Nizatidine accelerates gastric emptying of a solid meal in rats

Acotiamide improves stress-induced impaired gastric accommodation

BACKGROUND

Gastric accommodation is a reflex reaction related to gastric reservoir function. Psychological stress, such as anxiety, inhibits gastric accommodation in humans. Acotiamide enhances the effect of acetylcholine in the enteric nervous system, enhances gastric contractility, and accelerates delayed gastric emptying. However, the effect of acotiamide on stress-induced impaired gastric accommodation remains unclear. Therefore, we examined the effect of acotiamide on gastric accommodation and stress-induced impaired gastric accommodation using a conscious guinea pig model.

METHODS

A polyethylene bag was inserted through the distal region of the gastric body into the proximal stomach of 5-week-old male Hartley guinea pigs. Gastric accommodation was evaluated by measuring the intrabag pressure in the proximal stomach after oral administration of a liquid meal. In the stress model, animals were subjected to water-avoidance stress. Acotiamide (Z-338) or nizatidine was administered subcutaneously. Fecal output was determined as the number of fecal pellets.

KEY RESULTS

Administration of the liquid meal significantly decreased intrabag pressure, indicating induction of gastric accommodation. Acotiamide treatment prolonged liquid meal-induced gastric accommodation and significantly increased the number of fecal pellets compared to controls. Water-avoidance stress significantly inhibited liquid meal-induced gastric accommodation. Pretreatment with acotiamide significantly improved stress-induced impaired gastric accommodation. The number of fecal pellets in the acotiamide group increased significantly compared to controls. Acotiamide, but not nizatidine, significantly decreased gastric emptying.

CONCLUSIONS & INFERENCES

Acotiamide prolongs gastric accommodation and improves stress-induced impaired gastric accommodation, indicating a potential role for acotiamide in the treatment of functional dyspepsia through its effects on gastric accommodation reactions.

Semi-quantitative Multispectral Optoacoustic Tomography (MSOT) for volumetric PK imaging of gastric emptying

A common side effect of medication is gastrointestinal intolerance. Symptoms can include reduced appetite, diarrhea, constipation, GI inflammation, nausea and vomiting. Such effects often have a dramatic impact on compliance with a treatment regimen. Therefore, characterization of GI tolerance is an important step when establishing a novel therapeutic approach. In this study, Multispectral Optoacoustic Tomography (MSOT) is used to monitor gastrointestinal motility by in vivo whole body imaging in mice. MSOT combines high spatial and temporal resolution based on ultrasound detection with strong optical contrast in the near infrared. Animals were given Indocyanine Green (ICG) by oral gavage and imaged by MSOT to observe the fate of ICG in the gastrointestinal tract. Exponential decay of ICG signal was observed in the stomach in good correlation with ex vivo validation. We discuss how kinetic imaging in MSOT allows visualization of parameters unavailable to other imaging methods, both in 2D and 3D.

Nizatidine ameliorates gastroparesis in Parkinson's disease: a pilot study

BACKGROUND

The objective of this work was to perform an open trial of the effects of nizatidine (NZT), a selective histamine H2-receptor antagonist and a cholinomimetic, on gastroparesis in Parkinson's disease (PD) patients, using objective parameters given by a gastric emptying study using a (13) C-sodium acetate expiration breath test.

METHODS

Twenty patients with PD were enrolled in the study. There were 13 men and 7 women; aged 68.0 ± 7.72 years; disease duration 5.50 ± 3.62 years. All patients underwent the breath test and a gastrointestinal questionnaire before and after 3 months of administration of NZT at 300 mg/day. Statistical analysis was performed by Student t test.

RESULTS

NZT was well tolerated by all patients and none had abdominal pain or other adverse effects. NZT significantly shortened Tmax ((13) C) (the peak time of the (13) C-dose-excess curve) (P < 0.05).

CONCLUSIONS

Although this is a pilot study, we found a significant shortening of gastric emptying time after administration of NZT in PD patients.

Does the use of nizatidine, as a pro-kinetic agent, improve gastric emptying in patients post-oesophagectomy?

PURPOSE

Delayed gastric emptying following oesophagectomy is common and can often lead to weight loss, malnutrition and a poor quality of life. Animal models have shown that nizatidine, a histamine H2-receptor antagonist, has pro-kinetic properties and can accelerate gastric emptying. Patients post-oesophagectomy require long-term acid suppression medication; if nizatidine can improve gastric emptying, it can be adopted for its dual pharmacological actions.

