Faculty of Medicine


Recent Submissions

  • Laine, Hanna (Helsingin yliopisto, 2021)
    Salivary gland cancer (SGC) comprises less than 5% of head and neck malignancies. Adenoid cystic carcinoma (ACC) is denoted as the second most common SGC worldwide. In Finland, ACC is the most common histological subtype according to a nationwide study. ACC is a slow-growing neoplasm and has a tendency for perineural invasion. ACC shows three distinct histological growth patterns: cribriform, tubular, and solid. Surgery is the pivotal treatment modality, but treatment is modified according to tumor site, biological aggressiveness, and stage of the disease, which is determined according to the Union for International Cancer Control (UICC) Tumor-Node-Metastasis (TNM) classification. Postoperative radiotherapy is recommended for all patients, but chemotherapy is used mainly for inoperable, recurrent, or metastatic disease. Recurrencies affect approximately 50% of patients. Especially local and distant recurrent tumors are fairly common, with distant metastasis being more frequent and lungs the most common site. ACC has a good 5-year disease-specific survival (76-88%), but the 10-year survival (34-67%) is clearly worse. Prognostic factors affecting survival are tumor site, TNM classification, histology, surgical margin status, and distant metastasis. In this thesis, the goal was to collect all patient data and tumor samples of the minor salivary gland ACC patients diagnosed between years 1974 and 2012 in the Helsinki University Hospital area. Patient and tumor characteristics, treatment, outcome, and their associations were studied. To evaluate the viral role in ACC samples, the presence of three polyomaviruses were assessed genotyping of 24 human papillomaviruses (HPV) was performed. Furthermore, by immunohistochemistry matrix metalloproteinase (MMP)-7, -8, -9, -15, and -25 and antizyme inhibitor (AZIN) 1 and 2 in ACC were studied. The most common tumor site was the palate. Of patients, 94% were treated with curative intent. Moreover, 53% of patients suffered from recurrent ACC of which 36% were local, 12% regional, and 52% distant. Almost all distant metastases appeared within 10 years. The 5- and 10-year overall survival and disease-specific survival were 70% and 79%, and 42% and 52%, respectively. Stage I ACC patients had better survival than patients with higher stages (II-IV). Of interest, John Cunningham polyomavirus (JCPyV) DNA was found in 10% of the tumor samples. In the immunohistochemical studies on MMPs, abundant MMP-7 and -25 were associated with better survival. High tumorous MMP-9 associated with advanced stage and high MMP-15 immunoexpression with poorer survival. Intriguingly, abundant MMP-9 immunoexpression in inflammatory cells in the vicinity of ACC and in luminal material of pseudocysts of ACC associated with better survival and fewer local recurrent tumors. Immunoexpression of AZIN2 was abundant in well-differentiated tumor tissue (cribriform and tubular), but in the solid pattern the expression was negative or mild. AZIN2 immunoexpression associated with better survival. To conclude, these results show that especially stage II ACC should be considered as advanced disease and patients would benefit from more aggressive treatment. Follow-up time should be prolonged for at least ten years. JCPyV could participate in the pathogenesis of a small proportion of ACC. MMPs could participate in ACC carcinogenesis by tissue modulation, activating different signaling pathways, and by immunomodulation. MMP-7, -9, -15, and -25 are related to prognostic factors. High AZIN2 immunoexpression in well-differentiated ACC could be related to a functioning vesicle transport system of tumor cells that no longer exists in poorly differentiated ACC tissue. AZIN2 could be a prognostic factor for better survival of ACC patients.
  • Silén, Yasmina (Helsingin yliopisto, 2021)
    Background and aims: Eating disorders are severe mental health issues that undermine psychological and physical health and quality of life. This thesis aimed to investigate the occurrence of eating disorders in a community sample of adolescents and young adults. Eating disorders were defined using the Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). A second major aim was to describe how often individuals with eating disorders were detected and received treatment and what kind of treatment was offered. Finally, the natural course and outcome of different subcategories of eating disorders were also examined. Methods: The study used two population-based Finnish twin datasets and one clinical dataset. FinnTwin12 followed all twins born in Finland between 1983 and 1987, whereas FinnTwin16 followed all twins born between 1975 and 1979, from adolescence to adulthood. From the FinnTwin12 data, we studied the occurrence, detection and treatment of eating disorders in health care and the natural course of these diseases. From the FinnTwin16 data, we examined the effects of diagnostic changes on the occurrence and prognosis of anorexia nervosa. From the clinical data of the Helsinki and Uusimaa Hospital District (HUS) Adolescent Psychiatry Eating Disorders Unit, we examined the treatment and prognosis of adolescents with typical and atypical anorexia nervosa. In all studies, we analysed the outcome of eating disorders using survival analysis. Results: Eating disorders were common. Up to one in 6 females and 1 in 40 males had suffered from an eating disorder during their development towards adulthood. Changes in diagnostic criteria increased the lifetime prevalence of anorexia nervosa by more than half and increased diagnostic heterogeneity. Overall, anorexia nervosa and related subthreshold symptoms were prevalent among females: One in 10 young women had suffered from a restrictive eating disorder by early adulthood. We also found that eating disorder symptoms in a community setting were diverse, and many reported eating disorder symptoms that could not be clearly labelled. This was particularly true among boys and men. Many individuals with eating disorders also described an unmet need for care; healthcare professionals diagnosed only one-third and even fewer received treatment. In addition, eating disorder symptoms were highly persistent: Five years after disease onset, less than two-fifths of the females and two-thirds of the males had recovered. The likelihood of recovery was similar between those who had and who had not received treatment, but more severe cases were more likely to receive treatment. Conclusions: Overall, this thesis showed that eating disorders are common, and their symptoms are highly diverse among Finnish adolescents and young adults. Considering the magnitude of the problem, detection and treatment approaches for eating disorders are still inadequate and mainly focused on typical presentations of eating disorders. In addition, eating disorder symptoms often persisted for years. Future research should determine how the prevention and detection of eating disorders could be improved in Finland. The threshold for access to treatment should also be lowered, and additional interventions should be developed. Future studies should investigate whether these actions could eventually lead to better outcomes.
