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  • Tuisku, Katinka (Helsingin yliopisto, 2002)
  • Pohja, Marjatta (Helsingin yliopisto, 2005)
  • Heinonen, Mira (Helsingin yliopisto, 2011)
    Breast cancer is the most common cancer among women. Although its prognosis has improved nowadays, methods to predict the progression of the disease or to treat it are not comprehensive. This thesis work was initiated to elucidate in breast carcinogenesis the role of HuR, a ubiquitously expressed mRNA-binding protein that regulates gene expression posttranscriptionally. HuR is predominantly nuclear, but it shuttles between the nucleus and the cytoplasm, and this nucleocytoplasmic translocation is important for its function as a RNA-stabilizing and translational regulator. HuR has been associated with diverse cellular processes, for example carcinogenesis. The specific aims of my thesis work were to study the prognostic value of HuR in breast cancer and to clarify the mechanisms by which HuR contributes to breast carcinogenesis. My ultimate goal is, by better understanding the role of HuR in breast carcinogenesis, to aid in the discovery of novel targets for cancer therapies. HuR expression and localization was studied in paraffin-embedded preinvasive (atypical ductal hyperplasia, ADH, and ductal carcinoma in situ, DCIS) specimens as well in sporadic and familial breast cancer specimens. Our results show that cytoplasmic HuR expression was already elevated in ADH and remained elevated in DCIS as well as in cancer specimens. Clinicopathological analysis showed that cytoplasmic HuR expression associated with the more aggressive form of the disease in DCIS, and in cancer specimens it proved an independent marker for poor prognosis. Importantly, cytoplasmic HuR expression was significantly associated with poor outcome in the subgroups of small (2 cm) and axillary lymph node-negative breast cancers. HuR proved to be the first mRNA stability protein the expression of which is associated in breast cancer with poor outcome. To explore the mechanisms of HuR in breast carcinogenesis, lentiviral constructs were developed to inhibit and to overexpress the HuR expression in a breast epithelial cell line (184B5Me). Our results suggest that HuR mediates breast carcinogenesis by participating in processes important in cell transformation, in programmed cell death, and in cell invasion. Global gene expression analysis shows that HuR regulates genes participating in diverse cellular processes, and affects several pathways important in cancer development. In addition, we identified two novel target transcripts (connective tissue growth factor, CTGF, and Ras oncogene family member 31, RAB31) for HuR. In conclusion, because cytoplasmic HuR expression in breast cancer can predict the outcome of the disease it could serve in clinics as a prognostic marker. HuR accumulates in the cytoplasm even at its non-invasive stage (ADH and DCIS) of the carcinogenic process and supports functions essential in cell alteration. These data suggest that HuR contributes to carcinogenesis of the breast epithelium.
  • Stenman, Jakob (Helsingin yliopisto, 2002)
  • Hölttä, Veera (Juvenes Print, 2012)
    T cells are CD4 lymphocytes participating in cell-mediated immunity, and play a critical role in immune-mediated diseases. T cells divide further into subclasses such as Th1, Th2, and Th17 that participate in mucosal immunity responses caused by extracellular pathogens and also play a role in autoimmune diseases. Th17 cells produce cytokines called the interleukin-17 family (IL-17). Regulatory CD4+ T cells marked by CD4, CD25, and forkhead box P3 (FOXP3), contribute to maintaining tolerance and regulating immune responses to antigens. This doctoral thesis studies the role of IL-17 type of immunity in intestinal inflammation in Crohn s disease, ulcerative colitis, celiac disease, and type I diabetes (T1D). In particular, the study explores the balance between effector and regulatory T cells in active and inactive Crohn s disease in adults, as well as in pediatric patients with Crohn s disease and ulcerative colitis. Furthermore, the investigation focuses on the effect of anti-TNF-α treatment on the effector and regulatory T cells in Crohn s disease in adults. Adult patients with Crohn s disease had higher numbers of intestinal IL-17+ and FOXP3+ cells than did control subjects, both before and after the anti-TNF-α treat-ment. Intestinal interferon-γ and IL-17 mRNA expression was higher in Crohn s disease and remained elevated after anti-TNF-α treatment, although the treatment improved intestinal balance between IL-17+ effector and regulatory T cells. In Crohn s disease, mRNA expression of IL-17A, IL-6, and FOXP3 was increased. Fecal IL-17 concentration showed increase in patients with active disease. IL-17 enhanced the IL-8 and TNF-α response of the epithelial cell line to lipopolysaccha-ride in vitro. The findings suggest that activation of the IL-17 axis is fundamentally connected to the etiology of Crohn s disease and may represent the basis for the relapsing nature of the disease. In pediatric patients, IL-17, IL-22, IL-6, and FOXP3+ mRNA up-regulation and increase in the number of IL-17+ and FOXP3+ cells existed in inflammatory bowel disease. Activation of the IL-17/IL-22 axis and up-regulation of FOXP3 occurred both in pediatric Crohn s disease and ulcerative colitis, indicating shared immuno-logical aberrancy. In pediatric patients with untreated celiac disease, the mucosal expression of IL-17 and FOXP3 transcripts were elevated as compared with TGA-negative reference children, children with potential celiac disease, gluten-free diet-treated children with celiac disease, or children with T1D. Enhanced spontaneous secretion of IL-1β, IL-6, and IL-17 occurred in biopsy specimens from patients with untreated celiac disease. Activation of anti-apoptotic bcl-2 in IL-17-treated CaCo-2 epithelial cells suggests that IL-17 might be involved in mucosal protection. Up-regulation of IL-17, howev-er, could serve as a biomarker for the development of villous atrophy and active celiac disease.
