Labeling of cynomolgus monkey bone marrow-derived mesenchymal stem cells for cell tracking by multimodality imaging

Incorporation of Superparamagnetic Magnetic–Fluorescent Iron Oxide Nanoparticles Increases Proliferation of Human Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have significant therapeutic potential and their use requires in-depth studies to better understand their effects. Labeling cells with superparamagnetic iron oxide nanoparticles allows real-time monitoring of their location, migration, and fate post-transplantation. This study aimed to investigate the efficacy and cytotoxicity of magnetic–fluorescent nanoparticles in human adipose tissue-derived mesenchymal stem cells (hADSCs). The efficacy of Molday ION rhodamine B (MIRB) labeling in hADSCs was evaluated and their biocompatibility was assessed using various techniques and differentiation assays. Prussian blue and fluorescence staining confirmed that 100% of the cells were labeled with MIRB and this labeling persisted for at least 3 days. Transmission electron microscopy revealed the internalization and clustering of the nanoparticles on the outer surface of the cell membrane. The viability assay showed increased cell viability 3 days after nanoparticle exposure. Cell counts were higher in the MIRB-treated group compared to the control group at 3 and 5 days and an increased cell proliferation rate was observed at 3 days post-exposure. Adipogenic, osteogenic, and chondrogenic differentiation was successfully achieved in all groups, with MIRB-treated cells showing an enhanced differentiation rate into adipocytes and osteocytes. MIRB was efficiently internalized by hADSCs but induced changes in cellular behavior due to the increased cell proliferation rate.

Nanotechnology-Assisted Cell Tracking

The usefulness of nanoparticles (NPs) in the diagnostic and/or therapeutic sector is derived from their aptitude for navigating intra- and extracellular barriers successfully and to be spatiotemporally targeted. In this context, the optimization of NP delivery platforms is technologically related to the exploitation of the mechanisms involved in the NP-cell interaction. This review provides a detailed overview of the available technologies focusing on cell-NP interaction/detection by describing their applications in the fields of cancer and regenerative medicine. Specifically, a literature survey has been performed to analyze the key nanocarrier-impacting elements, such as NP typology and functionalization, the ability to tune cell interaction mechanisms under in vitro and in vivo conditions by framing, and at the same time, the imaging devices supporting NP delivery assessment, and consideration of their specificity and sensitivity. Although the large amount of literature information on the designs and applications of cell membrane-coated NPs has reached the extent at which it could be considered a mature branch of nanomedicine ready to be translated to the clinic, the technology applied to the biomimetic functionalization strategy of the design of NPs for directing cell labelling and intracellular retention appears less advanced. These approaches, if properly scaled up, will present diverse biomedical applications and make a positive impact on human health.

Superparamagnetic Iron Oxide Nanoparticles: Cytotoxicity, Metabolism, and Cellular Behavior in Biomedicine Applications

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely investigated and applied in the field of biomedicine due to their excellent superparamagnetic properties and reliable traceability. However, with the optimization of core composition, shell types and transfection agents, the cytotoxicity and metabolism of different SPIONs have great differences, and the labeled cells also show different cellular behaviors. Therefore, a holistic review of the construction and application of SPIONs is desired. This review focuses the advances of SPIONs in the field of biomedicine in recent years. After summarizing the toxicity of different SPIONs, the uptake, distribution and metabolism of SPIONs in vitro were discussed. Then, the regulation of labeled-cells behavior is outlined. Furthermore, the major challenges in the optimization process of SPIONs and insights on its future developments are proposed.

Effects of labeling human mesenchymal stem cells with superparamagnetic zinc-nickel ferrite nanoparticles on cellular characteristics and adipogenesis/osteogenesis differentiation

OBJECTIVE

An attractive cell source for stem cell-based therapy are WJ-MSCs. Hence, tracking WJ-MSCs using non-invasive imaging procedures (such as MRI) and contrast agents (Zn0.5Ni0.5Fe2O4, NFNPs) are required to evaluate cell distribution, migration, and differentiation.

