| 1. |
- Blomstrand, Malin, 1974, et al.
(författare)
-
No clinically relevant effect on cognitive outcomes after low-dose radiation to the infant brain: A population-based cohort study in Sweden
- 2014
-
Ingår i: Acta Oncologica. - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 53:9, s. 1143-1150
-
Tidskriftsartikel (refereegranskat)abstract
- While the detrimental effects of cranial radiotherapy on the developing brain are well known, the effects on cognitive performance of low doses of ionizing radiation is less studied. We performed a population-based cohort study to determine whether low doses of ionizing radiation to the brain in infancy affects cognitive function later in life. Further we hypothesized that the dose to the hippocampus predicts cognitive late side effects better than the anterior or the posterior brain doses. Material and methods. During 1950 - 1960 3860 boys were treated with radiation in Sweden for cutaneous hemangiomas before the age of 18 months. Of these, 3030 were analyzed for military test scores at the age of 18 years and 2559 for the highest obtained educational level. Results. Logical, spatial and technical test scores were not affected by increasing irradiation doses. The verbal test scores displayed a significant trend for decreasing scores with increasing doses to the hippocampus (p = 0.005). However, the absolute mean difference between the zero dose and the highest dose category (median 680 mGy) was very small, only 0.64 stanine points, and the significance was dependent on the highest dose category, containing few subjects. The educational level was not affected by brain irradiation. Overall, the hippocampal dose was a better predictor of late cognitive side effects than the doses to the anterior or the posterior brain. In conclusion, there was no decrease in logical, spatial and technical verbal or global test scores after ionizing radiation doses up to 250 mGy, but a subtle decrease in verbal test scores if the highest dose category was included (median 680 mGy). However, the clinical relevance of this decline in the highest dose group is questionable, since we could not find any effect on the highest obtained educational level.
|
|
| 2. |
- Fleiss, Bobbi, et al.
(författare)
-
Neuroprotection by the histone deacetylase inhibitor trichostatin A in a model of lipopolysaccharide-sensitised neonatal hypoxic-ischaemic brain injury.
- 2012
-
Ingår i: Journal of neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: Perinatal brain injury is complex and often associated with both inflammation and hypoxia-ischaemia (HI). In adult inflammatory brain injury models, therapies to increase acetylation are efficacious in reducing inflammation and cerebral injury. Our aim in the present study was to examine the neuropathological and functional effects of the histone deacetylase inhibitor (HDACi) trichostatin A (TSA) in a model of neonatal lipopolysaccharide (LPS)-sensitised HI. We hypothesised that, by decreasing inflammation, TSA would improve injury and behavioural outcome. Furthermore, TSA's effects on oligodendrocyte development, which is acetylation-dependent, were investigated. METHODS: On postnatal day 8 (P8), male and female mice were exposed to LPS together with or without TSA. On P9 (14 hours after LPS), mice were exposed to HI (50 minutes at 10% O2). Neuropathology was assessed at 24 hours, 5 days and 27 days post-LPS/HI via immunohistochemistry and/or Western blot analysis for markers of grey matter (microtubule-associated protein 2), white matter (myelin basic protein) and cell death (activated caspase-3). Effects of TSA on LPS or LPS/HI-induced inflammation (cytokines and microglia number) were assessed by Luminex assay and immunohistochemistry. Expression of acetylation-dependent oligodendrocyte maturational corepressors was assessed with quantitative PCR 6 hours after LPS and at 24 hours and 27 days post-LPS/HI. Animal behaviour was monitored with the open-field and trace fear-conditioning paradigms at 25 days post-LPS/HI to identify functional implications of changes in neuropathology associated with TSA treatment. RESULTS: TSA increased acetylation in females after LPS exposure, but not in males. Also only in females, TSA reduced grey matter and white matter injury at 5 days post-LPS/HI. TSA treatment altered animal behaviour in the open field and improved learning in the fear-conditioning test in females compared with LPS/HI only females at 25 days post-HI. None of the inflammatory mechanisms assessed that are known to mediate neuroprotection by HDACi in adults correlated with improved outcome in TSA-treated neonatal females. Oligodendrocyte maturation was not different between the LPS-only and LPS + TSA-treated mice before or after exposure to HI. CONCLUSIONS: Hyperacetylation with TSA is neuroprotective in the female neonatal mouse following LPS/HI and correlates with improved learning long-term. TSA appears to exert neuroprotection via mechanisms unique to the neonate. Deciphering the effects of age, sex and inflammatory sensitisation in the cerebral response to HDACi is key to furthering the potential of hyperacetylation as a viable neuroprotectant. TSA did not impair oligodendrocyte maturation, which increases the possible clinical relevance of this strategy.
|
|
| 3. |
- Gustafsson Brywe, Katarina, 1965, et al.
(författare)
-
IGF-I neuroprotection in the immature brain after hypoxia-ischemia, involvement of Akt and GSK3beta?
- 2005
-
Ingår i: Eur J Neurosci. - : Wiley. - 0953-816X. ; 21:6, s. 1489-502
-
Tidskriftsartikel (refereegranskat)abstract
- Insulin-like growth factor I (IGF-I) is a neurotrophic factor that promotes neuronal growth, differentiation and survival. Neuroprotective effects of IGF-I have previously been shown in adult and juvenile rat models of brain injury. We wanted to investigate the neuroprotective effect of IGF-I after hypoxia-ischemia (HI) in 7-day-old neonatal rats and the mechanisms of IGF-I actions in vivo. We also wanted to study effects of HI and/or IGF-I on the serine/threonine kinases Akt and glycogen synthase kinase 3beta (GSK3beta) in the phophatidylinositol-3 kinase (PI3K) pathway. Immediately after HI, phosphorylated Akt (pAkt) and phosphorylated GSK3beta (pGSK3beta) immunoreactivity was lost in the ipsilateral and reduced in the contralateral hemisphere. After 45 min, pAkt levels were restored to control values, whereas pGSK3beta remained low 4 h after HI. Administration of IGF-I (50 microg i.c.v.) after HI resulted in a 40% reduction in brain damage (loss of microtubule-associated protein) compared with vehicle-treated animals. IGF-I treatment without HI was shown to increase pAkt whereas pGSK3beta decreased in the cytosol, but increased in the nuclear fraction. IGF-I treatment after HI increased pAkt in the cytosol and pGSK3beta in both the cytosol and the nuclear fraction in the ipsilateral hemisphere compared with vehicle-treated rats, concomitant with a reduced caspase-3- and caspase-9-like activity. In conclusion, IGF-I induces activation of Akt during recovery after HI which, in combination with inactivation of GSK3beta, may explain the attenuated activation of caspases and reduction of injury in the immature brain.
|
|
| 4. |
- Karlsson, Niklas, et al.
(författare)
-
Learning and activity after irradiation of the young mouse brain analyzed in adulthood using unbiased monitoring in a home cage environment.
- 2011
-
Ingår i: Radiation research. - 1938-5404. ; 175:3, s. 336-46
-
Tidskriftsartikel (refereegranskat)abstract
- Cranial radiotherapy during the treatment of pediatric malignancies may cause adverse late effects. It is important to find methods to assess the functional effects of ionizing radiation in animal models and to evaluate the possible ameliorating effects of preventive or reparative treatment strategies. We investigated the long-term effects of a single 8-Gy radiation dose to the brains of 14-day-old mice. Activity and learning were evaluated in adulthood using open field and trace fear conditioning (TFC). These established methods were compared with the novel IntelliCage platform, which enables unbiased analysis of both activity and learning over time in a home cage environment. Neither activity nor learning was changed after irradiation, as judged by the open field and TFC analyses. The IntelliCage, however, revealed both altered activity and learning impairment after irradiation. Place learning and reversal learning were both impaired in the IntelliCage 3 months after irradiation. These results indicate that activity and learning should be assessed using multiple methods and that unbiased analysis over time in a home cage environment may offer advantages in the detection of subtle radiation-induced effects on the young brain.
|
|
| 5. |
- Wang, Xiaoyang, 1965, et al.
(författare)
-
Developmental shift of cyclophilin D contribution to hypoxic-ischemic brain injury.
