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

Association between dietary antioxidant index and risk of Helicobacter pylori infection among adults: a case-control study

Backgrounds and aims

One of the most important risk factors for Helicobacter pylori (H. pylori) infection is nutrition. Balanced diets with high antioxidant properties may have protective effects against the consequences of this infection. In the current study, we aimed to investigate the association between the dietary antioxidant index and the risk of H. pylori infection among adults.

Methods

In a case–control study the dietary intake of patients with H. pylori infection was compared with healthy subjects. The dietary antioxidant index (DAI) was calculated using dietary intakes derived from a validated food frequency questionnaire (FFQ). Demographic information was obtained by a related questionnaire and Physical Activity was measured by International Physical Activity Questionnaire (IPAQ) were used to obtain information. Using logistic regression models, we evaluated the association between the DAI and H. pylori infection risk. The significance level was determined as P < 0.05.

Results

Finally, dietary data of 148 cases and 302 controls (mean age: 38.72 ± 10.61 (were analyzed. The mean of total DAI was significantly higher in controls (7.67) when compared with H. pylori cases (3.57) (P < 0.001). After adjustment for covariates, participants with less than median DAI values had an increased risk of H. pylori onset (adjusted OR 1.08, 95% CI: 1.02–1.12, P < 0.001).

Conclusions

Appropriate intake of nutrient antioxidants may have a role in decreasing the likelihood of H. pylori infection risk.

Investigating Causal Associations of Diet-Derived Circulating Antioxidants with the Risk of Digestive System Cancers: A Mendelian Randomization Study

Molecular mechanisms and observational studies have found that diet-derived antioxidants are associated with digestive system cancers, whereas there is a lack of causal evidence from randomized clinical trials. In this study, we aimed to assess the causality of these associations through a Mendelian randomization (MR) study. Single nucleotide polymorphisms of diet-derived circulating antioxidants (i.e., α- and γ-tocopherol, ascorbate, retinol, β-carotene, lycopene, and urate), accessed by absolute levels and relative metabolite concentrations, were used as genetic instruments. Summary statistics for digestive system cancers were obtained from the UK Biobank and FinnGen studies. Two-sample MR analyses were performed in each of the two outcome databases, followed by a meta-analysis. The inverse-variance weighted MR was adopted as the primary analysis. Five additional MR methods (likelihood-based MR, MR-Egger, weighted median, penalized weighted median, and MR-PRESSO) and replicate MR analyses for outcomes from different sources were used as sensitivity analyses. Genetically determined antioxidants were not significantly associated with five digestive system cancers, after correcting for multiple tests. However, we found suggestive evidence that absolute ascorbate levels were negatively associated with colon cancer in UK Biobank-the odds ratio (OR) per unit increase in ascorbate was 0.774 (95% confidence interval [CI] 0.608-0.985, p = 0.037), which was consistent with the results in FinnGen, and the combined OR was 0.764 (95% CI 0.623-0.936, p = 0.010). Likewise, higher absolute retinol levels suggestively reduced the pancreatic cancer risk in FinnGen-the OR per 10% unit increase in ln-transformed retinol was 0.705 (95% CI 0.529-0.940, p = 0.017), which was consistent with the results in UK Biobank and the combined OR was 0.747 (95% CI, 0.584-0.955, p = 0.020). Sensitivity analyses verified the above suggestive evidence. Our findings suggest that higher levels of antioxidants are unlikely to be a causal protective factor for most digestive system cancers, except for the suggestive protective effects of ascorbate on colon cancer and of retinol on pancreatic cancer.

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.

The effect of antioxidants on Helicobacter pylori eradication: A systematic review with meta-analysis

BACKGROUND

The efficacy and safety of the addition of antioxidants to triple or quadruple therapy were unclear.

MATERIALS AND METHODS

This systematic review was performed in accordance with the PRISMA 2009 guidelines. A systematic search of PubMed, EMBASE, and the Cochrane Library databases was conducted to identify potentially relevant publications using the following keywords: ([Helicobacter pylori] or [H. pylori] or [Hp]) and ([antioxidant] or [vitamin] or [N-acetylcysteine] or [curcumin] or [cranberry]). The primary end-point of this study was to evaluate the efficacy of the addition of antioxidants to triple or quadruple therapy according to ITT and PP analysis. The second end-points were side effects and the comparative efficacy in terms of H. pylori eradication according to different antioxidant and antibiotic combinations.

