| 1. |
- Taylor, Linnéa, et al.
(författare)
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Feet on the ground: Physical support of the inner retina is a strong determinant for cell survival and structural preservation in vitro.
- 2014
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 55:4, s. 2200-2213
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this study was to explore the importance of local physical tissue support for homeostasis in the isolated retina. Methods: Full-thickness retinal sheets were isolated from adult porcine eyes. Retinas were cultured for 5 or 10 days using the previously established explant protocol with photoreceptors positioned against the culture membrane (porous polycarbonate) or the Müller cell endfeet and inner limiting membrane (ILM) apposed against the membrane. The explants were analyzed morphologically using hematoxylin and eosin staining, immunohistochemistry, TUNEL labeling, and transmission electron microscopy (TEM). Results: Standard cultures displayed a progressive loss of retinal lamination and extensive cell death, with activated, hypertrophic Müller cells. In contrast, explants cultured with the ILM facing the membrane displayed a maintenance of the retinal laminar architecture, and a statistically significant attenuation of photoreceptor and ganglion cell death. TEM revealed intact synapses as well as preservation of normal cellular membrane structures. Immunohistochemistry showed no signs of Müller cell activation (GFAP), with maintained expression of important metabolic markers (GS, bFGF). Conclusion: Providing physical support to the inner but not the outer retina appears to prevent the tissue collapse resulting from perturbation of the normal biomechanical milieu in the isolated retinal sheet. Using this novel paradigm, gliotic reactions are attenuated, and metabolic processes vital for tissue health are preserved which significantly increases neuronal cell survival. This finding opens up new avenues of adult retinal tissue culture research, and increases our understanding of pathological reactions in biomechanically related conditions in vivo.
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| 2. |
- Åkerström, Bo, et al.
(författare)
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The Role of Mitochondria, Oxidative Stress, and the Radical-binding Protein A1M in Cultured Porcine Retina.
- 2017
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Ingår i: Current Eye Research. - : Informa UK Limited. - 0271-3683 .- 1460-2202. ; 42:6, s. 948-961
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this study was to explore the relationship between oxidative stress, antioxidant defense, mitochondrial structure, and biomechanical tissue support in the isolated porcine retina.Methods: Full-thickness retinal sheets were isolated from adult porcine eyes. Retinas were cultured for 2 or 48 h using (1) a previously established low-support explant protocol with photoreceptors positioned against the culture membrane (porous polycarbonate) or (2) a high-support procedure developed by our group, apposing the Müller cell endfeet and inner limiting membrane against the membrane. The grafts were analyzed by quantitative polymerase chain reaction (PCR), immunohistochemistry, and transmission electron microscopy (TEM), and culture medium was assayed for the cell damage and oxidative stress markers lactate dehydrogenase and protein carbonyls.Results: In explants cultured with physical support to the inner border, cone photoreceptors were preserved and lactate dehydrogenase levels were reduced, although an initial (2 h), transient, increased oxidative stress was observed. Elevated expression of the antioxidants α1-microglobulin and heme oxygenase-1 was seen in the mitochondria-rich inner segments after 48 h compared to low-support counterparts. Housekeeping gene expression suggested a higher degree of structural integrity of mitochondria in high-support explants, and TEM of inner segments confirmed preservation of a normal mitochondrial morphology.Conclusion: Providing retinal explants with inner retinal support leads to mobilization of antioxidant proteins, preservation of mitochondrial function, and increased cell viability. Consequently, the failure of low-support retinal cultures to mobilize an adequate response to the oxidative environment may play a key role in their rapid demise. These findings shed new light on pathological reactions in biomechanically related conditions in vivo.
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| 3. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 4. |
- Bodén, Linnea, 1981-, et al.
(författare)
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Relational Materialism
- 2020
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Ingår i: The Oxford encyclopedia of qualitative research methods in education. - : Oxford University Press. - 9780190643768 - 9780190643751
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Bokkapitel (refereegranskat)abstract
- Relational materialism was first articulated and framed within Actor Network Theory. In educational research, the concept has emerged with the growing influence of Agential Realism and New Material Feminism, and in the engagements in the “turn to materiality” and/or “turn to ontology.” A relational materialist approach to educational studies can be narrowed down to three key principles: the principle of general symmetry; the principle of material semiotics; and the principle of method. The enactment of relational materialism depends on how these principles come to work in the engagement with central educational problems, such as subjectivity, performativity and practice. Relational materialism takes the starting-point in the problems and concerns of human and material actors or agents, for whom the research can make a difference. While doing so, it acknowledges the methodological difficulties and possibilities when carefully attending simultaneously to discourse, materialities and their relations. Striving towards a methodological sensibility, the enactment of relational materialism in education research entails the emergence and creation of more and multiple methods to know the multiple realities of education. This also makes it possible for relational materialist research to become productive of new and additional educational realities that can, perhaps, make an affirmative difference to the actors or agents concerned.
