Browsing Lääketieteellinen tiedekunta by Publication Year

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  • Karesvuo, Petteri (Helsingin yliopisto, 2021)
    Age-related macular degeneration is the leading cause of visual impairment in developed countries. It is divided into two forms, dry and wet. The etiology of the diseases is still not fully understood. Known risk factors include advanced age, genetics and tobacco smoking. New candidates like Helicobacter pylori, Cytomegalovirus, Chlamydia pneumoniae have been studied but without strong evidence of any association. Low-grade inflammation caused by obesity, for example, places a burden on the eye. We studied one known infection of the tissue supporting the teeth, periodontitis, and its effect on AMD. Surprisingly we found an association between these two diseases in males. Age-related cataract is the leading cause of visual impairment and blindness in developing countries. Cataract operation is one of the commonest procedures in medicine. It brings light to elderly people and greatly improves vision and quality of life. However, there are known complications like posterior capsule opacification (PCO), which puts a burden on healthcare providers and patients alike. Postoperative topical medication is widely used after a cataract operation and drugs are being studied to provide optimal relief of postoperative complications. In our study we found that postoperative topical steroid reduced PCO more effectively than topical NSAID drops. Cataract operations are performed using different types of intraocular lenses (IOL), namely low, intermediate and high diopter IOLs. These lenses can be divided into blue light filtering IOLs and non-blue light filtering IOLs. In animal models blue light has been found to be harmful to the retina, and after the operation there is no longer a crystalline lens to provide protection. The lenses are designed to take this into account and help to protect against wet AMD. We found in our study that low diopter IOLs resulted in more PCO than higher diopter IOLs. We also found no difference between blue light filtering IOLs and non-blue light filtering IOLs in terms of new-onset wet AMD cases. Age-related macular degeneration and cataract often co-exist. The cataract operation induces a small amount of inflammation in the eye and it has been found, albeit with differing results, that cataract operations could activate wet age-related macular degeneration. In our study we found that a cataract operation did not affect wet AMD, its progression or the number of injections needed. New anti-VEGF drugs have revolutionized the treatment of wet AMD. One of the drugs – aflibercept – is frequently used as second-line treatment due to its longer lasting effect and slightly different molecular structure compared with older drug, bevacizumab. We found in our study that aflibercept might provide protection against new-onset visual impairment.
  • Brück, Oscar (Helsingin yliopisto, 2021)
    Histopathology is used in the diagnosis of hematologic malignancies to identify and immunophenotype leukemic cells. However, the surrounding immunologic microenvironment is not characterized in routine clinical practice. This thesis aims to profile immune populations of the chronic (CML) and acute myeloid leukemia (AML) bone marrow (BM) from a T cell perspective. Moreover, we evaluate the potential of machine learning for characterizing molecular genetics and prognosis using H&E stained BM samples of myelodysplastic syndrome (MDS) patients. In study I, we collected diagnostic BM biopsies of 56 chronic-phase CML (CP-CML) patients and 14 control subjects. These were profiled with multiplex immunohistochemistry (mIHC) and image analysis. Compared to control subjects, T cells expressed higher levels of immune checkpoint receptors PD-1, TIM-3 and CTLA-4. PD-1 expression was elevated in the BM compared to PB emphasizing the priority to study BM samples in hemato-oncological research. Moreover, PD-1 expression decreased in T cells during tyrosine kinase (TKI) therapy indicating restoration of the normal immune phenotype. In study II, we collected diagnostic BM biopsies of 52 B-cell acute lymphoblastic leukemia (B-ALL) and 69 AML patients. These were studied with mIHC and image analysis, and the results were combined with data from study I. We could accurately classify AML, B-ALL, CML, and control subjects based on their immunologic profiles. We identified two AML clusters, which contrasted by patient age, T-cell receptor clonality, and prognosis suggesting that patient age could be associated with a distinct clinical phenotype. In study III, we collected BM biopsies of 236 MDS, 87 myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN), and 11 control subjects. We applied convolutional neural networks to examine the spectrum of morphological features. Moreover, we used multivariate regression models to predict the occurrence of genetic aberrations, patient demographics and prognosis. We found that morphological features predict reliably the occurrence of TET2 mutations, spliceosome mutations and chromosome 7 monosomy. The prediction accuracy correlated both with the variant allele frequency and the number of affected genes per pathway. Finally, we identified morphological patterns associated with individual gene and cytogenetic aberrations, patient age, gender, and survival. The thesis shows that leukemic patients form distinct subgroups based on their BM immune microenvironments and their detailed immunoprofiling can help to identify novel prognostic biomarkers. Morever, deep learning -based mining of the BM texture could help to understand the cellular composition and morphology related to molecular genetics profiles.
  • Whipp, Alyce (Helsingin yliopisto, 2021)
    Problems of aggressive behavior affect as many as one in every six children and are associated with negative outcomes for not only the individual themselves, but also their family, friends, and community. Aggressive behavior includes a variety of different behaviors (e.g., yelling, hitting, bullying) and has been notoriously difficult to treat. In assessing aggression, researchers and clinicians have repeatedly been recommended to utilize reports from multiple informants (e.g., parents, teachers, the child him/herself) in order to obtain the most complete picture of the problem. In studying aggressive behavior, early research was initially focused on males only and severe outcomes, but now investigates gender similarities and differences and a broad range of behaviors related to aggression. While much has been learned from research thus far, new biological mechanisms and detailed phenotypic information are still important to continue clarifying the heterogenous nature of aggression and to improve ideas for personalized treatment. Thus, this thesis aimed to contribute to those efforts. Study I and II showed that aggressive behavior (as rated by all raters) often co-occurred with other externalizing behaviors and low prosocial behavior, and also co-occurred with internalizing problems but not as often. Patterns were similar across cohorts and genders, however, parents indicated more co-occurrence with internalizing problems and less co-occurrence with other externalizing behaviors than teachers did. Study III showed teacher and self ratings were able to predict ASPD, both in separate models and when both ratings were in the same model. Additionally, the direct aggression subtype (e.g., hitting, yelling) was able to predict ASPD well, for both genders. Furthermore, when the co-occurring influence of hyperactivity was removed from the aggression ratings (using a residual aggression variable with hyperactivity co-occurrence removed), aggressive behavior was still able to predict ASPD. Study IV showed the ketone body 3-hydroxybutyrate to be negatively associated with aggressive behavior in initial analyses. In more detailed modeling, nearly all raters of aggression showed the same trend with 3-hydroxybutyrate, including in fully adjusted models. In a model including both teacher and self ratings, 3-hydroxybutyrate was significantly associated with both aggressive behavior ratings. A replication dataset of young adult Dutch twins (N=960) showed support for the association found in FinnTwin12, however, the issue of whether there are gender differences of the association of 3-hydroxybutyrate with aggressive behavior remains to be clarified by future research. These findings help to clarify the co-occurrence of aggressive behavior with other behaviors across raters and countries, to show how common the co-occurrence is and that it should be taken into consideration when studying aggressive behavior, including from (epi)genetic or biological perspectives. Additionally, aggressive behavior, in particular direct aggression, can inform future ASPD risk, and obtaining behavior data from teachers and the child are of high importance. Furthermore, the new association of 3-hydroxybutyrate with aggressive behavior suggests new biological pathways to investigate to improve our understanding of aggressive behavior, including potential treatments. This thesis provides refinements to the aggressive behavior phenotype, new avenues for aggression biology investigations, and ideas for where to improve or personalize treatment options.
