Background: Transgenic mice expressing the dominant interfering p193 protein in cardiomyocytes (MHC-1152stop mice) exhibit an induction of cell cycle activity and altered remodelling after experimental myocardial infarction (MI).
Objective: To determine whether the altered remodelling results in improved cardiac function in the MHC-1152stop mice after MI, as compared with non-transgenic mice.
Methods: MHC-1152stop mice and non-transgenic littermates were subjected to experimental MI via permanent occlusion of the coronary artery. Infarct size was determined at 24 h and at 4 weeks after MI, and left ventricular pressure–volume measurements were performed at 4 weeks after MI in infarcted and sham-operated animals.
Results: Infarct size in MHC-1152stop mice and non-transgenic littermates was not statistically different at 24 h after MI, as measured by tetrazolium staining. Morphometric analysis showed that infarct scar expansion at 4 weeks after MI was reduced by 10% in the MHC-1152stop mice (p<0.05). No differences in cardiac function were detected between sham-operated MHC-1152stop mice and their non-transgenic littermates. However, at 4 weeks after MI, the ventricular isovolumic relaxation time constant (τ) was decreased by 19% (p<0.05), and the slope of the dP/dtmax–EDV relationship was increased 99% (p<0.05), in infarcted MHC-1152stop mice as compared with infarcted non-transgenic littermates.
Conclusion: Expression of the dominant interfering p193 transgene results in a decrease in infarct scar expansion and preservation of myocardial function at 4 weeks after MI. Antagonism of p193 activity may represent an important strategy for the treatment of MI.
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Funding: This work has been supported by the Hein J J Wellens Foundation and the Foundation De Drie Lichten (both in The Netherlands), and by grants from the Heart Lung and Blood Institutes of the National Institutes of Health (USA).
Competing interests: None.