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| 5. |
- Falck-Ytter, Terje, et al.
(författare)
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The Babytwins Study Sweden (BATSS): A Multi-Method Infant Twin Study of Genetic and Environmental Factors Influencing Infant Brain and Behavioral Development
- 2021
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press (CUP). - 1832-4274 .- 1839-2628. ; 24:4, s. 217-227
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Tidskriftsartikel (refereegranskat)abstract
- Twin studies can help us understand the relative contributions of genes and environment to phenotypic trait variation, including attentional and brain activation measures. In terms of applying methodologies such as electroencephalography (EEG) and eye tracking, which are key methods in developmental neuroscience, infant twin studies are almost nonexistent. Here, we describe the Babytwins Study Sweden (BATSS), a multi-method longitudinal twin study of 177 MZ and 134 DZ twin pairs (i.e., 622 individual infants) covering the 5-36 month time period. The study includes EEG, eye tracking and genetics, together with more traditional measures based on in-person testing, direct observation and questionnaires. The results show that interest in participation in research among twin parents is high, despite the comprehensive protocol. DNA analysis from saliva samples was possible in virtually all participants, allowing for both zygosity confirmation and polygenic score analyses. Combining a longitudinal twin design with advanced technologies in developmental cognitive neuroscience and genomics, BATSS represents a new approach in infancy research, which we hope to have impact across multiple disciplines in the coming years.
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| 6. |
- Ghosh, Fredrik, et al.
(författare)
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Acute tissue reactions, inner segment pathology, and effects of the antioxidant α1-microglobulin in an in vitro model of retinal detachment
- 2018
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835. ; 173, s. 13-23
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to explore acute tissue reactions, ultrastructural photoreceptor morphology with emphasis on inner segments, and the effect of antioxidant treatment in an in vitro model of rhegmatogenous retinal detachment (RRD). A previously described method of RRD simulation was used with adult retinal porcine explants kept free-floating in culture medium with or without treatment with the radical scavenger α1-microglobulin (A1M). Explants were examined at 5 time points from 1 to 24 h using transmission electron microscopy as well as quantitative real-time PCR (RT-PCR) to quantify gene expression of the cell stress marker heat shock protein 70 (Hsp70) and oxidative stress marker heme oxygenase (HO-1). The culture medium level of the cell damage marker lactate dehydrogenase (LDH) and oxidative stress DNA damage marker 8-Oxo-2'-deoxyguanosine (8-OHdG) was also assessed at each time point. We found that the levels of Hsp70 and LDH rapidly increased in both groups, and at 3 and 6 h, Hsp70 was significantly higher in A1M treated retinas. At 24 h, Hsp70 and LDH, as well as 8-OHdG were significantly lower compared with controls, whereas the tissue level of HO-1 was significantly higher. Progressive ultrastructural photoreceptor changes were seen in untreated control explants from 1 h and onwards including outer segment shortening and loss, disruption of organelles within the inner segments and loss of perikarya in the outer nuclear layer. Inner segment pathology was more rapid and extensive in rods compared with in cones. In A1M treated counterparts, damage to rod inner segment mitochondria was significantly higher after 1 h of culture, but after this time, no statistical difference was found. At 24 h, cone inner segment mitochondrial disruption was significantly higher in control retinas and the number of surviving perikarya lower. From our results, we conclude that retinal explants elicit acute cell stress reactions when placed in culture without physical support simulating a detached retina floating in the vitreous space. Photoreceptors rapidly display degenerative changes including extensive damage to inner segment mitochondria indicating loss of energy transduction as an early key event. A1M increases initial mitochondrial stress in the rods, however, subsequent pathology is attenuated by the treatment, highlighting the dynamics of protective as well as disruptive oxidative stress reactions in the detached retina.
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| 7. |
- Ghosh, Fredrik, et al.
(författare)
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Exogenous Glutamate Modulates Porcine Retinal Development in vitro.
- 2012
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Ingår i: Developmental Neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866.