  • Tuomainen, Katja (Helsingin yliopisto, 2021)
    Head and neck cancer (HNSCC) is the 8th most common cancer globally. Despite improved therapy, the 5-year survival rate has remained stagnant, at approximately 50%. Current preclinical in vitro anticancer compound testing features a low predictive value. Traditionally, in vitro cancer cell studies are conducted on a plastic surface or using animal–derived extracellular matrices, thereby overlooking the important interaction between cancer cells and the human tumor microenvironment. To overcome this problem, we have developed a human tumor leiomyoma–derived matrix Myogel. The aim of this PhD project was to develop reliable in vitro methods for anticancer drug testing by providing a human TME for HNSCC cells. The first approach was to investigate whether the use of a Myogel matrix could improve the reliability of drug screening compared to conventional plastic or the typically applied mouse sarcoma–derived matrix, Matrigel. We applied a high-throughput drug screening (HTS) to test 19 anticancer compounds, targeting EGFR, MEK, or PI3K/mTOR on 12 HNSCC cell lines under five different culturing conditions; cells on a plastic surface and on top of or embedded in Myogel or Matrigel. We found that cells cultured in Myogel were less sensitive to the EGFR and MEK inhibitors than cultured in Matrigel or on plastic. Additionally, Myogel cultured cells reflected better the response rates of EGFR inhibitor clinical trials compared to the other cultures. Therefore, we concluded that Myogel improves the predictability of in vitro anticancer drug testing compared to the plastic and Matrigel. Next, we performed a high-throughput drug screen to identify synergistic combinations using a compound library (n=396) and irradiation using HNSCC cell lines cultured on Myogel. The Bcl-2/Bcl-xL inhibitor navitoclax, which emerged as the most promising radiosensitizer, exhibited a synergy with irradiation in 13 HNSCC cell lines. Additionally, the navitoclax–irradiation combination halted the cell cycle and increased the irradiation-induced apoptosis. Overall, we demonstrated that the navitoclax–irradiation combination resulted in strong synergistic antitumor effects in HNSCC cell lines, and thereby it might possess therapeutic potential for HNSCC patients. The third, we manufactured a fully human in vitro microfluidic chip assay to test immunotherapeutic agents for personalized medicine purposes for HNSCC patients. First, the assay was run using the oral tongue cancer cell line (HSC-3) embedded in a Myogel–fibrin mixture and immune cells, isolated from healthy blood samples. After successful testing, the chip was applied for freshly isolated patent cells. Immune checkpoint inhibitors, IDO1 inhibitor (NLG-919) and a PD-L1 antibody were applied to chips and the immune cell migration and cancer cell proliferation were measured over three days. We found that the immune cell migration was associated with cancer cell density. The IDO1 inhibitor increased the immune cell migration towards cancer cells in HSC-3 and in two patient samples. In the future, this assay could possibly be utilized to predict an individual patient’s immunotherapy response against HNSCC.
  • Storvall, Sara (Helsingin yliopisto, 2021)
    Primary hyperparathyroidism (PHPT) is most commonly caused by benign tumors of the parathyroid glands, parathyroid adenomas (PA). Only about 1% of PHPT cases are due to parathyroid carcinoma (PC). In Finland, 2-3 new PC cases are diagnosed every year. The only curative treatment of PC is surgery. The diagnosis of PC is based on one criterium only: invasiveness, either on histopathological examination, or in the presence of metastases. This means that the diagnosis can only be set after surgery. Profusely high levels of calcium and parathyroid hormone (PTH) in the blood are more common in malignant disease than benign, but there is a significant overlap between the tumor groups. Atypical parathyroid adenomas (APA) are tumors that share histological properties with PC but lack the invasive characteristics that define malignancy. This is a largely unknown disease entity, and it is not entirely sure to which extent APAs behave indolently like PA, and to which extent they cause a more aggressive cause of disease. Recurrence occurs in roughly half of all PC cases. In inoperable or disseminated disease, there are only palliative treatment options, as chemotherapy or radiotherapy are not effective. With this thesis, we aimed to improve the diagnostics of parathyroid carcinoma: We wanted to find tissue markers that could help in the diagnostic process, or markers that could give a hint on the prognosis of the patient. We also wanted to investigate potential treatment options in inoperable PC. Our material consists of a nationwide cohort of all PC tumors diagnosed in Finland between the years 2000-2011, and additional PC tumors from the Helsinki University Hospital district diagnosed after that as well as APA and PA tumors, also from the Helsinki University Hospital District. Apart from tumor material, we also have extensive clinical data on these patients. We investigated the expression of somatostatin receptors (SST) 1-5 in parathyroid tumors by immunohistochemistry and found that all SST:s 1-5 were expressed to varying degree, and that the expression was increased in malignant tumors compared to benign. Furthermore, we investigated expression of the calcium-sensing receptor (CaSR) as well as the calcium-sensing receptor regulating protein Filamin A (FLNA). All tumors showed positive expression of CaSR. High expression of FLNA was significantly more common in PC tumors compared to benign. We combined the FLNA results with expression of the established parathyroid tumor marker parafibromin and found that tumors with low expression of FLNA that are parafibromin positive are highly likely to be benign or have an indolent course of disease. We also describe a patient case; the patient had disseminated PC with metastases in her bones and mediastinum. She was treated with a combination of the chemotherapy drug temozolomide (TEM), as well as surgery, radiotherapy, and calcium-lowering agents. The patient’s symptoms improved, and her disease progress halted. Ten years later, she is still in remission. For this case study, we investigated methylation of the MGMT gene in the patient’s tumor DNA: inactivation of MGMT by methylation is a prerequisite for successful treatment with TEM. We found that this patient’s methylation levels were high, which supports the role of TEM in the excellent treatment result. We then investigated MGMT methylation in a larger cohort of PC and APA patients. The case report patient was the only one with high MGMT methylation status, which indicates that MGMT methylation is rare in PC.
  • Nurmi, Anna (Helsingin yliopisto, 2021)
    Pancreatic cancer is one of the deadliest cancers, with a dismal 5-year overall survival rate ranging from 2% to 8%. Pancreatic ductal adenocarcinoma (PDAC) represents >90% of exocrine pancreatic malignancies and has the poorest survival rate. The dismal survival is due to the aggressive disease nature, frequently advanced disease stage at diagnosis, high recurrence rates, and the lack of effective oncological treatments. Margin-negative resection in combination with oncological treatment is the only curative treatment option. However, only 10% to 20% of the patients appear operable. Preoperative oncological therapy, neoadjuvant therapy, can downstage the disease to resectable and increase the proportion of margin-negative resections. The administration of neoadjuvant therapy has increased during the past decades. However, with inconclusive therapeutic responses, the administration of neoadjuvant therapy is still controversial in terms of patient selection. Inflammation has been reported to play a crucial role in tumor advancement. Systemic inflammation has been studied in various gastrointestinal cancers, and high C-reactive protein (CRP) correlates with a grim prognosis. In addition, local inflammatory markers, as shown by immunohistochemistry, have been widely applied in cancer research. Immunohistochemical stainings give insight into the tumor microenvironment, glandular tissue, expression, and, in this case, effects of neoadjuvant therapy. Investigating the surgical tissue specimen may give information on the treatment effect and help go towards patient-specific treatment options. The studies in this thesis explored the benefits of neoadjuvant therapy and which patients benefit from it. Additionally, the studies examined the relationship between inflammation and pancreatic cancer and searched for possible changes in the tumor and systemic inflammation patterns due to neoadjuvant therapy. Finally, the studies investigated prognostic factors for patients treated with neoadjuvant therapy. These studies found that neoadjuvant therapy is especially beneficial for borderline resectable patients with advanced disease stage and poorly differentiated tumor histology. The survival of borderline resectable patients has increased over the past two decades. Additionally, local immunological expression intensities differ between patients treated with neoadjuvant therapy and those undergoing upfront surgery. Furthermore, a preoperative prognostic score of CRP and CA19-9, a commonly used tumor marker in pancreatic cancer, was created to aid in the preoperative assessment of pancreatic cancer patients. With low preoperative CRP and CA19-9, patients survived multiple times longer than with elevated levels. Additionally, this study discovered that the decrease in CRP and CA19-9 during neoadjuvant therapy predict better postoperative survival.
