Management of Gastric Neuroendocrine Tumors: A Review.

Gastric neuroendocrine tumors (G-NET) are rare tumors arising from enterochromaffin-like cells of the gastric mucosa. They belong to a larger group called gastroenteropancreatic neuroendocrine tumors and are classified as low, intermediate, or high-grade tumors based on their proliferative indices. They are further categorized into three subtypes based on their morphologic characteristics, pathogenesis, and behavior. Types 1 and 2 tumors are characterized by elevated serum gastrin and are usually multifocal. They typically occur in the setting of atrophic gastritis or MEN1/Zollinger Ellison syndrome, respectively. Type 2 tumors are associated with the most symptoms, such as abdominal pain and diarrhea. Type 3 tumors are associated with normal serum gastrin, are usually solitary, and occur sporadically. This type has the most aggressive phenotype and metastatic potential. Treatment and prognosis for G-NET is dependent on their type, size, and stage. Type 1 has the best prognosis, and Type 3 has the worst. This review discusses the presentation, workup, and surgical management of these tumors.

MENIN-mediated regulation of gastrin gene expression and its role in gastrinoma development.

The Multiple Endocrine Neoplasia I (MEN1) locus encodes the protein MENIN, which functions as a tumor suppressor protein in neuroendocrine tissues. Gastrinomas are neuroendocrine neoplasms that overproduce the hormone gastrin and can arise sporadically or as part of the MEN1 syndrome, in which mutations in the MEN1 gene lead to loss or inactivation of MENIN protein. Gastrin is a peptide hormone that is primarily synthesized in the gastric antrum and stimulates the secretion of histamine from enterochromaffin-like (ECL) cells and subsequently acid from parietal cells in the gastric corpus. In addition, gastrin exerts a mitogenic function primarily on ECL cells and progenitor cells in the gastric isthmus. Current studies seek to understand how MEN1 mutations generate a mutant MENIN protein that abrogates its tumor suppressor function. Mutations in the MEN1 gene are broadly distributed throughout its nine protein-coding exons, making it difficult to correlate protein structure with its function. Although disruption of the Men1 locus in mice causes functional neuroendocrine tumors in the pituitary and pancreas, gastrinomas do not develop in these transgenic animal models. Prior studies of human gastrinomas suggest that tissue-specific microenvironmental cues in the submucosal foregut may contribute to tumorigenesis by reprogramming of epithelial cells toward the neuroendocrine phenotype. Accordingly, recent studies suggest that neural crest-derived cells are also sensitive to reprogramming when MEN1 is deleted or mutated. Thus, the goal of this report is to review our current understanding of how MENIN modulates gastrin gene expression while highlighting its role in the prevention/suppression of neuroendocrine cell transformation.

The cckOMA syndrome and its relation to the Zollinger-Ellison syndrome: a diagnostic challenge.

OBJECTIVE: Among patients with enteropancreatic neuroendocrine tumor syndromes only one case with a cholecystokinin (CCK) secreting tumor has been reported. She had significant hyperCCKemia leading to a specific syndrome of severe diarrheas, weight loss, repeated duodenal ulcers and a permanently contracted gallbladder with gallstones. There are, however, reasons to believe that further CCKomas exist, for instance among Zollinger-Ellison patients with normal plasma gastrin concentrations. The present review is a call to gastroenterologists for awareness of such CCKoma patients. METHOD: After a short case report, the normal endocrine and oncological biology of CCK is described. Subsequently, the CCKoma symptoms are discussed with particular reference to the partly overlapping symptoms of the Zollinger-Ellison syndrome. In this context, the diagnostic use of truly specific CCK and gastrin assays are emphasized. The discussion also entails the problem of access to accurate CCK measurements. CONCLUSION: Obviously, the clinical awareness about the CCKoma syndrome is limited. Moreover, it is also likely that the knowledge about the necessary specificity demands of diagnostic gastrin and CCK assays have obscured proper diagnosis of the CCKoma syndromes in man.

Omeprazole taken once every other day can effectively prevent aspirin-induced gastrointestinal mucosal damage in rats.

