Bioassay and Radioimmunoassay of Plasma Gastrin in a Case of Zollinger-Ellison Syndrome

Fasting plasma gastrin levels were measured in a patient with the Zollinger-Ellison syndrome by both bioassay and radioimmunoassay. The level remained constant following total gastrectomy, but fell sharply following parathyroidectomy. Although the bioassay gave gastrin levels which were consistently 2 to 3 times higher than those obtained by radioimmunoassay, the values showed a similar trend. However, both methods gave almost identical results for the gastrin contents of antral mucosa and pancreatic tumour samples from the patient. It is suggested that biologically active gastrin-like substances not detectable by radioimmunoassay were present in the patient's plasma.     

Duodenal gastrinoma—clinical features and usefulness of selective arterial secretin injection test

Duodenal gastrinoma is recognized as a relatively common cause of Zollinger-Ellison syndrome, but its clinical and biological features are not well known. Here we report a case of duodenal gastrinoma with lymph node metastasis which was confirmed by pathology examinations. Hypergastrinemia and gastric acid hypersecretion were documented, but the secretin test showed negative results. An enlarged peripancreatic lymph node lying close to the pancreas head was the only positive finding on preoperative imaging studies. The results of the selective arterial secretin injection (SASI) test suggested that the primary tumor was located in the gastrinoma triangle. Finally, surgical exploration was carried out and a submucosal tumor, approximately 15mm in size, was detected by intraoperative palpation at the posterior wall of the proximal portion of the duodenum. Intraoperative pathology examination demonstrated metastases to regional lymph nodes. The present case calls attention to the unique features of duodenal gastrinomas, which differ from those of pancreatic origin: a highly malignant potential for its small size, and submucosal location in the proximal duodenum. The SASI test is recommended for assessing the location of a primary lesion if it cannot be identified by various conventional imaging studies. (Received Dec. 17, 1997; accepted Jan. 23, 1998)     

Diagnosis of Zollinger-Ellison syndrome: Increasingly difficult

In the present paper the increasing difficulty of diagnosis of Zollinger-Ellison syndrome (ZES) due to issues raised in two recent papers is discussed. These issues involve the difficulty and need to withdraw patients suspected of ZES from treatment with Proton Pump Inhibitors (omeprazole, esomeprazole, lansoprazole, rabeprazole, pantoprazole) and the unreliability of many gastrin radioimmunoassays. The clinical context of each of these important issues is reviewed and the conclusions in these articles commented from the perspective of clinical management.     

Gastric endocrine cell evolution in patients with Zollinger-Ellison syndrome

Evolution of gastrinoma tumoral mass, fasting serum gastrin concentrations, and gastric endocrine cells has been analyzed in 21 patients with the Zollinger-Ellison syndrome committed to long-term omeprazole treatment (up to 7.75 years, median 37 months). Gastrinoma growth was seen in eight patients. Significant increase in serum gastrin was only observed in the group of patients with gastrinoma growth. Fundic argyrophil cell densities were correlated with serum gastrin (r=0.68,P=0.002). Argyrophil and antral gastrin cell densities significantly increased during the survey, but increases were greater in the group with gastrinoma growth (respectively, +136% and +131%) than in the other group (respectively, +34% and +43%). Progression in the degree of argyrophil cell hyperplasia, noted qualitatively, was observed in 11 patients. Fundic carcinoids developed in three of these 11 patients, all three having multiple endocrine neoplasia type 1 (MEN 1). Positive linear individual correlations (r0.85) between argyrophil cell densities and corresponding durations of omeprazole treatment were found in nine of the 10 patients studied at least three times and who had a clear-cut increase in those cell densities. Thus, increase in serum gastrin and fundic argyrophil cell densities appeared closely associated with gastrinoma growth; however, duration of drug-induced hypochlorhydria may also affect cell proliferation.This work was supported by the Institut National de la Santé et de la Recherche Médicale (INSERM).     

