Vagal effects on acid and pepsin secretion and serum gastrin in duodenal ulcer and controls

Presentation, response to lansoprazole therapy, and outcome of Zollinger-Ellison syndrome-like gastric acid hypersecretors

OBJECTIVE

To evaluate the clinical characteristics, response to treatment and outcome of Zollinger?Ellison syndrome (ZES)-like gastric acid hypersecretors.

METHODS

Over a 20-year period, patients with gastric acid hypersecretion in the absence of ZES were enrolled in an open label prospective trial evaluating the efficacy of lansoprazole. Following baseline evaluations, patients were treated with escalating doses of lansoprazole based on the results of gastric acid analysis. Following stabilization, patients were followed on a 6 monthly basis with interval history, physical examination, endoscopy with gastric biopsies, gastric acid analysis, and laboratory studies.

RESULTS

The study group represented 21 patients (median age 47 years, 86% male, 91% Caucasian). Historically, complicated ulcer disease was frequent and symptoms had been present for a median of 10 years before study entry. All patients responded to lansoprazole (median dose 90 mg/day) with excellent control of gastric acid hypersecretion. Mucosal relapse was infrequent and no major complications developed while on therapy.

CONCLUSIONS

ZES-like gastric acid hypersecretion presents similarly to the classic syndrome. Lansoprazole titrated to gastric acid output is effective in healing mucosal disease and preventing relapse.

Costs and risks in the management of patients with gastric acid hypersecretion

GOALS

To define both risks and costs of optimal care of patients with gastric acid hypersecretion.

BACKGROUND

The management of Zollinger-Ellison syndrome and other gastric acid hypersecretory disorders remains challenging. The optimal strategy for follow-up including gastric acid analysis, laboratory studies, and endoscopy is unknown but important given the potential complications from uncontrolled acid secretion.

STUDY

Over the last 18 years, patients with gastric acid hypersecretory disorders have been followed prospectively with gastric acid analysis and endoscopy titrating oral lansoprazole and evaluating for complications. Protocol driven charges were calculated using the most recent information available.

RESULTS

After 1 year of treatment optimization, 19 of 67 patients had 43 relapses, (once only in 10 patients). Risk markers for relapse included: (1) antrectomy, 67% relapsed versus 21% in unoperated patients; (2) basal acid output >5 mmol/h (risk=5.17); and (3) poor compliance. On treatment, 79% of 58 intact patients (excluding antrectomy) were lesion-free; 11% had only 1 relapse. Thus 90% were well managed with optimized lansoprazole alone. Protocol driven charges exceeded $25,000 the first year and $7000 annually thereafter.

CONCLUSIONS

Relapse is infrequent and generally mild with acid secreting status closely monitored. The ideal strategy to balance costs and testing awaits further study.

Vitamin B12 deficiency in hypersecretors during long-term acid suppression with proton pump inhibitors

BACKGROUND

Proton pump inhibitors (PPIs) may cause cyanocobalamin (vitamin B12) malabsorption, but measuring serum B12 alone may underestimate the prevalence. However, B12 deficiency elevates methylmalonic acid and homocysteine, both additional markers of B12 deficiency.

AIM

To determine the true prevalence of B12 deficiency and whether acid suppression by PPI caused it.

METHODS

Sixty-one acid hypersecretors (basal acid output >15 mmol/h), 46 with gastrinoma [Zollinger-Ellison (ZE) syndrome] and 15 without [acid hypersecretor without gastrinoma (pseudo-ZE)], were treated with lansoprazole to determine its long-term (up to 18 years) pharmacological and clinical efficacy and safety, particularly as regards malabsorption of B12.

RESULTS

Of 61 patients, six (10%) had low serum B12. Additional tests uncovered B12 deficiency in 13 (31%) of 41 still-available patients, despite normal serum B12. B12 replacement reduced elevated homocysteine and methylmalonic acid, supporting the diagnosis. Also, measuring both basal and stimulated gastric secretion, we found that acid suppression was neither prolonged nor profound enough to explain the B12 deficiency.

CONCLUSIONS

In long-term recipients of PPIs, B12 deficiency was more frequent (29%) than detected by measuring only serum B12, and there was not enough acid suppression to explain this deficiency.

