Cong Chen, Abstract Co-Author: Nothing to Disclose

Hong Yu MD, PhD, Abstract Co-Author: Nothing to Disclose

Rui Xia, Abstract Co-Author: Nothing to Disclose

Xiangsheng Xiao PhD, Abstract Co-Author: Nothing to Disclose

Fabao Gao MD, PhD, Abstract Co-Author: Nothing to Disclose

Jichun Liao, Abstract Co-Author: Nothing to Disclose

Shize Jiang, Presenter: Nothing to Disclose

To assess the feasibility of labeling endothelial progenitor cells (EPCs) with polyethylenimine 2kDa-superparamagnetic iron oxide (PEI2k-SPIO), thereby tracking of EPCs in a lung carcinoma xenograft model by using 7.0 T MR.

Protocols for sampling human peripheral blood were approved by Institute’s Ethics Review Committee and animal experiments were approved by Institute’s Animal Care and Use Committee. EPCs were derived from human peripheral blood and labeled with PEI2k-SPIO. EPCs viability and activity after labeling were evaluated in vitro. MRI study of labeled EPCs agarose hygrogels was performed at 7.0 T Micro-MR using MSME-T2 map and MGE-T2* map. Labeled EPCs were injected intravenously 7 days after inoculation of A549 lung cancer cells subcutaneously (group A, n=6) or co-injected subcutaneously with A549 cells (group B, n=6) while A549 cells were inoculated subcutaneously without EPCs as control (group C, n=6). A four-week follow-up was performed by MR imaging with TurboRARE-T2 and MGE-T2*. Statistical analyses were performed with Student’s t-test.

Labeling efficacy of EPCs was almost 100%, and cellular iron content was 6.062±0.050pg/cell. No significant effects on EPCs viability and activity were found after labeling. In MRI study in vitro, both signal intensity (SI) and relaxation times displayed significant differences (P<0.01) between T2 and T2* imaging. In MRI study in vivo, schistic or linear hypointense regions were observed at tumor margins at day 7 or 8 after EPCs administration and gradually extended into the inner of tumor in group A while low signal intensity regions dispersed inside the tumor with its growth in group B. The results were confirmed by Prussian blue staining and immunofluorescence.

PEI2k-SPIO can label EPCs efficiently without cellular alteration. 7.0 T MR imaging provides a noninvasive technique for tracing EPCs homing specifically to sites of lung carcinoma xenografts and involving in tumor neovasculature.

(Dealing with SPIO-MRI) “Stem cells labeled with SPIO allow noninvasive tracing in vivo with MR imaging and is recommended in the evaluation of stem cell-transplantation.”

Chen, C, Yu, H, Xia, R, Xiao, X, Gao, F, Liao, J, Jiang, S, Tracking of Human Peripheral Blood Endothelial Progenitor Cells Labeled with PEI2k-SPIO in a Lung Carcinoma Xenograft Model by 7.0 T MR Imaging.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12026502.html