Chlamydia pneumoniae burden in carotid arteries is associated with upregulation of plaque interleukin-6 and elevated C-reactive protein in serum

Liver Fibrosis and Hearing Loss in an Older Mediterranean Population: Results from the Salus in Apulia Study

Background: Aging is the main negative prognostic factor for various chronic diseases, such as liver fibrosis, and clinical disorders such as hearing loss. This study aimed to investigate the association between age-related hearing loss (ARHL) and age-related central auditory processing disorder (CAPD), and the risk for liver fibrosis in a cross-sectional study on an aging population. Methods: Liver fibrosis risk was judged on the fibrosis-4 (FIB-4) score. Peripheral ARHL was evaluated with pure tone audiometry using a calibrated audiometer. The pure tone average (PTA), calculated as a threshold ≤ 40 dB (HL) in the better ear, was measured at the frequencies 0.5−4 kHz. For age-related CAPD assessment, we employed the Synthetic Sentence Identification with an Ipsilateral Competitive Message test (SSI-ICM). General linear Logistic regression models were used to estimate the association. Results: The increase in the PTA 0.5−2 kHz (coefficient: 0.02, SE: 0.01, CI 95%: 0.01 to 0.03) was directly associated with a higher risk of liver fibrosis (FIB-4 ≥ 2.67). Moreover, the reduction in SSI (coefficient: −0.02, SE: 0.01, CI 95%: −0.03 to −0.01) was inversely associated with FIB-4 values < 2.67. Conclusion: Our results show an association between liver fibrosis and both ARHL and CAPD, linked by the typical consequence of aging. We also assume a role of inflammatory responses and oxidative stress.

Relationship of Streptococcus mutans with valvar cardiac tissue: A molecular and immunohistochemical study

BACKGROUND

The present study aimed to investigate the presence or absence of Streptococcus mutans in oral cavity and valvular samples associating with the histomorphologic alterations of calcified aortic stenosis.

METHODOLOGY

Dental plaque and cardiac valve samples were collected from 10 patients with calcified aortic stenosis for molecular analysis of S mutans by real-time polymerase chain reaction (PCR). Healthy valve tissue was also collected from five young cadavers and analyzed for S mutans. Moreover, fragments of all valvar specimens were submitted for histomorphological analysis and immunohistochemistry (anti-S mutans and anti-CD61).

RESULTS

Streptococcus mutans was present in 100% of the oral cavity samples from the patients with calcified aortic stenosis in the molecular analysis. The analysis by real-time PCR showed that S mutans presented the same proportion in healthy valves and those with calcified aortic stenosis (80%; P = 1.000). Conversely, the immunoexpression of S mutans was 37.40 (IC95% = 1.49-937.00) times superior in samples of patients with cardiac disease (P = .007). The immunoexpression analysis showed that CD61 was present in seven (70%) calcified aortic stenosis samples, all of which were also immunopositive for S mutans.

CONCLUSIONS

Streptococcus mutans was found in the oral cavity, healthy valve tissue, and calcified aortic stenosis samples. However, the microorganism was visualized by immunohistochemistry only in the calcified aortic stenosis samples, which may suggest viability and an increased bacterial density in this condition. The association of the presence of S mutans and positive CD61 immunoexpression suggests a probable relationship with calcified aortic stenosis.

Neck vein obstruction: Diagnosis and the role of chronic persistent Chlamydophila pneumoniae infection

Background

The objective of this review is to describe the diagnosis of neck vein obstruction and the possible role of chronic persistent Chlamydophila pneumoniae infection in producing the syndrome of chronic cerebrospinal venous obstruction.

Method

The normal patterns of flow in the neck veins are described and guidelines for interpretation of the quantitative duplex ultrasound examination of the extracranial neck veins are developed.

Result

An infective cause of neck vein obstruction is proposed and from a literature search of the role of the obligate intracellular bacterium Chlamydophila pneumoniae in vascular and chronic diseases, a diagnostic protocol for confirming chronic persistent Chlamydophila pneumoniae infection, which includes the quantitative duplex ultrasound examination and specific blood tests are suggested.

Conclusion

Further research to validate this diagnostic protocol is required.

Color M-mode echocardiography-derived propagation velocity of descending aorta decreases with aging

Background

Arterial stiffness (AS) can be determined by some noninvasive tests such as pulse wave velocity (PWV). Atherosclerosis is also detectable by some ultrasonographic techniques such as color M-mode-derived propagation velocity measured along the origin of the descending aorta (AVP).

Aim

The aim of the study was to find out a possible relationship between atherosclerosis and AVP and whether AVP can be used as a parameter of AS.

Materials and methods

The study group was composed of 134 people from routine screening examination who were ≥40 years old, completely healthy, and without any known disease and use of any drug. PWV has been determined to show aortic stiffness, and carotid artery intima– media thickness (CIMT) was measured for subclinical atherosclerosis. AVP values were obtained from all participants, and correlations were calculated between these parameters and age.

