Effects of antioxidant vitamin supplements on Helicobacter pylori-induced gastritis in Mongolian gerbils

The nutraceutical electrophile scavenger 2-hydroxybenzylamine (2-HOBA) attenuates gastric cancer development caused by Helicobacter pylori

Stomach cancer is a leading cause of cancer death. Helicobacter pylori is a bacterial gastric pathogen that is the primary risk factor for carcinogenesis, associated with its induction of inflammation and DNA damage. Dicarbonyl electrophiles are generated from lipid peroxidation during the inflammatory response and form covalent adducts with amine-containing macromolecules. 2-hydroxybenzylamine (2-HOBA) is a natural compound derived from buckwheat seeds and acts as a potent scavenger of reactive aldehydes. Our goal was to investigate the effect of 2-HOBA on the pathogenesis of H. pylori infection. We used transgenic FVB/N insulin-gastrin (INS-GAS) mice as a model of gastric cancer. First, we found that 2-HOBA is bioavailable in the gastric tissues of these mice after supplementation in the drinking water. Moreover, 2-HOBA reduced the development of gastritis in H. pylori-infected INS-GAS mice without affecting the bacterial colonization level in the stomach. Further, we show that the development of gastric dysplasia and carcinoma was significantly reduced by 2-HOBA. Concomitantly, DNA damage were also inhibited by 2-HOBA treatment in H. pylori-infected mice. In parallel, DNA damage was inhibited by 2-HOBA in H. pylori-infected gastric epithelial cells in vitro. In conclusion, 2-HOBA, which has been shown to be safe in human clinical trials, represents a promising nutritional compound for the chemoprevention of the more severe effects of H. pylori infection.

The influence of the dietary intake of vitamin C and vitamin E on the risk of gastric intestinal metaplasia in a cohort of Koreans

OBJECTIVES

Studies have suggested that the dietary intake of antioxidant vitamins, such as vitamin C and vitamin E, has a potential role in inhibiting gastric carcinogenesis. The present study investigated the effect of antioxidant vitamins on the incidence of gastric intestinal metaplasia (GIM).

METHODS

This study included 67,657 Koreans free of GIM who periodically underwent health check-ups. Dietary intake was assessed by a semiquantitative food frequency questionnaire based on the Korean National Health and Nutrition Examination Survey. Participants were categorized into 4 groups by quartiles of dietary vitamin C and vitamin E intake. The Cox proportional hazard assumption was used to determine the multivariable hazard ratio (HR) and 95% confidence interval (95% CI) for GIM.

RESULTS

The third and fourth quartiles of vitamin C intake had a lower risk of GIM than the first quartile (multivariable-adjusted HR, 0.95; 95% CI, 0.88 to 1.03 in the second quartile, HR, 0.88; 95% CI, 0.81 to 0.97 in the third quartile, and HR, 0.85; 95% CI, 0.76 to 0.95 in the fourth quartile). Vitamin E intake greater than the second quartile level was significantly associated with a lower risk of GIM than the first quartile (multivariable-adjusted HR, 0.90; 95% CI, 0.82 to 0.97 in the second quartile, HR, 0.90; 95% CI, 0.82 to 0.99 in the third quartile, and HR, 0.83; 95% CI, 0.74 to 0.94 in the fourth quartile). This association was observed only in the subgroup analysis for men.

CONCLUSIONS

Higher dietary intake of vitamin C and vitamin E was associated with a lower risk of GIM.

The Effects of Vitamins and Micronutrients on Helicobacter pylori Pathogenicity, Survival, and Eradication: A Crosstalk between Micronutrients and Immune System