BACKGROUND: Proton-pump inhibitors (PPIs) prevent aspirin-associated gastric and duodenal mucosal damage. However, long-term use of PPIs can lead to various adverse reactions, such as gastric polyps and enterochromaffin-like cell hyperplasia. Current research indicates that the abovementioned adverse reactions are mainly related to hypergastrinemia. We investigated whether low-frequency administration of omeprazole could effectively repair aspirin-induced mucosal damage and reduce the increase in gastrin levels associated with long-term use of PPIs. METHODS: Sprague‒Dawley rats were divided into four treatment groups: daily aspirin, daily aspirin and omeprazole once every day (qd), daily aspirin and omeprazole once every other day (qod), and daily aspirin and omeprazole once every three days (1/d3). After 15 days of feeding, blood samples were collected, and the stomachs of sacrificed rats were subjected to macroscopic, histological, and immunohistochemical studies. Moreover, in clinical practice, patients with peptic ulcers caused by aspirin took a standard dose of omeprazole (20 mg) every other day. Two months later, gastroscopy was performed to examine the healing of the ulcers. RESULTS: Both the omeprazole qd and omeprazole qod administrations effectively prevented aspirin-induced gastric peptic ulcers, with no significant difference between the two groups in the inhibition of parietal cell secretion of gastric acid and cell apoptosis. However, omeprazole 1/d3 failed to completely prevent aspirin-induced gastric mucosal injury. Notably, the gastrin levels, cell proliferation ability and cholecystokinin B receptor expression of the omeprazole qd group were significantly higher than those of the omeprazole qod group. In clinical work, patients with peptic ulcers caused by aspirin were given a standard dose of omeprazole every other day, and their ulcers healed after 2 months, as observed by gastroscopy. CONCLUSIONS: Omeprazole administration once every other day can effectively prevent aspirin-induced peptic ulcers and reduce hypergastrinemia, which may reduce the long-term adverse effects of PPI treatment.

Aloe vera gel confers therapeutic effect by reducing pyroptosis in ethanol-induced gastric ulcer rat model: Role of NLRP3/GSDMD signaling pathway.

BACKGROUND: Gastric ulcer (GU) is a common gastrointestinal tract illness. Aloe vera has anti-inflammatory, antioxidant, and healing characteristics. This research sought to explore the therapeutic impact of Aloe vera gel on ethanol-provoked GU in rats and to elucidate the underlying mechanisms involved. METHODS: An ethanol-induced GU rat model was constructed using forty male Wistar rats distributed at random into four groups: control, ulcer, pantoprazole, and Aloe vera. Gross evaluation of the stomach, ulcer index (UI), inhibition index, and gastric pH estimation were analyzed. Gastric malondialdehyde (MDA) and reduced glutathione (GSH) were determined using the spectrophotometric method, and serum gastrin level was measured by an enzyme-linked immunosorbent assay. Gastric nucleotide-binding domain, leucine-rich repeat, and pyrin domain PYD containing protein 3 (NLRP3) and gasdermin D (GSDMD) mRNA expression levels were estimated by quantitative real-time PCR. Finally, the histopathological examination of the glandular part of stomach tissue was done. RESULTS: The ulcer group revealed a significant increase in MDA, gastrin, NLRP3, and GSDMD and a decrease in gastric pH and GSH compared to the control group. Gross investigations of the ulcer group revealed a hemorrhagic lesion in the stomach and an increase in UI. Also, histopathological results for this group showed severe epithelial loss, haemorrhage, inflammatory cell infiltration, and blood vessel congestion. However, Aloe vera treatment improved the gross, biochemical, molecular, and histopathological alterations induced by ethanol when compared to the ulcer group. CONCLUSIONS: Aloe vera exerted antiulcer activities through modulation of oxidant/antioxidant status, anti-secretory properties, and mitigation of pyroptosis.

B12 deficiency-related glossitis is highly associated with high gastrin-17 and low pepsinogen I.

