Gastroparesis: clinical update

Poor Gastric Emptying in Patients with Paraesophageal Hernias: Pyloroplasty, Per-Oral Pyloromyotomy, BoTox, or Wait and See?

Gastric emptying delay may be caused with both functional and anatomic derangements. Gastroparesis is suspected in patients presenting with certain foregut symptoms without anatomic obstruction. Data are still emerging regarding the best treatment of this condition. In cases where large paraesophageal hernias alter the upper gastrointestinal anatomy, it is difficult to know if gastroparesis also exists. Management of hiatal hernias is also still evolving, with various strategies to reduce recurrence being actively investigated. In this article, we present a systematic review of the existing literature around the management of gastroparesis and the management of paraesophageal hernias when they occur separately. In addition, since there are limited data to guide diagnosis and management of these conditions when they are suspected to coexist, we provide a rational strategy based on our own experience in patients with paraesophageal hernias who have symptoms or studies that raise suspicion for a coexisting functional disorder.

Computational modeling of drug dissolution in the human stomach: Effects of posture and gastroparesis on drug bioavailability

The oral route is the most common choice for drug administration because of several advantages, such as convenience, low cost, and high patient compliance, and the demand and investment in research and development for oral drugs continue to grow. The rate of dissolution and gastric emptying of the dissolved active pharmaceutical ingredient (API) into the duodenum is modulated by gastric motility, physical properties of the pill, and the contents of the stomach, but current in vitro procedures for assessing dissolution of oral drugs are limited in their ability to recapitulate this process. This is particularly relevant for disease conditions, such as gastroparesis, that alter the anatomy and/or physiology of the stomach. In silico models of gastric biomechanics offer the potential for overcoming these limitations of existing methods. In the current study, we employ a biomimetic in silico simulator based on the realistic anatomy and morphology of the stomach (referred to as "StomachSim") to investigate and quantify the effect of body posture and stomach motility on drug bioavailability. The simulations show that changes in posture can potentially have a significant (up to 83%) effect on the emptying rate of the API into the duodenum. Similarly, a reduction in antral contractility associated with gastroparesis can also be found to significantly reduce the dissolution of the pill as well as emptying of the API into the duodenum. The simulations show that for an equivalent motility index, the reduction in gastric emptying due to neuropathic gastroparesis is larger by a factor of about five compared to myopathic gastroparesis.

POEM, GPOEM, and ZPOEM

Our tripartite narrative review discusses Peroral Endoscopic Myotomy (POEM), gastric POEM (GPOEM) and POEM for Zenker's diverticula (ZPOEM). POEM is the prototypical procedure that launched the novel "3rd space endoscopy" field of advanced endoscopy. It revolutionized achalasia therapy by offering a much less invasive version of the prior gold standard, the laparoscopic Heller myotomy (HM). We review in detail indications, outcomes, technique variations and comparative data between POEM and HM particularly with regard to the hotly debated issue of GERD. We then proceed to discuss two less illustrious but nevertheless important offshoots of the iconic POEM procedure: GPOEM for gastroparesis and ZPOEM for the treatment of hypopharyngeal diverticula. For GPOEM, we discuss the rationale of pylorus-directed therapies, briefly touch on GPOEM technique variations and then focus on the importance of proper patient selection and emerging data in this area. On the third and final part of our review, we discuss ZPOEM and expound on technique variations including our "ultra-short tunnel technique". Our review emphasizes that, despite the superiority of endoscopy over surgery for the treatment of hypopharyngeal diverticula, there is no clear evidence yet of the superiority of the newfangled ZPOEM technique compared to the conventional endoscopic myotomy technique practiced for over two decades prior to the advent of ZPOEM.

Spinal cord injury-mediated changes in electrophysiological properties of rat gastric nodose ganglion neurons

In preclinical rodent models, spinal cord injury (SCI) manifests as gastric vagal afferent dysfunction both acutely and chronically. However, the mechanism that underlies this dysfunction remains unknown. In the current study, we examined the effect of SCI on gastric nodose ganglia (NG) neuron excitability and on voltage-gated Na⁺ (Na_V) channels expression and function in rats after an acute (i.e. 3-days) and chronic (i.e. 3-weeks) period. Rats randomly received either T3-SCI or sham control surgery 3-days or 3-weeks prior to experimentation as well as injections of 3% DiI solution into the stomach to identify gastric NG neurons. Single cell qRT-PCR was performed on acutely dissociated DiI-labeled NG neurons to measure Na_V1.7, Na_V1.8 and Na_V1.9 expression levels. The results indicate that all 3 channel subtypes decreased. Current- and voltage-clamp whole-cell patch-clamp recordings were performed on acutely dissociated DiI-labeled NG neurons to measure active and passive properties of C- and A-fibers as well as the biophysical characteristics of Na_V1.8 channels in gastric NG neurons. Acute and chronic SCI did not demonstrate deleterious effects on either passive properties of dissociated gastric NG neurons or biophysical properties of Na_V1.8. These findings suggest that although Na_V gene expression levels change following SCI, Na_V1.8 function is not altered. The disruption throughout the entirety of the vagal afferent neuron has yet to be investigated.

Classification of gastric emptying and orocaecal transit through artificial neural networks

Classical quantification of gastric emptying (GE) and orocaecal transit (OCT) based on half-life time T$ _{50} $, mean gastric emptying time (MGET), orocaecal transit time (OCTT) or mean caecum arrival time (MCAT) can lead to misconceptions when analyzing irregularly or noisy data. We show that this is the case for gastrointestinal transit of control and of diabetic rats. Addressing this limitation, we present an artificial neural network (ANN) as an alternative tool capable of discriminating between control and diabetic rats through GE and OCT analysis. Our data were obtained via biological experiments using the alternate current biosusceptometry (ACB) method. The GE results are quantified by T$ _{50} $ and MGET, while the OCT is quantified by OCTT and MCAT. Other than these classical metrics, we employ a supervised training to classify between control and diabetes groups, accessing sensitivity, specificity, $ f_1 $ score, and AUROC from the ANN. For GE, the ANN sensitivity is 88%, its specificity is 83%, and its $ f_1 $ score is 88%. For OCT, the ANN sensitivity is 100%, its specificity is 75%, and its $ f_1 $ score is 85%. The area under the receiver operator curve (AUROC) from both GE and OCT data is about 0.9 in both training and validation, while the AUCs for classical metrics are 0.8 or less. These results show that the supervised training and the binary classification of the ANN was successful. Classical metrics based on statistical moments and ROC curve analyses led to contradictions, but our ANN performs as a reliable tool to evaluate the complete profile of the curves, leading to a classification of similar curves that are barely distinguished using statistical moments or ROC curves. The reported ANN provides an alert that the use of classical metrics can lead to physiological misunderstandings in gastrointestinal transit processes. This ANN capability of discriminating diseases in GE and OCT processes can be further explored and tested in other applications.

Altered physiology of gastrointestinal vagal afferents following neurotrauma

The adaptability of the central nervous system has been revealed in several model systems. Of particular interest to central nervous system-injured individuals is the ability for neural components to be modified for regain of function. In both types of neurotrauma, traumatic brain injury and spinal cord injury, the primary parasympathetic control to the gastrointestinal tract, the vagus nerve, remains anatomically intact. However, individuals with traumatic brain injury or spinal cord injury are highly susceptible to gastrointestinal dysfunctions. Such gastrointestinal dysfunctions attribute to higher morbidity and mortality following traumatic brain injury and spinal cord injury. While the vagal efferent output remains capable of eliciting motor responses following injury, evidence suggests impairment of the vagal afferents. Since sensory input drives motor output, this review will discuss the normal and altered anatomy and physiology of the gastrointestinal vagal afferents to better understand the contributions of vagal afferent plasticity following neurotrauma.

