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Background Atrophic gastritis (AG) and use of proton pump inhibitors (PPIs) result in gastric acid suppression that can impair the absorption of vitamin B-12 from foods. The crystalline vitamin B-12 form, found in fortified foods, does not require gastric acid for its absorption and could thus be beneficial for older adults with hypochlorhydria, but evidence is lacking. Objectives To investigate associations of AG and PPI use with vitamin B-12 status, and the potential protective role of fortified foods, in older adults. Methods Eligible participants (n = 3299) not using vitamin B-12 supplements were drawn from the Trinity-Ulster and Department of Agriculture cohort, a study of noninstitutionalized adults aged ≥60 y and recruited in 2008–2012. Vitamin B-12 status was measured using 4 biomarkers, and vitamin B-12 deficiency was defined as a combined indicator value

Objective Calcium is an essential mineral involved in the functioning of nearly every human cell. Calcium levels are regulated by dietary absorption, vitamin D status, and parathyroid hormone (PTH). This report describes a patient in whom childhood bowel resection and partial gastrectomy resulted in malabsorptive hypocalcemia in adulthood. Case Report A 21-year-old man presented with syncope and a fall resulting in a right femoral neck fracture. His medical history included small bowel obstructions at age 9 requiring bowel resection, and at age 12 with gastric perforation and partial gastrectomy. Laboratory values showed calcium level of 4.9 mg/dL (8.9-10.3 mg/dL). PTH level was 273 pg/mL (12.0-88.0 pg/mL), 25-hydroxy-vitamin D was 28 ng/dL (30-100 ng/mL), and 1,25-dihydroxy-vitamin D was 54 pg/dL (18-72 pg/mL). Furthermore, magnesium and phosphorus levels were 2.1 mg/dL (1.5-2.6 mg/dL) and 4.4 mg/dL (2.4-4.7 mg/dL), respectively. Calcium levels improved to 9.5 mg/dL on 10% calcium gluconate drip but could not be maintained above 7 mg/dL on oral calcium carbonate supplementation, despite doses as high as 3750 mg three times daily with calcitriol 0.75 mcg twice daily. After switching from calcium carbonate to calcium citrate 3500 mg three times daily, the calcium level improved and was maintained between 8.3 and 9.0 mg/dL. Discussion High calcium needs, other nutrient deficiencies, and response to calcium citrate versus calcium carbonate suggest malabsorption from achlorhydria and small bowel resection. Conclusion This case emphasizes the gastrointestinal physiology in calcium homeostasis and highlights the recognition of hypocalcemia as a complication of gastric and bowel resection.

Vitamin B12 is an essential nutrient which plays an important role in neurological function, hematopoiesis, and DNA synthesis. Low levels usually stem from either poor intake or a malabsorptive process. Presently, the most common cause of vitamin B12 deficiency is food-bound cobalamin malabsorption, which occurs when there is impaired release of vitamin B12 from ingested food due to an outstanding factor preventing the release of the nutrient from its transport protein. Such causes include achlorhydria, gastritis, gastrectomy, or the use of PPIs or antacids. A rarer cause is autoimmune chronic atrophic gastritis, resulting in pernicious anemia. In this disease process, there is destruction of parietal cells and thus a reduction in intrinsic factor, which is essential to the absorption of vitamin B12. Deficiency will result in a variety of abnormalities including but not limited to pancytopenia, paresthesias, and neuropsychiatric symptoms. A rare manifestation of vitamin B12 deficiency is hemolytic anemia, which occurs due to intramedullary and extramedullary dysfunction. This case describes a 46-year-old male with no past medical history who presented with chest pain, fatigue, and progressive weakness, found to have hemolytic anemia, ultimately attributed to vitamin B12 deficiency. Antiparietal cell antibodies and intrinsic factor antibodies (IFA) were both negative. Still, the patient underwent an endoscopy with biopsies of the stomach; pathology was consistent with chronic metaplastic atrophic gastritis. The patient improved with intramuscular vitamin B12 supplementation. This case highlights both a rare cause and presentation of vitamin B12 deficiency. Patients with autoimmune chronic atrophic gastritis should have antiparietal cell or intrinsic factor antibodies. Still, seronegative patients have been reported, like this patient. Additionally, hemolytic anemia secondary to vitamin B12 deficiency is uncommon. The presentation will usually mirror that of a thrombotic microangiopathy (TMA), including hemolytic anemia with schistocytes on peripheral blood smear and thrombocytopenia, as it did in this patient. This clinical entity is described as pseudothrombotic microangiopathy and is crucial to identify in order to prevent the initiation of invasive treatment strategies such as plasmapheresis.

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.

Caustic ingestion can lead to structural changes in the upper gastrointestinal tract. However, there are limited data on the effect of caustic ingestion on gastric secretion. This study was planned to determine the changes in gastric acid output in patients with caustic ingestion. It was a prospective study done at a tertiary care center in northern India. Twenty consecutive patients in chronic phase of caustic ingestion were evaluated for the study. The gastric secretory function was estimated in the basal state and following pentagastrin stimulation. These results were compared with normal values for our laboratory. The mean age of the included patients (n = 20) was 27.35 ± 2.96 years and 14 patients were male. Sixteen (80%) patients had a history of acid ingestion. Patients with caustic ingestion had significantly lower mean gastric acid secretion (0.8 ± 0.4 mEq/h vs. 4 ± 0.4 mEq/h; p

Retrospective chart reviews have reported hypophosphatemia associated with elemental formula use in infants and children with systemic disease involving multiple diagnoses. The present study aims to evaluate the bioavailability of phosphorus from 2 commercial elemental formulas and to test our hypothesis of bioequivalence of the 2 products in healthy volunteers receiving gastric acid-suppressive medication. A single-center, double-blind, randomized, cross-over study was conducted in healthy volunteers with esomeprazole-induced hypochlorhydria. After a standardized low phosphorus meal followed by overnight fasting, subjects consumed 1 gram of phosphorus in a single oral dose of 1217 kcal of Product A (Neocate) or Product B (Elecare). The alternate product was given following a 1-week washout period. Blood and urine were collected at baseline and different time-points for up to 6 hours after product consumption. Area-under-the-curve (AUC) and peak values (C-peak) for serum phosphate and calcium and urinary creatinine-corrected phosphate and calcium were assessed for bioequivalence of Products A and B. Results show that the geometric mean ra tio (GMR) and 90% CI for serum phosphate were 1.041 (0.998-1.086) and 1.020 (0.963-1.080) for AUC(0-360) and C-peak, respectively, meeting the predetermined criteria for bioequivalence. Urinary creatinine-corrected phosphate followed a similar pattern after intake of Product A and B, but did not reach bioequivalence criteria (GMR: AUC(70-370) = 1.105 (0.918-1.330); C-peak = 1.182 (1.040-1.343)). Serum calcium concentrations (GMR: AUC(0-360) = 1.002 (0.9961.009); C-peak = 0.991 (0.983-0.999)) and urinary creatinine-corrected calcium excretion (GMR: AUC(70-370) = 1.117 (1.023-1.219); C-peak = 1.157 (1.073-1.247)) demonstrated bioequivalence of the products. In conclusion, both elemental infant formulas showed equivalent serum phosphorus and calcium bioavailability in healthy volunteers even if combined with treatment with acid-suppressive medication. (c) 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/ )