BACKGROUND: The causes of vitamin B12 (B12) deficiency are varied and mainly related to gastric disorders. Glossitis is a common oral manifestation of B12 deficiency and is often first seen by dentists. This study aimed to investigate the correlation between B12 deficiency-related glossitis (B12-def glossitis) and gastric serum biomarkers [gastrin-17(G17), pepsinogen I (PGI), pepsinogen II (PGII), and anti-Helicobacter pylori (H. pylori) antibodies], and preliminarily discuss the etiology of B12-def glossitis. METHODS: A cross-sectional study was conducted in patients complaining of glossodynia, burning sensation, or severe recurrent oral ulcers, but patients with a history of gastrectomy were excluded. All subjects underwent a uniform oral examination and hematological tests. RESULTS: Of 243 patients, 133 with B12-def glossitis were in the case group, and 110 with other oral mucosal diseases (non-glossitis) and normal B12 levels were in the control group. In the case group, 84.2% (112/133) showed high G17 and low PGI levels (G17hi PGIlow ). Univariate logistic regression showed that G17hi PGIlow was a high-risk factor for B12-def glossitis (OR: 92.44; 95% CI: 35.91, 238.02). Subgroup analyses in the case group showed that the G17hi PGIlow group presented with lower B12 levels and a lower positive rate of anti-H. pylori antibodies compared to the non-G17hi PGIlow group. CONCLUSION: Gastric serum biomarkers in patients with B12-def glossitis generally showed G17hi PGIlow , suggesting possible atrophy of gastric corpus and fundus mucosa. The G17hi PGIlow and non-G17hi PGIlow groups may represent different etiologies of B12 deficiency.

Modern Management of Gastric Neuroendocrine Neoplasms.

OPINION STATEMENT: Gastric neuroendocrine neoplasms (G-NENs) are a heterogeneous group of tumors that broadly fall into two groups. The first group, driven by oversecretion of gastrin, are generally multifocal, small, and behave indolently with a low (but non-zero) risk of progression and metastatic spread. They are conventionally categorized into type 1, with endogenous gastric-based overproduction of gastrin, and type 2 G-NEN, with overproduction of gastrin from an extra-gastric gastrin-secreting tumor. The second group, termed type 3 G-NEN, occur spontaneously and are potentially more aggressive, having a clinical course analogous to other neuroendocrine tumors of the gastrointestinal tract. Type 1 G-NEN can be managed with endoscopic surveillance and resection of visible lesions with great success, reserving surgery for the rare high-risk lesion, whereas surgical resection of the causative gastrin-secreting tumor in type 2 G-NEN is usually curative. Type 3 G-NEN is usually managed with formal surgical resection but there is growing evidence that limited surgery or even endoscopic resection in appropriately selected patients with low risk is both safe and effective. A novel subtype of G-NEN, associated with long-term proton pump inhibitor usage, is increasing in incidence. The pathophysiology seems to parallel type 1 G-NEN. In the setting of metastatic disease, which can occur in any subtype but is most common by far in type 3 G-NEN, the lack of trial data unique to G-NEN results in extrapolation of strategies and agents for treatment of non-gastric neuroendocrine disease. The rapid pace of development in this area is likely to benefit the metastatic G-NEN patient as well. As treatment is predicate on type of G-NEN, establishing the etiology of the lesion is crucial but growing knowledge of G-NEN pathophysiology and close collaboration between pathologists, gastroenterologists, radiologists, surgeons, and oncologists have enabled a growing trend towards de-escalation and less-invasive treatment paradigms.

Calcitonin levels in autoimmune atrophic gastritis-related hypergastrinemia.

PURPOSE: Calcitonin (Ct) is currently the most sensitive biochemical marker of C-cell disease (medullary thyroid cancer [MTC] and C-cell hyperplasia), but its specificity is relatively low. Our aim was to examine whether autoimmune atrophic gastritis (AAG) and chronic hypergastrinemia, with or without chronic autoimmune thyroiditis (AT), are conditions associated with increased Ct levels. METHODS: Three groups of patients were consecutively enrolled in this  multicentric study: group A consisted of patients with histologically-proven AAG (n = 13; 2 males, 11 females); group B fulfilled the criteria for group A but also had AT (n = 92; 15 males, 77 females); and group C included patients with AT and without AAG (n = 37; 6 males, 31 females). RESULTS: Median Ct levels did not differ between the three groups. Ct levels were undetectable in: 8/13 cases (61.5%) in group A, 70/92 (76.1%) in group B, and 27/37 (73.0%) in group C. They were detectable but ≤ 10 ng/L in 4/13 (30.8%), 20/92 (21.7%) and 7/37 (18.9%) cases, respectively; and they were > 10 ng/L in 1/13 (7.7%), 2/92 (2.2%) and 3/37 (8.1%) cases, respectively (P = 0.5). Only three patients had high Ct levels (> 10 ng/L) and high gastrin levels and had an MTC. There was no correlation between Ct and gastrin levels (P = 0.353, r = 0.0785). CONCLUSIONS: High gastrin levels in patients with AAG do not explain any hypercalcitoninemia, regardless of whether patients have AT or not. This makes it mandatory to complete the diagnostic process to rule out MTC in patients with high Ct levels and AAG.