  • Karlberg, Susann (Helsingin yliopisto, 2012)
    Mulibrey nanism (MUL; OMIM 253250) is an autosomal recessive disorder belonging to the Finnish disease heritage and currently classified as a peroxisomal disorder. MUL is characterized by intrauterine-onset growth restriction, typical dysmorphic features, restrictive perimyocardial heart disease, and severe insulin resistance. The causative gene, TRIM37, is located on chromosome 17q22-q23 and encodes for a peroxisomal protein (TRIM37) with ubiquitin E3-ligase activity, suggesting its role in proteasomal protein degradation. All 19 mutations identified to date, including 4 in Finnish patients, are likely to produce a non-functioning protein. For many decades, the clinical care and follow-up of Finnish MUL patients were based at the Children s Hospital in Helsinki, generating a unique clinical experience and data set for this patient group. In follow-up, it became evident that a substantial proportion of these patients developed hypogonadism, were infertile, and had an increased risk of developing tumors. Thus, the principal focus of this study was to characterize the hypogonadism and infertility associated with this disorder, and furthermore to define the tumors and tumor predisposition in MUL, both clinically and immunohistochemically. A total of 92 Finnish patients (0.7-77 years) were included in the study; 22 post pubertal females participated in the female hypogonadism study, and 28 male patients participated in the male hypogonadism study. All hospital records were evaluated, and physical, laboratory, and radiological examinations were performed according to clinical protocols. Biopsies (taken on clinical grounds) and autopsy samples were used for histological and immunohistochemical studies. In addition, 15 freshly frozen samples from sporadic ovarian fibrothecomas were analyzed for the role of TRIM37 in the development of these tumors. All MUL patients developed hypogonadism due to a primary gonadal defect and were either infertile or severely subfertile. Women demonstrated spontaneous puberty, incomplete breast development, and early irregularity of menstrual periods with subsequent ovarian failure. Their ovaries were hypoplastic and their uteri were small. The men also experienced spontaneous puberty with somewhat small testes characterized by varying degrees of degeneration and few mature germ cells. Semen samples showed either severe oligoasthenozoospermia or azoospermia. No spontaneous pregnancies had been conceived among the MUL patients. Four men had undergone infertility treatment, which in one case was successful, resulting in the delivery of a healthy child. The MUL patients displayed a high frequency of both benign and malignant tumors especially of endocrine origin. A total of 232 tumorous lesions in several different organs were discovered in the patient cohort. Histologically, the architecture of several organs was disturbed, indicating aberrant organogenesis. One of the most frequent tumors was ovarian fibrothecomas, which are fairly uncommon in the general population, found in 55% of the female patients. The study of inherited monogenic disorders has contributed substantially to our understanding of gene function and human disease. In MUL, mutations in TRIM37 lead to failure of sexual maturation in both females and males, and fertility is seriously compromised. In addition, the patients are at a very high risk for developing benign and malignant tumors in several different organs. This study suggests a role for TRIM37 protein in the cellular functions governing gametogenesis, gonadal function, and proliferation.
