Effects of gastric pacing on gastric emptying and plasma motilin

Roux-en-Y duodenojejunostomy improves gastric emptying in experimental obstruction of the distal duodenum

Introduction

We undertook a comparative survey of gastric emptying (GE) kinetics after two variants of bypass surgery for upper bowel obstruction.

Material & methods

In 10 dogs with experimental upper bowel obstruction, five were randomized to obtain gastrojejunal anastomosis (GA), and the other five received Roux-en-Y duodenojejunal anastomosis (DA). Duplicate scintigraphic measurements of GE of a solid meal were accomplished in every animal before surgery and during the early (2–3 weeks), medium (3 months), and late (6 months) post-operative period. The GE curves were fitted with a power-exponential function to derive the GE half time T½, and the curve shape parameter S.

Results

Early after surgery T½ slightly decreased by -18±21 min in the DA group and lengthened by 91±37 min in the GA group (p = 0.042). In both groups an increase in the S parameter was found then. In either group T½ gradually declined towards the basal value during the medium and late post-operative period. On the other hand, net differences relative to the basal situation in the S values appeared to be positive in the GA group (0.32±0.11 at 3 months; 0.64±0.19 at six months), and negative in the DA group (-0.30±0.09 at 3 months; -0.01±0.20 at six months). Hence a statistically significant contrast was found between those differences: p = 0.0022 at 3 months, and p = 0.045 at six months after the surgery.

Conclusion

Roux-en-Y duodenojejunal anastomosis appears to be superior to the classical gastrojejunal anastomosis while restoring patency of the gastrointestinal passage in the case of upper bowel obstruction.

Comparative Researches of Semen Arecae and Charred Semen Arecae on Gastrointestinal Motility, Motilin, Substance P, and CCK in Chronically Stressed Rats

Aims

To compare the effects of Semen Arecae (SA) and Charred Semen Arecae (CSA) on gastrointestinal motility, motilin, substance P (SP), and cholecystokinin (CCK) in chronically stressed rats.

Methods

Rats were randomly divided into control group and stress group. Rats in stress group were randomly exposed to a variety of unpredictable stimulations for 21 days. Then, the rats were treated orally with distilled water, SA, CSA, and mosapride for 7 days. Gastric residue rate and intestinal propulsion rate were evaluated. Serum levels of motilin and SP were measured by enzyme-linked immunosorbent assay (ELISA). CCK mRNA was quantified by using quantitative real-time PCR (qRT-PCR).

Results

Both SA and CSA improved the intestinal propulsion and reduced the gastric residue in chronically stressed rats. Furthermore, the serum levels of motilin and SP were significantly higher and the CCK mRNA expressions in intestine and hypothalamus were downregulated in SA and CSA groups. Furthermore, it was found that CSA is more effective.

Conclusion

Both SA and CSA enhanced gastrointestinal motility and increased serum levels of motilin and SP in chronically stressed rats via downregulating CCK mRNA expressions in intestine and hypothalamus. Importantly, CSA possessed more effective promoting effects.

Study on effects of electrical stimulation on rabbit esophageal body motility in vivo

Electric stimulation (ES) could induce contraction of intestinal smooth muscle. The aim of this study was to analyze the effects of ES on esophageal motility and the underlying mechanism in vivo. Twenty-eight rabbits were equipped with a pair of subserosa electrodes (connected to an electrical stimulator) in the lower segment of the esophagus. The ES signal consisted of bipolar rectangular pulse trains, lasting for 3 s, with different amplitudes (1 mA, 3 mA, 5 mA and 10 mA), and frequencies (10 Hz, 20 Hz and 50 Hz). The amplitude of the contraction was recognized by high-resolution manometry. The effect of ES was tested under anesthesia and following administration of atropine, phentolamine or L-NAME. ES induced esophageal contraction at the stimulated site. A statistically significant increase in esophageal pressure was observed when the stimulation amplitude was above 3 mA. The increase in esophageal pressure was associated with the amplitude of stimulus as well as the frequency. During stimulation, atropine, phentolamine and L-NAME had no effect on the increase of esophageal pressure induced by ES. These findings implied that ES induced esophageal contraction were not mediated via the NANC, adrenergic or cholinergic pathway. The amplitude of esophageal contraction was current and frequency dependent.

