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  • Perttunen, Kristiina (Helsingin yliopisto, 2003)
  • Saastamoinen, Peppiina (Helsingin yliopisto, 2010)
    The overall objective of this study was to gain epidemiological knowledge about pain among employee populations. More specifically, the aims were to assess the prevalence of pain, to identify socio-economic risk groups and work-related psychosocial risk factors, and to assess the consequences in terms of health-related functioning and sickness absence. The study was carried out among the municipal employees of the City of Helsinki. Data comprised questionnaire survey conducted in years 2000-2002 and register data on sickness absence. Altogether 8960 40-60 year old employees participated to the survey (response rate 67%). Pain is common among ageing employees. Approximately 29 per cent of employees reported chronic pain and 15 per cent acute pain, and about seven per cent reported moderately or severely limiting disabling chronic pain. Pain was more common among those with lower level of education or in a low occupational class. -- Psychosocial work environment was associated with pain reports. Job strain, bullying at workplace, and problems in combining work and home duties were associated with pain among women. Among men combining work and home duties was not associated with pain, whereas organizational injustice showed associations. Pain affects functional capacity and predicts sickness absence. Those with pain reported lower level of both mental and physical functioning than those with no pain, physical functioning being more strongly affected than mental. Bodily location of pain or whether pain was acute or chronic had only minor impact on the variation in functioning, whereas the simple count of painful locations was associated with widest variation. Pain accounted for eight per cent of short term (1-3 day) sickness absence spells among men and 13 per cent among women. Of absence spells lasting between four and 14 days pain accounted for 23 per cent among women and 25 per cent among men, corresponding figures for over 14 day absence spells being 37 and 30 per cent. The association between pain and sickness absence was relatively independent of physical and psychosocial work factors, especially among women. The results of this study provide a picture of the epidemiology of pain among employees. Pain is a significant problem that seriously affects work ability. Information on risk groups can be utilized to make prevention measures more effective among those at high risk, and to decrease pain rates and thereby narrow the differences between socio-economic groups. Furthermore, the work-related psychosocial risk factors identified in this study are potentially modifiable, and it should be possible to target interventions on decreasing pain rates among employees.
  • Kuivalainen, Anna-Maria (Helsingin yliopisto, 2015)
    Background: Bone marrow aspiration and/or biopsy (BMAB) is a procedure used to diagnose and follow up various haematological diseases. It is usually performed at either the sternum or the iliac crest. The procedure often causes pain despite local infiltration anaesthesia. The objective of this study was to evaluate different means of pain relief during BMAB in adult patients. Special attention was paid to pre-procedural anxiety and its effect on pain. The commonly used local anaesthetic lidocaine was compared with articaine, an anaesthetic known for its ability to penetrate bone tissue. The effect of warming and buffering the lidocaine solution, measures expected to improve the anaesthetic action, was examined. Also investigated were sublingual fentanyl and inhaled 50% nitrous oxide (N2O) in oxygen (O2) as means of analgesia and sedation during BMAB. Patients: The patient population comprised 646 adult outpatients from the Department of Haematology, Helsinki University Central Hospital, Finland. Patients were randomized to treatment groups in trials comparing one intervention with another or with placebo. The studies were all patient-blinded. One study was observational and investigated the association between pain and pre-procedural anxiety. Patient recruitment was performed between 2007 and 2014. Main results: Pre-procedural anxiety intensified pain during BMAB in all trials. Median NRS (Numeral Rating Scale, 0 = no pain, 10 = worst pain imaginable) during infiltration was 3.0 (range 0 10, interquartile range (IQR) 3.0), puncture 2.0 (range 0 10, IQR 3.0), aspiration 4.0 (range 0 10, IQR 4.0), biopsy 4.0 (range 0 10, IQR 4.0) and immediately after BMAB 0 (range 0 9.0, IQR 1.0). Scores of 8 10 comprised 8.1%, 4.7%, 13.9%, and 12.4% of the scores for infiltration, puncture, aspiration and biopsy, respectively. Possible supplemental analgesia or sedation given on patient request in addition to local anaesthesia and study intervention did not lower pain scores during BMAB. Articaine was not found to be superior to lidocaine as a local anaesthetic. Warming and buffering the lidocaine solution diminished pain during infiltration, but did not lower the pain scores during other phases of BMAB. Sublingual fentanyl (200 µg or 100 µg) did not provide significant pain relief relative to placebo when administered 6 64 minutes before BMAB. Dizziness was a frequent side-effect. Inhalation of 50% N2O in O2 was no more effective than inhalation of 50% O2. No significant differences in adverse effects emerged between patients receiving N2O/O2 and those receiving 50% O2. Interestingly, 86% of N2O patients and 83% of placebo patients would choose the same analgesia method during their next BMAB. Conclusions: Many patients undergoing BMAB suffer intense pain during the procedure. Pre-procedural anxiety was strongly associated with pain during the various phases of BMAB. The pain from local anaesthetic infiltration with articaine and lidocaine was similar. Buffering and warming the local anaesthetic solution clearly reduced the infiltration pain. However, neither these measures nor the use of sublingual fentanyl or inhalation of N2O had an impact on the pain caused by aspiration and biopsy.
