| 1. |
- Ahl, Matilda, et al.
(författare)
-
Immune response in the eye following epileptic seizures
- 2016
-
Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Epileptic seizures are associated with an immune response in the brain. However, it is not known whether it can extend to remote areas of the brain, such as the eyes. Hence, we investigated whether epileptic seizures induce inflammation in the retina. Methods: Adult rats underwent electrically induced temporal status epilepticus, and the eyes were studied 6 h, 1, and 7 weeks later with biochemical and immunohistochemical analyses. An additional group of animals received CX3CR1 antibody intracerebroventricularly for 6 weeks after status epilepticus. Results: Biochemical analyses and immunohistochemistry revealed no increased cell death and unaltered expression of several immune-related cytokines and chemokines as well as no microglial activation, 6 h post-status epilepticus compared to non-stimulated controls. At 1 week, again, retinal cytoarchitecture appeared normal and there was no cell death or micro- or macroglial reaction, apart from a small decrease in interleukin-10. However, at 7 weeks, even if the cytoarchitecture remained normal and no ongoing cell death was detected, the numbers of microglia were increased ipsi- and contralateral to the epileptic focus. The microglia remained within the synaptic layers but often in clusters and with more processes extending into the outer nuclear layer. Morphological analyses revealed a decrease in surveying and an increase in activated microglia. In addition, increased levels of the chemokine KC/GRO and cytokine interleukin-1β were found. Furthermore, macroglial activation was noted in the inner retina. No alterations in numbers of phagocytic cells, infiltrating macrophages, or vascular pericytes were observed. Post-synaptic density-95 cluster intensity was reduced in the outer nuclear layer, reflecting seizure-induced synaptic changes without disrupted cytoarchitecture in areas with increased microglial activation. The retinal gliosis was decreased by a CX3CR1 immune modulation known to reduce gliosis within epileptic foci, suggesting a common immunological reaction. Conclusions: Our results are the first evidence that epileptic seizures induce an immune response in the retina. It has a potential to become a novel non-invasive tool for detecting brain inflammation through the eyes.
|
|
| 2. |
- Ahl, Matilda, et al.
(författare)
-
Inflammatory reaction in the retina after focal non-convulsive status epilepticus in mice investigated with high resolution magnetic resonance and diffusion tensor imaging
- 2021
-
Ingår i: Epilepsy Research. - : Elsevier. - 0920-1211 .- 1872-6844. ; 176
-
Tidskriftsartikel (refereegranskat)abstract
- Pathophysiological consequences of focal non-convulsive status epilepticus (fNCSE) have been difficult to demonstrate in humans. In rats fNCSE pathology has been identified in the eyes. Here we evaluated the use of high-resolution 7 T structural T1-weighted magnetic resonance imaging (MRI) and 9.4 T diffusion tensor imaging (DTI) for detecting hippocampal fNCSE-induced retinal pathology ex vivo in mice. Seven weeks post-fNCSE, increased number of Iba1+ microglia were evident in the retina ipsilateral to the hemisphere with fNCSE, and morphologically more activated microglia were found in both ipsi- and contralateral retina compared to non-stimulated control mice. T1-weighted intensity measurements of the contralateral retina showed a minor increase within the outer nuclear and plexiform layers of the lateral retina. T1-weighted measurements were not performed in the ipsilateral retina due to technical difficulties. DTI fractional anisotropy(FA) values were discretely altered in the lateral part of the ipsilateral retina and unaltered in the contralateral retina. No changes were observed in the distal part of the optic nerve. The sensitivity of both imaging techniques for identifying larger retinal alteration was confirmed ex vivo in retinitis pigmentosa mice where a substantial neurodegeneration of the outer retinal layers is evident. With MR imaging a 50 % decrease in DTI FA values and significantly thinner retina in T1-weighted images were detected. We conclude that retinal pathology after fNCSE in mice is subtle and present bilaterally. High-resolution T1-weighted MRI and DTI independently did not detect the entire pathological retinal changes after fNCSE, but the combination of the two techniques indicated minor patchy structural changes.
|
|
| 3. |
- Bauer, Patrik Maximilian, et al.
(författare)
-
Inflamed In Vitro Retina : Cytotoxic Neuroinflammation and Galectin-3 Expression
- 2016
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:9
-
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.
|
|
| 4. |
- Blixt Wojciechowski, Anita, et al.