Helicobacter pylori as a class I carcinogen is correlated with a variety of severe gastroduodenal diseases; therefore, H. pylori eradication has become a priority to prevent gastric carcinogenesis. However, due to the emergence and spread of multidrug and single drug resistance mechanisms in H. pylori, as well as serious side effects of currently used antibiotic interventions, achieving successful H. pylori eradication has become exceedingly difficult. Recent studies expressed the intention of seeking novel strategies to improve H. pylori management and reduce the risk of H. pylori-associated intestinal and extragastrointestinal disorders. For which, vitamin supplementation has been demonstrated in many studies to have a tight interaction with H. pylori infection, either directly through the regulation of the host inflammatory pathways or indirectly by promoting the host immune response. On the other hand, H. pylori infection is reported to result in micronutrient malabsorption or deficiency. Furthermore, serum levels of particular micronutrients, especially vitamin D, are inversely correlated to the risk of H. pylori infection and eradication failure. Accordingly, vitamin supplementation might increase the efficiency of H. pylori eradication and reduce the risk of drug-related adverse effects. Therefore, this review aims at highlighting the regulatory role of micronutrients in H. pylori-induced host immune response and their potential capacity, as intrinsic antioxidants, for reducing oxidative stress and inflammation. We also discuss the uncovered mechanisms underlying the molecular and serological interactions between micronutrients and H. pylori infection to present a perspective for innovative in vitro investigations, as well as novel clinical implications.

Sinapic Acid and Its Derivatives as Medicine in Oxidative Stress-Induced Diseases and Aging

Sinapic acid (3,5-dimethoxy-4-hydroxycinnamic acid) is an orally bioavailable phytochemical, extensively found in spices, citrus and berry fruits, vegetables, cereals, and oilseed crops and is known to exhibit antioxidant, anti-inflammatory, anticancer, antimutagenic, antiglycemic, neuroprotective, and antibacterial activities. The literature reveals that sinapic acid is a bioactive phenolic acid and has the potential to attenuate various chemically induced toxicities. This minireview is an effort to summarize the available literature about pharmacokinetic, therapeutic, and protective potential of this versatile molecule in health related areas.

Helicobacter pylori infection and eye diseases: a systematic review

The connection between Helicobacter pylori (Hp) infection and eye diseases has been increasingly reported in the literature and in active research. The implication of this bacterium in chronic eye diseases, such as blepharitis, glaucoma, central serous chorioretinopathy and others, has been hypothesized. Although the mechanisms by which this association occurs are currently unknown, this review describes shared pathogenetic mechanisms in an attempt to identify a lowest common denominator between eye diseases and Hp infection. The aim of this review is to assess whether different studies could be compared and to establish whether or not Hp infection and Eye diseases share common pathogenetic aspects. In particular, it has been focused on oxidative damage as a possible link between these pathologies. Text word search in Medline from 1998 to July 2014. 152 studies were included in our review. Were taken into considerations only studies that related eye diseases more frequent and/or known. Likely oxidative stress plays a key role. All of the diseases studied seem to follow a common pattern that implicates a cellular response correlated with a sublethal dose of oxidative stress. These alterations seem to be shared by both Hp infections and ocular diseases and include the following: decline in mitochondrial function, increases in the rate of reactive oxygen species production, accumulation of mitochondrial DNA mutations, increases in the levels of oxidative damage to DNA, proteins and lipids, and decreases in the capacity to degrade oxidatively damaged proteins and other macromolecules. This cascade of events appears to repeat itself in different diseases, regardless of the identity of the affected tissue. The trabecular meshwork, conjunctiva, and retina can each show how oxidative stress may acts as a common disease effector as the Helicobacter infection spreads, supported by the increased oxidative damage and other inflammation.

Association between dietary antioxidant vitamins intake/blood level and risk of gastric cancer

We aimed to systematically evaluate the association between dietary intake/blood levels of antioxidant vitamins (vitamin C, vitamin E, β-carotene, and α-carotene) and gastric cancer risk. Systematic literature searches were conducted until April 2013 in Pubmed and Embase to identify relevant studies. Either a fixed- or a random-effects model was adopted to estimate overall odds ratios (ORs). Dose-response, meta-regression, subgroup, and publication bias analyses were applied. Forty articles were finally included in the present study. Higher dietary intake of vitamin C, vitamin E, β-carotene, and α-carotene was inversely associated with gastric cancer risk (for vitamin C, pooled OR=0.58, 95% CI 0.51-0.65; for vitamin E, pooled OR=0.65, 95% CI 0.57-0.74; for β-carotene, pooled OR=0.59, 95% CI 0.49-0.70; for α-carotene, pooled OR=0.69, 95% CI 0.52-0.93). Subgroup analyses suggested the effects of these antioxidant vitamins were different in gastric cancer subtypes. As indicated by dose-response analysis, a 100 mg/day increment of vitamin C intake conferred an OR of 0.78 (95% CI 0.67-0.90); a 15 mg/day increment of vitamin E intake conferred an OR of 0.79 (95% CI 0.66-0.94); and a 5 mg/day increment in β-carotene intake conferred an OR of 0.80 (95% CI 0.60-1.04). No significant association was observed between blood vitamin C, α-tocopherol, γ- tocopherol, β-carotene and α-carotene levels and gastric cancer risk. In conclusion, dietary intake of vitamin C, vitamin E, β-carotene and α-carotene was inversely associated with gastric cancer risk while no such association was observed for blood levels of these antioxidant vitamins, thus the results should be interpreted cautiously.

