Shigeru Yamato

Role of nitric oxide in esophageal peristalsis in the opossum

To explore the involvement of NO in normal peristalsis, the effects of inhibitors of NO synthase, including N omega-nitro-L-arginine (L-NNA) and N omega-nitro-L-arginine methyl ester (L-NAME), on esophageal peristaltic contractions induced by diverse stimuli that may involve different neuronal circuits were studied. Studies were performed in opossums. Experimental conditions in vivo included primary peristalsis (P) induced by pharyngeal stroking, short-train (1 second) electrical stimulation of the vagus nerve which caused peristaltic (S) contractions, and long-train (10 second) electrical stimulation of the vagus nerves which caused contractions at the onset of (A contractions) and after (B contractions) the stimulation period. In vitro experiments were performed on strips of esophageal circular muscle using electrical field stimulation which caused contractions at the onset of (on contractions) and after (off contractions) the stimulation period. The administration of L-NAME significantly decreased the latency period and reduced the latency gradient for P contractions, thereby increasing the velocity of peristalsis. Concomitant administration of atropine prolonged the latency period but did not restore the latency gradient. L-NAME abolished B contractions in a dose-dependent fashion. In vitro, L-NAME caused dose-dependent inhibition of off contractions and augmentation of on contractions. These studies support the hypothesis that NO may be involved in (a) both the latency period and the latency gradient, as well as in the contraction amplitude of esophageal peristalsis; and (b) esophageal B and off contractions.

Role of nitric oxide in lower esophageal sphincter relaxation to swallowing.

Studies were performed in the opossum to define the role of the L-arginine-nitric oxide (NO) pathway in lower esophageal sphincter (LES) relaxation to swallowing and vagal stimulation in viv and intramural nerve stimulation in vitro. In vivo, L-NAME, a water soluble NO synthase (NOS) inhibitor, caused antagonism of LES relaxation due to reflex-induced swallowing. L-NAME (20 mg/kg i.v.) reduced the amplitude of swallow induced relaxation from 88% to 28%. LES relaxation due to electrical stimulation of peripheral end of decentralized vagus nerve was also antagonized. The effects of L-NAME were reversed by L-arginine, but not by D-arginine. L-NAME treatment did not antagonize LES relaxation to intravenous administration of isoproterenol. In vitro, NO and sodium nitroprusside (SNP) caused a decrease in the sphincter tone. The relaxing effect caused by NO and SNP was not antagonized by tetrodotoxin or omega-conotoxin. Inhibitors of NO synthase, L-NMMA and L-NNA, caused slight increase in the spontaneous resting LES tone and concentration-dependent antagonism of electrical field stimulation (EFS) induced LES relaxation. L-NNA (10(-4)M) abolished EFS induced LES relaxation at low frequencies (less than 5 Hz) and antagonized the relaxation to a value 20% of the control at 20 Hz. The antagonistic action of L-NMMA and L-NNA was unaffected by D-arginine but was reversed by L-arginine. The inhibitory effect of NO, SNP, or two other putative inhibitory neurotransmitters (VIP and CGRP) on the LES was not antagonized by L-NNA. These studies show that inhibitors of NO synthase selectively antagonize LES relaxation to all three modes of intramural inhibitory nerve stimulation including physiological swallowing. These studies suggest that the L-arginine-nitric oxide pathway is involved in physiological relaxation of the LES.

Newly Developed Antibiotic Combination Therapy for Ulcerative Colitis: A Double-Blind Placebo-Controlled Multicenter Trial

OBJECTIVES:Fusobacterium varium may contribute to ulcerative colitis (UC). We conducted a double-blind placebo-controlled multicenter trial to determine whether antibiotic combination therapy induces and/or maintains remission of active UC.METHODS:Patients with chronic mild-to-severe relapsing UC were randomly assigned to oral amoxicillin 1500 mg/day, tetracycline 1500 mg/day, and metronidazole 750 mg/day, vs. placebo, for 2 weeks, and then followed up. The primary study end point was clinical response (Mayo score at 3 months after treatment completion) and secondary end points were clinical and endoscopic score improvements at 12 months. Anti-F. varium antibodies were measured by enzyme-linked immunosorbent assay.RESULTS:Treatment and placebo groups each had 105 subjects. At the primary end point, response rates were significantly greater with antibiotics than with placebo (44.8 vs. 22.8%, P=0.0011). Endoscopic scores significantly improved at 3 months (P=0.002 vs. placebo). Remission rates were 19.0% (antibiotics) vs. 15.8% (placebo) at 3 months (P=0.59). At the secondary end point, response rates were significantly greater with antibiotics than with placebo (49.5 vs. 21.8%, respectively, P<0.0001). Endoscopic scores were significantly improved at 12 months after antibiotic treatment (P=0.002 vs. placebo). Remission rates had improved to 26.7% with antibiotics vs. 14.9% for placebo, at 12 months (P=0.041). F. varium antibody titers decreased in responders but not in nonresponders, and more in the antibiotic than in the placebo group. More pretreatment steroid-dependent UC patients discontinued corticosteroids after treatment completion (6 months: 28.6 vs. 11.8%, respectively, P=0.046; 9 months: 34.7 vs. 13.7%, respectively, P=0.019; and 12 months: 34.7 vs. 13.7%, respectively, P=0.019). These effects were greater in the subanalysis of the active group (Mayo scores of 6–12) than in that of total cases (0–12). No serious drug-related toxicities occurred.CONCLUSIONS:The 2-week triple antibiotic therapy produced improvement, remission, and steroid withdrawal in active UC more effectively than a placebo.