Effects of remimazolam tosilate on gastrointestinal hormones and gastrointestinal motility in patients undergoing gastrointestinal endoscopy with sedation: a randomized control trial.

PURPOSE: To investigate the impacts of remimazolam tosilate on gastrointestinal hormones and motility in patients undergoing gastrointestinal endoscopy with sedation. METHODS: A total of 262 American Society of Anesthesiologists Physical Status I or II patients, aged 18-65 years, scheduled for gastrointestinal endoscopy with sedation, were randomly allocated into two groups (n = 131 each): the remimazolam tosilate group (Group R) and the propofol group (Group P). Patients in Group R received 0.2-0.25 mg/Kg remimazolam tosilate intravenously, while those in Group P received 1.5-2.0 mg/kg propofol intravenously. The gastrointestinal endoscopy was performed when the Modified Observer's Assessment of Alertness/Sedation scores were ≤3. The primary endpoints included the endoscopic intestinal peristalsis rating by the endoscopist; serum motilin and gastrin levels at fasting without gastrointestinal preparation (T0), before gastrointestinal endoscopy (T1), and before leaving the Post Anesthesia Care Unit (T2); and the incidences of abdominal distension during Post Anesthesia Care Unit. RESULTS: Compared with Group P, intestinal peristalsis rating was higher in Group R (P < .001); Group R showed increased motilin and gastrin levels at T2 compared with Group P (P < .01). There was a rise in motilin and gastrin levels at T1 and T2 compared with T0 and at T2 compared with T1 in both groups (P < .01). The incidence of abdominal distension was lower in Group R (P < .05). CONCLUSION: Compared with propofol used during gastrointestinal endoscopy with sedation, remimazolam tosilate mildly inhibits the serum motilin and gastrin levels, potentially facilitating the recovery of gastrointestinal motility.

Effect of Gastrin G-17 Combined with Pepsinogen PGI and PGII on the Early Screening of Gastric Cancer in the Department of Gastroenterology.

Objective: To compare serum levels of pepsinogen I (PGI), pepsinogen II (PGII), and gastrin-17 (G-17) among patients with gastritis, gastric ulcer, and gastric cancer, and to assess the effectiveness of these biomarkers individually and in combination for screening gastric cancer. Methods: Serum levels of PGI, PGII, and G-17 were measured using enzyme-linked immunosorbent assay (ELISA) in 50 patients with gastric cancer, 60 with chronic gastritis, and 60 with gastric ulcer from February 2020 to June 2021. The diagnostic value of these biomarkers was analyzed through sensitivity, specificity, and ROC curve assessments. Results: Serum PGI levels were significantly lower in patients with advanced gastric cancer compared to those with early gastric cancer (P < .05), while PGII and G-17 levels were significantly higher in advanced-stage patients (P < .05). The combined ROC curve analysis of PGI, PGII, and G-17 yielded an area under the curve (AUC) of 0.933, indicating higher diagnostic accuracy than any of the markers alone. Statistically significant differences were noted between the combined and individual tests (Z = 2.376, P < .05). Patients with PGI levels lower than 17.21 ng/ml had a worse prognosis compared to those with higher levels. Similarly, patients with PGII levels greater than 74.65 ng/ml and G-17 levels greater than 17.03 pmol/L had poorer prognoses. Additionally, higher G-17 levels were associated with significantly lower serum PGI levels. Conclusions: Patients with low expression of PGI have a poorer prognosis, and those with high expression of PGII and G-17 also have a poor prognosis. Combining the three indicators has clear value for the screening and prognostic evaluation of gastric cancer, making it worthy of clinical promotion and application.

Neglected function of gastrin to reduce feeding in Siberian sturgeon (Acipenser baerii) via cholecystokinin receptor B.

