• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 8
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 21
  • 21
  • 13
  • 12
  • 6
  • 5
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Structural and functional characterization of a novel endogenous steroid, estradienolone (ED), in human pregnancy

Hébert-Losier, Andréa, 1983- January 2008 (has links)
Our lab has previously reported the identification of a novel endogenous 19-nor steroid, estradienolone (ED), in pregnant women that strongly bound to sex hormone binding globulin. Estrogen-receptor related receptors (ERRs), which have no known natural ligands, are a family of orphan receptors consisting of 3 isoforms: ERRalpha, ERRbeta and ERRgamma. The ERRs have been shown to actively modulate estrogenic responses, to play an essential role in pregnancy, and are implicated in breast cancer prognosis. My results show that ED acts as an antagonist of the ERRalpha confirming preliminary results obtained by our group. Studies of cellular responses demonstrate that ED has strong anti-mitogenic properties. ED inhibited the growth of both estrogen receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) breast cancer cells in a dose-dependent manner but did not have any effects on the proliferation of the non-cancerous immortalized epithelial breast MCF-10A cells. The finding that ED inhibits proliferation of both ER negative and ER positive breast cancer cells, and regulate ERR transcriptional activity may have important ramifications in breast cancer therapy.
12

Steroid-Metabolizing Cytochrome P450 (CYP) Enzymes in the Maintenance of Cholesterol and Sex Hormone Levels

Pettersson, Hanna January 2009 (has links)
The enzymes CYP27A1 and CYP7B1 are widely expressed in various human tissues and perform catalytic reactions in cholesterol homeostasis and endocrine signaling. We have investigated the metabolism of a synthetic oxysterol. In this study, we show that CYP27A1 is the enzyme responsible for a 28-hydroxylation of this oxysterol and that the rate of CYP27A1-mediated metabolism is relatively slow. This may give an explanation for the prolonged inhibitory effects on cholesterol biosynthesis that have been shown for this oxysterol. The current study contributes to the knowledge of synthetically produced oxysterols and their potential use as cholesterol lowering drugs. In two studies we investigated CYP7B1-mediated metabolism of different sex hormones. Our data indicate that CYP7B1 may carry out a previously unknown catalytic reaction involving an androgen. Taken together the data suggest that varying steroid concentrations in cells and tissues may be important for CYP7B1-dependent metabolism of sex hormones and sex hormone precursors. CYP7B1-mediated hydroxylation of sex hormones may influence the cellular levels of these steroids and may be a potential pathway for elimination of the steroids from the cell. Some known CYP7B1 substrates are agonists for ERα and ERβ but the reported role(s) of CYP7B1 for ER action are not fully understood. In the last study we investigated the role(s) of CYP7B1-mediated metabolism for ER-mediated action. Our data indicate that CYP7B1-mediated conversion of steroids that affect ER-mediated response into their 7α-hydroxymetabolites will result in loss of action. This indicates that CYP7B1 may have an important role for regulation of ER-mediated processes in the body. In summary, results from this thesis contribute to the knowledge on the metabolism of synthetic oxysterols of potential use as cholesterol lowering drugs and the role(s) of CYP7B1-mediated metabolism for processes related to the functions of sex hormones. / Disputationsordförande;Professor Eva Brittebo, Inst. för Biovetenskap, Avd. för Toxikologi, Uppsala Universitet, UppsalaBetygsnämndens ledamöten; Docent Lena Ekström, Inst. för Laboratoriemedicin, Avd. för Klinisk Kemi, Karolinska Universitetssjukhuset, HuddingeDocent Ulf Diczfaluzy, Inst. för Laboratoriemedicin, Avd. för Klinisk Kemi, Karolinska Universitetssjukhuset, HuddingeProfessor Agneta Oskarsson, Inst. BVF, Avd. för farmakologi och toxikologi, SLU, Uppsala
13

Enzymatic Regulation of Steroidogenesis and Nuclear Receptor Activation : Special Focus on Vitamin D and Sex Hormones