Effects of alpha tocopherol and ascorbic acid on Helicobacter pylori colonization and the severity of gastric inflammation

BACKGROUND AND AIM

We aimed to evaluate the changes in histopathologic features, concentrations of vitamins C and E in gastric mucosa, and total antioxidant capacity of the body after ingestion of ascorbic acid and alpha tocopherol in patients with Helicobacter pylori.

MATERIAL AND METHOD

Patients with H. pylori-positive nonulcer dyspepsia were included in this study. Tissue samples were taken from the lesser and greater curvature in both prepyloric antrum and corpus for histopathologic examination and measurement of vitamins C and E concentrations. Blood samples were obtained for measurement of the total antioxidant capacity of the body. The patients were given vitamin C 500 mg BID and vitamin E 200 IU BID for 4 weeks orally. At the end of the 4th week, the initial procedures were repeated. Histopathologic examination of the tissue samples were carried out by two pathologists.

RESULTS

The mean vitamins C and E concentrations in gastric mucosa at the 4th week were higher than those at the beginning (p = .000 and p = .006, respectively). Mean total antioxidant capacity of the body at the beginning and that at the 4th week were similar (p = .689). H. pylori intensity in the antrum at the beginning was higher than that at the 4th week for both pathologists (p = .007 and p = .039). Neutrophilic activity in the antrum at the beginning was higher than that at the 4th week for both pathologists (p = .000 and p = .025). Neutrophilic activity in the corpus at the beginning was higher than that at the 4th week for pathologist 1 (p = .033), and they were similar for pathologist 2 (p = .763).

CONCLUSION

The findings that H. pylori intensity and neutrophilic activity decrease through increasing gastric ascorbic acid and alpha tocopherol concentrations suggest that supplementation with vitamins C and E increases the eradication rates via impairing the microenvironment created by the bacteria and facilitating the diffusion of antibiotics into gastric mucosa.

Effect of vitamins C and E supplementation on Helicobacter pylori eradication: a meta-analysis

Vitamins C and E can act as potent antioxidants to reduce the damage caused by reactive oxygen species in gastric mucosa. Whether vitamin supplements for Helicobacter pylori eradication regimen could improve the rate of eradication remains uncertain. Therefore, we performed a meta-analysis to evaluate the efficacy of vitamins C and E supplementation for the eradication of H. pylori. Searches were conducted in the databases PubMed, EMBASE and Cochrane Library. Randomised controlled trials (RCT) that fulfilled the inclusion criteria and addressed the clinical questions of this analysis were further assessed. Of the six RCT included, five had a low methodological quality. Of the six RCT, three compared the efficacy of the eradication regimen v. eradication regimen plus vitamins C and E. The result of the meta-analysis showed a non-significant difference in the eradication rate of H. pylori between the two groups (risk ratio (RR) 0·93, P = 0·76). Another three RCT compared the eradication regimen v. eradication regimen plus vitamin C only, and there too there was no significant difference in the eradication rate (RR 0·83, P = 0·32). In conclusion, vitamins C and/or E supplements to the H. pylori eradication regimen could not improve the eradication rate. However, currently available data do not draw a definitive conclusion about the effectiveness of antioxidant vitamins on H. pylori eradication, owing to the small sample size and low-to-moderate methodological quality.

Efficacy of vitamins supplementation to therapy on Helicobacter pylori eradication in patients with low antioxidant capacity

BACKGROUND AND OBJECTIVES

It was shown that supplementation of vitamins C and E to therapy increased Helicobacter pylori eradication rate. In the present study, we aimed to evaluate whether supplementation of antioxidant vitamins to therapy increases H. pylori eradication rates in patients with chronic stress and low antioxidant capacity.

