Joint effects of Chlamydia pneumoniae infection and classic coronary risk factors on risk of acute myocardial infarction

The evidence for a role of bacteria and viruses in cardiovascular disease

Inflammation plays a critical role in atherosclerosis and cardiovascular disease. Bacteria and viruses are major causative agents of inflammation in the body which normally develops as a response to infection. It is a logical extention, therefore, to believe bacterial and viral infections may be involved in a variety of presentations of cardiovascular diseases. The purpose of this review is to describe the data and conclusions to date on the involvement of these infectious agents in the induction of cardiovascular disease. The review also discusses the various specific bacteria and viruses that have been implicated in cardiovascular disease and the mechanisms, if known, that these agents induce cardiovascular disease.

Chlamydia pneumoniae and Mycoplasma pneumoniae as two Emerging Risk Factors in Atherosclerosis: Meta-Analysis Study and Systematic Review

BACKGROUND

Previous studies suggested an association between Chlamydia pneumoniae and Mycoplasma pneumonia with atherosclerosis, separately. Until now, according to inconsistent information, the relationship between C.pneumoniae and M.pneumoniae with atherosclerosis is controversial.

OBJECTIVE

the aim of this study, investigate of the association between C.pneumoniae and M.pneumoniae as two separate risk factors with atherosclerosis by systematic review and meta-analysis study.

METHODS

We searched databases such as Pubmed, SID, Magiran, Google scholar and Iranmedex using the following keywords in English and Persian language as C. pneumoniae , M. pneumoniae and atherosclerosis. Data were analyzed with meta-analysis and a random effect model. Also, in this study Heterogeneity of articles were estimated by using I2 index. Finally, data was analyzed with STAT (version 11.2) Results: Among thirty-eight articles for C. pneumoniae and five articles for M. pneumoniae individually reviewed that included 2980 samples for M. pneumoniae and 23298 samples for C. pneumoniae, result demonstrated that association between M. pneumoniae and C. pneumoniae with atherosclerosis is significant with OR (odd ratio) = 1.58 (95% Confidence Interval (CI): 1.00 to 2.50), OR (odd ratio) = 2.25(95% Confidence Interval (CI): 1.91 to 2.64), respectively.

CONCLUSION

This systematic review study provides strong evidence for the role of persistent bacterial infection such as M. pneumoniae and C. pneumoniae in potential atherosclerosis. Thus, a novel way should be employed for the complete management of bacterial infection.

A systematic review exploring the relationship between infection and sudden unexpected death between 2000 and 2016: A forensic perspective

Death due to infectious diseases is a major health concern worldwide. This is of particular concern in developing countries where poor-socio economic status and a lack of healthcare resources contribute to the high burden of disease. In some cases death due to infection can be acute and aggressive, and death may occur without a diagnosis whilst the person is still alive. These deaths may ultimately lead to a medico-legal autopsy being performed. There are various mechanisms by which sudden death due to infection may occur. In addition, there are many risk factors associated with sudden death due to infection, which differ between infants and older individuals. However, it is unclear which pathogens and risk factors are most frequently associated with sudden death due to infection. Therefore a systematic review of articles and case reports published between 1 January 2000 and 30 June 2016 was undertaken in order to (1) explore the relationship between pathogens and their causative role and (2) identify the relationship between predisposing and/or risk factors associated with sudden death due to infection. Major databases were searched and after critical appraisal 143 articles were identified. It was found that respiratory infections and deaths involving bacterial pathogens were most commonly associated with these deaths. In addition the most common risk factors in infants were exposure to tobacco smoke and co-sleeping. In adults the most common risk factors were co-morbid conditions and illnesses. This information aids in a better understanding of these deaths and highlights the need for more research in this field, particularly in developing countries.

Investigation of Chlamydia pneumoniae infection in Moroccan patients suffering from cardiovascular diseases

Chlamydia pneumoniae is an intracellular bacterium responsible for respiratory diseases and is highly involved in cardiovascular disease development, mainly atherosclerosis. The main objective of our study was to evaluate C. pneumoniae prevalence in Moroccan patients suffering from cardiovascular diseases. A total of 115 patients with cardiovascular diseases were enrolled, and their clinical and behavioral information was recorded. Blood was sampled from all patients as well as the atheroma plaques from 36 patients undergoing surgery. Nested PCR was performed for C. pneumoniae DNA detection in both peripheral blood mononuclear cells (PBMCs) and atheroma plaques. Statistical analysis was performed using EpiInfo software. Data analysis showed cardiovascular disease dominance in men, with a sex ratio M/F of 3.4, a majority of tobacco users (52.2%), and many diabetics (44.3%). A significant difference between genders was shown for tobacco use (p<0.05). Positive cases for PBMCs and atheroma plaques were 61% and 86%, respectively, and a significant difference between PBMCs and atheroma plaque infection was identified (p=0.02). Data analysis also showed that 12% of patients presented only C. pneumoniae infection as a risk factor. Therefore, the high prevalence of C. pneumoniae suggests its involvement in atherosclerosis, and further investigation is recommended for confirmation.

