Antral gastrin cell hyperfunction in children. A functional and immunocytochemical report

Development of a novel autoantibody assay for autoimmune gastritis in type 1 diabetic individuals

BACKGROUND

Autoimmune atrophic body gastritis (ABG) and pernicious anaemia are prototypical, organ-specific autoimmune diseases whose prevalence in the general population is 2.0 vs 2 and 0.15-1%, respectively. The incidence of disease increases with age and is frequently associated with other autoimmune disorders such as type 1 diabetes mellitus (T1DM). Early diagnosis of ABG/pernicious anaemia is essential for the prevention and/or treatment before manifestations of chronic disease become irreversible. Parietal cell autoantibody detection via enzyme-linked immunosorbent assay is currently the most widely used biomarker of disease with diagnosis confirmed by subsequent immunohistochemistry via biopsy.

METHODS

To improve the assay we designed a specific, molecularly defined radioimmunoprecipitation assay for early detection of ABG, targeting its major antigen, the gastric H+/K+ ATPase 4A subunit ATP4A.

RESULTS

The major antigenic domain in ATP4A was tested against a panel of sera from new onset patients with T1DM which tested positive for the gold standard T1DM autoantibodies (IAA, IA2A, GAD65A, and ZnT8A). Significant immunoreactivity to ATP4A was measured (25%) while 6% of first-degree relatives of subjects with T1DM who were sero-negative for T1DM autoantigens were positive for ATP4A autoantibodies. ATP4A antibody prevalence increased with age of onset of T1DM, which is atypical of other T1DM autoantibodies. Immunoreactivity to ATP4A, unlike that of T1DM antigens, demonstrates a significant gender bias in newly diagnosed individuals with T1DM.

CONCLUSION

Although the utility of the assay as a biomarker for T1DM is likely limited, it may serve as an improved indicator of ABG.

Pathology of gastrointestinal disorders

Nonneoplastic and neoplastic proliferative lesions of endocrine cells of the gastrointestinal tract are detailed. A multistep continuum from hyperplasia, dysplasia to neoplasia is identified for histamine-producing enterochromaffin-like (ECL) cells of the gastric corpus. Most gastric neuroendocrine tumors (NETs) are silent and composed by ECL cells, the second most frequent neuroendocrine neoplasms being the high-grade neuroendocrine carcinoma (NEC). In the duodenum, preneoplastic lesions are similarly described for gastrin (G) and somatostatin (D) cells. G-cell NETs are the most frequent neuroendocrine tumors of the duodenum, either functioning or nonfunctioning, followed by D-cell NETs and gangliocytic paraganglioma (GCP). No systematic definition of nonneoplastic lesions exists for endocrine cells of the ileum, appendix, and colon-rectum. The most frequent ileal NETs are serotonin-producing enterochromaffin (EC)-cell NETs (classic carcinoid), associating with functional syndrome only in presence of liver metastases. Neoplasms are usually larger in the colon as compared with the small lesions observed in the rectum. High-grade NECs are observed in the colon and rectum-sigmoid, often associate with nonendocrine neoplastic components, and fare an aggressive course with poor outcome and short survival.

[Pseudo Zollinger-Ellison syndrome in a patient with duodenal stenosis caused by tuberculosis]

We report the case of a 32-year-old Indian man with symptoms suggesting Zollinger-Ellison syndrome including abdominal pain, esaphagitis, duodenal stenosis that did not improve with antisecretory medication, elevated fasting gastrin serum levels that increased after intravenous secretin injections, elevated chromogranin A serum levels and tumoral aspect of pancreatic uncus on CT scan examination. A pancreaticoduodenectomy was performed. Histological examination of the resected specimen showed that there was no endocrine tumour of the pancreas or the duodenum, but identified marked lesions of follicular and caseous tuberculosis. The final diagnosis retained pseudo Zollinger-Ellison syndrome due to gastric outlet obstruction caused by duodenal stenosis of a tuberculosis origin.