METHODS

This study included 120 patients who presented to gastroenterology outpatient clinic with H. pylori-positive nonulcer dyspepsia and low total antioxidant capacity. Patients in group A (n=80) were given lansoprazole (30 mg, BID), amoxicillin (1000 mg, BID), and clarithromycin (500 mg, BID) for 14 days, as well as vitamin C (500 mg, BID) and vitamin E (200 IU, BID) for 30 days. Patients in group B (n=40) were given lansoprazole (30 mg, BID), amoxicillin (1000 mg, BID), and clarithromycin (500 mg, BID) for 14 days.

RESULTS

Total antioxidant capacity were lower than normal levels in all patients. One hundred and fifteen patients (77 in group A, 38 in group B) were analyzed with per protocol analysis. In group A, H. pylori eradication was achieved in 63.8% of the patients included in the intention to treat analysis and in 66.2% of the patients included in the per protocol analysis. In group B, H. pylori eradication was achieved in 42.5% of the patients included in the intention to treat analysis and in 44.7% of the patients included in the per protocol analysis. Eradication rates were significantly higher in group A than in group B (P<0.005).

CONCLUSIONS

Supplementation with vitamins C and E increased H. pylori eradication rate of standard triple therapy.

Vitamin-C as anti-Helicobacter pylori agent: More prophylactic than curative- Critical review

Potential of nonantibiotic therapies for treatment of Helicobacter pylori-related acid peptic disease remains underexplored. Several clinical studies have shown that higher prevalence of H. pylori infection is associated with low Vitamin C (Vit C) level in serum and gastric juice. However, there is no consensus regarding the usefulness of Vit C supplementation in the management of H. pylori infection. Surveying the existing literature we conclude that high concentration of Vit C in gastric juice might inactivate H. pylori urease, the key enzyme for the pathogen's survival and colonization into acidic stomach. Once infection established, urease is not very important for its survival. The role of Vit-C as anti-H. pylori agent in peptic ulcer diseases appears to be preventive rather than curative. Rather than supplementing high dose of Vit C along with conventional triple therapy, it is preferable to complete the conventional therapy and thereafter start Vit C supplementation for extended period which would prevent reinfection in susceptible individuals, provided the patients are not achlorhydric. Further studies are required to prove the role of Vit C in susceptible population.

Suppressive Effects of Selected Food Phytochemicals on CD74 Expression in NCI-N87 Gastric Carcinoma Cells

Helicobacter pylori (H. pylori) is one of the most widespread human pathogens, and plays major roles in chronic gastritis and gastric cancer. CD74 of gastric epithelial cells has recently been identified as an adhesion molecule to urease in H. pylori. In this study, we found that CD74 is highly expressed in a constitutive manner in NCI-N87 human gastric carcinoma cells at both the protein and mRNA levels as compared with Hs738St./Int fetal gastric cells. Subsequently, a novel cell-based ELISA able to rapidly screen the suppressive agents of CD74 expression was established. NCI-N87 cells were treated separately with 25 different food phytochemicals (4–100 µM) for 48 h and subjected to our novel assay. From those results, a citrus coumarin, bergamottin, was indicated to be the most promising compound with an LC₅₀/IC₅₀ value greater than 7.1, followed by luteolin (>5.4), nobiletin (>5.3), and quercetin (>5.1). Our findings suggest that these CD74 suppressants are unique candidates for preventing H. pylori adhesion and subsequent infection with reasonable action mechanisms.

Supplementing vitamins C and E to standard triple therapy for the eradication of Helicobacter pylori

WHAT IS KNOWN AND OBJECTIVE

Helicobacter pylori eradication rates of currently accepted triple therapy regimens vary between geographic locations and do not exceed 70-80%. Eradication rates are much lower in locations where uncontrolled antibiotic use is common such as Turkey. In the present study, we aimed to test whether supplementing vitamins C and E to standard triple therapy, including a proton pump inhibitor plus amoxicillin plus clarithromycin, increased the H. pylori eradication rate.

