Low expression myeloperoxidase genotype negatively associated with Helicobacter pylori infection

Helicobacter pylori secretary Proteins-Induced oxidative stress and its role in NLRP3 inflammasome activation

Helicobacter pylori-associated stomach infection is a leading cause of gastric ulcer and related cancer. H. pylori modulates the functions of infiltrated immune cells to survive the killing by reactive oxygen and nitrogen species (ROS and RNS) produced by these cells. Uncontrolled immune responses further produce excess ROS and RNS which lead to mucosal damage. The persistent oxidative stress is a major cause of gastric cancer. H. pylori regulates nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs), nitric oxide synthase 2 (NOS2), and polyamines to control ROS and RNS release through lesser-known mechanisms. ROS and RNS produced by these pathways differentiate macrophages and T cells from protective to inflammatory phenotype. Pathogens-associated molecular patterns (PAMPs) induced ROS activates nuclear oligomerization domain (NOD), leucine rich repeats (LRR) and pyrin domain-containing protein 3 (NLRP3) inflammasome for the release of pro-inflammatory cytokines. This study evaluates the role of H. pylori secreted concentrated proteins (HPSCP) related oxidative stress role in NLRP3 inflammasome activation and macrophage differentiation. To perceive the role of ROS/RNS, THP-1 and AGS cells were treated with 10 μM diphenyleneiodonium (DPI), 50 μM salicyl hydroxamic acid (SHX), 5 μM Carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (FCCP), which are specific inhibitors of NADPH oxidase (NOX), Myeloperoxidase (MPO), and mitochondrial oxidative phosphorylation respectively. Cells were also treated with 10 μM of NOS2 inhibitor l-NMMA and 10 μM of N-acetyl cysteine (NAC), a free radical scavenger·H2O2 (100 μM) treated and untreated cells were used as positive controls and negative control respectively. The expression of gp91phox (NOX2), NOS2, NLRP3, CD86 and CD163 was analyzed through fluorescent microscopy. THP-1 macrophages growth was unaffected whereas the gastric epithelial AGS cells proliferated in response to higher concentration of HPSCP. ROS and myeloperoxidase (MPO) level increased in THP-1 cells and nitric oxide (NO) and lipid peroxidation significantly decreased in AGS cells. gp91phox expression was unchanged, whereas NOS2 and NLRP3 downregulated in response to HPSCP, but increased after inhibition of NO, ROS and MPO in THP-1 cells. HPSCP upregulated the expression of M1 and M2 macrophage markers, CD86 and CD163 respectively, which was decreased after the inhibition of ROS. This study concludes that there are multiple pathways which are generating ROS during H. pylori infection which further regulates other cellular processes. NO is closely associated with MPO and inhibition of NLRP3 inflammasome. The low levels of NO and MPO regulates gastrointestinal tract homeostasis and overcomes the inflammatory response of NLRP3. The ROS also plays crucial role in macrophage polarization hence alter the immune responses duing H. pylori pathogenesis.

Myeloperoxidase: Growing importance in cancer pathogenesis and potential drug target

Myeloperoxidase is a heme-peroxidase which makes up approximately 5% of the total dry cell weight of neutrophils where it is predominantly found in the primary (azurophilic) granules. Other cell types, such as monocytes and certain macrophage subpopulations also contain myeloperoxidase, but to a much lesser extent. Initially, the function of myeloperoxidase had been mainly associated with its ability as a catalyzer of reactive oxidants that help to clear pathogens. However, over the past years non-canonical functions of myeloperoxidase have been described both in health and disease. Attention has been specially focused on inflammatory diseases, in which an exacerbate infiltration of leukocytes can favor a poorly-controlled production and release of myeloperoxidase and its oxidants. There is compelling evidence that myeloperoxidase derived oxidants contribute to tissue damage and the development and propagation of acute and chronic vascular inflammation. Recently, neutrophils have attracted much attention within the large diversity of innate immune cells that are part of the tumor microenvironment. In particular, neutrophil-derived myeloperoxidase may play an important role in cancer development and progression. This review article aims to provide a comprehensive overview of the roles of myeloperoxidase in the development and progression of cancer. We propose future research approaches and explore prospects of inhibiting myeloperoxidase as a strategy to fight against cancer.

