Effects of hypochlorhydria and hypergastrinemia on structure and function of gastrointestinal cells. A review and analysis

Personalizing protein nourishment

Proteins are not equally digestible-their proteolytic susceptibility varies by their source and processing method. Incomplete digestion increases colonic microbial protein fermentation (putrefaction), which produces toxic metabolites that can induce inflammation in vitro and have been associated with inflammation in vivo. Individual humans differ in protein digestive capacity based on phenotypes, particularly disease states. To avoid putrefaction-induced intestinal inflammation, protein sources, and processing methods must be tailored to the consumer's digestive capacity. This review explores how food processing techniques alter protein digestibility and examines how physiological conditions alter digestive capacity. Possible solutions to improving digestive function or matching low digestive capacity with more digestible protein sources are explored. Beyond the ileal digestibility measurements of protein digestibility, less invasive, quicker and cheaper techniques for monitoring the extent of protein digestion and fermentation are needed to personalize protein nourishment. Biomarkers of protein digestive capacity and efficiency can be identified with the toolsets of peptidomics, metabolomics, microbial sequencing and multiplexed protein analysis of fecal and urine samples. By monitoring individual protein digestive function, the protein component of diets can be tailored via protein source and processing selection to match individual needs to minimize colonic putrefaction and, thus, optimize gut health.

Gastric neuroendocrine neoplasms and proton pump inhibitors: fact or coincidence?

OBJECTIVE

Reporting on three cases of gastric neuroendocrine tumors (g-NETs) in patients taking long-term proton pump inhibitors (PPIs). These tumors are not classifiable considering current criteria. g-NETs are currently grouped as: types 1 and 2, related to hypergastrinemia due to chronic atrophic gastritis and Zollinger-Ellison syndrome respectively, and type 3, normogastrinemic and more aggressive. Although the g-NETs onset in patients taking PPIs is biologically plausible, only a few cases have been reported so far.

MATERIALS AND METHODS

From January 2005 to July 2014, 31 g-NETs were referred to our Unit: 24 (77%), one (3%) and three (10%) resulted types 1, 2 and 3, respectively. Three cases (10%) did not meet the current classification criteria.

RESULTS

The three patients were administered long-term PPIs for gastro-esophageal reflux disease. Patient 1: a 78-year-old man, with a 4-mm well-differentiated g-NET (Ki-67<1%) and marked hypergastrinemia. Patient 2: a 58-year-old man affected by a 6-mm well-differentiated (Ki-67 = 4%) g-NET, with normal gastrin levels. Patients 3: a 67-year-old woman with an 18-mm well-differentiated g-NET (Ki-67 <2%), with mild hypergastrinemia. In the three patients, histology and pertinent blood tests excluded chronic atrophic gastritis, Helicobacter pylori infection or Zollinger-Ellison syndrome. The first two patients underwent endoscopic polypectomy; in the third case total gastrectomy was performed. Further clinical, endoscopic and imaging follow-up did not show any g-NET recurrence.

CONCLUSIONS

The present data point to the existence and epidemiological relevance of g-NETs associated with PPIs intake. These neoplasms are not included in the current classification, thus their treatment and follow-up have not been established.

Pharmacodynamic and pharmacokinetic evaluation of CS-526 in cynomolgus monkeys

In the present study, we evaluated the effect of the novel acid pump antagonist 7-(4-fluorobenzyloxy)-2,3-dimethyl-1-{[(1S,2S)-2-methylcyclopropyl]methyl}-1H-pyrrolo[2,3-d]pyridazine (CS-526) on the intragastric acidity of cynomolgus monkeys. The study was performed in a crossover manner with five male animals. CS-526 was administered orally or intravenously at doses of 3.0, 10 and 30 mg/kg, or 0.3, 1.0 and 3.0 mg/kg, respectively. The time period in which the intragastric pH was 4.0 or more (Time(pH > or = 4.0)) and the median pH were calculated for 24 h after the administration. The intragastric pH was elevated after CS-526 treatment. The Time(pH > or = 4.0) was increased in a dose-dependent manner (p = 0.0292) in the oral administration, and the median pH was also increased in a dose-dependent fashion (p = 0.0491) in the intravenous administration. The plasma concentration of CS-526 and its metabolite R-130185 was increased after oral and intravenous administration of CS-526, except for one animal which did not show any detectable amount of R-130185 after intravenous administration at the lowest dose. The area under the time-concentration curve of the active component was increased in the dose proportional manner after oral and intravenous administration. The absolute bioavailability of the active component was estimated to be approximately 1%. Correlation between the pharmacodynamic parameters and the pharmacokinetic parameters was observed in oral (p = 0.0029-0.0745), but not in intravenous administration (p = 0.0558-0.2789). In conclusion, oral and intravenous administration of CS-526 showed inhibition on gastric acidity in cynomolgus monkeys using intragastric pH-metry and some pharmacokinetic and pharmacodynamic parameters were well correlated.