- 2009
-
Ingår i: The Journal of neuroscience : the official journal of the Society for Neuroscience. - 1529-2401. ; 29:8, s. 2588-96
-
Tidskriftsartikel (refereegranskat)abstract
- Cyclophilin D (CypD), a regulator of the mitochondrial membrane permeability transition pore (PTP), enhances Ca(2+)-induced mitochondrial permeabilization and cell death in the brain. However, the role of CypD in hypoxic-ischemic (HI) brain injury at different developmental ages is unknown. At postnatal day (P) 9 or P60, littermates of CypD-deficient [knock-out (KO)], wild-type (WT), and heterozygous mice were subjected to HI, and brain injury was evaluated 7 d after HI. CypD deficiency resulted in a significant reduction of HI brain injury at P60 but worsened injury at P9. After HI, caspase-dependent and -independent cell death pathways were more induced in P9 CypD KO mice than in WT controls, and apoptotic activation was minimal at P60. The PTP had a considerably higher induction threshold and lower sensitivity to cyclosporin A in neonatal versus adult mice. On the contrary, Bax inhibition markedly reduced caspase activation and brain injury in immature mice but was ineffective in the adult brain. Our findings suggest that CypD/PTP is critical for the development of brain injury in the adult, whereas Bax-dependent mechanisms prevail in the immature brain. The role of CypD in HI shifts from a predominantly prosurvival protein in the immature to a cell death mediator in the adult brain.
|
|
| 6. |
- Aoyama, K., et al.
(författare)
-
Cleavage of integrin by mu-calpain during hypoxia in human endometrial cells
- 2004
-
Ingår i: Am J Reprod Immunol. - 1046-7408. ; 52:6, s. 362-9
-
Tidskriftsartikel (refereegranskat)abstract
- PROBLEM: The distribution and activation of mu-calpain and possible cleavage of integrin in human endometrial cells under hypoxic condition were investigated. METHOD OF STUDY: Human endometrial epithelial and stromal cells were subjected to hypoxia, and subsequently used for immunostaining and western blot analysis. RESULTS: The proform of mu-calpain was detected in the cytoplasm of normal cells, and displayed a substantial decrease after hypoxia. Conversely, the active form of mu-calpain was not detected in normal cells, but was abundant after hypoxia. The cytoplasmic domain of integrin beta3 was also detected in the cytoplasm of endometrial cells. Western blot analysis confirmed that both the proform of mu-calpain and the integrin beta3 cytoplasmic domain decreased during hypoxia. CONCLUSIONS: Mu-calpain is activated in human endometrial cells during hypoxia and that subsequent cleavage of the integrin beta3 cytoplasmic domain may give some adverse effects to the function of human endometrium.
|
|
| 7. |
- Badiola, N, et al.
(författare)
-
Induction of ER stress in response to oxygen-glucose deprivation of cortical cultures involves the activation of the PERK and IRE-1 pathways and of caspase-12.
- 2011
-
Ingår i: Cell death & disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 2
-
Tidskriftsartikel (refereegranskat)abstract
- Disturbance of calcium homeostasis and accumulation of misfolded proteins in the endoplasmic reticulum (ER) are considered contributory components of cell death after ischemia. However, the signal-transducing events that are activated by ER stress after cerebral ischemia are incompletely understood. In this study, we show that caspase-12 and the PERK and IRE pathways are activated following oxygen-glucose deprivation (OGD) of mixed cortical cultures or neonatal hypoxia-ischemia (HI). Activation of PERK led to a transient phosphorylation of eIF2α, an increase in ATF4 levels and the induction of gadd34 (a subunit of an eIF2α-directed phosphatase). Interestingly, the upregulation of ATF4 did not lead to an increase in the levels of CHOP. Additionally, IRE1 activation was mediated by the increase in the processed form of xbp1, which would be responsible for the observed expression of edem2 and the increased levels of the chaperones GRP78 and GRP94. We were also able to detect caspase-12 proteolysis after HI or OGD. Processing of procaspase-12 was mediated by NMDA receptor and calpain activation. Moreover, our data suggest that caspase-12 activation is independent of the unfolded protein response activated by ER stress.
|
|
| 8. |
- Barlind, Anna, 1978, et al.
(författare)
-
Decreased cytogenesis in the granule cell layer of the hippocampus and impaired place learning after irradiation of the young mouse brain evaluated using the IntelliCage platform.
- 2010
-
Ingår i: Experimental brain research. - : Springer Science and Business Media LLC. - 1432-1106 .- 0014-4819. ; 201:4, s. 781-787
-
Tidskriftsartikel (refereegranskat)abstract
- Radiation therapy is used to treat malignant tumors in the brain and central nervous system involvement of leukemia and lymphomas in children. However, ionizing radiation causes a number of adverse long-term side effects in the brain, including cognitive impairment. Hippocampal neurogenesis is important for place learning and has been shown to be decreased by irradiation (IR) in rats and mice. In the present study, 10-day-old male mice received 6-Gy IR to the brain on postnatal day 10. We used BrdU labeling of the granule cell layer (GCL) of the hippocampus to evaluate cell proliferation and survival. An unbiased, automated platform for monitoring of behavior in a group housing environment (IntelliCage) was used to evaluate place learning 2 months after IR. We show that cranial IR impaired place learning and reduced BrdU labeling by 50% in the GCL. Cranial IR also reduced whole body weight gain 5%. We conclude that this experimental paradigm provides a novel and time-saving model to detect differences in place learning in mice subjected to IR. This method of detecting behavioral differences can be used for further studies of adverse effects of IR on hippocampal neurogenesis and possible new strategies to ameliorate the negative effects of IR on cognition.
|
|
| 9. |
- Barlind, Anna, 1978, et al.
(författare)
-
The growth hormone secretagogue hexarelin increases cell proliferation in neurogenic regions of the mouse hippocampus.
- 2010
-
Ingår i: Growth hormone & IGF research. - : Elsevier BV. - 1532-2238 .- 1096-6374. ; 20:1, s. 49-54
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Radiation therapy (RT) to the brain is often used in the treatment of children with different types of malignant diseases affecting the brain. However, RT in childhood may also have severe side effects including impaired brain maturation and intellectual development. For childhood cancer survivors these adverse effects of RT can cause lifelong disability and suffering. Therefore, there is an unmet need to limit late effects after RT. Precursor cells in the subgranular zone of the dentate gyrus (DG) in the hippocampus are particularly sensitive to irradiation (IR). This may be of significance as newly generated neurons in the DG are important for memory and learning. GH secretagogues (GHS) have previously been shown to promote neurogenesis and to have neuroprotective effects. In addition, several parts of the brain, including the hippocampus, have been shown to express the GHS receptor 1a (GHS-R1a). The aim of this study was to evaluate the potential effect of the GHS hexarelin on proliferation and survival of progenitor cells in the hippocampus after brain IR in a mouse model. DESIGN: In the present study, 10-day-old male mice received 6Gy cranial IR. Non-irradiated sham animals were used as controls. We treated one group of irradiated and one sham group with hexarelin (100mug/kg/day) for 28days and used immunohistochemical labeling of bromo-deoxy uridine (BrdU) and phospho-histone H3 of the granular cell layer of the DG to evaluate proliferation and cell survival after IR at postnatal day ten. RESULTS: Our results show that hexarelin significantly increased the number of BrdU-positive cells in the granule cell layer by approximately 50% compared to controls. CONCLUSION: The increased number of BrdU-positive cells in the granule cell layer suggests a partial restoration in the pool of proliferating cells by hexarelin after IR.
|
|
| 10. |
|
|
| 11. |
- Bi, D., et al.
(författare)
-
The association between sex-related interleukin-6 gene polymorphisms and the risk for cerebral palsy
- 2014
-
Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The relationship between genetic factors and the development of cerebral palsy (CP) has recently attracted much attention. Polymorphisms in the genes encoding proinflammatory cytokines have been shown to be associated with susceptibility to perinatal brain injury and development of CP. Interleukin-6 (IL-6) is a proinflammatory cytokine that plays a pivotal role in neonatal brain injury, but conflicting results have been reported regarding the association between IL-6 single nucleotide polymorphisms (SNPs) and CP. The purpose of this study was to analyze IL-6 gene polymorphisms and protein expression and to explore the role of IL-6 in the Chinese CP population. Methods: A total of 753 healthy controls and 713 CP patients were studied to detect the presence of five SNPs (rs1800796, rs2069837, rs2066992, rs2069840, and rs10242595) in the IL-6 locus. Of these, 77 healthy controls and 87 CP patients were selected for measurement of plasma IL-6 by Luminex assay. The SHEsis program was used to analyze the genotyping data. For all comparisons; multiple testing on each individual SNP was corrected by the SNPSpD program. Results: There were no differences in allele or genotype frequencies between the overall CP patients and controls among the five genetic polymorphisms. However, subgroup analysis found significant sex-related differences in allele and genotype frequencies. Differences were found between spastic CP and controls in males for rs2069837; between CP with periventricular leukomalacia and controls in males for rs1800796 and rs2066992; and between term CP and controls in males for rs2069837. Plasma IL-6 levels were higher in CP patients than in the controls, and this difference was more robust in full-term male spastic CP patients. Furthermore, the genotype has an effect on IL-6 synthesis. Conclusions: The influence of IL-6 gene polymorphisms on IL-6 synthesis and the susceptibility to CP is related to sex and gestational age.
|
|
| 12. |
|
|
| 13. |
- Blomgren, Klas, 1963, et al.
