Cardiomyocyte-Specific Overexpression of Nitric Oxide Synthase 3 Improves Left Ventricular Performance and Reduces Compensatory Hypertrophy After Myocardial Infarction

Abstract
Nitric oxide (NO) is an important modulator of cardiac performance and left ventricular (LV) remodeling after myocardial infarction (MI). We tested the effect of cardiomyocyte-restricted overexpression of one NO synthase isoform, NOS3, on LV remodeling after MI in mice. LV structure and function before and after permanent LAD coronary artery ligation were compared in transgenic mice with cardiomyocyte-restricted NOS3 overexpression (NOS3-TG) and their wild-type littermates (WT). Before MI, systemic hemodynamic measurements, echocardiographic assessment of LV fractional shortening (FS), heart weight, and myocyte width (as assessed histologically) did not differ in NOS3-TG and WT mice. The inotropic response to graded doses of isoproterenol was significantly reduced in NOS3-TG mice. One week after LAD ligation, the infarcted fraction of the LV did not differ in WT and NOS3-TG mice (34±4% versus 36±12%, respectively). Four weeks after MI, however, end-systolic LVID was greater, and fractional shortening and ...