Abstract 128: Patches Of Atrial Appendage Tissue Improve Ventricular Function After Myocardial Infarction
Introduction: Atrial appendage (AA) is an expendable autologous tissue source containing cardiomyocytes, inherent cardiac progenitors, and endothelial cells. We hypothesize that AA tissue can be employed as a unique hormonally-active external patch for infarct repair and that inducing the cytoprotective factor, heme oxygenase-1 (HO-1), would enhance survival in transplanted patch cardiomyocytes.
Methods: AA patches (5x7mm) were transplanted from donor F344 rats onto hearts in isogenic recipients immediately after acute myocardial infarction (MI). Recipient rats were randomized to receive acute MI only, or external AA patches from donors pretreated with PBS or with the HO-1 inducer, cobalt protoporphyrin (CoPP), 5mg/kg, 24 hrs prior to AA harvest (n=9/group). Echocardiography was performed at baseline and at 4 wks, at which point hearts were excised and fixed for image analysis.
Results: At 4 wks post-MI, % fractional shortening was 41% higher (P < 0.01) in HO-1-induced and 32% higher (P = 0.03) in PBS-treated AA patch implant groups vs. MI-only controls. In atrial patches, HO-1 induction significantly reduced collagen deposition compared to PBS-pretreated patches (10 ± 3% vs. 16 ± 5% of ventricular area, P < 0.05), increased atrial cardiomyocyte-containing graft area by 35% (Fig. 1), and preserved connexin 43 expression in atrial grafts.
Conclusions: External implantation of cardiomyocyte patches derived from AA tissue increased ventricular function after acute MI. Preemptive induction of pro-survival factor HO-1 showed additional advantages in preserving cardiomyocyte mass and gap junctions, and reducing fibrosis in transplanted cardiomyocyte patches.
- © 2013 by American Heart Association, Inc.