Multicenter, Phase 1, Open Prospective Trial of Gastric Electrical Stimulation for the Treatment of Obesity: First-in-Human Results with a Novel Implantable System

Background and Aims

To assess safety of the Exilis™ gastric electrical stimulation (GES) system and to investigate whether the settings can be adjusted for comfortable chronic use in subjects with morbid obesity. Gastric emptying and motility and meal intake were evaluated.

Method

In a multicenter, phase 1, open prospective cohort study, 20 morbidly obese subjects (17 female, mean BMI of 40.8 ± 0.7 kg/m²) were implanted with the Exilis™ system. Amplitude of the Exilis™ system was individually set during titration visits. Subjects underwent two blinded baseline test days (GES ON vs. OFF), after which long-term, monthly follow-up continued for up to 52 weeks.

Results

The procedure was safe, and electrical stimulation was well tolerated and comfortable in all subjects. No significant differences in gastric emptying halftime (203 ± 16 vs. 212 ± 14 min, p > 0.05), food intake (713 ± 68 vs. 799 ± 69 kcal, p > 0.05), insulin AUC (2448 ± 347 vs. 2186 ± 204, p > 0.05), and glucose AUC (41 ± 2 vs.41 ± 2, p > 0.05) were found between GES ON and OFF. At week 4, 13, and 26, a significant (p < 0.01) reduction in weight loss was observed but not at week 52. At this time point, the mean excess weight loss (EWL) was 14.2 ± 4.5%.

Conclusion

Gastric electrical stimulation with the Exilis™ system can be considered as safe. No significant effect on food intake, gastric emptying, or gastric motility was observed. The reduction in weight loss with Exilis™ GES was significant but short lasting. Further electrophysiological research is needed to gain more insight in optimal stimulation parameters and lead localization.

Gastroesophageal Reflux and Microaspiration in Lung Transplant Recipients: The Utility of a Single Esophageal Manometry and pH Probe Monitoring Study

BACKGROUND

Gastroesophageal reflux (GER) in recipients of lung transplant (LTX) is associated with chronic allograft rejection, presumably via microaspiration that damages airway epithelium. Most LTX programs perform a single post-LTX esophageal study to evaluate for GER; the efficacy of this test is unclear.

METHODS

Patients with 1 year of post-LTX follow-up, including routine bronchoscopies with bronchoalveolar lavage fluid (BALF) samples as well as high-resolution esophageal manometry and pH probe monitoring (HREMpH), were evaluated. BALF samples were analyzed with competitive enzyme-linked immunosorbent assay to detect bile salts, which are indicative of aspiration. These results were compared to results of HREMpH studies post LTX.

RESULTS

Ninety BALF samples were analyzed for bile salts and acted as disease positive for this evaluation. Of the 13 HREMpH cases, 8 were positive for GER, but only 3 were positive for bile salts via assay. Of the 5 HREMpH-negative cases, 2 experienced aspiration. A solitary HREMpH study had 60.0% sensitivity and 37.5% specificity with positive and negative likelihood ratios: 0.96 and 1.07, respectively.

CONCLUSION

Microaspiration appears to be an intermittent phenomenon, and HREMpH screening poorly correlates with BALF evidence of aspiration; which may not be adequate. As aspiration detection is crucial in this population, further analysis is warranted.

Intravenous immunoglobulin in drug and device refractory patients with the symptoms of gastroparesis-an open-label study

BACKGROUND

Gastroparesis is a complex clinical entity; many aspects of which remain unknown. Although most patients have idiopathic, diabetic, or postsurgical gastroparesis, many are thought to have measurable neuromuscular abnormalities. Immunotherapy has recently been utilized to treat suspected autoimmune gastrointestinal dysmotility.

METHODS

Fourteen patients with symptoms of gastroparesis (Gp) who were refractory to drug/device were selected from 443 Gp patients from 2013 to 2015 who were treated at the University of Louisville motility center. All patients underwent a structural and psychiatric evaluation along with detailed psychological and behavioral examination to rule out eating disorders. We performed detailed neuromuscular evaluation and all 14 patients received at least 12 weeks of intravenous immunoglobulin (400 mg/kg infusion weekly). Response was defined subjectively (symptomatic improvement) using standardized IDIOM score system.

KEY RESULTS

All 14 patients had serological evidence and/or tissue evidence of immunological abnormality. Post-IVIG therapy, there was a significant improvement in symptoms scores for nausea, vomiting, early satiety, and abdominal pain.

CONCLUSIONS AND INFERENCES

Although limited by the absence of placebo group, the data illustrate the role of autoimmunity and neuromuscular evaluation in patients with gastroparesis and support the utility of a diagnostic trial of immunotherapy in an effort to improve therapeutic outcomes for such patients.

Relating gastric scintigraphy and symptoms to motility capsule transit and pressure findings in suspected gastroparesis

BACKGROUND

Wireless motility capsule (WMC) findings are incompletely defined in suspected gastroparesis. We aimed to characterize regional WMC transit and contractility in relation to scintigraphy, etiology, and symptoms in patients undergoing gastric emptying testing.

METHODS

A total of 209 patients with gastroparesis symptoms at NIDDK Gastroparesis Consortium centers underwent gastric scintigraphy and WMCs on separate days to measure regional transit and contractility. Validated questionnaires quantified symptoms.

KEY RESULTS

Solid scintigraphy and liquid scintigraphy were delayed in 68.8% and 34.8% of patients; WMC gastric emptying times (GET) were delayed in 40.3% and showed 52.8% agreement with scintigraphy; 15.5% and 33.5% had delayed small bowel (SBTT) and colon transit (CTT) times. Transit was delayed in ≥2 regions in 23.3%. Rapid transit was rarely observed. Diabetics had slower GET but more rapid SBTT versus idiopathics (P ≤ .02). GET delays related to greater scintigraphic retention, slower SBTT, and fewer gastric contractions (P ≤ .04). Overall gastroparesis symptoms and nausea/vomiting, early satiety/fullness, bloating/distention, and upper abdominal pain subscores showed no relation to WMC transit. Upper and lower abdominal pain scores (P ≤ .03) were greater with increased colon contractions. Constipation correlated with slower CTT and higher colon contractions (P = .03). Diarrhea scores were higher with delayed SBTT and CTT (P ≤ .04).

