greatly expanded the capabilities and clinical potential of ingestible electronic devices.

AIM

To provide an overview of the structure and potential impact of ingestible devices in development that are relevant to the gastrointestinal tract.

METHODS

We performed a detailed literature search to inform this narrative review.

RESULTS

Technical success of ingestible electronic devices relies on the ability to miniaturise the microelectronic circuits, sensors and components for interventional functions while being sufficiently powered to fulfil the intended function. These devices offer the advantages of being convenient and minimally invasive, with real-time assessment often possible and with minimal interference to normal physiology. Safety has not been a limitation, but defining and controlling device location in the gastrointestinal tract remains challenging. The success of capsule endoscopy has buoyed enthusiasm for the concepts, but few ingestible devices have reached clinical practice to date, partly due to the novelty of the information they provide and also due to the challenges of adding this novel technology to established clinical paradigms. Nonetheless, with ongoing technological advancement and as understanding of their potential impact emerges, acceptance of such technology will grow. These devices have the capacity to provide unique insight into gastrointestinal physiology and pathophysiology. Interventional functions, such as sampling of tissue or luminal contents and delivery of therapies, may further enhance their ability to sharpen gastroenterological diagnoses, monitoring and treatment.

CONCLUSIONS

The development of miniaturised ingestible microelectronic-based devices offers exciting prospects for enhancing gastroenterological research and the delivery of personalised, point-of-care medicine.

A novel perspective on constipation secondary to sigmoidocele: a retrospective study

PURPOSE

Sigmoidocele, which is a type of obstructed defecation syndrome (ODS), is a peritoneal hernia of the pelvic floor that has been seldom studied individually. This study investigated the anatomic characteristics of sigmoidocele based on imaging features.

METHODS

This retrospective cohort population comprised adult patients with ODS who underwent defecography between December 2017 and July 2020. Sigmoidocele was classified based on existing criteria. Novel radiological parameters including the vertical distance descended by the sigmoid colon from rest to maximum straining (RMS) and from the inferior border of the sigmoid colon to the superior border of the rectum at maximum straining (MSR) were measured.

RESULTS

Among 275 patients with sigmoidocele, 251 (91.6%) were female. The mean age was 51.53±12.99 years. We classified 26, 205, and 44 cases as grades I, II, and III, respectively. Patients with more severe sigmoidocele had greater sigmoid colon mobility (RMS: 19.13±8.54 mm, 34.45±14.51 mm, and 48.70±20.05 mm for grades I, II, and III, respectively; p < 0.001) and more pronounced compression of the rectum by the sigmoid colon at maximum straining (MSR: 35.23±8.44 mm, 26.33±13.29 mm, and 15.18±18.00 mm, respectively; p < 0.001). We regrouped the patients based on sigmoid colon alignment. Type L patients had the most severe constipation.

CONCLUSION

Our study presents a novel sigmoidocele classification. The anatomic appearance and location of the herniated sigmoid colon observed using fluoroscopy during defecation may help improve the clinical awareness of ODS caused by sigmoidocele.

Prediction of death probability in adenocarcinoma of the transverse colon: competing-risk nomograms based on 21,469 patients

PURPOSE

Tumors in parts of the colon other than the transverse colon have been well studied, but little is known about adenocarcinoma of the transverse colon (ATC).The aim of this study was to construct nomograms using competing-risk model for accurately predicting the probability of cancer-specific and non-cancer-specific death in patients with ATC.

METHODS

Data on eligible patients recorded during 2000-2019 in the Surveillance, Epidemiology, and End Results database were extracted and screened. Factors that influencing prognosis were screened for death from ATC (DATC) and death from other causes (DOC) using competing-risk analysis, including univariate and multivariate analyses based on Gray's test and the Fine-Gray model, respectively. Independent prognostic factors were identified and nomograms were constructed. For comparison, we also constructed a Cox model and an AJCC stage-only competing-risk model (AJCC model) for patients with DATC. Performance evaluations of the nomograms and comparison between the models were performed using calibration plots, Harrell's concordance index (C-index), receiver operating characteristic (ROC) curves, and the areas under the ROC curve (AUCs). The nomograms and models were validated using a validation cohort. The net reclassification index, integrated discrimination improvement, decision curves, and risk stratification were not assessed because no accepted methods were suited for competing-risk model.

RESULTS

This study included 21,469 patients with ATC, and 17 and 9 independent influencing factors were identified for the construction of DATC nomograms (DATCN) and DOC nomograms (DOCN), respectively. In both the training and validation cohorts, the calibration curves indicated good agreement between the nomogram-based predictions and the actual observations in the two nomograms, respectively. The C-index of the DATCN was higher than 80% (80.3-83.3%) at 1, 3 and 5 years in both the training and validation cohorts, significantly outperforming the AJCC (76.7-78%) and Cox (75.4-79.5%) model. The C-index of the DOCN was also higher than 69% (69.0-73.6%). In terms of ROC curves at each time point, those of the DATCN were very close to the upper-left corner of the coordinate axis in both the training and validation cohorts, and their AUCs were larger than 84% (84.2-85.4%).The AUCs of the AJCC (78.4-81.1%) and Cox (79.4-81.5%) models were significantly lower (p < 0.05), and the curves were closer to the diagonal. The ROC curves of the DOCN was similar to those of the DATCN, and the AUCs were 68.5-74%. The DATCN and DOCN therefore had good consistency, accuracy, and stability, respectively.

CONCLUSION

This study was the first to construct competing-risk nomograms for ATC. These nomograms have proved useful for accurately assessing patient prognoses and allowing more-individualized follow-up strategies, thereby reducing the mortality.

Gastrointestinal Transit Times in Health as Determined Using Ingestible Capsule Systems: A Systematic Review

BACKGROUND

Ingestible capsule (IC) systems can assess gastrointestinal (GI) transit times as a surrogate for gut motility for extended periods of time within a minimally invasive, radiation-free and ambulatory setting.

METHODS

A literature review of IC systems and a systematic review of studies utilizing IC systems to measure GI transit times in healthy volunteers was performed. Screening for eligible studies, data extraction and bias assessments was performed by two reviewers. A narrative synthesis of the results was performed.

RESULTS

The literature review identified 23 different IC systems. The systematic review found 6892 records, of which 22 studies were eligible. GI transit time data were available from a total of 1885 healthy volunteers. Overall, seventeen included studies reported gastric emptying time (GET) and small intestinal transit time (SITT). Colonic transit time (CTT) was reported in nine studies and whole gut transit time (WGTT) was reported in eleven studies. GI transit times in the included studies ranged between 0.4 and 15.3 h for GET, 3.3-7 h for SITT, 15.9-28.9 h for CTT and 23.0-37.4 h for WGTT. GI transit times, notably GET, were influenced by the study protocol.

CONCLUSIONS

This review provides an up-to-date overview of IC systems and reference ranges for GI transit times. It also highlights the need to standardise protocols to differentiate between normal and pathological function.

Overview of the Enteric Nervous System

Propulsion of contents in the gastrointestinal tract requires coordinated functions of the extrinsic nerves to the gut from the brain and spinal cord, as well as the neuromuscular apparatus within the gut. The latter includes excitatory and inhibitory neurons, pacemaker cells such as the interstitial cells of Cajal and fibroblast-like cells, and smooth muscle cells. Coordination between these extrinsic and enteric neurons results in propulsive functions which include peristaltic reflexes, migrating motor complexes in the small intestine which serve as the housekeeper propelling to the colon the residual content after digestion, and mass movements in the colon which lead to defecation.

