8-hydroxy-2--deoxyguanosine and Gastritis

The aim of this study was to test the effect of antioxidant supplementation on enzymatic abnormalities and free radical-modified DNA adducts associated with premalignant changes in the gastric mucosa of elderly patients with HP-negative atrophic gastritis (CAG). Sixty patients with atrophic gastritis and intestinal metaplasia underwent a nutritional interview and a gastroscopy with multiple biopsy samples in the antrum that were processed for histology and for assaying: alpha-tocopherol, MDA, xanthine oxidase (XO), ornithine decarboxylase (ODC), and 8-OHdG. Patients were randomly allocated into three matched groups and supplemented for 6 months with (1) vitamin E, 300 mg/day; (2) multivitamin, two tablets t.i.d.; and (3) Immun-Age 6 g/day nocte (ORI, Gifu, Japan), a certified fermented papaya preparation with basic science-validated antioxidant/immunomodulant properties. Ten dyspeptic patients served as controls. Histology and biochemistry were blindly repeated at 3 and 6 months. CAG patients showed a significantly (P <.05) increased level of mucosal MDA and XO concentration that were reverted to normal by each supplementation (P <.05). All supplements caused a significant decrease of ODC (P <.01), but Immun-Age yielded the most effective (P < 0.05) and was the only one significantly decreasing 8-OhdG (P < 0.05). These data suggest that antioxidant supplementation, and, namely, Immun-Age, might be potential chemopreventive agents in HP-eradicated CAG patients and especially in the elderly population.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aging; Antioxidants; Deoxyguanosine; Dietary Supplements; DNA; DNA Adducts; Gastric Mucosa; Gastritis; Gastritis, Atrophic; Gene Expression Regulation; Humans; Models, Biological; Mucous Membrane; Oxidants; Oxidative Stress; Pilot Projects; Precancerous Conditions; Random Allocation; Reverse Transcriptase Polymerase Chain Reaction; Stomach Neoplasms; Up-Regulation; Vitamin E; Vitamins; Xanthine Oxidase

Helicobacter pylori (H.pylori) is associated with chronic gastritis, peptic ulcers, gastric adenocarcinomas and mucosa associated tissue lymphomas. Cytotoxin associated gene A (CagA) is one of the virulence factors of H.pylori. It is hypothesized that reactive oxygen species (ROS) play roles in H.pylori associated disease especially in development of gastric adenocarcinoma. Individuals infected with H.pylori bearing CagA produce more ROS than others. 8-hydroxydeoxyguanosine (8OHdG) is an in vitro marker of DNA damage and oxidative stress. The aim of this study was to investigate the relationship between 8OHdG level, H.pylori infection and CagA and alterations of serum 8OHdG level after H.pylori eradication.. Patients admitted with dyspeptic complaints and upper gastrointestinal endoscopy were assessed. H.pylori was determined from histopathology of specimens. Serum 8OHdG levels of three groups (H.pylori negative, H. pylori positive CagA negative and H.pylori positive CagA positive) were compared. Patients with H.pylori infection received eradication therapy. Serum 8OHdG levels pretreatment and posttreatment were also compared.. In total, 129 patients (M/F, 57/72) were enrolled in the study. Serum 8OHdG level of H.pylori negative, H. pylori positive CagA negative and H.pylori positive CagA positive groups were significantly different (5.77±1.35 ng/ml, 5.43±1.14 ng/ml and 7.57±1.25 ng/ml respectively, p=0.05). Furthermore, eradication therapy reduced serum 8OHdG level (6.10±1.54 ng/ml vs 5.55±1.23 ng/ml, p=0.05).. Individuals infected with H.pylori bearing CagA strains have the highest serum 8OHdG level and eradication therapy decreases the serum 8OHdG level. To the best of our knowledge this is the first study that evaluated the effect of CagA virulence factor on serum 8OHdG level and the effect of eradication therapy on serum 8OHdG levels together. Eradication of CagA bearing H.pylori may prevent gastric adenocarcinoma by decreasing ROS. 8OHdG level may thus be a good marker for prevention from gastric adenocarcinoma.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adolescent; Adult; Aged; Antigens, Bacterial; Bacterial Proteins; Biomarkers; Deoxyguanosine; Female; Follow-Up Studies; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Male; Middle Aged; Neoplasm Staging; Peptic Ulcer; Prognosis; Young Adult

