Izumi Komoto

Changing Treatment Strategy for Gastrinoma in Patients with Zollinger-Ellison Syndrome

We overviewed the recent development of curative surgery for gastrinoma that has been rapidly improved since the development of new localization techniques, especially the selective arterial secretagogue injection test (SASI test) and somatostatin receptor scintigraphy (SRS). A number of new pathological findings of gastrinomas in patients with Zollinger-Ellison syndrome have been accumulated in accordance with the increase of curative resection of gastrinomas, and these new findings also have contributed to the progress of the treatment strategy for grastrinomas.

Preliminary results of a Japanese nationwide survey of neuroendocrine gastrointestinal tumors

BackgroundWe conducted a nationwide survey to estimate the incidence of neuroendocrine gastrointestinal tumors (NETs) newly diagnosed in Japan from 2002 through 2004.MethodsData on 1541 patients, 514 pancreatic endocrine tumors (PETs) and 1027 gastrointestinal carcinoids (GICs), were collected and analyzed.ResultsNonfunctioning tumors (NF-PET) constituted 47.7% of PETs. Next in frequency were insulinoma (31.7%) and gastrinoma (8.6%). Malignancy was frequent in NF-PETs (46.1%) and gastrinomas (45.5%), but only 7.4% of insulinomas were malignant. The incidence of multiple endocrine neoplasia type-1 associated with PETs was 7.4%. The incidence of GICs was 28.8%, 5.2%, and 66.0% in foregut, midgut, and hindgut, respectively. Carcinoid syndrome and metastases were observed in only 1.7% and 5.6% of GICs, respectively.ConclusionsThe incidence of NETs in Japan was clarified by this preliminary study. Comparatively large differences in GICs between Japan and Western nations were present with regard to the location, symptomatic status, and prevalence of malignancy.

Expression of the gene for a membrane-bound fatty acid receptor in the pancreas and islet cell tumours in humans : evidence for GPR40 expression in pancreatic beta cells and implications for insulin secretion

Aims/hypothesisG protein-coupled receptor 40 (GPR40) is abundantly expressed in pancreatic beta cells in rodents, where it facilitates glucose-induced insulin secretion in response to mid- to long-chain fatty acids in vitro. However, GPR40 gene expression in humans has not been fully investigated, and little is known about the physiological and pathophysiological roles of GPR40 in humans. The aim of this study, therefore, was to examine GPR40 expression and its clinical implications in humans.Methods: GPR40mRNA expression in the human pancreas, pancreatic islets and islet cell tumours was analysed using TaqMan PCR.Results: GPR40mRNA was detected in all human pancreases collected intraoperatively. It was enriched approximately 20-fold in isolated islets freshly prepared from the pancreases of the same individuals. The estimated mRNA copy number for the GPR40 gene in pancreatic islets was comparable to those for genes encoding sulfonylurea receptor 1, glucagon-like peptide 1 receptor and somatostatin receptors, all of which are known to be expressed abundantly in the human pancreatic islet. A large amount of GPR40 mRNA was detected in insulinoma tissues, whereas mRNA expression was undetectable in glucagonoma or gastrinoma. The GPR40 mRNA level in the pancreas correlated with the insulinogenic index, which reflects beta cell function (r=0.82, p=0.044), but not with glucose levels during the OGTT, the insulin area under the OGTT curve or the index for the homeostasis model assessment of insulin resistance (HOMA-IR).Conclusions/interpretationThe present study provides evidence for GPR40 gene expression in pancreatic beta cells and implicates GPR40 in insulin secretion in humans.

Biochemically curative surgery for gastrinoma in multiple endocrine neoplasia type 1 patients