Gastrin is an important intragastrointestinal hormone, but reports on its regulation of feeding behavior in fish are still scarce. This study aimed to determine the feeding regulatory function of gastrin in sturgeon. In this study, a gastrin/cholecystokinin-like peptide was identified in the genomes of sturgeon and proved to be gastrin by evolutionary tree analysis. Tissue distribution of gastrin and its receptor, cholecystokinin receptor B (CCKRB), showed that both had high mRNA abundance in the hypothalamus and gastrointestinal tract. In the duodenum, gastrin and CCKRB mRNAs were reduced at 1 h of fasting, and both were also observed in the stomach and hypothalamus in response to changes in feeding status. Sulfated gastrin 17 is the major form of gastrin in vivo. Therefore, we investigated the effect of sulfated gastrin 17 on feeding by intraperitoneal injection into Siberian sturgeon using sulfated gastrin 17. The results showed that gastrin 17 significantly reduced the cumulative feeding of Siberian sturgeon in the short term (1, 3 and 6 h) and long term (1, 2, 3, 4, 5 and 7 days). Finally, we explored the potential mechanism of feeding inhibition after intraperitoneal injection of gastrin 17 for 7 consecutive days. The results showed that gastrin 17 treatment significantly increased the mRNA levels of anorexigenic peptides (cart, cck and pyy), while it had no significant effect on the mRNA abundance of orexigenic peptides (npy and agrp). In addition, gastrin 17 treatment significantly affected the expression of appetite signaling pathways in the hypothalamus, such that the mRNA expression of ampkα1 was significantly reduced, whereas the mRNA abundance of stat3, mtor and s6k was significantly increased. In conclusion, the present study confirmed the anorectic effect of gastrin on Siberian sturgeon.

[Therapeutic efficacy analysis of endoscopic combined with serological diagnosis strategy and endoscopic in G1 and G2 gastric neuroendocrine neoplasms].

Objective: To investigate the endoscopic combined serological diagnosis strategy for G1 and G2 gastric neuroendocrine neoplasms (G-NENs), and to evaluate the safety, short-term, and long-term efficacy of two endoscopic treatment procedures: endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). Methods: This study retrospectively analyzed the clinical data of 100 consecutive patients with G-NENs who were hospitalized at the Cancer Hospital of the Chinese Academy of Medical Sciences from January 2011 to October 2023. These patients underwent endoscopic treatment, and propensity score matching (PSM) was used to compare clinicopathological characteristics, as well as short-term and long-term efficacy of lesions in the EMR group and ESD group before and after treatment. Results: Among the 100 patients with G-NENs, the median age was 54 years old. Before surgery, 29 cases underwent endoscopic combined serological examination, and 24 of them (82.2%) had abnormally elevated plasma chromogranin A. The combined diagnostic strategy for autoimmune atrophic gastritis (AIG) achieved a diagnostic accuracy of 100%(22/22). A total of 235 G-NEN lesions were included, with 84 in the ESD group and 151 in the EMR group. The median size of the lesions in the ESD group (5.0 mm) was significantly larger than that in the EMR group (2.0 mm, P＜0.001). Additionally, the ESD group had significantly more lesions with pathological grade G2[23.8%(20/84) vs. 1.3%(2/151), P＜0.001], infiltration depth reaching the submucosal layer [78.6%(66/84) vs. 51.0%(77/151), P＜0.001], and more T2 stage compared to the EMR group[15.5%(13/84) vs. 0.7%(1/151), P＜0.001]. After PSM, 49 pairs of lesions were successfully matched between the two groups. Following PSM, there were no significant differences in the en bloc resection rate [100.0%(49/49) vs. 100.0%(49/49)], complete resection rate [93.9%(46/49) vs. 100.0%(49/49)], and complication rate [0(0/49) vs. 4.1%(2/49)] between the two groups. During the follow-up period, no recurrence or distant metastasis was observed in any of the lesions in both groups. Conclusions: The combination of endoscopy and serology diagnostic strategy has the potential to enhance the accuracy of diagnosing G1 and G2 stage G-NENs and their background mucosa. Endoscopic resection surgery (EMR, ESD) is a proven and safe treatment approach for G1 and G2 stage G-NENs.

The bHLH transcription factor ASCL1 promotes differentiation of endocrine cells in the stomach and is regulated by Notch signaling.