Results

AVP decreased (r=−0.902, P<0.001) and PWV increased (r=0.854, P<0.001) significantly with increasing age. CIMT also increased with aging (r=0.518, P<0.001). There were significant correlations between AVP and PWV (r=−0.832, P<0.001) and AVP and CIMT (r=−0.345, P<0.001).

Conclusion

Transthoracic echocardiographic determination of AVP can be used as a simple measurement of AS and correlates well with PWV, age, and CIMT in healthy people.

Research Progress on the Risk Factors and Outcomes of Human Carotid Atherosclerotic Plaques

Objective:

Atherosclerosis is an inflammatory process that results in complex lesions or plaques that protrude into the arterial lumen. Carotid atherosclerotic plaque rupture, with distal atheromatous debris embolization, causes cerebrovascular events. This review aimed to explore research progress on the risk factors and outcomes of human carotid atherosclerotic plaques, and the molecular and cellular mechanisms of human carotid atherosclerotic plaque vulnerability for therapeutic intervention.

Data Sources:

We searched the PubMed database for recently published research articles up to June 2016, with the key words of “risk factors”, “outcomes”, “blood components”, “molecular mechanisms”, “cellular mechanisms”, and “human carotid atherosclerotic plaques”.

Study Selection:

The articles, regarding the latest developments related to the risk factors and outcomes, atherosclerotic plaque composition, blood components, and consequences of human carotid atherosclerotic plaques, and the molecular and cellular mechanisms of human carotid atherosclerotic plaque vulnerability for therapeutic intervention, were selected.

Results:

This review described the latest researches regarding the interactive effects of both traditional and novel risk factors for human carotid atherosclerotic plaques, novel insights into human carotid atherosclerotic plaque composition and blood components, and consequences of human carotid atherosclerotic plaque.

Conclusion:

Carotid plaque biology and serologic biomarkers of vulnerability can be used to predict the risk of cerebrovascular events. Furthermore, plaque composition, rather than lesion burden, seems to most predict rupture and subsequent thrombosis.

Unraveling the environmental and genetic interactions in atherosclerosis: Central role of the gut microbiota

Recent studies have convincingly linked gut microbiota to traits relevant to atherosclerosis, such as insulin resistance, dyslipidemia and inflammation, and have revealed novel disease pathways involving microbe-derived metabolites. These results have important implications for understanding how environmental and genetic factors act together to influence cardiovascular disease (CVD) risk. Thus, dietary constituents are not only absorbed and metabolized by the host but they also perturb the gut microbiota, which in turn influence host metabolism and inflammation. It also appears that host genetics helps to shape the gut microbiota community. Here, we discuss challenges in understanding these interactions and the role they play in CVD.

Correlation of high-sensitivity C-reactive protein and carotid plaques with coronary artery disease in elderly patients

The aim of this study was to explore the correlation of high-sensitivity C-reactive protein (hs-CRP) and carotid plaques with the severity of coronary artery disease (CAD). A total of 140 patients with angina who underwent coronary angiography were selected and divided into a single-vessel disease group (n=11), double-vessel disease group (n=18), multi-vessel disease group (n=71) and control group (n=40). Color Doppler ultrasound was applied to measure the intima-media thickness (IMT) of the common carotid artery (CCA) and carotid bifurcation, and to record the location and number of carotid plaques. The serum hs-CRP level was also determined. Compared with the control and single-vessel disease groups, the multi-vessel disease group showed significantly higher IMT of the CCA (P<0.05). The serum hs-CRP level was highest in the multi-vessel disease group (P<0.01). The hs-CRP level and carotid plaque characteristics were found to correlate closely with the severity of CAD. Therefore, they may be used to improve the prediction of CAD severity in elderly patients.

Recombinant Cpn 0810 stimulates proinflammatory cytokine expression and apoptosis in human monocytes

The aim of the present study was to express the recombinant Chlamydophila pneumoniae (C. pneumoniae) protein, Cpn 0810, in Escherichia coli (E. coli) BL21, and investigate the effects of Cpn 0810 on inflammatory and apoptotic processes in human monocytic (THP-1) cells. An ELISA was performed to detect the levels of the proinflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-6. In addition, Hoechst 33258 staining and annexin V binding analyses were performed to measure the rates of apoptosis. Purified glutathione S-transferase (GST)-Cpn 0810 recombinant proteins were obtained from the E. coli BL21 cells carrying the pGEX6p-2/Cpn 0810 plasmid, and were shown to stimulate the expression of TNF-α and IL-6 in the THP-1 cells in a dose- and time-dependent manner. TNF-α and IL-6 levels peaked at 24 h after GST-Cpn 0810 stimulation. Furthermore, GST-Cpn 0810 significantly promoted the apoptosis of THP-1 cells. In conclusion, recombinant GST-Cpn 0810 was shown to stimulate the expression of TNF-α and IL-6, inhibit proliferation and induce apoptosis in THP-1 cells. Therefore, Cpn 0810 may interact with host cells following C. pneumoniae infection, functioning as an important pathogenic factor.