Ultrastructural immunohistochemical localization of gastrin, somatostatin and serotonin in endocrine cells of human antral gastric mucosa

Five types of endocrine cells are found in the human antral gastric mucosa: gastrin (G) cells, somatostatin (D) cells, enterochromaffin (EC) cells and cells with an unknown secretory product (D1 cells and P cells). The content of secretory granules, gastrin, somatostatin and serotonin, was evaluated using electron microscopic immunohistochemistry and was compared with the granular content in G cells, D cells and EC cells as determined by routine electron microscopy. Semi-quantitative scoring of the granular content was performed on a scale 1-4 (empty-full). The content of gastrin (2.5 +/- 0.2) and somatostatin (3.3 +/- 0.2) in the granules was not different from the granular content in G cells (2.5 +/- 0.3; p > 0.05) and D cells (3.5 +/- 0.2; p > 0.05). Gastrin was also found in G cells in a nongranular form. The content of serotonin in granules (2.8 +/- 0.3) was smaller than the granular content in EC cells (3.7 +/- 0.2; p < 0.05). In intermediate-full and intermediate-empty granules, serotonin was localized in the periphery of granules whereas the granular content in EC cells was localized in an eccentric or central pattern. The granular content of D1 cells and P cells was 3.8 +/- 0.2, and 3.4 +/- 0.2, respectively. It is concluded that gastrin and somatostatin immunostaining in granules of G cells and D cells reflects the granular content in G cells and D cells, respectively, whereas serotonin immunostaining does not agree with the granular content of EC cells.

First endoscopic-histologic follow-up in patients with body-predominant atrophic gastritis: when should it be done?

BACKGROUND

Body-predominant atrophic gastritis is considered a risk factor for gastric cancer and carcinoid. Timing of follow-up for patients with this disorder has not been defined. This study was undertaken to determine the optimal time for the first endoscopic/histologic follow-up in patients with body-predominant atrophic gastritis.

METHODS

Forty-two patients with body-predominant atrophic gastritis were randomly assigned to 1 of 2 follow-up intervals: group A (n = 22) at 24 months and group B (n = 20) at 48 months. At baseline and follow-up patients underwent gastroscopy at which biopsies were obtained from the antrum and body for histopathology and evaluation for enterochromaffin-like cells.

RESULTS

In group A patients, 2 antral hyperplastic polyps (9.1%) were present at baseline and 4 antral hyperplastic polyps (18.2%) were found at follow-up. In group B patients, baseline gastroscopy revealed 2 antral hyperplastic polyps (10%) and follow-up 2 antral hyperplastic polyps (10%) and 1 carcinoid tumor (5%) in the body. Atrophy and intestinal metaplasia scores in gastric body and antral mucosa in both groups did not change significantly between baseline and follow-up, except an increase in antral mucosa atrophy in group B patients (p = 0.02) was revealed.

CONCLUSIONS

The results of this study indicate that performing the first follow-up in patients with body-predominant atrophic gastritis need not be earlier than at 4 years after diagnosis. This interval is satisfactory for detection of potential neoplastic lesions.

Role of Helicobacter pylori infection in pernicious anaemia

BACKGROUND

Pernicious anaemia is associated with atrophic body gastritis and considered an autoimmune disease. Whether Helicobacter pylori is involved in the induction of pernicious anaemia is uncertain.

AIMS

To investigate the prevalence of Helicobacter pylori infection in pernicious anaemia patients and to ascertain whether the Helicobacter pylori-positive patients had distinctive clinical and gastric morphofunctional characteristics.

PATIENTS AND METHODS

A series of 81 consecutive pernicious anaemia patients underwent serological, functional and endoscopic/histological investigations.

RESULTS

A total of 49 (60.5%) patients were Helicobacter pylori-positive (males 61.2% vs females 38.8%). No difference was observed in clinical and morphofunctional characteristics between Helicobacter pylori-positive and negative patients, whereas distinctive functional/histological features between histologically Helicobacter pylori-positive (n=8) and serologically Helicobacter pylori-positive (n=41) cases were detected. In the histologically Helicobacter pylori-positive group, Pepsinogen I was higher [13 (058) vs 5 (0-26) ng/ml; p=0.0025)] and positivity for anti-parietal cell antibodies was lower [42.9% vs 76.9, p=0.0867]. Antral histological variables of the gastritis score were significantly higher in the histologically Helicobacter pylori-positive than in the serologically Helicobacter pylori-positive patients, but this latter group had a higher score of body atrophy (2.63+/-0.12 vs 1.71+/-0.29; p=0.0051). Body inflammation was also significantly higher in the histologically Helicobacter pylori-positive group (chronic inflammation: 1.43+/-0.2 vs 1.05+/-0.06; p=0.0271; inflammation acitivity: 0. 57+/-0.3 vs 0.15+/-0.06, p=0.0220). Antral mucosa was normal in 24/41 (58.5%) of the serologically Helicobacter pylori-positive patients, but only in 1/8 (12.5%) of the histologically Helicobacter pylori-positive patients (p=0.0232).

