8-hydroxy-2--deoxyguanosine and Helicobacter-Infections

Peptic ulcer is considered an important public health problem and generally associated with complicated conditions such as bleeding and perforation. The aim of this study is to reflect the rate of oxidative damage in the body among dyspeptic patients with Helicobacter pylori-positive peptic ulcer by measuring 8-hydroxy-2'-deoxyguanosine (8-OHdG) level in serum samples and its association with the level of bacterial endotoxin.. Patients referred to Harran University Gastroenterology Outpatient Clinic with dyspeptic complaints were enrolled in this study. According to gastrointestinal endoscopy findings, 43 dyspeptic patients with H pylori-positive peptic ulcer patients and 43 healthy volunteers were included in this study. Infection with H pylori was diagnosed by H pylori urea breath and stool antigen tests. Serum 8-OHdG and endotoxins were measured by ELISA.. A total of 43 dyspeptic patients with peptic ulcer (13 women and 30 men) and 43 healthy individuals (16 women and 27 men) were enrolled in the study. In biopsies taken endoscopically, H pylori severity was mild in 19 patients (43.9%), moderate in 21 patients (48.5%) and severe in 3 patients (7.6%). 8-OHdG was compared with the healthy and patient group. It was observed that there was a statistically significant difference (P < .01). In addition, a weak correlation was found between OHdG and bacterial endotoxin.. Serum 8-OHdG and endotoxin levels are only weakly associated implying that they reflect specific aspects of oxidative damage. Helicobacter pylori and its endotoxin have a significant role in peptic ulcer pathogenesis. The detection of serum 8-OHdG in dyspeptic patients may be used as a biomarker for the presence of peptic ulcers.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Endotoxins; Female; Helicobacter Infections; Helicobacter pylori; Humans; Male; Peptic Ulcer

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

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

Infection with Helicobacter pylori (H. pylori) can induce gastric disorders, and though its presence cannot explain disease pathogenesis and does not have associations with other factors, it is well known that H. pylori infection causes stomach inflammation following oxidative stress. We examined the suppressive effects of a leaf extract of Wasabia japonica on H. pylori infection and on stress loading in Mongolian gerbils. Following oral administration of wasabi extract of 50 and 200 mg/kg B.W./d for 10 d, the animals were exposed to restraint stress for 90 and 270 min. As for the results, the level of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in the stomach and oxidative DNA damage in peripheral erythrocytes at 270 min significantly increased. That elevation was significantly suppressed by the addition of the leaf extract. We concluded that the simultaneous loading of H. pylori infection and physical stress loading might induce oxidative DNA damage additively, while a leaf extract attenuated this DNA damage in the stomach as well as the peripheral erythrocytes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Deoxyguanosine; DNA Damage; Gastric Mucosa; Gerbillinae; Helicobacter Infections; Helicobacter pylori; Male; Mongolia; Oxidative Stress; Plant Extracts; Plant Leaves; Restraint, Physical; Stomach; Stress, Psychological; Wasabia

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

Infection by Helicobacter pylori is the most important risk factor for gastric cancer. However, only a small fraction of colonized individuals, representing at least half of the world's population, develop this malignancy. In order to shed light on host-microbial interactions, gastric mucosa biopsies were collected from 119 patients suffering from dyspeptic symptoms. 8-Hydroxy-2'-deoxyguanosine (8-oxo-dG) levels in the gastric mucosa were increased in carriers of H.pylori, detected either by cultural method or by polymerase chain reaction, and were further increased in subjects infected with strains positive for the cagA gene, encoding the cytotoxin-associated protein, cagA. Oxidative DNA damage was more pronounced in males, in older subjects, and in H.pylori-positive subjects suffering from gastric dysplasia. Moreover, 8-oxo-dG levels were significantly higher in a small subset of subjects having a homozygous variant allele of the 8-oxoguanosine-glycosylase 1 (OGG1) gene, encoding the enzyme removing 8-oxo-dG from DNA. Conversely, they were not significantly elevated in glutathione S-transferase M1 (GSTM1)-null subjects. Thus, both bacterial and host gene polymorphisms affect oxidative stress and DNA damage, which is believed to represent a key mechanism in the pathogenesis of gastric cancer. The interplay between bacterial and host gene polymorphisms may explain why gastric cancer only occurs in a small fraction of H.pylori-infected individuals.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adolescent; Adult; Aged; Aged, 80 and over; Antigens, Bacterial; Bacterial Proteins; Child; Deoxyguanosine; DNA Damage; DNA Glycosylases; DNA, Viral; Dyspepsia; Female; Gastric Mucosa; Glutathione Transferase; Helicobacter Infections; Helicobacter pylori; Humans; Immunoenzyme Techniques; Male; Middle Aged; Oxidative Stress; Reactive Oxygen Species; Stomach Neoplasms