Effect of 5-hydroxytryptamine receptor 4 agonist mosapride on human gastric accommodation

Impaired gastric accommodation is one of the major features of functional dyspepsia. Mosapride citrate is a 5‐hydroxytryptamine receptor 4 (5‐HT4) agonist, which is shown to improve upper abdominal symptoms. However, effect of mosapride on gastric accommodation was not clear. We tested the hypothesis that mosapride enhances the gastric accommodation in normal individuals.

Esophageal Motility and Rikkunshito Treatment for Proton Pump Inhibitor-Refractory Nonerosive Reflux Disease: A Prospective, Uncontrolled, Open-Label Pilot Study Trial

Background Only a few reports focused on esophageal motility in patients with proton pump inhibitor (PPI)-refractory nonerosive reflux disease (NERD) and there has been no established strategy for treatment. Objective To clarify the characteristics of esophageal motility in patients with PPI-refractory NERD, we evaluated esophageal function using combined multichannel intraluminal impedance and esophageal manometry (MII-EM). In addition, we evaluated the efficacy of rikkunshito (RKT), which is a gastrointestinal prokinetic agent. Methods Thirty patients with NERD were enrolled and underwent MII-EM. After 8 weeks of RKT (7.5 g/d) treatment, MII-EM was repeated on patients with PPI-refractory NERD. Symptoms were assessed by the Gastrointestinal Symptom Rating Scale. Results In patients with PPI-refractory NERD, measures of complete bolus transit, peristaltic contractions, and residual pressure of the lower esophageal sphincter during swallowing deviated from the standard values and esophageal clearance was found to be deteriorated. RKT significantly improved the peristaltic contractions (P < 0.05), the complete bolus transit (P < 0.01), and the residual pressure of lower esophageal sphincter (P < 0.05) in these patients. The overall score (P < 0.01) and the subscale scores of acid reflux syndrome (P < 0.05), abdominal pain (P < 0.05), and indigestion syndrome (P < 0.01) in the Gastrointestinal Symptom Rating Scale were significantly improved by the 8-week RKT treatment. Conclusions In the pilot study, patients with PPI-refractory NERD had disorders of esophageal and lower esophageal sphincter motility that were improved by RKT. Further studies examining esophageal motor activity of RKT in PPI-refractory NERD are required. University hospital Medical Information Network (UMIN) Clinical Trial Registry identifier: UMIN000003092.

Evaluation of Kampo medicine in the clinical practice guideline for irritable bowel syndrome.

Dear Editor, We read the comments by Dr. Yoshiharu Motoo, Department of Medical Oncology, Kanazawa Medical University [1]. Comments by readers are welcomed by the authors because active discussion is crucial to improve the clinical practice guideline for irritable bowel syndrome (IBS) [2]. Therefore, we would like to express our appreciation to the commentator on this point. However, the commentator might somewhat have misinterpreted the meaning of our statement. He wrote that in our statement there was no recommendable information on Kampo medicines. In reply to the clinical question in the guideline (‘‘Are Kampo agents effective in treating IBS?’’), we stated the following: ‘‘Kampo agents (traditional Japanese medicine) are effective in treating IBS. Kampo agents are recommended for IBS. Weak recommendation, evidence level C, Grade 2, 100 % agreed’’ [2]. Therefore, our statement in the IBS guideline is different from the commentator’s interpretation. In the IBS guideline [2], we referred to the same article he mentioned [3]. That article [3] was chosen from Japanese articles in ICHUSHI. Although this study was a randomized controlled trial (RCT), in the main analysis the improvement of abdominal pain from use of keishikashakuyakuto (n = 148) was not significantly better than that from use of placebo (n = 138) [3]. Only in the stratified analysis in the diarrhea subgroup, improvement in the keishikashakuyakuto arm was significantly better than that in the placebo arm. The commentator referred to another RCT with a small sample size [4]. It showed better outcome in the keishikashakuyakuto arm (17/23) than in the saikokeishito arm (9/23) [4]. Moreover, these studies included a short (2 weeks) or heterogeneous (4 or 8 weeks) treatment duration and an old outcome evaluation which was not recommended in the recent guidance for RCTs in IBS [5]. Even if we evaluate Kampo and Chinese herbal medicine differently, should we have regarded these studies [3, 4] as having the highest level of evidence? In the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system [6], the evidence level is strictly evaluated by the guideline committee. Not only RCTs but also studies without rate-down bias must have the highest level of evidence. From the reason stated above, we regard our statement in the IBS guideline as quite appropriate at the present time. We believe that the commentator and we have the same positive evaluation of Kampo. Appropriate design of RCTs will raise the evidence level and strengthen the statement recommending Kampo for treating IBS. Further RCTs on Kampo in IBS with a high evidence level are warranted.