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Tidskriftsartikel (refereegranskat)abstract
- Embryogenesis of the retina is a complex event orchestrated by a multitude of physical and biochemical signals. To study the impact of intrinsic developmental cues, the retinal tissue can be isolated in culture which also enables modulation of normal development for other purposes, i.e. transplantation of specific neuronal cell types. In the present experiment, cell type development of immature porcine retinal tissue kept in culture was explored using specific immunohistochemical markers. Retinal explants were either kept under standard culture conditions or supplemented with glutamate and their morphology was compared with in vivo controls of corresponding age. After 15 days in vitro (DIV), E45 retinal explants displayed several signs of atypical development when compared with E60 in vivo controls. First, an accelerated photoreceptor differentiation was evident, seen in sections labeled with antibodies directed against recoverin, rhodopsin and synaptophysin. Second, apoptotic cells in the inner retina were more prevalent in the cultured retinas (TUNEL). Rod photoreceptor differentiation as well as inner retinal apoptosis was even more pronounced in glutamate-supplemented specimens in which they occurred already at 8 DIV. Müller cell, vimentin and GFAP expression was not affected in any of the cultured retinas. These results suggest that normal retinal embryogenesis is more dependent on tissue extrinsic factors than what has been deduced from previous small animal experiments. Glutamate, which has been identified as an important regulator of cell cycle exit, may also be important for photoreceptor differentiation and induction of developmental apoptosis. Insights into retinal cell type differentiation under in vitro conditions is of interest from a biological standpoint, and the possibility of modulation of this process is valuable for research directed towards cell replacement in retinal degenerative disease.
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| 8. |
- Ghosh, Fredrik, et al.
(författare)
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In vitro biomechanical modulation-retinal detachment in a box.
- 2016
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Ingår i: Graefe's Archive for Clinical and Experimental Ophthalmology. - : Springer Science and Business Media LLC. - 1435-702X .- 0721-832X. ; 254:3, s. 475-487
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Tidskriftsartikel (refereegranskat)abstract
- To illustrate the importance of biomechanical impact on tissue health within the central nervous system (CNS), we herein describe an in vitro model of rhegmatogenous retinal detachment (RRD) in which disruption and restoration of physical tissue support can be studied in isolation.
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| 9. |
- Ghosh, Fredrik, et al.
(författare)
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Retinal neuroinflammatory induced neuronal degeneration - Role of toll-like receptor-4 and relationship with gliosis
- 2018
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835. ; 169, s. 99-110
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to explore retina-intrinsic neuroinflammatory reactions, effects on neuronal survival, relationship with classic gliosis, and possible role of the toll-like receptor 4 (TLR4). To isolate the adult retina from the systemic immune system, a previously described large animal explant culture model was used in which full-thickness porcine retinal sheets can be kept in vitro for extended time periods. Explants were kept for 5 days in vitro (DIV) and were treated with either; lipopolysaccharide (LPS), a Toll-like receptor-4 (TLR4) inhibitor (CLI-095), LPS + CLI-095, or solvent vehicle throughout the culture period after which retinal sections were examined with hematoxylin and eosin staining and extensive immunohistochemistry. In addition, the culture medium of all explants was assayed for a panel of cytokines at 2 and 5DIV. Compared with in vivo controls, vehicle controls (CT) as well as CLI-095 explants displayed moderate reduction of total thickness and number of retinal neurons with upregulation of glial fibrillary acidic protein (GFAP) throughout the Müller cells. In contrast, LPS and LPS + CLI-095 treated counterparts showed extensive overall thinning with widespread neuronal degeneration but only minimal signs of classical Müller cell gliosis (limited upregulation of GFAP and no downregulation of glutamine synthetase (GS). These specimens also displayed a significantly increased expression of galectin-3 and TGF-beta activated kinase 1 (TAK1). Multiplex proteomic analysis of culture medium at 2DIV revealed elevated levels of IL-1β, IL-6, IL-4 and IL-12 in LPS-treated explants compared to CLI-095 and CT counterparts. LPS stimulation of the isolated adult retina results in substantial neuronal cell death despite only minimal signs of gliosis indicating a retina-intrinsic neuroinflammatory response directly related to the degenerative process. This response is characterized by early upregulation of several inflammatory related cytokines with subsequent upregulation of Galectin-3, TLR4 and TAK1. Pharmacological block of TLR4 does not attenuate neuronal loss indicating that LPS induced retinal degeneration is mediated by TLR4 independent neuroinflammatory pathways.
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| 10. |
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| 11. |
- Manouchehrian, Oscar, et al.
