| 1. |
- Frost, Hanna, et al.
(författare)
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Electrospun nerve guide conduits have the potential to bridge peripheral nerve injuries in vivo.
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:Article number: 16716
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Tidskriftsartikel (refereegranskat)abstract
- Electrospinning can be used to mimic the architecture of an acellular nerve graft, combining microfibers for guidance, and pores for cellular infiltration. We made electrospun nerve guides, from polycaprolactone (PCL) or poly-L-lactic acid (PLLA), with aligned fibers along the insides of the channels and random fibers around them. We bridged a 10 mm rat sciatic nerve defect with the guides, and, in selected groups, added a cell transplant derived from autologous stromal vascular fraction (SVF). For control, we compared to hollow silicone tubes; or autologous nerve grafts. PCL nerve guides had a high degree of autotomy (8/43 rats), a negative indicator with respect to future usefulness, while PLLA supported axonal regeneration, but did not outperform autologous nerve grafts. Transplanted cells survived in the PLLA nerve guides, but axonal regeneration was not enhanced as compared to nerve guides alone. The inflammatory response was partially enhanced by the transplanted cells in PLLA nerve grafts; Schwann cells were poorly distributed compared to nerve guide without cells. Tailor-made electrospun nerve guides support axonal regeneration in vivo, and can act as vehicles for co-transplanted cells. Our results motivate further studies exploring novel nerve guides and the effect of stromal cell-derived factors on nerve generation.
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| 2. |
- Zalis, Marina Castro, et al.
(författare)
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Exploration of physical and chemical cues on retinal cell fate
- 2016
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Ingår i: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431 .- 1095-9327. ; 75, s. 122-132
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Tidskriftsartikel (refereegranskat)abstract
- Identification of the key components in the physical and chemical milieu directing donor cells into a desired phenotype is a requirement in the investigation of bioscaffolds for the advancement of cell-based therapies for retinal neurodegeneration. We explore the effect of electrospun poly-ε-caprolactone (PCL) fiber scaffold topography and functionalization and culture medium, on the behavior of mouse retinal cells. Dissociated mouse retinal post-natal cells were seeded on random or aligned oriented fibers, with or without laminin coating and cultured with either basic or neurotrophins enriched medium for 7 days. Addition of laminin in combination with neurotrophins clearly promoted cell– morphology, fate, and neurite extension. Nanotopography per se significantly affected cell morphology, with mainly bipolar profiles on aligned fibers and more multipolar profiles on random fibers. Laminin induced a remarkable 90° switch of neurite orientation. Herewith, we demonstrate that the chemical cue is stronger than the physical cue for the orientation of retinal neurites and describe the requirement of both neurotrophins and extracellular matrix proteins for extended neurite outgrowth and formation of complex retinal neuronal networks. Therefore, tailor-made PCL fiber mats, which can be physically and chemically modified, indeed influence cell behavior and hence motivate further retinal restorative studies using this system.
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| 3. |
- Bauer, Patrik Maximilian, et al.
(författare)
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Inflamed In Vitro Retina : Cytotoxic Neuroinflammation and Galectin-3 Expression
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:9
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Tidskriftsartikel (refereegranskat)abstract
- Background Disease progression in retinal neurodegeneration is strongly correlated to immune cell activation, which may have either a neuroprotective or neurotoxic effect. Increased knowledge about the immune response profile and retinal neurodegeneration may lead to candidate targets for treatments. Therefore, we have used the explanted retina as a model to explore the immune response and expression of the immune modulator galectin-3 (Gal-3), induced by the cultivation per se and after additional immune stimulation with lipopolysaccharide (LPS), and how this correlates with retinal neurotoxicity. Methods Post-natal mouse retinas were cultured in a defined medium. One group was stimulated with LPS (100 ng/ml, 24 h). Retinal architecture, apoptotic cell death, and micro- and macroglial activity were studied at the time of cultivation (0 days in vitro (DIV)) and at 3, 4 and 7 DIV using morphological staining, biochemical- and immunohistochemical techniques. Results Our results show that sustained activation of macro- and microglia, characterized by no detectable cytokine release and limited expression of Gal-3, is not furtherinducing apoptosis additional to the axotomy-induced apoptosis in innermost nuclear layer. An elevated immune response was detected after LPS stimulation, as demonstrated primarily by release of immune mediators (i.e. interleukin 2 (IL-2), IL-6, KC/GRO (also known as CLCX1) and tumour necrosis factor-α (TNF-α)), increased numbers of microglia displaying morphologies of late activation stages as well as Gal-3 expression. This was accompanied with increased apoptosis in the two additional nuclear layers, and damage to retinal gross architecture. Conclusion We demonstrate that an immune response characterized by sustained and increased release of cytokines, along with an increase in Gal-3 expression, is accompanied by significant increased neurotoxicity in the explanted retina. Further investigations using the current setting may lead to increased understanding on the mechanisms involved in neuronal loss in retinal neurodegenerations. © 2016 Bauer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 4. |
- Dahlin, Lars B., et al.
