Glucagon-like Peptide-1 Agonist Liraglutide Induces Temporary Impairment to Gastric Electrical Activity in Healthy Volunteers.

Body Surface Gastric Mapping to Determine Patterns of Gastric Electrical Activity Associated with Delayed Gastric Emptying after Pancreaticoduodenectomy (GEMAP Study)

High-resolution electrogastrography (HR-EGG) presents a new paradigm in diagnosing and treating functional gastroduodenal disorders. Unlike traditional electrogastrography, HR-EGG allows for a more precise analysis of the gastric electrical activity, offering improved diagnostic accuracy. Recent studies have revealed the clinical potential of HR-EGG, particularly in detecting abnormal electrical patterns in patients with functional dyspepsia and gastroparesis, supporting the development of novel therapeutic strategies. The non-invasive HR-EGG method has shown promise in identifying new biomarkers. Moreover, further integration of artificial intelligence, is expected to enhance diagnostic efficiency and develop more refined treatment models for functional gastrointestinal disorders.

Biopsychosocial factors are associated with disorders of gut-brain interaction (DGBI) and exacerbate gastrointestinal symptoms. The mechanisms underlying pathophysiological alterations of stress remain unclear. Corticotropin-releasing hormone (CRH) is a central regulator of the hormonal stress response and has diverse impact on different organ systems. The aim of the present study was to investigate the effects of peripheral CRH infusion on meal-related gastrointestinal symptoms, gastric electrical activity, and gastric sensorimotor function in healthy volunteers (HVs). In a randomized, double-blinded, placebo-controlled, crossover study, we evaluated the effects of CRH on gastric motility and sensitivity. HVs were randomized to receive either peripheral-administered CRH (100 µg bolus + 1 µg/kg/h) or placebo (saline), followed by at least a 7-day washout period and assignment to the opposite treatment. Tests encompassed saliva samples, gastric-emptying (GE) testing, body surface gastric mapping (BSGM, Gastric Alimetry; Alimetry) to assess gastric myoelectrical activity with real-time symptom profiling, and a gastric barostat study to assess gastric sensitivity to distention and accommodation. Twenty HVs [13 women, mean age 29.2 ± 5.3 yr, body mass index (BMI) 23.3 ± 3.8 kg/m2] completed GE tests, of which 18 also underwent BSGM measurements during the GE tests. The GE half-time decreased significantly after CRH exposure (65.2 ± 17.4 vs. 78.8 ± 24.5 min, P = 0.02) with significantly increased gastric amplitude [49.7 (34.7-55.6) vs. 31.7 (25.7-51.0) µV, P < 0.01], saliva cortisol levels, and postprandial symptom severity. Eleven HVs also underwent gastric barostat studies on a separate day. However, the thresholds for discomfort during isobaric distensions, gastric compliance, and accommodation did not differ between CRH and placebo.NEW & NOTEWORTHY In healthy volunteers, peripheral corticotropin-releasing hormone (CRH) infusion accelerates gastric-emptying rate and increases postprandial gastric response, accompanied by a rise in symptoms, but does not alter gastric sensitivity or meal-induced accommodation. These findings underscore a significant link between stress and dyspeptic symptoms, with CRH playing a pivotal role in mediating these effects.

Artificial intelligence (AI) is a broad term that pertains to a computer's ability to mimic and sometimes surpass human intelligence in interpretation of large datasets. The adoption of AI in gastrointestinal motility has been slower compared to other areas such as polyp detection and interpretation of histopathology. Within esophageal physiologic testing, AI can automate interpretation of image-based tests, especially high resolution manometry (HRM) and functional luminal imaging probe (FLIP) studies. Basic tasks such as identification of landmarks, determining adequacy of the HRM study and identification from achalasia from non-achalasia patterns are achieved with good accuracy. However, existing AI systems compare AI interpretation to expert analysis rather than to clinical outcome from management based on AI diagnosis. The use of AI methods is much less advanced within the field of ambulatory reflux monitoring, where challenges exist in assimilation of data from multiple impedance and pH channels. There remains potential for replication of the AI successes within esophageal physiologic testing to HRM of the anorectum, and to innovative and novel methods of evaluating gastric electrical activity and motor function. The use of AI has tremendous potential to improve detection of dysmotility within the esophagus using esophageal physiologic testing, as well as in other regions of the gastrointestinal tract. Eventually, integration of patient presentation, demographics and alternate test results to individual motility test interpretation will improve diagnostic precision and prognostication using AI tools.