  • Rinta-Kokko, Hanna (Helsingin yliopisto, 2022)
    The direct and indirect effects of pneumococcal vaccination on an individual and the population are of great interest. This study focuses on the definition, estimation and interpretation of different effect measures of vaccines and vaccination against pneumococcal colonisation and disease. Vaccine efficacy, effectiveness and impact are considered as epidemiological parameters of interest which are estimated using observations gathered according to some study design. In this thesis, vaccine efficacy against colonisation is defined through pneumococcal acquisition, which describes the natural process of incident occurrences of colonisation better than prevalence. Moreover, a general definition of vaccine efficacy against a multi-type pathogen is presented, with an epidemiologically meaningful interpretation as a weighted average of strain-specific efficacies. A feasible estimation method is then proposed, based on cross-sectional measurement on the current status of colonisation. When the differences in times at-risk between vaccinated and unvaccinated individuals are taken into account, the estimation of vaccine efficacy against colonisation is shown to be less biased by within-host competition between different serotypes (strains). The estimation method is exemplified with empirical data of pneumococcal colonisation in Israeli children. At the population level, vaccine effectiveness is the measure of vaccine-induced protection during an ongoing vaccination programme when both vaccinated and unvaccinated individuals experience the indirect effects of the vaccination programme. Vaccine impact is the population prevented fraction of the incidence of infection when exposure is the vaccination programme rather than each individual’s own vaccination. Both vaccine effectiveness and impact are parameters that depend on the population dynamics of pneumococcal colonisation and disease after vaccine introduction. In this thesis, the time trends of vaccine effectiveness and impact are described with a pseudo-dynamic model that incorporates the incidences of pneumococcal carriage and disease. The model shows that the effectiveness and impact against vaccine-serotype invasive pneumococcal disease (IPD) are expected to be high and largely of the same magnitude through the post-introduction period. By contrast, the vaccine effectiveness and impact against non-vaccine-serotype IPD follow very divergent paths while the vaccine-type colonisation and disease become eliminated. The practical estimation of vaccine effectiveness is exemplified with register data of Finnish children eligible for pneumococcal conjugate (PCV10) vaccination. Three parallel study designs, the cohort, nested case-control and indirect cohort designs, are shown to provide estimates that are broadly concordant with each other. The parameters of vaccine efficacy as proposed in this thesis can be interpreted as measures of the biological effect of the vaccine on new vaccine-type acquisitions and should therefore allow more robust comparisons across different epidemiological settings with differing levels of exposure by non-vaccine strains. Moreover, the thesis helps to interpret the time-varying parameters of vaccine impact and effectiveness during large-scale vaccinations, and their manifestation in Finnish children.
  • Filppu, Pauliina (Helsingin yliopisto, 2021)
    Glioblastoma (GBM), the most common and malignant primary brain tumor in adults, is among the most difficult cancers to treat with a median survival of only 15 months. GBMs are highly complex tumors with several unique features explaining the lack of effective therapies: infiltrative growth of the tumor cells prevents complete surgical removal of the tumor, the blood-brain barrier (BBB) effectively inhibits drug delivery to the tumor site, and identification of subpopulations of glioma stem cells (GSCs) that are an important source of cellular heterogeneity and therapeutic resistance. Novel therapeutic approaches for treatment of these devastating tumors are urgently needed. In this study, we investigated the molecular mechanisms underlying tumor initiation, progression, and therapy resistance of malignant human GBM. We aimed at identifying vulnerabilities that could potentially provide novel therapeutic targets for treatment of GBM. We utilized patient-derived GSC cultures and patient-derived xenograft tumors as models to study GBM. In the first study, we demonstrated that mammary-derived growth inhibitor (MDGI), also known as heart-type fatty acid binding protein 3 (H-FABP/FABP3), was not only highly expressed but also played a significant role in GBM invasion. We identified a novel function for MDGI in maintaining the lysosomal membrane integrity. Unexpectedly, GBM cells were extremely vulnerable to silencing of MDGI expression. We demonstrated that MDGI silencing caused lysosomal membrane permeabilization (LMP), which is an alternative cell death pathway leading to irreversible apoptosis. LMP can be induced by pharmacological agents such as antihistamines. Interestingly, we demonstrated that treatment of patient-derived xenograft tumors with antihistamine clemastine effectively eradicated the invasive tumor cells and prolonged animal survival in a preclinical study in vivo. In the most invasive patient-derived GBM model, treatment with clemastine led to a complete eradication of the tumor. Our results encourage testing clemastine in a clinical trial of patients with GBM. In the second part of this study, we provided important insight into GSC plasticity driving tumorigenesis and therapy resistance of GBM. We identified a molecular mechanism where CD109 physically interacts with glycoprotein 130 (GP130) to regulate the interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling pathway. We further demonstrated that the CD109/STAT3 axis was essential for the maintenance of stemness and plasticity of GSCs. When CD109 was silenced, GSCs differentiated into astrocytic-like cells and were unable to dedifferentiate into the stem-like state. Moreover, the CD109/STAT3 axis was needed for the tumorigenicity of patient-derived xenograft models in vivo. Importantly, genetic targeting of CD109 and pharmacologic inhibition of STAT3 both sensitized the GSCs to chemotherapy. These results suggest that therapeutic targeting of CD109/STAT3 axis in combination with chemotherapy might potentially increase the effect of chemotherapy in patients with GBM and help to overcome the therapy resistance. This study provides important insight into novel disease mechanisms with potential therapeutic implications for GBM patients.
  • Lassander, Maarit (Helsingin yliopisto, 2021)
    Mindfulness is a capacity to focus on present-moment awareness that can be enhanced and learned. Studies I and II examined the outcomes of mindfulness intervention on resilience, depressive symptoms, socioemotional functioning (primary outcomes) and health-related quality of life (secondary outcome). Finnish school children and adolescents (N=3519) aged 12–15 years (6th to 8th graders), from 56 schools, were cluster-randomised into a 9-week mindfulness intervention group or control groups with a relaxation program or teaching as usual. In Studies III and IV, a subset of students (N=131) completed a cognitive test-package to measure executive functioning, and a majority of these students (N=110) also completed the psychophysiological test-package to measure stress reactivity. All measures were completed at baseline, at completion of the programs at 9 weeks, and at follow-up at 26 weeks. In Study I, the mindfulness intervention did not show more beneficial effects on the primary outcomes compared to the controls, except for resilience for which a positive intervention effect was found at 9 weeks in the whole intervention group compared to the active control group. In addition, in gender- and grade-related analyses, the intervention reduced the prevalence of depressive symptoms in girls, and the effect was also significantly different compared to boys. The mindfulness intervention improved socioemotional functioning among 7th graders at 9 weeks and 26 weeks, compared to the active control group. In Study II, a significant intervention effect was found for health-related quality of life at 9 weeks and 26 weeks as compared to the active control group. Moderating effects were found for both gender and grade. Girls and 7th–8th grade students benefited most from the intervention in terms of health-related quality of life compared to the active control group. In the subset of students in Study III, both the intervention group and active control group improved on a majority of executive functioning measures (response inhibition, cognitive processing and flexibility, verbal fluency) at both 9 weeks and 26 weeks. In Study IV, the number of electrodermal responses indicative of stress stayed at the same level in the intervention group, but increased in the active control group, during a task of social stress at both the 9 week and 26 week follow-ups, suggesting that mindfulness may have a stress buffering effect in the intervention group. In sum, this thesis contributes to the field of mindfulness and socioemotional learning by showing the potential benefits of short-term mindfulness intervention for wellbeing outcomes in adolescents. The results of this thesis can be applied in adapting and targeting mindfulness interventions in schools to achieve optimal benefits.