Effects of hyperbaric oxygen and dexamethasone on proinflammatory cytokines of rat cochlea in noise-induced hearing loss

HYPOTHESIS

To investigate effects of dexamethasone and hyperbaric oxygen therapy (HBOT) on proinflammatory cytokines and hearing levels in the noise-exposed cochlea of rats.

BACKGROUND

There is an arising concern about negative effects of early initiation of HBOT on hearing in noise-induced hearing loss. Furthermore, effects of HBOT and dexamethasone on cochlear cytokines are not fully elucidated.

METHODS

Twenty-six rats were divided into 3 groups: control, noise, and treatment groups. Five rats served as control group. White noise at 115 dB sound pressure level was applied to the noise group of 4 rats for 10 days. This group was assigned to a positive control group as it was equivalent to treatment groups. The treatment group of 17 rats underwent the same noise exposure, and then, they were divided into 3 groups based on treatment protocol: 5 and 6 rats received HBOT at the third hour and 24th hour after the noise, respectively, and 6 rats received dexamethasone. Auditory brain stem response threshold was measured in all groups before being assigned to the groups, after the noise exposure and right before being killed. Cytokine levels at the cochlear soft tissues were measured using enzyme-linked immunoassay.

RESULTS

Final thresholds (10 dB and 5 dB nHL-normal hearing level) of HBOT-24th hour and dexamethasone groups were significantly better than that of untreated noise group (22.5 dB nHL) (p < 0.05). There was no significant difference between HBOT-24th hour group (10 dB nHL) and dexamethasone group (5 dB nHL) (p > 0.05). IL-6 and IL-1β of HBOT-third hour group (2.30 ng/mg and 185.43 pg/mg) were significantly higher than those of the noise group (0.91 ng/mg and 131.40 pg/mg), dexamethasone group (1.19 ng/mg and 112.29 pg/mg) and HBOT-24th hour group (1.34 ng/mg and 106.69 pg/mg) (p < 0.05). There was no significant difference in IL-6 and IL-1β of HBOT-24th hour group, dexamethasone group, noise group, and control group (p > 0.05). There was no significant difference in TNF-α of the 3 treatment groups, noise group, and control group (p > 0.05).

CONCLUSION

The results showed that the most effective method in the treatment of noise-induced hearing loss was early initiation of dexamethasone therapy. There could be negative effects of HBOT on hearing if it is commenced early after the noise (first 3 h). HBOT treatment, which was started at the 24th hour, was found to be an effective method.

Association between MIF gene polymorphisms and carotid artery atherosclerosis

Atherosclerosis is a chronic inflammatory disorder. Macrophage migration inhibitory factor (MIF) is a potent cytokine that plays an important role in the regulation of immune responses. Polymorphisms including five- to eight-repeat CATT variants ((CATT)(5-8)) and G-173C in the promoter region of the MIF gene are associated with altered levels of MIF gene transcription. The purpose of the study is to investigate the relationship between promoter polymorphisms of the MIF gene and the severity of carotid artery atherosclerosis (CAA). The severity of CAA was assessed in 593 individuals with a history of ischemic stroke by using sonographic examination, and the MIF promoter polymorphisms of these individuals were genotyped. The carriage of (CATT)7 (compared to genotypes composed of (CATT)5, (CATT)6, or both), carriage of C allele (compared to GG), and carriage of the haplotype (CATT)7-C (compared to genotypes composed of (CATT)5-G, (CATT)6-G, or both) were significantly associated with an increase in the severity of CAA. We conclude that polymorphisms in the MIF gene promoter are associated with CAA severity in ischemic stroke patients. These genetic variants may serve as markers for individual susceptibility to CAA.

Vascular effects of glycoprotein130 ligands--part I: pathophysiological role

The vessel wall is no longer considered as only an anatomical barrier for blood cells but is recognized as an active endocrine organ. Dysfunction of the vessel wall occurs in various disease processes including atherosclerosis, hypertension, peripheral artery disease, aneurysms, and transplant and diabetic vasculopathies. Different cytokines were shown to modulate the behavior of the cells, which constitute the vessel wall such as immune cells, endothelial cells and smooth muscle cells. Glycoprotein 130 (gp130) is a common cytokine receptor that controls the activity of a group of cytokines, namely, interleukin (IL)-6, oncostatin M (OSM), IL-11, ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), cardiotrophin-1 (CT-1), cardiotrophin-like cytokine (CLC), IL-27, and neuropoietin (NP). Gp130 and associated cytokines have abundantly diverse functions. Part I of this review focuses on the pathophysiological functions of gp130 ligands. We specifically describe vascular effects of these molecules and discuss the respective underlying molecular and cellular mechanisms.

