A review of the postulated mechanisms concerning the association of Helicobacter pylori with ischemic heart disease

Role of Helicobacter pylori Infection in Pathogenesis, Evolution, and Complication of Atherosclerotic Plaque

The therapeutic management of atherosclerosis focuses almost exclusively on the reduction of plasma cholesterol levels. An important role in the genesis and evolution of atherosclerosis is played by chronic inflammation in promoting thrombosis phenomena after atheroma rupture. This review aims to take stock of the knowledge so far accumulated on the role of endemic HP infection in atherosclerosis. The studies produced so far have demonstrated a causal relationship between Helicobacter pylori (HP) and CVD. In a previous study, we demonstrated in HP-positive patients that thrombin and plasma fragment 1 + 2 production was proportionally related to tumor necrosis factor-alpha levels and that eradication of the infection resulted in a reduction of inflammation. At the end of our review, we can state that HP slightly affects the risk of CVD, particularly if the infection is associated with cytotoxic damage, and HP screening could have a clinically significant role in patients with a high risk of CVD. Considering the high prevalence of HP infection, an infection screening could be of great clinical utility in patients at high risk of CVD.

Helicobacter pylori infection and rheumatoid arthritis as risk enhancers' factors for atherosclerotic cardiovascular diseases

BACKGROUND

In addition to established risk factors for atherosclerotic cardiovascular diseases (aCVDs), infections and autoimmune diseases, such as Helicobacter pylori (H. pylori) and rheumatoid arthritis (RA), have been reported as risk-enhancer factors. In this retrospective single-center, case-control study, the relative weight of RA and H. pylori infection on aCVD was evaluated in a cohort of patients from Northern Sardinia, Italy, where both conditions are frequent.

MATERIALS AND METHODS

Data were retrieved from records of subjects undergoing upper endoscopy and screened for H. pylori infection by at least four biopsies. The presence of H. pylori and chronic-active gastritis were labeled as a current infection or a long-lasting infection (LLHp) when atrophy and/or metaplasia and/or dysplasia were detected in at least one gastric specimen. Diagnosis of aCVD and RA was made by the cardiologist and the rheumatologist, respectively, according to guidelines. Odd ratios (ORs) for aCVD were evaluated, adjusting for age, sex, excess weight, cigarette smoking, blood hypertension, dyslipidemia, diabetes, H. pylori status, and RA.

RESULTS

Among 4821 records (mean age 52.1 ± 16.7 years; 66.0% female), H. pylori infection was detected in 2262 patients, and more specifically, a LLHp infection was present in 1043 (21.6%). Three-hundred-three (6.3%) patients were diagnosed with aCVD, and 208 (4.3%) with RA. In patients with aCVD (cases), the LLHp infection (33.3% vs. 20.8%, p < 0.0001) and RA (12.2% vs. 3.8%, p < 0.0001) were more frequent in cases compared with controls (patients without aCVD). After adjusting for traditional aCVD risk factors, ORs significantly increased for LLHp infection (1.57; 95% CI 1.20-2.06) and RA (2.63; 95% CI 1.72-4.02). Interestingly, the LLHp infection in patients with RA showed an overall addictive effect on the risk for aCVD (7.89; 95% CI 4.29-14.53).

CONCLUSIONS

According to our findings, patients with RA should benefit from being screened and eventually treated for H. pylori infection.

Causality of anti-Helicobacter pylori IgG levels on myocardial infarction and potential pathogenesis: a Mendelian randomization study

Background

Previous observational studies have shown that a potential relationship between anti-Helicobacter pylori (H. pylori) IgG levels and Myocardial Infarction (MI). Nevertheless, the evidence for the causal inferences remains disputable. To further clarify the relationship between anti-H. pylori IgG levels and MI and explore its pathogenesis, we conducted a Mendelian randomization (MR) analysis.

Methods

In this study, we used two-sample Mendelian Randomization (MR) to assess the causality of anti-H. pylori IgG levels on MI and potential pathogenesis, 12 single nucleotide polymorphisms (SNPs) related to anti-H. pylori IgG levels were obtained from the European Bioinformatics Institute (EBI). Summary data from a large-scale GWAS meta-analysis of MI was utilized as the outcome dataset. Summary data of mediators was obtained from the FinnGen database, the UK Biobank, the EBI database, MRC-IEU database, the International Consortium of Blood Pressure, the Consortium of Within family GWAS. Inverse variance weighted (IVW) analysis under the fixed effect model was identified as our main method. To ensure the reliability of the findings, many sensitivity analyses were performed.

Results

Our study revealed that increases of anti-H. pylori IgG levels were significantly related to an increased risk of MI (OR, 1.104; 95% CI,1.042-1.169; p = 7.084 × 10-4) and decreases in HDL cholesterol levels (β, -0.016; 95% CI, -0.026 to -0.006; p = 2.02 × 10-3). In addition, there was no heterogeneity or pleiotropy in our findings.

Conclusion

This two-sample MR analysis revealed the causality of anti-H. pylori IgG levels on MI, which might be explained by lower HDL cholesterol levels. Further research is needed to clarify the results.

Relationship between active Helicobacter pylori infection and risk factors of cardiovascular diseases, a cross-sectional hospital-based study in a Sub-Saharan setting

Background

Chronic inflammation has been reported as one of the novel coronary heart disease (CHD) risk factors. Knowing that Helicobacter pylori (H. pylori) provokes a local inflammation, the relationship between H. pylori infection and cardiovascular disease (CVD) has received considerable attention. However, the attempt to demonstrate the association between H. pylori and specific cardiovascular disease risk factors is always a challenging issue due to the conflicting reports in the literatures.

Methods

We performed a cross-sectional study of 363 consecutive dyspeptic subjects in three reference health facilities in Cameroon from October 2020 to October 2021. Each participation gave a written consent and the study was approved by the local Ethical Committee. Check-up for cardiovascular disease (CVD) risk factors such as dyslipidemia-related parameters, obesity-related parameter, high blood pressure as well as H. pylori detection was done for each participant. Data was analyzed using SSPS statistical package.

Results

Helicobacter pylori infection was significantly associated with higher total cholesterol level (OR: 2.3324, p = 0.0002) and higher LDL cholesterol level (OR: 2.3096, p = 0.0006). The crude OR of H. pylori status on the prevalence of high body mass index (BMI) was 1.0813 (p = 0.7300) and the adjusted OR for confounding factors was 1.1785 (p = 0.5095). The strength of the association between H. pylori infection and blood pressure, shows an OR of 1.3807 (p = 0.2991), 1.0060 (p = 0.9855) and 1.4646 (p = 0.2694) for diastolic pressure, hypertension and high heart rate respectively, while that of systolic pressure was 0.8135 (p = 0.4952). H. pylori infection is associated with dyslipidemia in our milieu.

Seroprevalence and Determinants of Helicobacter pylori Infection in the Hispanic Community Health Study/Study of Latinos

BACKGROUND & AIMS

Helicobacter pylori infection is the primary known risk factor for gastric cancer. Despite the global decline in H. pylori prevalence, this infection remains a major public health concern in developing areas, including Latin America. Our study aimed to determine H. pylori seroprevalence and identified its determinants among Hispanics/Latinos living in the United States (U.S.).