Pernicious anemia in a patient with Type 1 diabetes mellitus and alopecia areata universalis

A 27-year-old male, who had developed diabetes mellitus type 1 (DMT1) since the age of eighteen and alopecia areata universalis nine months later, attended the outpatient clinics complaining of general fatigue and shortness of breath. A Schilling test was indicative of pernicious anemia. Antigastric parietal cell (AGPA) and anti-intrinsic factor antibodies were positive, confirming diagnosis of pernicious anemia. Thyroid and Addison's disease were excluded. Gastroscopy revealed atrophic gastritis without any evidence of carcinoid tumors. The aim of this case, which, to our knowledge, is the first one to describe a correlation between diabetes mellitus Type 1 (DMT1), pernicious anaemia, and alopecia areata universalis, is to remind the clinician of the increased risk of pernicious anaemia and gastric carcinoids in DMT1 patients. Screening for AGPA followed by serum gastrin and vitamin B(12) levels constitute the most evidence-based diagnostic approach.

Effects of dexlansoprazole MR, a novel dual delayed release formulation of a proton pump inhibitor, on plasma gastrin levels in healthy subjects

Dexlansoprazole MR is a modified release formulation of a proton pump inhibitor being developed for the treatment of acid-related disorders. The purpose of this study is to characterize the plasma gastrin (PG) profile associated with administration of dexlansoprazole MR. Forty-two healthy subjects receive dexlansoprazole MR 90 mg, dexlansoprazole MR 120 mg, and lansoprazole 30 mg once daily for 5 days in a randomized, open-label, 3-period crossover study with at least 14-day washout intervals. Twenty-four-hour PG profiles are obtained at baseline (day -1 of period 1) and on days 1 and 5 in each period. Fasting PG levels are determined on days 8 and 12 in periods 1 and 2. On day 1, 24-hour PG levels increase from baseline to a similar extent with all regimens. On day 5, 24-hour PG levels with both dexlansoprazole MR regimens increase further and to a similar extent and are slightly higher than PG levels with lansoprazole. For all regimens, fasting PG levels on days 5 and 6 are higher than baseline levels (P<.05) and start to decrease by day 8, returning to near baseline at day 12. In this study, dexlansoprazole MR administration results in moderate increases in PG, similar to lansoprazole, which return to baseline levels within 7 days post dosing.

Control of gastric acid secretion in health and disease

Recent milestones in the understanding of gastric acid secretion and treatment of acid-peptic disorders include the (1) discovery of histamine H(2)-receptors and development of histamine H(2)-receptor antagonists, (2) identification of H(+)K(+)-ATPase as the parietal cell proton pump and development of proton pump inhibitors, and (3) identification of Helicobacter pylori as the major cause of duodenal ulcer and development of effective eradication regimens. This review emphasizes the importance and relevance of gastric acid secretion and its regulation in health and disease. We review the physiology and pathophysiology of acid secretion as well as evidence regarding its inhibition in the management of acid-related clinical conditions.

Long-term proton pump inhibitor use in children: a retrospective review of safety

The objective of this work was to assess the efficacy of continuous proton pump inhibitor (PPI) therapy in children and to evaluate changes in biochemical, endoscopic, and histologic parameters during such treatment. A retrospective review of children receiving PPI therapy continuously for 1 year or more with baseline and follow-up esophageal and gastric biopsies on treatment was conducted to assess type, frequency, and duration of PPI dosing, symptom relief, gastrin levels, histologic findings, and adverse events. A total of 113 children (59 male, median age 4.5 years) were identified. Of these, 31% (35/113) were neurologically impaired. The median treatment duration was 35.2 months. Elevated serum gastrin levels occurred in 73% of children with no statistically significant differences in gastrin level by PPI type, dose, and dosing frequency or treatment duration. Adverse events were reported by 12% of children: diarrhea (5%) and constipation (4%) were the most frequent. Long-term PPI therapy appears to be effective, safe and well tolerated in children despite some biochemical, endoscopic, and histologic changes.