Prucalopride in diabetic and connective tissue disease-related gastroparesis: Randomized placebo-controlled crossover pilot trial

BACKGROUND

Gastroparesis, defined by delayed gastric emptying in the absence of mechanical outlet obstruction, is a frequent neuropathic complication of diabetes mellitus, and effective treatments are lacking. Prucalopride is a pan-gut prokinetic with selective agonist effects on serotonin 5-HT4 receptors in the gut. This study aimed to assess the effect of prucalopride 4 mg daily on Gastroparesis Cardinal Symptom Index (GCSI), meal-related symptom score (MRSS), and gastric emptying rate in diabetic or connective tissue disease (CTD)-related gastroparesis patients.

METHODS

This was a double-blind crossover trial of four-week treatment periods with prucalopride or placebo divided by two weeks of washout. GSCI, MRSS, gastric emptying scintigraphy, PAGI-SYM, and PAGI-QoL were assessed at baseline and the end of each treatment period. Daily bowel movement (BM) frequency and gastrointestinal symptoms were recorded in each period.

KEY RESULTS

Fifteen gastroparesis patients (13 diabetic, 2 CTD) were enrolled. GCSI scores were lower than baseline but not different between treatment arms. MRSS scores over time or cumulative score were not significantly different between groups. Gastric emptying was more rapid in the prucalopride treatment period, with mean four-hour meal retention of 22 ± 6% in PRU period vs 40 ± 9% in the placebo period (P = 0.05). Weekly BM frequency was significantly higher in prucalopride than placebo periods (10.5 ± 1.8 vs 7.5 ± 0.8, P < 0.0001). Perception of weight loss was higher in patients on prucalopride. Analysis of diabetic gastroparesis (n = 13) population did not change the conclusions.

CONCLUSION AND INFERENCE

Prucalopride at 4 mg accelerates gastric emptying and bowel movement frequency but does not appear to ameliorate gastroparesis or meal-related symptoms in this study.

Initial Experience with Endoscopic Pyloromyotomy, with Description and Video of Technique

BACKGROUND

Gastric per oral endoscopic myotomy (G-POEM) is a recently developed incisionless procedure to address gastroparesis. It has been previously described to treat medical and postsurgical gastroparesis. The present study is a case series of patients undergoing G-POEM for a variety of indications, both elective and urgent.

METHODS

IRB approval was obtained for retrospective review of a prospectively collected database including patients who underwent G-POEM during a 1.5-year period. Using an upper endoscope, a mucosotomy is made 2 cm proximal to the pylorus on the anterior surface of the stomach. A submucosal tunnel is made to the pylorus muscle, which is completed incised. When possible, Endoflip® was used to evaluate pyloric distensibility before and after the myotomy. Patient demographic factors, additional procedures, and other follow-up were collected by chart review. Elective cases were offered repeat gastric emptying study at 6 months.

RESULTS

There were 17 patients available for review. The procedure was technically completed in all cases. There was one gastric perforation recognized on postoperative day two that was addressed with laparoscopy and omental patch. Median length of stay was zero days, and 13/17 (76%) of patients experienced symptomatic relief. Pyloric distensibility significantly decreased intraoperatively from 5.6 (± 1.7) to 10.8 (± 5.0) cm²/mmHg (p = 0.002).

CONCLUSION

This limited case series demonstrates G-POEM to be a versatile procedure able to address gastroparesis in a variety of settings. Success rates are congruent with previously published reports, and one serious complication was able to be addressed laparoscopically. Endoflip® was able to verify a successful myotomy intraoperatively. This procedure is an attractive alternative to less effective non-invasive treatments and a more invasive laparoscopic pyloroplasty.

Acupuncture in Inflammatory Bowel Disease

Scientific research into the effects and mechanisms of acupuncture for gastrointestinal diseases including inflammatory bowel disease has been rapidly growing in the past several decades. In this review, we discuss the history, theory, and methodology of acupuncture and review potentially beneficial mechanisms of action of acupuncture for managing inflammatory bowel disease. Acupuncture has been shown to decrease disease activity and inflammation via increase of vagal activity in inflammatory bowel disease. Acupuncture has demonstrated beneficial roles in the regulation of gut dysbiosis, intestinal barrier function, visceral hypersensitivity, gut motor dysfunction, depression/anxiety, and pain, all of which are factors that can significantly impact quality of life in patients with inflammatory bowel disease. A number of clinical trials have been performed to investigate the therapeutic effects of acupuncture in ulcerative colitis and Crohn's disease. Although the data from these trials are promising, more studies are needed given the heterogeneous and multifactorial aspects of inflammatory bowel disease. There is also an important need to standardize acupuncture methodology, study designs, and outcome measurements.

Gastric per-oral endoscopic myotomy: Current status and future directions

Gastroparesis, or symptomatic delayed gastric emptying in the absence of mechanical obstruction, is a challenging and increasingly identified syndrome. Medical options are limited and the only medication approved by the Food and Drug Administration for treatment of gastroparesis is metoclopramide, although other agents are frequently used off label. With this caveat, first-line treatments for gastroparesis include dietary modifications, antiemetics and promotility agents, although these therapies are limited by suboptimal efficacy and significant medication side effects. Treatment of patients that fail first-line treatments represents a significant therapeutic challenge. Recent advances in endoscopic techniques have led to the development of a promising novel endoscopic therapy for gastroparesis via endoscopic pyloromyotomy, also referred to as gastric per-oral endoscopic myotomy or per-oral endoscopic pyloromyotomy. The aim of this article is to review the technical aspects of the per-oral endoscopic myotomy procedure for the treatment of gastroparesis, provide an overview of the currently published literature, and outline potential next directions for the field.

Cajal Cell Counts are Important Predictors of Outcomes in Drug Refractory Gastroparesis Patients With Neurostimulation

BACKGROUND AND AIMS

Cajal cells serve as the pacemaker cells of the gastrointestinal tract and regulates peristalsis. On the baisis of that fact, it has been hypothesized that a decrease in Cajal cells can lead to gastroparesis and other motility issues. Treatment with medications has a limited efficacy and most resort to gastric electrical stimulation (GES) devices for symptomatic relief. We believe that the number of Cajal cells present is directly proportional to symptomatic relief with GES.

MATERIALS AND METHODS

Twenty-three (white female) subjects were recruited from the gastric motility clinic University of Mississipi for this study with the criteria of drug refractory gastropersis. Symptoms were measured using Likert scale and gastric emptying times were measured pre-GES and post-GES. Serosal electrogram measurements were recorded during surgical placement of permanent electrical stimulator under various modes. Cajal cell count scoring via immunohistochemistry were performed during the implantaion of the GES.

RESULTS

The data were grouped in 2 categories based on the Cajal cells that is ≥2.00 and <2.00. Subjects with higher Cajal cells reported a statiscially improvement in gastroperesis symptoms. Significant differences were also noted in the first hour gastric emptying study. The mean group difference is 17.5 (95% confidence interval, 1.41-33.58; P=0.035). Serosal amplitude differences were noted being significantly higher in the group with ≥2 cajal cells.

