Spin-labeling magnetic resonance imaging detects increased myocardial blood flow after endothelial cell transplantation in the infarcted heart.
BACKGROUND
We quantified absolute myocardial blood flow (MBF) using a spin-labeling MRI (SL-MRI) method after transplantation of endothelial cells (ECs) into the infarcted heart. Our aims were to study the temporal changes in MBF in response to EC transplantation and to compare regional MBF with contractile function (wall motion) and microvascular density.


RESULTS
We first validated the SL-MRI method with the standard microsphere technique in normal rats. We then induced myocardial infarction in athymic rats and injected 5 million ECs (human umbilical vein endothelial cells) suspended in Matrigel or Matrigel alone (vehicle) along the border of the blanched infarcted area. At 2 weeks after myocardial infarction, MBF averaged over the entire slice (P=0.038) and in the infarcted region (P=0.0086) was significantly higher in EC versus vehicle group; the greater MBF was accompanied by an increase of microvasculature density in the infarcted region (P=0.0105 versus vehicle). At 4 weeks after myocardial infarction, MBF in the remote region was significantly elevated in EC-treated hearts (P=0.0277); this was accompanied by increased wall motion in this region assessed by circumferential strains (P=0.0075). Intraclass correlation coefficients and Bland-Altman plot revealed a good reproducibility of the SL-MRI method.


CONCLUSIONS
MBF in free-breathing rats measured by SL-MRI is validated by the standard color microsphere technique. SL-MRI allows quantification of temporal changes of regional MBF in response to EC treatment. The proof-of-principle study indicates that MBF is a unique and sensitive index to evaluate EC-mediated therapy for the infarcted heart.
Laboratories of Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
Hualei
H
Zhang
Hui
H
Qiao
Rachel S
RS
Frank
Bin
B
Huang
Kathleen J
KJ
Propert
Susan
S
Margulies
Victor A
VA
Ferrari
Jonathan A
JA
Epstein
Rong
R
Zhou
D000818:Animals; D002478:Cells, Cultured; D003326:Coronary Circulation; D004195:Disease Models, Animal; D005456:Fluorescent Dyes; D061307:Human Umbilical Vein Endothelial Cells / Q000637:transplantation*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008863:Microspheres; D055806:Microvessels / Q000473:pathology / Q000503:physiopathology; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D051381:Rats; D011923:Rats, Nude; D020127:Recovery of Function; D015203:Reproducibility of Results; D013113:Spin Labels; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left
D005456:Fluorescent Dyes; D013113:Spin Labels