(författare)
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Traumatic Peripheral Nerve Injuries : Experimental Models for Repair and Reconstruction
- 2019
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Ingår i: Animal Models of Neurotrauma. - New York, NY : Springer New York. - 0893-2336 .- 1940-6045. - 9781493997114 - 9781493997091 ; 149, s. 169-186
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Bokkapitel (refereegranskat)abstract
- Peripheral nerve injuries are difficult to treat, and the clinical outcome after surgical repair and reconstruction is still insufficient, particularly concerning recovery of sensory function. To improve the clinical treatment strategies, experimental models are used to systematically examine the mechanisms behind nerve regeneration and assess the improvement of nerve regeneration by introduction of new surgical nerve repair and reconstruction methods (e.g., novel devices made by bioartificial materials). Rat models, where the sciatic nerve has essentially a similar size as a human digital nerve, are widely used to evaluate nerve regeneration with the inherent advantages and disadvantages of the experimental models. Estimations revealing that a large number of diabetic patients will eventually suffer from peripheral nerve injury have motivated development of suitable experimental diabetes models for studying the nerve regeneration process and novel treatment approaches. We have successfully used the Goto-Kakizaki rat model, which shows moderately increased blood sugar closely resembling type 2 diabetes, for assessing the surgical peripheral nerve regeneration potential with and without artificial scaffolds. In order to improve outcome after repair and reconstruction of nerve injuries, one has to have a clear concept concerning how to evaluate novel repair and reconstruction techniques in experimental models before clinical studies can be initiated in an accurate way.
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| 5. |
- Englund Johansson, Ulrica, et al.
(författare)
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Human neural progenitor cells promote photoreceptor survival in retinal explants
- 2010
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835 .- 1096-0007. ; 90:2, s. 292-299
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Tidskriftsartikel (refereegranskat)abstract
- Different types of progenitor and stem cells have been shown to provide neuroprotection in animal models of photoreceptor degeneration. The present study was conducted to investigate whether human neural progenitor cells (HNPCs) have neuroprotective properties on retinal explants models with calpain- and caspase-3-dependent photoreceptor cell death. In the first experiments, HNPCs in a feeder layer were co-cultured for 6 days either with postnatal rd1 mouse or normal rat retinas. Retinal histological sections were used to determine outer nuclear layer (ONL) thickness, and to detect the number of photoreceptors with labeling for calpain activity, cleaved caspase-3 and TUNEL The ONL thickness of co-cultured rat and rd1 retinas was found to be almost 10% and 40% thicker, respectively, compared to controls. Cell counts of calpain activity, cleaved caspase-3 and TUNEL labeled photoreceptors in both models revealed a 30-50% decrease when co-cultured with HNPCs. The results represent significant increases of photoreceptor survival in the co-cultured retinas. In the second experiments, for an identification of putative survival factors, or a combination of them, a growth factor profile was performed on conditioned medium. The relative levels of various growth factors were analyzed by densitometric measurements of growth factor array membranes. Following growth factors were identified as most potential survival factors: granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GMCSF), insulin-like growth factor 11 (IGF-II), neurotrophic factor 3 (NT-3), placental growth factor (PIGF), transforming growth factors (TGF-beta 1 and TGF-beta 2) and vascular endothelial growth factor (VEGF-D). HNPCs protect both against calpain- and caspase-3-dependent photoreceptor cell death in the rd1 mouse and against caspase-3-dependent photoreceptor cell death in normal rat retinas in vitro. The protective effect is possibly achieved by a variety of growth factors secreted from the HNPCs. (C) 2009 Elsevier Ltd. All rights reserved.
