Lääketieteellinen tiedekunta

 

Recent Submissions

  • Jokinen, Ewa (Helsingin yliopisto, 2020)
    During recent decades, gynecological surgery has changed considerably, and this development affects surgical training. In Finland, the total number of gynecological procedures has decreased by 30% during the last ten years. An increasing number of basic procedures are now done under local anesthesia at outpatient clinics where training is much more demanding than in the operating room. Laparotomies are frequently replaced by laparoscopic procedures that require more complex skills than open surgery. Furthermore, operating room efficiency causes time constraints, while patients in general have more co-morbidities and the surgical procedures needed are more complex. Thus, for trainees all these factors make training more challenging, and the traditional apprenticeship model alone no longer ensures that trainees learn the needed skills. In this dissertation study our aim was to assess developments in gynecological surgery in Finland and other Nordic countries by evaluating trends in hysterectomies. In addition, we investigated outcomes of traditional surgical training, as compared to systematic cognitive and manual pre-training on laparoscopic skills. We assessed separately the effect of pretraining on the trainee’s first operative laparoscopy, and on the other hand, on laparoscopic hysterectomy, which is the most demanding laparoscopic procedure trainees perform. In Study I, we assessed the numbers of different hysterectomies from the Nordic Medico-Statistical Committee and Finnish Institute for Health and Welfare databases. We compared outcomes of different hysterectomy methods between trainees and specialists collected from the FINHYST 2006 survey. In Finland, hysterectomy rates started to decline in 2003 and reached the rate of other Nordic countries in 2008. The rate of hysterectomy in Finland declined until 2017, and the laparoscopic method has been the most common method since 2013. In the outcome comparison, it was noted that the overall operative time was longer in trainees’ operations. In the vaginal method, blood loss was higher in the trainees’ group whereas in other hysterectomy methods or in total complication rates there were no differences between the groups. In Study II, we evaluated the effectiveness of a cognitive web-course ‘Basics in Gynecological Laparoscopy’ for trainees at various levels of experience. All trainees in Finland were invited to participate in this web-based anonymous study where the level of knowledge was evaluated before and after taking the course. Participants were allocated into three groups according to their experience. After the course, improvement in knowledge gain was detected in all three groups; the less experienced group reached the starting level of the middle group and the middle group reached the starting level of the most experienced group. In Studies III and IV, the effect of simulator training on operative skills was evaluated. Trainees with no experience in operative laparoscopy were recruited for Study III. Half of the group comprised the intervention group. They did the web-based course ‘Basics in Gynecological Laparoscopy’ and trained basic skills with a virtual reality simulator. The control group took part in the traditional training only. The first live laparoscopic salpingectomy was video-recorded and evaluated. We found no differences in the surgical outcomes between the groups. In Study IV, the participants recruited were more experienced, but had not done laparoscopic hysterectomy as a first surgeon. All participants did the basic training as the intervention group in Study III. Furthermore, the intervention group trained with the hysterectomy module in a virtual reality simulator. The intervention group performed significantly better as evaluated by the Objective Assessment of Technical Skills and Visual Analog scale. Our findings indicate that the traditional apprentice model alone is no longer sufficient in trainee education due to changes in gynecological surgery. In Study III, we did not detect differences in outcomes between the groups. However, in Study IV evaluating learning of a more advanced procedure, we demonstrated better performance after training with the procedural module in a simulator. Based on these studies, we suggest that simulator training should be mandatory, with allocated training time for the trainee and supervision time for the trainer for providing feedback. As innate skills are different, a proficiency-based curriculum results in more homogeneous skills. Less experienced trainees seem to benefit the most from simulator training, thus the training should be started in the earliest stage of training.
  • Lindblad, Ritva (Helsingin yliopisto, 2020)
    Dental caries or trauma may cause loss of coronal material so that endodontic treatment is needed. The aim is then to avoid or eliminate the infection, to replace the lost tissue and to restore the function and esthetics of the dentition. A tight and durable interface between the material in root canal and root dentin is crucial to inhibit the bacterial reinfection and to assure the longevity of the restauration. The bond strength of composite resin restoration on coronal dentin decrease with time. Previous studies have shown that chlorhexidine (CHX) and dimethyl sulfoxide (DMSO) preserve the long term bond strength between the restauration and coronal dentin. They both act as matrix metalloproteinase (MMP) -enzyme inhibitors which may be one reason to the bond strength preserving ability. DMSO has also the ability to reduce dentin surface free energy, improve wettability (slightly also CHX) and by that to enhance the adhesive penetration. This series of studies investigated the effect of CHX and DMSO on the immediate and long term bond strength of chemically different resin cements, sealers and calcium silicate cements (CSCs). If the bond strength of resin cements, sealers and CSCs could be improved and preserved by using MMP inhibitors, it would have a great importance to the restorative dentistry. By improving the adhesion the risk of bacterial penetration in the bonding interface decreases, the longevity of the root filling and restoration with root canal post is improved, the fracture risk of teeth restored with fiber posts decreases, and the need for retreatment is also decreased. As conclusion 2% CHX may at least moderately improve the long-term post adhesion, but the effect may be material dependent. On the other hand 2% CHX may negatively affect the bond strength and the failure rate of both CSCs. DMSO as a final irrigant resulted with the lowest long-term leakage with both sealers and CSCs, indicating that probably the superior wettability induced by DMSO contributes to this interface integrity. Although the amount of leakage in these studies was very small, it cannot assume that these obturations would have totally inhibited the bacterial invasion with time.