Chlamydophila pneumoniae infection and cardiovascular disease

Atherosclerosis is a multifactorial vascular inflammatory process; however, the inciting cause for inflammation remains unclear. Two decades ago, Chlamydophila pneumoniae (formerly Chlamydia pneumoniae) infection was proposed as a putative etiologic agent. We performed a PubMed search using the keywords Chlamydia and atherosclerosis in a Boolean query to identify published studies on C. pneumoniae and its role in atherogenesis, and to understand research interest in this topic. We found 1,652 published articles on this topic between 1991 and 2011. We analyzed relevant published studies and found various serological, molecular, and animal modeling studies in the early period. Encouraged by positive results from these studies, more than a dozen antibiotic clinical-trials were subsequently conducted, which did not find clinical benefits of anti-Chlamydophila drug therapy. While many researchers believe that the organism is still important, negative clinical trials had a similar impact on overall research interest. With many novel mechanisms identified for atherogenesis, there is a need for newer paradigms in Chlamydophila-atherosclerosis research.

Atherosclerosis, inflammation and Chlamydia pneumoniae

Coronary heart disease is the single most common cause of illness and death in the developed world. Coronary atherosclerosis is by far the most frequent cause of ischemic heart disease, and plaque disruption with superimposed thrombosis is the main cause of the acute coronary syndromes of unstable angina, myocardial infarction, and sudden death. Atherosclerosis is the result of a complex interaction between blood elements, disturbed flow, and vessel wall abnormality, involving several pathological processes: inflammation, with increased endothelial permeability, endothelial activation, and monocyte recruitment; growth, with smooth muscle cell proliferation, migration, and matrix synthesis; degeneration, with lipid accumulation; necrosis, possibly related to the cytotoxic effect of oxidized lipid; calcification/ossification, which may represent an active rather than a dystrophic process; and thrombosis, with platelet recruitment and fibrin formation. In this review we discuss these processes and the possible pathological effects of Chlamydia infection and the ensuing phlogosis.

Inflammation, blood pressure, and stroke: an opportunity to target primary prevention?

Promising findings suggest that systemic inflammation and neuroinflammation are central features in cerebrovascular disease. Inflammatory mechanisms are also important participants in the pathophysiology of hypertension. Markers of inflammation have been shown to be upregulated in different forms of cerebrovascular disease, and to correlate with vascular risk. The inhibitor nuclear factor-kB/nuclear factor-kB system is considered a major intracellular inflammatory pathway, mediating most of the vascular inflammatory responses. Increasing evidence indicates that hypertension, through the vasoactive peptides angiotensin and endothelin-1, promotes and accelerates the atherosclerotic process via inflammatory mechanisms. Proinflammatory properties of angiotensin II have been demonstrated. The identification of useful markers of inflammation, of new therapeutic targets to interfere with these mechanisms, and the evaluation of the efficacy of anti-inflammatory treatments will allow progress in our ability to combat cerebrovascular disease and the complications of hypertension. Whether these targets will be useful in the development of risk prediction strategies or therapies for the treatment of stroke in humans is far from clear.

Prevalence of viable Chlamydia pneumoniae in peripheral blood mononuclear cells of healthy blood donors

BACKGROUND

Demonstration of viable Chlamydia (Chlamydophila) pneumoniae in peripheral blood mononuclear cells (PBMNCs) is essential to understand the involvement of C. pneumoniae in atherosclerosis. Nevertheless, the prevalence of viable C. pneumoniae in the blood of healthy donors has not yet been studied.

STUDY DESIGN AND METHODS

The presence of C. pneumoniae transcript in PBMNCs from blood of healthy human donors was assessed by real-time reverse transcription-polymerase chain reaction (RT-PCR) with primers for C. pneumoniae 16S rRNA, which is more sensitive than genomic-DNA-based analysis, and by the use of staining with fluorescein isothiocyanate-conjugated chlamydia monoclonal antibody (MoAb).

RESULTS

Thirteen of 70 donors (18.5%) showed the presence of bacterial transcript in cultured PBMNCs. The prevalence of bacterial detection and bacterial numbers was significantly increased in PBMNC cultures incubated with cycloheximide. Immunostaining of PBMNCs with antichlamydial MoAb also revealed the presence of bacterial antigen in the PBMNCs judged as positive. Nevertheless, cultivation of C. pneumoniae from all PCR-positive donors was unsuccessful. There was no significant correlation between the presence of chlamydia and either sex or current smoking habits. A possible age variation, however, in the presence of chlamydia in blood of healthy donors was suggested by the results obtained.

CONCLUSION

The bacterial transcripts in PBMNCs obtained from healthy donors were detected by the RT-PCR method. Viable C. pneumoniae may be present in healthy human PBMNCs.