Early Assessment of Cost-effectiveness of Gastric Electrical Stimulation for Diabetic Nausea and Vomiting

Background/Aims

Recurrent nausea and/or vomiting are common complications of diabetes mellitus. The conditions severely impact the quality of life of patients and often cause repeated admissions to hospital incurring significant healthcare costs. If standard treatment fails, gastric electrical stimulation (GES) may be offered in selected cases, as a minimally invasive, but expensive, therapeutic option. Our aims are to evaluate the clinical effect and the cost-utility of GES as a treatment for severe diabetic recurrent nausea and/or vomiting.

Methods

Among 33 diabetes patients implanted with GES because of recurrent nausea and/or vomiting, 30 were available for evaluation. The effect of treatment was assessed prospectively using symptom-diaries and the SF-36 questionnaires at baseline, after 6 and 12 months, and thereafter yearly. The number of days in hospital due to symptoms related to gastrointestinal dysfunction was calculated using hospital records 12 months prior to and 12 months after implantation.

Results

The surgical procedures were performed without mortality or major complications. Six months after surgery 78% of the respondents had at least 50% reduction in time with nausea and 48% had at least 50% reduction in days with vomiting. Symptom relief persisted at follow-up after at least 4 years. Quality adjusted life years improved after GES, which was cost-effective after 24 months.

Conclusions

GES reduces symptoms and improves quality of life in diabetes patients with recurrent nausea and/or vomiting. The procedure is supposed as cost-effective over a 2-year time horizon.

Reduction of gastrointestinal motility by unilateral thyroparathyroidectomy plus subdiaphragmatic vagotomy in rats

AIM: To investigate whether the combined methods of unilateral thyroparathyroidectomy (TPX) and subdiaphragmatic vagotomy (VAX) can be adapted for rats and used as a reliable method to produce a rat model of long-term reduction of gastrointestinal (GI) motor function.

METHODS: Male Sprague-Dawley rats were randomly divided into 3 groups, normal, sham-operated and unilateral TPX plus VAX. The TPX plus VAX rats received VAX 7 d after application of TPX, and dietary intake and fecal output were then measured daily for 1 wk. After completion of the experiments, gastric emptying and small bowel transit were measured in vivo, and the contractile responses of colonic strips to excitatory and inhibitory neurotransmitters were estimated using isometric force transducers in vitro.

RESULTS: In comparison with normal and sham-operated rats, rats which received unilateral TPX plus VAX showed a significant decrease in body weight and in fecal pellet number and weight throughout the entire week. Application of TPX plus VAX to rats markedly delayed gastric emptying and small bowel transit. In TPX plus VAX rats, the longitudinal muscles of the proximal colon showed a significant reduction in contractile responses to acetylcholine (5 × 10^-6 mol/L), and a dramatic attenuation of contractile responses was also observed in both the longitudinal and circular muscles of the distal colon. However, the spontaneous contractility of the colonic strips from TPX plus VAX rats was not significantly affected by treatment with N-nitro-L-arginine-methyl ester (0.1 mol/L).

CONCLUSION: The results indicate that unilateral TPX plus VAX reduced the motor function of the GI tract in rats, and the reduced gut motility is likely mediated, at least in part, by inhibition of the excitatory neurotransmitter system.

Simotang enhances gastrointestinal motility, motilin and cholecystokinin expression in chronically stressed mice

AIM: To investigate the effect of Simotang (Decoction of Four Powered Drugs) on gastrointestinal motility, motilin and cholecystokinin expression in chronically stressed mice.