Role of segmental contraction in the small intestinal digestion: A computational approach to study the physics behind the luminal mixing and transport

Segmentation is well known to digest the food rich in proteins, starch, and lipids; however, the mechanism leading to the digestion remains unclear. In this study, a theoretical model for segmental contractions of the small intestine is developed using lubrication method to explore the mechanisms involved. Here, the nonlinear partial differential equations governing the fluid flow were normalized in viscous regime and solved semi-analytically for a power law fluid under long wavelength approximation on a Matlab^TM platform. Study indicates that shearing is highest at the 1st and 4th mid-occlusion in comparison to 2nd and 3rd mid-occlusion. Parametric study indicates that the flow is sensitive to - the span of segmentation or wavelength of the wave, occlusion of the wave and frequency of the contraction; with shearing being highest for dilatants. Shearing is more prominent at higher occlusion (>50 %) and frequency (>6Hz). Further, mixing is more prominent at the steep regions of the wave; having intensity of mixing highest for the outer waves in comparison to waves at mid-region of the segmentation. The power demand is found to be greater in segmentation and has the following precedence - frequency, wavelength, flow behavior index, and occlusion (up to 80 %). Further, multiplicity of the wave gives rise to multiple zones of mixing which increases the rate of mixing of the contents. Suggesting that, the segmentation primarily serves the purpose of mixing. The study will be useful to explore novel therapeutic strategies of managing patients suffering from various motility-associated disorders of the small intestine.

Faecal incontinence is associated with an impaired rectosigmoid brake and improved by sacral neuromodulation

BACKGROUND

The rectosigmoid brake, characterised by retrograde cyclic motor patterns on high-resolution colonic manometry, has been postulated as a contributor to the maintenance of bowel continence. Sacral neuromodulation (SNM) is an effective therapy for faecal incontinence, but its mechanism of action is unclear. This study aims to investigate the colonic motility patterns in the distal colon of patients with faecal incontinence, and how these are modulated by SNM.

METHODS

A high-resolution fibreoptic colonic manometry catheter, containing 36 sensors spaced at 1-cm intervals, was positioned in patients with faecal incontinence undergoing stage 1 SNM. One hour of pre- and post meal recordings were obtained followed by pre- and post meal recordings with suprasensory SNM. A 700-kcal meal was given. Data were analysed to identify propagating contractions.

RESULTS

Fifteen patients with faecal incontinence were analysed. Patients had an abnormal meal response (fewer retrograde propagating contractions compared to controls; p = 0.027) and failed to show a post meal increase in propagating contractions (mean 17 ± 6/h premeal vs. 22 ± 9/h post meal, p = 0.438). Compared to baseline, SNM significantly increased the number of retrograde propagating contractions in the distal colon (8 ± 3/h premeal vs. 14 ± 3/h premeal with SNM, p = 0.028). Consuming a meal did not further increase the number of propagating contractions beyond the baseline upregulating effect of SNM.

CONCLUSION

The rectosigmoid brake was suppressed in this cohort of patients with faecal incontinence. SNM may exert a therapeutic effect by modulating this rectosigmoid brake.

Direct visualizing of paracetamol immediate release tablet disintegration in vivo and in vitro

The purpose of the present study was to study tablet disintegration by direct visualization, in vivo and in vitro. Based on literature data, a standard conventional paracetamol (CP) tablet, Panodil®, and a rapidly absorbed paracetamol (RP) tablet, Panodil® Zapp, were chosen as model systems to study tablet disintegration in the human stomach. Based on the obtained in vivo results, an in vitro disintegration method was designed to reproduce the visualized disintegration process occurring in the human stomach. For the clinical study, CP and RP tablets fastened to digital endoscopic camera capsules were administered to fasted human volunteers (n=4). The disintegration time and process were visualized by the real time video recordings, using the endoscopic camera capsule. The average disintegration time was found to be 26 ± 13 min and 10 ± 7 min, for CP (n=4) and RP (n=4) tablets, respectively. It was possible to reproduce the in vivo disintegration data in vitro using a USP 2 dissolution apparatus with 250 mL of viscous Fasted State Simulated Gastric Fluid (vFaSSGF*), simulating the rheological profile of human fasted state gastric fluid following administration of a glass of water. The viscosity of the simulated fasted state gastric fluid was found to have a large impact on the disintegration time of the tested immediate release tablets. Therefore, it is recommended to mimic gastric fluid viscosity during in vitro tablet disintegration studies.

Colonic Function Investigations in Children: Review by the ESPGHAN Motility Working Group

Disorders of colonic motility, most often presenting as constipation, comprise one of the commonest causes of outpatient visits in pediatric gastroenterology. This review, discussed and created by the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Motility Working Group, is a practical guide, which highlights the recent advances in pediatric colonic motility testing including indications, technical principles of the tests, patient preparation, performance and basis of the results' analysis of the tests. classical methods, such as colonic transit time (cTT) with radiopaque markers and colonic scintigraphy, as well as manometry and novel techniques, such as wireless motility capsule and electromagnetic capsule tracking systems are discussed.

Luminal Fluid Motion Inside an In Vitro Dissolution Model of the Human Ascending Colon Assessed Using Magnetic Resonance Imaging

Knowledge of luminal flow inside the human colon remains elusive, despite its importance for the design of new colon-targeted drug delivery systems and physiologically relevant in silico models of dissolution mechanics within the colon. This study uses magnetic resonance imaging (MRI) techniques to visualise, measure and differentiate between different motility patterns within an anatomically representative in vitro dissolution model of the human ascending colon: the dynamic colon model (DCM). The segmented architecture and peristalsis-like contractile activity of the DCM generated flow profiles that were distinct from compendial dissolution apparatuses. MRI enabled different motility patterns to be classified by the degree of mixing-related motion using a new tagging method. Different media viscosities could also be differentiated, which is important for an understanding of colonic pathophysiology, the conditions that a colon-targeted dosage form may be subjected to and the effectiveness of treatments. The tagged MRI data showed that the DCM effectively mimicked wall motion, luminal flow patterns and the velocities of the contents of the human ascending colon. Accurate reproduction of in vivo hydrodynamics is an essential capability for a biorelevant mechanical model of the colon to make it suitable for in vitro data generation for in vitro in vivo evaluation (IVIVE) or in vitro in vivo correlation (IVIVC). This work illustrates how the DCM provides new insight into how motion of the colonic walls may control luminal hydrodynamics, driving erosion of a dosage form and subsequent drug release, compared to traditional pharmacopeial methods.

Mimicking the dynamic Colonic microbiota in vitro to gain a better understanding on the in vivo metabolism of xenobiotics: Degradation of sulfasalazine

Due to the potential effects of colonic metabolism, the interest in the composition and action of intestinal microbiota has increased significantly throughout the last 10 years. Recently focus is turning to the development and implementation of in vitro tools closely simulating in vivo colonic metabolic processes suitable for routine use. The aim of the present study is to compare the metabolization of the model drug sulfasalazine utilizing the novel dynamic bioreactor MimiCol and a standard static batch fermenter inoculated with cryopreserved faecal microbiota. Major advantages of the novel bioreactor MimiCol are the smaller media volume which is closer to in vivo conditions, the possibility to perform media changes and the closer simulation of in vivo mixing patterns. The study proved that the MimiCol is able to simulate the dynamic conditions found within the ascending colon. The dynamic conditions within the MimiCol led to an almost 2-fold increase of the metabolization rate constant in comparison to the static batch fermenter. Our study was able to prove that the novel dynamic bioreactor MimiCol is able to closely simulate physiologically relevant conditions.

Dynamic Colon Model (DCM): A Cine-MRI Informed Biorelevant In Vitro Model of the Human Proximal Large Intestine Characterized by Positron Imaging Techniques

This work used in vivo MRI images of human colon wall motion to inform a biorelevant Dynamic Colon Model (DCM) to understand the interplay of wall motion, volume, viscosity, fluid, and particle motion within the colon lumen. Hydrodynamics and particle motion within the DCM were characterized using Positron Emission Tomography (PET) and Positron Emission Particle Tracking (PEPT), respectively. In vitro PET images showed that fluid of higher viscosity follows the wall motion with poor mixing, whereas good mixing was observed for a low viscosity fluid. PEPT data showed particle displacements comparable to the in vivo data. Increasing fluid viscosity favors the net forward propulsion of the tracked particles. The use of a floating particle demonstrated shorter residence times and greater velocities on the liquid surface, suggesting a surface wave that was moving faster than the bulk liquid. The DCM can provide an understanding of flow motion and behavior of particles with different buoyancy, which in turn may improve the design of drug formulations, whereby fragments of the dosage form and/or drug particles are suspended in the proximal colon.

