1
|
Aggarwal M, Cogan NG, Lewis OL. Physiological insights into electrodiffusive maintenance of gastric mucus through sensitivity analysis and simulations. J Math Biol 2021; 83:30. [PMID: 34436680 PMCID: PMC8459737 DOI: 10.1007/s00285-021-01643-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 06/24/2021] [Accepted: 07/18/2021] [Indexed: 11/28/2022]
Abstract
It is generally accepted that the gastric mucosa and adjacent mucus layer are critical in the maintenance of a pH gradient from stomach lumen to stomach wall, protecting the mucosa from the acidic environment of the lumen and preventing auto-digestion of the epithelial layer. No conclusive study has shown precisely which physical, chemical, and regulatory mechanisms are responsible for maintaining this gradient. However, experimental work and modeling efforts have suggested that concentration dependent ion-exchange at the epithelial wall, together with hydrogen ion/mucus network binding, may produce the enormous pH gradients seen in vivo. As of yet, there has been no exhaustive study of how sensitive these modeling results are with respect to variation in model parameters, nor how sensitive such a regulatory mechanism may be to variation in physical/biological parameters. In this work, we perform sensitivity analysis (using Sobol' Indices) on a previously reported model of gastric pH gradient maintenance. We quantify the sensitivity of mucosal wall pH (as a proxy for epithelial health) to variations in biologically relevant parameters and illustrate how variations in these parameters affects the distribution of the measured pH values. In all parameter regimes, we see that the rate of cation/hydrogen exchange at the epithelial wall is the dominant parameter/effect with regards to variation in mucosal pH. By careful sensitivity analysis, we also investigate two different regimes representing high and low hydrogen secretion with different physiological interpretations. By complementing mechanistic modeling and biological hypotheses testing with parametric sensitivity analysis we are able to conclude which biological processes must be tightly regulated in order to robustly maintain the pH values necessary for healthy function of the stomach.
Collapse
Affiliation(s)
| | - N G Cogan
- Florida State University, Tallahassee, USA
| | | |
Collapse
|
2
|
Le Feunteun S, Al-Razaz A, Dekker M, George E, Laroche B, van Aken G. Physiologically Based Modeling of Food Digestion and Intestinal Microbiota: State of the Art and Future Challenges. An INFOGEST Review. Annu Rev Food Sci Technol 2021; 12:149-167. [PMID: 33400557 DOI: 10.1146/annurev-food-070620-124140] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review focuses on modeling methodologies of the gastrointestinal tract during digestion that have adopted a systems-view approach and, more particularly, on physiologically based compartmental models of food digestion and host-diet-microbiota interactions. This type of modeling appears very promising for integrating the complex stream of mechanisms that must be considered and retrieving a full picture of the digestion process from mouth to colon. We may expect these approaches to become more and more accurate in the future and to serve as a useful means of understanding the physicochemical processes occurring in the gastrointestinaltract, interpreting postprandial in vivo data, making relevant predictions, and designing healthier foods. This review intends to provide a scientific and historical background of this field of research, before discussing the future challenges and potential benefits of the establishment of such a model to study and predict food digestion and absorption in humans.
Collapse
Affiliation(s)
| | - Ahmed Al-Razaz
- Essex Pathways, University of Essex, CO4 3SQ Colchester, United Kingdom;
| | - Matthijs Dekker
- Food Quality and Design Group, Department of Agrotechnology and Food Sciences, Wageningen University, 6700 AA Wageningen, The Netherlands;
| | - Erwin George
- School of Computing and Mathematical Sciences, University of Greenwich, SE10 9LS London, United Kingdom;
| | - Beatrice Laroche
- Université Paris-Saclay, INRAE, MaIAGE, 78350 Jouy-en-Josas, France;
| | - George van Aken
- Cosun Innovation Center, Royal Cosun, 4670 VA Dinteloord, The Netherlands;
| |
Collapse
|
3
|
Rajan TS, Read TL, Abdalla A, Patel BA, Macpherson JV. Ex Vivo Electrochemical pH Mapping of the Gastrointestinal Tract in the Absence and Presence of Pharmacological Agents. ACS Sens 2020; 5:2858-2865. [PMID: 32633120 DOI: 10.1021/acssensors.0c01020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ex vivo pH profiling of the upper gastrointestinal (GI) tract (of a mouse), using an electrochemical pH probe, in both the absence and presence of pharmacological agents aimed at altering acid/bicarbonate production, is reported. Three pH electrodes were first assessed for suitability using a GI tract biological mimic buffer solution containing 0.5% mucin. These include a traditional glass pH probe, an iridium oxide (IrOx)-coated electrode (both operated potentiometrically), and a quinone (Q) surface-integrated boron-doped diamond (BDD-Q) electrode (voltammetric). In mucin, the time scale for both IrOx and glass to provide a representative pH reading was in the ∼100's of s, most likely due to mucin adsorption, in contrast to 6 s with the BDD-Q electrode. Both the glass and IrOx pH electrodes were also compromised on robustness due to fragility and delamination (IrOx) issues; contact with the GI tissue was an experimental requirement. BDD-Q was deemed the most appropriate. Ten measurements were made along the GI tract, esophagus (1), stomach (5), and duodenum (4). Under buffer only conditions, the BDD-Q probe tracked the pH from neutral in the esophagus to acidic in the stomach and rising to more alkaline in the duodenum. In the presence of omeprazole, a proton pump inhibitor, the body regions of the stomach exhibited elevated pH levels. Under melatonin treatment (a bicarbonate agonist and acid inhibitor), both the body of the stomach and the duodenum showed elevated pH levels. This study demonstrates the versatility of the BDD-Q pH electrode for real-time ex vivo biological tissue measurements.