  • Karlberg, Niklas (Helsingin yliopisto, 2009)
    Background: Mulibrey nanism (MUL; Muscle-liver-brain-eye nanism; OMIM 253250) is an autosomal recessive growth disorder more prevalent in Finland than elsewhere in the world. Clinical characteristics include severe prenatal onset growth restriction, cardiopathy, multiple organ manifestations but no major neurological handicap. MUL is caused by mutations in the TRIM37 gene on chromosome 17q22-23, encoding a peroxisomal protein TRIM37 with ubiquitin E3-ligase activity. Nineteen different mutations have been detected, four of them present in the Finnish patients. Objective: This study aimed to characterize clinical and histopathological features of MUL in the national cohort of Finnish patients. Patients and methods: A total of 92 Finnish patients (age 0.7 to 77 years) participated in the clinical follow-up study. Patients hospital records and growth charts were reviewed. Physical, radiographic and laboratory examinations were performed according to a clinical protocol. Thirty patients (18 females) were treated with recombinant human GH for a median period of 5.7 years. Biopsies and autopsy samples were used for the histopathological and immunohistochemical analyses. Results: MUL patients were born small for gestational age (SGA) with immature craniofacial features after prenatal-onset growth restriction. They experienced a continuous deceleration in both height SDS and weight-for-height (WFH) postnatally. In infancy feeding difficulties and frequent pneumonias were common problems. At the time of diagnosis (median age 2.1 years) characteristic craniofacial, radiological and ocular features were the most constant findings. MUL patients showed a dramatic change in glucose metabolism with increasing age. While the children had low fasting glucose and insulin levels, 90% of the adults were insulin resistant, half had type 2 diabetes and an additional 42% showed impaired glucose tolerance (IGT). Seventy percent fulfilled the National Cholesterol Education Program (NCEP) Adult Treatment Panel III criteria for metabolic syndrome as adults. GH therapy improved pre-pubertal growth but had only minor impact on adult height (+5 cm). Interestingly, treated subjects were slimmer and had less frequent metabolic concerns as young adults. MUL patients displayed histologically a disturbed architecture with ectopic tissues and a high frequency of both benign and malignant tumours present in several internal organs. A total of 232 tumorous lesions were detected in our patient cohort. The majority of the tumours showed strong expression of endothelial cell marker CD34 as well as α-smooth muscle actin (α-SMA). Fifteen of the tumours were malignant and seven of them (five Wilms tumours) occurred in the kidney. Conclusions: MUL patients present a distinct postnatal growth pattern. Short-term response of GH treatment is substantial but the long-term impact remains modest. Although MUL patients form a distinct clinical and diagnostic entity, their clinical findings vary considerably from infancy to adulthood. While failure to thrive dominates early life, MUL adults develop metabolic syndrome and have a tendency for malignancies and vascular lesions in several organs. This speaks for a central role of TRIM37 in regulation of key cellular functions, such as proliferation, migration, angiogenesis and insulin signalling.
  • Haapamäki, Ville (Helsingin yliopisto, 2004)
  • Bensch, Frank (Helsingin yliopisto, 2012)
    Serious injuries of the spine and pelvis are common in level I trauma centers, and are usually the result of high-energy accidents such as motor vehicle accidents (MVA) or falls from a height, but increasingly also sports and recreational accidents. Even presumably minor accidents can result in serious injury depending on the injury mechanism. The risk of acquiring a fracture is also tied to possible predisposing factors such as a weakened bone structure in osteoporosis, or an increased stiffness of the spine in ankylosing spondylitis. ----- Spinal injuries have a potential for catastrophic, life-altering consequences, because they are associated with spinal cord injury (SCI). A missed or inappropriately managed spinal injury can result in secondary SCI or progression of the initial damage. But also pelvic fractures pose a serious threat, as there are large-caliber blood vessels, nerves, and the lower urinary tract in close proximity to the pelvic bones. An acute bleeding into the pelvic area can remain clinically silent for an extended amount of time due to circulatory compensation processes. Exclusion of these occult injuries by imaging techniques is therefore imperative in order to detect a serious injury as early as possible and administer appropriate treatment. Time-, space-, and cost restraints as well as the patient s stability limit the application of imaging modalities in the golden hour of trauma resuscitation, which is arguably the most critical phase for the patient s outcome. The optimal choice of imaging methods is therefore crucial. But also the knowledge of injury patterns and demographic risk factors contributes to the correct diagnosis of a serious injury. This thesis focuses on injury patterns of the spine in conjunction with high-energy accidents, as well as demographic patterns and the optimal choice of imaging modality. It consists of five publications with a total of 2375 patients, covering a time frame from January 2001 to September 2009. There is special emphasis on vertebral burst fracture, which is the most common fracture in the thoracolumbar area, and which has furthermore a high potential for SCI due to its unstable nature. Also the bony pelvis as an extension of the spine receives special reference. According to our results, serious spinal injury as a result of blunt trauma occurs in all age groups and independently of gender, and even minor trauma energies