  • Salmela, Jatta (Helsingin yliopisto, 2021)
    Obesity is a major and growing public health problem in Finland and worldwide. The burden of obesity is unequally distributed between socioeconomic groups, however. In Finland, socioeconomic differences in obesity have persisted over decades. To reduce socioeconomic inequalities in obesity, understanding the trajectories behind these differences is crucial. This study aimed to examine the associations of childhood disadvantage (Sub-study I), changes in adult economic circumstances (Sub-study II), and intergenerational social mobility (Sub-study III) with body mass index (BMI) trajectories in a Finnish occupational cohort. I derived the data from the Helsinki Health Study cohort, which consists of four questionnaire surveys. In Phase 1 (2000–2002), the participants were 40–60-year-old employees of the City of Helsinki, Finland (n=8,960, response rate 67%). The follow-up surveys were conducted in 2007 (n=7,332), 2012 (n=6,809), and 2017 (n=6,832) (response rates 83%, 79%, and 82%, correspondingly). Childhood disadvantage comprised the retrospective measures of parental education and seven types of childhood adversity. I measured changes in adult economic circumstances by household income and experienced economic difficulties (Phases 1–4). Intergenerational social mobility was based on parental and participant’s own education. I calculated BMI from self-reported height and weight (Phases 1–4 and at the age of 25) and analysed the BMI trajectories using group-based trajectory modelling and mixed-effects linear regression. I examined changes in economic circumstances within the BMI trajectory groups using sequence analysis. Other statistical methods included multinomial logistic regression and chi-squared tests. For both genders, low parental education increased the odds of belonging to the trajectory groups of developing overweight and obesity. Experiencing peer bullying and accumulation of adversities in childhood among women, and parental alcohol problems among men, increased the odds of belonging to the trajectory groups of developing obesity. Economic disadvantage was constantly more common in the higher BMI trajectory groups (i.e., groups of overweight and obesity) during Phases 1–4. Differences in household income increased over time between the BMI trajectory groups, and changes in experienced economic difficulties were more common in the higher BMI trajectory groups. Intergenerationally stable low socioeconomic position, but also downward social mobility among men, were associated with the highest BMI trajectory levels. However, birth cohort impacted how upward and downward social mobility were associated with the BMI trajectories. The lowest BMI trajectory levels were found for the groups of stable high socioeconomic position among both genders and birth cohorts. The findings of this study indicate that socioeconomic disadvantage both in childhood and adulthood may predispose an individual to unhealthy weight gain over adulthood. Since socioeconomic disadvantage remains intergenerationally inherited in Finland, obesity prevention should be enhanced among people with unfavourable socioeconomic backgrounds. Additionally, targeted workplace interventions might reduce the existing socioeconomic gradient in obesity among employees, given that substantial increases in BMI were observed during working age. Nevertheless, to tackle socioeconomic inequalities in weight gain more broadly, several societal-level and multidisciplinary policies and actions are highly needed.
  • Danni, Reeta (Helsingin yliopisto, 2021)
    Purpose: To understand better the factors affecting the development of retinal complications after cataract surgery, namely pseudophakic cystoid macular oedema (PCME), in diabetic patients. The study was divided into three parts. The first study (I) aimed to shed light on the effect of systemic vasoactive medication on the risk of PCME. The second study (II) looked at the outcomes of uneventful cataract surgery in diabetic patients without retinal complications to assess whether diabetes itself serves as an independent risk factor for PCME. The third study (III) evaluated the preoperative medication of diabetic patients, specifically the importance of anti-inflammatory treatment in the eyes of diabetic patients. Methods: I. This study is a post hoc analysis of two consecutive prospective clinical studies (Ylinen et al., 2017, 2018b). A total of 269 eyes undergoing routine cataract surgery were studied. Spectral‐domain optical coherence tomography (OCT) imaging was performed before surgery and at 28 days. The patients were given postoperatively either dexamethasone, a nonsteroidal anti‐inflammatory drug (NSAID), or a combination of dexamethasone and NSAID. The effect of systemic vasoactive medication, namely angiotensin-converting enzyme inhibitors-/-angiotensin II receptor antagonists (ACE inhibitors/AT2 antagonists), beta-blockers (β‐blockers), calcium channel blockers (CCBs), nitrates or lipophilic HMG-CoA reductase inhibitors (statins), on the change in central retinal thickness (CRT) after cataract surgery was examined. II. This study is a post hoc treatment analysis using data from two double-masked RCTs (Ylinen et al., 2018a; Ylinen et al., 2018b). A total of 276 eyes of 266 patients undergoing routine cataract surgery were admitted to the study. Patients with type I or II diabetes were compared to nondiabetics. Clinical evaluation and outcome measures were conducted before surgery and on day 28. Patients were treated postoperatively with either steroids, NSAIDs, or their combination. The outcomes were analyzed according to the presence of diabetes. III. This study is a prospective randomized clinical trial with 103 eyes of 103 patients with diabetes undergoing routine cataract surgery. The patients were randomized into two groups: 1) no preoperative anti-inflammatory medication or 2) preoperative topical anti-inflammatory medication with a combination of prednisolone acetate and nepafenac. All eyes received postoperative anti-inflammatory combination therapy for three weeks. Recovery from surgery was recorded using a structured home questionnaire. Clinical outcome parameters were recorded at 28 days and three months. Results: I. In eyes with steroid monotherapy (N = 135), concomitant systemic medication with β‐blockers (12.9 ± 24.0 µm versus 28.6 ± 59.5 µm, P=0.045), CCBs (12.0 ± 22.1 µm versus 26.3 ± 55.6 µm, P=0.041) and statins (12.9 ± 22.8 µm versus 30.0 ± 61.9 µm, P=0.038) attenuated a change in CRT when compared to patients not receiving systemic medication. In multivariable analysis, the use of CCBs proved to be an independent protective factor against macular swelling at 28 days (-0.23; 95% CI [-0.43 to -0.04]; P=0.021). In eyes with NSAID monotherapy (N = 67) and those with steroid and NSAID combination therapy (N = 67), the CRT increase was moderate both with and without the use of systemic medication. Changes in vision remained insignificant. II. In eyes with steroid monotherapy (N = 64), CRT increased more in nondiabetic than in diabetic patients (38.1 ± 72.8 µm versus 7.8 ± 6.6 µm, P=0.010). In eyes with NSAID monotherapy (N = 157), CRT increased less in nondiabetic than in diabetic patients (5.7 ± 18.4 µm versus 6.2 ± 20.5 µm, P=0.897). In eyes with steroid and NSAID combination therapy (N = 55), CRT increased more in nondiabetic than in diabetic patients (3.6 ± 4.1 µm versus 2.9 ± 3.2 µm, P=0.606). At 28 days post-surgery PCME was reported in eight eyes, of which seven were in nondiabetic patients (P=1.000). III. At 28 days, CRT increased more in eyes without preoperative treatment than in eyes with preoperative treatment (2.2 ± 20.2 µm versus 0.1 ± 25.2 µm, P=0.670). At three months, the respective CRT change from baseline was greater with preoperative treatment (-1.5 ± 26.9 µm versus -3.4 ± 26.2 µm, P=0.762). None of the eyes in either group were reported to have PCME. The change in vision remained insignificant. Conclusions: I. Systemic vasoactive medication, CCBs in particular, may protect against CRT change induced by cataract surgery in eyes at risk of PCME, such as those receiving postoperative steroid monotherapy. II. Diabetic patients showed less change in CRT than controls on steroid monotherapy. Other outcome measurements showed no statistical differences. III. Lack of preoperative anti‐inflammatory treatment does not impair recovery from surgery or predispose diabetic patients to increased risk of PCME in eyes postoperatively treated with combination therapy of prednisolone acetate and nepafenac.