Collapse
Affiliation(s)
- Teena S. Rajan
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K
- Diamond Science and Technology CDT, University of Warwick, Coventry CV4 7AL, U.K
| | - Tania L. Read
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K
| | - Aya Abdalla
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton BN2 4AT, U.K
| | - Bhavik A. Patel
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton BN2 4AT, U.K
| | - Julie V. Macpherson
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K
| |
Collapse
|
4
|
van der Sman RGM, Houlder S, Cornet S, Janssen A. Physical chemistry of gastric digestion of proteins gels. Curr Res Food Sci 2020; 2:45-60. [PMID: 32914111 PMCID: PMC7473360 DOI: 10.1016/j.crfs.2019.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In this paper, we present the rich physics and chemistry of the gastric digestion of protein gels. Knowledge of this matter is important for the development of sustainable protein foods that are based on novel proteins sources like plant proteins or insects. Their digestibility is an important question in the design of these new protein foods. As polyelectrolyte gels, they can undergo volume changes upon shifts in pH or ionic strengths, as protein gels experience when entering the gastric environment. We show that these volume changes can be modelled using the Flory-Rehner theory, combined with Gibbs-Donnan theory accounting for the distribution of electrolytes over gel and bath. In-vitro experiments of soy protein gels in simulated gastric fluid indeed show intricate swelling behaviour, at first the gels show swelling but at longer times they shrink again. Simulations performed with the Flory-Rehner/Gibbs-Donnan theory reproduce qualitatively similar behaviour. In the final part of the paper, we discuss how the model must be extended to model realistic conditions existing in the in-vivo gastric environment.
Collapse
Affiliation(s)
- R G M van der Sman
- Wageningen Food Biobased Research, Wageningen University & Research, the Netherlands
- Food Process Engineering, Wageningen University & Research, the Netherlands
| | - Sian Houlder
- Food Process Engineering, Wageningen University & Research, the Netherlands
| | - Steven Cornet
- Wageningen Food Biobased Research, Wageningen University & Research, the Netherlands
- Food Process Engineering, Wageningen University & Research, the Netherlands
| | - Anja Janssen
- Food Process Engineering, Wageningen University & Research, the Netherlands
| |
Collapse
|
5
|
Abstract
Gastric acid secretion (i) facilitates digestion of protein as well as absorption of micronutrients and certain medications, (ii) kills ingested microorganisms, including Helicobacter pylori, and (iii) prevents bacterial overgrowth and enteric infection. The principal regulators of acid secretion are the gastric peptides gastrin and somatostatin. Gastrin, the major hormonal stimulant for acid secretion, is synthesized in pyloric mucosal G cells as a 101-amino acid precursor (preprogastrin) that is processed to yield biologically active amidated gastrin-17 and gastrin-34. The C-terminal active site of gastrin (Trp-Met-Asp-Phe-NH2 ) binds to gastrin/CCK2 receptors on parietal and, more importantly, histamine-containing enterochromaffin-like (ECL) cells, located in oxyntic mucosa, to induce acid secretion. Histamine diffuses to the neighboring parietal cells where it binds to histamine H2 -receptors coupled to hydrochloric acid secretion. Gastrin is also a trophic hormone that maintains the integrity of gastric mucosa, induces proliferation of parietal and ECL cells, and is thought to play a role in carcinogenesis. Somatostatin, present in D cells of the gastric pyloric and oxyntic mucosa, is the main inhibitor of acid secretion, particularly during the interdigestive period. Somatostatin exerts a tonic paracrine restraint on gastrin secretion from G cells, histamine secretion from ECL cells, and acid secretion from parietal cells. Removal of this restraint, for example by activation of cholinergic neurons during ingestion of food, initiates and maximizes acid secretion. Knowledge regarding the structure and function of gastrin, somatostatin, and their respective receptors is providing novel avenues to better diagnose and manage acid-peptic disorders and certain cancers. Published 2020. Compr Physiol 10:197-228, 2020.