METHODS

The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) is a population-based sample of self-identified Hispanics/Latinos (n = 16,144) in four U.S. communities, aged 18 to 74 years, recruited from randomly selected households using a stratified two-stage area probability sample design based on sampling households within sampled census block groups weighted for differential response rates. Anti-H. pylori immunoglobulin G antibodies were measured by an enzyme-linked immunosorbent assay using plasma samples. We calculated adjusted seroprevalence (i.e., predicted margins) from multivariable logistic regression models.

RESULTS

The overall weighted H. pylori seroprevalence was 57% among HCHS/SOL participants, with 38% and 62% seropositivity among U.S.-born and non-U.S.-born individuals, respectively. Age-adjusted prevalence varied by self-reported Hispanic/Latino background, ranging from 47% in Puerto Rican to 72% in Central American backgrounds. Adjusted H. pylori seroprevalence was higher in the following groups: older age, male sex, lower education, non-U.S. born status, smoking, greater number of missing teeth, fewer doctor visits, lower ferritin level, and hepatitis A seropositivity.

CONCLUSIONS

H. pylori seroprevalence in Hispanics/Latinos remains high and differed significantly by Hispanic/Latino background. H. pylori seropositivity is strongly associated with poor socioeconomic conditions. These findings highlight the ongoing importance of this bacterial infection in the U.S.

Association of Helicobacter pylori Infection With Carotid Atherosclerosis in a Northern Chinese Population: A Cross-Sectional Study

Numerous studies have shown that Helicobacter pylori (HP) infection may be involved in the development of carotid atherosclerosis (CAS), but this conclusion is still controversial. The aim of this study was to explore whether there is a positive association between HP infection and CAS occurrence. We collected data on demographic characteristics, lifestyle, and disease history of the participants by questionnaire. We obtained clinical anthropometric data and blood samples of the participants from clinical examinations and laboratory work. The 13C urea breath test (13C-UBT) was performed to assess the HP infection status, and carotid ultrasonography was used to diagnose the CAS and plaque types. Univariate analysis and multivariate logistic regression were used to identify the relationship between HP infection and CAS. A total of 1,424 participants were recruited for this study. A total of 740 HP-positive individuals and 684 HP-negative individuals were identified, and 345 participants were diagnosed with CAS. The prevalence of CAS was higher in the HP-positive group (26.4%) than in the HP-negative group (21.7%) (P &lt; 0.05). A significantly higher prevalence of carotid intima-media thickening, carotid plaque, and carotid stenosis was identified in the HP-positive group than in the HP-negative group (P &lt; 0.05). There was no significant difference in the detection rate of unstable plaques between the HP-positive and HP-negative groups (P &gt; 0.05). In multivariate models adjusted for covariates, HP infection showed a positive association with CAS, independent of other risk factors (ORs range: 1.283–1.333, P &lt; 0.05). HP infection independently accounted for approximately 5% of the CAS risk in the absence of other cardiovascular risk factors. A positive association between HP infection and CAS was demonstrated in this study. HP infection might be an independent risk factor for CAS. Although the effect of HP infection on CAS observed in our study was less than that of traditional risk factors, we believe that this is an indispensable advance in the etiological study of CAS. These results imply that the microbial population might play an essential role in CAS, which provides a new perspective for the primary prevention of CAS.

Persistent Helicobacter pylori infection for more than 3 years leads to elevated serum homocysteine concentration: A retrospective cohort study based on a healthy Chinese population

BACKGROUND AND AIM

The relationship between the Helicobacter pylori (H. pylori) infection and homocysteine is unclear. We evaluated the effect of H. pylori on serum homocysteine in a healthy Chinese population.

METHODS

A total of 21 184 individuals aged over 18 years underwent ¹³ C/¹⁴ C urease breath test (¹³ C/¹⁴ C-UBT) and blood tests and 5042 individuals with follow-up intervals greater than 6 months. Homocysteine levels are classified according to the Chinese expert consensus.

RESULTS

The rates of H. pylori infection of normal level, mild level, moderate level, and severe level were 40.9%, 43.8%, 45.8%, and 46.6%, respectively (P = 0.000). H. pylori infection increased the risk of higher homocysteine concentration (OR = 1.406, P = 0.000). In the case-control study, the rates of persistent negative, new infection, persistent infection, and eradication infection were 43.6%, 11.2%, 22.9%, and 22.3%, respectively. The percentage of changes in serum homocysteine levels varied significantly among the different H. pylori infection statuses only in mild level (P = 0.024). Mean changed homocysteine values were higher in the subgroup of persistent infection than in the persistent negative subgroup (P = 0.004) and the eradication infection subgroup (P = 0.034). Serum homocysteine values were elevated only in the subgroup with over 3 years interval time and persistent infection (n = 107, mean paired differences = 1.1 ± 4.6 μmol/L, P = 0.014).

CONCLUSIONS

There is a relationship between H. pylori and serum homocysteine, and persistent infection leads to elevation of the latter.

Dyslipidemia and Associated Factors Among Patients Suspected to Have Helicobacter pylori Infection at Jimma University Medical Center, Jimma, Ethiopia

BACKGROUND

Dyslipidemia is a group of plasma lipid and lipoprotein abnormality that is metabolically associated, and it is categorized by low HDL-C and increased LDL-C, TGs, and total cholesterol (TC) levels. Colonization of the stomach by Helicobacter pylori (H. pylori) causes chronic inflammation of the stomach wall which can change some biochemical factors in the patient. On the association of H. pylori infection and its contributions to change in serum lipid profile, different studies reported varying outcomes.

OBJECTIVE

To assess the prevalence of dyslipidemia and associated factors among patients suspected for H. pylori infection in the outpatient department of Jimma University Medical Center, Jimma, Ethiopia.

MATERIALS AND METHODS

A hospital-based cross-sectional study was conducted from January 03 to April 05, 2019, at Jimma University Medical Center on 369 H. pylori suspected patients. The study subjects were selected by convenient sampling technique. About 5mL of blood was collected from an overnight fasting individual. Data were edited, coded, and entered into Epidata version 3.1 and exported to (SPSS) version 25 for analysis. Bivariate analysis was used to screen those variables which were candidates for multivariate analysis.

RESULTS

From the total study subjects 77.5% had at least one abnormality in lipid profile and 87.2% of H. pylori positive patients had at least one abnormality in lipid profile. Our study demonstrated that there was significant increase of mean ± SD of TC, TG, and LDL-C in H. pylori positive patients than H. pylori negative patients (P-value < 0.05). After adjusting for traditional dyslipidemia risk factors, H. pylori infection was an independent predictor of dyslipidemia (AOR 2.628, 95% CI 1.477-4.678, P=0.001).

CONCLUSION

An increase in prevalence of dyslipidemia among H. pylori positive patients indicates H. pylori infected patients have a possibility of altered lipid profile, therefore assessment of lipid profile in H. pylori infected patients is recommended.