CONCLUSIONS

Electrograms obtained after GES demonstrates immediate improvement in gastric electrical activity and gastroparesis symptoms in patients with relatively higher Cajal cell counts when compared with patients with extensive loss of Cajal cells.

Association between duration or etiology of gastroparesis and clinical response after gastric per-oral endoscopic pyloromyotomy

BACKGROUND AND AIMS

Gastric per-oral endoscopic pyloromyotomy (GPOEM) is a novel procedure with promising potential for the treatment of gastroparesis but with limited data regarding predictors of clinical response. This study aims to evaluate the safety and efficacy of the procedure and explore the impact of duration and etiology (diabetic vs nondiabetic) of gastroparesis on clinical outcome as measured by the Gastroparesis Cardinal Symptom Index (GCSI).

METHODS

A single-center retrospective longitudinal study at a tertiary care hospital was performed over an 18-month period. Forty patients with refractory gastroparesis (25 nondiabetic and 15 diabetic patients) were included.

RESULTS

GCSI significantly improved throughout the study period (F[2.176, 17.405] = 10.152, P = .001). The nausea/vomiting subscale showed sustained improvement through 18 months (F[2.213, 17.704] = 15.863, P < .00001). There was no significant improvement in bloating (F[2.099, 16.791] = 1.576, P = .236). Gastric scintigraphy retention was significantly reduced by 41.7% (t = -7.90; P < .00001). Multivariate linear regression modeling revealed a significant correlation between the duration of disease and a GCSI improvement at 12 months (P = .02), with a longer duration of disease associated with a poorer long-term response. The etiology of gastroparesis was not associated with clinical improvement (P = .16). Adverse events (7.5%) included 1 capnoperitoneum, 1 periprocedure chronic obstructive pulmonary disease exacerbation, and 1 mucosotomy closure site disruption.

CONCLUSIONS

GPOEM appears to be a safe and effective minimally invasive therapy for refractory gastroparesis, especially for patients with predominant nausea/vomiting and shorter duration of disease, regardless of the etiology. We propose the clinical criteria for undergoing GPOEM should be a GCSI of at least 2.0 and a gastric retention of greater than 20%.

Gastric Peroral Endoscopic Pyloromyotomy Reduces Symptoms, Increases Quality of Life, and Reduces Health Care Use For Patients With Gastroparesis

BACKGROUND & AIMS

Gastric peroral endoscopic pyloromyotomy (GPOEM) is becoming a promising treatment option for patients with refractory gastroparesis. We aimed to systematically assess the efficacy of GPOEM and its effects on health care use.

METHODS

We performed a retrospective study on 30 patients with refractory gastroparesis who underwent GPOEM from June 2015 through July 2017 at a tertiary center. We compared outcomes with those of 7 patients with refractory gastroparesis who did not undergo the procedure (controls). The primary outcomes were patient-reported reductions in symptoms, based on the gastroparesis cardinal symptom index (GCSI), and increases in 8 aspects of quality of life, based on Short Form 36 (SF-36) scores. Data were collected on the day of the procedure (baseline) and at 1 month, 6 months, 12 months, and 18 months afterward. Secondary outcomes included visits to the emergency department or hospitalization for gastroparesis-related symptoms.

RESULTS

GPOEM was technically successful in all patients and significantly reduced GCSI scores in repeated-measure analysis of variance (F_{2.044, 38.838} = 22.319; P < .0005). The mean score at baseline was 3.5 ± 0.6, at 1 month after GPOEM was 1.8 ± 1.0 (P < .0005), at 6 months after was 1.9 ± 1.2 (P < .0005), at 12 months after was 2.6 ± 1.5 (P < .026), and at 18 months after was 2.1 ± 1.3 (P < .016). GPOEM was associated with improved quality of life: 77.8%, 76.5%, and 70% of patients had significant increases in SF-36 scores, compared with baseline, at 1 month, 6 months, and 12 months after GPOEM, respectively (F_1.71,18.83 = 14.16; P < .0005). Compared with controls, patients who underwent GPOEM had significant reductions in GCSI, after we controlled for baseline score and duration of the disease (F_1,31 = 9.001; P = .005). Patients who received GPOEM had significant reductions in number of emergency department visits (from 2.2 ± 3.1 times/mo at baseline to 0.3 ± 0.8 times/mo; P = .003) and hospitalizations (from 1.7 ± 2 times/mo at baseline to 0.2 ± 0.4 times/mo; P = .0002).

CONCLUSIONS

In a retrospective study of patients who underwent GPOEM for refractory gastroparesis, we found the procedure significantly improved symptoms, increased quality of life, and reduced health care use related to gastroparesis.

Technical Aspects of Peroral Endoscopic Pyloromyotomy

Gastric peroral endoscopic pyloromyotomy (G-POEM or POP) is a feasible and effective procedure for the treatment of refractory gastroparesis. G-POEM is a technically demanding endoscopic procedure. As of yet, there is no consensus on the technique. A variety of techniques have been reported in published studies. The essential technical steps of the procedure are (1) establishment of submucosal tunnel in gastric antrum, (2) identification of the pyloric muscular ring, (3) selective circular myotomy, and (4) a 2.5-cm to 3.0-cm length of myotomy. There are still some technical questions unanswered, and more studies are needed to establish standardized techniques and possible improvement of outcomes.

Autonomic testing, methods and techniques

The evaluation of autonomic function requires indirect assessment of neurophysiologic function using specialized equipment that is often available only at tertiary care centers, with few specialists available. However, the evaluation of autonomic function is rooted in basic physiology, and the results can be interpreted by careful consideration of the context of the problem. Many automated devices have become widely available to test autonomic function, but they tend to gather inadequate data leading to frequent misdiagnosis and clinical confusion. We review the details necessary for the neurophysiologist to properly perform, and interpret, autonomic function testing.

Efficacy of needleless transcutaneous electroacupuncture in synchronization with breathing for symptomatic idiopathic gastroparesis: A blinded and controlled acute treatment trial

BACKGROUND

Needleless transcutaneous electroacupuncture (TEA) improves nausea and myoelectrical activity in diabetic gastroparesis (GP). Synchronized TEA (STEA), which combines synchronized breathing with TEA, is more potent than TEA in enhancing vagal activity in healthy subjects.

AIMS

To investigate whether STEA improves symptoms, electrogastrogram (EGG) and vagal activity in idiopathic gastroparesis (IGP).

METHODS

Eighteen IGP subjects underwent 2 randomized visits (sham at non-acupoints or real STEA at acupoints) consisted of a 30-minute baseline, an Ensure challenge to provoke nausea, followed by 60-minute treatment with sham or real STEA, and 15-minute observation period. Severity of nausea, EGG, and vagal activity (based on electrocardiogram and serum Pancreatic Polypeptide, PP) were recorded.