Collapse
Affiliation(s)
- Mitchell L Schubert
- Division of Gastroenterology, Department of Medicine, Virginia Commonwealth University Health System, Richmond, Virginia, USA.,Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia, USA
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
6
|
Ni X, Tan Z, Ding C, Zhang C, Song L, Yang S, Liu M, Jia R, Zhao C, Song L, Liu W, Zhou Q, Gong T, Li X, Tai Y, Zhu W, Shi T, Wang Y, Xu J, Zhen B, Qin J. A region-resolved mucosa proteome of the human stomach. Nat Commun 2019; 10:39. [PMID: 30604760 PMCID: PMC6318339 DOI: 10.1038/s41467-018-07960-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 12/06/2018] [Indexed: 12/13/2022] Open
Abstract
The human gastric mucosa is the most active layer of the stomach wall, involved in food digestion, metabolic processes and gastric carcinogenesis. Anatomically, the human stomach is divided into seven regions, but the protein basis for cellular specialization is not well understood. Here we present a global analysis of protein profiles of 82 apparently normal mucosa samples obtained from living individuals by endoscopic stomach biopsy. We identify 6,258 high-confidence proteins and estimate the ranges of protein expression in the seven stomach regions, presenting a region-resolved proteome reference map of the near normal, human stomach. Furthermore, we measure mucosa protein profiles of tumor and tumor nearby tissues (TNT) from 58 gastric cancer patients, enabling comparisons between tumor, TNT, and normal tissue. These datasets provide a rich resource for the gastrointestinal tract research community to investigate the molecular basis for region-specific functions in mucosa physiology and pathology including gastric cancer. The human stomach is divided into seven anatomically distinct regions but their protein composition is largely unknown. Here, the authors present a region-resolved map of the healthy human stomach mucosa as well as mucosa proteomes of tumor and tumor nearby tissue from gastric cancer patients.
Collapse
Affiliation(s)
- Xiaotian Ni
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.,Center for Bioinformatics, East China Normal University, Shanghai, 200241, China
| | - Zhaoli Tan
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Chen Ding
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.,State Key Laboratory of Genetic Engineering, Human Phenome Institute, Institutes of Biomedical Sciences, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Chunchao Zhang
- Alkek Center for Molecular Discovery, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Lan Song
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.,Department of Bioinformatics, College of Life Science, Hebei University, Baoding, 071002, China
| | - Shuai Yang
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Mingwei Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Ru Jia
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Chuanhua Zhao
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Lei Song
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Wanlin Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Quan Zhou
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Tongqing Gong
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Xianju Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Yanhong Tai
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Weimin Zhu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Tieliu Shi
- Center for Bioinformatics, East China Normal University, Shanghai, 200241, China
| | - Yi Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.,Alkek Center for Molecular Discovery, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jianming Xu
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China.
| | - Bei Zhen
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.