Association of Atherosclerosis With Expression of the LILRB1 Receptor By Human NK and T-Cells Supports the Infectious Burden Hypothesis

Objective—

The contribution of human cytomegalovirus (HCMV) to vascular disease may depend on features of the immune response not reflected by the detection of specific antibodies. Persistent HCMV infection in healthy blood donors has been associated with changes in the distribution of NK cell receptors (NKR). The putative relationship among HCMV infection, NKR distribution, subclinical atherosclerosis, and coronary heart disease was assessed.

Methods and Results—

NKR expression was compared in acute myocardial infarction (AMI) patients ( n =70) and a population-based control sample ( n =209). The relationship between NKR expression and carotid intima-media thickness (CIMT) in controls ( n =149) was also studied. HCMV infection was associated with higher proportions of NKG2C+ and LILRB1+ NK and T-cells. In contrast, only LILRB1+ NK and CD56+ T-cells were found to be increased in AMI patients, independent of age, sex, conventional vascular risk factors, and HCMV seropositivity. Remarkably, LILRB1 expression in NK and T-cells significantly correlated with CIMT in controls.

Conclusion—

The association of overt and subclinical atherosclerotic disease with LILRB1+ NK and T-cells likely reflects a relationship between the immune challenge by infections and cardiovascular disease risk, without attributing a dominant role for HCMV. Our findings may lead to the identification of novel biomarkers of vascular disease.

Periodontal disease and hypertriglyceridemia in Japanese subjects: potential association with enhanced lipolysis

Although periodontal disease may be associated with increased risk for atherosclerosis, the mechanism by which the disease causes atherosclerosis is still unknown. The candidates contributing to atherosclerosis in periodontal disease include low-grade inflammation such as C-reactive protein (CRP) and insulin resistance. A previous study demonstrated that periodontal therapy leads to an improvement in CRP as well as insulin resistance, indicating the relationship between periodontal disease and low-grade inflammation or insulin resistance. On the other hand, we previously demonstrated that serum triglyceride (TG) per se is independently associated with CRP or insulin resistance in Japanese populations with a body mass index (BMI) of 21.5 to 27.0 (midrange BMI). To the best of our knowledge, however, the relationship between periodontal disease and serum TG is not fully clarified. The first aim of the present study is to investigate whether periodontal disease is associated with serum TG in Japanese subjects with midrange BMI. If so, another aim of the study is to determine which mechanism is responsible for the association between periodontal disease and serum TG in these subjects. We have performed a periodontal examination in the Ogaki metabolic syndrome medical examination. One hundred sixty-two participants from 40 to 74 years old (56 men and 106 women; mean age, 66.43 ± 6.25 years) were enrolled in the study. Besides medical examination, oral panoramic radiograph was taken for all participants. Average bone score was also calculated. Periodontal bone destruction increased according to the age of the participants (r = 0.227, P < .004, Spearman correlation coefficient). Periodontal bone destruction was also associated with serum TG levels (r = 0.299, P = .000). This association was more evident in subjects with midrange BMI (r = 0.332, P < .001). In subjects with midrange BMI, TG was not correlated with BMI or waste circumstances. Furthermore, TG was not associated with age itself in the midrange BMI group. We then investigated the lipolytic activity of endotoxin in cocultures of adipocytes and macrophages. Low-dose lipopolysaccharide dose-dependently increased lipolytic activity in cocultures, and this activity was neutralized by anti-tumor necrosis factor α neutralizing antibodies. These results suggest that periodontal infection, especially bacterial endotoxinemia, is associated with enhanced lipolysis and subsequent up-regulation of circulating TG in Japanese with midrange BMI.

Qualitative and quantitative detection of agricultural microorganisms expressing iturin and mop cyclase in soils

The environmental release of genetically engineered microorganisms (GEMs) to improve agriculture or remediate environmental hazards has raised concern over the fate of the organisms and their engineered genes. To detect the microorganisms released into the environment at the molecular level, Bacillus subtilis KB producing iturin and Pseudomonas fluorescens MX1 carrying the moc (mannityl opine catabolism) region from the Agrobacterium tumefaciens were employed as model microorganisms. Using specific fusion primers and the TaqMan probes, qualitative and quantitative detections of the model organisms by PCR and real-time PCR were conducted employing a small-scale soil-core device and pots during the six month period. The data indicate that the model bacteria can be easily detected by qualitative and quantitative methods in the test systems employed, and they do not give significant impacts on the other bacteria in soils on the Southern blotting analysis, although long-term observation may be needed.