Notch signaling regulates gastrointestinal stem cell proliferation and differentiation yet Notch-regulated transcriptional effectors of gastric epithelial cell differentiation are poorly understood. Here we tested the role of the bHLH transcription factor Achaete-Scute homolog 1 (ASCL1) in gastric epithelial cell differentiation, and its regulation by Notch. Newborn Ascl1 null mice showed a loss of expression of markers of neurogenin-3-dependent enteroendocrine cells, with normal expression of enterochromaffin-like cells, mucous cells, chief cells, and parietal cells. In adult mice, Ascl1 gene expression was observed in the stomach, but not the intestine, with higher expression in antral than corpus epithelium. Lineage tracing in Ascl1-CreERT2; Rosa26-LSL-tdTomato mice revealed single, scattered ASCL1+ cells in the gastric epithelium, demonstrating expression in antral gastrin- and serotonin-producing endocrine cells. ASCL1-expressing endocrine cells persisted for several weeks posttamoxifen labeling with a half-life of approximately 2 months. Lineage tracing in Gastrin-CreERT2 mice demonstrated a similar lifespan for gastrin-producing cells, confirming that gastric endocrine cells are long-lived. Finally, treatment of Ascl1-CreERT2; Rosa26-LSL-tdTomato mice with the pan-Notch inhibitor dibenzazepine increased the number of lineage-labeled cells in the gastric antrum, suggesting that Notch signaling normally inhibits Ascl1 expression. Notch regulation of Ascl1 was also demonstrated in a genetic mouse model of Notch activation, as well as Notch-manipulated antral organoid cultures, thus suggesting that ASCL1 is a key downstream Notch pathway effector promoting endocrine cell differentiation in the gastric epithelium.NEW & NOTEWORTHY Although Notch signaling is known to regulate cellular differentiation in the stomach, downstream effectors are poorly described. Here we demonstrate that the bHLH transcription factor ASCL1 is expressed in endocrine cells in the stomach and is required for formation of neurogenin-3-dependent enteroendocrine cells but not enterochromaffin-like cells. We also demonstrate that Ascl1 expression is inhibited by Notch signaling, suggesting that ASCL1 is a Notch-regulated transcriptional effector directing enteroendocrine cell fate in the mouse stomach.

Nonsense mutation in the novel PERCC1 gene as a genetic cause of congenital diarrhea and enteropathy.

Congenital diarrheas and enteropathies (CODEs) constitute a heterogeneous group of individually rare disorders manifesting with infantile-onset chronic diarrhea. Genomic deletions in chromosome 16, encompassing a sequence termed the 'intestine-critical region (ICR)', were recently identified as the cause of an autosomal recessive congenital enteropathy. The regulatory sequence within the ICR is flanked by an unannotated open reading frame termed PERCC1, which plays a role in enteroendocrine cell (EEC) function. We investigated two unrelated children with idiopathic congenital diarrhea requiring home parenteral nutrition attending the Irish Intestinal Failure Program. Currently 12 and 19-years old, these Irish male patients presented with watery diarrhea and hypernatremic dehydration in infancy. Probands were phenotyped by comprehensive clinical investigations, including endoscopic biopsies and serum gastrin level measurements. Following negative exome sequencing, PCR and Sanger sequencing of the entire coding region and intron boundaries of PERCC1 were performed for each proband and their parents. In both patients, serum gastrin levels were low and failed to increase following a meal challenge. While no deletions involving the ICR were detected, targeted sequencing of the PERCC1 gene revealed a shared homozygous c.390C > G stop gain variant. We report clinical and molecular findings in two unrelated patients harboring a shared homozygous variant in PERCC1, comprising the first description of a point mutation in this gene in association with CODE. That both parenteral nutrition dependent children with unexplained diarrhea at our institution harbored a PERCC1 mutation underscores the importance of its inclusion in exome sequencing interpretation.

Novel Magnetic-Bead-Assisted Sequential Extraction Method for Liquid Chromatography-Mass Spectrometry (MS)/MS of Components with Diverse Properties: Gastrin Determination as a Case Study.

Sample preparation is the rate-limiting step in liquid chromatography-mass spectrometry (LC-MS)/MS-based clinical analysis when target analytes possess significantly different properties. Repeated solid-phase extraction (SPE) processes are typically required, resulting in low throughput and excessive consumption of labor, materials, and samples. In this study, we developed and validated a feasible and productive method to enrich target analytes with different properties during a single operation, while sufficiently removing matrix interferences to meet LC-MS/MS requirements. Gastrin determination was selected as the subject of this study. An automated magnetic-bead-assisted sequential extraction (MBASE) workflow was developed to simultaneously isolate nonsulfated gastrin-17 (G17ns), sulfated gastrin-17 (G17s), nonsulfated gastrin-34 (G34ns), and sulfated gastrin-34 (G34s) from human serum. It performs two different ion-exchange-based magnetic-bead extraction steps on one sample aliquot to produce one combined extract for LC-MS/MS analysis. When compared with the traditional SPE process, the MBASE workflow saves over 75% time and labor expenses as well as over 90% material cost, while providing even higher extraction efficiency. The MBASE LC-MS/MS method was validated as accurate and robust. Clinical sample test results demonstrated that the conventional chemiluminescence immunoassay method significantly under-estimated total gastrins in human serum, and the MBASE LC-MS/MS method could serve as an ideal tool to provide a comprehensive and accurate gastrin profile.