Body surface gastric mapping to determine patterns of gastric electrical activity associated with delayed gastric emptying after pancreaticoduodenectomy: study protocol and preliminary results of the gemap study

Despite evidence that slow-wave dysrhythmia in the stomach is associated with clinical conditions such as gastroparesis and functional dyspepsia, there is still no widely available device for long-term monitoring of gastric electrical signals. Actionable biomarkers of gastrointestinal health are critically needed, and an implantable slow-wave monitoring device could aid in the establishment of causal relationships between symptoms and gastric electrophysiology. Recent developments in the area of wireless implantable gastric monitors demonstrate potential, but additional work and validation are required before this potential can be realized. We hypothesized that translating an existing implantable cardiac monitoring device, the Reveal LINQ™ (Medtronic), would present a more immediate solution. Following ethical approval and laparotomy in anesthetized pigs (n = 7), a Reveal LINQ was placed on the serosal surface of the stomach, immediately adjacent to a validated flexible-printed-circuit (FPC) electrical mapping array. Data were recorded for periods of 7.5 min, and the resultant signal characteristics from the FPC array and Reveal LINQ were compared. The Reveal LINQ device recorded slow waves in 6/7 subjects with a comparable period (p = 0.69), signal-to-noise ratio (p = 0.58), and downstroke width (p = 0.98) to the FPC, but with reduced amplitude (p = 0.024). Qualitatively, the Reveal LINQ slow-wave signal lacked the prolonged repolarization phase present in the FPC signals. These findings suggest that existing cardiac monitors may offer an efficient solution for the long-term monitoring of slow waves. Translation toward implantation now awaits.

Vagus nerve stimulation (VNS) is a potential treatment option for gastrointestinal (GI) diseases. The present study aimed to understand the physiological effects of VNS on gastrointestinal (GI) function, which is crucial for developing more effective adaptive closed-loop VNS therapies for GI diseases. Electrogastrography (EGG), which measures gastric electrical activities (GEAs) as a proxy to quantify GI functions, was employed in our investigation. We introduced a recording schema that allowed us to simultaneously induce electrical VNS and record EGG. While this setup created a unique model for studying the effects of VNS on the GI function and provided an excellent testbed for designing advanced neuromodulation therapies, the resulting data was noisy, heterogeneous, and required specialized analysis tools. The current study aimed at formulating a systematic and interpretable approach to quantify the physiological effects of electrical VNS on GEAs in ferrets by using signal processing and machine learning techniques. Our analysis pipeline included pre-processing steps, feature extraction from both time and frequency domains, a voting algorithm for selecting features, and model training and validation. Our results indicated that the electrophysiological changes induced by VNS were optimally characterized by a distinct set of features for each classification scenario. Additionally, our findings demonstrated that the process of feature selection enhanced classification performance and facilitated representation learning.