Pharmacological profile of novel acid pump antagonist 7-(4-fluorobenzyloxy)-2,3-dimethyl-1-{[(1S,2S)-2-methyl cyclopropyl]methyl}-1H-pyrrolo[2,3-d]pyridazine (CS-526)

The pharmacological profiles of the novel acid pump antagonist 7-(4-fluorobenzyloxy)-2,3-dimethyl-1-{[(1S,2S)-2-methylcyclopropyl]methyl}-1H-pyrrolo[2,3-d]pyridazine (CS-526) were investigated in terms of hog gastric H+,K+-ATPase activity, gastric acid secretion, and acute gastroesophageal lesions in comparison with other proton pump inhibitors (PPIs). CS-526 inhibited H+,K+-ATPase activity in a concentration-dependent manner, with an IC50 value of 61 nM. The inhibitory effect of CS-526 on H+,K+-ATPase activity was more potent than that of any of the other PPIs examined. The inhibitory mechanism of CS-526 on H+,K+-ATPase was a competitive antagonism to the K+ binding site of H+,K+-ATPase, and it was also a reversible inhibition. In pylorus-ligated rats, intraduodenal or oral administration of CS-526 inhibited gastric acid secretion in a dose-dependent manner, and the ID50 values were 2.8 or 0.7 mg/kg, respectively. In Heidenhain pouch dogs, intrapouch administration of CS-526 inhibited histamine-stimulated gastric acid secretion in a dose- and retention time-dependent manner. In a reflux esophagitis model, intraduodenal and oral administration of CS-526 prevented esophageal lesions with ID50 values of 5.4 and 1.9 mg/kg, respectively. Lansoprazole prevented esophagitis only by intraduodenal administration (ID50 = 2.2 mg/kg). Furthermore, CS-526 inhibited acute gastric mucosal lesions. These data demonstrate that the novel acid pump antagonist CS-526 has potent antisecretory and antiulcer effects. These findings indicate that CS-526 would have a curative effect on gastroesophageal reflux disease via its potent antisecretory and antiulcer actions.

Long-term prevention of erosive or ulcerative gastro-oesophageal reflux disease relapse with rabeprazole 10 or 20 mg vs. placebo: results of a 5-year study in the United States

BACKGROUND

Erosive gastro-oesophageal reflux disease (GERD) is a chronic condition requiring long-term maintenance treatment. However, few trials of proton pump inhibitors in maintaining healing of erosive or ulcerative GERD are conducted for longer than 1 year.

AIM

To compare the efficacy and safety of 10- and 20-mg rabeprazole with placebo in the 5-year maintenance of healing in patients previously diagnosed with erosive/ulcerative GERD healed in an acute efficacy trial.

METHODS

Patients (N = 497) were randomized to receive once-daily doses of 10- or 20-mg rabeprazole or placebo. The primary efficacy measure was endoscopically documented absence of oesophageal erosions or ulcerations.

RESULTS

After 5 years, relapse rates in both rabeprazole groups were significantly lower than with placebo (rabeprazole 20 mg, 11%; 10 mg, 23%; placebo, 63%; P < 0.001 for rabeprazole vs. placebo; P = 0.005 for rabeprazole 20 mg vs. 10 mg). Both rabeprazole doses were significantly superior to placebo in preventing relapse of heartburn frequency and improving patient quality of life. Analyses of adverse events, biopsy findings and laboratory values showed no evidence of clinically significant effects.

CONCLUSIONS

Five-year maintenance therapy with rabeprazole is effective in preventing relapse of erosive or ulcerative GERD and is well tolerated.

Effect of CYP2C19 polymorphism on the safety and efficacy of omeprazole in Japanese patients with recurrent reflux oesophagitis

BACKGROUND

The polymorphic enzyme cytochrome P450 2C19 affects omeprazole metabolism. This influence on metabolism might affect serum gastrin levels, and safety, during long-term treatment of reflux oesophagitis.

AIM

To examine the relationship between cytochrome P450 2C19 genotype and the safety profile of long-term omeprazole treatment.

METHODS

A total of 119 Japanese patients with recurrent reflux oesophagitis underwent cytochrome P450 2C19 genotyping prior to receiving daily omeprazole 10 mg or 20 mg for 6-12 months, during which adverse event frequency, serum gastrin levels and endoscopic findings were monitored.

RESULTS

The incidences of adverse events, serious adverse events and adverse events leading to withdrawal did not differ between homozygous extensive metabolizer (n = 46), heterozygous extensive metabolizer (n = 53) or poor metabolizer (n = 20) groups. In all genotype groups, serum gastrin increased during the first 3 months of dosing but stabilized thereafter. No significant differences were seen either in the rate of reflux oesophagitis healing or symptom improvement among genotype groups.

CONCLUSIONS

Long-term treatment with omeprazole was well-tolerated in Japanese patients, irrespective of their cytochrome P450 2C19 metabolic genotype, indicating that dose adjustment depending on metabolic genotype is not required during treatment with omeprazole.

Effects of 5 years of treatment with rabeprazole or omeprazole on the gastric mucosa

BACKGROUND

Prolonged gastric acid suppression leads to hypergastrinaemia, which promotes hyperplasia of the enterochromaffin-like (ECL) cells of the oxyntic mucosa. The objective was to determine the effects of 5 years of treatment with rabeprazole or omeprazole on the gastric mucosa.