Association of carotid plaque Lp-PLA(2) with macrophages and Chlamydia pneumoniae infection among patients at risk for stroke

Background

We previously showed that the burden of Chlamydia pneumoniae in carotid plaques was significantly associated with plaque interleukin (IL)-6, and serum IL-6 and C-reactive protein (CRP), suggesting that infected plaques contribute to systemic inflammatory markers in patients with stroke risk. Since lipoprotein-associated phospholipase A2 (Lp-PLA₂) mediates inflammation in atherosclerosis, we hypothesized that serum Lp-PLA₂ mass and activity levels and plaque Lp-PLA₂ may be influenced by plaque C. pneumoniae infection.

Methodology/Principal Findings

Forty-two patients underwent elective carotid endarterectomy. Tissue obtained at surgery was stained by immunohistochemistry for Lp-PLA₂ grade, macrophages, IL-6, C. pneumoniae and CD4+ and CD8+ cells. Serum Lp-PLA₂ activity and mass were measured using the colorimetric activity method (CAM™) and ELISA, respectively. Serum homocysteine levels were measured by HPLC. Eleven (26.2%) patients were symptomatic with transient ischemic attacks. There was no correlation between patient risk factors (smoking, coronary artery disease, elevated cholesterol, diabetes, obesity, hypertension and family history of genetic disorders) for atherosclerosis and serum levels or plaque grade for Lp-PLA₂. Plaque Lp-PLA₂ correlated with serum homocysteine levels (p = 0.013), plaque macrophages (p<0.01), and plaque C. pneumoniae (p<0.001), which predominantly infected macrophages, co-localizing with Lp-PLA₂.

Conclusions

The significant association of plaque Lp-PLA₂ with plaque macrophages and C. pneumoniae suggests an interactive role in accelerating inflammation in atherosclerosis. A possible mechanism for C. pneumoniae in the atherogenic process may involve infection of macrophages that induce Lp-PLA₂ production leading to upregulation of inflammatory mediators in plaque tissue. Additional in vitro and in vivo research will be needed to advance our understanding of specific C. pneumoniae and Lp-PLA₂ interactions in atherosclerosis.

The acute phase reactant response to respiratory infection with Chlamydia pneumoniae: implications for the pathogenesis of atherosclerosis

The acute phase response to Chlamydia pneumoniae infection was analyzed over a 72 h period post-infection in C57BL/6J mice. A single intra-nasal inoculation stimulated statistically significant increases in the plasma levels of IL-2, IL-5, IL-6, IL-10, IL-12, GM-CSF, IFN-gamma, and serum amyloid A but not TNF-alpha, IL-1beta, IL-4 and serum amyloid P. There was also a decrease in the activity of the HDL protective enzyme paraoxonase as well as a reduced ability of HDL to prevent oxidation of palmitoyl-2-arachidonyl-sn-glycerol-3-phosphocholine by hydroperoxyoctadecadienoic acid at 48 and 72 h post-infection. To determine whether the C. pneumoniae induced acute phase response had any effect on atherosclerotic plaque stability, we measured the frequency of intra-plaque hemorrhage as a marker of plaque disruption in the innominate arteries of apolipoprotein E deficient mice at 29-30 weeks and 1.5-2.0 years of age. There was an increased frequency of intra-plaque hemorrhage only in the older mice infected with the live organism (8/14) as compared to mice treated with killed C. pneumoniae (2/11) or sham inoculated with PBS (2/12). These results suggest that acute phase reactant proteins produced in response to pulmonary infection with C. pneumoniae may contribute to the progression and destabilization of atherosclerotic lesions.

Blockade of interleukin-6 signaling suppressed cochlear inflammatory response and improved hearing impairment in noise-damaged mice cochlea

Hearing impairment can be the cause of serious socio-economic disadvantages. Recent studies have shown inflammatory responses in the inner ear co-occur with various damaging conditions including noise-induced hearing loss. We reported pro-inflammatory cytokine interleukin-6 (IL-6) was induced in the cochlea 6h after noise exposure, but the pathophysiological implications of this are still obscure. To address this issue, we investigated the effects of IL-6 inhibition using the anti-IL-6 receptor antibody (MR16-1). Noise-exposed mice were treated with MR16-1 and evaluated. Improved hearing at 4kHz as measured by auditory brainstem response (ABR) was noted in noise-exposed mice treated with MR16-1. Histological analysis revealed the decrease in spiral ganglion neurons was ameliorated in the MR16-1-treated group, while no significant change was observed in the organ of Corti. Immunohistochemistry for Iba1 and CD45 demonstrated a remarkable reduction of activated cochlear macrophages in spiral ganglions compared to the control group when treated with MR16-1. Thus, MR16-1 had protective effects both functionally and pathologically for the noise-damaged cochlea primarily due to suppression of neuronal loss and presumably through alleviation of inflammatory responses. Anti-inflammatory cytokine therapy including IL-6 blockade would be a feasible novel therapeutic strategy for acute sensory neural hearing loss.