Background. Electrogastrography and electroenterography are noninvasive methods for measuring gastric and intestinal electrical activities, respectively. Few studies have measured electroenterography in healthy humans; however, no studies have measured electrogastrography and electroenterography simultaneously. This study was performed to provide basic electrogastrography and electroenterography data for comparison with future studies in patients. Methods. Simultaneous preprandial and postprandial measurements of electrogastrography and electroenterography were taken for 30 min each in 50 healthy volunteers. Power spectrum analysis was performed to calculate dominant frequency, dominant power, and power ratio. Results. Gastric and small intestinal dominant frequencies were not significantly different between preprandial and postprandial periods. In preprandial and postprandial periods, normogastria was seen in 49 (98%) and 44 (88%) patients ( p = 0.063 ), bradygastria in 1 (2%) and 6 (12%) patients ( p = 0.063 ), and tachygastria in 0 (0%) patients, respectively. Dominant power was significantly increased in the stomach (828 [460–3203] μV2 vs. 1526 [759–2958] μV2, p = 0.016 ) and small intestine (49 [27–86] μV2 vs. 68 [37–130] μV2, p &lt; 0.001 ). The power ratio was 1.6 (0.9–2.5) in the stomach and 1.4 (1.0–2.5) in the small intestine. Body mass index showed a negative correlation with the stomach and small intestinal dominant power in preprandial and postprandial periods ( r s = − 0.566 , p &lt; 0.001 ; r s = − 0.534 , p &lt; 0.001 ; r s = − 0.459 , p &lt; 0.001 ; and r s = − 0.529 , p &lt; 0.001 , respectively). The Bristol Stool Form Scale correlated positively with the small intestinal power ratio ( r s = − 0.430 , p = 0.002 ). Conclusion. There was no change in frequency in the stomach or small intestine, but power significantly increased in both the stomach and small intestine.

Characterization of rat gastric myogenic contractions and modulation by oxytocin and arginine-vasopressin

The management strategy for patients with an overlap between functional dyspepsia and irritable bowel syndrome remains insufficiently explored. Objective. Yo assess the severity of functional dyspepsia (FD) symptoms with concomitant irritable bowel syndrome (IBS) and Helicobacter pylori (H. pylori) infection. Methods and materials. We examined 27 patients with IBS who were being treated at the Gastroenterology Center. We used surveys: «7×7», the Spielberger-Hanin anxiety test, and a survey of the attitude toward the diseases. Additionally, we conducted peripheral electrogastroenterocolography and H. pylori detection using serology, rapid urease tests, or stool antigen tests. Results. We found that 44.4% of patients had overlap between FD and IBS. According to the «7×7» questionnaire, patients with both conditions reported a high level of distress, scoring 20 [15.25; 21.75] points. In contrast, those with only IBS had milder distress, scoring 11 [10; 13] points (p&lt;0.001). Individuals with H.pylori infection reported even higher distress levels, scoring 21 [12; 22] points, while those without the infection reported moderate distress, with a score of 13 [10; 14.75] points (p=0.036). Among patients with H. pylori infection, 85.7% experienced FD symptoms, compared to 30% in patients without H. pylori infection (p=0.024). The amplitude of gastric electrical activity, gastric and duodenal rhythms in patients with both IBS and FD was greater than in patients with only IBS (p=0.03). Most patients with isolated IBS and those with both IBS and FD had a high level of anxiety (74.1%) but had a positive attitude towards their illness (63%). Conclusion. Overlap between IBS and FD worsens the overall well-being of patients. H. pylori infection may play a role in exacerbating gastrointestinal symptoms in patients with functional diseases.

The impact of ineffective esophageal motility (IEM) on gastroesophageal reflux disease (GERD) remains unknown, and abnormal esophageal motility often coexists with abnormal gastric motility. We aimed to investigate the role of IEM in GERD and its relationship with gastric electrical activity. Patients diagnosed as GERD based on GERD-questionnaire score ≥8 in our hospital from January 2020 to June 2022 were included. All patients underwent 24-h multichannel intraluminal impedance-pH monitoring, high-resolution manometry, and electrogastrogram and were categorized into the normal esophageal motility (NEM) and IEM groups, respectively. Reflux characteristics and gastric electric activity were compared between the two groups, and the correlation between gastric electric activity and reflux was analyzed. Acid exposure time, total reflux episodes, and DeMeester score in the IEM group were higher than those in the NEM group. Distal mean nocturnal baseline impedance was significantly lower in the IEM group. Compared with the NEM group, the power ratio (PR) of fundus, antrum and pylorus and premeal and postmeal normal wave ratio of antrum were significantly lower in IEM. The total reflux episodes were negatively correlated with the PR of fundus and pylorus, and the DeMeester score was negatively correlated with the PR of corpus and pylorus. IEM may lead to increased reflux, resulting in esophageal mucosal damage. There may be consistency between abnormal esophageal motility and gastric motility.