METHODS

Two hundred and forty-three patients received rabeprazole (20 mg or 10 mg) or omeprazole (20 mg) once daily for up to 5 years, for gastro-oesophageal reflux disease and 51% completed the whole 5 year period. Gastric biopsy specimens were taken and examined for gastritis, Helicobacter pylori infection, and ECL cell status.

FINDINGS

H. pylori infection in the gastric corpus was more common than in the antrum, and remained constant, whereas antral H. pylori infection became less common as the study progressed. H. pylori infection was a highly significant predictor of higher gastritis scores, which were similar among the three treatment groups. ECL cell hyperplasia occurred in a minority of patients, and was associated with serum gastrin concentrations. No ECL cell dysplasia or tumours were observed. There were no significant differences among the treatment groups in gastritis or ECL cell hyperplasia grades.

INTERPRETATION

This study has confirmed the link between ECL cell hyperplasia and elevated serum gastrin concentrations, but has found no evidence that this progresses to high grades of hyperplasia during 5 years of treatment with rabeprazole or omeprazole.

Gastric outlet obstruction as a consequence of a duodenal web masquerading as gastrinoma in an adult

We present the case of a 24-year-old man with recurrent peptic ulcers and hypergastrinemia, in whom a multidisciplinary investigation for gastrinoma revealed a duodenal web. The affected duodenal segment was excised, and a gastroduodenostomy with highly selective vagotomy was performed. Postoperative serum gastrin levels returned to the normal range over the next 6 weeks. Congenital duodenal anomalies are unusual causes of gastric outlet obstruction in adults. Chronic gastric outlet obstruction secondary to an adult duodenal web can induce neurohumoral changes in gastric function, which enhance both acid output and gastrin secretion. This case reminds clinicians to consider congenital anomalies in adults presenting with recurrent peptic ulcers and hypergastrinemia.

Effect of long-term, continuous versus alternate-day omeprazole therapy on serum gastrin in patients treated for reflux esophagitis

BACKGROUND

Proton pump inhibitors have been proven to have a major role in the management of peptic diseases, especially the long-term control of reflux esophagitis. The potent inhibitory effect of omeprazole on gastric acid secretion is frequently associated with hypergastrinemia, and gastrin and its intermediates have been reported to promote gastrointestinal cellular functions and cell growth. Experimental data suggest that gastrin may affect the proliferation of colon cells and some other cancer cells. However, so far the direct role of gastrin in tumorigenesis is unclear. Although most clinical studies on long-term treatment with omeprazole or other proton pump inhibitors do not report serious adverse effects, the issue of prolonged hypergastrinemia and tissue growth is unsettled, and many clinicians are reluctant to recommend long-term use of omeprazole or of other proton pump inhibitors.

STUDY

We examined the effect of long-term omeprazole treatment on serum gastrin levels in patients with reflux esophagitis when given either 20 mg daily (group 1) or on alternate days (group 2). During the follow-up period, clinical remission was monitored and maintained in all patients in group 1 and in the majority of patients in group 2.

RESULTS

The mean serum gastrin level was significantly elevated in group 1 (mean +/- SE, 159 +/- 23.6 pg/mL; range, 45-620 pg/mL; n = 31) as compared with the alternate-day treatment group (group 2) (66 +/- 4.8 pg/mL; range, 37-115 pg/mL; n = 21) (p < 0.005). In controls, serum gastrin levels showed similar values to those found in group 2 (54 +/- 4.3 pg/mL; range, 27-94 pg/mL; n = 20). Fourteen patients (45%) in group 1 had serum gastric ranging from 140 to 620 pg/mL, and 8 (25%) had a 6-fold or greater increase in serum gastrin. The follow-up treatment period ranged between 3 and 60 months (mean +/- SE, 16.1 +/- 2.1 months) for group 1 and 3-36 months (9.7 +/- 1.4 months) for group 2. Upon multivariate adjustment for age and duration of treatment, a significantly lower mean serum gastrin level was observed in the alternate-day group as compared with the daily treated group.

CONCLUSION

Alternate-day, long-term treatment with omeprazole may be adequate to maintain remission in patients with reflux esophagitis. This regimen can assure serum gastrin levels within the normal range, thus reducing the potential risk of prolonged, sustained hypergastrinemia and profound hypochlorhydria.

Postprandial cell proliferation in the esophageal epithelium of rats

Food intake is known to trigger cell growth in the mucosa of several gut segments. In this study, the effects of both oral feeding and intragastric feeding on cell proliferation in the esophageal epithelium of rats were examined. A similar study was carried out in antrectomized animals. Refeeding of fasted rats either orally or through an intragastric catheter increased the esophageal epithelial labeling index (LI) 310 and 445%, respectively, while the mitotic index (MI) increased 427 and 217%, respectively. Under the same experimental settings, the serum gastrin values increased 423 and 200%, respectively. After surgical resection of the antrum, a postprandial proliferative wave was still observed in the orally fed rats, with an increase in LI and MI of 114 and 166%, but not in the animals refed through the gastrostomy. This study demonstrates the growth stimulating effect of feeding on the rat esophageal epithelium. This effect appears to be triggered by the mechanical passage of food and the antral release of a systemic factor, which is most probably gastrin.