Chronic Gastritis Is Associated with a Decreased High-Density Lipid Level: Histological Features of Gastritis Based on the Updated Sydney System

Chronic gastritis could activate a systemic inflammatory response that could result in adverse lipid profiles. To determine the severity of chronic gastritis, Helicobacter pylori (HP), mononuclear cell (lymphocytes and plasma cells), and neutrophil scores were assessed on the basis of the updated Sydney system (USS), which is widely used for histological grading. The aim of this study was to assess the relationships between gastric histological features and lipid profile levels. This study included 15,322 males and 5929 females who underwent a health checkup and gastric biopsy at the Kangbuk Samsung Medical Center (KBSMC). We analyzed whether the HP, mononuclear cell, and neutrophil grades according to the USS were related to serum leukocyte count, unhealthy behaviors, and lipid profile levels. Gastritis with HP, neutrophils, or moderate to severe mononuclear cells was associated with an elevated serum leukocyte count. A high leukocyte count was related to increased low-density lipoproteins (LDL) and triglycerides/very-low-density lipoprotein (VLDL) and decreased high-density lipoproteins (HDL). In multivariate analyses, chronic gastritis with HP or moderate to severe mononuclear cells was significantly associated with decreased HDL in males, while mononuclear cells were significantly related to decreased HDL in females. Chronic gastritis was associated with an increased systemic inflammatory response, which was associated with unfavorable lipid profiles, especially low HDL levels.

The Role of Toll-like Receptors in Atherothrombotic Cardiovascular Disease

Toll-like receptors (TLRs) are dominant components of the innate immune system. Activated by both pathogen-associated molecular patterns and damage-associated molecular patterns, TLRs underpin the pathology of numerous inflammation related diseases that include not only immune diseases, but also cardiovascular disease (CVD), diabetes, obesity, and cancers. Growing evidence has demonstrated that TLRs are involved in multiple cardiovascular pathophysiologies, such as atherosclerosis and hypertension. Specifically, a trial called the Canakinumab Anti-inflammatory Thrombosis Outcomes Study showed the use of an antibody that neutralizes interleukin-1β, reduces the recurrence of cardiovascular events, demonstrating inflammation as a therapeutic target and also the research value of targeting the TLR system in CVD. In this review, we provide an update of the interplay between TLR signaling, inflammatory mediators, and atherothrombosis, with an aim to identify new therapeutic targets for atherothrombotic CVD.

Hellenic consensus on Helicobacter pylori infection

The Hellenic Society of Gastroenterology recently organized the “Hellenic consensus on Helicobacter pylori (H. pylori) infection”. The aim of this publication is to report the guidelines in order to aid the national gastroenterology community in the management of H. pylori infection. Forty-one delegates from all Greek regions, including gastroenterologists, pathologists, clinical microbiologists, epidemiologists and basic scientists, were invited to this meeting. The participants were allocated to 1 of the 4 main topics of the meeting: i.e., H. pylori diagnosis and association with diseases; H. pylori and gastric cancer; H. pylori and extragastric associated disorders; and H. pylori treatment. The results of each subgroup were submitted to a final consensus vote that included all participants. Relevant data based on international and Greek publications were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded. The cutoff level of 70% was considered as acceptance for the final statement. It is hoped that the recommendations and conclusions of this report will guide Greek doctors in their daily practice concerning the management of H. pylori infection.

Helicobacter pylori infection is not related to increased carotid intima-media thickness in general population

The aim is to determine whether there is an independent association between Hp infection and carotid intima-media thickness (CIMT) in a cross-section observational study. Among of 14588 routine health check-up participants, 13770 subjects underwent the ¹³C-urea breath test (¹³C-UBT) and ultrasound measurement of CIMT. Traditional atherosclerotic risk factors were also recorded. The ratio of increased CIMT in Hp positive group (28.6%) was not significant difference compared with Hp negative group (29.7%) (p = 0.164). The HP infection rates was no significant difference between increased CIMT (38.4%) and non- increased CIMT (39.7%) patients. However, all the traditional atherosclerotic risk factors including age, gender, BMI, waistline, total cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, high density lipoprotein cholesterol, triglycerides, free fatty acid, homocysteine, systolic and diastolic blood pressure, fasting plasma glucose and C reactive protein were different between increased CIMT and non- increased CIMT participants. The odds of Hp infection for CIMT risk (OR 0.948; 95% CI 0.879-1.022; P = 0.164) was not higher in binary logistic regression analysis even after adjustment for traditional risk factors (OR 1.118; 95% CI 0.958-1.306; P = 0.157). Our study found no evidence of association between CIMT and HP infection.

Helicobacter pylori and extragastric diseases: A review

Helicobacter pylori (H. pylori) infection is very common and affects approximately half of the world population. It causes gastric diseases, but some authors have reported an association of H. pylori infection with other systemic manifestations beginning in 1994. The list of potential effects of H. pylori outside the stomach includes a number of extragastric manifestations and we focused on neurological, dermatological, hematologic, ocular, cardiovascular, metabolic, allergic, and hepatobiliary diseases. This review discusses these important reported manifestations that are not related to the gastrointestinal tract.

Current Helicobacter pylori infection is significantly associated with subclinical coronary atherosclerosis in healthy subjects: A cross-sectional study

Helicobacter pylori is a gastrointestinal pathogen known to be associated with cardiovascular disease (CVD). However, most analyses about the effect of H. pylori infection have been done in patients with a history of CVD but not in healthy subjects. We evaluated the association between H. pylori infection and subclinical atherosclerosis by using cardiac multidetector computed tomography (MDCT) in healthy subjects without previous CVD. From December 2007 to February 2014, 463 subjects who underwent the rapid urease test (CLO test), pulse-wave velocity (PWV) measurement, and MDCT for a self-referred health check-up were enrolled to this study. Helicobacter pylori infection was defined on the basis of CLO test positivity on endoscopic gastric biopsy. Significant coronary artery stenosis was defined as ≥50% stenosis in any of the major epicardial coronary vessel on MDCT. The CLO-positive subjects had a lower high-density lipoprotein-cholesterol (HDL-cholesterol) level compared to the CLO-negative subjects. The incidence of significant coronary stenosis was higher in the CLO-positive group (7.6% vs. 2.9%, P = 0.01). Furthermore, the number of subjects with coronary artery calcium score >0 and log{(number of segments with plaque)+1} were also significantly higher in the CLO-positive group. However, there was no statistical difference in the number of subjects with coronary artery calcium score >100, the prevalence of any plaque nor the plaque characteristics (calcified, mixed, or soft). Pulse-wave velocity (PWV) was neither associated with CLO test positivity. The CLO-positive group was 3-fold more likely to have significant coronary artery stenosis even after adjusting for confounding factors (adjusted odds ratio 2.813, 95% confidence interval 1.051–7.528, P = 0.04). In a healthy population, current H. pylori infection was associated with subclinical but significant coronary artery stenosis. The causal relationship between H. pylori infection and subclinical atherosclerosis in a “healthy” population remains to be investigated in the future.