  • Pesonen, Anne (Helsingin yliopisto, 2011)
    The proportion of patients over 75 years of age, receiving all different types of healthcare, is constantly increasing. The elderly undergo surgery and anaesthetic procedures more often than middle-aged patients. Poor pain management in the elderly is still an issue. Although the elderly consumes the greatest proportion of prescribed medicines in Western Europe, most clinical pharmacological studies have been performed in healthy volunteers or middle-aged patients. The aim of this study was to investigate pain measurement and management in cognitively impaired patients in long term hospital care and in cognitively normal elderly patients after cardiac surgery. This thesis incorporated 366 patients, including 86 home-dwelling or hospitalized elderly with chronic pain and 280 patients undergoing cardiac surgery with acute pain. The mean age of patients was 77 (SD ± 8) years and approximately 8400 pain measurements were performed with four pain scales: Verbal Rating Scale (VRS), the Visual Analogue Scale (VAS), the Red Wedge Scale (RWS), and the Facial Pain Scale (FPS). Cognitive function, depression, functional ability in daily life, postoperative sedation and postoperative confusion were assessed with MMSE, GDS, Barthel Index, RASS, and CAM-ICU, respectively. The effects and plasma concentrations of fentanyl and oxycodone were measured in elderly (≥ 75 years) and middle-aged patients (≤ 60 years) and the opioid-sparing effect of pregabalin was studied after cardiac surgery. The VRS pain scores after movement correlated with the Barthel Index. The VRS was most successful in the groups of demented patients (MMSE 17-23, 11-16 and ≤ 10) and in elderly patients on the first day after cardiac surgery. The elderly had a higher plasma concentration of fentanyl at the end of surgery than younger patients. The plasma concentrations of oxycodone were comparable between the groups. Pain intensity on the VRS was lower and the sedation scores were higher in the elderly. Total oxycodone consumption during five postoperative days was reduced by 48% and the CAM-ICU scores were higher on the first postoperative day in the pregabalin group. The incidence of postoperative pain during movement was lower in the pregabalin group three months after surgery. This investigation demonstrates that chronic pain did not seem to impair daily activities in home-dwelling Finnish elderly. The VRS appeared to be applicable for elderly patients with clear cognitive dysfunction (MMSE ≤17) and it was the most feasible pain scale for the early postoperative period after cardiac surgery. After cardiac surgery, plasma concentrations of fentanyl in elderly were elevated, although oxycodone concentrations were at similar level compared to middle-aged patients. The elderly had less pain and were more sedated after doses of oxycodone. Therefore, particular attention must be given to individual dosing of the opioids in elderly surgical patients, who often need a smaller amount for adequate analgesia than middle-aged patients. The administration of pregabalin reduced postoperative oxycodone consumption after cardiac surgery. Pregabalin-treated patients had less confusion, and additionally to less postoperative pain on the first postoperative day and during movement at three months post-surgery. Pregabalin might be a new alternative as analgesic for acute postoperative and chronic pain management in the elderly. Its clinical role and safety remains to be verified in large-scale randomized and controlled studies. In the future, many clinical trials in the older category of patients will be needed to facilitate improvements in health care methods.
  • Rönty, Mikko (Helsingin yliopisto, 2008)
    Palladin is a novel actin microfilament associated protein, which together with myotilin and myopalladin forms a novel cytoskeletal IgC2 domain protein family. Whereas the expression of myotilin and myopalladin is limited mainly to striated muscle, palladin is widely expressed in both epithelial and mesenchymal tissues, including heart and the nervous system. Palladin has a complex genetic structure and it is expressed as several different sized and structured splice variants, which also display differences in their expression pattern and interactions. In muscle cells, all the family members localize to the sarcomeric Z-disc, and in non-muscle cells palladin also localizes to the stress-fiber-dense regions, lamellipodia, podosomes and focal adhesions. A common feature of this protein family is the binding to α-actinin, but other interactions are mostly unique to each member. Palladin has been shown to interact with several proteins, including VASP, profilin, Eps8, LASP-1 and LPP. Its domain structure, lack of enzymatic activity and multiple interactions define it as a molecular scaffolding protein, which links together proteins with different functional modalities into large complexes. Palladin has an important role in cytoskeletal regulation, particularly in stress fiber formation and stabilization. This assumption is supported by several experimental results. First, over-expression of palladin in non-muscle cells results in rapid reorganization of the actin cytoskeleton and formation of thick actin bundles. Second, the knock-down of palladin with anti-sense and siRNA techniques or knock-out by genetic methods leads to defective stress fiber formation. Furthermore, palladin is usually up-regulated in situations requiring a highly organized cytoskeleton, such as differentiation of dendritic cells, trophoblasts and myofibroblasts, and activation of astrocytes during glial scar formation. The protein family members have also direct disease linkages; myotilin missense mutations are the cause of LGMD1A and myofibrillar myopathy. Palladin mutations and polymorphisms, on the other hand, have been linked to hereditary pancreatic cancer and myocardial infarction, respectively. In this study we set out to characterize human palladin. We identified several palladin isoforms, studied their tissue distribution and sub-cellular localization. Four novel interaction partners were identified; ezrin, ArgBP2, SPIN90 and Src-kinase.The previously identified interaction between palladin and α-actinin was also characterized in detail. All the identified new binding partners are actin cytoskeleton associated proteins; ezrin links the plasma membrane to the cytoskeleton, ArgBP2 and SPIN90 localize, among other structures, to the lamellipodia and in cardiomyocytes to the Z-disc. Src is a transforming tyrosine kinase, which besides its role in oncogenesis has also important cytoskeletal associations. We also studied palladin in myofibroblasts, which are specialized cells involved in diverse physiological and pathological processes, such as wound healing and tissue fibrosis. We demonstrated that palladin is up-regulated during the differentiation of myofibroblasts in an isoform specific manner, and that this up-regulation is induced by TGF-β via activation of both the SMAD and MAPK signalling cascades. In summary, the results presented here describe the initial characterization of human palladin and offer a basis for further studies.