CONCLUSIONS & INFERENCES

Wireless motility capsules define gastric emptying delays similar but not identical to scintigraphy that are more severe in diabetics and relate to reduced gastric contractility. Extragastric transit delays occur in >40% with suspected gastroparesis. Gastroparesis symptoms show little association with WMC profiles, although lower symptoms relate to small bowel or colon abnormalities.

Relationships between gastric slow wave frequency, velocity, and extracellular amplitude studied by a joint experimental-theoretical approach

BACKGROUND

Gastric slow wave dysrhythmias are accompanied by deviations in frequency, velocity, and extracellular amplitude, but the inherent association between these parameters in normal activity still requires clarification. This study quantified these associations using a joint experimental-theoretical approach.

METHODS

Gastric pacing was conducted in pigs with simultaneous high-resolution slow wave mapping (32-256 electrodes; 4-7.6 mm spacing). Relationships between period, velocity, and amplitude were quantified and correlated for each wavefront. Human data from two existing mapping control cohorts were analyzed to extract and correlate these same parameters. A validated biophysically based ICC model was also applied in silico to quantify velocity-period relationships during entrainment simulations and velocity-amplitude relationships from membrane potential equations.

KEY RESULTS

Porcine pacing studies identified positive correlations for velocity-period (0.13 mm s^-1 per 1 s, r² =.63, P<.001) and amplitude-velocity (74 μV per 1 mm s^-1 , r² =.21, P=.002). In humans, positive correlations were also quantified for velocity-period (corpus: 0.11 mm s^-1 per 1 s, r² =.16, P<.001; antrum: 0.23 mm s^-1 per 1 s, r² =.55; P<.001), and amplitude-velocity (94 μV per 1 mm s^-1 , r² =.56; P<.001). Entrainment simulations matched the experimental velocity-period relationships and demonstrated dependence on the slow wave recovery phase. Simulated membrane potential relationships were close to these experimental results (100 μV per 1 mm s^-1 ).

CONCLUSIONS AND INFERENCES

These data quantify the relationships between slow wave frequency, velocity, and extracellular amplitude. The results from both human and porcine studies were in keeping with biophysical models, demonstrating concordance with ICC biophysics. These relationships are important in the regulation of gastric motility and will help to guide interpretations of dysrhythmias.

Diabetic and idiopathic gastroparesis is associated with loss of CD206-positive macrophages in the gastric antrum

BACKGROUND

Animal studies have increasingly highlighted the role of macrophages in the development of delayed gastric emptying. However, their role in the pathophysiology of human gastroparesis is unclear. Our aim was to determine changes in macrophages and other cell types in the gastric antrum muscularis propria of patients with diabetic and idiopathic gastroparesis.

METHODS

Full thickness gastric antrum biopsies were obtained from patients enrolled in the Gastroparesis Clinical Research Consortium (11 diabetic, 6 idiopathic) and 5 controls. Immunolabeling and quantitative assessment was done for interstitial cells of Cajal (ICC) (Kit), enteric nerves protein gene product 9.5, neuronal nitric oxide synthase, vasoactive intestinal peptide, substance P, tyrosine hydroxylase), overall immune cells (CD45) and anti-inflammatory macrophages (CD206). Gastric emptying was assessed using nuclear medicine scintigraphy and symptom severity using the Gastroparesis Cardinal Symptom Index.

RESULTS

Both diabetic and idiopathic gastroparesis patients showed loss of ICC as compared to controls (Mean [standard error of mean]/hpf: diabetic, 2.28 [0.16]; idiopathic, 2.53 [0.47]; controls, 6.05 [0.62]; P=.004). Overall immune cell population (CD45) was unchanged but there was a loss of anti-inflammatory macrophages (CD206) in circular muscle (diabetic, 3.87 [0.32]; idiopathic, 4.16 [0.52]; controls, 6.59 [1.09]; P=.04) and myenteric plexus (diabetic, 3.83 [0.27]; idiopathic, 3.59 [0.68]; controls, 7.46 [0.51]; P=.004). There was correlation between the number of ICC and CD206-positive cells (r=.55, P=.008). Enteric nerves (PGP9.5) were unchanged: diabetic, 33.64 (3.45); idiopathic, 41.26 (6.40); controls, 46.80 (6.04).

CONCLUSION

Loss of antral CD206-positive anti-inflammatory macrophages is a key feature in human gastroparesis and it is associates with ICC loss.

Gastric dysmotility and low serum vitamin D levels in patients with gastroparesis

Nutritional abnormalities are common in patients with gastroparesis (Gp), a disorder that may affect gastric motility and may delay emptying. The aim of this work was to identify relationships between serum nutrition markers including 25-OH vitamin D and gastric motility measures in Gp patients. We enrolled 59 consecutive gastric motility clinic patients (48 females, 11 males; mean age 44 years; 42 idiopathic; 17 diabetes mellitus) with Gp symptoms. The 25-OH vitamin D levels, for most patients slightly above the lower limit of normal (96.98 nmol/l ± 60.99), were lowest in diabetic range (DM) (75.68 nmol/l ± 34.22) vs. idiopathic (ID) (105.03 nmol/l ± 67.08) gastroparesis patients. First hour GET: one unit increase in 25-OH vitamin D level was associated 0.11% improvement (95% CI -0.22, 0.01 p=0.056) in gastric motility in all patients; this association, although marked in ID Gp patients, (-0.13, CI -0.25, -0.01 p=0.034), was not seen in DM Gp, (0.2, CI -0.45, 0.87, p=0.525). Fourth hour GET: Every unit increase of 25-OH vitamin D was associated with significant improvement in all patients, ( 0.11% CI -0.23, 0.01, p=0.053), and some weak improvement in ID group, (0.11% -0.24, 0.01, p=0.076) and absent in patients with DM (0.03, CI -0.66, 0.72, p=0.932). It is concluded that 25-OH vitamin D levels may influence gastric emptying. Underlying mechanisms for this observation might include the impact of 25-OH vitamin D on the health of the enteric nervous system. 25-OH vitamin D contributions to enteric nerve functions should be explored, particularly where autonomic nervous system comorbidities exist.

