Rhythmic and spatial abnormalities of gastric slow waves in patients with functional dyspepsia

Vectorgastrogram: dynamic trajectory and recurrence quantification analysis to assess slow wave vector movement in healthy subjects

Functional gastric disorders entail chronic or recurrent symptoms, high prevalence and a significant financial burden. These disorders do not always involve structural abnormalities and since they cannot be diagnosed by routine procedures, electrogastrography (EGG) has been proposed as a diagnostic alternative. However, the method still has not been transferred to clinical practice due to the difficulty of identifying gastric activity because of the low-frequency interference caused by skin-electrode contact potential in obtaining spatiotemporal information by simple procedures. This work attempted to robustly identify the gastric slow wave (SW) main components by applying multivariate variational mode decomposition (MVMD) to the multichannel EGG. Another aim was to obtain the 2D SW vectorgastrogram VGGSW from 4 electrodes perpendicularly arranged in a T-shape and analyse its dynamic trajectory and recurrence quantification (RQA) to assess slow wave vector movement in healthy subjects. The results revealed that MVMD can reliably identify the gastric SW, with detection rates over 91% in fasting postprandial subjects and a frequency instability of less than 5.3%, statistically increasing its amplitude and frequency after ingestion. The VGGSW dynamic trajectory showed a statistically higher predominance of vertical displacement after ingestion. RQA metrics (recurrence ratio, average length, entropy, and trapping time) showed a postprandial statistical increase, suggesting that gastric SW became more intense and coordinated with a less complex VGGSW and higher periodicity. The results support the VGGSW as a simple technique that can provide relevant information on the "global" spatial pattern of gastric slow wave propagation that could help diagnose gastric pathologies.

Children and Adolescents with Irritable Bowel Syndrome: Treatment and Management

BACKGROUND

Irritable bowel syndrome (IBS) is a disorder that causes stomach pain in children and adolescents. It may also impact one's quality of life. IBS is linked to gastrointestinal issues such as diarrhoea and constipation. Despite the identification of several potential pathophysiological pathways, the aetiology of IBS remained unknown.

OBJECTIVE

The aim of this paper is to discuss the diagnosis, pathogenesis, case studies and treatment of Irritable bowel syndrome in children and adolescents.

METHODS

This systematic review covered relevant papers from the previous ten years that were accessible in Science Direct, Elsevier, NCBI, and Web of Science related to the pathophysiology and function of pharmacological drugs such as antidepressants, antispasmodics, prokinetics, and antibiotics in children with irritable bowel syndrome.

RESULTS

Only a few prospective therapy techniques have been investigated in children, and even fewer of those have been demonstrated to be effective. This article presents case studies including 50-59 children, which demonstrate a favourable acceptable impact that is more effective than a placebo in terms of reducing symptoms and improving the overall quality of life in children who have irritable bowel syndrome. Furthermore, the majority of the pathophysiological explanations and treatment options discussed are based on adult studies. These major issues arose when treating paediatric IBS, and they must be addressed in order to properly treat children with IBS. Trials that focus on many combinations of pharmacological and non-pharmacological therapies seem to be more helpful.

DISCUSSION

In recent years, a number of systematic reviews have been conducted to evaluate the efficacy of medication treatments in children for IBS; however, the dependability of these systematic reviews needs to be further investigated owing to the various experimental designs and levels of evidence used. This article highlights paediatric therapy options, including pharmaceutical medications such as antidepressants, antispasmodics, prokinetics, and antibiotics. The goal is to alleviate IBS symptoms while also enhancing the quality of life for children with this illness.

Optimization of Gastric Pacing Parameters Using High-Resolution Mapping

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The regulatory effects of fucoidan and laminarin on functional dyspepsia mice induced by loperamide

Gastrointestinal dysmotility is a common cause of functional dyspepsia. As two kinds of polysaccharides derived from brown algae, fucoidan and laminarin possess many physiological properties; however, their relative abilities in regulating gastrointestinal motility have not been illustrated yet. In this study, we aimed to investigate the regulatory effect of fucoidan and laminarin on functional dyspepsia mice induced by loperamide. Mice with gastrointestinal dysmotility were treated with fucoidan (100 and 200 mg per kg bw) and laminarin (50 and 100 mg per kg bw). As a result, fucoidan and laminarin reversed the dysfunction mainly through regulating gastrointestinal hormones (motilin and ghrelin), the cholinergic pathway, the total bile acid level, c-kit protein expression, and gastric smooth muscle contraction-related gene expression (ANO1 and RYR3). Moreover, fucoidan and laminarin intervention modulated the gut microbiota profile including the altered richness of Muribaculaceae, Lachnospiraceae, and Streptococcus. The results indicated that fucoidan and laminarin may restore the rhythm of the migrating motor complex and regulate gut microecology. In conclusion, we provided evidence to support that fucoidan and laminarin might have potential abilities to regulate gastrointestinal motility.

Localized bioelectrical conduction block from radiofrequency gastric ablation persists after healing: safety and feasibility in a recovery model