Helicobacter pylori infection is an established risk factor for gastritis, gastric ulcer, peptic ulcer and gastric cancer. CagA +ve H. pylori has been associated with oxidative DNA damage of gastric mucosa but their combined role in the development of gastric cancer is still unknown. Here we compare the combined expression of cagA and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in normal, gastritis and gastric cancer tissues. Two hundred gastric biopsies from patients with dyspeptic symptoms, 70 gastric cancer tissue samples and 30 gastric biopsies from non-dyspeptic individuals (controls) were included in this study and 8-OHdG was detected by immunohistochemistry (IHC). Histological features and the presence of H. pylori infection were demonstrated by Hematoxylin and Eosin (HE), Giemsa and alcian blue-periodic acid-Schiff ± diastase (AB-PAS ± D) staining. DNA was extracted from tissues and polymerase chain reaction (PCR) performed to determine the presence of ureaseA and cagA genes of H. pylori. The results showed the presence of H. pylori in 106 (53 %) gastric biopsies out of 200 dyspeptic patients, including 70 (66 %) cases of cagA + ve H. pylori. The presence of cagA gene and high expression of 8-OHdG was highly correlated with severe gastric inflammation and gastric cancer particularly, in cases with infiltration of chronic inflammatory cells (36.8 % cagA + ve, 18 %), neutrophilic activity (47.2 %, 25.5 %), intestinal metaplasia (77.7 %, 35.7 %) and intestinal type gastric cancer (95 %, 95.4 %) (p ≤ 0.01). In conclusion, H. Pylori cagA gene expression and the detection of 8-OHdG adducts in gastric epithelium can serve as potential early biomarkers of H. Pylori-associated gastric carcinogenesis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Biomarkers; Cell Transformation, Neoplastic; Deoxyguanosine; DNA Damage; Female; Follow-Up Studies; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Immunoenzyme Techniques; Male; Middle Aged; Neoplasm Staging; Oxidative Stress; Polymerase Chain Reaction; Prognosis; Stomach Neoplasms

To investigate the relationship between oxidative stress and gastric carcinogenesis of poorly differentiated adenocarcinoma in young patients, we analyzed the surgically resected specimens of 22 young patients (21-30 years) and 29 older patients (41-72 years) with intramucosal gastric cancer of the poorly differentiated type. We used immunohistochemical staining to evaluate the expression of 8-hydroxydeoxyguanosine (8OHdG), induced nitric oxide synthetase (iNOS), and antioxidant enzymes (thioredoxin [TRX] and peroxiredoxin [PRDX1, 2 and 3]). We assessed these proteins in the cancer, noncancerous gastric foveolar epithelium and noncancerous mucosal neck. In both the young and older patient groups, the 8OHdG and TRX expressions were gradually increased in cancer cells compared with the noncancerous foveolar epithelial cells and the noncancerous mucosal neck cells (P < 0.001). Although the iNOS and PRDXs expressions were increased in the noncancerous mucosal neck cells compared with the noncancerous foveolar epithelial cells, regardless of age (P < 0.001), the iNOS and PRDX2 expression in the cancer cells were significantly reduced in the young patients compared with the older patients (P < 0.001, P < 0.05). In conclusion, the reduced expression of iNOS or PRDX2 may play an important role in the carcinogenesis of gastric cancer associated with Helicobacter pylori-induced chronic active gastritis in young patients.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Age Distribution; Aged; Cell Differentiation; Deoxyguanosine; Female; Gastric Mucosa; Gastritis; Humans; Male; Middle Aged; Nitric Oxide Synthase Type II; Peroxiredoxins; Stomach; Stomach Neoplasms; Young Adult