(författare)
-
Free radicals, mitochondria, and hypoxia-ischemia in the developing brain
- 2006
-
Ingår i: Free Radic Biol Med. ; 40:3, s. 388-97
-
Forskningsöversikt (refereegranskat)abstract
- The immature brain is particularly susceptible to free radical injury because of its poorly developed scavenging systems and high availability of iron for the catalytic formation of free radicals. Neurons are more vulnerable to free radical damage than glial cells, but oligodendrocyte progenitors and immature oligodendrocytes in very prematurely born infants are selectively vulnerable to depletion of antioxidants and free radical attack. Reactive oxygen and nitrogen species play important roles in the initiation of apoptotic mechanisms and in mitochondrial permeability transition, and therefore constitute important targets for therapeutic intervention. Oxidative stress is an early feature after cerebral ischemia and experimental studies targeting the formation of free radicals demonstrate various degrees of protection after perinatal insults. Oxidative stress-regulated release of proapoptotic factors from mitochondria appears to play a much more important role in the immature brain. This review will summarize and compare with the adult brain some of the current knowledge of free radical formation in the developing brain and its roles in the pathophysiology after cerebral hypoxia-ischemia.
|
|
| 14. |
- Blomgren, Klas, 1963, et al.
(författare)
-
Injury and repair in the immature brain.
- 2013
-
Ingår i: Translational stroke research. - : Springer Science and Business Media LLC. - 1868-601X .- 1868-4483. ; 4:2, s. 135-136
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 15. |
|
|
| 16. |
- Blomgren, Klas, 1963, et al.
(författare)
-
Pathological apoptosis in the developing brain
- 2007
-
Ingår i: Apoptosis. - : Springer Science and Business Media LLC. - 1360-8185 .- 1573-675X. ; 12:5, s. 993-1010
-
Forskningsöversikt (refereegranskat)abstract
- More than half of the initially-formed neurons are deleted in certain brain regions during normal development. This process, whereby cells are discretely removed without interfering with the further development of remaining cells, is called programmed cell death (PCD). The term apoptosis is used to describe certain morphological manifestations of PCD. Many of the effectors of this developmental cell death program are highly expressed in the developing brain, making it more susceptible to accidental activation of the death machinery, e.g. following hypoxia-ischemia or irradiation. Recent evidence suggests, however, that activation and regulation of cell death mechanisms under pathological conditions do not exactly mirror physiological, developmentally regulated PCD. It may be argued that the conditions after e.g. ischemia are not even compatible with the execution of PCD as we know it. Under pathological conditions cells are exposed to various stressors, including energy failure, oxidative stress and unbalanced ion fluxes. This results in parallel triggering and potential overshooting of several different cell death pathways, which then interact with one another and result in complex patterns of biochemical manifestations and cellular morphological features. These types of cell death are here called "pathological apoptosis," where classical hallmarks of PCD, like pyknosis, nuclear condensation and caspase-3 activation, are combined with non-PCD features of cell death. Here we review our current knowledge of the mechanisms involved, with special focus on the potential for therapeutic intervention tailored to the needs of the developing brain.
|
|
| 17. |
- Blomstrand, Malin, 1974, et al.
(författare)
-
Different reactions to irradiation in the juvenile and adult hippocampus
- 2014
-
Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 90:9, s. 807-815
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: Cranial radiotherapy is an important tool in the cure of primary brain tumors. Unfortunately, it is associated with late-appearing toxicity to the normal brain tissue, including cognitive impairment, particularly in children. The underlying mechanisms are not fully understood but involve changes in hippocampal neurogenesis. Recent studies report essentially different responses in the juvenile and the adult brain after irradiation, but this has never been verified in a comparative study. Materials and methods: We subjected juvenile (9-day-old) and adult (6-month-old) male rats to a single dose of 6 Gray (Gy) whole brain irradiation and euthanized them 6 hours, 7 days or 4 weeks later. Hippocampal lysates were analyzed for caspase-3 activity (apoptosis) and the expression of cytokines, chemokines and growth factors. Four weeks after irradiation, the number of microglia (expressing ionized calcium-binding adapter molecule 1, Iba-1), activated microglia (expressing cluster of differentiation 68 [CD68]), bromodeoxyuridine (BrdU) incorporation and granule cell layer (GCL) volume were assessed. Results: The major findings were (i) higher baseline BrdU incorporation (cell proliferation) in juvenile than in adult controls, which explains the increased susceptibility to irradiation and higher level of acute cell death (caspase activity) in juvenile rats, leading to impaired growth and subsequently a smaller dentate gyrus volume 4 weeks after irradiation, (ii) more activated (CD68-positive) microglia in adult compared to juvenile rats, regardless of irradiation, and (iii) differently expressed cytokines and chemokines after cranial irradiation in the juvenile compared to the adult rat hippocampus, indicating a more pro-inflammatory response in adult brains. Conclusion: We found essentially diverse irradiation reactions in the juvenile compared to the adult hippocampus, indicating different mechanisms involved in degeneration and regeneration after injury. Strategies to ameliorate the cognitive deficits after cranial radiotherapy should therefore likely be adapted to the developmental level of the brain.
|
|
| 18. |
- Blomstrand, Malin, et al.
(författare)
-
Estimated clinical benefit of protecting neurogenesis in the developing brain during radiation therapy for pediatric medulloblastoma.
- 2012
-
Ingår i: Neuro-Oncology. - : Oxford University Press (OUP). - 1523-5866 .- 1522-8517. ; 14:7, s. 882-889
-
Tidskriftsartikel (refereegranskat)abstract
- We sought to assess the feasibility and estimate the benefit of sparing the neurogenic niches when irradiating the brain of pediatric patients with medulloblastoma (MB) based on clinical outcome data. Pediatric MB survivors experience a high risk of neurocognitive adverse effects, often attributed to the whole-brain irradiation that is part of standard management. Neurogenesis is very sensitive to radiation, and limiting the radiation dose to the hippocampus and the subventricular zone (SVZ) may preserve neurocognitive function. Radiotherapy plans were created using 4 techniques: standard opposing fields, intensity-modulated radiotherapy (IMRT), intensity-modulated arc therapy (IMAT), and intensity-modulated proton therapy (IMPT). Mean dose to the hippocampus and SVZ (mean for both sites) could be limited to 88.3% (range, 83.6%-91.0%), 77.1% (range, 71.5%-81.3%), and 42.3% (range, 26.6%-51.2%) with IMAT, IMRT, and IMPT, respectively, while maintaining at least 95% of the prescribed dose in 95% of the whole-brain target volume. Estimated risks for developing memory impairment after a prescribed dose of 23.4 Gy were 47% (95% confidence interval [CI], 21%-69%), 44% (95% CI, 21%-65%), 41% (95% CI, 22%-60%), and 33% (95% CI, 23%-44%) with opposing fields, IMAT, IMRT, and IMPT, respectively. Neurogenic niche sparing during cranial irradiation of pediatric patients with MB is feasible and is estimated to lower the risks of long-term neurocognitive sequelae. Greatest sparing is achieved with intensity-modulated proton therapy, thus making this an attractive option to be tested in a prospective clinical trial.
|
|
| 19. |
- Boström, Martina, et al.
(författare)
-
A role for endothelial cells in radiation-induced inflammation
- 2018
-
Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 94:3, s. 259-271
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To unravel the role of the vasculature in radiation-induced brain tissue damage.Materials and methods: Postnatal day 14 mice received a single dose of 10Gy cranial irradiation and were sacrificed 6h, 24h or 7 days post-irradiation. Endothelial cells were isolated from the hippocampus and cerebellum using fluorescence-activated cell sorting, followed by cell cycle analysis and gene expression profiling.Results: Flow cytometric analysis revealed that irradiation increased the percentage of endothelial cells, relative to the whole cell population in both the hippocampus and the cerebellum. This change in cell distribution indicates that other cell types are more susceptible to irradiation-induced cell death, compared to endothelial cells. This was supported by data showing that genes involved in endothelial cell-specific apoptosis (e.g. Smpd1) were not induced at any time point investigated but that genes involved in cell-cycle arrest (e.g. Cdkn1a) were upregulated at all investigated time points, indicating endothelial cell repair. Inflammation-related genes, on the other hand, were strongly induced, such as Ccl2, Ccl11 and Il6.Conclusions: We conclude that endothelial cells are relatively resistant to ionizing radiation but that they play an active, hitherto unknown, role in the inflammatory response after irradiation. In the current study, this was shown in both the hippocampus, where neurogenesis and extensive cell death after irradiation occurs, and in the cerebellum, where neurogenesis no longer occurs at this developmental age.
|
|
| 20. |
- Boström, Martina, et al.
