Imaging tumor growth non-invasively using expression of MagA or modified ferritin subunits to augment intracellular contrast for repetitive MRI.

Purpose: The bacterial gene MagA imparts magnetic properties to mammalian cells and provides a basis for cell tracking by magnetic resonance imaging (MRI). In a mouse model of tumor growth from transplanted cells, we used repetitive MRI to demonstrate the in vivo imaging potential of MagA expression relative to a modified ferritin overexpression system, lacking regulation through iron response elements (HF + LF).

Procedures: Subcutaneous tumor xenografts were monitored weekly from days 2 to 34 post-injection.

Using the magnetosome to model effective gene-based contrast for magnetic resonance imaging.

Formation of iron biominerals is a naturally occurring phenomenon, particularly among magnetotactic bacteria which produce magnetite (Fe(3) O(4) ) in a subcellular compartment termed the magnetosome. Under the control of numerous genes, the magnetosome serves as a model upon which to (1) develop gene-based contrast in mammalian cells and (2) provide a mechanism for reporter gene expression in magnetic resonance imaging (MRI). There are two main components to the magnetosome: the biomineral and the lipid bilayer that surrounds it.

Cellular magnetic resonance imaging of monocyte-derived dendritic cell migration from healthy donors and cancer patients as assessed in a scid mouse model.

BACKGROUND AIMS. The use of dendritic cells (DC) as an adjuvant in cell-based immunotherapeutic cancer vaccines is a growing field of interest. A reliable and non-invasive method to track the fate of autologous DC following their administration to patients is required in order to confirm that clinically sufficient numbers are reaching the lymph node (LN).

Labelling dendritic cells with SPIO has implications for their subsequent in vivo migration as assessed with cellular MRI.

An optimized non-invasive imaging modality capable of tracking and quantifying in vivo DC migration in patients would provide clinicians with valuable information regarding therapeutic DC-based vaccine outcomes. Superparamagnetic iron oxide (SPIO) nanoparticles were used to label bone marrow-derived DC. In vivo DC migration was tracked and quantified non-invasively using cellular magnetic resonance imaging (MRI) in a mouse model.

In vivo cellular MRI of dendritic cell migration using micrometer-sized iron oxide (MPIO) particles.

Purpose: This study seeks to assess the use of labeling with micron-sized iron oxide (MPIO) particles for the detection and quantification of the migration of dendritic cells (DCs) using cellular magnetic resonance imaging (MRI).

Procedures: DCs were labeled with red fluorescent MPIO particles for detection by cellular MRI and a green fluorescent membrane dye (PKH67) for histological detection. MPIO-labeled DCs or unlabeled control DCs were injected into mice footpads at two doses (0.