Infection with Helicobacter pylori strains may result in different pathological manifestations and increased oxidative stress leading to a strong inflammatory response in gastric mucosa.. The prevalence of cagA and vacA genes, proteins and the association of serum levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) with oxidative DNA damage were determined.. The presence of cagA gene and vacA alleles and IgG antibodies against CagA and VacA proteins were determined. Oxidative DNA damage status was determined using serum levels of 8-OHdG.. Helicobacter pylori-positive, cagA-positive, and vacA alleles (s1 and m2) were predominant in all clinical outcomes. There was no significant association between prevalence of CagA and VacA status and clinical outcomes. The serum levels of 8-OHdG was at a higher level in H. pylori-positive patients.. These virulence factors are not associated with the development of PUD in Iranian patients. H. pylori infection may be associated with increased serum 8-OHdG.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Aged, 80 and over; Antigens, Bacterial; Bacterial Proteins; Deoxyguanosine; DNA Damage; Enzyme-Linked Immunosorbent Assay; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Iran; Male; Middle Aged; Oxidative Stress; Polymerase Chain Reaction; Virulence

Reactive oxygen species (ROS) attack guanine bases in DNA and form 8-hydroxydeoxyguanosine (8-OHdG), which has been regarded simply as an oxidative mutagenic by-product. On the other hand, our previous report showed paradoxically ROS attenuating action of generated 8-OHdG. In the current study, both in vitro and in vivo experiments were executed in order to document anti-oxidative and anti-inflammatory actions of 8-OHdG in cell model and to elucidate the therapeutic efficacy against water immersion restraint stress (WIRS)-induced gastritis animal model. Electron spin resonance measurements showed that 8-OHdG at >5μg/ml completely scavenged OH(-) radicals, which was further confirmed by checking 2'-7'-dichlorodihydrofluorescein diacetate (DCFDA) spectroscopy. On molecular assay, 8-OHdG antagonized the action of GTP on Rac, a small GTP binding protein, without affecting Rac-guanosine exchange factor (GEF) or phosphoinositide 3-kinases (PI3K) activity. In Raw264.7 cells, 8-OHdG was found to be associated with marked attenuations of NOX1, NOXO1, and NOXA1 accompanied with the decreased expressions of LPS-induced inflammatory mediators including COX-2, iNOS, IL-1β, and IL-6. Similarly, 8-OHdG attenuated hypoxia-induced angiogenesis and platelet endothelial cell adhesion molecule-1 (PECAM-1), COX-2, iNOS, IL-8, and VEGF expressions in HUVEC cells. At transcriptional level, 8-OHdG inhibited the nuclear translocation of NF-κB, inhibitory κB kinase (IKK) β kinase activation, and decreased phospho-IκBα levels. 8-OHdG efficiently ameliorated WIRS-induced gastric mucosal injury as evidenced with improvement of gross lesion index and attenuation of engaging mediators. Taken together, exogenous 8-OHdG can be a functional molecule regulating oxidative stress-induced gastritis through either antagonizing Rac-GTP binding or blocking the signals responsible for gastric inflammatory cascade.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Anti-Inflammatory Agents; Antioxidants; Cell Line; Deoxyguanosine; Gastritis; Humans; Male; Mice; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Specific Pathogen-Free Organisms; Stress, Physiological; Transcription, Genetic

Helicobacter pylori (H pylori) infection induces chronic inflammation that can progress to gastric atrophy, intestinal metaplasia, and gastric adenocarcinoma. We have examined oxidative damage caused by Helicobacter pylori, metaplasia, and atrophy of gastric mucosal cells in patients with chronic gastritis by measuring their urinary 8-hydroxydeoxyguanosine (8-OHdG) levels.. We recruited 77 outpatients with chronic gastritis, confirmed by endoscopic examination. H pylori status was evaluated by histology (modified Giemsa staining), the H pylori stool antigen test (n=20), and the 13C urea breath test (n=27), as described in the Maastricht consensus report.. The mean amount of 8-OHdG (microg/g creatinine) in 77 subjects was 18.07 +/- 13.49 x 10(-3) microg/g creatinine. The levels of urinary 8-OHdG in the H pylori-positive gastritis patients were also significantly higher than those in the H pylori-negative gastritis patients (P=0.003, respectively, 20.42 +/- 13.33 x 10(-3) microg/g creatinine, 13.16 +/- 12.71 x 10(-3) microg/g creatinine). The level of urinary 8-OHdG was markedly higher in patients with gastric atrophy and intestinal metaplasia than in those without (P=0.000, P=0.002, respectively). There were significant correlations between levels of urinary 8-OHdG and both the atrophy score (r=0.441, P=0.000) and the intestinal metaplasia score (r=0.436, P=0.000).. Urinary 8-OHdG levels could be investigated in every patient with chronic gastritis, since it is a simple and completely noninvasive procedure. In patients with high levels of urinary 8-OHdG, endoscopic procedures or even pathological investigation may then be carried out, with the consideration that there is a high risk of intestinal metaplasia or atrophy.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Atrophy; Chronic Disease; Deoxyguanosine; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Intestinal Mucosa; Male; Metaplasia; Middle Aged; Prospective Studies