CONCLUSIONS

Almost two thirds of pernicious anaemia patients have evidence of Helicobacter pylori, but only those with an active Helicobacter pylori infection have distinctive functional and histological features. These findings support the hypothesis that Helicobacter pylori infection could play a triggering role in a subgroup of pernicious anaemia patients.

ECL cell tumor and poorly differentiated endocrine carcinoma of the stomach: prognostic evaluation by pathological analysis

BACKGROUND & AIMS

Gastric endocrine tumors show a wide spectrum of clinical behavior, and prognostic assessement of individual tumors is difficult. The aims of this work were to identify predictors of tumor malignancy and patient outcome and to provide a rationale for treatment guidelines.

METHODS

Gastric endocrine tumors (86 enterochromaffin-like cell carcinoids and 16 poorly differentiated carcinomas) were investigated for 15 clinicopathologic variables and for expression of Ki67, P53, and BCL-2 proteins. Data were analyzed by univariate and multivariate statistics for evidence of tumor malignancy and patient survival.

RESULTS

Histological grades 2 and 3, size >/=3 cm, 9 or more mitoses, or >/=300 Ki67-positive cells per 10 high-power fields identified 26 of 33 (79%) malignant (metastatic or deeply invasive) tumors, and size <1 cm and/or growth restricted to the mucosa characterized 46 of 69 (67%) tumors with benign behavior during a median follow-up of 39 months. Malignancy-predictive models were developed using angioinvasion, size, clinicopathologic type, mitotic index, and Ki67 index. The same variables, in addition to deep gastric wall invasion and histological grade, predicted patient outcome.

CONCLUSIONS

Criteria for the assessment of malignancy risk and patient outcome were developed for the different tumors, providing a basis for treatment guidelines.

High prevalence of atrophic body gastritis in patients with unexplained microcytic and macrocytic anemia: a prospective screening study

OBJECTIVE

Atrophic body gastritis (ABG) is characterized by atrophy of the gastric body mucosa, hypergastrinemia, and hypo/achlorhydria. Its association with pernicious anemia is well recognized. Gastric hypo/achlorhydria is known to affect iron absorption but ABG is rarely considered as a possible cause of iron deficiency (microcytic) anemia. The aims of this study were to validate a screening methodology for the detection of ABG in a consecutive series of patients with microcytic and macrocytic anemia and to investigate the clinical and gastric morphofunctional characteristics of the two hematological presentations of ABG.

METHODS

A two-part prospective study was carried out. Part A aimed to validate the screening methodology to detect the presence of ABG in patients with macrocytic and microcytic anemia who have no specific GI symptoms, by measuring their gastrin levels and verified by performing gastroscopy with biopsy. Part B aimed to detect the presence of ABG in a larger sample of anemic patients by our validated method and, by pooling the data of ABG patients, to determine the clinical, gastric histological, and functional characteristics pertaining to the macrocytic and microcytic presentations of ABG.

RESULTS

In part A, ABG was detected in 37.5% of patients with macrocytic and in 19.5% of those with microcytic anemia. Pooling the data of the ABG patients from part A and part B, microcytic ABG patients were on average 20 yr younger than those with macrocytic anemia. The majority of microcytic ABG patients were female, most of whom were premenopausal. H. pylori infection was widely represented in the microcytic ABG group (61.1%). They also had a lesser grade of body mucosal atrophy and lower hypergastrinemia levels, suggesting a less severe oxyntic damage of shorter duration.

CONCLUSIONS

Macrocytic anemia is not the only hematological presentation of ABG. Physicians evaluating patients with unexplained iron deficiency anemia should consider ABG as a possible cause by determining fasting gastrin levels and performing gastroscopy with biopsies of the body mucosa.

