Detection of Chlamydia pneumoniae and Helicobacter pylori in atherosclerotic plaques of carotid artery by polymerase chain reaction

Traditional and nontraditional lipid parameters in Helicobacter pylori infection

Aims: This study sought to evaluate the relationship between Helicobacter pylori infection and traditional and nontraditional lipid parameters, including atherogenic index of plasma, cardiogenic risk ratio, atherogenic coefficient and remnant cholesterol. Methods: After the application of exclusion criteria, 309 patients were allocated according to the absence (n = 52) or presence (n = 257) of H. pylori infection. Results: Total cholesterol, low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) levels were nonsignificantly higher, and HDL-C levels were nonsignificantly lower, in the H. pylori-infected patient group. Triglyceride-to-HDL-C ratio, LDL-C-to-HDL-C ratio, atherogenic index of plasma, cardiogenic risk ratio, atherogenic coefficient and remnant cholesterol were comparable among groups. Conclusion: There was no significant association between H. pylori infection and traditional and nontraditional novel lipid parameters and indices.

Emerging Roles of Extracellular Vesicle-Delivered Circular RNAs in Atherosclerosis

Atherosclerosis (AS) is universally defined as chronic vascular inflammation induced by dyslipidaemia, obesity, hypertension, diabetes and other risk factors. Extracellular vesicles as information transmitters regulate intracellular interactions and their important cargo circular RNAs are involved in the pathological process of AS. In this review, we summarize the current data to elucidate the emerging roles of extracellular vesicle-derived circular RNAs (EV-circRNAs) in AS and the mechanism by which EV-circRNAs affect the development of AS. Additionally, we discuss their vital role in the progression from risk factors to AS and highlight their great potential for use as diagnostic biomarkers of and novel therapeutic strategies for AS.

Association of Helicobacter pylori infection with coronary artery disease: is it an independent risk factor?

BACKGROUND

Coronary artery disease (CAD) is a dilemma and a serious cause of morbidity and mortality worldwide. Since CAD has been seen in people without the conventional risk factors like smoking, diabetes, and hypertension, the infectious theory being a risk factor has arisen.

MAIN BODY

Helicobacter pylori (HP) infection is the most common infection affecting the vast majority of the population worldwide. HP grows in the gastrointestinal tract (GIT) and responsible for chronic gastritis, peptic ulcer, gastric adenocarcinoma, and gastric lymphoma. A review of medical literature mainly PubMed has revealed several studies reporting that HP pathogenesis extends beyond the GIT to be a predisposing factor for atherosclerosis, dyslipidemia, thrombosis, and CAD. However, it remains a controversial issue that warrants extensive research.

CONCLUSION

This article gives insight into the diversity of opinions, evidence, and theories regarding the association between HP infection and CAD. The idea that CAD may be managed with antibiotics in certain patients seems to be creative and inspiring. More research is mandatory to either verify or reject this proposed correlation with strong scientific evidence and also to demonstrate the implications of the results on CAD management and outcome.

Naked-Eye Enumeration of Single Chlamydia pneumoniae Based on Light Scattering of Gold Nanoparticle Probe

Chlamydia pneumoniae is a spherical zoonotic pathogen with a diameter of ∼200 nm, which can lead to a wide range of acute and chronic diseases in human body. Early and reliable on-site detection of C. pneumoniae is the key step to control the spread of the pathogen. However, the lack of a current technology with advantages of rapidity, ultrasensitivity, and convenience limits the implementation of traditional techniques for on-site detection of C. pneumoniae. Herein, we developed a naked-eye counting of C. pneumoniae based on the light scattering properties of gold nanoparticle (GNP) under dark-field microscopy (termed "GNP-labeled dark-field counting strategy"). The recognition of single C. pneumoniae by anti-C. pneumoniae antibodies-functionalized GNP probes with size of 15 nm leads to the formation of wreath-like structure due to the strong scattered light resulted from hundreds of GNP probes binding on one C. pneumoniae under dark-field microscopy. Hundreds of GNP probes can bind to the surface of C. pneumoniae due to the high stability and specificity of the nucleic acid immuno-GNP probes, which generates by the hybridization of DNA-modified GNP with DNA-functionalized antibodies. The limit of detection (LOD) of the GNP-labeled dark-field counting strategy for C. pneumoniae detection in spiked samples or real samples is down to four C. pneumoniae per microliter, which is about 4 times more sensitive than that of quantitative polymerase chain reaction (qPCR). Together with the advantages of the strong light scattering characteristic of aggregated GNPs under dark-field microscopy and the specific identification of functionalized GNP probes, we can detect C. pneumoniae in less than 30 min using a cheap and portable microscope even if the sample contains only a few targets of interest and other species at high concentration. The GNP-labeled dark-field counting strategy meets the demands of rapid detection, low cost, easy to operate, and on-site detection, which paves the way for early and on-site detection of infectious pathogens.

Helicobacter pylori Infection Impairs Endothelial Function Through an Exosome-Mediated Mechanism

Background

Epidemiological studies have suggested an association between Helicobacter pylori (H pylori) infection and atherosclerosis through undefined mechanisms. Endothelial dysfunction is critical to the development of atherosclerosis and related cardiovascular diseases. The present study was designed to test the hypothesis that H pylori infection impaires endothelial function through exosome‐mediated mechanisms.

Methods and Results

Young male and female patients (18‐35 years old) with and without H pylori infection were recruited to minimize the chance of potential risk factors for endothelial dysfunction for the study. Endothelium‐dependent flow‐mediated vasodilatation of the brachial artery was evaluated in the patients and control subjects. Mouse infection models with CagA⁺H pylori from a gastric ulcer patient were created to determine if H pylori infection‐induced endothelial dysfunction could be reproduced in animal models. H pylori infection significantly decreased endothelium‐dependent flow‐mediated vasodilatation in young patients and significantly attenuated acetylcholine‐induced endothelium‐dependent aortic relaxation without change in nitroglycerin‐induced endothelium‐independent vascular relaxation in mice. H pylori eradication significantly improved endothelium‐dependent vasodilation in both patients and mice with H pylori infection. Exosomes from conditioned media of human gastric epithelial cells cultured with CagA⁺H pylori or serum exosomes from patients and mice with H pylori infection significantly decreased endothelial functions with decreased migration, tube formation, and proliferation in vitro. Inhibition of exosome secretion with GW4869 effectively preserved endothelial function in mice with H pylori infection.

Conclusions

H pylori infection impaired endothelial function in patients and mice through exosome‐medicated mechanisms. The findings indicated that H pylori infection might be a novel risk factor for cardiovascular diseases.

