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[Virus and dilated cardiomyopathies]
J B Bouhour1, J M Langlard, H Kopecka
1Clinique cardiologique et des maladies vasculaires, CHU Nantes, hôpital G. et R. Laennec.
Insights
Dilated cardiomyopathy may stem from viral infections, particularly enteroviruses, potentially leading to chronic disease. Genetic and immune factors can influence this progression, highlighting a complex interplay in heart muscle conditions.
Area of Science:
- Cardiology
- Virology
- Immunology
Context:
- Dilated cardiomyopathy (DCM) is diagnosed when no clear cause for ventricular dilatation and hypokinesia is found.
- Emerging research suggests genetic, immunological, and infectious factors, often in combination, contribute to DCM development.
- The transition from subclinical viral myocarditis to chronic DCM is a key area of investigation.
Purpose:
- To explore the role of viral infections, specifically enteroviruses, in the pathogenesis of dilated cardiomyopathy.
- To investigate the association between genetic predisposition, immune deficiencies, and the development of autoimmune myocarditis.
- To examine the epidemiological evidence linking enteroviruses to DCM and analyze molecular findings in affected myocardium.
Summary:
- Experimental models demonstrate a link between viral myocarditis and DCM, with genetic and immune factors acting as cofactors for autoimmune myocarditis.
- Clinical studies show elevated neutralising anti-coxsackie B virus antibodies in DCM patients compared to controls.
- The presence of enterovirus genome sequences in myocardial tissue, detected via molecular hybridization and PCR, suggests a potential mechanism for progressive myocyte destruction, though results are currently discordant.
Impact:
- This research underscores the potential etiological role of viral infections in dilated cardiomyopathy, guiding future diagnostic and therapeutic strategies.
- Understanding the interplay of viral, genetic, and immune factors is crucial for unraveling the complex mechanisms of DCM.
- Further research is needed to reconcile discordant findings and solidify the role of enteroviruses in DCM pathogenesis.
Abstract:
Dilated cardiomyopathy is so called when an etiological investigation is negative and no cause can be found for ventricular dilatation-hypokinesia. Current research points to genetic, immunological and infectious factors, often associated, and the passage of subclinical viral myocarditis to chronic disease. There is a lot of evidence in favour of this hypothesis. In the experimental model, the relationship between viral myocarditis and dilated cardiomyopathy has been demonstrated with, as cofactors, a genetic predisposition and an immunitary deficiency leading to an auto-immune subacute myocarditis. In the clinical setting, the enterovirus with a high cardiac tropism seems to play an epidemiological role in the genesis of dilated cardiomyopathy. The concentrations of neutralising anti-coxsackie B virus antibodies is higher in subjects with dilated cardiomyopathy than in a control population. The frequency of lymphocytic infiltration, a marker of dysimmunitary myocarditis, is variable from study to study but the presence of sequences of enterovirus genome in the myocardium could explain slow replication of the virus progressively destroying the myocytes. Techniques of molecular hybridization with or without prior genic amplification by the "Polymerase Chain Reaction" have demonstrated such sequences of specific enterovirus genome but discordant results require further studies.