Small intestinal bacterial overgrowth (SIBO) is a common gastrointestinal (GI) problem, but its diagnosis is often missed in the clinical setting. Because its diagnosis mostly requires invasive testing, often its true prevalence is unknown. Commonly presenting complaints include abdominal distension, diarrhea, and malabsorption. Multiple predisposing factors have been recognized in peer-reviewed literature, including achlorhydria, motility disorders, anatomical abnormalities of the gastrointestinal tract, and immunodeficiency disorders, including cancer. Multiple culture-dependent and independent methods are used to confirm diagnosis. Symptomatic relief can be achieved through multiple antibiotics regimens, but correction of underlying etiology, if possible, is necessary for long-lasting cure. Increased awareness and clinical vigilance can transform the landscape of SIBO via better management of patients with GI and related disorders.

ObjectiveWe aimed to study the prevalence of achlorhydria (AC) in a large Asian population.DesignMedical records of patients who underwent oesophagogastroduodenoscopy (OGD) with Congo red staining method at the Vichaiyut Hospital from January 2010 to December 2019 were retrospectively reviewed.ResultsA total of 3597 patients was recruited; 223 were excluded due to concurrent use of proton pump inhibitors. Eighteen from 3374 patients (0.53%) had AC. Seven patients were presented with permanent AC (5F, 2M) (median age=69 years; range 58–92). Among 11 patients with temporary AC (5M, 6F: mean age 73.4 years; SD 13.2 years), all had gastrointestinal Helicobacter pylori bacterial infection and were over 45 years old. After successful treatment for H. pylori, AC was absent among patients with temporary AC. If counting only patients over 45 years of age, the prevalence of AC was 0.68% (18/2614). No adverse events arising from Congo red occurred.ConclusionAC is relatively rare. Permanent and temporary AC were found only when they were over 55 and 45 years old, respectively. Staining Congo red on gastric mucosa can be safely and routinely incorporated into the OGD procedure for early detection of AC. We recommended a low-cost screening test such as serum vitamin B levels for screening only in patients aged 50 and over.

The article defines chronic gastritis as a polyetiological and polypathogenetic stomach disease with a chronic, slowly progressing course, which is based on a specific inflammatory process with lymphoplasmocytic infiltration of its mucosa and neutrophilic component indicating its activity, and with development of disregenerative, dystrophic changes, leading to its secretory insufficiency, manifested hypo- and achlorhydria and gastric achilia. The history of studying chronic gastritis from the beginning of the 19th century till present days is briefly described. It is proposed to distinguish between causal (Helicobacter pylori, etc.) and predisposing (alcohol, smoking, coarse food, etc.) factors in the development of chronic gastritis. The analysis of various classifications of gastritis is carried out: based on etiology, pathogenesis, functional features, clinic, endoscopic and histological characteristics. The Sydney, Houston classifications, the OLGA system are described. Particular attention is paid to diagnosis, biopsy technique of the gastric mucosa, ratio of diagnoses of chronic gastritis and functional dyspepsia, as well as the role of gastric microflora in development of gastritis. It is revealed that gastric microflora in chronic gastritis is represented by numerous types of bacteria (more often in the form of bacterial associations), moreover, Helicobacter pylori is not the dominant microorganism colonizing the stomach, and the mucosal microflora found in the stomach has adhesiveness, invasiveness and pathogenic properties, including its urease activity.

Proton pump inhibitors (PPIs) are common medications within the practice of gastroenterology. These drugs, which act through the irreversible inhibition of the hydrogen/potassium pump (H+/K+-ATPase pump) in the gastric parietal cells, are used in the treatment of several acid-related disorders. PPIs are generally well tolerated but, through the long-term reduction of gastric acid secretion, can increase the risk of an imbalance in gut microbiota composition (i.e., dysbiosis). The gut microbiota is a complex ecosystem in which microbes coexist and interact with the human host. Indeed, the resident gut bacteria are needed for multiple vital functions, such as nutrient and drug metabolism, the production of energy, defense against pathogens, the modulation of the immune system and support of the integrity of the gut mucosal barrier. The bacteria are collected in communities that vary in density and composition within each segment of the gastrointestinal (GI) tract. Therefore, every change in the gut ecosystem has been connected to an increased susceptibility or exacerbation of various GI disorders. The aim of this review is to summarize the recently available data on PPI-related microbiota alterations in each segment of the GI tract and to analyze the possible involvement of PPIs in the pathogenesis of several specific GI diseases.

Introduction: VIPoma is a neuroendocrine tumor that secrets vasoactive intestinal peptide and produces a well-defined clinical syndrome characterized by watery diarrhea, hypokalemia, hypochlorhydria and metabolic acidosis. The aim of this study to investigate clinical studies about diagnostic and therapeutic modalities of vipoma patients. In this retrospective study, all patients of vipoma were investigated. Clinical features, laboratory data at initial presentation, management and outcomes were collected. Subjects and Methods: The paper has written based on searching PubMed and Google Scholar to identify potentially relevant articles or abstracts. Categorical variables as percentage and continuous variables were reported as mean ± standard deviation (SD). Results: All the patients presented with watery diarrhea (30/30, 100%) and dehydration was reported in 33.3% of them. Prevalence of laboratory findings in these patients were assessed for hypokalaemia (25/30, 83.3%), metabolic acidosis (9/30, 33.6%), hypochloremia and achlorhydria (2/30, 6.6%). Elevated VIP levels have been seen in 73.3% patients with mean values of 882.85 ± 1134.87 pg/ml. Prevalence of diagnostic methods included CT scan in 19 patients (19/30, 63.3%), ultrasonography (15/50, 50%), and somatostatin receptor scintigraphy (8/30, 26.6%). Medical treatments included somatostatin and analogues in 18 patients (18/30, 60%). Surgery included less percentage of treatment in these patients. Conclusion: CT scan can be used as a reliable modality for diagnosis of vipoma and somatostatin analogues can be used as the most effective treatment in vipoma patients. Surveillance of these patients needs to close monitoring of patients via history, physical examination, laboratory and imaging.