Update on Serum Biomarkers in Autoimmune Atrophic Gastritis.

BACKGROUND: Autoimmune atrophic gastritis (AAG) is a persistent, corpus-restricted immune-mediated destruction of the gastric corpus oxyntic mucosa with reduced gastric acid and intrinsic factor secretion, leading to iron deficiency and pernicious anemia as a consequence of iron and cobalamin malabsorption. Positivity toward parietal cell (PCA) and intrinsic factor (IFA) autoantibodies is very common. AAG may remain asymptomatic for many years, thus making its diagnosis complex and often delayed. Due to the increased risk of gastric neoplasms, a timely diagnosis of AAG is clinically important. CONTENT: The gold standard for AAG diagnosis is histopathological assessment of gastric biopsies obtained during gastroscopy, but noninvasive, preendoscopic serological screening may be useful in some clinical scenarios. Serum biomarkers for AAG may be divided into 2 groups: gastric autoimmunity-related biomarkers, such as PCA and IFA, and gastric corpus atrophy/reduced gastric acid secretion-related biomarkers, such as serum gastrin and pepsinogens. The present review focuses on the clinical significance and pitfalls of serum biomarkers related to gastric autoimmunity and gastric corpus atrophy, including some discussion of analytical methods. SUMMARY: Serum assays for PCA, IFA, gastrin, and pepsinogen I show good diagnostic accuracy for noninvasive diagnostic work-up of AAG. Diagnostic performance may increase by combining >1 of these tests, overcoming the problem of seronegative AAG. However, appropriately designed, comparative studies with well-characterized patient cohorts are needed to better define the reliability of these biomarkers in the diagnosis of patients with AAG. Currently, positive serum tests should always be followed by the state-of-art diagnostic test, that is, histopathological assessment of gastric biopsies obtained during gastroscopy to definitively confirm or rule out AAG and eventually neoplastic complications.

Development of amplified luminescent proximity homogeneous assay for quantitation of gastrin-17.

A highly sensitive and convenient amplified luminescent proximity homogeneous assay (AlphaLISA) method with high throughput and automation potential was developed for quantitation of serum Gastrin-17 (G-17) levels, which can facilitate the early diagnosis of atrophic gastritis in people at high risk of gastric cancer using a non-invasive approach. In this study, donor and acceptor beads with modified carboxyl groups on the surface were directly coupled to anti-G-17 antibodies through activation was proposed for application in the development of the new AlphaLISA, which can effectively simplify the steps and shorten the reaction time to achieve faster detection. Therefore, the G-17-AlphaLISA only needs to react for 15 min to obtain good analysis results. The proposed method has a wider detection range than commercial enzyme-linked immunosorbent assay (ELISA) kits (0.12-112.8 pmol/L > 0.5-40 pmol/L). In addition, results of G-17-AlphaLISA and ELISA had good correlation and agreement (ρ = 0.936). Importantly, the developed method may be more suitable for the large-scale screening of people at high risk for gastric cancer than traditional ELISA and provides a novel solution for other biomarkers that require accurate, highly sensitive, and high throughput detection.

Diagnostic performance of the normal range of gastrin calculated using strict criteria based on a combination of serum markers and pathological evaluation for detecting gastritis: a retrospective study.