Long term omeprazole therapy for reflux esophagitis: Follow-up in serum gastrin levels, EC cell hyperplasia and neoplasia

AIM: To evaluate the long-term safety of omeprazole in patients of gastroesophageal reflux disease resistant to treatment with H2 receptor antagonist.

METHODS: We prospectively followed 33 patients on omeprazole therapy for severe erosive esophagitis for 5-8 years, with periodic gastrin levels, H. pylori infection, gastric biopsies for incidence of ECL cell hyperplasia, carcinoids, gastric atrophy and neoplasia. A total 185 patient follow-up years and 137 gastric biopsies were done.

RESULTS: Among the 33 patients, 36% reached their peak gastrin levels in an average of 8 mo to one year, then drifted Down slowly over 1-2 year period to just above their baseline level, 24% of the patients had a peak gastrin level above 400 ng·L^-1 and one patient had a peak level above 1000 ng·L^-1. One patient had a mild ECL cell hyperplasia which was self-limiting and did not show any dysplastic changes. Eighteen percent of patients were positive for H. pylori infection. The gastric biopsies did not show gastric atrophy, intestinal metaplasia or neoplastic changes.

CONCLUSION: In a series of 33 patients followed for 5-8 years on omeprazole therapy for severe reflux esophagitis, we did not observe any evidence of significant ECL cell hyperplasia, gastric atrophy, intestinal metaplasia, dysplasia or neoplastic changes.

Gastric carcinoid tumors as a consequence of chronic hypergastrinemia: spiral CT findings

The development of gastric carcinoid tumors is a rare but recognized complication of prolonged, severe hypergastrinemia. We present 2 patients with elevated gastrin levels who developed gastric carcinoid tumors and the CT findings are reviewed.

Autoimmune hepatitis, autoimmune gastritis, and gastric carcinoid in a type 1 diabetic patient: a case report

The history of a 45-year-old male type 1 diabetic patient is presented. At the age of 29 years, he was diagnosed to have an autoimmune hepatitis with incipient liver cirrhosis. Five years later, a successful liver/pancreas transplantation was performed. Eighteen months later, however, pancreatic insufficiency occurred due to thrombosis of the pancreatic graft. Besides these conditions, iron deficiency, pernicious anemia, and autoimmune gastritis were also diagnosed. Serum parietal cell antibodies (PCA) and intrinsic factor antibodies (AIF) were positive. At 45, this patient was found to have a gastric carcinoid tumor. The clinical importance of PCA is discussed with regard to chronic atrophic gastritis and pernicious anemia, which both predispose toward gastric carcinoid tumors. Autoimmune type 1 diabetic patients who have a high prevalence of PCA should be screened for gastric autoimmune manifestations and tumors, as the history of this patient illustrates.

Review article: current perspectives on hypergastrinaemia and enterochromaffin-like-cell hyperplasia

Rabeprazole, a new benzimidazole proton pump inhibitor (PPI), is among a class of agents known to be very potent inhibitors of gastric acid secretion. PPIs inhibit hydrogen-potassium adenosine triphosphatase activity on the luminal surface of the parietal cell, effectively blocking the final common pathway for gastric acid secretion. Raising gastric pH stimulates the production of gastrin by G cells in the antrum of the stomach, which can lead to enterochromaffin-like (ECL)-cell hyperplasia. In the past, these changes have been viewed with concern, particularly in the light of studies in rats indicating that hypergastrinaemia and ECL-cell hyperplasia induce gastric carcinoid tumour formation. All available clinical data indicate that long-term PPI use does not lead to carcinoid tumour formation in humans. In fact, both serum gastrin elevation and ECL-cell hyperplasia are now generally viewed as normal physiological responses to gastric acid suppression. Serum gastrin concentrations, in particular, correlate well with gastric acid suppression, which has led to the use of gastrin response by some investigators as a surrogate marker of antisecretory effectiveness. Long-term tolerability data indicate that PPIs have a favourable side-effect profile. Data obtained from patients receiving acute or long-term maintenance rabeprazole therapy support this conclusion. Furthermore, neither animal nor human data obtained with rabeprazole suggest a significant risk for neoplastic changes secondary to hypergastrinaemia.