Gastric ablation has demonstrated potential to induce conduction blocks and correct abnormal electrical activity (i.e., ectopic slow-wave propagation) in acute, intraoperative in vivo studies. This study aimed to evaluate the safety and feasibility of gastric ablation to modulate slow-wave conduction after 2 wk of healing. Chronic in vivo experiments were performed in weaner pigs (n = 6). Animals were randomly divided into two groups: sham-ablation (n = 3, control group; no power delivery, room temperature, 5 s/point) and radiofrequency (RF) ablation (n = 3; temperature-control mode, 65°C, 5 s/point). In the initial surgery, high-resolution serosal electrical mapping (16 × 16 electrodes; 6 × 6 cm) was performed to define the baseline slow-wave activation profile. Ablation (sham/RF) was then performed in the mid-corpus, in a line around the circumferential axis of the stomach, followed by acute postablation mapping. All animals recovered from the procedure, with no sign of perforation or other complications. Two weeks later, intraoperative high-resolution mapping was repeated. High-resolution mapping showed that ablation successfully induced sustained conduction blocks in all cases in the RF-ablation group at both the acute and 2 wk time points, whereas all sham-controls had no conduction block. Histological and immunohistochemical evaluation showed that after 2 wk of healing, the lesions were in the inflammation and early proliferation phase, and interstitial cells of Cajal (ICC) were depleted and/or deformed within the ablation lesions. This safety and feasibility study demonstrates that gastric ablation can safely and effectively induce a sustained localized conduction block in the stomach without disrupting the surrounding slow-wave conduction capability.NEW & NOTEWORTHY Ablation has recently emerged as a tool for modulating gastric electrical activation and may hold interventional potential for disorders of gastric function. However, previous studies have been limited to the acute intraoperative setting. This study now presents the safety of gastric ablation after postsurgical recovery and healing. Localized electrical conduction blocks created by ablation remained after 2 wk of healing, and no perforation or other complications were observed over the postsurgical period.

Non-pharmacological management of pediatric functional abdominal pain disorders: Current evidence and future perspectives

Functional abdominal pain disorders (FAPDs) are an important and prevalent cause of functional gastrointestinal disorders among children, encompassing the diagnoses of functional dyspepsia, irritable bowel syndrome, abdominal migraine, and the one not previously present in Rome III, functional abdominal pain not otherwise specified. In the absence of sufficiently effective and safe pharmacological treatments for this public problem, non-pharmacological therapies emerge as a viable means of treating these patients, avoiding not only possible side effects, but also unnecessary prescription, since many of the pharmacological treatments prescribed do not have good efficacy when compared to placebo. Thus, the present study provides a review of current and relevant evidence on non-pharmacological management of FAPDs, covering the most commonly indicated treatments, from cognitive behavioral therapy to meditation, acupuncture, yoga, massage, spinal manipulation, moxibustion, and physical activities. In addition, this article also analyzes the quality of publications in the area, assessing whether it is possible to state if non-pharmacological therapies are viable, safe, and sufficiently well-based for an appropriate and effective prescription of these treatments. Finally, it is possible to observe an increase not only in the number of publications on the non-pharmacological treatments for FAPDs in recent years, but also an increase in the quality of these publications. Finally, the sample selection of satisfactory age groups in these studies enables the formulation of specific guidelines for this age group, thus avoiding the need for adaptation of prescriptions initially made for adults, but for children use.

Biosensor-Assisted Method for Abdominal Syndrome Classification Using Machine Learning Algorithm

The digestive system is one of the essential systems in human physiology where the stomach has a significant part to play with its accessories like the esophagus, duodenum, small intestines, and large intestinal tract. Many individuals across the globe suffer from gastric dysrhythmia in combination with dyspepsia (improper digestion), unexplained nausea (feeling), vomiting, abdominal discomfort, ulcer of the stomach, and gastroesophageal reflux illnesses. Some of the techniques used to identify anomalies include clinical analysis, endoscopy, electrogastrogram, and imaging. Electrogastrogram is the registration of electrical impulses that pass through the stomach muscles and regulate the contraction of the muscle. The electrode senses the electrical impulses from the stomach muscles, and the electrogastrogram is recorded. A computer analyzes the captured electrogastrogram (EGG) signals. The usual electric rhythm produces an enhanced current in the typical stomach muscle after a meal. Postmeal electrical rhythm is abnormal in those with stomach muscles or nerve anomalies. This study considers EGG of ordinary individuals, bradycardia, dyspepsia, nausea, tachycardia, ulcer, and vomiting for analysis. Data are collected in collaboration with the doctor for preprandial and postprandial conditions for people with diseases and everyday individuals. In CWT with a genetic algorithm, db4 is utilized to obtain an EGG signal wave pattern in a 3D plot using MATLAB. The figure shows that the existence of the peak reflects the EGG signal cycle. The number of present peaks categorizes EGG. Adaptive Resonance Classifier Network (ARCN) is utilized to identify EGG signals as normal or abnormal subjects, depending on the parameter of alertness (μ). This study may be used as a medical tool to diagnose digestive system problems before proposing invasive treatments. Accuracy of the proposed work comes up with 95.45%, and sensitivity and specificity range is added as 92.45% and 87.12%.

Electrogastrography Abnormalities in Pediatric Gastroduodenal Disorders: A Systematic Review and Meta-analysis

Electrogastrography (EGG) is a non-invasive method of measuring gastric electrophysiology. Abnormal gastric electrophysiology is thought to contribute to disease pathophysiology in patients with gastroduodenal symptoms but this has not been comprehensively quantified in pediatric populations. This study aimed to quantify the abnormalities in gastric electrophysiology on EGG in neonatal and pediatric patients.Databases were systematically searched for articles utilizing EGG in neonatal and pediatric patients (≤18 years). Primary outcomes were prevalence of abnormality, percentage of time in normal rhythm, and power ratio. Secondary outcomes were correlations between patient symptoms and abnormal gastric electrophysiology on EGG.A total of 33 articles (1444 participants) were included. EGG methodologies were variable. Pooled prevalence of abnormalities on EGG ranged from 61% to 86% in patients with functional dyspepsia (FD), gastro-esophageal reflux disease (GERD), and type 1 diabetes mellitus (T1DM). FD patients averaged 20.8% (P = 0.011) less preprandial and 21.6% (P = 0.031) less postprandial time in normogastria compared with controls. Electrophysiological abnormalities were inconsistent in GERD. T1DM patients averaged 46.2% (P = 0.0003) less preprandial and similar (P = 0.32) postprandial time in normogastria compared with controls, and had a lower power ratio (SMD -2.20, 95% confidence interval [CI]: -4.25 to -0.15; P = 0.036). Symptom correlations with gastric electrophysiology were inconsistently reported.Abnormalities in gastric electrophysiology were identifiable across a range of pediatric patients with gastroduodenal symptoms on meta-analysis. However, techniques have been inconsistent, and standardized and more reliable EGG methods are desirable to further define these findings and their potential utility in clinical practice.