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

Both Helicobacter pylori (Hp) and bile acids are gastric carcinogens. An experimental model of duodenogastric reflux in Mongolian gerbils was developed and was used to study the effects of Hp infection and duodenogastric reflux on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced glandular stomach tumorigenesis independently and synergistically. Male Mongolian gerbils underwent both inoculation with Hp, and had duodenogastric reflux (DR) induced, or neither, followed by MNNG administration. Animals were sacrificed at week 40, and histopathological examination of their excised stomachs and serological investigation were performed. Glandular stomach adenocarcinomas were observed in animals that underwent Hp inoculation and/or induction of DR after MNNG administration, and glandular stomach adenomas were found in animals inoculated with Hp after MNNG administration. The incidence of glandular stomach tumors was significantly higher in animals inoculated with Hp after MNNG administration and in animals undergoing combined Hp inoculation, DR induction and MNNG administration than in animals only administered MNNG. These findings indicate that Hp infection has a stronger tumorigenic effect than the exposure to duodenal contents, and duodenal contents may attenuate the effect of Hp on glandular stomach tumorigenesis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Deoxyguanosine; Duodenogastric Reflux; Gastrointestinal Contents; Gerbillinae; Helicobacter Infections; Inflammation; Male; Methylnitronitrosoguanidine; Mongolia; Neoplasms, Glandular and Epithelial; Stomach Neoplasms

Helicobacter pylori infection causes chronic inflammation, which can lead to gastric carcinoma. A double immunofluorescence labeling study demonstrated that the level of 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) apparent in gastric gland epithelium was significantly higher in gastritis patients with H. pylori infection than in those without infection. A significant accumulation of proliferating cell nuclear antigen, a prognostic factor for gastric cancer, was observed in gastric gland epithelial cells in patients with H. pylori infection as compared to those without infection, and its accumulation was closely correlated with the formation of 8-nitroguanine and 8-oxodG. These results suggest that nitrosative and oxidative DNA damage in gastric epithelial cells and their proliferation by H. pylori infection may lead to gastric carcinoma. 8-Nitroguanine could be not only a promising biomarker for inflammation but also a useful indicator of the risk of gastric cancer development in response to chronic H. pylori infection.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Deoxyguanosine; Female; Gastric Mucosa; Guanine; Helicobacter Infections; Helicobacter pylori; Humans; Male; Middle Aged; Proliferating Cell Nuclear Antigen

To prepare monoclonal antibodies against oh(8)dG and to evaluate the relationship between Hp infection and oxidative DNA damage by detecting oh8dG in gastric mucosa.. BALB/C mice were immunized with BSA-oh(8)dG conjugate, monoclonal antibodies were prepared by hybridoma technique, the biological characteristics of antibodies were analysed by competitive ELISA, Western blot and immunohistochemistry.. Two strains of hybridoma cell were obtained. ELISA and Western blot indicated that the antibodies were fairly specific for oh(8)dG. In immunohistochemistry,the positive rate of oh(8)dG expression in Hp positive tissues and Hp negative tissues was 55% and 5%, respectively(P<0.01).. The prepared antibodies can specially recognize oh(8)dG and immunohistochemistry with the monoclonal antibodies showed Hp infection can increase oh(8)dG level in gastric mucosa.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antibodies, Monoclonal; Blotting, Western; Deoxyguanosine; Enzyme-Linked Immunosorbent Assay; Female; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Immunohistochemistry; Mice; Mice, Inbred BALB C

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

A number of reports have implicated oxygen free radicals in the pathogenesis of Helicobacter pylori (H. pylori)-associated disease. 8-hydroxydeoxyguanosine (8-OHdG) has recently been accepted as a sensitive marker for reflecting the oxidative DNA damage. However, there have been no previous studies comparing the changes in urinary 8-OHdG excretions before and after therapy for eradication of H. pylori infection, or to examine 8-OHdG excretions in children with H. pylori infection. The aim of this study was therefore to examine the DNA damage in gastric mucosal cells in children with H. pylori infection.. Urinary 8-OHdG excretions were measured before and after therapy for eradication of H. pylori infection in 15 children diagnosed with the H. pylori infection and 13 parents who were also suffering from the same infection.. In both the children and their parents, no significant differences were found in urinary 8-OHdG excretions either before or after the eradication therapy. Furthermore, there was no significant difference in urinary 8-OHdG excretions between 8 children with peptic ulcers and 7 children without ulcers, either before or after the therapy.. These results suggest that measurement of urinary 8-OHdG levels is not useful for evaluation of the DNA damage in H. pylori-infected gastric mucosa in children.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Breath Tests; Child; Deoxyguanosine; DNA Damage; Female; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Humans; Male