BACKGROUND: The ABC method, which combines the pepsinogen method and anti-Helicobacter pylori antibody titers, has been used for risk screening for gastric cancer in Japan. However, it has been reported that there are cases of gastritis and carcinogenesis risk even in group A, which is considered to be a low-risk group based on the ABC method. Currently, in group A, endoscopic examination is needed to strictly discriminate "patients without gastritis" (defined as true A patients) from those "with gastritis." A simple and minimally invasive diagnostic criterion for gastritis using serological markers is desirable. In this study, we aimed to identify the normal serum gastrin concentrations in normal stomach cases based on pathological diagnosis and investigate the usefulness of serum gastrin concentrations in diagnosing gastritis. METHODS: Patients who underwent endoscopy and blood tests at Hiroshima University Hospital were enrolled in the study and categorized into the "pathologically-evaluated group" and "endoscopically-evaluated group," according to the evaluation method of atrophic gastritis. Initially, we measured serum gastrin concentrations in the normal stomach cases in the pathologically-evaluated group and calculated the normal range of serum gastrin concentrations. We used the upper limit of this normal range of serum gastrin concentrations and performed a validation study to determine its usefulness as a diagnostic marker for distinguishing between cases of gastritis and true A in the endoscopically-evaluated group. RESULTS: The 95th percentile of serum gastrin concentrations in pathologically-evaluated normal stomach cases was 34.12-126.03 pg/mL. Using the upper limit of this normal range of serum gastrin concentrations, the sensitivity, specificity, positive predictive value, and negative predictive value for gastritis were 52.8%, 92.6%, 97.0%, and 31.0%, respectively. Additionally, the receiver operating characteristic (ROC) curve for the endoscopically-evaluated group showed an area under the ROC curve of 0.80. CONCLUSION: The gastrin cut-off value of 126 pg/mL has a good positive predictive value (97.0%) for detecting gastritis positing its use as a marker for cases requiring endoscopy. However, the identification of patients with gastritis having normal serum gastrin concentrations due to insufficient sensitivity remains a challenge for the future.

Effect of GRK4 on renal gastrin receptor regulation in hypertension.

OBJECTIVE: To investigate whether GRK4 regulates the phosphorylation and function of renal CCKBR. METHODS: GRK4 A142V transgenic mice were used as an animal model of enhanced GRK4 activity, and siRNA was used to silence the GRK4 gene to investigate the regulatory effect of GRK4 on CCKBR phosphorylation and function. Finally, the co-localization and co-connection of GRK4 and CCKBR in RPT cells were observed by laser confocal microscopy and immunoprecipitation to explore the mechanism of GRK4 regulating CCKBR. RESULTS: Gastrin infusion significantly increased urinary flow and sodium excretion rates in GRK4 WT mice (P < .05). GRK4 siRNA did not affect CCKBR protein expression in WKY RPT cells and SHR RPT cells, but remarkably reduced CCKBR phosphorylation in WKY and SHR RPT cells (P < .05). The inhibitory effect of gastrin on Na+-K+ -ATPase activity in WKY RPT cells was further enhanced by the reduction of GRK4 expression (P < .05), while GRK4 siRNA restored the inhibitory effect of gastrin on Na+-K+ -ATPase activity in SHR RPT cells. Laser confocal and Co-immunoprecipitation results showed that GRK4 and CCKBR co-localized in cultured RPT cells' cytoplasm. CONCLUSION: GRK4 participates in the development of hypertension by regulating the phosphorylation of renal CCKBR leading to impaired CCKBR function and water and sodium retention. Knockdown of GRK4 restored the function of CCKBR. The enhanced co-connection between GRK4 and CCKBR may be an important reason for the hyperphosphorylation of GRK4 and CCKBR involved in the pathogenesis of hypertension.

Reversal of autoimmunity by mixed chimerism enables reactivation of ß cells and transdifferentiation of α cells in diabetic NOD mice.

Type 1 diabetes (T1D) results from the autoimmune destruction of ß cells, so cure of firmly established T1D requires both reversal of autoimmunity and restoration of ß cells. It is known that ß cell regeneration in nonautoimmune diabetic mice can come from differentiation of progenitors and/or transdifferentiation of α cells. However, the source of ß cell regeneration in autoimmune nonobese diabetic (NOD) mice remains unclear. Here, we show that, after reversal of autoimmunity by induction of haploidentical mixed chimerism, administration of gastrin plus epidermal growth factor augments ß cell regeneration and normalizes blood glucose in the firmly established diabetic NOD mice. Using transgenic NOD mice with inducible lineage-tracing markers for insulin-producing ß cells, Sox9+ ductal progenitors, Nestin+ mesenchymal stem cells, and glucagon-producing α cells, we have found that both reactivation of dysfunctional low-level insulin expression (insulinlo) ß cells and neogenesis contribute to the regeneration, with the latter predominantly coming from transdifferentiation of α cells. These results indicate that, after reversal of autoimmunity, reactivation of ß cells and transdifferentiation of α cells can provide sufficient new functional ß cells to reach euglycemia in firmly established T1D.