can result in serious trauma. Trauma energy does have an influence though, as the incidence of spine fractures increases with increasing falling height, and burst fractures and spine fractures on multiple levels become more frequent. But also other blunt trauma mechanisms had multiple spine fractures in up to 32 % of cases, whereof 29 % were non-contiguous. Burst fracture was seen on multiple levels in 10 % of cases, with 50 % being non-contiguous. The frequent occurrence of vertebral fractures and especially burst fractures on non-contiguous levels makes imaging of the whole spine necessary in conjunction with high-energy accidents, especially in obtunded patients. Radiography demonstrates unstable vertebral fractures with acceptable accuracy, particularly in the lumbar spine (LS). Summation of overlapping tissue in these areas makes the identification of the hall marks of an unstable facture difficult, which can lead to an injury being missed, or wrongly classified as stable. Neurological deficit was most frequent and serious in the CS. In the pelvic area, radiography detected only 55 % of fractures diagnosed by multidetector computed tomography (MDCT), and in 11 % findings were false negatively normal. Additionally, Tile classification of fractures was correct in 59 % of injuries, whereas the subtype was correct in only 14 %. The pelvis was false negatively classified as stable in 40 % of cases. Sport and recreational accidents had an overall incidence of injury of one in five, of which 71 % were considered to be serious. The three most common types of serious injury were intracranial injury, fractures of facial bones, and vertebral injuries. The most common accident mechanisms were bicycling, horseback riding, and team ball sports, with bicycling causing most frequently serious injury. In conclusion, it is recommended using MDCT to rule out serious injury of the spine and pelvis in adult victims of high-energy accidents of all age groups and both genders, especially in regard to multilevel injuries and injuries of the cervical spine. Even in presumably minor trauma, a high level of suspicion is required, and MDCT should be employed if the clinical finding is uncertain. MDCT is fast, cost-effective, and demonstrates injuries of the spine and pelvis unambiguously, benefiting the trauma patient s outcome.
  • Laaksonen, Elina (Helsingin yliopisto, 2010)
    Socioeconomic health inequalities have been widely documented, with a lower social position being associated with poorer physical and general health and higher mortality. For mental health the results have been more varied. However, the mechanisms by which the various dimensions of socioeconomic circumstances are associated with different domains of health are not yet fully understood. This is related to a lack of studies tackling the interrelations and pathways between multiple dimensions of socioeconomic circumstances and domains of health. In particular, evidence from comparative studies of populations from different national contexts that consider the complexity of the causes of socioeconomic health inequalities is needed. The aim of this study was to examine the associations of multiple socioeconomic circumstances with physical and mental health, more specifically physical functioning and common mental disorders. This was done in a comparative setting of two cohorts of white-collar public sector employees, one from Finland and one from Britain. The study also sought to find explanations for the observed associations between economic difficulties and health by analysing the contribution of health behaviours, living arrangements and work-family conflicts. The survey data were derived from the Finnish Helsinki Health Study baseline surveys in 2000-2002 among the City of Helsinki employees aged 40-60 years, and from the fifth phase of the London-based Whitehall II study (1997-9) which is a prospective study of civil servants aged 35-55 years at the time of recruitment. The data collection in the two countries was harmonised to safeguard maximal comparability. Physical functioning was measured with the Short Form (SF-36) physical component summary and common mental disorders with the General Health Questionnaire (GHQ-12). Socioeconomic circumstances were parental education, childhood economic difficulties, own education, occupational class, household income, housing tenure, and current economic difficulties. Further explanatory factors were health behaviours, living arrangements and work-family conflicts. The main statistical method used was logistic regression analysis. Analyses were conducted separately for the two sexes and two cohorts. Childhood and current economic difficulties were associated with poorer physical functioning and common mental disorders generally in both cohorts and sexes. Conventional dimensions of socioeconomic circumstances i.e. education, occupational class and income were associated with physical functioning and mediated each other’s effects, but in different ways in the two cohorts: education was more important in Helsinki and occupational class in London. The associations of economic difficulties with health were partly explained by work-family conflicts and other socioeconomic circumstances in both cohorts and sexes. In conclusion, this study on two country-specific cohorts confirms that different dimensions of socioeconomic circumstances are related but not interchangeable. They are also somewhat differently associated with physical and mental domains of health. In addition to conventionally measured dimensions of past and present socioeconomic circumstances, economic difficulties should be taken into account in studies and attempts to reduce health inequalities. Further explanatory factors, particularly conflicts between work and family, should also be considered when aiming to reduce inequalities and maintain the health of employees.