The motility patterns in the gastrointestinal tract are regulated, in part, by bioelectrical events known as slow waves (SWs). Understanding temporal and spatial features of gastric SWs can help reveal the underlying causes of functional motility disorders. This study investigated the ability of source localization techniques to characterize the spatial signatures of SW activity using simulated and experimental magnetogastrography data. Two SW propagation patterns (antegrade and retrograde) with two rhythms (normogastric and bradygastric) were used to simulate magnetic fields using 4 anatomically realistic stomach and torso geometries. Source localization was performed utilizing the equivalent current dipole (ECD) and the equivalent magnetic dipole (EMD) models. In the normogastric simulations when compared with the SW activity, the EMD model was capable of identifying the SW propagation in the lateral, antero-posterior, and supero-inferior axes with the median correlation coefficients of 0.66, 0.53, and 0.83, respectively, whereas the ECD model produced lower correlation scores (median: 0.52, 0.44, and 0.44). Moreover, the EMD model resulted in distinct and opposite spatial signatures for the antegrade and retrograde propagation. Similarly, when experimental data was used, the EMD model revealed antegrade-like signatures where the propagation was mostly towards the third quadrant in the supero-inferior (preprandial: 49%, postprandial: 35%) and antero-posterior (preprandial: 49%, postprandial: 50%) axes. The EMD model was able to identify and classify the spatial signatures of SW activities, which can help to inform the interpretation of non-invasive recordings of gastric SWs as a biomarker of functional motility disorders.

Gastric pacing is an attractive therapeutic approach for correcting abnormal bioelectrical activity. While high-resolution (HR) electrical mapping techniques have largely contributed to the current understanding of the effect of pacing on the electrophysiological function, these mapping techniques are restricted to surface contact electrodes and the signal quality can be corrupted by pacing artifacts. Optical mapping of voltage sensitive dyes is an alternative approach used in cardiac research, and the signal quality is not affected by pacing artifacts. In this study, we simultaneously applied HR optical and electrical mapping techniques to evaluate the bioelectrical slow wave response to gastric pacing. The studies were conducted in vivo on porcine stomachs ( n=3) where the gastric electrical activity was entrained using high-energy pacing. The pacing response was optically tracked using voltage-sensitive fluorescent dyes and electrically tracked using surface contact electrodes positioned on adjacent regions. Slow waves were captured optically and electrically and were concordant in time and direction of propagation with comparable mean velocities ([Formula: see text]) and periods ([Formula: see text]). Importantly, the optical signals were free from pacing artifacts otherwise induced in electrical recordings highlighting an advantage of optical mapping. Clinical Relevance- Entrainment mapping of gastric pacing using optical techniques is a major advance for improving the preclinical understanding of the therapy. The findings can thereby inform the efficacy of gastric pacing in treating functional motility disorders.

Gastrointestinal (GI) motility disorders in type 2 diabetes mellitus (T2DM) are common. However, the endpoints in well-controlled T2DM in elderly patients are barely understood. To evaluate GI transit and gastric myoelectric activity in elderly patients with T2DM who were undergoing treatment with metformin and to compare them with non-diabetic healthy controls. A total of thirty participants were enrolled in this study: young non-diabetic (n=10), elderly non-diabetic controls (n=10), and patients with T2DM managed with metformin (n=10). After fasting overnight, the participants ingested a standard meal and magnetic markers for non-invasive monitoring of GI transit and gastric contractility using the alternating current biosusceptometry and electrogastrography techniques. Mean gastric emptying time, mean colon arrival time, and mean intestinal transit time were determined. There were no significant differences between the groups and in the parameters evaluated (P>0.05). The frequency and amplitude of gastric myoelectric activity were not different between groups; however, abnormal rhythmic index and the half-bandwidth were slightly higher for both elderly diabetic and non-diabetic groups compared with the young adults (P<0.01 and P<0.05, respectively). Our study showed unaltered gastric emptying and intestinal transit in T2DM patients with good glycemic control, and suggest changes in the gastric electrical activity can be a part of aging.