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| 6. |
- Englund Johansson, Ulrica, et al.
(författare)
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Tailor-Made Electrospun Culture Scaffolds Control Human Neural Progenitor Cell Behavior : Studies on Cellular Migration and Phenotypic Differentiation
- 2017
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Ingår i: Journal of Biomaterials and Nanobiotechnology. - : Scientific Research Publishing. - 2158-7027 .- 2158-7043. ; 8:1, s. 1-21
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Tidskriftsartikel (refereegranskat)abstract
- In neuroscience research, cell culture systems are essential experimental platforms. It is of great interest to explore in vivo-like culture substrates. We explored how basic properties of neural cells, nuclei polarization, phenotypic differentiation and distribution/migration, were affected by the culture at poly-L-lactic acid (PLLA) fibrous scaffolds, using a multipotent mitogen-expanded human neural progenitor cell (HNPC) line. HNPCs were seeded, at four different surfaces: two different electrospun PLLA (d = 1.2 - 1.3 μm) substrates (parallel or random aligned fibers), and planar PLL- and PLLA surfaces. Nuclei analysis demonstrated a non-directed cellular migration at planar surfaces and random fibers, different from cultures at aligned fibers where HNPCs were oriented parallel with the fibers. At aligned fibers, HNPCs displayed the same capacity for phenotypic differentiation as after culture on the planar surfaces. However, at random fibers, HNPCs showed a significant lower level of phenotypic differentiation compared with cultures at the planar surfaces. A clear trend towards greater neuronal formation at aligned fibers, compared to cultures at random fibers, was noted. We demonstrated that the topography of in vivo-resembling PLLA scaffolds significantly influences HNPC behavior, proven by different migration behavior, phenotypic differentiation potential and nuclei polarization. This knowledge is useful in future exploration of in vivo-resembling neural cell system using electrospun scaffolds.
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| 7. |
- Gunnarsson, Stefán B., et al.
(författare)
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Analysis of complexes formed by small gold nanoparticles in low concentration in cell culture media
- 2019
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:6
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Tidskriftsartikel (refereegranskat)abstract
- New nanomaterials are constantly developed with applications in everything from cosmetics to high tech electronics. Assessing their biological impact has been done by analysis of their adsorbed protein corona, in vitro cell assays, and larger scale ecotoxicological studies. This has proved to be a huge challenge due to the wide range of available nanomaterials and their unpredictable behaviour in different environments. Furthermore, the enormous number of experimental variables make comparisons difficult. Concentration is one of these variables and can vary greatly depending on the aim of the study. When analysing the protein corona, concentrations are often higher than in cell assays. Using a combination of complementary techniques, we have characterised 20 nm gold nanoparticles in a concentration level commonly used in cell studies. We compare their behaviour in a commonly used, protein rich medium and one protein poor medium over 24 hours. Under these conditions, the NPs were stable in protein rich environment but underwent gradual aggregation in protein poor medium. We characterise the biomolecular corona in both media. In protein poor medium, we can describe the often overlooked aggregation. The aggregates' morphology is confirmed by cryo-TEM. Finally, in the protein poor medium, by infrared spectroscopy, we have identified the amino acid arginine in the biomolecular corona which drives the aggregation.
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| 8. |
- Hörberg, Carl Johan, et al.