RESULTS

In sham or STEA, the nausea scores of 2.7 ± 0.5 and 1.9 ± 0.5 at fasting baseline, respectively, increased to 5.9 ± 0.4 and 5.8 ± 0.3 during Ensure test (P < .05, vs baseline), subsequently reduced to 3.4 ± 0.6 with sham or 3.6 ± 0.6 with STEA, respectively (P < .05, vs Ensure period). Experiments with sham and STEA started with similar % of normal waves on EGG (66.4 ± 3.9 and 61.8 ± 3.0, respectively); decreased to 63. 5 ± 4.1 and 58.2 ± 2.8 during the Ensure test. After STEA, there was ~24% increase in % of normal waves, significantly different from the sham (6.0%) (P < .01). In sham or STEA, vagal activity was identical at baseline and after the Ensure. STEA induced a 3-fold increase in vagal activity compared with sham (P < .01). Ensure increased serum PP levels, and both treatments decreased the PP CONCLUSIONS: In IGP, STEA is not superior to Sham in decreasing nausea, but is more effective in improving gastric dysrhythmia.

Gastric per-oral endoscopic myotomy for refractory gastroparesis: a detailed description of the procedure, our experience, and review of the literature

BACKGROUND AND AIMS

Gastric per-oral endoscopic myotomy (G-POEM) was introduced four years ago as an investigational procedure for refractory gastroparesis. The safety and efficacy were currently evaluated. With our recent studies on G-POEM, we share our experience and knowledge through the discussion of a detailed description of the procedure and review of the literature. To our knowledge, this is the first systemic review on this new therapeutic endoscopic procedure.

METHODS

The indications and contraindications, various aspects of the procedure, and efficacy assessment are discussed based on our experience and current available data.

RESULTS

Preoperative preparation, detailed description of the procedure, post-procedural care, and results in the literature are presented. The procedure is safe and effective. 70-80% of patients have significant improvement in overall symptoms and quality of life in short-term (6 months) follow-up, as assessed by Gastric Cardinal Symptom Index and Short Form 36.

CONCLUSIONS

G-POEM is a feasible and effective procedure for refractory gastroparesis based on early and limited data. Well-designed prospective studies are expected to advance and evaluate this new procedure in the future.

Outcomes and quality-of-life assessment after gastric per-oral endoscopic pyloromyotomy (with video)

BACKGROUND AND AIM

Gastric per-oral endoscopic pyloromyotomy (GPOEM) is emerging as a promising option for the treatment of gastroparesis. This study assessed outcomes and quality of life after GPOEM for gastroparesis, performed in an endoscopy unit at a major tertiary referral center.

METHODS

We performed a retrospective review of patients who had undergone GPOEM from June 2015 to July 2016. Data were collected from electronic medical records and included patient demographics, endoscopy records, hospitalization records, clinic visits, and electronic messages. Scores for the Short Form 36 (SF36) and Gastroparesis Cardinal Symptom Index (GCSI) were obtained pre-procedure (16 patients), at 1 month (16 patients), at 6 months (13 patients), and at 12 months (6 patients) after the GPOEM procedure was performed.

RESULTS

Sixteen consecutive patients, 13 women and 3 men (mean age, 44.76 ± 14.8 years), who underwent GPOEM were enrolled. GPOEM was technically successful in all cases. Thirteen of 16 (81%) patients had a significant improvement in the mean GCSI after GPOEM: 3.40 ± 0.50 before the procedure (16 patients) to 1.48 ± 0.95 (P = .0001) at 1 month (16 patients), 1.36 ± 0.9 (P < .01) at 6 months (13 patients), and 1.46 ± 1.4 (P < .01) at 12 months (6 patients) follow-up. Mean duration of the procedure was 49.7 ± 22.1 minutes. Mean myotomy length was 2.94 ± 0.1 cm. Mean length of hospital stay was 2.46 ± 0.7 days. No adverse events occurred with GPOEM. The SF36 questionnaire demonstrated a significant improvement in quality of life in several domains that was sustained through 6-months' follow-up. Mean 4-hour gastric retention on gastric emptying scans decreased from 62.9% ± 24.3% to 17.6% ± 16.7% (P = .007) after GPOEM.

CONCLUSIONS

GPOEM results in improvement in the overall symptoms of gastroparesis measured by GCSI, objective assessment of improvement in gastric emptying, and improvement in multiple domains on validated quality-of-life inventories in SF36 over a follow-up period of 6 months.

Fluoroscopy-guided gastric peroral endoscopic pyloromyotomy (G-POEM): a more reliable and efficient method for treatment of refractory gastroparesis

INTRODUCTION

Prior studies show promising results of the gastric peroral endoscopic pyloromyotomy (G-POEM) procedure for treatment of refractory gastroparesis. One major technical challenge involved in this procedure is identifying the pyloric muscular ring (PMR). The aim of this study is to establish a reliable method for identification of the PMR during G-POEM.

METHODS

Fluoroscopy-guided G-POEM was performed by placing an endoclip at the 9 to 11'o clock position at the pylorus for identification of PMR. Conventional G-POEM was performed by observation of blue colored mucosa at the pylorus area as an indirect marker for PMR. The degree of the PMR identification was graded into well identified, identified, and not identified based on the appearance of the PMR. Procedure times were accurately documented. Gastroparesis cardinal symptoms index and gastric emptying scintigraphy were evaluated before and after the procedure.

RESULTS

Fourteen patients were studied, seven underwent fluoroscopy-guided G-POEM, and seven patients underwent conventional G-POEM. All procedures achieved technical success and no adverse events occurred. In the seven patients who underwent fluoroscopy-guided G-POEM, the PMR was well identified in four patients and identified in three patients. In the seven patients who underwent conventional G-POEM, the PMR was identified in four patients and not identified in three patients. The average time to complete the fluoroscopy-guided G-POEM was significantly shorter than that of the conventional G-POEM.

CONCLUSIONS

Fluoroscopy-guided G-POEM by placement of an endoclip at the pylorus was a reliable and safe method to direct the orientation of the submucosal tunnel, to facilitate the location of the PMR, and to shorten the procedure time.

Preoperative carbohydrate loading in the enhanced recovery pathway

The enhanced recovery pathway is an evidence-based surgical care pathway that includes preoperative, perioperative and postoperative care and results in fewer complications and a shorter length of stay in hospital. There are a variety of elements associated with this pathway and one is the use of a preoperative carbohydrate-loading drink. The consumption of this drink, which is specifically designed to be safely consumed a few hours before surgery, is discussed with a review of the literature on the topic.

Gastric peroral endoscopic pyloromyotomy (G-POEM) as a salvage therapy for refractory gastroparesis: a case series of different subtypes

BACKGROUND

Gastroparesis is a poorly understood, chronic, debilitating motility disorder with very limited medical therapeutic options. Gastric peroral endoscopic pyloromyotomy (G-POEM) is an emerging novel endoscopic technique as an incisionless pyloroplasty for refractory cases. Effective information of G-POEM on different types of gastroparesis is sparse.

METHODS

Cases of G-POEM using selective circular myotomy as a salvage therapy for refractory symptoms were retrospective studied. The G-POEM procedures were performed by a single expert endoscopist under a certain protocol. Gastroparesis Cardinal Symptoms Index (GCSI) and gastric emptying scintigraphy (GES) were evaluated before and after the procedure. Procedures related adverse event were also recorded.

KEY RESULTS

All procedures were successfully completed without complications. Each case in this series was different in demography and etiology of gastroparesis, namely postsurgical, postinfectious, and idiopathic gastroparesis in an elderly male and two young female adults. All cases were refractory to conventional treatment but demonstrated obvious success after G-POEM as a salvage therapy both clinically and on GES.