  • Ainola, Mari (Helsingin yliopisto, 2009)
    Rheumatoid arthritis is the most common of all types of arthritis and despite of intensive research etiology of the disease remains unclear. Distinctive features of rheumatic arthritis comprise continuous inflammation of synovium, in which synovial membrane expands on cartilage leading to pannus tissue formation. Pannus formation, appearance of proteolytic enzymes and osteoclast formation cause articular cartilage and bone destruction, which lead to erosions and permanent joint damage. Proteolytic pathways play major roles in the development of tissue lesions in rheumatoid arthritis. Degradation of extracellular matrix proteins is essential to pannus formation and invasion. Matrix metalloproteinases (MMP) form a large proteolytic enzyme family and in rheumatoid arthritis they contribute to pannus invasion by degrading extracellular matrix and to joint destruction by directly degrading the cartilage. MMP-1 and MMP-3 are shown to be increased during cell invasion and also involved in cartilage destruction. Increase of many cytokines has been observed in rheumatoid arthritis, especially TNF-α and IL-1β are studied in synovial tissue and are involved in rheumatoid inflammation and degradation of cartilage. Underlying bone resorption requires first demineralization of bone matrix with acid secreted by osteoclasts, which exposes the collagen-rich matrix for degradation. Cathepsin K is the best known enzyme involved in bone matrix degradation, however deficiency of this protein in pycnodysostosis patient did not prevent bone erosion and on the contrary pannus tissue invading to bone did not expressed much cathepsin K. These indicate that other proteinases are involved in bone degradation, perhaps also via their capability to replace the role of other enzymes especially in diseases like pycnodysostosis or during medication e.g. using cathepsin K inhibitors. Multinuclear osteoclasts are formed also in pannus tissue, which enable the invasion into underlying bone matrix. Pannus tissue express a receptor activator of nuclear factor kappa B ligand (RANKL), an essential factor for osteoclast differentiation and a disintegrin and a metalloproteinase 8 (ADAM8), an osteoclast-activating factors, involved in formation of osteoclast-like giant cells by promoting fusion of mononuclear precursor cells. The understanding of pannus invasion and degradation of extracellular matrix in rheumatic arthritis will open us new more specific methods to prevent this destructive joint disease.
  • Peura, Matti (Helsingin yliopisto, 2012)
    The skin is the largest organ of the human body. It maintains body homeostasis and provides an essential barrier that protects us from the environment. After injury to the skin, a complex series of tightly controlled responses are initiated to restore its integrity. In large-scale wounds, such as burns, the intrinsic capacity for healing is compromised due to lack of dermal support. Dermal fibroblasts guide crucial re-epithelialization events such as keratinocyte migration and proliferation. Fibroblast-keratinocyte interaction is directed by paracrine factors as well as cell-cell and cell-extracellular matrix contacts. Fibroblasts as well as other mesenchyme-derived cells such as bone marrow stromal cells can produce a vast array of growth factors in vitro. When activated by deprivation of extracellular matrix cell adhesion sites, the cells prefer cell-to-cell contacts, form clusters, and release growth factors. This present work focused on characterizing the use of a combination of growth factors released by mesenchymal cell aggregates, a process designated as nemosis, for treatment of skin wound healing. We used inhibitors of several intracellular signaling pathways to define the migration-inducing mechanisms of nemosis using a keratinocyte wound-healing assay. Model human keratinocytes HaCaT-cells responded to the nemosis-derived conditioned medium with enhanced migration, proliferation, and viability. A c-Met-specific small molecule tyrosine kinase inhibitor as well as an anti-hepatocyte growth factor antibody inhibited these responses. The study aimed to characterize means of improving wound healing by combining biological materials, such as fibrin or recombinant human collagen III with the growth factors to construct a transplantable cell- and growth factor-containing matrix. When we treated porcine partial-thickness wounds with the growth factor-containing fibrin matrix, we observed an increase in the proliferation and migration of hair-follicle and lateral wound-edge keratinocytes. In addition, granulation tissue formation was enhanced when compared with formation on saline-treated wounds. Keratinocyte transplantation in porcine full thickness wounds was feasible with a recombinant human collagen type III matrix. The results presented here indicate that cell-cell contact-activated fibroblasts or bone marrow stromal cells improve keratinocyte transplantation with paracrine factors. Fibrin or recombinant human collagen III can serve as vehicles for delivery of these signals to the target site in acute wounds. Since these factors are also crucial for healing of chronic non-healing wounds, it is likely that our therapeutic approach will be of benefit in their treatment, too.  