The other myeloperoxidase: Emerging functions

Myeloperoxidase (MPO) is a member of the mammalian peroxidase family. It is mainly expressed in neutrophils, monocytes and macrophages. As a catalyzer of reactive oxidative species and radical species formation, it contributes to neutrophil bactericidal activity. Nevertheless MPO invalidation does not seem to have major health consequences in affected individuals. This suggests that MPO might have alternative functions supporting its conservation during evolution. We will review the available data supporting these non-canonical functions in terms of tissue specific expression, function and enzymatic activity. Thus, we discuss its cell type specific expression. We review in between others its roles in angiogenesis, endothelial (dys-) function, immune reaction, and inflammation. We summarize its pathological actions in clinical conditions such as cardiovascular disease and cancer.

Aggressive periodontitis: An appraisal of systemic effects on its etiology-genetic aspect

Background:

Myeloperoxidase (MPO) is a lysosomal enzyme found in the azurophilic granules of polymorphonuclear leukocytes and is able to mediate inflammatory tissue destruction in aggressive and chronic periodontitis (CP). Human telomerase is a multi subunit ribonucleoprotein enzyme concerned with telomeric lengthening and homeostasis in man and has been found to be elevated in inflammatory conditions such as rheumatoid arthritis and periodontitis. The aim of this study was to explore in aggressive periodontitis (AP) subjects: (i) The role of MPO-463G/A gene polymorphism and (ii) the level of telomerase expression. These parameters have been compared with the subjects of CP and that of the healthy controls.

Materials and Methods:

A total of 45 subjects of the age group 20–50 years and free from any known systemic disease were included in the study. They were divided into three groups – Group I-periodontally healthy control (n = 15), Group II-CP (n = 15) and Group III-AP (n = 15). Peripheral blood samples and gingival tissue samples were collected for MPO gene polymorphism and telomerase expression, respectively, for detection by reverse transcriptase polymerase chain reaction.

Results:

The frequencies of AG and AA genotypes in the MPO gene polymorphism were more common in the AP subjects when compared to the controls. The m-RNA expression of human telomerase reverse transcriptase (hTERT) was undetectable in the gingival tissue of the control group. Its expression in AP subjects was significantly higher than that of CP group (83.61 ± 2.94 in CP and 104.27 ± 6.06 in AP) (P < 0.0001).

Conclusions:

Our data suggest that MPO-463G/A may be associated with increased risk of AP. The level of tissue hTERT was elevated in AP subjects as compared to CP and healthy control groups.

Susceptibility to Helicobacter pylori infection: results of an epidemiological investigation among gastric cancer patients

The aim of this study was to identify the clinical, demographic, lifestyle factors and selected genetic polymorphisms that affect the susceptibility towards Helicobacter pylori (H. pylori) infection in gastric cancer patients. Histological confirmed gastric adenocarcinoma cases that underwent curative gastrectomy between 2002 and 2012 were included. Gastric biopsy samples were obtained to determine the H. pylori status, and further cagA status and vacA m and s genotypes by polymerase chain reaction. Patients were interviewed with structured questionnaires, and blood samples were collected for EPHX1, GSTM1, GSTT1, IL1B, IL1-RN, MTHFR and p53 genotyping. Proportions were compared in univariate analysis, while the relation between putative risk factors and H. pylori status and genotype were measured using logistic regression analysis. One hundred forty-nine gastric cancer patients were included, of which 78.5% were H. pylori positive. Among positive patients 50% were cagA+, 72.5% vacA m1 and 80.7% vacA s1. The presence of cagA was less frequent among vacA m1 (p = 0.031) and vacA s1 (p = 0.052) subtypes. The presence of father history for any cancer was a significant risk factor for H. pylori infection [adjusted odds ratio (OR) = 8.18, 95% confidence interval (CI) 1.04-64.55]. EPHX1 exon 3 T > C (OR = 0.35, CI 95% 0.13-0.94), IL1B-511 T > C (OR = 0.38, CI 95% 0.15-0.97) and IL1-RN VNTR (OR = 0.19, CI 95% 0.06-0.58) polymorphisms were protective towards H. pylori infection in the univariate analysis. Wine consumption was associated with higher risk of carrying the H. pylori vacA m1 virulent subtype (p = 0.034). Lastly, cardiovascular diseases were less common among cagA positive subjects (p = 0.023). Father history of any cancer is a risk factor for H. pylori infection. Polymorphisms in IL1B-511, IL1-RN and EPHX1 exon 3 genes might be protective towards H. pylori infection.