Oxidative stress is linked to gastric carcinogenesis because of its ability to damage DNA. Here we examined antioxidative and anti-inflammatory effects of 4-vinyl-2,6-dimethoxyphenol (canolol), a recently identified potent antioxidative compound obtained from crude canola oil, on Helicobacter (H.) pylori-induced gastritis and gastric carcinogenesis using a Mongolian gerbil model. The animals were allocated to H. pylori-infection alone (12 weeks) or H.pylori + N-methyl-N-nitrosourea (MNU) administration (52 weeks). After oral inoculation of H. pylori, they were fed for 10 and 44 weeks with or without 0.1% canolol. H. pylori-induced gastritis, 5'-bromo-2'-deoxyuridine (BrdU) labeling and scores for cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) immunohistochemistry were attenuated in the canolol-treated groups. Expression of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), COX-2 and iNOS mRNA in the gastric mucosa, and serum 8-hydroxy-2'-deoxyguanosine (8-OHdG), anti-H. pylori IgG and gastrin levels were also significantly lower in canolol-treated groups. Furthermore, the incidence of gastric adenocarcinomas was markedly reduced in the H. pylori + MNU + canolol-treated group [15.0% (6/40)] compared to the control group [39.4% (13/33)] (p < 0.05). These data indicate canolol to be effective for suppressing inflammation, gastric epithelial cell proliferation and gastric carcinogenesis in H. pylori-infected Mongolian gerbils. Interestingly, the viable H. pylori count was not changed by the canolol containing diet. Thus, the data point to the level of inflammation because of H. pylori rather than the existence of the bacteria as the determining factor. Importantly, canolol appears to suppress induction of mRNAs for inflammatory cytokines.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Anti-Inflammatory Agents; Antibodies, Bacterial; Antioxidants; Biomarkers; Cell Proliferation; Cell Transformation, Neoplastic; Cyclooxygenase 2; Deoxyguanosine; Disease Models, Animal; Gastric Mucosa; Gastrins; Gastritis; Gerbillinae; Helicobacter Infections; Helicobacter pylori; Immunoglobulin G; Immunohistochemistry; Interleukin-1beta; Nitric Oxide Synthase Type II; Oxidative Stress; Phenols; Polymerase Chain Reaction; RNA, Messenger; Stomach Neoplasms; Tumor Necrosis Factor-alpha; Vinyl Compounds