METHODS: Forty mice were randomly divided into control group, stress group (model group), mosapride group and Simotang group, 10 in each group. A variety of unpredictable stimulations were used to induce chronic stress in mice. Then, the mice were treated with distilled water, mosapride or Simotang for 7 d. Gastric emptying and intestinal propulsion function were detected. Serum level of motilin was measured by enzyme-linked immunosorbent assay. Expression of cholecystokinin (CCK) in intestine, spinal cord and brain of mice was detected by immunohistochemistry and semi-quantitative reverse transcription polymerase chain reaction, respectively.

RESULTS: Simotang improved the gastric emptying and intestinal propulsion in chronically stressed mice. Furthermore, the serum motilin level was significantly higher and the expression levels of CCK-positive cells and genes were significantly lower in intestine, spinal cord and brain of Simotang group than in those of model group (P < 0.05). No significant difference was found in serum motilin level and expression levels of CCK-positive cells and genes between the mosapride and Simotang groups.

CONCLUSION: Simotang enhances the gastrointestinal motility in chronically stressed mice by regulating the serum motilin level and the expression of cholecystokinin.

Cutaneous gastric electrical stimulation alters gastric motility in dogs: New option for gastric electrical stimulation?

BACKGROUND AND AIM

We investigated the effects of cutaneous gastric electrical stimulation (CGES) on gastric myoelectrical activity, postprandial antral contractions and gastric tone in dogs.

METHODS

CGES was carried out via abdominal surface electrodes over the stomach. After an overnight fast, gastric slow waves were recorded from the serosal electrodes in six dogs at a frequency of 4.4 cycles/min (c.p.m.) or 10 c.p.m. Nine dogs were used for the measurement of postprandial antral contractions. Gastric tone at baseline and during CGES was measured in six of the dogs.

RESULTS

We found that: (i) CGES at 4.4 c.p.m. decreased slow wave frequency (5.1 vs 4.6 c.p.m., P < 0.05) and increased slow wave power (-6.2 vs 2.7 c.p.m., P < 0.05); CGES at 10 c.p.m. increased slow wave frequency (5.1 vs 9.2 dB, P < 0.05) and decreased normal slow waves (85.4% vs 60.0%, P < 0.05); (ii) CGES at 10 c.p.m. significantly suppressed postprandial antral contractions (P < 0.01); (iii) CGES had no effects on gastric tone.

CONCLUSIONS

CGES is capable of altering gastric slow waves and inhibiting gastric motility. It may have therapeutic potential for treating eating disorders, such as obesity. However, clinical studies are needed to explore the potential of CGES.

Effect of acupuncture at Foot-Yangming Meridian on gastric mucosal blood flow, gastric motility and brain-gut peptide

AIM: To observe the effect of acupuncture at Foot-Yangming Meridian on gastric mucosal blood flow (GMBF), gastric motility and brain-gut peptide.

METHODS: Sixty SD rats were randomly divided into 6 groups: normal control group, model group (group with gastric mucosal damage, GMD), Sibai group (with acupuncture at Sibai point + GMD), Tianshu group (with acupuncture at Tianshu point + GMD), Zusanli group (with acupuncture at Zusanli point + GMD) and non-acupoint group (with acupuncture at non-acupoint + GMD). The GMD model group was induced by infusing pure alcohol into gastric cavity. H₂ Gas Clearance Test (HGCT) was used to measure GMBF, the frequency and amplitude of gastric motility were measured by the method of aerocyst, the content of brain-gut peptide in sinus ventriculi and bulbus medullae were detected by radioimmunoassay.