RESULTS

Results showed that the bare and dextrin-coated NFNPs were internalized inside the WJ-MSCs and had no effect on the cell viability, proliferation, apoptosis, karyotyping, and morphology of WJ-MSCs up to 125 µg/mL. Besides, treated WJ-MSCs were differentiated into osteo/adipocyte-like cells. The expression of RUNX 2, SPP 1 (P < 0.05), and OCN (P > 0.05) genes in the WJ-MSCs treated with dextrin-coated NFNPs was higher than the untreated WJ-MSCs; and the expression of CFD, LPL, and PPAR-γ genes was reduced in WJ-MSCs treated with both NFNPs in comparison with the untreated WJ-MSCs (P > 0.05).

CONCLUSION

Overall, results showed that dextrin-coated NFNPs had no adverse effect on the cellular characteristics, proliferation, and differentiation of WJ-MSCs, and suggesting their potential clinical efficacy.

Dextran-coated iron oxide nanoparticle-induced nanotoxicity in neuron cultures

Recent technological advances have introduced diverse engineered nanoparticles (ENPs) into our air, water, medicine, cosmetics, clothing, and food. However, the health and environmental effects of these increasingly common ENPs are still not well understood. In particular, potential neurological effects are one of the most poorly understood areas of nanoparticle toxicology (nanotoxicology), in that low-to-moderate neurotoxicity can be subtle and difficult to measure. Culturing primary neuron explants on planar microelectrode arrays (MEAs) has emerged as one of the most promising in vitro techniques with which to study neuro-nanotoxicology, as MEAs enable the fluorescent tracking of nanoparticles together with neuronal electrical activity recording at the submillisecond time scale, enabling the resolution of individual action potentials. Here we examine the dose-dependent neurotoxicity of dextran-coated iron oxide nanoparticles (dIONPs), a common type of functionalized ENP used in biomedical applications, on cultured primary neurons harvested from postnatal day 0-1 mouse brains. A range of dIONP concentrations (5-40 µg/ml) were added to neuron cultures, and cells were plated either onto well plates for live cell, fluorescent reactive oxidative species (ROS) and viability observations, or onto planar microelectrode arrays (MEAs) for electrophysiological measurements. Below 10 µg/ml, there were no dose-dependent cellular ROS increases or effects in MEA bursting behavior at sub-lethal dosages. However, above 20 µg/ml, cell death was obvious and widespread. Our findings demonstrate a significant dIONP toxicity in cultured neurons at concentrations previously reported to be safe for stem cells and other non-neuronal cell types.

In-vitro Labelling of Ovine Adipose-Derived Mesenchymal Stem Cells (oADMSCs) and Tracking Using MRI Technique

To understand the mechanisms standing behind a successful stem cell-based therapy, the monitoring of transplanted cell’s migration, homing as well as the engraftment efficiency and functional capability in-vivo has become a critical issue. The present study was designed to track the labelled oADMSCs in-vitro and its visualization through MRI technique. oADMSCs from passage 4 (P-4) to passage 6 (P-6) were labelled with superparamagnetic iron oxide (SPIO) conjugated with rhodamine (Molday Ion Rhodamine-B - MIRB) at the concentration of 25μg Fe/ml in DMEM. Internalized MIRB was observed under fluorescent microscope after 72 hrs of incubation. Labelled oADMSCs showed Prussian Blue positive reaction demonstrating the iron uptake of the cells. The viability of the MIRB-labelled oADMSCs ranged between 98-99 per cent and Trypan blue exclusion test showed no significant difference in viability between labelled and unlabelled oADMSCs. MR signal in control group of cells was similar to that of water. MR signals or fluorescence in MIRB-labelled cells decreased with increasing concentrations of iron. The T2 weighted images of MIRB-labelled oADMSCs increased with increasing concentrations of SPIOs. The MIRB was found to be nontoxic, and did not affect proliferation capacity in-vitro.