(författare)
-
Long-term survival and glial differentiation of the brain-derived precursor cell line RN33B after subretinal transplantation to adult normal rats
- 2002
-
Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 20:2, s. 163-173
-
Tidskriftsartikel (refereegranskat)abstract
- The potential use of in vitro-expanded precursor cells or cell lines in repair includes transplantation of such cells for cell replacement purposes and the activation of host cells to provide "self-repair." Recently, we have reported that cells from the brain-derived cell line RN33B (derived from the embryonic rat medullary raphe and immortalized through retroviral transduction of the temperature-sensitive mutant of the simian virus 40 ([SV40] large T-antigen) survive for at least 4 weeks, integrate, and differentiate after subretinal grafting to normal adult rats. Here, we demonstrate that grafts of these cells survive for at least 4 months after subretinal transplantation to adult, normal immunosuppressed rats. Implanted cells integrate into the retinal pigment epithelium and the inner retinal layers, and the anterior part of the optic nerve. In addition, the RN33B cells migrate within the retina, occupying the whole retina from one eccentricity to the other. A large fraction of the grafted cells differentiate into glial cells, as shown by double labeling of the reporter genes LacZ or green fluorescent protein, and several glial markers, including oligodendrocytes. However, the cells did not differentiate into retinal neurons, judging from their lack of expression of retinal neuronal phenotypic markers. A significant number of the implanted cells in the host retina were in a proliferative stage, judging from proliferative cell nuclear antigen and SV40 large T-antigen immunohistochemistry. To conclude, the cells survived, integrated, and migrated over long distances within the host. Therefore, our results may be advantageous for future design of therapeutic strategies, since such cells may have the potential of being a source of, for example, growth factor delivery in experimental models of retinal degeneration.
|
|
| 5. |
|
|
| 6. |
- Blixt Wojciechowski, Anita, et al.
(författare)
-
Migratory capacity of the cell line RN33B and the host glial cell response after subretinal transplantation to normal adult rats
- 2004
-
Ingår i: Glia. - : John Wiley & Sons. - 0894-1491 .- 1098-1136. ; 47:1, s. 58-67
-
Tidskriftsartikel (refereegranskat)abstract
- As previously reported, the brain-derived precursor cell line RN33B has a great capacity to migrate when transplanted to adult brain or retina. This cell line is immortalized with the SV40 large T-antigen and carries the reporter gene LacZ and the green fluorescent protein GFP. In the present study, the precursor cells were transplanted to the subretinal space of adult rats and investigated early after grafting. The purpose was to demonstrate the migration of the grafted cells from the subretinal space into the retina and the glial cell response of the host retina. Detachment caused by the transplantation method was persistent up to 4 days after transplantation, and then reattachment occurred. The grafted cells were shown to migrate in between the photoreceptor cells before entering into the plexiform layers. Molecules involved in migration of immature neuronal cells as the polysialylated neural cell adhesion molecule (PSA-NCAM) and the collapsing response-mediated protein 4 (TUC-4) was found in the plexiform layers of the host retina, but not in the grafted cells. The expression of the intermediate filaments GFAP, vimentin, and nestin was intensely upregulated immediately after transplantation. A less pronounced upregulation was observed on sham-operated animals. In summary, the RN33B cell line migrated promptly posttransplantation and settled preferably into the plexiform layers of the retina, the same layers where the migration cues PSA-NCAM and TUC-4 were established. In addition, both the transplantation method per se and the implanted cells caused an intense glial cell response by the host retina.
|
|
| 7. |
- Blixt Wojciechowski, Anita, et al.
(författare)
-
Subretinal Transplantation of Brain-derived Precursor Cells to Young RCS Rats Promotes Photoreceptor Cell Survival☆
- 2002
-
Ingår i: Experimental Eye Research. - : Elsevier. - 0014-4835 .- 1096-0007. ; 75:1, s. 23-37
-
Tidskriftsartikel (refereegranskat)abstract
- The potential use of in vitro-expanded precursor cells or cell lines in brain repair includes transplantation of such cells for cell replacement purposes and the activation of host cells to provide 'self-repair'. Recently, it has been reported that the immortalized brain-derived cell line RN33B (derived from the embryonic rat medullary raphe) survive, integrate and differentiate after subretinal grafting to normal adult rats. Here, it is demonstrated that grafts of these cells survive for at least 6 weeks after implantation into postnatal days 21 and 35 retinas of normal and Royal College of Surgeons rats, a model of retinal degeneration. Implanted cells integrate into the retinal pigment epithelium and the inner retinal layers, and the anterior part of the optic nerve of both normal and Royal College of Surgeons rats. The RN33B cells migrate within the retina, occupying the whole retina from one eccentricity to the other. A significant number of the grafted cells differentiate into glial cells, as shown by the double labelling of the reporter genes LacZ or green fluorescent protein, with several glial markers, including oligodendrocytic markers. Many implanted cells in the host retina were in a proliferative stage judging from proliferative cell nuclear antigen and SV40 large T-antigen immunohistochemistry. Interestingly, there was a promotion of photoreceptor survival, extending over more than 2/3 of the superior hemisphere, in Royal College of Surgeons rats transplanted at postnatal day 21, but not at postnatal day 35. In addition, grafted cells were found in the surviving photoreceptor layer in these rats.
|
|
| 8. |
- Blixt Wojciechowski, Anita, et al.