Clinical-histological associations in gastroparesis: results from the Gastroparesis Clinical Research Consortium

BACKGROUND

Cellular changes associated with diabetic (DG) and idiopathic gastroparesis (IG) have recently been described from patients enrolled in the Gastroparesis Clinical Research Consortium. The association of these cellular changes with gastroparesis symptoms and gastric emptying is unknown. The aim of this study was to relate cellular changes to symptoms and gastric emptying in patients with gastroparesis.

METHODS

Earlier, using full thickness gastric body biopsies from 20 DG, 20 IG, and 20 matched controls, we found decreased interstitial cells of Cajal (ICC) and enteric nerves and an increase in immune cells in both DG and IG. Here, demographic, symptoms [gastroparesis cardinal symptom index score (GCSI)], and gastric emptying were related to cellular alterations using Pearson's correlation coefficients.

KEY RESULTS

Interstitial cells of Cajal counts inversely correlated with 4 h gastric retention in DG but not in IG (r = -0.6, P = 0.008, DG, r = 0.2, P = 0.4, IG). There was also a significant correlation between loss of ICC and enteric nerves in DG but not in IG (r = 0.5, P = 0.03 for DG, r = 0.3, P = 0.16, IG). Idiopathic gastroparesis with a myenteric immune infiltrate scored higher on the average GCSI (3.6 ± 0.7 vs 2.7 ± 0.9, P = 0.05) and nausea score (3.8 ± 0.9 vs 2.6 ± 1.0, P = 0.02) as compared to those without an infiltrate.

CONCLUSIONS & INFERENCES

In DG, loss of ICC is associated with delayed gastric emptying. Interstitial cells of Cajal or enteric nerve loss did not correlate with symptom severity. Overall clinical severity and nausea in IG is associated with a myenteric immune infiltrate. Thus, full thickness gastric biopsies can help define specific cellular abnormalities in gastroparesis, some of which are associated with physiological and clinical characteristics of gastroparesis.

Gastroparesis and functional dyspepsia: excerpts from the AGA/ANMS meeting

BACKGROUND

Despite the relatively high prevalence of gastroparesis and functional dyspepsia, the aetiology and pathophysiology of these disorders remain incompletely understood. Similarly, the diagnostic and treatment options for these two disorders are relatively limited despite recent advances in our understanding of both disorders.

PURPOSE

This manuscript reviews the advances in the understanding of the epidemiology, pathophysiology, diagnosis, and treatment of gastroparesis and functional dyspepsia as discussed at a recent conference sponsored by the American Gastroenterological Association (AGA) and the American Neurogastroenterology and Motility Society (ANMS). Particular focus is placed on discussing unmet needs and areas for future research.

Cyclic vomiting syndrome in adults

Cyclic vomiting syndrome (CVS) was initially described in children but can occur in all age groups. Cyclic vomiting syndrome is increasingly recognized in adults. However, the lack of awareness of CVS in adults has led to small numbers of diagnosed patients and a paucity of published data on the causes, diagnosis and management of CVS in adults. This article is a state-of-knowledge overview on CVS in adults and is intended to provide a framework for management and further investigations into CVS in adults.

An energy algorithm improves symptoms in some patients with gastroparesis and treated with gastric electrical stimulation

Gastric electrical stimulation (GES) is effective to improve symptoms of nausea and vomiting in most patients, but very little is known about the effect of varying stimulation parameters. We analysed stimulation parameters in a pilot study of 22 patients (12 idiopathic, four diabetic and four postsurgical) with drug-refractory gastroparesis who did not respond optimally to initial settings. Patients underwent high-frequency/low energy GES using identical initial stimulation parameters: 5 mA of current, 330 micros pulse width, 14 Hz for 0.1 s on and 5.0 s off. Due to lack on optimal response, 22 patients underwent alteration of an algorithm using stimulation parameters. At follow-up (mean of 4.3 years) a dose-response relationship for charge, power and energy were compared with baseline for the whole group and for each diagnostic subgroup by anova data are reported as mean +/- SE. Based on the mean of individual dose-response curves, differences in data are charge, current per pulse and energy per pulse were noted for the whole group at follow up vs baseline. The subgroup of patients with postsurgical gastroparesis required the most energy using the algorithm. In conclusion, an algorithmic approach to identify optimal stimulation parameters in GES for individual patients is associated with symptom improvement. Also, certain subgroups appear to have different energy parameters. Based on this preliminary data, the use of an algorithm for some patients with GES is feasible and may have potential for clinical application. A randomized-controlled trial of different stimulation parameters for GES seems warranted.

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.

Postinfectious gastroparesis related to autonomic failure: a case report

BACKGROUND AND AIM

Severe dysautonomia may be secondary to viral infections, resulting in impaired autoimmune, cardiovascular, urinary and digestive dysfunction. Herein, we present a case of a 31-year-old white female patient who had severe gastroparesis related to autonomic failure following an episode of acute gastroenteritis. This seems to be the first report providing thorough assessment of the enteric and autonomic nervous system by analysis of full-thickness small intestinal biopsies, cardiovagal testing and autopsy.

HOSPITAL COURSE

This patient affected by a severe gastroparesis was treated with antiemetics, prokinetics, analgesics and gastric electrical stimulation to control symptoms. Nutritional support was made using jejunal feeding tube and, in the final stage of disease, with total parenteral nutrition. Autonomic studies revealed minimal heart rate variability and a disordered Valsalva manoeuvre although the enteric nervous system and the smooth muscle layer showed a normal appearance. Hospital courses were complicated by episodes of bacteraemia and fungemia. Serum antiphospholipid antibodies were noted but despite anticoagulation, she developed a pulmonary embolism and shortly thereafter the patient died. Autopsy revealed acute haemorrhagic Candida pneumonia with left main pulmonary artery thrombus. Sympathetic chain analysis revealed decreased myelinated axons with vacuolar degeneration and patchy inflammation consistent with Guillain-Barre syndrome. The evaluation of the enteric nervous system in the stomach and small bowel revealed no evidence of enteric neuropathy or myopathy.