METHODS

Two hundred patients infected with H. pylori were randomized into two groups in an open-label trial. In group A, patients (n = 160) were given standard triple therapy, including lansoprazole 30 mg BID plus amoxicillin 1000 mg BID plus clarithromycin 500 mg BID for 14 days, plus vitamin C 500 mg BID plus vitamin E 200 IU BID for 30 days. In group B, patients (n = 40) were given standard triple therapy for 14 days. The success of H. pylori eradication was defined as a negative ¹⁴C-urea breath test result, 4-6 weeks after the completion of therapy. Comaprisons were by both intention-to-treat (ITT) and per-protocol (PP) analysis.

RESULTS AND DISCUSSION

Two hundred patients (137 women, 63 men) were analysed using ITT analysis and 195 patients completed the study. In group A, H. pylori eradication was achieved in 132 of the 160 patients (82·5%) included in ITT analysis and 132 of the 157 patients (84%) included in PP analysis. In group B, H. pylori eradication was achieved in 18 of the 40 patients (45%) included in ITT analysis and 18 of the 38 patients (47·4%) included in PP analysis. Eradication rates were significantly higher in group A than in group B (P < 0·005). Eradication rates were not statistically significant between men and women in both groups.

WHAT IS NEW AND CONCLUSION

Adding vitamins C and E to standard triple therapy increases the eradication rate of H. pylori. Vitamins C and E may increase the eradication rate via increasing the effectiveness of the antibiotics by decreasing oxidative stress in the gastric mucosa and strengthening the immune system.

Redox biology and gastric carcinogenesis: the role of Helicobacter pylori

Almost half the world's population is infected by Helicobacter pylori (H. pylori). This bacterium increases the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in human stomach, and this has been reported to impact upon gastric inflammation and carcinogenesis. However, the precise mechanism by which H. pylori induces gastric carcinogenesis is presently unclear. Although the main source of ROS/RNS production is possibly the host neutrophil, H. pylori itself produces O₂•⁻. Furthermore, its cytotoxin induces ROS production by gastric epithelial cells, which might affect intracellular signal transduction, resulting in gastric carcinogenesis. Excessive ROS production in gastric epithelial cells can cause DNA damage and thus might be involved in gastric carcinogenesis. Understanding the molecular mechanism of H. pylori-induced carcinogenesis is important for developing new strategies against gastric cancer.

Helicobacter pylori, nutrition and smoking interactions: their impact in gastric carcinogenesis

Gastric cancer (GC) is the result of a long multi-step and multifactorial process involving possible interactions between Helicobacter pylori infection, environmental exposures and host genetic susceptibility. Interactions between H. pylori infection, tobacco smoking and dietary antioxidants are biologically plausible. Positive interactions between risk factors imply that, in certain subgroups of the population, the risk of GC associated with simultaneous exposure to these factors is higher than that in the rest of the population, and these subgroups have to be the target for preventive measures. Using PubMed, we reviewed all studies published in English up to December 2008 carried out in humans on interactions between H. pylori infection and smoking exposure and between H. pylori infection and dietary factors in gastric carcinogenesis. Although relatively few epidemiological studies have evaluated the effect of the interaction between smoking and H. pylori infection on GC risk, there is a suggestion of a positive interaction between the two factors. In contrast, evidence suggests a negative interaction between dietary antioxidants and H. pylori infections on GC risk. The potential protective effect of dietary antioxidants such as vitamins C and E and beta-carotene seems to be stronger in those infected by H. pylori, even though results are inconsistent. In Asian populations, subjects infected by H. pylori and with high dietary salt intake may have a higher risk of GC than subjects without H. pylori infection and with a low salt intake. The risk of GC associated with red meat, processed meat or endogenous formation of nitrosamines appears to only be observed in subjects infected by H. pylori. More and larger epidemiological studies, mainly prospective studies, are necessary to reach a more definitive conclusion on these interactions.

Oxidative stress in Helicobacter pylori infection: does supplementation with vitamins C and E increase the eradication rate?

AIM

This study aims to assess the antioxidant property of vitamins E and C in Helicobacter pylori infection, and to determine if adding them to standard triple therapy plus bismuth subcitrate increases the H. pylori eradication rate.