W1125 Characteristics of Esophageal Motility in Patients With NERD Refractory for PPIs and a Treatment Strategy Using Rikkunshito – A Study Using Combined Multichannel Intraluminal Impedance and Manometry (MII-EM): Part II

Background: More than 50% of non-erosive gastroesophageal reflux disease (NERD) patients have a poor response to proton pump inhibitors (PPIs) treatment. Recently, it was reported that esophageal motility disorder involving a decline in esophageal clearance contributes to refractory for PPIs. However, there was few reports focused to esophageal motility of patients with NERD refractory for PPIs and there is no established strategy for treatment of refractory NERD. Aims: To clarify the characteristic of patients with refractory NERD, we investigated the esophageal function using MII-EM. In addition, we also evaluated the efficacy of rikkunshito which is a gastrointestinal prokinetic agent. Methods: In this study, 24 NERD patients including 15 patients with NERD refractory for PPIs treatment. Refractory NERD was defined as a score of more than 6 points in the QUEST questionnaire after PPI treatment for over than 4 weeks. After wash-out of gastrointestinal-related drugs, all enrolled patients underwent the examinations using MII-EM and then started oral administration of rikkunshito (7.5 g/ day). After rikkunshito treatment for 8 weeks, the examinations using MII-EM was performed again. Also, symptoms were assessed using the Gastrointestinal Symptom Rating Scale (GSRS) before and 4 weeks / 8 weeks after starting the rikkunshito treatment. Results: At first examination using MII-EM, 71.4% of the refractory NERD patients had peristaltic contraction rate (PC rate) deviating from the standard value (≧80%) and 85.7% of them had a complete bolus transit rate (CBT rate) deviating from the standard value (≧75%). On the other hand, in the 9 patients other than the refractory NERD, the rate of patients with such deviation was 25.0% and 50.0%, respectively. The rate of patients with a resting LES pressure deviating from the standard value was comparable between the two patient groups. Next, we also evaluated the efficacy of rikkunshito in the refractory NERD. Rikkunshito significantly improved the LES residual pressure during swallow from 7.2 ± 5.1 mmHg to 5.2 ± 4.1 mmHg, PC rate from 52.4 ± 34.6% to 75.5 ± 31.1% and CBT rate from 51.5 ± 27.4% to 81.8 ± 16.0%. In assesment of symptoms with GSRS, rikkunshito significantly improved score of acid reflux symptoms, dyspepsia-like symptoms and total gastrointestinal symptoms. Conclusion: These results suggested that the refractory NERD patients had a disorder of esophageal motility and that rikkunshito ameliorated the gastrointestinal symptoms through improvement of the esophageal and LES motility disorder. We propose the application of rikkunshito as a strategy to treat patients with NERD refractory for PPIs.

T1756 CRF2 Receptor Activation Enhances Nerve-Mediated Relaxation of the Rat Internal Anal Sphincter