(författare)
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Who let the dogs out?: detrimental role of Galectin-3 in hypoperfusion-induced retinal degeneration.
- 2015
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundRetinal ischemia results in a progressive degeneration of neurons and a pathological activation of glial cells, resulting in vision loss. In the brain, progressive damage after ischemic insult has been correlated to neuroinflammatory processes involving microglia. Galectin-3 has been shown to mediate microglial responses to ischemic injury in the brain. Therefore, we wanted to explore the contribution of Galectin-3 (Gal-3) to hypoperfusion-induced retinal degeneration in mice.MethodsGal-3 knockout (Gal-3 KO) and wildtype (WT) C57BL/6 mice were subjected to chronic cerebral hypoperfusion by bilateral narrowing of the common carotid arteries using metal coils resulting in a 30% reduction of blood flow. Sham operated mice served as controls. After 17 weeks, the mice were sacrificed and the eyes were analyzed for retinal architecture, neuronal cell survival, and glial reactivity using morphological staining and immunohistochemistry.ResultsHypoperfusion caused a strong increase in Gal-3 expression and microglial activation in WT mice, coupled with severe degenerative damage to all retinal neuronal subtypes, remodeling of the retinal lamination and Müller cell gliosis. In contrast, hypoperfused Gal-3 KO mice displayed a retained laminar architecture, a significant preservation of photoreceptors and ganglion cell neurons, and an attenuation of microglial and Müller cell activation.ConclusionModerate cerebral blood flow reduction in the mouse results in severe retinal degenerative damage. In mice lacking Gal-3 expression, pathological changes are significantly attenuated. Gal-3 is thereby a potential target for treatment and prevention of hypoperfusion-induced retinal degeneration and a strong candidate for further research as a factor behind retinal degenerative disease.
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| 12. |
- Mohlin, Camilla, et al.
(författare)
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Autophagy and ER-stress contribute to photoreceptor degeneration in cultured adult porcine retina
- 2014
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Ingår i: Brain Research. - : Elsevier BV. - 0006-8993 .- 1872-6240. ; 1585, s. 167-183
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate rod and cone photoreceptor degeneration in organotypic cultures of adult porcine retina. Our hypothesis was that the photoreceptors accumulate opsins, which, together with exposure to cyclic dim light illumination, induce autophagy and endoplasmic reticulum stress (ER-stress) to overcome damaging protein overload. For this purpose, retinas were cultured for 48 h and 72 h during which they were illuminated with dim light for 8 h/day; specimens were analyzed by means of immunohistochemistry, Western blot, real-time polymerase chain reaction (PCR) and transmission electron microscopy. ER-stress and photoreceptor degeneration was observed in conventionally cultured retinas. The additional stress in the form of dim light illumination for 8 h/day resulted in increased levels of the ER-stress markers GRP78/BiP and CHOP, as well as increased level of active caspase-12. Increased autophagic processes in cone and rod photoreceptors were detected by LC3B-II increases and occurrence of autophagosomes at the ultrastructural level. Illumination also resulted in altered protein expression for autophagy inducers such as p62 and Beclin-1. Moreover, there was a decrease in phosphorylated mammalian target of rapamycin (mTOR), which further indicate an increase of autophagy. Rod and cone photoreceptors in retinas from a diurnal animal that were exposed to dim light illumination in vitro displayed autophagy and ER-stress processes. As no alteration of rhodopsin mRNA was observed, autophagy and ER-stress are suggested to decrease rhodopsin protein at the posttranscriptional level.
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| 13. |
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| 14. |
- Robinson-Cohen, Cassianne, et al.