  • Björkenheim, Robert (Helsingin yliopisto, 2021)
    Background and aim The treatment of bone defects is challenging regardless of the aetiology of the defect. Traditionally, long-bone defects are treated with autologous bone grafting, vascular bone grafting, distraction osteogenesis, or with tumour prosthesis techniques. New treatment modalities are emerging and the induced membrane technique (Masquelet technique, IMT) has been presented to treat large long-bone defects. The IMT is a two-staged surgical procedure where the induced membrane is regarded as the key element. In the first stage, the bone defect area is carefully debrided, supplemented with proper soft-tissue reconstruction, and filled with a polymethylmetacrylate (PMMA) spacer. This PMMA spacer induces the formation of a foreign body membrane around the bone defect, i.e. an induced membrane (IM). The IM conveys neovascularization to the bone defect site, isolates the bone defect site hindering bone graft resorption, serves as a source of mesenchymal stem cells (MSC), and provides an osteogenic stimulative effect via secretion of bone morphogenic proteins (BMP). In the second stage, typically 4 to 8 weeks after the initial surgery, the IM is carefully incised, the PMMA spacer removed, and the defect filled with autologous bone graft. To replace the two-staged procedure and to eliminate the need for autologous bone grafting, we developed a bioactive glass (BAG) scaffold by sintering BAG-S53P4 granules for use in a single-stage IMT without the need for autologous bone graft. Furthermore, selected scaffolds were coated with poly(DL-lactide-co-glycolide) (PLGA) to increase the mechanical properties of the scaffold and to potentially induce a more potent IM compared to BAG-S53P4 alone. We sought to introduce a BAG scaffold that can induce a membrane similar to PMMA and that allows bone formation at the bone defect site in the metaphyseal area of a long bone. Materials and methods The present study consists of in vitro and in vivo evaluations of BAG-S53P4(±PLGA) scaffolds. The in vitro study was conducted on macrophages and MSCs to evaluate the immunomodulatory and osteogenic effects of BAG scaffolds. The in vivo study was conducted on New Zealand White (NZW) rabbits to assess IM formation and bone formation in a bone defect model located in the metaphysis of a long bone. Results The BAG-S53P4 scaffolds demonstrated a clear immunomodulatory and osteogenic effect on macrophages and MSCs, respectively, and this effect was attenuated by the PLGA coating. The in vitro results of osteogenic ability were similar as those from the in vivo experiments in rabbits. New bone formation was observed in BAG-S53P4(±PLGA) scaffolds at the 2-week timepoint, and bone formation increased during the 8-week follow up. The IMs of PMMA and BAG-S53P4(±PLGA) had a similar appearance in microscopic evaluations throughout follow up. The aforementioned IMs were less fibrotic and displayed more abundant capillary formation than control samples during follow up. The highest number of capillaries at the 8-week timepoint was observed in BAG-S53P4-PLGA IMs. The IMs of BAG-S53P4(±PLGA) showed similar or superior mRNA expression rates when compared with PMMA IMs regarding tumour necrosis factor alpha (TNFα), vascular endothelial growth factor (VEGF), and BMP-2, -4, and -7. Conclusion In this study, the sintered BAG-S53P4(±PLGA) scaffold addresses the key requirements of successful bone regeneration in the metaphyseal area of long bones, namely sintered BAG-S53P4(±PLGA) scaffolds are osteoconductive; induces a membrane that serves as a source of inflammatory mediators and growth factors; has the capacity to stimulate MSCs towards osteogenic differentiation (osteostimulation); and immunomodulates inflammatory cells that can possibly be tailored for a specific clinical need. Thus, BAG-S53P4(±PLGA) scaffolds demonstrate the requisite properties for potential use as a bone graft substitute in a IMT performed in a single-stage fashion.
  • Laukkanen, Kirsi (Helsingin yliopisto, 2021)
    Cutaneous T-cell lymphomas (CTCLs) constitute an incurable, chronic, heterogeneous group of non-Hodgkin lymphomas, characterized by a malignant population of mature T-lymphocytes that infiltrate the skin. The incidence of CTCLs has increased worldwide. Symptoms vary from indolent skin patches to aggressive skin tumors. In addition to the skin, lymph nodes, blood, and other body organs are affected depending on the stage and subtype of the disease. Difficulties in differentiating early symptoms from other skin conditions and complex diagnostic criteria make CTCLs challenging to diagnose, often delaying the diagnosis for years. Despite intensive research, the pathogenesis of CTCLs remains mostly unknown. This study emphasizes the impact of the tumor microenvironment (TME) and the tumor cell-released extracellular vesicles (EVs) on the pathogenesis of CTCLs. Particularly, this study examines the role of the tryptophan pathway-associated enzymes indoleamine 2,3-deoxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO). IDO induces immune tolerance in the TME by inflammation and T-cell activation. While TDO catabolizes the same metabolic pathway as IDO1, its role in tumors is poorly characterized. We showed that both IDO1 and TDO are expressed in CTCL tissues and cell lines. Interestingly, different CTCL subtypes show unique patterns of expression. In addition, elevated serum kynurenine/ tryptophan ratios observable in plasma samples of mycosis fungoides (the most common subtype of CTCL) patients correlated with advanced disease. Furthermore, four tryptophan catabolic route metabolites were upregulated, and two were downregulated. These observations could be exploited in clinical tests, and therapeutic potential for CTCLs may result from blocking IDO activity. EVs are small membranous vesicles released into the extracellular milieu by most cell types – also by cancer cells. The EVs released from cancer cells contain various proteins, lipids, amino acids, and metabolites and have proven to be an essential form of intercellular communication. Malignant cells can release EVs into TME and the circulation to reprogram target cells or prepare a pre-metastatic niche. Such transfer could occur at a very early stage in tumor progression because the small size of EVs allows them to cross barriers that cells cannot. Consequently, the molecular cargo of EVs reflects the cell of origin, which is also detectable in the circulation by the non-invasive liquid biopsy method. This study shows that human endogenous retrovirus, type W (HERV-W)-coded syncytin-1 in CTCL cells and CTCL cell-derived EVs is upregulated. Functionally, upregulated syncytin-1 can promote cell-to-cell fusion. Cell-to-cell fusion in cancers can induce genomic instability and aneuploidy and contribute to tumor heterogeneity, drug resistance, and metastasis. Although the molecular mechanisms of EVs are not fully characterized, syncytin-1 could be involved in binding EVs to target cells to facilitate the progressing fusion. Our functional study suggested that EV-harbored syncytin-1 promoted giant plasma membrane-surrounding fusion cells in the recipient T-cell leukemia cells. In addition, we studied alterations of EV-derived metabolite cargo in CTCL, prostate carcinoma, and colon carcinoma cell lines and compared these with the cargo of their healthy counterparts. In cancers, the expression of metabolites is commonly reregulated due to oncogenes or tumor suppressor mutations. The enhanced metabolism supports cancer cell proliferation and survival. Previously, numerous cancer-associated metabolites have been detected, but little is known of their role in cancer-derived EVs. This study shows that despite the differences among the studied cancer types, all cell line-derived EVs shared a common metabolomic feature: upregulation of proline and succinate. In addition, in CTCL- and prostate cancer-derived EVs, folate and creatinine were upregulated. This doctoral thesis explores the role of EVs and the kynurenine pathway in the pathogenesis of CTCLs. These observations could impact diagnosis and have therapeutic value for currently incurable, complex CTCLs. In addition, our results from three different cancer cell line-derived EVs show that metabolomic reprogramming of cancer cells influences the EV metabolome. In particular, this finding suggests that proline, succinate, folate, and creatinine could constitute a metabolomic fingerprint of cancer, which could serve as a peripherally detectable cancer marker. Thus, exploring the function of EVs in cancer progression will prove valuable in next-generation cancer diagnosis and treatment.