CONCLUSION

A Guillain-Barre-like disease with gastroparesis following acute gastroenteritis is supported by physiological and autonomic studies with histological findings.

Is gastric electrical stimulation superior to standard pharmacologic therapy in improving GI symptoms, healthcare resources, and long-term health care benefits?

CONTEXT

Severe upper gastrointestinal (GI) motor disorders, including gastroparesis (GP), can consume significant health care resources. Many patients are refractory to traditional drug therapy.

OBJECTIVE

To compare symptoms, healthcare resource utilization and costs in two groups of patients with the symptoms of GP: those treated via gastric electrical stimulation (GES) and those treated with traditional pharmacological agents in an intensive outpatient program (MED).

DESIGN

A long-term comparison of patients with devices (n = 9) vs intensive medical therapy (n = 9).

SETTING AND PATIENTS

A total of 18 eligible patients with the symptoms of GP reported for 1-year baseline and long-term treatment for 3 years.

INTERVENTIONS

Patients with the symptoms of GP were treated by a GES or intensive medical therapy (MED).

MAIN OUTCOME MEASURES

GP Symptoms, healthcare resource utilization using investigator-derived independent outcome measure score (IDIOMS) and total hospital (inpatient and outpatient) billing costs.

RESULTS

Gastrointestinal symptoms were significantly different from baseline (F = 3.03, P < 0.017) with GP patients treated via GES showing more sustained improvement over 36 months than those treated via MED. Healthcare resource usage, measured via the IDIOMS, significantly improved at 12, 24 and 36 month follow-up for GES patients (F = 10.49, P < 0.001), compared with patients receiving medical therapy, who demonstrated further deterioration. GP patients treated via GES also proved superior to medical therapy at 24 and 36 months with regard to decreased costs (F = 4.85, P < 0.001). Within group comparisons indicated significantly reduced hospital days for both patient groups; however, no statistical differences were noted between groups in terms of hospital days. Three of nine patients in the MED group died primarily from i.v. access related problems; none of the GES patients died.

CONCLUSION

We conclude that GES is more effective in improving long-term GI symptoms and costs, and decreasing use of healthcare resources than intensive medical therapy, in this sample of patients with the symptoms of GP followed for 3 years. Certain patients with GP form a high-risk group in terms of costs, quality of life, morbidity and mortality.

Assessment of gastric electrical activity and autonomic function among diabetic and nondiabetic patients with symptoms of gastroesophageal reflux

Gastroesophageal reflux disease (GERD) may present differently in patients with diabetes mellitus (DM) than in nondiabetics (NDM). We compared three tests in two patient groups with GERD symptoms: a DM group (n = 10) and a NDM group (n = 13). The tests were 24-hr esophageal pH, autonomic function testing (AFT), and electrogastrography (EGG). Analysis of the 23 patients revealed the DM group had normal 24-hr pH values (9 of 10 patients, mean pH 3.1 +/- 1.7), while NDM displayed abnormal pH values (9 of 13 patients, mean pH 21.2 +/- 5.9). AFT results were abnormal in DM (demonstrating cholinergic/ adrenergic dysfunction), but normal in NDM. EGG values were abnormal in both groups (mean 3.31 +/- 0.1 in each). We conclude that in GERD-symptomatic patients, those with DM frequently have normal 24-hr pH, but abnormal autonomic functioning, in contrast to NDM, who have abnormal 24-hr pH but normal autonomic function. Both groups had identically abnormal mean EGG values.

Sequential group trial to determine gastrointestinal site of absorption and systemic exposure of azathioprine

Azathioprine (AZA) is used in the treatment of patients with refractory inflammatory bowel disease; however, its use is limited because of systemic toxicity associated with long-term use. Ileocecal delivery of AZA might be advantageous if local intestinal therapeutic effects could be provided with decreased systemic side effects. Decreased cecal systemic absorption would allow higher dosages of AZA to be administered. A two-phase study was performed to compare the systemic exposure of AZA and 6-mercaptopurine (6-MP) following administration of AZA into the stomach, jejunum, and cecum and to compare the systemic exposure to AZA and 6-MP following administration of three different dosages of AZA into the cecum. In phase I, six healthy male volunteers received three 50 mg sequential doses of AZA via an oral tube directly placed into the stomach, jejunum, and cecum, respectively. In phase II, six healthy male volunteers received three different dosages (50, 300, 600 mg of AZA) into the cecum. Plasma concentrations of AZA and 6-MP at various times were quantified and area under the plasma concentration-time curve (AUC) and mean residence time (MRT) were determined. No significant differences in the AUC of AZA were seen at the different sites. The AUC of 6-MP following administration of AZA into the jejunum (67.0 +/- 30.1 ng x hr/ml) was higher compared to the stomach (39.9 +/- 38.1 ng/hr/ml) and cecum (29.2 +/- 10.9 ng x hr/ml). Jejunal absorption was 68% higher than absorption from the stomach and 129% higher than that of the cecum. Gastric absorption was 27% higher than that of the cecum. Increased dosages given into the cecum resulted in increased AUCs of AZA and 6-MP. The AUCs of AZA following 50, 300, and 600 mg dosages were 16.9 +/- 7.4, 52.3 +/- 67.2, and 132 +/- 151 ng x hr/ml, respectively, and the AUCs of 6-MP were 22.2 +/- 14.9, 63.4 +/- 50.6, and 104 +/- 115 ng x hr/ml, respectively. Systemic exposure to 6-MP is reduced following administration of AZA into the cecum, most likely secondary to reduced absorption of 6-MP from the colon. Higher dosages of AZA presented to the cecum do result in increased systemic absorption, but may still allow more drug to be administered with less toxicity than the same dose received orally.

Assessment of gastric emptying using a low fat meal: establishment of international control values

OBJECTIVE

The diagnosis of gastroparesis implies delayed gastric emptying. The diagnostic gold standard is scintigraphy, but techniques and measured endpoints vary widely among institutions. In this study, a simplified scintigraphic measurement of gastric emptying was compared to conventional gastric scintigraphic techniques and normal gastric emptying values defined in healthy subjects.