Absence of gastrointestinal infections in a cohort of patients with Zollinger-Ellison syndrome and other acid hypersecretors receiving long-term acid suppression with lansoprazole

BACKGROUND

The relationship between proton pump inhibitor therapy and other acid suppressing medications and the risk of gastrointestinal infections remains controversial.

METHODS

Patients enrolled in a long-term trial of lansoprazole for Zollinger-Ellison syndrome and other acid hypersecretory states had interval histories taken every six months regarding hospitalizations or other intercurrent medical conditions. All medications taken were also reviewed at each visit. In addition, available patients were specifically queried during the study period 2006-2007 regarding the development of any gastrointestinal infections, hospitalizations, and prescriptions for antibiotics.

RESULTS

Ninety patients were enrolled in our long-term study and 81 were available for review. The median basal gastric pH for the cohort after stabilization on therapy was 2.9 and ranged from 1.1 - 8.4 with a median pentagastrin stimulated gastric pH of 1.60 (range 1.0 - 8.2). No patient developed a clinically significant gastrointestinal infection during the study. The median patient years of follow-up were 6.25 years.

CONCLUSION

In a cohort of patients with gastric acid hypersecretion in whom acid secretion status was monitored on lansoprazole, all were free of significant gastrointestinal infections on long-term follow-up.

TRIAL REGISTRATION

NCT00204373.

Clinical outcome using lansoprazole in acid hypersecretors with and without Zollinger-Ellison syndrome: a 13-year prospective study

BACKGROUND & AIMS

Unremitting gastric acid and pepsin hypersecretion causes serious persistent and relapsing lesions, but the natural history with medical treatment alone has not been well-defined. The aims of this study were to heal and prevent relapse of acid/peptic lesions during acid suppression and to analyze benefits and risks during long-term lansoprazole treatment.

METHODS

Sixty-seven patients (49 with Zollinger-Ellison syndrome [ZES], 18 without), with basal acid output (BAO) >15 mmol/h or >5 mmol/h if post-antrectomy (n = 9, all ZES), were treated with individually optimized doses of lansoprazole (7.5-450 mg/day; median, 75 mg/day) to reduce BAO to <5 mmol/h or <1 mmol/h post-antrectomy and underwent endoscopy every 3-6 months for up to 13 years (median, 6.25 years).

RESULTS

Before treatment, 94% had duodenal ulcer, 64% had esophagitis, 60% had 1 or more bleeding episodes, 13% had perforated ulcers, 90% had pain, 60% had heartburn, and 40%-48% had diarrhea, vomiting, and/or weight loss. Forty-seven patients (70%) remained symptom- and lesion-free, whereas 13 (20%) had mild, transient relapses, and 7 (10%) had more complicated relapses. Overall, symptoms were reduced 90+%; ulcer or esophagitis relapsed in 4.8% of patients/year, unrelated to Helicobacter pylori , whereas complications declined to <2%/y. Post-antrectomy ZES patients had 3.6-fold higher relapse rates than unoperated ZES patients (67% vs 18%, respectively). With BAO >5 mmol/h in intact patients, relative risk of relapse was 4.1, confidence interval 2.1-8.1, P < .001. Twenty patients died, 3 as a result of ZES (2 metastatic gastrinomas).

CONCLUSIONS

With individually optimized medical suppression of acid secretion, 90% of patients had good to excellent long-term outcomes without surgery, with an annualized total relapse rate of <5%.

Risk factors for esophagitis in extreme acid hypersecretors with and without Zollinger-Ellison syndrome

BACKGROUND & AIMS

Whereas severe duodenal ulcer is the hallmark of acid hypersecretion in Zollinger-Ellison syndrome (ZE) and similar states, the esophagus also is at high risk. We quantified the incidence of esophagitis and various risk factors that might contribute to it.

METHODS

Sixty-eight acid hypersecretors (basal acid output >15 mmol/h), 50 patients with ZE, and 18 patients without ZE with normal gastrin levels were studied by gastric analysis, serum gastrin levels, and endoscopy. In 44 of 68 patients, esophageal manometry was performed after the esophagus had healed.

RESULTS

Erosive esophagitis, grade 2 or worse, was found in 65%; an additional 15% had heartburn only, for a total reflux disease incidence of 80%. ZE accounted for 95% of severe esophagitis. Patients with and without esophagitis had the same high overnight fasting gastric residual volume and acidity, as well as basal and peak acid and pepsin outputs. However, patients with esophagitis had a lower median lower esophageal sphincter pressure (LESP) of 15.5 vs. 23 mm Hg in those without symptoms; the critical discriminator threshold was 16 mm Hg. Multivariate analysis further identified frequent vomiting and obesity as positive predictors of esophagitis, whereas Helicobacter pylori was a strong negative predictor (odds ratio, 0.16), possibly related to an elevated LESP in patients infected with H. pylori.