Vasoactive intestinal peptide-producing tumors (VIPoma) usually originate in the pancreas and are characterized by diarrhea, hypokalemia, and achlorhydria (WDHA syndrome). In adults, nonpancreatic VIPoma is very rare. Herein, we report an unusual case of VIP-producing pheochromocytoma marked by persistent shock, flushing, and watery diarrhea and high sensitivity to octreotide. A 53-year-old woman was hospitalized for sudden-onset hypertension with convulsions, which then rapidly evolved to persistent shock, flushing, and watery diarrhea. Abdominal computed tomography indicated a left adrenal mass, accompanied by bleeding; and marked elevations of both plasma catecholamine and VIP concentrations were documented via laboratory testing. Surprisingly, all clinical symptoms responded swiftly to octreotide treatment. Once surgically treated, hormonal levels normalized in this patient, and the clinical symptoms dissipated. Postoperative pathological and immunohistopathological studies confirmed a VIP-secreting pheochromocytoma with strong, diffuse positivity for somatostatin receptor type 2. During a 6-mo follow-up period, she seemed in good health and was symptom-free.

Background Chronic autoimmune atrophic gastritis (CAAG) is an autoimmune disease characterized by hypo/achlorhydria. A role of CAAG in the pathogenesis of nutritional deficiencies has been reported, therefore we hypothesized a possible association between CAAG and 25-OH-Vitamin D [25(OH)D] deficiency. Aim of the present study is to evaluate the prevalence of 25(OH)D deficiency in CAAG patients. Methods: 87 CAAG patients (71 females; mean age 63.5 ± 12.8 years) followed at our Centre from January 2012 to July 2015 were consecutively evaluated. 25(OH)D, vitamin B12, parathormone, and calcium were measured in all the CAAG patients. The results were compared with a control group of 1232 healthy subjects. Results In the CAAG group the mean 25(OH)D levels were significantly lower than in the control group (18.8 vs. 27.0 ng/ml, p

BackgroundPheochromocytoma (PHEO) clinical manifestations generally mirror excessive catecholamines secretion; rarely the clinical picture may reflect secretion of other hormones. Watery diarrhea, hypokalemia and achlorhydria (WDHA) is a rare syndrome related to excessive secretion of vasoactive intestinal peptide (VIP).Clinical CaseA 73-year-old hypotensive man affected by adrenal PHEO presented with weight loss and watery diarrhea associated with hypokalemia, hyperchloremic metabolic acidosis (anion gap 15 mmol/l) and a negative urinary anion gap. Abdominal computed tomography scan showed a right adrenal PHEO, 8.1 cm in maximum diameter, with tracer uptake on 68GaDOTA-octreotate positron emission tomography. Metastasis in lumbar region and lung were present. Both chromogranin A and VIP levels were high (more than10 times the normal value) with slightly elevated urine normetanephrine and metanephrine excretion. Right adrenalectomy was performed and a somatostatin analogue therapy with lanreotide started. Immunostaining showed chromogranin A and VIP co-expression, with weak somatostatin-receptor-2A positivity. In two months, patient clinical conditions deteriorated with severe WDHA and multiple liver and lung metastasis. Metabolic acidosis and hypokalemia worsened, leading to hemodynamic shock and exitus.ConclusionsA rare case of WDHA syndrome caused by malignant VIP-secreting PHEO was diagnosed. High levels of circulating VIP were responsible of the rapidly evolving clinical picture with massive dehydration and weight loss along with severe hyperchloremic metabolic acidosis and hypokalemia due to the profuse untreatable diarrhea. The rescue treatment with lanreotide was unsuccessful because of the paucity of somatostatin-receptor-2A on VIP-secreting PHEO chromaffin cells.

Background Hypochlorhydria (gastric pH >4) increases susceptibility to diarrhoea, iron deficiency, and gastric cancer. We sought to clarify the prevalence of this condition and its predisposing factors in Zambia by pooling data from previous studies conducted in hospital and community settings. Methods Gastric pH was measured in participants from five separate studies by collecting gastric aspirate from fasted adults and children under 3 years of age undergoing gastroscopy. Gastric pH was correlated with serological testing for Human Immunodeficiency Virus (HIV) and Helicobacter pylori (H. pylori) infections. Results We studied 597 individuals (487 adults and 110 children). Hypochlorhydria was present in 53% of adults and 31% of children. HIV infection was detected in 41% of adults and 11% of children. H. pylori serology was available for 366 individuals: 93% of adults and 6% of children were seropositive. In univariate analysis, hypochlorhydria was significantly associated with HIV seropositivity (OR 1.7; 95% CI 1.2–2.4; p = 0.004) and H. pylori antibody seropositivity (OR 4.9; 95% CI 2.8–8.6; pH. pylori was associated with hypochlorhydria (OR 4.0; 95% CI 2.2–7.2; p Conclusions Hypochlorhydria is common in our population, with H. pylori being the dominant factor. Only young HIV seronegative individuals had a low prevalence of hypochlorhydria. This may have implications for the risk of other health conditions including gastric cancer.

In corpus atrophic gastritis (CAG), hypochlorhydria makes plausible the overgrowth of intragastric bacteria, whose role in gastric carcinogenesis is under debate.To characterize the antrum/corpus composition of the gastric bacterial microbiota in CAG patients compared to controls without CAG.A cross-sectional monocentric study on consecutive patients with known histological diagnosis of CAG undergoing gastroscopy for gastric cancer surveillance and patients without CAG undergoing gastroscopy for dyspepsia or anemia (108 biopsies from 55 patients, median age 61.5). Genomic DNA from one antral and one corpus biopsy from each case (n = 23) and control (n = 32) was extracted. Gastric microbiota was assessed by sequencing hypervariable regions of the 16SrRNA gene.Bacterial abundance and diversity were significantly lower in CAG cases than in controls (p 0.001). Firmicutes were more frequent in cases, Bacteroidetes and Fusobacteria in controls (p 0.0001). Streptococcaceae were more abundant in cases (p 0.0001), Prevotellaceae in controls (p 0.0001). The genus Streptococcus was positively correlated with severe OLGA/OLGIM stages linked to a higher risk of gastric cancer.Gastric bacterial microbiota in CAG showed a reduced abundance and complexity but was characterized by higher colonization of Firmicutes, in particular Streptococcus, increased in subjects with severe atrophy/metaplasia stages at higher risk of gastric cancer.

Caustic ingestion can lead to structural changes in the upper gastro-intestinal tract. However, there is limited data on the effect of caustic ingestion on gastric secretion. This study was planned to determine changes in gastric acid output after sham feeding in patients with caustic induced esophageal stricture and to compare it with healthy controls. It was a prospective study done at tertiary care center in North India. Consecutive patients with caustic induced esophageal stricture were evaluated for the study. Gastric secretory function was estimated in the basal state and after modified sham feeding. These results were compared with age-matched controls. The mean age of the included patients (n = 18) was 30.11 ± 9.19 years and 13 patients were male. 16 (88%) patients had history of acid ingestion. Patients with caustic sequelae had significantly lower basal and stimulated acid secretion compared to controls (n = 10) (5.84 ± 2.44 mmol/hr; p

Coronavirus disease 2019 (COVID‐19) is caused by severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) which emerged in Wuhan, China in 2019 (1). Respiratory symptoms remain the most common clinical manifestations of COVID‐19. However, non‐respiratory symptoms are increasingly being recognized. Gastrointestinal (GI) symptoms such as anorexia, nausea, vomiting, diarrhea, and abdominal pain are noted in COVID‐19 patients either alone or in association with respiratory manifestations (2). Stool viral RNA can be detected by up to 50% in patients with diarrhea (3). This article is protected by copyright. All rights reserved.