CONCLUSIONS & INFERENCES

G-POEM as a salvage therapy improves symptoms and gastric emptying in patients with different types of refractory gastroparesis. Our cases are also the firsts to show success of G-POEM in postinfectious gastroparesis and in elderly male patient. More data are needed to determine which subgroup of patients would benefit most from this novel procedure.

Pyloroplasty for Refractory Gastroparesis

Gastroparesis is a chronic gastric motility disorder in which the pathophysiology mimics a post-vagotomy state. Pyloroplasty is beginning to emerge as a successful drainage procedure for refractory gastroparesis. Here we report our experience using pyloroplasty in the surgical management of diabetic and nondiabetic gastroparesis. A retrospective study was performed of 46 patients undergoing pyloroplasty for refractory gastroparesis from January 2010 through December 2013. Gastric emptying scintigraphy and the Gastroparesis Cardinal Symptom Index were assessed pre-and postoperatively. Laparoscopic pyloroplasty was performed in 42 patients, open pyloroplasty in three, and one patient was converted from laparoscopic to open pyloroplasty. Studies were repeated during the six to 12 month postoperative interval. The postoperative gastric emptying scintigraphy improved in 90 per cent of patients and normalized in 60 per cent. Postoperative T½ was significantly reduced ( P = 0.001) as was four-hour retention ( P < 0.001). The Gastroparesis Cardinal Symptom Index showed statistically significant reduction in symptom severity for all nine categories ( P < 0.0005) as well as total symptom score ( P < 0.005). No patients developed dumping syndrome. Pyloroplasty is a highly effective therapy for refractory gastroparesis, offering significant reduction in symptom severity, improvement in quality of life, and acceleration of gastric emptying.

Guidance: The practical management of the gastrointestinal symptoms of pelvic radiation disease

BACKGROUND

A recent randomised trial suggested that an algorithmic approach to investigating and managing gastrointestinal symptoms of pelvic radiation disease (PRD) is beneficial and that specially trained nurses can manage patients as effectively as a gastroenterologist.

AIMS

The aim of the development and peer review of the guide was to make the algorithm used in the trial accessible to all levels of clinician.

METHODS

Experts who manage patients with PRD were asked to review the guide, rating each section for agreement with the recommended measures and suggesting amendments if necessary. Specific comments were discussed and incorporated as appropriate, and this process was repeated for a second round of review.

RESULTS

34 gastroenterologists, 10 nurses, 9 dietitians, 7 surgeons and 5 clinical oncologists participated in round one. Consensus (defined prospectively as 60% or more panellists selecting 'strongly agree' or 'agree') was reached for 27 of the original 28 sections in the guide, with a median of 75% of panellists agreeing with each section. 86% of panellists agreed that the guide was acceptable for publication or acceptable with minor revisions. 55 of the original 65 panellists participated in round two. 89% agreed it was acceptable for publication after the first revision. Further minor amendments were made in response to round two.

CONCLUSIONS

Development of the guide in response to feedback included ▸ improvement of occasional algorithmic steps ▸ a more user-friendly layout ▸ clearer timeframes for referral to other teams ▸ expansion of reference list ▸ addition of procedures to the appendix.

Gastric vagal motoneuron function is maintained following experimental spinal cord injury

BACKGROUND

Clinical reports indicate that spinal cord injury (SCI) initiates profound gastric dysfunction. Gastric reflexes involve stimulation of sensory vagal fibers, which engage brainstem circuits that modulate efferent output back to the stomach, thereby completing the vago-vagal reflex. Our recent studies in a rodent model of experimental high thoracic (T3-) SCI suggest that reduced vagal afferent sensitivity to gastrointestinal (GI) stimuli may be responsible for diminished gastric function. Nevertheless, derangements in efferent signals from the dorsal motor nucleus of the vagus (DMV) to the stomach may also account for reduced motility.

METHODS

We assessed the anatomical, neurophysiological, and functional integrity of gastric-projecting DMV neurons in T3-SCI rats using: (i) retrograde labeling of gastric-projecting DMV neurons; (ii) whole cell recordings from gastric-projecting neurons of the DMV; and, (iii) in vivo measurements of gastric contractions following unilateral microinjection of thyrotropin-releasing hormone (TRH) into the DMV.

KEY RESULTS

Immunohistochemical analysis of gastric-projecting DMV neurons demonstrated no difference between control and T3-SCI rats. Whole cell in vitro recordings showed no alteration in DMV membrane properties and the neuronal morphology of these same, neurobiotin-labeled, DMV neurons were unchanged after T3-SCI with regard to cell size and dendritic arborization. Central microinjection of TRH induced a significant facilitation of gastric contractions in both control and T3-SCI rats and there were no significant dose-dependent differences between groups.

CONCLUSIONS & INFERENCES

Our data suggest that the acute, 3 day to 1 week post-SCI, dysfunction of vagally mediated gastric reflexes do not include derangements in the efferent DMV motoneurons.

Blockade of p38 mitogen-activated protein kinase pathway ameliorates delayed gastric emptying in streptozotocin-induced diabetic rats

BACKGROUND AND AIM

Gastrointestinal dysfunction is one of the major complications of diabetes. The roles of inflammation in diabetes and its associated complications are increasingly recognized. p38 mitogen-activated protein kinase (MAPK) has been shown to be involved in the production of pro-inflammatory mediators. The aims of this study were to investigate the effects of SB203580, a specific p38 MAPK inhibitor, on delayed gastric emptying in diabetic rats and to elucidate its possible mechanism.

METHODS

SB203580 was administered in diabetic rats induced by intraperitoneal injection of streptozotocin. The gastric emptying rate of rats was measured by using phenol red solution, and blood glucose levels and body weights were observed. p38 MAPK activity and iNOS expression were assessed by Western blot analysis. The expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β were determined by enzyme-linked immunosorbent assay.

RESULTS

Gastric emptying was delayed significantly in diabetic rats and improved significantly with SB203580; high glucose significantly activated p38 MAPK and increased the expression of iNOS, TNF-α and IL-1β. The administration of SB203580 led to a significant decrease in the activation of p38 MAPK and the expression of iNOS, TNF-α and IL-1β.

CONCLUSIONS

Inflammation was associated with the development of delayed gastric emptying, and blockade of p38 MAPK pathway with SB203580 ameliorates delayed gastric emptying in diabetic rats, at least in part, by inhibiting the expression of iNOS, TNF-a and IL-1β. Therefore, p38MAPK may serve as a novel target for the therapy of diabetes-related gastrointestinal dysmotility.

Clinical features and severity of gastric emptying delay in Brazilian patients with gastroparesis

CONTEXT

Gastroparesis is defined by delayed gastric emptying without mechanical obstruction of the gastroduodenal junction, which has been increasingly investigated. Nevertheless, knowledge on the relationships between etiology, symptoms and degree of delayed gastric emptying is limited.

OBJECTIVES

The demographic, clinical and etiological features of Brazilian patients with gastroparesis were studied and the relationships between these findings and the severity of gastric emptying were determined.

METHOD

This is a retrospective study of medical records of 41 patients with symptoms suggestive of gastroparesis admitted between 1998 and 2011, who had evidence of abnormally delayed gastric emptying on abdominal scintigraphy. Cases with idiopathic gastroparesis were compared with those of patients with neurologic disorders or diabetes mellitus, in whom autonomic neuropathy is likely to occur.