  • Louhivuori, Verna (Helsingin yliopisto, 2021)
    Neural stem cells and their arising progenitors create our central nervous system (CNS). The questions of how neural progenitor cells (NPCs) are determined to a certain neuronal fate, in that, how do they mature, migrate, and develop to take on their physiological roles, during the formation of functional networks in the brain, remain fundamentally unanswered. Despite the vast amount of information acquired and accumulated over the last centuries, the interplay between molecular mechanisms that drive brain development have only recently started to unravel. Studies have shown that early brain electrical activity, neurotransmitter-induced responses, and trophic factor signaling, acting through their respective receptors, are implicated as critical regulators of brain development. By elucidating the mechanisms governing progenitor cell behavior under normal and pathological conditions, such as fragile X syndrome (FXS), the most common cause of intellectual disability and leading genetic cause of autism, will further improve our understanding of brain development, and facilitate the development of CNS cell therapies. This thesis aims to shed light into the molecular and cellular mechanisms in the developing brain by utilizing in vitro neurosphere model to study the differentiation and migration of neural progenitors, by combining gene and protein expression analysis, and immunocytochemical stainings with intracellular calcium imaging and time-lapse video microscopy. In addition, in vivo immunohistological staining methodologies, in situ hybridization studies and in utero electroporation were utilized to study neocortical development in the absence of functional Fragile X mental retardation protein (FMRP), in a mouse model for FXS. Taken together, results presented in this thesis provide new information on the molecular mechanisms that guide neural progenitor cells and their interactions with radial glia (RG) cells. It sheds key insights into NPC functional responses as they mature and differentiate, identifying key molecular players as well as providing compelling evidence that neural-glia interaction during cortical formation plays an important role in brain development. Additionally, timing, and region-specific modulatory role of brain-derived neurotrophic factor (BDNF)-TrkB signaling during neocortical development and abnormalities particularly in glutamatergic neurogenesis in the absence of FMRP was demonstrated.
  • Sirén, Maria (Helsingin yliopisto, 2021)
    Background: Shoulder diseases are common among working populations, especially among manual workers. Symptomatic shoulder lesions predominantly manifest as pain while loading and abducting the arm, which often continues at rest. Shoulder pain is known to cause disability, absences from work and significant healthcare costs. Because the pathomechanisms of most shoulder lesions are degenerative, they become more prevalent with age and usually affect individuals in the middle or latter part of their working careers. However, little is known about how a shoulder lesion impacts work participation or how prolonged work disability due to a shoulder lesion could be prevented. Aims: The first objective of this thesis study was to examine the impact of a disabling shoulder lesion on work participation and working life expectancy. Further objectives were to identify the occupational risk factors as well as the occupations with a high risk of disability retirement due to a shoulder lesion. The final aim was to determine the associations of lifestyle factors and cumulative workload factors with SA due to a shoulder lesion. Methods: Studies I–III used large, nationwide, administrative register data enriched with occupation-specific information on work-related factors. Cohorts, which were formed from a 70% random sample of individuals aged 18–70 living in Finland, were followed for nine to ten years. The cohort of Study IV was nationally representative and consisted of participants of the Finnish Health 2000 Survey. This cohort was followed for 15 years. Results: People with prolonged SA due to a shoulder lesion lost a considerable number of their potential working life years, mainly due to preterm old-age retirement and disability retirement. Among both genders, physically heavy work showed the strongest association with disability retirement due to a shoulder lesion. Altogether, physical workload factors explained 46% and 41%, and psychosocial work-related factors 49% and 41% of disability retirement due to a shoulder lesion among men and women, respectively. The risk of disability retirement due to a shoulder lesion was generally higher in manual occupations and heavy physical work significantly explained the excess risk in most of the occupations. Risk factors for SA due to a shoulder lesion included being exposed for at least ten years to physically heavy work, being exposed for more than ten years to at least two specific physical workload factors, and daily smoking. In addition, obesity was a risk factor among men. The modifiable risk factors explained 60% of SA among men and 49% among women. Conclusions Work participation is notably reduced among people with prolonged SA due to shoulder lesion. Reducing work-related factors to a low level has great potential to prevent disability retirement due to shoulder lesions. Avoiding regular cumulative exposure to physical workload factors also showed potential to prevent SA due to a shoulder lesion.
  • Jäntti, Toni (Helsingin yliopisto, 2021)
    Cardiogenic shock is the most severe form of acute heart failure. It is a syndrome in which an initial insult results in deterioration of cardiac output, leading to systemic hypoperfusion often with accompanying microcirculatory dysfunction and systemic inflammatory responses resulting in organ injury and high mortality. Despite modern advanced therapies, short-term mortality in cardiogenic shock remains high at approximately 40%. Mortality in cardiogenic shock is often caused by multi-organ failure, but the incidence, sequence and predisposing factors for organ injury and impairment in cardiogenic shock patients remains largely unstudied. Novel invasive therapies, such as mechanical circulatory support devices may be life-saving in certain situations but also carry a high risk of complications, increasing the need for risk assessment tools for selection of suitable patients while avoiding harm and futility. The aim of this thesis was to investigate biomarkers associated with end-organ injury in cardiogenic shock, to assess the incidence of organ injury, and to assess the prognostic importance of the biomarkers in cardiogenic shock patients. The study population was 179 patients enrolled in the multinational, prospective, observational CardShock study with blood samples available. Study I evaluated the prevalence and prognostic importance of several liver biomarkers and their early changes within the first 24 hours of study enrolment. We found that although elevated alanine aminotransferase (ALT) was frequent already at baseline, it was not independently associated with 90-day mortality, whereas an early increase in ALT by 20% or more within the first 24 hours was strongly and independently associated with higher 90-day mortality. Findings in study I suggest that early increases in ALT in patients in cardiogenic shock are related to organ hypoperfusion, which was supported by the association of ALT increase with lower cardiac index and other clinical markers of hypoperfusion. Study II assessed albumin levels in cardiogenic shock patients and their association with 90-day mortality. Hypoalbuminemia was present in 75% of patients in the early phase of cardiogenic shock. Hypoalbuminemia was associated with pre-existing comorbidities, higher levels of C-reactive protein and lower levels of hemoglobin. Plasma albumin levels at baseline were independently associated with 90-day all-cause mortality, with mortality increasing across lower albumin quartiles in a linear fashion. Study III investigated two biomarkers – plasma proenkephalin (P-PENK) and plasma neutrophil gelatinase-associated lipocalin (P-NGAL) – which have previously been shown to be associated with acute kidney injury (AKI). Levels of both P-PENK and P-NGAL differed between patients who did and did not develop AKI defined by an increase in creatinine within 48 hours (AKIcrea48h) as well as between 90-day survivors and nonsurvivors. High baseline levels of both P-PENK and P-NGAL were able to predict the occurrence of AKIcrea48h with reasonable accuracy. High levels of P-PENK and P-NGAL at 24 hours were independently associated with increased 90-day all-cause mortality after adjustments for AKIcrea48h and two risk scores validated for cardiogenic shock patient populations. Study IV examined the associations of a novel biomarker, circulating miR-423-5p, with clinical findings, other biomarkers and outcome. Above median levels of circulating miR-423-5p were associated with markers of hypoperfusion, organ injury and dysfunction. A miR-423-5p level above median also predicted 90-day mortality independently of established risk factors in cardiogenic shock patients. The association of miR-423-5p with high-sensitivity troponin T, an established marker of cardiac injury, depended on the etiology of cardiogenic shock. In conclusion, the studied biomarkers (ALT, albumin, P-PENK, P-NGAL and miR-423-5p) relate to organ injury, provide additional prognostic information compared with clinical risk scores and can be utilized in the risk assessment of patients in cardiogenic shock.