RESULTS: Inhibitory effect of the frequency and amplitude of gastric motility were shown in model group, and the rates of frequency and amplitude changes were remarkably different from the normal control group (-19.41 ± 17.21 vs -4.71 ± 10.32, P < 0.05; -51.61 ± 29.02 vs 1.81 ± 14.12, P < 0.01). In comparison with control group, the GMBF was 0.52 ± 0.161 mL vs 1.03 ± 0.255 mL per 100g tissue/min, P < 0.01, the content of motilin in sinus ventriculi and bulbus medullae was 63.04 ± 7.77 pg/mL vs 72.91 ± 8.42 pg/mL, P < 0.05 and 50.96 ± 8.77 pg/mL vs 60.76 ± 8.05 pg/mL, P < 0.05, but the content of somatostatin in sinus ventriculi and bulbus medullae was 179.85 ± 43.13 ng/g vs 90.54 ± 40.42 ng/g, P < 0.01 and 532.86 ± 122.58 ng/g vs 370.91 ± 76.29 ng/g, P < 0.05,respectively. In comparison with model group, the amplitude of gastric motility was 1.52 ± 20.13, -6.52 ± 23.31, 6.92 ± 25.21 vs -51.61 ± 29.02, P < 0.01 and GMBF was 0.694 ± 0.160 mL vs 0.893 ± 0.210 mL, 1.038 ± 0.301 mL vs 0.52 ± 0.161 mL per 100g tissue/min, P < 0.01, respectively in Tianshu, Sibai and Zusanli groups, the content of motilin in sinus ventriculi and bulbus medullae was 71.64 ± 9.35 pg/mL vs 63.04 ± 7.77 pg/mL, P < 0.05; 58.96 ± 6.69 pg/mL vs 50.96 ± 8.77 pg/mL, P < 0.05 in Zusanli group and 72.84 ± 8.62 pg/mL vs 63.04 ± 7.77 pg/mL, P < 0.05 in Sibai group, while the content of somatostatin in bulbus medullae in Tianshu, Sibai and Zusanli groups was 480.62 ± 151.69 ng/g, 388.53 ± 155.04 ng/g, 365.76 ± 143.93 ng/g vs 532.86 ± 122.58 ng/g, P < 0.05, respectively.

CONCLUSION: Electro-acupuncture at acupoints of Foot-Yangming Meridian could enhance the gastric motility, improve GMBF, and regulate the content of motilin and somatostatin in sinus ventriculi and bulbus. The effects of acupuncture on GMBF and gastric motility may be related to the content of brain-gut peptide.

Correlation between gastric myoelectrical activity recorded by multi-channel electrogastrography and gastric emptying in patients with functional dyspepsia

OBJECTIVE

To investigate the correlation between the parameters of multi-channel electrogastrography (MEGG) and gastric emptying in patients with functional dyspepsia.

MATERIAL AND METHODS

The MEGG study included 19 patients with functional dyspepsia and 19 healthy subjects. MEGG was recorded for 30 min in the fasting state and 60 min after a standard test meal (450 kcal). MEGG parameters included the power ratio (PR), the normal percentage of 2-4 cpm gastric slow waves (N%) and the percentage of slow wave coupling (%SWC). Gastric emptying was measured in the 19 patients by SPECT (single photon emission computerized tomography) and the gastric emptying parameters included lag phase (LP), half time of gastric emptying (T1/2), emptying rate of stable phase (ERSP), one hour retention rate (1HRR), and two hour retention rate (2HRR).

RESULTS

No significant difference in MEGG parameters was found between normal subjects and patients. There was a significant negative correlation between postprandial N% and LP (r = - 0.52, p<0.05) and a significant negative correlation between fasting %SWC and 1HRR (r = - 0.48, p<0.04) or 2HRR (r = - 0.48, p<0.05). Compared with the patients in the PR > 1 group, patients in the PR < or = 1 group had significantly higher T1/2 and 2HRR but lower ERSP.

CONCLUSIONS

Both the temporal regularity and spatial regularity of gastric slow waves have negative correlations with gastric emptying, which suggests that the impaired gastric myoelectrical activity may be responsible for the delayed gastric emptying in patients with functional dyspepsia.

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.