  • Seikku, Laura (Helsingin yliopisto, 2020)
    Fetal life occurs in a relatively hypoxic environment. During normal pregnancy, several compensatory mechanisms secure fetal oxygenation and wellbeing. In complicated pregnancies, however, intrauterine hypoxia predisposes the fetus to growth restriction, stillbirth, neurodevelopmental sequelae such as cognitive dysfunction and cerebral palsy (CP), and adverse long-term health impacts. Impairment of respiratory gas exchange—during either pregnancy or delivery—leads to tissue hypoxia, and, if prolonged, to metabolic acidosis and asphyxia. Worldwide, such asphyxia, diagnosed at birth, annually accounts for a million neonatal deaths. Furthermore, neonatal hypoxic ischemic encephalopathy (HIE) originating from perinatal asphyxia may lead to a variety of neurodevelopmental impairments. Therapeutic neuroprotective interventions such as hypothermia have significantly improved the prognosis of severe neonatal encephalopathy. Increased risk for intrauterine fetal hypoxia and perinatal asphyxia occur in various circumstances and pregnancy complications—such as intrauterine growth restriction (IUGR), which affects up to 10% of pregnancies. Timing the delivery in preterm pregnancy with severe IUGR is challenging, owing to balancing between risks related to prematurity and to fetal hypoxia. Another obstetric challenge concerns timing of delivery as well: Neonatal outcomes vary by gestational age also among term pregnancies. In pregnancies beyond 41 gestational weeks, the risk for perinatal morbidity and mortality increases, probably due to the relative insufficiency of the aging placenta. Numerous methods such as fetal Doppler assessments and computerized cardiotocography help in monitoring placental function and fetal wellbeing. These methods, however, are not unequivocally efficient in predicting adverse neonatal outcomes in IUGR or in prolonged pregnancies. Furthermore, the time window for neuroprotective treatment in birth asphyxia is narrow, and additional methods for identifying those neonates who would benefit from neuroprotective actions are essential. We thus searched for biomarkers identifying those fetuses at risk for hypoxia-caused complications, and for predicting outcome after birth asphyxia. Erythropoietin (EPO) is a biomarker of chronic hypoxia, with high levels of EPO associating with increased risk for adverse outcome. S100B is a biomarker of brain- cell damage, and its levels rise in early phases of acute asphyxia. Copeptin, a by-product of arginine vasopressin (AVP) production, is a potential biomarker of birth asphyxia and HIE. Additionally, we aimed to evaluate the association of gestational age with perinatal asphyctic complications and long-term neurologic morbidity. The biomarker studies (I-III) were conducted in the University Hospital of Helsinki, Finland. Data on maternal pregnancy and delivery characteristics, and short-term neonatal outcomes such as Apgar score, originated from hospital charts. The study populations comprised 66 pregnancies complicated by preterm IUGR, 93 low-risk term and prolonged pregnancies, and 140 term neonates with birth asphyxia. Amniotic fluid samples for EPO evaluations we obtained by amniocentesis, at cesarean section, or vaginally at amniotomy. Umbilical serum plasma samples for EPO, copeptin, and S100B assessments we collected at birth. Biomarker levels in amniotic fluid and umbilical plasma samples we measured by immunoassays. Normal amniotic fluid EPO levels we defined as < 3 IU/L, with abnormal levels exceeding 27 IU/L. We considered as normal umbilical plasma EPO levels below 40 IU/L. The register-based cohort study on asphyxia and neurologic morbidity (IV) comprised 1 138 109 women with singleton pregnancies and their newborns between 1989 and 2008 in Finland. The Finnish Medical Birth Register (MBR), maintained by the National Institute for Health and Welfare (THL), provided data for this study. Statistical analyses we performed with the Statistical Package for Social Sciences (SPSS, Chicago, IL, USA), GraphPad Prism 6 and SAS version 9.3 (SAS Institute, Inc, Cary, NC, USA). All tests were two-sided, with probability (p) values of < 0.05 as statistically significant. In IUGR pregnancies, abnormal amniotic fluid EPO levels were associated with decreased umbilical artery pH and base excess (BE) values, abnormal biophysical profile, and reversed end-diastolic flow in the umbilical artery. Most importantly, such abnormal EPO levels were associated with composite adverse neonatal outcomes defined as intraventricular hemorrhage, periventricular leukomalacia, cerebral infarction, or necrotizing enterocolitis (p < 0.001). In low-risk term and postterm pregnancies, EPO levels in amniotic fluid and in umbilical serum correlated with gestational age. Furthermore, EPO levels in amniotic fluid correlated with the levels in umbilical serum, even after vaginal delivery. Among low-risk pregnancies, however, EPO levels correlated with neither umbilical artery pH or BE, nor with other adverse pregnancy outcomes. In our study on biomarkers in birth asphyxia, only copeptin correlated with arterial pH. Its correlation with umbilical artery BE was significantly stronger than were the correlations of S100B or of EPO. Copeptin levels, significantly higher among neonates with birth asphyxia, we demonstrated to increase as a function of labor duration. In the cohort study, multivariate analysis demonstrated an increased risk for low (< 4) one- and five-minute Apgar score, CP, intellectual disability, sensorineural defects, and perinatal mortality among early-term births. Postterm birth resulted in increased risk for low one- and five-minute Apgar scores (< 4), low umbilical artery pH ≤ 7.10, and intellectual disability, whereas risks for CP, epilepsy, sensorineural defects, and perinatal mortality showed no increase. In conclusion, among preterm IUGR pregnancies, high amniotic fluid EPO levels were associated with decreased umbilical artery pH and BE, and with adverse neonatal outcomes. In selected risk-pregnancies, determining amniotic fluid EPO may thus be a useful additional tool in fetal surveillance and in optimizing delivery timing. In term pregnancies, EPO levels correlated with gestational age, probably explained by advancing gestation resulting in weakening placental function and relative hypoxemia. Among low-risk populations, however, EPO was not related to adverse delivery outcomes, and thus may not prove clinically useful in such populations. Furthermore, in cases of acute birth asphyxia, S100B and EPO as biomarkers may not prove valid. In contrast, copeptin has potential for routine use as a biomarker for acute birth asphyxia and neonatal distress. Future studies should determine the correlation of biomarker levels at birth with severity of HIE and with long-term neurological outcome following birth asphyxia. Concerning gestational age at birth, we found an increased risk for low Apgar score, increased neurologic morbidity, and perinatal mortality among early-term neonates. Among postterm births, the risk for birth asphyxia was increased. The long-term neurologic health impacts of postterm birth, however, were less important than previously expected, meaning that further studies on the optimal management of pregnancies beyond 41 gestational weeks are essential.
  • Lantto, Hanna (Helsingin yliopisto, 2020)
    Approximately 80 % of women reaching menopause experience vasomotor hot flashes that are often accompanied with palpitation symptoms. Hot flashes are also a common reason to consult a physician for postmenopausal hormone therapy. The exact mechanism of hot flashes is unclear, but they are related to alterations in autonomic balance. The autonomic nervous system is a major regulator for cardiac function and rhythm, and increased sympathetic and decreased parasympathetic activity are associated with increased cardiovascular risk and potentially life-threatening arrhythmias. Therefore, hot flashes may modify the cardiovascular risk profile in postmenopausal women. The aim of this study was to investigate the association of hot flashes and postmenopausal hormone therapy on cardiac autonomic reactivity and risk profile. The study included 150 healthy, recently postmenopausal women with varying degrees of severity of hot flashes. The study population was randomized to receive transdermal estradiol gel, oral estradiol alone or combined with medroxyprogesterone acetate, or placebo. Cardiac autonomic reactivity and risk profile were assessed with heart rate variability and ventricular repolarization measures from 24-hour electrocardiographic recording at baseline and after 6 months of treatment. Women with hot flashes did not have clinically significant differences in cardiac cardiovascular risk markers based on ambulatory heart rate variability and cardiac repolarization measures, compared with women without hot flashes. However, hot flash periods were accompanied with transient changes in heart rate variability, indicating increased sympathetic and decreased parasympathetic tone during hot flash. Sympathetic surge during the hot flash period may also acutely and directly modulate cardiac repolarization. During postmenopausal hormone therapy, transdermal estradiol showed neutral effects on cardiac rhythm. Oral estradiol combined with medroxyprogesterone acetate may have adverse effects on heart rate variability, regardless of the hot flash status. Additionally, oral estradiol combined with medroxyprogesterone acetate may be related to more frequent cardiac arrhythmias than estradiol only. Hot flashes may predict a beneficial effect on cardiac repolarization during oral estradiol treatment, but not if medroxyprogesterone acetate is combined with the treatment.