Transcutaneous auricular vagal nerve stimulation improves functional dyspepsia by enhancing vagal efferent activity

This study was designed to investigate whether transcutaneous auricular vagal nerve stimulation (taVNS) would be able to improve major pathophysiologies of functional dyspepsia (FD) in patients with FD. Thirty-six patients with FD (21 F) were studied in two sessions (taVNS and sham-ES). Physiological measurements, including gastric slow waves, gastric accommodation, and autonomic functions, were assessed by the electrogastrogram (EGG), a nutrient drink test and the spectral analysis of heart rate variability derived from the electrocardiogram (ECG), respectively. Thirty-six patients with FD (25 F) were randomized to receive 2-wk taVNS or sham-ES. The dyspeptic symptom scales, anxiety and depression scores, and the same physiological measurements were assessed at the beginning and the end of the 2-wk treatment. In comparison with sham-ES, acute taVNS improved gastric accommodation (P = 0.008), increased the percentage of normal gastric slow waves (%NSW, fasting: P = 0.010; fed: P = 0.007) and vagal activity (fasting: P = 0.056; fed: P = 0.026). In comparison with baseline, 2-wk taVNS but not sham-ES reduced symptoms of dyspepsia (P = 0.010), decreased the scores of anxiety (P = 0.002) and depression (P < 0.001), and improved gastric accommodation (P < 0.001) and the %NSW (fasting: P < 0.05; fed: P < 0.05) by enhancing vagal efferent activity (fasting: P = 0.015; fed: P = 0.048). Compared with the HC, the patients showed increased anxiety (P < 0.001) and depression (P < 0.001), and decreased gastric accommodation (P < 0.001) and %NSW (P < 0.001) as well as decreased vagal activity (fasting: P = 0.047). The noninvasive taVNS has a therapeutic potential for treating nonsevere FD by improving gastric accommodation and gastric pace-making activity via enhancing vagal activity.NEW & NOTEWORTHY Treatment of functional dyspepsia is difficult due to various pathophysiological factors. The proposed method of transcutaneous auricular vagal nerve stimulation improves symptoms of both dyspepsia and depression/anxiety, and gastric functions (accommodation and slow waves), possibly mediated via the enhancement of vagal efferent activity. This noninvasive and easy-to-implement neuromodulation method will be well received by patients and healthcare providers.

Strategies to Refine Gastric Stimulation and Pacing Protocols: Experimental and Modeling Approaches

Gastric pacing and stimulation strategies were first proposed in the 1960s to treat motility disorders. However, there has been relatively limited clinical translation of these techniques. Experimental investigations have been critical in advancing our understanding of the control mechanisms that innervate gut function. In this review, we will discuss the use of pacing to modulate the rhythmic slow wave conduction patterns generated by interstitial cells of Cajal in the gastric musculature. In addition, the use of gastric high-frequency stimulation methods that target nerves in the stomach to either inhibit or enhance stomach function will be discussed. Pacing and stimulation protocols to modulate gastric activity, effective parameters and limitations in the existing studies are summarized. Mathematical models are useful to understand complex and dynamic systems. A review of existing mathematical models and techniques that aim to help refine pacing and stimulation protocols are provided. Finally, some future directions and challenges that should be investigated are discussed.

Body surface mapping of the stomach: New directions for clinically evaluating gastric electrical activity

BACKGROUND

Gastric motility disorders, which include both functional and organic etiologies, are highly prevalent. However, there remains a critical lack of objective biomarkers to guide efficient diagnostics and personalized therapies. Bioelectrical activity plays a fundamental role in coordinating gastric function and has been investigated as a contributing mechanism to gastric dysmotility and sensory dysfunction for a century. However, conventional electrogastrography (EGG) has not achieved common clinical adoption due to its perceived limited diagnostic capability and inability to impact clinical care. The last decade has seen the emergence of novel high-resolution methods for invasively mapping human gastric electrical activity in health and disease, providing important new insights into gastric physiology. The limitations of EGG have also now become clearer, including the finding that slow-wave frequency alone is not a reliable discriminator of gastric dysrhythmia, shifting focus instead toward altered spatial patterns. Recently, advances in bioinstrumentation, signal processing, and computational modeling have aligned to allow non-invasive body surface mapping of the stomach to detect spatiotemporal gastric dysrhythmias. The clinical relevance of this emerging strategy to improve diagnostics now awaits determination.

PURPOSE

This review evaluates these recent advances in clinical gastric electrophysiology, together with promising emerging data suggesting that novel gastric electrical signatures recorded at the body surface (termed "body surface mapping") may correlate with symptoms. Further technological progress and validation data are now awaited to determine whether these advances will deliver on the promise of clinical gastric electrophysiology diagnostics.

Effects and mechanisms of acupuncture and electroacupuncture for functional dyspepsia: A systematic review

BACKGROUND

Functional dyspepsia (FD) is a common digestive disease with limited therapeutic options. According to evidence-based clinical practice, acupuncture or electroacupuncture (EA) seems to be a promising therapy for patients with FD. However, there is still a lack of systematic reviews that have analyzed current clinical trials for a better understanding of mechanisms involved in the ameliorating effect of acupuncture and EA on FD.

AIM

To evaluate the results and qualities of existing clinical evidence for researching the underlying mechanisms of acupuncture/EA in treating FD.

