The Morphologic Spectrum of Gastric Type 1 Enterochromaffin-Like Cell Neuroendocrine Tumors.

Although most well-differentiated gastric neuroendocrine tumors (gNETs) arise from enterochromaffin-like (ECL) cells in patients with autoimmune metaplastic atrophic gastritis (AMAG), the morphologic spectrum of these type 1 ECL-cell gNETs is not well defined. The extent of metaplastic progression in the background mucosa of AMAG patients with gNETs is likewise unclear. Here we report the histomorphology of 226 gNETs, including 214 type 1 gNETs (78 cases from 50 AMAG patients) pooled from a population with high AMAG prevalence. Most type 1 gNETs were ≤1.0 cm, of low grade, and multifocal, consistent with the results of previous reports. However, a high proportion (70/214, 33%) displayed unusual gNET morphologies not previously appreciated in AMAG patients. Unlike other type 1 gNETs with conventional neuroendocrine tumor morphologies, unconventional type 1 gNETs displayed cribriform networks of atrophic cells embedded within myxoid matrix (secretory-cribriform variant, 59%), sheets of deceptively bland discohesive cells resembling inflammatory infiltrates (lymphoplasmacytoid variant, 31%), or wreath-like arrangements of columnar cells wrapped around collagenous cores (pseudopapillary variant, 14%). Another unusual feature was that unconventional gNETs grew laterally within the mucosa (50/70, 71%) and were only rarely sampled from the submucosa (3/70, 4%). These features also differed from the conspicuous radial nodules (99/135, 73%) and frequent submucosal involvement (57/135, 42%) observed for conventional gNETs (P < .0001). Irrespective of morphology, type 1 gNETs were nearly always detected at first AMAG diagnosis (45/50, 90%) and tended to persist thereafter (34/43, 79%), despite similar clinical symptoms and laboratory values between AMAG patients with gNETs and those without. However, unlike AMAG patients without gNETs (n = 50), the background mucosa in patients with gNETs (n = 50) had already progressed to the morphologic equivalent of end-stage metaplasia (P < .0001). This included diffuse loss of parietal cells (92% vs 52%), complete intestinal metaplasia (82% vs 40%), and pancreatic metaplasia (56% vs 6%). Thus, type 1 ECL-cell gNETs are morphologically heterogeneous with a high prevalence of unconventional gNET morphologies. They tend to present silently at first AMAG diagnosis as multifocal lesions that persist within fields of mature metaplasia.

Early autoimmune gastritis presenting with a normal endoscopic appearance.

This report describes a patient with early-stage autoimmune gastritis (AIG) presenting with a normal endoscopic appearance. A 66-year-old man with autoimmune thyroiditis was suspected of having AIG because of a previous history of vitamin B12 deficiency when receiving steroid therapy for interstitial pneumonia 5 years earlier. At presentation, he tested positive for anti-parietal cell antibody (1:320) and anti-intrinsic factor antibody, but not for vitamin B12 deficiency. His gastrin level was elevated (338 pg/mL), but his pepsinogen (PG) I level (56.1 ng/mL) and PGI/PGII ratio (7.6) were normal. Endoscopically, neither atrophic nor inflammatory changes were observed. Histopathologic examination, however, showed mild atrophic changes with dense lymphocytic infiltration in the deep lamina propria and focal destruction of parietal cells in the greater curvature of the corpus. PGI-positive/MUC6-positive pseudo-pyloric metaplasia was observed in the area from which H+/K+-ATPase-positive parietal cells had disappeared. Chromogranin A immunostaining showed linear hyperplasia of enterochromaffin-like cells. By contrast, atrophic changes were not evident in the lesser curvature of the corpus, except for mild lymphocytic infiltration around and into the fundic glands. These serological and histopathological findings suggested that the patient had early-stage AIG with a normal endoscopic appearance.

A case of enterochromaffin-like cell neuroendocrine tumor associated with parietal cell dysfunction which was successfully treated with somatostatin analogue.