No association between angiotensin I converting enzyme (ACE) I/D polymorphism and gastric cancer risk among Japanese

The angiotensin I-converting enzyme (ACE) is involved in cell proliferation, angiogenesis, inflammation, and tissue remodeling, all of which could play a role in carcinogenesis. The DD genotype of ACE I/D polymorphism with a higher ACE level than either ID or II genotypes was reported to increase the risk of several cancers. This is a case-control study examining the association between the polymorphism and gastric cancer risks among Japanese. Cases numbered 583 patients aged 27 to 80 years with gastric cancer diagnosed at the Aichi Cancer Center Hospital from 2001 to 2005. Controls were 1,742 sex and age frequency-matched cancer-free patients, who visited the same hospital during that same period. The ACE I/D polymorphism was genotyped using a polymerase chain reaction with confronting two-pair primers. The results showed that the age- and sex- adjusted ORs of gastric cancer were 0.95 (95% CI, 0.78-1.16) for ID, and 1.08 (95% CI, 0.80-1.46) for DD relative to II. Among the controls with H. pylori sero-positive or gastric atrophy (GA), the ORs of ID and DD relative to II were 1.20 (95% CI, 0.88-1.63) and 1.16 (95% CI, 0.73-1.84) for mild GA, and 1.22 (95% CI, 0.84-1.78) and 1.08 (95% CI, 0.61-1.89) for severe GA, respectively. In conclusion, there was no significant association of the ACE I/D polymorphism with the risk of gastric cancer. Among the controls, the polymorphism was not associated with the severity of GA.

Interleukin 1 beta (IL1B) promoter polymorphism and cancer risk: evidence from 47 published studies

Interleukin 1β (IL-1B) is a pro-inflammatory cytokine against infection, playing an important role in the pathogenesis of cancers. The -31T/C polymorphism of the interleukin 1β gene (IL1B) has been implicated in cancer risk through its influence on the IL1B transcription. However, results from studies are conflicting. To clarify the association, a meta-analysis was performed for 11 125 cases and 14 415 controls from 47 published case-control studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. No significant associations were observed for total cancer from all the comparisons. Through the stratified analyses, there was a statistically significant decreased risk of hepatocellular cancer in carriers of the C allele than non-carriers (CC versus TT: OR = 0.87, 95% CI: 0.77-0.98, P(heterogeneity) = 0.103; TC versus TT: OR = 0.77, 95% CI: 0.62-0.95, P(heterogeneity) = 0.734; TC + CC versus TT: OR = 0.74, 95% CI: 0.61-0.91, P(heterogeneity) = 0.472). Similarly, decreased risk was observed for gastric cancer of the C/C genotype compared with the T/T genotype (OR = 0.87, 95% CI: 0.77-0.98, P(heterogeneity) = 0.103). Using the recessive model, a significantly decreased risk was observed for gastric cancer (OR = 0.88, 95% CI: 0.80-0.97, P(heterogeneity) = 0.158), European population (OR = 0.84, 95% CI: 0.73-0.97, P(heterogeneity) = 0.070) and positive infection-matched studies (OR = 0.75, 95% CI: 0.60-0.94, P(heterogeneity) = 0.220); however, an increased risk was found for breast cancer (OR = 1.34, 95% CI: 1.18-1.61, P(heterogeneity) = 0.116). Although some modest bias could not be eliminated, this meta-analysis suggests that the IL1B -31C allele is a low-penetrance protective factor for the development of cancer, in particular for that associated with infection.

Genetic traits for the persistence of Helicobacter pylori infection

Helicobacter pylori infection elevates the risk of gastric diseases, including peptic ulcer and gastric cancer. Persistent infection is the first step to induce H. pylori-induced multistage diseases. Although the roles of genetic traits on persistent infection have not yet been elucidated, some individuals escape from persistent infection. Possible favorable conditions for H. pylori seem to be low acid secretion, reduced innate immune responses, and easier binding to gastric epithelial cells. IL-1β and TNF-α inhibit acid secretion. The genetic polymorphisms associated with both molecules have the potential to be the genetic traits underlying persistent infection. Functional polymorphisms associated with innate immune responses could also be involved with the genetic traits, but no polymorphisms with consistent associations have been identified so far. The polymorphisms associated with molecules for adhesion to epithelial cells are candidates of genetic traits, but more research is needed.