Highlights • Gastrointestinal symptoms like diarrhea sometimes occur in COVID-19 disease • Fecal samples from COVID-19 patients sometimes test positive for COVID-19 markers • COVID-19 virus can survive pH 3-5 typical of gastric environment in hypochlorhydria • COVID-19 virus could escape the hypochlorhydric stomach and infect the intestine • COVID-19 Fecal-oral transmission in addition to airborne should be considered, COVD-19 disease is characteristically respiratory in nature; however, some patients have gastrointestinal symptoms. These include changes in taste, nausea/vomiting, abdominal pain, and diarrhea. A report has been published of a young patient who repeatedly tested positive in stool samples while nasopharyngeal tests remained negative. This raises doubts about our understanding of the dynamics of COVID-19 disease. The current report describes a need for selective stool testing to explore fecal shedding of viral RNA and presents a hypothesis for direct infection of enterocytes in cases of hypochlorhydria.

The long-term use of proton pump inhibitors (PPIs) can lead to increased gastric pH, hypochlorhydria and in some cases to achlorhydria when compared to other acid-suppressing agents like histamine-2 (H2) receptor blockers and antacids. These consequences by the use of long-term PPIs may lead to significant vitamin (B12 and C) and mineral (iron, calcium and magnesium) deficiencies which needs gastric acid for their absorption and bioavailability. Long-term use of PPIs by the pregnant patients may impose a potential risk of congenital malformations. Various studies have recommended the life style modifications and antacid use as first choice among pregnant womens by preserving PPIs (omeprazole as a safe choice of PPI) for severe conditions of gastroesophageal reflux disease. The long-term acid suppression by PPIs can also lead to enteric, respiratory and urinary tract infections. The hypochlorhydria by chronic PPIs use may induce hypergastrinemia, which ultimately mediates the gastric polyps, gastric carcinoids and gastric cancer. The concomitant use of PPIs with antiplatelet drugs like clopidogrel can impose the patients to major adverse cardiac events. This review has enlisted the comprehensive information regarding the adverse effects induced by long-term use of PPIs and their possible relations. Considerable studies like case-control, randomized trials, cohort studies and meta-analysis were reported in supporting these adverse effects. The clinicians and patients should be cautious about these effects so that they can avoid the serious outcomes. PPIs should be avoided for long-term use mainly in older adults unless there is a proper indication.

Background & Aims In patients with autoimmune atrophic gastritis and achlorhydria, hypergastrinemia is associated with the development of type 1 gastric neuroendocrine tumors (gNETs). Twelve months of treatment with netazepide (YF476), an antagonist of the cholecystokinin B receptor (CCKBR or CCK2R), eradicated some type 1 gNETs in patients. We investigated the mechanisms by which netazepide induced gNET regression using gene expression profiling. Methods We obtained serum samples and gastric corpus biopsy specimens from 8 patients with hypergastrinemia and type 1 gNETs enrolled in a phase 2 trial of netazepide. Control samples were obtained from 10 patients without gastric cancer. We used amplified and biotinylated sense-strand DNA targets from total RNA and Affymetrix (Thermofisher Scientific, UK) Human Gene 2.0 ST microarrays to identify differentially expressed genes in stomach tissues from patients with type 1 gNETs before, during, and after netazepide treatment. Findings were validated in a human AGSGR gastric adenocarcinoma cell line that stably expresses human CCK2R, primary mouse gastroids, transgenic hypergastrinemic INS-GAS mice, and patient samples. Results Levels of pappalysin 2 (PAPPA2) messenger RNA were reduced significantly in gNET tissues from patients receiving netazepide therapy compared with tissues collected before therapy. PAPPA2 is a metalloproteinase that increases the bioavailability of insulin-like growth factor (IGF) by cleaving IGF binding proteins (IGFBPs). PAPPA2 expression was increased in the gastric corpus of patients with type 1 gNETs, and immunohistochemistry showed localization in the same vicinity as CCK2R-expressing enterochromaffin-like cells. Up-regulation of PAPPA2 also was found in the stomachs of INS-GAS mice. Gastrin increased PAPPA2 expression with time and in a dose-dependent manner in gastric AGSGR cells and mouse gastroids by activating CCK2R. Knockdown of PAPPA2 in AGSGR cells with small interfering RNAs significantly decreased their migratory response and tissue remodeling in response to gastrin. Gastrin altered the expression and cleavage of IGFBP3 and IGFBP5. Conclusions In an analysis of human gNETS and mice, we found that gastrin up-regulates the expression of gastric PAPPA2. Increased PAPPA2 alters IGF bioavailability, cell migration, and tissue remodeling, which are involved in type 1 gNET development. These effects are inhibited by netazepide., Graphical abstract

Iron deficiency (ID) workup is a common challenge for gastrointestinal endoscopy. In premenopausal women current guidelines recommend serologic evaluation of coeliac disease only. Here we systematically tested serologic screening for autoimmune gastritis (AIG) in a large cohort of patients with ID. This is a retrospective analysis of patients who attended an out-patient clinic specialized for ID. Patients with ferritin50 µg/L or transferrin saturation15% were included. Laboratory workup included endomysial antibodies and parietal-cell antibodies (PCA). Upper gastrointestinal endoscopy with pH-measurement of gastric juice and histology was performed to confirm positive serologic results. Three hundred seventy-three patients with ID were included, about half of whom were anemic. Patients were predominately female with a median age of 40 (confidence interval 11). Positive endomysial antibodies were found in 4 (1%) patients, elevated levels of PCA (20 U/mL) were found in 69 (18.5%) patients, PCA100 U/mL in 23 (6.2%). Twenty-six were followed up by gastroscopy; in 12 of 26 patients the diagnosis of AIG was confirmed by histology with 2 additional patients diagnosed as early and/or questionable AIG. A sensitivity of 93% and a specificity of 98% were estimated for a PCA cut-off of 100 U/mL. In 20 patients gastric pH was measured. Achlorhydria was found in 7 patients all diagnosed with AIG. In this ID cohort AIG is by far more common than coeliac disease. PCA above 100 U/mL are a sensitive and specific cut-off for workup of patients with ID prior to endoscopy. Serologic suspicion of AIG helps preselection of patients for endoscopic workup for ID.