We report here a case of a 62-year-old woman with multiple gastric enterochromaffin-like cell neuroendocrine tumor caused by hypergastrinemia due to parietal cell dysfunction that was successfully treated with somatostatin analogue. Esophagogastroduodenoscopy revealed several G1 neuroendocrine tumors, 10 mm in diameter, in the body of the stomach. No evidence of autoimmune gastritis, Helicobacter pylori infection, neuroendocrine neoplasia type 1, or Zollinger-Ellison syndrome was identified. The pattern of immunohistochemical staining of the background gastric mucosa was suggestive of parietal cell dysfunction. She was treated with long-acting release octreotide acetate. Complete response was confirmed after 9 months and was maintained for 22 months.

Enterochromaffin-like Cell Hyperplasia-Associated Gastric Neuroendocrine Tumors May Arise in the Setting of Proton Pump Inhibitor Use.

CONTEXT.­: Hypergastrinemia states such as achlorhydria from gastric mucosal atrophy or a gastrin-producing tumor in humans have been associated with the development of enterochromaffin-like (ECL) cell hyperplasia and gastric neuroendocrine tumors (GNETs). Whether drugs that can elevate serum gastrin levels, such as proton pump inhibitors (PPIs), can produce the same tissue effect is not known, and there is no concrete evidence linking the use of PPIs to GNETs outside animal models and case reports. OBJECTIVE.­: To explore the clinicopathologic association for GNETs of presumed ECL cell origin that cannot be reliably placed into any of the 3 established categories currently recognized by the World Health Organization. DESIGN.­: This is a retrospective clinicopathologic study of GNETs in the body/fundus during a period of 15 years (2005-2019). RESULTS.­: Of a total of 87 cases, 57 (65.5%) were associated with atrophic gastritis, 2 (2.3%) were associated with Zollinger-Ellison syndrome, and 28 (32.2%) were unclassified. Of the latter, 11 were consistent with true sporadic/type 3 GNETs, while 17 had background mucosal changes of parietal cell and ECL cell hyperplasia but without underlying detectable gastrinoma, and 88.2% (15 of 17) of patients from this group had documented long-term PPI use. This subtype of GNETs was more commonly multifocal and of higher grade (P = .03) than "true" sporadic GNETs. CONCLUSIONS.­: A subset of GNETs arises in the background of gastric mucosal changes suggestive of hypergastrinemia, but without underlying gastrinoma, and could be linked to long-term PPI use.

A case of autoimmune gastritis with fundic gland polyp-like pseudopolyps presenting with nodular enterochromaffin-like cell hyperplasia.

Pseudopolyps, a type of remnant oxyntic mucosa on a background of corpus-restricted mucosal atrophy, are a characteristic endoscopic finding in autoimmune gastritis (AIG). Linear or nodular enterochromaffin-like (ECL) cell hyperplasia, a characteristic histopathological finding of AIG, is not generally found in pseudopolyps. We report a case of AIG with fundic gland polyp (FGP)-like pseudopolyps containing nodular ECL cell hyperplasia. A 64-year-old man underwent esophagogastroduodenoscopy, which revealed atrophic changes limited to the corpus, with a normal antrum. The greater curvature was less atrophic than the lesser curvature. Sessile or semipedunculated polypoid lesions were observed on the greater curvature and on the anterior and posterior walls of the corpus. The polypoid lesions resembled FGPs, although some were larger than FGPs generally are. Histologically, non-atrophic fundic glands with parietal cell pseudohypertrophy were observed in the upper regions of the polypoid lesions. By contrast, at the base of the lesions, where linear and nodular ECL cell hyperplasia was identified by immunohistochemical staining, destruction of fundic glands with lymphocytic infiltration, loss of parietal cells, and pseudopyloric metaplasia was observed. Anti-parietal cell antibody positivity and hypergastrinemia confirmed the diagnosis of AIG with pseudopolyps. FGP-like pseudopolyps can, therefore, be present with nodular ECL cell hyperplasia in AIG.

Influence of hypergastrinemia secondary to long-term proton pump inhibitor treatment on ECL cell tumorigenesis in human gastric mucosa.