  • Zhao, Zhe (Helsingin yliopisto, 2021)
    By July 17, 2021, the human immunodeficiency virus (HIV) has claimed more than 36.3 million lives worldwide. Currently, an estimated 38 million people are living with HIV. Although 67% of these infected individuals (approximately 25 million people) have been receiving antiretroviral therapy (ART), and 59% (around 22 million) have successfully suppressed the HIV replication with no risk of spreading to others, still, 10-40% of such aviremic HIV patients are suffering from persistent inflammation. Such chronic immune activation contributes to HIV-associated neurocognitive impairment, resulting in loss of life quality during ageing. This thesis addresses the mechanisms of the proinflammatory effector TACE secretion into extracellular vesicles (EVs) triggered by HIV accessory protein Nef. Such TACE-containing circulating EV levels are associated with low CD4+ T cell counts in aviremic HIV patients. In addition, the results reveal that HIV-1 Nef activates Src family kinase member Hck to promote the EV packaging of TACE, and such TACE secretion utilizes an unconventional Golgi bypass route. Moreover, this thesis unveils the roles of the Raf-MEK-ERK kinase cascade in HIV-induced TACE secretion. Clinically approved MEK inhibitors could suppress HIV-driven EV packaging of TACE significantly. Lastly, this study identifies a molecular structure in Nef, termed “R-clamp,” playing a pivotal role in the SH3 domain-mediated interaction between Nef and Hck. This thesis supplies evidences supporting a hypothesis that the Nef protein of HIV-1 is involved in HIV-induced chronic immune activation. Besides, this study offers a potential novel strategy for treating such HIV-associated immune activation.
  • Berntzen, Bram (Helsingin yliopisto, 2021)
    Obesity is a complex global health concern, associated with biological, social, psychological, and environmental factors. Obesity increases the risk of comorbidities, such as cardiovascular diseases, type 2 diabetes, and forms of cancer. To reduce the global burden of obesity, we require further understanding of its determinants. Physical inactivity, unhealthy eating behaviors, and curtailed sleep have been associated with higher body weight. However, most studies have been unable to control for the confounding influences of genotype and early life environmental factors. This research project aimed to understand how physical activity (PA), eating, and sleep behaviors were associated with body mass index (BMI), adiposity, and metabolic health, independent of genotype and early environmental factors (together “familial” influences). I, together with the research group I belong to, secondarily tested how sleep associated with PA and eating behaviors, because an interconnection between these behaviors is plausible. To overcome confounding by familial factors, we investigated healthy (except for obesity) Finnish monozygotic (MZ) twin pairs (Studies I, II, III) who share personal factors (e.g., age, sex, and 100% of the DNA sequence) and have shared environmental factors during early life (e.g., in utero, family, and neighborhood environment). We also investigated same-sex dizygotic (DZ) twin pairs who share the same factors, except their segregating genes (only ~50% overlap). This thesis focused on twin pairs who varied strongly in BMI within pairs (BMI difference of at least 3 kg/m²). We screened 5,417 young adult (22–36 y) twin pairs from ten full birth cohorts to acquire 36 MZ and 46 same-sex DZ twin pairs discordant for BMI (∆BMI ≥ 3 kg/m²). A random sample of twin pairs (38 MZ and 31 same-sex DZ twin pairs) participated as BMI-concordant twin pairs (∆BMI < 3 kg/m²). This thesis incorporated three cross-sectional studies performed under natural conditions. Study I addressed the twins’ PA derived from self-reports and hip-worn actigraphy and cardiorespiratory fitness from spiroergometry, Study II investigated self-reported eating behaviors, and Study III assessed sleep behaviors acquired with questionnaires and wrist-worn actigraphy. All studies included clinical measurements of BMI, adiposity (e.g., adipose tissue mass and location), and metabolic health variables (e.g., insulin sensitivity, cholesterol, and inflammation). Study I found that in the MZ BMI-discordant twin pairs, the heavier co-twins took fewer steps daily, performed shorter daily moderate-to-vigorous intensity PA (MVPA), and reported less activity through sports, but no considerable differences appeared in other subjective and objective PA intensities (e.g., sedentary time, light PA) and categories (e.g., work, domestic PA). Higher daily steps and longer time spent in MVPA correlated with lower whole-body adipose tissue percentage, leptin concentration, and less insulin resistance, regardless of familial influences. MVPA further linked with lower low-density lipoprotein (LDL) cholesterol, and light PA negatively associated with high-sensitivity C-reactive protein concentration, indicating lower low-grade inflammation. Study II uncovered in MZ and DZ BMI-discordant twins that the heavier co-twins displayed higher disinhibited eating, binge-eating scores, body dissatisfaction, ate less frequently according to their needs (most ate more than they needed), and exhibited less flexible control, independent of DNA and shared environment. Leaner and heavier co-twins agreed frequently that heavier co-twins have unhealthier eating behaviors in general, and especially eat more food and fatty food. Negligible differences arose for feelings of hunger, eating restraint, eating due to external or emotional triggers, or self-reported dietary intake. Overeating behaviors and lack of control over eating associated with larger subcutaneous fat – and binge eating with intra-abdominal fat – but the strongest positive linear link was between body dissatisfaction and subcutaneous fat, regardless of familial effects. Optimal regulation of food intake correlated with lower subcutaneous fat and better insulin sensitivity, and flexible control linked with lower intra-abdominal and liver fat and LDL cholesterol. Study III observed in MZ BMI-discordant twins that the heavier co-twins reported shorter sleep, greater tiredness, more frequent and severe snoring, and a chronotype closer to eveningness, regardless of genotype and early life environment. Trivial differences emerged for sleep quality, insomnia, and sleep schedule, and for objectively measured sleep duration, latency, efficiency, and fragmentation. The larger the self-reported sleep debt (sleep duration minus sleep need), the higher the disinhibited eating and binge-eating scores. More snoring correlated with larger subcutaneous, intra-abdominal, and liver fat, whole-body adipose tissue proportion, LDL, and triglycerides. In all three studies, none of the behaviors (besides flexible control) differed substantially within BMI-concordant twin pairs. In conclusion, lower PA, a lack of control over eating, and detrimental sleep characteristics were associated with a higher BMI, larger adipose tissue storage, and poorer metabolic health, regardless of age, sex, and familial influences. The uncovered behaviors might be keys for interventions to prevent weight gain, promote weight loss, and benefit metabolic health.