Ambulatory assessment of colonic motility using the electromagnetic capsule tracking system: Effect of opioids

BACKGROUND

Opioid treatment often causes debilitating constipation. However, it is not well described how opioids affect colonic motility and whether opioid-induced constipation is due to either a decrease of powerful peristaltic contractions or "uncoordinated" peristalsis. The present study aims to investigate the effect of oxycodone on parameters of colonic motility and to determine whether motility is normalized by the opioid antagonist naloxegol.

METHODS

In two randomized, double-blind crossover trials, oxycodone or placebo was administered to 25 healthy males (Trial A), while another 24 healthy males were administered oxycodone with naloxegol or placebo (Trial B). Colonic motility was assessed by tracking the progression of an electromagnetic capsule throughout the large intestine. Segmental colonic transit times and capsule movements were calculated using displacement distance and velocity.

KEY RESULTS

In Trial A, colonic transit time increased during oxycodone treatment compared with placebo (39 vs 18 hours, P < .01). Displacement during long fast antegrade movements was shorter during oxycodone treatment than with placebo (10 vs 20 cm, P = .03). In Trial B, colonic transit time was faster during oxycodone + naloxegol than during oxycodone + placebo (40 vs 55 hours, P = .049), mainly caused by an increase of the percentwise fraction of distance covered by fast movements in the left colon (P = .001).

CONCLUSION & INFERENCES

Oxycodone treatment impaired colonic motility, manifested as increased transit time, specifically decreased long fast antegrade movements, and addition of naloxegol improved motility dynamics. In humans, the increased transit time during opioid treatment is caused by a decrease in long fast movements rather than uncoordinated peristalsis.

Normative values for region-specific colonic and gastrointestinal transit times in 111 healthy volunteers using the 3D-Transit electromagnet tracking system: Influence of age, gender, and body mass index

BACKGROUND

The 3D-Transit electromagnet tracking system (Motilis Medica, SA, Lausanne, Switzerland) is an emerging tool for the ambulatory assessment of gastrointestinal (GI) transit and motility. Using this tool, we aimed to derive normative values for region-specific colonic and GI transit times and to assess the influence of age, gender, and body mass index (BMI).

METHODS

Regional and total colonic transit times (CTT), gastric emptying (GET), small intestinal (SITT), and whole gut (WGTT) transit times were extracted from 111 healthy volunteers from the United Kingdom and Denmark (58 female; median age: 40 years [range: 21-88]). The effects of age, gender, and BMI were assessed using standard statistical methods.

KEY RESULTS

The ascending, transverse, descending, and rectosigmoid colon transit times accounted for 32%, 34%, 17%, and 17% of total CTT in females, and 33%, 25%, 14%, and 28% of total CTT in males. CTT and WGTT were seen to cluster at intervals separated by approximately 24 hours, providing further evidence of the non-continuous nature of these measurements. Increasing age was associated with longer CTT (P = .021), WGTT (P < .001) ascending (P = .004), transverse (P < .001), and total right (P < .001) colon transit times, but shorter rectosigmoid (P = .004) transit time. Female gender was significantly associated with longer transverse (P = .049) and descending (P < .001) colon transit times, but shorter rectosigmoid (P < .001) transit time. Increasing BMI was significantly associated with shorter WGTT (P = .012).

CONCLUSIONS AND INFERENCES

For the first time, normative reference values for region-specific colonic transit have been presented. Age, gender, and BMI were seen to have an effect on transit times.

Imaging Measurement of Whole Gut Transit Time in Paediatric and Adult Functional Gastrointestinal Disorders: A Systematic Review and Narrative Synthesis

BACKGROUND

functional gastrointestinal disorders (FGID) are common conditions in children and adults, often associated with abnormalities of whole gut transit. Currently, transit tests can be performed using several imaging methods, including tracking of radiopaque markers, gamma scintigraphy with the use of radioisotopes, magnetic tracking methods, tracking of movement of wireless motility capsules, and emerging magnetic resonance imaging (MRI) approaches.

OBJECTIVES

to review recent literature on diagnostic imaging techniques used to investigate whole gut transit in FGIDs.

METHODS

a systematic review was carried out. The different techniques are described briefly, with particular emphasis on contemporary literature and new developments, particularly in the field of MRI.

CONCLUSIONS

emerging MRI capsule marker methods are promising new tools to study whole gut transit in FGIDs.

First translational consensus on terminology and definitions of colonic motility in animals and humans studied by manometric and other techniques

Alterations in colonic motility are implicated in the pathophysiology of bowel disorders, but high-resolution manometry of human colonic motor function has revealed that our knowledge of normal motor patterns is limited. Furthermore, various terminologies and definitions have been used to describe colonic motor patterns in children, adults and animals. An example is the distinction between the high-amplitude propagating contractions in humans and giant contractions in animals. Harmonized terminology and definitions are required that are applicable to the study of colonic motility performed by basic scientists and clinicians, as well as adult and paediatric gastroenterologists. As clinical studies increasingly require adequate animal models to develop and test new therapies, there is a need for rational use of terminology to describe those motor patterns that are equivalent between animals and humans. This Consensus Statement provides the first harmonized interpretation of commonly used terminology to describe colonic motor function and delineates possible similarities between motor patterns observed in animal models and humans in vitro (ex vivo) and in vivo. The consolidated terminology can be an impetus for new research that will considerably improve our understanding of colonic motor function and will facilitate the development and testing of new therapies for colonic motility disorders.

Experimental models to study intestinal microbes–mucus interactions in health and disease

A close symbiotic relationship exists between the intestinal microbiota and its host. A critical component of gut homeostasis is the presence of a mucus layer covering the gastrointestinal tract. Mucus is a viscoelastic gel at the interface between the luminal content and the host tissue that provides a habitat to the gut microbiota and protects the intestinal epithelium. The review starts by setting up the biological context underpinning the need for experimental models to study gut bacteria-mucus interactions in the digestive environment. We provide an overview of the structure and function of intestinal mucus and mucins, their interactions with intestinal bacteria (including commensal, probiotics and pathogenic microorganisms) and their role in modulating health and disease states. We then describe the characteristics and potentials of experimental models currently available to study the mechanisms underpinning the interaction of mucus with gut microbes, including in vitro, ex vivo and in vivo models. We then discuss the limitations and challenges facing this field of research.

Ambulatory assessment of colonic motility using the electromagnetic capsule tracking system

BACKGROUND

The Motilis 3D-Transit system tracks electromagnetic capsules as they traverse the gastrointestinal tract. The method is minimally invasive and ambulatory. Analysis has previously been limited to regional gut transit times, but new methods may allow detailed analysis of colonic motility.

METHODS

Parameters of colonic motility were analyzed from 34 3D-Transit recordings performed in healthy volunteers (median age 28 years; 8 F). Characteristic propulsive velocities and lengths of movement were determined to quantify common movement patterns. Data from seven patients with severe chronic diarrhea were included for comparison.

KEY RESULTS

Lack of capsule motion accounted for 82% (75%-87%) of total colonic transit time. Propulsive velocities were distributed with peaks at 0.5 cm/min (antegrade or retrograde) and 50 cm/min (antegrade). Based on velocity and length of propagation, five motor patterns were identified; (a) long fast antegrade, (b) fast antegrade, (c) slow antegrade, (d) slow retrograde, and (e) fast retrograde movements. Long fast antegrade movements were median 21 cm (10-96 cm). Capsule progression was faster during daytime than at night (5.9 cm/h vs 0.8 cm/h; P < 0.01). Colonic transit was faster in patients with chronic diarrhea than in healthy volunteers (5.4 h vs 18.2 h; P = 0.04), with higher capsule velocity (20.4 cm/h vs 4.4 cm/h; P < 0.01).

CONCLUSIONS AND INFERENCES

The 3D-Transit system now allows detailed description of colonic motility and our results are supported by those previously suggested by manometry. It holds promise for future assessment of movement patterns to characterize different diseases and effects of treatment.