The microbiome in autoimmune rheumatic disease

Microbial contributions to the immunopathogenesis of autoimmune rheumatic diseases have been studied since the advent of germ theory in the 19th century. With the exception of Group A Streptococcus in rheumatic fever, early studies failed to establish causal relationships between specific pathobionts and rheumatic disease. Today, systemic autoimmune diseases are thought to result from a complex interplay of environmental factors, individual genetic risk, and stochastic events. Interactions of microbiota and the immune system have been shown to promote and sustain chronic inflammation and autoimmunity. In mechanistic studies, microbe-immune cell interactions have been implicated in the initiation of autoimmune rheumatic diseases, e.g., through the posttranslational modification of autoantigens in rheumatoid arthritis or through neutrophil cell death and cross-reactivity with commensal orthologs in systemic lupus erythematosus. In parallel, modern molecular techniques have catalyzed the study of the microbiome in systemic autoimmune diseases. Here, I review current insights gained into the skin, oral, gut, lung, and vascular microbiome in connective tissue diseases and vasculitis. Mechanism relevant to the development and propagation of autoimmunity will be discussed whenever explored. While studies on autoimmune rheumatic disease have almost invariably shown abnormal microbiome structure (dysbiosis), substantial variability in microbial composition between studies makes generalization difficult. Moreover, an etiopathogenic role of specific pathobionts cannot be inferred by association alone. Integrating descriptive studies of microbial communities with hypothesis-driven research informed by immunopathogenesis will be important in elucidating targetable mechanisms in preclinical and established rheumatic disease.

Both diet and Helicobacter pylori infection contribute to atherosclerosis in pre- and postmenopausal cynomolgus monkeys

A number of viruses and bacterial species have been implicated as contributors to atherosclerosis, potentially providing novel pathways for prevention. Epidemiological studies examining the association between Helicobacter pylori and cardiovascular disease have yielded variable results and no studies have been conducted in nonhuman primates. In this investigation, we examined the relationship between H. pylori infection and atherosclerosis development in socially housed, pre- and postmenopausal cynomolgus macaques consuming human-like diets. Ninety-four premenopausal cynomolgus monkeys (Macaca fascicularis) were fed for 36 months an atherogenic diet deriving its protein from either casein lactalbumin(CL) or high isoflavone soy (SOY). Animals were then ovariectomized and fed either the same or the alternate diet for an additional 36 months. Iliac artery biopsies were obtained at the time of ovariectomy and iliac and coronary artery sections were examined at the end of the study. Evidence of H. pylori infection was found in 64% of the monkeys and 46% of animals had live H. pylori within coronary atheromas as determined by mRNA-specific in situ hybridization. There was a significant linear relationship between the densities of gastric and atheroma organisms. Helicobactor pylori infection correlated with increased intimal plaque area and thickness at both the premenopausal and postmenopausal time points and regardless of diet (p< 0.01), although animals consuming the SOY diet throughout had the least amount of atherosclerosis. Additionally, plasma lipid profiles, intimal collagen accumulation, ICAM-1, and plaque macrophage densities were adversely affected by H. pylori infection among animals consuming the CL diet, while the SOY diet had the opposite effect. Plaque measurements were more highly associated with the densities of cagA-positive H. pylori within coronary atheromas than with the densities of gastric organisms, whereas plasma lipid changes were associated with H. pylori infection, but not cagA status. This study provides strong evidence that live H. pylori infects atheromas, exacerbates atherosclerotic plaque development, and alters plasma lipid profiles independently of diet or hormonal status. Finally, socially subordinate animals relative to their dominant counterparts had a greater prevalence of H. pylori, suggesting a stress effect. The results indicate that early H. pylori eradication could prevent or delay development of cardiovascular disease.

One piece biopsy for both rapid urease test and cultivation of Helicobacter pylori

BACKGROUND & AIMS

Increasing antibiotic resistance among Helicobacter pylori isolates and the unsuccessful attempts at eradication can impose many costs to both healthcare systems and patients. The present study intended to find a way from which H. pylori could be isolated from biopsies with less invasive procedures undertaken on infected patients.

METHODS

A biopsy specimen from each patient with gastric disorders was put into urea-containing agar. After two hours, the specimens were removed from agar and placed into tubes containing 1 ml 20% glucose solution. Then, the specimens were inoculated onto the Columbia agar and incubated under microaerophilic conditions. The grown colonies were identified as H.pylori based on the microbiology tests and PCR.

RESULTS

Overall, 449 biopsy specimens were collected from the patients. Of all biopsies, 219 (48.8%) revealed positive results in the rapid urease test. Using the aforementioned method, 158 (35.2%) culture positive biopsy specimens were obtained.

CONCLUSION

The researchers attempted to use one biopsy specimen for both rapid urease and culture tests. This method causes fewer injuries of gastric tissue and allows antimicrobial susceptibility testing and characterization in detail of the isolated organism.

The Role of the Microbiota in the Diabetic Peripheral Artery Disease

Vascular complications of diabetes mellitus represent a major public health problem. Although many steps forward have been made to define the causes and to find the best possible therapies, the problem remains crucial. In recent years, more and more evidences have defined a link between microbiota and the initiation, promotion, and evolution of atherosclerotic disease, even in the diabetic scenario. There is an urgency to develop the knowledge of modern medicine about the link between gut microbiota and its host's metabolic pathways, and it would be useful to understand and justify the interindividual diversity of clinical disease presentation of diabetic vascular complication even if an optimization of pharmacological treatment has been made or in the case of young patients where hypertension, dyslipidemia, and diabetes are not able to justify a very quick progress of atherosclerotic process. The aim of the present review is to gather all the best available evidence in this regard and to define a new role of the microbiota in this field, from biomarker to possible therapeutic target.

Helicobacter pylori cholesterol glucosylation modulates autophagy for increasing intracellular survival in macrophages

Cholesterol-α-glucosyltransferase (CGT) encoded by the type 1 capsular polysaccharide biosynthesis protein J (capJ) gene of Helicobacter pylori converts cellular cholesterol into cholesteryl glucosides. H. pylori infection induces autophagy that may increase bacterial survival in epithelial cells. However, the role of H. pylori CGT that exploits lipid rafts in interfering with autophagy for bacterial survival in macrophages has not been investigated. Here, we show that wild-type H. pylori carrying CGT modulates cholesterol to trigger autophagy and restrain autophagosome fusion with lysosomes, permitting a significantly higher bacterial burden in macrophages than that in a capJ-knockout (∆CapJ) mutant. Knockdown of autophagy-related protein 12 impairs autophagosome maturation and decreases the survival of internalised H. pylori in macrophages. These results demonstrate that CGT plays a crucial role in the manipulation of the autophagy process to impair macrophage clearance of H. pylori.

