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Use of biological materials for tissue substitution in plastic surgery
Měšťák, Ondřej ; Sukop, Andrej (advisor) ; Brychta, Pavel (referee) ; Dražan, Luboš (referee)
Užití biologických materiálů k náhradě tkání v plastické chirurgii ! Abstrakt v angličtině Background: Biological meshes are biomaterials consisted of extracellular matrix and used in surgery particularly for hernia treatment or thoracic wall reconstruction. They are capable of vascularization, that decreases risk of infection, expecially when used in contaminated fields. This study compared the strength of incorporation and biocompatibility of two porcine-derived grafts (cross-linked and non-cross-linked) in a rat hernia model. In addition, we hypothesized that combination of extracellular matrices with autologous mesenchymal stem cells used for hernia repair would result in increased vascularization and increased strength of incorporation. Methods: Standardized 2 x 4 cm fascial defect was created in 42 Wistar rats and repaired with a cross-linked or a non-cross-linked graft either enriched or non-enriched with stem cells. The rats were sacrificed 3, 6 and 12 months later. The strength of incorporation, vascularization, cellular invasion, foreign body reaction and capsule formation were evaluated. Results: Comparison of stem cell enriched and non-enriched groups showed no significant differences in the capsule thickness, foreign body reaction, cellularization or vascularization. In the non-cross-linked...
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Possibilities of using stem cells for treatment of ocular surface injuries
Kössl, Jan ; Holáň, Vladimír (advisor) ; Drbal, Karel (referee)
Ocular surface defects are one of the most common causes of impaired vision or even blindness. Corneal transplantation is the first choice of the treatment of these defects. If the damage is extensive and includes the limbus, niche of limbal stem cells (LSCs), LSC deficiency (LSCD) occurs and reparation with regeneration of cornea is impaired. The only way to treat LSCD is limbal transplantation or transplantation of autologous LSCs from the healthy eye. In cases of bilateral LSCD there are no autologous LSCs available. The use of allogeneic LSCs is associated with the requirement of systemic or local administration of immunosuppressive drugs which have often negative side-effects and outcomes remain uncertain. The alternative for treatment of ocular surface defects and LSCD is finding a new source of an appropriate autologous stem cell substitute which are e.g. mesenchymal stem cells (MSCs). These cells can be obtained from bone marrow or adipose tissue of the particular patient. MSCs can be easily cultivated ex vivo and can be transferred onto the damaged ocular surface using appropriate scaffold. Here they can differentiate to corneal epithelial cells, have immunomodulatory properties and produce numerous trophic and growth factors. The experiments with MSCs on animal models of mechanically or...
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Targeted differentiation of mesenchymal stem cells and their clinical application
Hámor, Peter ; Kubinová, Šárka (advisor) ; Trošan, Peter (referee)
The goal of this work is to point out possibilities of neuronal differentiation of mesenchymal stem cells and their application for clinical purposes, primary for repairing and regeneration of central nervous system tissues. Because this system works as a control center for functional features of the whole body, and treating this injuries and degenerations often bring many problems and obstacles, the possibility of using autologous cells for a transplantation or inducer of the natural regenerative properties of tissues is worth deeper research. This work progressively focuses on basic characteristics of stem cells and their differentiation potential, characterizing further mesenchymal stem cells together with possibilities of their isolation and cultivation. The main part of the text is formed by studies and methods used for targeted differentiation of mesenchymal stem cells and attempts of their transdifferentiation into neural cell line, together with present and possible future application of these cells in central nervous system therapies.
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Characterization of functionalized fibres for mesenchymal stem cells cultivation and differentiation
Greplová, Jarmila ; Amler, Evžen (advisor) ; Rosina, Jozef (referee)
Modification of nanofibers is an actual trend in tissue engineering. Polyvinylacohol (PVA) is nontoxic and biodegradable polymer suitable for preparation of submicron fibers by electrospinning. Main disadvantage of PVA fibers is rapid degradation in aqueous environment. On the other hand surface of fibers contains free hydroxyl group that could be chemically modified. In recent work, chemical modification of PVA nanofibers prepared by needleless electrospinning was investigated. Polyethylenglykol (PEG) linker was introduced to the fiber surface by acylation (PVA-PEG) and further modified by biotin (PVA-PEG-b) as a function agent. Process of chemical modification does not affected fibrous morphology of samples. Interestingly, linkage of PEG-b linker promoted stability of PVA in aqueous environment. PVA-PEG-b sample was stable for 41 days. Stability of samples was strongly dependent on amount of introduced PEG-b linker, thus proposed method of modification allows to prepare nanofibers of different solubility. Additionally, biocompatibility of chemically modified nanofibers with both mesenchymal stem cells (MSC) and chondrocytes was determined. Proliferation of both cell types was not sufficient and number of cells decreased in time, probably because of high hydrophility of modified PVA scaffold. To...