(författare)
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Spontaneous Cell Cluster Formation in Human iPSC-Derived Neuronal Spheroid Networks Influences Network Activity
- 2022
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Ingår i: eNeuro. - 2373-2822. ; 9:5, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional neuronal culture systems such as spheroids, organoids, and assembloids constitute a branch of neuronal tissue engineering that has improved our ability to model the human brain in the laboratory. However, the more elaborate the brain model, the more difficult it becomes to study functional properties such as electrical activity at the neuronal level, similar to the challenges of studying neurophysiology in vivo. We describe a simple approach to generate self-assembled three-dimensional neuronal spheroid networks with defined human cell composition on microelectrode arrays. Such spheroid networks develop a highly three-dimensional morphology with cell clusters up to 60 μm in thickness and are interconnected by pro-nounced bundles of neuronal fibers and glial processes. We could reliably record from up to hundreds of neurons simultaneously per culture for ≤90 d. By quantifying the formation of these three-dimensional structures over time, while regularly monitoring electrical activity, we were able to establish a strong link between spheroid morphology and network activity. In particular, the formation of cell clusters accelerates formation and maturation of correlated network activity. Astrocytes both influence electrophysiological network activity as well as accelerate the transition from single cell layers to cluster formation. Higher concentrations of astrocytes also have a strong effect of modulating synchronized network activity. This approach thus represents a practi-cal alternative to often complex and heterogeneous organoids, providing easy access to activity within a brain-like 3D environment.
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| 9. |
- Hörberg, Carl-Johan, et al.
(författare)
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Spontaneous Cell Cluster Formation in Human iPSC-Derived Neuronal Spheroid Networks Influences Network Activity
- 2022
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Ingår i: eNeuro. - : Society for Neuroscience. - 2373-2822. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional neuronal culture systems such as spheroids, organoids, and assembloids constitute a branch of neuronal tissue engineering that has improved our ability to model the human brain in the laboratory. However, the more elaborate the brain model, the more difficult it becomes to study functional properties such as electrical activity at the neuronal level, similar to the challenges of studying neurophysiology in vivo. We describe a simple approach to generate self-assembled three-dimensional neuronal spheroid networks with defined human cell composition on microelectrode arrays. Such spheroid networks develop a highly three-dimensional morphology with cell clusters up to 60 μm in thickness and are interconnected by pronounced bundles of neuronal fibers and glial processes. We could reliably record from up to hundreds of neurons simultaneously per culture for ≤90 d. By quantifying the formation of these three-dimensional structures over time, while regularly monitoring electrical activity, we were able to establish a strong link between spheroid morphology and network activity. In particular, the formation of cell clusters accelerates formation and maturation of correlated network activity. Astrocytes both influence electrophysiological network activity as well as accelerate the transition from single cell layers to cluster formation. Higher concentrations of astrocytes also have a strong effect of modulating synchronized network activity. This approach thus represents a practical alternative to often complex and heterogeneous organoids, providing easy access to activity within a brain-like 3D environment.
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| 10. |
- Jakobsson, Albin, et al.
(författare)
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Three-dimensional functional human neuronal networks in uncompressed low-density electrospun fiber scaffolds
- 2017
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Ingår i: Nanomedicine. - : Elsevier. - 1549-9634 .- 1549-9642. ; 13:4, s. 1563-1573
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate an artificial three-dimensional (3D) electrical active human neuronal network system, by the growth of brain neural progenitors in highly porous low density electrospun poly-ε-caprolactone (PCL) fiber scaffolds. In neuroscience research cell-based assays are important experimental instruments for studying neuronal function in health and disease. Traditional cell culture at 2D-surfaces induces abnormal cell–cell contacts and network formation. Hence, there is a tremendous need to explore in vivo-resembling 3D neural cell culture approaches. We present an improved electrospinning method for fabrication of scaffolds that promote neuronal differentiation into highly 3D integrated networks, formation of inhibitory and excitatory synapses and extensive neurite growth. Notably, in 3D scaffolds in vivo-resembling intermixed neuronal and glial cell network were formed, whereas in parallel 2D cultures a neuronal cell layer grew separated from an underlying glial cell layer. Hence, the use of the 3D cell assay presented will most likely provide more physiological relevant results.
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