Hsienwie Lu

Effects of early treatment with growth hormone on infarct size, survival, and cardiac gene expression after acute myocardial infarction

OBJECTIVE This study examined the effects of growth hormone (GH) on infarct size, survival, and cardiac gene expression in rats with acute myocardial infarction. DESIGN Animals randomly received sc injection of either saline vehicle (n = 98) or GH (2mg/kg/day, n = 105) for 14 days commencing the day of left coronary artery ligation. Infarct size was determined by morphometric analysis at the time of death or at 52 weeks post-surgery. Gene expression was analyzed by real-time RT-PCR after 2-week treatment. RESULTS GH decreased infarct size by 18% (P < 0.01) and increased survival by 36% at 52 weeks. GH also significantly reduced cardiac expression of atrial natriuretic factor, beta-myosin heavy chain, alpha-smooth muscle actin, collagen I, collagen III, fibronectin, and pro-inflammatory cytokines. CONCLUSIONS Treatment with GH for 2 weeks beginning on the day of myocardial infarction produced beneficial effects that were associated with reductions in cardiac gene expression symptomatic of pathological remodeling.