Zollinger-Ellison phenotype in the absence of hypergastrinemia and islet-cell tumor

Patients with the Zollinger-Ellison syndrome are characterized by islet-cell tumors, striking gastric acid hypersecretion, and peptic ulcer disease. They often experience severe abdominal pain, diarrhea, and gastrointestinal bleeding with potentially life-threatening consequences. It is a rare syndrome caused by nonbeta cell islet-cell tumors (gastrinomas) located in or in proximity to the pancreas. These tumors freely secrete gastrin, a peptide hormone that serves as a powerful stimulant of gastric acid secretion. Exuberant secretion of gastrin from the gastrinomas produces severe gastric acid hypersecretion that often leads to impressive peptic ulcer disease and the constellation of symptoms listed above. We describe a patient presenting with clinical manifestations characteristic of the ZES with strikingly elevated gastric acid secretion, multiple ulcers in the first and second portions of the duodenum and diarrhea, but in absence of islet-cell tumor and/or hypergastrinemia.     

Effects of Helicobacter pylori infection on Zollinger-Ellison syndrome

Both Zollinger-Ellison syndrome (ZES) and Helicobacter pylori infection are major etiologic factors for peptic ulcer. The aim of this study was to investigate the effect of H. pylori infection on ZES with special reference to acid secretion. Sixteen patients with ZES were selected (median age, 59 years; range, 39–66 years; M/F, 9/7), and H. pylori status, ulcer location, gastric acid secretion, serum pepsinogen (PG) I and II concentrations, and PG I/II ratio were determined. The seroprevalence of H. pylori infection was 50%, whereas active H. pylori infection was seen in only 25% of the patients. Thirteen patients had duodenal ulcer (DU), 1 had gastric ulcer (GU), and 2 had both GU and DU. DU was seen in both H. pylori-positive and H. pylori-negative patients, whereas GU was found only in H. pylori-positive patients. Both basal and maximal acid outputs were significantly lower in H. pylori-positive patients than in H. pylori-negative patients (P < 0.05). Moreover, both serum PG I and the PG I/II ratio were significantly lower in H. pylori-positive patients than in H. pylori-negative patients. These results indicate that ZES is an independent risk factor for DU, but H. pylori infection may play some role in the development of GU in ZES. In patients with ZES, H. pylori infection may reduce both hypersecretion from parietal cells and PG I secretion from chief cells, and hyperacidity of the stomach in ZES may have eradicated H. pylori in some patients. Received: March 30, 2000 / Accepted: May 26, 2000     

Usefulness of selective arterial calcium injection test and secretin test in patients with insulinoma

Preoperatively, it is sometimes very difficult to localize pancreatic endocrine tumors by conventional imaging techniques. Insulinoma is often solitary and benign, but 10% of insulinomas are multiple and malignant. To perform a curative resection of insulinomas, it is important not to leave any tumor postoperatively. In patients with gastrinomas, the selective arterial secretin injection test has been demonstrated to be useful for the curative resection of gastrinomas, since this test tells us whether there is a gastrinoma in the area of interest. The principle of this test is based on the observation that gastrinomas promptly release gastrin when stimulated by secretin. Following a principle analogous to that underlying the secretin test, we have used calcium solution as a stimulant for insulinoma. This selective arterial calcium injection (SACI) test has been used in Kyoto and in National Institute in Health, Bethesda, USA, NIH since 1990. In three patients with insulinoma, curative resection was performed successfully, based on localization by the SACI test. For the differential diagnosis of insulinoma and B cell hyperplasia, we used the intravenous secretin test in 14 patients who had had episodes of hypoglycemia; the test was useful, showing 75% sensitivity and 100% specificity.     

A comparative evaluation of secretin bolus and secretin infusion as secretin provocation tests in the Zollinger-Ellison syndrome

GIH secretin bolus (2 CU/kg) and infusion (3 CU/kg/h) have been randomly compared in 9 ZES patients and 10 age-matched DU patients. Serum gastrin and gastric acid variations were studied before and after either mode of secretin administration in the same individuals. Plasma secretin modifications were monitored in parallel. In both ZES and DU, secretin bolus and infusion induced similar gastrin responses (maximal changes and integrated responses). However, secretin infusion had a greater effect on acid output than bolus: larger inhibition in DU and larger increase in ZES. The additive diagnostic value of gastric acid secretion study during a secretin provocation test, as already reported, favors the use of 3 CU/kg/h secretin infusion over that of 2 CU/kg secretin bolus.     