RESULTS

The majority of the patients were women (75.6%) with a median age of 41 years and a long-term condition (median: 15 years). Twelve patients (29.3%) had a body mass index of less than 20 kg/m2. The most common presenting symptoms were dyspepsia (53.6%), nausea and vomiting (46.3%), weight loss (41.4%) and abdominal pain (24.3%). Regarding etiology, 16 patients had digestive disorders including idiopathic gastroparesis (n = 12), 12 had postoperative conditions, 11 had diseases of the nervous system, five had diabetes mellitus and in three cases gastroparesis was associated to a variety of conditions. In the majority of patients (65.8%) gastric emptying was severely delayed. There was no association between etiology of gastroparesis, type of presenting symptoms and the degree of delay in gastric emptying. Gastroparesis patients with proven (neurological conditions) or presumed (diabetes) nervous system involvements were significantly younger (P = 0.001), had more recent symptom onset (P = 0:03) and a trend towards more severe gastric empty (P = 0:06). There were no significant differences between this subgroup of patients and that comprising cases of idiopathic gastroparesis regarding any of the variables studied.

CONCLUSIONS

The demographic, clinical and etiological characteristics of Brazilian patients with gastroparesis are quite varied, but there is a predominance of women with long-standing symptoms and marked delay in gastric emptying. The type of presenting symptoms and the degree of delay in gastric emptying do not predict the etiology of gastroparesis. However, severely delayed gastric emptying in younger patients with recent symptom onset should raise the suspicion of impaired neural control of gastro-duodenal motility.

Therapeutic potential of spinal cord stimulation for gastrointestinal motility disorders: a preliminary rodent study

BACKGROUND

Spinal cord electrical stimulation (SCS) has been applied for the management of chronic pain. Most of studies have revealed a decrease in sympathetic activity with SCS. The aim of this study was to investigate the effects and mechanisms of SCS on gastrointestinal (GI) motility in healthy and diabetic rats.

METHODS

Male rats chronically implanted with a unipolar electrode at T9/T10 were studied. The study included four experiments to assess the effects of SCS on (1) gastric tone; (2) gastric emptying of liquids and intestinal transit; (3) gastric emptying of solids; and (4) sympathovagal balance in healthy rats and/or in Streptozotocin (STZ)-induced diabetic rat.

KEY RESULTS

(1) Spinal cord stimulation intensity dependently increased gastric tone in healthy rats. The gastric volume was 0.97 ± 0.15 mL at baseline, and decreased to 0.92 ± 0.16 mL with SCS of the 30% motor threshold (MT; p = 0.13 vs baseline), 0.86 ± 0.14 mL with 60% MT (p = 0.045 vs baseline), and 0.46 ± 0.19 mL with 90% MT (p = 0.0050 vs baseline). (2) Spinal cord stimulation increased gastric emptying of liquids by about 17% and accelerated small intestinal transit by about 20% in healthy rats (p < 0.001). (3) Spinal cord stimulation accelerated gastric emptying of solids by about 24% in healthy rats and by about 78% in diabetic rats. (4) Spinal cord stimulation decreased sympathetic activity (1.13 ± 0.18 vs 0.68 ± 0.09, p < 0.04) and sympathovagal balance (0.51 ± 0.036 vs 0.40 ± 0.029, p = 0.028).

CONCLUSIONS & INFERENCES

Spinal cord stimulation accelerates gastric emptying of liquids and solids, and intestinal transit, probably by inhibiting the sympathetic activity. Spinal cord stimulation may have a therapeutic potential for treating GI motility disorders.

Role of preoperative carbohydrate loading: a systematic review

INTRODUCTION

Surgical stress in the presence of fasting worsens the catabolic state, causes insulin resistance and may delay recovery. Carbohydrate rich drinks given preoperatively may ameliorate these deleterious effects. A systematic review was undertaken to analyse the effect of preoperative carbohydrate loading on insulin resistance, gastric emptying, gastric acidity, patient wellbeing, immunity and nutrition following surgery.

METHODS

All studies identified through PubMed until September 2011 were included. References were cross-checked to ensure capture of cited pertinent articles.

RESULTS

Overall, 17 randomised controlled trials with a total of 1,445 patients who met the inclusion criteria were identified. Preoperative carbohydrate drinks significantly improved insulin resistance and indices of patient comfort following surgery, especially hunger, thirst, malaise, anxiety and nausea. No definite conclusions could be made regarding preservation of muscle mass. Following ingestion of carbohydrate drinks, no adverse events such as apparent or proven aspiration during or after surgery were reported.

CONCLUSIONS

Administration of oral carbohydrate drinks before surgery is probably safe and may have a positive influence on a wide range of perioperative markers of clinical outcome. Further studies are required to determine its cost effectiveness.

Advancing gastric emptying studies: standardization and new parameters to assess gastric motility and function

For many years, gastric emptying (GE) studies were performed using various local protocols and different radiolabeled meals. This lack of standardization and normal values made the test results unreliable and difficult to compare from one site to another. A recent consensus has been published that now provides guidance and standardization on how to perform a radiolabeled solid-meal GE study. It is widely recognized, however, that simple measurement of total GE of a solid meal often does not provide an answer to the etiology of symptoms for a large number of patients who present with functional dyspepsia. Advances in our understanding of the different roles of the fundus and antrum and their complex interaction with the proximal small bowel and central nervous system have led to the development of new methods to study gastric motility. This review describes how a more comprehensive approach to studying GE is needed and how this will lead to better diagnosis and treatment for patients referred for GE studies.

Postinfectious gastroparesis: a case series of three adolescent females

Postinfectious gastroparesis (PIGP) is a subgroup of idiopathic gastroparesis rarely reported in adolescents. This study describes 3 adolescent females with severe PIGP, who each underwent extensive workup prior to referral to a pediatric gastroenterologist. PIGP may be an underrecognized disorder in pediatrics, particularly in adolescents, and if untreated, can lead to significant morbidity.

Risk of gastroparesis in subjects with type 1 and 2 diabetes in the general population

OBJECTIVES

In patients with diabetes mellitus (DM) and upper gastrointestinal symptoms, a diagnosis of diabetic gastroparesis is often considered, but population-based data on the epidemiology of diabetic gastroparesis are lacking. We aimed to estimate the frequency of and risk factors for gastroparesis among community subjects with DM.

METHODS

In this population-based, historical cohort study, the medical records linkage system of the Rochester Epidemiology Project was used to identify 227 Olmsted County, MN residents with type 1 DM in 1995, a random sample of 360 residents with type 2 DM, and an age- and sex-stratified random sample of 639 nondiabetic residents. Using defined diagnostic criteria, we estimated the subsequent risk of developing gastroparesis in each group through 2006. The risk in DM, compared with frequency-matched community controls, was assessed by Cox proportional hazards modeling.

RESULTS

The cumulative proportions developing gastroparesis over a 10-year time period were 5.2% in type 1 DM, 1.0% in type 2 DM, and 0.2% in controls. The age- and gender-adjusted hazard ratios (HRs) for gastroparesis (relative to controls) was 33 (95% confidence interval (CI): 4.0, 274) in type 1 DM and 7.5 (95% CI: 0.8, 68) in type 2 DM. The risk of gastroparesis in type 1 DM was significantly greater than in type 2 DM (HR: 4.4 (1.1, 17)). Heartburn (HR: 6.6 (1.7, 25)) at baseline was associated with diabetic gastroparesis in type 1 DM.