  • Peltonen, Kati (Helsingin yliopisto, 2021)
    Concussion is a common injury in high velocity sports such as ice hockey. The importance of appropriate identification, evaluation and management of concussions has been emphasized to avoid more severe injuries and long-term consequences and premature retirements. Adolescent athletes are more prone to concussion than adults, and concussion may cause severe acute and long- term complications in the developing athletes. The initial recognition and evaluation of concussion occurs acutely on the scene of injury. Some observable on-field signs that are thought to indicate concussion diagnosis are loss of consciousness (LOC), amnesia, disorientation, postural instability, and vacant look. A multifaceted approach is recommended for concussion evaluation. The neuropsychological assessment is mentioned as the “cornerstone” of concussion management even if it is insufficient alone. It is important to model the typical cognitive performance and development and to provide reference values for clinicians in order for them to identify atypical brain function after injury. The general aim of the present study was to examine the cognitive performance and post-injury cognitive decline of adolescent athletes. The study’s objective was to explore the association between on-field signs of concussion and postinjury neurocognitive deficits. An additional aim was to examine the modifying factors in concussion assessment such as age, concussion history, learning disability and repeated testing. This thesis comprises three studies exploring the neurocognitive performance of adolescent athletes pre- and postinjury using the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery. The first study examined the interaction effects of age, learning disability (LD), and previous concussion history on cognitive performance at a baseline in a sample of 1823 Finnish adolescent athletes. The second study explored the usefulness of on-field signs of concussion (i.e., LOC, amnesia, disorientation, postural instability, and vacant look) for predicting worse-than baseline neurocognitive performance during the acute, postinjury period in a sample of 34 concussed young athletes. The third study further examined the effects of on-field signs on the rate of acute neurocognitive decline in a sample of 32 concussed participants using reliable change indices (RCIs) derived from a healthy sample of 312 athletes. Compared to typically developing athletes, athletes with LD had lower neurocognitive scores across all domains in a preseason baseline assessment. Additionally, athletes with LD demonstrated atypical maturational trajectories in verbal memory and visual motor speed. The number of prior concussions did not affect neurocognitive performance at the baseline. Hierarchical regression analyses were utilized to examine the predictive value of on-field signs for postinjury cognitive recovery. On-field LOC, amnesia and vacant look were related to larger deficits in cognition at 7 days postinjury compared to concussed adolescent athletes without these signs. LOC accounted for 22% of the variance in verbal memory performance, and amnesia accounted for 15% of variance in verbal memory performance at group level. Vacant look sign accounted for 9% of the variance in visual memory scores. The effect of acute signs of concussion on postinjury cognitive functioning was further explored using RCI methodology. RCI methodology was applied to determine whether the change between baseline- and postinjury-cognitive functioning is meaningful at the individual level. The 1-year test-retest reliability of the Finnish version of ImPACT ranged from .39 to .71. RCIs derived from a healthy sample were calculated and applied to concussed sample. Athletes with an acute LOC, amnesia, or postural instability were approximately 8 times more likely to have impairments in two or more cognitive areas evaluated by ImPACT on day 3 postinjury. Acute on-field disorientation or a vacant look did not lead to reliable cognitive decline. In all, the findings of the present study suggest that cognitive functioning develops throughout adolescence and that athletes with LD differ from their counterparts in cognitive maturational trajectories. Separate reference values for LD athletes are needed, considering their unique cognitive development. Baseline testing might be beneficial in subpopulations such as youth athletes and athletes with LD that display large variability in cognitive performance or differing developmental trajectories over time. Based on the present study, the presence of LOC, amnesia, or vacant look are risk factors for longer recovery times. The presence of acute postural instability might also indicate a more severe injury that warrants an intensive cognitive follow-up. The present findings have direct implications for concussion recognition, evaluation, and management. Reference values and reliable change indices for Finnish language and culture are provided for youth athletes and can be directly implemented in real-life situations. Overall, this study adds valuable information about the neurocognitive performance of youth athletes.
  • Heikkilä, Nelli (Helsingin yliopisto, 2021)
    The human immune system protects the body from infective microorganisms as well as from genetically altered self-cells that can develop to cancer. Meanwhile, the immune system needs to remain unreactive towards healthy tissues of self to prevent the development of autoimmune diseases such as type 1 diabetes. The immune system is divided into innate and adaptive immunity. The function of the innate immunity is based on the recognition of general properties of different pathogens and the sensing of tissue damage. Innate responses rise rapidly and remain unchanged with repeated encounters with the same pathogens. In contrast, the adaptive immunity uses special antigen receptors to recognize specific structures of pathogens. It also helps the other immune cells to mount qualitatively appropriate responses. Upon the first encounter with a pathogen the cells of the adaptive immunity are naive, and the adaptive responses develop slowly but some cells form memory cells that mount responses rapidly at the re-encounter with the same pathogen. The adaptive immune system consists of T cells and B cells. This thesis addresses T-cell diversity focusing on their antigen receptors, i.e. T-cell receptors (TCR), as well as on the characteristics of the memory T-cell subsets. T cells develop in the thymus, where each T cell assembles its unique TCR from TCRα and TCRβ chains or from TCR and TCR chains that are generated with random recombination of receptor gene segments. In theory the potential TCR repertoire diversity generated with TCR recombination reaches 1015–1020 unique TCRs. In this thesis we sequenced TCR and TCR repertoires in human thymus samples obtaining on average 3.7 million unique TCRα and 10.3 million unique TCRβ chains in one individual. We used mathematical diversity estimators that suggested the total thymic TCR diversity to be 60–100 million unique TCRα chains and 40–60 million unique TCRβ chains. Considering the vast diversity of TCRs, it is very unlikely to detect identical TCR chains in multiple individuals. However, analysis of repertoire overlaps between different individuals showed that on average 47% of TCRα chains and 6% of TCRβ chains are shared between individuals. A pair of monozygotic twins was included in our thymus samples allowing us to estimate the genetic input in the generation of TCR repertoires. The influence of the genetic background in the generation of the TCR repertoire was the clearest in the recombination itself but the genetic signal decreased at the later stages of T-cell development. To identify the potential antigenic targets of TCR chains that were abundantly produced in the thymus, we compared the thymic TCR repertoires and TCRs with well-defined antigenic targets described in the literature. Surprisingly, the thymus produced more abundantly TCRα chains that were associated with the recognition of pancreatic islet antigens and with the pathogenesis of type 1 diabetes than TCRα chains associated with recognition of human immunodeficiency virus (HIV) antigens. These abundantly produced TCRα chains recognizing self-tissues could potentially be exploited in the development of interventions to prevent type 1 diabetes or even other autoimmune diseases. Besides the individual TCRs the T-cell diversity is manifested in the functional T-cell subsets. Understanding their heterogeneity is indispensable in developing medical treatments that target T cells. The majority of research with human immune cells relies on blood samples, though the circulation merely represents a route of transit for T cells and most of them reside in tissues. In this thesis we used flow cytometry to analyze naive T cells and different memory T-cell subsets in blood, lymph nodes, spleen and ileum. Our results indicate that naive T cells and long-lived stem cell -like memory T cells, which are thought to maintain other memory populations, principally reside in blood and lymph nodes. In addition, their numbers decreased along aging. The spleen and particularly the ileum host more mature and short-lived memory populations. The comparison of TCR repertoires in naive and different memory T-cell subsets suggested that T-cell maturation drives convergent repertoire development in unrelated individuals. Our results help to understand how and which part of T-cell populations the future therapeutic interventions should target so that they interfere only minimally with the homeostasis of other T-cell populations.