Technical report: Inter- and intra-rater reliability of regional gastrointestinal transit times measured using the 3D-Transit electromagnet tracking system

BACKGROUND

The 3D-Transit electromagnet tracking system is an emerging tool for the ambulatory assessment of gastrointestinal (GI) transit times and motility patterns, based on the anatomical localization of ingestible electromagnetic capsules. Currently, 3D-Transit recordings are manually analyzed to extract GI transit times. As this is a subjective method, there is some inherent variability in the measurements, which may be experience-dependent. We therefore assessed inter- and intra-rater reliability of GI transit times from 3D-Transit recordings.

METHODS

Thirty-six 3D-Transit recordings (17 female; median age: 34 years [range: 21-80]) were analyzed twice by 3 raters with varying experience. Each rater manually identified the timestamps when a capsule progressed from antrum to duodenum, and from ileum to right colon. These timestamps, along with the ingestion and expulsion times, were used to determine whole gut (WGTT), gastric emptying (GET), small intestinal (SITT) and colonic (CTT) transit times. Reliability was determined using interclass correlation coefficients (ICCs).

KEY RESULTS

For capsule progression timestamps, the most and mid-experienced raters had fair to good inter- and excellent intra-rater reliability (ICC_min-max  = 0.61-1.00), whereas the inexperienced rater had poor to fair inter- and poor intra-rater reliability (ICC_min-max  = 0.28-0.55). GET and SITT reliability between the most and mid-experienced raters was fair (ICC_min-max  = 0.61-0.73), while reliability between these raters and the inexperienced rater was poor to fair (ICC_min-max  = 0.28-0.55). CTT reliability was excellent between and within all raters (ICC_min-max  = 0.92-0.99).

CONCLUSIONS & INFERENCES

Inexperienced raters provide the least reliable measurements from 3D-Transit recordings, which confirms requirement for adequate training. Automation may improve the reliability of measurements.

Gut Movements: A Review of the Physiology of Gastrointestinal Transit

The well-regulated mechanisms of intestinal transit favor aboral movement of intestinal contents during the formation of normal stool. Electrical pacemakers initiate mechanical smooth muscular propulsion under regulation by the enteric nervous system-a function of the "brain-gut axis." Several unique intestinal motor patterns function in concert to enhance the activities of intestinal transit. Development of pharmacologic targets of intestinal transit mechanisms afford clinicians control in the management of functional gastrointestinal disorders. This review highlights the important physiologic events of intestinal transit, discusses selected pharmacologic and neuromodulators involved in these processes, and provides relevant clinical correlates to physiologic events.

Colonic motor response to wakening is blunted in slow transit constipation as detected by wireless motility capsule

Background

Chronic constipation may be categorized as normal transit (NTC), slow transit (STC), or outlet obstruction. Colonic wake response is a relative increase in colonic motility upon awakening. Colonic manometry studies have demonstrated attenuated wake response in STC. We sought to evaluate wake response among healthy (H), NTC, and STC patients using wireless motility capsule (WMC).

Methods

A retrospective study of WMC data from a multicenter clinical trial and a tertiary gastroenterology clinic was performed. WMC motility parameters of contraction frequency (Ct) and area under the contraction curve (AUC) were analyzed in 20-min windows 1-h before and after awakening. T-tests compared parameters between H, NTC, and STC. Linear regression analysis was performed to determine if outlet obstruction confounded data. A receiver operating characteristic curve demonstrated optimal Ct cut-offs to define blunted wake response.

Results

A total of 62 H, 53 NTC and 75 STC subjects were analyzed. At 20, 40, and 60 min after awakening, STC subjects had significantly lower mean Ct when compared to H (p < 0.001) and NTC (p < 0.01). Linear regression demonstrated that outlet obstruction was not associated with a decreased wake response (β = 3.94, (CI −3.12–1.00), P = 0.27). Defined at the Ct threshold of 64 at 20-min post-wake, blunted wake response sensitivity was 84% and specificity was 32% for chronic constipation.

Conclusion

Findings of an impaired wake response in subjects with STC and not NTC adds further evidence to neuronal dysfunction as an etiology of STC, and identifies a possible temporal target for pharmacologic intervention.

Colonic transit time and pressure based on Bernoulli's principle

PURPOSE

Variations in the caliber of human large intestinal tract causes changes in pressure and the velocity of its contents, depending on flow volume, gravity, and density, which are all variables of Bernoulli's principle. Therefore, it was hypothesized that constipation and diarrhea can occur due to changes in the colonic transit time (CTT), according to Bernoulli's principle. In addition, it was hypothesized that high amplitude peristaltic contractions (HAPC), which are considered to be involved in defecation in healthy subjects, occur because of cecum pressure based on Bernoulli's principle.

METHODS

A virtual healthy model (VHM), a virtual constipation model and a virtual diarrhea model were set up. For each model, the CTT was decided according to the length of each part of the colon, and then calculating the velocity due to the cecum inflow volume. In the VHM, the pressure change was calculated, then its consistency with HAPC was verified.

RESULTS

The CTT changed according to the difference between the cecum inflow volume and the caliber of the intestinal tract, and was inversely proportional to the cecum inflow volume. Compared with VHM, the CTT was prolonged in the virtual constipation model, and shortened in the virtual diarrhea model. The calculated pressure of the VHM and the gradient of the interlocked graph were similar to that of HAPC.

CONCLUSION

The CTT and HAPC can be explained by Bernoulli's principle, and constipation and diarrhea may be fundamentally influenced by flow dynamics.

Colorectal Transit and Volume During Treatment With Prolonged-release Oxycodone/Naloxone Versus Oxycodone Plus Macrogol 3350

BACKGROUND/AIMS

Opioid-induced constipation (OIC) is the most common gastrointestinal (GI) side effect to opioid treatment. Opioid receptor antagonists against OIC have been introduced, but their efficacy has not been directly compared to conventional laxatives. Our aim was to compare symptoms and objective parameters of gut function in an experimental model of OIC during treatment with the opioid antagonist naloxone and oxycodone in prolonged-release (PR) formulation versus oxycodone plus macrogol 3350.

METHODS

In this randomized, double-blind, crossover trial 20 healthy men received a 5-day treatment of combined PR oxycodone/naloxone or PR oxycodone plus macrogol 3350. Regional GI transit times and segmental colorectal transit were assessed with the Motilis 3D-Transit electromagnetic capsule system. Colorectal volumes were determined by MRI. OIC symptoms were assessed with validated questionnaires, along with stool frequency and consistency.

RESULTS

Total colorectal volume did not change after 5 days' treatment with PR oxycodone/naloxone (941 vs 1036 mL; P = 0.091), but increased significantly after PR oxycodone plus macrogol treatment (912 vs 1123 mL; P < 0.001). Neither regional GI transit times nor segmental colorectal transit differed between the treatments (all P > 0.05). The Patient Assessment of Constipation Symptom Questionnaire abdominal symptoms score was lower during PR oxycodone/naloxone compared to PR oxycodone plus macrogol (0.2 vs 3.2; P = 0.002). Stool frequency was lower during PR oxycodone/naloxone compared to PR oxycodone plus macrogol (4.2 vs 5.4; P = 0.035).

CONCLUSIONS

PR oxycodone plus macrogol increases colorectal volume, but does not improve GI transit compared to PR oxycodone/naloxone. However, PR oxycodone/naloxone results in a lower abdominal symptom burden, despite higher stool frequency during macrogol treatment.

Chronic constipation

Chronic constipation is a prevalent condition that severely impacts the quality of life of those affected. Several types of primary chronic constipation, which show substantial overlap, have been described, including normal-transit constipation, rectal evacuation disorders and slow-transit constipation. Diagnosis of primary chronic constipation involves a multistep process initiated by the exclusion of 'alarm' features (for example, unintentional weight loss or rectal bleeding) that might indicate organic diseases (such as polyps or tumours) and a therapeutic trial with first-line treatments such as dietary changes, lifestyle modifications and over-the-counter laxatives. If symptoms do not improve, investigations to diagnose rectal evacuation disorders and slow-transit constipation are performed, such as digital rectal examination, anorectal structure and function testing (including the balloon expulsion test, anorectal manometry or defecography) or colonic transit tests (such as the radiopaque marker test, wireless motility capsule test, scintigraphy or colonic manometry). The mainstays of treatment are diet and lifestyle interventions, pharmacological therapy and, rarely, surgery. This Primer provides an introduction to the epidemiology, pathophysiological mechanisms, diagnosis, management and quality of life associated with the commonly encountered clinical problem of chronic constipation in adults unrelated to opioid abuse.

