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Ovarian stimulation and related hyperstimulation syndrome
Pohlová, Nikola ; Komrsková, Kateřina (advisor) ; Ješeta, Michal (referee)
Ovarian stimulation is a key process of assisted reproduction and it helps women in the treatment of infertility. Hormonal ovarian stimulation ensures the growth and development of ovarian follicles. The selected dominant follicle releases an oocyte during ovulation, which is destined for fertilization. In methods of artificial fertilization, multiple follicles are stimulated, and more oocytes are retrieved. The retrieved oocytes are then fertilised in vitro. In this thesis, the benefits and risks of the commonly used stimulation protocols are discussed. The focus is on optimizing stimulation for individual patients, considering their health status, functional ovarian reserve, and individual needs. Special stimulation protocols for patients with polycystic ovary syndrome and for patients with cancer are presented. Ovarian stimulation is also applied to oocyte donors. The most serious risk of ovarian stimulation is ovarian hyperstimulation syndrome. Ovarian stimulation is also used in the rescue of endangered mammalian species or in the breeding of domesticated animals. The study of ovarian stimulation is important for the improvement of reproductive methods in human and veterinary medicine. Key words: follicles, ovarian stimulation, assisted reproduction, ovulation, risks
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Current knowledge and challenges associated with embryo transfer in assisted reproduction in humans and selected mammals.
Hrdová, Lucie ; Komrsková, Kateřina (advisor) ; Cozlová, Nina (referee)
The embryo transfer represents the final and pivotal step of in vitro fertilization, which leads to a successful implantation of the embryo into the uterus and subsequent birth of a healthy offspring if executed correctly. This bachelor thesis focuses on the technique of transfer using a catheter and the potential complications associated with it, including the optimal timing for the procedure. Furthermore, differences in forms of embryo transfer are discussed, assessing advantages and risks, comparing single and multiple, as well as fresh and frozen embryo transfer. The thesis introduces the related topic of cryopreservation and the possibilities in terms of preserving embryos for future use. This thesis also covers hormonal stimulation and uterine response, addressing specifically the role of gonadotropins, steroid hormones, prostaglandins, and the potential positive influence of human growth hormone on optimizing successful outcomes in assisted reproduction. Additionally, possible complications associated with embryo transfer in the early stages of pregnancy, as well as complications that may arise before the actual embryo implantation occurs are covered. Lastly, the issues related to embryo transfer in the context of controlled breeding of selected domesticated animals and endangered mammalian...
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Comparison of immunomodulatory properties of mesenchymal stem cells and Sertoli cells
Porubská, Bianka ; Krulová, Magdaléna (advisor) ; Komrsková, Kateřina (referee) ; Filipp, Dominik (referee)
Cell therapies are increasingly considered in preclinical studies and in the future of medicine. The main cell type investigated in this manner is mesenchymal stem cells (MSCs), because of their strong immunomodulatory properties. The efficacy of the therapy depends on various aspects, such as the viability and source of MSCs, the purity of the cell suspension and many more. There is a need for more tailored therapy and the use of cell type better fitting for the specific pathology. Sertoli cells (SCs) are deemed by some authors to be a kind of MSCs, namely because of their similar immunomodulatory properties. Because they reside in the seminiferous tubules in the testes, they are a promising candidate for the treatment of inflammatory pathologies of testicular tissue, such as bacterial infection-induced infertility. In vitro comparison of the ability of MSCs and SCs to differentiate into mesenchymal cell lineages such as osteocyte, chondrocyte, and adipocyte showed success in the case of SCs, providing evidence for their mesenchymal origin. The effect of MSCs or SCs on activated immune cells in vitro showed immunosuppression in both cases with distinct features. MSCs suppressed Th17 cell activation and IL-17 production by CD4+ T cells and SCs down-regulated TNFα and IL-2 production by these cells,...
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The role of centrobin in spermatogenesis
Flintová, Jennifer ; Komrsková, Kateřina (advisor) ; Šebková, Nataša (referee)
Spermatogenesis is a highly orchestrated, strictly regulated cascade of events that could be divided into three major processes: mitotic expansion of diploid germ cells (spermatocytogenesis), meiotic division creating haploid cells, and spermiogenesis. Spermiogenesis, the final stage of spermatogenesis comprises a striking metamorphosis of round haploid spermatids into morphologically and functionally specialized spermatozoa designed for the fertilization. One of the proteins indispensable for proper sperm morphogenesis is centrobin, a structural component of the specialized cytoskeletal structures of the elongating spermatids (acroplaxome and manchette), executing essential role in sperm head shaping and assembly of the head-tail coupling apparatus. Disruption in Cntrob gene (coding for centrobin) in rats homozygous at the hd (hypodactyly) locus results in male infertility, with a striking morphological signature called "decapitated sperm syndrome" with detachment of sperm head from the flagellum due to impaired head-tail coupling. However, molecular function of centrobin in spermiogenesis is still unknown. Sperm decapitation is a distinct phenotype described in several mouse mutants and importantly from infertile human males. Strikingly, in addition to proteins functioning in cytoskeletal...