Proton pump inhibitor (PPI) therapy causes hypergastrinemia, which could promote the development and progression of neuroendocrine tumors (NETs). Concerns have been raised about the safety of long-term PPI use due to a possible increased risk of NETs. This study aimed to investigate the association between hypergastrinemia and the risk of NETs. Twenty outpatients presenting with serum gastrin levels greater than 400 pg/mL after long-term PPI treatment were registered in this study. Immunohistochemical analyses for chromogranin A (CgA), Ki67, gastrin and CCK/B gastrin receptor (CCKBR) were performed, and positive cell numbers were counted. There were no NET or gastric epithelial neoplasia cases observed among any of the 20 patients examined throughout the PPI treatment period. Histologically, ECL cell hyperplasia were shown in all patients. However, no relationship was found between serum gastrin levels and the number of CgA positive ECL cells. There was also no relationship between serum gastrin levels and the proportion of Ki67 positive cells or the density of CCKBR positive cells. The data indicate no relationship may exist between NETs and hypergastrinemia secondary to PPI treatment in patients having no, or mild, atrophic gastritis.

Clinical consequences of controversies in gastric physiology.

Studies on the regulation of gastric acid secretion started more than 100 years ago at an early phase of experimental physiology. In nearly the whole last century there were disputes about the interpretation of the findings: the interaction between the three principle gastric acid secretagogues acetylcholine, gastrin and histamine, the cell producing the relevant histamine which turned out to be the ECL cell, the ability of the ECL cell to divide and thus develop into tumours, the classification of gastric carcinomas and the mechanism for Helicobacter pylori carcinogenesis. The elucidation of the central role of the ECL cell and thus its main regulator, gastrin, solve all these controversies, and gives a solid base for handling upper gastrointestinal diseases.

Hypergastrinemia Expands Gastric ECL Cells Through CCK2R+ Progenitor Cells via ERK Activation.

BACKGROUND & AIMS: Enterochromaffin-like (ECL) cells in the stomach express gastrin/cholecystokinin 2 receptor CCK2R and are known to expand under hypergastrinemia, but whether this results from expansion of existing ECL cells or increased production from progenitors has not been clarified. METHODS: We used mice with green fluorescent protein fluorescent reporter expression in ECL cells (histidine decarboxylase [Hdc]-green fluorescent protein), as well as Cck2r- and Hdc-driven Tamoxifen inducible recombinase Cre (Cck2r-CreERT2, Hdc-CreERT2) mice combined with Rosa26Sor-tdTomato (R26-tdTomato) mice, and studied their expression and cell fate in the gastric corpus by using models of hypergastrinemia (gastrin infusion, omeprazole treatment). RESULTS: Hdc-GFP marked the majority of ECL cells, located in the lower third of the gastric glands. Hypergastrinemia led to expansion of ECL cells that was not restricted to the gland base, and promoted cellular proliferation (Ki67) in the gastric isthmus but not in basal ECL cells. Cck2r-CreERT2 mice marked most ECL cells, as well as scattered cell types located higher up in the glands, whose number was increased during hypergastrinemia. Cck2r-CreERT2+ isthmus progenitors, but not Hdc+ mature ECL cells, were the source of ECL cell hyperplasia during hypergastrinemia and could grow as 3-dimensional spheroids in vitro. Moreover, gastrin treatment in vitro promoted sphere formation from sorted Cck2r+Hdc- cells, and increased chromogranin A and phosphorylated- extracellular signal-regulated kinase expression in CCK2R-derived organoids. Gastrin activates extracellular signal-regulated kinase pathways in vivo and in vitro, and treatment with the Mitogen-activated protein kinase kinase 1 inhibitor U0126 blocked hypergastrinemia-mediated changes, including CCK2R-derived ECL cell hyperplasia in vivo as well as sphere formation and chromogranin A expression in vitro. CONCLUSIONS: We show here that hypergastrinemia induces ECL cell hyperplasia that is derived primarily from CCK2R+ progenitors in the corpus. Gastrin-dependent function of CCK2R+ progenitors is regulated by the extracellular signal-regulated kinase pathway.