Assessment of colorectal length using the electromagnetic capsule tracking system: a comparative validation study in healthy subjects

AIM

We aimed to determine colorectal length with the 3D-Transit system by describing a 'centreline' of capsule movement and comparing it with known anatomy, as determined by magnetic resonance imaging (MRI). Further, we aimed to test the day-to-day variation of colorectal length assessed with the system.

METHOD

The 3D-Transit system consists of electromagnetic capsules that can be tracked as they traverse the gastrointestinal tract. Twenty-five healthy subjects were examined with both 3D-Transit and MRI. Another 21 healthy subjects were examined with 3D-Transit on two consecutive days.

RESULTS

Computation of colorectal length from capsule passage was possible for 60 of the 67 3D-Transit recordings. The length of the colorectum measured with MRI and 3D-Transit was 95 (75-153) cm and 99 (77-147) cm, respectively (P = 0.15). The coefficient of variation (CV) between MRI and 3D-Transit was 7.8%. Apart from the caecum/ascending colon being 26% (P = 0.002) shorter on MRI, there were no other differences in total or segmental colorectal lengths between methods (all P > 0.05). The length of the colorectum measured with 3D-Transit on two consecutive days was 102 (73-119) cm and 103 (75-123) cm (P = 0.67). The CV between days was 7.3%.

CONCLUSION

The 3D-Transit system allows accurate and reliable determination of colorectal length compared with MRI-derived colorectal length and between days. Antegrade or retrograde capsule movement relative to this centreline, as well as the length and speed of movements, may be determined by future studies to allow better classification and treatment in patients with dysmotility.

Recording In Vivo Human Colonic Motility: What Have We Learnt Over the Past 100 Years?

To understand the abnormalities that underpin functional gut disorders we must first gain insight into the normal patterns of gut motility. While detailed information continually builds on the motor patterns (and mechanisms that control them) of the human esophagus and anorectum, our knowledge of normal and abnormal motility in the more inaccessible regions of the gut remains poor. This particularly true of the human colon. Investigation of in vivo colonic motor patterns is achieved through measures of transit (radiology, scintigraphy and, more recently, "smart pills") or by direct real-time recording of colonic contractility (intraluminal manometry). This short review will provide an overview of findings from the past and present and attempt to piece together the complex nature of colonic motor patterns. In doing so it will build a profile of human colonic motility and determine the likely mechanisms that control this motility.

Clinical application of a gadolinium-based capsule as an MRI contrast agent in slow transit constipation diagnostics

BACKGROUND

As a traditional method for the assessment of colon dynamics, radio-opaque markers (ROMs) are limited in clinical use because of their ionizing radiation. We compared the accuracy and applicability of gadolinium-based capsules with ROMs in the measurement of colon dynamics in healthy controls and slow transit constipation (STC) patients.

METHODS

Seven patients with STC and nine healthy controls under a normal diet orally consumed ROMs and gadolinium-based capsules simultaneously. All subjects underwent X-ray and magnetic resonance imaging (MRI). Healthy control images were acquired at 12, 24, and 48 h, and STC patient images were acquired at 24, 48, and 72 h. The scores based on the position of the labeling capsules and ROMs in the colon and the colon transit times (CTTs) in the two groups were compared.

KEY RESULTS

The CTTs obtained via the ROMs were 34.7±17.4 and 67.3±6.5 h in the healthy controls and STC patients, respectively (P<.05). The CTTs obtained via MRI were 30.9±15.9 and 74.1±7.2 h in the healthy controls and STC patients, respectively (P<.05). The CTTs of the STC patients were significantly longer than the healthy controls. The correlation (r_s ) between the scores based on the position of the labeling capsule and ROMs in the healthy group and the STC patients was .880 (P<.05) and .889 (P<.05), respectively.

CONCLUSIONS AND INFERENCES

As a MRI contrast label, gadolinium-based capsules exhibit results comparable to ROMs in colon motility measurements.

The Impact of Opioid Treatment on Regional Gastrointestinal Transit

Background/Aims

To employ an experimental model of opioid-induced bowel dysfunction in healthy human volunteers, and evaluate the impact of opioid treatment compared to placebo on gastrointestinal (GI) symptoms and motility assessed by questionnaires and regional GI transit times using the 3-dimensional (3D)-Transit system.

Methods

Twenty-five healthy males were randomly assigned to oxycodone or placebo for 5 days in a double blind, crossover design. Adverse GI effects were measured with the bowel function index, gastrointestinal symptom rating scale, patient assessment of constipation symptom questionnaire, and Bristol stool form scale. Regional GI transit times were determined using the 3D-Transit system, and segmental transit times in the colon were determined using a custom Matlab^® graphical user interface.

Results

GI symptom scores increased significantly across all applied GI questionnaires during opioid treatment. Oxycodone increased median total GI transit time from 22.2 to 43.9 hours (P < 0.001), segmental transit times in the cecum and ascending colon from 5.7 to 9.9 hours (P = 0.012), rectosigmoid colon transit from 2.7 to 9.0 hours (P = 0.044), and colorectal transit time from 18.6 to 38.6 hours (P = 0.001). No associations between questionnaire scores and segmental transit times were detected.

Conclusions

Self-assessed GI adverse effects and increased GI transit times in different segments were induced during oxycodone treatment. This detailed information about segmental changes in motility has great potential for future interventional head-to-head trials of different laxative regimes for prevention and treatment of constipation.

A composite fibre optic catheter for monitoring peristaltic transit of an intra-luminal bead

A fibre optic motion sensor has been developed for monitoring the proximity and direction of motion of a ferrous bead travelling axial to the sensor. By integrating an array of these sensors into our previously developed fibre optic manometry catheters we demonstrate simultaneous detection of peristaltic muscular activity and the associated motion of ferrous beads through a colonic lumen. This allows the motion of solid content to be temporally and spatially related to pressure variations generated by peristaltic contractions without resorting to videoflouroscopy to track the motion of a radio opaque bolus. The composite catheter has been tested in an in-vitro animal preparation consisting of excised sections of rabbit colon. Cut-away image of the fibre optic motion sensor showing the location of the fibre Bragg gratings and the rare earth magnet.

Colon wall motility: comparison of novel quantitative semi-automatic measurements using cine MRI

BACKGROUND

Recently, cine magnetic resonance imaging (MRI) has shown promise for visualizing movement of the colonic wall, although assessment of data has been subjective and observer dependent. This study aimed to develop an objective and semi-automatic imaging metric of ascending colonic wall movement, using image registration techniques.

METHODS

Cine balanced turbo field echo MRI images of ascending colonic motility were acquired over 2 min from 23 healthy volunteers (HVs) at baseline and following two different macrogol stimulus drinks (11 HVs drank 1 L and 12 HVs drank 2 L). Motility metrics derived from large scale geometric and small scale pixel movement parameters following image registration were developed using the post ingestion data and compared to observer grading of wall motion. Inter and intra-observer variability in the highest correlating metric was assessed using Bland-Altman analysis calculated from two separate observations on a subset of data.

KEY RESULTS

All the metrics tested showed significant correlation with the observer rating scores. Line analysis (LA) produced the highest correlation coefficient of 0.74 (95% CI: 0.55-0.86), p < 0.001 (Spearman Rho). Bland-Altman analysis of the inter- and intra-observer variability for the LA metric, showed almost zero bias and small limits of agreement between observations (-0.039 to 0.052 intra-observer and -0.051 to 0.054 inter-observer, range of measurement 0-0.353).

CONCLUSIONS & INFERENCES

The LA index of colonic motility derived from cine MRI registered data provides a quick, accurate and non-invasive method to detect wall motion within the ascending colon following a colonic stimulus in the form of a macrogol drink.