METHODOLOGY

Twenty consecutive patients were prospectively enrolled in this trial following oesophagectomy. All patients were more than 6 months post-surgery and had no evidence of recurrent cancer. A baseline nuclear medicine scan following a radiolabelled meal was conducted and then repeated after 1 week of nizatidine (150 mg bd) treatment. Quality of life and eating comfort data were collected.

RESULTS

Oesophagectomy causes a significant delay in gastric emptying. Early satiety (80%) and reflux (65%) were the most common post-operative complaints. The percentage of food remaining in the stomach at 60 min post-meal was significantly more than normal values in both the pre- and post-nizatidine studies. There is no advantage in using nizatidine as a pro-kinetic agent.

CONCLUSIONS

Impaired gastric emptying post-surgery causes a change in eating habits. Patients in this study did not lose a significant amount of weight despite all indicating worse eating comfort. Patients required more regular meals or snacks throughout the day and avoid foods that are difficult to swallow. It is likely that gastric motility only plays a small role in the emptying process and gravity combined with appropriate drainage procedures (pyloroplasty/pyloromyotomy) at the time of surgery are more important.

Nizatidine and gastric emptying in functional dyspepsia

In clinical practice, H2-receptor antagonists, including nizatidine, in addition to their use in the treatment of peptic ulcer and gastroesophageal reflux, are also useful in alleviating dyspeptic symptoms. Patients with functional dyspepsia show a tendency to delayed gastric emptying. Results of preliminary studies have demonstrated that nizatidine has a prokinetic effect due to its cholinergic properties. The aim of this study was to evaluate the effect of nizatidine on gastric emptying in patients with functional dyspepsia. Sixteen patients with dyspeptic symptoms referred for gastroscopy by primary care physicians were enrolled in this randomized, placebo-controlled, double-blind cross-over study. They received nizatidine 150 mg twice daily or placebo for 2 months. After a 1-month washout period, the 2-month treatment was repeated, with these patients acting as their own controls. Gastric emptying was measured by scintigraphy, and dyspeptic symptoms and quality of life were evaluated at the end of both treatment periods. Gastric emptying of solids during nizatidine therapy was prolonged (T1/2 110.1 +/- 76.7 vs. 65.6 +/- 23.2 min, P = 0.03), but nizatidine had no effect on gastric emptying of liquids. Nizatidine improved the symptom scores and seven of eight aspects of quality of life - but not significantly. In conclusion, nizatidine decreases the gastric emptying rate of solids without having a significant effect on symptoms or quality of life in functional dyspepsia.

Influence of acid suppressants on gastric emptying: cross-over analysis in healthy volunteers

BACKGROUND

Gastric emptying plays an important role in gastroesophageal reflux disease. Acid suppressants such as H2 receptor antagonists and/or proton pump inhibitors are often used in patients with gastroesophageal reflux disease. However, it remains controversial whether H2 receptor antagonists and proton pump inhibitors delay or accelerate gastric emptying. Here, the influence of acid suppressants on gastric emptying was evaluated via a cross-over study using the [13C]-labeled acetate breath test.

METHODS

Twenty normal male subjects without gastroesophageal reflux disease symptoms were enrolled. Gastric emptying was investigated five times in every subject by the [13C]-labeled acetate breath test with oral administration of the vehicle, domperidone, and three acid suppressants: ranitidine, famotidine and rabeprazole. Gastric emptying was estimated by the values of T(max-calc), T(1/2) and %dose/2 h calculated from the 13CO2 breath excretion curve.

RESULTS

Using the T(max-calc) values, rabeprazole, ranitidine and famotidine did not influence gastric emptying time in comparison with vehicle administration. Using the T(1/2) and %dose/2 h values, rabeprazole tended to delay gastric emptying. Domperidone produced a statistically significant acceleration of gastric emptying for all three variables (P < 0.05).

CONCLUSION

Oral dosage of the H2 receptor antagonists, ranitidine and famotidine, has no significant effect on gastric emptying. However, rabeprazole may delay gastric emptying more strongly than H2 receptor antagonists.

