Bone Marrow as a Source of Cells for Paroxysmal Nocturnal Hemoglobinuria Detection.

Objectives: To determine fluorescently labeled aerolysin (FLAER) binding and glycophosphatidylinositol-anchored protein expression in bone marrow (BM) cells of healthy volunteers and patients with paroxysmal nocturnal hemoglobinuria (PNH) detected in peripheral blood (PB); compare PNH clone size in BM and PB; and detect PNH in BM by commonly used antibodies.

Methods: Flow cytometry analysis of FLAER binding to leukocytes and expression of CD55/CD59 in erythrocytes. Analysis of CD16 in neutrophils and CD14 in monocytes in BM.

Quantitative T2* imaging of metastatic human breast cancer to brain in the nude rat at 3 T.

This study uses quantitative T(2)* imaging to track ferumoxides--protamine sulfate (FEPro)-labeled MDA-MB-231BR-Luc (231BRL) human breast cancer cells that metastasize to the nude rat brain. Four cohorts of nude rats were injected intracardially with FEPro-labeled, unlabeled or tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)-treated (to induce apoptosis) 231BRL cells, or saline, in order to develop metastatic breast cancer in the brain. The heads of the rats were imaged serially over 3-4 weeks using gradient multi-echo and turbo spin-echo pulse sequences at 3 T with a solenoid receive-only 4-cm-diameter coil.

Rat model of metastatic breast cancer monitored by MRI at 3 tesla and bioluminescence imaging with histological correlation.

Background: Establishing a large rodent model of brain metastasis that can be monitored using clinically relevant magnetic resonance imaging (MRI) techniques is challenging. Non-invasive imaging of brain metastasis in mice usually requires high field strength MR units and long imaging acquisition times. Using the brain seeking MDA-MB-231BR transfected with luciferase gene, a metastatic breast cancer brain tumor model was investigated in the nude rat.

In vivo transfer of intracellular labels from locally implanted bone marrow stromal cells to resident tissue macrophages.

Intracellular labels such as dextran coated superparamagnetic iron oxide nanoparticles (SPION), bromodeoxyuridine (BrdU) or green fluorescent protein (GFP) are frequently used to study the fate of transplanted cells by in vivo magnetic resonance imaging or fluorescent microscopy. Bystander uptake of labeled cells by resident tissue macrophages (TM) can confound the interpretation of the presence of intracellular labels especially during direct implantation of cells, which can result in more than 70% cell death. In this study we determined the percentages of TM that took up SPION, BrdU or GFP from labeled bone marrow stromal cells (BMSCs) that were placed into areas of angiogenesis and inflammation in a mouse model known as Matrigel plaque perfusion assay.

Optimization and validation of FePro cell labeling method.

Current method to magnetically label cells using ferumoxides (Fe)-protamine (Pro) sulfate (FePro) is based on generating FePro complexes in a serum free media that are then incubated overnight with cells for the efficient labeling. However, this labeling technique requires long (>12-16 hours) incubation time and uses relatively high dose of Pro (5-6 microg/ml) that makes large extracellular FePro complexes. These complexes can be difficult to clean with simple cell washes and may create low signal intensity on T2* weighted MRI that is not desirable.

Diffuse cortical atrophy in a marmoset model of multiple sclerosis.

Marmoset experimental autoimmune encephalomyelitis (EAE) has previously been shown to replicate the essential features of both white matter and grey matter lesions of MS. This study set out to investigate whether cortical atrophy occurs in marmoset EAE and whether cortical thinning is related to the presence of focal, demyelinated cortical lesions. Seventeen leucocortical lesions and 13 subpial lesions were identified in 6 EAE cases.

Synthesis of superparamagnetic nanotubes as MRI contrast agents and for cell labeling.

Aims: Magnetic nanoparticles have been studied widely as MRI contrast agents to increase the sensitivity of this technique. This work describes the synthesis and characterization of magnetic nanotubes (MNTs) as a novel MRI contrast agent.

Methods: MNTs with high saturation magnetization were fabricated by the synthesis of superparamagnetic iron oxide nanoparticles (SPIONs) directly in the pores of silica nanotubes (SNTs).

Demyelinated neocortical lesions in marmoset autoimmune encephalomyelitis mimic those in multiple sclerosis.

The use of immunohistochemical methods has led to a new understanding of the prevalence and significance of cortical lesions in multiple sclerosis but these lesions have not yet been formally described in an animal model. In this study we have set out to use immunohistochemical techniques to identify and describe cortical lesions in marmosets with experimental autoimmune encephalomyelitis (EAE). Using antibodies to proteolipid protein (PLP), we found a total of 70 cortical lesions in 11 tissue blocks from 6 animals.

