transforming-growth-factor-alpha and Helicobacter-Infections

Growth factors and their receptors play important roles in cell proliferation, migration, tissue injury repair and ulcer healing. In gastric mucosa, transforming growth factor alpha (TGF-alpha) and epidermal growth factor (EGF) by activating their common receptor, control cell proliferation. TGF-alpha predominantly plays this role under normal conditions and after acute injury, while EGF exerts its actions mainly during healing of chronic ulcers. During regeneration of injured gastric mucosa, these growth factors serve predominantly to restore the epithelial component. Other growth factors, basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) serve to promote restoration of the connective tissue and microvessels (angiogenesis) in injured mucosa. During healing of chronic ulcers, a new epithelial lineage secreting EGF and other growth peptides develops and the majority of cells lining the ulcer margin overexpress the EGF receptor. Activation of the EGF receptor induces dramatic increases in MAP (Erk -1 and -2) kinase activity and phosphorylation levels. Inhibition of this signaling pathway dramatically delays ulcer healing. Granulation connective tissue, which grows under the stimulation of bFGF and VEGF is the major source for regeneration of connective tissue lamina propria and microvessels within the ulcer scar. Other growth factors such as insulin - like growth factor, keratinocyte growth factor, hepatocyte growth factor and trefoil peptides have been implicated in gastrointestinal (gastric ulcers, colitis) regeneration following injury. This paper is intended to provide an overview of the role of growth factors in gastrointestinal mucosal regeneration.

Topics: Animals; Cell Division; Colitis; Epidermal Growth Factor; Gastric Mucosa; Growth Substances; Helicobacter Infections; Helicobacter pylori; Humans; Intestinal Mucosa; Neovascularization, Physiologic; Regeneration; Signal Transduction; Stomach Ulcer; Transforming Growth Factor alpha; Wound Healing

Our purpose was to study the effect of Helicobacter pylori (HP) on mucosal protein fractional synthesis (MPFS) and growth factor expression. 14C-leucine incorporation, and TGF-alpha, beta-FGF, and EGF-receptor levels were assessed in gastric and duodenal mucosa in 20 patients with HP-associated gastritis and repeated after treatment of the gastritis, with or without eradication of the organism. At entry, MPFS in the fundus, antrum, and duodenum was 43.1, 38.2, and 28.3%/day, respectively. Following HP eradication, fundal and antral rates fell to 28.1 and 21.4%/day (P < 0.05), whereas the duodenum was unchanged. MPFS in the patient subset not eradicated remained similar to entry values (35.9, 31.6, and 25.4%/day). Expression of TGF-alpha, beta-FGF, and EGF receptors was unchanged. Eradication of HP results in reduction of gastric, but not duodenal, MPFS and has no effect on the growth factors measured. Increased MPFS associated with HP gastritis may relate to the potential for neoplastic transformation.

Topics: Adult; Anti-Bacterial Agents; Anti-Ulcer Agents; Chronic Disease; Duodenum; ErbB Receptors; Fibroblast Growth Factors; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Leucine; Radioactive Tracers; Transforming Growth Factor alpha

Recent studies indicate that eradication of Helicobacter pylori might prevent peptic ulcer formation in patients treated with non-steroidal anti-inflammatory drugs (NSAIDs). On the other hand, gastric adaptation after repeated exposures to aspirin (ASA) is well documented but the influence of H. pylori on this process remains to be elucidated.. To compare gastric damage and adaptation following repeated exposures to ASA in a group of patients with H. pylori infection, before and after eradication of the bacterium, and in H. pylori-negative controls.. Eight healthy volunteers without H. pylori infection and eight patients with duodenal ulcer (DU) history and H. pylori infection before and after H. pylori eradication were given ASA 2 g/day for a period of 14 days. Mucosal damage was evaluated by endoscopy and histology of biopsy samples. Gastric microbleeding, DNA synthesis in the gastric mucosa and mucosal expression, as well as luminal content of transforming growth factor-alpha (TGFalpha) were determined on days 0, 3, 7 and 14 of the ASA course.. In all patients aspirin-induced gastric damage reached a maximum on day 3. In H. pylori-positive patients, this damage was maintained at a similar level up to day 14, whereas in H. pylori-negative controls and H. pylori-eradicated patients this damage significantly lessened on day 14 and was accompanied by elevated DNA synthesis as well as increased mucosal expression and luminal release of TGFalpha.

Topics: Adaptation, Physiological; Adult; Aspirin; Cell Division; DNA; Female; Gastric Mucosa; Gastroscopy; Growth Substances; Helicobacter Infections; Helicobacter pylori; Humans; Male; Peptic Ulcer; Peptic Ulcer Hemorrhage; Transforming Growth Factor alpha

Inflammation induced by Helicobacter pylori infection related to gastric carcinogenesis. In this study, we have investigated the anti-inflammatory effect and its mechanism of kaempferol in the inflammatory response caused by H. pylori infection in vitro. We found that kaempferol reduced the expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-8) and production of IL-8 in AGS cells. In addition, kaempferol suppressed translocation of cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) of H. pylori to AGS cells. It was due to decreased transcription of type IV secretion system (T4SS) components involved in CagA injection and secretion system subunit protein A (SecA) of type V secretion system (T5SS) involved in VacA secretion by kaempferol. In conclusion, kaempferol shows the anti-inflammatory effect by suppressing the translocation of CagA and VacA proteins and leading to the down-regulation of pro-inflammatory cytokines. Abbreviations: CagA: cytotoxin-associated gene A; VacA: vacuolating cytotoxin A; T4SS: type IV secretion systems; SecA: secretion system subunit protein A; T5SS: type V secretion system.

