Cell labelling with superparamagnetic iron oxide has no effect on chondrocyte behaviour

Background:. Tissue engineering and regenerative medicine are two rapidly advancing fields of research offering potential for effective treatment of cartilage lesions. Today, chondrocytes are the cell type of choice for use in cartilage repair approaches such as autologous chondrocyte implantation. To verify the safety and efficacy of such approaches it is necessary to determine the fate of these transplanted cells. One way of doing this is prelabelling cells before implantation and tracking them using imaging techniques. The use of superparamagnetic iron oxide (SPIO) for tracking of cells with magnetic resonance imaging (MRI) is ideal for this purpose. It is non-radioactive, does not require viral transfection and is already approved for clinical use as a contrast agent. Objective: The purpose of this study was to assess the effect of SPIO, labelling on adult human chondrocyte behaviour. Methods: Cells were culture expanded and dedifferentiated for two passages and then labelled with SPIO. Effect on cell proliferation was tested. Furthermore, cells were cultured for 21 days in alginate beads in redifferentiation medium. Following this period, cells were analysed for expression of cartilage-related genes, proteoglycan production and collagen protein expression. Results: SPIO labelling did not significantly affect any of these parameters relative to unlabelled controls. We also demonstrated SPIO retention within the cells for the full duration of the experiment. Conclusions: This paper demonstrates for the first time the effects of SPIO labelling on chondrocyte behaviour, illustrating its potential for in vivo tracking of implanted chondrocytes. (C) 2008 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.