Background Corticotropin-releasing factor (CRF) and Urocortins (Ucn) are stress-related peptides. Central or peripheral administration of these peptides has been shown to increase in colonic motor activity via CRF1 receptor. We have reported that CRF1 receptor is present in the enteric nervous system (ENS) in rat colon and direct activation of CRF1 receptor in the ENS induces colonic muscle contraction without CNS pathway (Am J Physiol 2007; 293: G903-10). In contrast to CRF1 receptor, role of CRF2 receptor in the colon has not been well studied. Aim To study whether CRF2 receptor activation cause relaxation of the colonic muscle and whether CRF2 receptor is present in the ENS. Methods Internal anal sphincter (IAS) of the rat was used in this study because IAS has resting tension and its relaxation is clearly observed. IAS circular muscle strips were suspended in an organ bath and its resting tension and electrical field stimulation (EFS) -induced relaxation were examined. The effects of Ucn 2 (selective CRF2 receptor agonist) on them were studied. To study the mechanism of action of Ucn 2, we examined these effects in the presence of tetorodotoxin (TTX), CRF1 receptor antagonist antalarmin, CRF2 receptor antagonist astressin2-B, and LNAME. The localization of Ucn 2, CRF2 receptor, and NOS in the rat IAS was investigated by immunohistochemistry using confocal laser microscope.Results IASmuscle strips showed resting tension and EFS-induced relaxation in a frequency-dependent manner. Ucn 2 caused significant decrease in resting tension of IAS dose-dependently (1 nM ~ 1 μM). In the presence of TTX, astressin2-B, and L-NAME, the effect of Ucn 2 on resting tension were abolished. Ucn 2 caused significant enhancement of EFS-induced relaxation of IAS dosedependently (1 nM ~ 10 nM). L-NAME decreased the EFS-induced relaxation, and this residual relaxation was not augmented by Ucn 2. Ucn 2 and CRF2 receptor were present in the myenteric plexus of rat IAS. Ucn 2 and NOS were colocalized in some of the myenteric neuronal cells. Discussion CRF2 receptor activation caused decrease in resting tension and augmentation of EFS-induced relaxation of IAS. These mechanisms are suggested to be through nitrergic neuronal pathway. Like anxiety or depression in CNS, CRF1 and CRF2 receptors seem to act oppositely in the gut motor activity. Conclusion CRF2 receptor activation enhances nerve-mediated relaxation of the rat IAS.

M1876 Rikkunshito Improves Esophageal Motility Disorder and Symptoms in Patients with NERD - a Study Using Combined Multichannel Intraluminal Impedance and Manometry (MII-EM) -

Background: Proton pump inhibitors (PPI) are the drug of first choice for treating patients with gastroesophageal reflux disease (GERD). However, about 50% of non-erosive reflux disease (NERD) patients have a poor response to PPI treatment. It is reported that esophageal motility disorder involving a decline in esophageal clearance contributes to the poor PPI response. Accordingly, a drug capable of enhancing esophageal motility would be beneficial in the treatment of NERD patients. Rikkunshito, a gastrointestinal prokinetic agent, is known to improve esophageal clearance in GERD patients and gastric emptying in functional dyspepsia patients and to increase secretion of ghrelin in rats. Aim: To clarify the efficacy of rikkunshito in NERD patients, we evaluated the effects of rikkunshito on esophageal and lower esophageal sphincter (LES) motility and symptoms. Methods: Fifteen patients were enrolled in the study. They were diagnosed as having NERD according to endoscopic testing and the score (6 points or more) obtained on the questionnaire for the diagnosis of reflux disease (QUEST). All patients stopped taking all gastrointestinal-related drugs for over 1 week prior to rikkunshito treatment, and were administered rikkunshito (7.5 g per day, orally) for 8 weeks. Esophageal and LES functions during liquid or semisolid swallow were evaluated using MII-EM following gold standard methods before and after rikkunshitotreatment. Symptoms were assessed using the Gastrointestinal Symptom Rating Scale (GSRS) before, 4 weeks after, and 8 weeks after treatment. Results: Rikkunshito-treatment significantly improved the mean of complete bolus transit (CBT) during liquid or semisolid swallow from 60.7±7.7% to 90.0±5.8% (p 79%, semisolid: >69%) for CBT decreased from 53.3% to 16.7% and from 60.0% to 33.3% after treatment, respectively. In manometry evaluation, rikkunshito significantly improved the mean of LES residual pressure during liquid swallow from 6.0±1.3 mmHg to 3.8±1.4 mmHg (p<0.05). In addition, rikkunshito significantly ameliorated total GI symptom scores in GSRS (from 2.1±0.2 to 1.6±0.1: (p<0.05)) and showed a tendency toward improvement of subscales for reflux symptoms, abdominal pain and dyspeptic symptoms. Conclusion: We found that rikkunshito improved the esophageal clearance and symptoms in NERD patients through the amelioration of esophageal and LES motility disorder. Thus, rikkunshito may become a useful drug for treating NERD patients.

Sequential change of esophageal nitric oxide level in experimental esophagitis in rats

G1383 SEQUENTIAL CHANGE OF ESOPHAGEAL NITRIC OXIDE LEVEL IN EXPERIMENTAL ESOPHAGITIS IN RATS. S. Yamato, K. Matsueda, M. Uchida*, R. Shoda, A. Muraoka, M. Matsukawa, K. Sekigawa, J. Akiyama, S. Fukushima, H. Ohara, A, Niihata, N. Masaki, S. Hayashi, E. Shimojo, and N. Umeda. Division of Gastroenterology, International Medical Center of Japan, Tokyo, Japan, and *Laboratory of Pharmacology, Meiji Institute of Health Science, Kanagawa, Japan.