| | - Jun Qin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China. .,State Key Laboratory of Genetic Engineering, Human Phenome Institute, Institutes of Biomedical Sciences, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, 200032, China. .,Alkek Center for Molecular Discovery, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
| |
Collapse
|
7
|
Ishizuka N, Imazeki N, Senoo A, Sakurai J, Sonoda M, Kanazawa M, Suzuki Y, Kobayashi Y, Takahashi T, Haba R, Arai K, Shimizu H, Sasaki K, Kako M, Hayashi K, Suzuki Y, Inoue S. Cell proliferation in ventromedial hypothalamic lesioned rats inhibits acute gastric mucosal lesions. Obes Res Clin Pract 2013; 6:e175-262. [PMID: 24331526 DOI: 10.1016/j.orcp.2011.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 12/20/2011] [Accepted: 12/21/2011] [Indexed: 11/26/2022]
Abstract
AIM The role of mucosal layer thickness on prevention of acute gastric mucosal lesions (AGMLs) was examined in ventromedial hypothalamic (VMH)-lesioned rats. MATERIALS AND METHODS The incidence of AGMLs after 48-h fasting and 60% ethanol injection into the stomach after 24-h fasting, aggressive factors (gastric acid and serum gastrin) and defensive factors [hexosamine, gastric mucosal blood flow (GMBF), serum thiobarbituric acid reacting substances (TBARS), and thickness of the gastric mucosal layer] were evaluated in VMH-lesioned rats. The effects of cell proliferation on the gastric mucosal layer of these rats were evaluated by H-E staining and immunostaining with proliferating cell nuclear antigen (PCNA). RESULTS After 48-h fasting, no AGMLs were observed in VMH-lesioned and sham VMH-lesioned rats (controls). With 60% ethanol administration after 24-h fasting, the numbers of AGMLs were similar in the two groups, but the ulcer index, a marker of ulcer formation, was lower in VMH-lesioned rats compared to that in sham VMH-lesioned rats. VMH-lesioned rats showed increased gastric acid secretion and serum gastrin compared to sham VMH-lesioned rats, indicating an increase in aggressive factors in VMH-lesioned rats. The two groups had similar levels of gastric mucosal hexosamine, GMBF, and gastric mucosal TBARS, but VMH-lesioned rats had an increased thickness of the mucosal cell layer, indicating an increase in defensive factors in these rats. Histologically, VMH-lesioned rats had an increased total mucosal cell layer, especially for the surface epithelial cell layer, and an increased PCNA-labeling index, a marker of cell proliferation, especially in the proliferative zones of gastric mucosa, indicating increased cell proliferation in the proliferative zone of the gastric mucosa. CONCLUSION VMH-lesioned rats are resistant to AGML formation due to increased cell proliferation in gastric mucosa through elevating the levels of defensive factors over those of aggressive factors.
Collapse
Affiliation(s)
- Noriko Ishizuka
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Nobuo Imazeki
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan.
| | - Akira Senoo
- Department of Nursing, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Junko Sakurai
- FANCL Corporation, Yokohama, Kanagawa 231-0023, Japan
| | - Masaru Sonoda
- Department of Clinical Nutrition, Faculty of Home Economics, Kyoritsu Women's University Chiyoda, Tokyo 101-8437, Japan
| | - Masao Kanazawa
- Division of Diabetology, Metabolism and Endocrinology, The Third Department of Internal Medicine, Tokyo Medical University Shinjuku, Tokyo 160-0023, Japan
| | - Yoko Suzuki
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Yoko Kobayashi
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Tosei Takahashi
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Ryota Haba
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Katsumi Arai
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Hiroyuki Shimizu
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Kahoru Sasaki
- Department of Nursing, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Masako Kako
- Department of Nursing, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Kaori Hayashi
- Department of Nursing, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| | - Yuichi Suzuki
- Department of Nutrition, Faculty of Food and Nutritional Sciences, University of Shizuoka, Shizuoka City, Shizuoka 422-8526, Japan
| | - Shuji Inoue
- Department of Nutrition, Faculty of Health Care, Kiryu University, Midori City, Gunma 379-2392, Japan
| |
Collapse
|
8
|
Zhang W, Zheng SB, Zhuang Y, Xiang P, Xiao L, Li B, Ji DN, Xia SJ, Yu Z, Shi DY. H+ /K+ ATPase expression in human parietal cells and gastric acid secretion in elderly individuals. J Dig Dis 2013; 14:366-72. [PMID: 23462150 DOI: 10.1111/1751-2980.12055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To investigate whether the ultrastructure and hydrogen potassium adenosine triphosphate (H+ /K+ ATPase) expression of human parietal cells were associated with aging. METHODS In all, 50 participants who underwent gastroscopy due to dyspepsia were divided into two age groups, with 19 in the younger group (YG, aged 20-59 years) and 31 in the elder group (EG, aged ≥60 years). The ultrastructure of their parietal cell was determined by electron microscopy (EM), and the expressions of H+ /K+ ATPase α-subunit mRNA and β-unit protein were detected. Furthermore, 24-h esophageal pH monitoring was performed in the two groups. RESULTS EM images showed no distinct difference in the morphology and distribution of parietal cells or the acid secretion-related organelle between the two groups. There were no differences between YG and EG in the proportion of mitochondria and the tubulovesicular system area. The expressions of H+ /K+ ATPase α-subunit mRNA and β-subunit protein showed no age-related alteration between YG and EG. The expression of H+ /K+ ATPase α-subunit mRNA in EG was higher than that in YG, whereas the expression of β-subunit protein was significantly higher in those aged ≥80 years than in the YG. No significant difference was found in the 24-h esophageal pH monitoring between YG and EG. CONCLUSION Acid secretion-related organelles in parietal cells do not degenerate with aging, the expression of H+ /K+ ATPase even shows a trend to increase, indicating the existence of intact molecular biological basis for acid secretion in healthy elderly individuals.
