Adenoviral human BCL-2 transgene expression attenuates early donor cell death after cardiomyoblast transplantation into ischemic rat hearts.
BACKGROUND
Cell transplantation for myocardial repair is limited by early cell death. Gene therapy with human Bcl-2 (hBcl-2) has been shown to attenuate apoptosis in the experimental setting. Therefore, we studied the potential benefit of hBcl-2 transgene expression on the survival of cardiomyoblast grafts in ischemic rat hearts.


RESULTS
H9c2 rat cardiomyoblasts were genetically modified to express both firefly luciferase and green fluorescent protein (mH9c2). The cells were then transduced with adenovirus carrying hBcl-2 (AdCMVhBcl-2/mH9c2). Lewis rats underwent ligation of the left anterior descending artery (LAD) to induce a sizable left ventricular (LV) infarct. Hearts were explanted and the infarcted region was restored using collagen matrix (CM) seeded with 1x10(6) mH9c2 cells (n=9) or AdCMVhBcl-2/mH9c2 cells (n=9). Control animals received CM alone (n=6) or no infarct (n=6). Restored hearts were transplanted into the abdomen of syngeneic recipients in a "working heart" model. Cell survival was evaluated using optical bioluminescence imaging on days 1, 5, 8, 14, and 28 after surgery. The left heart function was assessed 4 weeks postoperatively using echocardiography and magnetic resonance imaging. During 4 weeks after surgery, the optical imaging signal for the AdCMVhBCL2/mH9c2 group was significantly (P<0.05) higher than that of the mH9c2-control group. Both grafts led to better fractional shortening (AdCMVhBcl-2/mH9c2: 0.21+/-0.03; mH9c2: 0.21+/-0.04; control: 0.15+/-0.03; P=0.04) and ejection fraction (AdCMVhBcl-2/mH9c2: 47.0+/-6.2; mH9c2: 48.7+/-6.1; control: 34.3+/-6.0; P=0.02) compared with controls. Importantly, no malignant cells were found in postmortem histology.


CONCLUSIONS
Transduction of mH9c2 cardiomyoblasts with AdCMVhBcl-2 increased graft survival in ischemic rat myocardium without causing malignancies. Both AdCMVhBcl-2/mH9c2 and mH9c2 grafts improved LV function.
Kutschka
Ingo
I
Department of Cardiothoracic Surgery, Stanford University, School of Medicine, Stanford, California, USA. ingo.kutschka@t-online.de
Kofidis
Theo
T
Chen
Ian Y
IY
von Degenfeld
Georges
G
Zwierzchoniewska
Monika
M
Hoyt
Grant
G
Arai
Takayasu
T
Lebl
Darren R
DR
Hendry
Stephen L
SL
Sheikh
Ahmad Y
AY
Cooke
David T
DT
Connolly
Andrew
A
Blau
Helen M
HM
Gambhir
Sanjiv S
SS
Robbins
Robert C
RC
D000005:Abdomen; D000007:Abdominal Injuries / Q000473:pathology / Q000628:therapy; D034861:Abdominal Wall / Q000473:pathology; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D003080:Cold Temperature / Q000009:adverse effects; D003094:Collagen / Q000494:pharmacology; D003673:Defective Viruses / Q000235:genetics; D017930:Genes, Reporter; D019254:Genes, bcl-2; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000627:therapeutic use; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D032446:Myoblasts / Q000637:transplantation*; D009203:Myocardial Infarction / Q000628:therapy*; D032383:Myocytes, Cardiac / Q000637:transplantation*; D051381:Rats; D011917:Rats, Inbred Lew; D019076:Transgenes; D016042:Transplantation, Heterotopic; D016277:Ventricular Function, Left
D003094:Collagen