(författare)
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Genetic Variants Associated with Circulating Fibroblast Growth Factor 23
- 2018
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Ingår i: Journal of the American Society of Nephrology. - : AMER SOC NEPHROLOGY. - 1046-6673 .- 1533-3450. ; 29:10, s. 2583-2592
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Tidskriftsartikel (refereegranskat)abstract
- Background: Fibroblast growth factor 23 (FGF23), a bone-derived hormone that regulates phosphorus and vitamin D metabolism, contributes to the pathogenesis of mineral and bone disorders in CKD and is an emerging cardiovascular risk factor. Central elements of FGF23 regulation remain incompletely understood; genetic variation may help explain interindividual differences.Methods: We performed a meta-analysis of genome-wide association studies of circulating FGF23 concentrations among 16,624 participants of European ancestry from seven cohort studies, excluding participants with eGFR<30 ml/min per 1.73 m(2) to focus on FGF23 under normal conditions. We evaluated the association of single-nucleotide polymorphisms (SNPs) with natural log-transformed FGF23 concentration, adjusted for age, sex, study site, and principal components of ancestry. A second model additionally adjusted for BMI and eGFR.Results: We discovered 154 SNPs from five independent regions associated with FGF23 concentration. The SNP with the strongest association, rs17216707 (P=3.0x10(-24)), lies upstream of CYP24A1, which encodes the primary catabolic enzyme for 1,25-dihydroxyvitamin D and 25-hydroxyvitamin D. Each additional copy of the T allele at this locus is associated with 5% higher FGF23 concentration. Another locus strongly associated with variations in FGF23 concentration is rs11741640, within RGS14 and upstream of SLC34A1 (a gene involved in renal phosphate transport). Additional adjustment for BMI and eGFR did not materially alter the magnitude of these associations. Another top locus (within ABO, the ABO blood group transferase gene) was no longer statistically significant at the genome-wide level.Conclusions: Common genetic variants located near genes involved in vitamin D metabolism and renal phosphate transport are associated with differences in circulating FGF23 concentrations.
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| 15. |
- Sparrman, Anna, 1965-, et al.
(författare)
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Child Studies Multiple : Collaborative play for thinking through theories and methods
- 2023
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Ingår i: Culture Unbound. - : Linköping University Electronic Press. - 2000-1525. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- This text is an exploration of collaborative thinking and writing through theories, methods, and experiences on the topic of the child, children, and childhood. It is a collaborative written text (with 32 authors) that sprang out of the experimental workshop Child Studies Multiple. The workshop and this text are about daring to stay with mess, “un-closure” , and uncertainty in order to investigate the (e)motions and complexities of being either a child or a researcher. The theoretical and methodological processes presented here offer an opportunity to shake the ground on which individual researchers stand by raising questions about scientific inspiration, theoretical and methodological productivity, and thinking through focusing on process, play, and collaboration. The effect of this is a questioning of the singular academic ‘I’ by exploring and showing what a plural ‘I’ can look like. It is about what the multiplicity of voice can offer research in a highly individualistic time. The article allows the reader to follow and watch the unconventional trial-and-error path of the ongoing-ness of exploring theories and methods together as a research community via methods of drama, palimpsest, and fictionary.
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| 16. |
- Sparve, Erik, et al.
(författare)
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Prediction and Modeling of Effects on the QTc Interval for Clinical Safety Margin Assessment, Based on Single-Ascending-Dose Study Data with AZD3839
- 2014
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Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 350:2, s. 469-478
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Tidskriftsartikel (refereegranskat)abstract
- Corrected QT interval (QTc) prolongation in humans is usually predictable based on results from preclinical findings. This study confirms the signal from preclinical cardiac repolarization models (human ether-a-go-go-related gene, guinea pig monophasic action potential, and dog telemetry) on the clinical effects on the QTc interval. A thorough QT/QTc study is generally required for bioavailable pharmaceutical compounds to determine whether or not a drug shows a QTc effect above a threshold of regulatory interest. However, as demonstrated in this AZD3839 [(S)-1-(2-(difluoromethyl)pyridin-4-yl)-4-fluoro-1-(3-(pyrimidin-5-yl)phenyl)-1H-isoindol-3-amine hemifumarate] single-ascending-dose (SAD) study, high-resolution digital electrocardiogram data, in combination with adequate efficacy biomarker and pharmacokinetic data and nonlinear mixed effects modeling, can provide the basis to safely explore the margins to allow for robust modeling of clinical effect versus the electrophysiological risk marker. We also conclude that a carefully conducted SAD study may provide reliable data for effective early strategic decision making ahead of the thorough QT/QTc study.
