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Browsing by study line "Fysiologia"

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  • Äikäs, Lauri (2021)
    Abstract Introduction: Atherosclerotic cardiovascular diseases (ASCVD) cause the biggest burden on our healthcare system and cause most premature deaths. Risk for ASCVD can be lowered by lifestyle choices and medication, as well as several therapeutics such as ethyl eicosapentaenoic acid (E-EPA) supplementation. Here we aimed to investigate the effect of EEPA intervention on known ASCVD risk factors including circulating lipoprotein levels as well as low-density lipoprotein (LDL) aggregation susceptibility, a new independent risk factor for ASCVD. Study design: A study group of 39 healthy men and women participated in a 4-week long dietary supplement trial with 3.9 g/day of E-EPA. A dose of 75 µg/day of vitamin D was included in the E-EPA capsules. Blood samples were drawn before the trial, at weeks 1 and 4 of the intervention and 1 week after the intervention. The study was an open design where participants’ own baseline measurements were used to measure changes. Outcomes: The mean plasma cholesterol concentration was reduced from 3.8 mmol/l to 3.6 mmol/l (p=0.0038 one-way ANOVA) after one week of E-EPA supplementation and remained the same until the end of study period. This change was followed by a change in plasma LDL (p=0.0028 one-way ANOVA) and triglyceride (p=0.0004 one-way ANOVA) concentrations after four week and one week of E-EPA supplementation, respectively. Vitamin D levels increased on average by 18%, showcasing a lower relative response than seen in other vitamin D trials, which can be attributed to high effective baseline concentrations of vitamin D in our study group and the related negative feedback system. LDL aggregation susceptibility did not significantly change in the entire group. However, we discovered that the change in LDL aggregation susceptibility correlated negatively ( = -0.451, p = 0.0039) with the baseline LDL aggregation susceptibility. Thus, LDL aggregation decreased in participants having aggregation-prone LDL at baseline. This finding highlights a possibility that participants with higher LDL aggregation susceptibility may benefit from addition of E-EPA to their diet.
  • Uotila, Iiro (2021)
    Evolving societies force universities to transform from the producers of new information sat in their ivory towers towards the role of entrepreneurial universities. The theme of entrepreneurial universities is widely studied internationally, but studies concerning the University of Helsinki (UH) are scarce. The aim of this thesis is to map the current UH bioentrepreneurship ecosystem and the services it provides. The services were mapped and assessed based on how they match the needs of academic bioentrepreneurs. Measures are also suggested on how to develop the ecosystem. This thesis links strongly to the previous literature on entrepreneurial universities and academic entrepreneurship. Entrepreneurial university as a term encompasses an organisation, which strongly supports and encompasses entrepreneurial action in its different functions. Strong technology transfer and commercialization of research via licensing and spinout company formation, is usually linked to entrepreneurial universities. University spinouts are strongly linked to academic entrepreneurship. In spinouts research results and academic tacit knowledge are transformed into enterprises to produce value. The thesis was conducted as a qualitative case study. For the study UH affiliated entities offering entrepreneurship services and bioentrepreneurs originating from within the university were interviewed. The data was analysed with content analysis methods. The results show that UH bioentrepreneurship ecosystem is just in the beginning with multiple useful services but also with some significant flaws. The most significant obstacles preventing the growth of the ecosystem are the university’s negative culture towards entrepreneurship, non-existent communication about the subject and the absence of relevant supportive networks for academic entrepreneurs. Via changing these the critical mass to enable sustainable ecosystem can be achieved.
  • Korvenmaa, Päivi (2020)
    Female breast cancer incidence rate has been growing world-wide and it is the most common cancer in women. In the battle against the breast cancer mortality, early detection is the strongest tool. This is the reason why national mammography screening programs are widely established for selected age groups, usually for women between 50 to 70 years old. Although it is well established that these programs save lives, mammography screening is not feasible to apply to younger and/or older groups due to increasing radiation load as well as economically. There is a room for a non-invasive, easy and cost-effective breast imaging modality, which could be used for all age groups e.g. in connection with regular health checks. In this theses breast cancer as a disease and its present clinical diagnostic tools are presented. As a possible new pre-diagnostic tool, infrared imaging combined with modern analytical and machine learning tools, is introduced. Also, preliminary results of an on-going study are presented, which encourage to continue the development.