Serum chromogranin A level continuously rises with the progression of type 1 diabetes, and indicates the presence of both enterochromaffin-like cell hyperplasia and autoimmune gastritis.

AIMS/INTRODUCTION: The relationship of chromogranin A (CgA) levels above the normal range with various outcomes, such as glycated hemoglobin levels, enterochromaffin-like cell hyperplasia and autoimmune gastritis, was investigated in type 1 diabetes patients with special regard to the progression of comorbidities. MATERIALS AND METHODS: A cohort study on 153 type 1 diabetes patients was carried out with a prospective branch on clinical and laboratory data, and a retrospective branch on histological data obtained by gastroscopy. RESULTS: Patients with CgA levels above the upper limit of the normal range (n = 28) had significantly higher glycated hemoglobin levels (P = 0.0160) than those with CgA in the normal range (n = 125). The correlation between CgA and glycated hemoglobin was significant (P < 0.0001), but weak (R = +0.32). A slight, but steady elevation (P = 0.0410) in CgA level was observed to co-vary with the duration of type 1 diabetes. Enterochromaffin-like cell hyperplasia and autoimmune gastritis was significantly more frequent (P = 0.0087 for both) in the high CgA group. Detailed analyses on gastric tissue samples confirmed a progression of enterochromaffin-like cell hyperplasia (P = 0.0192) accompanied by CgA elevation (P = 0.0316). CONCLUSIONS: The early detection and follow up of the later progression of enterochromaffin-like cell hyperplasia and autoimmune gastritis into gastric neuroendocrine tumors, which have ~100-fold greater incidence in type 1 diabetes patients, can be achieved by assessment of CgA levels. Therefore, the use of CgA could be considered as a novel auxiliary biomarker in the care of these type 1 diabetes complications.

Gastric cancer and gastrin: on the interaction of Helicobacter pylori gastritis and acid inhibitory induced hypergastrinemia.

Gastric cancer, a disease with a reduced frequency for decades, now appears to be on the rise again in young Americans. The epidemiology of gastric cancer differs between tumors in the cardia and those of the more distal parts of the stomach. The tumors are divided into the intestinal type showing glandular growth pattern and the diffuse type with a different pattern. The latter often expresses neuroendocrine and more specifically ECL-cell markers suggesting that they originate from the ECL cell, the target cell for the antral hormone, gastrin. Helicobacter pylori gastritis is accepted as the major cause of gastric cancer, but only after having induced oxyntic atrophy which reduces gastric acid secretion and thus induces hypoacidity leading to hypergastrinemia. Long-term hypergastrinemia is known to induce malignant neoplasia in the stomach of animals as well as man. Recently treatment with proton pump inhibitor after Helicobacter pylori eradication in patients with gastroesophageal reflux disease, has been reported to predispose to gastric cancer. Since profound acid inhibition is a well-known cause of gastric neoplasia, it is to be expected that Helicobacter pylori infection and profound acid inhibition has an additive or possibly potentiating effect on the development of gastric cancer.

The Enterochromaffin-like [ECL] Cell-Central in Gastric Physiology and Pathology.

BACKGROUND: Studies on the regulation of gastric and pancreatic secretion began more than 100 years ago. Secretin was the first hormone postulated to exist, initiating the field of endocrinology. Gastrin produced in the antral mucosa was the second postulated hormone, and together with histamine and acetylcholine, represent the three major gastric acid secretagogues known since 1920. For a long time, the mast cell was the only recognized histamine-producing cell in the oxyntic mucosa and, in the mid-1980s, the ECL cell was recognized as the cell producing histamine, taking part in the regulation of gastric acid secretion. METHODS: This review is based upon literature research and personal knowledge. RESULTS: The ECL cell carries the gastrin receptor, and gastrin regulates its function (histamine release) as well as proliferation. Long-term hypergastrinemia results in gastric neoplasia of variable malignancies, implying that gastric hypoacidity resulting in increased gastrin release will induce gastric neoplasia, including gastric cancer. CONCLUSIONS: The trophic effect of gastrin on the ECL cell has implications to the treatment with inhibitors of acid secretion.