The Impact of Helicobacter pylori Urease upon Platelets and Consequent Contributions to Inflammation

Gastric infection by Helicobacter pylori is considered a risk factor for gastric and duodenal cancer, and extragastric diseases. Previous data have shown that, in a non-enzymatic way, H. pylori urease (HPU) activates neutrophils to produce ROS and also induces platelet aggregation, requiring ADP secretion modulated by the 12-lipoxygenase pathway, a signaling cascade also triggered by the physiological agonist collagen. Here we investigated further the effects on platelets of recombinant versions of the holoenzyme HPU, and of its two subunits (HpUreA and HpUreB). Although HpUreA had no aggregating activity on platelets, it partially inhibited collagen-induced aggregation. HpUreB induced platelet aggregation in the nanomolar range, and also interfered dose-dependently on both collagen- and ADP-induced platelet aggregation. HPU-induced platelet aggregation was inhibited by antibodies against glycoprotein VI (GPVI), the main collagen receptor in platelets. Flow cytometry analysis revealed exposure of P-selectin in HPU-activated platelets. Anti-glycoprotein IIbIIIa (GPIIbIIIa) antibodies increased the binding of FITC-labeled HPU to activated platelets, whereas anti-GPVI did not. Evaluation of post-transcriptional events in HPU-activated platelets revealed modifications in the pre-mRNA processing of pro-inflammatory proteins, with increased levels of mRNAs encoding IL-1β and CD14. We concluded that HPU activates platelets probably through its HpUreB subunit. Activation of platelets by HPU turns these cells into a pro-inflammatory phenotype. Altogether, our data suggest that H. pylori urease, besides allowing bacterial survival within the gastric mucosa, may have an important, and so far overlooked, role in gastric inflammation mediated by urease-activated neutrophils and platelets.

Helicobacter pylori and cardiovascular complications: a mechanism based review on role of Helicobacter pylori in cardiovascular diseases

Heart disease comprises a wide class of cardiovascular abnormalities, including ischemic heart disease, myocardial infarction, atherosclerosis, and coronary artery disease. It is the leading cause of death all over the world. Several traditional and novel risk factors, such as infectious and noninfectious agents, have been associated with heart disease. Out of these, Helicobacter pylori has been recently introduced as an important etiological factor for heart disease. Numerous seroepidemiological findings observed H. pylori antibodies in the blood of a patient with cardiovascular complications. The bacteria survive in the epithelial cells of gastric organs and cause digestive complications. Excess inflammatory pathogenesis and prognosis stimulate an immune response that further causes significant disturbances in various factors like cytokines, fibrinogen, triglycerides, high density lipoprotein, C-reactive protein, heat shock protein, and white blood cell count, and provoke a number of problems such as atherosclerosis and prothrombic state, and cross-reactivity which eventually leads to heart diseases. H. pylori releases toxigenic nutrients, chiefly vacuolating cytotoxin gen A (Vac A) and cytotoxin associated gene A (Cag A), of which Cag A is more virulent and involved in the formation of cholesterol patches in arteries, induction of autoimmune disorder, and release of immune mediated response. Although numerous mechanisms have been correlated with H. pylori and heart disease, the exact role of bacteria is still ambiguous.

Clinical efficiency of Helicobacter pylori eradication in the treatment of patients with acute central serous chorioretinopathy

BACKGROUND

Although the majority of cases of acute central serous chorioretinopathy are self-limited, resolving spontaneously after a number of weeks, the recurrence rate is estimated to be 20-50 %, and some cases will be chronic, lasting 6 months or longer. The evidence of Helicobacter pylori infection appears more often in patients with central serous chorioretinopathy. The purpose of this work was to estimate the efficiency of H. pylori infection eradication in treatment of patients with acute central serous chorioretinopathy.

METHODS

Ninety-three patients with acute central serous chorioretinopathy participated in this study. Patients were divided into an experimental group (33 Helicobacter pylori-positive patients who received eradication treatment) and two control groups who did not receive eradication treatment: 29 H. pylori-positive patients and 31 H. pylori-negative patients. Research methods were best-corrected Snellen visual acuity, optical coherence tomography, fluorescein angiography. Research methods were best-corrected Snellen visual acuity, optical coherence tomography, static perimetry, and Amsler grid. The follow-up period was 2 years.

RESULTS

Helicobacter pylori eradication caused a decrease of disease duration at 3 months (p = 0.04) and recurrence frequency of 45.6 % (p = 0.03) as well as improvement of distant prognosis. After 2 years, visual acuity increased from 0.91 ± 0.07 to 0.99 ± 0.02 (p = 0.01), scotoma frequency decreased from 100 % eyes to 27.2 % (p = 0.001), and metamorphopsia frequency decreased from 57.6 % eyes to 39.4 % (p = 0.04).

CONCLUSIONS

Helicobacter pylori eradication is effective in the treatment of H. pylori-positive patients with acute central serous chorioretinopathy.

A Meta-Analysis of the Association between Helicobacter pylori Infection and Risk of Coronary Heart Disease from Published Prospective Studies

BACKGROUND

The association between helicobacter pylori (Hp) infection and coronary heart disease (CHD) has long been debated, and the results from previous meta-analysis are varied.

AIMS

The aim for this study was to identify the association between Hp and CHD using published perspective cohort studies.

MATERIALS AND METHODS

A systematic review and meta-analysis were performed on studies published from January, 1992 to April, 2014. All studies included used data from prospective cohort studies of CHD events or CHD deaths. Random effect models were applied in all estimations.

RESULTS

H. pylori infection increased the risk of CHD events by 11% (19 studies, n = 22,207, risk ratio (RR) = 1.11, 95% confidence interval (CI): 1.01-1.22). This effect was greater for studies that had less than 5 years' follow-up time (RR = 1.15, 95% CI: 1.00-1.32). However, this effect was not significant for studies that had follow-up times ≥10 years (n = 5100, RR = 1.04, 95% CI: 0.87-1.24). Neither Cag-A seropositive nor Cag-A seronegative strains of H. pylori were associated with a significantly increased risk of CHD events or deaths based on the current published data.

CONCLUSION

In conclusion, H. pylori infection increased the risk of CHD events, especially in a patient's early life, but this association was weaker or might be masked by other CHD risk factors in long-term observations.

Exosomes as nanocarriers for systemic delivery of the Helicobacter pylori virulence factor CagA

CagA, encoded by cytotoxin-associated gene A (cagA), is a major virulence factor of Helicobacter pylori, a gastric pathogen involved in the development of upper gastrointestinal diseases. Infection with cagA-positive H. pylori may also be associated with diseases outside the stomach, although the mechanisms through which H. pylori infection promotes extragastric diseases remain unknown. Here, we report that CagA is present in serum-derived extracellular vesicles, known as exosomes, in patients infected with cagA-positive H. pylori (n = 4). We also found that gastric epithelial cells inducibly expressing CagA secrete exosomes containing CagA. Addition of purified CagA-containing exosomes to gastric epithelial cells induced an elongated cell shape, indicating that the exosomes deliver functional CagA into cells. These findings indicated that exosomes secreted from CagA-expressing gastric epithelial cells may enter into circulation, delivering CagA to distant organs and tissues. Thus, CagA-containing exosomes may be involved in the development of extragastric disorders associated with cagA-positive H. pylori infection.