(författare)
-
Irradiation to the young mouse brain caused long-term, progressive depletion of neurogenesis but did not disrupt the neurovascular niche
- 2013
-
Ingår i: Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016. ; 33:6, s. 935-943
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the effects of ionizing radiation on microvessel structure and complexity in the hippocampus. We also assessed neurogenesis and the neurovascular niche. Postnatal day 14 male C57BL/6 mice received a single dose of 8Gy to the whole brain and were killed 6 hours, 1 week, 7 weeks, or 1 year later. Irradiation decreased the total number of microvessels and branching points from 1 week onwards and decreased the total microvessel area 1 and 7 weeks after irradiation. After an initial increase in vascular parameter densities, concomitant with reduced growth of the hippocampus, the densities normalized with time, presumably adapting to the needs of the surrounding nonvascular tissue. Irradiation decreased the number of neural stem and progenitor cells in the hippocampus. The relative loss increased with time, resulting in almost completely ablated neurogenesis (DCX(+) cells) 1 year after irradiation (77% decreased 1 week, 86% decreased 7 weeks, and 98% decreased 1 year after irradiation compared with controls). After irradiation, the distance between undifferentiated stem cells and microvessels was unaffected, and very few dying endothelial cells were detected. Taken together, these results indicate that the vasculature adjusts to the surrounding neural and glial tissue after irradiation, not vice-versa.Journal of Cerebral Blood Flow & Metabolism advance online publication, 13 March 2013; doi:10.1038/jcbfm.2013.34.
|
|
| 21. |
- Boström, Martina, et al.
(författare)
-
The hippocampal neurovascular niche during normal development and after irradiation to the juvenile mouse brain.
- 2014
-
Ingår i: International journal of radiation biology. - : Informa UK Limited. - 1362-3095 .- 0955-3002. ; 90:9, s. 778-89
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate the effects of cranial irradiation on the neurovascular niche in the young brain. Disruption of this niche has previously been observed in the adult rat brain after irradiation.We subjected postnatal day 14 (P14) mice to a single dose of 8 Gy whole brain irradiation and measured the distance between microvessels and either neural progenitor cells (doublecortin-positive, DCX(+)) or proliferating cells (Ki-67(+)) in the dorsal hippocampal subgranular zone (SGZ) 6 hours, 1 week and 7 weeks post-irradiation. In addition, pericyte coverage of microvessels in the SGZ was measured.DCX(+) and Ki-67(+) cells were located closer to microvessels in the adult brain compared to young, still growing brains, constituting new information on normal development. We found an increased distance between microvessels and DCX(+) cells 6 h post-irradiation and between microvessels and Ki-67(+) cells 1 week post-irradiation. Furthermore, pericyte coverage was transiently decreased by 17% 6 h post-irradiation.The hippocampal neurovascular niche in the young, growing brain is transiently disrupted by irradiation. It remains to be elucidated what role these transient changes play in the apparently permanent ablation of hippocampal neurogenesis previously demonstrated in the same model.
|
|
| 22. |
- Culmsee, C., et al.
(författare)
-
Apoptosis-inducing factor triggered by poly(ADP-ribose) polymerase and Bid mediates neuronal cell death after oxygen-glucose deprivation and focal cerebral ischemia
- 2005
-
Ingår i: J Neurosci. ; 25:44, s. 10262-72
-
Tidskriftsartikel (refereegranskat)abstract
- Delayed neuronal cell death occurring hours after reperfusion is a hallmark of ischemic stroke and a primary target for neuroprotective strategies. In the present study, we investigated whether apoptosis-inducing factor (AIF), a caspase-independent proapoptotic protein, is responsible for neuronal cell death after glutamate toxicity and oxygen-glucose deprivation (OGD) in vitro and after experimental stroke in vivo. AIF translocated to the nucleus in which it colocalized with DNA fragmentation and nuclear apoptotic morphology after exposure to glutamate or OGD in cultured neurons or after transient middle cerebral artery occlusion (MCAo) in mice. Small inhibitory RNA-mediated downregulation of AIF reduced glutamate- and OGD-induced neuronal apoptosis by 37 and 60%, respectively (p < 0.01). Moreover, Harlequin mutant mice, which express AIF at low levels (approximately 20% of wild-type mice), displayed smaller infarct volumes (-43%; p < 0.03) and showed dramatically reduced cell death in the ischemic penumbra after 45 min of MCAo compared with wild-type littermates. Inhibition of poly(ADP-ribose) polymerase and Bid reduced nuclear AIF translocation. These results provide the first evidence for a causal role of AIF in ischemic neuronal cell death. Therefore, caspase-independent cell death signaling may provide a promising novel target for therapeutic interventions in cerebrovascular diseases.
|
|
| 23. |
- Dobsicek Trefna, Hana, 1979, et al.
(författare)
-
Antenna Applicator for Microwave Hyperthermia Treatment of Pediatric Brain Cancer
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 9788890701849
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A novel antenna applicator for microwave hyperthermia allowing treatment of deep brain tumors is proposed. The applicator consists of up to 16 antennas placed around the head in a helmet-like set-up and operates at a frequency range of 430-1000~MHz. The self-grounded bow-tie antennas are housed in a molded plastic enclosure with the shape of a truncated cone. The inner space of the enclosure is filled with distilled water. The antennas are attached to a perimetric water bolus with a thickness of 2 cm and aligned with the head shape. The focusing ability of the applicator was investigated on a homogeneous SAM model and on a model of a 13-year old patient containing a spherical tumor of 2 cm radius. Two different tumor positions were investigated: the right frontal lobe and the central brain. The obtained SAR distributions are favorable, although a relatively high level of energy is also absorbed on the surface of the body. This heating is however not expected to cause problems as it can be cooled by blood perfusion and water bolus. Our results show that focused microwave heating in the brain is feasible and warrants further verification on phantoms.
|
|
| 24. |
|
|
| 25. |
- Fukuda, A., et al.
(författare)
-
Age-dependent sensitivity of the developing brain to irradiation is correlated with the number and vulnerability of progenitor cells
- 2005
-
Ingår i: J Neurochem. ; 92:3, s. 569-84
-
Tidskriftsartikel (refereegranskat)abstract
- In a newly established model of unilateral, irradiation (IR)-induced injury we compared the outcome after IR to the immature and juvenile brain, using rats at postnatal days 9 or 23, respectively. We demonstrate that (i) the immature brains contained more progenitors in the subventricular zone (SVZ) and subgranular zone (SGZ) compared with the juvenile brains; (ii) cellular injury, as judged by activation of caspase 3 and p53, as well as nitrotyrosine formation, was more pronounced in the SVZ and SGZ in the immature brains 6 h after IR; (iii) the number of progenitor and immature cells in the SVZ and SGZ decreased 6 h and 7 days post-IR, corresponding to acute and subacute effects in humans, respectively, these effects were more pronounced in immature brains; (iv) myelination was impaired after IR at both ages, and much more pronounced after IR to immature brains; (v) the IR-induced changes remained significant for at least 10 weeks, corresponding to late effects in humans, and were most pronounced after IR to immature brains. It appears that IR induces both an acute loss of progenitors through apoptosis and a perturbed microenvironment incompatible with normal proliferation and differentiation, and that this is more pronounced in the immature brain.
|
|
| 26. |
- Fukuda, Aya, et al.
(författare)
-
Progenitor cell injury after irradiation to the developing brain can be modulated by mild hypothermia or hyperthermia
- 2005
-
Ingår i: J Neurochem. ; 94:6, s. 1604-19
-
Tidskriftsartikel (refereegranskat)abstract
- Ionizing radiation induced acute cell death in the dentate gyrus subgranular zone (SGZ) and the subventricular zone (SVZ). Hypomyelination was also observed. The effects of mild hypothermia and hyperthermia for 4 h after irradiation (IR) were studied in postnatal day 9 rats. One hemisphere was irradiated with a single dose of 8 Gy and animals were randomized to normothermia (rectal temperature 36 degrees C for 4 h), hypothermia (32 degrees C for 4 h) or hyperthermia (39 degrees C for 4 h). Cellular injury, e.g. chromatin condensation and nitrotyrosine formation, appeared to proceed faster when the body temperature was higher. Caspase-3 activation was more pronounced in the hyperthermia group and nuclear translocation of p53 was less pronounced in the hypothermia group 6 h after IR. In the SVZ the loss of nestin-positive progenitors was more pronounced (48%) and the size was smaller (45%) in the hyperthermia group 7 days post-IR. Myelination was not different after hypo- or hyperthermia. This is the first report to demonstrate that hypothermia may be beneficial and that hyperthermia may aggravate the adverse side-effects after radiation therapy to the developing brain.
|
|
| 27. |
- Fukuda, Hirotsugu, et al.