Biological Characteristics of Fluorescent Superparamagnetic Iron Oxide Labeled Human Dental Pulp Stem Cells

Tracking transplanted stem cells is necessary to clarify cellular properties and improve transplantation success. In this study, we investigate the effects of fluorescent superparamagnetic iron oxide particles (SPIO) (Molday ION Rhodamine-B™, MIRB) on biological properties of human dental pulp stem cells (hDPSCs) and monitor hDPSCs in vitro and in vivo using magnetic resonance imaging (MRI). Morphological analysis showed that intracellular MIRB particles were distributed in the cytoplasm surrounding the nuclei of hDPSCs. 12.5–100 μg/mL MIRB all resulted in 100% labeling efficiency. MTT showed that 12.5–50 μg/mL MIRB could promote cell proliferation and MIRB over 100 μg/mL exhibited toxic effect on hDPSCs. In vitro MRI showed that 1 × 10⁶ cells labeled with various concentrations of MIRB (12.5–100 μg/mL) could be visualized. In vivo MRI showed that transplanted cells could be clearly visualized up to 60 days after transplantation. These results suggest that 12.5–50 μg/mL MIRB is a safe range for labeling hDPSCs. MIRB labeled hDPSCs cell can be visualized by MRI in vitro and in vivo. These data demonstrate that MIRB is a promising candidate for hDPSCs tracking in hDPSCs based dental pulp regeneration therapy.

The Preclinical Research Progress of Stem Cells Therapy in Parkinson's Disease

Parkinson's disease (PD) is a type of degenerative disorder of the basal ganglia, causing tremor at rest, muscle rigidity hypokinesia, and dementia. The effectiveness of drug treatments gradually diminishes because the conversion to dopamine within the brain is increasingly disrupted by the progressive degeneration of the dopaminergic terminals. After long-term treatment, most patients with PD suffer from disability that cannot be satisfactorily controlled. To solve these issues, stem cells have recently been used for cell therapy of PD. In this review, the characteristics of different stem cells and their therapeutic effects on PD treatment will be discussed.

SIRB, sans iron oxide rhodamine B, a novel cross-linked dextran nanoparticle, labels human neuroprogenitor and SH-SY5Y neuroblastoma cells and serves as a USPIO cell labeling control

This is the first report of the synthesis of a new nanoparticle, sans iron oxide rhodamine B (SIRB), an example of a new class of nanoparticles. SIRB is designed to provide all of the cell labeling properties of the ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle Molday ION Rhodamine B (MIRB) without containing the iron oxide core. MIRB was developed to label cells and allow them to be tracked by MRI or to be manipulated by magnetic gradients. SIRB possesses a similar size, charge and cross-linked dextran coating as MIRB. Of great interest is understanding the biological and physiological changes in cells after they are labeled with a USPIO. Whether these effects are due to the iron oxide buried within the nanoparticle or to the surface coating surrounding the iron oxide core has not been considered previously. MIRB and SIRB represent an ideal pairing of nanoparticles to identify nanoparticle anatomy responsible for post-labeling cytotoxicity. Here we report the effects of SIRB labeling on the SH-SY5Y neuroblastoma cell line and primary human neuroprogenitor cells (hNPCs). These effects are contrasted with the effects of labeling SH-SY5Y cells and hNPCs with MIRB. We find that SIRB labeling, like MIRB labeling, (i) occurs without the use of transfection reagents, (ii) is packaged within lysosomes distributed within cell cytoplasm, (iii) is retained within cells with no loss of label after cell storage, and (iv) does not alter cellular viability or proliferation, and (v) SIRB labeled hNPCs differentiate normally into neurons or astrocytes. Copyright © 2016 John Wiley & Sons, Ltd.

