American Gastroenterological Association technical review on the diagnosis and treatment of gastroparesis

Laparoscopically Implanted Gastric Pacemaker after Kidney-Pancreas Transplantation: Treatment of Morbid Obesity and Diabetic Gastroparesis

Combined kidney-pancreas transplantation is the treatment of choice for end-stage diabetic nephropathy. Weight gain post-transplant increases the risk for post-transplant complications and death due to cardiovascular events. Gastric pacemakers have been used for therapy of diabetic gastropathy and for the treatment of moderate morbid obesity. We report a patient who experienced significant weight gain following successful kidney-pancreas transplantation and was thereafter successfully treated for diabetic gastroparesis and morbid obesity by use of a laparoscopically implanted gastric pacemaker.

Diabetes induces sex-dependent changes in neuronal nitric oxide synthase dimerization and function in the rat gastric antrum

Diabetic gastroparesis is a disorder that predominantly affects women. However, the biological basis of this sex bias remains completely unknown. In this study we tested the hypothesis that a component of this effect may be mediated by the nitrergic inhibitory system of the enteric nervous system. Age-matched male and female Sprague-Dawley rats were studied 8 or 12 wk after streptozotocin (55 mg/kg body wt ip)-induced sustained hyperglycemia and compared with controls. Solid gastric emptying (GE) studies were performed in all the groups. Changes in gastric antrum neuronal nitric oxide synthase (nNOS) mRNA and protein levels were analyzed by real-time PCR and Western immunoblotting, respectively. nNOS dimerization studies were performed using low-temperature SDS-PAGE. In vitro nitrergic relaxation (area under curve/mg tissue wt) was studied after the application of electric field stimulation in an organ bath. Changes in intragastric pressure (mmHg.s) in freely moving rats in the presence or absence of N(G)-nitro-l-arginine methyl ester (nitric oxide synthase inhibitor) were examined by an ambulatory telemetric method. After diabetes induction, GE is delayed in both male and female rats. However, diabetic females exhibited significant delayed GE than in diabetic males. Compared with male controls, gastric nNOS expression and nitrergic relaxation were substantially elevated in healthy female control rats, accompanied by significantly reduced intragastric pressure. The active dimeric form and dimer-to-monomer ratio of nNOSalpha were also higher in healthy females compared with male rats (P < 0.05). Diabetic females, but not males, showed significant (P < 0.05) impairment in both gastric nNOSalpha dimerization and nitrergic relaxation, accompanied by an increase in intragastric pressure. Our data provide evidence that females may have a greater dependency on the nitrergic mechanisms in health. Furthermore, diabetes seems to affect the nitrergic system to a greater extent in females than in males. Together, these changes may account for the greater vulnerability of females to diabetic gastric dysfunction.

Rapid gastric emptying is more common than gastroparesis in patients with autonomic dysfunction

OBJECTIVES

Autonomic dysfunction is associated with a wide variety of gastrointestinal symptoms. It is unclear how many patients with autonomic dysfunction have slow or rapid gastric emptying. The aim of this study was to determine the prevalence of rapid and delayed solid phase gastric emptying in patients with autonomic dysfunction referred for evaluation of gastrointestinal symptoms and the association of emptying rate with clinical symptoms.

METHODS

Retrospective review of all patients with autonomic dysfunction who had a gastric emptying test from January, 1996 to March, 2005. Demographic data, clinical symptoms, composite autonomic scoring scale (CASS) score, and gastric emptying parameters were analyzed.

RESULTS

Sixty-one subjects (women 49, age 42 [16-74] yr) with autonomic dysfunction were reviewed. Patients had mild-to-moderate (mean CASS score 3) autonomic dysfunction. Twenty-seven, 17, and 17 patients had rapid, normal, and delayed gastric emptying t(1/2), respectively. In addition, 10 patients had initially rapid emptying in phase 1, with subsequent slowing in phase 2 to produce an overall normal or delayed t(1/2). There was no difference in demographic data or CASS score among the three groups. More patients with initial or overall rapid emptying had diarrhea (70%) compared to patients with normal (33%) or delayed (33%) emptying (P= 0.018).

CONCLUSIONS

Unexpectedly, more patients with autonomic dysfunction have rapid rather than delayed gastric emptying. The presence of diarrhea in patients with autonomic symptoms should prompt consideration for the presence of rapid gastric emptying. Conversely, the finding of rapid gastric emptying in patients with gastrointestinal symptoms should prompt consideration for the presence of underlying autonomic dysfunction.