  • Turtinen, Maaret (Helsingin yliopisto, 2021)
    Type 1 diabetes (T1D) is an immune-mediated disorder characterized by autoimmunity to pancreatic beta cells and progressively leading to acute onset of hyperglycemia and dependence on exogenous insulin. Finland has the highest incidence of T1D worldwide. In high-incidence countries, the disease affects more males than females. The risk of developing T1D can be assessed based on human leucocyte antigen (HLA) genotypes alone or in combination with non-HLA genetic polymorphisms and by following the development of diabetes-associated autoantibodies. The disease risk is higher in the family members of patients with T1D compared to the general population. The etiology of T1D is believed to be multifactorial and involves both genetic and environmental factors. Moreover, there is heterogeneity in the disease pathogenesis and progression, and this might be associated with the variability in the phenotype and genotype of T1D at clinical disease presentation. This thesis aimed to describe disease severity at diagnosis of T1D characterized by metabolic, immunological and genetic factors associated with sex, family history of diabetes and seasonal timing of the disease manifestation. The study subjects in this thesis are participants in the Finnish Pediatric Diabetes Register and Sample Repository. HLA genetics and diabetes-related autoantibodies were analyzed soon after the diagnosis of T1D. A structured questionnaire is used for collecting information on the metabolic decompensation at diagnosis and on the family history of any type of diabetes in first-degree relatives (FDR) and grandparents. This thesis assessed the characteristics at diagnosis in 4993 Finnish children and adolescents newly diagnosed with T1D between 2003 and 2016. Family history of T1D was reported in 10.4% of all children, and fathers were more commonly affected than mothers or siblings (5.1% vs. 2.8% vs. 1.9%). The presence of paternal T1D was associated with a more severe disease phenotype at diagnosis of T1D compared to a history of maternal T1D, which has not been reported earlier. A male preponderance was observed among the parents diagnosed before the birth of the index child, while the male-female ratio was similar in the parents diagnosed after the birth of the index child, which support the idea of a protective effect of maternal type 1 diabetes via insulin treatment during pregnancy. Genetic factors may also partly explain the phenomenon, as the high-risk HLA haplotype DR4-DQ8 was more prevalent in familial vs. sporadic cases and especially in children with an affected father. Two percent of the index children reported type 2 diabetes (T2D) in their FDRs, the corresponding proportion for grandparents being 36%. Fathers and grandfathers were more commonly affected with T2D than mothers and grandmothers. Family history of T2D seemed to present with a mixed phenotype of both major types of diabetes associated features, as it was associated with older age at diagnosis, higher BMI z-score and more frequent autoantibody negativity. Girls seemed to have poorer glycemic control and signs of a more severe metabolic derangement at the diagnosis of the disease. Boys, however, more often tested positive for three of four biochemical autoantibodies (IAA, IA-2A, and ZnT8A) while only GADA positivity was more common in girls. Significant seasonality in T1D onset was observed with higher frequency of new diagnoses in fall and winter. The youngest children (aged 0.5–4 years), however, differed from older children as the minority of them were diagnosed in winter, suggesting that different environmental factors may play a key role at different ages. Poorer metabolic decompensation was associated with seasons with the lowest number of diagnoses and is more likely to be explained by a delay in seeking medical help or the reduced medical services during summer holidays than by a more aggressive autoimmunity. This thesis provides updated information on the prevalence of T1D and T2D among the family members of newly diagnosed Finnish children with T1D. The observed frequencies are in line with previous reports. In addition, this thesis improves the identification of patients with the highest risk of an aggressive disease process at the diagnosis of T1D. The disease features at the time of diagnosis may also predict later glycemic control and risk of long-term complications. The early recognition of factors related to a more adverse disease course may help us to create future strategies for disease management and prevent later disease-related complications. Future studies with prospective follow-up after the diagnosis are required to confirm these assumptions. Furthermore, our results emphasize heterogeneity in the disease etiology and pathogenesis. In the future, a more accurate diagnosis and individualized treatment methods should be used in the care of children and adolescents affected by T1D.
  • Sane, Markus (Helsingin yliopisto, 2021)
    Pulmonary embolism (PE), together with deep venous thrombosis (DVT), is the main manifestation of venous thromboembolism (VTE). Initial activation of the coagulation system, necessary for the development of VTE, is assumed to occur mainly in the venous valves of the lower extremity veins. The clinical manifestations of VTE vary widely from an asymptomatic incidentally detected distal DVT to a life-threatening extensive PE, but the factors regulating its extent are known only partially. Also, data regarding the reflection of the dynamic thrombotic process on several plasma markers of haemostasis are scarce. The aims of this thesis were to evaluate the time-dependent effects of acute PE on plasma levels of haemostatic markers (study I), how VTE extent, PE localization, concomitant DVT and plasma levels of haemostatic markers are related (studies II and III), and the PE mortality trends in Finland during the last 20 years (study IV). The cohort that was analysed in studies I–III consisted of 63 PE patients and 15 healthy controls. Laboratory analyses of the plasma levels of haemostatic markers (e.g. D-dimer, factors V (FV), VIII (FVIII) and XIII (FXIII), von Willebrand factor antigen (vWF:Ag), soluble thrombomodulin) were performed in the acute phase shortly after diagnosis and in the stable phase 7 months later. Intraindividual comparisons were made between the two time points, as well as comparisons with healthy controls. In conclusion, in studies I–III it was seen that acute PE causes changes to analysed haemostatic markers (plasma levels of FXIIIa and vWF:Ag), and significant negative correlation between FV plasma level and platelet count with VTE volume was also seen. Interestingly, preceding antiplatelet therapy was associated with smaller VTE volume. The coexistence of DVT in these PE patients was associated with a more central location of the PE, but the analysed haemostatic markers and patient characteristics were similar between patients with or without coexisting DVT. In study IV, we analysed the data on PE mortality in Finland during 1996–2017 from the death certificate archive – a registry maintained by Statistics Finland. Overall, PE mortality decreased by almost 28% during follow-up and the decrease was twofold in females compared with males. The impact of the population-level autopsy rate on detected PE mortality was evaluated and a statistically significant association was seen. Interestingly, the annual PE mortality decreased as much in the period when the autopsy rate remained unchanged (1996–2009) as in the period when the autopsy rate started to decline rapidly (2010–2017), but when the impact of the decrease in the autopsy rate was estimated, the PE mortality plateaued in 2009.
