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Infections and atherosclerosis
1Department in Oulu, KTL, National Public Health Institute, Finland. maija.leinonen@ktl.fi
Insights
Infectious agents like Chlamydia pneumoniae may contribute to coronary heart disease (CHD). Research is ongoing to confirm if antibiotics could treat this inflammatory condition.
Area of Science:
- Cardiovascular Science
- Infectious Disease Epidemiology
Background:
- Inflammation and infection were historically linked to atherosclerosis but this theory was largely abandoned.
- Recent research revives the hypothesis that infectious agents may play a role in coronary heart disease (CHD).
Purpose of the Study:
- To review the evidence linking infectious pathogens to atherosclerosis and CHD.
- To explore the potential pathogenetic role of Chlamydia pneumoniae in CHD.
Main Methods:
- Review of seroepidemiological studies associating pathogens with CHD.
- Examination of evidence for pathogen presence in atherosclerotic lesions.
- Consideration of animal studies and preliminary antibiotic intervention trials.
Main Results:
- Herpes viruses (CMV, HSV1), Helicobacter pylori, and Chlamydia pneumoniae are implicated in atherosclerosis.
- The strongest evidence links the respiratory bacterium Chlamydia pneumoniae to CHD.
- Preliminary studies suggest a potential pathogenetic role for C. pneumoniae.
Conclusions:
- While a causal relationship is not yet proven, C. pneumoniae is a strong candidate for contributing to CHD.
- Ongoing research and intervention trials may establish antimicrobial therapy for CHD treatment.
Abstract:
More than a century ago, inflammation and infection were considered to have atherogenic effects. During last century, however, this hypothesis was completely abandoned, and the old idea that coronary heart disease (CHD) possibly has an infectious etiology has only re-emerged in recent years. Both viral and bacterial pathogens have been proposed to be associated with the inflammatory changes found in atherosclerosis. Herpes group viruses, especially cytomegalovirus (CMV) and herpes simplex virus type 1 (HSV1), have been associated with both atherosclerosis and restenosis. Helicobacter pylori and dental infections have also been linked to CHD, but the evidence is strongest for a respiratory tract bacterium, Chlamydia pneumoniae. The association was originally found in seroepidemiological studies, but the presence of organisms in atherosclerotic lesions, the first animal studies and preliminary successful intervention trials with antibiotics suggest that C. pneumoniae may have a pathogenetic role in the disease. The causal relationship has not yet been proven, but ongoing large intervention trials and research on pathogenetic mechanisms may lead to the use of antimicrobial agents in the treatment of CHD in the future.