System-level characterization of Th2 cell development and immune cell responses to ZnO and TiO2 nanoparticles

Asthma and allergy are common diseases and their prevalence is increasing. One of the hypotheses that explains this trend is exposure to inhalable chemicals such as traffi c-related air pollution. Epidemiological research supports this theory, as a correlation between environmental chemicals and allergic respiratory diseases has been found. In addition to ambient airborne particles, one may be exposed to engineered nanosized materials that are actively produced due to their favorable physico-chemical properties compared to their bulk size counterparts. On the cellular level, improper activity of T helper (Th) cells has been connected to allergic reactions. Th cells can differentiate into functionally different effector subsets, which are identifi ed according to their characteristic cytokine profi les resulting in specifi c ability to communicate with other cells. Th2 cells activate humoral immunity and stimulate eradication of extracellular pathogens. However, persistent predominance of Th2 cells is involved in a development of number of allergic diseases. The cytokine environment at the time of antigen recognition is the major factor determining the polarization of a naïve Th cell. Th2 cell differentiation is initiated by IL4, which signals via transcription factor STAT6. Although the importance of this pathway has been evaluated in the mouse studies, the signaling components involved have been largely unknown. The aim of this thesis was to identify molecules, which are under the control of IL4 and STAT6 in Th cells. This was done by using system-level analysis of STAT6 target genes at genome, mRNA and protein level resulting in identifi cation of various genes previously not connected to Th2 cell phenotype acquisition. In the study, STAT6-mediated primary and secondary target genes were dissection from each other and a detailed transcriptional kinetics of Th2 cell polarization of naïve human CD4+ T cells was collected. Integration of these data revealed the hierarchy of molecular events that mediates the differentiation towards Th2 cell phenotype. In addition, the results highlighted the importance of exploiting proteomics tools to complement the studies on STAT6 target genes identifi ed through transcriptional profi ling. In the last subproject, the effects of the exposure with ZnO and TiO2 nanoparticles was analyzed in Jurkat T cell line and in primary human monocyte-derived macrophages and dendritic cells to evaluate their toxicity and potential to cause infl ammation. Identifi cation of ZnO-derived gene expression showed that the same nanoparticles may elicit markedly distinctive responses in different cell types, thus underscoring the need for unbiased profi ling of target genes and pathways affected. The results gave additional proof that the cellular response to nanosized ZnO is due to leached Zn2+ ions. The approach used in ZnO and TiO2 nanoparticle study demonstrated the value of assessing nanoparticle responses through a toxicogenomics approach. The increased knowledge of Th2 cell signaling will hopefully reveal new therapeutic nodes and eventually improve our possibilities to prevent and tackle allergic infl ammatory diseases.

Eläinavusteinen lukutaidon interventio. Pilottitutkimus lukutilanteiden tapahtumien observoinnista sekä intervention vaikutuksesta 2.- ja 3.-luokkalaisten lasten lukumotivaatioon

Tutkimuksessa selvitettiin oikean koiran ja lelukoiran avulla toteutetun eläinavusteisen lukumotivaation intervention soveltuvuutta 2.- ja 3.-luokkalaisille lapsille sekä intervention vaikutuksia lukumotivaatioon. Tutkimukseen osallistui 16 lasta, joiden lukemaan oppiminen oli viivästynyttä ja jotka olivat opettajan ja vanhemman mukaan haluttomia lukemaan. Tutkimuksessa käytettiin satunnaisesti koe- ja kontrolliryhmiin jaettujen vertaistettujen parien asetelmaa. Lapset lukivat ääneen ikätasoon sopivaa kirjaa koiran ja ohjaajan tai lelukoiran ja ”ohjaajan” läsnä ollessa. Lukutilanne kesti noin 10 minuuttia ja lukukertoja oli lasta kohden yhteensä 13–15. Lapsilla oli lukemisen jälkeen mahdollisuus olla vuorovaikutuksessa koiran tai lelukoiran ja ohjaajan kanssa. Lukutilanteet videoitiin ja jokaiselta lapselta analysoitiin 8 lukutilannetta (58 %) video-observaatiolla. Lukutilanteet olivat varsin samanlaisia molemmilla ryhmillä. Koeryhmän lasten lukuajat olivat kuitenkin pidempiä kuin kontrolliryhmän lasten lukuajat. Oikean koiran käyttämisestä seurasi lukutilanteisiin luonnollisesti vaihtelua, toisin kuin lelukoiran käyttämisestä. Lisäksi koeryhmän lapset katsoivat koira-ohjaaja-pariin ja muualle lukutilaan enemmän kuin kontrolliryhmän lapset. Koeryhmän lapset olivat myös useammin vuorovaikutuksessa koiran kanssa lukutilanteen jälkeen kuin kontrolliryhmän lapset. Lapset, vanhemmat ja opettajat arvioivat lukumotivaation muuttuneen hyvin yksilöllisesti, eivätkä koe- ja kontrolliryhmien lukumotivaatiot eronneet ryhmätasojen vertailuissa. Kun tarkasteltiin kaikkien lasten lukumotivaatiota, vanhemmat arvioivat lasten lukumotivaation vahvistuneen intervention aikana.

