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Experimental bridging of spinal cord injury with hydrogels
Hejčl, Aleš ; Syková, Eva (advisor) ; Rokyta, Richard (referee) ; Filip, Stanislav (referee)
Hydrogels are biomaterials used in the treatment of experimental spinal cord injury (SCI). In a model of acute SCI, we implanted hydrogels based on 2-hydroxyethylmethacrylate (HEMA) and hydroxypropylmethacryla-mide (HPMA). One month after implantation the hydrogels bridged the cavity, adhered well to the spinal cord and created permissive environment, infiltrated with blood vessels, axons and Schwann cells. Physical modifications (e.g. surface charge) of hydrogels may improve bridging of acute SCI. We implanted hydrogels based on HEMA with a surface charge in spinal cord hemisection and compared with a hydrogel without charge. Hydrogels with surface charge improved connective tissue adhesion and growth of axons compared to a hydrogel without charge. Biodegradable hydrogels may bridge a lesion followed by complete re-sorption. In a model of acute SCI we implanted hydrogels based on the copolymer of HPMA and etoxyethylmethacrylate (EOMA) degraded from the periphery, which was substituted with new tissue after 1 month, to the center, comprising amorphous residuals of the hydrogel. Delayed hydrogel implantation may improve bridging of spinal cord le-sion. We implanted hydrogels based on HEMA acutely or in a delayed fashion (after 7 days) in spinal cord transection. Delayed implantation re-duced the volume of...
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Astrocytic changes in a mouse model of Alzheimer's disease
Kulijewicz-Nawrot, Magdalena ; Syková, Eva (advisor) ; Rokyta, Richard (referee) ; Zach, Petr (referee)
1. SUMMARY: In this thesis we reported astrocytic atrophy characterized by a reduction in the surface area and volume of GFAP-positive glial cells in the prefrontal cortex of 3xTg-AD mice - an important morphological alteration starting far before any well known histopathological hallmark of AD. This change is present in parallel with homeostatic failure suggested by the decreased expression of GS. Those alterations can have drastic effects on brain connectivity and the biochemistry of the main neurotransmitters within the brain, such as glutamate and GABA. GFAP is implicated in a variety of processes, such as cell migration and proliferation, neurite outgrowth, astrocytic glutamate transporter expression (GLAST and GLT-1) and synaptic plasticity, so that every change can shift the astrocytes' role from physiology to pathology. In the case of affected GFAP-IR astrocytes, the withdrawal of processes from neurons and synapses can lead to a severe transmission crush, due to the uncontrolled spillover of the neurotransmitter from the synaptic cleft, inadequate metabolic support and the lack of a physiological barrier between the affected synapse and other synapses in its close vicinity. This will directly disturb the reciprocal connections between the affected brain regions, inluding the important structures...
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Neurogenic pulmonary edema in rats with spinal cord injury
Šedý, Jiří ; Syková, Eva (advisor) ; Herget, Jan (referee) ; Rokyta, Richard (referee)
N urogenic puhnonary edema (NPE) is an acu te life-threatening complication of the c ntral nervous system (CNS) injury. Anesthetics can either promote or inhibit the NPE development. We examined the role of different concentrations of isoflurane anesthesia (1.5 - 3%) on the developmen t of NPE in rats with balloon compressed spinal cord. The development of NPE was examined in vivo and on histological sections of lung tissue. Neurological recovery in animals anesthetized with 1.5% or 3% isoflurane was monitored using BBB and pian tar tests for 7 weeks post-injury. The grade of the spinal gray and white matter sparing was evaluated using morphornetry. The r le of gradually developed spinal cord lesíon and spínal cord transection in the developmen t of NPE were evaluated also. NPE developed in all animals anesthetized with 1.5-2% isofluran . Almost 42% of animals died due to massive pulmonary bleeding and suffocation; X-ray imaging, pulmonary index and histological sections showed massive NPE. More than 71 % of animals anesthetized with 2.5-3% i oflu rane had no signs of NPE. Blood pressure rose more rapidly in animals from 1.5% group than in 3% group; this hypertensive reaction was caused by the sympathetic hyperactivi ty. Animals from 3% group recovered their motor and sensory func tions more rapidly than...