Chlamydia pneumoniae IgA and elevated level of IL-6 may synergize to accelerate coronary artery disease

OBJECTIVES

A strong association of cytokines [interleukin (IL)-6, IL-2 and tumor necrosis factor (TNF)-alpha] with atherosclerosis is well documented. However, their role in Chlamydia pneumoniae (Cp)-associated progression of coronary artery disease (CAD) is not well studied. Hence we evaluated the presence of these cytokines in CAD patients positive for Cp immunoglobulin (Ig) A (low, medium, and high levels) CAD and compared with controls. Also the physiological and baseline characteristics in IL-6 positive CAD patients were studied.

METHODS

During the period from March 2005 to June 2007, 192 CAD patients and controls attending the cardiology clinic of Safdarjung Hospital, New Delhi, India were enrolled. ELISA was performed for the estimation of Cp IgA, high sensitive C-reactive protein (hsCRP), and cytokines IL-6, IL-2, and TNF-alpha in CAD patients and controls.

RESULTS

IL-6 was significantly higher in CAD patents with medium and higher Cp IgA levels (35 vs. 10 and 32 vs. 4) compared to controls. Physiological features and baseline characteristics of CAD were significantly higher in IL-6 positive CAD patients. Additionally, in CAD patients IL-6 was significantly correlated with hsCRP (p<0.001, r=0.42).

CONCLUSIONS

Our results lead us to hypothesize the role of IL-6 in the pathogenesis of CAD, which may subsequently get accelerated through Cp infection.

The association between peptidoglycan recognition protein-1 and coronary and peripheral atherosclerosis: Observations from the Dallas Heart Study

BACKGROUND

Peptidoglycan recognition protein-1 (PGLYRP-1) is part of the innate immune system and binds to peptidoglycan, a component of bacterial cell walls that has been found in human atherosclerotic lesions. Chronic exposure to bacterial antigens may cause or exacerbate the inflammatory response to lipid deposition within arterial walls. We hypothesized that PGLYRP-1 is associated with subclinical atherosclerosis as measured by computed tomography and magnetic resonance imaging.

METHODS AND RESULTS

PGLYRP-1 was measured in 3222 subjects in the Dallas Heart Study, a probability-based population sample age 30-65 including 50% African-Americans and 56% women. Coronary artery calcium (CAC) was measured by electron beam computed tomography (n=2467), abdominal aortic wall thickness (AWT) by magnetic resonance imaging (MRI) (n=2270), and abdominal aortic plaque burden (APB) by MRI (n=2256). In univariable analyses, increasing levels of PGLYRP-1 were associated with all major cardiovascular risk factors, with inflammatory markers such as C-reactive protein, and with CAC, AWT, and APB (p<0.0001 for each). In multivariable models adjusted for traditional risk factors, logPGLYRP-1 remained significantly associated with CAC (OR 1.1, 95% CI 1.01-1.3 per S.D.; p=0.04) and AWT (p=0.009) but not APB (p=0.09). Further adjustment for novel biomarkers associated with PGLYRP-1 and atherosclerosis attenuated the association with CAC (p=0.18) but not with AWT (p=0.01) or APB (p=0.037).

CONCLUSION

In this first reported clinical study of PGLYRP-1 in humans, PGLYRP-1 levels were independently associated with atherosclerosis phenotypes that represent different vascular beds and stages of atherosclerosis.

Immunoproteomic identification and serological responses to novel Chlamydia pneumoniae antigens that are associated with persistent C. pneumoniae infections

The controversial discussion about the role of Chlamydia pneumoniae in atherosclerosis cannot be solved without a reliable diagnosis that allows discrimination between past and persistent infections. Using a proteomic approach and immunoblotting with human sera, we identified 31 major C. pneumoniae Ags originating from 27 different C. pneumoniae proteins. More than half of the proteins represent Chlamydia Ags not described previously. Using a comparative analysis of spot reactivity Pmp6, OMP2, GroEL, DnaK, RpoA, EF-Tu, as well as CpB0704 and CpB0837, were found to be immunodominant. The comparison of Ab-response patterns of sera from subjects with and without evidence for persisting C. pneumoniae, determined by multiple PCR analysis of PBMC and vasculatory samples, resulted in differential reactivity for 12 proteins, which is not reflected by reactivity of the sera in the microimmunofluorescence test, the current gold standard for serodiagnosis. Although reactivity of sera from PCR-positive donors was increased toward RpoA, MOMP, YscC, Pmp10, PorB, Pmp21, GroEL, and Cpaf, the reactivity toward YscL, Rho, LCrE, and CpB0837 was decreased, reflecting the altered protein expression of persisting C. pneumoniae in vitro. Our data provide the first evidence of a unique Ab-response pattern associated with persistent C. pneumoniae infections, which is a prerequisite for the serological determination of persistently infected patients.