Hypergastrinemia and enterochromaffin-like cell hyperplasia

The enterochromaffin-like (ECL) cells, the most frequent endocrine cells of the oxyntic mucosa of the stomach, are under the trophic stimulus of gastrin. These cells undergo a hyperplastic increase in variety of hypergastrinemic diseases. The most widely accepted nomenclature for the description of hyperplastic proliferation has been retrospectively arranged in a sequence presumed to reflect a temporal evolution of the proliferative process. A comparative, prospective study aimed to verify, in human hypergastrinemic diseases such as atrophic body gastritis (ABG), Zollinger-Ellison syndrome (ZES) and antral gastrin cell hyperfunction (AGCH), the effect of exposure of ECL cells to different pattern of gastrin hypersecretion, is lacking. To this purpose, we studied a series of consecutive patients with ABG, ZES and AGCH at the time of first diagnosis.

MATERIAL AND METHODS

The patients included in this study (124 ABG, 18 ZES and 10 AGCH) were selected on the basis of two previously performed screening studies aimed to diagnose these diseases. All patients at the time of diagnosis underwent gastroscopy, with multiple biopsies of the gastric body mucosa for the evaluation of qualitative pattern of ECL cells hyperplasia, and basal fasting gastrin determination. A sample of hypergastrinemic patients from each group was further investigated by meal-stimulation of gastrin secretion and quantitative morphometry for CgA positive gastric body endocrine cells.

RESULTS

AGCH patients showed only the normal or simple hyperplasia pattern. In the ZES group, simple and linear grades accounted for 38.4 percent and 46.1 percent, respectively. MEN-I patients showed only these two patterns. The majority of ABG patients showed the presence of micronodular pattern (59.7 percent). A correlation analysis between fasting gastrin levels and grade of hyperplasia (r = 0.5580, p < 0.0001), indicates that the greater the gastrin levels, the higher is the degree of severity of ECL hyperplasia pattern. In conclusion, our data support the role of gastrin as the selective contributor to the progression of ECL cell hyperplasia in humans.

Atrophic body gastritis: distinct features associated with Helicobacter pylori infection

BACKGROUND

Usually, atrophic body gastritis has been considered an autoimmune disease characterized by the presence of parietal cell antibodies. Previous investigations into the role of Helicobacter pylori infection have obtained conflicting results. The aim of this study was to investigate the prevalence and role of H. pylori in a prospectively investigated population of patients with corpus-predominant atrophic gastritis.

PATIENTS AND METHODS

A consecutive series of 67 newly diagnosed cases of atrophic body gastritis was derived from a screening of 326 patients with unexplained anemia or dyspepsia. Criteria for diagnosis were fasting hypergastrinemia, pentagastrin-resistant achlorhydria, and histological confirmation of body atrophy. In all 67 patients, H. pylori infection was evaluated independently by histological assay and urease test. The gastritis status of both the fundic and antral mucosa were graded according to the Sydney system. Parietal cell and intrinsic factor antibodies also were determined.

RESULTS

Active H. pylori infection was present in 26.8% of our patients and allowed us to identify a patient's subpopulation with a significantly smaller degree of body mucosa damage as shown by functional parameters (gastrin, gastric acid secretion, pepsinogen I) and histological assessment. In this subpopulation, a higher prevalence of gastric cancer familial history was found. Presence of parietal cell antibodies showed a similar prevalence in H. pylori-positive and H. pylori-negative patients (61.1% vs. 69.4%) and was not associated with significant functional and histological differences. Cure of infection determined an evident improvement of corporal atrophy as well as a reduction of hypergastrinemia.

CONCLUSION

Active H. pylori infection, a potential cause of oxyntic gland atrophy, is found in one-fourth of patients with newly diagnosed atrophic body gastritis.

Reversal of long-standing iron deficiency anaemia after eradication of Helicobacter pylori infection

Helicobacter pylori has been proposed as a major determinant in multiple gastric disorders. We describe the case of a young adult with a long-standing medical history of sideropenic anaemia and of oral iron consumption dependence with a chronic superficial H. pylori-positive gastritis. All other causes of sideropenic anaemia were carefully excluded. Histology showed a peculiar pattern of non-active H. pylori-positive gastritis. The bacterium was a non-VacA-producing strain. The first attempt at eradication caused a reduction in bacterial load and led to a partial normalization of haematologic variables without improving the ferritin level. A successful second course of eradication therapy completely reversed the anaemia and restored the iron deposit, which persisted at the 29-month follow-up. H. pylori infection can be involved in unexplained cases of iron deficiency anaemia in adults, and its cure can normalize the haematologic picture.