AIM To search for the optimal surgery for gastrinoma and duodenopancreatic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1. METHODS Sixteen patients with genetically confirmed multiple endocrine neoplasia type 1 (MEN 1) and Zollinger-Ellison syndrome (ZES) underwent resection of both gastrinomas and duodenopancreatic neuroendocrine tumors (NETs) between 1991 and 2009. For localization of gastrinoma, selective arterial secretagogue injection test (SASI test) with secretin or calcium solution was performed as well as somatostatin receptor scintigraphy (SRS) and other imaging methods such as computed tomography (CT) or magnetic resonance imaging (MRI). The modus of surgery for gastrinoma has been changed over time, searching for the optimal surgery: pancreaticoduodenectomy (PD) was first performed guided by localization with the SAST test, then local resection of duodenal gastrinomas with dissection of regional lymph nodes (LR), and recently pancreas-preserving total duodenectomy (PPTD) has been performed for multiple duodenal gastrinomas. RESULTS Among various types of preoperative localizing methods for gastrinoma, the SASI test was the most useful method. Imaging methods such as SRS or CT made it essentially impossible to differentiate functioning gastrinoma among various kinds of NETs. However, recent imaging methods including SRS or CT were useful for detecting both distant metastases and ectopic NETs; therefore they are indispensable for staging of NETs. Biochemical cure of gastrinoma was achieved in 14 of 16 patients (87.5%); that is, 100% in 3 patients who underwent PD, 100% in 6 patients who underwent LR (although in 2 patients (33.3%) second LR was performed for recurrence of duodenal gastrinoma), and 71.4% in 7 patients who underwent PPTD. Pancreatic NETs more than 1 cm in diameter were resected either by distal pancreatectomy or enucleations, and no hepatic metastases have developed postoperatively. Pathological study of the resected specimens revealed co-existence of pancreatic gastrinoma with duodenal gastrinoma in 2 of 16 patients (13%), and G cell hyperplasia and/or microgastrinoma in the duodenal Brunners gland was revealed in all of 7 duodenal specimens after PPTD. CONCLUSION Aggressive resection surgery based on accurate localization with the SASI test was useful for biochemical cure of gastrinoma in patients with MEN 1.

New Pancreas-preserving Total Duodenectomy Technique

Pancreas-preserving total duodenectomy (PPTD) was first described by Chung et al. in 1994. Since then, several surgeons have used PPTD to treat diseases that involve the duodenum diffusely but not the head of the pancreas, mostly familial adenomatous polyposis (FAP). The PPTD method has been changed in each report and seems to have improved over time. We performed PPTD on three patients with different diseases-one with intestinal hemorrhage due to small intestinal amyloidosis; another with numerous duodenal gastrinomas in a patient with multiple endocrine neoplasia type 1 (MEN-1) and Zollinger-Ellison syndrome (ZES); and the third with numerous duodenal polyposis and FAP-using a new method that is simpler and safer than those previously reported. When resecting the whole duodenum, we performed mucosectomy of the major papillar portion and saved the structure of the major papilla. After an approximately 8 mm long sphincteropapillotomy, the opened major papilla was anastomosed to an incisional opening of the small intestine. The orifice of the main pancreatic duct (MPD) was stented by a catheter, and the MPD was kept intact under direct vision during the operative procedures. The head of the pancreas was fixed with the small intestine by interrupted 4-0 silk sutures. Reconstruction of the alimentary tract was performed after either the Billroth I or the Billroth II method. This is the first report of PPTD in which the entire MPD was preserved to simplify the biliopancreatic-ductal reconstruction.

Multiple endocrine neoplasia type 1 in Japan: establishment and analysis of a multicentre database

Objective  Multiple endocrine neoplasia type 1 (MEN1) is less well recognized in Asian countries, including Japan, than in the West. The clinical features and optimal management of MEN1 have yet to be clarified in Japan. The aim of this study was to clarify the clinical features of Japanese patients with MEN1.

Intravenous Calcium Injection Test Is a Novel Complementary Procedure in Differential Diagnosis for Gastrinoma

Abstract The current study evaluated efficacy of the intravenous calcium injection test as a new diagnostic approach to clarify the existence of gastrinoma, which often goes undetected with routine testing. Twenty-six patients with hypergastrinemia were studied. For the calcium injection test, blood samples were taken from 12 patients with hypergastrinemia (HG), and three healthy volunteers, and one patient with nonfunctioning endocrine tumor in the pancreas (control). We compared results of the calcium injection test with those of the secretin test and the selective arterial secretagogue injection (SASI) test. The SASI test with secretin was performed in 24 of 26 patients with hypergastrinemia, including 22 of 24 patients with Zollinger-Ellison syndrome (ZES). Accuracy in the diagnosis of tumor localization by the SASI test was 95% (21 of 22) in ZES patients. The secretin test was negative in 3 of 21 patients with ZES (14%). Either the secretin test or the SASI test was positive in 22 of 23 patients (96%). The calcium injection test was administered to 12 patients in the HG group and 4 controls. The HG group showed significantly higher serum gastrin levels than those of the control group in the calcium injection test. Eight of 10 ZES patients (80%) had a positive calcium injection test. We could diagnose gastrinomas in 100% of ZES patients by either the calcium injection test or the secretin test. We have thus confirmed the efficacy of the intravenous calcium injection test in the diagnosis of gastrinoma. The calcium injection test could become an adjunct in the diagnosis of gastrinoma, which often goes undetected with routine testing.

