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Chronic infection and coronary artery disease
1Division of Cardiology, LDS Hospital, University of Utah, Salt Lake City, USA. ldbmuhle@ihc.com
Insights
Chronic infections are linked to atherosclerosis, but direct causes remain unproven. Research explores how infections like Chlamydia pneumoniae may initiate or worsen cardiovascular disease.
Area of Science:
- Cardiovascular Science
- Infectious Disease Epidemiology
Background:
- Chronic infections are increasingly associated with atherosclerosis and its complications, including heart attack and stroke.
- Current evidence largely shows associations, lacking definitive causative links comparable to H. pylori and peptic ulcer disease.
Purpose of the Study:
- To explore potential mechanisms by which chronic infections contribute to atherogenesis.
- To identify infectious agents with the strongest evidence for a causative role in atherosclerosis.
Main Methods:
- Review of existing literature on chronic infections and atherosclerosis.
- Analysis of proposed pathophysiological pathways, including direct colonization and immune-mediated effects.
Main Results:
- Chlamydia pneumoniae and cytomegalovirus are key agents implicated in atherosclerosis.
- Other potential contributors include H. pylori, periodontal pathogens, and hepatitis A.
- Mechanisms involve direct vessel damage, enhanced inflammation, and plaque destabilization.
Conclusions:
- Chronic infections may play a role in the initiation, progression, or destabilization of atherosclerotic plaques.
- Further research is needed to confirm causative relationships and explore antibiotic treatments.
Abstract:
On a variety of fronts, chronic infection has been found to be significantly associated with the development of atherosclerosis and the clinical complications of unstable angina, myocardial infarction, and stroke. For the most part, these are still just associations. Specific causative relationships on par with that determined between H. pylori and peptic ulcer disease have not yet been established. Potential mechanisms whereby chronic infections may play a role in atherogenesis are myriad. In the case of C. pneumoniae, the effect may result from direct vessel wall colonization, which may damage the vessel directly or indirectly by initiating immunologic responses. In other cases, the effect may simply be that of enhancing the preexisting chronic inflammatory response of the body to standard risk factors, such as hyperlipidemia. Even though the infectious agent may not directly infect the vessel wall, it may perform its critical role from afar. Chronic infection might also influence preexisting plaque by enhancing T cell activation or other inflammatory responses that may participate in the destabilization of the intimal cap. Chronic infection may play a role in the initiation, progression, or destabilization of atherosclerotic plaques. The infectious agents with the most evidence to support a causative role in atherosclerosis include C. pneumoniae and cytomegalovirus. Evidence is mounting for a variety of other potential agents, including H. pylori, various periodontal agents, and even hepatitis A. Future studies are expected to elucidate further the pathophysiologic relationship between chronic infection and atherosclerosis and to evaluate the potential of a variety of treatment approaches, including antibiotics.