Exosomes as nanocarriers for systemic delivery of the Helicobacter pylori virulence factor CagA

CagA, encoded by cytotoxin-associated gene A (cagA), is a major virulence factor of Helicobacter pylori, a gastric pathogen involved in the development of upper gastrointestinal diseases. Infection with cagA-positive H. pylori may also be associated with diseases outside the stomach, although the mechanisms through which H. pylori infection promotes extragastric diseases remain unknown. Here, we report that CagA is present in serum-derived extracellular vesicles, known as exosomes, in patients infected with cagA-positive H. pylori (n = 4). We also found that gastric epithelial cells inducibly expressing CagA secrete exosomes containing CagA. Addition of purified CagA-containing exosomes to gastric epithelial cells induced an elongated cell shape, indicating that the exosomes deliver functional CagA into cells. These findings indicated that exosomes secreted from CagA-expressing gastric epithelial cells may enter into circulation, delivering CagA to distant organs and tissues. Thus, CagA-containing exosomes may be involved in the development of extragastric disorders associated with cagA-positive H. pylori infection.

Ureases as multifunctional toxic proteins: A review

Ureases are metalloenzymes that hydrolyze urea into ammonia and carbon dioxide. They were the first enzymes to be crystallized and, with them, the notion that enzymes are proteins became accepted. Novel toxic properties of ureases that are independent of their enzyme activity have been discovered in the last three decades. Since our first description of the neurotoxic properties of canatoxin, an isoform of the jack bean urease, which appeared in Toxicon in 1981, about one hundred articles have been published on "new" properties of plant and microbial ureases. Here we review the present knowledge on the non-enzymatic properties of ureases. Plant ureases and microbial ureases are fungitoxic to filamentous fungi and yeasts by a mechanism involving fungal membrane permeabilization. Plant and at least some bacterial ureases have potent insecticidal effects. This entomotoxicity relies partly on an internal peptide released upon proteolysis of ingested urease by insect digestive enzymes. The intact protein and its derived peptide(s) are neurotoxic to insects and affect a number of other physiological functions, such as diuresis, muscle contraction and immunity. In mammal models some ureases are acutely neurotoxic upon injection, at least partially by enzyme-independent effects. For a long time bacterial ureases have been recognized as important virulence factors of diseases by urease-producing microorganisms. Ureases activate exocytosis in different mammalian cells recruiting eicosanoids and Ca(2+)-dependent pathways, even when their ureolytic activity is blocked by an irreversible inhibitor. Ureases are chemotactic factors recognized by neutrophils (and some bacteria), activating them and also platelets into a pro-inflammatory "status". Secretion-induction by ureases may play a role in fungal and bacterial diseases in humans and other animals. The now recognized "moonlighting" properties of these proteins have renewed interest in ureases for their biotechnological potential to improve plant defense against pests and as potential targets to ameliorate diseases due to pathogenic urease-producing microorganisms.

Is the neutrophil-to-lymphocyte ratio a potential diagnostic marker for peptic ulcer perforation? A retrospective cohort study

OBJECTIVES

Peptic ulcer perforation (PUP) accounts for 5% of all abdominal emergencies and is recognized as a gastrointestinal emergency requiring rapid and efficient clinical evaluation and treatment. The mortality rate ranges from 10% to 40% among patients with perforation. In the present retrospective study, we examined the potential utility of the neutrophil-to-lymphocyte ratio (NLR) in early diagnosis of PUP; we asked whether this ratio allowed PUP and peptic ulcer disease to be distinguished.

METHODS

We enrolled the following patients: 58 with PUP, 62 with noncomplicated peptic ulcer diseases (NCPU), and 62 controls, between May 2010 and 2015. Patients who underwent surgical repair to treat PUP were included in the study group. Another group consisted of NCPU patients who had a noncomplicated peptic ulcer. The control group consisted of patients presenting with nonspecific abdominal pain to the emergency department.

RESULTS

The mortality rate was 5.2% in the PUP group. The white blood cell count, C-reactive protein, and NLRs were higher in the PUP compared to the other groups (P<.001 for all). The white blood cell count and NLR did not differ between the NCPU and control groups. The sensitivities, specificities, positive predictive values, and negative predictive values of the NLRs were 68.0%, 88.0%, 82.9%, and 72.9%, respectively.

CONCLUSIONS

We suggest that preoperative NLR aids in the diagnosis of PUP and can be used to distinguish this condition from peptic ulcer disease. Thus, the NLR should be calculated in addition to the clinical examination.

Association between Helicobacter pylori infection and stroke: a meta-analysis of prospective observational studies

BACKGROUND

Some studies have suggested an association between Helicobacter pylori infection and the risk of stroke, but the relationship remains controversial. The aim of this study was to obtain a more comprehensive estimate of H. pylori on the risk of stroke by performing a meta-analysis.

METHODS

A computerized search of PubMed, EMBASE, and the Cochrane library (including CENTRAL) up to February 2014 was performed to identify eligible studies. Prospective studies reported that a multivariate-adjusted estimate for the association between H. pylori and stroke were included. A random-effects model was used to calculate the overall combined risk.

RESULTS

Ten prospective observational studies (6 cohort studies, 4 nested case-control, or case-cohort studies within cohort studies) were included in the meta-analysis. The overall combined odds ratio for H. infection and stroke was .96 (95% confidence interval, .78-1.14). Similar results were yielded in patients with cytotoxin-associated gene-A seropositive strains. The combined estimates were robust across sensitivity analyses and had no observed publication bias.

CONCLUSIONS

In conclusion, our formal meta-analysis indicated no strong association between H. pylori infection and stroke, neither in those with cytotoxin-associated gene-A-positive infection. We believe that future epidemiologic studies of H. pylori and stroke are unlikely to be fruitful.

Effects of Helicobacter pylori infection and its eradication on lipid profiles and cardiovascular diseases

BACKGROUND

We aimed to examine the relationship of current Helicobacter pylori infection with lipid profile and cardiovascular disease and its eradication effect.

METHODS

Healthy subjects, who underwent routine checkup between October 2003 and December 2007, were followed up until June 2009. Helicobacter pylori and lipid profiles were measured both baseline and follow-up. Multiple logistic regression models for odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the effects of H. pylori infection and its eradication, on lipids and cardiovascular disease.

RESULTS

Current infection with H. pylori with 50.5% (6759/13383) at baseline increased low-density lipoprotein (LDL) and decreased high-density lipoprotein (HDL) than H. pylori-negative group. Successful eradication of H. pylori decreased the risk of high LDL compared with the persistent infection (OR 0.76, 95% CI 0.59-96), which was comparable to that of the persistent negative group (OR 0.82, 95% CI 0.70-0.97), and decreased the risk of low HDL (OR 0.68, 95% CI 0.49-0.96). Current infection of H. pylori increased the risk of cardiovascular disease (OR 3.27, 95% CI 1.31-8.14) at baseline, but its eradication failed to decrease the risk at a 2-year follow-up. However, persistent negative infection decreased the risk (OR 0.57, 95% CI 0.35-0.94) comparing to persistent positive infection at follow-up.

CONCLUSIONS

Current infection with H. pylori had a positive association with high LDL, low HDL, and cardiovascular disease. Successful H. pylori eradication decreased the risk of high LDL and low HDL, but did not reduce the risk of cardiovascular disease.