Laparoscopic Insertion of Gastric Electrodes for Electrical Stimulation

Gastric electrical stimulation can provide symptomatic relief for patients with refractory gastroparesis. Traditionally, these wires are placed through a midline laparotomy. This paper describes and illustrates, in detail, the laparoscopic technique for successful implantation. Thirty-one consecutive patients from October 2003 to March 2005 underwent laparoscopic insertion of gastric stimulating wires for gastroparesis. Twenty-six patients were female. Four laparoscopic ports were used to insert a pair of electrodes. Anterior, cephalad retraction of the gastric wall is critical for accurate seromuscular placement of gastric leads. Intraoperative endoscopy was used to verify the seromuscular placement of the leads. Both leads were secured to a subcutaneous generator and electrical parameters were immediately established in the operating room. Patient demographics, operative details, and postoperative morbidities were recorded. All procedures were completed laparoscopically. The mean operative time was 114.4 +/- 20.9 minutes (range, 95-140). No perioperative mortality occurred. Two patients developed cellulitis at the generator site postoperatively and oral antibiotics were prescribed for one week postoperatively. No hardware was removed. Two patients had their generators repositioned due to pain at the pocket site. Gastric electrical stimulation is a novel treatment modality for patients with refractory gastroparesis and can be accomplished safely via laparoscopy. Laparoscopic insertion is successful even in patients with prior surgery and intact gastrointestinal tubes. Long-term follow-up and the current prospective multicenter trial continue to assess the efficacy of this treatment modality.

Percutaneous implantation of gastric electrodes - a novel technique applied in animals and in patients

Temporary electrodes implanted under general anaesthesia, or via an oral or percutaneous endoscopic gastrostomy route have been used for testing of gastric electrical stimulation (GES). We have developed a principle for percutaneous electrode implantation. Leads were constructed so that the tip could be anchored to the gastric submucosa under gastroscopic control. Acute experiments were performed in anaesthetized pigs. Three patients referred for nausea and/or vomiting and non-established indications for GES (chronic intestinal pseudo-obstruction, functional dyspepsia without gastroparesis) were evaluated. Electrode function was tested by recording and stimulation techniques. In the pigs, a slow-wave (SW) rhythm (3 min(-1)) was recorded with decrease in frequency at the end of the experiments. In the patients, implantation time from start of gastroscopy to end of electrode placement was 12-20 min. Electrode distance varied from 12 to 45 mm. Gastric electromyography showed a regular SW rhythm of about 3 min(-1). Antral pressure waves had intervals being multiples of the SW-to-SW time. With temporary GES for 7-9 days, weekly frequency of the referral symptoms decreased >80% in two patients and 33% in one patient. Temporary percutaneous gastric leads can easily be implanted and may be used for testing of GES and study of gastric electrophysiology.

Gastroparesis secondary to a demyelinating disease: a case series

Background

Gastroparesis has a number of etiologies. The main ones are secondary to a complication from diabetes mellitus, related to post vagotomy or post gastric surgical resections, or idiopathic when the etiology is unclear. Gastroparesis secondary to a demyelinating disease of the brain is unusual.

Case presentation

A 22-year-old woman was referred for acute onset of intractable nausea and vomiting. She also had cerebellar deficits, dysphagia and paresthesias. Magnetic resonance imaging (MRI) of the brain revealed an isolated area of demyelination in the medullary region. Another 24-year-old woman had a similar presentation with right hemiplegia and MRI of the brain revealed a distal medullary region. Both these patients had an abnormal gastric emptying test. Gastroparesis and neurological deficits improved with intravenous corticosteroids. While the former patient has had no further recurrences, the latter patient developed multiple sclerosis within three months of presentation.

Conclusion

A demyelinating disease is a rare cause gastropareis, but should be suspected when symptoms of gastroparesis are associated with neurological deficits. MRI might help in the diagnosis and intravenous coriticosteroids can address the underlying disease process and improve gastric emptying, especially when used early during the course of the disease.

Aliskiren exhibits similar pharmacokinetics in healthy volunteers and patients with type 2 diabetes mellitus

BACKGROUND

The renin system is an attractive target for antihypertensive therapy in patients with diabetes mellitus. However, diabetes is associated with changes in gastrointestinal, renal and hepatic function that may affect the absorption and disposition of oral drugs. This study compared the pharmacokinetics and pharmacodynamics of the orally active direct renin inhibitor, aliskiren, in healthy volunteers and patients with type 2 diabetes.