(författare)
-
Irradiation-induced progenitor cell death in the developing brain is resistant to erythropoietin treatment and caspase inhibition
- 2004
-
Ingår i: Cell Death Differ. - Univ Gothenburg, Dept Physiol, Perinatal Ctr, SE-40530 Gothenburg, Sweden. Osaka Univ, Sch Med, Dept Obstet & Gynecol, Suita, Osaka 5650871, Japan. Zhengzhou Univ, Affiliated Hosp 3, Dept Pediat, Zhengzhou 450052, Peoples R China. Uppsala Univ, Dept Neurosci, SE-75123 Uppsala, Sweden. Sahlgrens Univ Hosp, Dept Radiat Phys, SE-41345 Gothenburg, Sweden. H Lundbeck & Co AS, Mol Dis Biol, DK-2500 Copenhagen, Denmark. Sahlgrens Univ Hosp, Dept Oncol, SE-41345 Gothenburg, Sweden. Queen Silvia Childrens Hosp, Dept Pediat, SE-41685 Gothenburg, Sweden. : NATURE PUBLISHING GROUP. - 1350-9047 .- 1476-5403. ; 11:11, s. 1166-78
-
Tidskriftsartikel (refereegranskat)abstract
- One hemisphere of postnatal day 8 (P8) rats or P10 mice was irradiated with a single dose of 4-12 Gy, and animals were killed from 2 h to 8 weeks after irradiation (IR). In the subventricular zone (SVZ) and the granular cell layer (GCL) of the dentate gyrus, harboring neural and other progenitor cells, nitrosylation and p53 peaked 2-12 h after IR, followed by markers for active caspase-3, apoptosis-inducing factor and TUNEL (6-24 h). Ki67-positive (proliferating) cells had disappeared by 12 h and partly reappeared by 7 days post-IR. The SVZ and GCL areas decreased approximately 50% 7 days after IR. The development of white matter was hampered, resulting in 50-70% less myelin basic protein staining. Pretreatment with erythropoietin did not confer protection against IR. Caspase inhibition by overexpression of XIAP prevented caspase-9 and caspase-3 activation but not cell death, presumably because of increased caspase-independent cell death.
|
|
| 28. |
- Galluzzi, L, et al.
(författare)
-
Guidelines for the use and interpretation of assays for monitoring cell death in higher eukaryotes.
- 2009
-
Ingår i: Cell death and differentiation. - : Springer Science and Business Media LLC. - 1476-5403 .- 1350-9047. ; 16:8, s. 1093-107
-
Forskningsöversikt (refereegranskat)abstract
- Cell death is essential for a plethora of physiological processes, and its deregulation characterizes numerous human diseases. Thus, the in-depth investigation of cell death and its mechanisms constitutes a formidable challenge for fundamental and applied biomedical research, and has tremendous implications for the development of novel therapeutic strategies. It is, therefore, of utmost importance to standardize the experimental procedures that identify dying and dead cells in cell cultures and/or in tissues, from model organisms and/or humans, in healthy and/or pathological scenarios. Thus far, dozens of methods have been proposed to quantify cell death-related parameters. However, no guidelines exist regarding their use and interpretation, and nobody has thoroughly annotated the experimental settings for which each of these techniques is most appropriate. Here, we provide a nonexhaustive comparison of methods to detect cell death with apoptotic or nonapoptotic morphologies, their advantages and pitfalls. These guidelines are intended for investigators who study cell death, as well as for reviewers who need to constructively critique scientific reports that deal with cellular demise. Given the difficulties in determining the exact number of cells that have passed the point-of-no-return of the signaling cascades leading to cell death, we emphasize the importance of performing multiple, methodologically unrelated assays to quantify dying and dead cells.
|
|
| 29. |
- Galluzzi, Lorenzo, et al.
(författare)
-
Mitochondrial membrane permeabilization in neuronal injury.
- 2009
-
Ingår i: Nature reviews. Neuroscience. - : Springer Science and Business Media LLC. - 1471-0048 .- 1471-003X. ; 10:7, s. 481-94
-
Forskningsöversikt (refereegranskat)abstract
- Acute neurological conditions such as cerebrovascular diseases and trauma are associated with irreversible loss of neurons and glial cells. Severe or prolonged injury results in uncontrollable cell death within the core of lesions. Conversely, cells that are less severely damaged succumb in a relatively slow fashion, frequently via the intrinsic pathway of cell death, through the deterioration of mitochondrial functions. The permeabilization of mitochondrial membranes determines whether cells will succumb to or survive the injury, and represents a 'point of no return' in mitochondrial cell death. It is therefore an attractive target for the development of new neuroprotective interventions.
|
|
| 30. |
- Ghaderi Aram, Morteza, 1988, et al.
(författare)
-
Radiobiological modeling of hyperthermia combined with Gamma-Knife radiosurgery in pediatric brain cancer
- 2021
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Assessment of the synergistic effect of radiotherapy (RT) and hyperthermia (HT) in clinical settings is crucial for further expansion of hyperthermia. The radiobiological modeling using an extended version of the LQ model with temperature-dependent radiosensitivity parameters has been suggested in combination with external beam radiotherapy in previous studies. This study investigates the radiobiological effect of intracranial hyperthermia combined with stereotactic radiosurgery (SRS) in pediatric brain cancers. The hyperthermia treatment plan was achieved with an elliptical applicator consisting of 16 ORWG antennas working at 400 MHz and a hybrid Specific Absorption Rate (SAR) optimization procedure based on Time-Reversal and PSO. The radiotherapy plan was created by the treatment planning software of Leksell Gamma Knife® Icon™.
|
|
| 31. |
- Ghezzi, Pietro, et al.
(författare)
-
Erythropoietin: not just about erythropoiesis
- 2010
-
Ingår i: LANCET. - 0140-6736. ; 375:9732, s. 2142-2142
-
Tidskriftsartikel (refereegranskat)abstract
- Referred to by Department of Error, The Lancet, Volume 376, Issue 9739, 7–13 August 2010, Page 418
|
|
| 32. |
- Hallin, Ulrika, 1971, et al.
(författare)
-
Bcl-2 phosphorylation in the BH4 domain precedes caspase-3 activation and cell death after neonatal cerebral hypoxic-ischemic injury
- 2006
-
Ingår i: Neurobiol Dis. ; 21:3, s. 478-86
-
Tidskriftsartikel (refereegranskat)abstract
- To date, there are very few in vivo studies addressing the role of Bcl-2 phosphorylation. In a model of neonatal hypoxic-ischemic (HI) brain injury, we characterized the spatial and temporal phosphorylation of Bcl-2 at serine-24 (PS24-Bcl-2), using a site-specific antibody. Very few cells positive for PS24-Bcl-2 were found in control animals, but the number increased during reperfusion in all investigated brain areas in the ipsilateral hemisphere after HI, particularly in the border region between intact and damaged tissue. The highest numbers were encountered 24 h post-HI. Phosphorylation of Bcl-2 at serine-24 coincided with cytochrome c release after hypoxia-ischemia and preceded caspase-3 activation. Injured neurons displayed a predominantly nuclear, but also mitochondrial, localization of PS24-Bcl-2 immunoreactivity. In conclusion, phosphorylation of Bcl-2 at serine 24 was induced by hypoxia-ischemia, presumably resulting in loss of its anti-apoptotic function.
|
|
| 33. |
- Han, Wei, et al.
(författare)
-
Delayed, Long-Term Administration of the Caspase Inhibitor Q-VD-OPh Reduced Brain Injury Induced by Neonatal Hypoxia-Ischemia.