Autoimmune gastritis: relationships with anemia and Helicobacter pylori status.

BACKGROUND: Autoimmune gastritis (AIG) is a gastric pathologic condition affecting the mucosa of the fundus and the body and eventually leading to hypo-achlorhydria. AIMS: We report our clinical and pathological experience with AIG. METHODS: Data from patients with a diagnosis of AIG seen in the period January 2002-December 2012 were retrieved. Only patients with complete sets of biopsies were analyzed. RESULTS: Data from 138 patients were available for analysis. Pernicious anemia was present in 25% of patients, iron deficiency anemia was found in 29.7% of patients, hypothyroidism in 23% of patients, type 1 diabetes in 7.9% of patients, and vitiligo in 2.8% of patients. Parietal cell antibodies were positive in 65% of patients, and no patient had serology positive for celiac disease. All gastric biopsies showed glandular atrophy associated with enterochromaffin-like (ECL)-cells hyperplasia, features limited to the mucosa of the fundus and body, and focal glandular intestinal metaplasia. Helicobacter pylori was negative in all cases. CONCLUSIONS: AIG was strongly associated with anemia; atrophy, intestinal metaplasia and ECL hyperplasia in the gastric fundus and body are hallmarks of this condition.

Follow-up of patients with ECL cell-derived tumours.

OBJECTIVES: To review the presentation, treatment and outcome of patients with type 1 gastric carcinoid tumours. MATERIAL AND METHODS: We retrospectively reviewed medical records and re-evaluated histopathological specimens of 26 patients with type 1 gastric carcinoids treated at a single tertiary referral centre from 1993 to 2013, with median time of follow-up 52.5 months (IQR 90.8). RESULTS: Seven patients (27%) had single tumours and 19 patients (73%) multiple tumours at the time of diagnosis. The median number of tumours and median diameter of largest tumour were 2.5 (IQR 3.2) and 6.0 mm (IQR 9.5) respectively. Median serum gastrin was 321.0 pmol/l (IQR 604.0) and median serum chromogranin A 7.7 nmol/l (IQR 5.3). Three patients had metastatic disease at the time of diagnosis and two developed metastases during follow-up. Patients with metastatic disease had larger primary tumours than the others (20.0 mm (IQR 28.5) vs. 5.0 mm (IQR 5.5), p = 0.04). There was a positive correlation between age and tumour size (r = 0.44, p = 0.03) and between serum chromogranin A and serum gastrin at diagnosis (r = 0.76, p = 0.001). Patients were either treated with surgery (n = 8 (31%)), a long-acting somatostatin analogue and/or gastrin receptor antagonist (n = 10 (39%)) for a period of time, or were observed without treatment (n = 8 (31%) with close endoscopic follow up. CONCLUSIONS: Although gastric carcinoids have an overall good prognosis, a significant proportion develops metastatic disease. As partial and total gastrectomy is associated with major side effects, treatment with long-acting a somatostatin analogue or gastrin antagonist should be considered.

PAI-1 deficiency increases the trophic effects of hypergastrinemia in the gastric corpus mucosa.

The gastric hormone gastrin plays a role in organizing the gastric mucosa. Gastrin also regulates the expression of genes that have important actions in extracellular matrix modelling, including plasminogen activator inhibitor (PAI)-1 which is part of the urokinase plasminogen activator (uPA) system. The uPA system (including PAI-1) is associated with cancer progression, fibrosis and thrombosis. Its biological role in the stomach and molecular mechanisms of action are not well understood. The aim of this study was to examine the effect of PAI-1 on the trophic changes observed in gastric corpus mucosa in hypergastrinemia using PAI-1 and/or HK-ATPase beta subunit knockout (KO) mice. HK-ATPase beta subunit KO mice were used as a model of hypergastrinemia. In 12 month old female mice, intragastric acidity and plasma gastrin were measured. The stomachs were examined for macroscopic and histological changes. In mice null for both PAI-1 and HK-ATPase beta (double KO), there was exaggerated hypergastrinemia, increased stomach weight and corpus mucosal thickness, and more pronounced trophic and architectural changes in the corpus compared with HK-ATPase beta KO mice. Genome-wide microarray expression data for the gastric corpus mucosa showed a distinct gene expression profile for the HK-ATPase beta KO mice; moreover, enrichment analysis revealed changes in expression of genes regulating intracellular processes including cytoskeleton remodelling, cell adhesion, signal transduction and epithelial-to-mesenchymal transition (EMT). Genes differentially expressed in the double KO compared with HK-ATPase beta KO mice included the transcription factor Barx2 and the chromatin remodeler gene Tet2, which may be involved in both normal gastric physiology and development of gastric cancer. Based on the present data, we suggest that PAI-1 plays a role in maintaining gastric mucosal organization in hypergastrinemia.