  • Dumont, Vincent (Helsingin yliopisto, 2020)
    Background. Diabetes mellitus is a metabolic disease characterised by the inability of the body to maintain stable glycaemia. Diabetic kidney disease (DKD), the renal complication of diabetes, is the leading cause of end-stage renal disease in Europe and in the USA. Approximately 40% of individuals with diabetes develop this microvascular complication that may eventually require dialysis or kidney transplant. DKD is characterised by progressive loss of the permselectivity of the glomerular filtration barrier and declining glomerular filtration rate. The pathological mechanisms of DKD are not fully elucidated but podocyte injury is involved. In particular, alterations in the expression or localisation of nephrin, changes in the regulation of the actin cytoskeleton organisation and defects in the insulin signalling pathway are involved. This work characterises the renal phenotype of a novel transgenic mouse model of hyperglycaemia triggered by hypoinsulinaemia due to the defective β-cell mass growth in the pancreas. It also aims to evaluate the expression, the role and the phosphorylation status of protein kinase C and casein kinase 2 substrate in neurons (PACSIN2) in the trafficking of nephrin and the regulation of the actin cytoskeleton organisation in the context of DKD in podocytes. Further, the thesis refines how septin 7 hinders the trafficking of glucose transporter 4 (GLUT4) storage vesicles, as septin 7 was recently found to inhibit glucose uptake in podocytes. Results. The characterisation of hyperglycaemic E1-DN mice revealed in homozygous mice an increased urine volume as well as albuminuria, the severity of which correlated with the hyperglycaemia. The kidneys developed changes typical of human DKD, such as tubular proliferation and atrophy, mesangial expansion and glomerular basement membrane thickening, lower expression of nephrin, foot process effacement and podocyte apoptosis. Next, we found that PACSIN2 expression was elevated in the glomeruli of obese Zucker Diabetic Fatty (ZDF) rats, a model of advanced DKD. Interestingly, the obese ZDF rats had albuminuria and altered localisation of nephrin. We found that overexpression of PACSIN2 increased both endocytosis and recycling of nephrin. This may rely on the newly identified PACSIN2-nephrin-rabenosyn-5 protein complex. Interestingly, the interaction of PACSIN2 with nephrin was stimulated by treating podocytes with palmitate, the most abundant free fatty acid (FFA) in the circulation and elevated in diabetes. Our data using isolated glomeruli from ZDF rats and human, as well as using cultured podocytes treated with sera from diabetic patients with normal kidney function or microalbuminuria suggested that PACSIN2 phosphorylation at serine 313 is increased in the context of DKD but not diabetes alone. We identified that palmitate induced the phosphorylation of PACSIN2 at S313 in a protein kinase C-dependent manner. Finally, we found that overexpression of PACSIN2 altered the actin cytoskeleton organisation and morphology of podocytes in culture, and that constitutively phosphorylated PACSIN2 at S313 showed milder effect. In the work concentrating on the trafficking of GLUT4 in podocytes, we found that septin 7 forms a complex with nephrin and nonmuscle myosin IIA (NMIIA) at the plasma membrane in the docking and fusion site of GLUT4 storage vesicles (GSVs). We showed that removal of septin 7 and activation of NMIIA in the docking and fusion site are essential for insulin-stimulated glucose uptake. Also, the presence of septin 7 and the activity of NMIIA at the docking and fusion site appeared to be regulated by circulating factors in the serum of individuals with type 1 diabetes and macroalbuminuria. Conclusion. In this thesis, we identified that PACSIN2, the expression of which is increased in podocytes in DKD, regulates the localisation of nephrin in cultured podocytes. In vitro, PACSIN2 also regulates the actin cytoskeleton organisation depending on its phosphorylation at S313, also elevated in DKD. We found that septin 7, together with NMIIA, regulates the docking and fusion of GSVs with the plasma membrane in podocytes. Thus, we propose that PACSIN2, septin 7 and NMIIA are central molecules in podocytes, and participate in the progression towards DKD by regulating the organisation of the actin cytoskeleton and the trafficking of nephrin and GLUT4.
  • Bugai, Andrii (Helsingin yliopisto, 2020)
    DNA damage response (DDR) is a cascade of events within the cells, which is initiated by DNA lesions and results in DNA repair and cell survival. Alternatively, DDR could lead to apoptosis - elimination of cells, in which genetic integrity is impossible to restore. Despite the commonly accepted paradigm that RNA synthesis is shut down following DNA damage, recent studies suggest that transcription of DDR genes is activated. The aim of my dissertation is to shed new light on the molecular mechanisms of the transcriptional response to DNA damage. Gene transcription is the process of transfer of genetic information from DNA to RNA. There are three major steps of transcription: initiation, elongation, and termination. Pausing in early elongation is a key control point of RNA polymerase II (Pol II)-mediated transcription. Negative transcription elongation factors (N-TEFs) interact with Pol II to mediate promoter-proximal pausing. Cyclin-dependent kinase 9 (CDK9) of the positive transcription elongation factor b (P-TEFb) phosphorylates N-TEFs and the C-terminal domain (CTD) of Pol II to resume transcription of paused genes. Small nuclear ribonucleoprotein complex containing 7SK RNA (7SK snRNP) regulates P-TEFb, offering a possibility for the rapid transcription of DDR genes following genotoxic stress. Here I provided new insight into the molecular mechanism of the transcriptional response to DNA damage. Using high-throughput protein-RNA interactome mapping by UV crosslinking and immunoprecipitation (iCLIP), nascent RNA sequencing, quantitative PCR, and RNA interference experiments I showed that, following genotoxic stress, RNA-binding motif protein 7 (RBM7) stimulated Pol II pause release by activating the P-TEFb via its release from the inhibitory 7SK snRNP. This was mediated by activation of p38 MAPK, which triggered enhanced binding of RBM7 with core subunits of 7SK snRNP. In turn, P-TEFb relocated to chromatin to induce transcription of short units, including key DDR genes and multiple classes of non-coding RNAs (ncRNA). Inhibition of the CDK9 subunit of P-TEFb or depletion of RBM7 provoked cellular hypersensitivity to DNA-damage-inducing agents via activation of apoptosis. In sum, my work suggests that RBM7 controls transcriptional response to DNA damage through P-TEFb. Moreover, it uncovers the importance of stress-dependent stimulation of the Pol II pause release, which enables a pro-survival transcriptional response that is crucial for cell fate upon genotoxic insult.
  • Björkqvist, Johan (Helsingin yliopisto, 2020)
    Background. Premature birth can be a harsh start to life; globally it is the leading cause of death in children under five and the outlook is grimmer the smaller the child. This perilous beginning is not the only adversity these survivors face, however. Decades-long follow-up studies have revealed subtle impairments in many domains of mental and physical health, intellectual achievement, and wellbeing, especially in survivors born preterm (<37 weeks gestation) with a very low birth weight (VLBW, <1500 g). These studies have described many long-term outcomes in detail, but other important subjects, such as sleep and chronotype have received far less attention. Chronotype is the personal preference for the timing of activity and sleep; it is a behavioural manifestation of the internal circadian clock, and people with very early or late preferences are sometimes called morning larks and night owls. Chronotype, sleep duration, and sleep quality are all important and independent predictors of health and wellbeing, and interestingly, studies have shown that late chronotype and poor sleep are associated with similar adversities as prematurity, such as poorer mental and cardiometabolic health. This raises the question if late chronotype, poor sleep, and prematurity are associated. Novel studies of prematurity-related morbidity expand our knowledge of the phenomenon, but some fundamental questions also require regular revisiting, such as: do survivors of early modern neonatal care have poorer quality of life? Aim. This thesis investigated if preterm birth and VLBW are associated with adult chronotype, sleep duration, sleep quality, or health-related quality of life (HRQoL). Methods. This thesis investigated adult preterm subjects and term-born controls from four different but in part overlapping studies and birth cohorts: The preterm subjects of The Helsinki Study of VLBW Adults (HeSVA) received treatment in the neonatal intensive care unit (NICU) of the Children’s Hospital in 1978-85. The subjects of the ESTER Preterm Birth Study came from the Northern Finland