Prolonged hypergastrinemia does not increase the frequency of colonic neoplasia in patients with Zollinger-Ellison syndrome

Whereas considerable experimental evidence suggests chronic hypergastrinemia can increase the occurrence of colonic neoplasia, the risks in man remain unclear. Zollinger-Ellison syndrome (ZES) is associated with marked plasma elevation of all forms of gastrin and, because of its prolonged course, has been shown to be an excellent model disease to study the effects of chronic hypergastrinemia in man. To determine whether profound chronic hypergastrinemia affects the occurrence of colonic dysplasia and neoplasia, 97 consecutive patients with ZES were studied. All patients underwent colonoscopic examination to the cecum, and the location, size, and type of polyps/tumors were determined. The patients had a mean fasting gastrin level 31 times above normal and a mean disease duration of 10 years; 17/97 (18%) had adenomatous polyps, 67/97 (69%) no adenomatous polyps, and 2/97 (2%) had adenocarcinoma of the colon. These rates were within ranges reported in a number of colonoscopy and/or autopsy studies for asymptomatic controls. Stratification by age or gender, presence of MEN-I, tumor extent, and duration or degree of hypergastrinemia did not increase prevalence. This study shows that despite prolonged, profound hypergastrinemia, no increased rate of colonic neoplasia (polyps or cancer) was noted. These data suggest that the development of hypergastrinemia secondary to continuous use of H⁺,K⁺-ATPase inhibitors for as long as 10 years is unlikely to cause an increased risk of developing colonic neoplasia in man.     

Gastric luminal somatostatin secretion of normals and patients with pernicious anemia and with Zollinger-Ellison syndrome

We studied the release of gastric luminal somatostatin-like immunoreactivity (SLI) in response to a pentagastrin infusion (0.9 g/kg/hr, intravenous) in five normal volunteers, five patients with pernicious anemia, and two patients with Zollinger-Ellison syndrome. In addition, we studied the gastric luminal SLI secretion in response to a gastric luminal acid perfusion in two patients with pernicious anemia. Our results have shown that: (1)pentagastrin caused a parallel increase in luminal hydrogen ions and SLI release in normal volunteers; (2) Zollinger-Ellison patients had elevated basal acid and SLI levels that did not increase further with pentagastrin; (3) pentagastrin did not increase gastric acid or luminal SLI secretion in pernicious anemia patients; and (4) in pernicious anemia patients, a gastric luminal acid perfusion caused a significant increase in gastric luminal SLI over baseline values. In conclusion, gastric luminal hydrochloric acid appears to be a factor which stimulates the secretion of luminal SLI in human beings.This study was supported by the Gastroenterology Section Research Fund.This study was presented at the annual meeting of the American Gastroenterological Association in Chicago, Illinois, in May 1987.     

Progression of gastric enterochromaffin-like cells growth in Zollinger-Ellison syndrome and atrophic body gastritis patients

BACKGROUND: Enterochromaffin-like cell hyperplasia of the gastric body mucosa occurs in hypergastrinaemic conditions such as atrophic body gastritis and Zollinger-Ellison syndrome. However, the time course of change or factors involved are not known. AIMS: To compare the rate of change of enterochromaffin-like cell proliferation in patients with atrophic body gastritis and Zollinger-Ellison syndrome. PATIENTS: From a consecutive series of atrophic body gastritis and Zollinger-Ellison syndrome patients, studied at the time of first diagnosis, 10 atrophic body gastritis (4 with pernicious anaemia) and 14 Zollinger-Ellison syndrome (4 with multiple endocrine neoplasia type 1) patients were followed-up for a median time of 48 months. METHODS: At entry and during follow-up patients underwent: plasma gastrin determination, endoscopic sampling of body mucosa for qualitative assessment of enterochromaffin-like cell hyperplasia pattern and degree of glandular atrophy, qualitative and morphometric analyses of body mucosa endocrine cells. RESULTS: At time of diagnosis, enterochromaffin-like cell lesions were more severe in atrophic body gastritis than in Zollinger-Ellison syndrome. During follow-up, no significant variations were observed in gastrin values, enterochromaffin-like cell patterns and grade of body mucosa atrophy in atrophic body gastritis. In contrast, gastrin levels were significantly increased [median 1200 (235-2625) vs 1947 (225-5200) pg/ml; p<0.001)] as was total volume density of enterochromaffin-like cells [median 1.60 (0.53-4.06) vs 3.18 (1.35-21.13)% of mucosal epithelial component; (p<0.005)] in Zollinger-Ellison syndrome. Micronodular hyperplasia of enterochromaffin-like cells, present in only one patient at diagnosis, was observed in 8 Zollinger-Ellison syndrome patients at follow-up. CONCLUSIONS: These data suggest that the progression of enterochromaffin-like cell growth in human gastric mucosa requires an increase of and/or a prolonged exposure to severe hypergastrinaemia.     