Does long-term profound inhibition of gastric acid secretion increase the risk of ECL cell-derived tumors in man?

OBJECTIVE: Since the description of ECL cell-derived tumors in rodents after long-term profound acid inhibition inducing hypergastrinemia, there has been concern that proton pump inhibitors (PPIs) could also do that in man. The recent description of a Spanish family with gastric ECL cell tumors at the age of about 30 years secondary to a defect in the proton pump due to mutation in the ATP4A gene clearly shows that hypergastrinemia alone also is sufficient to induce ECL cell neoplasia in man. The present review aims to evaluate the risk of gastric neoplasia secondary to gastric acid inhibition. METHODS: Literature (MEDLINE) was searched for the role of the ECL cell in gastric carcinogenesis in animals and man in general and particularly secondary to long-term inhibition of acid secretion. RESULTS: An important proportion of patients treated with PPI develops hypergastrinemia causing ECL cell hyperplasia and the first descriptions of ECL cell carcinoids secondary to PPI have been reported. The role of the ECL cell has hitherto been under estimated in gastric carcinogenesis in man where for instance the signet ring cell type of gastric carcinoma seems to originate from the ECL cell. CONCLUSIONS: The first two of three steps in rodent ECL cell carcinogenesis (hyperplasia, carcinoid, and carcinoma) secondary to PPI dosing, have been described for man. It is every reason to believe that the final step, gastric carcinoma, will develop also in man. Clinical decisions should be based not only on so-called evidence based medicine, but also on physiological knowledge and animal studies.

Systematic review: the effects of long-term proton pump inhibitor use on serum gastrin levels and gastric histology.

BACKGROUND: Proton pump inhibitors (PPIs) have a well-established safety profile. However, concerns have been raised about a potential relationship between PPI-induced hypergastrinaemia and the development of enterochromaffin-like (ECL) cell hyperplasia, neuroendocrine tumours and gastric cancer during long-term therapy. AIM: To review the effects of long-term PPI use on serum gastrin levels and gastric histopathology. METHODS: A systematic literature search was conducted in PubMed on 21 April 2015 to identify studies reporting the effects of long-term (defined as >3 years) PPI use on gastrin levels and gastric histopathology. RESULTS: A total of 16 studies (1920 patients) met the inclusion criteria. During long-term PPI therapy, mean gastrin levels rose to one to three times the upper limit of the normal range (~100 pg/mL), and an increased prevalence of ECL cell hyperplasia was observed (+7.8-52.0%). Helicobacter pylori-positive patients had a significantly increased risk of developing ECL linear/micronodular hyperplasia compared with H. pylori-negative patients [OR: 2.45 (95% CI: 1.47-4.10), P = 0.0006]; however, no evidence of neoplastic changes was found. The risk of corpus atrophy was markedly higher in H. pylori-positive patients than in H. pylori-negative patients [OR: 11.45 (95% CI: 6.25-20.99), P < 0.00001]. Not a single case of gastric adenocarcinoma was found. CONCLUSIONS: Long-term PPI therapy induced moderate hypergastrinaemia in most patients and an increased prevalence of ECL cell hyperplasia. H. pylori-positive patients receiving long-term PPI therapy were exposed to a higher risk of corpus atrophy than H. pylori-negative patients. No neuroendocrine tumours or gastric cancers were found.

Long-term proton pump inhibitor (PPI) use and the development of gastric pre-malignant lesions.