NQO1, MPO, and the risk of lung cancer: a HuGE review

The aim of this study is to summarize the available molecular epidemiologic studies of lung cancer and metabolic genes, such as NAD(P)H quinone reductase 1 (NQO1) and myeloperoxidase (MPO). NQO1 plays a dual role in the detoxification and activation of procarcinogens whereas MPO has Phase I activity by converting lipophilic carcinogens into hydrophilic forms. Variant genotypes of both NQO1 Pro187 Ser and MPO G-463A polymorphisms may be related to low enzyme activity. The Pro/Ser and Ser/Ser genotypes combined of NQO1 was significantly associated with decreased risk of lung cancer in Japanese [random effects odds ratio (OR) = 0.70, 95% confidence interval (CI) = 0.56-0.88] among whom the variant allele is common. The variant genotype of MPO was associated with decreased risk of lung cancer among Caucasians (random effects OR = 0.70, 95% CI = 0.47-1.04). Gene-environment interactions in both polymorphisms may be hampered by inaccurate categorization of tobacco exposure. Evidence on gene-gene interactions is extremely limited. As lung cancer is a multifactorial disease, an improved understanding of such interactions may help identify individuals at risk for developing lung cancer. Such a study should include larger sample size and other polymorphisms in the metabolism of tobacco-derived carcinogens and address interactions with smoking status. The effects of polymorphisms are best represented by their haplotypes. In future studies on lung cancer, the development of haplotype-based approaches will facilitate the evaluation of haplotypic effects, either for selected polymorphisms physically close to each other or for multiple genes within the same drug-metabolism pathway.

Effects of the myeloperoxidase 463 gene polymorphisms on development of atrophy in H pylori infected or noninfected gastroduodenal disease

AIM: To investigate the relationship between myelo-peroxidase polymorphisms as a host-related factor and atrophy caused by H pylori.

METHODS: Our study enrolled 77 patients. Biopsy materials obtained during gastrointestinal endoscopies were evaluated for the presence of H pylori. Polymerase chain reaction-restriction fragment length polymorphism assay was used to characterize myeloperoxidase genotypes.

RESULTS: Forty four patients (57.1%) were Hp (+) and 33 (42.9%) were Hp (-). Sixty six (85.7%) had GG genotype, 10 (12.9%) had GA genotype and 1 (1.29%) had AA genotype. The change in atrophy in relation to neutrophil infiltration was significant in Hp (+) patients (P = 0.0001). The change in atrophy in relation to neutrophil infiltration in patients with GG genotype was significant (P = 0.002). However, the change in atrophy in relation to neutrophil infiltration was not significiant in patients with Hp (+) GG genotype (r = 0.066, P = 0.63).

CONCLUSION: Myeloperoxidase genotype is critical for development of atrophy in relation to the severity of inflammation. However, it is interesting to note that, H pylori does not show any additive effect on development of atrophy.

Genetic factors involved in the development of Helicobacter pylori-related gastric cancer

Developmental process to gastric cancer by Helicobacter pylori infection consists of three steps: (1) H. pylori infection; (2) gastric atrophy development; and (3) carcinogenesis. In each step, genetic traits may influence the process, interacting with lifestyle. In the step of H. pylori infection, two lines of genetic polymorphisms were assumed: one influencing gastric acid inhibition interacting with smoking, and the other concerning innate immune response attenuation. The former includes functional polymorphisms of IL-1B (C-31T or tightly linked T-511C), and TNF-A (T-1031C and C-857T), and the latter possibly includes NQO1 C609T. In the step to gastric atrophy, polymorphisms pertaining to the signal transduction from cytotoxin-associated gene A (PTPN11 A/G at intron 3) and to T-cell responses (IL-2 T-330G and IL-13 C-1111T) were hypothesized. There are a limited number of epidemiological genotype studies on the final step of literal carcinogenesis, potentially interacting with smoking, a low vegetable and fruit intake, and salty foods, the well-documented risk factors. In past case-control studies on the associations between genotype and gastric cancer risk, the cases consisted of H. pylori-related and unrelated gastric cancer patients and the controls consisted of individuals including the uninfected (H. pylori unexposed and exposed) and the infected with and without gastric atrophy. Accordingly, it was not clear whether the observed risk was for H. pylori-related or -unrelated gastric cancer, nor which step was involved in the observed associations even when nearly all cases were H. pylori-related. In order to elucidate the genetic traits of H. pylori-related gastric cancer, stepwise evaluation will be required.