Birth Cohort 1986, and a cohort of subjects born 1987–89 in the same area, identified via the Finnish Medical Birth Register (FMBR). The Arvo Ylppö Longitudinal Study (AYLS) is part of a multicentre follow-up study of subjects admitted to neonatal wards or the Children’s Hospital NICU in 1985-86. The preterm subjects of ESTER and AYLS are from the whole gestation range, classified as early preterm (<34 weeks) and late preterm (34 to <37 weeks). The Sibling Study consists of VLBW adults and their term-born siblings. The preterm subjects consisted of previous participants from the HeSVA (1978-85) and ESTER (1987-89) studies, and new recruits identified via the FMBR, born in 1987-90 in the University Hospitals of Turku or Tampere, or in the hospital district of Helsinki-Uusimaa. This thesis used wrist-worn accelerometers called actigraphs to objectively measure sleep timing, duration, and quality. The main measure for chronotype was sleep midpoint on free days corrected for sleep debt, MSFsc. Further, this thesis utilized the Morningness-Eveningness Questionnaire to investigate subjective chronotype, and the 15D instrument to provide information about HRQoL. Results. Study I compared actigraphy data of 40 VLBW young adults and 35 controls in the HeSVA cohort at a mean age of 25.0 years (SD 2.2). It discovered that preterm participants displayed a significantly earlier corrected sleep midpoint (65 min, 95% CI 14 to 116 min, p = 0.013) than term-born controls. No difference in sleep duration or quality emerged. Study II compared actigraphy data of 63 VLBW subjects and 60 term-born siblings (53 complete pairs) at a mean age of 29.8 years (SD 4.1). The corrected sleep midpoint was again earlier in the VLBW group (46 min, 95% CI 16 to 77 min, p = 0.004), and again neither sleep duration nor quality differed meaningfully. Study III compared actigraphy data of 83 early and 165 late preterm subjects to 346 term-born controls in the pooled ESTER-AYLS cohort (mean age 24.3, SD 1.3). No difference in corrected sleep midpoint, sleep duration, or sleep quality emerged. Further, the Morningness-Eveningness Questionnaire was completed by 138 early preterm, 221 late preterm, and 329 control subjects in the ESTER study: neither the distribution of chronotype nor the Morningness-Eveningness Score differed between groups. Study IV compared the health-related quality of life of 164 VLBW and 172 control subjects in the HeSVA cohort at a mean age of 22.5 years (SD 2.1). Overall the preterm group reported similar HRQoL to controls, but subgroup analysis revealed differences. VLBW adults born small for gestational age (SGA) reported worse HRQoL (0.911 versus 0.939, p = 0.039) than VLBW adults born appropriate for gestational age (AGA), possibly because AGA-VLBW men scored well, whereas VLBW women born SGA scored worse HRQoL. Conclusion. Contrary to expectations, preterm subjects displayed an earlier chronotype rather than later. This finding was limited to those born smallest; comparison of less preterm groups to controls did not discover any discernible differences. Sleep duration and quality do not seem to differ from controls, nor does the health-related quality of life in general, even if subgroups showed clear differences. These studies suggest the possibility of an early programming of chronotype and they elaborate the spectrum of influences that impact long-term outcomes of premature birth. Keywords: VLBW, preterm, chronotype, actigraphy, MEQ, sleep midpoint, MSFsc, HRQoL, 15D instrument
  • Rebane, Katariina (Helsingin yliopisto, 2020)
    Juvenile idiopathic arthritis (JIA) is a disease that begins in childhood, but has influences over adulthood. Aim of the current study was to find out associations between pain and different health-related or psychosocial factors and the influences of pain to the children and their families, and to young adults with JIA. In addition, the use of analgesics was studied in early state of the JIA: a year before and after antirheumatic medication was started. In this study, we did not find significant correlation between the active joint count and pain in children with JIA, but somatic complaints, depressive symptoms, anxiety, lower functional disability and social self-efficacy and parental depressive symptoms were related to child’s pain. Child’s depressive symptoms, somatic self-efficacy, as well as parental and child perceptions of the child’s functional capability were independently predicting child’s pain. Among the young adults with JIA, a group of socially restricted patients was distinguished. Socially restricted patients had lower educational level, lower self-esteem, poorer health-related quality of life, they participated less in leisure-time non-physical activities, and had lower functional ability. We found that pain intensity was related to pain interference. Greater pain interference was associated with higher disability, having higher pain-related anxiety, and having lower physical activity and less hobbies during leisure time. Purchases of analgesics in newly diagnosed JIA patients increased during 12 months before and decreased sharply after disease modifying antirheumatic drugs were started, although remained higher compared to their matched controls. In its entirety, children and young adults with JIA are coping well. More attention should be paid to parental and children’s psychological well-being and their ability to manage with chronic disease. Later, during young adulthood, JIA patients are at risk to become socially restricted. Therefore focusing not only on disease activity, but also on patients’ education, participation in everyday life and quality of life should be started already in childhood to avoid further consequences. We provided novel information about pain interference and social participation in young adults with JIA and about the use of analgesics in children with JIA.
  • Linderborg, Klas (Helsingin yliopisto, 2020)
    Background There is clear evidence that alcohol consumption is a risk factor for several cancers in humans. Ethanol is not carcinogenic as a molecule, but there is conclusive evidence that acetaldehyde, formed by microbial metabolism of ethanol in the upper digestive tract, acts there as a local carcinogen. Acetaldehyde is found in varying concentrations in alcoholic beverages and also in foods. This acetaldehyde could contribute to overall acetaldehyde exposure in the upper digestive tract. Consumption of calvados has been linked to an increased risk for oesophageal cancer in France. Achlorhydric gastritis is a premalignant condition, in which gastric bacterial overgrowth can lead to increased acetaldehyde concentrations in the stomach after ethanol ingestion. L-Cysteine binds to acetaldehyde and can be used to lower acetaldehyde concentrations possibly reducing acetaldehyde exposure, and the carcinogenic effects thereof. Aims The first and second aim of this thesis was to examine acetaldehyde concentrations in calvados and other alcoholic beverages, and to study the exposure to acetaldehyde after a sip of these beverages. The third aim was to develop and test a slow-release L-cysteine formulation for eliminating carcinogenic acetaldehyde in achlorhydric stomach during ethanol exposure. Methods Firstly, farm-made calvados was collected in Normandy, France. Ethanol and acetaldehyde concentrations were measured and compared to samples of commercially available alcoholic beverages. Secondly, salivary acetaldehyde concentrations were measured after small sips of alcoholic beverages. Calvados with high acetaldehyde concentration was compared to ethanol of similar concentration without acetaldehyde. Thirdly slow-release L-cysteine capsules were formulated and given to volunteers with achlorhydric gastritis prior to infusion of dilute ethanol through nasogastric intubation. Samples of gastric juice were subsequently aspirated and analysed for acetaldehyde and L-cysteine concentration. Results and conclusions We found 42% higher mean acetaldehyde concentrations in farm-made and industrially manufactured calvados when compared to other alcoholic beverages. Markedly elevated concentrations of acetaldehyde were found to be produced from ethanol in the oral cavity instantly after a small sip of alcoholic beverage, and that the exposure continued for at least 10 minutes. Acetaldehyde present in the beverage had a small, short-term increasing effect on total acetaldehyde exposure. Furthermore, we found that L-cysteine can be used to decrease acetaldehyde concentration to less than half in gastric juice after ethanol ingestion in test subjects with achlorhydric gastritis. Acetaldehyde produced microbially from ingested ethanol is probably the main source for carcinogenicity of ethanol in upper digestive tract, although acetaldehyde in beverages contributes slightly to overall acetaldehyde exposure. This could explain the increased risk for oesophageal cancer associated with consumption of hot calvados. Slow-release L-cysteine capsules can be used to reduce acetaldehyde exposure in achlorhydric stomach during ethanol consumption.