  • Stewart, Juhani (Helsingin yliopisto, 2022)
    In critical illness the risk of neurological insults is high, whether because of the illness itself, or as a treatment complication. As a result, the length of hospital stay and the risk of both further morbidity and mortality are all roughly doubled. One of the major challenges is the inability to monitor a sedated, mechanically ventilated patient’s neurological symptoms during intensive care treatment, due to a lack of reliable methods. The aims of this thesis research were to identify and test potential non-invasive methods, which would be predictive of neurological outcome, showing potential as neuromonitoring methods of critical care patients unable to self-report. As a guiding theme, all tested methods could be applied to actual critical care with relative ease. Patients were included from two groups with a notably high incidence of neurological complications, namely acute liver failure patients with hepatic encephalopathy (I), and aortic surgery patients operated during hypothermic circulatory arrest (II). The first group included 20 patients, and the latter 30 patients. Late mortality and quality of life was assessed for the aortic surgery patients (III), and the postoperative development of certain blood biomarkers (IV). The tested non-invasive neuromonitoring methods included electroencephalogram (EEG) variables from frontal or fronto-temporal abbreviated monitoring, frontal near-infrared spectroscopy, transcranial Doppler ultrasound measurements of the intracranial blood flow, and finally biomarkers. The last included established biomarkers with an association with neurological complications, namely neuron-specific enolase, and protein S100β, and several interesting biomarkers normally associated with tumours and pancreatitis. Of the tested methods, the frontal EEG variables showed greatest promise, but the addition of the temporal channels did not increase sensitivity. Spectral EEG variables were predictive of the stage of hepatic encephalopathy (I), while a novel EEG variable called wavelet subband entropy was predictive of neurological outcome (I). The hemispheric asymmetry of frontal EEG was reasonably predictive of neurological outcome after aortic surgery (II). None of the other tested methods were predictive of outcome (I, II, IV), except protein S100β, which was significantly higher in the poor outcome group 48 to 72 hours after hypothermic circulatory arrest (II). The quality of life of aortic surgery patients was good after 5 to 8 years, and comparable with the general population of chronically ill patients (III). The aim of this explorative research was to identify and test non-invasive neuromonitoring methods, suitable for use in critical care. Based on the results, frontal EEG variables are promising and predict the grade of hepatic encephalopathy and neurological outcome. The other tested methods were not predictive of neurological outcome. The long-term quality of life of aortic surgery patients is very good, despite the high risk for neurological complications.
  • Ruuska, Satu (Helsingin yliopisto, 2021)
    Background: Biliary atresia (BA) is a rare cholangiopathy of infancy. Without treatment, inflammation and obstruction of the biliary tracts leads to liver cirrhosis and death within the first 2 years of life. BA is treated with portoenterostomy (PE), in which an exit for bile from the liver is created by attaching a jejunal loop to the porta hepatis. If PE fails, the next treatment option is liver transplantation (LT). Since the development of LT programs in the late 1980s, the long-term outcome for BA has improved. Patients with BA may survive until adulthood with their native livers (NL). The aims: The long-term effects of BA on the general health of patients in childhood and adolescence are not well-known. The aims of this study were to assess three aspects of BA patients’ health: growth, bone health and the neurocognitive and motor developmental outcome. Methods: To investigate the early childhood growth of BA patients, the growth data as well as the dosage of post-surgical corticosteroid treatment were evaluated for a cohort of 28 BA patients diagnosed in Finland between 1987–2017 alive with their NL. To analyze bone health, a cohort of 49 patients diagnosed between 2000–2017 who had survived at least ≥ 1 year of age was evaluated. Medical records were reviewed for histories and diagnoses of rickets and fractures and for dual-energy X-ray absorptiometry (DXA) measurements. A prospective cross-sectional cohort of 39 patients aged 1–20 years followed up at the Helsinki University Children’s Hospital during 2019 were studied to determine their neurocognitive and motor developmental outcomes. Participants in this prospective study underwent age-appropriate neurocognitive and motor test assessments. Results: BA patients were born shorter than the national reference population with a median height of −0.6 (interquartile range [IQR] −1.3 to −0.1 standard deviation scores [SDS], p<0.001). The height gain of BA patients decelerated during the first 3 months and accelerated between 3 to 6 months of age. Between 2–6 years-of-age, height gain was stable. A high (>50 mg/kg of prednisolone) cumulative corticosteroid dosage caused a 0.18 (β −0.18, SE 0.04, p<0.001) SDS lower height per treatment week compared to low dosage. Fourteen percent of BA patients were diagnosed with rickets based on radiographic findings. The majority (75%) of fractures in BA patients occurred in infancy in patients with rickets. The number of fractures in children with BA in later childhood and in adolescence did not differ from normal population. DXA measurements showed normal bone mineral content (BMC) and areal bone mineral density (aBMD) between 5 to 10 years of age in NL and LT patients. The mean total intelligent quotient (IQ) of BA patients was 91 (SD ±15), lower than in the normal population (100±15, p<0.01). Out of 30 patients tested, 43.3% were either at risk or fulfilled criteria for motor impairment. Guardians reported elevated rates of functional problems affecting everyday life of BA patients in 5/8 domains assessed with a validated questionnaire. Conclusions: Post-PE corticosteroids have a measurable impact on height gain post-PE. This effect does not continue after 6 months of age. BA patients have a clearly heightened risk for metabolic bone disease in the form of rickets in infancy. BA patients with NL and LT have BMC and aBMD measurements within the normal range during later childhood. Total IQ and motor developmental outcome among BA patients are compromised and early structured evaluation to identify individuals in need of additional support could enhance everyday functionality.
  • Lassmann-Klee, Paul G. (Helsingin yliopisto, 2021)
    In Northern Europe, the prevalence of asthma differs between countries, but an objective clinical comparison of bronchial inflammation is missing. Therefore, we aimed to study the fractional exhaled nitric oxide FENO, a biomarker of airway inflammation, in population samples of the general populations of Sweden, Finland and Estonia. We further aimed to analyse methodological and physiological features of FENO acquisition, such as mouthwashes and dependency of expiratory flow. We performed clinical interviews (n = 2658), FENO (n = 1498) and skin prick tests (SPT) in a random population from Sweden (Stockholm and Örebro), Finland (Helsinki), and Estonia (Narva and Saaremaa), during 1997–2003. To analyse the methodology of FENO, we performed two pilot clinical studies. Firstly, we measured FENO with an expiratory flow rate of 50 mL/s in a small random sample (12 asthmatic or healthy) and acquired a baseline, then repeated measurements (for 20 min) after a mouthwash with tap water or carbonated water. Additionally, we obtained FENO from 30 volunteers for multiple expiratory flow rates of 50, 30, 100 and 300 mL/s, after different mouthwash settings. With this dataset, we analysed the influence of mouthwashes in multiple-flow FENO and developed a conversion model, with a further cross-validation in five populations: healthy adults, healthy children, and patients with chronic obstructive pulmonary disease (COPD), asthma and alveolitis. In the pilot studies, the tap water mouthwash reduced FENO for only 2 min. The mouthwash with carbonated water lowered FENO more notably, for 12 min. Compared to the tap water mouthwash, the carbonated water mouthwash reduced FENO at all expiratory flows — 50, 30, 100 and 300 mL/s. The carbonated water mouthwash also lowered the maximum airway NO flux (_JawNO), but not the alveolar NO concentration (CANO) or capacity of the airways for NO diffusion (DawNO). We developed a non-linear model to perform FENO estimations obtained at different flows. The cross-validation resulted in a low deviation between estimated ^FENO (from 100 mL/s to 50 mL/s) and measured FENO (at 50 mL/s) in children (0.27 ppb), the mixed adult population (0.28 ppb), and in healthy adults (0.44 ppb). The deviation was higher in patients with COPD (1.16 ppb), alveolitis (1.47 ppb), and asthma (1.68 ppb). We applied the non-linear model to standardise the FENO values at 50 mL/s in the epidemiological study. In the population study, the median (interquartile range) of FENO (ppb) was 15.5 (9.3) in Sweden, in Finland 15.4 (13.6), and in Estonia 12.5 (9.6). We found the lowest FENO in Estonian centres —Saaremaa 13.1 (9.5) and Narva 11.8 (8.6). Asthma was associated with FENO≥25 ppb, odds ratio (OR) 3.91 (95% confidence interval: 2.29–6.32) and adjusted for skin prick test (SPT), iv Paul G. Lassmann-Klee smoking, sex and study centre. Atopy increased the likelihood of asthma, OR 3.19 (2.02–5.11). Having asthma was more likely in Stockholm OR 5.54 (2.18–14.79), Örebro OR 3.38 (1.59– 8.09), Helsinki OR 2.40 (1.04–6.02), and Narva OR 2.45 (1.05–6.19), compared to Saaremaa. We conclude that a carbonated water mouthwash reduces oral NO contamination for 12 min, and is more pronounced than tap water, with multiple flows, without affecting CANO or DawNO. We established a model for converting FENO between multiple expiratory flows, with further tentative use of predicting extended flow parameters, _JawNO and CANO. We confirmed the higher prevalence of allergic airway inflammation and asthma in Sweden and Finland, compared to Estonia. An increased FENO and atopy were independently associated with a higher risk of asthma. Our epidemiological findings support the west–east disparity of allergic diseases.