  • Björkman, Mikko (Helsingin yliopisto, 2010)
    Serum parathyroid hormone (PTH) and vitamin D are the major regulators of extracellular calcium homeostasis. The inverse association between PTH and vitamin D and the common age-related elevation of the PTH concentration are well known phenomena. However, the confounding or modifying factors of this relationship and their impact on the response of PTH levels to vitamin D supplementation need further investigation. Clinical conditions such as primary hyperparathyroidism (PHPT), renal failure and vitamin D deficiency, characterized by an elevation of the PTH concentration, have been associated with impaired long-term health outcomes. Curative treatments for these conditions have also been shown to decreases PTH concentration and attenuate some of the adverse health effects. In PHPT it has also been commonly held that hypercalcaemia, the other hallmark of the disease, is the key mediator of the adverse health outcomes. In chronic kidney disease the systemic vascular disease has been proposed to have the most important impact on general health. Some evidence also indicates that vitamin D may have significant extraskeletal actions. However, the frank elevation of PTH concentration seen in advanced PHPT and in end-stage renal failure have also been suggested to be at least partly causally related to an increased risk of death as well as cognitive dysfunction. However, the exact mechanisms have remained unclear. Furthermore, the predictive value of elevated PTH in unselected older populations has been less well studied. The studies presented in this thesis investigated the impact of age and mobility on the responses of PTH levels to vitamin D deficiency and supplementation. Furthermore, the predictive value of PTH for long-term survival and cognitive decline was addressed in an unselected population of older people. The hypothesis was that age and chronic immobility are related to a persistently blunted elevation of PTH concentration, even in the presence of chronic vitamin D deficiency, and to attenuated responses of PTH to vitamin D supplementation. It was also further hypothesized that a slightly elevated or even high-normal PTH concentration is an independent indicator of an increased risk of death and cognitive decline in the general aged population. The data of this thesis are based on three samples: a meta-analysis of published vitamin D supplementation trials, a randomized placebo controlled six-month vitamin D supplementation trial, and a longitudinal prospective cohort study on a general aged population. Based on a PubMed search, a meta-analysis of 52 clinical trials with 6 290 adult participants was performed to evaluate the impact of age and immobility on the responses of PTH to 25-OHD levels and vitamin D supplementation. A total of 218 chronically immobile, very old inpatients were also enrolled into a vitamin D supplementation trial. Mortality data for these patients was also collected after a two-year follow-up. Finally, data from the Helsinki Aging Study, which followed three random age cohorts (75, 80 and 85 years) until death in almost all subjects, was used to evaluate the predictive value of PTH for long-term survival and cognitive decline. This series of studies demonstrated that in older people without overt renal failure or severe hypercalcaemia, serum 25-OHD and PTH were closely associated, but this relationship was also affected by age and immobility. Furthermore, a substantial proportion of old chronically bedridden patients did not respond to vitamin D deficiency by elevating PTH, and the effect of a high-dose (1200 IU/d) six-month cholecalciferol supplementation on the PTH concentration was minor. This study demonstrated longitudinally for the first time that the blunted PTH also persisted over time. Even a subtle elevation of PTH to high-normal levels predicted impaired long-term health outcomes. Slightly elevated PTH concentrations indicated an increased risk of clinically significant cognitive decline and death during the last years of life in a general aged population. This association was also independent of serum ionized calcium (Ca2+) and the estimated glomerular filtration rate (GFR). A slightly elevated PTH also indicated impaired two-year survival during the terminal years of frail elderly subjects independently of Ca2+, GFR, and of 25-OHD levels. The interplay between PTH and vitamin D in the regulation of calcium homeostasis is more complex than has been generally considered. In addition to muskuloskeletal health parathyroid hormone is also related to the maintenance of other important domains of health in old age. Higher PTH concentrations, even within conventional laboratory reference ranges, seem to be an independent indicator of an increased risk of all-cause and of cardiovascular mortality, independently of established cardiovascular risk factors, disturbances in mineral metabolism, and renal failure. Limited and inconsistent evidence supports the role of vitamin D deficiency-related lack of neuroprotective effects over the causal association between PTH and impaired cognitive functions. However, the causality of these associations remains unclear. The clinical implications of the observed relationships remain to be elucidated by future studies interfering with PTH concentrations, especially by long-term interventions to reduce PTH.