Epidemiological studies show that high intake of food-bound vitamin C and E reduces the risk of gastric cancer. Whether dietary supplementation with antioxidant micronutrients interferes with Helicobacter pylori infection and associated diseases is unclear. The aim of this study was to investigate if dietary vitamin C or E supplementation influences the progression of gastritis, gastric mucosal nitrosative and oxidative protein damage, gastric mucosal lipid peroxidation, or gastric mucosal oxidative DNA damage in H. pylori-infected Mongolian gerbils.. Gerbils were divided into four groups: H. pylori-infected animals fed with vitamin C- or vitamin E-supplemented food, and infected and uninfected animals given standard rodent food. Subgroups of animals were killed at different time-points until 52 weeks postinfection. Concentrations of 3-nitrotyrosine and thiobarbituric acid-reactive substances (TBARS) in the gastric mucosa were determined with an immunodot blot and a fluorometric method, respectively. Mucosal concentrations of carbonyl carbons on proteins and 8-hydroxydeoxyguanosine were determined by enzyme-linked immunosorbent assay. Gastritis was scored semiquantitatively.. Vitamin supplements had no effect on the colonization with H. pylori. Vitamin C as well as vitamin E supplements reduced mucosal 3-nitrotyrosine concentrations to normal levels in infected animals. Vitamin E supplements decreased mucosal protein carbonyls and TBARS in short-term gastritis. In addition, vitamin C supplements caused attenuated mucosal oxidative DNA damage and milder mucosal inflammation in short-term gastritis.. Vitamin C or vitamin E supplementation leads to some short-term protective effects on H. pylori-induced gastritis in Mongolian gerbils. These effects seem to subside over time when the infection persists.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Ascorbic Acid; Deoxyguanosine; Dietary Supplements; Disease Models, Animal; Gastric Mucosa; Gastritis; Gerbillinae; Helicobacter Infections; Helicobacter pylori; Male; Stomach Neoplasms; Thiobarbituric Acid Reactive Substances; Tyrosine; Vitamin E; Vitamins

Oxidative DNA damage is associated with Helicobacter pylori infection, atrophy and intestinal metaplasia. H. pylori-cagA-positive strains are associated with the highest risk of gastric cancer.. To ascertain whether cagA-positive H. pylori infection correlates with higher concentrations of 8OHdG and the presence of precancerous changes.. 118 patients were studied (65M/53F, age 61 +/- 14 years). Twelve were H. pylori-negative. Among the H. pylori-positive patients, 34 were cagA-positive and 40 were cagA negative. In 32 patients H. pylori had been eradicated at least 6 months before endoscopic sampling. The phenotype of the gastritis (atrophic compared with nonatrophic, with and without intestinal metaplasia) was scored in biopsy samples obtained from the antrum, corpus, and angularis incisura. In antral biopsy samples, 8-hydroxydeoxyguanosine was assessed by HPLC (electrochemical detector). CagA status was determined by PCR.. The highest scores for both mononuclear inflammation and activity of gastritis were significantly associated with cagA status (p = 0.036 antrum and p = 0.02 corpus). cagA-positive infection significantly correlated with a higher prevalence of atrophic-metaplastic lesions (p = 0.04). cagA-positive patients had higher 8-hydroxydeoxyguanosine levels than both cagA-negative and H. pylori-negative cases (p = 0.01). The 8-hydroxydeoxyguanosine levels were significantly higher in multifocal atrophic gastritis (p = 0.04). The odds ratio for cagA-positive patients having 8OHdG levels above a cut-off calculated on the basis of the ROC curves were 7.12, overall, reaching 11.25 when only patients younger than 50 were considered.. cagA-positive patients were characterized: first, for higher scores for gastritis, activity and atrophic and metaplastic lesions; and second for greater oxidative DNA damage overall, at younger age and in the presence of multifocal atrophy. This setting may represent a cancer-prone biological context.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Antigens, Bacterial; Bacterial Proteins; Deoxyguanosine; DNA Adducts; DNA Damage; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Intestines; Male; Metaplasia; Middle Aged; Oxidative Stress; Phenotype; Regression Analysis; Stomach Neoplasms