Beyond the stomach: An updated view of Helicobacter pylori pathogenesis, diagnosis, and treatment

Helicobacter pylori (H. pylori) is an extremely common, yet underappreciated, pathogen that is able to alter host physiology and subvert the host immune response, allowing it to persist for the life of the host. H. pylori is the primary cause of peptic ulcers and gastric cancer. In the United States, the annual cost associated with peptic ulcer disease is estimated to be $6 billion and gastric cancer kills over 700000 people per year globally. The prevalence of H. pylori infection remains high (> 50%) in much of the world, although the infection rates are dropping in some developed nations. The drop in H. pylori prevalence could be a double-edged sword, reducing the incidence of gastric diseases while increasing the risk of allergies and esophageal diseases. The list of diseases potentially caused by H. pylori continues to grow; however, mechanistic explanations of how H. pylori could contribute to extragastric diseases lag far behind clinical studies. A number of host factors and H. pylori virulence factors act in concert to determine which individuals are at the highest risk of disease. These include bacterial cytotoxins and polymorphisms in host genes responsible for directing the immune response. This review discusses the latest advances in H. pylori pathogenesis, diagnosis, and treatment. Up-to-date information on correlations between H. pylori and extragastric diseases is also provided.

Can Helicobacter pylori infection influence human reproduction?

Helicobacter pylori (H. pylori) infection could be associated with extra-digestive diseases. Here, we report the evidences concerning the decrease in reproductive potential occurring in individuals infected by H. pylori, especially by strains expressing CagA. This infection is more prevalent in individuals with fertility disorders. Infected women have anti-H. pylori antibodies in cervical mucus and follicular fluid that may decrease sperm motility and cross react immunologically with spermatozoa, conceivably hampering the oocyte/sperm fusion. Infection by CagA positive organisms enhances the risk of preeclampsia, which is a main cause of foetus death. These findings are supported by the results of experimental infections of pregnant mice, which may cause reabsorption of a high number of foetuses and alter the balance between Th1 and Th2 cell response. Infected men have decreased sperm motility, viability and numbers of normally shaped sperm and augmented systemic levels of inflammatory cytokines, such as tumor necrosis factor-α, which may damage spermatozoa. In countries where parasitic infestation is endemic, detrimental effects of infection upon spermatozoa may not occur, because the immune response to parasites could determine a switch from a predominant Th1 type to Th2 type lymphocytes, with production of anti-inflammatory cytokines. In conclusion, the evidences gathered until now should be taken into consideration for future studies aiming to explore the possible role of H. pylori infection on human reproduction.

Clinical significance of Helicobacter pylori infection in patients with acute coronary syndromes: an overview of current evidence

Although Helicobacter pylori (Hp) primarily colonizes gastric mucosa, it can occasionally inhabit in atherosclerotic plaques. Both forms of Hp infection may be involved in the pathogenesis of atherosclerosis via activation of a systemic or local inflammatory host reaction and induction of plaque progression and/or instability, possibly leading to coronary syndromes. The association between Hp infection and cardiovascular endpoint prevalence remains uncertain; however, it has been reported in many epidemiological investigations and may be reasonably explained by pathophysiological mechanisms. Besides the inflammatory pathway, Hp infection may trigger acute coronary syndromes by enhanced platelet reactivity and increased risk of gastrointestinal bleeding (type 2 myocardial infarction). The former seems to be predominantly related to the stimulatory effect of Hp infection on von Willebrand factor-binding and P-selectin activation, and the latter results from cytotoxic bacteria properties and aggravation of digestive tract injury related to aspirin or dual antiplatelet therapy. Despite these premises, the role of Hp infection in cardiovascular syndromes should still be recognized as controversial and requiring randomized, controlled trials to evaluate the outcome of Hp eradication in both cardiac and gastroenterological endpoints. Such need is also justified by potential bias of previous studies resulting from (1) using different diagnostic methods for identification of Hp infection, since only a small number of studies required confirmation of active Hp infection; and from (2) common lack of adjustment for important confounders such as socioeconomic status, smoking and effectiveness of eradication therapy, as well as the genetic characteristics of both the host and the bacterium.

The role of capillary transit time heterogeneity in myocardial oxygenation and ischemic heart disease

Ischemic heart disease (IHD) is characterized by an imbalance between oxygen supply and demand, most frequently caused by coronary artery disease (CAD) that reduces myocardial perfusion. In some patients, IHD is ascribed to microvascular dysfunction (MVD): microcirculatory disturbances that reduce myocardial perfusion at the level of myocardial pre-arterioles and arterioles. In a minority of cases, chest pain and reductions in myocardial flow reserve may even occur in patients without any other demonstrable systemic or cardiac disease. In this topical review, we address whether these findings might be caused by impaired myocardial oxygen extraction, caused by capillary flow disturbances further downstream. Myocardial blood flow (MBF) increases approximately linearly with oxygen utilization, but efficient oxygen extraction at high MBF values is known to depend on the parallel reduction of capillary transit time heterogeneity (CTH). Consequently, changes in capillary wall morphology or blood viscosity may impair myocardial oxygen extraction by preventing capillary flow homogenization. Indeed, a recent re-analysis of oxygen transport in tissue shows that elevated CTH can reduce tissue oxygenation by causing a functional shunt of oxygenated blood through the tissue. We review the combined effects of MBF, CTH, and tissue oxygen tension on myocardial oxygen supply. We show that as CTH increases, normal vasodilator responses must be attenuated in order to reduce the degree of functional shunting and improve blood-tissue oxygen concentration gradients to allow sufficient myocardial oxygenation. Theoretically, CTH can reach levels such that increased metabolic demands cannot be met, resulting in tissue hypoxia and angina in the absence of flow-limiting CAD or MVD. We discuss these predictions in the context of MVD, myocardial infarction, and reperfusion injury.

Significant association between serum interleukin-6 and Helicobacter pylori antibody levels among H. pylori-positive Japanese adults

Background. Interleukin-6 (IL-6) is a multifunctional cytokine produced by many types of cells. Inflammation plays a key role in the pathogenesis of atherosclerosis that is an underlying cause of coronary heart disease (CHD). Since the 1990s, some studies have shown an association between H. pylori infection and CHD, which may be mediated by inflammation. Therefore, this study aimed to evaluate the association between serum anti-H. pylori IgG levels and serum IL-6 levels in H. pylori-infected adults. Methods. We enrolled 158 subjects who visited a clinic located in an urban area to be tested for H. pylori infection, using the ¹³C-urea breath test, and who were found to be infected and subsequently received eradication. Results. The geometric mean serum IL-6 level was 1.78 pg/mL for men, 1.57 pg/mL for women, and 1.64 pg/mL overall. Logarithms of serum IL-6 levels were positively correlated with logarithms of serum H. pylori IgG levels (r = 0.24, P = 0.002). In multiple linear regression analysis adjusting for sex and age, the serum IL-6 level was still significantly associated with the IgG level in all subjects (β = 0.18, P = 0.012). Conclusion. Higher H. pylori IgG levels were significantly associated with higher serum IL-6 levels among H. pylori-infected individuals.

Association of H. pylori infection with insulin resistance and metabolic syndrome among Lebanese adults

BACKGROUND

Several epidemiological studies proposed an association between Helicobacter pylori ( H. pylori) infection with insulin resistance (IR) and metabolic syndrome (MetS). However, up to date there is no conclusive evidence regarding this association.