METHODS

This was an open-label study conducted in 30 patients with type 2 diabetes and 30 healthy volunteers matched for age, bodyweight and race. Following a 10-hour fast, all participants received a single oral dose of aliskiren 300mg. Blood samples were taken at frequent intervals for 96 hours post-dose for determination of plasma concentrations of aliskiren (using a high-performance liquid chromatography-tandem mass spectroscopy method). Plasma renin activity (PRA) and renin concentration (RC) were also measured for 24 hours after dosing.

RESULTS

Aliskiren exhibited similar pharmacokinetics in patients with type 2 diabetes and healthy volunteers. Exposure to aliskiren was slightly higher in patients with type 2 diabetes compared with healthy volunteers (mean area under the plasma concentration-time curve from 0 to 24 hours 1859 vs 1642 ng . h/mL; maximum observed plasma drug concentration 394 vs 348 ng/mL), while apparent clearance corrected for bioavailability was slightly lower (205 vs 234 L/h) and elimination half-life slightly longer (44 vs 39.9 hours), but there were no statistically significant differences for any pharmacokinetic parameters. There was no significant correlation between glycaemic control (% glycosylated haemoglobin) and any of the measured pharmacokinetic parameters in patients with type 2 diabetes. Aliskiren caused sustained suppression of PRA for at least 24 hours after dosing despite increasing RC; there were no major differences in the pharmacodynamic effects of aliskiren between patients with type 2 diabetes and healthy volunteers. Aliskiren was well tolerated in both patient groups, with no clinically significant changes in laboratory values and a low risk of adverse events.

CONCLUSION

Aliskiren showed a similar pharmacokinetic profile in healthy volunteers and patients with type 2 diabetes, and administration of a single oral 300 mg dose of aliskiren was well tolerated by both patients and healthy volunteers. The pharmacodynamic effects of aliskiren were also similar in healthy volunteers and diabetic patients, with sustained inhibition of renin system activity observed for at least 24 hours after dosing.

Gastric electrical stimulation in medically refractory nausea and vomiting

INTRODUCTION

High-frequency gastric electrical stimulation is a new therapeutic option to improve refractory nausea and vomiting, in gastroparetic patients. Its effects on gastric emptying are, however, inconstant and limited. Therefore, we have hypothesized that high-frequency gastric electrical stimulation could be also effective in patients suffering from refractory vomiting and nausea with normal gastric emptying, and we have compared the symptomatic efficacy of high-frequency gastric electrical stimulation between patients with delayed and normal gastric emptying.

PATIENTS AND METHODS

Fifteen patients with chronic, severe and medically resistant nausea and vomiting were included in the study. Gastric emptying was delayed in eight patients (Group 1) and normal in seven patients (Group 2). At inclusion and at 6 months after the start of the stimulation, symptoms (nausea and vomiting, bloating, regurgitations, abdominal pain and appetite) and quality of life were prospectively evaluated using the Gastrointestinal Quality of Life Index score whereas gastric emptying was assessed by scintigraphy and/or octanoic acid breath test.

RESULTS

Age, sex, symptoms and quality of life were not different at baseline between the two groups. At 6 months, Gastrointestinal Quality of Life Index and nausea/vomiting scores had significantly improved in both groups. Other symptoms (bloating, regurgitations, abdominal pain and appetite) had improved at 6 months in Group 1 but not in Group 2. Six months after the start of stimulation, gastric emptying was normal in 4/8 Group 1 patients and 5/7 Group 2 patients but was not significantly different from that calculated before the implantation of the stimulator.

CONCLUSION

Our results suggest that high-frequency gastric electrical stimulation could be an effective therapy for treating chronic, severe vomiting and nausea whether gastric emptying is delayed or not.

Systematic review: applications and future of gastric electrical stimulation

BACKGROUND

Over the past 20 years, gastric electrical stimulation has received increasing attention among researchers and clinicians.

AIM

To give a systematic review on the effects, mechanisms and applications of gastric electrical stimulation.

METHODS

Medline was used to identify the articles to be included in this review. Key words used for the search included gastric electrical stimulation, gastric pacing, electrical stimulation, stomach, gastrointestinal motility, central nervous system, gastroparesis, nausea and vomiting; obesity and weight loss. Combinational uses of these keywords were made to identify relevant articles. Most of the articles included in this review ranged from 1985 to 2006.

RESULTS

Based on the general search, the review was structured as follows: (i) peripheral and central effects and mechanisms of gastric electrical stimulation; (ii) clinical applications of gastric electrical stimulation for gastroparesis and obesity and (iii) future development of gastric electrical stimulation.

CONCLUSIONS

Great progress has been made during the past decades. Gastric electrical stimulation has been shown to be effective in normalizing gastric dysrhythmia, accelerating gastric emptying and improving nausea and vomiting. Implantable device has been made available for treating gastroparesis as well as obesity. However, development of a new device and controlled clinical studies are required to further prove clinical efficacy of gastric electrical stimulation.