RESULTS

We included 9 studies with 1260 participants. The total eradication rate of H. pylori in the group combining eradication therapy with antioxidants was not superior to that without antioxidants according to the ITT (pooled RR [95% CI] = 1.17 [0.99-1.38]; P = 0.07) and PP analysis (pooled RR [95% CI] = 1.15 [0.99-1.34; P = 0.07]. There were no differences regarding side effects between the two groups (pooled RR [95% CI], 1.36 [0.81-2.28]; P = 0.24). However, the eradication regimen with vitamin supplementation (1400 mg/day) showed a significant, superior efficacy in eradication relative to those without supplementation (pooled RR [95% CI] = 1.57 [1.35, 1.84]; P < 0.01). In particular, in the amoxicillin-clarithromycin-based subgroup, the crude H. pylori eradication rate determined by ITT analysis was 81.3% and 68.6% for eradication therapy with and without antioxidant supplementation, respectively, which was a statistically significant difference (pooled RR [95% CI] = 1.23 [1.02-1.49]; P = 0.03).

CONCLUSIONS

The addition of antioxidants (vitamin, N-acetylcysteine, curcumin, cranberry) to amoxicillin-clarithromycin-based therapy could improve the eradication rate, and vitamin supplementation might be effective at a high dosage. However, antioxidant supplements have no impact on improving side effects.

Vitamin E: a potential therapy for gastric mucosal injury

CONTEXT

Many scientific reports have shown the involvement of oxidative stress and inflammation as well as diminished gastroprotective substances in the pathogenesis of gastric lesions using various models. Therefore, treatment with antioxidants like tocopherol and tocotrienol may afford beneficial effects in attentuating the formation of the gastric lesions.

OBJECTIVE

The aim of this work was to summarize documented reports on the effects of vitamin E on various models of gastric lesion.

METHODS

A literature search was performed from databases in Medline (PubMed), Web of Science, ScienceDirect, and Googlescholar from June to December 2013.

RESULTS AND CONCLUSION

The potential roles of tocopherol and tocotrienol in modifying the effects of ulcerogenic agents are discussed in this review. The protective effects of the vitamin E might involve ameliorating oxidative stress and inflammation as well as restoration of endogenous gastroprotective substances. This vitamin has the potential to be used as a therapy for gastric mucosal injury.

Interaction between dietary factors and Helicobacter pylori infection in noncardia gastric cancer: a population-based case-control study in China

BACKGROUND

The aim of this study was to investigate the relationships among Helicobacter pylori, dietary factors, and the risk of noncardia gastric cancer in a hospital-based case-control study in China.

METHODS

A case-control study of noncardia gastric cancer was performed at 3 hospitals in Xi'an, China, between September 2008 and July 2010. Participants were 257 men and women with histologically diagnosed primary noncardia gastric cancer and 514 sex- and age-matched (± 5 years) control subjects selected from the communities where the cases were living when diagnosed. A questionnaire was used to obtain information regarding potential risk factors, including diet, and blood samples were obtained to examine H pylori infection status.

RESULTS

Positive H pylori status (odds ratio [OR], 3.2; 95% confidence interval [CI], 0.8-5.9) and high consumption of pickled foods (OR, 27.1; 95%, 8.7-79.1) appeared to increase the risk of noncardia gastric cancer, whereas high consumption of vegetables (OR, 0.3; 95% CI, 0.1-0.89), fruits (OR, 0.2; 95% CI, 0.09-0.81), and soya products (OR, 0.04; 95% CI, 0.01-0.3) appeared to decrease the risk. Consumption of meat, cereals, tubers, eggs, oils, nuts, fish, fresh fruit, and red meat was not clearly associated with risk. Effect modification was observed, such that a relatively high consumption of fruit and vegetables appeared to attenuate the association of H pylori with risk of noncardia gastric cancer (p < 0.05).

CONCLUSIONS

Our data suggest that noncardia gastric cancer is highly preventable through modifications in dietary habits. Given the prevalence of H pylori infection worldwide, information regarding potential interaction between H pylori and lifestyle factors in gastric cancer development, including the dietary factors examined in our study, may prove valuable in future efforts at prevention.

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.