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori infection

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

Myeloperoxidase −463G>A polymorphism and risk of primary lung cancer in a Korean population

BACKGROUND

Myeloperoxidase (MPO) contributes to pulmonary carcinogenesis through activation of a wide range of tobacco smoke procarcinogens, including benzo[a]pyrene and aromatic amines. A -463G>A polymorphism in the promoter region of the MPO gene has been shown to reduce MPO expression and activity. It is therefore possible that carriers of the -463A allele may be at decreased risk of lung cancer. To test this hypothesis we have investigated the association between the -463G>A polymorphism of MPO gene and the risk of lung cancer in a Korean population.

METHODS

The MPO genotype was determined in 432 lung cancer patients and 432 healthy controls that were frequency-matched for age and gender.

RESULTS

In the current study, the risk estimate for lung cancer of the combined -463 AA+GA genotype was not significantly different from that of the -463GG genotype (adjusted OR=1.03, 95% CI=0.72-1.47). In addition, we observed no evidence of effect modification by age, gender, smoking history or tumor histology.

CONCLUSIONS

These results suggest that the MPO -463G>A polymorphism does not significantly affect the susceptibility to lung cancer in Koreans.

Increased risk of colorectal cancer due to interactions between meat consumption and the CD36 gene A52C polymorphism among Japanese

A previous study showed expression of CD36, recently reported to play important roles in metabolism of oxidized low-density lipoprotein and long-chain fatty acids and to be positively correlated with colon cancer prognosis. To examine relationships between colorectal cancer and the CD36 gene A52C polymorphism according to meat consumption as a surrogate for saturated fatty acid intake, we conducted the present hospital-based, case-control study of 128 cases and 238 non-cancer controls. Consumption of meat and vegetables/fruit was divided into three (low, moderate, and high) and two (low and high) groups, respectively. Regarding the risk of colorectal cancer on cross-classifying subjects for the CD36 genotype and meat consumption, the odds ratio (OR) for the C/C genotype with moderate meat consumption relative to the A/A genotype with low meat consumption was 8.30 (95% confidence interval, CI=2.15-32.00). None of individuals with the C/C genotype was in the high meat consumption group. In the low vegetables/fruit consumption group, the OR for the C/C genotype relative to the A/A genotype was 3.03 (95% CI=1.12-7.90). Our findings suggest that interactions between moderate-high meat consumption and the CD36 gene A52C polymorphism may increase the risk of colorectal cancer.

Biosynthesis, processing, and sorting of human myeloperoxidase

Exclusively synthesized by normal neutrophil and monocyte precursor cells, myeloperoxidase (MPO) functions not only in host defense by mediating efficient microbial killing but also can contribute to progressive tissue damage in chronic inflammatory states such as atherosclerosis. The biosynthetic precursor, apoproMPO, is processed slowly in the ER, undergoing cotranslational N-glycosylation, transient interactions with the molecular chaperones calreticulin and calnexin, and heme incorporation to generate enzymatically active proMPO that is competent for export into the Golgi. After exiting the Golgi the propeptide is removed prior to final proteolytic processing in azurophil granules, resulting in formation of a symmetric MPO homodimer linked by a disulfide bond. Some proMPO escapes granule targeting and becomes constitutively secreted to the extracellular environment. Although the precise mechanism is unknown, the pro-segment is required for normal processing and targeting, as propeptide-deleted MPO precursor is either degraded or constitutively secreted. Characterizing the molecular consequences of naturally occurring mutations that cause inherited MPO deficiency provides unique insight into the structural determinants of MPO involved in biosynthesis, processing and targeting.