  • Lindholm, Juha-Matti (Helsingin yliopisto, 2021)
    This study was undertaken to advance the treatment and prevention of common postoperative complications of cataract surgery. Study I aimed to compare the efficacy, safety, and tolerability of a subconjunctival injection of triamcinolone acetonide with topical dexamethasone eye drops for the prevention of inflammation and macular edema after cataract surgery. Study II was carried out to evaluate the real-world cumulative incidence and risk factors of Nd:YAG capsulotomy. Study III attempted to assess the risk of Nd:YAG capsulotomy in association with myopia and the diopter power of the implanted intraocular lens (IOL). Study IV focused on the potential for improving the Nd:YAG treatment process with the help of Lean methodology. I. Treatment with perioperative 20 mg subconjunctival injection of triamcinolone acetonide was found to be effective for the prevention of inflammation and macular edema. It was shown non-inferior to topical dexamethasone and may prevent pseudophakic cystoid macular edema more successively. The mean change in central retinal thickness at 28 days was higher with topical dexamethasone compared to triamcinolone (difference +27.1 μm; 95% confidence interval (CI): +7.28 μm to +47.0 μm; p = 0.008). Corrected distance visual acuity and intraocular pressure (IOP) changes were similar, and ocular tolerance was good in both groups. No serious adverse events were observed. II. The 5-year cumulative incidence of Nd:YAG capsulotomy after cataract surgery was estimated at 13.2% (95% CI: 12.5%–14.0%) with competing risks methodology for common hydrophobic acrylic IOLs. Real-world evidence of this retrospective cohort study of 10,044 eyes suggested that implantation of SN60WF and ZA9003 IOLs was associated with lower risk compared to ZCB00, after accounting for other predictors. Increased risk of Nd:YAG capsulotomy was associated with the eyes of patients aged younger than 60 years, female sex, and eyes implanted with an IOL of <22.5 diopters power. III. The 5-year cumulative probability of Nd:YAG capsulotomy after cataract surgery was 27.4% (95% CI: 22.9–32.6%) for low-diopter (5–16.5 D) IOLs, 14.6% (95% CI: 13.8–15.5%) for mid-diopter (17–24.5 D) IOLs, and 13.6% (95% CI: 11.7–15.6%) for high-diopter (25–30 D) IOLs. Results showed that low-diopter IOLs are associated with a significantly higher risk of Nd:YAG capsulotomy within five years following implantation. Estimation should help in evaluating the risks of cataract surgery in myopic eyes. IV. This study described a Lean-oriented process improvement project to develop a streamlined Nd:YAG capsulotomy treatment protocol. The improved treatment protocol was evaluated and compared with the conventional protocol, which showed substantial reductions in lead times without compromising patient satisfaction. Number of patients treated in hours more than tripled, and the patient reception time per patient was shortened by approximately 20%. The main findings of the current series of studies should contribute to achieving better outcomes and preventing postoperative complications in cataract surgery. Rising burden of age-related diseases in ophthalmology adds to the challenge of providing high quality health services, and attention must be paid to the prevention and management of the most common complications.
  • Åström, Max (Helsingin yliopisto, 2021)
    Physical performance is an important predictor of both current and future health outcomes in older adults. As the proportion of adults over 65 years is expected to double by 2050, finding ways to prevent poor physical performance is important to promote independence and a good quality of life at older age. With an aging population, the prevalence of age-related chronic diseases, such as impairments in glucose regulation, is also expected to increase. The aim of this thesis was to investigate how age-related factors, including both impaired glucose regulation and telomere length, are associated with physical performance in older adults. In addition, the association between glucose regulation and pain was assessed. This thesis used data from the Helsinki Birth Cohort Study consisting of individuals born in 1934–1944 at the Helsinki University Central Hospital. Altogether 2003 individuals at a mean age of 62 years participated in a baseline clinical examination in 2001–2004, during which data on glucose regulation, grip strength, and pain were acquired. Approximately 10 years later, a total of 1094 individuals participated in a follow-up examination where physical performance was assessed using the Senior Fitness Test (SFT). Telomere length was assessed at both time points. An inverse linear association was observed between more severe disturbances in glucose regulation and the SFT score. Further, in cross- sectional analysis at baseline, those with either newly diagnosed or previously known diabetes had lower grip strength than individuals with normoglycemia. No difference in grip strength was observed between those with prediabetes and normoglycemia. Self-reported pain and use of pain medication were similar across all categories of glucose regulation. Finally, shorter telomere length at the follow-up examination and greater telomere attrition during the follow-up were associated with poorer physical performance in women. No similar associations were found in men. In older adults, a strong association between diabetes and poor physical performance was observed, including both grip strength and the more extensive SFT battery. Physical performance decreased linearly with more severe disturbances in glucose regulation, suggesting that a decline in physical performance may occur before the onset of diabetes. This indicates the importance of diagnosing and treating early stages of impaired glucose regulation in older adults. Although pain is a common symptom in adults, impairments in glucose regulation alone do not seem to increase the burden of pain. Telomere length may serve as a biomarker for physical performance at least in women, however, more longitudinal studies are needed to assess the usability of telomere length as a predictor of decreased physical performance.
  • Pajula, Susanna (Helsingin yliopisto, 2021)
    Background. After significant weight loss due to surgical or non-surgical methods, the skin and soft tissue around the body do not normalize or become as tight as it was before weight change. The excess redundant skin can cause functional, physical, and physiological challenges. Lower body contouring surgery (LBCS) is the only effective treatment to remove redundant skin after massive weight loss (MWL). Aims. LBCS was evaluated with respect to prevalence, outcomes, preceding muscle strength, and its effect on pregnancy and delivery in patients who had significant, redundant skin folds due to MWL. Main results. Altogether, 1089 (14.1%) of the 7703 bariatric patients underwent LBCS during 1998- 2016 in Finland. Abdominoplasty was the most common lower body contouring procedure (89%). The median latency between bariatric surgery (BS) and LBCS was 31 months. In research data, of the 1 028 503 total pregnancies and deliveries the study period, 92 women had had LBCS before pregnancy and delivery between 1999 and 2016.These 92 women had planned Caesarean sections more often (p <.001), and pre-term delivery (<37 weeks) was more common among them (p <.001). Subgroup analysis revealed that preceding bariatric procedures did not increase the risk for pre-term delivery or low birth weight. A total of 96 complications occurred in 80 of the 158 patients, with an overall complication rate of 51%. Most complications (80.2%) were minor No significant difference in complication rates existed between bariatric and non-bariatric patients. Older age (p=.042) at operation was associated with an increased risk for immediate haematoma or bleeding requiring surgery. Among early complications, a high maximum weight (p=.035) and a high pre-operative weight (p = 0.0053) significantly correlated with a haematoma or bleeding requiring surgery. For late complications, seroma correlated with older age (p =.0061) (Study III). Study IV subjects comprised 18 women and five men, with a mean age of 48.2 years and 36.2 years, respectively. In the hand grip test, 60% had poor muscle strength. Likewise, 70% reached only the lower level in dynamic muscle strength of the body. The lowest squats performed in the squat test were ten and the highest 30 in 30 seconds. Conclusions. The number of patients who undergo LBCS after bariatric surgery is relatively small in Finland. However, there is a strong correlation between bariatric surgery and two-year latency for LBCS. The second study revealed that pregnancies after LBCS most often proceed to term. However, the risk for pre-term delivery and a low-birth-weight baby is increased, especially after prior bariatric surgery. There is also an increased risk of cesarean section, although probably due to other confounding factors. Longer latency between the contouring operation and pregnancy does not decrease the risks. The complication rate after LBCS is relatively high, although most complications are primarily minor and non-life-threatening Patients with preceding MWL have lower muscle strength than the age- and gender-matched average population.