Cell-Based Therapy in TBI: Magnetic Retention of Neural Stem Cells In Vivo

Stem cell therapy is under active investigation for traumatic brain injury (TBI). Noninvasive stem cell delivery is the preferred method, but retention of stem cells at the site of injury in TBI has proven challenging and impacts effectiveness. To investigate the effects of applying a magnetic field on cell homing and retention, we delivered human neuroprogenitor cells (hNPCs) labeled with a superparamagnetic nanoparticle into post-TBI animals in the presence of a static magnetic field. We have previously devised a method of loading hNPCs with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles Molday ION Rhodamine B (MIRB™). Labeling of hNPCs (MIRB-hNPCs) does not affect hNPC viability, proliferation, or differentiation. The 0.6 tesla (T) permanent magnet was placed ∼4 mm above the injured parietal cortex prior to intracarotid injection of 4 × 10(4) MIRB-hNPCs. Fluorescence imaging, Perls' Prussian blue histochemistry, immunocytochemistry with SC121, a human-specific antibody, and T2-weighted magnetic resonance imaging ex vivo revealed there was increased homing and retention of MIRB-hNPCs in the injured cortex as compared to the control group in which MIRB-hNPCs were injected in the absence of a static magnetic field. Fluoro-Jade C staining and immunolabeling with specific markers confirmed the viability status of MIRB-hNPCs posttransplantation. These results show that increased homing and retention of MIRB-hNPCs post-TBI by applying a static magnetic field is a promising technique to deliver cells into the CNS for treatment of neurological injuries and neurodegenerative diseases.

Effect of HSA coated iron oxide labeling on human umbilical cord derived mesenchymal stem cells

Human umbilical cord derived mesenchymal stem cells (hUC-MSCs) are known for self-renewal and differentiation into cells of various lineages like bone, cartilage and fat. They have been used in biomedical applications to treat degenerative disorders. However, to exploit the therapeutic potential of stem cells, there is a requirement of sensitive non-invasive imaging techniques which will offer the ability to track transplanted cells, bio-distribution, proliferation and differentiation. In this study, we have analyzed the efficacy of human serum albumin coated iron oxide nanoparticles (HSA-IONPs) on the differentiation of hUC-MSCs. The colloidal stability of the HSA-IONPs was tested over a long period of time (≥20 months) and the optimized concentration of HSA-IONPs for labeling the stem cells was 60 μg ml(-1). Detailed in vitro assays have been performed to ascertain the effect of the nanoparticles (NPs) on stem cells. Lactate dehydrogenase (LDH) assay showed minimum release of LDH depicting the least disruptions in cellular membrane. At the same time, mitochondrial impairment of the cells was also not observed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry analysis revealed lesser generation of reactive oxygen species in HSA-IONPs labeled hUC-MSCs in comparison to bare and commercial IONPs. Transmission electron microscopy showed endocytic engulfment of the NPs by the hUC-MSCs. During the process, the gross morphologies of the actin cytoskeleton were found to be intact as shown by immunofluorescence microscopy. Also, the engulfment of the HSA-IONPs did not show any detrimental effect on the differentiation potential of the stem cells into adipocytes, osteocytes and chondrocytes, thereby confirming that the inherent properties of stem cells were maintained.

Evaluation of ultrasmall superparamagnetic iron oxide contrast agent labeling of equine cord blood and bone marrow mesenchymal stromal cells

OBJECTIVE

To evaluate the efficacy and effects of labeling equine umbilical cord blood (UCB)- and bone marrow (BM)-derived multipotent mesenchymal stromal cells (MSCs) with an ultrasmall superparamagnetic iron oxide (SPIO) contrast agent and the detection of labeled MSCs by use of MRI.

SAMPLE

UCB MSCs from placental tissues of 5 foals and BM MSCs from 5 horses.