Environmental Factors in Helicobacter pylori-Related Gastric Precancerous Lesions in Venezuela

Although Helicobacter pylori (HP) infection has been acknowledged to play an etiological role in gastric carcinogenesis, its relatively weak association particularly in developing countries suggests critical roles of cofactors. Among a population with an extremely high prevalence of HP infection (≈95%) in Venezuela, we examined the relationship of household characteristics, smoking, alcohol drinking, dietary consumption, and plasma nutrient levels with the prevalence of three different stages of gastric precancerous lesions, chronic atrophic gastritis (AG; n = 337), intestinal metaplasia (IM; n = 551), and dysplasia (n = 157), in comparison with those without any of these lesions (n = 1154). Length of refrigerator use was marginally inversely associated with the prevalence of the precursor lesions studied. The association was most pronounced for AG followed by dysplasia. On the other hand, smoking status was a significant predictor for IM and dysplasia. Those smoking ≥10 cigarettes/day had 1.8-fold risk of IM and 3.6-fold risk of dysplasia compared with never smokers. There were no associations with alcohol consumption. When six food groups known to be associated with stomach cancer risk in Venezuela were tested, the prevalence of these lesions progressively increased with increasing starchy vegetable consumption and decreasing fresh fruit/fruit juice consumption. The association with fruits was more evident for dysplasia and AG and that with starchy vegetables for IM and AG. However, there were no inverse associations with plasma antioxidant vitamins. These findings offer important public health implications in preventing progression of HP-associated gastric precancerous lesions in high-risk populations.

High anti-Helicobacter pylori antibody seropositivity associated with the combination of IL-8-251TT and IL-10-819TT genotypes

BACKGROUND

Helicobacter pylori induces inflammation of gastric mucosa regulated by several interleukins. This study examined associations between anti-Helicobacter pylori immunoglobulin G antibody seropositivity and functional polymorphisms of interleukin-8 T-251 A and interleukin-10 T-819C.

MATERIALS AND METHODS

The subjects were 454 health check-up examinees (126 males and 328 females) without a history of cancer, aged 35-85 years, residing in Nagoya, Japan. After written informed consent was obtained individually, residual blood was anonymously applied for anti-Helicobacter pylori immunoglobulin G antibody testing and genotyping by the polymerase chain reaction with confronting two-pair primers.

RESULTS

The genotype frequency of interleukin-8 T-251 A was 52.2% for TT, 39.5% for TA, and 8.3% for AA, and that of interleukin-10 T-819C was 49.5% for TT, 39.9% for TC and 10.6% for CC. Although the differences in the positive rates among the genotypes were not marked, 115 individuals with interleukin-8-251TT (low expression genotype) and interleukin-10-819TT (high expression genotype) had a higher rate (63.5%) than the others (52.0%). Relative to the combination of interleukin-8-251TT and interleukin-10-819TT, the sex-age-adjusted odds ratio for those with the other combinations was 0.62 (95% confidence interval, 0.39-0.98). The adjusted odds ratio among 65 current smokers was 0.13 (0.03-0.61).

CONCLUSIONS

The observed association suggests that individuals with interleukin-8-251TT and interleukin-10-819TT, a combination presumably causing mild inflammation, have a higher probability of the continuing Helicobacter pylori infection, especially among current smokers.

Myeloperoxidase (MPO) genotype and lung cancer histologic types: the MPO -463 A allele is associated with reduced risk for small cell lung cancer in smokers

