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

SummaryBackgroundTissue 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.ObjectiveThe purpose of this study was to assess the effect of SPIO labelling on adult human chondrocyte behaviour.MethodsCells 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.ResultsSPIO 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.ConclusionsThis paper demonstrates for the first time the effects of SPIO labelling on chondrocyte behaviour, illustrating its potential for in vivo tracking of implanted chondrocytes

Grand Challenges in global eye health: a global prioritisation process using Delphi method

Background We undertook a Grand Challenges in Global Eye Health prioritisation exercise to identify the key issues that must be addressed to improve eye health in the context of an ageing population, to eliminate persistent inequities in health-care access, and to mitigate widespread resource limitations. Methods Drawing on methods used in previous Grand Challenges studies, we used a multi-step recruitment strategy to assemble a diverse panel of individuals from a range of disciplines relevant to global eye health from all regions globally to participate in a three-round, online, Delphi-like, prioritisation process to nominate and rank challenges in global eye health. Through this process, we developed both global and regional priority lists. Findings Between Sept 1 and Dec 12, 2019, 470 individuals complete round 1 of the process, of whom 336 completed all three rounds (round 2 between Feb 26 and March 18, 2020, and round 3 between April 2 and April 25, 2020) 156 (46%) of 336 were women, 180 (54%) were men. The proportion of participants who worked in each region ranged from 104 (31%) in sub-Saharan Africa to 21 (6%) in central Europe, eastern Europe, and in central Asia. Of 85 unique challenges identified after round 1, 16 challenges were prioritised at the global level; six focused on detection and treatment of conditions (cataract, refractive error, glaucoma, diabetic retinopathy, services for children and screening for early detection), two focused on addressing shortages in human resource capacity, five on other health service and policy factors (including strengthening policies, integration, health information systems, and budget allocation), and three on improving access to care and promoting equity. Interpretation This list of Grand Challenges serves as a starting point for immediate action by funders to guide investment in research and innovation in eye health. It challenges researchers, clinicians, and policy makers to build collaborations to address specific challenge

In vivo imaging of cartilage degeneration using mu CT-arthrography

Objective: In vivo imaging of cartilage degeneration in small animal models is nowadays practically impossible. In the present study, we investigated the use of micro-computed tomography (mu CT) in combination with a negatively charged ionic iodine dimer (ioxaglate) for in vivo assessment of cartilage degeneration in a small animal model. Methods: Cartilage degeneration was induced in the right knee of rats by injection of mono-iodoacetate (MIA). We imaged the rat knees with ioxaglate enhanced mu CT-arthrography at 4, 16 and 44 days after MIA injection. Subsequently, mu CT-arthrographic findings were evaluated and compared with quantitative histology of the patellar cartilage. Results: In vivo mu CT-arthrography clearly detected cartilage degeneration in the rat knee-joints, in which the ioxaglate diffused into the degenerated cartilage layer. Higher mu CT-attenuation values and smaller total volumes of the cartilage layer were detected at longer time periods after MIA injection, which is quantitatively confirmed by histology. Conclusion: In vivo mu CT-arthrography is a valuable tool for detection of minor cartilage alterations and distinguishes different stages of cartilage degeneration in a small animal model. Since mu CT, at the same time, also visualizes osteophyte formation and changes in the underlying subchondral bone structures, the technique will be very useful for longitudinal overall assessment of the development of (osteo)arthritis and to study interventions in small animal models. (C) 2008 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved

Adult Human Bone Marrow- and Adipose Tissue-Derived Stromal Cells Support the Formation of Prevascular-like Structures from Endothelial Cells In Vitro

Inadequate vascularization of in vitro-engineered tissue constructs after implantation is a major problem in most tissue-engineering applications. In this study we evaluated whether adipose tissue-derived stromal cells (ASCs), similar to bone marrow-derived stromal cells (BMSCs), can support the organization of endothelial cells into prevascular-like structures using an in vitro model. In addition, we investigated the mechanisms leading to the support of endothelial organization by these cells. We cultured human umbilical vein endothelial cells (HUVECs), ASCs, and BMSCs either alone or in combination in fibrin-embedded spheroids for 14 days. We found that BMSCs and ASCs formed cellular networks that expressed a smooth muscle actin and, in the case of ASCs, also CD34. Further, BMSCs and ASCs secreted hepatocyte growth factor and tissue inhibitor of metalloproteinase 1 and 2. In addition, ASC-conditioned medium induced HUVEC outgrowth, whereas BMSC-conditioned medium and hepatocyte growth factor-supplemented medium did not. Finally, both BMSCs and ASCs supported HUVEC organization into prevascular-like structures when cocultured. Our results suggest that both BMSCs and ASCs can support the formation of prevascular-like structures in vitro. Further, our findings indicate that cell-cell contacts and reciprocal signaling play an important role in the formation of these prevascular structures

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

Effects of iron oxide incorporation for long term cell tracking on MSC differentiation in vitro and in vivo

Successful cell therapy will depend on the ability to monitor transplanted cells. With cell labeling, it is important to demonstrate efficient long term labeling without deleterious effects on cell phenotype and differentiation capacity. We demonstrate long term (7 weeks) retention of superparamagnetic iron oxide particles (SPIO) by mesenchymal stem cells (MSCs) in vivo, detectable by MRI. In vitro, multilineage differentiation (osteogenic, chondrogenic and adipogenic) was demonstrated by histological evaluation and molecular analysis in SPIO labeled and unlabeled cells. Gene expression levels were comaparable to unlabeled controls in adipogenic and chondrogenic conditions however not in the osteogenic condition. MSCs seeded into a scaffold for 21 days and implanted subcutaneously into nude mice for 4 weeks, showed profoundly altered phenotypes in SPIO labeled samples compared to implanted unlabeled control scaffolds, indicating chondrogenic differentiation. This study demonstrates long term MSC traceability using SPIO and MRI, uninhibited multilineage MSC differentiation following SPIO labeling, though with subtle but significant phenotypical alterations. (C) 2008 Elsevier Inc. All rights reserved