Collapse
Affiliation(s)
- Wei Zhang
- Department of Gastroenterology, Huadong Hospital affiliated to Fudan University, Shanghai, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Broide E, Bloch O, Ben-Yehudah G, Cantrell D, Shirin H, Rapoport MJ. GLP-1 receptor is expressed in human stomach mucosa: analysis of its cellular association and distribution within gastric glands. J Histochem Cytochem 2013; 61:649-58. [PMID: 23803499 DOI: 10.1369/0022155413497586] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The stomach is a target organ of the incretin hormone glucagon-like peptide-1 (GLP-1). However, the cellular expression and glandular distribution of its receptor (GLP-1R) in human gastric mucosa are not known. We determined the expression of GLP-1R in different regions of human stomach mucosa and its specific cellular association and distribution within gastric glands. Tissue samples from stomach body and antrum were obtained from 20 patients during routine esophagogastroduodenoscopy. mRNA encoding GLP-1R protein expression was evaluated by RT-PCR. Determination of cell types bearing GLP-1R, their localization, and their frequency in gastric glands in different gastric regions were estimated by immunohistochemical morphological analysis. Levels of GLP-1R mRNA were similar in body and antrum. GLP-1R immunoreactivity was found throughout the gastric mucosa in various types of glandular cells. The highest frequency of GLP-1R immunoreactive cells was found in the neck area of the principal glands in cells morphologically identified as parietal cells. GLP-1R immunostaining was also found on enteroendocrine-like cells in the pyloric glands. This study provides the first description of GLP-1R expression in human gastric glands and its specific cellular association. Our data suggest that GLP-1 may act directly on the gastric mucosa to modulate its complex functions.
Collapse
Affiliation(s)
- Efrat Broide
- Institute of Gastroenterology, Assaf Harofeh Medical Center, Zerifin, Israel
| | | | | | | | | | | |
Collapse
|
10
|
SUD DHRUV, JOSEPH IANMP, KIRSCHNER DENISE. PREDICTING EFFICACY OF PROTON PUMP INHIBITORS IN REGULATING GASTRIC ACID SECRETION. J BIOL SYST 2011. [DOI: 10.1142/s0218339004000999] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Developing drugs to treat gastric acid related illnesses such as ulcers and acid reflux disease is the leading focus of pharmaceutical companies. In fact, expenditure for treating these disorders is highest among all illnesses in the US. Over the last few decades, a class of drugs known as a proton pump inhibitors (PPIs) appeared on the market and are highly effective at abating gastric illnesses by raising stomach pH (reducing gastric acid levels). While much is known about the action of PPIs , there are still open questions regarding their efficacy, dosing and long-term effects. Here we extend a previous gastric acid secretion model developed by our group to incorporate a pharmacodynamic/pharmacokinetic model to study proton pump inhibitor (PPI) action. Model-relevant parameters for specific drugs such as omeprazole (OPZ) , lansoprazole (LPZ) and pantoprazole (PPZ) were used from published data, and we conducted simulations to study various aspects of PPI treatment. Clinical data suggests that duration of acid suppression is dependent on proton pump turnover rates and this is supported by our model. We found the order of efficacy of the different PPIs to be OPZ>PPZ>LPZ for clinically recommended dose values, and OPZ>PPZ=LPZ for equal doses. Our results indicate that a breakfast dose for once-daily dosing regimens and a breakfast-lunch dose for twice-daily dosing regimens is recommended. Simulation of other gastric disorders using our model provides atypical applications for the study of drug treatment on homeostatic systems and identification of potential side-effects.