Background Although autoimmune gastritis (AIG) is generally considered relatively rare, we frequently encounter AIG among patients at to our hospital who have experienced at least two episodes of Helicobacter pylori eradication failure. Aims We investigated the incidence of AIG in consecutive patients who consulted our department for H. pylori eradication with reference to eradication history. Methods A total of 404 consecutive patients who visited the H. pylori-specific out-patient unit of our hospital from June 2015 to June 2017 were enrolled. Of these, 137 were treatment-naive, 47 had failed treatment once (single failure), and 220 had failed treatment twice or more (multiple failures) by 13 C-UBT. Gastroscopy was performed in all patients. Culture tests of gastric mucosal samples were performed for H. pylori and other bacteria positive for urease activity. Anti-parietal cell antibody (APCA) was measured. Patients with severe atrophy in the gastric corpus and positivity for APCA were diagnosed as having AIG. Results A total of 43 patients were diagnosed as having AIG, of whom two were treatment-naive (1.5%, 2/137), 1 failed eradication once (2.1% 1/47), and 40 failed treatment at least twice (18.2%, 40/220). The incidence of AIG was significantly higher in the multiple failure group than in the single failure or treatment-naive groups. Urease-positive bacteria, such as Klebsiella pneumoniae and alpha-streptococcus, were identified in 33 of the 35 AIG patients who underwent culture testing. Conclusion AIG patients were often misdiagnosed as refractory to eradication therapy, probably because achlorhydria in AIG might allow urease-positive bacteria other than H. pylori to colonise the stomach, causing positive 13 C-UBT results.

Pernicious anemia (PA) develops from atrophic gastritis due to autoimmune destruction of parietal cells and results in achlorhydria, vitamin B12 and iron deficiencies, anemia, neurologic deficits, and premalignant and malignant stomach lesions. We report the presentation, diagnosis and gastric complications of PA in patients from an endocrinology practice.Thirty-four patients (31 female, 3 male) with PA who underwent esophagogastroduodenoscopy (EGD) or gastrectomy were identified. Pertinent clinical, laboratory, and pathology findings were reviewed and summarized.The mean age of patients was 58.6 ± 14.2 years; the onset of PA was age 50.2 ± 15.3 years. Anemia reflected vitamin B12 and/or iron deficiencies. Parietal cell antibodies (PCA) were detected in 97% of patients, and intrinsic factor blocking antibody (IFBA) was found in 52%. Fasting gastrin and chromogranin A levels were elevated (1,518.0 ± 1,588.3 pg/mL, and 504.9.1 ± 1,524.9 ng/mL respectively). Autoimmune or immunologic diseases (AIDs) were present in 32/34 patients. Stomach pathology showed premalignant or malignant lesions in 26 patients, including gastric neuroendocrine tumors (GNETs) in 6 and adenocarcinoma in 1. One patient presented with neurologic symptoms and subacute combined degeneration of the posterior column of the spinal cord.PA should be suspected in patients with unexplained anemia or neurologic symptoms. The diagnosis of PA relies on fasting gastrin and gastric auto-antibody testing, in addition to hematologic evaluation. EGD with measurement of gastric pH and biopsies of the fundus and antrum identifies patients with achlorhydria, atrophic gastritis, and premalignant and malignant stomach lesions. EGD surveillance of patients with high-risk stomach lesions is recommended.AID = autoimmune or immunologic disease; EGD = esophagogastroduodenoscopy; GNET = gastric neuroendocrine tumor; IFBA = intrinsic factor blocking antibody; PA = pernicious anemia; PCA = parietal cell antibody; T1D = type 1 diabetes.

OBJECTIVES: To document the existence of primary pancreatic secretinoma in patients with watery diarrhea syndrome (WDS) and achlorhydria and establish secretin as a diarrheogenic hormone. BACKGROUND: Vasoactive intestinal peptide (VIP) has been widely accepted as the main mediator of WDS. However, in 1968, Zollinger et al reported 2 female patients with pancreatic neuroendocrine tumors, WDS, and achlorhydria. During surgery on the first, a 24-year-old patient, they noticed distended duodenum filled with fluid and a dilated gallbladder containing dilute bile with high bicarbonate concentration. After excision of the tumor, WDS ceased and gastric acid secretion returned. The second, a 47-year-old, patient’s metastatic tumor extract given intravenously in dogs, produced significantly increased pancreatic and biliary fluid rich in bicarbonate. They suggested a secretin-like hormone of islet cell origin explains WDS and achlorhydria. These observations, however, predated radioimmunoassay, immunohistochemical staining, and other molecular studies. METHODS: The first patient’s tumor tissue was investigated for secretin and VIP. Using both immunohistochemistry and laser microdissection and pressure catapulting technique for RNA isolation and subsequent reverse transcription polymerase chain reaction, the expression levels of secretin, and VIP were measured. RESULTS: Immunoreactive secretin and its mRNA were predominantly found in the tumor tissue whereas VIP and its mRNA were scarce. CONCLUSIONS: The findings strongly support that the WDS and achlorhydria in this patient may have been caused by secretin as originally proposed in 1968 and that secretin may act as a diarrheogenic hormone.

Background: Studies have found an association between proton pump inhibitor (PPI) use and Clostridium difficile infection. The purpose of this study was to determine whether the mechanism by which PPIs induce an increased risk of C. difficile infection is supported by the same mechanism acting in another cause of achlorhydria, pernicious anaemia. Methods: Using a database of anonymised primary care records between 1990 and 2013, we selected exposed patients with a diagnosis of pernicious anaemia treated with vitamin B12 therapy. Each exposed patient was matched by age, gender and general practice to up to 10 controls. Cox regression analysis was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for C. difficile infection with pernicious anaemia, adjusted for potential confounders. Results: We identified 45,467 exposed patients matched to 449,635 controls. The crude incidence rate of C. difficile infection was 1.85/1000 person-years for the exposed cohort and 1.09/1000 person-years for controls. Patients with pernicious anaemia had a greater risk of C. difficile infection than the controls (adjusted HR 1.57, 95% CI 1.40–1.76). Conclusions: Pernicious anaemia patients have an increased risk of C. difficile infection. This supports the theory that severe achlorhydria is the mechanism that increases the risk of C. difficile infection in long-term PPI users.