BACKGROUND: Proton pump inhibitors (PPIs) are the most effective drugs to reduce gastric acid secretion. PPIs are one of the most commonly prescribed classes of medications worldwide. Apart from short-term application, maintenance therapy with PPIs is recommended and increasingly used in certain diseases, such as Zollinger-Ellison syndrome and gastro-oesophageal reflux disease, especially for people with erosive oesophagitis or Barrett's oesophagus. Although PPIs are generally safe, their efficacy and safety of long-term use remains unclear. The question of whether the long-term use of PPIs could promote the development of gastric pre-malignant lesions has been widely investigated, but results are inconsistent. Limited insight on this problem leads to a dilemma in decision making for long-term PPI prescription. OBJECTIVES: To compare the development or progression of gastric pre-malignant lesions, such as atrophic gastritis, intestinal metaplasia, enterochromaffin-like (ECL) cell hyperplasia, and dysplasia, in people taking long-term (six months or greater) PPI maintenance therapy. SEARCH METHODS: We searched the following databases (from inception to 6 August 2013): the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and CINAHL. In addition, we searched the reference lists of included trials and contacted experts in the field. SELECTION CRITERIA: We searched for randomised controlled trials (RCTs) in adults (aged 18 years or greater) concerning the effects of long-term (six months or greater) PPI use on gastric mucosa changes, confirmed by endoscopy or biopsy sampling (or both). DATA COLLECTION AND ANALYSIS: Two review authors independently performed selection of eligible trials, assessment of trial quality, and data extraction. We calculated odds ratios (OR) for analysis of dichotomous data and mean differences for continuous data, with 95% confidence intervals (CI). MAIN RESULTS: We included seven trials (1789 participants). Four studies had high risk of bias and the risk of bias in the other three trials was unclear. In addition, it was difficult to assess possible reporting bias. We pooled 1070 participants from four RCTs to evaluate corporal atrophy development revealing an insignificantly increased OR of 1.50 (95% CI 0.59 to 3.80; P value = 0.39; low-quality evidence) for long-term PPI users relative to non-PPI users. In five eligible trials, corporal intestinal metaplasia was assessed among 1408 participants, also with uncertain results (OR 1.46; 95% CI 0.43 to 5.03; P value = 0.55; low-quality evidence). However, by pooling data of 1705 participants from six RCTs, our meta-analysis showed that participants with PPI maintenance treatment were more likely to experience either diffuse (simple) (OR 5.01; 95% CI 1.54 to 16.26; P value = 0.007; very-low-quality evidence) or linear/micronodular (focal) ECL hyperplasia (OR 3.98; 95% CI 1.31 to 12.16; P value = 0.02; low-quality evidence) than controls. No participant showed any dysplastic or neoplastic change in any included studies. AUTHORS' CONCLUSIONS: There is presently no clear evidence that the long-term use of PPIs can cause or accelerate the progression of corpus gastric atrophy or intestinal metaplasia, although results were imprecise. People with PPI maintenance treatment may have a higher possibility of experiencing either diffuse (simple) or linear/micronodular (focal) ECL cell hyperplasia. However, the clinical importance of this outcome is currently uncertain.

The gastric mucosa 25 years after proximal gastric vagotomy.

OBJECTIVE: Vagotomy causes inhibition of basal and post-prandial acid secretion in humans, but the knowledge about the trophic effect of the vagal nerves is limited. Vagotomy is known to induce hypergastrinemia and we aimed to study the long-term effects of proximal gastric vagotomy (PGV) on the oxyntic mucosa and the enterochromaffin-like (ECL) cell density in particular. MATERIAL AND METHODS: Eleven patients operated with PGV because of duodenal ulcer and age- and sex-matched controls were examined 26 to 29 years postoperatively by gastroscopy with biopsies from the antrum and oxyntic mucosa. Neuroendocrine cell volume densities were calculated after immunohistochemical labeling of gastrin, the general neuroendocrine cell marker chromogranin A (CgA) and the ECL cell marker vesicular monoamine transporter 2 (VMAT2). Gastritis was graded and Helicobacter pylori (H. pylori) status was determined by polymerase chain reaction of gastric biopsies. Fasting serum gastrin and CgA were measured. RESULTS: Serum gastrin was higher in the PGV group compared to controls (median 21.0 [interquartile range (IQR) = 22.0] pmol/L vs 13.0 [IQR = 4.0] pmol/L, p = 0.04). However, there was neither a significant difference in serum CgA or in CgA (neuroendocrine) nor VMAT2 (ECL cell) immunoreactive cell volume density in the oxyntic mucosa. There was significantly more inflammation and atrophy in H. pylori-positive patients, but PGV did not influence the grade of gastritis. CONCLUSION: Despite higher serum gastrin concentrations, patients operated with PGV did not have higher ECL cell mass or serum CgA. Vagotomy may prevent the development of ECL cell hyperplasia caused by a moderate hypergastrinemia.