METHODS

A systematic search of the literature was performed to identify randomized controlled trials in which research on the mechanism of acupuncture or EA was conducted in FD patients. Databases searched included PubMed, EMBASE, Cochrane Library, and Web of Science. Data extraction and quality assessment were completed by two investigators independently and the results of quality evaluation were exported through Review Manager V5.3.

RESULTS

Eight studies were included in this review with a total of 17 items for detecting techniques for mechanistic research. Positive effects of acupuncture and EA were observed in regulating gastric motility, gastric accommodation, mental status, gastrointestinal hormones, and central and autonomic functions while improving dyspeptic symptoms and quality of life.

CONCLUSION

The key findings of this systematic review support the potential of acupuncture and EA in altering the heterogeneous pathophysiology in patients with FD. However, high-quality studies with well-planned designs are necessary to provide more credible evidence.

A Deep Convolutional Neural Network Approach to Classify Normal and Abnormal Gastric Slow Wave Initiation From the High Resolution Electrogastrogram

OBJECTIVE

Gastric slow wave abnormalities have been associated with gastric motility disorders. Invasive studies in humans have described normal and abnormal propagation of the slow wave. This study aims to disambiguate the abnormally functioning wave from one of normalcy using multi-electrode abdominal waveforms of the electrogastrogram (EGG).

METHODS

Human stomach and abdominal models are extracted from computed tomography scans. Normal and abnormal slow waves are simulated along stomach surfaces. Current dipoles at the stomachs surface are propagated to virtual electrodes on the abdomen with a forward model. We establish a deep convolutional neural network (CNN) framework to classify normal and abnormal slow waves from the multi-electrode waveforms. We investigate the effects of non-idealized measurements on performance, including shifted electrode array positioning, smaller array sizes, high body mass index (BMI), and low signal-to-noise ratio (SNR). We compare the performance of our deep CNN to a linear discriminant classifier using wave propagation spatial features.

RESULTS

A deep CNN framework demonstrated robust classification, with accuracy above 90% for all SNR above 0 dB, horizontal shifts within 3 cm, vertical shifts within 6 cm, and abdominal tissue depth within 6 cm. The linear discriminant classifier was much more vulnerable to SNR, electrode placement, and BMI.

CONCLUSION

This is the first study to attempt and, moreover, succeed in using a deep CNN to disambiguate normal and abnormal gastric slow wave patterns from high-resolution EGG data.

SIGNIFICANCE

These findings suggest that multi-electrode cutaneous abdominal recordings have the potential to serve as widely deployable clinical screening tools for gastrointestinal foregut disorders.

Herbal medicine Banha-sasim-tang for the treatment of functional dyspepsia protocol for a systematic review of randomized controlled trials

BACKGROUND

Functional dyspepsia (FD) has a high prevalence rate. The dyspeptic symptoms are not easily cured despite the availability of various conventional Western medical treatments. Banha-sasim-tang (BST) is a traditional herbal medicine that has long been used for treating FD.

METHODS

The following databases will be searched from inception to January 2019: Medline via PubMed, the Cochrane Central Register of Controlled Trials, EMBASE, Allied and Complementary Medicine Database, National Digital Science Library, Korean Medical Database (KoreaMed), Oriental Medicine Advanced Searching Integrated System, Korean Studies Information Service System, China National Knowledge Infrastructure Database, and Citation Information by Nii. Randomized controlled trials (RCTs) that used BST or herbs-added BST for treating FD will be included in the systematic review. Control groups in these RCTs will be the placebo, no-treatment, and conventional Western medicine groups. RCTs that compared BST and Western medicine combination therapy with the conventional Western medicine will also be included in the systematic review to investigate the synergistic effect of BST and Western medicine. Data extraction and evaluation of risk of bias will be performed by 2 independent investigators. The primary outcome will be the total clinical effective rate and secondary outcomes will include gastrointestinal symptom scale, visual analog scale, FD-related quality of life, electrogastrography, plasma motilin, dyspepsia-related symptom score, gastric emptying, and adverse events. RevMan version 5.3 will be used for data integration and analysis.

RESULTS

This systematic review will provide a high-quality integration of current evidence of BST for treating FD from several aspects including total clinical effective rate, dyspepsia-related symptoms, quality of life, and adverse events.

CONCLUSIONS

This systematic review will provide evidence of the effectiveness and safety of BST on FD.

ETHICS AND DISSEMINATION

Identifying information of the participants will not be revealed; hence, this protocol does not need ethical approval. The systematic review will be published in a peer-reviewed journal and disseminated electronically.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42019123285.

Irritable bowel syndrome in children: Current knowledge, challenges and opportunities

Irritable bowel syndrome (IBS) is a common and troublesome disorder in children with an increasing prevalence noted during the past two decades. It has a significant effect on the lives of affected children and their families and poses a significant burden on healthcare systems. Standard symptom-based criteria for diagnosis of pediatric IBS have changed several times during the past two decades and there are some differences in interpreting symptoms between different cultures. This has posed a problem when using them to diagnose IBS in clinical practice. A number of potential patho-physiological mechanisms have been described, but so far the exact underlying etiology of IBS is unclear. A few potential therapeutic modalities have been tested in children and only a small number of them have shown some benefit. In addition, most of the described patho-physiological mechanisms and treatment options are based on adult studies. These have surfaced as challenges when dealing with pediatric IBS and they need to be overcome for effective management of children with IBS. Recently suggested top-down and bottom-up models help integrating reported patho-physiological mechanisms and will provide an opportunity for better understanding of the diseases process. Treatment trials targeting single treatment modalities are unlikely to have clinically meaningful therapeutic effects on IBS with multiple integrating patho-physiologies. Trials focusing on multiple combined pharmacological and non-pharmacological therapies are likely to yield more benefit. In addition to treatment, in the future, attention should be paid for possible prevention strategies for IBS.