Collapse
Affiliation(s)
- DHRUV SUD
- Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, Michigan, USA
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - IAN M. P. JOSEPH
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - DENISE KIRSCHNER
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| |
Collapse
|
11
|
van Aken GA. Relating Food Emulsion Structure and Composition to the Way It Is Processed in the Gastrointestinal Tract and Physiological Responses: What Are the Opportunities? FOOD BIOPHYS 2010. [DOI: 10.1007/s11483-010-9160-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
12
|
Abstract
Although gastric acid is not essential for life, it facilitates the digestion of protein and the absorption of iron, calcium, vitamin B(12), and thyroxin. It also prevents bacterial overgrowth and enteric infection. Gastric acid secretion must be precisely regulated, as too much acid may overwhelm mucosal defense mechanisms and lead to ulceration and maldigestion. The pathways regulating gastric acid secretion may be categorized as neural, paracrine, and hormonal; the hormonal pathways are the focus of this review. During meal ingestion, the main hormone responsible for stimulating acid secretion is gastrin, which acts primarily by releasing histamine from enterochromaffin-like cells. Ghrelin and orexin may also function as stimulatory hormones. Nutrients within the intestine, mainly lipid and protein, release peptide hormones such as cholecystokinin, secretin, neurotensin, and glucagon-like peptide, which may act in concert to inhibit acid secretion.
Collapse
Affiliation(s)
- Mitchell L Schubert
- McGuire Veterans Affairs Medical Center, Code 111N, Gastroenterology Division, 1201 Broad Rock Boulevard, Richmond, VA 23249, USA.
| |
Collapse
|
13
|
Duke-Sylvester SM, Perencevich EN, Furuno JP, Real LA, Gaff H. Advancing Epidemiological Science Through Computational Modeling: A Review with Novel Examples. ANN ZOOL FENN 2008. [DOI: 10.5735/086.045.0503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
14
|
Schubert ML, Peura DA. Control of gastric acid secretion in health and disease. Gastroenterology 2008; 134:1842-60. [PMID: 18474247 DOI: 10.1053/j.gastro.2008.05.021] [Citation(s) in RCA: 254] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 04/28/2008] [Indexed: 12/16/2022]
Abstract
Recent milestones in the understanding of gastric acid secretion and treatment of acid-peptic disorders include the (1) discovery of histamine H(2)-receptors and development of histamine H(2)-receptor antagonists, (2) identification of H(+)K(+)-ATPase as the parietal cell proton pump and development of proton pump inhibitors, and (3) identification of Helicobacter pylori as the major cause of duodenal ulcer and development of effective eradication regimens. This review emphasizes the importance and relevance of gastric acid secretion and its regulation in health and disease. We review the physiology and pathophysiology of acid secretion as well as evidence regarding its inhibition in the management of acid-related clinical conditions.
Collapse
Affiliation(s)
- Mitchell L Schubert
- Department of Medicine, Division of Gastroenterology, Virginia Commonwealth University's Medical College of Virginia, McGuire Veterans Affairs Medical Center, Richmond, Virginia 23249, USA.
| | | |
Collapse
|
15
|
An ensemble of models of the acute inflammatory response to bacterial lipopolysaccharide in rats: results from parameter space reduction. J Theor Biol 2008; 253:843-53. [PMID: 18550083 DOI: 10.1016/j.jtbi.2008.04.033] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 04/23/2008] [Accepted: 04/28/2008] [Indexed: 11/23/2022]
Abstract
In previous work, we developed an 8-state nonlinear dynamic model of the acute inflammatory response, including activated phagocytic cells, pro- and anti-inflammatory cytokines, and tissue damage, and calibrated it to data on cytokines from endotoxemic rats. In the interest of parsimony, the present work employed parametric sensitivity and local identifiability analysis to establish a core set of parameters predominantly responsible for variability in model solutions. Parameter optimization, facilitated by varying only those parameters belonging to this core set, was used to identify an ensemble of parameter vectors, each representing an acceptable local optimum in terms of fit to experimental data. Individual models within this ensemble, characterized by their different parameter values, showed similar cytokine but diverse tissue damage behavior. A cluster analysis of the ensemble of models showed the existence of a continuum of acceptable models, characterized by compensatory mechanisms and parameter changes. We calculated the direct correlations between the core set of model parameters and identified three mechanisms responsible for the conversion of the diverse damage time courses to similar cytokine behavior in these models. Given that tissue damage level could be an indicator of the likelihood of mortality, our findings suggest that similar cytokine dynamics could be associated with very different mortality outcomes, depending on the balance of certain inflammatory elements.