CONCLUSIONS

Erosive esophagitis is very common in acid hypersecretors. Identified risk factors that could promote abnormal esophageal exposure to the high acid and pepsin levels in our population of hypersecretors were vomiting, LESP < 16 mm Hg, and obesity, whereas H. pylori appeared to protect the esophagus not by reduced acid, but through an elevated LESP.

Vagal stimulation rapidly increases leptin secretion in human stomach

BACKGROUND & AIMS

Leptin production has been reported in the rat and in human stomach. It initiates intestinal nutrient absorption. In this study, we analyzed the effect of vagal stimulation on leptin release in the human stomach.

METHODS

We studied the secretion of gastric acid and leptin on stimulation with insulin (a stimulant of vagal pathways via hypoglycemia) and pentagastrin in 11 healthy men (normal endoscopy and normal histological gastric mucosa), 5 with previous highly selective vagotomy (HSV), and 6 without HSV. Fundic biopsies were performed for immunostaining of leptin.

RESULTS

There was no difference between the 2 groups with respect to age, body mass index, basal leptin (4.8 +/- 1.2 ng/15 minutes) and gastric acid (0.7 +/- 0.2 mmol/15 minutes) outputs. Leptin-immunoreactivity was found in the fundic glands, and its distribution and density were similar in 2 groups. Insulin caused a rapid (15-minute) increase in leptin output in men without HSV (31 +/- 9 ng/15 minutes), but not in those with HSV (7.7 +/- 3.2 ng/15 minutes). Insulin-stimulated gastric leptin was biphasic, with a rapid increase (15 minutes after injection) followed by a second steady and sustained increase (39.9 +/- 7.6 ng/15 minutes at 120 minutes after injection). Pentagastrin increased gastric leptin output in individuals with (30 +/- 4.9 ng/15 minutes) and without (26 +/- 3.2 ng/15 minutes) HSV. Insulin and pentagastrin did not modify plasma leptin, whatever HSV status.

CONCLUSIONS

Vagal stimulation of leptin release in the human stomach suggests that leptin is released during the cephalic phase of gastric secretion. Luminal leptin may be involved in vagus-mediated intestinal functions.

Minor effects of Helicobacter pylori on gastric secretion and dose of lansoprazole during long-term treatment in ZE and non-ZE acid hypersecretors

BACKGROUND

Helicobacter pylori infection may increase or decrease acid secretion and may augment proton pump inhibitor efficacy. Pepsin effects have not been reported. In Zollinger-Ellison syndrome (ZE) specifically, H. pylori has been reported to decrease acid.

AIM

To examine H. pylori effects on secretion and dose of medication in hypersecretors (basal acid output > 15 mmol/h) undergoing long-term treatment with individually optimized lansoprazole doses.

METHODS

Sixty-five patients (47 ZE and 18 non-ZE), treated for > 3 months to 10 years, were tested every 6 months with endoscopy, gastric analysis and serum gastrin.

RESULTS

Forty-three per cent were H. pylori-positive. Acid, pepsin and gastrin were not different between H. pylori-positive and H. pylori-negative patients before or during long-term lansoprazole treatment. Initially, H. pylori-positive patients required less lansoprazole than H. pylori-negative patients (68 +/- 6 vs. 96 +/- 8 mg/day), but after 3 years the doses converged (83 vs. 86 mg/day). The disappearance of H. pylori in 15 patients caused no significant changes in acid, pepsin, gastrin or lansoprazole dose in the following 4 years.

CONCLUSIONS

H. pylori had no significant initial or long-term physiological or potential clinical effects on acid or pepsin secretion or gastrin in these acid hypersecretors.

Long-term lansoprazole control of gastric acid and pepsin secretion in ZE and non-ZE hypersecretors: a prospective 10-year study

BACKGROUND

The majority of patients with Zollinger-Ellison syndrome require lifelong treatment with proton pump inhibitors.

AIMS

To determine the efficacy of lansoprazole control of acid and pepsin secretion over the long term in Zollinger-Ellison syndrome and non-Zollinger-Ellison syndrome hypersecretors.