Topics: Anti-Inflammatory Agents; Antigens, Bacterial; Bacterial Proteins; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Inflammation; Inflammation Mediators; Interleukin-1beta; Interleukin-8; Kaempferols; Protein Transport; Transforming Growth Factor alpha

Infection of gastric mucosa by H. pylori triggers a pattern of inflammatory responses characterized by the rise in proinflammatory cytokine production, up-regulation in mitogen-activated protein kinase (MAPK) cascade, and the induction in epidermal growth factor receptor (EGFR) activation. In this study, we report on the role of MAPK/p38 and Rac1 in the regulation of H. pylori LPS-induced TGF-α ectodomain shedding and EGFR transactivation. We show that stimulation of gastric mucosal cells with the LPS, reflected in p38 phosphorylation, guanine nucleotide exchange factor Dock180 activation and the rise in Rac1-GTP level, is accompanied by the activation of membrane-associated metalloprotease, (TACE) also known as ADAM17, responsible for soluble TGF-α release. Further, we reveal that the LPS-induced TGF-α shedding and EGFR transactivation involves the TACE activation through phosphorylation by p38 that requires Rac1 participation. Moreover, we demonstrate that up-regulation in H. pylori LPS-elicited Rac1-GTP membrane translocation plays a pivotal role in recruitment of the activated p38 to the membrane for TACE activation through phosphorylation on Thr(735). Taken together, our findings provide strong evidence as to the essential function of Rac1 in TACE activation, TGF-α ectodomain shedding, and the EGFR transactivation.

Topics: ADAM Proteins; ADAM17 Protein; Animals; ErbB Receptors; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Lipopolysaccharides; Mitogen-Activated Protein Kinases; p38 Mitogen-Activated Protein Kinases; Phosphorylation; rac1 GTP-Binding Protein; Rats; Transcriptional Activation; Transforming Growth Factor alpha; Up-Regulation

Ménétrier's disease (MD) is a rare, acquired, premalignant disorder of the stomach characterized by enlarged gastric folds with foveolar hyperplasia, the phenotype of antralization of gastric glands, hypochlorhydria and hypoproteinemia. The etiology of MD is unknown, but both increased signaling by transforming growth factor-α and infection with Helicobacter pylori (H. pylori) have been implicated. Here, a case involving 70-year-old man who lost weight after developing anorexia and diarrhea is reported. He was diagnosed as MD without H. pylori infection, and in spite of intensive care, he died 40 days after admission. An autopsy confirmed MD. Immunohistochemistry revealed overexpression of transforming growth factor-α in the foveolar region of the gastric mucosa. The autopsy also distinguished this H. pylori-negative MD from hyperplastic polyp of the stomach, which is important in clarifying the entity of H. pylori-negative MD.

Topics: Aged; Cyclooxygenase 2; Dilatation, Pathologic; Endosonography; Fatal Outcome; Gastric Mucosa; Gastritis, Hypertrophic; Helicobacter Infections; Helicobacter pylori; Humans; Immunohistochemistry; Insufflation; Male; Signal Transduction; Transforming Growth Factor alpha

Juvenile polyposis syndrome with gastric involvement may mimic Ménétrier's disease, which is correlated to transforming growth factor (TGF)α overproduction and PDX1 upregulation in the gastric fundus.. We report a family with juvenile polyposis syndrome where one member showed typical features of Ménétrier's disease and concomitant Helicobacter pylori infection.. We studied a 31-year-old woman belonging to a family with juvenile polyposis syndrome, who exhibited a particular form of hyperplastic gastropathy diagnosed as Ménétrier's disease with Helicobacter pylori infection.. TGFα overexpression and undetectable PDX1 expression were demonstrated in the fundic gastric biopsy specimens. In all affected members of the family we identified a 4-bp deletion in exon 9 of SMAD4 gene, a mutation usually associated with a more virulent form of juvenile polyposis syndrome with a higher incidence of gastric and colonic polyposis.. To explain the association of juvenile polyposis syndrome with Ménétrier's disease we hypothesized a new mechanism that involves TGFβ-SMAD4 pathway inactivation and TGFα overexpression related to Helicobacter pylori infection.

Topics: Adolescent; Adult; Child, Preschool; Female; Gastric Mucosa; Gastritis, Hypertrophic; Gene Expression Regulation; Helicobacter Infections; Helicobacter pylori; Homeodomain Proteins; Humans; Intestinal Polyposis; Male; Neoplastic Syndromes, Hereditary; Pedigree; Smad4 Protein; Trans-Activators; Transforming Growth Factor alpha; Transforming Growth Factor beta; Up-Regulation

Gastric secretion can provide valuable information especially when Helicobacter pylori (Hp) infection results in chronic atrophic gastritis (CAG) and intestinal metaplasia (IM) preceding adenocarcinoma (AdCa).. Looking for a potential biomarker of malignant transformation in the setting of chronic inflammation we studied the levels of prostaglandin E2 (PGE(2)), as well as peptide growth factors [epidermal growth factor (EGF) and transforming growth factor α (TGFα)], harbingers of injury and repair, in gastric juice aspirated at endoscopy from patients with CAG, CAG/IM, AdCa, and controls.. The PGE(2), EGF and TGFα concentrations in the gastric juice were measured using radioimmunoassays (RIAs).. In patients with AdCa gastric juice PGE(2) increased fivefold versus controls (P < 0.01) and almost threefold versus patients with CAG (P < 0.05). The EGF levels in patients with AdCa were fourfold higher versus controls (P < 0.001) and almost threefold higher versus CAG (P < 0.05). In patients with CAG/IM the EGF levels were also almost 3 times higher versus controls. The TGFα levels in patients with AdCa were half the value of controls and CAG (P < 0.05). In patients with CAG/IM the levels were as low as 1/5 of controls or CAG (P < 0.05).. Testing the gastric juice for PGE(2), EGF, and TGFα in patients with endoscopy and biopsy proven CAG, may be helpful in follow up of patients who may potentially progress to IM and ultimately AdCa. This could be considered as an adjunct to histologic assessment especially that even the best surveillance biopsy specimen regimens are inherited with sampling errors.