  • Liimatainen, Hanna (Helsingin yliopisto, 2020)
    In this thesis, the role of genetic variation of human JC and BK polyomaviruses (JCPyV, BKPyV) in the development of severe polyomavirus-associated diseases was investigated by characterizing JCPyV and BKPyV strains present in urine, plasma, and cerebrospinal fluid samples using next-generation sequencing. These viruses are established human pathogens causing clinical manifestations almost exclusively in immunosuppressed patients. Immunosuppression allows lytic JCPyV infection in the brain, which is a hallmark of severe brain disease, progressive multifocal leukoencephalopathy (PML). Lytic BKPyV infection in the kidneys may result in the development of BKPyV-associated nephropathy (BKPVAN). Rare cases of nephropathy associated with JCPyV (JCPVAN) have been reported as well. No treatment is currently available leaving reduction of immunosuppression as the only therapy option. Mutations within the viral genome affect pathogenicity of JCPyV, and the same has been suggested for BKPyV. Although PML is always associated with mutated neurotropic JCPyV strains, the exact content of mutations, as well as where, when, and how neurotropic strains develop is unknown. Mutations are frequently seen in BKPVAN-associated BKPyV strains as well, but their association with the pathogenesis of BKPVAN remains elusive. First, we performed single-molecule real-time sequencing of complete JCPyV genomes from three PML patients and characterized all mutations within the viral regulatory region and the major capsid protein of each individual virus strain. We identified three distinct neurotropic JCPyV strains from cerebrospinal fluid of one PML patient. Mutations in the viral regulatory region and in the major capsid protein gene seem necessary for PML pathogenesis. Moreover, the presence of an archetype-like strain in one patient indicates that even minor mutations may be sufficient for the development of PML. Second, we were the first to show the predominance of archetype JCPyV in the urine of twenty stable kidney transplant patients and one patient with extremely rare JCPVAN. Contrary to PML, mutations within the JCPyV genome seem not necessary for the development of JCPVAN, but rather patient-specific factors, such as cell-mediated immunity, may play a role in the pathogenesis of JCPVAN. In the third and fourth studies, we characterized BKPyV regulatory regions from the plasma and urine samples of kidney transplant patients with or without histologically confirmed BKPVAN. Archetype BKPyV predominated in all but one patient but also very small populations of mutated BKPyV strains were detected. Interestingly, viral microRNA expression, as measured in the plasma of nine presumptive and biopsy-confirmed BKPVAN patients, was increased in the presence of mutated strains. Similar to JCPVAN, archetype strains may be sufficient for the development of BKPVAN, but even low amounts of mutated strains may affect pathogenicity of BKPyV by regulating the expression of viral microRNAs. This thesis contributes to the understanding of the role of genetic variation of JCPyV and BKPyV in the pathogenesis of PML, JCPVAN, and BKPVAN. Viral mutations seem necessary for the development of PML in the brain, but not for BKPVAN and JCPVAN in the kidney where other factors may play a role. The results help improving the diagnostic methods for the prognosis and prevention of these severe diseases.
  • Andersson, Saana (Helsingin yliopisto, 2020)
    In 2016, 1742 men and 992 women were diagnosed with lung cancer in Finland (Finnish Cancer Registry, 2016). The 5-year survival of LC ranges from 8% to 20%. The aims of this study were to 1) evaluate surgical results and very long-term quality of life in patients operated on for central non-small cell lung cancer (NSCLC) using either pneumonectomy (PN) or sleeve lobectomy (SL); 2) examine whether the location of lymph-node positive NSCLC in mediastinum or hilum influences the survival of these patients, 3) the impact of video-assisted thoracic surgery (VATS) on very long-term health-related quality of life (HRQoL) and 4) investigate the learning curve of an experienced VATS surgeon when institutional robotic-assisted lobectomy was programmed. Study I included 641 NSCLC patients operated between 2000 to 2010. 67 had PN and 40 patients had SL. In 2011, all surviving patients were sent a 15D Quality-of-Life questionnaire. Propensity-score-matching analysis was utilized to compare the groups and overall 5-year survival, distant and locoregional recurrence pattern, and very-long term quality of life. In study II, we reviewed data of 881 operated NSCLC patients with R0 resection combined with mediastinal lymphadenectomy. Patients with unsuspected positive lymph node metastasis in hilar (N10) or mediastinal (N2) were analyzed. In study III, we evaluated 456 patients who underwent lobectomy for the treatment of NSCLC in VATS or conventional thoracotomy between 2006 and 2013. 199 patients were mailed the generic HRQoL instrument 15D. Very-long term quality of life was analyzed. For study IV, a retrospective comparison of a single surgeon that performed the first 75 VATS lobectomies between 2007 to 2012 and 75 robotic-assisted (RATS) lobectomies between 2011 to 2018. The data from the initial cases were evaluated and a cumulative sum (CUSUM) analysis was applied to the duration of the operations. In Study I, the 5-year survival, rate of distant metastasis or locoregional recurrence did not differ between groups. Very long-term quality of life measured by 15D did not reveal significant differences in separate dimensions or total score. In Study II, PFS was statistically significant better in superior mediastinal and aortic nodes versus inferior mediastinal nodes. The overall survival (OS) of positive hilar Naruke 10 did not differ from that of inferior mediastinal nodes. In Study III, patients that had lobectomy performed by VATS had significantly lower very-long term quality of life in the dimensions of breathing, speaking, usual activities, mental function, and vitality. In Study IV, the operative outcomes were similar between RATS and VATS groups. The analysis of the surgeon learning curves for VATS and RATS based on operative time reached proficiency at 53 VATS and 45 RATS. Sleeve operations have fewer major operative complications. PN should be considered in suitable patients if SL does not seem to be oncologically sufficiently radical. Inferior positive mediastinal N2 node patients seem to have OS and PFS as poor as multilevel N2 patients. The OS and PFS of patients with positive hilar disease are similar to those in the inferior mediastinal positive N2 group. Very long-term quality-of-life measures are poorer among patients who were treated with VATS compared to thoracotomy patients. In the treatment of local NSCLC, the perioperative results of RATS and VATS lobectomies of the same surgeon were equally good. Even if the surgeon is experienced, a long learning curve for robotic surgery implementation is required.
  • Schmotz, Constanze (Helsingin yliopisto, 2019)
    Around 30 years ago, the discovery of modular protein domains began to change the scientific world’s view on cell signalling. The multitude of ground-breaking discoveries in this field over the past three decades increased fundamentally the understanding of cellular signal transduction and how proteins transmit extra- and intracellular signals in this context. The SH3 domain was one of the first described modular protein domains and was soon found to be involved in numerous important cellular functions and signalling cascades. Moreover, SH3 domain-mediated interactions were also found to be hijacked by pathogens, especially viruses, which developed highly specific proteins mimicking cellular SH3 domain ligands. This molecular mimicry allows the virus to interfere, manipulate and exploit host cellular signalling for its own benefits and survival. The vital elements of this doctoral thesis are the identification and characterization of so far unknown, high-affinity SH3 domain-mediated interactions and in the context of pathogenic SH3 domain ligand origin, also the elucidation of functional consequences for the host cell. The first part describes a large-scale screening approach uncovering high-affinity interactions between human SH3 domains and potential native target proteins. The identified robust SH3-mediated interactions are novel and thereby provide a valuable resource for future research. The second part extends the focus to SH3-mediated interactions between viruses and their host cells. These interactions are of exceptional impact since they enable the virus to manipulate or hijack the host’s immune defence system and thereby promote viral survival and propagation. Two examples of viral proteins binding via an SH3-mediated interaction to host cell factors are presented in this thesis: - the interaction of influenza A virus (IAV) NS1 protein with host cell Crk-adaptor proteins in context of reorganizing the Crk(L)-PI3 kinase signalling complex and – the interaction between molluscum contagiosum virus (MCV) MC159 protein and host cell SH3 binding protein 4 (SH3BP4). The study addressing the reorganization of the Crk(L)-PI3 kinase signalling complex by NS1, focuses on structural and biochemical aspects of a newly discovered trimeric protein complex and the related functional changes in downstream signalling, such as Akt activation. The work presented on MC159 identifies host cell SH3BP4 as a new target protein of MCV and shows that the SH3-mediated interaction between MC159 and SH3BP4 is essential for suppression of cellular autophagy by MC159.