  • Koskela-Niska, Virpi (Helsingin yliopisto, 2015)
    Both ovarian and tubal cancers are rare. Therefore only a few studies explored such postmenopausal hormone therapies (HT) as used in Finland, as a risk factor for these cancers. I compared the incidence of ovarian and tubal cancer in HT users with the incidences of these cancers in the background population in two nationwide cohort studies. To exclude a number of potential confounders I conducted two case-control studies to further elucidate HT use as a risk factor for these cancers. The cohort studies included all women aged 50 or older who had used HT-regimens for 6 months or longer in 1994-2008. These women were identified from the Finnish Medical Reimbursement Register. The ovarian cancer cohort study included 224,015 women using estradiol-progestin therapy (EPT), whereas in the primary fallopian tube carcinoma (PFTC) cohort study included altogether 365,601 women using EPT (n=247,781) or estradiol-only therapy (ET)(n=117,820). These women were followed from the first HT purchase to the diagnosis of ovarian or tubal cancer, death, emigration or to the end of the study period through the national Finnish Cancer Registry. Relative risks of these cancers in HT users were estimated by comparing the incidence of ovarian or tubal cancer in HT users to the age-matched comparable background population and calculating standardized incidence ratios (SIR) and their 95% confidence intervals (CI). In the case-control studies, all 50-year-old or older women with incident ovarian cancer (n=3,958) or PFTC (n= 360) during 1995-2007 were identified from the Cancer Registry. The Population Register provided control women, 3 per each case of ovarian cancer and 10 per each case of PFTC, and parity data. The controls had to be alive and without ovarian/primary fallopian tube cancer and they were matched for age (+/- one month) and place or residence. The controls with an oophorectomy (n=506) or a salpingectomy (n=158) were excluded leaving 11,325 and 3,442 controls, respectively. Odds ratios (OR) with 95% CIs for various HT regimens were estimated by using conditional logistic regression adjusted for parity, ages at deliveries, hysterectomy and sterilization. The use of any type of EPT for less than five years did not modify the overall risk of ovarian cancer. Instead, the use of sequential EPT for five years or longer was associated with an elevation in the overall risk of ovarian cancer (SIR 1.21, 95% CI 1.06-1.37). The risk rises were most marked for serous (1.56; 1.33-1.80) and mixed cancer (1.54; 1.22-1.91) whereas the risk for mucinous cancer was decreased (0.47; 0.22-0.86). The risk increase connected to EPT use did not depend on the progestin type, mode or route of administration of EPT. The use of ET for five years or longer was linked with an increase in the risk for serous ovarian cancer (OR 1.45, 95% CI 1.20-1.75) while the risk of mucinous cancer was decreased (0.35; 0.19-0.67). As a whole the use of ET was accompanied with borderline rise in overall ovarian cancer risk (1.15; 0.99-1.32). In the users of sequential EPT, the risk rise was similar for endometroid (1.88; 1.24-2.86) and serous (1.32; 1.01-1.71) cancers. The use of continuous EPT, tibolone or E+LNG-IUS did not modify the risk of ovarian cancer. The use of ET was not a risk factor for PFTC. However, the use of sequential EPT for five years or longer was accompanied with a risk elevation (SIR 2.15, 95% CI 1.66-2.72), which was further increased if the use of sequential EPT continued for 10 years or longer (3.36; 2.02-5.24). In contrast, the use of continuous EPT did not modify the risk for PFTC. The uses of E+LNG-IUS for five years or longer was associated with increased risks of PFTC (ORs 2.84, 95% CI 1.10-7.38 and 3.37; 2.23-5.08, respectively), but this finding was based on low number of cases and controls. Postmenopausal hormone therapy use modifies the risks of both ovarian and fallopian tube cancers. The risk of serous and endometroid ovarian cancer rises but the risk of mucinous cancer decreases. The use of sequential EPT regimen is characterized with the highest risk elevations. In absolute terms, in 10,000 women using sequential EPT for five years or longer, there would be four extra cases of ovarian cancer and two extra cases of PFTC after follow-up of five years. These data should be incorporated into modern guidelines for the optimal use of HT.