The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25−70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are 10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10−20 years). Zollinger−Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in

Type I gastric neuroendocrine tumors (gNETs) arise from hypergastrinemia in patients with autoimmune chronic atrophic gastritis. According to the classical model, the gastric H+/K+ ATPase was the causative autoantigen recognized by CD4+ T cells in chronic autoimmune scenario that secretes IL-17 and correlates with parietal cell (PC) atrophy, which drives to gastric achlorhydria and increases the risk for gastric neoplasms. However, the mechanism by which the inflammatory response correlates with PC atrophy is not clearly defined. Recently, we found that the ATP4Ap.R703C mutation impaired PC function and gastric acidification, which drove familial gNET. Our group constructed a knock-in mouse model for the ATP4A mutation, which has served us to better understand the relation between impaired capability to export protons across the plasma membrane of PCs and tumor progression. The ATP4Ap.R703C mutation drives gastric achlorhydria, but also deregulates the acid–base balance within PCs, affecting mitochondrial biogenesis. Mitochondrial malfunction activates ROS signaling, which triggers caspase-3-mediated apoptosis of parietal cells. In addition, when gastric euchlorhydria was restored, mitochondrial function is recovered. Infection by H. pylori promotes destabilization of the mitochondria of the PCs by a mechanism similar to that described for APT4Ap.R703C carriers. A genetic origin that drives mitochondria alteration would initiate the gastric chronic inflammation instead of the classical IL-17 secretion-mediated mechanism explanation. Gastric euchlorhydria restoration is suggested to be indicated for mitochondrial recover. Our results open a new window to understand gastric neoplasms formation but also the inflammatory mechanisms and autoimmune disorders conducted by genetic origin that composes a premalignant scenario.

The diagnosis of gastric neuroendocrine tumors (NETs) is being made with increased frequency likely as a result of more upper endoscopies being done for unrelated reasons. It is therefore vital that gastroenterologists become familiar with the basic work-up and management of patients found to have these tumors. This review describes the classification, pathophysiology, clinical characteristics, and treatment options of the different gastric NETs. In addition to the three traditional subtypes of gastric NETs, additional cases associated with achlorhydria and appropriate hypergastrinemia may exist. The management of gastric NETs between 1 and 2 cm in size remains controversial and needs to be individualized. Gastric NETs are uncommon but are now diagnosed more frequently. This review highlights the role of hypergastrinemia in their development and the controversies around their management.

Subacute combined degeneration (SCD) is a relatively rare myelopathy mainly caused by vitamin B12 (VitB12) deficiency. There are many causes contributing to VitB12 deficiency. Autoimmune gastritis might lead to severe VitB12 malabsorption and in its advanced stage pernicious anemia (PA) may occur. Besides, long-term hypergastrinemia arising from achlorhydria in autoimmune gastritis is associated with neuroendocrine tumors (NETs). Patients diagnosed with SCD coexistent with PA and NET are seldomly reported. We describe a 34-year-old woman with an initial complaint of progressive fatigue, weakness and numbness in her limbs and disturbed gait. Physical examination revealed appearance of anemia, ataxia, decrease of superficial and deep sense, and positive Babinski's sign. Laboratory tests disclosed macrocytic anemia, elevated intrinsic factor antibody and spinal MRI showed extensive T2-weighted hyperintensity in the dorsal columns. A gastric polyp was revealed by gastroscopy and histology showed an NET in the background of severe atrophic gastritis. Symptoms of the patient were relieved by a multidisciplinary therapy. In patients with SCD, PA should be suspected and prompt further investigations to elucidate causes and direct treatment.

Gastrin exerts trophic effects on all cells of the gastric oxyntic mucosa including enterochromaffin-like (ECL) cells. Hypergastrinemia may result from hypoor achlorhydria due to chronic atrophic gastritis, from longterm drug-induced acid suppression or from gastrinoma occurring as part of the multiple endocrine neoplasia (MEN) 1 syndrome [1]. We describe here a man who developed an atypical, benign gastric carcinoid or neuroendocrine tumor (NET), after being treated with a proton pump inhibitor (PPI) for 20 years.

Chronic atrophic gastritis is a generally asymptomatic condition of great importance because it develops into gastric cancer in a number of patients. It is described as an atrophy of the gastric mucosa. There are two types of atrophic gastritis: a gastric body predominant type in patients with infection of Helicobacter pylori, and an autoimmune type, limited to the gastric body and fundus. The autoimmune type is quite rare and affects people of all ethnicities. Globally, H. pylori infection is very common and is considered a class I carcinogen due to the large number of patients who subsequently develop gastric cancer. The pathogenesis of the autoimmune type involves an antibody-mediated loss of parietal cells resulting in achlorhydria and an antibody-mediated loss of intrinsic factor that causes pernicious anemia. The diagnosis of H. pylori infection is based on endoscopy and culture of the organisms. Patients with atrophic gastritis as well as H. pylori infection should be treated with antibiotics to eradicate the organism. Patients with the autoimmune type need to be evaluated for anemia, and if present, treated with vitamin B12.

Chronic autoimmune atrophic gastritis (CAAG) is an organ-specific autoimmune disease, which affects the corpus-fundus gastric mucosa. Although it has been described for several years, the real pathophysiological mechanisms, the natural history and the possible neoplastic complications are not completely known. Atrophy of the gastric mucosa is the endpoint of the chronic processes, with the loss of glandular cells and their replacement by intestinal-type epithelium, pyloric-type glands, and fibrous tissue. As a consequence, hydrochloric acid, pepsin and intrinsic-factor is impaired resulting in pernicious anemia. The exact causal agent is not yet known, but both genetic and environmental factors seem to play a decisive role. Moreover, the clinical onset may assume different characteristics; differently from what previously observed, recent evidence has reported the onset of CAAG at a younger age, frequently with iron deficiency anemia or upper gastro-intestinal symptoms. The diagnosis of CAAG might be challenging and usually requires the combination of clinical, serological and histopathologic data; moreover, CAAG patients are often misdiagnosed as refractory to HP eradication therapy, probably because achlorhydria might allow urease-positive bacteria other than H pylori to colonize the stomach, causing positive 13C-urea breath test results. However, biopsy is the most reliable method to evaluate the presence of metaplastic atrophic gastritis. In order to assess the severity of gastric atrophy and intestinal metaplasia, OLGA and OLGIM staging systems have been proposed and seem to correlate with the risk of developing gastric adenocarcinoma. Indeed, CAAG represents a pre-neoplastic condition, as patients with CAAG are very likely to develop either type-1 gastric neuroendocrine tumors and gastric adenocarcinomas, as well as several other neoplastic diseases. To date, the need, the intervals and cost-effectiveness of endoscopic/histological surveillance for patients with CAAG/pernicious anemia are yet to be established.

Background Autoimmune metaplastic atrophic gastritis is a chronic progressive inflammatory condition. The clinical spectrum includes pernicious anemia, atrophic gastritis, antibodies to parietal cell antigens and intrinsic factor, achlorhydria, hypergastrinemia and carcinoma. It is rare in paediatric cohorts. Case presentation We present the case of a boy with metaplastic atrophic gastritis in whom immune dysregulation, polyendocrinopathy, enteropathy, X-linked(IPEX) syndrome was confirmed by FOXP3 gene mutation. The patient was referred to the hospital at the age of 3 years with recurrent emesis, diarrhoea and malnutrition. His elder brother died at 9 years of age from acute respiratory distress syndrome and renal tubular acidosis. The patient was allergic to cow milk formula and noodles. Oesophagegastroduodenoscopy revealed redness, erosion and edema throughout the stomach; whitish granules in the duodenal bulb; and edema in the second part of the duodenum. Biopsies showed extensive villous atrophy and goblet cell depletion in the duodenum. He was diagnosed with type-1 diabetes mellitus (T1DM) during the treatment of methylprednisolone. Serum antibodies against glutamic acid decarboxylase and pancreatic islets were detected. The patient’s FOXP3 gene was sequenced; this identified that the patient was hemizygous for a pathogenic variant [NM_014009.3:c.748_750del (p.Lys250del)]. Conclusion Metaplastic atrophic gastritis is rarely reported in patients with IPEX. Clinical gastroenterologists should be aware of IPEX syndrome when facing the complex syndromes of metaplastic atrophic gastritis and endocrinopathy.

