Chlamydia pneumoniae infection is associated with coronary artery disease but not implicated in inducing plaque instability

Chlamydia trachomatis and Chlamydia pneumoniae Interaction with the Host: Latest Advances and Future Prospective

Research in Chlamydia trachomatis and Chlamydia pneumoniae has gained new traction due to recent advances in molecular biology, namely the widespread use of the metagenomic analysis and the development of a stable genomic transformation system, resulting in a better understanding of Chlamydia pathogenesis. C. trachomatis, the leading cause of bacterial sexually transmitted diseases, is responsible of cervicitis and urethritis, and C. pneumoniae, a widespread respiratory pathogen, has long been associated with several chronic inflammatory diseases with great impact on public health. The present review summarizes the current evidence regarding the complex interplay between C. trachomatis and host defense factors in the genital micro-environment as well as the key findings in chronic inflammatory diseases associated to C. pneumoniae.

Chlamydia Pneumoniae Infection in Patients with Acute Coronary Syndrome: A Clinical and Serological 1-Year Follow-Up

The role of Chlamydia pneumoniae infection in pathogenesis and prognostic stratification of patients with acute coronary syndromes is still unclear. However, a limitation of many studies is the evaluation of the long-term prognostic role of a sample obtained during the acute phase, whereas the assessment of the temporal trend of antibody titers could be more useful. One-hundred and fourteen consecutive patients with acute coronary syndromes (71 with acute myocardial infarction and 43 with unstable angina) were studied. Blood samples were obtained immediately after hospital admission and 1, 3, 6 and 12 months after the acute event. The microimmunofluorescence test was used to detect C. pneumoniae specific antibodies. The incidence of new coronary events (death, myocardial infarction, recurrent angina) was recorded during the 1-year follow-up period. No significant difference was found between patients with (n = 35) or without (n = 79) new coronary events (N.C.E.) regarding baseline and serial values of C. pneumoniae antibodies. The rate of high titers at any time of follow-up was also similar in the two groups: IgG ≥1:512 were present in 52%, 64%, 55% and 32% of N.C.E.+ patients, and in 48%, 54%, 52% and 36% of N.C.E.- patients at 1, 3, 6 and 12 months respectively; IgA ≥ 1:256 were present in 26%, 23%, 30% and 23% of N.C.E.+ patients and in 20%, 30%, 25% and 19% of N.C.E.- patients at 1, 3, 6 and 12 months respectively. Our data indicate that elevated titers of C. pneumoniae antibodies, even with a serial 1-year evaluation, are not a predictor of future coronary events in patients with acute myocardial infarction or unstable angina.

Differential identification of atypical pneumonia pathogens in aorta and internal mammary artery related to ankle brachial index and walking distance

BACKGROUND

We studied the existence of agents in aorta biopsies, such as Chlamydia pneumoniae, cytomegalovirus, and Mycoplasma pneumoniae, that are thought to have a role in atherosclerosis etiopathogenesis role, and their association with peripheral artery disease.

MATERIALS AND METHODS

We examined aorta wall and internal mammarian artery (IMA) biopsies taken from two different places in 63 patients in whom coronary artery bypass was performed. In these biopsies, we evaluated the deoxyribonuclease (DNA) of these microorganisms using polymerase chain reaction. From the same patients, we recorded the ankle brachial index, road walking distance information, lipid profile, C-reactive proteins, blood parameters such as fibrinogen, and the patient's operation data.

RESULTS

In the nine aorta biopsies taken from 63 patients, we isolated C pneumoniae DNA. In IMA biopsies taken from the same patients, we detected no microorganism DNA (P < 0.001). In the same aorta biopsies, we found no cytomegalovirus or M pneumoniae DNA. We examined 12 patients using an index value of 0.9 in the ankle brachial index evaluation; eight had C pneumoniae in the aorta biopsies (P < 0.001).

CONCLUSIONS

We found a significant relationship between C pneumoniae DNA and the existence of peripheral artery disease. In the development of atherosclerosis with C pneumoniae, there may be a determinant pathogen in both the aorta and the peripheral arteries. The nonexistence of C pneumoniae DNA in the IMA biopsies may indicate infectious agents because of the predominant endothelial functions in this artery, and thus its resistance to atherosclerosis.

The Elusive but Pathogenic Peptidoglycan of Chlamydiae

Chlamydia species cause a broad spectrum of diseases in humans including severe chronic sequelae related to persistent forms. Despite the lack of detectable amounts of peptidoglycan, several studies suggest the presence of small quantities of peptidoglycan or its derivative at least in some stages of the growth cycle. Based on recent discovery in Chlamydiae of the aminotransferase pathway for biosynthesis of meso-diaminopimelic acid, we demonstrated the up-regulation of the gene (cp0259) encoding L,L-diaminopimelate aminotransferase in chlamydial persistent forms. This finding may be important in the search for target molecules to diagnose and treat Chlamydia-associated chronic diseases.