Functional abdominal pain disorders in children

Chronic abdominal pain is a common problem in pediatric practice. The majority of cases fulfill the Rome IV criteria for functional abdominal pain disorders (FAPDs). At times, these disorders may lead to rather serious repercussions. Area covered: We have attempted to cover current knowledge on epidemiology, pathophysiology, risk factors related to pathophysiology, clinical evaluation and management of children with FAPDs. Expert commentary: FAPDs are a worldwide problem with a pooled prevalence of 13.5%. There are a number of predisposing factors and pathophysiological mechanisms including stressful events, child maltreatment, visceral hypersensitivity, altered gastrointestinal motility and change in intestinal microbiota. It is possible that the environmental risk factors intricately interact with genes through epigenetic mechanisms to contribute to the pathophysiology. The diagnosis mainly depends on clinical evaluation. Commonly used pharmacological interventions do not play a major role in relieving symptoms. Centrally directed, nonpharmacological interventions such as hypnotherapy and cognitive behavioral therapy have shown both short and long term efficacy in relieving pain in children with FAPDs. However, these interventions are time consuming and need specially trained staff and therefore, not currently available at grass root level. Clinicians and researchers should join hands in searching for more pragmatic and effective therapeutic modalities to improve overall care of children with FAPDs.

Circulating motilin, ghrelin, and GLP-1 and their correlations with gastric slow waves in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) commonly complain upper gastrointestinal (GI) symptoms, especially anorexia. Hemodialysis (HD) has been noted to improve GI symptoms; however, the underlying mechanisms are unclear. This study was designed 1) to study effects of HD on GI symptoms and gastric slow waves; and 2) to investigate possible roles of ghrelin and glucagon-like peptide-1 (GLP-1): the study recruited 13 healthy controls, 20 CKD patients without HD (CKD group), and 18 CKD patients with HD (HD group). Dyspeptic symptoms, autonomic functions, gastric slow waves, and plasma level of ghrelin and GLP-1 were analyzed. First, the CKD patients with HD showed markedly lower scores of anorexia (0.6 ± 0.2 vs. 3.2 ± 0.4, P < 0.001) compared with patients without HD. Second, the CKD group but not HD group showed a significant reduction (25.6%) in the percentage of normal gastric slow waves, compared with controls. Third, the CKD group exhibited a significantly lower ghrelin level compared with the HD group (26.8 ± 0.9 vs. 34.1 ± 2.3 ng/l, P < 0.02) and a higher GLP-1 level (29.4 ± 2.8 vs. 20.0 ± 2.1 pmol/l, P < 0.05) compared with controls. Moreover, the percentage of normal slow waves was positively correlated with ghrelin (r = 0.385, P = 0.019) but negatively correlated with GLP-1 (r = -0.558, P < 0.001) in all CKD patients. Hemodialysis improves upper GI symptoms and gastric slow waves in CKD patients. An increase in ghrelin and a decrease in GLP-1 might be involved in the HD-induced improvement in gastric slow waves.

Time-Delay Mapping of High-Resolution Gastric Slow-Wave Activity

GOAL

Analytic monitoring of electrophysiological data has become an essential component of efficient and accurate clinical care. In the gastrointestinal (GI) field, recent advances in high-resolution (HR) mapping are now providing critical information about spatiotemporal profiles of slow-wave activity in normal and disease (dysrhythmic) states. The current approach to analyze GI HR electrophysiology data involves the identification of individual slow-wave events in the electrode array, followed by tracking and clustering of events to create a spatiotemporal map. This method is labor and computationally intensive and is not well suited for real-time clinical use or chronic monitoring.

METHODS

In this study, an automated novel technique to assess propagation patterns was developed. The method utilized time delays of the slow-wave signals which was computed through cross correlations to calculate velocity. Validation was performed with both synthetic and human and porcine experimental data.

RESULTS

The slow-wave profiles computed via the time-delay method compared closely with those computed using the traditional method (speed difference: 7.2% ± 2.6%; amplitude difference: 8.6% ± 3.5%, and negligible angle difference).

CONCLUSION

This novel method provides rapid and intuitive analysis and visualization of slow-wave activity.

SIGNIFICANCE

This techniques will find major applications in the clinical translation of acute and chronic HR electrical mapping for motility disorders, and act as a screening tool for detailed detection and tracking of individual propagating wavefronts, without the need for comprehensive standard event-detection analysis.

Ameliorating effect of transcutaneous electroacupuncture on impaired gastric accommodation induced by cold meal in healthy subjects

BACKGROUND

Impaired gastric accommodation is recognized as one of major pathophysiologies in functional dyspepsia and gastroparesis. Electroacupuncture has been shown to improve gastric accommodation in laboratory settings. It is, however, unknown whether it exerts similar ameliorating effect in humans and whether needleless transcutaneous electroacupuncture (TEA) is also effective in improving gastric accommodation.

AIM

The aim was to investigate the effects of TEA on gastric accommodation, gastric slow waves, and dyspeptic related symptoms.

METHODS

Thirteen healthy volunteers were studied in four randomized sessions: control, cold nutrient liquid, cold nutrient liquid + sham-TEA, and cold nutrient liquid + TEA. The subjects were requested to drink Ensure until reaching maximum satiety. The electrogastrogram (EGG) and electrocardiogram (ECG) were recorded to assess the gastric and autonomic functions respectively.

RESULTS

1) Gastric accommodation was reduced with the cold drink in comparison with the warm drink (P = 0.023). TEA improved the impaired gastric accommodation from 539.2 ± 133.8 ml to 731.0 ± 185.7 ml (P = 0.005). 2) The percentage of normal gastric slow waves in six subjects was significantly decreased in the cold session (P = 0.002) and improved in the TEA session (P = 0.009 vs sham; P < 0.001 vs cold). 3) TEA showed significant improvement in the bloating (80.8 ± 5.7 vs 61.2 ± 26.2, P = 0.011), postprandial fullness (48.1 ± 12.0 vs 34.2 ± 21.2, P = 0.042), and nausea (29.6 ± 10.9 vs 19.2 ± 11.2, P = 0.026) in comparison with sham-TEA session. 4) Neither cold drink nor TEA altered vagal activities (P > 0.05).