Curative resection of microgastrinomas based on the intraoperative secretin test

The intravenous secretin injection test (secretin test) has been used for the differential diagnosis of gastrinoma. In this study we report that the intraoperative secretin test (IOS test) is also useful for determining the extent of curability in patients with Zollinger-Ellison syndrome (ZES). Twelve patients with ZES underwent surgical exploration and the IOS test. The results of the IOS test were obtained by rapid radioimmunoassay of the serum gastrin level (IRG) within 60 minutes. The test was diagnosed as negative when the maximum increase of serum IRG was less than 80 pg/ml and also less than 20% of the basal serum IRG level. Three of the twelve patients underwent pancreatoduodenectomy (PD), and two patients underwent distal pancreatectomy. Extirpation of duodenal tumors with dissection of regional lymph nodes was performed in seven patients. In two of the seven patients the IOS test remained positive after extirpation of the duodenal tumors and the dissection of regional lymph nodes. In one patient PD was performed on the basis of the positive results, and the IOS test became negative after PD. In the other patient, two tiny metastatic liver tumors were identified and were resected, but the IOS test did not become negative. We closed the abdomen in 11 patients when we obtained negative results from the IOS test. The results of the IOS test were almost identical to the data obtained by the standard assay postoperatively. The serum IRG levels of all but one patient fell to the normal level, and the secretin test became negative postoperatively. The IOS test is thus useful and indispensable for curative resection of microgastrinomas in patients with ZES.

Clinicopathological Significance of Human Macrophage Metalloelastase Expression in Esophageal Squamous Cell Carcinoma

Objective: Human macrophage metalloelastase is referred to as matrix metalloproteinase (MMP-12), its function in tumors is contradictory. The current study was undertaken to investigate the role of MMP-12 in esophageal squamous cell carcinoma (SCC). Patients and Methods: We analyzed the levels of MMP-12 mRNA expression in 67 patients with primary esophageal SCC by Northern blot analysis and the tissues were subjected to in situ hybridization analysis for MMP-12. Immunohistochemical staining was performed to detect the macrophages infiltrated in esophageal SCCs. Results: MMP-12 mRNA was detected in 27 of 67 esophageal SCC samples by Northern blot analysis. In situ hybridization and immunohistochemical staining revealed that MMP-12 mRNA signals are located mainly in tumor cells. The frequency of lymph node metastasis was significantly higher in the MMP-12-positive (MMP-12(+)) subgroup than MMP-12-negative (MMP-12(–)) subgroup (p < 0.05); furthermore, invasion was significantly deeper in the MMP- 12(+) subgroup than in the MMP-12(–) subgroup (p < 0.01). MMP-12 mRNA was inversely correlated with prognosis (p < 0.05). However, Cox multivariate analysis revealed that upregulation of MMP-12 was not related to prognosis. Conclusions: MMP-12 gene expression was associated with the progression of esophageal SCC; however, it was not an independent prognostic factor.

Human gastrinoma cells express calcium-sensing receptor.

The intravenous calcium injection test has been reported to be useful for the diagnosis of gastrinoma. However, the mechanism underlying calcium-evoked gastrin release is not fully understood. We investigated the mechanism of calcium-stimulated gastrin release from gastrinoma cells in vitro with a particular focus on the calcium-sensing receptor (CaR). Human gastrinoma cells were taken from mechanically minced gastrinoma tissues obtained at surgery. In the perifusion system, high [Ca2+]o induced gastrin release from gastrinoma cells. As [Ca2+]o increased, [Ca2+]i rapidly increased, as monitored by fluorometry. The response was not inhibited by nifedipine, a blocker of the voltage-dependent calcium channel. Reverse transcriptase-polymerase chain reaction and subsequent Southern blot hybridization revealed the presence of the CaR gene in human gastrinoma tissues. Moreover, the expression of CaR in gastrinoma tissues was confirmed by immunohistochemistry. Our results demonstrated that CaR was expressed in human gastrinoma cells and could be involved in the mechanism of calcium-evoked gastrin release.