Endothelial nitric oxide synthase overexpression provides a functionally relevant angiogenic switch in hibernating pig myocardium.
OBJECTIVE
We investigated whether retroinfusion of liposomal endothelial nitric oxide synthase (eNOS) S1177D complementary deoxyribonucleic acid (cDNA) would affect neovascularization and function of the ischemic myocardium.


BACKGROUND
Recently, we demonstrated the feasibility of liposomal eNOS cDNA transfection via retroinfusion in a model of acute myocardial ischemia/reperfusion. In the present study, we used this approach to target a phosphomimetic eNOS construct (eNOS S1177D) into chronic ischemic myocardium in a pig model of hibernation.


METHODS
Pigs (n = 6/group) were subjected to percutaneous implantation of a reduction stent graft into the left anterior descending artery (LAD), inducing total occlusion within 28 days. At day 28, retroinfusion of saline solution containing liposomal green fluorescent protein or eNOS S1177D cDNA (1.5 mg/animal, 2 x 10 min) was performed. Furthermore, L-nitroarginine-methylester (L-NAME) was applied orally from day 28, where indicated. At day 28 and day 49, fluorescent microspheres were injected into the left atrium for perfusion analysis. Regional functional reserve (at atrial pacing 140/min) was assessed at day 49 by subendocardial segment shortening (SES) (sonomicrometry, percent of ramus circumflexus region).


RESULTS
The eNOS S1177D overexpression increased endothelial cell proliferation as well as capillary and collateral growth at day 49. Concomitantly, eNOS S1177D overexpression enhanced regional myocardial perfusion from 62 +/- 4% (control) to 77 +/- 3% of circumflex coronary artery-perfused myocardium, unless L-NAME was co-applied (69 +/- 5%). Similarly, eNOS S1177D cDNA improved functional reserve of the LAD (33 +/- 5% vs. 7 +/- 3% of circumflex coronary artery-perfused myocardium), except for L-NAME coapplication (13 +/- 6%).


CONCLUSIONS
Retroinfusion of eNOS S1177D cDNA induces neovascularization via endothelial cell proliferation and collateral growth. The resulting gain of perfusion enables an improved functional reserve of the hibernating myocardium.
Kupatt
Christian
C
Internal Medicine I, Klinikum Grosshadern, Ludwig-Maximilians-University of Munich, Munich, Germany. christian.kupatt@med.uni-muenchen.de
Hinkel
Rabea
R
von Brühl
Marie-Luise
ML
Pohl
Tilmann
T
Horstkotte
Jan
J
Raake
Philip
P
El Aouni
Chiraz
C
Thein
Eckehard
E
Dimmeler
Stefanie
S
Feron
Olivier
O
Boekstegers
Peter
P
D000818:Animals; D017682:Myocardial Stunning / Q000201:enzymology*; D018919:Neovascularization, Physiologic; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis*; D013552:Swine
D052250:Nitric Oxide Synthase Type III