Vasoactive intestinal polypeptide-secreting tumors (VIPomas) are rare neuroendocrine tumors that often present as watery diarrhea, hypokalemia, and achlorhydria or hypochlorhydria. In this study, we present our institutional experience of diagnosis and treatment of VIPomas, along with a review of the Chinese literature since 1980. Patient #1, diagnosed in 1984 and with intact clinical records, shows the natural history of this disease. Patient #2, diagnosed in 2015, shows the results of evaluation by nuclear medicine techniques and the outcomes of standardized treatment. Comprehensive review of 41 cases allows evaluation of clinical characteristics, treatments and outcomes of pancreatic VIPoma patients. All patients presented with watery diarrhea. The average stool volume reached 3247 mL per day. Average serum VIP level was 839.3 ng/L. Twelve of the 41 cases were reported to have metastases at diagnosis. Somatostatin receptor scintigraphy and 18FDG PET-CT are efficient methods for detection of VIPoma. Surgical excision can promptly alleviate hormonal symptoms.

VIPoma, Verner-Morrison syndrome, is a rare functioning neuroendocrine tumor that secretes vasoactive intestinal polypeptide (VIP). It is also known as pancreatic cholera or WDHA syndrome (watery diarrhea, hypokalemia and hypo or achlorhydria). Verner and Morrison first described the symptoms of VIPoma in 1958 as watery diarrhea, hypokalemia and achlorhydria [1]. Approximately 90 % of cases arise from the pancreas but they may also occur in periganglionic tissue or other locations such as the adrenals, colon, bronchus, liver and sympathetic ganglia. VIPomas are found to be malignant in about 60–80 % cases and are metastatic at the time of diagnosis, with the liver being the most common site of metastasis [2]. Herein, we present a patient with chronic diarrhea who was found to have VIPoma and did well after surgical resection.

Background: Helicobacter pylori-infection has been associated with an imbalance of iron homeostasis. IL-1 has been related with iron absorption disturbances through a variety of mechanisms. The aim of this study was to evaluate the presence of polymorphic variants for IL-1 cluster and gastric IL1β mRNA expression in H. pylori-infected children and their relationship with hypoclorhydria and iron deficiency (ID). Patients and Methods: Prospective study of 123 symptomatic children. At endoscopy, antral biopsies were taken for urease test, pathology and culture and blood for analysis of ferritin, transferrin, serum iron and total iron-binding capacity. Polymorphisms in the IL-1 cluster (positions -511, -31, +3954, ILRN) were determined by PCR-RFLP. Gastric mucosal expression of IL-1 mRNA was determined by RT-PCR. Results: After exclusions, out of 105 patients, 33 (31.4%) were H. pylori positive. Nine (8.6%) children were classified as iron deficient (ID). H. pylori positivity was associated with ID (OR: 5.1; 95% CI: 1.2-21.9) (p = 0.04). No significant differences were found in allele frequency for IL1β gene cluster polymorphisms between infected and uninfected children. H. pylori-infected children with ID had significantly increased gastric IL1β mRNA in comparison to infected children without ID. In addition a significant positive correlation was observed between mucosal IL-1β mRNA and fasting gastric juice pH. Gastric pH values were significantly increased in H. pylori infected patients with ID compared to uninfected children. Conclusions: The established association between H. pylori infection and ID in children may be mediated by increased gastric mucosal IL-1.

We re-evaluated the old hypothesis that gastritis-induced achlorhydria is a cause of iron deficiency anemia (IDA) in humans. First, we analyzed the currently available research on the association between achlorhydria and IDA. When gastric acid secretion was measured after maximal stimulation, the frequency of achlorhydria (or severe hypochlorhydria) was 44% in patients with idiopathic IDA and 1.8% in healthy controls. In some patients with pernicious anemia, presumed achlorhydria preceded the development of IDA in time. However, we found no credible evidence that IDA caused gastritis or that IDA preceded the development of achlorhydria. Thus, correlational results favor achlorhydria as the causal factor in the association between achlorhydria and IDA. Second, we sought to determine whether gastritis and achlorhydria cause negative iron balance. When biosynthetic methods were used to isotopically label iron in food, achlorhydric patients were found to have severe malabsorption of nonheme iron, which persisted after the development of IDA. In 1 study, achlorhydria reduced the normal increase in heme-iron absorption from hemoglobin in response to iron deficiency. After an injection of isotopic iron into normal men, the physiologic loss of iron from the body was found to be 1 mg/d. Patients with chronic gastritis had excess fecal loss of isotopically tagged plasma iron. Calculations based on these results indicate that the absorption of iron from a typical Western diet by achlorhydric patients would be less than physiologic iron losses, creating a negative iron balance that could not be overcome by the adaptive increase in duodenal iron absorptive capacity that occurs in response to iron deficiency. The combination of results from these correlational and pathophysiologic studies supports the hypothesis that gastritis-induced achlorhydria can be an independent cause of IDA.

The aim of this study was to determine the prevalence of iron deficiency among patients with pernicious anemia. We realized a retrospective study from 2000 to 2010 including 55 patients suffering from pernicious anemia who were followed in Reims and Strasbourg university hospitals. Inclusion criteria were histological diagnosis of immune atrophic fundic gastritis and criteria of gastric autoimmuninty, and for which ferritin was measured. Iron deficiency is defined as serum ferritin level