Topics: Adenocarcinoma; Adult; Aged; Biomarkers, Tumor; Digestive System Neoplasms; Dinoprostone; Epidermal Growth Factor; Female; Gastric Juice; Gastritis, Atrophic; Helicobacter Infections; Humans; Intestines; Male; Metaplasia; Middle Aged; Pilot Projects; Transforming Growth Factor alpha

To assess whether there is a correlation between the severity of gastritis and concentration of chosen growth factors in the serum of children infected with H. pylori.. The study included 64 children of whom 50% (Group I) were infected with H. pylori and had gastritis; 18.7% (Group II) of the examined children had a positive titre of IgG against H. pylori and normal gastric mucosa. Controls (Group III) comprised 31.3%. The gastric mucosa was evaluated histopathologically according to the Sydney System. The serum concentrations of growth factors: EGF, TGF-alpha, VEGF, were determined using ELISA.. Mean concentrations of the growth factors were also the highest in Group I compared to Group II and Group III (EGF - 137.3+/-10.4 pg/mL, TGF-alpha - 0.4+/-1.2 pg/mL, VEGF - 146.8 pg/mL). Analysis of correlations between growth factors and the severity of gastritis as well as the activity of antral gastric mucosa inflammation proved that mean EGF concentration in H. pylori infected children was the highest (149.5+/-84.8 pg/mL) in severe gastritis, whereas mean concentrations of TGF-alpha (2.0+/-4.3 pg/mL) and of VEGF (148.1+/-92.6 pg/mL) were the highest in moderate gastritis. Mean concentrations of EGF (155.1+/-116.4 pg/mL) and of VEGF (156.0+/-118.9 pg/mL) were the highest in high activity antral gastritis, whereas the mean concentration of TGF-alpha was the highest (2.0+/-4.2 pg/ml) in moderate activity gastritis.. In the children with H. pylori infection, serum concentrations of EGF, TGF-alpha, VEGF were the highest in moderate and severe antral gastritis.

Topics: Adolescent; Child; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Epidermal Growth Factor; Gastric Mucosa; Gastritis; Helicobacter Infections; Humans; Infant; Intercellular Signaling Peptides and Proteins; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A

Accelerated cellular proliferation in Barrett's esophagus has been implicated in Barrett's elongation and malignant transformation. Therefore, growth factors may play important roles in the pathophysiology of Barrett's esophagus. Regenerating gene (REG), an epithelial growth factor, has been reported to link mucosal inflammation and subsequent carcinogenesis in the gastrointestinal tract. The aim of this study was to investigate whether REG is expressed in Barrett's esophagus and to elucidate the relationship between REG protein expression and clinicopathological factors of Barrett's esophagus.. Between July 2003 and June 2004, 266 patients with endoscopically and histologically proven Barrett's esophagus were enrolled in this study. Before endoscopic examination, all participants were requested to answer structured questionnaires on gastroesophageal reflux symptoms and drugs usage. Mucin phenotype, cyclooxygenase-2 expression, cellular proliferation, apoptosis and REG Ialpha protein expression were investigated in the biopsy samples taken from Barrett's esophagus. Clinicopathological factors that correlated with REG Ialpha protein expression in patients with Barrett's esophagus were evaluated using multivariate logistic regression analysis.. REG Ialpha protein expression was observed in 48 (18.0%) of 266 patients with Barrett's esophagus by immunohistochemistry. Newly developed squamous re-epithelialization of Barrett's esophagus at biopsy sites, presence of hiatal hernia and aging were shown to correlate with REG Ialpha protein expression.. The present study is the first to show REG expression in Barrett's esophagus. Expression of REG Ialpha was more frequently observed in patients who showed squamous re-epithelialization of Barrett's esophagus at biopsy sites.

Topics: Aged; Aging; Barrett Esophagus; Biopsy; Esophagitis, Peptic; Female; Helicobacter Infections; Helicobacter pylori; Hernia, Hiatal; Humans; Immunohistochemistry; Lithostathine; Male; Middle Aged; Predictive Value of Tests; Transforming Growth Factor alpha; Transforming Growth Factor beta

This study, carried out on 51 patients with multifocal atrophic gastritis (MAG) and 92 age and sex-matched dyspeptic controls, was designed to examine both exocrine (gastric acid) and endocrine (gastrin) gastric secretion before and after therapeutic intervention including Helicobacter pylori eradication and vitamin C treatment.. Fasting and gastrin-releasing peptide-induced gastric acid secretion, serum levels of gastrin and proinflammatory (IL-1beta, IL-8, TNF-alpha) as well as gastric mucosal gene expression of ornithine decarboxylase (ODC), cyclooxygenase 2 (COX-2) and growth factors (epidermal growth factor and transforming growth factor alpha) were determined before and after the eradication of Helicobacter pylori and therapy with large doses (1 g/d) of vitamin C for 3 months.. The H. pylori eradication, assessed by C-urea breath test, and vitamin C therapy failed to reverse the histological atrophy of the gastric mucosa but improved significantly the functional status of the atrophied mucosa, especially its exocrine and endocrine secretory activities, attenuated the expression of premalignant markers such as ODC and COX-2, raised the production of growth factors and diminished the release of proinflammatory cytokines.. These results indicate that MAG may be considered as an environmental disease of the gastric mucosa, whose functional status can be improved by the eradication of H. pylori combined with antioxidant therapy with large doses of vitamin C.

Topics: Adult; Aged; Anti-Bacterial Agents; Antioxidants; Ascorbic Acid; Case-Control Studies; Cyclooxygenase 2; Cytokines; Epidermal Growth Factor; Female; Gastric Acid; Gastric Mucosa; Gastrins; Gastritis, Atrophic; Helicobacter Infections; Helicobacter pylori; Humans; Male; Middle Aged; Ornithine Decarboxylase; RNA, Messenger; Transforming Growth Factor alpha