METHODS

In 123 volunteers (aged 19-73 yr, 60 women and 63 men) from 11 centers, scintigraphy was used to assess gastric emptying of a 99Tc-labeled low fat meal (egg substitute) and percent intragastric residual contents 60, 120, and 240 min after completion of the meal. In 42 subjects, additional measurements were taken every 10 min for 1 h. In 20 subjects, gastric emptying of a 99Tc-labeled liver meal was compared with that of the 99Tc-labeled low fat meal.

RESULTS

Median values (95th percentile) for percent gastric retention at 60, 120, and 240 min were 69% (90%), 24% (60%) and 1.2% (10%) respectively. A power exponential model yielded similar emptying curves and estimated T50 when using images only taken at 1, 2 and 4 h, or with imaging taken every 10 min. Gastric emptying was initially more rapid in men but was comparable in men and women at 4 h; it was faster in older subjects (p < 0.05) but was independent of body mass index.

CONCLUSIONS

This multicenter study provides gastric emptying values in healthy subjects based on data obtained using a large sample size and consistent meal and methodology. Gastric retention of >10% at 4 h is indicative of delayed emptying, a value comparable to those provided by more intensive scanning approaches. Gastric emptying of a low fat meal is initially faster in men but is comparable in women at 4 h; it is also faster in older individuals but is independent of body mass.

Autonomic function in cyclic vomiting syndrome and classic migraine

Cyclic vomiting syndrome is an idiopathic disorder characterized by attacks of severe vomiting, interspersed with normal periods, and found in patients with a family history of migraine headaches. In this report, we investigated the characterization of the autonomic abnormalities in cyclic vomiting syndrome, contrasting them with values in pediatric population, as well as adults with migraine headache. We studied five groups: 41 normal pediatric controls (NPC), 12 patients with pediatric chronic vomiting (PCV), 15 patients with cyclic vomiting syndrome (CVS), 21 adults patients with migraine headaches (MHA), and 40 normal adult controls (NAC). We studied the sympathetic and cholinergic functions: two measures of sympathetic adrenergic function-vasoconstriction to cold and postural adjustment ratio; two measures of vagal cholinergic function--Valsalva ratio and ECG R-R interval; and one measure of total autonomic score. Comparisons were performed between and within groups by t tests and reported as mean +/- SEM. Although cholinergic function measures were lower in cyclic vomiting and migraine groups, the most distinct abnormality was low postural adjustment ratio in both cyclic vomiting and migraine groups vs normal pediatric and pediatric chronic vomiting groups. There was also a significant difference between cyclic vomiting and pediatric chronic vomiting groups (P < 0.05 in three other parameters). Cyclic vomiting syndrome is associated with distinctive adrenergic autonomic abnormalities similar to those in patients with migraine headaches and is usually characterized by a low postural adjustment ratio. These findings may have implications for both confirmation and diagnosis of cyclic vomiting syndrome.

A double-blind multicenter comparison of domperidone and metoclopramide in the treatment of diabetic patients with symptoms of gastroparesis

OBJECTIVE

A double-blind, multicenter, randomized trial was conducted to compare the side effects and efficacy of domperidone and metoclopramide in symptomatic diabetic gastroparesis.

METHODS

Ninety-three insulin-dependent diabetes patients with a > or = 3-month history of gastroparesis symptoms were recruited; 48 received domperidone 2 x 10-mg tablets 4 times daily, and 45 received metoclopramide 1 x 10-mg tablet + 1 placebo tablet 4 times daily. Nausea, vomiting, bloating/distension, and early satiety were evaluated for severity after 2 and 4 wk. Adverse central nervous system (CNS) effects of somnolence, akathisia, asthenia, anxiety, depression, and reduced mental acuity were elicited and graded for severity at 2 and 4 wk.

RESULTS

Domperidone and metoclopramide were equally effective in alleviating symptoms of diabetic gastroparesis. Elicited adverse CNS effects were more severe and more common with metoclopramide. Somnolence was acknowledged by 49% of patients (mean severity score, 1.03) after 4 wk of metoclopramide compared with 29% of patients (mean severity score, 0.49) after 4 wk of domperidone (incidence, p = 0.02; severity; p = 0.03). A reduction in mental acuity was acknowledged by 33% of patients (mean severity score, 0.62) after 4 wk of metoclopramide, compared with 20% of patients (mean severity score, 0.27) after 4 wk of domperidone (incidence, p = 0.04; severity, p = 0.04). Akathisia, asthenia, anxiety, and depression were also acknowledged less often, and at a lower severity, after 4 wk of domperidone, although these differences were not statistically significant.

CONCLUSIONS

Domperidone and metoclopramide effectively reduce the symptoms of diabetic gastroparesis; CNS side effects are more pronounced with metoclopramide.

A double-blind multicenter comparison of domperidone and metoclopramide in the treatment of diabetic patients with symptoms of gastroparesis

OBJECTIVE

A double-blind, multicenter, randomized trial was conducted to compare the side effects and efficacy of domperidone and metoclopramide in symptomatic diabetic gastroparesis.

METHODS

Ninety-three insulin-dependent diabetes patients with a > or = 3-month history of gastroparesis symptoms were recruited; 48 received domperidone 2 x 10-mg tablets 4 times daily, and 45 received metoclopramide 1 x 10-mg tablet + 1 placebo tablet 4 times daily. Nausea, vomiting, bloating/distension, and early satiety were evaluated for severity after 2 and 4 wk. Adverse central nervous system (CNS) effects of somnolence, akathisia, asthenia, anxiety, depression, and reduced mental acuity were elicited and graded for severity at 2 and 4 wk.

RESULTS

Domperidone and metoclopramide were equally effective in alleviating symptoms of diabetic gastroparesis. Elicited adverse CNS effects were more severe and more common with metoclopramide. Somnolence was acknowledged by 49% of patients (mean severity score, 1.03) after 4 wk of metoclopramide compared with 29% of patients (mean severity score, 0.49) after 4 wk of domperidone (incidence, p = 0.02; severity; p = 0.03). A reduction in mental acuity was acknowledged by 33% of patients (mean severity score, 0.62) after 4 wk of metoclopramide, compared with 20% of patients (mean severity score, 0.27) after 4 wk of domperidone (incidence, p = 0.04; severity, p = 0.04). Akathisia, asthenia, anxiety, and depression were also acknowledged less often, and at a lower severity, after 4 wk of domperidone, although these differences were not statistically significant.