Inflammatory responses associated with acute coronary syndrome up-regulate IRAK-M and induce endotoxin tolerance in circulating monocytes

Acute coronary syndrome (ACS) groups different cardiac diseases whose development is associated with inflammation. Here we have analyzed the levels of inflammatory cytokines and of members of the TLR/IRAK pathway including IRAK-M in monocytes from ACS patients classified as either UA (unstable angina), STEMI (ST-elevation myocardial infarction) or NSTEMI (non-ST-elevation myocardial infarction). Circulating monocytes from all patients, but not from healthy individuals, showed high levels of pro-inflammatory cytokines, TNF-alpha and IL-6, as well as of IRAK-M and IL-10. TLR4 was also up-regulated, but IRAK-1, IRAK-4 and MyD88 levels were similar in patients and controls. Further, we investigated the consequences of cytokines/IRAK-M expression on the innate immune response to endotoxin. Ex vivo responses to LPS were markedly attenuated in patient monocytes compared to controls. Control monocytes cultured for 6 h in supplemented medium (10% serum from ACS patients) expressed IRAK-M, and LPS stimulation failed to induce TNF-alpha and IL-6 in these cultures. Pre-incubation of the serum with a blocking anti-TNF-alpha antibody reduced this endotoxin tolerance effect, suggesting that TNF-alpha controls this phenomenon, at least partially. We show for the first time that inflammatory responses associated with ACS induce an unresponsiveness state to endotoxin challenge in circulating monocytes, which correlates with expression of IRAK-M, TLR4 and IL-10. The magnitude of this response varies according to the clinical condition (UA, STEMI or NSTEMI), and is regulated by TNF-alpha.

Interaction between Chlamydia pneumoniae seropositivity, inflammation and risk factors for atherosclerosis in patients with severe coronary stenosis

OBJECTIVE

To investigate whether Chlamydia pneumoniae (Cpn) seropositivity in patients with suspected coronary artery disease (CAD) (n = 81) is associated with increases in markers of inflammation, the severity of coronary atherosclerosis, and traditional risk factors for cardiovascular events.

MATERIAL AND METHODS

The severity of coronary atherosclerosis was ranked by Gensini score. Inflammation and endothelial dysfunction were evaluated using white blood cell counts and levels of high-sensitivity C-reactive protein (hs-CRP), ferritin, tumour necrosis factor-alpha (TNF-alpha), interleukins 1beta and 6 (IL-1beta, IL-6), soluble intercellular adhesion molecule-1 (sICAM-1), E-selectin and oxidized LDL (oxLDL), and these were compared between Cpn-seropositive and seronegative individuals.

RESULTS

IgA and IgG Cpn seropositivity were significantly associated with the presence of CAD (p = 0.005) and were independent predictive factors for the severity of coronary atherosclerosis (p = 0.005). Elevated levels of IL-6 (p = 0.027) and triglyceride (p = 0.038) and low levels of high-density lipoprotein cholesterol (HDL-C) (p = 0.038) were significantly predicted by Cpn IgA and IgG seropositivity.

CONCLUSIONS

Seropositivity for Cpn is a risk factor for patients with significant angiographically documented coronary stenosis. Additionally, Cpn seropositivity was significantly associated with dyslipidemia and elevated IL-6, known risk factors for CAD. These observations indicate that Cpn infection may be one entry point to the causal or contributory pathways that lead to atherosclerosis and its clinical manifestations.

Chlamydia pneumoniae and coronary artery disease: controversial results of serological studies

I have read with great interest the article published by Carratelli et al. Briefly they have reported increased levels of inflammatory markers and elevated titers of IgG and IgA of C. pneumoniae by using both ELISA and MIF method. There are several factors which may underly the controversial results of seroepidemiological studies. I have commented on the report of Carratelli et al. regarding some of these factors.

Seropositivity to Chlamydia pneumoniae or Helicobacter pylori and coronary artery disease

Our aim was to investigate the relationship between the serologic status concerning Chlamydia pneumoniae and Helicobacter pylori with the presence of coronary artery disease (CAD), which remain a controversial issue in literature. We studied 208 patients with CAD and 94 controls with no evidence of obstructive CAD; all of them angiographically confirmed. The seropositivity to C. pneumoniae was 91% in patients with CAD vs 86% in controls (P>0.05). The H. pylori seroprevalence rates were 77% and 68%, respectively (P>0.05). The multivariate analysis, adjusting for age, sex, educational level, diabetes, hypertension, obesity, smoking, family history of CAD and lipids, confirmed the results of univariate analysis. Therefore, this study adds evidence against the association of seropositivity to C. pneumoniae and H. pylori with angiographically documented CAD.