CONCLUSIONS

TEA improves impaired gastric accommodation and slow waves induced by cold drink and the effect does not seem to be mediated via the vagal mechanisms.

Altered postprandial responses in gastric myoelectrical activity and cardiac autonomic functions in healthy obese subjects

BACKGROUND

It is unknown whether gastric myoelectrical activity (GMA) and autonomic functions are altered in obesity. The aims of this study were to investigate GMA and autonomic functions in obese subjects and to compare their responses to different meals with lean subjects.

METHODS

The study was performed in 12 lean and 12 obese subjects. GMA was measured using electrogastrography, and autonomic functions were assessed using spectral analysis of heart rate variability.

RESULTS

The study achieved the following key results: (1) Compared to lean subjects, obese subjects showed unaltered gastric slow waves at baseline but enhanced responses to both fatty and protein meals. The lean subjects showed a reduced percentage of normal gastric slow waves with a fatty meal, which was not seen in obese subjects; lean subjects showed no changes in the dominant frequency or power of the gastric slow waves with a protein meal, whereas both of these parameters were increased in obese subjects. (2) Autonomic functions were altered in obese subjects in both fasting and fed states. Obese subjects showed an increased sympathetic activity in the fasting state, but absence of a normal postprandial response in sympathovagal balance to both fatty and protein meals.

CONCLUSIONS

The findings on gastric slow waves demonstrate that obese subjects are more receptive to fatty meals and more responsive to protein meals. Obese subjects have impaired autonomic functions in both fasting and fed states. The alterations in gastric and autonomic functions may contribute to eating disorders in the obese.

Recent progress in gastric arrhythmia: pathophysiology, clinical significance and future horizons

Gastric arrhythmia continues to be of uncertain diagnostic and therapeutic significance. However, recent progress has been substantial, with technical advances, theoretical insights and experimental discoveries offering new translational opportunities. The discoveries that interstitial cells of Cajal (ICC) generate slow waves and that ICC defects are associated with dysmotility have reinvigorated gastric arrhythmia research. Increasing evidence now suggests that ICC depletion and damage, network disruption and channelopathies may lead to aberrant slow wave initiation and conduction. Histological and high-resolution (HR) electrical mapping studies have now redefined the human 'gastric conduction system', providing an improved baseline for arrhythmia research. The application of HR mapping to arrhythmia has also generated important new insights into the spatiotemporal dynamics of arrhythmia onset and maintenance, resulting in the emergence of new provisional classification schemes. Meanwhile, the strong associations between gastric functional disorders and electrogastrography (EGG) abnormalities (e.g. in gastroparesis, unexplained nausea and vomiting and functional dyspepsia) continue to motivate deeper inquiries into the nature and causes of gastrointestinal arrhythmias. In future, technical progress in EGG methods, new HR mapping devices and software, wireless slow wave acquisition systems and improved gastric pacing devices may achieve validated applications in clinical practice. Neurohormonal factors in arrhythmogenesis also continue to be elucidated and a deepening understanding of these mechanisms may open opportunities for drug design for treating arrhythmias. However, for all translational goals, it remains to be seen whether arrhythmia can be corrected in a way that meaningfully improves organ function and symptoms in patients.

Visceral hypersensitivity and electromechanical dysfunction as therapeutic targets in pediatric functional dyspepsia

Functional gastrointestinal disorders (FGID) are common clinical syndromes diagnosed in the absence of biochemical, structural, or metabolic abnormalities. They account for significant morbidity and health care expenditures and are identifiable across variable age, geography, and culture. Etiology of abdominal pain associated FGIDs, including functional dyspepsia (FD), remains incompletely understood, but growing evidence implicates the importance of visceral hypersensitivity and electromechanical dysfunction. This manuscript explores data supporting the role of visceral hypersensitivity and electromechanical dysfunction in FD, with focus on pediatric data when available, and provides a summary of potential therapeutic targets.

Impairment of the proximal to distal tonic gradient in the human diabetic stomach

BACKGROUND

Little has been known about the contractile characteristics of diabetic stomach. We investigated spontaneous contractions and responses to acetylcholine in the gastric muscle in diabetic patients and non-diabetic control subjects according to the region of stomach.

METHODS

Gastric specimens were obtained from 26 diabetics and 55 controls who underwent gastrectomy at Samsung Medical Center between February 2008 and November 2011. Isometric force measurements were performed using circular muscle strips from the different regions of stomach under basal condition and in response to acetylcholine.

KEY RESULTS

Basal tone of control was higher in the proximal stomach than in the distal (0.63 g vs 0.46 g, p = 0.027). However, in diabetics, basal tone was not significantly different between the proximal and distal stomach (0.75 g vs 0.62 g, p = 0.32). The distal stomach of diabetics had higher basal tone and lower frequency than that of control (0.62 g vs 0.46 g, p = 0.049 and 4.0/min vs 4.9/min, p = 0.049, respectively). After exposure to acetylcholine, dose-dependent increases of basal tone, peak, and area under the curve (AUC) were noticed in both proximal and distal stomach of the two groups. In the proximal stomach, however, the dose-dependent increase of basal tone and AUC was less prominent in diabetics than in control.

CONCLUSIONS & INFERENCES

On the contrary to control, the proximal to distal tonic gradient was not observed in diabetic stomach. Diabetic stomach also had lower frequency of spontaneous contraction in the distal stomach and less acetylcholine-induced positive inotropic effect in the proximal stomach than control.