METHODS

Sixty-three hypersecretors (basal acid output > 15 mmol/h), 46 Zollinger-Ellison syndrome and 17 non-Zollinger-Ellison syndrome, with a total history of 15.4 and 19.2 years, respectively, were entered into a long-term prospective study using lansoprazole. Sixty-one were studied every 3 months for 1 year and then every 3-6 months up to 10 years during lansoprazole treatment with endoscopy, serum gastrin and gastric analysis, measuring both basal and stimulated pH and acid and pepsin secretion. Doses were individually optimized and adjusted to keep the basal acid output at < 5 mmol/h in intact patients and < 1 mmol/h in antrectomized Zollinger-Ellison syndrome patients.

RESULTS

The dose of lansoprazole could not be predicted a priori from pre-treatment acid or pepsin output, serum gastrin, prior omeprazole dose or diagnosis or prior complications. The median dose was approximately 80 mg/day, with a wide range from 15 mg every other day to 360 mg/day, and generally stabilized by 12 months. However, as doses were adjusted over time for indications, almost half the patients required higher doses. With adjustments, the basal acid output was maintained in the target range in > 90% of intact patients and in 80% of antrectomized patients. Gastric juice pH increased from approximately 1.2 before therapy to > 3.4 during therapy. Serum gastrin in Zollinger-Ellison syndrome patients, after excluding five outliers, did not change over the course of therapy, but doubled in non-Zollinger-Ellison syndrome patients. There were no adverse events due to lansoprazole, and routine laboratory studies remained normal.

CONCLUSIONS

The dose of lansoprazole for hypersecretors cannot be predicted, and thus needs to be optimized empirically on an individual basis. With continued periodic adjustments, almost half the patients required increased doses, while safe dose reduction was possible in only one-quarter. When individually optimized, lansoprazole proved to be safe and effective in the control of secretion for the treatment of both Zollinger-Ellison syndrome and non-Zollinger-Ellison syndrome hypersecretors for up to 10 years.

Helicobacter pylori effects on gastritis, gastrin and enterochromaffin-like cells in Zollinger-Ellison syndrome and non-Zollinger-Ellison syndrome acid hypersecretors treated long-term with lansoprazole

BACKGROUND

Helicobacter pylori is said to cause atrophy of the gastric corpus and enterochromaffin-like cell proliferation in gastro-oesophageal reflux disease (GERD) patients treated long-term with a proton pump inhibitor.

AIMS

To determine the effect of H. pylori infection on gastritis, enterochromaffin-like cell density and hyperplasia, mucosal atrophy and serum gastrin in patients with gastric hypersecretion (basal acid output gt; 15 mmol/h) with either hypergastrinemia (Zollinger-Ellison syndrome) or normal gastrin (non-Zollinger-Ellison syndrome) before and during long-term treatment with lansoprazole.

METHODS

Lansoprazole was individually titrated to reduce basal acid output to < 5 mmol/h (< 1 mmol/h in post-surgical Zollinger-Ellison syndrome). Gastric corpus biopsies were obtained every 6 months before treatment and up to 8 years later.

RESULTS

H. pylori was present in corpus biopsies in approximately 50%, causing active gastritis which resolved rapidly in 15 subjects after elimination of H. pylori. Patchy mild/moderate corpus atrophy was present at entry in two and at the end in four out of 60 patients, one being H. pylori-positive. Intestinal metaplasia (< 10%) was seen in six isolated biopsies (1% of total). H. pylori did not affect serum gastrin, enterochromaffin-like cell density or hyperplasia. Enterochromaffin-like cell density was twice as high in Zollinger-Ellison syndrome as in non-Zollinger-Ellison syndrome patients (241 vs. 126 cells/mm2, P < 0.001). Enterochromaffin-like cells remained normal in the non-Zollinger-Ellison syndrome hypersecretors regardless of H. pylori status.

CONCLUSION

Corpus enterochromaffin-like cell increases were related to serum gastrin elevation, but neither H. pylori nor long-term treatment with lansoprazole alone or together had any effect on enterochromaffin-like cell density or hyperplasia. Corpus acute gastritis resulted from H. pylori infection, but did not result in mucosal atrophy despite long-term proton pump inhibitor treatment and promptly resolved with loss of H. pylori.