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Fc receptor-like molecules: biological role and phylogenetic conservation of FcRL multigene family
Böhmová, Helena ; Komrsková, Kateřina (advisor) ; Vinkler, Michal (referee)
Fc receptor-like (FcRL) molecules are novel immunological receptors with intriguing proposed roles in the immune system. Phylogenetic studies revealed that FcRL genes are conserved in jawed vertebrates (Gnathostomata), and likely formed during adaptive system genesis. FcRLs have multiple extracellular immunoglobulin domains, and some representatives have newly documented specific ligands. Several FcRLs contain both ITIM and ITAM cytoplasmatic sequences, which provide them with dual signalling properties. These allow them to regulate intracellular signalling pathways. FcRLs are known to engage in B cell regulation. They are largely expressed on B cells, with some representatives preferentially expressed on cytotoxic T cells and NK cells. Their expression patterns are specific to distinct B cell subpopulations and also show different levels of expression during B cell differentiation, pointing to their possible involvement in this process. FcRL molecules have also been detected on the mammalian eggs, and they may potentially play role in gamete fusion. This thesis aims to introduce FcRL molecules in various aspects, including their relation to classical Fc receptors, their structural properties, genomic organisation, phylogenetic conservation and their roles in organism. Thesis also focuses on...
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The role of LINC complex in male germinal cells
Kmoníčková, Věra ; Komrsková, Kateřina (advisor) ; Knop, Filip (referee)
LINC (linker of the nucleoskeleton and cytoskeleton) complex is substantial for the overall function of any nuclear cell. It is a bridge between the cytoplasmic and nuclear structures which mediates transmission of mechanical forces generated on the cytoplasmic side. The main objective of this thesis is the function of distinct variants of the LINC complexes in mammalian male germinal cells throughout their development. The nuclear facing side of the LINC complex is a key player in homolog pairing and rapid chromosome movements during meiosis. The cytoplasmic facing side is necessary for the sperm head formation, proper acrosome and nucleus attachment. Evenly, another complex is essential for the head-to-tail coupling as without this one the sperm cells are found decapitated. If the subunits of the LINC complex are defective, males are afflicted with different kinds of infertilities, which nowadays is one of the important issues of our society. Many things about the role and structure of the LINC complex has been discovered due to modern technologies. These up to date findings are summarized and discussed on the following pages.
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LINC complex: The link between chromatin integrity and sperm motility
Šanovec, Ondřej ; Komrsková, Kateřina (advisor) ; Lánská, Eva (referee)
The LINC complex (Linker of the Nucleoskeleton and Cytoskeleton) is a protein structure located in the nuclear membrane that connects the cytoskeleton with the nucleoskeleton. This complex can be found in every mammalian cell including the gametes. However, here the LINC complex is more diverse and less studied than in the somatic cells. In this thesis, the LINC complex and its role in spermiogenesis have been studied in wild-type and Protamine 2 knockout (Prm2-/- ) mice. Protamines are small proteins that replace histones during spermiogenesis. The mouse model generated by the group of prof. Hubert Schorle has a deletion in Prm2 in exon 1 and its sperm possess a surprising phenotype including complete loss of motility. Therefore, it was hypothesized that the LINC complex might be responsible for miscommunication between the sperm head and tail which leads to the loss of sperm motility. Results from this study suggest that the LINC complex is not influenced by Prm2 deletion, however, actin dynamics, cytoskeletal motor proteins and tubulin acetylase/ histone deacetylase activity might be impaired. Prm2-/- sperm have a significantly higher abundance of β-actin compared to the wild type. Next, Prm2-/- sperm also show a different pattern of acetylation of α-tubulin but no change in the abundance of...
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Chemical communication of gametes
Otčenášková, Tereza ; Komrsková, Kateřina (advisor) ; Petr, Jaroslav (referee)
Fertilization is a multiple step process leading to fusion of female and male gametes resulting in a formation of a zygote. Besides direct gamete interaction via binding receptors localized on both oocyte and sperm surface, fertilization also involves communication based on chemical molecules triggering various signalling pathways. This work is aimed to characterize chemical communication of gametes of a model organism Mus musculus. For this purpose, modern proteomic and visualisation methods like nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS), selected reaction monitoring (SRM) and immunofluorescent microscopy were used. Lipocalins were identified as candidate proteins involved in communication including those from major urinary proteins (MUPs), LCN lipocalins and fatty acid binding proteins (FABPs). For the first time, we report their presence in the sperm acrosome. Based on lipocalins capacity to bind and transport other molecules, we propose that these proteins have a protective and/or signalling role for gametes. Furthermore, chemical communication between sperm and oocyte is based on chemotaxis which enables their interaction before their fusion. In this work, we detected that spermatozoa show chemotactic responses in the presence of L-glutamate. This amino acid naturally...
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Male fertility disorders and sperm damage related to COVID-19 disease.
Pikulová, Simona ; Komrsková, Kateřina (advisor) ; Ješeta, Michal (referee)
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the coronavirus disease 2019 (COVID-19), which has spread rapidly worldwide since the end of 2019. The virus causes serious health problems and damage to human organs, especially the lungs, kidneys, brain, heart and testicles, which can be fatal. This work deals with the entry of SARS- CoV-2 virus into the testicles and sperm damage due to infection. Receptors are described in more detail, specifically the membrane receptor ACE2, which mediates the entry of the virus into germ cells (spermatogonia) and somatic testicular cells (Sertoli and Leydig), which express this receptor. In this work, the mechanisms causing infection are described and attention is focused to changes in the signaling pathways due to SARS-CoV-2 and ACE2 binding. Consequently, the presence of the virus leads to hormonal imbalances, local oxidative stress and inflammation, which affect the course of spermatogenesis and can cause pathological conditions of spermatozoa such as motility disorders or DNA fragmentation and thus adversely affect male fertility. Key words: COVID-19, SARS-CoV-2, male infertility, sperm, ACE2
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