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| 17. |
- Taylor, Linnéa
(författare)
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Biochemical and biomechanical modulation of the in vitro retina
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The porcine retinal explant culture paradigm offers the possibility to study retinal health, disease and development independently from the surrounding tissues of the eye. Retina-intrinsic effects of molecular and mechanical cues on the isolated retinal sheet can thus be studied with great precision. For the purpose of creating a donor tissue optimized for transplantation, we used this system to explore the impact of biochemical modulation on cell survival and embryogenesis. Further, biomechanical modulation and its significance in retinal homeostasis was investigated. Biochemical modulation of the embryonic retina using glutamate revealed an accelerated photoreceptor maturation coupled with increased developmental apoptosis in the inner layers. In adult tissue, glial cell-derived neurotrophic factor (GDNF) treatment was found to increase photoreceptor cell survival and attenuate gliosis. These results demonstrate the potential of biochemical modulation in the creation of a donor tissue well adapted for retinal transplantation. Biomechanical modulation through emulation of the tissue tension and inner retinal support found in the living eye was found to significantly increase neuronal survival and preserve glial structure and function in adult explants. The results demonstrate the importance of the biomechanical milieu for retinal homeostasis and provide an important link between glial cell health and neuronal preservation. In conclusion, we have shown that biochemical and biomechanical modulation of the porcine retina in vitro can be used to modify development and enhance cell survival. The findings provide further understanding of mechanisms behind retinal disease and reveals new avenues in the search for treatment of degenerative retinal disease.
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| 18. |
- Taylor, Linnéa, et al.
(författare)
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Complimentary action : C1q increases ganglion cell survival in an in vitro model of retinal degeneration
- 2016
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Ingår i: Journal of Neuroimmunology. - : Elsevier BV. - 0165-5728. ; 298, s. 117-129
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Tidskriftsartikel (refereegranskat)abstract
- Using a previously described retinal explant culture system as an acute injury model, we here explore the role of C1q, the initiator of the classical complement pathway, in neuronal cell survival and retinal homeostasis. Full-thickness adult rat retinal explants were divided into four groups, receiving the following supplementation: C1q (50 nM), C1-inhibitor (C1-inh; Berinert; 500 mg/l), C1q + C1-inh, and no supplementation (culture controls). Explants were kept for 12 h or 2 days after which they were examined morphologically and with a panel of immunohistochemical markers. C1q supplementation protects ganglion cells from degeneration within the explant in vitro system. This effect is correlated to an attenuated endogenous production of C1q, and a quiesced gliotic response.
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| 19. |
- Taylor, Linnéa, et al.
(författare)
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Effects of Glial Cell Line-derived Neurotrophic Factor on the Cultured Adult Full-thickness Porcine Retina.
- 2013
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Ingår i: Current Eye Research. - : Informa UK Limited. - 0271-3683 .- 1460-2202. ; 38:4, s. 503-515
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background: The tissue culture system offers a possibility to study factors involved in neuronal survival which may be important in a transplantation paradigm. The use of adult tissue in this setting poses specific challenges since traditionally mature neurons survive poorly in vitro. In the current paper, we have explored effects of glial cell line-derived neurotrophic factor (GDNF) on cultures of adult porcine retina. Methods: Full-thickness retinal sheets were isolated from adult porcine eyes and were cultured for 5 or 10 days under standard culture conditions with or without GDNF added to the culture medium. The grafts were analyzed morphologically using hematoxylin and eosin staining, immunohistochemistry and transferase dUTP nick end labeling (TUNEL) labeling. Retinas derived from normal adult porcine eyes were used as controls. Results: After 5 d in vitro (DIV), cultures without GDNF showed dissolving retinal lamination while specimens cultured with GDNF displayed the normal laminated morphology. At 10 DIV, the untreated cultures had been reduced to a degenerated cell mass, while the GDNF-cultured specimens retained thin but distinguishable retinal layers. TUNEL labeling confirmed these results. Immunohistochemical labelings and outer nuclear layer thickness measurements showed an increased preservation of photoreceptors and horizontal cells in the GDNF-treated group. Conclusions: The procedure of culturing retina involves several steps causing severe traumatic effects on the tissue, such as ganglion cell axotomy, interruption of the blood flow as well as separation from the retinal pigment epithelium (RPE). In this paper, we have shown that addition of GDNF in the culture medium attenuates the effect of these steps, resulting in enhanced preservation of several retinal neuronal subtypes. The results may be of importance for research in retinal transplantation where storage time of the donor tissue prior to transplantation is a critical issue.
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| 20. |
- Taylor, Linnéa, et al.
(författare)
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First Responders: Dynamics of Pre-Gliotic Müller Cell Responses in The Isolated Adult Rat Retina.
