Abstract 13649: Chronic Vagal Stimulation Promotes Cardiac Regeneration by Activation of Endogenous Cardiac Stem Cells in Rats after Acute Myocardial Infarction
Introduction: We have demonstrated that chronic vagal stimulation (VS) prevented the progression of cardiac remodeling and death in post myocardial infarction (MI) rats. However, the precise mechanisms of cardiac protection by VS have not been fully elucidated. We hypothesized that VS preserves cardiac function partly through activation of endogenous cardiac stem cells (CSCs) after acute MI.
Methods: An ECG transmitter and a radio-controlled vagal stimulator were implanted in rats. Survived MI rats (n=44) were performed VS (0.2ms, 20Hz, 0.1-0.13mA) or sham-stimulation (SS) one hour after left coronary artery ligation. At the end of 4 weeks treatment, the outcome of VS was evaluated by echocardiography, cardiac catheterization, neurohumoral states, immunohistochemistry and histological examination. Activation of endogenous CSCs in the heart was assessed by the number of c-kit positive cells.
Results: VS significantly improved cardiac function (table).The c-kit positive cells were higher in VS group (+120%) than in SS group. Apoptotic c-kit positive cells were lower in VS group (-67%) than in SS group. Capillary density as shown v-WF positive cells in the peri-infarct area was higher in VS group (+55%) than in SS group. Double staining of the sections for cardiac-specific proteins showed that c-kit positive cells expressed myosin heavy chain, cardiac troponin I, desmin, connexin-43, v-WF and α-smooth muscle actin.
Conclusion: The preservation of cardiac function by VS in acute myocardial infarction rats may be mediated partly by cardiac regeneration through activation of endogenous CSCs and induction of angiogenesis.
- © 2012 by American Heart Association, Inc.