PROCEDURES

UCB and BM MSC cultures were seeded in duplicate (5,000 cells/cm(2)). One duplicate was incubated with SPIO (50 μg/mL); the other was processed identically, but without SPIO. Mesenchymal stromal cells were expanded in triplicates for 5 passages and assessed for viability and proliferative capacity, labeling efficacy, and labeled cell proportion. For MRI detection, 5 × 10(6) labeled BM MSCs from passage 1 or 2 were injected into a collagenase-induced superficial digital flexor tendon defect of an equine cadaveric forelimb from 2 horses.

RESULTS

For passages 1, 2, and 3, labeling efficacy and cell proportion for UCB MSCs (99.6% [range, 98.8% to 99.9%], 16.6% [range, 6.5% to 36.1%], and 1.0% [range, 0.4% to 2.8%], respectively) were significantly higher than for BM MSCs (99.2% [range, 97.8% to 99.7%], 4.5% [range, 1.6% to 11.8%], and 0.2% [range, 0.1% to 0.6%], respectively). Labeling was not detectable after passage 3. Viability of MSCs was not affected, but cell doubling time increased in labeled MSCs, compared with that of unlabeled MSCs. On MRI 3-D T2*-weighted fast gradient echo sequences, decreased signal intensity was observed for BM passage 1 MSCs.

CONCLUSIONS AND CLINICAL RELEVANCE

Equine UCB and BM MSCs were labeled with SPIO at high efficiencies.

In vivo tracking of neuronal-like cells by magnetic resonance in rabbit models of spinal cord injury

In vitro experiments have demonstrated that neuronal-like cells derived from bone marrow mesenchymal stem cells can survive, migrate, integrate and help to restore the function and behaviors of spinal cord injury models, and that they may serve as a suitable approach to treating spinal cord injury. However, it is very difficult to track transplanted cells in vivo. In this study, we injected superparamagnetic iron oxide-labeled neuronal-like cells into the subarachnoid space in a rabbit model of spinal cord injury. At 7 days after cell transplantation, a small number of dot-shaped low signal intensity shadows were observed in the spinal cord injury region, and at 14 days, the number of these shadows increased on T2-weighted imaging. Perl's Prussian blue staining detected dot-shaped low signal intensity shadows in the spinal cord injury region, indicative of superparamagnetic iron oxide nanoparticle-labeled cells. These findings suggest that transplanted neuronal-like cells derived from bone marrow mesenchymal stem cells can migrate to the spinal cord injury region and can be tracked by magnetic resonance in vivo. Magnetic resonance imaging represents an efficient noninvasive technique for visually tracking transplanted cells in vivo.

Umbilical cord mesenchymal stem cells labeled with multimodal iron oxide nanoparticles with fluorescent and magnetic properties: application for in vivo cell tracking

Here we describe multimodal iron oxide nanoparticles conjugated to Rhodamine-B (MION-Rh), their stability in culture medium, and subsequent validation of an in vitro protocol to label mesenchymal stem cells from umbilical cord blood (UC-MSC) with MION-Rh. These cells showed robust labeling in vitro without impairment of their functional properties, the viability of which were evaluated by proliferation kinetic and ultrastructural analyzes. Thus, labeled cells were infused into striatum of adult male rats of animal model that mimic late onset of Parkinson’s disease and, after 15 days, it was observed that cells migrated along the medial forebrain bundle to the substantia nigra as hypointense spots in T2 magnetic resonance imaging. These data were supported by short-term magnetic resonance imaging. Studies were performed in vivo, which showed that about 5 × 10⁵ cells could be efficiently detected in the short term following infusion. Our results indicate that these labeled cells can be efficiently tracked in a neurodegenerative disease model.