- 2015
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Ingår i: Current Eye Research. - : Informa UK Limited. - 0271-3683 .- 1460-2202. ; 40:12, s. 1245-1260
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Purpose: To explore the early reactions of the retinal Müller glia in response to retinal insult prior to gliotic remodeling and the sustained upregulation of intermediate filament glial fibrillary acidic protein (GFAP), which has traditionally been considered the most sensitive early indicator of reactive gliosis. Methods: To study pre-gliotic events, we used a model of adult rat retinal explants and related the dynamic expression of GFAP as well as apoptosis, to four key regulators of retinal homeostasis (glutamine synthetase (GS), cellular retinaldehyde binding protein (CRALBP), basic fibroblast growth factor (bFGF), carbonic anhydrase II (CAII)) using immunohistochemistry. Results: We found that a sustained GFAP upregulation couple with gliotic remodeling occurred comparatively late and that this phenomenon was preceded by an initial upregulation followed by depletion of GS, CRALBP, bFGF and CAII in retinal Müller cells. The initial increase of the regulatory proteins, seen after 1-12 h, preceded a first phase of moderate apoptosis, and their depletion after 48 h was followed by massive apoptosis and widespread GFAP upregulation in the Müller cells at 5 days. Conclusion: We conclude that, in the explant model, changes in the expression of the four homeostatic regulatory proteins as well as apoptotic cell death precedes sustained GFAP upregulation and reactive gliosis. Müller cell reactivity has been linked to several retinal conditions, and the herein provided novel information on the dynamics of pre-gliotic events in the lesioned retina may help us understand important pathological mechanisms crucial for future therapeutic intervention.
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| 21. |
- Taylor, Linnéa, et al.
(författare)
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N-methyl-N-nitrosourea-induced neuronal cell death in a large animal model of retinal degeneration in vitro
- 2016
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835. ; 148, s. 55-64
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Tidskriftsartikel (refereegranskat)abstract
- N-methyl-N-nitrosourea (MNU) has been reported to induce photoreceptor-specific degeneration with minimal inner retinal impact in small animals in vivo. Pending its use within a retinal transplantation paradigm, we here explore the effects of MNU on outer and inner retinal neurons and glia in an in vitro large animal model of retinal degeneration. The previously described degenerative culture explant model of adult porcine retina was used and compared with explants receiving 10 or 100 μg/ml MNU (MNU10 and MNU100) supplementation. All explants were kept for 5 days in vitro, and examined for morphology as well as for glial and neuronal immunohistochemical markers. Rhodopsin-labeled photoreceptors were present in all explants. The number of cone photoreceptors (transducin), rod bipolar cells (PKC) and horizontal cells (calbindin) was significantly lower in MNU treated explants (p <0.001). Gliosis was attenuated in MNU10 treated explants, with expression of vimentin, glial fibrillary protein (GFAP), glutamine synthetase (GS), and bFGF comparable to in vivo controls. In corresponding MNU100 counterparts, the expression of Müller cell proteins was almost extinguished. We here show that MNU causes degeneration of outer and inner retinal neurons and glia in the adult porcine retina in vitro. MNU10 explants display attenuation of gliosis, despite decreased neuronal survival compared with untreated controls. Our results have impact on the use of MNU as a large animal photoreceptor degeneration model, on tissue engineering related to retinal transplantation, and on our understanding of gliosis related neuronal degenerative cell death.
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| 22. |
- Taylor, Linnéa, et al.
(författare)
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Scaffolding the retina: The interstitial extracellular matrix during rat retinal development.
- 2015
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Ingår i: International Journal of Developmental Neuroscience. - : Wiley. - 1873-474X .- 0736-5748. ; 42, s. 46-58
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To examine the expression of interstitial extracellular matrix components and their role during retinal development. MATERIAL AND METHODS: Fibronectin (FN), collagen IV (Coll IV) and laminin 5 (Lam 5) expression in rat retinas from developmental stages E17 to adult were studied. In addition, PN5 full-thickness retinas were cultured for 7 days with dispase, which selectively cleaves FN and Coll IV, at either 0.5U/ml or 5.0U/ml for 3 or 24h. Eyecups and retinal cultures were examined morphologically using hematoxylin and eosin staining and immunohistochemistry. RESULTS: Coll IV, Lam 5 and FN were all transiently expressed in the interstitial matrix of the retinal layers during development. The retinal layers in dispase treated explants was severely disturbed in a dose and time dependent manner. CONCLUSIONS: FN, Lam 5 and Coll IV, are present in the interstitial extracellular matrix during rat retinal development. Enzymatic cleavage of FN and Coll IV early in the lamination process disrupts the retinal layers implicating their pivotal role in this process.
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| 23. |
- Taylor, Linnéa, et al.