Review: Impact of Helicobacter pylori on Alzheimer's disease: What do we know so far?

BACKGROUND

Helicobacter pylori has changed radically gastroenterologic world, offering a new concept in patients' management. Over time, more medical data gave rise to diverse distant, extragastric manifestations and interactions of the "new" discovered bacterium. Special interest appeared within the field of neurodegenerative diseases and particularly Alzheimer's disease, as the latter and Helicobacter pylori infection are associated with a large public health burden and Alzheimer's disease ranks as the leading cause of disability. However, the relationship between Helicobacter pylori infection and Alzheimer's disease remains uncertain.

METHODS

We performed a narrative review regarding a possible connection between Helicobacter pylori and Alzheimer's disease. All accessible relevant (pre)clinical studies written in English were included. Both affected pathologies were briefly analyzed, and relevant studies are discussed, trying to focus on the possible pathogenetic role of this bacterium in Alzheimer's disease.

RESULTS

Data stemming from both epidemiologic studies and animal experiments seem to be rather encouraging, tending to confirm the hypothesis that Helicobacter pylori infection might influence the course of Alzheimer's disease pleiotropically. Possible main mechanisms may include the bacterium's access to the brain via the oral-nasal-olfactory pathway or by circulating monocytes (infected with Helicobacter pylori due to defective autophagy) through disrupted blood-brain barrier, thereby possibly triggering neurodegeneration.

CONCLUSIONS

Current data suggest that Helicobacter pylori infection might influence the pathophysiology of Alzheimer's disease. However, further large-scale randomized controlled trials are mandatory to clarify a possible favorable effect of Helicobacter pylori eradication on Alzheimer's disease pathophysiology, before the recommendation of short-term and cost-effective therapeutic regimens against Helicobacter pylori-related Alzheimer's disease.

Hyperglycemia combined Helicobacter pylori infection increases risk of synchronous colorectal adenoma and carotid artery plaque

Background

Cardiovascular disease and colorectal cancer have severe consequences to human health and may occur simultaneously or sequentially. Carotid artery plaque is a predictor of cardiovascular disease, and colorectal adenoma is a premalignant lesion of colorectal cancer. We investigated the core risk factors of carotid artery plaque and colorectal adenoma.

Results

In total, 2361 subjects were enrolled. In multivariate analysis, age ≥ 60 years, male sex, BMI > 27, LDL > 130 mg/dL, HbA_1c ≥ 6.5%, hs-CRP > 0.3 mg/L and H. pylori infection were independent risk factors for synchronous colorectal adenoma and carotid artery plaque formation. In the H. pylori-positive and -negative groups, the proportions and odds ratio (OR) for synchronous colon adenoma and carotid artery plaque increased with increasing HbA1c. OR for synchronous colon adenoma and carotid artery plaque was significantly higher in the participants with HbA_1c levels of 5.7%–6.4% and HbA1c ≥ 6.5% than in those with normal HbA_1c in the H. pylori-negative group. The OR was more significant increased for H. pylori-positive patients when HbA_1c level ≥ 6.5% was 15.87 (95% CI 8.661–29.082, p < 0.0001).

Materials and Methods

The records of 4669 subjects aged > 40 years who underwent bidirectional gastrointestinal endoscopy and carotid artery ultrasound examination on the same day or within 12 months of endoscopy examination from January 2006 to December 2015 were reviewed. All subjects had a gastric biopsy specimen tested for Helicobacter pylori.

Conclusions

Hyperglycemia combined with H. pylori infection was an increased risk factor for synchronous colorectal adenoma and carotid artery plaque formation. Diabetes control and H. pylori eradication may be warranted in higher prevalence areas.

Helicobacter pylori infection and severity of coronary atherosclerosis in patients with chronic coronary artery disease

AIM

Controversy exists concerning the relation between Helicobacter pylori (HP) infection and coronary artery disease (CAD). We aimed to examine the relationship between HP infection and severity of coronary atherosclerosis in patients with chronic CAD.

PATIENTS AND METHODS

A total of 150 patients (109 [73%] men; mean age 62.61±10.23 years) scheduled for coronary artery bypass grafting surgery were consecutively enrolled in the cross-sectional study. According to rapid urease test and/or gastric biopsy samples stained with hematoxylin and eosin and according to Giemsa, patients were classified as HP positive (n=87; 58%) or HP negative (n=63; 42%). Coronary angiograms were scored by quantitative assessment, using multiple angiographic scoring system: 1) vessel score (number of coronary arteries stenosed ≥50%), 2) Gensini score (assigning a severity score to each coronary stenosis according to the degree of luminal narrowing and its topographic importance) and 3) angiographic severity score (number of coronary artery segments stenosed ≥50%).

RESULTS

In comparison to HP-negative patients, HP-positive patients were more frequently hypertensive (P=0.014), had higher values of systolic (P=0.043) and diastolic (P=0.005) blood pressure and total cholesterol (P=0.013) and had lower values of high-density lipoprotein-cholesterol (HDL-C; P=0.010). There were no significant differences between the groups in the severity of coronary atherosclerosis: vessel score (P=0.152), Gensini score (P=0.870) and angiographic severity score (P=0.734).

CONCLUSION

It is likely that HP infection is not a risk factor for the severity of coronary atherosclerosis in chronic CAD patients.

An Unsettled Debate About the Potential Role of Infection in Pathogenesis of Atherosclerosis

Association of infection with atherosclerosis is by no means new. Several sero-epidemiological and pathologic studies as well as animal models have shown a link between infection and atherosclerosis. Exciting discoveries in recent times related to role of inter-individual genetic variation in modulating inflammatory response to infection have reignited the enthusiasm in proving a causal link between infection and atherosclerosis. The purpose of this article was to review and analyze the available evidence linking infection with atherosclerosis.

Review. The Link between Periodontal Disease, Inflammation and Atherosclerosis — an Interdisciplinary Approach

Periodontal disease is a chronic inflammatory disease that results from the activity of altered oral microbiome, leading to altered immune reaction, destruction of tissues supporting the teeth, and oral bone loss. This disease is particularly associated with an expressed systemic inflammation, being considered nowadays an inflammatory disorder. At the same time, inflammation has been recognized to play a major role in the development of atherosclerotic lesions. Atheromatous plaque formation is triggered by alterations in the structure of the endothelium, which lead to the expression of adhesion molecules and recruitment of immune cells such as macrophages, in the arterial wall. While the association between periodontal disease, inflammation and cardiovascular diseases has been well established, the causality relation between these three entities has not been demonstrated so far. This review presents the most common advances in understanding the complex link between periodontal disease, inflammation and atherosclerosis, as a common pathway leading to increased cardiovascular risk.

