- 1. Acute
2. Chronic
Like chronic inflammation can plague other parts of the body, it can also occur in the heart, causing a form of the disease called chronic myocarditis. As the heart muscle becomes increasingly inflamed, whether because of an ongoing viral infection or an autoimmune condition that targets proteins of the heart. After months or even years of chronic myocarditis, patients can develop a condition called dilated cardiomyopathy (DCM), a condition that usually impacts the left ventricle initially and moves to the atria (American Heart Association). As the chambers of the heart stretch and grow thinner, the heart’s contractions grow abnormal and the heart becomes excessively and dangerously weak.
This condition sometimes requires a heart transplantation for a full recovery. Although other health problems can lead to dilated cardiomyopathy, 30 percent of all clinical cases stem from an original viral infection.
In a Current Pharmaceutical Design review article, Sally A. Huber, PhD, from the University of Vermont Department of Pathology described an experimental animal model to first study the apparent sex bias in both acute and chronic myocarditis. Testosterone in males is thought to promote autoimmunity, increasing the chance that males will have a reaction to heart proteins that could cause myocarditis. On the other hand, the estrogen prominent in females actually suppresses viral infection and autoimmunity, making them less prone to myocarditis.
Huber found from her studies that eosinophils and other leukocytes infiltrate the myocardium during inflammation, but treating this penetration with immunosuppressive treatments is not only ineffective, it is harmful in this situation. Ultimately, clearance of the virus causing myocarditis would solve the condition, and suppressing the immune system would make clearing the virus virtually impossible.
Huber’s goal after writing this review is to find better therapeutic agents for treating viral myocarditis, and the animal model from her review article showed improved cardiac function in a clinical trial using interferon-beta to treat chronic viral infections causing myocarditis.
Source: Bentham Science Publishers