OBJECTIVES

To investigate the prevalence and correlates of H. pylori infection among Lebanese adults and to evaluate its association with IR and MetS.

MATERIALS AND METHODS

Stored blood samples of adults participating in the national Nutrition and Non-Communicable Diseases Risk factors survey conducted in Lebanon were used for this study (n = 308). H. pylori-specific immunoglobulin G antibody titers were measured by ELISA. Data available included, in addition to anthropometric measurements, sociodemographic and lifestyle characteristics, blood pressure, and biochemical indices (serum insulin, HDL, LDL, TAG, glucose). A HOMA -IR level was used to assess insulin resistance. The International Diabetes Federation criteria were used to classify study participants with MetS.

RESULTS

The prevalence of H. pylori infection in the study sample was 52% (95% CI, 46.43-57.57). A higher crowding index was associated with a 50% increase in the odds of infection (OR, 1.41; CI, 1.08-2.27). Blood pressure, waist circumference, serum HDL, LDL, TAG, and glucose levels were comparable between H. pylori positive and negative subjects. The odds of IR and MetS were not significantly different between the two groups.

CONCLUSION

Prevalence of H. pylori infection in Lebanon is comparable to other developing countries. Furthermore, our findings suggested no association of H. pylori infection with IR or MetS. Eradication of H. pylori infection to prevent IR or MetS is not warranted.

Helicobacter pylori infection, chronic atrophic gastritis and major cardiovascular events: a population-based cohort study

OBJECTIVE

There is debate whether infection with Helicobacter (H.) pylori, the main inducer of chronic atrophic gastritis (CAG), is a risk factor for cardiovascular disease and premature mortality.

METHODS

Serological measurements of H. pylori infection and pepsinogen (PG) I and II were obtained in a population-based German cohort of 9953 older adults (50-74 years). Cox regression was employed to estimate hazard ratios (HR) and 95% confidence intervals (CI) for myocardial infarction, stroke, cardiovascular and all-cause mortality during five-year follow-up.

RESULTS

According to serology, 4977 participants (51.9%) were infected with H. pylori (2604 with cytotoxin-associated gene A (cagA) strains) and 541 (5.7%) had CAG (PGI<70 ng/mL and PGI/PGII<3). During follow-up, 540 participants died (163 from cardiovascular causes), 170 experienced a primary myocardial infarction and 241 had a stroke. Neither cytotoxin-associated gene A (cagA) negative nor cagA positive H. pylori infections were associated with an increased risk for myocardial infarction, stroke or all-cause mortality. Intriguingly, infection with cagA positive H. pylori strains was inversely associated with cardiovascular mortality (HR, 0.62; CI: 0.41-0.94). No statistically significant associations were observed for the small group of participants with CAG, but point estimates of adjusted HRs for myocardial infarction, stroke and cardiovascular mortality were all below 1 (0.71, 0.59 and 0.65, respectively).

CONCLUSIONS

Our results do not support the hypothesis that H. pylori infection or CAG are risk factors for cardiovascular disease or mortality and instead suggest an inverse relationship of cagA positive H. pylori infection with fatal cardiovascular events.

Cure of alopecia areata after eradication of Helicobacter pylori: a new association?

Alopecia areata is a disease of the hair follicles, with strong evidence supporting autoimmune etiology. Alopecia areata is frequently associated with immune-mediated diseases with skin manifestations such as psoriasis and lichen planus, or without skin manifestations such as autoimmune thyroiditis and idiopathic thrombocytopenic purpura. Helicobacter pylori (H. pylori) infection is present in around 50% of the world's population and has been associated with a variety of immune-mediated extra-digestive disorders including autoimmune thyroiditis, idiopathic thrombocytopenic purpura, and psoriasis. A case of a 43-year old man with an 8-mo history of alopecia areata of the scalp and beard is presented. The patient was being treated by a dermatologist and had psychiatric support, without any improvement. He had a history of dyspepsia and the urea breath test confirmed H. pylori infection. The patient went into remission from alopecia areata after H. pylori eradication. If such an association is confirmed by epidemiological studies designed for this purpose, new therapeutic options could be available for these patients, especially in areas where infection with H. pylori is highly prevalent.

Influence of CagA-positive Helicobacter pylori strains on atherosclerotic carotid disease

Citotoxin-associated gene-A (CagA)-positive Helicobacter pylori strains have been associated with occurrence and destabilization of coronary atherosclerotic plaques. However, data on the relationship between CagA-positive H. pylori infection and carotid artery instability are lacking. Thus, the role of CagA antigen in patients with symptomatic and asymptomatic carotid atherosclerotic plaques was investigated. A total of 64 patients with advanced carotid artery stenosis, including 33 patients with symptomatic and 31 patients with asymptomatic internal carotid artery stenosis, verified by duplex ultrasound, all undergoing carotid endarterectomy, were studied. The control group consisted of 65 subjects without a history or presence of vascular diseases. Serology for H. pylori and CagA antigen was assessed in all participants. Specimens of atherosclerotic plaques obtained from all patients during carotid endarterectomy were analyzed immunohistochemically using anti-CagA monoclonal antibodies. The ultrasonographic plaque characteristics were also estimated. CagA antibody titers were significantly higher in symptomatic patients (8.8; range, 5.8-32.7) compared to asymptomatic patients (4.7; range, 2.1-8.8; P = 0.005) and the control group (5.0; range 2.2-7.9; P < 0.001). There was significant difference in echolucency (≥ 25% soft material) between the symptomatic and asymptomatic groups (P = 0.034) by ultrasonographic evaluation. Positive immunoreactivity between monoclonal CagA antibodies and antigens within atherosclerotic specimens was significantly higher among symptomatic patients compared to asymptomatic patients (97.0 vs. 74.2%; P = 0.009). H. pylori may play a role in the pathogenesis of the atherosclerotic process due to autoimmune mechanisms and even contribute to destabilization of carotid atherosclerotic plaques.

Infection by CagA-positive Helicobacter pylori strains may contribute to alter the sperm quality of men with fertility disorders and increase the systemic levels of TNF-alpha

This study was aimed to address the possibility that Helicobacter pylori infection may play a detrimental role in semen quality of men with idiopathic infertility. Infection by H. pylori and by strains expressing CagA was determined in 80 male infertile patients by Western blotting and ELISA. Semen analysis was performed by light microscopy and transmission electron microscopy quantitatively elaborated (fertility index, immaturity, necrosis, and apoptosis percentages). Systemic levels of IL-6 and TNF-alpha were evaluated. Infertile patients infected with H. pylori showed a low sperm quality respective to uninfected patients. Particularly, in CagA-positive patients we observed a significant reduction in sperm motility and in the fertility index, while apoptosis and necrosis were increased. In these patients, the means of systemic TNF-alpha levels were higher than those of uninfected patients. The negative influence of CagA-positive H. pylori infection on sperm quality may help to understand the role of chronic infections in reproductive disorders.