Gastric secretion of acid and pepsin in patients with esophageal stricture and appropriate controls

Most cases of esophageal stricture are associated with acid/peptic reflux esophagitis. While patients with strictures commonly have disordered lower esophageal sphincters and poor clearance and neutralization mechanisms, it is not known whether they also have abnormal gastric secretion. This study examined fasting, basal, and stimulated acid and pepsin secretion. With an endoscopic diagnosis of esophagitis, patients with stricture (< 12.5 mm) were matched for age, sex, concurrent gastrointestinal disease (duodenal ulcer, N = 9), Zollinger-Ellison syndrome (N = 6), and postgastric surgery state (N = 5), as well as the absence of ulcer disease (non-DU, N = 37). Fasting, basal, and pentagastrin-stimulated acid and pepsin secretion were measured. Overall, the 57 stricture patients had the same acid and pepsin secretion as their matched controls with esophagitis; the same was true for each of the subgroups (ZES, DU, non-DU, and postsurgical). Stricture patients weighed less and had a lower body mass index (P < 0.01). Patients with esophageal peptic stricture have the same acid and pepsin output as control patients matched for sex, age, background gastrointestinal disease, and the presence of esophagitis.

Gastric acid and pepsin secretion in patients with Barrett's esophagus and appropriate controls

The objective of this study was to determine whether gastric secretion of acid and pepsin is different in the subset of esophagitis patients who also have Barrett's esophagus. Basal and stimulated gastric secretions were studied for 1 hr in the unstimulated state and 1 hr after pentagastrin 6 microg/kg subcutaneous injection. Because Barrett's patients are predominantly male, the 30 patients were matched with patients who had esophagitis, but not Barrett's, for sex (26 men, 4 women) and age as well as for background gastrointestinal disease (duodenal ulcer in 10, no ulcer disease in 17 and Zollinger-Ellison hypersecretors in 3). Patients with Barrett's weighed more than controls (P < 0.05). Acid and pepsin output in the basal and stimulated state were no different in Barrett's and their appropriately matched controls. Overnight fasting residue--volume, pH, acid and pepsin concentrations, and bile content--were also alike. The severity of esophagitis or prevalence of esophageal ulcer or stricture was not different between those with and without Barrett's and in neither was the grade of esophagitis related to acid or pepsin output. It is concluded that Barrett's esophagus patients do not have gastric secretions different from appropriately matched controls with esophagitis alone. When present, esophagitis due to reflux in Barrett's epithelium should be treated on its merits by appropriate reduction of acid exposure.

Gastrin partially mediates insulin-induced acid secretion in dogs

A monoclonal antibody to gastrin was used to study the role of circulating gastrin in mediating insulin-stimulated acid output. On separate days, seven adult dogs with chronic gastric fistulas were pretreated i.v. with either 1) 7 mg of a gastrin monoclonal antibody (mAb 28.2); 2) 12.5 micrograms/kg atropine; 3) mAb 28.2 and atropine together; or 4) vehicle (0.1% canine serum albumin in 0.15 M NaCl). Thirty minutes later, acid secretion was stimulated by insulin (0.5 U/kg, i.v.), followed in 2 h by a 1-h infusion of histamine (40 micrograms/kg/h, i.v.). Acid output (mmol/15 min) in gastric effluent collected through the gastric fistula was determined by titration with 0.2 N NaOH to pH 7.0. Plasma gastrin was measured by radioimmunoassay. Plasma glucose was measured by a glucose oxidase method on an auto analyzer. Insulin induced a profound hypoglycemia (55 +/- 8 mg/dl) that coincided with a marked increase in acid output to 7.1 +/- 0.6 mmol/30 min by 45 min after injection. MAb 28.2 pretreatment and atropine pretreatment reduced insulin-stimulated acid outputs to 2.7 +/- 0.7 mmol/30 min and to 0.6 +/- 0.2 mmol/ 30 min, respectively. Acid output after combined pretreatment (0.5 +/- 0.2 mmol/30 min) was not significantly different than after atropine alone. Histamine-stimulated acid output (15.8 +/- 2.5 mmol/30 min) was not significantly reduced by any pretreatment. Insulin injection increased circulating gastrin concentrations to 32 +/- 7 fmol/ml, which was not significantly affected by atropine (39 +/- 9 fmol/ml). This study demonstrates that, in dogs, a significant part of insulin-stimulated acid secretion is mediated by circulating gastrin.