Microbiota, Immune Subversion, and Chronic Inflammation

Several host-adapted pathogens and commensals have evolved mechanisms to evade the host innate immune system inducing a state of low-grade inflammation. Epidemiological studies have also documented the association of a subset of these microorganisms with chronic inflammatory disorders. In this review, we summarize recent studies demonstrating the role of the microbiota in chronic inflammatory diseases and discuss how specific microorganisms subvert or inhibit protective signaling normally induced by toll-like receptors (TLRs). We highlight our work on the oral pathogen Porphyromonas gingivalis and discuss the role of microbial modulation of lipid A structures in evasion of TLR4 signaling and resulting systemic immunopathology associated with atherosclerosis. P. gingivalis intrinsically expresses underacylated lipid A moieties and can modify the phosphorylation of lipid A, leading to altered TLR4 signaling. Using P. gingivalis mutant strains expressing distinct lipid A moieties, we demonstrated that expression of antagonist lipid A was associated with P. gingivalis-mediated systemic inflammation and immunopathology, whereas strains expressing agonist lipid A exhibited modest systemic inflammation. Likewise, mice deficient in TLR4 were more susceptible to vascular inflammation after oral infection with P. gingivalis wild-type strain compared to mice possessing functional TLR4. Collectively, our studies support a role for P. gingivalis-mediated dysregulation of innate and adaptive responses resulting in immunopathology and systemic inflammation. We propose that anti-TLR4 interventions must be designed with caution, given the balance between the protective and destructive roles of TLR signaling in response to microbiota and associated immunopathologies.

The Helicobacter cinaedi antigen CAIP participates in atherosclerotic inflammation by promoting the differentiation of macrophages in foam cells

Recent studies have shown that certain specific microbial infections participate in atherosclerosis by inducing inflammation and immune reactions, but how the pathogens implicated in this pathology trigger the host responses remains unknown. In this study we show that Helicobacter cinaedi (Hc) is a human pathogen linked to atherosclerosis development since at least 27% of sera from atherosclerotic patients specifically recognize a protein of the Hc proteome, that we named Cinaedi Atherosclerosis Inflammatory Protein (CAIP) (n = 71). CAIP appears to be implicated in this pathology because atheromatous plaques isolated from atherosclerotic patients are enriched in CAIP-specific T cells (10%) which, in turn, we show to drive a Th1 inflammation, an immunopathological response typically associated to atherosclerosis. Recombinant CAIP promotes the differentiation and maintenance of the pro-inflammatory profile of human macrophages and triggers the formation of foam cells, which are a hallmark of atherosclerosis. This study identifies CAIP as a relevant factor in atherosclerosis inflammation linked to Hc infection and suggests that preventing and eradicating Hc infection could reduce the incidence of atherosclerosis.

Immune dysregulation mediated by the oral microbiome: potential link to chronic inflammation and atherosclerosis

Cardiovascular disease is an inflammatory disorder characterized by the progressive formation of plaque in coronary arteries, termed atherosclerosis. It is a multifactorial disease that is one of the leading causes of death worldwide. Although a number of risk factors have been associated with disease progression, the underlying inflammatory mechanisms contributing to atherosclerosis remain to be fully delineated. Within the last decade, the potential role for infection in inflammatory plaque progression has received considerable interest. Microbial pathogens associated with periodontal disease have been of particular interest due to the high levels of bacteremia that are observed after routine dental procedures and every day oral activities, such as tooth brushing. Here, we explore the potential mechanisms that may explain how periodontal pathogens either directly or indirectly elicit immune dysregulation and consequently progressive inflammation manifested as atherosclerosis. Periodontal pathogens have been shown to contribute directly to atherosclerosis by disrupting endothelial cell function, one of the earliest indicators of cardiovascular disease. Oral infection is thought to indirectly induce elevated production of inflammatory mediators in the systemic circulation. Recently, a number of studies have been conducted focusing on how disruption of the gut microbiome influences the systemic production of proinflammatory cytokines and consequently exacerbation of inflammatory diseases such as atherosclerosis. It is clear that the immune mechanisms leading to atherosclerotic plaque progression, by oral infection, are complex. Understanding the immune pathways leading to disease progression is essential for the future development of anti-inflammatory therapies for this chronic disease.

Evidence for a vascular microbiome and its role in vessel health and disease

PURPOSE OF REVIEW

We have summarized available evidence for and against the presence of a vascular microbiome. Studies that have attempted to detect bacteria and viruses in blood vessels in both health and disease are critiqued in an attempt to explain contrary results that may be due to variations in methodology.

RECENT FINDINGS

Many studies have demonstrated the presence of both bacteria and viruses within diseased blood vessels. Evidence is most compelling in atherosclerosis; however, recent reports have raised questions about the potential role of microbes in nonatherosclerotic aortic aneurysms and vasculitis. Preliminary evidence also suggests that apparently normal vessels may harbor microbes. With the exception of certain viral infections (e.g. hepatitis C virus, HIV, Epstein-Barr virus, and cytomegalovirus) and infectious endocarditis, systemic vasculitides have not been convincingly associated with infectious agents. However, emerging data suggest that different communities of microbes may be present in noninflammatory and inflammatory large-vessel diseases. Whether variations in vascular microbial communities are the cause or a secondary result (epiphenomena) of vessel injury remains to be determined.

SUMMARY

Blood vessels may not be sterile. Future studies of microbes in vessel health and disease may provide important insights into disease pathogenesis and suggest new therapies for diseases now considered to be idiopathic and refractory.

Association of Chlamydia pneumoniae Infection With Atherosclerotic Plaque Formation

Atherosclerosis is a complex multifactorial disorder. Studies show that infectious microbial agents may play an important role in the development of atherosclerosis; however, these findings are conflicting. This study investigated the presence of Chlamydia pneumoniae DNA in atherosclerotic plaques of patients suffering from coronary artery disease. In a cross-sectional study, 85 patients (43 females and 42 males with mean age of 61±9.5, range 42-82 years) referred for coronary artery bypass grafting (CABG) and thoracic biopsy as the control groups were enrolled for this study. Standard questionnaires, including demographic and clinical evaluation were administered. Obtained specimens were processed and then nested polymerase chain reaction with primers for Pst1 fragment was carried out to detect Chlamydia pneumoniae DNA. Statistical analysis was done using the SPSS software. Of note, in 25 out of the 85 patients (29.4%), C. pneumoniae was detected within atherosclerotic plaques, whereas, 5 out of the 85 thoracic biopsy (5.9%) were positive for the presence of the mentioned bacteria in internal thoracic artery. There was a statistically significant association between atherosclerotic plaque (study group) and thoracic biopsy (control group) in terms of C. pneumoniae positivity (P=0.0001). The findings of this study support the hypothesis that C. pneumoniae is associated with atherosclerosis.