Effect of Barley Endoprotease EP-B2 on Gluten Digestion in the Intact Rat

Celiac Sprue is a multifactorial disease characterized by an intestinal inflammatory response to ingested gluten. Proteolytically resistant gluten peptides from wheat, rye, and barley persist in the intestinal lumen and elicit an immune response in genetically susceptible individuals. Here, we demonstrate the in vivo ability of a gluten-digesting protease ("glutenase") to accelerate the breakdown of a gluten-rich solid meal. The proenzyme form of endoprotease B, isoform 2 from Hordeum vulgare (EP-B2), was orally administered to adult rats with a solid meal containing 1 g of gluten. Gluten digestion in the stomach and small intestine was monitored as a function of enzyme dose and time by high-performance liquid chromatography and mass spectrometry. In the absence of supplementary EP-B2, gluten was solubilized and proteolyzed to a limited extent in the stomach and was hydrolyzed and assimilated mostly in the small intestine. In contrast, EP-B2 was remarkably effective at digesting gluten in the rat stomach in a dose- and time-dependent fashion. At a 1:25 EP-B2/gluten dose, the gastric concentration of the highly immunogenic 33-mer gliadin peptide was reduced by more than 50-fold within 90 min with no overt signs of toxicity. Evaluation of EP-B2 as an adjunct to diet control is therefore warranted in celiac patients.

Noninvasive Assessment of Gastric Emptying by Near-Infrared Fluorescence Reflectance Imaging in Mice: Pharmacological Validation with Tegaserod, Cisapride, and Clonidine

Noninvasive near-infrared fluorescence reflectance imaging (FRI) is an in vivo technique to assess physiological and molecular processes in the intact organism. Here we describe a method to assess gastric emptying in mice. TentaGel beads with covalently bound cyanine dye (Cy5.5) conjugates as fluorescent probe were administered by oral gavage. The amount of intragastric beads/label was derived from the fluorescence signal intensity measured in a region of interest corresponding to the mouse stomach. The FRI signal intensity decreased as a function of time reflecting gastric emptying. In control mice, the gastric half-emptying time was in agreement with literature data. Pharmacological modulation of gastric motility allowed the evaluation of the sensitivity of the FRI-based method. Gastric emptying was either stimulated or inhibited by treatment with the 5-HT(4) receptor agonists tegaserod (Zelnorm) and cisapride or the alpha(2)-receptor agonist clonidine, respectively. Tegaserod and cisapride dose-dependently accelerated gastric emptying. In contrast, clonidine dose-dependently delayed gastric emptying. In conclusion, FRI using fluorescently labeled beads allows the reliable determination of gastric emptying as well as the assessment of pharmacological interventions. The technique thus offers the potential to characterize molecular targets and pathways involved in physiological regulation and pharmacological modulation of gastric emptying.

Effect of nizatidine on olanzapine-associated weight gain in schizophrenic patients in Korea: a pilot study

A pilot study was conducted to evaluate the effect of nizatidine on olanzapine-associated weight gain (OAWG) in ten patients with schizophrenia and schizophreniform disorder in Korea. Psychometric ratings with positive and negative syndrome scale (PANSS) and brief psychiatric rating scale (BPRS) were measured at baseline, week 4 and week 8; as were weight and body mass index (BMI). A combination of nizatidine for 8 weeks resulted in significant reversal of weight gain without worsening the psychopathology (weight: 3.5% and BMI: 3.7%). In line with studies of Western populations, an add-on therapy of nizatidine could be an effective option for the control of weight gain in olanzapine-treated patients in Korea. Our findings call for further evaluation of the effect of this drug on OAWG, with randomized placebo-controlled studies, in Asian populations.

Prokinetic activity of nizatidine: implications for the management of patients with gastroesophageal reflux disease

Gastroesophageal reflux is a common condition caused mainly by motility disorders of the upper gastrointestinal tract. The most effective therapy combines acid suppression with a promotility agent. Nizatidine is a well-tolerated and effective histamine-2 (H2)-receptor antagonist used to suppress gastric acid secretion. Animal and human studies have conclusively demonstrated that nizatidine also has prokinetic activity comparable to that of cisapride, and its effect is evident <1 hour after administration of doses commonly used in clinical practice. This prokinetic activity occurs through noncompetitive inhibition of acetylcholine; this inhibition approximates the inhibition caused by neostigmine. Nizatidine appears to possess a prokinetic mechanism that may be helpful in treating patients with gastroesophageal reflux.