  • Backman, Heidi (Helsingin yliopisto, 2021)
    Psychopathy is a personality disorder characterized by affective, interpersonal, and behavioral antisocial features. The first signs can be detected early in life, when they are referred to psychopathic traits, developmental risks for psychopathy and callous-unemotional traits. A growing body of psychopathy literature is focusing on risk factors which may be genetic, neurobiological and environmental. The factors that promote positive outcomes are instead neglected The study project consists of Studies I–IV. The first publication was to investigate the role of psychopathic features in the associations between qualitative and quantitative aspects of sleep and delinquent behavior among Finnish adolescents. The second study examined how self-reported severe sleep problems related to scores on a self-reported psychopathy scale and its subfactors. The data were drawn from a Finnish Self-Report Delinquency Study with population-based sample of 4,855 Finnish adolescents (mean age 15.3 years, 51% females). Negative binomial regressions, analysis of variance, and multivariate analysis of variance were used. The results suggested that both sleep problems and an insufficient amount of sleep were associated with property crime and violent behavior, and that the relationship was not explained by gender, degree of parental supervision at bedtime or co-occurring psychopathic features. Adolescent self-reported severe sleep problems were associated with psychopathic traits. However, cause and effect cannot be distinguished. Studies III–IV examined the effects of interpersonal relationships and parental behaviors on adolescent psychopathic traits over time. Data were derived from repeated measurements of 1,354 offending adolescents (14.3% females; 40.1% black) in the Pathways to Desistance longitudinal study. Within-individual analysis showed that romantic and peer relationships of high quality were associated with lower psychopathic traits, whereas antisocial behavior and antisocial influence in interpersonal relationships were related to higher psychopathic traits. Further, those with no romantic relationships had lower mean levels of psychopathic traits than those in relationships of low quality. Further, maternal warmth associated negatively with psychopathic traits and offending among adolescent delinquents. Paternal warmth protected from psychopathic traits but not from delinquency, and both maternal and paternal hostility linked positively to psychopathic traits and offending. To conclude, sleep problems, social relationships, and parental influence should be taken into account in treatment and intervention programs targeted toward adolescents with psychopathic behaviors.
  • Pirneskoski, Jussi (Helsingin yliopisto, 2021)
    Appropriately assessing the physiological status of the patient in emergency care is essential to detect patients that would require urgent medical interventions. This requirement is highlighted in prehospital emergency medical services, which operate with limited diagnostic and therapeutic resources. Further knowledge on how to best detect physiological disturbances with simple measurements would allow personnel to recognise the patients at risk. This study aimed to establish the diagnostic accuracy and explore the factors affecting the accuracy of physiological scoring in prehospital emergency services settings. This study also investigated the feasibility of using photoplethysmography as an additional tool to recognise critically ill patients. This study was composed of four sub-studies, of which one was prospective and three were retrospective cohort studies. The study included 212 consecutive adult patients presenting to an emergency department (I) and 35 800 adult prehospital emergency medical services patients with sufficient data to calculate National Early Warning Score (NEWS) from 2008 to 2015. (II-III) A subgroup analysis was performed of the 26 458 prehospital patients that also had a blood glucose measurement performed (IV). Photoplethysmography variables were collected and compared between groups of critically and non-critically ill patients. (I) Diagnostic accuracy of NEWS in detecting mortality within 1, 7 and 30 days from emergency medical services contact was studied. (II) Effect of age on this predictive performance was compared in three different age groups and performance of NEWS modified to include age as an additional parameter was assessed. (III) Furthermore, a model based on logistic regression was compared to a random forest machine learning model in predicting mortality. (IV) Minimum and mean photoplethysmography amplitudes differed significantly between critically and non-critically ill patients. Diagnostic accuracy of photoplethysmography amplitudes for detecting critical illness had below moderate accuracy. Ability of NEWS values to predict mortality was best at the shortest studied time interval and in the youngest age group. Predictive performance worsened gradually when the time interval increased in all age groups. Ability to predict mortality was improved when age was added as an additional parameter to the logistic regression model. Random forest machine learning model was superior to logistic regression when NEWS parameters were used and improved even further when blood glucose value was included in the model. The most significant predictive physiological parameters were low oxygen saturation, high respiratory rate, and low systolic blood pressure. Heart rate had very low contribution to overall predictive performance. Lower photoplethysmography minimum and mean amplitudes can possibly be used in addition to other methods in the emergency department to differentiate critically ill patients, although the diagnostic accuracy is below moderate. NEWS can be used to predict mortality at 1, 7 and 30 days. Its predictive performance is best at one day from emergency medical services contact and in patients aged < 65 years when compared to longer time intervals and older age groups. This mortality prediction can be improved by adding age as an additional parameter. Random forest machine learning model using NEWS parameters outperforms a logistic regression model in predicting one day mortality of prehospital patients and can be further enhanced by including blood glucose value.
  • Salminen, Samuli (Helsingin yliopisto, 2021)
    Breast cancer (BC) is the most frequently diagnosed cancer and the leading cause of cancer death in women worldwide. The modern local treatment of early-stage BC is based on breast-conserving surgery and adjuvant radiotherapy (RT) combined with adjuvant medical treatments. RT increases the risk of radiation-associated sarcoma (RAS), which is a cancer of mesenchymal origin arising in the RT field after a varying latency. Particularly in BC patients, an increased risk of radiation-associated angiosarcoma of the breast (RAASB), a subtype of sarcoma emanating from the endothelial cells, has been observed. This study explored RAS and RAASB occurring in Finnish BC patients between 1953 and 2014. A search of the Finnish Cancer Registry yielded a total of 132,512 patients with an invasive BC, of whom 355 were diagnosed with a secondary sarcoma from 1953 to 2014. After a central expert histopathological review and medical record analysis, 96 patients were confirmed to have an RAS, of whom 50 patients (52%) were diagnosed with an RAASB. An increase in the incidence of RAASB was observed over the study interval. Eighty-two of 96 RAS patients (85%) had curative surgery; the five-year sarcoma-specific survival rate was 75%. The diagnostic aspects of RAASB were evaluated in a cohort of 58 patients; 50 were from the cancer registry search and eight patients were diagnosed at Helsinki University Hospital between 2015 and 2017. The sensitivity of mammogram and ultrasound in RAASB detection was low, while the performance of magnetic resonance imaging and computed tomography was comparatively high, although both modalities also produced several false negative results. Fine-needle aspirate cytology and core needle biopsy yielded consistently inaccurate results compared to punch biopsy, incisional/excisional biopsy, and surgical removal, all of which provided high sensitivity for RAASB detection. The treatment and prognosis of RAASB were investigated in a registry-based cohort of fifty RAASB patients. Forty-seven patients (94%) had curative surgery for RAASB, with a five-year overall survival of 74%. A greater planned lateral surgical margin of RAASB was associated with significantly better overall survival. The incidence of BC is expected to increase in the future, with a concomitant improvement in the overall prognosis. This emphasizes the importance of studying the severe adverse effects of BC therapy. The current study provides a unique perspective on RAS and RAASB after BC in Finland.