Microbial composition of atherosclerotic plaques

OBJECTIVE

The association of infections such as periodontitis with atherosclerotic diseases is well documented. In spite of the high diversity of the human oral microbiota, and its close contact with the circulatory system, few oral species were detected in atherosclerotic plaques. Thus, we attempted to evaluate the microbial diversity of atherosclerotic plaques from patients with different periodontal conditions, submitted to endarterectomy by a broad-range microbial method.

MATERIALS AND METHODS

Patients indicated for aorta endarterectomy due to myocardial infarction were recruited for periodontal clinical examination. The microbial diversity of atherosclerotic plaques (n = 35) was evaluated by sequence analysis of bacterial 16S rRNA libraries.

RESULTS

Bacterial DNA was detected in 12 endarterectomy specimens (34.3%). Twenty-three bacterial species/phylotypes were identified. Proteobacteria and Firmicutes comprised 78.3% and 21.7% of the identified taxa, respectively. Fifteen (60.9%) phylotypes were reported as yet uncultivable or as yet uncharacterized species. Two uncultured phylotypes were previously detected in the human mouth. The periodontopathogen Aggregatibacter actinomycetemcomitans was detected in seven samples (20%), followed by Pseudomonas species. There was no association between periodontal parameters and detection of A. actinomycetemcomitans or other phylotypes in atherosclerotic plaques.

CONCLUSION

Our results suggest a role of the oral microbiota in the development of inflammation in atherogenesis, particularly of A. actinomycetemcomitans.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Effects of Intravenous Injection of Porphyromonas gingivalis on Rabbit Inflammatory Immune Response and Atherosclerosis

The effects of intravenous injection of Porphyromonas gingivalis (Pg) on rabbit inflammatory immune response and atherosclerosis were evaluated by establishing a microamount Pg bacteremia model combined with high-fat diet. Twenty-four New Zealand rabbits were randomly divided into Groups A-D (n = 6). After 14 weeks, levels of inflammatory factors (C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1)) in peripheral blood were detected by ELISA. The aorta was subjected to HE staining. Local aortic expressions of toll-like receptor-2 (TLR-2), TLR-4, TNF-α, CRP, IL-6, matrix metallopeptidase-9, and MCP-1 were detected by real-time PCR, and those of nuclear factor-κB (NF-κB) p65, phospho-p38 mitogen-activated protein kinase (MAPK), and phospho-c-Jun N-terminal kinase (JNK) proteins were detected by Western blot. Intravenous injection of Pg to the bloodstream alone induced atherosclerotic changes and significantly increased systemic and local aortic expressions of inflammatory factors, NF-κB p65, phospho-p38-MAPK, and JNK, especially in Group D. Injection of microamount Pg induced inflammatory immune response and accelerated atherosclerosis, in which the NF-κB p65, p38-MAPK, and JNK signaling pathways played important roles. Intravenous injection of Pg is not the same as Pg from human periodontitis entering the blood stream. Therefore, our results cannot be extrapolated to human periodontitis.

An inverse association of Helicobacter pylori infection with oral squamous cell carcinoma

BACKGROUND

Few studies have focused on the relationship between Helicobacter pylori (H. pylori) infection and oral diseases. In this study, we explored the correlation between H. pylori infection and oral squamous cell carcinoma (OSCC).

METHODS

A total of 68 patients with OSCC and 104 age- and sex- matched healthy control subjects were retrospectively enrolled in this study. The H. pylori immunoglobin (Ig) G antibodies in serum were detected by enzyme-linked immunosorbent assay (ELISA) method to assess the status of H. pylori infection of our study sample. Polymerase chain reaction (PCR) was also employed using H. pylori genus-specific 16S rRNA primers in fasting blood, and OSCC specimens were analyzed by histochemical stain of each enrolled subject. The strength of correlation between H. pylori and the development of OSCC was estimated by Spearman's correlation coefficient.

RESULTS

According to the three methods for detecting prevalence of H. pylori infection in the patients with OSCC, it was statistically lower than that in the healthy controls (35.3% vs. 54.8%, P = 0.012). An inverse correlation was observed between H. pylori infection and OSCC development (Spearman's correlation coefficient = -0.191, P = 0.012). In stratification analysis, we also found a statistical association between H. pylori infection and OSCC in the subpopulation with age ≥ 60 years (P = 0.037).

CONCLUSION

Our findings suggested that H. pylori infection may be negatively related to OSCC. A reverse association of H. pylori infection with OSCC risk in the subpopulation with age ≥ 60 years was also found.

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.

Role of Helicobacter pylori infection in pathogenesis of atherosclerosis

Though a century old hypothesis, infection as a cause for atherosclerosis is still a debatable issue. Epidemiological and clinical studies had shown a possible association but inhomogeneity in the study population and study methods along with potential confounders have yielded conflicting results. Infection triggers a chronic inflammatory state which along with other mechanisms such as dyslipidemia, hyper-homocysteinemia, hypercoagulability, impaired glucose metabolism and endothelial dysfunction, contribute in pathogenesis of atherosclerosis. Studies have shown a positive relations between Cytotoxic associated gene-A positive strains of Helicobacter pylori and vascular diseases such as coronary artery disease and stroke. Infection mediated genetic modulation is a new emerging theory in this regard. Further large scale studies on infection and atherosclerosis focusing on multiple pathogenetic mechanisms may help in refining our knowledge in this aspect.