Regional Gastrointestinal Transit Times in Patients With Carcinoid Diarrhea: Assessment With the Novel 3D-Transit System

Background/Aims

The paucity of knowledge regarding gastrointestinal motility in patients with neuroendocrine tumors and carcinoid diarrhea restricts targeted treatment. 3D-Transit is a novel, minimally invasive, ambulatory method for description of gastrointestinal motility. The system has not yet been evaluated in any group of patients. We aimed to test the performance of 3D-Transit in patients with carcinoid diarrhea and to compare the patients’ regional gastrointestinal transit times (GITT) and colonic motility patterns with those of healthy subjects.

Methods

Fifteen healthy volunteers and seven patients with neuroendocrine tumor and at least 3 bowel movements per day were investigated with 3D-Transit and standard radiopaque markers.

Results

Total GITT assessed with 3D-Transit and radiopaque markers were well correlated (Spearman’s rho = 0.64, P = 0.002). Median total GITT was 12.5 (range: 8.5–47.2) hours in patients versus 25.1 (range: 13.1–142.3) hours in healthy (P = 0.007). There was no difference in gastric emptying (P = 0.778). Median small intestinal transit time was 3.8 (range: 1.4–5.5) hours in patients versus 4.4 (range: 1.8–7.2) hours in healthy subjects (P = 0.044). Median colorectal transit time was 5.2 (range: 2.9–40.1) hours in patients versus 18.1 (range: 5.0–134.0) hours in healthy subjects (P = 0.012). Median frequency of pansegmental colonic movements was 0.45 (range: 0.03–1.02) per hour in patients and 0.07 (range: 0–0.61) per hour in healthy subjects (P = 0.045).

Conclusions

Three-dimensional Transit allows assessment of regional GITT in patients with diarrhea. Patients with carcinoid diarrhea have faster than normal gastrointestinal transit due to faster small intestinal and colorectal transit times. The latter is caused by an increased frequency of pansegmental colonic movements.

Pilot study trialling a new ambulatory method for the clinical assessment of regional gastrointestinal transit using multiple electromagnetic capsules

BACKGROUND

Gastrointestinal (GI) motor disorders often involve several regions of the GI tract. Therefore, easy and safe assessment of whole gut and regional motility is valuable for more precise diagnosis. 3D-Transit is a novel method for ambulatory evaluation of total and regional gastrointestinal transit times (GITT) based on the anatomical localization of ingestible electromagnetic capsules. The main purpose of this study was to test the performance of the 3D-Transit system.

METHODS

Twenty healthy volunteers each ingested three electromagnetic capsules over a period of two consecutive days. Standard radio-opaque markers (ROM) were also ingested to assess the agreement between total GITT obtained with both methods.

KEY RESULTS

Investigations were well-tolerated and three capsules could be tracked simultaneously with minimal data loss (Capsule 1: median: 0.2% of time (range 0-25.3%). Region specific contraction patterns were identified and used for computation of total and regional GITT in all subjects. Inter-observer agreement was 100% for total GITT (median variation 0%) but less for regional GITT. Day-to-day and diurnal variations were significant for total and regional GITT. Total GITT assessed by 3D-Transit capsules were moderately well-correlated to those assessed with standard ROM (Spearman's rho = 0.7).

CONCLUSIONS & INFERENCES

3D-transit is a well-tolerated and minimal invasive ambulatory method for assessment of GI motility. By providing both total and regional transit times, the 3D-Transit system holds great promise for future clinical studies of GI function in health and disease.

Quantification of in vivo colonic motor patterns in healthy humans before and after a meal revealed by high-resolution fiber-optic manometry

BACKGROUND

Until recently, investigations of the normal patterns of motility of the healthy human colon have been limited by the resolution of in vivo recording techniques.

METHODS

We have used a new, high-resolution fiber-optic manometry system (72 sensors at 1-cm intervals) to record motor activity from colon in 10 healthy human subjects.

KEY RESULTS

In the fasted colon, on the basis of rate and extent of propagation, four types of propagating motor pattern could be identified: (i) cyclic motor patterns (at 2-6/min); (ii) short single motor patterns; (iii) long single motor patterns; and (iv) occasional retrograde, slow motor patterns. For the most part, the cyclic and short single motor patterns propagated in a retrograde direction. Following a 700 kCal meal, a fifth motor pattern appeared; high-amplitude propagating sequences (HAPS) and there was large increase in retrograde cyclic motor patterns (5.6 ± 5.4/2 h vs 34.7 + 19.8/2 h; p < 0.001). The duration and amplitude of individual pressure events were significantly correlated. Discriminant and multivariate analysis of duration, gradient, and amplitude of the pressure events that made up propagating motor patterns distinguished clearly two types of pressure events: those belonging to HAPS and those belonging to all other propagating motor patterns.

CONCLUSIONS & INFERENCES

This work provides the first comprehensive description of colonic motor patterns recorded by high-resolution manometry and demonstrates an abundance of retrograde propagating motor patterns. The propagating motor patterns appear to be generated by two independent sources, potentially indicating their neurogenic or myogenic origin.

Clinical potential of naloxegol in the management of opioid-induced bowel dysfunction

Opioid-induced bowel dysfunction (OIBD) is a burdensome condition which limits the therapeutic benefit of analgesia. It affects the entire gastrointestinal tract, predominantly by activating opioid receptors in the enteric nervous system, resulting in a wide range of symptoms, such as reflux, bloating, abdominal cramping, hard, dry stools, and incomplete evacuation. The majority of studies evaluating OIBD focus on constipation experienced in approximately 60% of patients. Nevertheless, other presentations of OIBD seem to be equally frequent. Furthermore, laxative treatment is often insufficient, which in many patients results in decreased quality of life and discontinuation of opioid treatment. Novel mechanism-based pharmacological approaches targeting the gastrointestinal opioid receptors have been marketed recently and even more are in the pipeline. One strategy is prolonged release formulation of the opioid antagonist naloxone (which has limited systemic absorption) and oxycodone in a combined tablet. Another approach is peripherally acting, μ-opioid receptor antagonists (PAMORAs) that selectively target μ-opioid receptors in the gastrointestinal tract. However, in Europe the only PAMORA approved for OIBD is the subcutaneously administered methylnaltrexone. Alvimopan is an oral PAMORA, but only approved in the US for postoperative ileus in hospitalized patients. Finally, naloxegol is a novel, oral PAMORA expected to be approved soon. In this review, the prevalence and pathophysiology of OIBD is presented. As PAMORAs seem to be a promising approach, their potential effect is reviewed with special focus on naloxegol's pharmacological properties, data on safety, efficacy, and patient-focused perspectives. In conclusion, as naloxegol is administered orally once daily, has proven efficacious compared to placebo, has an acceptable safety profile, and can be used as add-on to existing pain treatment, it is a welcoming addition to the targeted treatment possibilities for OIBD.

A randomised, controlled study of small intestinal motility in patients treated with sacral nerve stimulation for irritable bowel syndrome

Background

Irritable bowel syndrome (IBS) is among the most common gastrointestinal disorders worldwide. In selected patients with severe diarrhoea-predominant or mixed IBS subtypes sacral nerve stimulation (SNS) alleviates IBS-specific symptoms and improves quality of life. The mode of action, however, remains unknown. The present study aimed to evaluate the effect of SNS on small intestinal motility in IBS patients.

Methods

Twenty patients treated with SNS for severe diarrhoea-predominant or mixed IBS were included in a randomised, controlled, crossover study. The neurostimulator was turned ON or OFF for the first one month and then to the opposite setting for the next month. Gastrointestinal transit patterns were investigated with the Motility Tracking System-1 (MTS-1) at the end of each the ON and OFF period. Primary endpoint was change in the velocity of the magnetic pill within the small intestine. Statistical testing was performed with Wilcoxon’s rank sum test and Fisher’s exact test.

Results

The median velocity of the magnetic pill through the small intestine in the fasting state was not significantly different between periods with and without SNS (Group ON-OFF: median change 0 m/h (range -1.07, 0.63), Group OFF-ON: median change 0.27 m/h (range -0.59, 1.12)) (p = 0.25). Neither, was the median velocity of the magnetic pill through the small intestine in the postprandial state significantly different between periods with and without SNS (Group ON-OFF: median change -0.13 m/h (range -0.46, 0.23), Group OFF-ON: median change 0.015 m/h (range -0.48, 0.59)) (p = 0.14).