  • Haukka, Eija (Helsingin yliopisto, 2010)
    This study examined the efficacy of a participatory ergonomics intervention in preventing musculoskeletal disorders (MSDs) and changing unsatisfactory psychosocial working conditions among municipal kitchen workers. The occurrence of multiple-site musculoskeletal pain (MSP) and associations between MSP and psychosocial factors at work over time were studied secondarily. A cluster randomized controlled trial was conducted during 2002-2005 in 119 municipal kitchens with 504 workers. The kitchens were randomized to an intervention (n = 59) and control (n = 60) group. The intervention lasted 11 to 14 months. The workers identified strenuous work tasks and sought solutions for decreasing physical and mental workload. The main outcomes were the occurrence of and trouble caused by musculoskeletal pain in seven anatomical sites, local musculoskeletal fatigue after work, and musculoskeletal sick leaves. Psychosocial factors at work (job control, skill discretion, co-worker relationships, supervisor support, mental strenuousness of work, hurry, job satisfaction) and mental stress were studied as intermediate outcomes of the intervention. Questionnaire data were collected at three months intervals during the intervention and the one-year post-intervention follow-up. Response rates varied between 92 % and 99 %. In total, 402 ergonomic changes were implemented. In the control group, 80 changes were spontaneously implemented within normal activity. The intervention did not reduce perceived physical workload and no systematic differences in any health outcomes were found between the intervention and control groups during the intervention or during the one-year follow-up. The results suggest that the intervention as studied in the present trial was not more effective in reducing perceived physical workload or preventing MSDs compared with no such intervention. Little previous evidence of the effectiveness of ergonomics interventions in preventing MSDs exists. The effects on psychosocial factors at work were adverse, especially in the two of the participating cities where re-organization of foodservices timed simultaneously with the intervention. If organizational reforms at workplace are expected to occur, the execution of other workplace interventions at the same time should be avoided. The co-occurrence of musculoskeletal pain at several sites is observed to be more common than pain at single anatomical sites. However, the risk factors of MSP are largely unknown. This study showed that at baseline, 73 % of the women reported pain in at least two, 36 % in four or more, and 10 % in six to seven sites. The seven pain symptoms occurred in over 80 different combinations. When co-occurrence of pain was studied in three larger anatomical areas (neck/low back, upper limbs, lower limbs), concurrent pain in all three areas was the most common combination (36 %). The 3-month prevalence of MSP (≥ 3 of seven sites) varied between 50 % and 61 % during the two-year follow-up period. Psychosocial factors at work and mental stress were strong predictors for MSP over time and, vice versa, MSP predicted psychosocial factors at work and mental stress. The reciprocality of the relationships implies either two mutually dependent processes in time, or some shared common underlying factor(s).
  • Sankelo, Marja (Helsingin yliopisto, 2009)
    Primary pulmonary hypertension (PPH), or according to the recent classification idiopathic pulmonary hypertension (IPAH), is a rare, progressive disease of pulmonary vasculature leading to pulmonary hypertension and right heart failure. Most of the patients are sporadic but in about 6% of cases the disease is familial (FPPH). In 2000 two different groups identified the gene predisposing to PPH. This gene, Bone morphogenetic protein receptor type 2 (BMPR2), encodes a subunit of transforming growth factor β (TGF-β) receptor complex. There is a genetic connection between PPH and hereditary hemorrhagic telangiectasia (HHT), a bleeding disorder characterized by local telangiectasias and sometimes with pulmonary hypertension. In HHT, mutations in ALK1 (activin like kinase type 1) and Endoglin, another members of the TGF-β signaling pathway are found. In this study we identified all of the Finnish PPH patients for the years 1986-1999 using the hospital discharge registries of Finnish university hospitals. During this period we found a total of 59 confirmed PPH patients: 55 sporadic and 4 familial representing 3 different families. In 1999 the prevalence of PPH was 5.8 per million and the annual incidence varied between 0.2-1.3 per million. Among 28 PPH patients studied, heterozygous BMPR2 mutations were found in 12% (3/26) of sporadic patients and in 33% of the PPH families (1/3). All the mutations found were different. Large deletions of BMPR2 were excluded by single-stranded chain polymomorphism analysis. As a candidate gene approach we also studied ALK1, Endoglin, Bone Morphogenetic Receptor Type IA (BMPR1A or ALK3), Mothers Against Decapentaplegic Homolog 4 (SMAD4) and Serotonine Transporter Gene (SLC6A4) using single-strand conformational polymorphism (SSCP) analysis and direct sequencing. Among patients and family members studied, we found two mutations in ALK1 in two unrelated samples. We also identified all the HHT patients treated at the Department of Otorhinolaryngology at Helsinki University Central Hospital between the years of 1990-2005 and 8 of the patients were studied for Endoglin and ALK1 mutations using direct sequencing. A total of seven mutations were found and all the mutations were different. The absence of a founder mutation in the Finnish population in both PPH and HHT was somewhat surprising. This suggests that the mutations of BMPR2, ALK1 and Endoglin are quite young and the older mutations have been lost due to repetitive genetic bottlenecks and/or negative selection. Also, other genes than BMPR2 may be involved in the pathogenesis of PPH. No founder mutations were found in PPH or HHT and thus no simple genetic test is available for diagnostics.