Association between Bacterial Infection and Peripheral Vascular Disease: A Review

There are an increasing number of data showing a clinically important association between bacterial infection and peripheral artery disease (PAD). Bacteria suspected of being involved in PAD pathogenesis are: periodontal bacteria, gut microbiota, Helicobacter pylori, and Chlamydia pneumoniae. Infectious agents may be involved in the pathogenesis of atherosclerosis via activation of a systemic or local host immunological response to contamination of extravascular tissues or the vascular wall, respectively. A systemic immunological reaction may damage vascular walls in the course of autoimmunological cross-reactions between anti-pathogen antibodies and host vascular antigens (immunological mimicry), pathogen burden mechanisms (nonspecific activation of inflammatory processes in the vascular wall), and neuroendocrine-immune cross-talk. Besides activating the inflammatory pathway, bacterial infection may trigger PAD progression or exacerbation by enhancement of platelet reactivity, by a stimulatory effect on von Willebrand factor binding, factor VIII, fibrinogen, P-selectin activation, disturbances in plasma lipids, increase in oxidative stress, and resistance to insulin. Local inflammatory host reaction and induction of atherosclerotic plaque progression and/or instability result mainly from atherosclerotic plaque colonization by microorganisms. Despite these premises, the role of bacterial infection in PAD pathogenesis should still be recognized as controversial, and randomized, controlled trials are required to evaluate the outcome of periodontal or gut bacteria modification (through diet, prebiotics, and probiotics) or eradication (using antibiotics) in hard and surrogate cardiovascular endpoints.

Danger signaling in atherosclerosis

All aspects of the pathogenesis of atherosclerosis are critically influenced by the inflammatory response in vascular plaques. Research in the field of innate immunity from the past 2 decades has uncovered many novel mechanisms elucidating how immune cells sense microbes, tissue damage, and metabolic derangements. Here, we summarize which triggers of innate immunity appear during atherogenesis and by which pathways they can contribute to inflammation in atherosclerotic plaques. The increased understanding gained from studies assessing how immune activation is associated with the pathogenesis of atherosclerosis has provided many novel targets for potential therapeutic intervention. Excitingly, the concept that inflammation may be the core of cardiovascular disease is currently being clinically evaluated and will probably encourage further studies in this area.

Infectious burden and atherosclerosis: A clinical issue

Atherosclerotic cardiovascular diseases, chronic inflammatory diseases of multifactorial etiology, are the leading cause of death worldwide. In the last decade, more infectious agents, labeled as “infectious burden”, rather than any single pathogen, have been showed to contribute to the development of atherosclerosis through different mechanisms. Some microorganisms, such as Chlamydia pneumoniae (C. pneumoniae), human cytomegalovirus, etc. may act directly on the arterial wall contributing to endothelial dysfunction, foam cell formation, smooth muscle cell proliferation, platelet aggregation as well as cytokine, reactive oxygen specie, growth factor, and cellular adhesion molecule production. Others, such as Helicobacter pylori (H. pylori), influenza virus, etc. may induce a systemic inflammation which in turn may damage the vascular wall (e.g., by cytokines and proteases). Moreover, another indirect mechanism by which some infectious agents (such as H. pylori, C. pneumoniae, periodontal pathogens, etc.) may play a role in the pathogenesis of atherosclerosis is molecular mimicry. Given the complexity of the mechanisms by which each microorganism may contribute to atherosclerosis, defining the interplay of more infectious agents is far more difficult because the pro-atherogenic effect of each pathogen might be amplified. Clearly, continued research and a greater awareness will be helpful to improve our knowledge on the complex interaction between the infectious burden and atherosclerosis.

Relationship between Helicobacter hepaticus infection and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a high incidence worldwide, with a low diagnostic rate in the early period and therefore a high death rate. Causes for some cases of liver cancer are not completely clear. The finding that the rate of liver cancer in male A/Jr mice is significantly higher makes researchers realize that Helicobacter hepaticus may cause HCC in human beings. To get a new perspective for exploring causes of liver cancer, this paper introduces the biological nature of and detecting methods for Helicobacter hepaticus, as well as the relationship between Helicobacter hepaticus infection and HCC. Helicobacter hepaticus infection may play an important role in some HCC cases.

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.

Atherosclerosis and Alzheimer--diseases with a common cause? Inflammation, oxysterols, vasculature

BACKGROUND

Aging is accompanied by increasing vulnerability to pathologies such as atherosclerosis (ATH) and Alzheimer disease (AD). Are these different pathologies, or different presentations with a similar underlying pathoetiology?

DISCUSSION

Both ATH and AD involve inflammation, macrophage infiltration, and occlusion of the vasculature. Allelic variants in common genes including APOE predispose to both diseases. In both there is strong evidence of disease association with viral and bacterial pathogens including herpes simplex and Chlamydophila. Furthermore, ablation of components of the immune system (or of bone marrow-derived macrophages alone) in animal models restricts disease development in both cases, arguing that both are accentuated by inflammatory/immune pathways. We discuss that amyloid β, a distinguishing feature of AD, also plays a key role in ATH. Several drugs, at least in mouse models, are effective in preventing the development of both ATH and AD. Given similar age-dependence, genetic underpinnings, involvement of the vasculature, association with infection, Aβ involvement, the central role of macrophages, and drug overlap, we conclude that the two conditions reflect different manifestations of a common pathoetiology.

MECHANISM

Infection and inflammation selectively induce the expression of cholesterol 25-hydroxylase (CH25H). Acutely, the production of 'immunosterol' 25-hydroxycholesterol (25OHC) defends against enveloped viruses. We present evidence that chronic macrophage CH25H upregulation leads to catalyzed esterification of sterols via 25OHC-driven allosteric activation of ACAT (acyl-CoA cholesterol acyltransferase/SOAT), intracellular accumulation of cholesteryl esters and lipid droplets, vascular occlusion, and overt disease.

SUMMARY

We postulate that AD and ATH are both caused by chronic immunologic challenge that induces CH25H expression and protection against particular infectious agents, but at the expense of longer-term pathology.

No detection of Helicobacter pylori in atherosclerotic plaques in end stage renal disease patients undergoing kidney transplantation

Chronic infection known to be a predisposing factor for the development of atherosclerosis. Several studies have found a possible role of Helicobacter pylori in the pathogenesis of atherosclerosis. The aim of this study was to investigate the presence of H. pylori in atherosclerotic plaques in iliac arteries in 25 end stage renal disease (ESRD) patients undergoing kidney transplantation. Esophagogastroduodenoscopy was performed in all patients before transplantation. Biopsy specimens obtained from gastric antrum were sent for pathologic evaluation. Gastric H. pylori infection was confirmed by microscopic assessment and rapid urease test. Arterial specimens were obtained from iliac arteries during kidney transplantation. Presence of H. pylori DNA in atherosclerotic plaques and healthy vessel samples was evaluated by the polymerase chain reaction (PCR). The mean age of patients was 44.1 ± 22.6 years. Risk factors in patients with atherosclerosis were hypertension (68%), diabetes mellitus (20%), hyperlipidemia (20%), positive family history (16%). Atherosclerotic plaques were found in 21 (84%) patients. PCR analysis did not detect H. pylori in any case. There was a significant relationship of atherosclerosis with hypertension (P = 0.006) but not with diabetes mellitus and hyperlipidemia (P = 0.5). There was no significant relationship between atherosclerosis and gastric H. pylori infection (P = 0.6). This study revealed no association between the presence of H. pylori as a pathogen of vessel walls and atherosclerosis in ESRD.