Epidermal growth factor (EGF) receptor ligands (EGFRL) including transforming growth factor alpha (TGF-alpha), amphiregulin, and heparin binding-EGF (HB-EGF) are involved in gastric mucosal repair in chronic gastritis. Their mRNA expression has been shown to be upregulated after Helicobacter pylori (H.p.)-eradication but little is known about this gene expression in atrophic gastritis. The purpose of our study was to investigate EGFRL mRNA expression in gastric mucosa of patients with atrophic gastritis before and after H.p.-eradication.. Antral mucosal biopsies were obtained during endoscopy in 10 H.p. positive patients with atrophic gastritis and in 10 H.p. negative controls with intact mucosa. Total RNA of antral biopsies was extracted and RT-PCR was performed, the PCR-products being measured densitometrically. Values were compared with mRNA expressions in H.p. negative antral mucosa (n=10).. Gastric biopsies revealed mRNA expression for TGF-alpha, amphiregulin and HB-EGF, both in H.p. positive atrophic antritis and in H.p. negative healthy mucosa. The mRNA expression of TGF-alpha in atrophic gastritis was significantly upregulated after H.p.-eradication, whereas that of amphiregulin did not change after this eradication. Expression of HB-EGF mRNA was higher in H.p.-infection than after H.p.-eradication or in H.p. negative healthy subjects.. H.p. positive atrophic gastritis is associated with differential mRNA expression of EGF receptor ligands. H.p.-eradication in this entity leads to unequal changes of these growth factor expressions compared to chronic active gastritis without atrophy.

Topics: Amphiregulin; Base Sequence; DNA Primers; EGF Family of Proteins; Epidermal Growth Factor; ErbB Receptors; Gastritis, Atrophic; Glycoproteins; Growth Substances; Helicobacter Infections; Helicobacter pylori; Heparin-binding EGF-like Growth Factor; Humans; Intercellular Signaling Peptides and Proteins; Ligands; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor alpha

Epidermal growth factor (EGF) and TGF-alpha play a central role in maintaining gastric mucosal integrity. Little is known about the regulative role of the four other widely expressed epidermal growth factor receptor ligands, heparin-binding EGF, amphiregulin, betacellulin and cripto in the gastric mucosa.. Nineteen patients with Helicobacter pylori-positive gastritis and 32 healthy controls were investigated. Mucosal mRNA expression of EGF receptor ligands was determined by quantitative PCR before and after H. pylori eradication. PCR products were analyzed by soft laser scanning densitometry. Moreover, the effect of chronic active gastritis on EGF receptor expression was assessed by [125I] EGF receptor autoradiography. Immunohistochemistry was performed for TGF-alpha to localize growth factor expression.. Antral and oxyntic biopsies showed strong mRNA expressions for TGF-alpha, amphiregulin and heparin binding EGF, but not for EGF, cripto and betacellulin. mRNA expression was significantly reduced down to 50% in H. pylori infection, significantly lower compared to normal gastric mucosa, and increased after eradication therapy. Moreover, chronic gastritis was associated with decreased antral EGF receptor binding compared to healthy controls, possibly reflecting reduced autoinduction. Immunohistochemical analyses localized TGF-alpha in the cytoplasma of gastric epithelial cells and revealed its increased expression after H. pylori eradication.. The data presented suggest that amphiregulin, heparin binding EGF and TGF-alpha are important EGF receptor ligands in the gastric mucosa. H. pylori infection apparently suppresses their mRNA as well as receptor expression that is reversed by H. pylori eradication. This deficiency of the gastroprotective EGF system may contribute to the gastric pathogenicity of H. pylori infection.

Topics: Adult; Amphiregulin; Betacellulin; EGF Family of Proteins; Epidermal Growth Factor; ErbB Receptors; Female; Gastric Mucosa; Gastritis; Glycoproteins; GPI-Linked Proteins; Growth Substances; Helicobacter Infections; Helicobacter pylori; Heparin-binding EGF-like Growth Factor; Humans; Intercellular Signaling Peptides and Proteins; Male; Membrane Glycoproteins; Neoplasm Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor alpha

Gastric cancer is one of the most frequent neoplasms and a leading cause of the death world-wide. In recent years, epidemiological and animal studies demonstrated a link between gastric cancer and chronic infection with H. pylori. The exact mechanism responsible for the development of gastric cancer in H. pylori-infected patients still remains unclear. There is evidence that the up-regulation of certain growth factors could play an important role in the promotion of the gastric carcinogenesis.. The present study was designed to determine the gene expression of major known growth factors such as transforming growth factor alpha (TGFalpha), hepatocyte growth factor (HGF) and gastrin in the gastric cancer tissue, the surrounding mucosa and, for comparison, in the normal gastric mucosa. Furthermore, the luminal and plasma levels of gastrin in patients with gastric cancer were determined. In addition, the gene and protein expressions of apoptosis-related proteins such as Bax and Bcl-2 were investigated by reverse transcription-polymerase chain reaction and Western blot. Twenty-five gastric cancer patients and 40 age- and gender-matched control subjects hospitalized with non-ulcer dyspepsia were included into this study.. An overall H. pylori-seropositivity among gastric cancer patients was about 72% and was significantly higher than in the controls (56%). The prevalence of CagA-positive strains was also significantly higher among gastric cancer patients than in controls (56% vs. 32%). The gene expression of HGF and TGFalpha was detected more frequently in gastric cancer tissue samples than in normal gastric mucosa (52% vs. 12% for HGF and 48% vs. 24% for TGFalpha). The extent of protein expression in Western blotting analysis for HGF and TGFalpha correlated with the mRNA expression of these factors. Gene expression of gastrin was detected in the antrum of all tested patients and in the majority (84%) of gastric cancer patients. The median plasma and luminal concentrations of gastrin in gastric cancer patients were significantly higher than in controls. The gene expression of bcl-2 was detected in all (100%) and that of proapoptotic bax only in 56% of gastric cancer samples. In comparison to the surrounding non-tumorous tisssue, the gene expression of bax was significantly down-regulated and the gene expression of bcl-2 was up-regulated in gastric cancer tissue. At the protein level, Bax was not detectable and Bcl-2 was seen in 80% of gastric cancer samples.. It is concluded that the patients infected with H. pylori, especially with CagA-positive strains, are at a higher risk of developing a gastric cancer. An increased production and release of gastrin, as well as an over-expression of growth factors such as HGF and TGFalpha, might contribute to the gastric carcinogenesis. In addition, a dysregulation of the Bax/Bcl-2 system with significant up-regulation of Bcl-2 is observed in gastric cancer.