Neuroendocrine pathology of the stomach: the Parma contribution.

The current knowledge on gastric neuroendocrine pathology essentially developed in the last four decades. The historical evolution of the concepts and of the relevant clinical implications is described from the perspective of a group actively participating in this research domain. The histamine-producing enterochromaffin-like (ECL) cells have been recognized as the leading cell type involved in the most significant alterations of gastric neuroendocrine cells. The trophic stimulus exerted by circulating gastrin has been demonstrated to have a crucial role on proliferative changes of ECL cells through a sequence of hyperplasia-dysplasia-neoplasia described by Solcia et al. (Digestion 41:185-200,1988). The development of ECL cell tumors in rats treated with toxicological doses of inhibitors of gastric acid secretion prompted appropriate anatomoclinical investigations proving the lack of tumor risk in humans when therapeutic dosages of the drugs are used. Moving from the comprehensive concept of gastric carcinoid, different types of neuroendocrine tumors have been identified in the stomach with substantial variations in prognosis and treatment options. In general, ECL cell tumors developed in hypergastrinemic conditions were found to behave better than those originating outside the setting of hormonal stimulation. Pathological features highly predictive of patient survival have been described. The genetic changes involved in tumor development and progression have revealed substantial overlapping with those of neuroendocrine tumors of other foregut derivatives (i.e., pancreas, duodenum, lung) delineating a family of neuroendocrine tumors genetically distinct from those of the distal parts of the digestive system.

Predictive value of gastrin levels for the diagnosis of gastric enterochromaffin-like cell hyperplasia in patients with Hashimoto's thyroiditis.

AIM: Gastrin and chromogranin A (CgA) levels have been tested for the diagnosis of enterochromaffin-like cell hyperplasia (ECLH) in patients with type 1 diabetes and autoimmune atrophic gastritis but not for patients with Hashimoto's thyroiditis (HT). The aim of the study was to develop receiver operating characteristic (ROC) curves for gastrin and CgA levels and other clinical and biochemical parameters, as means for pretest probability of gastric ECLH in patients with HT. METHODS: A total of 115 patients with HT were prospectively studied for a median period of 4 (2-7) years. Gastrin, CgA, vitamin B12, anti-parietal cell antibodies, free thyroxine, thyrotropin, and neuron-specific enolase levels were measured. Their predictive values were calculated according to the histological findings for ECLH diagnosis from esophagogastroduodenoscopy-obtained biopsies. RESULTS: Thirteen patients (11.3%) had ECLH. The areas under the curve for gastrin and CgA level were 0.898 (p < 0.001) and 0.853 (p < 0.001), respectively. The product sensitivity × specificity was 0.803 and 0.653 for gastrin and CgA levels >89.5 and >89.1 ng/ml, respectively. Two and 4 patients with ECLH had normal gastrin and CgA levels, respectively. The most specific combined parameters predicting ECLH were gastrin >89.5 ng/ml with concomitant low B12 levels (96.1% specificity). CONCLUSION: Gastrin levels have high diagnostic accuracy for ECLH identification in patients with HT, and are highly specific when combined with low B12 levels. However, they should be interpreted with caution, as some patients may harbor gastric ECLH even if gastrin levels are not increased, necessitating further follow-up.