MPO participates in the metabolic activation of tobacco carcinogens such as PAHs. A frequent MPO -463 G-->A polymorphism in the promoter region reduces MPO transcription and has been correlated with >4-fold lower benzo[a]pyrene-DNA adduct levels in the skin of coal tar-treated patients. Four of 7 case-control studies found significantly reduced lung cancer risk associated with the A allele. Due to their different etiologies, we examined whether the MPO genotype affects histologic lung cancer types differentially. A case-control study was conducted in 625 ever-smoking lung cancer patients, including 228 adenocarcinomas, 224 SCCs, 135 SCLCs and 340 ever-smoking hospital controls. MPO genotyping was performed by capillary PCR followed by fluorescence-based melting curve analysis. Combining the MPO -463 (G/A+A/A) genotypes, a protective effect approaching significance (OR = 0.75, 95% CI 0.55-1.01) was observed when comparing all lung cancer cases to controls. Among histologic types of lung cancer, a weak protective effect was found for both adenocarcinoma (OR = 0.81, CI 0.55-1.19) and SCC (OR = 0.82, CI 0.56-1.21); a stronger and significant effect was found for SCLC (OR = 0.58, CI 0.36-0.95; p = 0.029). Our results also suggest that the MPO genotype varies among inflammatory nonmalignant lung diseases. In conclusion, our results emphasize the need for a separate analysis of lung cancer histologic types and an adjustment for inflammatory nonmalignant lung diseases in future MPO-related studies. We confirm that the MPO -463 A variant affords a protective effect against lung cancer risk in smokers, which was strongest for SCLC patients.

A genotypic association implicates myeloperoxidase in the progression of hepatic fibrosis in chronic hepatitis C virus infection

The hepatitis C virus (HCV) is a major cause of liver disease and the complications of cirrhosis. Liver biopsies, performed prior to the development of liver cirrhosis, characteristically show an inflammatory cell infiltrate with varying degrees of fibrosis. Precisely how HCV infection induces hepatic fibrogenesis is unknown. Recent studies suggest the release of oxidants, cytokines and proteases from the host immune system are key to the development of fibrosis. Macrophages and neutrophils, cells heavily represented in the inflammatory cell response, contain the oxidant generating enzyme myeloperoxidase (MPO). Cellular levels of MPO can be influenced by a functional promotor polymorphism, -463G/A, which precedes the MPO gene. We examined the relationship between this MPO promotor genotype and the degree of fibrosis in 166 patients with chronic HCV infection. All patients had previously participated in clinical drug trials for the treatment of chronic HCV infection. The MPO genotype was determined from cryo-preserved lymphocytes obtained from patients prior to treatment. The degree of fibrosis was estimated from liver biopsy specimens obtained prior to treatment. We found that patients with the MPO GA/AA genotype were more likely to have advanced fibrosis scores compared with those with the GG genotype: Of the patients with GG genotype, 78% (79 of 102 cases) had lower Knodell Fibrosis scores of 0 or 1, compared to 56% (37 of 64 cases) of patients with GA/AA genotype (P < 0.05). The mechanism(s) by which MPO contributes to fibrosis progression remains to be determined.

-463 G/A myeloperoxidase promoter polymorphism is associated with clinical manifestations and the course of disease in MPO-ANCA-associated vasculitis

Wegener's granulomatosis, microscopic polyangiitis, and Churg Strauss syndrome are forms of systemic vasculitides in which neutrophils and monocyte macrophages infiltrate the walls of small blood vessels, leading to destruction and occlusion. These diseases are associated with autoantibodies directed against granular components of neutrophils and monocytes, i.e., antineutrophil cytoplasmic antibodies (ANCA). The most common target antigens of ANCA in these vasculitides are myeloperoxidase (MPO) and proteinase 3 (PR3). ANCA-stimulated neutrophils injure endothelial cells, a process that is dependent upon the production of reactive oxygen radicals and the release of granular components such as MPO and PR3. Here we investigate whether a common functional MPO promoter polymorphism (-463 G/A) is associated with increased incidence and clinical aspects of ANCA-associated small vessel vasculitis. Genotyping was carried out for 142 patients with ANCA-associated small vessel vasculitis and 129 ethnically matched controls. The GG genotype was found to be associated with an increased risk for MPO-ANCA-associated vasculitis in females (86% GG, P = 0.045), but not males (64% GG, P = 1.0). Interestingly, the MPO A allele is associated with an increased incidence of relapses (P = 0.012) and an earlier age at diagnosis (P = 0.03) of MPO-ANCA-associated vasculitis. Both these associations are specific for MPO-ANCA and are not observed in patients with PR3-ANCA-associated vasculitis. These findings suggest that MPO expression levels influence the disease course of MPO-ANCA-associated vasculitis and further support the view that genetic factors are involved in the pathophysiology of this autoimmune disease.