CONCLUSIONS

Domperidone and metoclopramide effectively reduce the symptoms of diabetic gastroparesis; CNS side effects are more pronounced with metoclopramide.

Effect of leuprolide acetate in treatment of abdominal pain and nausea in premenopausal women with functional bowel disease: a double-blind, placebo-controlled, randomized study

We have previously reported impressive results in using a gonadotropin-releasing hormone analog, leuprolide acetate (Lupron), in the treatment of moderate to severe symptoms (especially abdominal pain and nausea) in patients with functional bowel disease (FBD). Pain is the hallmark of patients with FBD, and there is no consistent therapy for the treatment of these patients. The purpose of the present study was to expand the investigation to study similar patients (menstruating females) in a multicenter, double-blind, placebo-controlled, randomized study using Lupron Depot (which delivers a continuous dose of drug for one month), 3.75 mg (N = 32) or 7.5 mg (N = 33), or placebo (N = 35) given intramuscularly every four weeks for 16 weeks. Symptoms were assessed using daily diary cards to record abdominal pain, nausea, vomiting, early satiety, anorexia, bloating, and altered bowel habits. Additional assessment tools were quality of life questionnaires, psychological profile, oral-to-cecal transit using the hydrogen breath test, antroduodenal manometry, reproductive hormone levels, and global evaluations by both patient and investigator. Patients in both Lupron Depot-treated groups showed consistent improvement in symptoms; however, only the Lupron Depot 7.5 mg group showed a significant improvement for abdominal pain and nausea compared to placebo (P < 0.001). Patient quality of life assessments and global evaluations completed by both patient and investigators were highly significant compared to placebo (P < 0.001). All reproductive hormone levels significantly decreased for both Lupron Depot-treated groups by week 4 and were significantly different compared to placebo at week 16 (P < 0.001). This study shows that leuprolide acetate is effective in controlling the debilitating symptoms of abdominal pain and nausea in patients with FBD.

Biliary, pancreatic, and sphincter of Oddi electrical and mechanical signals recorded during ERCP

Measurements of biliary tract motility have focused on radiologic and pressure measurements to quantify biliary motility rather than measurements of electrical activity of the biliary tract. We previously reported the recording of biliary electrical signals during ERCP and now report on the continued development and validation of a system to measure biliary tract electrical activity as well as biliary mechanical activity. In 26 patients presenting with a variety of clinical indications, we recorded measurements of electrical activity from the common bile duct sphincter (16 patients), pancreatic duct sphincter (eight patients), and/or sphincter of Oddi (eight patients). Electrical recordings were performed with a specially modified ERCP catheter, using two circular electrodes as well as a custom catheter that measured both electrical and mechanical activity. Electrical activity of the biliary tract was successfully recorded in 25 of 26 patients (96%), including the common bile duct sphincter (16 patients, 62%), pancreatic duct sphincter (eight patients, 31%) and sphincter of Oddi (eight patients, 31%). Along with the electrical recordings, common bile duct sphincter mechanical activity was recorded in 12 patients (67%), pancreatic duct sphincter mechanical activity in six patients (33%), and sphincter of Oddi mechanical activity in six patients (33%). Frequency analysis of electrical signals revealed a mean frequency (cycles/min) of 4.7 +/- 0.5 in the common bile duct sphincter, 4.1 +/- 0.6 in the pancreatic duct sphincter, and 4.9 +/- 0.7 in the sphincter of Oddi. Phasic mechanical frequency in cycles per minute was recorded at a frequency of 4.8 +/- 0.5 in common bile duct sphincter, 4.0 +/- 0.6 in pancreatic duct sphincter, and 5.3 +/- 0.9 in sphincter of Oddi. Tonic pressure (averaged 12.1 +/- 1.5 mm Hg) in common bile duct sphincter, 12.4 +/- 1.4 mm Hg in pancreatic duct sphincter, and 15.0 +/- 5.1 mm Hg in sphincter of Oddi. Analysis of wave form propagations (noted as percentage antegrade, retrograde, or indeterminant) revealed 50% antegrade, 23% retrograde, and 27% indeterminant). One patient was recorded on two occasions via ERCP; the same patient had an intraoperative recording. All three recordings showed similarities. We conclude that measurements of biliary, pancreatic, and sphincter of Oddi electrical and mechanical activity are feasible and can be done as part of ERCP. There was good correlation between biliary tract electrical and mechanical events and different wave form characteristics were noted for different parts of the biliary tree. Further studies are warranted to evaluate the potential usefulness of measurement of biliary tract electrical activity, and to confirm its correlation with mechanical events in the pancreato-biliary tree.

Efficacy of electrical stimulation at frequencies higher than basal rate in canine stomach

The optimum frequency for electrically stimulating motility in the stomach is still in question. Some studies of gastric electrical stimulation (GES) at near physiologic frequencies have reported gastric electrical entrainment but with little efficacy in improving motility. In this study we examined the effectiveness of electrical stimulation at a broad range of frequencies in entraining gastric electrical activity (GEA) and eliciting contractions in a canine model. The stomachs of six dogs, each implanted with four pairs of stainless steel electrodes and two strain gauges were stimulated at frequencies ranging from 3 to 30 cycles/min. GEA and contractions were monitored before and during electrical stimulation. The ability of GES at different frequencies to reverse the effect of glucagon was also investigated. GEA was entrained in most animals at frequencies close to the intrinsic rate as well as at four to five times the intrinsic rate. At other stimulation frequencies, the recorded electrical control activity either remained unchanged, uncoupled, or became dysrhythmic. Contractile response to stimulation at four to five times the intrinsic rate were significantly higher than those at frequencies close to the intrinsic rate (P < 0.05). GES did not alter the effect of glucagon. Stimulation at a frequency of four times the basal rate of 5/min elicited the largest motility index in dogs. Stimulation at frequencies much higher than the physiologic rate warrants further study as a possible optimum range for GES.