  • Ruohtula, Terhi (Helsingin yliopisto, 2021)
    Type 1 diabetes (T1D) and allergies are considered autoimmune diseases. The exact mechanisms leading to these diseases are mostly unknown, but genetic and environmental factors are involved. Regulatory T cells (Tregs) have a crucial role in initiating and maintaining tolerance, limiting harmful autoantigen-specific inflammation processes. This doctoral thesis explores the effect of environmental factors on the development of the immune system by studying peripheral immunological responses in healthy infants at genetic risk of T1D in two follow-up studies. The first study investigated the development of peripheral Treg cells in infants from Estonia and Finland, neighboring countries with differing living standards, and the incidence of T1D and allergies. We demonstrated a two-step maturation process in the circulating Treg cell population in the first two years of life. First, a decrease in the proportion of Treg cells followed by an increase in the highly activated Treg cells (TregFOXP3high), with enhanced suppressive activity. The Treg cell maturation process coincided with the microbiota composition development from a Bifidobacteria dominated to one dominated by butyrate-producing species by 36 months. The abundance of Bifidobacteria and the relative abundance of B.longum alone at three months showed an inverse association with atopic sensitization. The switch in the microbiota happened earlier in Estonia and was associated with more highly activated TregFOXP3high cells with FOXP3 and CTLA-4 expression. This earlier maturation of the circulating Treg population is associated with a lower risk of allergic diseases in Estonian children. Additionally, we analyzed the common enteral virus infections in the first year of life. We observed a temporal association of virus infection with the expression of FOXP3 in regulatory T cells. Infants with enterovirus infection during the preceding 30 or 60 days had a significantly decreased FOXP3 expression in TregFOXP3high cells. In addition, we observed upregulation of Th1- and Th17 -related cytokines and a decreased activation of CCL22, associating with activation of proinflammatory pathways and reduced immune regulation. In the second study, we examined whether exposure to bovine insulin is a trigger of autoimmunity by studying the appearance of diabetes autoantibodies. We studied exclusively breastfed infants or infants after exposure to different infant formulas; cow-milk formula (CMF) with bovine insulin, whey-based hydrolyzed formula, or a virtually bovine insulin-free whey-based hydrolyzed FINDIA formula during the first six months of life, whenever breast milk was not available. The follow-up was up to at least three years of age. We showed that weaning to the FINDIA formula reduced the incidence of autoantibody positivity when compared with CMF-formula. This result might reflect a dysfunctional immune system. Bovine insulin peptides from the infant formula may activate autoreactivity against the primary autoantigen, i.e., human insulin, resulting in non-tolerogenic T cells. To conclude, the study shows that environmental factors may influence regulatory T cells and immunotolerance. Also, nutrition may influence the development of the immune system or autoantibodies to T1D in infants genetically at risk. Keywords: type 1 diabetes, allergy, regulatory T cells, autoantibodies, viruses, diet
  • Lindström, Mikael (Helsingin yliopisto, 2021)
    Biomarkers are naturally occurring molecules that have different functions in the human body but can also be indicative of various clinical conditions. In the field of clinical chemistry, liquid chromatography mass spectrometry (LC-MS/MS) has quickly become the gold standard in measurement of many of these molecules. One of the key benefits of MS is excellent specificity and accuracy of detection. Mass spectrometry is exceptionally useful in studying small analytes in biological matrices, which makes it an essential tool in clinical and medical research and diagnostics. The aim of the study was to develop new LC-MS/MS assays to complement and improve existing methods, or to use mass spectrometry to measure recently recognized biomarkers in new ways. We developed and validated LC-MS/MS assays for three different clinical biomarkers, which included serum serotonin for diagnosis of neuroendocrine neoplasms (NEN), plasma bradykinin (BK) for monitoring septic shock progression and cerebrospinal fluid (CSF) orexin-A and -B for narcolepsy diagnostics. Many NENs are currently diagnosed by measuring serotonin metabolite 5-hydroxyindole acetic acid (5-HIAA) from either urine or serum, which is sensitive to dietary factors. Septic shock is a rapidly progressing life-threatening condition, for which medication exists, but it´s efficiency is highly dependent on the timing of the administration. We studied a potential sepsis biomarker BK by comparing samples from healthy volunteers to patients during different phases of the shock progression. Low CSF orexin-A is a currently agreed key diagnostic criterion for diagnosing narcolepsy, but the currently used radio immunoassay (RIA) may suffer from interferences and usually shows greater variability and imprecision between analysis batches than LC-MS/MS. The knowledge about the exact functions of a similar peptide orexin-B is still scarce, so this analyte was included in the assay as well. Of the developed assays, serum serotonin proved to be of equal performance compared to serum 5-HIAA assay and is a good complement for e.g. 5-HIAA in NEN diagnostics, both detecting NENs that the other had missed. BK was not found to be elevated during septic shock, and thus not a good biomarker to monitor sepsis, but the analytical method was sensitive and suitable for clinical research purposes. Orexin assay was successful in distinguishing narcoleptics from the healthy based on their CSF orexin-A concentration, but additional tests are needed to bring the assay to routine use due to the very limited sample quantities available to us during validation. Orexin-B concentrations in CSF samples were below our assay range. However, these results can be used as is, along with the few published LC-MS/MS assays for orexins, to determine the clinically relevant concentrations expected for both healthy and narcoleptic patients.
  • Simonsen, Johan Rasmus Alexander (Helsingin yliopisto, 2021)
    Background. Individuals with diabetes are more susceptible to bacterial infections compared with the general population. In individuals without diabetes, these infections have been associated with micro- and macrovascular diseases, such as chronic kidney disease and cardiovascular disease. However, the role of bacterial infections in the aetiology of these diseases is unclear, and may be profound in individuals with diabetes, who suffer from both bacterial infections as well as micro- and macrovascular disease more frequently compared to the general population. Furthermore, the prevalence of bacterial infections in individuals with specifically type 1 diabetes and the impact of hyperglycaemia on infection frequency is also far from established. Finally, the potential genetic factors affecting infection susceptibility in diabetes are yet to be discovered. Aim. The aim of this thesis was to investigate the frequency of bacterial infections in individuals with type 1 diabetes and how the infections associate with and potentially affect the risk of developing diabetic kidney disease, coronary heart disease, and diabetic retinopathy. Moreover, we investigated whether common variations in the genome were associated with the susceptibility to bacterial infections observed in diabetes. Methods. The studies presented in this thesis were conducted within the national multicentre study FinnDiane (Finnish Diabetic Nephropathy Study Group). The FinnDiane cohort consists of individuals with type 1 diabetes, recruited from all over Finland as well as non-diabetic control subjects from the general population. For all individuals included in the studies, data on bacterial infections treated both outside and within hospitals were collected from two nationwide registries: The national Finnish Hospital Discharge Register (Finnish Care Register for Health Care, HILMO) and the Finnish National Drug Prescription Register (KELA). Data on the emergence or progression of chronic diabetic complications as well as relevant clinical risk factors were collected during baseline and prospective clinical study visits, as well as from medical files collected from primary health care centres and hospitals across the country. Genomic DNA was extracted from blood leukocytes and bacterial lipopolysaccharide (LPS) activity was determined from serum samples during the baseline visit. Results. Bacterial infections were found to be roughly two times more common in individuals with type 1 diabetes, compared to non-diabetic control subjects. Infections were more frequent in individuals with diabetic kidney disease and/or poor glucose control. Frequent antibiotic purchases and high LPS-activity were found to be independent risk factors for incident coronary heart disease as well as severe diabetic retinopathy in type 1 diabetes. Genome-wide association studies (GWAS) on individuals with diabetes revealed a potential association between variants on chromosome 2 and a reduced infection susceptibility. This association between the genetic loci and infection frequency was possibly mediated through the regulation of the IRAK1-pathway. Conclusion. Bacterial infections are more frequent in individuals with type 1 diabetes than in the general population. Frequent antibiotic purchases and high levels of LPS-activity associate with the development of both micro- and macrovascular complications. Genetic factors on chromosome 2 may further influence the susceptibility to bacterial infections present in diabetes.