Topics: Adult; Aged; Apoptosis; bcl-2-Associated X Protein; Case-Control Studies; DNA, Neoplasm; Down-Regulation; Female; Gastrins; Gene Expression Regulation, Neoplastic; Helicobacter Infections; Helicobacter pylori; Hepatocyte Growth Factor; Humans; Male; Middle Aged; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Polymerase Chain Reaction; Stomach Neoplasms; Transforming Growth Factor alpha; Up-Regulation

Hypergastrinemia occurs frequently in association with acid suppression and Helicobacter infection, but its role in the progression to gastric atrophy and gastric cancer has not been well defined.. The effects of hypergastrinemia, and possible synergy with Helicobacter felis infection, were investigated in insulin-gastrin (INS-GAS) transgenic mice.. INS-GAS mice initially showed mild hypergastrinemia, increased maximal gastric acid secretion, and increased parietal cell number but later progressed to decreased parietal cell number and hypochlorhydria. Development of gastric atrophy was associated with increased expression of growth factors, heparin-binding epidermal growth factor and transforming growth factor alpha. At 20 months of age, INS-GAS mice showed no evidence of increased enterochromaffin-like cell number, but instead exhibited gastric metaplasia, dysplasia, carcinoma in situ, and gastric cancer with vascular invasion. Invasive gastric carcinoma was observed in 6 of 8 INS-GAS mice that were >20 months old. Helicobacter felis infection of INS-GAS mice led to accelerated (< or = 8 mo) development of intramucosal carcinoma (85%), with submucosal invasion (54%) and intravascular invasion (46%; P < or = 0.05).. These findings support the unexpected conclusion that chronic hypergastrinemia in mice can synergize with Helicobacter infection and contribute to eventual parietal cell loss and progression to gastric cancer.

Topics: Animals; Cell Count; Epidermal Growth Factor; Epithelial Cells; Gastric Acid; Gastrins; Gastritis, Atrophic; Helicobacter Infections; Heparin; Heparin-binding EGF-like Growth Factor; Hyperplasia; Hypertrophy; Intercellular Signaling Peptides and Proteins; Metaplasia; Mice; Mice, Transgenic; Stomach Neoplasms; Transforming Growth Factor alpha

We studied the expression of cell cycle regulators and growth factor-receptor systems in gastric carcinoma in young adults and tried to clarify the specific alterations associated with H. pylori. We studied 33 young patients (18-29 years old, mean age 26.4) with gastric carcinoma. The patients were classified into two groups according to the degree of atrophic gastritis. Then we examined the expression of p53, cripto, cyclin-E, c-met, c-erbB2 and TGF-alpha immunohistochemically and compared the results between the two groups. The results were compared with 66 sex-, tumor histology-, and depth-matched elder controls (36-86 years old, mean age 64.0). H. pylori was judged by Giemsa staining. Seventeen patients had atrophic changes in the corpus (Group A), while 16 showed superficial gastritis or normal mucosa (Group S). All 17 patients of Group A showed H. pylori infection, while the 3 of the 16 members of Group S did not have H. pylori. p53 overexpression was observed more frequently in Group S (88%) than in Group A (41%, p<0.05). In the 3 patients without H. pylori infection, all carcinoma specimens showed p53 overexpression. Overexpression of cyclin-E was detected in 4 patients from Group S. On the other hand, cripto was observed more frequently in Group A than in Group S. No obvious differences were observed in c-erbB2, TGF-alpha and c-met expression. Overall, p53 overexpression was detected more frequently in younger than in older patients, whereas cripto expression was less detected. These results suggest that p53 and cyclin-E may act in an H. pylori-independent or -adjunctive manner for gastric carcinogenesis. Cripto expression might be correlated tightly with H. pylori infection.

Topics: Adolescent; Adult; Cell Cycle Proteins; Cyclin E; Epidermal Growth Factor; Female; GPI-Linked Proteins; Growth Substances; Helicobacter Infections; Humans; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Male; Membrane Glycoproteins; Neoplasm Proteins; Proto-Oncogene Proteins c-met; Receptor, ErbB-2; Receptors, Growth Factor; Stomach Neoplasms; Transforming Growth Factor alpha; Tumor Suppressor Protein p53

Various growth factors were also reported to promote healing of peptic ulcer. We have used a monoclonal antibody in conjunction with a standard immunohistochemical technique to characterize the expression of transforming growth factor-alpha (TGF-alpha) in duodenal ulcer. TGF-alpha immunoreactivity is found in Brunner's gland, also in immature gland and in duodenal epitheliums, but not in gastric metaplasia of the duodenum. TGF-alpha expression of healing and scar stage was higher than that of active stage. The presence or absence of Helicobacter pylori infection did not affect the expression of TGF-alpha in duodenal ulcer.

Topics: Adult; Aged; Aged, 80 and over; Duodenal Ulcer; Helicobacter Infections; Helicobacter pylori; Humans; Immunohistochemistry; Middle Aged; Transforming Growth Factor alpha

Involvement of Helicobacter pylori in aspirin-induced gastropathy and adaptation to aspirin remains unclear. The aim of this study was to compare gastric damage and adaptation after repeated exposures to acetylsalicylic acid in the same subjects before and after eradication of H. pylori.. Before and after H. pylori eradication, 8 volunteers were given aspirin, 2 g/day during 14 days. Mucosal damage was evaluated by endoscopy and histological analysis of biopsy samples. Gastric microbleeding, DNA synthesis, prostaglandin E2 generation, and luminal contents of transforming growth factor alpha and its immunohistochemical expression were determined on days 0, 3, 7, and 14 of aspirin course.. In all subjects, aspirin-induced gastric damage that reached maximum on day 3. In H. pylori-positive subjects, this damage was maintained at a similar level up to day 14. After H. pylori eradication, the damage was significantly lessened both in endoscopy and histology at day 14 and accompanied by increased mucosal expression and luminal release of transforming growth factor alpha. Prostaglandin E2 generation was significantly greater in H. pylori-positive subjects than after H. pylori eradication, but aspirin treatment resulted in >90% reduction of this generation independent of H. pylori status.. Gastric adaptation to aspirin is impaired in H. pylori-positive subjects, but eradication of this bacterium restores this process.