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Neuroregeneration after spinal cord injury and in amyotrophic lateral sclerosis -possibilities for stem cell therapy
Forostyak, Serhiy ; Syková, Eva (advisor) ; Rokyta, Richard (referee) ; Mazanec, Radim (referee)
Adipose-derived MSC could be used as an alternative for bone marrow MSC in the treatment of acute SCI. We used the intraspinal grafting of rat adipose-derived naïve and predifferentiated MSC to improve motor function after a balloon-induced compression lesion of the rat spinal cord. Grafted cells survived for seven weeks after transplantation, improved motor activity and integrated into the host tissue. They expressed the oligodenrocyte precursor marker NG2 and, occasionally, the astrocytic marker GFAP, but did not transdifferentiate into a neuronal phenotype. Bone marrow MSC may change the disease course and extend lifespan in a rat model of ALS. Combined intraspinal and intravenous transplantation of rat BMSC was performed in symptomatic rats overexpressing the SOD1 G93A gene. Cell-treated animals lived longer compared with sham-treated rats and displayed significantly improved motor activity and grip strength. Rat BMSC survived until the end stage of the disease and were migrating along the white matter of the spinal cord. Grafted cells increased the number of host cells displaying positive staining for neurofilaments and significantly increased the number and also the size of the remaining spinal motoneurons 10-11 weeks after delivery, compared with vehicle-injection. The defragmentation of DNA, a sign...
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Extracellular space diffusion parameters and metabolism in the rat somatosrensory cortex during recovery from trabsient global ischemia and hypoxia
Zoremba, Norbert ; Syková, Eva (advisor) ; Mareš, Pavel (referee) ; Rokyta, Richard (referee)
Content Abstract .................................................................. ..... ...... ............................ .... 2 Introduction ............................................ ........................................ .................. 4 Aims .................. ................. ................................ ....... ..... . ............ .......... 6 Methods ............................................... ......................................................... ... 7 Results ................ ............................................................................ .................. 9 Discussion .. ... ............... .. ......... .. .......................... ............................. ... ............. 13 References ....... ................................................................ ....................... ........ 20 List of Publications ............. .... .. ............... .. ... .. .......... .. ... ............................... .... 22 Abstract The extracellular space (ECS) of the brain represents the microenvironment of nerve cells and enables the diffusion of neuroactive substances among neurons, axons and glia. Changes in the ECS diffusion parameters during ischemia are well known, but information about changes in ECS diffusion and energy-related metabolite...
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Diffusion parameters of brain tissue during ischemia and during status epilepticus
Šlais, Karel ; Syková, Eva (advisor) ; Otáhal, Jakub (referee) ; Rokyta, Richard (referee) ; Dezortová, Monika (referee)
Difusion of neuroactive substances in the extracellular space (ECS) is constrained by two factors: extracellular space volume and geometry. We have shown changes of diffusion parameters and extracellular concentrations of energetic metabolites and glutamate in two pathological states accompanied by significant ECS volume changes - in combined hypoxia/ischemia and in status epilepticus. In the model of hypoxia/ischemia, we have shown time courses of diffusion parameters, concentrations of glucose, lactate, lactate/pyruvate ratio and glutamate during hypoxic/ischemic insult and after reperfusion. The time course of glutamate extracellular concencetration in transient hypoxia/ischemia correlated well with time course of changes in diffusion parameters. The decrease in the ECS volume fraction can therefore contribute to an increased accumulation of toxic metabolites, which may aggravate functional deficits and lead to damage of the central nervous system. In the model of pilocarpine-induced status epilepticus our results show changes in the extracellular space diffusion parameters, K+, energy-related metabolites and glutamate during the initiation and first hours of the propagation. Our results also show that the first minutes after a pilocarpine injection are followed by an increase in extracellular K+ and a...