METHODS

This study included 160 patients infected with H. pylori, who were randomized into one of two groups. Patients in group A (n = 80) received lansoprazole (30 mg, b.i.d.), amoxicillin (1000 mg, b.i.d.), clarithromycin (500 mg, b.i.d.), and bismuth subcitrate (300 mg, q.i.d.) for 14 days, while patients in group B (n = 80) received vitamin C (500 mg, b.i.d.) and vitamin E (200 IU, b.i.d.) for 30 days, in addition to lansoprazole (30 mg, b.i.d.), amoxicillin (1000 mg, b.i.d.), clarithromycin (500 mg, b.i.d.), and bismuth subcitrate (300 mg, q.i.d.) for 14 days. Total antioxidant capacity (TAC) was evaluated with a Randox kit. Success rate was calculated using both intention-to-treat (ITT) and per-protocol (PP) analyses.

RESULTS

One hundred and sixty patients were analyzed using ITT analysis. One hundred and fifty-three patients completed the study. In group A, H. pylori eradication was achieved in 48 (60%) of the 80 patients included in the ITT analysis, and in 48 (64%) of the 75 patients included in the PP analysis. In group B, H. pylori eradication was achieved in 73 (91.25%) of the 80 included in the ITT analysis and in 73 (93.5%) of the 78 patients included in the PP analysis. The eradication rate was significantly higher in group B than in group A (p < .005). TAC was at the lower limit of normal in both groups and the difference between them was not statistically significant (p > .05).

CONCLUSION

In group B, H. pylori eradication rate was 91.25%, which is higher than the ideal 80% eradication rate. The results of the present study show that adding the prescribed doses of vitamins E and C to antimicrobial therapy is effective in eradicating H. pylori infection.

Nutrition and gastric cancer risk: an update

Data from epidemiologic, experimental, and animal studies indicate that diet plays an important role in the etiology of gastric cancer. High intake of fresh fruits and vegetables, lycopene and lycopene-containing food products, and potentially vitamin C and selenium may reduce the risk for gastric cancer. Data also suggest that high intake of nitrosamines, processed meat products, salt and salted foods, and overweight and obesity are associated with increased risk for gastric cancer. However, current data provide little support for an association of beta-carotene, vitamin E, and alcohol consumption with risk for gastric cancer.

The Comparative Impact of Iron, the B-Complex Vitamins, Vitamins C and E, and Selenium on Diarrheal Pathogen Outcomes Relative to the Impact Produced by Vitamin A and Zinc

Micronutrient supplementation offers one of the most cost-effective means of improving the health and survival of children in developing countries. However, the effects of supplementation with single micronutrients on diarrhea are not always consistent, and supplementation with multi-micronutrient supplements can have negative effects. These inconsistencies may result from the failure to consider the diverse etiological agents that cause diarrhea and the unique effects each micronutrient has on the immune response to each of these agents. This review examines the separate effects that supplementation with the B-complex vitamins, vitamin C, vitamin E, selenium, and iron have on diarrheal disease-related outcomes. Supplementation with iron may increase the risk of infection by invasive diarrheal pathogens, while supplementation with the remaining micronutrients may reduce this risk. These differences may be due to distinct regulatory effects each micronutrient has on the pathogen-specific immune response, as well as on the virulence of specific pathogens. The findings of these studies suggest that micronutrient supplementation of children must take into account the pathogens prevalent within communities as reflected by their diarrheal disease burdens. The effectiveness of combining multiple micronutrients into one supplement must also be reconsidered.

Vitamin C supplementation does not protect L-gulono-gamma-lactone oxidase-deficient mice from Helicobacter pylori-induced gastritis and gastric premalignancy

In human studies, low vitamin C intake has been associated with more severe Helicobacter pylori gastritis and a higher incidence of gastric cancer. However, vitamin C supplementation has not been definitively shown to protect against gastric cancer. Using vitamin C-deficient B6.129P2-Gulo(tm1Umc/mmcd) (gulo(-/-)) mice lacking L-gulono-gamma-lactone oxidase, we compared gastric lesions and Th1 immune responses in H. pylori-infected gulo(-/-) mice supplemented with low (33 mg/L) or high (3,300 mg/L) vitamin C in drinking water for 16 or 32 weeks. Vitamin C levels in plasma and gastric tissue correlated with the vitamin C supplementation levels in gulo(-/-) mice. H. pylori infection resulted in comparable gastritis and premalignant lesions in wildtype C57BL/6 and gulo(-/-) mice supplemented with high vitamin C, but lesions were less severe in gulo(-/-) mice supplemented with low vitamin C at 32 weeks post infection. The reduced gastric lesions in infected gulo(-/-) mice supplemented with low vitamin C correlated with reduced Th1-associated IgG2c, gastric IFN-gamma and TNF-alpha mRNA and higher H. pylori colonization levels. These results in the H. pylori-infected gulo(-/-) mouse model suggest that although supplementation with a high level of vitamin C achieved physiologically normal vitamin C levels in plasma and gastric tissue, this dose of vitamin C did not protect gulo(-/-) mice from H. pylori-induced premalignant gastric lesions. In addition, less severe gastric lesions in H.pylori infected gulo(-/-) mice supplemented with low vitamin C correlated with an attenuated Th1 inflammatory response.