Lessons from genetically engineered animal models. III. Lessons learned from gastrin gene deletion in mice

Gastrin is the principal hormonal inducer of gastric acid secretion. Chronic hypergastrinemia, leading to hypersecretion of gastric acid and increased proliferation of parietal and enterochromaffin-like (ECL) cells, has been well described. In contrast, the physiological consequences of chronic gastrin deficiency had been poorly understood until the recent genetic engineering of mouse mutants containing a gastrin gene deletion by homologous recombination in embryonic stem cells. This themes article describes the consequences of constitutive gastrin deficiency on the development and physiology of the stomach. A lack of gastrin disrupts basal gastric acid secretion and renders the acid secretory system unresponsive to acute histaminergic, cholinergic, and gastrinergic stimulation. The defect in acid secretion is greater than would have been predicted from previous studies in which gastrin action was acutely blocked. Cellular changes include thinning of the gastric mucosa in the gastrin-deficient mice, with a reduction in parietal cells and reduced expression of markers of parietal and ECL cell-differentiated functions. The results suggest that gastrin is required for the functional maturation of the acid-secretory system.

Endocrine cells in the upper gastrointestinal tract in relation to gastrointestinal dysfunction in patients with familial amyloidotic polyneuropathy

Gastrointestinal (GI) dysfunction is a common complication of familial amyloidotic polyneuropathy (FAP). In previous reports, a decreased content of small and large intestinal endocrine cells has been found in patients with FAP and it has been suggested that this may contribute to the development of GI disturbances. The aim of the present study was to investigate the endocrine cell content in the stomach and duodenum of FAP patients, and to correlate the findings with gastric emptying. Fifteen patients with FAP were included in the study. Twenty-eight subjects with macroscopically and histologically normal mucosa were used as controls for endocrine cell contents and 14 healthy subjects for gastric scintigraphy. The endocrine cells were identified by immunohistochemistry and quantified with image analysis. Gastric emptying time was detected by scintigraphy and endoscopy. The number of chromogranin A-immunoreactive (IR) cells was reduced in all investigated parts of the GI tract except bulbus duodeni. Gastrin/CCK cell content was reduced in duodenum, but tended to be increased in antrum of the stomach (P = 0.07). Otherwise, the content of all other endocrine cells types in the upper GI tract was reduced compared with controls. A correlation with malnutrition was found for gastric inhibitory polypeptide and secretin cell content in bulbus duodeni. Gastric scintigraphy disclosed delayed gastric emptying of solid food, but the finding was not correlated to the decreased content of neuroendocrine cells. The severity of endocrine cell depletion was not correlated to duration of GI disturbances. The present study showed that the endocrine cells of the stomach are affected in FAP patients and that the abnormalities in the upper GI endocrine cells occur early during the course of the disease.

Safety profile of Lansoprazole: the US clinical trial experience

OBJECTIVE

Lansoprazole has undergone extensive clinical evaluation for the treatment of acid-peptic diseases. The aim of this study was to define the safety profile of lansoprazole and compare it to that of other therapeutic agents evaluated in the same controlled trials.

METHODS

The clinical safety profile of lansoprazole and comparative agents (placebo, ranitidine and omeprazole) was reviewed for 3281 patients who participated in short term (up to 8 weeks) and long term (up to 56 months) clinical trials conducted in the US. Adverse events, laboratory value changes and gastric biopsy changes that occurred during treatment were compared statistically for differences between treatments.

RESULTS

The incidence of adverse events and number of patients discontinuing treatment because of adverse events was similar for lansoprazole and comparative agents. Other than elevated serum gastrin levels, a known effect of proton pump inhibitors, no trends in laboratory changes were observed. Median values for gastrin levels remained within the normal range; about 2% of patients had gastrin levels >400 pg/ml at any time, while <1% had 2 or more gastrin values >500 pg/ml. Values returned to baseline levels after therapy was discontinued. No significant changes in gastric endocrine cell growth from baseline to final visit were observed, nor was there evidence of dysplasia or neoplasia.

CONCLUSION

Lansoprazole is well tolerated for both short and long term treatment of acid-related disease. The tolerability of lansoprazole is comparable to that of ranitidine, omeprazole and placebo in the treatment of these diseases.

