MadSci Network: Medicine
Query:

Re: Does the bacterium clamydia pneumoniae contribute to heart attacks ?

Date: Mon Apr 10 20:24:14 2000
Posted By: M. Salik Jahania, M.D., Suregry, Cardiothoracic, University of Kentucky
Area of science: Medicine
ID: 954961765.Me
Message:

That is a very good question. Considerable data exists to support that hypothesis. I have attached herein several recent papers published in international medical journals that address the questions you ask. Hope this helps!! Previous work has suggested an association between Chlamydia pneumoniae infection and coronary artery disease. There is no direct evidence that infections themselves directly lead to coronary artery disese. Only the incidence of certain infectious organisms concomitantly ccurring in coronary arery disease is higher than in people with no coronary artery disease. Atherosclerosis is the main underlying cause of coronary heart disease, which in turn is the most common cause of death in the industrialized world. An acute event in coronary heart disease is typically precipitated by thrombosis occurring at the site of atherosclerotic plaque disruption. Atherosclerotic plaques consist of a fibrous cap overlying a lipid-rich core. Many cell types are involved in their formation, including platelets, endothelial cells, activated monocytes, macrophages derived from monocytes and smooth muscle cells. The currently accepted hypothesis is that atherosclerosis develops as a response to injury and that it is primarily a chronic inflammatory condition. The endothelium plays an important role in regulating vascular blood flow and it is now apparent that endothelial dysfunction is an important contributor to the pathogenesis of atherosclerosis. There is growing evidence that infection may be a risk factor for atherosclerosis and myocardial infarction. Numerous studies have reported associations between human coronary heart disease (CHD) and bacterial and viral infections. At present, interest is focused on the potential aetiological role of C. pneumoniae which has been repeatedly identified, using various diagnostic techniques, in atherosclerotic lesions. There is also increasing seroepidemiological evidence of the association between C. pneumoniae and CHD. The role of this organism in atherosclerosis may be analogous to that of chronic C. trachomatis infection in trachoma. TITLE: Pathogenesis of atherosclerosis: a possible relation to infection. AUTHORS: Noll G AUTHOR AFFILIATION: Division of Cardiology, University Hospital, Zurich, Switzerland. SOURCE: Atherosclerosis 1998 Oct;140 Suppl 1:S3-9 CITATION IDS: PMID: 9859918 UI: 99075261 Consider this study for example. The underlying mechanism may be associated with damage of the cellular linnig of blood vessels. It is possible to suppose that this infection may be linked to atherosclerosis through an endothelial damage or a systemic endogenous procoagulant and inflammatory activity. TITLE: [Chlamydia pneumoniae infection and cardiac ischemic syndromes] VERNACULAR TITLE: Infezione da Chlamydia pneumoniae e sindromi ischemiche cardiache. AUTHORS: Varveri A; Sgorbini L; Romano S; Aurigemma G; Dagianti A Jr; Sessa R; Di Pietro M; Del Piano M; Dagianti A; Penco M AUTHOR AFFILIATION: Dipartimento di Scienze Cardiovascolari e Respiratorie, Universita degli Studi La Sapienza, Roma. SOURCE: Cardiologia 1998 Oct;43(10):1053-8 The infection was demonstrated by titers of antibodies--enzyme-linked immunosorbent assay or immunofluorescence, and polymerase chain reaction-- and by the findings of C. pneumoniae in the atherosclerotic plaque. To evaluate the association between chronic infection with C. pneumoniae, as measured by a high titer of IgG antibody, and CAD a study was designed to explore the relationship between seropositivity to C. pneumoniae and serious coronary events, and to assess whether or not there may be an additional association between established cardiovascular factors and infection with this organism. The serum of 130 patients with proven CAD was tested for the presence of IgG antibodies to C. pneumoniae using an ELISA test. A titer < or = 1:64 using the microinfluorescence method, the