  • Ahola, Laura (2021)
    Environment is known to be a strong mediator of embryonal development and the future health of an individual. According to earlier studies, early pregnancy is especially vulnerable to environmental influence. Early embryogenesis is a critical period when epigenetic reprogramming occurs and epigenetic modifications are established. Alcohol is an environmental factor and a teratogen that affects normal epigenetic reprogramming and embryonal development. Prenatal alcohol exposure may contribute to the development of abnormal phenotype or diseases such as fetal alcohol spectrum disorders, FASD. This master’s thesis is part of the epiFASD study at the Environmental Epigenetic Laboratory, University of Helsinki. The study focuses on the environmental impact on the epigenetic mechanisms of FASD and finding possible future biomarkers of early disease. The research group has collected biological samples from a cohort of control and alcohol exposed newborns and their parents. The main aim of the study is to reveal the effects of prenatal alcohol exposure to the epigenetic reprogramming of the newborn. If there are epigenetic fingerprints to be seen in the first developing cells of the embryo, these fingerprints may spread to other cells and tissues by cell proliferation. The main aim of this master’s thesis was to optimize a DNA extraction protocol for the collected buccal cell samples. The optimization was expected to enhance the concentration and purity of the DNA samples for future studies. The group had found earlier prenatal alcohol exposure associated changes on the DNA methylation of alcohol-exposed placentas by genome-wide microarrays. The second aim of the thesis was to observe if similar DNA methylation patterns are found in both buccal epithelial cells and placental tissue. The optimization of the DNA extraction protocol enhanced the concentration but not significantly the purity of the buccal cell DNA samples. The earlier microarray studies with placental tissue revealed an interesting candidate gene and the locus-specific EpiTYPER-analysis confirmed the results: the regulatory regions of the studied gene were less methylated in alcohol-exposed placentas compared to controls. EpiTYPER also showed that methylation levels of the placenta and buccal epithelial cells did not correlate with each other although the changes were similar. Further research needs to be done to confirm if the methylation changes could be used as biomarkers in the diagnosis of alcohol-related disorders.
  • Holla, Annele Jenni Tuulikki (2021)
    Binge eating disorder (BED) is a common eating disorder that includes eating a large amount of food in a short period of time and is often associated with obesity. Patients can suffer from stress, anxiety, and metabolic syndrome caused by the weight gain, but no effective medication for both psychological and physiological issues have been discovered. This thesis studies the potential of short-chain fatty acids (SCFA) in reducing binge-like eating behaviour in a mouse model that does not include food restriction. The model includes a 24 h bingeing period with high-fat food once a week. SCFA butyrate, propionate, and acetate were administered to mice via 1 g/kg i.p. injections or 200 mM drinking water for three days, and their effects on energy intake during the bingeing period were measured. The results show that SCFA can significantly reduce binge-like eating behaviour in mice in the short term, but long-term effects vary. I.p. butyrate, propionate, and acetate decreased energy intake by 68%, 57%, and 62% during the first hour, respectively. SCFA via drinking water did not decrease energy intake a lot, and the results were inconsistent between animals. These results suggest a potential for SCFA to attenuate bingeing episodes when administered acutely, but the mechanisms remain to be discovered.
  • Tallberg, Robert Georg Michael (2021)
    The immune system is crucial in the central nervous system (CNS), protecting sensitive tissues, promoting regeneration, and maintaining homeostasis. It is involved in CNS-disorders, such as neurodegenerative diseases and neurological insults related to stroke. Critical myeloid leukocytes in the CNS are microglia, divided into pro-inflammatory M1 and anti-inflammatory M2 phenotypes. This polarization achieves modulation of the inflammatory response by amplifying or dampening it. Therefore, microglia are widely investigated in CNS-disorders. β2-integrins are adhesion proteins that mediate inflammation. They are expressed explicitly on leukocytes, including microglia. Important processes, such as phagocytosis and cell motility, are regulated by β2-integrins. They also relay downstream signals, altering inflammation in many settings, although their effects on microglial properties and stroke are currently poorly understood. We here aimed to investigate the role of β2-integrins in stroke-related injury and microglia polarization in vivo using knock-in (KI) mice, which lack functional β2-integrins. Our results show that in a mouse model of haemorrhagic stroke, the functional outcome was less severe in β2-integrin KI versus wild-type (WT) mice (P = 0.0147), suggesting that β2-integrins are involved in stroke pathophysiology. Furthermore, by using flow cytometry we observed significantly lower frequencies of M1 microglia in the KI mouse brain (P = 0.0096). Therefore, our findings reveal neuroprotective aspects by inhibiting β2-integrins in neuroinflammation. Investigating microglial properties mediated by β2-integrins could contribute to the understanding of neuroinflammatory events, leading to the development of therapies for poorly treated CNS-disorders. Our results suggest that β2-integrins should be further explored as molecular targets for novel stroke treatments.