  • Rantonen, Jarmo (Helsingin yliopisto, 2019)
    Background: Four out of five people will experience low back pain (LBP) during their lives. Most LBP episodes pass within one to three months, but about one third reoccur within one year. One in ten people suffer from chronic LBP. Because LBP mainly affects the working-age population, it often leads to serious socio-economic consequences at the personal, employer and societal level. Therefore, it is the most common disabling condition on a global scale. To prevent LBP from developing into a recurrent, chronic and potentially disabling condition, risk-based assessment and targeted interventions should be carried out in the early stage. Hence, the main questions regarding the prevention of LBP and its consequences are: At whom should preventive actions be targeted, how and when? Aims: This thesis evaluates the effectiveness of early-stage interventions offered to employees who reported disabling pain and stiffness in their low back area but were still able to work. Methods: An employee survey, recruitment of participants and secondary preventive interventions were carried out in an occupational health (OH) setting. Employees were selected for the study cohort and later categorized into ‘mild’ and ‘moderate’ LBP subgroups according to their responses in the employee survey, based on pre-defined, low back specific criteria. After this, the study participants were allocated into two randomized controlled trials, either the patient information option or the active rehabilitation option. A random sample represented the natural course of LBP as a no-intervention control for both trials. The effectiveness of the interventions was evaluated on the basis of low-back -specific outcomes and sickness absence in comparison to the those of the controls. In addition, health care resource utilization was evaluated in the patient information group. Results: In both subgroups, a secondary preventive approach showed improvements in some low-back-specific outcomes and quality of life in comparison to controls. In the ‘mild’ subgroup, health care costs decreased at the societal level in both patient information arms and booklet information was cost-effective. Sickness absence also decreased. Although absolute improvements were minor, the effects were substantial with respect to the low baseline levels. Conclusions: Early interventions are recommended for pre-defined, symptom-based employee groups as a preventive management strategy for disabling LBP in OH settings.
  • Andersson, Saana (Helsingin yliopisto, 2020)
    In 2016, 1742 men and 992 women were diagnosed with lung cancer in Finland (Finnish Cancer Registry, 2016). The 5-year survival of LC ranges from 8% to 20%. The aims of this study were to 1) evaluate surgical results and very long-term quality of life in patients operated on for central non-small cell lung cancer (NSCLC) using either pneumonectomy (PN) or sleeve lobectomy (SL); 2) examine whether the location of lymph-node positive NSCLC in mediastinum or hilum influences the survival of these patients, 3) the impact of video-assisted thoracic surgery (VATS) on very long-term health-related quality of life (HRQoL) and 4) investigate the learning curve of an experienced VATS surgeon when institutional robotic-assisted lobectomy was programmed. Study I included 641 NSCLC patients operated between 2000 to 2010. 67 had PN and 40 patients had SL. In 2011, all surviving patients were sent a 15D Quality-of-Life questionnaire. Propensity-score-matching analysis was utilized to compare the groups and overall 5-year survival, distant and locoregional recurrence pattern, and very-long term quality of life. In study II, we reviewed data of 881 operated NSCLC patients with R0 resection combined with mediastinal lymphadenectomy. Patients with unsuspected positive lymph node metastasis in hilar (N10) or mediastinal (N2) were analyzed. In study III, we evaluated 456 patients who underwent lobectomy for the treatment of NSCLC in VATS or conventional thoracotomy between 2006 and 2013. 199 patients were mailed the generic HRQoL instrument 15D. Very-long term quality of life was analyzed. For study IV, a retrospective comparison of a single surgeon that performed the first 75 VATS lobectomies between 2007 to 2012 and 75 robotic-assisted (RATS) lobectomies between 2011 to 2018. The data from the initial cases were evaluated and a cumulative sum (CUSUM) analysis was applied to the duration of the operations. In Study I, the 5-year survival, rate of distant metastasis or locoregional recurrence did not differ between groups. Very long-term quality of life measured by 15D did not reveal significant differences in separate dimensions or total score. In Study II, PFS was statistically significant better in superior mediastinal and aortic nodes versus inferior mediastinal nodes. The overall survival (OS) of positive hilar Naruke 10 did not differ from that of inferior mediastinal nodes. In Study III, patients that had lobectomy performed by VATS had significantly lower very-long term quality of life in the dimensions of breathing, speaking, usual activities, mental function, and vitality. In Study IV, the operative outcomes were similar between RATS and VATS groups. The analysis of the surgeon learning curves for VATS and RATS based on operative time reached proficiency at 53 VATS and 45 RATS. Sleeve operations have fewer major operative complications. PN should be considered in suitable patients if SL does not seem to be oncologically sufficiently radical. Inferior positive mediastinal N2 node patients seem to have OS and PFS as poor as multilevel N2 patients. The OS and PFS of patients with positive hilar disease are similar to those in the inferior mediastinal positive N2 group. Very long-term quality-of-life measures are poorer among patients who were treated with VATS compared to thoracotomy patients. In the treatment of local NSCLC, the perioperative results of RATS and VATS lobectomies of the same surgeon were equally good. Even if the surgeon is experienced, a long learning curve for robotic surgery implementation is required.
  • Komulainen, Kaisla (Helsingin yliopisto, 2019)
    Background. Cardiovascular etiologies are complex and influenced by several exposures acting together across the life-course. This dissertation examined the life-course pathways of cardiovascular health in relation to three intergenerational factors. First, we examined associations of genetic risk of higher body mass index (BMI) with BMI development, and whether the genetic associations differ by socioeconomic position (SEP) at different life stages (Study I). Second, we assessed intergenerational associations of ideal cardiovascular health behaviors between parents and their adult offspring, and whether these associations differ by SEP at different life stages (Study II). Third, we evaluated the association of favorable childhood psychosocial environment with adult cardiac structure and function (left ventricular (LV) mass (g/m2.7) and LV diastolic function (E/e’ ratio) and to which extent ideal cardiovascular health behaviors mediate these associations (Study III). Methods. Study participants were three subsamples from the prospective intergenerational Cardiovascular Risk in Young Finns Study (n=2441 in Study I, n=1856 in Study II, n=880 in Study III). We used data from follow-ups in 1980, 1983, 1986, 2001, 2007 and 2011. BMI was recorded in all follow-ups across 1980-2011. Genetic risk of BMI was assessed in 2001 with 97 single-nucleotide polymorphisms identified in the most recent GWAS meta-analysis. Four cardiovascular health behaviors – smoking, BMI, physical activity and diet – were recorded following the American Heart Association definitions. SEP was measured as educational attainment, income and occupational status. Adult SEP and health behaviors were self-reported or measured during a study visit in 1986, 2001, 2007 and 2011. Parental SEP and health behaviors were self-reported by parents of study participants in 1980. Childhood environment was assessed with a cumulative score comprising data from six relevant psychosocial domains reported by parents of study participants in 1980. Echocardiographic examination was conducted in 2011. Statistical analysis. Genetic associations with BMI development were analyzed with multilevel linear regression with random intercepts and random slopes. Intergenerational associations of health behaviors were assessed using ordinal and linear multilevel models with random intercepts. Associations of childhood psychosocial environment with adult cardiac structure and function and mediation pathways through cardiovascular health behaviors were assessed with marginal structural models in the causal mediation analysis framework. Results. In Study I, mean BMI increased from 22.6 to 26.6 kg/m2 during the follow-up. In growth curve analyses, the genetic risk score was associated with faster BMI increase over time (b=0.02, 95% CI, 0.01, 0.02 for genetic risk score x age interaction). The genetic associations with BMI were weaker among those with higher (vs lower) educational attainment in adulthood (b=-0.12, 95% CI, -0.23, 0.01 for genetic risk score x adult education interaction). At age 49, compared with those at the 10th percentile of the genetic risk score, those at the 90th percentile had 3.3 units higher predicted BMI at the lowest level of educational attainment and 2.4 units higher BMI at the highest level educational attainment. No interaction effect was observed between the genetic risk score and parental education (b=0.05, 95% CI, -0.09, 0.18 for genetic risk score x parental education interaction). In Study II, one additional ideal cardiovascular health behavior among parents was associated with 28% higher odds of one additional ideal behavior among offspring (odds ratio (OR)=1.28, 95% CI, 1.17,1.39). Furthermore, ORs for these intergenerational associations were greater among offspring who had higher own adult educational attainment or whose parents had higher educational attainment (OR=1.32 for high vs OR=1.04 for low offspring education; p=0.02 for interaction, OR=1.56 for high vs OR=1.19 for low parental education; p=0.01 for interaction). Similar trends were seen with parental income and offspring occupation. Results from linear regression analyses were similar. In Study III, favorable psychosocial environment in childhood was associated with more optimal cardiac structure and function in adulthood. Those above the median of the childhood score versus below the median had 1.28 g/m2.7 lower LV mass (95% CI=-2.63, 0.07) and 0.18 lower E/e’ ratio (95% CI=-0.39, 0.03). There was no evidence of indirect effects from childhood environment to LV outcomes through adult cardiovascular health behaviors after controlling for time-dependent confounding by adult SEP (indirect effect b=-0.30, 95% CI=-1.22, 0.63 for LV mass, b=-0.04, 95% CI=-0.18, 0.11 for E/e’ ratio). Results after multiple imputation were similar. Conclusions. These findings highlight the importance of intergenerational and early-life exposures in initiating pathways of long-term cardiovascular health and suggest these pathways may be shaped by socioeconomic circumstances at different life stages.