recognized "gold standard," correlates with a positive result when using the ELISA method. The patients, 82% male and 18% female, had either myocardial infarction (n = 109) or unstable angina (n = 21) 6 months before the investigation (range 3-24 months). In the CAD group 75% of patients were positive for C. pneumoniae compared to 33% in the control group (P = 0.001). No increased correlation could be demonstrated between traditional risk factors and C. pneumoniae infection, except in those patients with diabetes mellitus. These findings suggest that chronic C. pneumoniae infection may be a significant risk factor for the development of CAD, but this correlation should be investigated further Two chronic infections, HSV-1 and Cpn, increase the risk of coronary heart disease. The effect is emphasized in subjects with ongoing inflammation, denoted by increased CRP levels. ON the other hand people habe found conflicting evidence. although C. pneumoniae was associated with several risk factors for cardiovascular disease in a large cross-sectional population, annother study found no independent association between seroprevalence to C. pneumoniae and carotid atherosclerosis as measured by carotid IMT.Consider this study for this example. TITLE: Lack of association between seropositivity to Chlamydia pneumoniae and carotid atherosclerosis. AUTHORS: Coles KA; Plant AJ; Riley TV; Smith DW; McQuillan BM; Thompson PL AUTHOR AFFILIATION: Department of Public Health, The University of Western Australia, Nedlands. katie@dph.uwa.edu.au SOURCE: Am J Cardiol 1999 Oct 1;84(7):825-8 CITATION IDS: PMID: 10513782 UI: 99441940 Refer you to this study wchihc is a good review of this question TITLE: The possible role of infections in acute myocardial infarction. AUTHORS: Meier CR AUTHOR AFFILIATION: Basel Pharmacoepidemiology Unit, Department of Internal Medicine, University Hospital, Switzerland. SOURCE: Biomed Pharmacother 1999 Oct;53(9):397-404 Other references TITLE: Can infections cause heart attacks? SOURCE: Johns Hopkins Med Lett Health After 50 1999 Sep;11(7):6 CITATION IDS: PMID: 10472205 UI: 99401425 MAIN MESH HEADINGS: Chlamydia Infections/*complications Myocardial Infarction/*microbiology TITLE: Antibiotics--a treatment for heart disease? [news] SOURCE: Mayo Clin Health Lett 1999 Jul;17(7):4 CITATION IDS: PMID: 10424195 UI: 99352994 MAIN MESH HEADINGS: Antibiotics/*therapeutic use TITLE: Chlamydia pneumoniae infection and atherosclerotic coronary disease. AUTHORS: Sessa R; Di Pietro M; Santino I; del Piano M; Varveri A; Dagianti A; Penco M AUTHOR AFFILIATION: Department of Clinical Microbiology, "La Sapienza" University, Rome, Italy. SOURCE: Am Heart J 1999 Jun;137(6):1116-9 CITATION IDS: PMID: 10347340 UI: 99277975 ABSTRACT: BACKGROUND: Previous works have suggested an association between Chlamydia pneumoniae infection and coronary heart disease. We evaluated the prevalence of C. pneumoniae infection in patients with acute myocardial infarction (AMI) and coronary heart disease (CHD). METHODS AND RESULTS: Ninety-eight patients with AMI, 80 patients with CHD, and 50 control subjects matched for age and sex were investigated. Immunoglobulin (Ig)M, IgG, and IgA antibodies to C pneumoniae were measured by the microimmunofluorescence test. IgM antibodies were not found; IgG positivity was found in 58.2% of the AMI group, 60.0% of the CHD group, and 38% of the control group, whereas for IgA, positivity was found in 33.7%, 43.7%, and 22% of cases in AMI, CHD, and control groups, respectively. Titers indicating reinfection were found in AMI and CHD groups in 6.1% and 10%, respectively, whereas titers indicating chronic infection were found in 14% of the AMI group and 25% of the CHD group. A significant correlation was found between chronic C pneumoniae infection and dyslipidemias in the AMI and CHD groups (P =.003; P =. 0006). CONCLUSIONS: The results suggest that chronic C pneumoniae infection may be associated with the development of atherosclerotic coronary disease. In our next step, we will test whether antichlamydial antibiotics may help to reduce the risk of atherosclerotic disease.


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