HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: 2442060599v1 244/2/514    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schäfer, R. Articles by Northoff, H. Search for Related Content PubMed PubMed Citation Articles by Schäfer, R. Articles by Northoff, H.

Transferrin Receptor Upregulation: In Vitro Labeling of Rat Mesenchymal Stem Cells with Superparamagnetic Iron Oxide¹

¹ From the Institute of Clinical and Experimental Transfusion Medicine (R.S., A.G., H.N.) and Departments of Diagnostic Radiology (R.K., J.W., R.B., J.P., C.D.C.), Pathology (H.W.), and Cardiology (B.R.B.), University Medical Center Tübingen, Hoppe-Seyler-Str 3, D-72076 Tübingen, Germany. Received April 4, 2006; revision requested June 2; revision received July 12; accepted August 23; final version accepted November 13. Address correspondence to R.K. (e-mail: rainer.kehlbach{at}med.uni-tuebingen.de).

Purpose: To prospectively evaluate the influence of superparamagnetic iron oxide (SPIO) or ultrasmall SPIO (USPIO) particles on the surface epitope pattern of adult mesenchymal stem cells (MSCs) by regulating the expression of transferrin receptor and to prospectively evaluate the influence of transfection agents (TAs) on the uptake of SPIO or USPIO particles in MSCs.

Materials and Methods: The study was approved by the institutional animal care committee of the University of Tübingen. MSCs were isolated from the bone marrow of four rats. To obtain highly homogeneous MSC populations, MSCs from one rat were single-cell cloned. One MSC clone was characterized and selected for the labeling experiments. The MSCs, which were characterized with flow cytometry and in vitro differentiation, were labeled with 200 µg/mL SPIO or USPIO or with 60 µg/mL SPIO or USPIO in combination with TAs. Aggregations of labeled cells were accommodated inside a defined volume in an agar gel matrix. Magnetic resonance (MR) imaging was performed to measure SPIO- or USPIO-induced signal voids. Quantification of cellular total iron load (TIL) (intracellular iron plus iron coating the cellular surface), determination of cellular viability, and electron microscopy were also performed.

Results: Labeling of MSCs with SPIO or USPIO was feasible without affecting cell viability (91.1%–94.7%) or differentiation potential. For MR imaging, SPIO plus a TA was most effective, depicting 5000 cells with an average TIL of 76.5 pg per cell. SPIO or USPIO particles in combination with TAs coated the cellular surface but were not incorporated into cells. In nontransfected cells, SPIO or USPIO was taken up. MSCs labeled with SPIO or USPIO but without a TA showed enhanced expression of transferrin receptor, in contrary to both MSCs labeled with SPIO or USPIO and a TA and control cells.

Conclusion: SPIO or USPIO labeling without TAs has an influence on gene expression of MSCs upregulating transferrin receptor. Furthermore, SPIO labeling with a TA will coat the cellular surface.

© RSNA, 2007

This article has been cited by other articles:

				E. Pawelczyk and J. A. Frank Transferrin Receptor Expression in Iron Oxide-labeled Mesenchymal Stem Cells Radiology, June 1, 2008; 247(3): 913 - 914. [Full Text] [PDF]

				B. Janic, A. S. Arbab, R. Schafer, R. Kehlbach, and J. Wiskirchen Iron Oxide-Transfection Agent Complexes Are Not Expected to Coat the Cell Membrane and Prevent CD71 Expression Radiology, June 1, 2008; 247(3): 914 - 915. [Full Text] [PDF]