Collapse
|
16
|
G cells and gastrin in chronic alcohol-treated rats. Alcohol 2008; 42:37-45. [PMID: 18249268 DOI: 10.1016/j.alcohol.2007.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 08/14/2007] [Accepted: 10/09/2007] [Indexed: 12/14/2022]
Abstract
Numerous reports have described gastric mucosal injury in rats treated with high ethanol concentrations. However, to the best of our knowledge, ultrastructural characteristics of G cells and antral gastrin levels have not been previously reported, either in rats that chronically consumed alcohol or in human alcoholics. The goal of this study was to examine the effect of ethanol consumption (8.5 g/kg) over a 4-month period, under controlled nutritional conditions, on antral and plasma levels of gastrin, ultrastructure of G cells, morphometric characteristics of G cells by stereological methods, and analysis of endocrine cells in the gastric mucosa by immunohistochemistry. The chronic alcohol consumption resulted in a nonsignificant decrease in gastrin plasma levels and unchanged antral gastrin concentrations. A slightly damaged glandular portion of the gastric mucosa and dilatation of small blood vessels detected by histological analysis, suggests that ethanol has a toxic effect on the mucosal surface. Chronic alcohol treatment significantly decreased the number of antral G cells per unit area, and increased their cellular, nuclear, and cytoplasmatic profile areas. In addition, the volume density and diameter of G-cell granules, predominantly the pale and lucent types, were increased, indicating inhibition of gastrin release. Ethanol treatment also decreased the number of gastric somatostatin-, serotonin-, and histamine-immunoreactive cells, except the somatostatin cells in the pyloric mucosa, as well as both G: D: enterochromaffin cells (EC) cell ratios in the antrum and D: ECL cell ratios in the fundus. These results indicate that the change of morphometric parameters in G cells may be related to cellular dysfunction. Our findings also suggest that regulation of G-cell secretion was not mediated by locally produced somatostatin in ethanol-consuming rats, but may involve gastric luminal content and/or neurotransmitters of gastric nerve fibers.
Collapse
|
17
|
Stone SR, Giragossian C, Mierke DF, Jackson GE. Further evidence for a C-terminal structural motif in CCK2 receptor active peptide hormones. Peptides 2007; 28:2211-22. [PMID: 17950490 DOI: 10.1016/j.peptides.2007.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 09/07/2007] [Accepted: 09/10/2007] [Indexed: 11/18/2022]
Abstract
A comparison of the conformational characteristics of the related hormones [Nle(15)] gastrin-17 and [Tyr(9)-SO(3)] cholecystokinin-15, in membrane-mimetic solutions of dodecylphosphocholine micelles and water, was undertaken using NMR spectroscopy to investigate the possibility of a structural motif responsible for the two hormones common ability to stimulate the CCK(2) receptor. Distance geometry calculations and NOE-restrained molecular dynamics simulations in biphasic solvent boxes of decane and water pointed to the two peptides adopting near identical helical C-terminal configurations, which extended one residue further than their shared pentapeptide sequence of Gly-Trp-Met-Asp-Phe-NH(2). The C-terminal conformation of [Nle(15)] gastrin-17 contained a short alpha-helix spanning the Ala(11)-Trp(14) sequence and an inverse gamma-turn centered on Nle(15) while that of [Tyr(9)-SO(3)] cholecystokinin-15 contained a short 3(10) helix spanning its Met(10) to Met(13) sequence and an inverse gamma-turn centered on Asp(14). Significantly, both the C-terminal helices were found to terminate in type I beta-turns spanning the homologous Gly-Trp-Met-Asp sequences. This finding supports the hypothesis that this structural motif is a necessary condition for CCK(2) receptor activation given that both gastrin and cholecystokinin have been established to follow a membrane-associated pathway to receptor recognition and activation. Comparison of the conformations for the non-homologous C-terminal tyrosyl residues of [Nle(15)] gastrin-17 and [Tyr(9)-SO(3)] cholecystokinin-15 found that they lie on opposite faces of the conserved C-terminal helices. The positioning of this tyrosyl residue is known to be essential for CCK(1) activity and non-essential for CCK(2) activity, pointing to it as a possible differentiator in CCK(1)/CCK(2) receptor selection. The different tyrosyl orientations were retained in molecular models for the [Nle(15)] gastrin-17/CCK(2) receptor and [Tyr(9)-SO(3)] cholecystokinin-15/CCK(1) receptor complexes, highlighting the role of this residue as a likely CCK(1)/CCK(2) receptor differentiator.