  • Feodoroff, Michaela (2020)
    Within the field of cancer immunotherapy, immune checkpoint inhibitors have been a revolution since they provoke re-activation of T-cell immune responses towards cancer. Despite their success, they only work in 13% of the patients because of a poorly immunogenic tumor, mostly due to weak T-cell infiltration. Oncolytic viruses have shown the ability to work in synergy with checkpoint inhibitors because of their tumour-specific tropism, innate immunogenicity and ability to secrete immunostimulatory agents into the tumor microenvironment. Regardless of the great potential, we lack suitable pre-clinical models to test this effect. In this study we developed renal cell carcinoma-derived organoids as in vitro platforms due to their high pre-clinical predictability compared to that of murine and in vitro 2-dimensional cell culture models. To test the ability of oncolytic viruses to stimulate the immune system, we generated three cytokine-expressing (CXCL9, CXCL10 and IL-15) oncolytic adenoviruses using a novel cloning method that we developed. We have shown that these viruses successfully produce high amount of the cytokine and attract peripheral blood mononuclear cells freshly isolated from Buffy coats. Genetically modified oncolytic adenoviruses were also shown to infect and kill human renal cell carcinoma organoids. Together, our results demonstrate the potential of organoids as test platforms for oncolytic virus -based therapy and the importance of adequate cytokine expression in T-cell recruitment. The tumor organoid platform we developed will be useful for advancing patient-specific treatment strategies and serve as a base for innovative immunotherapy models.
  • Sandvik, Martin (2022)
    Skeletal muscle is the most abundant tissue in the body, accounting for up to 40-50% of total bodyweight. Regeneration of this tissue is dependent on skeletal muscle stem cells, which are termed satellite cells (SCs) based on their anatomical position between the basal lamina and plasma membrane of muscle fibers. SCs exist under homeostatic conditions in a reversible G0 phase of the cell cycle. Quiescent SCs are recognized by the expression of the paired box 7 (Pax7) transcription factor, in the absence of other myogenic transcription factors such as myoblast determination protein 1 (MyoD) or myogenin (MyoG). Quiescent SCs are metabolically less active with a low oxygen consumption rate. They contain less ATP and have few mitochondria with a low membrane potential in comparison to activated SCs. Activated SCs enter the cell cycle and start to proliferate, undergoing metabolic rewiring to primarily utilize glycolysis for energy production. During early activation, there is an increase in mitochondrial content and ATP production, while the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) increase later during active proliferation. Although similar population dynamics, SCs are a heterogenous population of stem cells, with differences in the expression of notch receptors, stem cell markers, ATP and mitochondrial content, which in turn affect the myogenic potential of the cells. Mitochondria are semi-autonomous, double membrane organelles with various regulation within the cell, such as calcium homeostasis, apoptosis, production of metabolic intermediates, reactive oxygen species (ROS) metabolism, and ATP generation through oxidative phosphorylation (oxphos). Differentiation of various other stem cell types is accompanied by an increase in both mitochondrial content and oxidative phosphorylation, with ultrastructural changes that favour this shift in metabolism. The aim of this thesis was to quantify the ultrastructural changes that occur within SC mitochondria during the early proliferative phase, and to implement a method of Correlative Light and Electron Microscopy (CLEM) for identifying and studying subpopulations of SCs. After isolation and during early activation, SCs contain few mitochondria with a diffuse ultrastructure. Classification of the observed mitochondrial phenotypes revealed heterogeneity both within and between timepoints. During later phases of proliferation, there was an increase in the proportion of mature mitochondria, with an increase in cristae density and a decrease in cristae width. Utilizing genetically modified R26-Snaptag-Omp25 x PAX7CreErt2 mice in which recombination with tamoxifen initiates the expression of mitochondrial outer membrane protein 25 (omp25) bound with a SNAP-tag, allowed for specific and temporal labelling of SC mitochondria by fluorescent SNAP substrates. Performing CLEM on fluorescently labelled SC mitochondria enabled their identification during transmission electron microscopy (TEM). In addition to this, temporal labelling of pre-existing (old) and newly imported (young) omp25 revealed a few cells that contained more old mitochondria, with the cristae density being higher in these. While this indicates a correlation between mitochondrial content and ultrastructure within subpopulations of SCs, further studies are needed to validate these early observations.