Alterations in cardiac function and gene expression during autoimmune myocarditis in mice

Area of Science:

• Cardiovascular Science
• Immunology
• Pathology

Background:

• Myocarditis is linked to heart failure pathogenesis.
• The precise relationship between myocardial inflammation, cardiac dysfunction, and gene expression changes remains unclear.

Purpose of the Study:

• To investigate if autoimmune-induced myocardial inflammation and fibrosis progress to cardiac dysfunction.
• To determine if this progression leads to a heart failure phenotype.

Main Methods:

• SWXJ mice were immunized with cardiac myosin to induce autoimmune myocarditis.
• Cardiac function was assessed using cardiac catheterization.
• Heart tissues were analyzed for inflammation, fibrosis, and myocyte gene expression via histology and Northern blot.

Main Results:

• Mice with myocarditis showed increased heart weight/body weight ratio from day 14.
• Cardiac function declined from day 21, accompanied by significant fibrosis.
• Gene expression analysis revealed increased atrial naturietic factor and decreased myosin heavy chain alpha starting day 21.

Conclusions:

• Autoimmune heart inflammation causes significant cardiac dysfunction.
• The observed dysfunction and phenotypic alterations resemble human and animal models of heart failure.
• This study establishes a link between autoimmune myocarditis and the development of heart failure.