Helicobacter pylori, hypergastrinaemia, and recurrent abdominal pain in children

The association between Helicobacter pylori and recurrent abdominal pain (RAP) is controversial. In this cross-sectional study, the authors aim to determine whether hypergastrinaemia causes RAP in children with H pylori gastritis. In 439 children age 4 to 13 years (mean 7.3 years) attending for nongastrointestinal day-case surgery, anti-Helicobacter immunoglobulin G (IgG) was identified in serum by an enzyme-linked immunosorbent assay (ELISA) method validated in children and fasting plasma gastrin was measured. A history of RAP was sought. One hundred twenty-seven children (29%) tested seropositive for H pylori. Fifty-one seronegative children (16.3%) and 22 seropositive children (17.3%) gave a history of RAP. The mean fasting gastrin in seronegative children was 52 ng/L compared with 117 ng/L in seropositive children (P < .001). The mean fasting gastrin in seropositive children with RAP (124 ng/L) was not significantly different from that of seropositive children without RAP (115 ng/L). The high prevalence of H pylori seropositivity in this study is at variance with other reported paediatric data from the developed world. No association between childhood H pylori gastritis, hypergastrinaemia, and RAP was found. In children with H pylori gastritis, the increase in circulating gastrin (mean 140% increase) is greater than that seen in adults (50% increase).

Zollinger-Ellison syndrome and antral G-cell hyperfunction in patients with resistant duodenal ulcer disease

We measured basal and pentagastrin-stimulated acid secretion, as well as basal and meal-stimulated plasma gastrin concentration to determine, in 67 patients affected by resistant duodenal ulcer, whether their condition could be related to gastric acid secretion and/or gastrin-related syndromes. We then compared them to 46 duodenal ulcer control patients. The outpatients were investigated consecutively. The resistant duodenal ulcer patients differed from the controls only in their higher complication rates (bleeding or perforation, P < 0.05). We identified five patients in the resistant duodenal ulcer group with Zollinger-Ellison syndrome and 12 with antral G cell hyperfunction, whereas in the control group only one patient was affected by antral G cell hyperfunction. IgG anti-Helicobacter pylori antibodies were positive for the presence of infection in 7 of the hypergastrinaemic patients. When Zollinger-Ellison syndrome or antral G cell hyperfunction were excluded, no differences could be found in gastric acid secretion, or basal and meal-stimulated plasma gastrin levels, between the resistant and control duodenal ulcer patients, except for basal acid hypersecretion (resistant duodenal ulcer 16% vs duodenal ulcer 2% P = 0.0144). In the presence of duodenal ulcer disease resistant to H2-blockers, it is mandatory to measure basal plasma gastrin concentration since it was possible to diagnose the gastrin-related syndromes, Zollinger-Ellison syndrome and antral G cell hyperfunction, in 26% of this group of patients.

Morphometry of gastric endocrine cells in hypergastrinemic patients treated with the somatostatin analogue octreotide

The aim of the study was to evaluate whether treatment with 200 micrograms/d of the somatostatin analogue octreotide (SMS 201-995) for three months can influence the trophic action exerted by hypergastrinemia on endocrine cells of the oxyntic mucosa, a condition potentially leading to hyperplasia and carcinoid tumors. Endocrine cells were morphometrically investigated in Grimelius silver stained sections of endoscopic biopsies of oxyntic mucosa collected from 13 hypergastrinemic patients with Zollinger-Ellison syndrome (ZES) (n = 5), antral G cell hyperfunction (AGCH) (n = 4) and atrophic gastritis type A (AG-A) (n = 4) before and after 3 months treatment and 3 months after drug discontinuance. The treatment induced a reduction of the volume density (P < 0.015), profile cross sectional area (P < 0.05) and number of cell profiles per unit area (P < 0.015) of argyrophil cells. A rebound of all these parameters was observed 3 months after drug withdrawal with values usually exceeding those at the entry, except in cases of AG-A. The patients' plasma gastrin concentrations presented similar variations showing a significant relation with all morphometric parameters of argyrophil cells. Also, the cell content in alpha subunit of human chorionic gonadotropin was related to the plasma gastrin levels, a finding confirming the close gastrin dependence of the expression of this protein by oxyntic endocrine cells. No significant changes were observed in mucosal somatostatin D cells. These results indicate that variations in circulating gastrin levels are the most likely factor responsible for the hypotrophic effect of octreotide on oxyntic argyrophil cells (mostly corresponding to the ECL cells) of hypergastrinemic patients.