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Potential role of the microvasculature in progression of heart failure
1Toronto General Hospital, University of Toronto, Ontario, Canada.
Insights
Cardiac microvasculature abnormalities are linked to heart failure progression. Targeting these microvascular changes may improve outcomes in patients with heart failure and cardiomyopathy.
Area of Science:
- Cardiovascular Biology
- Heart Failure Pathophysiology
- Microvascular Medicine
Background:
- Cardiac injury triggers myocyte remodeling, contributing to heart failure.
- The microvasculature's role in heart failure progression is under-explored.
- Interactions between microvascular endothelium and myocytes are crucial.
Purpose of the Study:
- To investigate the role of cardiac microvasculature in heart failure.
- To explore the association between microvascular abnormalities and cardiomyopathy.
- To examine the impact of mediators like endothelin and nitric oxide.
Main Methods:
- Review of animal models of heart failure and cardiomyopathy.
- Analysis of molecular mediators (endothelin, nitric oxide) in the myocardium.
- Evaluation of preliminary clinical studies on microvascular ischemia.
Main Results:
- Animal models consistently show microvascular abnormalities in heart failure.
- Reversal of microvascular abnormalities correlates with cardiomyopathy improvement.
- Preliminary clinical data suggest microvascular ischemia has prognostic value.
Conclusions:
- Microvascular abnormalities are integral to heart failure progression.
- Endothelin and nitric oxide are key mediators in cardiac microvasculature.
- Therapeutic strategies targeting the microvasculature may benefit heart failure patients.
Abstract:
After cardiac injury, there are changes in the cardiac myocyte morphology, function, matrix, and molecular gene expression. These all play an important role in remodeling of the injured heart, contributing to the progression toward heart failure. The role of the microvasculature in the progression toward heart failure is less well characterized. However, laboratory studies have established that there are important interactions between the microvascular endothelium and the myocyte. Furthermore, in a multitude of animal models of heart failure and cardiomyopathy, there is always an association with microvascular abnormalities. Reversal of these abnormalities is also associated with improvement in the cardiomyopathy. Major mediators that likely play an important role in the microvasculature include endothelin and nitric oxide. These are elaborated by both endothelium and myocyte compartments of the myocardium. Preliminary clinical studies already demonstrate that microvascular ischemia may have prognostic power in patients with nonischemic dilated cardiomyopathy. Results from these studies showed a reduction in mortality from treatment with amlodipine, suggesting a possible benefit based on changes in the microvasculature.