Update on gastrointestinal scintigraphy

Nuclear medicine offers a variety of studies for evaluating motility throughout the gastrointestinal tract. Gastric emptying remains the "gold standard" for studying gastric motor function, but its application in most centers remains limited to measuring only total gastric emptying in spite of data that show assessment of both fundal and antal function is of clinical value for evaluating patients with dyspepsia. Similarly, newer methods to study small bowel and colon transit have not gained widespread use. This review summarizes the state-of-the-art of prior established and newer scintigraphic studies with an emphasis on their clinical applications.

Gastric electrical stimulation for intractable vomiting in patients with chronic intestinal pseudoobstruction

Gastric electrical stimulation (GES) is effective for medically refractory nausea and vomiting in patients with idiopathic or diabetic gastroparesis (DGP). We studied whether GES has similar effects in chronic intestinal pseudoobstruction (CIP). Patients referred for chronic small bowel (SB) motor dysfunction requiring parenteral nutrition and having a weekly vomiting frequency (WVF) >/=7 refractory to prokinetics and antiemetics were included. Patients were implanted for high-frequency GES 12 stimuli min(-1), laparoscopy being the first-line implantation procedure. Results were compared with those obtained in 11 DGP patients. Three patients with familial CIP and one patient with postsurgical CIP fulfilled the criteria. Gastric emptying was delayed in two and was normal in two patients. SB transit time was markedly delayed. Laparoscopy was used in three patients, one patient required laparotomy. During GES, WVF decreased from 24 (mean) before GES to 6.9 at 12 months and 7.5 at last visit. Vomiting reduction was 50-90% at last visit. For the DGP patients, WVF decreased from 23 before GES to 3.5 at 12 months and 3.5 (P < 0.01) at last visit. In patients with CIP and medically refractory vomiting, GES seems to have an anti-vomiting effect comparable to that seen in patients with severe DGP. GES should be considered as a therapeutic option for these patients.

Influence of intrapyloric botulinum toxin injection on gastric emptying and meal-related symptoms in gastroparesis patients

BACKGROUND

Recent observations in limited numbers of patients suggest a potential benefit of intrapyloric injection of botulinum toxin in the treatment of gastroparesis.

AIM

To characterize the effect of botulinum toxin on solid and liquid gastric emptying and on meal-related symptoms.

METHODS

In 20 gastroparesis patients (17 women, mean age 37 +/- 3 years, three diabetic and 17 idiopathic), gastric emptying for solids and liquids was measured before and one month after intrapyloric botulinum toxin 4 x 25 units. Before the meal and at 15-min intervals up to 240 min postprandially, the patient graded the intensity of six gastroparesis symptoms, and a meal-related severity score was obtained by adding all intensities. Data (mean +/- S.E.M.) were compared using paired Student's t-test.

RESULTS

Treatment with botulinum toxin significantly enhanced solid (t(1/2) 132 +/- 16 vs. 204 +/- 35 min, P < 0.05) but not liquid (92 +/- 10 vs. 104 +/- 11 min, N.S.) emptying. This was accompanied by a significant decrease in cumulative meal-related symptom score (73.5 +/- 16.3 vs. 103 +/- 17.1 baseline, P = 0.01) as well as individual severity scores for postprandial fullness, bloating, nausea and belching (all P < 0.001, two-way anova).

CONCLUSIONS

Botulinum toxin improves solid but not liquid gastric emptying in gastroparesis, and this is accompanied by significant improvement of several meal-related symptoms.

Update on Gastroparesis

Gastroparesis is a manifestation of diabetic autonomic neuropathy. Gastrointestinal autonomic neuropathy contributes to morbidity, mortality, reduced quality of life, and increased healthcare costs of a patient with diabetes mellitus. Complications from gastroparesis include ketoacidosis, infection, and bezoar formation. The gold standard for the diagnosis of gastroparesis is a gastric emptying study. Other tests and procedures may also be performed to eliminate other causes of the symptoms. In general, treatment involves dietary and lifestyle adjustment as well as pharmacological interventions. Gastric electrical stimulation has recently emerged as an effective strategy in the management of these patients. Research is evolving in this area to include the use of botulinum toxin to control symptoms of gastroparesis. Patients with gastroparesis can be frustrated with the symptoms they experience, the intensive treatment regimens they must follow, as well as the medical procedures they undergo during the course of their treatment. Quality of life is an important factor to consider when caring for and supporting these patients. This article will provide an overview of gastroparesis and the latest treatments available to improve gastric motility and prevent further complications.