- 2014
-
Ingår i: Developmental neuroscience. - : S. Karger AG. - 1421-9859 .- 0378-5866. ; 36:1, s. 64-72
-
Tidskriftsartikel (refereegranskat)abstract
- Apoptosis contributes greatly to the morphological and biochemical features of cell death after neonatal cerebral hypoxia-ischemia (HI), making this mode of cell death a promising therapeutic target. We previously showed that 10 mg/kg of the caspase inhibitor Q-VD-OPh at the onset of and immediately after HI on postnatal day 9 reduced brain infarct volume. In this study, delayed administration of Q-VD-OPh, 12 and 36 h after HI, decreased HI-induced caspase-3 activity (DEVD cleavage) by 23% and diminished the levels of the proinflammatory chemokines CCL2 (MCP-1) and CCL3 (MIP-1α) by 29.3 and 29.1%, respectively, but not the levels of the anti-inflammatory cytokines IL-4 and IL-10. Long-term administration of Q-VD-OPh initiated at 12 h after HI, and continued at 24-hour intervals for 2 weeks, reduced total brain tissue loss by 31.3% from 41.5 ± 3.1 mm(3) in the vehicle group to 28.5 ± 3.0 mm(3) in the Q-VD-OPh group when evaluated 16 weeks after HI (p = 0.004). Q-VD-OPh treatment also ameliorated the loss of sensorimotor function, as evaluated by a cylinder rearing test (Q-VD-OPh: 30.8 ± 4.3% vs. vehicle: 59.7 ± 6.3% in nonimpaired forepaw preference) 3 weeks after HI, and reduced HI-induced hyperactivity, as measured in an open field test (Q-VD-OPh: 4,062 ± 198 cm vs. vehicle: 4,792 ± 205 cm in distance moved) 7 weeks after the insult. However, the functional protection was no longer observed when analyzed again at later time points. The mechanisms underlying the discrepancy between sustained morphological protection and transient functional protection remain to be elucidated. © 2014 S. Karger AG, Basel.
|
|
| 34. |
- Hangen, E, et al.
(författare)
-
A brain-specific isoform of mitochondrial apoptosis-inducing factor: AIF2.
- 2010
-
Ingår i: Cell death and differentiation. - : Springer Science and Business Media LLC. - 1476-5403 .- 1350-9047. ; 17:7, s. 1155-66
-
Tidskriftsartikel (refereegranskat)abstract
- Apoptosis-inducing factor (AIF) has important supportive as well as potentially lethal roles in neurons. Under normal physiological conditions, AIF is a vital redox-active mitochondrial enzyme, whereas in pathological situations, it translocates from mitochondria to the nuclei of injured neurons and mediates apoptotic chromatin condensation and cell death. In this study, we reveal the existence of a brain-specific isoform of AIF, AIF2, whose expression increases as neuronal precursor cells differentiate. AIF2 arises from the utilization of the alternative exon 2b, yet uses the same remaining 15 exons as the ubiquitous AIF1 isoform. AIF1 and AIF2 are similarly imported to mitochondria in which they anchor to the inner membrane facing the intermembrane space. However, the mitochondrial inner membrane sorting signal encoded in the exon 2b of AIF2 is more hydrophobic than that of AIF1, indicating a stronger membrane anchorage of AIF2 than AIF1. AIF2 is more difficult to be desorbed from mitochondria than AIF1 on exposure to non-ionic detergents or basic pH. Furthermore, AIF2 dimerizes with AIF1, thereby preventing its release from mitochondria. Conversely, it is conceivable that a neuron-specific AIF isoform, AIF2, may have been 'designed' to be retained in mitochondria and to minimize its potential neurotoxic activity.Cell Death and Differentiation advance online publication, 29 January 2010; doi:10.1038/cdd.2009.211.
|
|
| 35. |
- Hangen, Emilie, et al.
(författare)
-
Interaction between AIF and CHCHD4 Regulates Respiratory Chain Biogenesis
- 2015
-
Ingår i: Molecular cell. - : Elsevier BV. - 1097-4164 .- 1097-2765. ; 58:6, s. 1001-1014
-
Tidskriftsartikel (refereegranskat)abstract
- Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein that, beyond its apoptotic function, is required for the normal expression of major respiratory chain complexes. Here we identified an AIF-interacting protein, CHCHD4, which is the central component of a redox-sensitive mitochondrial intermembrane space import machinery. Depletion or hypomorphic mutation of AIF caused a downregulation of CHCHD4 protein by diminishing its mitochondrial import. CHCHD4 depletion sufficed to induce a respiratory defect that mimicked that observed in AIF-deficient cells. CHCHD4 levels could be restored in AIF-deficient cells by enforcing its AIF-independent mitochondrial localization. This modified CHCHD4 protein reestablished respiratory function in AIF-deficient cells and enabled AIF-deficient embryoid bodies to undergo cavitation, a process of programmed cell death required for embryonic morphogenesis. These findings explain how AIF contributes to the biogenesis of respiratory chain complexes, and they establish an unexpected link between the vital function of AIF and the propensity of cells to undergo apoptosis.
|
|
| 36. |
- Hangen, Emilie, et al.
(författare)
-
Life with or without AIF.
- 2010
-
Ingår i: Trends in biochemical sciences. - : Elsevier BV. - 0968-0004. ; 35:5, s. 278-87
-
Forskningsöversikt (refereegranskat)abstract
- Apoptosis-inducing factor (AIF) was initially discovered as a caspase-independent death effector. AIF fulfills its lethal function after its release from mitochondria and its translocation to the nucleus of the dying cell. The contribution of AIF to programmed cell death is dependent upon the cell type and apoptotic insult. Recent in vivo data indicate that, in addition to its lethal activity, AIF plays a vital mitochondrial role in healthy cells. A segment of AIF which is dispensable for its apoptotic function carries an NADH-oxidase domain that regulates the respiratory chain complex I and is required for cell survival, proliferation and mitochondrial integrity. Mice that express reduced levels of AIF constitute a reliable model of complex I deficiency. Here we discuss recent reports on the survival-related function(s) of AIF.
|
|
| 37. |
- Hellström, Nina, 1976, et al.
(författare)
-
Differential recovery of neural stem cells in the subventricular zone and dentate gyrus after ionizing radiation.
- 2009
-
Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 27:3, s. 634-641
-
Tidskriftsartikel (refereegranskat)abstract
- Radiation therapy is a widely used treatment for malignant CNS tumors. Mature neurons are terminally differentiated, whereas stem and progenitor cells have a prominent proliferative capacity and are therefore highly vulnerable to irradiation. Our aim was to investigate how cranial radiation in young rats would affect stem/progenitor cells in the two niches of adult neurogenesis, the subventricular zone (SVZ) and the dentate gyrus of the hippocampal formation. Nine weeks after irradiation we found that in irradiated animals, hippocampal neurogenesis was reduced to 5% of control levels. Similarly, the number of actively proliferating cells and radial glia-like stem cells (nestin+/GFAP+) in the dentate gyrus, was reduced to 10% and 15% of control levels, respectively. In the irradiated olfactory bulb, neurogenesis was reduced to 40% of control levels and the number of actively proliferating cells in the SVZ was reduced to 53% of control levels. However, the number of nestin+/GFAP+ cells in the SVZ was unchanged compared to controls. To evaluate the immediate response to the radiation injury we quantified the amount of proliferation in the SVZ and dentate gyrus one day after irradiation. We found an equal reduction in proliferating cells both in dentate gyrus and SVZ. In summary, we show an initial response to radiation injury that is similar in both brain stem cell niches. However, the long-term effects on stem cells and neurogenesis in these two areas differ significantly, where the dentate gyrus is severely affected long-term, whereas the SVZ appears to recover with time. ______________________________________________________________________________
|
|
| 38. |
- Hellström, Nina, 1976, et al.
(författare)
-
Unique gene expression patterns indicate microglial contribution to neural stem cell recovery following irradiation.
- 2011
-
Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 46:4, s. 710-9
-
Tidskriftsartikel (refereegranskat)abstract
- Ionizing radiation results in damage to neural stem cells and reduced neurogenesis. The aim of the present study was to determine intrinsic and extrinsic factors that influence neural stem cell survival following irradiation, using qPCR. Gene expression of hippocampal and SVZ neurospheres were analyzed following irradiation, and results demonstrated that irradiated hippocampal and SVZ stem cells displayed similar gene expression profiles for intrinsic genes. Irradiated microglia (extrinsic factor) isolated from the SVZ exhibited increased gene expression of growth factors involved in stem cell maintenance, proliferation, and survival. However, microglial genes in the irradiated hippocampus responded less favorably with respect to stem cell recovery. This might explain the superior recovery of SVZ compared to hippocampal stem cells following in vivo irradiation. In addition, our results show that a combination of growth factors, which were upregulated in SVZ microglia, increased the proliferation and decreased cell death of irradiated neurospheres in vitro.
|
|
| 39. |
- Huo, Kaiming, et al.
(författare)
-
Lithium reduced neural progenitor apoptosis in the hippocampus and ameliorated functional deficits after irradiation to the immature mouse brain.