  • Kornilov, Roman (Helsingin yliopisto, 2021)
    Defects in bone structures are extensive problems, faced by millions of people worldwide. Still, current methods do not always provide a satisfactory result in restoring functions after trauma or disease treatment. Bone tissue engineering methods require refinement; therefore, cell-derived agents could be used to enhance treatment outcomes. The extracellular vesicles (EVs) are potential new agents that could improve bone formation in tissue engineering. EVs are released from the cellular membrane and contain mRNA, miRNA and other tissue factors, affecting recipient cells. As EVs can initiate cell differentiation, it is important to understand the mechanisms behind their operation, since they have shown applicability as biomimetic tools for guided lineage-specific differentiation and cell-free therapies. In this thesis, a novel cost-effective and easily standardizable method for EV isolation was developed, based on ultrafiltration of cell culture media. The method may be used in a wide range of cell culture applications increasing reproducibility of EV research results between laboratories. As EVs are proposed to be central in intercellular communication, the potency of EVs from activated monocytes (MC) and osteoclasts was evaluated on adipose tissue mesenchymal stromal cells (MSCs). The EVs from activated MCs promoted secretion of cytokines, potentially representing an immunomodulatory mechanism, while also upregulating gene expression of matrix metalloproteinases in MSCs, affecting tissue remodeling. Further, to investigate the role of EVs in malignant bone conditions, MSCs and pre-osteoblasts were treated with EVs released from osteosarcoma cells (OS-EVs) and the epigenetic signature of OS-EVs was assessed. Overall, this study provided evidence that epigenetic regulation appears to be an early event in the transformation of MSCs during the development of OS. To develop new methods for tissue engineering, we conducted an in vivo study on minipigs. The minipig was selected as the large animal model of choice due to physiological and anatomical similarities of the jaws and teeth with humans. To reconstruct a large continuous defect in the mandible, a composite consisting of PTMC (poly[trimethylene carbonate]) and calcium phosphate ceramic was tested in a mechanically loaded area. The bioimplant scaffolds were manufactured individually based on CT imaging data from each minipig using computer-aided design and manufacturing (CAD-CAM). The mandibular defect was stabilized with custom-made 3D printed titanium reconstruction plates as the bioimplant itself was not load-bearing. The results of this thesis work investigated different strategies in bone remodeling, e.g., the effect and mechanisms of EVs on the immune system and bone remodeling as well as in malignant transformation. Further studies are necessary to confirm the proof-of-concept in bone remodeling to implement these strategies in patient treatments.
  • Huhdanpää, Hanna (Helsingin yliopisto, 2021)
    Surprisingly few studies have examined the association between sleep and executive functions (EFs) and psychiatric symptoms among preschool-aged children referred for child psychiatric evaluation. At the population level, it is not known whether sleep difficulties during infancy and early childhood are associated longitudinally with ADHD-related (i.e., inattentive and/or hyperactive) symptoms. Studies I and II of this project evaluated sleep and EFs among preschool-aged children referred to a child psychiatric outpatient clinic and among their typically developing peers. Studies I and III evaluated the association between sleep and EFs and the psychiatric symptoms of these patients. A longitudinal population-based study (Studies IV and V) investigated the associations between children’s early sleep difficulties (at the ages of 3, 8, 24 months and five years), several family risk factors, and subsequent inattentive/hyperactive symptoms at five years of age. The study project was based on two samples (clinical and epidemiological). The first sample consisted of clinical patient data (Study I, N = 139; Studies II–III, N = 171) collected from two Helsinki University Central Hospital child psychiatric outpatient clinics (Helsinki, Vantaa) during 03/2015–05/2017. Parents evaluated their child’s psychiatric symptoms using the Child Behavior Checklist (CBCL) and sleep difficulties using the Sleep Disturbance Scale for Children (SDSC). EFs were assessed using the Attention and Executive Function Rating Inventory for Preschoolers (ATTEX-P; validated among Finnish preschoolers), which was completed by a daycare teacher. The reference group in Study I comprised age- and gender-matched children from the previous epidemiological sample. In Studies II and III, the reference groups consisted of daycare children in Lahti. In Study I, approximately one third (33.1%) of the three- to seven-year-old children referred for child psychiatric evaluation had sleep difficulties, and 14.4% slept less than nine hours per day, which was significantly less than the control children (2.9%, p < 0.001). The referred children also had more restless sleep, nightmares, morning tiredness, daytime somnolence, and night awakenings than the control children (p < 0.05). In the multiple logistic regression models, parent-reported children’s sleep difficulties significantly increased the risk of the children’s overall psychiatric symptoms (OR = 5.3, 95% CI = 2.2–12.6, p < 0.001) and internalising (OR = 2.5, 95% CI = 1.1–5.5, p < 0.05) and externalising (OR = 3.7, 95% CI = 1.6–8.5, p < 0.01) symptoms. In Study II, the four- to seven-year-old children referred for child psychiatric evaluation had a significantly higher level of EF deficits than the reference children (i.e., higher ATTEX-P Total scores and all nine subscale scores, all p values < 0.001). More than half of the referred children (58.5%) had an ATTEX-P total score that was over the clinical cut-off. The patients were at a high risk (univariate OR = 12.4, p < 0.001; multivariate OR= 10.6, p < 0.001) of EF deficits (ATTEX-P total score over the clinical cut-off) compared to the reference children. In Study III, the referred children were assigned to symptom groups of mainly internalising, mainly externalising, combined or mild symptoms, measured by the CBCL. All the children in the symptom groups had marked EF deficits: a higher ATTEX-P total score (all p values < 0.001) and a higher score in eight of the nine ATTEX-P subscales (p values ranging between < 0.001 and 0.039) than the reference children. The children in the mainly internalising symptom group had less impulsivity than those in the other symptom groups, and less motor hyperactivity than those in the mainly externalising or both internalising and externalising symptom groups. The second sample comprised a population-based birth cohort (CHILD SLEEP, N = 1679) from the Pirkanmaa Hospital District (2011¬–2017). The parents completed several questionnaires during the mother’s pregnancy and when the child was 3, 8, 24 months, and five years old. Sleep duration, night awakenings and parent-reported sleep difficulties were measured using the Brief Infant Sleep Questionnaire (BISQ) and the Infant Sleep Questionnaire (ISQ). When the child was five years old, the parents rated their child's inattentive and/or hyperactive symptoms using two different questionnaires, the Five-to-Fifteen (FTF) and the Strengths and Difficulties (SDQ) questionnaires. In Study IV, children’s sleep duration reported by their parents at 3, 8, and 24 months of age was consistently associated with their inattentive symptoms at five years of age. Shorter sleep duration (less than 13.0 h per day) at as early as three months increased a child’s risk of later inattentive symptoms (OR 1.93, 95% CI = 1.24–3.01, p < 0.01). At 24 months of age, parent-reported sleep difficulties were related to inattentive and hyperactive symptoms at five years. At five years of age, night awakenings and parent-reported sleep difficulties were associated with concurrent inattentive and hyperactive symptoms. In Study V, children’s shorter sleep duration (less than 13.0 h per day at the age of three months), parents’ depressive symptoms during and after pregnancy, a more negative family atmosphere at three months, and a hostile/punitive parenting style at eight months were related to the risk of the children having inattentive and/or hyperactive symptoms at five years of age. Children with several risk factors (being a boy, maternal authoritarian parenting style, more negative family atmosphere, and persistent maternal depressive symptoms) were at the highest risk (OR 8.40, CI 95% 3.17–22.30, p < 0.001) of having inattentive/hyperactive symptoms at five years of age. The results of this study highlight the fact that sleep problems and EF deficits are associated with both internalising and externalising symptoms among four- to seven-year-old children referred for child psychiatric evaluation. Early screening and identification of sleep difficulties and EF deficits among preschool-aged children with psychiatric symptoms should guide treatment choices. Treating a child’s sleep problems may possibly alleviate the intensity of their psychiatric symptoms. On a populational level, early screening and treatment of a child’s sleep problems and parental support, including the treatment of parental depression, should be available already during infancy and the preschool period, especially for families with several risk factors for the child later developing ADHD-related symptoms. Identifying families with high-risk children (i.e., several risk factors already during infancy) and providing adequate and early support for these families is of great importance.