Topics: Adaptation, Physiological; Adolescent; Adult; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Dinoprostone; DNA; Female; Gastric Mucosa; Gastrointestinal Hemorrhage; Helicobacter Infections; Helicobacter pylori; Humans; Male; Regional Blood Flow; RNA; Transforming Growth Factor alpha

Epidermal growth (EGF) and transforming growth factor alpha (TGFalpha) are potent gastric secretory inhibitors, mitogens, and mucosal protectors, but the impact of Helicobacter pylori infection on their mucosal expression and luminal release has not been clarified.. In this study, gene and immunoreactive and immunohistochemical expressions of EGF and TGFalpha were assessed in the gastric mucosa of 15 H. pylori-negative healthy normals, in 22 H. pylori-positive duodenal ulcer patients (DU) and in 24 H. pylori-positive non-ulcer dyspepsia patients (NUD). All studies in DU and NUD patients were repeated after 2 weeks of triple therapy (amoxicillin + clarithromycin + omeprazole) and 4 weeks and 2 years later.. Immunohistochemical expression of EGF and TGFalpha in H. pylori-positive DU and NUD was significantly higher than in H. pylori-negative normals, and this increase persisted at 2 and 4 weeks after therapy but normalized 2 years later. EGF mRNA was detected in the gastric mucosa of H. pylori-positive DU before and at 2 and 4 weeks after H. pylori eradication, but it was not found 2 years after the eradication of H. pylori or in gastric mucosa of H. pylori-negative control subjects. TGFalpha mRNA was detected in the gastric mucosa independently of H. pylori status, with the stronger expression observed in the gastric mucosa of H. pylori-positive DU and NUD before eradication than after this procedure. Plasma gastrin, which was significantly increased in H. pylori-positive DU, normalized already after 2 weeks of triple therapy. The eradication rate as determined by histology after triple therapy reached 86.3% in DU patients and 90.5% in NUD patients. Two years after the eradication the H. pylori reinfection rate was 4.5% among DU patients and 4.2% among NUD. Treatment of DU patients with triple therapy resulted in complete ulcer healing.. 1) Chronic H. pylori infection and resulting antral gastritis are associated with increased plasma gastrin and increased mucosal cell proliferation, probably due to enhanced expression of EGF and TGFalpha, and 2) the H. pylori eradication results in a decrease in plasma gastrin, but the increase in gastric TGFalpha and EGF content is sustained, suggesting that they may be involved in ulcer healing.

Topics: Adult; Cell Division; Duodenal Ulcer; Dyspepsia; Epidermal Growth Factor; Female; Gastric Mucosa; Gastrins; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Immunohistochemistry; Male; Middle Aged; Polymerase Chain Reaction; Proliferating Cell Nuclear Antigen; Radioimmunoassay; Transforming Growth Factor alpha

Acute exposure to Helicobacter pylori causes cell damage and impairs the processes of cell migration and proliferation in cultured gastric mucosal cells in vitro. EGF-related growth factors play a major role in protecting gastric mucosa against injury, and are involved in the process of gastric mucosal healing. We therefore studied the acute effect of H. pylori on expression of EGF-related growth factors and the proliferative response to these factors in gastric mucosal cells (MKN 28) derived from gastric adenocarcinoma. Exposure of MKN 28 cells to H. pylori suspensions or broth culture filtrates upregulated mRNA expression of amphiregulin (AR) and heparin-binding EGF-like growth factor (HB-EGF), but not TGFalpha. This effect was specifically related to H. pylori since it was not observed with E. coli, and was independent of VacA, CagA, PicA, PicB, or ammonia. Moreover, H. pylori broth culture filtrates stimulated extracellular release of AR and HB-EGF protein by MKN 28 cells. AR and HB-EGF dose-dependently and significantly stimulated proliferation of MKN 28 cells in the absence of H. pylori filtrate, but had no effect in the presence of H. pylori broth culture filtrates. Inhibition of AR- or HB-EGF- induced stimulation of cell growth was not mediated by downregulation of the EGF receptor since EGF receptor protein levels, EGF binding affinity, number of specific binding sites for EGF, or HB-EGF- or AR-dependent tyrosine phosphorylation of the EGF receptor were not significantly altered by incubation with H. pylori broth culture filtrates. Increased expression of AR and HB-EGF were mediated by an H. pylori factor > 12 kD in size, whereas antiproliferative effects were mediated by both VacA and a factor < 12 kD in size. We conclude that H. pylori increases mucosal generation of EGF-related peptides, but in this acute experimental model, this event is not able to counteract the inhibitory effect of H. pylori on cell growth. The inhibitory effect of H. pylori on the reparative events mediated by EGF-related growth factors might play a role in the pathogenesis of H. pylori-induced gastroduodenal injury.

Topics: Adenocarcinoma; Amphiregulin; Cell Division; Cell Line; EGF Family of Proteins; Epidermal Growth Factor; ErbB Receptors; Gastric Mucosa; Gastritis; Glycoproteins; Growth Substances; Helicobacter Infections; Helicobacter pylori; Heparin; Heparin-binding EGF-like Growth Factor; Humans; Intercellular Signaling Peptides and Proteins; Peptic Ulcer; Recombinant Proteins; RNA, Messenger; Stomach Neoplasms; Transforming Growth Factor alpha; Up-Regulation; Virulence

The relationship between the expression of epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) and that of their receptor (EGF-R) in the Helicobacter pylori-infected gastric mucosa has not been completely elucidated. The aim of this study was to examine the interplay between H. pylori colonization and gastric mucosal growth factor content.. By means of a solid-phase enzyme-linked immunosorbent assay EGF, TGF-alpha, and EGF-R levels and interleukin-1beta (IL-1beta) content, which is considered a marker of chronic inflammation, were evaluated in the antral mucosa of 24 H. pylori-positive patients before and 8 weeks after eradication therapy.. After therapy H. pylori was eradicated in 19 patients. The eradication was accompanied by a significant decrease in IL-1beta content and an increase in EGF and TGF-alpha levels. On the other hand, in the five patients in whom the bacterium was not eradicated EGF, TGF-alpha, and EGF-R levels were quite similar to those assayed before therapy, whereas IL-1beta content was still high.. These results suggest that H. pylori exerts an inhibitory effect on the mucosal expression of EGF and TGF-alpha, which are likely involved in the gastric mucosa repair process.