Multiple Chlamydiaceae species in trachoma: implications for disease pathogenesis and control

BACKGROUND

Chlamydia trachomatis is a unique obligate intracellular bacterium that remains the leading cause of sexually transmitted bacterial diseases and preventable blindness worldwide. Chronic ocular infections are referred to as trachoma, and predominate in developing countries. Since 2001, the World Health Organization has promoted control strategies including antibiotics, improved hygiene, and environmental measures with limited success. Consequently, a vaccine is urgently needed. Integral to vaccine design is an understanding of the interactions of the pathogen and host immune response. Various animal models of trachoma show that urogenital C. trachomatis strains and other species of the family Chlamydiaceae produce severe conjunctival inflammation and scarring similar to that of the ocular C. trachomatis strains. However, we do not know the extent of organisms that may be involved in human trachoma. Furthermore, C. trachomatis heat shock protein 60 (Hsp60) has been implicated in inflammation and conjunctival scarring but the role of other Chlamydiaceae Hsp60 in disease pathogenesis has not been examined. In this study, we set out to identify whether other Chlamydiaceae species are present in trachoma, and determine their association with severity of clinical disease and with mucosal and systemic immune responses to Chlamydiaceae species-specific Hsp60 to further investigate the immunopathogenesis of this blinding disease.

METHODS AND FINDINGS

We randomly selected nine of 49 households in a trachoma-endemic region of Nepal. Trachoma was graded, and real-time, quantitative (k)PCR was used to detect genomic DNA and cDNA (from RNA) for Chlamydiaceae ompA and 16S rRNA genes, respectively, from conjunctival swabs. IgG antibody responses to recombinant (r) Chlamydiaceae species-specific Hsp60 were determined for tears and sera. Surprisingly, all three species-C. trachomatis, Chlamydophila psittaci, and Chlamydophila pneumoniae-were detected in eight (89%) study households; one household had no members infected with C. pneumoniae. Of 80 (63%; n = 127) infected individuals, 28 (35%) had infection with C. psittaci, or C. pneumoniae, or both; single and dual infections with C. psittaci and C. pneumoniae were significantly associated with severe conjunctival inflammation (OR 4.25 [95% confidence interval (CI), 2.9-11.3], p = 0.009] as were single infections with C. trachomatis (OR 5.7 [95% CI, 3.8-10.1], p = 0.002). Of the 80 infected individuals, 75 (93.8%) were also positive for 16S rRNA by kPCR for the same organism identified by ompA. Individuals with tear IgG immunoreactivity to Chlamydiaceae rHsp60 were eight times more likely than individuals without tear immunoreactivity to be infected (95% CI 6.4-15.1; p = 0.003), 6.2 times more likely to have severe inflammation (95% CI 4.4-12.6; p = 0.001), and 5.7 times more likely to have scarring (95% CI 3.9-11.1; p = 0.019) while individuals with serum IgG immunoreactivity were 4.1 times more likely to be infected (95% CI 3.1-10.1; p = 0.014).

CONCLUSIONS

We provide substantial evidence for the involvement of C. psittaci and C. pneumoniae, in addition to C. trachomatis, in trachoma. The distribution of Chlamydiaceae species by household and age suggests that these infections are widespread and not just sporadic occurrences. Infection with multiple species may explain the failure to detect chlamydiae among active trachoma cases, when only C. trachomatis is assayed for, and the failure of clinically active cases to resolve their disease following what would be considered effective C. trachomatis treatment. The evidence for viable (RNA-positive) organisms of all three species in single and coinfections, the significant association of these infections with severe inflammation, and the significant association of tear and serum IgG responses to Chlamydiaceae Hsp60 with inflammation and scarring, support the role of all three species in disease pathogenesis. Thus, while our findings should be confirmed in other trachoma-endemic countries, our data suggest that a reevaluation of treatment regimens and vaccine design may be required. Understanding the full impact of Chlamydiaceae species on the epidemiology, immunopathology, and disease outcome of trachoma presents a new challenge for Chlamydiaceae research.

Chlamydia pneumoniae aggravates vein graft intimal hyperplasia in a rat model

Background

Along with angioplasty, autologus vein grafts are commonly used for artery bypass grafting in patients with advanced arterial stenosis and drug-resistant angina pectoris. Although initially a successful procedure, long-term functionality is limited due to proliferation and migration of smooth muscle cells. Like in atherosclerosis, common chronic infections caused by viruses and bacteria may contribute to this process of vein graft failure. Here we investigated the possible role of Chlamydia pneumoniae (Cpn) in the pathogenesis of venous graft failure in an experimental animal model. In 2 groups (n = 10 rats/group), an epigastric vein-to-common femoral artery interposition graft was placed. Immediately thereafter, rats were infected with Cpn (5*10⁸ IFU) or injected with control solutions. Rats were sacrificed three weeks after surgery and the grafts were harvested for morphometrical and immunohistochemical analysis.