  • Szibor, Annett (Hansa Oy, 2019)
    Tinnitus, or the perception of sounds without an external source, affects up to 15% of the adult population worldwide. It relates to a number of psychological and psychiatric disorders such as psychological distress, insomnia and depression, and develops on a broad range of physical insults. To date, it is nearly impossible to obtain quantitative data on this symptom and thus complaints are often labelled as ‘only’ imaginary. Nevertheless, the sheer number of affected individuals makes it clear that tinnitus is everything but an orphan symptom. Variations in the clinical presentation may arise from the specific physical insult, the quality of first diagnosis and immediate medical aid as well as genetic predisposition. Thus, regional differences have to be considered when approaching tinnitus patients. The aim of this thesis was to study patient populations managed for tinnitus at the Department of Otorhinolaryngology - Head and Neck Surgery, Helsinki University Hospital (Helsinki, Finland). In the first study, we were able to show that music exposure even at low volume can pose a noise trauma and tinnitus occurs long before tone-audiometric hearing disabilities become evident. The alarming finding of the second study was its confirmation of pediatric tinnitus as a largely ignored symptom and that tinnitus in the childhood is under-diagnosed and this may have severe consequences for development of the individual. The third study could demonstrate that pupillometry can be considered as a viable option for studying autonomic activation in tinnitus subjects and emphasized the close link between tinnitus and depression. From our fourth study, a systematic literature review, we cannot clearly conclude if tinnitus and suicide are interrelated entities. The results of the last study indicate that tinnitus patients describe their own perceived tinnitus sound as well as external given sounds very divergent and therefore subjective tinnitus descriptions should be interpreted with great caution. Taken together, an early recognition of tinnitus symptoms may increase not only the overall quality of life of the affected patients, more importantly, it may decrease the risk of psychological and psychiatric co-morbidities and suicidal behavior. A major limitation still is that tinnitus lacks both, clear-cut biomarkers that are specific enough to be allocated solely to the symptom and methods that are sensitive enough to detect them.
  • Kivimäki, Anne (Helsingin yliopisto, 2019)
    Consumption of polyphenol-rich foods, such as berries, fruits, tea and cocoa has been claimed to exert beneficial effects on cardiovascular health. Wild Nordic berries, e.g. lingonberry (Vaccinium vitis-idaea), bilberry (Vaccinium myrtillus), cranberry (Vaccinium oxycoccos, V. microcarpum) and cultivated blackcurrant (Ribes nigrum) are good sources of polyphenols including flavonoids, such as anthocyanidins, proanthocyanidins and flavonols. The aim of this series of studies was to investigate the effects of cranberry, lingonberry and blackcurrant juices on vascular function of genetically hypertensive rats and to clarify how lingonberry affects the blood pressure of spontaneously hypertensive rats and normotensive rats consuming a high-salt diet. We also wanted to determine whether lingonberry juice could exert effects on low-grade inflammation, a phenomenon, which has been related to hypertension and excess salt intake. The established high blood pressure of spontaneously hypertensive rats became lowered during an eight-week treatment with lingonberry juice. However, more concentrated lingonberry juice was unable to prevent the development of genetic hypertension in young rats. Nonetheless, the endothelium-dependent relaxation of mesenteric arteries was enhanced after eight weeks’ treatment with the more concentrated lingonberry juice as was also the endothelium-independent relaxation. Positive effects of lingonberry juice on inflammatory markers were observed in both rat models. After lingonberry juice treatment, serum levels of both angiotensin II and alkaline phosphatase were lower than in the control groups. Possible anti-inflammatory and anti-thrombotic effects were present due to the reduced gene expression of cyclooxygenase 2 (COX2), monocyte chemoattractant protein 1, p-selectin and vascular cell adhesion molecule 1. These results indicate that inhibition of the renin-angiotensin system together with enhanced nitric oxide production could be possible mechanisms behind the positive effects on blood pressure and vascular function. The lingonberry treatment lowered gene expression of COX2 in the aorta, and increased COX2 protein expression in the kidney cortex macula densa, possibly indicating that inducible COX2 had been inhibited whereas the important constitutive COX2 was maintained by lingonberry treatment. Molecular docking studies conducted with flavonoid structures indicated that kaempferol may exert inhibitory effects on COX2. In summary, in an experimental model of hypertension, long-term treatment with lingonberry juice was able to lower blood pressure and improve vascular function. The effects on RAS and possible ACE1 inhibition together with enhanced nitric oxide bioavailability are potential mechanisms involved in these positive cardiovascular effects. Furthermore, lingonberry possesses anti-inflammatory properties, which may well contribute to its ability to reduce blood pressure and improve vascular function.
  • Vilander, Laura M. (Helsingin yliopisto, 2019)
    Objectives Acute kidney injury (AKI) is a complex syndrome that causes increased mortality and morbidity, especially in the critically ill. As clinical factors explain only part of the risk for AKI, individual susceptibility through genetic variation should be considered. The aims of this study were to systematically review the current literature for genetic predisposition to AKI, and to replicate previous findings in genes associating with apoptosis, iron metabolism, and inflammation in critically ill adults. Methods Study I was a systematic review about genetic predisposition to AKI risk and AKI-related outcomes. The review included 28 original studies. Studies II to IV included patients from the prospective, observational FINNAKI study that was conducted in 17 Finnish intensive care units in 2011 and 2012. Emergency admissions and elective admissions with an expected stay longer than 24h were included. Study II investigated the development of severe AKI and the association between variants in apoptosis-related genes: BCL2; SERPINA4; SERPINA5; and SIK3. Altogether 478 patients with septic shock were included. In Study III, the association between dinucleotide repeats in the intron of HMOX1 gene and the development of severe AKI was studied in 653 septic patients. In Study IV, the association between 27 candidate polymorphisms and the development of AKI was studied. The tested genetic variants were located within genes that have been previously linked with AKI. Results In Study I, the quality of the original studies was evaluated, but no meta-analysis was performed because of the heterogeneity of the studies. The studies gave no conclusive evidence. The majority of the variants were located within inflammatory genes and vasomotor-regulation-related genes with AKI development and AKI related outcomes. One investigation with a hypothesis-free study design was identified in Study I. In Study II,the association between variants in SERPINA4 and SERPINA5 and AKI was confirmed in an adjusted additive model. In Study III, in an additive genetic model, the short allele of the HMOX1 gene promoter repeat polymorphism was associated with increased odds for AKI. In Study IV, 27 genetic variants within inflammation-related genes were tested in association with AKI. None of the variants were significantly associated with AKI in any of the analyses. Main conclusions The systemic review conducted provides no conclusive evidence about the genetic predisposition to AKI. The reviewed studies were of inadequate quality and heterogeneous. In the phenotype of AKI with septic shock, the apoptosis-related genes are inflicted in AKI pathophysiology. Moreover, in critically ill patients with sepsis the repeat polymorphism in the HMOX1 gene promoter sequence had the opposite risk allele for the development of severe AKI than previously found in cardiac-surgery patients. In conclusion, the majority of the previously suggested candidate gene variants tested in association with development of AKI were not confirmed in this large multicenter prospective study in critically ill patients.