  • Luoma, Petri (Helsingin yliopisto, 2007)
    Thesis focuses on mutations of POLG1 gene encoding catalytic subunit polγ-α of mitochondrial DNA polymerase gamma holoenzyme (polG) and the association of mutations with different clinical phenotypes. In addition, particular defective mutant variants of the protein were characterized biochemically in vitro. PolG-holoenzyme is the sole DNA polymerase found in mitochondria. It is involved in replication and repair of the mitochondrial genome, mtDNA. Holoenzyme also includes the accessory subunit polγ-β, which is required for the enhanced processivity of polγ-α. Defective polγ-α causes accumulation of secondary mutations on mtDNA, which leads to a defective oxidative phosphorylation system. The clinical consequences of such mutations are variable, affecting nervous system, skeletal muscles, liver and other post-mitotic tissues. The aims of the studies included: 1) Determination of the role of POLG1 mutations in neurological syndromes with features of mitochondrial dysfunction and an unknown molecular cause. 2) Development and set up of diagnostic tests for routine clinical purposes. 3) Biochemical characterization of the functional consequences of the identified polγ-α variants. Studies describe new neurological phenotypes in addition to PEO caused by POLG1 mutations, including parkinsonism, premature amenorrhea, ataxia and Parkinson s disease (PD). POLG1 mutations and polymorphisms are both common and/or potential genetic risk factors at least among the Finnish population. The major findings and applications reported here are: 1) POLG1 mutations cause parkinsonism and premature menopause in PEO families in either a recessive or a dominant manner. 2) A common recessive POLG1 mutations (A467T and W748S) in the homozygous state causes severe adult or juvenile-onset ataxia without muscular symptoms or histological or mtDNA abnormalities in muscles. 3) A common recessive pathogenic change A467T can also cause a mild dominant disease in heterozygote carriers. 4) The A467T variant shows reduced polymerase activity due to defective template binding. 5) Rare polyglutamine tract length variants of POLG1 are significantly enriched in Finnish idiopathic Parkinson s disease patients. 6) Dominant mutations are clearly restricted to the highly conserved polymerase domain motifs, whereas recessive ones are more evenly distributed along the protein. The present results highlight and confirm the new role of mitochondria in parkinsonism/Parkinson s disease and describe a new mitochondrial ataxia. Based on these results, a POLG1 diagnostic routine has been set up in Helsinki University Central Hospital (HUSLAB).
  • Siltanen, Antti (Helsingin yliopisto, 2011)
    Heart failure is a common, severe, and progressive condition associated with high mortality and morbidity. Because of population-aging in the coming decades, heart failure is estimated to reach epidemic proportions. Current medical and surgical treatments have reduced mortality, but the prognosis for patients has remained poor. Transplantation of skeletal myoblasts has raised hope of regenerating the failing heart and compensating for lost cardiac contractile tissue. In the present work, we studied epicardial transplantation of tissue-engineered myoblast sheets for treatment of heart failure. We employed a rat model of myocardial infarction-induced acute and chronic heart failure by left anterior descending coronary artery ligation. We then transplanted myoblast sheets genetically modified to resist cell death after transplantation by expressing antiapoptotic gene bcl2. In addition, we evaluated the regenerative capacity of myoblast sheets expressing the cardioprotective cytokine hepatocyte growth factor in a rat chronic heart failure model. Furthermore, we utilized in vitro cardiomyocyte and endothelial cell culture models as well as microarray gene expression analysis to elucidate molecular mechanisms mediating the therapeutic effects of myoblast sheet transplantation. Our results demonstrate that Bcl2-expression prolonged myoblast sheet survival in rat hearts after transplantation and induced secretion of cardioprotective, proangiogenic cytokines. After acute myocardial infarction, these sheets attenuated left ventricular dysfunction and myocardial damage, and they induced therapeutic angiogenesis. In the chronic heart failure model, inhibition of graft apoptosis by Bcl-2 improved cardiac function, supported survival of cardiomyocytes in the infarcted area, and induced angiogenesis in a vascular endothelial growth factor receptor 1- and 2-dependent mechanism. Hepatocyte growth factor-secreting myoblast sheets further enhanced the angiogenic efficacy of myoblast sheet therapy. Moreover, myoblast-secreted paracrine factors protected cardiomyocytes against oxidative stress in an epidermal growth factor receptor- and c-Met dependent manner. This protection was associated with induction of antioxidative genes and activation of the unfolded protein response. Our results provide evidence that inhibiting myoblast sheet apoptosis can enhance the sheets efficacy for treating heart failure after acute and chronic myocardial infarction. Furthermore, we show that myoblast sheets can serve as vehicles for delivery of growth factors, and induce therapeutic angiogenesis in the chronically ischemic heart. Finally, myoblasts induce, in a paracine manner, a cardiomyocyte-protective response against oxidative stress. Our study elucidates novel mechanisms of myoblast transplantation therapy, and suggests effective means to improve this therapy for the benefit of the heart failure patient.
