In vivo visualization of embryonic stem cell survival, proliferation, and migration after cardiac delivery.
BACKGROUND
Recent studies have shown that stem cell therapy can promote tissue regeneration; however, monitoring stem cells in vivo remains problematic owing to limitations of conventional histological assays and imaging modalities.


RESULTS
Murine embryonic stem (ES) cells were stably transduced with a lentiviral vector carrying a novel triple-fusion (TF) reporter gene that consists of firefly luciferase, monomeric red fluorescence protein, and truncated thymidine kinase (fluc-mrfp-ttk). ES cell viability, proliferation, and differentiation ability were not adversely affected by either reporter genes or reporter probes compared with nontransduced control cells (P=NS). Afterward, 1x10(7) of ES cells carrying the TF reporter gene (ES-TF) were injected into the myocardium of adult nude rats (n=20). Control animals received nontransduced ES cells (n=6). At day 4, the bioluminescence and positron emission tomography signals in study animals were 3.7x10(7)+/-5.8x10(6) photons.s(-1).cm(-2) per steradian (sr) and 0.08+/-0.03% injected dose/g, respectively (P<0.05 versus control). Both signals increased progressively from week 1 to week 4, which indicated ES cell survival and proliferation in the host. Histological analysis demonstrated the formation of intracardiac and extracardiac teratomas. Finally, animals (n=4) that were treated with intraperitoneal injection of ganciclovir (50 mg/kg) did not develop teratomas when compared with control animals (n=4) treated with saline (1 mL/kg).


CONCLUSIONS
This is the first study to characterize ES cells that stably express fluorescence, bioluminescence, and positron emission tomography reporter genes and monitor the kinetics of ES cell survival, proliferation, and migration. This versatile imaging platform should have broad applications for basic research and clinical studies on stem cell therapy.
Department of Radiology, Bio-X Program, Stanford University School of Medicine, Stanford, CA 94305-5344, USA.
Feng
F
Cao
Shuan
S
Lin
Xiaoyan
X
Xie
Pritha
P
Ray
Manishkumar
M
Patel
Xianzhong
X
Zhang
Micha
M
Drukker
Scott J
SJ
Dylla
Andrew J
AJ
Connolly
Xiaoyuan
X
Chen
Irving L
IL
Weissman
Sanjiv S
SS
Gambhir
Joseph C
JC
Wu
D000818:Animals; D002465:Cell Movement; D049109:Cell Proliferation; D002470:Cell Survival; D004622:Embryo, Mammalian / Q000166:cytology; D015774:Ganciclovir / Q000627:therapeutic use; D017930:Genes, Reporter; D006801:Humans; D049449:Luminescence; D051379:Mice; D023421:Models, Animal; D009206:Myocardium / Q000166:cytology*; D049268:Positron-Emission Tomography; D011292:Premedication; D051381:Rats; D012038:Regeneration; D033581:Stem Cell Transplantation / Q000009:adverse effects / Q000379:methods*; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology; D013724:Teratoma / Q000209:etiology / Q000517:prevention & control; D014161:Transduction, Genetic; D014183:Transplantation, Heterologous
D015774:Ganciclovir