Proton pump inhibitors. Pharmacology and rationale for use in gastrointestinal disorders

Proton pump inhibitors (PPIs) are drugs which irreversibly inhibit proton pump (H+/K+ ATPase) function and are the most potent gastric acid-suppressing agents in clinical use. There is now a substantial body of evidence showing improved efficacy of PPIs over the histamine H2 receptor antagonists and other drugs in acid-related disorders. Omeprazole 20 mg/day, lansoprazole 30 mg/day, pantoprazole 40 mg/day or rabeprazole 20 mg/day for 2 to 4 weeks are more effective than standard doses of H2-receptor antagonists in healing duodenal and gastric ulcers. Patients with gastric ulcers should receive standard doses of PPIs as for duodenal ulcers but for a longer time period (4 to 8 weeks). There is no conclusive evidence to support the use of a particular PPI over another for either duodenal or gastric ulcer healing. For Helicobacter pylori-positive duodenal ulceration, a combination of a PPI and 2 antibacterials will eradicate H. pylori in over 90% of cases and significantly reduce ulcer recurrence. Patients with H. pylori-positive gastric ulcers should be managed similarly. PPIs also have efficacy advantages over ranitidine and misoprostol and are better tolerated than misoprostol in patients taking nonsteroidal anti-inflammatory drugs (NSAIDs). In endoscopically proven gastro-oesophageal reflux disease, standard daily doses of the PPIs are more effective than H2-receptor antagonists for healing, and patients should receive a 4 to 8 week course of treatment. For severe reflux, with ulceration and/or stricture formation, a higher dose regimen (omeprazole 40 mg, lansoprazole 60 mg, pantoprazole 80 mg or rabeprazole 40 mg daily) appears to yield better healing rates. There is little evidence that PPIs lead to resolution of Barrett's oesophagus or a reduction of subsequent adenocarcinoma development, but PPIs are indicated in healing of any associated ulceration. In Zollinger-Ellison syndrome, PPIs have become the treatment of choice for the management of gastric acid hypersecretion.

Gastrin and colorectal cancer: a prospective study

BACKGROUND & AIMS

Gastrin is a putative promoter of colorectal carcinomas. The aim of this study was to evaluate the temporal relationship between gastrinemia and development of colorectal malignancy.

METHODS

We conducted a nested case-control study among 128,992 subscribers to a health maintenance program who had participated in a multiphasic health checkup between 1964 and 1969. Serum had been frozen since the checkup and the cohort followed up for cancer. Of 1881 incident colorectal carcinoma cases, 250 were randomly selected; 1 control without cancer was matched to each case by age, sex, education, and date of serum collection. Stored sera were tested for Helicobacter pylori immunoglobulin G and for gastrin and glycine-extended gastrin.

RESULTS

Verified cases included 166 colon cancers, 58 rectal cancers, and 9 with cancer in both locations. A mean of 15.3 years had elapsed between serum collection and diagnosis of cancer. Median gastrin levels were similar in cases and controls (41.7 vs. 40.7 pg/mL). However, a gastrin level above normal was associated with increased risk for colorectal malignancy (odds ratio, 3.9; 95% confidence interval, 1.5-9.8). If this association is causal, 8.6% of colorectal cancers could be attributed to high serum gastrin level.

CONCLUSIONS

Hypergastrinemia is associated with an increased risk of colorectal carcinoma.

Hypergastrinaemia during long-term omeprazole therapy: influences of vagal nerve function, gastric emptying and Helicobacter pylori infection

AIM

elucidate the mechanisms that lead to severe hypergastrinaemia during long-term omeprazole therapy for gastro-oesophageal reflux disease (GERD).

PATIENTS AND METHODS

A total of 26 GERD patients were studied during omeprazole maintenance therapy. Twelve patients with severe hypergastrinaemia (gastrin > 400 ng/L) were compared with 14 control patients (gastrin < 300 ng/L). Helicobacter pylori serology and a laboratory screen were obtained in all patients. Gastric emptying was scored by the evidence of food remnants upon endoscopy 12 h after a standardized meal. Gastric antrum and corpus biopsies were analysed for histological parameters, as well as somatostatin and gastrin concentrations. All patients underwent a meal-stimulated gastrin test and the hypergastrinaemia patients also underwent a vagal nerve integrity assessment by pancreatic polypeptide testing (PPT).

RESULTS

Severe hypergastrinaemia patients had a longer duration of treatment (80 vs. 55 months; P = 0.047) and were characterized by a higher prevalence of H. pylori infection (9/12 vs. 2/14, P = 0.004), corpus mucosal inflammation and atrophic gastritis (P < 0.04). This was reflected in lower serum pepsinogen A concentrations (mean +/- S.E.M. 53.6 +/- 17.9 vs. 137 +/- 16.0 mg/L, P = 0.03), pepsinogen A/C ratio (1.8 +/- 0.3 vs. 4.1 +/- 0.6, P = 0.005) and mucosal somatostatin concentrations (2.75 +/- 0.60 vs. 4.48 +/- 1.08 mg/g protein, P = 0.038). Two patients in the hypergastrinaemia group had signs of delayed gastric emptying, but none in the normogastrinaemia group did (P = N.S.). In addition, both groups had a normal meal-stimulated gastrin response.

CONCLUSION

Severe hypergastrinaemia during omeprazole maintenance therapy for GERD is associated with the duration of therapy and H. pylori infection, but not with abnormalities of gastric emptying or vagal nerve integrity.