  • Itkonen, Matti (Helsingin yliopisto, 2019)
    Clopidogrel, an adenosine diphosphate receptor subtype P2Y12 antagonist, attenuates platelet activation via its active cis-thiol metabolite formed in two steps predominantly by cytochrome P450 (CYP) 2C19 and CYP3A4. It is widely used in acute treatment and secondary prevention of atherothrombotic events. The acyl-β-D-glucuronide metabolite of clopidogrel acts as a time-dependent inhibitor of CYP2C8 in vitro, and consistently, clopidogrel markedly increases the exposure of the CYP2C8 and OATP1B1 substrate repaglinide in vivo. The primary aim of this work was to examine the potential of clopidogrel to cause drug-drug interactions (DDIs) with OATP1B1 and CYP2C8 substrates, while the secondary objective was to search for sensitive and selective CYP2C8 index substrates. This thesis consists of five prospective, clinical pharmacokinetic and pharmacodynamic DDI studies applying randomized, controlled, crossover design. In the first study, clopidogrel did not affect the pharmacokinetics of simvastatin, leading to the conclusion that clopidogrel is not a clinically relevant inhibitor of OATP1B1 or CYP3A4, which have paramount roles in the disposition of simvastatin. In the second and third studies, clopidogrel doubled the exposures of the CYP2C8 substrates pioglitazone and montelukast, respectively. In contrast, prasugrel did not significantly affect montelukast pharmacokinetics. The fourth study found clopidogrel to increase the exposure of the CYP2C8 substrate dasabuvir ~4–5-fold and observed ritonavir to markedly decrease the exposure of clopidogrel active metabolite and its antiplatelet effect. The results from the fourth study indicated that dasabuvir is a very sensitive and specific CYP2C8 substrate and that combining clopidogrel with dasabuvir or ritonavir with clopidogrel may risk patient safety. In the fifth study, clopidogrel significantly inhibited, and gemfibrozil almost completely prevented, the CYP2C8-mediated 3-hydroxylation of desloratadine. In conclusion, clopidogrel is a clinically relevant CYP2C8 inhibitor capable of causing potentially hazardous DDIs, and it can be employed as a selective index inhibitor of CYP2C8 in clinical DDI studies. Furthermore, dasabuvir could be applied as a CYP2C8 index substrate in subtherapeutic doses in clinical drug research. Moreover, the observations from this work corroborate the ability of ritonavir to disrupt CYP3A4-mediated bioactivation of prodrugs, including clopidogrel, which can compromise patient safety. Finally, these results highlight the ability of glucuronide metabolites to act as substrates and inhibitors of CYP enzymes, especially CYP2C8, and therefore they must be considered as potentially interacting compounds during drug development.
  • Hauta-alus, Helena (Helsingin yliopisto, 2019)
    Vitamin D is vital for normal growth and development. Vitamin D is produced endogenously in the skin after sunlight exposure or obtained from dietary sources. In Finland, solar radiation is inadequate for cutaneous vitamin D synthesis in winter, leading to a high risk for vitamin D insufficiency, defined by circulating 25-hydroxyvitamin D concentration [25(OH)D] below 50 nmol/l. Poor maternal 25(OH)D has been associated with adverse pregnancy and neonatal outcomes, such as pre-eclampsia, gestational diabetes mellitus (GDM), and low birth weight. Only a few studies have explored the relationship between vitamin D and infant postnatal growth, and these studies show inconsistent results. Further, data on current maternal vitamin D status and infant vitamin D intake in Finland are lacking. The objectives of this thesis were to 1) define maternal and newborn 25(OH)D concentrations and characterize maternal determinants of vitamin D status during pregnancy; 2) examine whether vitamin D status differs between mothers with and without GDM; 3) describe vitamin D intake from food and identify food sources of vitamin D in 1-year-old infants, and finally, 4) investigate whether maternal or infant vitamin D status associate with pre- and postnatal infant growth. This thesis is part of the Vitamin D Intervention in Infants (VIDI) study. At Helsinki Maternity Hospital, 987 families were recruited to the study from January 2013 to June 2014. Infants were randomized to daily supplemental vitamin D dosages of 10 µg or 30 µg from 2 weeks until 2 years of age. Mothers were of Northern European ethnicity without regular medication. Infants were born at term with birth weights appropriate for gestational age. Maternal serum samples were collected at prenatal clinics between 2012 and 2013 in early pregnancy. At birth, umbilical cord blood (UCB) was obtained. Circulating 25(OH)D was analyzed with IDS-iSYS from pregnancy, UCB and infant serum samples at 1 year of age. Maternal dietary patterns were derived from a 22-item food frequency questionnaire and infant vitamin D intake was assessed with a 3-day food record. GDM diagnosis and data on infant birth size were obtained from medical records. Infant growth was measured at study visits at the ages of 6 months and 1 year. Overall, the pregnant women and their newborns were vitamin D sufficient as the concentration of 25(OH)D in 96% of all subjects was ≥50 nmol/l. Of pregnant women, 95% used vitamin D supplements with a mean daily intake of 16 µg. Maternal positive predictors of 25(OH)D during pregnancy, based on 25(OH)D from early pregnancy to UCB, were supplemental vitamin D intake, a dietary pattern characterized by regular use of vitamin D–fortified foods and prepregnancy physical activity. In contrast, factors associating with declining 25(OH)D during pregnancy were smoking and multiparity. GDM was observed in 11% of the pregnant women. Maternal 25(OH)D concentrations did not differ between GDM and non-GDM women. Furthermore, 25(OH)D had no relation to oral glucose tolerance test results. Mean daily intake of vitamin D from food was 7.5 µg in non-breastfed and 3.8 µg in breastfed 1-year-old infants. The main food sources of vitamin D were infant formula, dairy milk, porridge, and fish foods. Higher maternal and infant 25(OH)D were associated with slower infant growth. At 6 months of age, infants to mothers with high pregnancy 25(OH)D (>125 nmol/l) were the shortest (in length), lightest (in weight), and thinnest (in length-adjusted weight). Higher UCB 25(OH)D had an inverse association with head circumference at birth and infant length at 6 months. In infants, higher UCB 25(OH)D associated with slower linear growth from birth to 6 months, but an accelerated growth from 6 months to 1 year of age. Infants with 25(OH)D >125 nmol/l were the lightest and thinnest at 1 year of age, whereas mothers with UCB 25(OH)D <50 nmol/l had the thinnest infants at 6 months. In conclusion, vitamin D status was sufficient among pregnant women in Finland. Likewise, infants who participated in a vitamin D supplementation trial had sufficient vitamin D status at 1 year of age. High maternal and infant 25(OH)D associated with slower infant growth. These results may indicate a possible inverse U-shaped relationship between vitamin D status and growth. The clinical relevance of this finding remains unknown. Until more data emerge, there is no need to aim for higher maternal or infant 25(OH)D concentrations beyond vitamin D sufficiency with excessive supplementation as this may have disadvantageous effects on infant growth.

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