Stereologic Investigations of Human Gastric Mucosa: II. Oxyntic Mucosa from Patients with Zollinger-Ellison Syndrome

Biopsy specimens from the oxyntic mucosa were obtained on 210 occasions from 76 patients with the Zollinger-Ellison syndrome (ZES) before and during omeprazole treatment. One-micrometer sections were examined by light microscopy, and in 5% linear hyperplasia of endocrine cells was observed. Morphometry was carried out in 91 of the specimens and showed a significant increase of the mean endocrine cell density in comparison with both young, healthy subjects and patients suffering from active peptic ulcer disease (PUD). No metaplasia, dysplasia, or neoplasia was detected in patients with ZES, and the mean mucosal thickness and parietal cell density remained normal. The parietal cells often displayed endosome-like structures, and occasionally there were Ungulate cytoplasmic projections into the gland lumen. Electron microscopic morphometry was carried out in specimens from nine patients with ZES and did not show any significant differences in the parietal cells in comparison with healthy subjects.     

Multiple gastrinoma successfully resected with the aid of intraoperative arterial secretin injection test

Since gastrinoma is likely to develop in multiple sites, we should pay special attention to the removal of all daughter tumors, as well as the main tumor, during surgery for this disease. In a 24-year-old woman with pituitary prolactinoma, multiple gastrinomas were detected in a limited area of the pancreaticoduodenal region by preoperative imaging techniques, selective arterial secretin injection (SASI) test, and intraoperative inspection using ultrasonography. A pancreatoduodenectomy was performed, and it was intraoperatively confirmed that the serum gastrin concentration in the portal vein had decreased from 753 to 83 pg/ml (normal,<120pg/ml). However, intraoperative SASI test for the remnant pancreas showed a positive response, which prompted us to perform a histological examination of frozen sections obtained from the body and tail of the pancreas, despite the normal appearance. Many islet cell microtumors were discovered, and the remnant pancreas was completely removed. Postoperativelly, all of the tumors were immunohistochemically proven to be microgastrinomas. The patient is still disease-free, 2 years after the surgery, with a serum gastrin level of less than 30pg/ml. This report stresses the role of the intraoperative SASI test in preventing residual microgastrinomas before closure of the abdomen.     

High-dose calcium stimulation test in a case of insulinoma masquerading as hysteria

It is reported that some cases with insulinoma present with neuropsychiatric symptoms and are often misdiagnosed as psychosis. Here we report a case of insulinoma masquerading as hysteria, whose final diagnosis could be made using high-dose calcium stimulation test. A 28-yr-old woman was referred presenting with substupor, mutism, mannerism, restlessness, and incoherence. Laboratory examinations revealed hypoglycemia (33 mg/dL) and detectable insulin levels (9.7 μU/mL), suggesting the diagnosis of insulinoma. However, neither imaging studies nor selective arterial calcium injection (SACI) test with a conventional dose of calcium (0.025 mEq/kg) indicated the tumor. High-dose calcium injection (0.05 mEq/kg) evoked insulin secretion when injected into superior mesenteric artery. A solitary tumor in the head of the pancreas was resected, and her plasma glucose returned to normal. Postoperatively, iv injection of secretin resulted in a normal response of insulin, which was not found preoperatively. This case suggests the usefulness of the SACI test with high-dose of calcium in the case of insulinoma when the standard dose fails to detect such a tumor.     