Comparative Labeling of Equine and Ovine Multipotent Stromal Cells With Superparamagnetic Iron Oxide Particles for Magnetic Resonance Imaging In Vitro

The purpose of this study was to evaluate the use of three different superparamagnetic iron oxide (SPIO) particles for labeling of ovine and equine bone marrow (BM)-derived multipotent stromal cells (MSCs) in vitro. MSCs were obtained from five adult sheep and horses, respectively. After three passages (p3), cells were labeled with either 1) Molday ION Rhodamine B, 2) Endorem, 3) Resovist, or 4) remained unlabeled as control. Labeling efficiency, marker retention, and long-term detectability in MRI until p7 were evaluated. Further, proliferation capacity and trilineage differentiation as indicators for potential impact on stromal cell characteristics were assessed. MSCs of both species were successfully labeled with all three SPIO products. A high, exclusively intracellular, iron uptake was achieved by Molday ION Rhodamine B only. Labeling with Resovist led to prominent extracellular iron presence; labeling with Endorem was less efficient. During MRI, all labeled cells showed strong hypointense signals, contrary to unlabeled controls. Resovist induced the largest areas of hypointense signals, followed by Molday ION Rhodamine B and Endorem. MRI signal detectability decreased from p4 to p7. Proliferation, adipogenic, and osteogenic differentiation potential were not reduced by cell labeling compared to unlabeled cells. Chondrogenic differentiation capacity decreased with increasing amount of iron associated with the cells. Among the three products, Resovist and Molday were identified as promising labeling agents. While Resovist achieved superior results in most of the assessed parameters, Molday ION Rhodamine B ensured intracellular iron uptake without extracellular SPIO complexes and consistent hypointense signals on MRI.

Human neural progenitor cells retain viability, phenotype, proliferation, and lineage differentiation when labeled with a novel iron oxide nanoparticle, Molday ION Rhodamine B

Ultrasmall superparamagnetic iron-oxide particles (USPIOs) loaded into stem cells have been suggested as a way to track stem cell transplantation with magnetic resonance imaging, but the labeling, and post-labeling proliferation, viability, differentiation, and retention of USPIOs within the stem cells have yet to be determined for each type of stem cell and for each type of USPIO. Molday ION Rhodamine B™ (BioPAL, Worcester, MA, USA) (MIRB) has been shown to be a USPIO labeling agent for mesenchymal stem cells, glial progenitor cells, and stem cell lines. In this study, we have evaluated MIRB labeling in human neuroprogenitor cells and found that human neuroprogenitor cells are effectively labeled with MIRB without use of transfection reagents. Viability, proliferation, and differentiation properties are unchanged between MIRB-labeled neuroprogenitors cells and unlabeled cells. Moreover, MIRB-labeled human neuroprogenitor cells can be frozen, thawed, and replated without loss of MIRB or even without loss of their intrinsic biology. Overall, those results show that MIRB has advantageous properties that can be used for cell-based therapy.

Assessment of biological characteristics of adipose tissue-derived stem cells co-labeled with Molday ION Rhodamine B™ and green fluorescent protein in vitro

The current study aimed to investigate adipose tissue-derived stem cells (ADSCs) in vivo by multimodality imaging following implantation for cellular therapy. The biological characteristics of ADSCs co-labeled with Molday ION Rhodamine B™ (MIRB) and green fluorescent protein (GFP) were studied in vitro. Following rat ADSC isolation and culture, a combined labeling strategy for ADSCs based on genetic modification of the reporter gene GFP with lentiviral vector expression enhancement and physical MIRB labeling was performed. Cell viability, proliferation, membrane-bound antigens and multiple differentiation ability were compared between the labeled and unlabeled ADSCs. The ADSCs were successfully labeled with GFP and MIRB, showing various fluorescent colors for marker identification. The fluorescence emitted by the GFP protein was sustained and exhibited stable expression, while MIRB fluorescence decreased with time. Compared with the unlabeled ADSCs, no significant differences were detected in cell viability, proliferation, membrane-bound antigens and multiple differentiation ability in the co-labeled samples (P>0.05). No significant effects on the biophysical properties of ADSCs were observed following co-labeling with lentiviral vectors encoding the gene for emerald green fluorescent protein and MIRB. The ADSCs were able to be efficiently tracked in vitro and in vivo by multimodality imaging thus, the co-labeling approach provides a novel strategy for therapeutic gene studies.