Symptom improvement from prokinetic therapy corresponds to improved quality of life in patients with severe dyspepsia

Prokinetic therapy has been shown to improve patients' symptoms associated with gastrointestinal motility disorders and quality of life. This study investigated the correlation between clinical improvement and quality of life after 12 months of treatment with cisapride or domperidone in patients with severe dyspepsia. Psychological and quality-of-life measures were assessed at baseline and after 12 months of therapy using three patient-administered, standardized questionnaires: the Minnesota Multiphasic Personality Inventory, the Millon Behavioral Health Inventory, and the Sickness Impact Profile. Changes in clinical symptoms were correlated with changes in these measures. Twenty-seven patients with symptoms of severe dyspepsia were treated with cisapride or domperidone (60-80 mg/day) for 12 months. Symptoms and quality-of-life measures were improved at the end of therapy. There were significant correlations between improvement in clinical symptoms and improvement in quality of life parameters. Patients with more marked symptom improvement had more significant improvements in quality of life measures. We conclude that prokinetic therapy improved symptoms and quality of life. Standardized questionnaires can be used to quantify response to prokinetic therapy and to individualize treatment regimens for patients with dyspepsia who have specific psychologic or behavioral characteristics.

Gastrointestinal motility disorders

A careful history can localize gastrointestinal motility disorders and suggest appropriate diagnostic tests. Dysphagia, odynophagia, heartburn and reflux have esophageal origins. The same symptoms occur in achalasia, a classic motor disorder of the lower esophageal sphincter, which can be diagnosed by barium swallow, endoscopy and esophageal motility studies. Nausea, vomiting, anorexia, bloating and abdominal pain are symptoms of motor disorders of the stomach and small intestine. When these symptoms are accompanied by unexplained right upper quadrant pain, elevated liver enzyme levels and unexplained recurrent pancreatitis, the diagnosis of impaired biliary motility is suggested. Colorectal motility disorders may present as abdominal pain, diarrhea, constipation and/or fecal incontinence. If symptoms do not resolve with dietary changes and appropriate medications and the anatomy is normal on lower gastrointestinal studies, colorectal motility studies may be indicated.

Case report: interaction of rifampin and nortriptyline

Rifampin is well documented to cause numerous clinically significant drug interactions because of its induction of the hepatic cytochrome P450 system. The metabolism of nortriptyline and other tricyclic antidepressants is induced and inhibited by this enzyme system. To the authors' knowledge, this is only the second case report in the literature regarding a possible interaction between rifampin and a tricyclic antidepressant. Nortriptyline serum concentrations were not detectable while rifampin was given concurrently. Two weeks after discontinuation of rifampin, nortriptyline concentrations increased dramatically. Further study of this possible interaction is warranted.

A model of gastric electrical activity in health and disease

The idea of diagnosing gastric dysfunction from noninvasive measurements of gastric electrical activity (GEA) is intuitively appealing, but the predictive accuracy of the cutaneous signal, especially that of its amplitude, is still in question. Mathematical modeling provides a means of investigating, analyzing, and predicting GEA measured percutaneously. In this study, a model of GEA applicable both in health and disease was developed and simulated for a cylindrical body surface. Body-surface maps of the simulated electrogastrogram (EGG) were generated at a 20 by 20 array of sites on the model's surface, and the accuracy of the percutaneous method in detecting simulated gastric electrical abnormalities was determined. The relationship between the amplitude of the simulated surface EGG and the velocity of propagation of the myogenic activity was also investigated. This was compared to a similar investigation of the fluctuations in the amplitude of the surface EGG with the velocity of propagation of the serosal activity measured in humans. The diagnostic accuracy of the measured cutaneous EGG in humans was also determined. The results obtained from the mathematical model show that the amplitude of the electrogastrogram increases with the propagation velocity of GEA. Similar results were obtained from the experimental measurements. The amplitude of the simulated and measured cutaneous signal correlated well (p < 0.05) with the phase shift of the simulated and measured activities, (-0.85, -0.54), respectively. Serosal normal activity, tachygastria, and uncoupling were detected 67%, 90%, and 0% of the time, respectively, at the cutaneous electrode in humans. In simulations, normal activity and tachygastria were accurately detected at all 400 sites on the surface. Uncoupling simulated with 50% of the myogenic sources "diseased" was detected at only 20 of the 400 sites. The results confirm that the amplitude of the cutaneous signal is a function of the velocity of propagation of the myogenic signal. It also confirms that while GEA in health may be accurately predicted from percutaneous recordings, frequency and phase/coupling abnormalities are poorly detected from single-channel electrogastrograms. This suggests the use of multiple-channel surface recordings in clinical electrogastrography.

Measurement of gastric and small bowel electrical activity at laparoscopy

Recordings of gastric electrical activity can be employed in the diagnosis of certain gastric motility disorders. Since the best recordings are obtained from electrodes implanted at laparotomy, the scope of application of this technique is limited. The current study details a method of measuring gastric electrical activity at laparoscopy. The patients were 3 Caucasian women whose age range was 16 to 30 years. Their pertinent history included symptoms of nausea, vomiting, constipation, and abdominal pain. Gastric and small bowel electrical activity was measured with stainless steel electrodes implanted into the serosa of the stomach and small bowel at laparoscopy. Laparoscopy was performed for small bowel biopsy, bowel resection, or feeding tube placement. The recorded signals were evaluated by manual analysis. Good quality gastric and small bowel electrical activities were obtained. Amplitude, frequency, rhythmicity, and direction of propagation information were readily obtained by visual inspection. Laparoscopic measurement of gastric electrical activity produces excellent quality recordings comparable with recordings from electrodes implanted at laparostomy. The technique combines the advantage of laparoscopy with the usefulness of serosal measurement of gastrointestinal electrical activity.

Predominant symptoms in irritable bowel syndrome correlate with specific autonomic nervous system abnormalities

BACKGROUND/AIMS

Irritable bowel syndrome may be influenced by the autonomic nervous system. Abnormalities in autonomic function, colon transit time, and psychological profiles in 21 patients were assessed.

METHODS

Using modified Manning criteria for irritable bowel syndrome, patients were classified as constipation-predominant or diarrhea-predominant. Autonomic function was determined by one vagal cholinergic and two sympathetic adrenergic measures. Colon transit was assessed by radiopaque markers, and psychological profiles were determined by three inventories.