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Modulation of mesenchymal stem cell properties and their use in the regulation of transplantation immunity
Peřinová, Lucie ; Krulová, Magdaléna (advisor) ; Zajícová, Alena (referee)
Mesenchymal stem cells (MSCs) represent a heterogeneous population of stromal cells with a pluripotent differentiation potential. They can be isolated from multiple tissues of mesodermal origin, such as bone marrow, adipose tissue, umbilical cord blood and peripheral blood and afterwards externally expanded according their adherence to the plastic surfaces. These cells show remarkable immunomodulatory properties, suppressing T-, B- and NK-cell functions, and also modulating dendritic cell activities and influencing immune responses during tissue repair and recovery. MSCs have been shown to possess ability to migrate to sites of inflammation and tissue injury. All these properties make MSCs a promising tool for clinical application. Our primary goal was to identify processes that may influence immunoregulatory effects of MSCs. In order to promote immunossupressive qualities of MSCs we established the scheme comprising MSCs precultivated with various cytokines and Toll-like receptors (TLR) ligands in vitro, with the final aim to improve the therapeutic effect of MSCs on wound healing in vivo. We studied modulation of MSCs properties and consequently the effect of influenced MSCs on cells of the immune system. The immunosuppression is mainly mediated through secreted factors that MSCs produced after...
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Mesenchymal stem cells and the possibility of their transdifferentiation into insulin producing cells.
Dostálová, Veronika ; Holáň, Vladimír (advisor) ; Čečrdlová, Eva (referee)
Mesenchymal stem cells (MSCs) have been demonstrated in almost all tissues of the body. Their main source is bone marrow and adipose tissue. These cells are multipotent, e.g. they are capable of differentiating into a variety of cell types. They are able to migrate into damaged tissues. Their other relevant property is a specific suppression of imunity. In the body they serve as precursors for specialized cell types and they also participate in formation of specific tissue microenvironment. Their properties represent a great potential in a wide range of clinical therapies. Besides other possible applications they could be used in the therapy of diabetes mellitus type one. During this disease insulin producing -cells are destroyed. MSCs have been used in experimental in vitro and in vivo studies to differentiate into insulin producing cells. However these cells are not able to produce sufficient amounts of insulin to exclude the supportive administration of exogenous insulin. Therefore there is a need for further research in this field of possible therapy.
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The influence of Toll-like receptors on immunomodulatory properties of mesenchymal stem cells
Heřmánková, Barbora ; Krulová, Magdaléna (advisor) ; Indrová, Marie (referee)
Immunosuppressive properties of mesenchymal stem cells (MSCs) offer potential tools for cell-based regenerative therapy and immunotherapy. MSCs express a large number of Toll like receptors (TLRs) recognizing multiple pathogen-associated molecular patterns (PAMPs), which could be found in patients microenvironment and modulate activity of MSCs. TLR ligands could lead to modulation of proliferation, differentiation, immunosuppression, migration, polarization and production of cytokine. This work discusses the effect of TLRs on immunomodulatory properties of MSCs, because there are lots of contrasts in the results about their effect.
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Targeted differenciation of limbal and mesenchymal stem cells and their therapeutic application
Kuthanová, Hana ; Holáň, Vladimír (advisor) ; Indrová, Marie (referee)
The research of stem cells slowly transfers from the experimental to the preclinical and clinical level. They are in the centre of interest thanks to their potential to treat many of severe injuries and genetically determined diseases. However, the clinical application of these cells has to be based on a basic research of their characteristics and differential potential. Adult stem cells are in organism in minor populations in unique niches. In comparison with embryonic and induced pluripotent stem cells, the adult stem cells have lower differential potential but they also tend less to making teratomas. The therapeutic use of differential and transdifferential potential of limbal and mesenchymal stem cells is described here in more detail with focus on their use in damaged ocular surface treatment. Limbal stem cells are the only source of stem cells for corneal epithelium regeneration in most organisms. Deficiency of these stem cells leads to severe eye disorders even to blindness. Nowadays, a transplantation of allogeneic limbal stem cells or allogeneic limbus is the only chance for patients with total limbal stem cell deficiency. In clinical trials with patients with particular limbal stem cell deficiency, autologous limbal stem cells were successfully transplanted. Mesenchymal stem cells derived...
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Immunomodulatory properties of mesenchymal stem cells - use in therapy
Pavlíková, Michaela ; Stříž, Ilja (referee) ; Krulová, Magdaléna (advisor)
Mesenchymal stem cells (MSC) are extensively studied mainly due to their feasible clinical application. Therapeutic potential of MSC consists not only of the ability to differentiate into mesenchymal cells, ectodermal and endodermal cell lines, but primarily in their immunomodulatory functions. Due to their effect on immune cells, MSC promote the shift of the inflammatory immune response to antiinflammatory. The ability to suppress inflammation, together with their differentiation potential and antiapoptotic potential on the surrounding cells makes MSC a promising tool for treating serious diseases. This work discusses the effect of MSC on the individual cells of the immune system. It focuses on the description of the effect of MSC in four model cases. These are an experimental autoimmune encephalomyelitis, myocardial infarction, diabetes mellitus and skin graft transplantation. The knowledge of the mechanisms of the interactions between MSC and the cells of the immune system, together with the understanding the effect of specific conditions on MSC is essential for their use in clinical therapy. Keywords: mesenchymal stem cells, immunomodulation, autoimmune diseases, transplantation
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