Gastroparesis: clinical update

Gastroparesis refers to chronically abnormal gastric motility characterized by symptoms suggestive of mechanical obstruction and delayed gastric emptying in the absence of mechanical obstruction. It may be idiopathic or attributable to neuropathic or myopathic abnormalities, such as diabetes mellitus, postvagotomy, postviral infection, and scleroderma. Dietary and behavioral modification, prokinetic drugs, and surgical interventions have been used in managing patients with gastroparesis. Although mild gastroparesis is usually well managed with these treatment options, severe gastroparesis may be very difficult to control and may require referral to a specialist center if symptoms are intractable despite pharmacological therapy and dietetic support. New advances in drug therapy, botulinum toxin injection, and gastric electrical stimulation techniques have been introduced and might provide new hope to patients with refractory gastroparesis. This article critically reviews the advances in the field from the perspective of the clinician.

Treatment of gastroparesis: a multidisciplinary clinical review

This clinical review on the treatment of patients with gastroparesis is a consensus document developed by the American Motility Society Task Force on Gastroparesis. It is a multidisciplinary effort with input from gastroenterologists and other specialists who are involved in the care of patients with gastroparesis. To provide practical guidelines for treatment, this document covers results of published research studies in the literature and areas developed by consensus agreement where clinical research trials remain lacking in the field of gastroparesis.

Drug Insight: from disturbed motility to disordered movement—a review of the clinical benefits and medicolegal risks of metoclopramide

Metoclopramide, the only drug approved by the FDA for treatment of diabetic gastroparesis, but used off-label for a variety of other gastrointestinal indications, has many potentially troublesome adverse neurologic effects, particularly movement disorders. In this article, we comprehensively review the indications and side effects of metoclopramide, and describe some common pitfalls and strategies to minimize the medicolegal risks to the prescribing physician. Metoclopramide accounts for nearly a third of all drug-induced movement disorders, a common reason for a malpractice suit. The entire spectrum of drug-induced movement disorders, ranging from subtle to life-threatening, can ensue from its use; akathisia and dystonia are generally seen early in the course of metoclopramide-induced movement disorders, whereas tardive dyskinesia and parkinsonism seem to be more prevalent in chronic users. Female sex, age and diabetes are the major risk factors for metoclopramide-induced movement disorders. It is therefore incumbent on gastroenterologists and other prescribing physicians to become familiar with the adverse neurologic effects associated with the use of metoclopramide, and to take appropriate preventive and defensive measures.

Reduced stem cell factor links smooth myopathy and loss of interstitial cells of cajal in murine diabetic gastroparesis

BACKGROUND & AIMS

Diabetic gastroparesis involves neuropathy, myopathy, and depletion of interstitial cells of Cajal (ICC), which may cause dysrhythmias and impaired neural control. Most murine gastric ICC depend on stem cell factor (SCF) signaling but can also be maintained with insulin or insulin-like growth factor-I (IGF-I). We investigated whether SCF could mediate the actions of insulin and IGF-I.

METHODS

Expression of insulin receptor, IGF-I receptor, and SCF was studied in gastric muscles and purified ICC by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The effects of insulin/IGF-I deficiency on SCF, ICC, smooth muscle, and neurons were investigated in nonobese diabetic mice and organotypic cultures by immunohistochemistry, microarrays, and/or quantitative RT-PCR. ICC in organotypic cultures were also studied after immunoneutralization of endogenous SCF.

RESULTS

Insulin and IGF-I receptors were detected in smooth-muscle cells and myenteric neurons but not in ICC. Cell-surface expression of SCF was only found in smooth-muscle cells. ICC depletion in diabetes was accompanied by smooth-muscle atrophy and reduced SCF, whereas neuron-specific gene expression remained unchanged. In organotypic cultures, prevention of ICC loss by insulin or IGF-I was paralleled by rescue of smooth-muscle cells and SCF expression but not of myenteric neurons. Immunoneutralization of endogenous SCF caused ICC depletion closely resembling that elicited by insulin/IGF-I deficiency.

CONCLUSIONS

Reduced insulin/IGF-I signaling in diabetes may lead to ICC depletion and its consequences by causing smooth-muscle atrophy and reduced SCF production. Thus, myopathy may play a more central role in diabetic gastroenteropathies than previously recognized.

Electrogastrography in pediatric functional dyspepsia: relationship to gastric emptying and symptom severity

OBJECTIVES

The aims of this study were to determine the electrogastrographic patterns in children with functional dyspepsia and to investigate the correlations among electrogastrogram (EGG), gastric emptying (GE), and pain severity.