The Effects of Banha-sasim-tang on Dyspeptic Symptoms and Gastric Motility in Cases of Functional Dyspepsia: A Randomized, Double-Blind, Placebo-Controlled, and Two-Center Trial

Introduction. Functional dyspepsia (FD) is highly prevalent, and no standard treatments exist for this condition. Herbal prescriptions are widely used to treat FD. In traditional Korean medicine, Banha-sasim-tang (BST) is a famous herbal prescription for dyspepsia. This study aimed to evaluate the efficacy of BST and to examine the relationship between gastric slow waves and dyspeptic symptoms. Materials and Methods. In total, 100 FD patients were recruited; BST or placebo was administered for 6 weeks. The gastrointestinal symptom scale, FD-related quality of life scale, and frequency or power variables regarding gastric slow waves were measured at 0, 6, and 14 weeks. Results. There were no significant differences in the overall dyspeptic symptoms or quality of life between the BST and placebo groups. However, early satiety was significantly improved in the BST group (P = 0.009, at 6 weeks by intention-to-treat analysis). Abnormal gastric dysrhythmias and power ratios were also significantly improved by BST. Conclusion. BST had no significant effects on FD. However, early satiety appeared to improve after BST administration. Electrogastrography may be a useful technique for assessing changes in gastric motility dysfunction after interventions for FD. Further investigation focused on specific symptoms or subtypes of FD is required.

Abnormal initiation and conduction of slow-wave activity in gastroparesis, defined by high-resolution electrical mapping

BACKGROUND & AIMS

Interstitial cells of Cajal (ICC) generate slow waves. Disrupted ICC networks and gastric dysrhythmias are each associated with gastroparesis. However, there are no data on the initiation and propagation of slow waves in gastroparesis because research tools have lacked spatial resolution. We applied high-resolution electrical mapping to quantify and classify gastroparesis slow-wave abnormalities in spatiotemporal detail.

METHODS

Serosal high-resolution mapping was performed using flexible arrays (256 electrodes; 36 cm(2)) at stimulator implantation in 12 patients with diabetic or idiopathic gastroparesis. Data were analyzed by isochronal mapping, velocity and amplitude field mapping, and propagation animation. ICC numbers were determined from gastric biopsy specimens.

RESULTS

Mean ICC counts were reduced in patients with gastroparesis (2.3 vs 5.4 bodies/field; P < .001). Slow-wave abnormalities were detected by high-resolution mapping in 11 of 12 patients. Several new patterns were observed and classified as abnormal initiation (10/12; stable ectopic pacemakers or diffuse focal events; median, 3.3 cycles/min; range, 2.1-5.7 cycles/min) or abnormal conduction (7/10; reduced velocities or conduction blocks; median, 2.9 cycles/min; range, 2.1-3.6 cycles/min). Circumferential conduction emerged during aberrant initiation or incomplete block and was associated with velocity elevation (7.3 vs 2.9 mm s(-1); P = .002) and increased amplitudes beyond a low base value (415 vs 170 μV; P = .002).

CONCLUSIONS

High-resolution mapping revealed new categories of abnormal human slow-wave activity. Abnormalities of slow-wave initiation and conduction occur in gastroparesis, often at normal frequency, which could be missed by tests that lack spatial resolution. Irregular initiation, aberrant conduction, and low amplitude activity could contribute to the pathogenesis of gastroparesis.

Movement based artifacts may contaminate extracellular electrical recordings from GI muscles

BACKGROUND

Electrical slow waves drive peristaltic contractions in the stomach and facilitate gastric emptying. In gastroparesis and other disorders associated with altered gastric emptying, motility defects have been related to altered slow wave frequency and disordered propagation. Experimental and clinical measurements of slow waves are made with extracellular or abdominal surface recording.

METHODS

We tested the consequences of muscle contractions and movement on biopotentials recorded from murine gastric muscles with array electrodes and pairs of silver electrodes.

KEY RESULTS

Propagating biopotentials were readily recorded from gastric sheets composed of the entire murine stomach. The biopotentials were completely blocked by nifedipine (2 μmol L(-1) ) that blocked contractile movements and peristaltic contractions. Wortmannin, an inhibitor of myosin light chain kinase, also blocked contractions and biopotentials. Stimulation of muscles with carbachol increased the frequency of biopotentials in control conditions but failed to elicit biopotentials with nifedipine or wortmannin present. Intracellular recording with microelectrodes showed that authentic gastric slow waves occur at a faster frequency typically than biopotentials recorded with extracellular electrodes, and electrical slow waves recorded with intracellular electrodes were unaffected by suppression of movement. Electrical transients, equal in amplitude to biopotentials recorded with extracellular electrodes, were induced by movements produced by small transient stretches (<1 mm) of paralyzed or formalin fixed gastric sheets.

CONCLUSIONS & INFERENCES

These data demonstrate significant movement artifacts in extracellular recordings of biopotentials from murine gastric muscles and suggest that movement suppression should be an obligatory control when monitoring electrical activity and characterizing propagation and coordination of electrical events with extracellular recording techniques.

Analysis of pacemaker activity in the human stomach

Extracellular electrical recording and studies using animal models have helped establish important concepts of human gastric physiology. Accepted standards include electrical quiescence in the fundus, 3 cycles per minute (cpm) pacemaker activity in corpus and antrum, and a proximal-to-distal slow wave frequency gradient. We investigated slow wave pacemaker activity, contractions and distribution of interstitial cells of Cajal (ICC) in human gastric muscles. Muscles were obtained from patients undergoing gastric resection for cancer, and the anatomical locations of each specimen were mapped by the operating surgeon to 16 standardized regions of the stomach. Electrical slow waves were recorded with intracellular microelectrodes and contractions were recorded by isometric force techniques. Slow waves were routinely recorded from gastric fundus muscles. These events had similar waveforms as slow waves in more distal regions and were coupled to phasic contractions. Gastric slow wave frequency was significantly greater than 3 cpm in all regions of the stomach. Antral slow wave frequency often exceeded the highest frequency of pacemaker activity in the corpus. Chronotropic mechanisms such as muscarinic and prostaglandin receptor binding, stretch, extracelluar Ca(2+) and temperature were unable to explain the observed slow wave frequency that exceeded accepted normal levels. Muscles from all regions through the thickness of the muscularis demonstrated intrinsic pacemaker activity, and this corresponded with the widespread distribution in ICC we mapped throughout the tunica muscularis. Our findings suggest that extracellular electrical recording has underestimated human slow wave frequency and mechanisms of human gastric function may differ from standard laboratory animal models.