Results

Cpn administration immediately after vein grafting resulted in a significant increase in medial cross-sectional area, wall thickness and total wall area. There were no significant differences in T-cell or macrophage influx. Likewise, although positive immunostaining for both HSP60 and CRP could be detected, no differences were found between groups. Based on the observation that the number of cells/μm² was also not altered, we conclude that Cpn infection stimulates smooth muscle cell proliferation by hereunto unknown molecular mechanisms, resulting in a significant increase in intimal hyperplasia.

Conclusion

In conclusion, in a well defined animal model we present here for the first time evidence for a role of Chlamydia pneumoniae in the process of venous graft failure.

Endothelial cells are protected against phagocyte-transmitted Chlamydophila pneumoniae infections by laminar shear stress Gueinzius: Shear stress protects from C. pneumoniae infection

The respiratory pathogen Chlamydophila pneumoniae can be detected in atherosclerotic vessels, but the mechanism of dissemination from lung to vasculature remains unknown. Disturbance of vascular shear stress is a risk factor for atherosclerosis. We investigated whether polymorphonuclear neutrophils (PMN) might serve as carriers, transmitting C. pneumoniae to endothelial cells and how this is affected by shear stress. PMN were prepared from blood and incubated with C. pneumoniae. Real-time PCR and Pathfinder staining showed that after 1h, 20% of C. pneumoniae were ingested and started to form inclusions. When infected PMN were co-incubated with HUVEC for 96h, 10% of PMN-ingested C. pneumoniae were transmitted to HUVEC as shown by PCR and confocal microscopy. Infection of HEp-2 cells with C. pneumoniae harvested from HUVEC resulted in C. pneumoniae replication and confirmed that the bacteria remained infective. Exposure to laminar shear stress in a rotating cone-and-plate apparatus did not affect the transmission of C. pneumoniae from PMN to HUVEC, but led to a 75% reduction of inclusion formation. This can explain the focal distribution of C. pneumoniae in the vasculature and links two risk factors of atherosclerosis, i.e. the lack of laminar flow and infection.

Measurement of Chlamydia pneumoniae bacterial load in peripheral blood mononuclear cells may be helpful to assess the state of chlamydial infection in patients with carotid atherosclerotic disease

BACKGROUND

Chlamydia pneumoniae has been repeatedly associated with atherosclerotic cardiovascular diseases. We investigated the pattern of distribution of C. pneumoniae among patients with carotid atherosclerotic disease evaluating chlamydial load in carotid plaque, peripheral blood mononuclear cells (PBMC) and lymph node from same patient.

METHODS AND RESULTS

Thirty carotid plaques, 30 PBMC and 30 lymph nodes were examined by real-time PCR assay. C. pneumoniae DNA was detected, in carotid plaques, PBMC and lymph nodes in 11 patients; in carotid plaques and PBMC in five patients; in PBMC and lymph nodes in four patients; in lymph nodes in two patients; and in PBMC only in one patient. C. pneumoniae DNA in PBMC significantly coincided with the presence of the respective DNA in carotid plaque (p=0.0001) and lymph node (p=0.02). A higher chlamydial load was detected in PBMC than in lymph nodes and carotid plaques. More than 90% of patients with carotid plaques, PBMC and lymph nodes positive to C. pneumoniae were symptomatic, smokers, hypertensives, dyslipidemics and showed carotid plaques with rupture on the surface, hemorrhage and thrombosis.

CONCLUSION

The measurement of chlamydial load in PBMC may be helpful in the future to assess the state of C. pneumoniae infection and the risk of developing sequelae.

C-reactive protein, stroke, and statins

C-reactive protein (CRP) is an important indicator and player in inflammatory diseases such as stroke. It may be involved in the earliest stages of stroke. Monitoring the levels of CRP may help in the prevention and treatment of stroke. Statin drugs may be useful in lowering CRP levels and the incidence of stroke.

Carotid endarterectomy for asymptomatic plaque

Statistical correlations are linear noninteractive relationships, but the dynamics of causation are nonlinear and involve complex interactions where variables change through their effect on one another and interact with the context of the patient over time. The discovery and interpretation of plaque vulnerable features in the individual patient are not determined for the asymptomatic patient being considered for carotid endarterectomy. New technologies for identification of plaque chemical and morphologic composition are on the horizon and may be applicable to certain patients but change in their usefulness as the plaque and patient change over time.