METHODS

We studied 30 children (19 F; mean age 11.4 years) with functional dyspepsia. Electrogastrography was performed for 30 minutes fasting and for 1 hour during a GE test after ingestion of an isotope-labeled solid meal. The percent emptying was measured every 10 minutes for 1 hour after the meal. The dominant frequency of the EGG, the change in the postprandial peak power (deltaP), and percent dysrhythmia during each recording session were calculated. Specific symptoms were graded from 0 (none) to 4 (severe) by the patient.

RESULTS

Of 30 patients, 14 (47%) had slow GE, and 15 (50%) had abnormal EGG (dysrhythmia > or = 30% or deltaP < 0). GE was slow in 73% of patients with an abnormal EGG but was slow in only 20% of patients with normal EGG (P = 0.009). GE was negatively correlated with fasting bradygastria (r = -0.383, P = 0.04). Abdominal pain was the most severe dyspeptic symptom, both during fasting and after the meal. Patients with an abnormal EGG had an increased mean pain severity score (3.5 +/- 0.2 vs. 2.5 +/- 0.2, P = 0.002).

CONCLUSIONS

Sixty percent of functional dyspepsia subjects had either slow GE or abnormal EGG. Patients with abnormal EGG were more likely to have slow GE. EGG abnormalities were associated with more severe postprandial pain and should be considered a possible mechanism for dyspeptic symptoms.

Gastric electrical stimulation in gastroparesis: where do we stand?

Gastroparesis is a chronic disabling condition of impaired gastric motility that results in decreased quality of life. Currently available medical therapy consists of prokinetic and/or antiemetic therapy, dietary modifications, and nutritional supplementation. For patients with medication-resistant gastroparesis a non-pharmacological therapy, gastric electric stimulation, has evolved over the last decade. Based on the frequency of the electrical stimulus, gastric electric stimulation can be classified into low- and high-frequency gastric electric stimulation. The first method aims to normalize gastric dysrhythmia and entrain gastric slow waves and accelerates gastric emptying, whereas high-frequency gastric electric stimulation is unable to restore normal gastric emptying, but nevertheless stunningly reduces symptoms, such as nausea and vomiting, re-establishes quality of life, nutritional state in all patients, and metabolic control in patients with diabetic gastroparesis. Gastric electric stimulation presents a new possibility in the treatment of gastroparesis.

Promotility medications--now and in the future

Gastrointestinal promotility drugs stimulate smooth muscle contractions to enhance gastric emptying and small and large bowel transit. Currently available drug classes with prokinetic properties include antidopaminergic agents, serotonergic agents, and motilin-receptor agonists. Due to moderate prokinetic effects, poor symptomatic responses and the presence of adverse effects, there is a clear need for new classes of prokinetics. Several newer prokinetic drugs and drug classes are currently under evaluation. Selecting candidate agents and designing the appropriate therapeutic trials is hampered by the lack of insight in the pathophysiology of motility-related symptoms. As gastrointestinal motor disorders are chronic, relapsing, and remitting disorders, it seems desirable that studies with candidate prokinetic drugs establish a long-term efficacy and not only short-term effects on gastrointestinal functions.

Intrapyloric injection of botulinum toxin a for the treatment of persistent gastroparesis following successful pancreas transplantation

Intrapyloric injection of botulinum toxin A (BoTx) successfully improved symptoms in idiopathic and diabetic gastroparesis (DGP) refractory to medical treatment. Therefore, we used it in three pancreas transplant patients done in our institution during the last 18 months. They had severe, persistent DGP despite successful pancreas transplantation. They received 100 units of BoTx during the first injection. The clinical effect became evident within 2 weeks after the treatment, and lasted for an average of 29 weeks (range 14-44 weeks). The patients' subjective evaluation showed improvement of their symptoms and quality of life following BoTx. Patients 2 and 3 had recurrent symptoms at 44 and 24 weeks, respectively, after the first injection; they required a second dose of 90 and 80 units, respectively. They are doing well at 3 months follow-up. Intrapyloric injection of BoTx is safe and efficient. It should be considered for treating residual DGP following successful pancreas transplantation.

Nutrition and motility disorders

The purpose of this article is to give an overview of the relation between feeding and gastrointestinal symptoms and complaints, and to review different motility disorders that have implications for food intake. We also report the consequences for nutrition state and the evidence-based principles of dietary modification in patients with motility disorders.

Gastric motor function and emptying in the right decubitus and seated body position as assessed by magnetic resonance imaging

PURPOSE

To determine the effect of the right decubitus lying body position (RP) on relevant parameters of human gastric motor function in healthy volunteers.