  • Tuomisto, Karolina (Helsingin yliopisto, 2021)
    Obesity, type 2 diabetes and cardiovascular disease are major causes of morbidity and mortality in the world. They are known to be linked by an unhealthy diet and low levels of physical activity. Furthermore, obesity is a risk factor for type 2 diabetes, and both increase a person’s cardiovascular risk. Subclinical inflammation has been associated with each of the conditions, but there have been limited attempts to establish whether it is another major link between them. To test our hypothesis subclinical inflammation being an important biological link between the obesity-type 2 diabetes-cardiovascular disease trifecta, we analysed whether subclinical inflammation precedes and predicts, obesity, type 2 diabetes, cardiovascular disease and all-cause death. Three large, population-based prospective Finnish cohorts and one North American cohort were used for the analyses of the present study, namely FINRISK 1992, FINRISK 2002, DILGOM 2007 and the FHS Offspring Study. The Finnish cohorts were further linked to nation-wide registers, providing information on deaths, disease diagnoses and drug purchases. We explored links of subclinical inflammation with obesity in both cross-sectional and longitudinal settings using the DILGOM 2007 cohort. Inflammation markers were associated with obesity measures at baseline, as well as with weight gain, increasing waist circumference, increasing body fat percentage, or increasing body-mass index (BMI) during a 7-year follow-up. However, after adjusting for baseline BMI, longitudinal associations were no longer significant for any of the outcomes. This suggests that subclinical inflammation does not precede obesity, and may be its consequence rather than the cause. With the help of advanced metabolomics, we identified 545 eicosanoids and related oxylipins in the FINRISK 2002, DILGOM 2007 and FHS Offspring Study cohorts. Using stepwise Cox regression analysis, we determined that a three-eicosanoid risk score was associated with incident type 2 diabetes in three independent cohorts. Our findings imply that lipid-derived mediators of inflammation may play a role in the prediction of incident type 2 diabetes. Using a case-cohort design based on the follow-up of the FINRISK 1992 cohort, we found inflammation markers to be independent predictors of cardiovascular disease and all-cause death, especially in men. IgG class antibodies to periodontal pathogens as well as endotoxin were also associated with incident cardiovascular events, although endotoxin’s association was not independent of cholesterol levels. Further epidemiological studies and randomised clinical trials exploring links between inflammation markers and cardiovascular disease have confirmed the role of subclinical inflammation in the development of atherosclerosis. The findings of this thesis suggest that subclinical inflammation is associated with both metabolic and atherothrombotic aspects of common public health problems. It seems to be at least one of the links between obesity, type 2 diabetes, cardiovascular disease and death. The findings, together with current literature, suggest opportunities for early detection, estimation of disease risk and prevention as well as therapeutic targeting of subclinical inflammation to reduce the risk of cardiovascular disease. Once we understand better the biological processes underlying subclinical inflammation and the obesity-type 2 diabetes-cardiovascular disease trifecta, we may be able to develop safe and cost-effective therapies addressing metabolic and atherothrombotic characteristics of each of these diseases.
  • Syreeni, Anna (Helsingin yliopisto, 2021)
    Type 1 diabetes (T1D) is an autoimmune form of diabetes with a high incidence in Finland. The typical onset age of T1D is in childhood, but the disease may also manifest in adults. The late complications of diabetes in the kidneys (diabetic nephropathy) and in the eyes (diabetic retinopathy), however, appear only after living for years with diabetes. High blood glucose levels are a major risk factor for these microvascular complications. Glycated hemoglobin (HbA1c), a measure of long-term hyperglycemia, constantly forms when free glucose attaches to hemoglobin in the red blood cells. Earlier genetic and heritability analyses have shown that all these phenotypes, T1D, HbA1c, and complications of diabetes are affected by the genome. The studies included in this thesis had four specific aims: 1) to examine the relationship between leukocyte telomere length and diabetic nephropathy, 2) to study genetic variability in three histone methyltransferases and the risk of diabetes complications, 3) to find genetic factors associated with HbA1c in type 1 diabetes in a genome-wide association study, and 4) to look for genetic variants and genes associated with age at diagnosis of type 1 diabetes (Study IV). The Finnish Diabetic Nephropathy (FinnDiane) Study was the primary study cohort. Several other diabetes cohorts served as replication cohorts (Studies II and III) or were included together with the FinnDiane in a genome-wide association study meta-analysis as in Study IV. As commonly shown, telomere length shortened with age in our cohort. Most importantly, short telomere length and a higher proportion of short telomeres predicted diabetic nephropathy progression. In the candidate gene study, an exonic SNP in SUV39H2 was associated with diabetic retinopathy. Study III showed that HbA1c is partly an inherited trait in diabetes. A locus on chromosome 13 closest to the gene RXFP2 was associated with HbA1c with genome-wide significance. Additionally, many variants known to be associated with HbA1c in the general population had a similar direction in our diabetes cohort. In Study IV, our top associations for T1D diagnosis age were in known T1D risk loci in the HLA region on chromosome 6 and chromosome 17q12, a known risk locus for childhood-onset asthma as well. However, most of the suggestive associations were at genomic regions not previously implicated in T1D. A transcriptome-wide association study highlighted genes such as IKZF3, GSDMB, ORMDL3, and ZBPB2 in the chr17q12 locus. To conclude, the four studies included in this thesis utilized various genetic study approaches and found significant associations between genetic variants and age of diagnosis of T1D, HbA1c, and diabetes complications. More importantly, the HbA1c values are surprisingly stable over time and are affected by genetic variants. An analysis integrating the information from genetic variants and gene expression suggested genes that have potential age-related effects in the pathogenesis of T1D.

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