A placebo-controlled dose-ranging study of lansoprazole in the management of reflux esophagitis

OBJECTIVE

We compared the efficacy of three different doses of the proton pump inhibitor lansoprazole in the management of reflux esophagitis.

METHODS

Two hundred ninety-two patients with endoscopically confirmed reflux esophagitis were enrolled in a double-blind, multicenter study and were randomized to lansoprazole 15, 30, or 60 mg or placebo administered once daily for 8 wk.

RESULTS

Healing rates after 4 wk of lansoprazole 15, 30, and 60 mg/d were 67.6%, 81.3%, and 80.6%, respectively. These were all significantly superior (p < 0.001) to placebo, which produced endoscopic healing in only 32.8% of the patients after 4 wk. The 4-wk healing rates with lansoprazole 30 or 60 mg were significantly higher than that with lansoprazole 15 mg (p < 0.05), confirming a dose-response effect. Cumulative healing rates after 8 wk of treatment were 52.5% with placebo and 90.0%, 95.4%, and 94.4% with lansoprazole 15, 30, and 60 mg, respectively (p < 0.001 for all doses of lansoprazole vs placebo). Lansoprazole was also significantly superior to placebo in relieving symptoms in patients with reflux esophagitis. Lansoprazole was well tolerated, and no serious treatment-related adverse events were encountered. Up to 3 months after discontinuation of treatment, all lansoprazole-treated groups had more patients free of endoscopic evidence of esophagitis than the group treated with placebo.

CONCLUSIONS

Lansoprazole was safe and effective for the treatment of reflux esophagitis in this trial. This study indicates that the optimum daily dose of lansoprazole for reflux esophagitis is 30 mg.

Antisecretory and antiulcer effect of T-330, a novel reversible proton pump inhibitor, in rats

The antisecretory and antiulcer effects of T-330 (2-[(2-dimethylaminobenzyl)sulfinyl]-1-(3-methylpyridine-2-yl)imidazole) , a novel reversible proton pump inhibitor, were studied in rats. T-330 suppressed dibutyryl cyclic AMP-stimulated acid formation in isolated rat gastric mucosal cells with the IC50 value of 0.57 microM. In chronic fistula rats, intravenous, intraduodenal and oral administration of T-330 inhibited pentagastrin-stimulated gastric acid secretion; the ED50 values calculated from the peak inhibition were 0.36, 0.43 and 0.73 mg/kg, respectively. T-330 also reduced dimaprit-stimulated gastric acid secretion following its intraduodenal injection (ED50 0.85 mg/kg). The antisecretory activities of T-330 following its intraduodenal and oral administration were 3-6- and 4-10-times more potent than those of omeprazole and ranitidine, respectively, while the duration of action of T-330 was apparently shorter than that of omeprazole and was almost equal to that of ranitidine. Oral or duodenal administration of T-330 inhibited the development of acid-related damage (water-immersion- and aspirin-induced gastric lesions, cysteamine-induced duodenal ulcers and reflux esophagitis) with equal or higher potency than omeprazole or ranitidine. Furthermore, T-330 prevented ethanol-induced gastric lesions. These findings indicate that T-330 exerts its antiulcer effect mainly via its potent antisecretory action and partly via its gastroprotective action.

Biology of gut cholecystokinin and gastrin receptors

1. The stomach hormone gastrin and the intestinal hormone cholecystokinin (CCK) share a common C-terminal pentapeptide sequence but have different biological roles. Gastrin is the major stimulant of gastric acid secretion and has a growth stimulatory effect on the secretory part of the stomach. The physiological roles of CCK are the stimulation of pancreatic secretion and the contraction of the gall-bladder. 2. Several classes of receptors have been defined for peptides of the gastrin/CCK family. The CCKA receptor on pancreatic acini has a greater affinity for sulfated CCK than for gastrin, while the gastrin/CCKB receptor in gastric mucosa and brain has similar affinities for both gastrin and CCK. Potent and selective antagonists have been developed for both receptor classes. 3. The structures of the CCKA and gastrin/CCKB receptors have been deduced from the nucleotide sequences of cloned cDNA. The receptors, which both belong to the family with seven transmembrane segments, control secretion via similar signalling mechanisms. Occupation of either receptor leads to activation of phospholipase C, with resultant increases in intracellular levels of inositol triphosphate and Ca2+. Mitogenic signalling pathways are also being defined. 4. Recent studies have questioned the previous assumption that gastrin precursors are inactive. Glycine-extended gastrin17 has been shown to stimulate mitogenesis in some cell lines and may also have an autocrine role in the growth of colonic cancers. The receptors involved, which are clearly distinct in binding properties from the CCKA and gastrin/CCKB receptors, have not yet been cloned. Specific antagonists for the novel receptors will be required to define their function in further detail.