  • Pätilä, Tommi (Yliopistopaino, 2009)
    Heart failure is a common and highly challenging medical disorder. The progressive increase of elderly population is expected to further reflect in heart failure incidence. Recent progress in cell transplantation therapy has provided a conceptual alternative for treatment of heart failure. Despite improved medical treatment and operative possibilities, end-stage coronary artery disease present a great medical challenge. It has been estimated that therapeutic angiogenesis would be the next major advance in the treatment of ischaemic heart disease. Gene transfer to augment neovascularization could be beneficial for such patients. We employed a porcine model to evaluate the angiogenic effect of vascular endothelial growth factor (VEGF)-C gene transfer. Ameroid-generated myocardial ischemia was produced and adenovirus encoding (ad)VEGF-C or β-galactosidase (LacZ) gene therapy was given intramyocardially during progressive coronary stenosis. Angiography, positron emission tomography (PET), single photon emission computed tomography (SPECT) and histology evidenced beneficial affects of the adVEGF-C gene transfer compared to adLacZ. The myocardial deterioration during progressive coronary stenosis seen in the control group was restrained in the treatment group. We observed an uneven occlusion rate of the coronary vessels with Ameroid constrictor. We developed a simple methodological improvement of Ameroid model by ligating of the Ameroid–stenosed coronary vessel. Improvement of the model was seen by a more reliable occlusion rate of the vessel concerned and a formation of a rather constant myocardial infarction. We assessed the spontaneous healing of the left ventricle (LV) in this new model by SPECT, PET, MRI, and angiography. Significant spontaneous improvement of myocardial perfusion and function was seen as well as diminishment of scar volume. Histologically more microvessels were seen in the border area of the lesion. Double staining of the myocytes in mitosis indicated more cardiomyocyte regeneration at the remote area of the lesion. The potential of autologous myoblast transplantation after ischaemia and infarction of porcine heart was evaluated. After ligation of stenosed coronary artery, autologous myoblast transplantation or control medium was directly injected into the myocardium at the lesion area. Assessed by MRI, improvement of diastolic function was seen in the myoblast-transplanted animals, but not in the control animals. Systolic function remained unchanged in both groups.
  • Naukkarinen, Anna (Helsingin yliopisto, 2011)
    Myotonic dystrophies type 1 (DM1) and type 2 (DM2) are the most common forms of muscular dystrophy affecting adults. They are autosomal dominant diseases caused by microsatellite tri- or tetranucleotide repeat expansion mutations in transcribed but not translated gene regions. The mutant RNA accumulates in nuclei disturbing the expression of several genes. The more recently identified DM2 disease is less well known, yet more than 300 patients have been confirmed in Finland thus far, and the true number is believed to be much higher. DM1 and DM2 share some features in general clinical presentation and molecular pathology, yet they show distinctive differences, including disease severity and differential muscle and fiber type involvement. However, the molecular differences underlying DM1 and DM2 muscle pathology are not well understood. Although the primary tissue affected is muscle, both DMs show a multisystemic phenotype due to wide expression of the mutation-carrying genes. DM2 is particularly intriguing, as it shows an incredibly wide spectrum of clinical manifestations. For this reason, it constitutes a real diagnostic challenge. The core symptoms in DM2 include proximal muscle weakness, muscle pain, myotonia, cataracts, cardiac conduction defects and endocrinological disturbations; however, none of these is mandatory for the disease. Myalgic pains may be the most disabling symptom for decades, sometimes leading to incapacity for work. In addition, DM2 may cause major socio-economical consequences for the patient, if not diagnosed, due to misunderstanding and false stigmatization. In this thesis work, we have (I) improved DM2 differential diagnostics based on muscle biopsy, and (II) described abnormalities in mRNA and protein expression in DM1 and DM2 patient skeletal muscles, showing partial differences between the two diseases, which may contribute to muscle pathology in these diseases. This is the first description of histopathological differences between DM1 and DM2, which can be used in differential diagnostics. Two novel high-resolution applications of in situ -hybridization have been described, which can be used for direct visualization of the DM2 mutation in muscle biopsy sections, or mutation size determination on extended DNA-fibers. By measuring protein and mRNA expression in the samples, differential changes in expression patterns affecting contractile proteins, other structural proteins and calcium handling proteins in DM2 compared to DM1 were found. The dysregulation at mRNA level was caused by altered transciption and abnormal splicing. The findings reported here indicate that the extent of aberrant splicing is higher in DM2 compared to DM1. In addition, the described abnormalities to some extent correlate to the differences in fiber type involvement in the two disorders.