Relationship between Helicobacter pylori infection and serum interleukin-18 in patients with carotid atherosclerosis

BACKGROUND

Helicobacter pylori (H. pylori) infection stimulates the production of proinflammatory cytokines associated with the development of atherosclerosis. Levels of circulating interleukin-18 (IL-18) have been positively correlated with carotid intima-media thickness (IMT) and coronary plaque area and have identified IL-18 levels as important predictors of coronary events and cardiovascular mortality. This study aimed to examine the relationship between serum IL-18 and H. pylori-IgG antibody as a sign of H. pylori infection in patients with carotid atherosclerosis.

METHODS

The carotid IMT, traditional atherosclerotic risk factors, levels of serum H. pylori-IgG and IL-18 were measured in 573 health checkup examinees.

RESULTS

Serum IL-18 and H. pylori-IgG levels were significantly increased in subjects with increased IMT in comparison with those with normal IMT. In subjects with increased IMT, serum H. pylori-IgG was positively correlated with serum IL-18 (r = .402, p = .002), and the association was independent of traditional atherosclerotic risk factors (β = 0.310, p < .001).

CONCLUSIONS

In health checkup examinees with increased IMT, serum IL-18 and H. pylori-IgG were independently correlated and were significantly higher than in subjects with normal IMT.

Atherosclerosis and infection: is the jury still not in?

Atherosclerosis is a chronic inflammatory process accounting for increased cardiovascular and cerebrovascular morbidity and mortality. A wealth of recent data has implicated several infectious agents, mainly Chlamydophila pneumoniae, Helicobacter pylori, CMV and periodontal pathogens, in atherosclerosis. Thus, we sought to comprehensively review the available data on the topic, exploring in particular the pathogenetic mechanisms, and discuss anticipated future directions.

A retrospective study of AIDS-associated cryptomeningitis

Cryptococcal meningitis has emerged as a leading cause of infectious morbidity and mortality in patients with AIDS. A retrospective analysis of records of HIV-infected individuals registered in the Immunodeficiency Clinic of a tertiary care hospital and research institute was carried out. Records of 6900 HIV-infected individuals who were enrolled in the clinic between January 2002 and March 2011 were analyzed. Records of 6900 HIV-infected individuals were screened. Ninety-one were diagnosed with cryptococcal meningitis (1.32%). In 68 individuals cryptococcal meningitis was the presenting illness. Nine patients developed meningitis within 6 months of starting antiretroviral treatment (ART). Six patients were receiving ART for more than 6 months at the time of diagnosis. The remaining eight patients were not on ART at the time of development of meningitis. The mean baseline CD4 count of patients was 77.7 ± 61 (range, 4-259, n=91) cells/mm(3). Seventy-four patients had a CD4 value of less than 100 at the time of diagnosis of cryptococcal meningitis. Eleven of these ninety-one patients had a relapse of cryptococcal meningitis while receiving a maintenance dose of fluconazole. During follow-up 37 died, two were lost to follow-up, while 52 patients were on regular ART. Mortality due to cryptococcal meningitis amounted to 0.54% (37/6900). There was no correlation between survival and duration of ART at the time of cryptomeningitis (Pearsons χ(2)=0.241, p=0.884). There was a significant difference in the CD4 counts of the HIV-infected individuals who died with cryptomeningitis and those who survived (Pearson's χ(2)=9.1, df=4, p=0.05). The frequency of cryptococcal meningitis was 1.32%. Cryptococcal meningitis leads to high mortality in HIV patients. Management of cryptococcal infection remains a key facet of AIDS care in India.

Pathogens and atherosclerosis: update on the potential contribution of multiple infectious organisms to the pathogenesis of atherosclerosis

It is currently unclear what causes the chronic inflammation within atherosclerotic plaques. One emerging paradigm suggests that infection with bacteria and/or viruses can contribute to the pathogenesis of atherosclerosis either via direct infection of vascular cells or via the indirect effects of cytokines or acute phase proteins induced by infection at non-vascular sites. This paradigm has been supported by multiple epidemiological studies that have established positive associations between the risk of cardiovascular disease morbidity and mortality and markers of infection. It has also been supported by experimental studies showing an acceleration of the development of atherosclerosis following infection of hyperlipidaemic animal models. There are now a large number of different infectious agents that have been linked with an increased risk of cardiovascular disease. These include: Chlamydia pneumoniae, Porphyromonas gingivalis, Helicobacter pylori , influenza A virus, hepatitis C virus, cytomegalovirus, and human immunodeficiency virus. However, there are significant differences in the strength of the data supporting their association with cardiovascular disease pathogenesis. In some cases, the infectious agents are found within the plaques and viable organisms can be isolated suggesting a direct effect. In other cases, the association is entirely based on biomarkers. In the following review, we evaluate the strength of the data for individual or groups of pathogens with regard to atherosclerosis pathogenesis and their potential contribution by direct or indirect mechanisms and discuss whether the established associations are supportive of the infectious disease paradigm. We also discuss the failure of antibiotic trials and the question of persistent infection.

Association of Helicobacter pylori infection with acute myocardial infarction

OBJECTIVES

Helicobacter pylori infection has been linked to cardiovascular diseases (CVD) and several studies have reported its positive association with inflammatory response after acute myocardial infarction (AMI). On account of the importance of the inflammatory process in the development of CVD, we decided to examine the seroprevalence of H. pylori, the prevalence of CVD risk in the more virulent strains bearing the cytotoxin-associated protein (CagA), and the changes in C-reactive protein (CRP) as an inflammatory marker in Iranian patients with AMI.

METHODS

A case-control study was designed to determine the seropositivity status of H. pylori and CagA in blood samples obtained from 500 patients with AMI and 500 control individuals without any evidence of clinical CVD. Serum and peripheral blood mononuclear cells were analyzed using the enzyme-linked immunosorbent assay and western blotting methods, respectively. CRP levels were also measured in all individuals.

RESULTS

The prevalence of H. pylori infection and CagA status were significantly higher among the patients with AMI than the controls (66 vs. 20% and 75.7 vs. 30%, respectively); the odds ratio was 2.57 (95% confidence interval 1.89-3.49). CRP levels were significantly different in the patients compared with the controls (5.02±1.04 mg/l vs. 2.41±0.9 mg/l, respectively).