Topics: Adult; Anti-Bacterial Agents; Anti-Ulcer Agents; Dyspepsia; Epidermal Growth Factor; ErbB Receptors; Female; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Humans; Interleukin-1; Male; Middle Aged; Transforming Growth Factor alpha

Helicobacter hepaticus is a new bacterial species that is homologous to Helicobacter pylori, a human gastric carcinogen. H. hepaticus causes chronic active hepatitis, with progression to hepatocellular tumors. We hypothesized that chronic up-regulation of epidermal growth factor (EGF), transforming growth factor-alpha, and nuclear oncogenes (cyclin D1 and c-Myc), all known to transform by overexpression, might contribute to tumorigenesis. Livers from mice that were 6-18 months old were analyzed, including nonneoplastic and preneoplastic tissues and tumors, along with age-matched controls, by immunohistochemistry and immunoblotting. EGF and transforming growth factor-alpha were increased at the earliest stage, with a further increase in EGF in tumors. Cyclin D1, cyclin-dependent kinase 4, and c-Myc were strongly increased in all infected livers, with even greater increases in tumors. An increase in cyclin D1/cyclin-dependent kinase 4 complex was also demonstrated in tumors, and its functionality was confirmed by an increase in the hyperphosphorylated:hypophosphorylated retinoblastoma protein ratio. Our findings suggest a possible cooperation of growth factors, cell cycle proteins, and transcription factors during the development of H. hepaticus-associated liver tumors and may have relevance to human cancers associated with bacterial, viral, or parasitic infections.

Topics: Animals; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinases; Epidermal Growth Factor; Helicobacter Infections; Hepatitis, Animal; Liver Neoplasms, Experimental; Male; Mice; Mice, Inbred A; Neoplasm Proteins; Phosphorylation; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-myc; Retinoblastoma Protein; Transforming Growth Factor alpha

Topics: Adult; Duodenum; Dyspepsia; Female; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Humans; Intestinal Mucosa; Male; Middle Aged; Osmolar Concentration; Transforming Growth Factor alpha

Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF alpha) are potent gastric acid inhibitors and stimuli of mucosal growth and protection but their involvement in Helicobacter pylori associated duodenal ulcer has been little examined.. To assess gastric acid secretion, plasma gastrin concentrations, mucosal content of EGF and TGF alpha, and mucosal expression of these peptides and their receptor (EGFr) as well as salivary and gastric luminal release of EGF under basal conditions and after pentagastrin stimulation in 10 healthy subjects and in 25 H pylori positive patients with duodenal ulcer before and after two weeks of triple anti-H pylori therapy and four weeks after the termination of this therapy.. Pentagastrin stimulation caused a significant increase in salivary and gastric release of EGF both in healthy controls and patients with duodenal ulcers but in the patients, the eradication of H pylori resulted in several fold higher gastric luminal (but not salivary) EGF release than before the anti-H pylori therapy. Mucosal contents of immunoreactive EGF and TGF alpha and mucosal expression of EGF, TGF alpha, and EGFr in H pylori positive patients with duodenal ulcer were significantly higher than those in healthy H pylori negative controls and this increase persisted after eradication of H pylori. Basal plasma gastrin was significantly reduced after two weeks of triple therapy and four weeks after the H pylori eradication all ulcers were completely healed.. (1) H pylori infection in patients with duodenal ulcer was accompanied by enhanced plasma gastrin and increased mucosal content and expression of TGF alpha, EGF, and EGFr; (2) H pylori eradication resulted in ulcer healing, reduction in plasma gastrin, and enhancement of gastric (but not salivary) luminal release of EGF, particularly after pentagastrin stimulation; and (3) enhanced mucosal content and expression of TGF alpha, EGF, and EGFr and increased luminal release of EGF may contribute to ulcer healing after eradication of H pylori.

Topics: Duodenal Ulcer; Epidermal Growth Factor; ErbB Receptors; Follow-Up Studies; Gastric Mucosa; Gastrins; Helicobacter Infections; Helicobacter pylori; Humans; Pentagastrin; Saliva; Transforming Growth Factor alpha

Previous study showed that duodenal ulcer (DU) patients infected with Helicobacter pylori (H. pylori) have increased basal and pentagastrin- or GRP-induced gastric acid secretion and that these disturbances reversed fully after eradication of H. pylori. This study was designed to compare the gastric acid secretory profile, plasma gastrin levels and growth factors (EGF and TGF alpha) expression in gastric mucosa in DU patients with those in atrophic gastritis patients before and six months after verified eradication of H. pylori. In DU patients, basal and stimulated (GRP and pentagastrin) gastric acid secretion was significantly higher than in healthy controls. Six months following the eradication of H. pylori with triple therapy (omeprazole+clarithromycin+amoxicillin), this secretion returned to normal value. In contrast, in patients with atrophic gastritis, such eradication of H. pylori resulted in a significant increase in basal and pentagastrin- and GRP-stimulated acid secretion. Mucosal expression of immunoreactive EGF and TGF alpha was significantly enhanced in H. pylori positive DU and atrophic gastritis patients but this elevation disappeared or was markedly decreased 6 months upon the eradication of H. pylori. We conclude that 1) H. pylori infection is accompanied both in DU and atrophic gastritis patients by an enhanced plasma gastrin and increased mucosal expression of EGF and TGF alpha, 2) basal and GRP-induced acid secretion is significantly elevated in DU, whereas that in atrophic gastritis patients is greatly reduced, and 3) the H. pylori eradication restores gastric acid and plasma gastrin release as well as the mucosal expression of growth factors in DU and atrophic gastritis.