CONCLUSIONS

Gastroparesis is relatively uncommon in patients with DM, although an increased risk for gastroparesis was observed in type 1 DM.

Ghrelin, appetite and gastric electrical stimulation

Ghrelin is a peptide hormone produced mainly by the stomach and has widespread physiological functions including increase in appetite. The stimulation of the ghrelin system represents a potential therapeutic approach in various disorders characterized by deficient ghrelin signaling or by low appetite. This stimulation may be achieved via pharmacological targeting of the ghrelin receptor with synthetic ghrelin or ghrelin mimetics or via increased endogenous ghrelin production. Recently, it was demonstrated that gastric electrical stimulation (GES) with Enterra parameters results in increased ghrelin production in rats. Furthermore, recent data revealed putative role of ghrelin-reactive immunoglobulins in the modulation of the ghrelin signaling which can be also stimulated by GES. Here, we review the links between GES and ghrelin in existing GES experimental and clinical applications for treatment of gastroparesis, functional dyspepsia or obesity and discuss if GES can be proposed as a non-pharmacological approach to improve ghrelin secretion in several pathological conditions characterized by low appetite, such as anorexia nervosa or anorexia-cachexia syndrome.

Neostigmine-induced contraction and nitric oxide-induced relaxation of isolated ileum from STZ diabetic guinea pigs

Both delayed gastrointestinal transit and autonomic neuropathy have been documented in patients with diabetes mellitus. The mechanism of neostigmine, an agent that mimics release of acetylcholine from autonomic neurons by prokinetic agents, to contract smooth muscle, despite dysfunctional enteric neural pathways, was determined using isolated ilea from STZ-treated and control guinea pigs. Both bethanechol- and neostigmine-induced contractions were stronger in diabetic ileum. Bethanechol-induced contractions of control but not diabetic ileum were increased by low dose scopolamine suggesting reduced activation of presynaptic muscarinic autoreceptors in diabetic ileum. The muscarinic receptor antagonist 4-DAMP strongly, but the nicotinic receptor antagonist hexamethonium only weakly, reduced neostigmine-induced contractions of control and diabetic ilea. The amount of acetylcholine, inferred from tissue choline content, was increased in diabetic ileum. Nicotinic neural and noncholinergic postjunctional smooth muscle receptors contributed more strongly to neostigmine-induced contractions in diabetic than control ileum. Relaxation of diabetic ileum by exogenous nitric oxide generated from sodium nitroprusside was comparable to control ileum, but smooth muscle relaxation by l-arginine using neuronal nitric oxide synthase to generate nitric oxide was weaker in diabetic ileum with evidence for a role for inducible nitric oxide synthase. Despite autonomic neuropathy, neostigmine strongly contracted ileum from diabetic animals but by a different mechanism including stronger activation of postjunctional muscarinic receptors, greater synaptic acetylcholine, stronger activation of noncholinergic excitatory pathways, and weaker activation of inhibitory pathways. A selective medication targeting a specific neural pathway may more effectively treat disordered gastrointestinal transit in patients with diabetes mellitus.

Gastric relaxation induced by glucagon-like peptide-2 in mice fed a high-fat diet or fasted

Glucagon-like peptide-2 (GLP-2) is a nutrient-responsive gut hormone that increases the intestinal absorption. Exogenous GLP-2 also induces gastric fundus relaxation with possible implications for emptying rate or feeling of satiety. GLP-2 actions are mediated by GLP-2 receptor (GLP-2R), located on enteric neurons and myofibroblasts in murine gastrointestinal tract. Because it is not known whether changes in the endogenous GLP-2R levels occur in different nutritional states, we examined the GLP-2R gene and protein expression in gastric fundus from standard diet (STD)-fed, 12-h and 24-h fasted and re-fed, or high-fat diet (HFD)-fed mice and we analyzed the mechanical responses to exogenous GLP-2 in the stomach from different groups of animals. GLP-2 expression was examined using real-time reverse-transcription polymerase chain reaction and western blotting. The gastric mechanical activity from whole-organ was recorded in vitro as changes of intraluminal pressure. GLP-2R expression in fundic region from 12-h or 24-h fasted mice was reduced in comparison with STD-fed animals and returned to control values in re-fed mice, while it was increased in HFD-fed mice. The exogenous GLP-2 efficacy in inducing gastric relaxation, normalized to isoproterenol response, was decreased in stomach from fasted mice and it was increased in stomach from HFD-fed mice in comparison with STD-fed mice. In conclusion, the nutritional state influences GLP-2R expression in murine gastric preparations. The changes in the GLP-2R expression are associated with modifications of GLP-2 gastric relaxant efficacy. This could represent an adaptive response to reduced or increased nutrient intake.

Postgastrectomy nutrition

Gastric resection, whether partial or total gastrectomy, often results in nutrition-related complications including weight loss, diet intolerances, and micronutrient deficiencies. The physiology of normal and postgastrectomy digestion is the basis for most of the current diet recommendations after gastric surgery. A careful review reveals that there is not sufficient literature to support a standard postgastrectomy diet. Rather, individualized diet manipulation for symptom relief is recommended. This review highlights the physiology behind common postgastrectomy complications, provides guidelines for the medical and nutrition management of these complications, and presents a basic approach to postgastrectomy gastrointestinal symptoms.

Cellular changes in diabetic and idiopathic gastroparesis

BACKGROUND & AIMS

Cellular changes associated with diabetic and idiopathic gastroparesis are not well described. The aim of this study was to describe histologic abnormalities in gastroparesis and compare findings in idiopathic versus diabetic gastroparesis.

METHODS

Full-thickness gastric body biopsy specimens were obtained from 40 patients with gastroparesis (20 diabetic) and matched controls. Sections were stained for H&E and trichrome and immunolabeled with antibodies against protein gene product (PGP) 9.5, neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide, substance P, and tyrosine hydroxylase to quantify nerves, S100β for glia, Kit for interstitial cells of Cajal (ICC), CD45 and CD68 for immune cells, and smoothelin for smooth muscle cells. Tissue was also examined by transmission electron microscopy.

RESULTS

Histologic abnormalities were found in 83% of patients. The most common defects were loss of ICC with remaining ICC showing injury, an abnormal immune infiltrate containing macrophages, and decreased nerve fibers. On light microscopy, no significant differences were found between diabetic and idiopathic gastroparesis with the exception of nNOS expression, which was decreased in more patients with idiopathic gastroparesis (40%) compared with diabetic patients (20%) by visual grading. On electron microscopy, a markedly increased connective tissue stroma was present in both disorders.

CONCLUSIONS

This study suggests that on full-thickness biopsy specimens, cellular abnormalities are found in the majority of patients with gastroparesis. The most common findings were loss of Kit expression, suggesting loss of ICC, and an increase in CD45 and CD68 immunoreactivity. These findings suggest that examination of tissue can lead to valuable insights into the pathophysiology of these disorders and offer hope that new therapeutic targets can be found.

Gastric electrical stimulation on gastric motility in dogs

AIMS

  The aim of this study was to systematically evaluate and compare the effects of synchronized dual-pulse gastric electrical stimulation (SDPS) and conventional gastric electrical stimulation (CGES) on antral contractions, gastric tone, and autonomic functions.

METHODS

  Seven female hound dogs implanted with four pairs of electrodes on gastric serosa were studied in two separate experiments. The first experiment was designed to investigate the effects of SDPS/CGES on gastric tone and heart rate variations. The second experiment was performed to study the effects of SDPS/CGES on antral contractions.