The paper presents the results of the study aimed to evaluate whether prolonged consumption of a probiotic drink consisting of protective microorganisms (lactobacilli, enterococci, bifidobacteria) and fermented from Saccaromyces would be beneficial to the human microbiological status and gastrointestinal tract (GIT) functioning. Ten volunteers (2 males and 8 females above 50 years of age) consumed the drink over the period of three months. We investigated microflora of the intestine, upper airway (UA) and vagina (in females). Microbial samples from the intestine and UA were gathered 4 times: a week prior to the experiment and then in every 30 days. Samples of the vaginal discharge were taken 7-10 days prior to the experiment and in 7–10 after its completion. Evaluation of the gastric emptying function, hydrochloric acid production, fasting volume of the gastric juice and GIT electrical activity was performed at these time points also. The experiment revealed positive trends of the intestinal microflora. Changes in the species and quantitative composition of the UA microflora were less pronounced as in the first half of the experiment changes in the UA microflora were more like negative and displayed a marked positive trend in the second half. After the course of probiotic prophylaxis, colonization of the vagina and cervical channel by opportunistic microorganisms was reduced in 6 out of 8 females. In addition, the probiotic drink stabilized the electrical activity of all GIT components and enhanced intestinal peristalsis.

Gastric Electrical Response Activity Assessment Method with Simple Multi Channel Electrogastrography

Gastroparesis is a chronic stomach disorder and effective treatment is the aim of different strategies. Alternative therapies consist of an electrical stimulation of the stomach to evoke a response in the gastric activity. We present the development and in vivo application of an electromagnet system to induce a mechanical stimulus in the stomach aiming for gastric contractile responses. The electromagnet system consisted of an implantable magnet and an external drive coil. We implanted the magnet at the greater curvature of the gastric body in rats. We applied an alternating current to the drive coils, inducing mechanical stimulation of the gastric wall. We measured the gastric contraction activity and gastric electrical activity in response to the stimulus using AC biosusceptometry and electrogastrography. Moreover, we used the phenol red to evaluate the stimulus effects on gastrointestinal transit. The stimulus increased the spectral intensity and signal-to-noise ratio significantly of gastric contraction activity and gastric electrical activity. Furthermore, we found a lower phenol red retention in the stomach in rats without stimulus. No significant differences were found in frequency and root mean square amplitude. We developed a new simple electromagnet system that evoked a contraction and gastric electrical response using a mechanical stimulus and decreased gastric emptying time. The system is an accessible tool and may contribute to gastroparesis studies in animals.

Functional dyspepsia (FD) is a common gastroduodenal disorder, yet its pathophysiology remains poorly understood. Bioelectrical gastric slow-wave abnormalities are thought to contribute to its multifactorial pathophysiology. Electrogastrography (EGG) has been used to record gastric electrical activity; however, the clinical associations require further evaluation. This study aimed to systematically assess the clinical associations of EGG in FD. MEDLINE, EMBASE, and CENTRAL databases were systematically searched for articles using EGG in adults with FD. Primary outcomes were percentage normal versus abnormal rhythm (bradygastria, normogastria, and tachygastria). Secondary outcomes were dominant power, dominant frequency, percentage coupling, and the meal responses. 1751 FD patients and 555 controls from 47 studies were included. FD patients spent less time in normogastria while fasted (SMD -0.74; 95%CI -1.22 to -0.25) and postprandially (-0.86; 95%CI -1.35 to -0.37) compared with controls. FD patients also spent more fasted time in bradygastria (0.63; 95%CI 0.33-0.93) and tachygastria (0.45; 95%CI 0.12-0.78%). The power ratio (-0.17; 95%CI -0.83-0.48) and dominant frequency meal-response ratio (0.06; 95%CI -0.08-0.21) were not significantly different to controls. Correlations between EGG metrics and the presence and timing of FD symptoms were inconsistent. EGG methodologies were diverse and variably applied. Abnormal gastric slow-wave rhythms are a consistent abnormality present in FD, as defined by EGG and, therefore, likely play a role in pathophysiology. The aberrant electrophysiology identified in FD warrants further investigation, including into underlying mechanisms, associated spatial patterns, and symptom correlations.

Electrogastrography for diagnosis of early-stage Parkinson's disease