  • Ray, Carola (Helsingin yliopisto, 2013)
    Daily health behaviours; a balanced diet, sufficient physical activity and night sleep, and limited sedentary behaviour, are essential for children s energy balance as well as for general well-being. Several characteristics in the family are known as determinants for daily health behaviours. Still, many gaps exist in our knowledge. Specific aims of this study were to examine 1) the associations between parent s sense of coherence (SOC) and children s eating habits, 2) whether parental warmth and responsiveness moderate the associations between parenting practices and children s daily health behaviours 3) whether a free school lunch moderates the associations between parenting practices and children s fruit and vegetable intake and 4) whether parenting practices at baseline predict a favorable change in children s daily health behaviours during an 18-month follow-up. This study was based on two data sets. The Hälsoverkstaden study was conducted among 10-to 11-year-old children in the Helsinki region in 2006 (1284 children and 816 parents participated). A follow-up was performed in 2008. The Pro Greens study was conducted in 2009 in 10 countries among 11-year-old children. This study uses data from four countries with two different school lunch policies; Finland and Sweden (n=1775) which serves a free school lunch, and Germany and the Netherlands (n=1405) with no free lunch. This study showed that a stronger parent s SOC was associated with a higher probability that the child had a regular meal pattern; eating daily breakfast, lunch and dinner, more frequent intake of nutrient-dense foods, and less frequent intake of energy-rich foods. The associations between a higher amount of parenting practices and children s regular meal pattern and intake of nutrient-dense foods were stronger when children simultaneously perceived parental warmth and responsiveness. The associations between parenting practices and intake of energy-rich foods and screen time were stronger when children did not perceive warmth and responsiveness from both of their parents. Most of the clusters of fruit and vegetable related parenting practices were more strongly associated with children s intake of raw and cooked vegetables in Germany and the Netherlands, as compared with Finland and Sweden, both of which have free school lunches. Most health behaviours changed unfavourably during the 18-month follow up. Parenting practices predicted such favourable changes in children s daily health behaviours as higher increase in physical activity, less increase in screen time and soft drink intake, and less decrease in fruit intake. This interdisciplinary thesis showed that parenting practices and parents SOC are important determinants and predictors for 10-11 -year old children s daily health behaviours. The contribution to existing knowledge is useful in families, in schools, in health care, when targeting groups with special needs for example overweight children and their families, and in planning and carrying out health policies in order to promote daily health behaviours and healthy weight status development among school-aged children.
  • Helske, Satu (Helsingin yliopisto, 2007)
    Aortic valve stenosis (AS) is an active disease process akin to atherosclerosis, with chronic inflammation, lipid accumulation, extracellular matrix remodeling, fibrosis, and extensive calcification of the valves being characteristic features of the disease. The detailed mechanisms and pathogenesis of AS are still incompletely understood, however, and pharmacological treatments targeted toward components of the disease are not currently available. In this thesis project, my coworkers and I studied stenotic aortic valves obtained from 86 patients undergoing valve replacement for clinically significant AS. Non-stenotic control valves (n=17) were obtained from patients undergoing cardiac transplantation or from organ donors without cardiac disease. We identified a novel inflammatory factor, namely mast cell, in stenotic aortic valves and present evidence showing that this multipotent inflammatory cell may participate in the pathogenesis of AS. Using immunohistochemistry and double immunofluorescence stainings, we found that a considerable number of mast cells accumulate in stenotic valves and, in contrast to normal valves, the mast cells in diseased valves were in an activated state. Moreover, valvular mast cells contained two effective proteases, chymase and cathepsin G, which may participate in adverse remodeling of the valves either by inducing fibrosis (chymase and cathepsin G) or by degrading elastin fibers in the valves (cathepsin G). As chymase and cathepsin G are both capable of generating the profibrotic peptide angiotensin II, we also studied the expression and activity of angiotensin-converting enzyme (ACE) in the valves. Using RT-PCR, imunohistochemistry, and autoradiography, we observed a significant increase in the expression and activity of ACE in stenotic valves. Besides mast cell-derived cathepsin G, aortic valves contained other elastolytic cathepsins (S, K, and V). Using immunohistochemistry, RT-PCR, and fluorometric microassay, we showed that the expression and activity of these cathepsins were augmented in stenotic valves. Furthermore, in stenotic but not in normal valves, we observed a distinctive pattern of elastin fiber degradation and disorganization. Importantly, this characteristic elastin degradation observed in diseased valves could be mimicked by adding exogenous cathepsins to control valves, which initially contained intact elastin fibers. In stenotic leaflets, the collagen/elastin ratio was increased and correlated positively with smoking, a potent AS-accelerating factor. Indeed, cigarette smoke could also directly activate cultured mast cells and fibroblasts. Next, we analyzed the expression and activity of neutral endopeptidase (NEP), which parallels the actions of ACE in degrading bradykinin (BK) and thus inactivates antifibrotic mechanisms in tissues. Real-time RT-PCR and autoradiography revealed NEP expression and activity to be enhanced in stenotic valves compared to controls. Furthermore, both BK receptors (1 and 2) were present in aortic valves and upregulated in stenotic leaflets. Isolated valve myofibroblasts expressed NEP and BK receptors, and their upregulation occurred in response to inflammation. Finally, we observed that the complement system, a source of several proinflammatory mediators and also a potential activator of valvular mast cells, was activated in stenotic valves. Moreover, receptors for the complement-derived effectors C3a and C5a were expressed in aortic valves and in cultured aortic valve myofibroblasts, in which their expression was induced by inflammation as well as by cigarette smoke. In conclusion, our findings revealed several novel mechanisms of inflammation (mast cells and mast cell-derived mediators, complement activation), fibrosis (ACE, chymase, cathepsin G, NEP), and elastin fiber degradation (cathepsins) in stenotic aortic valves and highlighted these effectors as possible pathogenic contributors to AS. These results support the notion of AS as an active process with inflammation and extracellular matrix remodeling as its key features and identify possible new targets for medical therapy in AS.
