[In vitro MR imaging of Fe2O3-arginine labeled heNOS gene modified endothelial progenitor cells].
OBJECTIVE
To explore the feasibility of in vitro magnetic resonance imaging on Fe2O3-arginine labeled heNOS gene modified endothelial progenitor cells (EPCs).


METHODS
Fe2O3 was incubated with arginine to form Fe2O3-arginine complex. Rabbit peripheral blood mononuclear cells (MNCs) were isolated and EPCs were isolated by adherence method, expanded and modified with heNOS gene using Lipofectamine 2000. After 48 hours, genetically modified EPCs were incubated with Fe2O3-arginine for 24 hours. Intracellular iron was detected by Prussian blue stain. The expression of heNOS gene was detected by Western blot. MTT assay was used to evaluate cell survival and proliferation of Fe2O3-arginine labeled heNOS-EPCs. Flow cytometry was used to measure cell apoptosis. The cells underwent in vitro MR imaging with various sequences.


RESULTS
Iron-containing intracytoplasmatic vesicles could be clearly observed with Prussian blue staining, and the labeling rate of labeled heNOS-EPCs were similar to that of labeled EPCs (around 100%). Survival and apoptosis rates obtained by MTT and flow cytometry analysis were similar among labeled heNOS-EPCs, labeled EPCs and unlabeled EPCs with Fe2O3-arginine. The signal intensity on MRI was equally decreased in labeled heNOS-EPCs and labeled EPCs compared with that in unlabeled cells. The percentage change in signal intensity (DeltaSI) was most significant on T2*WI and DeltaSI was significantly lower in cells labeled for 7 days than that labeled for 1 days.


CONCLUSIONS
The heNOS gene can be successfully transfected into rabbit peripheral blood EPCs using Lipofectamine2000. The heNOS-EPCs can be labeled with Fe2O3-arginine without significant change in viability and proliferation capacity. The labeled heNOS-EPCs can be imaged with standard 1.5 T MR equipment. The degree of MR signal intensity may indirectly reflect the cell count, growth and division status.
Nie
Fang
F
Department of Radiology, Zhong Da Hospital, Southeast University, Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Nanjing 210009, China.
Mai
Xiao-li
XL
Chen
Jun
J
Gu
Ning
N
Shi
Hong-jian
HJ
Cao
Ai-hong
AH
Ge
Yu-qing
YQ
Zhang
Yu
Y
Teng
Gao-jun
GJ
D000818:Animals; D042783:Endothelial Cells / Q000166:cytology*; D005290:Ferric Compounds; D006801:Humans; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D052250:Nitric Oxide Synthase Type III / Q000235:genetics*; D011817:Rabbits; D013234:Stem Cells / Q000166:cytology*
D005290:Ferric Compounds; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III