Comparison of SPIO and USPIO for in vitro labeling of human monocytes: MR detection and cell function.
ABSTRACT To label human monocytes with superparamagnetic iron oxide (SPIO) and compare labeling efficiency with that of ultrasmall SPIO (USPIO) and evaluate the effect of iron incorporation on cell viability, migratory capacity, and proinflammatory cytokine production.
The study was approved by the institutional ethics committee; informed consent was obtained from donors. Freshly isolated human monocytes were labeled with iron particles of two sizes, USPIOs of 30 nm and SPIOs of 150 nm, for 1.5 hours in culture medium containing 0.1, 0.5, 1.0, and 3.7 mg of iron per milliliter. Labeling efficiency was determined with relaxation time magnetic resonance (MR) imaging (4.7 T) and Prussian blue staining for presence of intracellular iron. Cell viability was monitored; migratory capacity of monocytes after labeling was evaluated by using an in vitro assay with monolayers of brain endothelial cells. Levels of proinflammatory cytokines, interleukin (IL) 1 and IL-6, were measured with enzyme-linked immunosorbent assay 24 hours after labeling. Data were analyzed with Student t test or two-way analysis of variance followed by a multiple-comparison procedure.
R2 relaxation rates increased for cell samples incubated with SPIOs, whereas rates were not affected for samples incubated with highest concentration of USPIOs. Labeling monocytes with SPIOs (1.0 mg Fe/mL) resulted in an R2 of 13.1 sec(-1) +/- 0.8 (standard error of the mean) (7 sec(-1) +/- 0.2 for vehicle-treated cells, P < .05) and had no effect on cell viability. On the basis of T2 relaxation times, the in vitro MR detection limit of 58 labeled monocytes per 0.05 microL was calculated. Migration of labeled monocytes was not different from that of vehicle-treated cells. Intracellular iron had no effect on production of IL-1 and IL-6 24 hours after labeling.
In vitro labeling of human monocytes is effective by using SPIOs, not USPIOs. Incubation with SPIOs (1.0 mg Fe/mL) results in efficient labeling detectable on MR images and does not affect cellular viability and activation markers such as cell migration and cytokine production.
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ABSTRACT: Ferumoxytol is an ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle that is FDA-approved as an intravenous iron replacement therapy for the treatment of iron deficiency anemia in patients with chronic kidney disease. Ferumoxytol has also been used as a contrast agent for cerebral blood volume mapping by magnetic resonance imaging (MRI), which suggests it could be used for imaging hemodynamic abnormalities after stroke. However, circulating macrophages can internalize USPIOs, and recent data indicate that the accumulation of iron in macrophages can lead them to adopt the M1 pro-inflammatory phenotype. Therefore, the uptake of intravenously administered iron particles by circulating macrophages that home to the stroke core could potentially alter the inflammatory response to stroke. To test this possibility in vivo we administered a dose of ferumoxytol previously used to obtain cerebral blood volume maps in healthy humans by steady-state susceptibility contrast (SSC) MRI to BALB/cJ mice 48h after stroke and examined cytokine levels, microglial/macrophage activation, and lesion volume in the brain 5 days later. Treatment with ferumoxytol did not lead to any differences in these parameters. These data indicate that the use of ferumoxytol as a contrast agent for brain imaging after stroke does not alter the inflammatory response to stroke in mice, and is therefore unlikely to do so in human subjects. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.Neuroscience Letters 11/2014; 584C:236-240. DOI:10.1016/j.neulet.2014.10.041 · 2.06 Impact Factor
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ABSTRACT: An aptamer (Apt) conjugated hyaluronan/chitosan nanoparticles (HACSNPs) were prepared as carrier for targeted delivery of 5-fluorouracil (5FU) to mucin1 (MUC1) overexpressing colorectal adenocarcinomas. Nanoparticles had about 181 nm size, encapsulation efficiency of 45.5 ± 2.8 and acceptable stability. Conjugation of MUC1-binding Apt to the surface of the nanoparticles was confirmed by gel electrophoresis. Toxicity and cellular uptake of nanoparticles were investigated by in vitro cytotoxicity assays and confocal scanning microscopy in (MUC1+) human adenocarcinoma and (MUC1−) Chinese hamster ovary cells. Toxicity of nanoparticles were significantly higher in comparison with free drug in both cell lines while this rising was more efficient for nanoparticles decorated with Apt in MUC1+ cell line. The same result was observed in the cellular uptake study. It could be concluded that the present system has the potential to be considered in treatment of MUC1+ colorectal adenocarcinomas.Carbohydrate Polymers 05/2015; 121. DOI:10.1016/j.carbpol.2014.12.025 · 3.92 Impact Factor
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ABSTRACT: The physicochemical properties of superparamagnetic iron oxide nanoparticles (SPIOs) enable their application in the diagnostics and therapy of central nervous system diseases. However, since crucial information regarding side effects of particle-cell interactions within the central nervous system is still lacking, we investigated the influence of novel very small iron oxide particles or the clinically approved ferucarbotran or ferumoxytol on the vitality and morphology of brain cells. We exposed primary cell cultures of microglia and hippocampal neurons, as well as neuron-glia cocultures to varying concentrations of SPIOs for 6 and/or 24 hours, respectively. Here, we show that SPIO accumulation by microglia and subsequent morphological alterations strongly depend on the respective nanoparticle type. Microglial viability was severely compromised by high SPIO concentrations, except in the case of ferumoxytol. While ferumoxytol did not cause immediate microglial death, it induced severe morphological alterations and increased degeneration of primary neurons. Additionally, primary neurons clearly degenerated after very small iron oxide particle and ferucarbotran exposure. In neuron-glia cocultures, SPIOs rather stimulated the outgrowth of neuronal processes in a concentration- and particle-dependent manner. We conclude that the influence of SPIOs on brain cells not only depends on the particle type but also on the physiological system they are applied to.International Journal of Nanomedicine 01/2015; 10:2033-49. DOI:10.2147/IJN.S74404 · 4.20 Impact Factor