Collapse
Affiliation(s)
- Shane R Stone
- Department of Chemistry, University of Cape Town, Rondebosch 7701, Cape Town, South Africa
| | | | | | | |
Collapse
|
18
|
Low MJ. Clinical endocrinology and metabolism. The somatostatin neuroendocrine system: physiology and clinical relevance in gastrointestinal and pancreatic disorders. Best Pract Res Clin Endocrinol Metab 2004; 18:607-22. [PMID: 15533778 DOI: 10.1016/j.beem.2004.08.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Somatostatin is produced in enteroendocrine D cells and intrinsic neurons of the stomach, intestines and pancreas. Its physiologic actions are mediated primarily by somatostatin receptors type 2 and 5, and include the inhibition of secretion of most endocrine and exocrine factors. Diseases directly attributable to somatostatin excess or deficiency are rare, although there is a complex pathogenic relationship between persistent Helicobacter pylori infection and reduced somatostatin in chronic gastritis. Abundant somatostatin receptors on many neoplastic and inflammatory cells are the basis for sensitive in vivo imaging with radiolabeled somatostatin analogs and provide a therapeutic target. Current indications for somatostatin therapy include hormone-expressing neuroendocrine tumors, intractable diarrhea and variceal bleeding secondary to portal hypertension. Exciting advances are being made in the development of high-affinity nonpeptide analogs with receptor-subtype selectivity and increased bioavailability. Somatostatin analogs coupled to high-energy radionuclides show promise as novel cytotoxic agents for certain metastatic tumors.
Collapse
Affiliation(s)
- Malcolm J Low
- Department of Behavioral Neuroscience, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97239, USA.
| |
Collapse
|
19
|
Abstract
PURPOSE OF REVIEW The purpose of this chapter is to summarize and place into perspective the past year's literature regarding the regulation of gastric exocrine and endocrine secretion. RECENT FINDINGS To prevent acid and pepsin from overwhelming mucosal defense mechanisms and causing injury, the secretion of gastric acid is precisely regulated by a variety of central (eg, neuropeptide Y, corticotropin-releasing factor, and neuromedin U) and peripheral (eg, gastrin, histamine, acetylcholine, somatostatin, cholecystokinin, calcitonin gene-related peptide, leptin, and parietal cell) pathways. These pathways regulate the acid-producing parietal cell directly and/or indirectly by regulating the secretion of histamine from enterochromaffin-like cells, gastrin from G cells, and somatostatin from D cells. Recently, genetically engineered mouse models have been used to reevaluate the neural, hormonal, and paracrine pathways that physiologically regulate acid secretion. SUMMARY An improved understanding of the pathways and mechanisms regulating gastric acid secretion should lead to the development of novel therapies to prevent and treat acid-peptic disorders as well as circumvent the adverse effects of currently used antisecretory medications such as the acid rebound observed after discontinuation of proton pump inhibitors.
Collapse
Affiliation(s)
- Mitchell L Schubert
- Department of Medicine, Division of Gastroenterology, Virginia Commonwealth University's Medical College of Virginia and McGuire VAMC, Richmond, Virginia, USA.
| |
Collapse
|
20
|
Joseph IM, Kirschner D. A model for the study of Helicobacter pylori interaction with human gastric acid secretion. J Theor Biol 2004; 228:55-80. [PMID: 15064083 DOI: 10.1016/j.jtbi.2003.12.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2003] [Revised: 12/05/2003] [Accepted: 12/08/2003] [Indexed: 12/21/2022]
Abstract
We present a comprehensive mathematical model describing Helicobacter pylori interaction with the human gastric acid secretion system. We use the model to explore host and bacterial conditions that allow persistent infection to develop and be maintained. Our results show that upon colonization, there is a transient period (day 1-20 post-infection) prior to the establishment of persistence. During this period, changes to host gastric physiology occur including elevations in positive effectors of acid secretion (such as gastrin and histamine). This is promoted by reduced somatostatin levels, an inhibitor of acid release. We suggest that these changes comprise compensatory mechanisms aimed at restoring acid to pre-infection levels. We also show that ammonia produced by bacteria sufficiently buffers acid promoting bacteria survival and growth.
Collapse
Affiliation(s)
- Ian M Joseph
- Department of Microbiology and Immunology, The University of Michigan Medical School, 6730 Medical Science Building II, Ann Arbor, MI 48109-0620, USA
| | | |
Collapse
|