(författare)
-
Survival and long distance migration of brain-derived precursor cells transplanted to adult rat retina
- 2004
-
Ingår i: Stem Cells. - : AlphaMed Press. - 1549-4918 .- 1066-5099. ; 22:1, s. 27-38
-
Tidskriftsartikel (refereegranskat)abstract
- Neural precursor cells transplanted to adult retina can integrate into the host. This is especially true when the neural precursor rat cell line RN33B is used. This cell line carries the reporter genes LacZ and green fluorescent protein (GFP). In grafted rat eyes, RN33B cells are localized from one eccentricity to the other of the host retina. In the present study, whole-mounted retinas were analyzed to obtain a more appropriate evaluation of the amount of transgene-expressing cells and the migratory capacity of these cells 3 and 8 weeks post-transplantation. Quantification was made of the number of beta-galactosidase- and GFP-expressing cells with a semiautomatized stereological cell counting system. With the same system, delineation of the distribution area of the grafted cells was also performed. At 3 weeks, 68% of the grafted eyes contained marker-expressing cells, whereas at 8 weeks only 35% of the eyes contained such cells. Counting of marker-expressing cells demonstrated a lower number of transgene-expressing cells at 3 weeks compared with 8 weeks post-transplantation. The distribution pattern of marker gene-expressing cells revealed cells occupying up to 21% at 3 weeks and up to 68% at 8 weeks of the entire host retina post-grafting. The precursor cells survived well in the adult retina although the most striking feature of the RN33B cell line was its extraordinary migratory capacity. This capability could be useful if precursor cells are used to deliver necessary genes or gene products that need to be distributed over a large diseased area.
|
|
| 9. |
- Christophersen, Nicolaj, et al.
(författare)
-
Induction of dopaminergic neurons from growth factor expanded neural stem/progenitor cell cultures derived from human first trimester forebrain.
- 2006
-
Ingår i: Brain Research Bulletin. - : Elsevier BV. - 0361-9230 .- 1873-2747. ; 70:4-6, s. 457-466
-
Tidskriftsartikel (refereegranskat)abstract
- Multipotent stem/progenitor cells derived from human first trimester forebrain can be expanded as free-floating aggregates, so called neurospheres. These cells can differentiate into neurons, astrocytes and oligodendrocytes. In vitro differentiation protocols normally yield γ-aminobutyric acid-immunoreactive neurons, whereas only few tyrosine hydroxylase (TH) expressing neurons are found. The present report describes conditions under which 4–10% of the cells in the culture become TH immunoreactive (ir) neurons within 24 h. Factors including acidic fibroblast growth factor (aFGF) in combination with agents that increase intracellular cyclic AMP and activate protein kinase C, in addition to a substrate that promotes neuronal differentiation appear critical for efficient TH induction. The cells remain THir after trypsinization and replating, even when their subsequent culturing takes place in the absence of inducing factors. Consistent with a dopaminergic phenotype, mRNAs encoding aromatic acid decarboxylase, but not dopamine-β-hydroxylase were detected by quantitative real time RT-PCR. Ten weeks after the cells had been grafted into the striatum of adult rats with unilateral nigrostriatal lesions, only very few of the surviving human neurons expressed TH. Our data suggest that a significant proportion of expandable human neural progenitors can differentiate into TH-expressing cells in vitro and that they could be useful for drug and gene discovery. Additional experiments, however, are required to improve the survival and phenotypic stability of these cells before they can be considered useful for cell replacement therapy in Parkinson's disease.
|
|
| 10. |
- Dahlin, Lars B., et al.
(författare)
-
Traumatic Peripheral Nerve Injuries : Experimental Models for Repair and Reconstruction
- 2019
-
Ingår i: Animal Models of Neurotrauma. - New York, NY : Springer New York. - 0893-2336 .- 1940-6045. - 9781493997114 - 9781493997091 ; 149, s. 169-186
-
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.
|
|