(författare)
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Seeing through the interface : Poly(ε-Caprolactone) surface modification of poly(glycerol-co-sebacic acid) membranes in adult porcine retinal explants
- 2017
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Ingår i: Journal of Tissue Engineering and Regenerative Medicine. - : Hindawi Limited. - 1932-6254. ; 11:8, s. 2349-2358
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the adhesion properties and tissue reactions in an in vitro model of nanofabricated membranes emulating the vitreous cortex. Electrospinning was performed for either 5, 10 or 15 min to create various thicknesses of poly(ε-caprolactone) (PCL) fibre mats on a poly(glycerol-co-sebacic acid) (PGS) surface. These were fused with adult porcine retinal explants, with the fibre side facing the inner retina, and cultured for 5 days. Adherence was assessed by macroscopic inspection, and morphological and immunohistochemical analysis was performed using haematoxylin and eosin (H&E) and markers for photoreceptors and Müller glia (recoverin, NeuN, vimentin and GFAP). TUNEL labelling was performed to assess apoptosis. Five minute specimens displayed poor adherence with an overall structure, apoptosis and photoreceptor and ganglion cell morphology comparable to that of the culture controls, whereas 10 min specimens showed improved neuronal survival; 15 min composite explants adhered only at focal points, were thin and showed extensive degenerative damage. The physical composition of nanofibre meshes is important for adhesion to the inner retina and has a significant impact on neuronal and glial survival in vitro. The results bearing on research involving retinal transplantation are discussed.
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| 24. |
- Taylor, Linnéa, et al.
(författare)
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Specific inhibition of TRPV4 enhances retinal ganglion cell survival in adult porcine retinal explants
- 2017
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835. ; 154, s. 10-21
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Tidskriftsartikel (refereegranskat)abstract
- Signaling through the polymodal cation channel Transient Receptor Potential Vanilloid 4 (TRPV4) has been implicated in retinal neuronal degeneration. To further outline the involvement of this channel in this process, we here explore modulation of Transient Receptor Potential Vanilloid 4 (TRPV4) activity on neuronal health and glial activation in an in vitro model of retinal degeneration. For this purpose, adult porcine retinal explants were cultured using a previously established standard protocol for up to 5 days with specific TRPV4 agonist GSK1016790A (GSK), or specific antagonist RN-1734, or culture medium only. Glial and neuronal cell health were evaluated by a battery of immunohistochemical markers, as well as morphological staining. Specific inhibition of TRPV4 by RN-1734 significantly enhanced ganglion cell survival, improved the maintenance of the retinal laminar architecture, reduced apoptotic cell death and attenuated the gliotic response as well as preserved the expression of TRPV4 in the plexiform layers and ganglion cells. In contrast, culture controls, as well as specimens treated with GSK, displayed rapid remodeling and neurodegeneration as well as a downregulation of TRPV4 and the Müller cell homeostatic mediator glutamine synthetase. Our results indicate that TRPV4 signaling is an important contributor to the retinal degeneration in this model, affecting neuronal cell health and glial homeostasis. The finding that pharmacological inhibition of the receptor significantly attenuates neuronal degeneration and gliosis in vitro, suggests that TRPV4 signaling may be an interesting pharmaceutical target to explore for treatment of retinal degenerative disease.
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| 25. |
- Taylor, Linnéa, et al.
(författare)
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Stretch To See - Lateral tension strongly determines cell survival in long-term cultures of adult porcine retina.
- 2013
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 54:3, s. 1845-1856
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this study is to explore the effect of lateral tension as a survival factor for retinal explants in vitro. The central nervous system (CNS) resides in a highly mechanical milieu. However, the importance of biomechanical homeostasis for normal CNS function has not been extensively explored. Diseases in which normal mechanical forces are disrupted, such as retinal detachment of the eye, are highly debilitating and the mechanisms underlying disease progression are not fully understood. METHODS: Using a porcine animal model, we developed a novel technique of culturing adult retinal explants under stretch for up to 10 days in vitro (DIV). These were compared to standard (no stretch) and free-floating cultured explants. Cell survival was analysed using immunohistochemistry, and retinal architecture using hematoxylin and eosin staining. RESULTS: Compared to unstretched specimens, which at 10 DIV degenerate into a gliotic cell mass, stretched retinas display a profound preservation of the laminar retinal architecture as well as significantly increased neuronal cell survival, with no signs of impending gliosis. CONCLUSIONS: The results confirm that biomechanical tension is a vital factor in the maintenance of retinal tissue integrity, and suggest that mechanical cues are important components of pathological responses within the CNS.
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| 26. |
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