  • Marbacher, Serge (Helsingin yliopisto, 2014)
    Background and Purpose: Subarachnoid hemorrhage attributable to saccular intracranial aneurysm (IA) rupture is a devastating disease leading to stroke, permanent neurological damage and death. Despite rapid advances in the development of endovascular treatment (EVT), complete and long lasting IA occlusion remains a challenge, especially in complexly shaped and large-sized aneurysms. Intraluminal thrombus induced by EVT may recanalize. The biological mechanisms predisposing IA to recanalize and grow are not yet fully understood, and the role of mural cell loss in these processes remains unclear. To elucidate these processes, animal models featuring complex aneurysm architecture and aneurysm models with different wall conditions (such as mural cell loss) are needed. Materials and Methods: Complex bilobular, bisaccular and broad-neck venous pouch aneurysms were microsurgically formed at artificially created bifurcations of both common carotid arteries in New Zealand rabbits. Sidewall aneurysms were microsurgically created on the abdominal aorta in Wistar rats. Some sidewall aneurysms were decellularized with sodium dodecyl sulfate. Thrombosis was induced using direct injection of a fibrin polymer into the aneurysm. CM-Dil-labeled syngeneic smooth muscle cells were injected into fibrin embolized aneurysms. The procedures were followed up with two-dimensional intra-arterial digital subtraction angiography, contrast-enhanced serial magnetic resonance angiographies, endoscopy, optical projection tomography, histology and immunohistochemistry. Results: Aneurysm and parent vessel patency of large aneurysms with complex angioarchitecture was 90% at one month and 86% at one year follow-up in the bifurcation rabbit model. Perioperative and one month postoperative mortality and morbidity were 0% and 9%. Mean operation time in the rat model was less than one hour and aneurysm dimensions proved to be highly standardized. Significant growth, dilatation or rupture of the experimental aneurysms was not observed, with a high overall patency rate of 86% at three week follow-up. Combined surgery-related mortality and morbidity was 9%. Decellularized aneurysms demonstrated a heterogeneous pattern of thrombosis, thrombus recanalization and growth, with ruptures in the sidewall rat model. Aneurysms with intraluminal local cell replacement at the time of thrombosis developed better neointima, showed less recurrence or growth and no ruptures. Growing and ruptured aneurysms demonstrated marked adventitial fibrosis and inflammation, complete wall disruption and increased neutrophil accumulation in unorganized luminal thrombus. Conclusions: Creation of complex venous pouch bifurcation aneurysms in the rabbit is feasible, with low morbidity, mortality and high short-term and long-term aneurysm patency. They represent a promising approach for in vivo animal testing of novel endovascular therapies. The sidewall aneurysm rat model is a quick and consistent method to create standardized aneurysms. Aneurysms missing mural cells are incapable of organizing a luminal thrombus, leading to aneurysm recanalization and increased inflammatory reactions. These, in turn, result in severe wall degeneration, aneurysm growth and eventual rupture. The results of the presented studies suggest that the biologically active luminal thrombus drives the healing process towards destructive wall remodeling and aneurysm rupture. Local smooth muscle cell transplantation compensates for mural cell loss and reduces recurrence, growth and rupture rate in a sidewall aneurysm rat model.
  • Laine, Mikael (Helsingin yliopisto, 2010)
    Sjögren s syndrome (SS) is a common autoimmune disease affecting the lacrimal and salivary glands. SS is characterized by a considerable female predominance and a late age of onset, commonly at the time of adreno- and menopause. The levels of the androgen prohormone dehydroepiandrosterone-sulphate (DHEA-S) in the serum are lower in patients with SS than in age- and sex-matched healthy control subjects. The eventual systemic effects of low androgen levels in SS are not currently well understood. Basement membranes (BM) are specialized layers of extracellular matrix and are composed of laminin (LM) and type IV collagen matrix networks. BMs deliver messages to epithelial cells via cellular LM-receptors including integrins (Int) and Lutheran blood group antigen (Lu). The composition of BMs and distribution of LM-receptors in labial salivary glands (LSGs) of normal healthy controls and patients with SS was assessed. LMs have complex and highly regulated distribution in LSGs. LMs seem to have specific tasks in the dynamic regulation of acinar cell function. LM-111 is important for the normal acinar cell differentiation and its expression is diminished in SS. Also LM-211 and -411 seem to have some acinar specific functional tasks in LSGs. LM-311, -332 and -511 seem to have more general structure maintaining and supporting roles in LSGs and are relatively intact also in SS. Ints α3β1, α6β1, α6β4 and Lu seem to supply structural basis for the firm attachment of epithelial cells to the BM in LSGs. The expression of Ints α1β1 and α2β1 differed clearly from other LM-receptors in that they were found almost exclusively around the acini and intercalated duct cells in salivons suggesting some type of acinar cell compartment-specific or dominant function. Expression of these integrins was lower in SS compared to healthy controls suggesting that the LM-111 and -211-to-Int α1β1 and α2β1 interactions are defective in SS and are crucial to the maintenance of the acini in LSGs. DHEA/DHEA-S concentration in serum and locally in saliva of patients with SS seems to have effects on the salivary glands. These effects were first detected using the androgen-dependent CRISP-3 protein, the production and secretion of which were clearly diminished in SS. This might be due to the impaired function of the intracrine DHEA prohormone metabolizing machinery, which fails to successfully convert DHEA into its active metabolites in LSGs. The progenitor epithelial cells from the intercalated ductal area of LSGs migrate to the acinar compartment and then undergo a phenotype change into secretory acinar cells. This migration and phenotype change seem to be regulated by the LM-111-to-Int α1β1/Int α2β1 interactions. Lack of these interactions could be one factor limiting the normal remodelling process. Androgens are effective stimulators of Int α1β1 and α2β1 expression in physiologic concentrations. Addition of DHEA to the culture medium had effective stimulating effect on the Int α1β1 and α2β1 expression and its effect may be deficient in the LSGs of patients with SS.