MATERIALS AND METHODS

Postprandial gastric function after ingestion of a solid/liquid meal (150 g/150 mL) was assessed over 90 minutes in volunteers in the RP and seated position (SP). Ten healthy volunteers were imaged using two MRI systems that differed in architecture and field strength. Stomach and intragastric air volume, intragastric meal distribution, gastric emptying, and gastric peristalsis were compared between the RP and SP.

RESULTS

Body position did not affect gastric relaxation (RP, 372 mL vs. SP, 384 mL) and initial gastric volumes (stomach: RP, 458 mL vs. SP, 462 mL; meal: RP, 377 mL vs. SP, 399 mL; intragastric air: RP, 110 mL vs. SP, 98 mL). Postprandial stomach volume and gastric activity (RP and SP, 3.1 minute(-1)) were also similar. Meal emptying showed different characteristics, resulting in a significant but small difference in meal volume of -43 mL at t = 90 minutes (P < 0.05).

CONCLUSION

Gastric MRI in RP is feasible for clinical research assessing gastric motor function. The subtle difference in meal emptying may be induced by posture-dependent vagal activity. This study confirms that MRI is a highly sensitive imaging technique for assessing gastrointestinal function in humans.

Funktionelle Magnetresonanzbildgebung des Verdauungstrakts

Magnetic resonance imaging (MRI) is a versatile medical imaging tool for which several new applications have been developed. Beside its broad clinical use for the detection of anatomical structures and pathologies MRI has been successfully applied for the non-invasive imaging of human organ functions, including the brain and the cardiovascular system. The use of MRI for the assessment and analysis of gastrointestinal (GI) function is a new approach that is currently performed in only a few research sites. Several characteristics make MRI an ideal technique for the direct assessment of GI physiology: MRI acquires high resolution images with excellent soft tissue contrast, it does not expose subjects to ionizing radiation, is non-invasive, and the acquisition and analysis of the images can be independently verified. In this article we summarize recent developments of MRI techniques in GI research. We will also discuss the advantages and limitations of MRI for this purpose in relation to established medical imaging tools and investigations.

Neural stem cell transplantation in the stomach rescues gastric function in neuronal nitric oxide synthase-deficient mice

BACKGROUND & AIMS

Nitric oxide is a major inhibitory neurotransmitter in the enteric nervous system. Loss or dysfunction of nitrinergic neurons is associated with serious disruptions of motility, intractable symptoms, and long-term suffering. The aim of this study was to evaluate the effect of intrapyloric transplantation of neural stem cells (NSCs) on gastric emptying and pyloric function in nNOS-/- mice, a well-established genetic model of gastroparesis.

METHODS

NSCs were isolated from embryonic mice transgenically engineered to express green fluorescent protein and transplanted into the pylorus of nNOS-/- mice. Grafted cells were visualized in pyloric sections and further characterized by immunofluorescence staining. One week posttransplantation, gastric emptying to a non-nutrient meal was measured using the phenol red method and pyloric function was assessed by measuring the relaxation of pyloric strips in an organ bath in response to electrical field stimulation (EFS) under nonadrenergic, noncholinergic conditions.

RESULTS

One week following implantation, grafted NSCs differentiated into neurons and expressed neuronal nitric oxide synthase. Gastric emptying was significantly increased in mice that received NSCs as compared with vehicle-injected controls (49.67% vs 35.09%; P < .01 by Student t test). EFS-induced relaxation of pyloric strips was also significantly increased (P < .01 by 2-way analysis of variance). The nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester and the neuronal blocker tetrodotoxin blocked the EFS-induced relaxation, indicating that the observed effect is NO mediated and neuronally derived.

CONCLUSIONS

Our results support the potential of NSC transplantation as a viable therapeutic option for neuroenteric disorders.

Factors that affect gastric passage of video capsule

BACKGROUND

Gastric retention and delayed gastric emptying of the video capsule are major limitations. We retrospectively studied gastric transit time, gastric retention, and completeness of capsule endoscopy (CE) in relation to the conditions in which it was performed.

METHODS

From May 2002 to September 2004, CE was performed in 190 patients (92 men; mean age, 58.4 years, range 16-91 years). Patients were stratified according to the way CE was performed (hospital day setting, outpatient, or ongoing hospitalization), and the recordings were analyzed to measure gastric retention, gastric transit time, and the completeness of the examinations.