4-Vinyl-2,6-dimethoxyphenol (canolol) suppresses oxidative stress and gastric carcinogenesis in Helicobacter pylori-infected carcinogen-treated Mongolian gerbils

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.

Inhibitory effect of nordihydroguaiaretic acid, a plant lignan, on Helicobacter pylori-associated gastric carcinogenesis in Mongolian gerbils

Recent epidemiological studies have demonstrated that consumption of certain natural products can lower cancer risk in humans. For example, plant-derived lignans have been shown to exert chemopreventive effects against cancer in vitro and in vivo. In the present study, the effects of three such lignans, termed arctiin, arctigenin, and nordihydroguaiaretic acid (NDGA), on the proliferation of Helicobacter pylori and the prevention of H. pylori-associated gastric cancer were investigated in Mongolian gerbils. To examine the effects of arctigenin and NDGA on stomach carcinogenesis, specific pathogen-free male, 5-week-old gerbils were infected with H. pylori, administered 10 p.p.m. N-methyl-N-nitrosourea in their drinking water and fed diets containing various concentrations of lignans until they were killed after 52 weeks. At a dietary level of 0.25%, NDGA significantly decreased the incidence of gastric adenocarcinomas. Arctigenin, in contrast, failed to attenuate neoplasia at a level of 0.1%. Both NDGA and arctigenin significantly reduced serum 8-hydroxy-2'-deoxyguanosine levels at doses of 0.25 and 0.05% (NDGA), and 0.1% (arctigenin). Administration of 0.25% NDGA significantly suppressed the formation of intestinal metaplasia both in the antrum and the corpus. Although all three lignans dose-dependently inhibited the in vitro proliferation of H. pylori, there were no differences in the titers of anti-H. pylori antibodies or the amount of the H. pylori-specific urease A gene among all H. pylori-infected groups. These results suggest that NDGA might be effective for prevention of gastric carcinogenesis. The possible mechanisms appear to be related to inhibitory effects on progression of gastritis and antioxidative activity rather than direct antimicrobial influence.

Helicobacter pylori and gastric cancer

PURPOSE OF REVIEW

Although chronic Helicobacter pylori infection is the strongest known risk factor for development of gastric adenocarcinoma, only a small proportion of infected individuals will ever develop tumours. This article discusses various bacterial, host and environmental factors which may influence an individual's susceptibility.

RECENT FINDINGS

Recent research on bacterial virulence factors has focussed upon the cag pathogenicity island, particularly its roles in regulating epithelial growth and adhesion. Studies of host genetic factors have included several analyses of polymorphisms in inflammatory cytokines in human cohorts. Animal studies have recently clarified the roles of dysregulated epithelial apoptosis, proliferation and differentiation pathways during gastric carcinogenesis, and novel experiments involving H. felis infection of bone marrow transplanted irradiated mice have suggested that gastric cancer may originate from bone marrow-derived stem cells. Important roles for signalling between epithelial and mesenchymal cells, particularly myofibroblasts, are also emerging. Recent research on the importance of environmental factors has demonstrated how helminth coinfection may protect against atrophic gastritis and T helper type 1 responses.

SUMMARY

Complex interactions between several bacterial, host genetic and environmental factors determine whether H. pylori infected individuals develop gastric carcinoma. The importance of bone marrow stem cell engraftment during human gastric neoplasia is an area requiring urgent investigation.

Soluble triggering receptor expressed on myeloid cells (sTREM-1): a new mediator involved in the pathogenesis of peptic ulcer disease

OBJECTIVES

Triggering receptor expressed on myeloid cells (TREM-1) is a promoter of cytokine production triggered by microbial components. To investigate the significance of its soluble counterpart, sTREM-1, for the pathogenesis of peptic ulcer disease, sTREM-1 was compared with the proinflammatory mediators and the pathology score of gastritis.