A model of lysosomal metabolism of dextran coated superparamagnetic iron oxide (SPIO) nanoparticles: implications for cellular magnetic resonance imaging.

Ferumoxides, dextran-coated superparamagnetic iron oxide (SPIO) particles, form ferumoxide-transfection agent (FE-TA) complexes that are internalized into endosomes/lysosomes and have been used to label cells for in vivo MRI tracking and localization studies. A better understanding of the physical state of the FE-TA complexes during endocytosis could improve their use. The purpose of this study was to measure the rate of the degradation of iron particles under varying physiological conditions.

Comparison of transfection agents in forming complexes with ferumoxides, cell labeling efficiency, and cellular viability.

By complexing ferumoxides or superparamagnetic iron oxide (SPIO) to transfection agents (TAs), it is possible to magnetically label mammalian cells. There has been no systematic study comparing TAs complexed to SPIO as far as cell labeling efficiency and viability. This study investigates the toxicity and labeling efficiency at various doses of FEs complexed to different TAs in mammalian cells.

Magnetic resonance imaging of labeled T-cells in a mouse model of multiple sclerosis.

Multiple sclerosis (MS) is a T cell-mediated autoimmune disease with early lesions characterized by mononuclear cellular infiltrate, edema, demyelination, and axonal loss that contribute to the clinical course of the disease. Experimental autoimmune encephalomyelitis (EAE) in the mouse is a valuable model with a similar disease course to relapsing-remitting MS. The ability to detect the migration of encephalitogenic T cells into the central nervous system in EAE and MS would provide key information on these cells role in the development of lesions observed on magnetic resonance imaging (MRI).

Efficient magnetic cell labeling with protamine sulfate complexed to ferumoxides for cellular MRI.

Recently, there have been several reports using various superparamagnetic iron oxide (SPIO) nanoparticles to label mammalian cells for monitoring their temporal and spatial migration in vivo by magnetic resonance imaging (MRI). The purpose of this study was to evaluate the efficiency and toxicity of labeling cells using 2 commercially available Food and Drug Administration (FDA)-approved agents, ferumoxides, a suspension of dextran-coated SPIO used as an MRI contrast agent, and protamine sulfate, conventionally used to reverse heparin anticoagulation but also used ex vivo as a cationic transfection agent. After labeling of human mesenchymal stem cells (MSCs) and hematopoietic (CD34+) stem cells and other mammalian cells with ferumoxides-protamine sulfate complexes (FE-Pro), cellular toxicity, functional capacity, and quantitative cellular iron incorporation were determined.

In vivo trafficking and targeted delivery of magnetically labeled stem cells.

Targeted delivery of intravenously administered genetically altered cells or stem cells is still in an early stage of investigation. We developed a method of delivering iron oxide (ferumoxide)-labeled mesenchymal stem cells (MSCs) to a targeted area in an animal model by applying an external magnet. Rats with or without an external magnet placed over the liver were injected intravenously with ferumoxide-labeled MSCs and magnetic resonance imaging (MRI) signal intensity (SI) changes, iron concentration, and concentration of MSCs in the liver were monitored at different time points.

Characterization of biophysical and metabolic properties of cells labeled with superparamagnetic iron oxide nanoparticles and transfection agent for cellular MR imaging.

Purpose: To evaluate the effect of using the ferumoxides-poly-l-lysine (PLL) complex for magnetic cell labeling on the long-term viability, function, metabolism, and iron utilization of mammalian cells.

Materials And Methods: PLL was incubated with ferumoxides for 60 minutes, incompletely coating the superparamagnetic iron oxide (SPIO) through electrostatic interactions. Cells were coincubated overnight with the ferumoxides-PLL complex, and iron uptake, cell viability, apoptosis indexes, and reactive oxygen species formation were evaluated.

Intracytoplasmic tagging of cells with ferumoxides and transfection agent for cellular magnetic resonance imaging after cell transplantation: methods and techniques.

Background: Superparamagnetic iron oxides (SPIO) are being used to label cells for in vivo monitoring by magnetic resonance imaging (MRI). The purpose of this study is to present protocols using SPIO and a polycationic transfection agent for magnetic labeling of cells as a basis for cellular MRI.

Methods: Various concentrations of ferumoxides (FE)-poly-l-lysine (PLL) complexes were used to magnetically label cells.