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Submitted on September 25, 2008
Revised on December 5, 2008
Accepted on December 10, 2008
From the Feinberg Cardiovascular Research Institute, Feinberg School of Medicine, Northwestern University, Chicago Ill.
* To whom correspondence should be addressed. E-mail: r-kishore{at}northwestern.edu.
Persistent inflammatory response has adverse effects on left ventricular (LV) function and remodeling following acute myocardial infarction. We hypothesized that suppression of inflammation with interleukin (IL)-10 treatment attenuates LV dysfunction and remodeling after acute myocardial infarction. After the induction of acute myocardial infarction, mice were treated with either saline or recombinant IL-10, and inflammatory response and LV functional and structural remodeling changes were evaluated. IL-10 significantly suppressed infiltration of inflammatory cells and expression of inflammatory cytokines in the myocardium. These changes were associated with IL-10–mediated inhibition of p38 mitogen-activated protein kinase activation and repression of the cytokine mRNA–stabilizing protein HuR. IL-10 treatment significantly improved LV functions, reduced infarct size, and attenuated infarct wall thinning. Myocardial infarction–induced increase in matrix metalloproteinase (MMP)-9 expression and activity was associated with increased fibrosis because IL-10 treatment reduced both MMP-9 activity and fibrosis. Small interfering knockdown of HuR mimicked IL-10–mediated reduction in MMP-9 expression and activity in NIH3T3 cells. Moreover, IL-10 treatment significantly increased capillary density in the infarcted myocardium which was associated with enhanced STAT3 phosphorylation. Taken together, our studies demonstrate that IL-10 suppresses inflammatory response and contributes to improved LV function and remodeling by inhibiting fibrosis via suppression of HuR/MMP-9 and by enhancing capillary density through activation of STAT3.
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