Surgical management of Zollinger-Ellison syndrome: Classical considerations and current controversies

Zollinger-Ellison syndrome(ZES) is characterized by gastric acid hypersecretion causing severe recurrent acid-related peptic disease. Excessive secretion of gastrin can now be effectively controlled with powerful proton pump inhibitors,but surgical management to control gastrinoma itself remains controversial.Based on a thorough literature review, we design a surgical algorithm for ZES and list some significant consensus findings and recommendations:(1) For sporadic ZES, surgery should be routinely undertaken as early as possible not only for patients with a precisely localized diagnosis but also for those with negative imaging findings. The surgical approach for sporadic ZES depends on the lesion location(including the duodenum, pancreas, lymph nodes,hepatobiliary tract, stomach, and some extremely rare sites such as the ovaries,heart, omentum, and jejunum). Intraoperative liver exploration and lymphadenectomy should be routinely performed;(2) For multiple endocrine neoplasia type 1-related ZES(MEN1/ZES), surgery should not be performed routinely except for lesions 2 cm. An attempt to perform radical resection(pancreaticoduodenectomy followed by lymphadenectomy) can be made. The ameliorating effect of parathyroid surgery should be considered, and parathyroidectomy should be performed first before any abdominal surgery for ZES; and(3) For hepatic metastatic disease, hepatic resection should be routinely performed. Currently, liver transplantation is still considered an investigational therapeutic approach for ZES. Well-designed prospective studies are desperately needed to further verify and modify the current considerations.     

Effect of secretin on basal- and glucose-stimulated insulin secretion in man

Summary Plasma immunoreactive secretin and insulin concentrations were measured in fasting normal humans after intraduodenal infusions of hydrochloric acid, isotonic or hypertonic glucose. The effect of intraduodenal acidification or intravenous bolus injections of secretin on plasma insulin concentrations during infusions of glucose was also examined. The intraduodenal glucose load did not cause an increase in plasma secretin concentrations. Secretin concentrations rose after acid both in the fasting state and during infusions of glucose. A concomitant rise in insulin levels was however only observed during infusions of glucose. Intravenous injection of secretin in a dose which mimicked the response to intraduodenal acidification was without effect on the glucose-stimulated insulin release, while a 30 times higher dose caused a highly significant augmentation of the insulin release. The insulin response pattern to this high dose of secretin differed completely from that observed after intraduodenal infusion of acid. It is concluded and confirmed that the stimulating effect of secretin on insulin secretion is pharmacological and that secretin plays no significant role in the entero-insular axis.     

Mechanism for increase of gastrin release by secretin in Zollinger-Ellison syndrome

In patients with Zollinger-Ellison syndrome, serum gastrin level is increased by secretin and is decreased by somatostatin. To elucidate the cellular mechanism for these actions, we investigated the direct effects of secretin and somatostatin on dispersed gastrinoma cells from a patient with Zollinger-Ellison syndrome. In the presence of 3-isobutyl-1-methylxanthine, secretin significantly stimulated gastrin release from dispersed gastrinoma cells, which was inhibited by somatostatin. In the presence of guanosine 5'-triphosphate, furthermore, secretin enhanced adenylate cyclase activation in the membranes from these cells, and this activation was reduced by somatostatin, whereas neither secretin nor somatostatin affected inositol phospholipid turnover. On the other hand, removal of guanosine 5'-triphosphate from incubation medium abolished both the stimulatory effect of secretin and the inhibitory effect of somatostatin on adenylate cyclase activation. Furthermore, pertussis toxin pretreatment reversed the ability of somatostatin to inhibit secretin-induced increase in gastrin release and activation of adenylate cyclase. Thus, in this gastrinoma patient, secretin and somatostatin appeared to act directly on gastrinoma cells to stimulate and inhibit gastrin secretion, respectively, by modulating adenylate cyclase activation, probably via guanine nucleotide-binding proteins.