Although Helicobacter pylori is a risk factor for gastric cancer, the role of the bacterium in the development of this malignancy is not defined precisely. Reactive oxygen species (ROS) could play an important role in carcinogenesis by inducing DNA damage. The aims of the present study were: 1) to assess the production of ROS and 8-hydroxy-2'-deoxyguanosine (8-OHdG), a sensitive marker of oxidative DNA injury, in gastric mucosa, according to H. pylori status and cytotoxic associated gene product A (CagA); 2) to determine the relationship between ROS generation and amount of 8-OHdG.. Gastric biopsy specimens were obtained from 60 consecutive patients. ROS generation was measured by luminol enhanced chemiluminescence. 8-OHdG detection was performed by an immunoperoxidase method, using a specific anti 8-OHdG monoclonal antibody.. 40/60 patients (67%) were H. pylori-positive. ROS generation was significantly higher in patients positive for H. pylori infection as compared to negative. 8-OHdG detection was performed in 30 patients in which CagA presence was also investigated. High expression of 8-OHdG was detected in 14/20 (70%) H. pylori-positive patients (13 CagA+ and 1 CagA-) and in 2/10 (20%) H. pylori-negative patients. A significant correlation was found between ROS production and 8-OHdG content.. H. pylori infection by a CagA+ strain is associated with the highest production of ROS to which a severe oxidative DNA damage corresponds. This sequence of events could support the hypothesis that the oxygen-free radicals-mediated damage due to H. pylori cytotoxic strains could be a driving force that leads from chronic gastritis to gastric carcinoma.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Antigens, Bacterial; Bacterial Proteins; Chronic Disease; Deoxyguanosine; DNA Damage; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Immunoenzyme Techniques; Luminescent Measurements; Male; Middle Aged; Reactive Oxygen Species; Stomach Neoplasms

Helicobacter pylori infection causes gastric diseases, but the responsible mechanisms are not completely understood. They can involve DNA and tissue damage induced by reactive oxygen and nitrogen species. Our aim is to investigate the effects of bacterial eradication on oxidative stress by measuring changes of relevant markers.. Antral biopsies were obtained from 34 patients with chronic atrophic gastritis and peptic ulcer disease before and after bacterial eradication. The expression of inducible nitric oxide synthase (iNOS) and levels of nitrotyrosine (NTYR) and 8-hydroxy-2'-deoxyguanosine were assessed immunohistochemically as markers of nitric oxide (NO) production and of damage to proteins and DNA, respectively.. Before treatment, the percentages of patients with staining were: 56 for iNOS in inflammatory cells, 79 and 61 for NTYR and 8-hydroxy-2'-deoxyguanosine in foveolar cells, respectively, and 82 for 8-hydroxy-2'-deoxyguanosine in lymphoid follicles. NTYR staining was associated with the intensity of inflammation (p = 0.04) and gastritis activity (p = 0.07). The prevalence of 8-hydroxy-2'-deoxyguanosine tended to be associated with that of NTYR. After successful H. pylori eradication, the prevalence of iNOS and NTYR (in mild gastritis) staining decreased (p < 0.001 and p < 0.06, respectively). 8-Hydroxy-2'-deoxyguanosine staining disappeared in 24% of cases but appeared in 18% of previously negative cases despite eradication.. Targets of oxidative stress associated with H. pylori infection are inflammatory and deep foveolar cells and lymphoid follicles. This is the first report of 8-hydroxy-2'-deoxyguanosine localization in gastric mucosa. Oxidative stress is reduced by bacterial eradication in the first stages of mild gastritis. Moderate-severe gastritis may be a step that is reversible for iNOS, but partly irreversible for NTYR and 8-hydroxy-2'-deoxyguanosine.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Biomarkers; Chronic Disease; Deoxyguanosine; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Immunohistochemistry; Male; Middle Aged; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Oxidative Stress; Peptic Ulcer; Tyrosine