Helicobacter pylori urease activates blood platelets through a lipoxygenase-mediated pathway

The bacterium Helicobacter pylori causes peptic ulcers and gastric cancer in human beings by mechanisms yet not fully understood. H. pylori produces urease which neutralizes the acidic medium permitting its survival in the stomach. We have previously shown that ureases from jackbean, soybean or Bacillus pasteurii induce blood platelet aggregation independently of their enzyme activity by a pathway requiring platelet secretion, activation of calcium channels and lipoxygenase-derived eicosanoids. We investigated whether H. pylori urease displays platelet-activating properties and defined biochemical pathways involved in this phenomenon. For that the effects of purified recombinant H. pylori urease (HPU) added to rabbit platelets were assessed turbidimetrically. ATP secretion and production of lipoxygenase metabolites by activated platelets were measured. Fluorescein-labelled HPU bound to platelets but not to erythrocytes. HPU induced aggregation of rabbit platelets (ED(50) 0.28 microM) accompanied by ATP secretion. No correlation was found between platelet activation and ureolytic activity of HPU. Platelet aggregation was blocked by esculetin (12-lipoxygenase inhibitor) and enhanced approximately 3-fold by indomethacin (cyclooxygenase inhibitor). A metabolite of 12-lipoxygenase was produced by platelets exposed to HPU. Platelet responses to HPU did not involve platelet-activating factor, but required activation of verapamil-inhibitable calcium channels. Our data show that purified H. pylori urease activates blood platelets at submicromolar concentrations. This property seems to be common to ureases regardless of their source (plant or bacteria) or quaternary structure (single, di- or tri-chain proteins). These properties of HPU could play an important role in pathogenesis of gastrointestinal and associated cardiovascular diseases caused by H. pylori.

Socioeconomic and race/ethnic patterns in persistent infection burden among U.S. adults

BACKGROUND

The pathophysiological mechanisms that underlie health disparities by socioeconomic status and race/ethnicity are poorly understood. Promising new research suggests that the burden of persistent infection may influence adult disease risk and mortality. This article examines how multiple persistent infections cluster within individuals and how this clustering varies by socioeconomic position and race/ethnicity in U.S. adults.

METHODS

We analyze data from the National Health and Nutrition Examination Survey III (N = 19,275) for adults aged 17-90 years. The clustering of infections within individuals is studied using tetrachoric correlations. Multiple indicator multiple cause models are used to analyze the infection burden construct as measured by seropositivity to Helicobacter pylori, cytomegalovirus, herpes simplex virus-1, and hepatitis B, focusing on the burden's distribution by socioeconomic position and race/ethnicity. The results are corroborated using ordered logistic regression for a commonly used count index of individual infections.

RESULTS

Seroprevalence of individual persistent infections is positively correlated, suggesting common factors related to exposure or susceptibility. Education, income, and race/ethnicity are strong and significant independent predictors of infection burden in U.S. adults in all models.

CONCLUSION

The disproportionate burden of persistent infections among disadvantaged groups across all ages may be one biologic pathway by which low socioeconomic position is related to increased rates of morbidity and mortality in the United States.

Early origins of health disparities: burden of infection, health, and socioeconomic status in U.S. children

Recent work in biodemography has suggested that lifetime exposure to infection and inflammation may be an important determinant of later-life morbidity and mortality. Early exposure to infections during critical periods can predispose individuals to chronic disease, in part through the reallocation of energy away from development needed for immune and inflammatory responses. Furthermore, markers of inflammation are known to vary by socioeconomic status in adults and may contribute to overall socioeconomic health inequalities, but little is known about how the sources of this inflammation differ over the life course. This paper uses novel biomarker data from the Third National Health and Nutrition Examination Survey (NHANES III) to test the association of the burden of common chronic infections (Helicobacter pylori (H. pylori), cytomegalovirus (CMV), herpes simplex virus-1 (HSV-1), hepatitis A and hepatitis B) with height-for-age and asthma/chronic respiratory conditions in U.S. children ages 6 and older, and the association of these chronic infections to children's socioeconomic status. A higher burden of infection is found to be associated with lower height-for-age as well as an increased likelihood of asthma net of race/ethnicity, family income, and parental education. Children with lower family income, lower parental education, and non-white race/ethnicity have a higher likelihood of infection with several individual pathogens as well as the overall burden of infection. Differential exposure and/or susceptibility to infections may be one mechanism through which early social factors get embodied and shape later-life health outcomes.

Helicobacter pylori-induced inhibition of vascular endothelial cell functions: a role for VacA-dependent nitric oxide reduction

Epidemiological and clinical studies provide compelling support for a causal relationship between Helicobacter pylori infection and endothelial dysfunction, leading to vascular diseases. However, clear biochemical evidence for this association is limited. In the present study, we have conducted a comprehensive investigation of endothelial injury in bovine aortic endothelial cells (BAECs) induced by H. pylori-conditioned medium (HPCM) prepared from H. pylori 60190 [vacuolating cytotoxin A (Vac(+))]. BAECs were treated with either unconditioned media, HPCM (0-25% vol/vol), or Escherichia coli-conditioned media for 24 h, and cell functions were monitored. Vac(+) HPCM significantly decreased BAEC proliferation, tube formation, and migration (by up to 44%, 65%, and 28%, respectively). Posttreatment, we also observed sporadic zonnula occludens-1 immunolocalization along the cell-cell border, and increased BAEC permeability to FD40 Dextran, indicating barrier reduction. These effects were blocked by 5-nitro-2-(3-phenylpropylamino)benzoic acid (VacA inhibitor) and were not observed with conditioned media prepared from either VacA-deleted H. pylori or E. coli. The cellular mechanism mediating these events was also considered. Vac(+) HPCM (but not Vac(-)) reduced nitric oxide (NO) by >50%, whereas S-nitroso-N-acetylpenicillamine, an NO donor, recovered all Vac(+) HPCM-dependent effects on cell functions. We further demonstrated that laminar shear stress, an endothelial NO synthase/NO stimulus in vivo, could also recover the Vac(+) HPCM-induced decreases in BAEC functions. This study shows, for the first time, a significant proatherogenic effect of H. pylori-secreted factors on a range of vascular endothelial dysfunction markers. Specifically, the VacA-dependent reduction in endothelial NO is indicated in these events. The atheroprotective impact of laminar shear stress in this context is also evident.

Helicobacter pylori eradication therapy: indications, efficacy and safety

BACKGROUND

Helicobacter pylori infects up to half of the world's population. It remains the major cause of peptic ulcer disease and is recognised as a carcinogen for its role in gastric carcinogenesis. Successful eradication of the bacteria is associated with improved health outcomes including fewer dyspeptic symptoms, reduced peptic ulcer recurrence and rebleeding, reduced peptic ulcer risk with NSAIDs and as a cure for low-grade gastric MALT lymphoma. The risk of gastric cancer is reduced in those without premalignant mucosal abnormalities at the time of eradication.

OBJECTIVE

This review outlines the current indications and options for therapy of H. pylori with particular reference to drug-induced adverse events associated with treatment.

METHODS

The indications for H. pylori eradication are evidence-based and in accordance with recent consensus statements and recommendations. The eradication treatment is based on numerous clinical trials and meta-analyses.

RESULTS/CONCLUSION

Eradication therapy, in general, is safe and well tolerated. Antibiotic therapy may be associated with significant drug adverse reactions, especially gastrointestinal symptoms.