  • Savinko, Terhi (Helsingin yliopisto, 2013)
    Atopic dermatitis (AD) is a common pruritic skin disease with prevalence rates up to 20 % in children and 3 % in adults. Skin barrier defects combined with modified immune responses of the innate and adaptive immune system activate complex pathophysiological pathways that are involved in the development of this disease. AD is characterized by acute flare-ups as well as chronic eczematous pruritic skin lesions and dry skin. It is crucial to clarify the mechanisms underlying AD in order to devise mechanism-based therapeutic approaches. However, the immunological mechanisms participating in AD are far from being completely understood. This thesis investigates mechanisms believed to be involved in atopic skin inflammation by utilizing an AD-like experimental animal model as well as human patients. The AD-like mouse model was also used to examine the model's suitability for evaluating topical medications for treating AD. In addition, this thesis investigates some of the mechanisms in the so-called atopic march. Results highlight new molecular mechanisms involved in AD and the atopic march. Microbial superantigen, derived from Staphylococcus aureus exacerbates the allergen-induced skin inflammation mostly by a mixed Th1/Th2 type inflammation in the presence of both CD8+ and CD4+ T cells and elevated IgE concentrations. This kind of severe inflammation, induced by allergen and superantigen in the murine skin, was declined with topical corticosteroid and calcineurin inhibitor. According to these results, this AD model is both reproducible and suitable for testing novel treatment options in AD. Finally, a recently characterized Th2-promoting cytokine, IL-33, and its receptor, ST2, were investigated in murine models of AD and allergic asthma as well as in human AD and in different cell models. The results obtained from ST2-/- mice suggest that the IL-33/ST2 pathway can regulate innate immune responses and CD8+ T cell mediated responses in the skin and in lung tissue. However, ST2 appeared to be dispensable for the development of Th2 response in the sensitized skin, whereas it was the main inducer of Th2 cytokines in asthmatic airways. Together, these results obtained from the murine model of AD and from the skin of patients with AD reveal new molecular mechanisms involved in AD.
  • Kajander, Kajsa (Helsingin yliopisto, 2008)
    Gastrointestinal symptoms and impaired quality of life caused by irritable bowel syndrome (IBS) affect up to 20% of the adult population worldwide. The exact aetiology and pathophysiology of IBS are incompletely understood. Clinical studies suggest that supplementation with certain probiotics may be beneficial in IBS, but there is not enough evidence to make general recommendations. The aim of this thesis was to investigate microbiota- and mucosa-associated pathophysiological factors of IBS, and to evaluate the long-term effects of multispecies probiotic supplementation on symptoms, quality of life, intestinal microbiota and systemic inflammatory markers in IBS. The intestinal microbiota composition in IBS patients and healthy control subjects was analysed by quantitative polymerase chain reaction (qPCR). Significantly lower counts for the Clostridium coccoides and the Bifidobacterium catenulatum groups were found in IBS compared to controls. Quantitative differences also appeared in subgroup analysis based on the predominant bowel habit: diarrhoea patients harboured significantly lower numbers of Lactobacillus spp. than the constipation-predominant patients, while higher counts for Veillonella spp. were detected in constipation-predominant patients compared to healthy controls. Analysis of mucosal biopsies by a metabolomic approach revealed multiple differences between patients and controls. The most prominent finding was an upregulation of specific lipid species, principally lysophosphatidylcholines and ceramides, in IBS. The effects of multispecies probiotic supplementation with Lactobacillus rhamnosus GG, Lactobacillus rhamnosus Lc705, Propionibacterium freudenreichii subsp. shermanii JS, and Bifidobacterium breve Bb99 or Bifidobacterium animalis subsp. lactis Bb12 was evaluated in two, randomised, double-blind, placebo-controlled trials. Compared to placebo, the probiotic supplementation significantly reduced the total symptoms of IBS. No effects on bowel habit were seen. Health-related quality of life (HRQOL) is reduced in patients with IBS in comparison with the Finnish population on the whole. The probiotic supplementation improved one IBS-specific domain of quality of life (bowel symptoms), whereas no other effects on HRQOL were seen. The probiotics had no major effects on the predominant microbiota as measured by qPCR, but a microarray-based analysis suggested that the probiotic consumption stabilised the microbiota. No effects on serum sensitive-CRP or cytokines were detected. In conclusion, alterations in the microbiota composition and in the mucosal metabolite profile are potential pathophysiological factors of IBS. Multispecies probiotic supplementation alleviates the gastrointestinal symptoms of IBS, and improves the bowel symptoms domain of HRQOL. Probiotic supplementation in IBS is associated with a stabilisation of microbiota, but it does not influence systemic inflammatory markers.