METHODS

Forty patients with dyspepsia were enrolled: 20 with peptic ulcer and 20 controls without any macroscopic abnormalities. All patients were examined by endoscopy; gastric juice was aspirated and biopsy specimens were collected from the antrum and corpus of the stomach. sTREM-1 was estimated by a hand-made enzyme immunoassay. Interleukin-8 was estimated by enzyme-linked immunosorbent assay and lipid peroxidation, indexed by malondialdehyde, by the thiobarbituric assay, after passage through a high-performance liquid chromatography system.

RESULTS

The median (+/-SE) of sTREM-1 of controls and patients with ulcer was 3.91+/-0.57 and 44.27+/-241.55 RU, respectively (P=0.006). The median (+/-SE) of interleukin-8 of controls and patients with ulcer was 1802.97+/-122.10 and 2030.66+/-64.44 pg/ml, respectively (P=0.023). sTREM-1 was positively correlated with the density of neutrophil and mononuclear infiltration scores and the total Sydney score (P=0.029, 0.043 and 0.041, respectively). sTREM-1 was positively correlated with interleukin-8 (P=0.042).

CONCLUSIONS

sTREM-1 might be an independent factor involving with the peptic ulcerative inflammatory process that is positively correlated with histopathological abnormalities of gastritis.

Influence of vitamin E on gastric mucosal injury induced by Helicobacter pylori infection

We investigated the effect of vitamin E on gastric mucosal injury induced by Helicobacter pylori (H. pylori) infection. Male Mongolian gerbils were divided into 4 groups (normal group without H. pylori infection, vitamin E-deficient, -sufficient and -supplemented groups with H. pylori infection). Following oral inoculation with H. pylori (ATCC43504 2 x 10(8) CFU), animals were fed diets alpha-tocopherol 2 mg/100 g diet in the normal and vitamin E-sufficient groups and alpha-tocopherol 0.1 mg/100 g and 50 mg/100 g in the vitamin E-deficient and -supplemented groups, respectively, for 24 weeks. Chronic gastritis was detected in all gerbils inoculated H. pylori. Gastric ulcer was detected in 2 of 7 gerbils only in the vitamin E-deficient group. In the vitamin E-deficient group, myeloperoxidase activity and mouse keratinocyte derived chemokine (KC) in gastric mucosa was significantly higher than in the vitamin E supplemented group. Subsequently, in an in vitro study expression of CD11b/CD18 on neutrophils was enhanced by H. pylori water extract. This effect was suppressed in a dose dependent manner by the addition of alpha-tocopherol. These results suggest that vitamin E has a protective effect on gastric mucosal injury induced by H. pylori infection in gerbils, through the inhibition of accumulation of activated neutrophils.

Age-related changes in oxidative DNA damage and benzo(a)pyrene diolepoxide-I (BPDE-I)-DNA adduct levels in human stomach

This study was conducted in order to obtain information on the association between age and oxidative DNA damage and benzo[a]pyrene diolepoxide-I (BPDE-I)-DNA adduct levels in the stomach tissues of normal subjects (n = 113). Subjects ranged from 17 to 75 yr. The levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage, were measured by high-performance liquid chromatography-electrochemical detector (HPLC-ECD). BPDE-I-DNA adduct levels were quantitatively measured by enzyme-linked immunosorbent assay (ELISA) using the monoclonal antibody 8E11. Increase in 8-OHdG levels was observed in subjects from 31 to 60 yr of age. Higher levels of 8-OHdG were observed in the stomach tissues of those in the 51-60 yr old group. Although Helicobacter. Pylori-positive group subjects had higher 8-OHdG levels than those in the H. pylori-negative group, no age-related changes in 8-OHdG levels were observed in these groups. The levels of BPDE-I-DNA adduct also markedly increased with age. Higher levels of BPDE-I-DNA adduct were observed in subjects aged 61-70 yr, but this difference was not significant from other age groups. These results provide evidence that there is a progressive age-dependent accumulation of oxidative DNA damage and of BPDE-I-DNA adducts in human stomach tissues. It is possible that such damage contributes to the known increased incidence of gastric tumor with aging.