Conclusion

Even though SNS may reduce symptoms of diarrhoea-predominant and mixed IBS, it has no detectable effect on small intestinal transit patterns.

Trial registration

Clinical.trials.gov, (NCT00919672).

Magnet tracking allows assessment of regional gastrointestinal transit times in children

Background

Data on small intestinal transit time in healthy children are lacking, and normal values for gastric emptying and colonic transit time are sparse. Conventional methods, including radiopaque markers, scintigraphy, and PillCam™ involve radiation or require the child to swallow a large pill. The minimally invasive, radiation-free Motility Tracking System-1 (MTS-1) has been introduced for description of gastrointestinal motility in adults. The aim of the study was to evaluate the MTS-1 for assessment of gastrointestinal transit times and motility patterns in healthy children.

Methods

Twenty-one healthy children (nine girls), median age 10 (range 7–12) years were included. For evaluation with MTS-1, a small magnetic pill was ingested and tracked through the gastrointestinal tract by a matrix of 16 magnetic sensors placed behind a nonmagnetic bed. The children were investigated for 8 hours after swallowing the magnetic pill and again for 4 hours the following morning. After leaving the unit, each child came back after every bowel movement to determine if the pill had been expelled.

Results

Nineteen children could swallow the pill. Characteristic contraction patterns were identified for the stomach (three per minute), small intestine (9–11 per minute), and colon (4–5 per minute). Median total gastrointestinal transit time was 37.7 (range 9.5–95.8) hours, median gastric emptying time was 37 (range 2–142) minutes, median small intestinal transit time was 302 (range 164 to >454) minutes, and median colorectal transit time was 38.1 (range 5.6–90.0) hours.

Conclusion

MTS-1 allows minimally invasive evaluation of gastrointestinal motility in children. Use of the method is, however, restricted by the nonambulatory setup.

The effect of sacral nerve stimulation on distal colonic motility in patients with faecal incontinence

BACKGROUND

Sacral nerve stimulation (SNS) is an effective treatment for neurogenic faecal incontinence (FI). However, the clinical improvement that patients experience cannot be explained adequately by changes in anorectal function. The aim of this study was to examine the effect of SNS on colonic propagating sequences (PSs) in patients with FI in whom urgency and incontinence was the predominant symptom.

METHODS

In patients with FI a high-resolution fibre-optic manometry catheter, containing 90 sensors spaced at 1-cm intervals, was positioned colonoscopically and clipped to the caecum. A unipolar or quadripolar tined electrode was implanted into the S3 sacral nerve foramen. Colonic manometry was evaluated in a double-blind randomized crossover trial, using true suprasensory stimulation or sham stimulation. Each stimulation period, lasting 2 h, was preceded by a 2-h basal manometric recording.

RESULTS

All 11 patients studied showed a colonic response to SNS. In ten patients there was a significant increase in the frequency of retrograde PSs throughout the colon during true stimulation compared with sham stimulation (P = 0·014). In one outlier, with baseline retrograde PS frequency nine times that of the nearest patient, a reduction in retrograde PS frequency was recorded. Compared with sham stimulation, SNS had no effect on the frequency of antegrade PSs or high-amplitude PSs.

CONCLUSION

SNS modulates colonic motility in patients with faecal urge incontinence. These data suggest that SNS may improve continence and urgency through alteration of colonic motility, particularly by increasing retrograde PSs in the left colon.

Opioid-induced bowel dysfunction: pathophysiology and management

Opioids are the most commonly prescribed medications to treat severe pain in the Western world. It has been estimated that up to 90% of American patients presenting to specialized pain centres are treated with opioids. Along with their analgesic properties, opioids have the potential to produce substantial side effects, such as nausea, cognitive impairment, addiction and urinary retention. In the gut, opioids exert their action on the enteric nervous system, where they bind to the myenteric and submucosal plexuses, causing dysmotility, decreased fluid secretion and sphincter dysfunction, which all leads to opioid-induced bowel dysfunction (OIBD). In the clinic, this is reported as nausea, vomiting, gastro-oesophageal reflux-related symptoms, constipation, etc. One of the most severe symptoms is constipation, which can be assessed using different scales for subjective assessment. Objective methods such as radiography and colonic transit time can also be used, together with manometry and evaluation of anorectal function to explore the pathophysiology. Dose-limiting adverse symptoms of OIBD can lead to insufficient pain treatment. Even though several treatment strategies are available, the side effects are still a major challenge. Traditional laxatives are normally prescribed but they are often insufficient to alleviate symptoms, especially those from the upper gastrointestinal tract. Newer prokinetics, such as prucalopride and lubiprostone, may be more effective in alleviating OIBD. Another treatment approach is co-administration of opioid antagonists, which either cannot cross the blood-brain barrier or selectively target opioid receptors in the gastrointestinal tract. However, although these new agents have proved to be more efficacious than placebo, clinical trials still need to prove their superiority to standard co-prescribed laxative regimes.

Turning off sacral nerve stimulation does not affect gastric and small intestinal motility in patients treated for faecal incontinence

AIM

Sacral nerve stimulation (SNS) reduces symptoms in up to 80% of patients with faecal incontinence (FI). Its effects are not limited to the distal colon and the pelvic floor. Accordingly, spinal or supraspinal neuromodulation have been suggested as part of the mode of action. The effect of SNS on gastric and small-intestinal motility was studied.

METHOD

Using the magnet tracking system, MTS-1, a small magnetic pill was tracked twice through the upper gastrointestinal tract of eight patients with FI successfully treated with SNS. Following a randomized double-blind crossover design, the stimulator was either left active or was turned off for 1 week before investigations with MTS-1.

RESULTS

The median (range) frequency of gastric con-tractions was 3.05 (2.83-3.40) per min during SNS and 3.04 (2.79?-3.76) per min without (P=NS). The median (range) frequency of contractions in the small intestine during the first 2h after pyloric passage was 10.005 (9.68-10.70) per min during SNS and 10.09 (9.79-10.29) per min without SNS (P=NS). The median (range) velocity of the magnetic pill during the first 2h in the small intestine was 1.6 (1.2-2.8) cm/min during SNS and 1.7 (0.8-3.7) cm/min without SNS (P=NS). Small-intestinal propagation mainly occurred during very fast movements (>15cm/min), accounting for 51% (42-60%) of the distance 3% (2-4%) of the time during SNS and for 53% (18-73%) of the distance 3% (1-8%) of the time without SNS (P=NS).

CONCLUSION

Turning off SNS for 1week did not affect gastric or small-intestinal motility patterns.

Myogenic regional responsiveness to cholinergic and vipergic stimulation in human colon

BACKGROUND

Differences in the actions of enteric neurotransmitters on colonic circular and longitudinal muscle layers have not been clearly determined, nor the possible existence of intrinsic myogenic phenotypes that might contribute to regional differences in human colon motor activity. The aim of this study was to analyze the direct pharmaco-mechanical coupling of carbachol (CCh) and vasoactive intestinal polypeptide (VIP) on human colonic smooth muscle strips and cells.

METHODS

Circular and longitudinal muscle strips and cells were obtained from 15 human specimens of ascending and sigmoid colon. Both isometric tension on muscle strips and contraction and relaxation on cells were measured in response to increasing CCh and VIP concentrations.

KEY RESULTS

Circular muscle strips of ascending colon were more sensitive to the effect of CCh than that of sigmoid colon, EC(50) values being, respectively, 4.15μmolL(-1) and 8.47μmolL(-1) (P<0.05), although there were no differences in maximal responses. No regional differences were observed in longitudinal muscle strips or in smooth muscle cells. Maximal responses to CCh were higher on circular than longitudinal muscle strips and cells throughout the colon. A greater sensitivity to VIP was observed in ascending colon compared with sigmoid colon, both in circular (EC(50:) 0.041 and 0.15μmolL(-1) , respectively, P<0.01) and longitudinal (EC(50:) 0.043 and 0.09μmolL(-1) , respectively, P<0.05) strips, and similar differences were observed in longitudinal smooth muscle cells (EC(50:) 44.85 and 75.24nmolL(-1) , respectively, P<0.05).