Banha-sasim-tang as an herbal formula for the treatment of functional dyspepsia: a randomized, double-blind, placebo-controlled, two-center trial

BACKGROUND

Functional dyspepsia (FD) is characterized by a high prevalence rate and no standard conventional treatments. Alternative therapies, such as herbal formulas, are widely used to treat FD. However, there are inadequate evidences regarding the safety and efficacy of these formulas. Moreover, the mechanisms by which herbal formulas act in the gastrointestinal tract are controversial. In traditional Korean medicine, Banha-sasim-tang has long been one of the most frequently prescribed herbal formulas for treating dyspepsia. The current study is designed to evaluate the efficacy and safety of Banha-sasim-tang for FD patients and to examine whether there will be a significant correlation between cutaneous electrogastrography recordings and dyspeptic symptoms in FD patients, and between changes in gastric myoelectrical activity and improvement in dyspeptic symptoms during Banha-sasim-tang administration.

METHODS

This randomized, double-blind, placebo-controlled trial will be performed at two centers and will include a Banha-sasim-tang group and placebo group. Each group will consist of 50 FD patients. Six weeks of administration of Banha-sasim-tang or placebo will be conducted. During the subsequent 2 months, follow-up observations of primary and secondary outcomes will be performed. The primary outcomes are differences as measured on the gastrointestinal symptom scale, and the secondary outcomes are differences as measured on the visual analogue scale for dyspepsia and on the questionnaire for FD-related quality of life. All outcomes will be measured at baseline, at 2, 4, and 6 weeks of treatment, and at the 1 and 2 month follow-up. Cutaneous electrogastrography will be performed and assessed at baseline and at 6 weeks.

DISCUSSION

This trial will provide evidence of the safety and efficacy of Banha-sasim-tang for the treatment for FD. Furthermore, based on the assessment of the relationship between cutaneous electrogastrography recordings and dyspeptic symptoms in this trial, the possibility of clinical applications of cutaneous electrogastrography in the treatment of FD will be elucidated.

TRIAL REGISTRATION

Current Controlled Trials (ISRCTN 51910678); Clinical Trials.gov Identifier: NCT00987805.

Gastric motor and sensory function

PURPOSE OF REVIEW

Abnormalities of gastric sensory and motor function are considered key players in the pathogenesis of upper gastrointestinal symptoms in functional dyspepsia and in gastroparesis. This review summarizes recent progress in our understanding of gastric sensory and motor function in health and in disease.

RECENT FINDINGS

Although assessment of gastric emptying rate is often used in the clinical work-up of patients with functional dyspepsia or gastroparesis, the correlation with symptoms is generally poor. Central processing, related to psychosocial dysfunction, is increasingly implicated in the pathogensis of gastric hypersensitivity. Meal challenge test and in fact even simple ingestion of a meal induce increased symptom occurrence in functional dyspepsia. Impaired motor function in critically ill patients is increasingly being studied and recognized as a prognostically relevant factor. Studies have reported on pharmacological approaches as well as electrical stimulation in the treatment of gastric sensorimotor dysfunction.

SUMMARY

Progress in our understanding of the normal and abnormal gastric sensory and motor function may lead to new or improved treatment modalities. Areas of recent advances are the role of the central nervous system in visceral hypersensitivity, motor abnormalities of the stomach in critically ill patients and the exploration of novel pharmacotherapeutic approaches.

Clinical significance of serum pepsinogen I and II and gastrin-17 in patients with functional dyspepsia

AIM: To investigate the clinical significance of serum pepsinogen (PG) I and II and gastrin-17 (G-17) in patients with functional dyspepsia (FD).

METHODS: A case-control study was performed. Two hundreds and twenty-nine FD patients recruited were diagnosed according to Rome III criteria. Serum PG I and II and G-17 levels were measured by enzyme-linked immunosorbent assay (ELISA). The PG I/II ratio (PGR) was calculated. Serum IgG antibody against Helicobacter pylori (H. pylori) was determined by ELISA to evaluate H. pylori infection.

RESULTS: In FD patients, the PGR was lower in the ≥ 61 age group than in the ≤ 40 age group (P = 0.049). The levels of serum PG II and G-17 were significantly higher in FD patients than in normal controls (both P = 0.000), while the PGR was significantly lower in FD patients than in normal controls (P = 0.000). No significant difference was noted in serum PG I level between FD patients and normal controls (P = 0.067). The receiver operating characteristic (ROC) curve analysis showed that the optimal cut-off points of PG II and G-17 values for the diagnosis of FD were 13.2 μg/L (sensitivity 52.8%, specificity 100%, and accuracy 67.5%) and 6.84 μg/L (sensitivity 52.8%, specificity 100%, and accuracy 67.5%), respectively. The levels of serum PG I and PG II were significantly higher in male FD patients than in female ones (P = 0.003 and 0.004, respectively). The positive rate of serum IgG antibody against H. pylori was higher in FD patients than in normal controls (P = 0.028).

CONCLUSION: The levels of serum PGII and G-17 are elevated in FD patients, which may suggest functional changes in gastric sinus and proximal duodenal mucosa. There is an association between FD and H. pylori infection.