RESULTS

CE examination was performed in a hospital day setting in 100 patients, in an outpatient setting in 61, and during hospitalization in 29. Gastric retention of the capsule occurred in 8 of 190 patients (4.2%) (5 women, 3 men; mean age, 37.9 years). Gastric retention occurred during hospitalization in 7/29 (24.1%) and in hospital day setting in one of 100. Ongoing hospitalization was statistically associated with an increased risk of gastric capsule retention (p < 0.0001). The cecum was reached in 165/190 (87%), and ongoing hospitalization was associated with a lower rate of complete examinations (p < 0.001). Small-bowel transit time was similar, regardless of the circumstances of CE performance.

CONCLUSIONS

Ongoing hospitalization is a major cause of gastric retention and incomplete examination by CE. Therefore, CE performance during ongoing hospitalization may require the use of a prokinetic agent.

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 normal and pathologic gastric sensory and motor function.

RECENT FINDINGS

Several novel tests have been developed to study gastric sensitivity and meal-induced accommodation, including scintigraphic analysis of meal distribution within the stomach, single photon emission computed tomography of gastric volumes, and nutrient or water challenge tests. Several studies have reported on the occurrence of delayed gastric emptying in functional dyspepsia and in gastroparesis, but the correlation with symptoms was generally poor. The pathways and neurotransmitter involved in gastric hypersensitivity are progressively being unraveled. Several studies have confirmed and focused on increased symptom occurrence after nutrient challenge in functional dyspepsia. The role of the proximal stomach in the control of food intake and the stomach as a target in the treatment of obesity are areas of intense research. Studies have reported on pharmacologic approaches as well as electric stimulation in the treatment of gastric sensorimotor dysfunction.

SUMMARY

Progress in our understanding of normal and abnormal gastric sensory and motor function may lead to new or improved treatment modalities. Areas of major advances are the study of meal-induced symptoms in functional dyspepsia, unraveling of the role of the stomach in the control of food intake, and the use of gastric electric stimulation in gastroparesis and in obesity.

An unusual electrocardiogram artifact: what is its source?

A diabetic female presented with nausea and vomiting. Her electrocardiogram showed sinus rhythm with two artifactual spikes, not synchronized with the cardiac rhythm. The patient had an implanted gastric electrical stimulation system for treating her diabetic gastroparesis. Recent DC shock for ventricular fibrillation during coronary angiography caused malfunction of the gastric pacemaker.

Gastric Motility, Gastroparesis, and Gastric Stimulation

Gastroparesis is the most common disorder of gastric motility. It is frequently overlooked in clinical practice because the symptoms of gastroparesis are nonspecific. This article reviews normal and abnormal gastric motility, discusses the etiology and pathogenesis of gastroparesis, and provides an overview on new treatment options for gastroparesis, including gastric stimulation.

New management approaches for gastroparesis

Management of patients with gastroparesis is challenging. Although the syndrome has multiple causes and knowledge of the pathophysiology and natural history is far from complete, a number of common management principles can be applied. The relatively poor correlation between upper-gastrointestinal symptoms and disordered gastric emptying represents a major difficulty in the therapeutic approach, and evidence to support the efficacy of current management strategies is often suboptimal, especially in relation to long-term therapy. In this review, the common causes and pathophysiology of gastroparesis are summarized, the diagnostic approach considered, and the evidence to support medical and surgical therapies reviewed. These therapies include currently available prokinetic drugs, novel medical therapies, and the promising technique of gastric electrical stimulation.

Some interactions between gastrointestinal function and fluid and electrolyte homeostasis

PURPOSE OF REVIEW

The gastrointestinal tract plays an important role in the maintenance of fluid and electrolyte balance, and its diseases cause disturbances in that balance. Conversely, fluid and electrolyte disorders may disturb gastrointestinal function. The purpose of this review is to highlight some recent literature describing these interactions against a background of fluid and electrolyte physiology in normal and disease states.

RECENT FINDINGS

Gastrointestinal disease is the most common cause of fluid and electrolyte disturbance, and this can usually be corrected by the oral route, although parenteral replacement is sometimes required. The use of self-administered subcutaneous fluid and electrolyte administration at home is described. Reduced microcirculatory perfusion as a result of hypovolaemia or a rise in blood viscosity after packed cell transfusion may precipitate gut necrosis, particularly during enteral feeding. Positive salt and water balance postoperatively of as little as 3 l impairs gastrointestinal function and increases complications. Other states of salt and water retention may have similar effects, although further research is needed to define this.

SUMMARY

The role of the gastrointestinal tract in controlling fluid and electrolyte balance is underestimated. Conversely, the effect of fluid and electrolyte imbalance on gastrointestinal function is apparent, but requires more research.