- 2012
-
Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 51:1-2, s. 32-42
-
Tidskriftsartikel (refereegranskat)abstract
- Lithium was recently shown to inhibit apoptosis and promote survival of neural progenitor cells after hypoxia-ischemia in the immature rat brain. Our aim was to evaluate the effects of lithium on cell death and proliferation in the hippocampus after irradiation (IR) to the immature brain. Male mice were injected with 2 mmol/kg lithium chloride i.p. on postnatal day 9 (P9) and additional lithium injections, 1 mmol/kg, were administered at 24 h intervals for up to 7 days. BrdU was injected 4 h after lithium injections on P9 and P10. The left hemisphere received a single dose of 8 Gy (MV photons) on P11. The animals were euthanized 6 h or 7 weeks after IR. The number of BrdU-labeled cells in the subgranular zone (SGZ) of the granule cell layer (GCL) 6h after IR was 24% higher in the lithium-treated mice. The number of proliferating, phospho-histone H3-positive cells in the SGZ 7 weeks after IR was 59% higher in the lithium group, so the effect was long-lasting. The number of apoptotic cells in the SGZ 6 h after IR was lower in the lithium group, as judged by 3 different parameters, pyknosis, staining for active caspase-3 and TUNEL. Newly formed cells (BrdU-labeled 1 or 2 days before IR) showed the greatest degree of protection, as judged by 50% fewer TUNEL-positive cells, whereas non-BrdU-labeled cells showed 38% fewer TUNEL-positive cells 6 h after IR. Consequently, the growth retardation of the GCL was less pronounced in the lithium group. The number and size of microglia in the DG were also lower in the lithium group, indicating reduced inflammation. Learning was facilitated after lithium treatment, as judged by improved context-dependent fear conditioning, and improved place learning, as judged by assessment in the IntelliCage platform. In summary, lithium administration could decrease IR-induced neural progenitor cell apoptosis in the GCL of the hippocampus and ameliorate learning impairments. It remains to be shown if lithium can be used to prevent the debilitating cognitive late effects seen in children treated with cranial radiotherapy.
|
|
| 40. |
- Johansson, Inger, 1962, et al.
(författare)
-
Proliferative and protective effects of growth hormone secretagogues on adult rat hippocampal progenitor cells.
- 2008
-
Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 149:5, s. 2191-9
-
Tidskriftsartikel (refereegranskat)abstract
- Progenitor cells in the subgranular zone of the hippocampus may be of significance for functional recovery after various injuries because they have a regenerative potential to form new neuronal cells. The hippocampus has been shown to express the GH secretagogue (GHS) receptor 1a, and recent studies suggest GHS to both promote neurogenesis and have neuroprotective effects. The aim of the present study was to investigate whether GHS could stimulate cellular proliferation and exert cell protective effects in adult rat hippocampal progenitor (AHP) cells. Both hexarelin and ghrelin stimulated increased incorporation of (3)H-thymidine, indicating an increased cell proliferation. Furthermore, hexarelin, but not ghrelin, showed protection against growth factor deprivation-induced apoptosis, as measured by annexin V binding and caspase-3 activity and also against necrosis, as measured by lactate dehydrogenase release. Hexarelin activated the MAPK and the phosphatidylinositol 3-kinase/Akt pathways, whereas ghrelin activated only the MAPK pathway. AHP cells did not express the GHS receptor 1a, but binding studies could show specific binding of both hexarelin and ghrelin, suggesting effects to be mediated by an alternative GHS receptor subtype. In conclusion, our results suggest a differential effect of hexarelin and ghrelin in AHP cells. We have demonstrated stimulation of (3)H-thymidine incorporation with both hexarelin and ghrelin. Hexarelin, but not ghrelin, also showed a significant inhibition of apoptosis and necrosis. These results suggest a novel cell protective and proliferative role for GHS in the central nervous system.
|
|
| 41. |
- Kairisalo, Minna, et al.
(författare)
-
NF-kappaB-dependent regulation of brain-derived neurotrophic factor in hippocampal neurons by X-linked inhibitor of apoptosis protein.
- 2009
-
Ingår i: The European journal of neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 30:6, s. 958-66
-
Tidskriftsartikel (refereegranskat)abstract
- X chromosome-linked inhibitor of apoptosis protein (XIAP) is an anti-apoptotic protein enhancing cell survival. Brain-derived neurotrophic factor (BDNF) also promotes neuronal viability but the links between XIAP and BDNF have remained unclear. We show here that the overexpression of XIAP increases BDNF in transgenic mice and cultured rat hippocampal neurons, whereas downregulation of XIAP by silencing RNA decreased BDNF. XIAP also stimulated BDNF signaling, as shown by increased phosphorylation of the TrkB receptor and the downstream molecule, cAMP response element-binding protein. The mechanism involved nuclear factor-kappaB (NF-kappaB) activation and blocking of NF-kappaB signaling inhibited the increased activities of BDNF promoters I and IV by XIAP. In neuronal cultures XIAP also upregulated interleukin (IL)-6, which is an NF-kappaB-responsive gene. The addition of IL-6 elevated whereas incubation with IL-6-blocking antibodies reduced BDNF in the neurons. BDNF itself activated NF-kappaB in the neurons at higher concentrations. The data show that XIAP has trophic effects on hippocampal neurons by increasing BDNF and TrkB activity. The results reveal a cytokine network in the brain involving BDNF, IL-6 and XIAP interconnected via the NF-kappaB system.
|
|
| 42. |
- Kairisalo, M., et al.
(författare)
-
X-linked inhibitor of apoptosis protein increases mitochondrial antioxidants through NF-kappaB activation
- 2007
-
Ingår i: Biochem Biophys Res Commun. - 1090-2104. ; 364:1, s. 138-44
-
Tidskriftsartikel (refereegranskat)abstract
- X chromosome-linked inhibitor of apoptosis protein is an endogenous inhibitor of caspases and is an important regulator of cell death. XIAP can also influence cell signaling, but downstream proteins affected are largely unknown. We show here using neuronal PC6.3 cells that XIAP increases the levels of antioxidants, particularly superoxide dismutase-2 that is localized to mitochondria. Studies using reporter constructs and NF-kappaB Rel-A deficient mouse embryonic fibroblasts showed that NF-kappaB signaling is required for the induction of Sod2 by XIAP. XIAP also reduced oxidative stress in the PC6.3 cells as shown by decreased production of reactive oxygen species. These findings disclose a novel role for XIAP in control of oxidative stress and mitochondrial antioxidants that may contribute to cell protection after various injuries.
|
|
| 43. |
- Kalm, Marie, 1981, et al.
(författare)
-
C3 deficiency ameliorates the negative effects of irradiation of the young brain on hippocampal development and learning.
- 2016
-
Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:15, s. 19382-94
-
Tidskriftsartikel (refereegranskat)abstract
- Radiotherapy in the treatment of pediatric brain tumors is often associated with debilitating late-appearing adverse effects, such as intellectual impairment. Areas in the brain harboring stem cells are particularly sensitive to irradiation (IR) and loss of these cells may contribute to cognitive deficits. It has been demonstrated that IR-induced inflammation negatively affects neural progenitor differentiation. In this study, we used mice lacking the third complement component (C3-/-) to investigate the role of complement in a mouse model of IR-induced injury to the granule cell layer (GCL) of the hippocampus. C3-/- and wild type (WT) mice received a single, moderate dose of 8 Gy to the brain on postnatal day 10. The C3-/- mice displayed 55 % more microglia (Iba-1+) and a trend towards increase in proliferating cells in the GCL compared to WT mice 7 days after IR. Importantly, months after IR C3-/- mice made fewer errors than WT mice in a reversal learning test indicating better learning capacity in C3-/- mice after IR. Notably, months after IR C3-/- and WT mice had similar GCL volumes, survival of newborn cells (BrdU), microglia (Iba-1) and astrocyte (S100β) numbers in the GCL. In summary, our data show that the complement system contributes to IR-induced loss of proliferating cells and maladaptive inflammatory responses in the acute phase after IR, leading to impaired learning capacity in adulthood. Targeting the complement system is hence promising for future strategies to reduce the long-term adverse consequences of IR in the young brain.
|
|
| 44. |
- Kalm, Marie, 1981, et al.
(författare)
-
Irradiation-induced loss of microglia in the young brain.