Several conditions associated with reduced gastric acid secretion confer an altered risk of developing a gastric malignancy. Helicobacter pylori-induced atrophic gastritis predisposes to gastric adenocarcinoma, autoimmune atrophic gastritis is a precursor of type I gastric neuroendocrine tumours, whereas proton pump inhibitor (PPI) use does not affect stomach cancer risk. We hypothesised that each of these conditions was associated with specific alterations in the gastric microbiota and that this influenced subsequent tumour risk. 95 patients (in groups representing normal stomach, PPI treated, H. pylori gastritis, H. pylori-induced atrophic gastritis and autoimmune atrophic gastritis) were selected from a cohort of 1400. RNA extracted from gastric corpus biopsies was analysed using 16S rRNA sequencing (MiSeq). Samples from normal stomachs and patients treated with PPIs demonstrated similarly high microbial diversity. Patients with autoimmune atrophic gastritis also exhibited relatively high microbial diversity, but with samples dominated by Streptococcus. H. pylori colonisation was associated with decreased microbial diversity and reduced complexity of co-occurrence networks. H. pylori-induced atrophic gastritis resulted in lower bacterial abundances and diversity, whereas autoimmune atrophic gastritis resulted in greater bacterial abundance and equally high diversity compared to normal stomachs. Pathway analysis suggested that glucose-6-phospahte1-dehydrogenase and D-lactate dehydrogenase were over represented in H. pylori-induced atrophic gastritis versus autoimmune atrophic gastritis, and that both these groups showed increases in fumarate reductase. Autoimmune and H. pylori-induced atrophic gastritis were associated with different gastric microbial profiles. PPI treated patients showed relatively few alterations in the gastric microbiota compared to healthy subjects., Author summary Different conditions such as autoimmune atrophic gastritis and Helicobacter pylori associated atrophic gastritis are associated with different types of gastric cancer, specifically neuroendocrine tumours and adenocarcinoma. Both conditions result in reduced gastric acid secretion, potentially allowing non-H. pylori bacteria to colonise the stomach. However patients receiving proton pump inhibitors (PPI) experience similar levels of acid secretion, but do not develop gastric cancer. The aims of this study were to investigate the contribution of non-H. pylori microbiota to gastric tumour development in the presence of reduced gastric acid secretion. 16S rRNA sequencing identified relatively few alterations in the gastric microbiota in patients receiving PPI therapy, despite reduced acid secretion, but more substantial alterations in those patents who had atrophic gastritis. Significant differences were also found between the patients who had atrophic gastritis of autoimmune and H. pylori associated types. Differences in biochemical pathways that potentially contribute to gastric tumorigenesis were also predicted. This work increases understanding of the mechanisms involved in gastric tumour development, and demonstrates how non-H. pylori bacteria may be important. This work may eventually lead to the development of novel chemopreventive therapies for stomach cancer that are based on altering the composition of the gastric microbiota.

Introduction Human Immunodeficiency Virus (HIV) infection is associated with hypochlorhydria but the mechanism is unknown. The objective of this study was to determine effects of anti-retroviral therapy (ART) on gastric physiology as measured by validated markers. Methods We studied HIV infected individuals who were either ART-naive or on treatment with undetectable viral loads. We measured H.pylori IgG antibodies, pepsinogen (PG) 1 and 2 levels and fasting gastrin-17 using Biohit GastroPanel®. Gastric antral biopsies and juice were obtained for histology and pH respectively. Also included were historical data from HIV negative participants (n = 72) in a previous study, for reference. Results We enrolled 84 HIV positive individuals with a median age 42 years (IQR 37-40 years). 55(66%) were female, 32(38%) were ART naive, and 52(62%) were on ART. Hypochlorhydria (pH>4) was present in 48(57%) of the HIV positive and 18(25%) of the HIV negative individuals (OR 4: 95% CI 1.9-8.5, P

The use of proton pump inhibitors (PPIs) in the treatment of gastrointestinal diseases has evolved over recent years. Initially intended for short-term use, PPIs are increasingly being used, often inappropriately, as long-term maintenance medications. The mechanism of action of PPIs is suppression of gastric basal and stimulated acid secretion by inhibiting the parietal cell H+/K+ ATP pump with a resultant increase in gastric pH and hypo- or achlorhydria. Although short-term use is related to few adverse effects, long-term use is associated with numerous complications. We present the case of a 58-year-old man with severe iron deficiency anemia due to malabsorption suspected to be caused by long-term PPI use. An extensive medical work up failed to reveal any definitive source of bleeding. An iron malabsorption test confirmed that iron was not being absorbed from the gastrointestinal tract. The Naranjo Adverse Drug Reaction Probability Scale and the Horn and Hansten Drug Interaction Probability Scale are suggestive of an association between long-term PPI use and the observed iron deficiency anemia. However, the patient's death and lack of an autopsy prevented confirmatory follow-up data from being obtained to connect long-term PPI use as the culprit. Although there are currently no recommendations regarding screening for iron deficiency and/or anemia in patients on long-term PPI therapy, physicians should be aware of this potential side effect and consider monitoring in high-risk patients.

Achlorhydria is defined as a decrease in secretion quantity or decrease in the acidity of gastric acid. Gastric acid has several functions including activating other digestive enzymes, deciphering the food particles in the digestive process, essential vitamins and minerals absorption, and eliminating most of the microorganisms that enter with the food. There is no specific management for achlorhydria. Patients with achlorhydria in addition to experiencing disorders of HCl formation generally also suffer from pepsin deficiency. Therefore, pepsin is usually given to support the provision of betaine HCl. Patients with achlorhydria should be periodically monitored for early diagnosis of anemia due to iron deficiency and/or cobalamin. Calcium and vitamin D deficiency can be monitored through serum 25 hydroxyvitamin D level as well as bone density examination

Review of the physiology of acid secretion and main consequences of reduced secretion of gastric acid. Short- and long-term effects both from pathology and medically induced hypochlorhydria are discussed.

Background: Transmission of Helicobacter pylori occurs within families. It is known that elimination of H. pylori may reduce the risk of peptic ulcer disease (PUD) and gastric cancer (GC) and increase the risk of gastro-esophageal reflux (GERD), Barrett’s esophagus, and esophageal adenocarcinoma. Objectives: The present study aimed to determine gastric cancer-related strains of H. Pylori by precise diagnostic methods in patients with gastritis and PUD in East Azerbaijan, Iran, where the incidence of GC and esophageal cancer is high. Methods: The PCR assay was performed on the same biopsy samples used for Campylobacte-like organism test (CLO test), using the vacA d region (a gene predictor of gastric adenocarcinoma and peptic ulcer disease) and 16S rDNA gene in patients referring to the department of endoscopy at Imam Reza hospital in Tabriz, Iran. This study was conducted on individuals who had not received non-steroidal anti-inflammatory drugs or any anti-Helicobacter therapy at least for 3 months prior to endoscopy. The collected data were analyzed using SPSS version 19. Results: The rate of false negative results by CLO test was 8.3%. However, no false-positive results were found by CLO test. Among those patients infected with H. pylori, vacA d1 -positive strains, one case had a history of gastric cancer and another one had a history of gastric ulcer in first-degree relatives. However, no family history of gastric cancer or gastric ulcer was found in the patients with strains carrying the vacA d2 genotype. Conclusions: This study suggests that the vacA PCR can be very useful in diagnosis, treatment, and follow-up of patients with gastritis and PUD. The PCR assay and CLO test can complement and confirm each other in identification and eradication of cancer-related strains of H. pylori. The exclusion of patients with suspected achlorhydria from the study is likely a reason for the lack of false positive results in CLO test.