RESULTS

Autonomic function tests showed that diarrhea-predominant subgroup values for one sympathetic adrenergic measure (postural adjustment ratio) were significantly different from controls (P < 0.01). Constipation-predominant subgroup values were significantly lower for the vagal cholinergic measure R-R interval (P < 0.05). Colon transit measures differed by subgroup in left, right, rectosigmoid, and total colon transit times. Both subgroups differed significantly from controls on psychological measures; the constipation subgroup showed more psychological distress.

CONCLUSIONS

Irritable bowel syndrome specific-symptom subgroups had different patterns of autonomic functioning, colonic transit, and psychological measures. The constipation subgroup is associated with a cholinergic abnormality and the diarrhea-predominant subgroup with an adrenergic abnormality. These findings suggest specific associations between the autonomic nervous system, predominant physical symptoms, colon transit time, and psychological factors in patients with irritable bowel syndrome.

Improvement in autonomic and gastric function following pancreas-kidney versus kidney-alone transplantation and the correlation with quality of life

We conducted a series of studies to document changes in autonomic and gastrointestinal function following pancreas-kidney and kidney-alone transplantation, define how autonomic function is associated with quality of life, and identify how transplantation alters the quality of life of diabetic transplant recipients. Uremic type I diabetic patients receiving combined pancreas-kidney (n = 23) or kidney-alone (n = 16) transplants completed pre- and 12-month-posttransplant evaluation of vasomotor function (total capillary pulse amplitude, capillary vasoconstriction response to cold, capillary response to postural adjustments), cardiac function (R-R interval variation, valsalva ratio), overall autonomic function (total autonomic score, autonomic index), gastric function (cutaneous electrogastrography, gastric emptying, total gastrointestinal symptoms score), and quality of life (sickness impact profile). Kidney recipients experienced nonsignificant improvement in autonomic function with significant improvement in total symptom score. In contrast, pancreas-kidney recipients demonstrated significant improvement in postural adjustment ratio (P < or = .0085), valsalva ratio (P < or = .0348), electrogastography (P < or = .0159), and total symptom score (P < or = .0001). Improvement or stabilization of gastric function occurred for 12 of 23 pancreas-kidney patients (52%) versus 5 of 12 kidney-alone patients (41.7%). A path analysis of 56 diabetic patients having a wide range in diabetic autonomic neuropathy, found the sickness impact profile to correlate with valsalva ratio (r = .36, P < or = .0056), R-R interval (r = .27, P < or = .0396), and vasoconstriction (r = .24, P < or = .064). Together, autonomic function measures accounted for 15.2% of the total variance in the sickness impact profile. Sickness impact profile scores also significantly improved for both groups of transplant recipients.

Cutaneous exposure to warfarin-like anticoagulant causing an intracerebral hemorrhage: a case report

A case of intercerebral hematoma due to warfarin-induced coagulopathy is presented. The 39-year-old woman had spread a warfarin-type rat poison around her house weekly using her bare hands, with no washing post application. Percutaneous absorption of warfarin causing coagulopathy, reported three times in the past, is a significant risk if protective measures, such as gloves, are not used. An adverse drug interaction with piroxicam, which she took occasionally, may have exacerbated the coagulopathy.

Effect of cisapride therapy for severe dyspepsia on gastrointestinal symptoms and quality of life

Quality of life measures have received little attention in evaluation of therapy for dyspepsia. To examine the effect of cisapride on gastrointestinal symptoms and quality of life measures, we studied eight patients with chronic, severe dyspepsia, before and after therapy with cisapride (20 mg three times daily) for 12 months. Gastrointestinal (GI) Total Symptom Score (TSS), Overall Patient Assessment (OPA), and quality of life by both trait (Minnesota Multiphasic Personality Inventory (MMPI)) and physical function (Sickness Impact Profile (SIP)) were measured at base line and at month 12 of cisapride therapy. Results showed significant improvement in TSS, OPA, and the MMPI Depression and Anxiety scales (all, p < 0.05). Improvement in the SIP physical dimension score approached significance (p = 0.065). We conclude that, in this group of patients with severe dyspepsia, both GI symptoms and quality of life measures improved with 12 months of cisapride therapy. These quality of life measures may prove useful in evaluating the efficacy of drug treatment for dyspepsia.

Hyperemesis gravidarum

Hyperemesis gravidarum is a poorly understood disorder and one for which many physicians have little sympathy, perhaps because we find it difficult to understand its pathogenesis and to treat. It may be associated with dysfunction in a variety of organs, including the thyroid and liver. Many theories, prominently including psychological or behavioral abnormalities, have been proposed to explicate this syndrome. On examination, however, no single theory seems to provide an adequate explanation for hyperemesis gravidarum. Treatment for hyperemesis gravidarum includes fluid and electrolyte supplementation, nutritional support, and total parenteral nutrition, as well as psychological and behavioral therapies and, in selected cases, pharmacotherapy.

Long-term efficacy of oral cisapride in symptomatic upper gut dysmotility

We conducted a 12-month trial of cisapride (10 mg three times a day) in 21 patients with gastric stasis due to clinically and manometrically diagnosed gastroparesis (N = 9; seven due to diabetes) or chronic intestinal pseudo-obstruction (N = 12). Radionuclide solid-liquid gastric emptying tests were performed at baseline and at the end of the 12-month period. Symptoms were assessed monthly by diary and every three months by the investigators; frequency and severity of symptoms were scored in a standardized manner. For the whole group of 21 patients, gastric emptying of both solids and liquids improved significantly after one year of cisapride (P less than 0.05). Among chronic intestinal pseudoobstruction patients, there was predominantly an improvement in gastric emptying of solids; in contrast, patients with gastroparesis had a greater improvement in liquid emptying. Total symptom score improved significantly in the gastroparesis group (median score: 8 at baseline vs 6 at one year, P less than 0.05) but not in the chronic intestinal pseudoobstruction patients (median score at baseline 10 vs 9 at one year). Similarly, body weight showed a trend towards improvement in the gastroparesis group. No significant side effects were noted. We conclude that during a 12-month open trial, cisapride was effective in improving gastric emptying in patients with gastric stasis and consistently improved symptoms in those with gastroparesis.