Blackcurrant seed oil for prevention of atopic dermatitis

One hypothesis for the increased incidence of atopic diseases has been that it is associated with changing dietary habits, especially the changed intake of essential fatty acids (EFAs). The metabolism of EFAs produces eiconasoids, prostaglandins and leukotrienes, which are essential to organs and play a major role in regulation of inflammation and immune response. In some studies persons with atopic dermatitis have been found to have reduced levels of EFAs. The first year of infancy as well as the foetal period are crucial for the development of atopic immune response. The composition of blackcurrant seed oil (BCSO) corresponds to the recommended ratio of EFAs n-3 and n-6 in the diet (1/3-1/4) and as a dietary supplement could, even in small doses, modify the unbalance of EFAs in an efficient way. The purpose of this study was to find out whether atopic allergies can be prevented by supplementing the diet of pregnant mothers with blackcurrant seed oil and whether it could affect the immunological balance of a child. We also sought to find out whether a blackcurrant seed oil supplementation can affect the composition of breast milk to suppress the T helper 2 lymphocyte (Th2) responses in infants. 313 pregnant mothers were randomly assigned to receive BCSO (n=151) or olive oil as placebo (n=162). Supplementation was started at the 8th to 16th weeks of pregnancy, 6 capsules per day (dose of 3 g), and continued until the cessation of breastfeeding. It was thereafter followed by direct supplementation to infants of 1 ml (1 g) of oil per day until the age of two years. Atopic dermatitis and its severity (SCORAD index) were evaluated, serum total IgE was measured and skin prick tests were performed at the age of 3, 12 and 24 months. Peripheral blood mononuclear cell (PBMC) samples were taken at the age of 3 and 12 months and breast milk samples were collected during the first 3 months of breastfeeding. Parental atopy was common (81.7%) in the studied infants, making them infants with increased atopy risk. There was a significantly lower prevalence of atopic dermatitis in the BCSO group (33%) than in the olive oil group (47%) at the age of 12 months. Also, SCORAD was lower in the BCSO group than in the olive oil group. Dietary intervention with BCSO had immunomodulatory effects on breast milk, inducing cytokine production from Th2 to Th1 immunodeviation. It decreased the level of IL-4 and elevated the level of IFN-γ. BCSO intervention did not affect cytokines in the children’s PBMC. However, children of smoking parents in the combined BCSO and olive oil group had significantly elevated levels of Th2 type cytokines IL-4, IL-5 and the proinflammator cytokine TNF. Dietary supplementation with BCSO is safe. It is well tolerated and transiently reduces the prevalence of atopic dermatitis at the age of 12 months. It can possibly become a potential tool in prevention of atopic symptoms when used at the early stages of life.

School Bullies’ Quest for Power: Implications for Group Dynamics and Intervention

Bullying is characterized by an inequality of power between perpetrator and target. Findings that bullies can be highly popular have helped redefine the old conception of the maladjusted school bully into a powerful individual exerting influence on his peers from the top of the peer status hierarchy. Study I is a conceptual paper that explores the conditions under which a skillful, socially powerful bully can use the peer group as a means of aggression and suggests that low cohesion and low quality of friendships make groups easier to manipulate. School bullies’ high popularity should be a major obstacle for antibullying efforts, as bullies are unlikely to cease negative actions that are rewarding, and their powerful position could discourage bystanders from interfering. Using data from the Finnish program KiVa, Study II supported the hypothesis that antibullying interventions are less effective with popular bullies in comparison to their unpopular counterparts. In order to design interventions that can address the positive link between popularity and aggression, it is necessary to determine in which contexts bullies achieve higher status. Using an American sample, Study III examined the effects of five classroom features on the social status that peers accord to aggressive children, including classroom status hierarchy, academic level and grade level, controlling for classroom mean levels of aggression and ethnic distribution. Aggressive children were more popular and better liked in fifth grade relative to fourth grade and in classrooms of higher status hierarchy. Surprisingly, the natural emergence of status hierarchies in children’s peer groups has long been assumed to minimize aggression. Whether status hierarchies hinder or promote bullying is a controversial question in the peer relations’ literature. Study IV aimed at clarifying this debate by testing the effects of the degree of classroom status hierarchy on bullying. Higher hierarchy was concrrently associated with bullying and predictive of higher bullying six months later. As bullies’ quest for power is increasingly acknowledged, some researchers suggest teaching bullies to attain the elevated status they yearn for through prosocial acts. Study V cautions against such solutions by reviewing evidence that prosocial behaviors enacted with the intention of controlling others can be as harmful as aggression.

Percutaneous Coronary Intervention in Patients with Atrial Fibrillation: A Study of Factors Affecting Outcome, with a Special Emphasis on Periprocedural Antithrombotic Treatment

Antithrombotic treatment of patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) is a delicate balancing between the risk of thromboembolism and the risk of bleeding. The purpose of this dissertation was to analyze current antithrombotic treatment strategies at the periprocedural stage and report outcomes in-hospital and at 1-month follow-up, and to evaluate the effect of renal impairment and predictive values of various bleeding scores on 1-year outcome after PCI in patients with AF. The first article was based on retrospective data from 7 Finnish hospitals between 2002–2006 (n=377), while the others were based on a prospective 17-center European register (AFCAS) gathered between 2008–2010 (n=963). The main findings in patients with AF undergoing PCI were: The use of glycoprotein IIb/IIIa inhibitors during PCI was associated with a four- to five-fold increase in the risk of major bleeding (I). Uninterrupted warfarin treatment did not increase perioperative complications and seemed to decrease bleeding complications compared to heparin bridging (II). Already mild renal impairment (eGFR 60–90mL/min) was associated with a 2.3-fold risk of all-cause mortality during the 12 months following PCI (III). Major adverse cardiac events occurred in 4.5% and bleeding complications in 7.1% of patients in the AFCAS register by 1-month follow-up (IV). In a study of patients in AFCAS register, all currently used bleeding risk scores were poor predictors of bleeding complications by 1-year follow-up (V). The findings will help improve treatment strategies for this fragile patient population with a high risk of bleeding and thrombotic complications.