  • Kuusniemi, Arvi-Matti (Helsingin yliopisto, 2007)
    Congenital nephrotic syndrome of the Finnish type (NPHS1) is an autosomal recessive disease which is highly enriched in the Finnish population. It is caused by mutations in the NPHS1 gene encoding for nephrin, which is a major component of the glomerular filtration barrier in the kidney. Patients with NPHS1 have heavy proteinuria and nephrotic syndrome (NS) from birth and develop renal fibrosis in early childhood. Renal transplantation (TX) is the only curative treatment for NPHS1. These patients form the largest group of pediatric kidney transplant children in our country. The NPHS1 kidneys are removed in infancy and they serve as an excellent human material for studies of the pathophysiology of proteinuric kidney diseases. Sustained proteinuria is a major factor leading to end-stage renal failure and understanding this process is crucial for nephrology. In this study we investigated the glomerular and tubulointerstitial changes that occur in the NPHS1 kidneys during infancy as well as the expression of nephrin in non-renal tissues. We also studied the pathology and management of recurrent proteinuria in kidney grafts transplanted to NPHS1 children. Severe renal lesions evolved in patients with NPHS1 during the first months of life. Glomerular sclerosis developed through progressive mesangial sclerosis, and capillary obliteration was an early consequence of this process. Shrinkage of the glomerular tuft was common, whereas occlusion of tubular opening or protrusion of the glomerular tuft into subepithelial space or through the Bowman's capsule were not detected. Few inflammatory cells were detected in the mesangial area. The glomerular epithelial cells (podocytes) showed severe ultrastructural changes and hypertrophy. Podocyte proliferation and apoptosis were rare, but moderate amounts of podocytes were detached and ended up in the urine. The results showed that endocapillary lesions not extracapillary lesions, as generally believed were important for the sclerotic process in the NPHS1 glomeruli. In the tubulointerstitium, severe lesions developed in NPHS1 kidneys during infancy. Despite heavy proteinuria, tubular epithelial cells (TECs) did not show transition into myofibroblasts. The most abundant chemokines in NPHS1 tissue were neutrophil activating protein-2 (NAP-2), macrophage inhibiting factor (MIF), and monocyte chemoattractant protein-1 (MCP-1). Interstitial inflammation and fibrosis were first detected in the paraglomerular areas and the most abundant inflammatory cells were monocytes/macrophages. Arteries and arterioles showed intimal hypertrophy, but the pericapillary microvasculature remained quite normal. However, excessive oxidative stress was evident in NPHS1 kidneys. The results indicated that TECs were relatively resistant to the heavy tubular protein load. Nephrin was at first thought to be podocyte specific, but some studies especially in experimental animals have suggested that nephrin might also be expressed in non-renal tissues such as pancreas and central nervous system. The knowledge of nephrin biology is important for the evaluation of nephrin related diseases. In our study, no significant amounts of nephrin protein or mRNA were detected in non-renal tissues of man and pig as studied by immunohistochemistry and in situ hybridization. The phenotype analysis of NPHS1 children, who totally lack nephrin, revealed no marked impairment in the neurological, testicular, or pancreatic function speaking against the idea that nephrin would play an important functional role outside the kidney. The NPHS1 kidneys do not express nephrin and antibodies against this major glomerular filter protein have been observed in NPHS1 children after renal TX most likely as an immune reaction against a novel antigen. These antibodies have been associated with the development of recurrent NS in the kidney graft of NPHS1 patients. In our study, a third of the NPHS1 patients homozygous for Fin-Major mutation developed recurrent NS in the transplanted graft. Re-transplantations were performed to patients who lost their graft due to recurrent NS and heavy proteinuria immediately developed in all cases. While 73% of the patients had detectable serum anti-nephrin antibodies, the kidney biopsy findings were minimal. Introduction of plasma exchange (PE) to the treatment of recurrent nephroses increased the remission rate from 54% to 89%. If remission was achieved, recurrent NS did not significantly deteriorate the long term graft function. In conclusion, the results show that the lack of nephrin in podocyte slit diaphragm in NPHS1 kidneys induces progressive mesangial expansion and glomerular capillary obliteration and inflicts interstitial fibrosis, inflammation, and oxidative stress with surprisingly little involvement of the TECs in this process. Nephrin appears to have no clinical significance outside the kidney. Development of antibodies against nephrin seems to be a major cause of recurrent NS in kidney grafts of NPHS1 patients and combined use of PE and cyclophosphamide markedly improved remission rates.