Gender and smoking-related risk reduction of periodontal disease with variant myeloperoxidase alleles

Myeloperoxidase (MPO) is an oxidative enzyme expressed in polymorphonuclear leukocytes. It is involved in the defence against periodontal bacteria, and is also able to mediate inflammatory tissue destruction in periodontal disease. A G/A polymorphism in the promoter region of the MPO gene at position -463 has been assumed to exert profound effects on the expression of the enzyme. It is the aim of this study to evaluate whether this polymorphism may influence the risk of periodontal diseases. A total of 3148 subjects were randomly selected from the general population in the SHIP study (Study of Health in Pomerania). Periodontal status, health-related and socio-economic items were assessed. All subjects aged 40-60 years (n = 1103) were included in this study, and 1083 genotyped for the MPO -463 G/A polymorphism by PCR and RFLP methods. The genotype frequencies determined were homozygous wild type G/G 65.9% (95% CI 63.5-68.6), heterozygous A/G 31.4% (28.8-34.4), and homozygous variant A/A 2.7% (2.0-3.8). Only female subjects have a significantly reduced risk of severe periodontal disease when bearing the variant genotypes A/G or A/A. In female subjects the reduction in periodontal risk was significant for non-smokers (OR = 0.48; 95% CI 0.23-0.96); the smoke-related increase in risk was also reduced (OR = 0.50; 95% CI 0.22-1.10). When adjusted for age, smoking, and education the odds ratios were calculated as 0.52 (P = 0.01) and 0.97 (P = 0.90) for female and male subjects, respectively. The results of this study confirm the assumption that the MPO -463A allele variants are protective in the pathogenesis of periodontal diseases. This holds true only with women but not with men. The results are discussed with respect to the known influences of sexual hormones on MPO activity.

Growing significance of myeloperoxidase in non-infectious diseases

Myeloperoxidase (MPO) is a glycoprotein released by activated polymorphonuclear neutrophils, which takes part in the defense of the organism through production of hypochlorous acid (HOCl), a potent oxidant. Since the discovery of MPO deficiency, initially regarded as rare and restricted to patients suffering from severe infections, MPO has attracted clinical attention. The development of new technologies allowing screening for this defect has permitted new advances in the comprehension of underlying mechanisms. Apart from its implications for host defense, the expression of MPO restricted to myeloid precursors makes MPO mRNA a good marker of acute myeloid leukemia. In addition, during the last few years, involvement of MPO has been described in numerous diseases such as atherosclerosis, lung cancer, Alzheimer's disease and multiple sclerosis. Both strong oxidative activity and MPO genetic polymorphism have been involved. This review summarizes the broad range of diseases involving MPO and points out the possible use of this protein as a new clinical marker and a future therapeutic target.

Helicobacter pylori seropositivity among 963 Japanese Brazilians according to sex, age, generation, and lifestyle factors

Seropositivity of anti-Helicobacter pylori antibody (HP + ) was examined among Japanese Brazilians. The study was announced through 18 Japanese community culture associations in São Paulo, Curitiba, Mogi das Cruzes, and Mirandopolis in 2001. Among 969 participants, 963 individuals aged 33 - 69 years were analyzed. The overall HP + % was 48.1% (95% confidence interval, 44.9 - 51.3%). There was no difference in HP + % between 399 males and 564 females (49.6% and 47.0%, respectively). The HP + % increased with age; 35.3% for those aged 33 - 39 years, 46.2% for those aged 40 - 49 years, 46.5% for those aged 50 - 59 years, and 56.9% for those aged 60 - 69 years, but no differences were observed among the generations (Issei, Nisei, and Sansei) for each 10-year age group. Mogi das Cruzes, a rural area, showed a higher HP + %. Length of education was inversely associated with the positivity; the odds ratio (OR) relative to those with eight years or less of schooling was 0.61 (0.42 - 0.89) for those with 12 years or more. The associations with smoking and alcohol drinking were not significant. Fruit intake was associated with the HP + %; the OR relative to everyday intake was 1.38 (1.05 - 1.83) for less frequent intake, while intake frequencies of green tea, miso soup, and pickled vegetables (tsukemono) were not. Multivariate analysis including sex, 10-year age group, residence, education, and fruit intake showed that all factors except sex were significant. This is the largest study of HP infection among Japanese Brazilians, and the results indicated a similar pattern of age-specific infection rate to that for Japanese in Japan.