CONCLUSIONS & INFERENCES

Regional myogenic differences in pharmaco-mechanical coupling between the enteric neurotransmitters and smooth muscle contribute to the complex regional motor patterns of human colon.

Gastric transit and small intestinal transit time and motility assessed by a magnet tracking system

Background

Tracking an ingested magnet by the Magnet Tracking System MTS-1 (Motilis, Lausanne, Switzerland) is an easy and minimally-invasive method to assess gastrointestinal transit. The aim was to test the validity of MTS-1 for assessment of gastric transit time and small intestinal transit time, and to illustrate transit patterns detected by the system.

Methods

A small magnet was ingested and tracked by an external matrix of 16 magnetic field sensors (4 × 4) giving a position defined by 5 coordinates (position: x, y, z, and angle: θ, ϕ). Eight healthy subjects were each investigated three times: (1) with a small magnet mounted on a capsule endoscope (PillCam); (2) with the magnet alone and the small intestine in the fasting state; and (3) with the magnet alone and the small intestine in the postprandial state.

Results

Experiment (1) showed good agreement and no systematic differences between MTS-1 and capsule endoscopy when assessing gastric transit (median difference 1 min; range: 0-6 min) and small intestinal transit time (median difference 0.5 min; range: 0-52 min). Comparing experiments (1) and (2) there were no systematic differences in gastric transit or small intestinal transit when using the magnet-PillCam unit and the much smaller magnetic pill. In experiments (2) and (3), short bursts of very fast movements lasting less than 5% of the time accounted for more than half the distance covered during the first two hours in the small intestine, irrespective of whether the small intestine was in the fasting or postprandial state. The mean contraction frequency in the small intestine was significantly lower in the fasting state than in the postprandial state (9.90 min^-1 vs. 10.53 min^-1) (p = 0.03).

Conclusion

MTS-1 is reliable for determination of gastric transit and small intestinal transit time. It is possible to distinguish between the mean contraction frequency of small intestine in the fasting state and in the postprandial state.

Gastrointestinal transit in patients with systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis and collagen deposits. Gastrointestinal symptoms of SSc, including abdominal pain, bloating and discomfort, are common but diffuse and their pathophysiology remains obscure.

AIM

To investigate the pathophysiology of abdominal pain and discomfort in individuals with SSc.

METHODS

A total of 15 individuals with SSc (13 women, median age 58 years), all suffering from diffuse abdominal symptoms, and 17 healthy volunteers (12 women, median age 52 years) were evaluated with the Motility Tracking System, MTS-1, measuring gastric emptying (GE) and velocity through the small intestine. SSc patients were also examined for bacterial overgrowth using the hydrogen breath test and with radiopaque markers to determine the total gastrointestinal transit time (GITT).

RESULTS

Assessed with the MTS-1, the velocity through the proximal small intestine was significantly reduced in SSc patients (median 0.525 m/h, range 0.11-1.15) when compared to healthy subjects (median 0.91 m/h, range 0.51-1.74) (p = 0.02). Prolonged GE was found in 4 SSc patients (27%) but in none of the healthy volunteers (p = 0.04). Only 3 SSc patients (21%) had positive breath tests for small intestinal bacterial overgrowth. GITT was >3 days in 8 patients (53%). Slow small intestinal transit was associated with a prolonged GITT (p < 0.05).

CONCLUSION

Velocity through the small intestine is significantly reduced in SSc patients with diffuse abdominal symptoms.

Visualization and quantification of intestinal transit and motor function by real-time tracking of 19F labeled capsules in humans

A combined (19)F and (1)H MRI framework for the assessment of human intestinal transit and motor function is presented. This framework consists of silicone coated polychlorotrifluoroethylene capsules filled with perfluoro-[15]-crown-5-ether as (19)F marker, a flexible (19)F surface coil and a (19)F projection imaging sequence, allowing for real-time tracking of a single or multiple capsules. The capsules (length 11.5 mm, Ø 7.2 mm) contain 140 μL perfluoro-[15]-crown-5-ether and were tested for cytotoxicity and leakage prior to oral administration. A balanced SSFP projection sequence was implemented, yielding a temporal resolution of 133 ms. Optional multi-frequency excitation, allowing for interleaved tracking of differently labeled (19)F capsules, was incorporated. The passage of the (19)F capsules through intestinal sections was monitored in two healthy volunteers. Capsule coordinates were successfully coregistered with anatomical reference scans. Intestinal motility, residence times, lengths and forward velocities were determined. Simultaneous tracking of two capsules allowed for the assessment of peristaltic patterns with correction for respiratory motion. By providing the means for real-time multiple capsule tracking and high resolution anatomical imaging, the presented multinuclear imaging framework has the potential to provide important supplemental information for physiological and pharmaceutical research.

Colon carcinoma--classification into right and left sided cancer or according to colonic subsite?--Analysis of 29,568 patients

BACKGROUND

It is common to distinguish between right and left colon cancer (RCC and LCC). But, little is known about the influence of its exact location on the tumor stage and characteristics when considering the colonic subsite within the right or left colon.

METHODS

During a five-year period, 29,568 consecutive patients were evaluated by data from the German multi-centered observational study "Colon/Rectal Carcinoma". Patients were split into 7 groups, each group representing a colonic subsite. They were compared regarding demographic factors, tumor stage, metastatic spread and histopathological characteristics.

RESULTS

Analysis of tumor differentiation and histological subtype revealed a linear correlation to the ileocecal valve, supporting the right and left side classification model. However, cancers arising from the RCC's cecum (52.3%) and LCC's splenic flexure (51.0%) showed the highest proportion of UICC stage III/IV tumors and lymphatic invasion, whereas the RCC's ascending colon (46.5%) and LCC's descending (44.7%) showed the lowest, which supports a more complex classification system, breaking down the right and left sides into colonic subsites.

CONCLUSIONS

Age, tumor grade and histological subtype support the right and left side classification model. However, gender, UICC stage, metastatic spread, T and N status, and lymphatic invasion correlated with a specific colonic subsite, irrespective of the side. The classification of RCC or LCC provides a general understanding of the tumor, but identification of the colonic subsite provides additional prognostic information. This study shows that the standard right and left side classification model may be insufficient.

Wireless pH-motility capsule for colonic transit: prospective comparison with radiopaque markers in chronic constipation

BACKGROUND

Colon transit (CT) measurements are used in the management of significant constipation. The radiopaque marker (ROM) method provides limited information.

METHODS

We proposed to validate wireless motility capsule (WMC), that measures pH, pressure and temperature, to ROM measurement of CT in patients with symptomatic constipation evaluated at multiple centers. Of 208 patients recruited, 158 eligible patients underwent simultaneous measurement of colonic transit time (CTT) using ROM (Metcalf method, cut off for delay >67 h), and WMC (cutoff for delay >59 h). The study was designed to demonstrate substantial equivalence, defined as diagnostic agreement >65% for patients who had normal or delayed ROM transit.

KEY RESULTS

Fifty-nine of 157 patients had delayed ROM CT. Transit results by the two methods differed: ROM median 55.0 h [IQR 31.0-85.0] and WMC (43.5 h [21.7-70.3], P < 0.001. The positive percent agreement between WMC and ROM for delayed transit was approximately 80%; positive agreement in 47 by WMC/59 by ROM or 0.796 (95% CI = 0.67-0.98); agreement vs null hypothesis (65%) P = 0.01. The negative percent agreement (normal transit) was approximately 91%: 89 by WMC/98 by ROM or 0.908 (95% CI = 0.83-0.96); agreement vs null hypothesis (65%), P = 0.00001. Overall device agreement was 87%. There were significant correlations (P < 0.001) between ROM and WMC transit (CTT [r = 0.707] and between ROM and combined small and large bowel transit [r = 0.704]). There were no significant adverse events.

CONCLUSIONS & INFERENCES

The 87% overall agreement (positive and negative) validates WMC relative to ROM in differentiating slow vs normal CT in a multicenter clinical study of constipation.