Vitamin D and respiratory infection in adults

Vitamin D insufficiency is a global issue that has significant implications for health. The classical role of vitamin D in bone mineralisation is well known; vitamin D deficiency leads to rickets, osteomalacia or osteoporosis. The role of vitamin D in an immune system is less known. Vitamin D is not an actual vitamin but a secosteroid hormone produced in the skin from 7-dehydrocholesterol after exposure to sunlight UVB radiation. Nutrition and supplements are main sources of vitamin D in wintertime in northern countries as sunlight exposure is inadequate for the production. For activation vitamin D needs to be hydroxylated in liver to form 25-hydroxyvitamin D and in kidney to 1,25-dihydroxyvitamin D, the most active hormone in Ca absorption in the gut. For determination of vitamin D status serum 25-hydroxyvitamin D level, the major circulating form of the hormone is to be measured. Vitamin D regulates gene expression through binding with vitamin D receptors, which dimerises with retinoid X receptor. This complex binds to vitamin D-responsive elements inside the promoter regions of vitamin D-responsive genes. Vitamin D has a key role in innate immunity activation; the production of antimicrobial peptides (cathelicidin and defensins) following Toll-like receptor stimulation by pathogen lipopeptides is dependent on sufficient level of 25-hydroxyvitamin D. Clinically, there is evidence of the association of vitamin D insufficiency and respiratory tract infections. There is also some evidence of the prevention of infections by vitamin D supplementation. Randomised controlled trials are warranted to explore this preventive effect.

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.

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.

Helicobacter pylori cagA gene polymorphism affects the total antioxidant capacity of human saliva

BACKGROUND

We aimed to evaluate the total antioxidant capacity (TAC) of saliva in healthy Helicobacter pylori-positive and negative saliva individuals.

MATERIALS AND METHODS

A total of 102 human saliva samples were checked for the presence of H. pylori DNA (ureA and cagA gene fragments). TAC of saliva was estimated by ABTS radical cation (ABTS( +)) decolorization assay.

RESULTS

PCR analysis revealed that 36 subjects were ureA-/cagA-, 24 were ureA+/cagA- and 42 were ureA+/cagA+. Smoking habits had no evident effect on H. pylori infection. We found that TAC of the ureA-/cagA- material, after 10 seconds reaction reflecting fast-reacting antioxidants, was significantly higher than of ureA+/cagA- and ureA+/cagA+ samples (p < .01 and p < .001, respectively). Similar results were obtained for reaction time of 3 minutes measuring slow-reacting antioxidants (p < .001). We also estimated ureA+/cagA- and ureA+/cagA+ samples alone and reported a statistically significant decrease in the TAC(3 min) value of ureA+/cagA+ compared with ureA+/cagA- samples (p < .05).

CONCLUSIONS

Our data demonstrated that altered redox equilibrium may be associated with more frequent occurrence of H. pylori in the saliva samples.

A role for IL-18 in human neutrophil apoptosis

Decreased neutrophil apoptosis is associated with persistent inflammation, the severity of which correlates with serum IL-18 levels. IL-18 receptors as well as Toll-like receptors, including Toll-like receptor 4, a receptor for LPS, possess a highly conserved intracellular domain called "Toll-IL-1R domain" and activate overlapping signaling pathways. Here, we show that IL-18 modulates neutrophil apoptosis and compare its mechanism of action with LPS. We found that both IL-18 and LPS decreased neutrophil apoptosis in a similar dose- and time-dependent fashion. However, pretreatment with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 increased apoptosis more effectively in IL-18- than in LPS-stimulated cells, whereas the ERK inhibitor PD98059 had the same effect in both. In contrast, the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 had no influence on apoptosis at all. Neutrophils constitutively expressed mRNA for IL-18 receptor beta, but little or no receptor alpha, both of which increased during coculture with either IL-18 or LPS in a time- and dose-dependent manner. Of the Bcl-2 family, antiapoptotic A1/Bfl-1 tended to increase on IL-18 and LPS stimulation, but was further increased despite increased apoptosis in the presence of MAPK inhibitors. Thus, human neutrophils can express mRNA for IL-18 receptors alpha and beta, and IL-18, like LPS, inhibits neutrophil apoptosis by activating PI3K and ERK pathways but not p38MAPK. However, PI3K may play more important role(s) in IL-18- than in LPS-induced inhibition of apoptosis. Mitogen-activated protein kinases seem to mediate antiapoptotic signals through factors other than Bcl-2 gene family expression.