Gastric carcinogenesis is a multifactorial, multistep process, in which chronic inflammation plays a major role.. In order to ascertain whether free radical mediated oxidative DNA damage is involved in such a process, concentrations of 8-hydroxydeoxyguanosine (8OHdG), a mutagenic/carcinogenic adduct, and thiobarbituric acid reactive substances (TBARS), as an indirect measure of free radical mediated damage, were determined in biopsy specimens from patients undergoing endoscopy.. Eighty eight patients were divided into histological subgroups as follows: 27 with chronic non-atrophic gastritis, 41 with atrophic gastritis, six with gastric cancer, and 14 unaffected controls.. Intestinal metaplasia, Helicobacter pylori infection, and disease activity were semiquantitatively scored. 8OHdG concentrations were assessed by HPLC with electrochemical detection, and TBARS concentrations were fluorimetrically assayed.. 8OHdG concentrations (mean number of adducts/10(5) dG residues) were significantly higher in chronic atrophic gastritis (p = 0.0009). Significantly higher concentrations were also detected in the presence of severe disease activity (p = 0.02), intestinal metaplasia (p = 0.035), and H pylori infection (p = 0.001). TBARS concentrations were also higher in atrophic gastritis, though not significantly so. In a multiple logistic regression analysis, 8OHdG concentrations correlated best with the presence and severity of H pylori infection (r = 0.53, p = 0.002).. Chronic gastritis is characterised by the accumulation of oxidative DNA damage with mutagenic and carcinogenic potential. H pylori infection is the major determinant for DNA adduct formation.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Aged, 80 and over; Analysis of Variance; Ascorbic Acid; Chronic Disease; Deoxyguanosine; DNA Damage; Female; Gastric Juice; Gastritis; Gastroscopy; Helicobacter Infections; Helicobacter pylori; Humans; Male; Middle Aged; Reactive Oxygen Species; Regression Analysis; Stomach Neoplasms; Thiobarbituric Acid Reactive Substances

The purpose of this study was to study the changes of 8-hydroxydeoxyguanosine (8-OH-dG) contents of DNA from human gastric mucosa with or without Helicobacter pylori and the changes of two biomarkers, iNOS and apoptosis, in gastric biopsies obtained before and after the eradication of H. pylori.. DNA isolated from the biopsied human gastric mucosa was digested to deoxynucleotides by nuclease P1, then with Escherichia coli alkaline phosphatase, and analyzed by HPLC-ECD system. 8-OH-dG content was expressed as the number of residues per 10(5) deoxyguanosine. iNOS immunohistochemical staining was performed with antihuman iNOS antiserum generated in mice at a dilution of 1:500, and in situ apoptosis was detected by in situ terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick end labeling. Both the density of H. pylori and the degree of inflammation were scored.. The 8-OH-dG contents of healthy normal controls with negative H. pylori were 4.31 +/- 2.33 (8-OH-dG/10(5) dG), whereas those of patients with positive H. pylori were 10.40 +/- 7.25. The difference between these two values was statistically significant (p < 0.01). The 8-OH-dG contents were significantly decreased after the eradication of H. pylori (12.22 +/- 2.09 vs. 2.42 +/- 1.22, p < 0.001). After the eradication of H. pylori, both the apoptotic index and the iNOS scores were significantly decreased, compared with those before eradication (3.72 +/- 1.74 vs. 1.17 +/- 1.06 for apoptosis and 10.34 +/- 6.79 vs. 1.43 +/- 1.14 for iNOS, p < 0.001). Statistically significant correlations were observed among apoptotic index, iNOS score, degree of inflammation, and density of H. pylori (p < 0.05).. The increased levels of oxidative DNA damage, increased occurrences of apoptosis, and increased expressions of iNOS suggest mechanistic links between H. pylori infection and gastric carcinogenesis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adolescent; Adult; Aged; Animals; Apoptosis; Deoxyguanosine; DNA; DNA Damage; DNA Nucleotidylexotransferase; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Immunohistochemistry; Mice; Middle Aged; Nitric Oxide Synthase; Stomach Neoplasms

Helicobacter pylori causes type B gastritis. It shows strong association with the development of gastric carcinoma. A plausible hypothesis for the missing link between H. pylori infection and gastric carcinogenesis involves oxygen free radical-induced DNA damage. To test this hypothesis, we compared the amount of 9-hydroxydeoxyguanosine, a marker for oxygen free radical-induced DNA damage, in the DNA of human gastric mucosa with and without H. pylori infection. Gastric antral biopsies were taken from pediatric patients and volunteers to select H. pylori-positive and H. pylori-negative specimens. The 8-hydroxydeoxyguanosine content of the gastric mucosal DNA was measured after H. pylori-positive and H. pylori-negative volunteers were identified. The increased level of oxidative DNA damage suggests the mechanistic link between H. pylori infection and gastric carcinoma.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adolescent; Child; Child, Preschool; Deoxyguanosine; DNA; DNA Damage; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Infant; Male; Reactive Oxygen Species