Topics: Adult; Duodenal Ulcer; Epidermal Growth Factor; Gastric Acid; Gastric Mucosa; Gastrin-Releasing Peptide; Gastrins; Gastritis, Atrophic; Helicobacter Infections; Helicobacter pylori; Humans; Immunohistochemistry; Male; Transforming Growth Factor alpha

Epidemiological studies have consistently shown an association between infection of Helicobacter pylori (Hp) and duodenal ulcer (DU) and gastric cancer. The mechanism of the ulcerogenic effect of Hp has been related to excessive gastrin release, gastric acid hypersecretion and gastric metaplasia in duodenum. The implication of Hp in gastric carcinogenesis has not been explained. In this study, mucosal expression of EGF and TGF alpha and luminal release of EGF as well as basal and pentagastrin-stimulated acid secretion and plasma gastrin levels have been determined in healthy subjects, gastric carcinoma and DU patients. It was found that Hp positive DU patients show excessive gastrin release and gastric acid secretion combined with increased expression and luminal release of EGF and TGF alpha. These changes returned to normal values two years after the eradication of Hp. Gastric cancer patients also showed increased expression of EGF and TGF alpha and highly increased plasma gastrin but their gastric acid secretion was markedly reduced possibly due to atrophy of oxyntic mucosa. This study indicates that overexpression of growth factors in gastric mucosa may be implicated in the pathogenesis of both duodenal ulcer and gastric cancer and that Hp positive hypochlorhydric and hypergastrinemic patients may be predisposed to development of gastric cancer.

Topics: Adult; Aged; Carcinoma; Duodenal Ulcer; Epidermal Growth Factor; Gastric Acid; Gastric Juice; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Humans; Immunochemistry; Middle Aged; Pentagastrin; Stomach Neoplasms; Transforming Growth Factor alpha

Epidermal growth factor (EGF), pivotal in mucosal protection, is partly degraded proteolytically at low pH in the gastric milieu; gastric acid secretion, on the other hand, remains influenced by H. pylori colonization. The aim of this study, therefore, was to evaluate the impact of low pH and H. pylori colonization status on immunoreactive EGF and the other member of EGF-family, immunoreactive transforming growth factor-alpha (TGF-alpha). Eighteen patients with nonulcer dyspepsia (NUD) colonized by H. pylori and 55 NUD patients without H. pylori colonization were investigated. Gastric juice samples were aspirated at the beginning of the endoscopy procedure and immediately placed on ice, and their pH was recorded. The measurement of immunoreactive EGF and TGF-alpha was performed using commercially available radioimmunoassays (RIAs) after adjustment of pH to neutral using an assay buffer. Statistical analysis was performed using sigma-Stat for Windows. The concentration of immunoreactive EGF in patients with NUD colonized by H. pylori was 80% lower (P < 0.02) than in those without H. pylori and in both groups immunoreactive EGF was significantly lower when the pH of gastric juice was below 4.0. The concentration of immunoreactive EGF in H. pylori(+) and H. pylori(-) patients was similar when the pH of aspirated gastric juice was above 4.0. However, with gastric juice pH < 4.0, the EGF concentration was 64% lower in H. pylori(+) patients than H. pylori(-) patients (P < 0.05). In general, the concentration of immunoreactive TGF-alpha in gastric juice was unaffected by H. pylori colonization or pH of gastric juice. It is concluded that: (1) significantly lower immunoreactive EGF concentrations in patients with pH below 4.0 indicate that immunoreactive EGF but not immunoreactive TGF-alpha is affected by an acidic gastric milieu; (2) the further reduction of gastric juice immunoreactive EGF at pH below 4.0 in patients colonized by H. pylori suggests that this microorganism may elaborate factors that accelerate its proteolytic degradation or inhibit its rate of synthesis and/or secretion; and (3) this diminished content of immunoreactive EGF at low pH, especially in patients colonized by H. pylori, may facilitate the development and/or progression of mucosal damage.

Topics: Adult; Aged; Aged, 80 and over; Analysis of Variance; Epidermal Growth Factor; Female; Gastric Acidity Determination; Gastric Juice; Gastroscopy; Helicobacter Infections; Helicobacter pylori; Humans; Male; Middle Aged; Transforming Growth Factor alpha

It has been reported that eradication of Helicobacter pylori improves fold width in H pylori associated enlarged fold gastritis. The aim of this study was to clarify the mechanism of fold thickening in this condition.. In eight patients with enlarged fold gastritis and 13 patients without enlarged folds, the presence of H pylori infection, inflammatory infiltrates, mucosal plasia, and epithelial cell proliferation in the body mucosa were investigated, and production of transforming growth factor alpha (TGF alpha), hepatocyte growth factor (HGF), and interleukin 1 beta (IL 1 beta) was determined by a competitive reverse transcription/polymerase chain reaction method and in vitro short-term culture of biopsy specimens.. In the patients with enlarged fold gastritis, inflammatory infiltrates including macrophages increased with H pylori colonisation in the body. Foveolar thickness and proliferating cell nuclear antigen (PCNA) labelling index were increased. Messenger RNA levels of HGF, but not TGF alpha, were increased, and release of HGF and IL 1 beta was increased. HGF release, which was positively correlated with IL 1 beta release and foveolar thickness, decreased in the presence of IL 1 receptor antagonist. After eradication of H pylori, inflammatory infiltrates, IL 1 beta and HGF release decreased with concomitant decreases in PCNA labelling index, foveolar thickness and fold width.. Increased IL 1 beta and HGF production caused by H pylori infection may contribute to fold thickening of the stomach by stimulating epithelial cell proliferation and foveolar hyperplasia in patients with enlarged fold gastritis.

Topics: Adult; Aged; Biomarkers; Epithelium; Female; Gastric Mucosa; Gastritis, Hypertrophic; Helicobacter Infections; Helicobacter pylori; Hepatocyte Growth Factor; Humans; Interleukin-1; Male; Middle Aged; Polymerase Chain Reaction; Proliferating Cell Nuclear Antigen; RNA, Messenger; Transforming Growth Factor alpha