- 2009
-
Ingår i: Journal of neuroimmunology. - : Elsevier BV. - 0165-5728. ; 206:1-2, s. 70-5
-
Tidskriftsartikel (refereegranskat)abstract
- Irradiation-induced loss of neural stem and progenitor cells may contribute to cognitive deficits. Furthermore, subsequent inflammation inhibits neural progenitor cell differentiation. Here we have characterized the microglia response after a single dose of 8 Gy to the brains of postnatal day 9 or 21 rats. The number of Iba-1-positive microglia increased 6 h after IR but had decreased 7 days later, below control levels, and this decrease was more pronounced in P9 rats. Active caspase-3 and TUNEL staining revealed irradiation-induced microglia death. This age-dependent IR-induced loss of microglia likely affects both the response to IR and further brain development.
|
|
| 45. |
- Kalm, Marie, 1981, et al.
(författare)
-
Lipopolysaccharide sensitized male and female juvenile brains to ionizing radiation
- 2013
-
Ingår i: Cell Death & Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 4:e962
-
Tidskriftsartikel (refereegranskat)abstract
- Radiotherapy is an effective tool in the treatment of pediatric malignancies but it is associated with adverse side effects, both short- and long-term. One common long-term side effect after cranial radiotherapy is cognitive impairment and this is, at least partly, thought to be caused by reduced hippocampal neurogenesis. Neuroinflammation and a perturbed microenvironment are thought to be important in the dysregulation of neurogenesis seen after irradiation (IR). We investigated the effects of a preexisting, lipopolysaccharide (LPS)-induced systemic inflammation at the time of IR in both males and females. A single dose of 8 Gy to the brain of postnatal day 14 mice caused an upregulation of cytokinesichemokines (IL-1/1, MIP-1 IL-12, GM-CSF, MIP1 z, IL-17, CCL2 and KC) 6 h after IR, more so in females. Caspase-3 activity, reflecting apoptosis and possibly microglia activation, was elevated 6 h after IR. Females treated with LPS before IR showed a higher caspase-3 activity compared with males. During the chronic phase (3 months post IR), we found that LPS-induced inflammation at the time of IR aggravated the IR-induced injury in both male and female mice, as judged by reduced bromodeoxyuridine incorporation and neurogenesis (doublecortin-positive cells) in the hippocampus. At this late time point, the microglia density was increased by IR, more so in females, indicating long-term effects on the microenvironment. IR increased anxiety-related behavior in vehicle-, but not LPS-, treated animals. However, exploratory behavior was affected by IR in both vehicle- and LPS-treated mice. In conclusion, we found that LPS administration before IR of the young mouse brain aggravated the injury, as judged by reduced hippocampal neurogenesis. This supports the clinical practice to postpone radiotherapy if the patient shows signs of infection. Systemic inflammation is not always obvious, though, for example because of concurrent corticosteroid treatment, so careful monitoring of inflammation is warranted.
|
|
| 46. |
- Kalm, Marie, 1981, et al.
(författare)
-
Loss of hippocampal neurogenesis, increased novelty-induced activity, decreased home cage activity, and impaired reversal learning one year after irradiation of the young mouse brain
- 2013
-
Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886 .- 1090-2430. ; 247, s. 402-409
-
Tidskriftsartikel (refereegranskat)abstract
- Radiotherapy is a major cause of long-term complications in survivors of pediatric brain tumors. These complications include intellectual and memory impairments as well as perturbed growth and puberty. We investigated the long-term effects of a single 8Gy irradiation dose to the brains of 14-day-old mice. Behavior was assessed one year after irradiation using IntelliCage and open field, followed by immunohistochemical investigation of proliferation and neurogenesis in the dentate gyrus of the hippocampus. We found a 61% reduction in proliferation and survival (BrdU incorporation 4weeks prior to sacrifice), 99% decrease in neurogenesis (number of doublecortin-positive cells) and gliosis (12% higher astrocyte density) one year following irradiation. Irradiated animals displayed increased activity in a novel environment but decreased activity in their home cage. Place learning in the IntelliCage was unaffected by irradiation but reversal learning was impaired. Irradiated animals persevered in visiting previously correct corners to a higher extent compared to control animals. Hence, despite the virtual absence of neurogenesis in these old mice, spatial learning could take place. Reversal learning however, where a previous memory was replaced with a new one, was partly impaired. This model is useful to study the so called late effects of radiotherapy to the young brain and to evaluate possible interventions.
|
|
| 47. |
- Kalm, Marie, 1981, et al.
(författare)
-
Transient inflammation in neurogenic regions after irradiation of the developing brain.
- 2009
-
Ingår i: Radiation research. - 0033-7587. ; 171:1, s. 66-76
-
Tidskriftsartikel (refereegranskat)abstract
- Kalm, M., Fukuda, A., Fukuda, H., Ohrfelt, A., Lannering, B., Björk-Eriksson, T., Blennow, K., Márky, I. and Blomgren, K. Transient Inflammation in Neurogenic Regions after Irradiation of the Developing Brain. Radiat. Res. 171, 66-76 (2009).We characterized the inflammatory response after a single dose of 8 Gy to the brains of postnatal day 9 rats. Affymetrix gene chips revealed activation of multiple inflammatory mechanisms in the acute phase, 6 h after irradiation. In the subacute phase, 7 days after irradiation, genes related to neurogenesis and cell cycle were down-regulated, but glial fibrillary acidic protein (GFAP) was up-regulated. The concentrations of 14 different cytokines and chemokines were measured using a microsphere-based xMAPtrade mark technology. CCL2, Gro/KC and IL-1alpha were the most strongly up-regulated 6 h after irradiation. CCL2 was expressed in astrocytes and microglia in the dentate gyrus and the subventricular zone (SVZ). Hypertrophy, but not hyperplasia, of astrocytes was demonstrated 7 days after irradiation. In summary, we found transient activation of multiple inflammatory mechanisms in the acute phase (6 h) after irradiation and activation of astrocytes in the subacute phase (7 days) after irradiation. It remains to be elucidated whether these transient changes are involved in the persistent effects of radiation observed on neurogenesis and cognition in rodents.
|
|
| 48. |
|
|
| 49. |
- Kuhn, Hans-Georg, 1961, et al.
(författare)
-
Developmental dysregulation of adult neurogenesis.
- 2011
-
Ingår i: The European journal of neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 33:6, s. 1115-22
-
Forskningsöversikt (refereegranskat)abstract
- Rather than a singular event that suddenly appears during adulthood, adult neurogenesis has long been recognized as the continuation of postnatal neurogenic activity. During the first postnatal weeks, significant cellular changes occur within and adjacent to germinal matrices of the subventricular zone and dentate gyrus. The majority of granule cells are generated during this period. In addition, radial glia are transformed into astrocyte-like stem cells, the ependymal layer is formed, and the highest rates of angiogenesis, gliogenesis and myelination are observed. The first postnatal weeks are critical as the brain growth rate is maximal, and changes during this period can have a great impact on neurogenesis levels and overall brain function later in life. This review chronicles cellular changes and some of the clinically relevant dysregulations that can occur during the postnatal period, and discusses the possible impact of these changes on neurogenesis and cognitive function later in life.
|
|
| 50. |
- Li, Hongfu, et al.
(författare)
-
Lithium-mediated long-term neuroprotection in neonatal rat hypoxia-ischemia is associated with antiinflammatory effects and enhanced proliferation and survival of neural stem/progenitor cells.
- 2011
-
Ingår i: Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016. ; 31:10, s. 2106-2115
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the long-term effects of lithium treatment on neonatal hypoxic-ischemic brain injury, inflammation, and neural stem/progenitor cell (NSPC) proliferation and survival. Nine-day-old male rats were subjected to unilateral hypoxia-ischemia (HI) and 2mmol/kg lithium chloride was injected intraperitoneally immediately after the insult. Additional lithium injections, 1mmol/kg, were administered at 24-hour intervals for 7 days. Animals were killed 6, 24, 72hours, or 7 weeks after HI. Lithium reduced total tissue loss by 69%, from 89.4±14.6mm(3) in controls (n=15) to 27.6±6.2mm(3) in lithium-treated animals (n=14) 7 weeks after HI (P<0.001). Microglia activation was inhibited by lithium treatment, as judged by Iba-1 and galectin-3 immunostaining, and reduced interleukin-1β and CCL2 levels. Lithium increased progenitor, rather than stem cell, proliferation in both nonischemic and ischemic brains, as judged by 5-bromo-2-deoxyuridine labeling 24 and 72hours as well as by phospho-histone H3 and brain lipid-binding protein labeling 7 weeks after HI. Lithium treatment also promoted survival of newborn NSPCs, without altering the relative levels of neuronal and astroglial differentiation. In summary, lithium conferred impressive, morphological long-term protection against neonatal HI, at least partly by inhibiting inflammation and promoting NSPC proliferation and survival.Journal of Cerebral Blood Flow & Metabolism advance online publication, 18 May 2011; doi:10.1038/jcbfm.2011.75.
|
|