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

To assess whether Helicobacter pylori-related inflammation increases oxidative DNA damage, we evaluated the association between H. pylori infection and urinary excretion of an adduct of oxidative DNA damage, 8-hydroxy-2-deoxyguanosine (8ohdG). Subjects included 555 healthy persons, ages 20-39, within the Kaiser Permanente Medical Care Program in Northern California. We tested sera for antibodies to H. pylori by ELISA; collected demographic, dietary, smoking, and alcohol data by questionnaire; and assayed 24-h urine samples for 8ohdG with a newly developed ELISA kit. Two hundred eighty-one subjects provided adequate 24-h urine samples for 8ohdG and creatinine assays and had detectable levels of 8ohdG. After adjusting for 24-h urinary creatinine (Ucr) and demographic factors, persons without H. pylori infection had significantly higher amounts of 24-h urinary 8ohdG than infected persons (geometric mean, 18.04 microg 8ohdG/Ucr g versus 14.36 microg 8ohdG/Ucr g, respectively; P = 0.008). Excretion of 8ohdG was higher in whites and Hispanics (17.44 and 18.09 microl/Ucr g) than in blacks (13.21 microg/Ucr g; P < 0.001). Gender was not significantly associated with 8ohdG excretion (16.18 microg/Ucr g for males versus 16.01 microg/Ucr g for females; P = 0.883). Of the dietary factors evaluated, vitamin C negatively correlated (P < 0.001) and carbohydrate intake positively correlated with 8ohdG excretion (P = 0.003). Infection with H. pylori was strongly associated with decreased 8ohdG excretion in the urine. This unexpected finding suggests either that DNA repair is deficient in infected subjects, that inflammation destroys the adduct, or that urinary 8ohdG is not an accurate measure of gastric damage.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Biomarkers; Creatinine; Deoxyguanosine; Diet; DNA Adducts; DNA Damage; Enzyme-Linked Immunosorbent Assay; Female; Helicobacter Infections; Helicobacter pylori; Humans; Immunoglobulin A; Male; Oxidative Stress; Reproducibility of Results; Sensitivity and Specificity; Sex Factors

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

A recently discovered bacterium, Helicobacter hepaticus, infects the intrahepatic bile canaliculi of mice, causing a severe chronic hepatitis culminating in liver cancer. Thus, it affords an animal model for study of bacteria-associated tumorigenesis including H. pylori-related gastric cancer. Reactive oxygen species are often postulated to contribute to this process. We now report that hepatitis of male mice infected with H. hepaticus show significant increases in the oxidatively damaged DNA deoxynucleoside 8-hydroxydeoxyguanosine, with the degree of damage increasing with progression of the disease. Perfusion of infected livers with nitro blue tetrazolium revealed that superoxide was produced in the cytoplasm of hepatocytes, especially in association with plasmacytic infiltrates near portal triads. Contrary to expectations, Kupffer cells, macrophages, and neutrophils were rarely involved. However, levels of cytochrome P450 (CYP) isoforms 1A2 and 2A5 in hepatocytes appeared to be greatly increased, as indicated by the number of cells positive in immunohistochemistry and the intensity of staining in many cells, concomitant with severe hepatitis. The CYP2A5 immunohistochemical staining co-localized with formazan deposits resulting from nitro blue tetrazolium reduction and occurred in nuclei as well as cytoplasm. These findings suggest that CYP2A5 contributes to the superoxide production and 8-hydroxydeoxyguanosine formation, although reactive oxygen species from an unknown source in the hepatocytes leading to CYP2A5 induction or coincidental occurrence of these events are also possibilities. Three glutathione S-transferase isoforms, mGSTP1-1 (pi), mGSTA1-1 (YaYa), and mGSTA4-4, also showed striking increases evidencing major oxidative stress in these livers.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Aryl Hydrocarbon Hydroxylases; Cytochrome P-450 CYP1A2; Cytochrome P-450 CYP2A6; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 2; Deoxyguanosine; DNA Damage; Glutathione Transferase; Helicobacter; Helicobacter Infections; Hepatitis, Animal; Immunoblotting; Immunohistochemistry; Liver; Male; Mice; Mixed Function Oxygenases; Reactive Oxygen Species; Superoxides

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