RESULTS

  1) SDPS induced gastric antral contractions in the fasting state, whereas CGES at the intrinsic or a tachygastrial frequency had no effects on fasting antral contractions. 2) SDPS enhanced postprandial antral contractions impaired by glucagon; however, CGES at a tachygastrial frequency inhibited postprandial antral contractions. In addition, CGES at the intrinsic frequency of the stomach had no effects on postprandial antral contractions. 3) SDPS or CGES at the intrinsic frequency of the stomach had no effects on gastric tone, but CGES at a tachygastrial frequency reduced gastric tone. 4) SDPS excited vagal activity, but CGES at a tachygastrial frequency inhibited vagal activity.

CONCLUSIONS

  SDPS improves antral contractions but does not affect gastric tone and thus may have potential for treating gastric motility disorders. CGES at a tachygastrial frequency inhibits gastric tone and contractions and may be applicable for treating obesity. The excitatory or inhibitory effects of SDPS/CGES on gastric motility may be mediated via vagal pathway.

Management of diabetic gastroparesis

Symptoms suggestive of gastroparesis occur in 5% to 12% of patients with diabetes. Such a complication can affect both prognosis and management of the diabetes; therefore, practicing clinicians are challenged by the complex management of such cases. Gastroparesis is a disorder characterized by a delay in gastric emptying after a meal in the absence of a mechanical gastric outlet obstruction. This article is an evidence-based overview of current management strategies for diabetic gastroparesis. The cardinal symptoms of diabetic gastroparesis are nausea and vomiting. Gastroesophageal scintiscanning at 15-minute intervals for 4 hours after food intake is considered the gold standard for measuring gastric emptying. Retention of more than 10% of the meal after 4 hours is considered an abnormal result, for which a multidisciplinary management approach is required. Treatment should be tailored according to the severity of gastroparesis, and 25% to 68% of symptoms are controlled by prokinetic agents. Commonly prescribed prokinetics include metoclopramide, domperidone, and erythromycin. In addition, gastric electrical stimulation has been shown to improve symptoms, reduce hospitalizations, reduce the need for nutritional support, and improve quality of life in several open-label studies.

Advances in complete small-bowel examination by capsule endoscopy

Capsule endoscopy (CE) has a battery life of 8 h, during which time complete small-bowel examination can be achieved in most cases. However, in 10-30% of cases, the capsule cannot reach the ileocecal valve before the end of the life of the capsule's battery due to factors other than mechanical bowel obstruction. Incomplete examination of the entire small bowel leaves room for missing lesions. Some studies have shown that diabetes mellitus can lead to gastroparesis and increase gastric transit time (GTT), while history of abdominal surgery can increase small bowel transit time (SBTT). Therefore, these two factors can decrease the rate of complete small-bowel examination by CE. Purgative bowel cleansing can improve the detectability and image quality of CE, but has no significant impact on GTT, SBTT and CR. Prokinetic drugs, real-time CE, right lateral position, and chewing-gum are all under research for increasing CR. In future studies, emphasis should be placed in improving the diagnostic ability of CR and ensuring optimal intervention for patients with high risk factors for incomplete small-bowel examination.

Regional differences in neostigmine-induced contraction and relaxation of stomach from diabetic guinea pig

Delayed gastric emptying and autonomic neuropathy have been documented in patients with diabetes mellitus. Some medications used to treat delayed gastric emptying enhance release of acetylcholine from autonomic neurons to strengthen gastric contractions. Autonomic coordination among gastric regions may be altered in diabetes resulting in poor outcomes in response to prokinetic drugs. Fundus, antrum, and pylorus from STZ or control guinea pigs were treated with neostigmine to mimic release of acetylcholine from autonomic neurons by prokinetic agents. In diabetic animals, neostigmine-induced contractions were weaker in fundus and pylorus but similar in antrum. The muscarinic receptor antagonist 4-DAMP or the nicotinic receptor antagonist hexamethonium reduced neostigmine-induced contractions. Activation of presynaptic muscarinic receptors on nitrergic neurons was impaired in fundus and antrum from diabetic animals. Nerve-stimulated contractions and relaxations, number of nNOS myenteric neurons, and tissue choline content were reduced in fundus from diabetic animals. Despite reduced number of myenteric neurons, tissue choline content was increased in antrum from diabetic animals. Since cholinergic motility of each gastric region was affected differently by diabetes, prokinetic drugs that nondiscriminately enhance acetylcholine release from autonomic neurons may not effectively normalize delayed gastric emptying in patients with diabetes and more selective medications may be warranted.

Advantages of azithromycin over erythromycin in improving the gastric emptying half-time in adult patients with gastroparesis

Background/Aims

Current therapy for gastroparesis with prokinetic agents is limited by options and side effects. One macrolide, erythromycin (ERY), is associated with possible sudden cardiac death from QT prolongation due to P450 iso-enzyme inhibition. An alternative, azithromycin (AZI), lacks P450 inhibition. We compared the effect on gastric emptying half-times (t½) between AZI and ERY in patients diagnosed with gastroparesis by gastric emptying scintigraphy.

Methods

Patients stopped medications known to affect gastric emptying prior to the study, and then ingested 1 scrambled egg meal labeled with 18.5-37 MBq of technetium-99m sulfur colloid followed by continuous imaging for 120 minutes, at 1 minute per frame. A simple linear fit was applied to the rate of gastric emptying, and gastric emptying t½ was calculated (normal = 45-90 minutes). At 75-80 minutes, if the stomach had clearly not emptied, patients were given either ERY (n = 60) or AZI (n = 60) 250 mg IV and a new post-treatment gastric emptying t½ was calculated.

Results

Comparison of gastric emptying t½ showed a similar positive effect (mean gastric emptying t½ for AZI = 10.4 ± 7.2 minutes; mean gastric emptying t½ for ERY = 11.9 ± 8.4 minutes; p = 0.30).

Conclusions

AZI is equivalent to ERY in accelerating the gastric emptying of adult patients with gastroparesis. Given the longer duration of action, better side effect profile and lack of P450 interaction for AZI as compared with ERY, further research should evaluate the long term effectiveness and safety of AZI as a gastroparesis treatment.

Diabetic gastroparesis: Therapeutic options

Gastroparesis is a condition characterized by delayed gastric emptying and the most common known underlying cause is diabetes mellitus. Symptoms include nausea, vomiting, abdominal fullness, and early satiety, which impact to varying degrees on the patient's quality of life. Symptoms and deficits do not necessarily relate to each other, hence despite significant abnormalities in gastric emptying, some individuals have only minimal symptoms and, conversely, severe symptoms do not always relate to measures of gastric emptying. Prokinetic agents such as metoclopramide, domperidone, and erythromycin enhance gastric motility and have remained the mainstay of treatment for several decades, despite unwanted side effects and numerous drug interactions. Mechanical therapies such as endoscopic pyloric botulinum toxin injection, gastric electrical stimulation, and gastrostomy or jejunostomy are used in intractable diabetic gastroparesis (DG), refractory to prokinetic therapies. Mitemcinal and TZP-101 are novel investigational motilin receptor and ghrelin agonists, respectively, and show promise in the treatment of DG. The aim of this review is to provide an update on prokinetic and mechanical therapies in the treatment of DG.