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název v anglickém jazyce není uveden
Glogarová, Kateřina ; Syková, Eva (advisor) ; Langmeier, Miloš (referee) ; Rokyta, Richard (referee)
Magnetic resonance imaging (MRI) provides a useful noninvasive method to study the long-term migration and fate of transplanted stem cells in the central nervous system in vivo. Grafted adult as well as embryonic stem cells (ESCs) labeled with superparamagnetic nanoparticles survive in the host organism and migrate preferentially into a lesion site, where they populate the damaged nervous tissue. The migration is not affected by the route of administration; the lesion is populated with the same number of cells after intracerebral grafting as after intravenous injection. Less than 3 % of transplanted mesenchymal stem cells (MSCs) in a cortical photochemical lesion differentiated into neurons and none into astrocytes, while most ESCs (70 %) differentiated into astrocytes and only 5 % into neurons. The intravenous injection of MSCs or of the mononuclear fraction of the bone marrow, which includes hematopoietic and nonhematopoietic stem cells, progenitors and lymphocytes (BMCs), as well as the mobilization of endogenous BMCs with G-CSF (granulocyte colony stimulating factor) significantly improved the recovery of hind limb motor function and sensitivity in rats with a spinal cord compression lesion and significantly increased the spared white matter volume in the center of the lesion. The recovery was most...
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Biomaterials and stem cells in spinal cord injury
Tukmachev, Dmitry ; Syková, Eva (advisor) ; Dubový, Petr (referee) ; Sameš, Martin (referee)
Spinal Cord Injury is a very serious trauma which can't be effectively cured at present time. The use of ECM hydrogels as supportive and stimulatory milieu and transplantation of stem cells represent promising approaches for SCI therapy. However, current treatments are limited by inefficient delivery of stem cells into the lesion site. Therefore, the aim of this study was the development of SCI treatment using ECM hydrogels and effective stem cell delivery system. The non-invasive magnetic system was designed and used to accumulate SPION-labelled stem cells at a specific site of a SCI lesion. Decellularized porcine SC and UB tissues, synthetic P(HEMA-AEMA) hydrogel with oriented porosity and modified hyaluronic acid HA-PH-RGD were transplanted into a spinal cord lesion of rats with or without stem cells, followed by histological analysis and gene expression analysis. All types of hydrogels integrated into the lesion and stimulated neovascularization and axonal ingrowth into the lesion. There was no significant difference in the tissue infiltration between the plain hydrogels and those seeded with stem cells. However, a subacute injection HA-PH- RGD/Fibrinogen combined with Wharton's jelly-derived human mesenchymal stem cells enhanced axonal ingrowth into the lesion. Significant down-regulation of...
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Impairment of rat hippocampus after irradiation with leksell gamma knife and evoked proliferation in gyrus dentatus of the adult rat
Náměstková, Kateřina ; Syková, Eva (advisor) ; Druga, Rastislav (referee) ; Rokyta, Richard (referee)
The hippocampus is a brain structure that has been extensively studied in the context of learning and memory has been considered to be involved in processing of emotion as part of the limbic system. This organ was initially connected with the sense of smell and around 1900 the role of the hippocampus in memory was noted by Vladimir Bechterev. The significance of this structure for processing of memory was revealed after William Scoville and Brenda Millner released a report in 1957 about their 10 patients who showed impaired short-term memory after bilateral lesions to the medial temporal lobe, including the hippocampus. This form of surgery was introduced in 1954 to treat pharmacoresistant epilepsy, psychosis, and depression with therapeutic success. The severity of the mainly anterograde amnesia was related to the size of the removed medial temporal lobe portion (Scoville and Millner 1957). The most radical surgery was performed on the patient H.M., who has been seen by more than hundred investigators until today (Corkin 2002). Fig. Powered by TCPDF (www.tcpdf.org)
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