Department of Neuroscience
Laboratory of Tissue Culture and Stem Cells
Research topics
- Characterization of adult and embryonic stem cells in vitro;
- development of nanoparticles for cell labeling suitable for in vivo cell tracking;
- cultivation and differentiation of human embryonic stem cells into a neuronal phenotype;
- phenotyping of stem cells by means of flow cytometry;
- regeneration and repair of stroke lesions using human embryonic stem cells;
- regeneration and repair of injured spinal cord using stem cells and biomaterials;
- analysis of the growth factors and cytokines released from injured and tumor tissue and their role in the homing of MSCs to the lesions;
- cell-polymer constructs designed to bridge lesions of the central nervous tissue;
- nanofiber scaffolds for two- and three-dimensional cell cultivation.
Regeneration of brain and spinal cord injury using stem cells
Injury of the adult CNS, such as spinal cord trauma or stroke, invariably results in the loss of neurons and the loss of axonal processes involved in the lesion. This often results in severe functional impairment, due to the formation of complex scar tissue within the cavity as the result of cell death, inflammation and tissue degradation. Stem and progenitor cells from various sources are currently being investigated for their potential to treat CNS injury and numerous neurodegenerative diseases. Transplanted stem cells can either REPAIR damaged tissue by replacing missing populations of cells or RESCUE cells in the injured brain or spinal cord by the production of cytokines (interleukins) and/or neurotrophic factors that facilitate regeneration and/or revascularization.
MSCs labeled with nanoparticles implanted into rats with a spinal cord compression lesion.
(A) Prussian blue staining of a spinal cord compression lesion. Only a few weakly stained Prussian blue-positive cells are found in the area of a spinal cord lesion without cell implantation.
(B) Prussian blue staining of a spinal cord lesion with intravenously injected nanoparticle-labeled MSCs. The lesion is populated with
Prussian blue-positive cells. Note the smaller lesion size in implanted animals than in controls
In our projects we study adult stem cells (isolated from bone marrow, peripheral blood or fat tissue) as well as human embryonic stem cells and immortalized fetal spinal cord cells for the treatment of stroke and spinal cord injury. We use photochemical lesion and middle cerebral artery occlusion (MCAO) models to investigate stroke, while hemisection and balloon-induced compression lesions are employed as acute and chronic models of spinal cord injury, respectively. We evaluate the rescue as well as the repair effect of the cells used in the treatment by means of behavioral tests, histology and immunohistochemistry.
Cell labeling
For the success of cell therapy it is important to monitor the fate of transplanted cells in vivo. One such approach involves the use of superparamagnetic iron oxide nanoparticles as labels for cell tracking.
Labeling of stem cells with iron-oxide nanoparticles.
(A) A cell labeled with iron-oxide nanoparticles undergoing cell division (staining for BrdU), confirming that the incorporation of nanoparticles does not adversely affect cell viability.
(B) T-2 weighted image of a cortical photochemical lesion and mouse embryonic stem cells implanted into the contralateral hemisphere two weeks after implantation. The cell implant in the hemisphere contralateral to the lesion as well as the lesion itself are visible as hypointense areas.
(C) A hypointense signal in the lesion observed thirty days after the intravenous injection of MSCs labeled with nanoparticles.
In collaboration with the Institute of Macromolecular Chemistry ASCR, we have developed and patented several types of iron oxide nanoparticles with modified coatings that can be used for cell labeling and in vivo tracking by MR imaging. Cells labeled with these nanoparticles exhibit better viability and improved labeling efficiency in combination with a lower concentration of iron within the cells when compared with commercial contrast agents, such as Endorem, (Guerbet, France).
Cell migration
Though mesenchymal stem cells (MSCs) have a positive effect on functional outcome after spinal cord injury (SCI), it is still not clear what is the mechanism of action of MSCs in the lesion, what mechanisms are involved in attracting the MSCs into the site of SCI and why the cells migrate towards the lesion. Therefore, we study the mechanisms underlying the migration and engraftment of MSCs into a spinal cord injury from the point of view of chemotactic migration and cytokine expression. In collaboration with the University of Bergen, we also investigate the ability of MSCs to migrate to tumor tissue and the possibilities for their use in anti-cancer therapy.