CONCLUSION

Our results confirmed that the patients with AMI had a significantly higher prevalence of H. pylori infection and CagA seropositivity than the control population. Infection with H. pylori may influence AMI, which in our findings shows an association between H. pylori seropositivity and AMI through an inflammatory process.

Porphyromonas gingivalis-dendritic cell interactions: consequences for coronary artery disease

An estimated 80 million US adults have one or more types of cardiovascular diseases. Atherosclerosis is the single most important contributor to cardiovascular diseases; however, only 50% of atherosclerosis patients have currently identified risk factors. Chronic periodontitis, a common inflammatory disease, is linked to an increased cardiovascular risk. Dendritic cells (DCs) are potent antigen presenting cells that infiltrate arterial walls and may destabilize atherosclerotic plaques in cardiovascular disease. While the source of these DCs in atherosclerotic plaques is presently unclear, we propose that dermal DCs from peripheral inflamed sites such as CP tissues are a potential source. This review will examine the role of the opportunistic oral pathogen Porphyromonas gingivalis in invading DCs and stimulating their mobilization and misdirection through the bloodstream. Based on our published observations, combined with some new data, as well as a focused review of the literature we will propose a model for how P. gingivalis may exploit DCs to gain access to systemic circulation and contribute to coronary artery disease. Our published evidence supports a significant role for P. gingivalis in subverting normal DC function, promoting a semimature, highly migratory, and immunosuppressive DC phenotype that contributes to the inflammatory development of atherosclerosis and, eventually, plaque rupture.

Acute ischemic stroke and infections

We present an overview of multiple infections in relation to acute ischemic stroke and the therapeutic options available. Conditions that are a direct cause of stroke (infectious endocarditis, meningoencephalitides, and human immunodeficiency virus infection), the pathophysiologic mechanism responsible for stroke, and treatment dilemmas are presented. Independently or in conjunction with conventional risk factors, chronic and acute infections can trigger an acute ischemic stroke through an accelerated process of atherosclerosis and immunohematologic alterations. Acute ischemic stroke has a negative impact on the antibacterial immune response, leading to stroke-induced immunodepression and infections, the most common poststroke medical complications. Poststroke infections are independent predictors of poor outcome. Antibiotic trials for poststroke infection prevention are reviewed. Although antibiotic prophylaxis is not the standard of care in acute stroke, current guidelines support prompt treatment of stroke-related infections.

Mycotic DNA in non-atherosclerotic aortic wall of coronary patients is associated with sICAM-1 expression

BACKGROUND

Atherosclerosis is currently being investigated as a chronic inflammatory process and the role of infectious agents is unclear. The presence of mycotic DNA in the wall of the non-atherosclerotic aorta of patients with coronary artery disease (CAD) and its association with levels of soluble intercellular adhesion molecule (sICAM)-1 expression was examined in the present study.

METHODS AND RESULTS

In 40 patients with CAD and a comparative group of 20 patients with aortic valve stenosis (AS) without CAD, specimens of the aortic wall were obtained during cardiac surgery. Mycotic DNA was analyzed by polymerase chain reaction (PCR) using a fungus-specific universal primer pair, ITS3 and ITS4, to amplify a portion of the 5.8S rDNA region, the entire ITS2 region and a portion of the 28S rDNA region, and using a species-specific primer pair, CALB1 and CALB2, to specifically amplify Candida (C.) albicans. The nested PCR method was performed to amplify the intergenic transcribed spacer regions of the rRNAs of Candida species. Before surgery the serum level of sICAM-1 was estimated. Mycotic DNA was detected in 48% of the CAD patients and in 40% of the AS patients, with C. albicans DNA in 58% and 100%, respectively (P>0.05). In CAD patients with a high level of sICAM-1, C. albicans DNA was found more frequently than in patients without elevated levels of sICAM-1 (P<0.05).

CONCLUSIONS

Mycotic DNA was found in the non-atherosclerotic aortic wall of CAD patients as well as in patients with AS. In the CAD patients C. albicans DNA was related to sICAM-1 expression.

Helicobacter pylori infection is associated with decreased serum levels of high density lipoprotein, but not with the severity of coronary atherosclerosis

OBJECTIVE

The objective of this survey was to study the association between Helicobacter pylori infection and the severity of coronary atherosclerosis.

METHODS

The study population consisted of 961 consecutive patients (711 males and 250 females) who underwent coronary angiography for suspected or known coronary atherosclerosis. The patients' body mass index, blood pressure, the blood lipid, blood glucose, leukocyte count (10(9)/L), neutrophil count (10(9)/L), and Helicobacter pylori-specific IgG antibodies were performed. Coronary angiograms were scored according to vessel score and Gensini's score.

RESULTS

A significant association between H. pylori infection and coronary atherosclerosis as well as its severity was not find in this cross section study (p = 0.858). And, the level distribution of vessel score (p = 0.906) and Gensini's score (p = 0.905) were similar in the seropositivity group and seronegativity group of Helicobacter pylori infection. However, the level of fasting high-density lipoprotein cholesterol (mmol/L) (p = 0.013) was significantly lower in the seropositivity group than that in the seronegativity group of Helicobacter pylori infection.

CONCLUSIONS

In conclusion, in the present study, a significantly correlation between Helicobacter pylori seropositivity and angiographically evaluated severity of atherosclerosis was not find. And, the present study showed a good correlation between Helicobacter pylori infection and decreased HDL cholesterol. However, the exact mechanisms need further study.

Helicobacter pylori seropositivity in patients with acute coronary syndromes

The aim of this study was to investigate the seroprevalence of Helicobacter pylori (HP) in patients with coronary atherosclerosis and acute coronary syndromes. We enrolled 152 patients (group I, 73 patients with acute coronary syndrome; group II, 79 patients with chronic stable angina) and 22 control subjects. An enzyme-linked immunosorbent assay for immunoglobulin (Ig) G test for HP diagnosis was used on all enrolled subjects. C-reactive protein (CRP) was also measured in all patients as an inflammatory marker. Seropositivity rates for HP were significantly higher in patients with coronary artery disease than in controls (80.2% versus 54.5%; P < 0.05). Although CRP level was significantly higher in group I than in group II (1.72 +/- 2.89 mg/dl versus 0.53 +/- 0.63 mg/dl, P < 0.0001), HP infection rates were similar between groups (86.3% versus 74.6%, P > 0.05). Infection with HP may influence atherogenesis through low-grade, persistent inflammatory stimulation. However, our data show evidence of increased systemic inflammation in patients with acute coronary syndrome, which was unrelated to an increased HP seropositivity.