Lundqvist, Johan January 2011 (has links)
Enzyme-catalyzed reactions are important to regulate steroidogenesis and nuclear receptor activation. The present investigation examines the role of steroid metabolism catalyzed by CYP7B1 for regulation of hormone receptor activation and the effects of vitamin D on enzymatic regulation of steroidogenesis. The study reports data indicating that CYP7B1 can regulate estrogenic signaling by converting estrogens into inactive or less active metabolites. Similar results were obtained for CYP7B1-mediated metabolism of some androgen receptor ligands, indicating that CYP7B1 can be involved also in the regulation of androgenic signaling. CYP7B1 substrates and metabolites were found to exert androgenic effects in a cell line-specific manner. Furthermore, cell line differences were observed in the expression pattern for androgen receptor comodulators. This thesis reports that 1α,25-dihydroxyvitamin D3 alters the gene expression and enzyme activity of CYP21A2 and CYP17A1 leading to suppressed production of aldosterone, dehydroepiandrosterone and androstenedione in adrenocortical cells. These are novel findings on vitamin D action. A mechanism is reported for the vitamin D-mediated regulation of the CYP21A2 gene. Data indicate that vitamin D receptor interacting repressor (VDIR) and Williams syndrome transcription factor (WSTF) are key comodulators in this novel vitamin D receptor (VDR)-mediated mechanism. Furthermore, the results indicate that altered expression levels of VDIR and WSTF can shift the suppressing effect of vitamin D to a stimulatory effect. Also, epigenetic components were found to be involved in the effects of vitamin D on CYP21A2 transcriptional rate. In addition, a functional vitamin D response element was identified in the CYP21A2 promoter. This study also reports that 1α,25-dihydroxyvitamin D3 affects sex hormone production in a tissue-specific way. Gene expression and enzyme activity of aromatase were found to be downregulated in cells derived from breast, but not in cells derived from prostate and adrenal cortex. The production of estradiol and dihydrotestosterone was altered in a tissue-selective manner following vitamin D treatment. These findings are of importance for the discussion on vitamin D as a potential anti-breast cancer agent.
14

Testosterona, estradiol e doença arterial coronariana em homens adultos / Testosterone, estradiol and coronary artery disease in men

Callou, Emmanuela Quental [UNIFESP] 28 April 2010 (has links) (PDF)
Made available in DSpace on 2015-07-22T20:50:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-28 / Introdução: As doenças cardiovasculares (DCVs) representam o principal grupo de causa de morte no Brasil, com destaque para doença arterial coronariana (DAC). O sexo masculino apresenta maior incidência e mortalidade por DAC que o feminino. Uma das explicações para o fato era o possível efeito deletério da Testosterona no sistema cardiovascular masculino e o efeito protetor do Estradiol no sistema cardiovascular feminino. Contudo, evidências recentes da literatura apontam para um efeito protetor ou neutro da Testosterona no aparelho cardiovascular masculino, enquanto níveis elevados de Estradiol nos homens estiveram correlacionados com maior morbidade e mortalidade por doenças cardiovasculares. Objetivos: Realizar uma revisão da literatura da relação existente entre Testosterona sérica e doença cardiovascular em homens adultos; Avaliar a relação existente entre Testosterona Total, Testosterona Biodisponível, Testosterona Livre, Índice de Andrógenos Livres (IAL), Globulina Ligadora de Esteróides Sexuais (SHBG), Estradiol, Índice de Estrógenos Livres (IEL), relação Estradiol / Testosterona e a relação IEL / IAL e doença arterial coronariana em homens adultos; Entender o papel da Globulina Ligadora de Esteróides Sexuais como novo componente as síndrome metabólica. Material e Métodos: A revisão da relação entre testosterona e doença cardiovascular foi realizada através da base de dados do PubMed com a utilização dos unitermos testosterona e doença cardiovascular; a avaliação da relação existente entre esteróides sexuais e DAC foi realizada através de um estudo de caso controle com homens adultos submetidos ao Cateterismo de Artérias Coronárias no Instituto Dante Pazzanese de Cardiologia; o entendimento do papel da SHBG como novo componente as síndrome metabólica através da análise dos dados obtidos do estudo “Estradiol but not Testosterone is Related to Coronary Artery Disease”. Resultados: Os resultados foram dispostos em 03 artigos, a saber: ARTIGO 1 “Testosterona Sérica e Doença Cardiovascular em Homens”; ARTIGO 2 “Estradiol but not Testosterone is Related to Coronary Artery Disease in Men”; ARTIGO 3 (preparando para a submissão) “Sex hormone binding globulin a novel component of metabolic syndrome”. Conclusões: Os estudos selecionados da literatura que avaliaram a relação entre testosterona e doença cardiovascular apresentavam pequeno número de participantes e amostras selecionadas, ornando necessário que novos estudos avaliem o papel da testosterona na DCV nos homens. Os achados apresentados sinalizam para uma correlação positiva entre níveis séricos de Estradiol e IEL com DAC. Foram observados efeitos neutros da testosterona total, testosterona biodisponível, testosterona livre, índice de andrógenos livres SHBG, relação Estradiol / Testosterona e relação IEL / IAL na incidência dessa patologia. Baixos níveis de SHBG parecem se correlacionar positivamente com os componentes da síndrome metabólica, sendo necessários novos estudos que avaliem esse parâmetro como novo componente desta Síndrome. / Introduction: Cardiovascular diseases (CVDs) represent the main cause of death in Brazil, and among them especially the coronary artery diseases (CADs). Men present higher incidence and mortality rates for CAD than women. One of the explanations for this fact may be the possibly deleterious effect of testosterone on the male cardiovascular system and the protective effect of estradiol on the female cardiovascular system. However, recent studies in the literature indicate that testosterone has an either protective or neutral effect on the male cardiovascular system, while high levels of estradiol in men have been correlated to higher rates of morbidity and mortality from cardiovascular diseases. Objectives: To carry out a review of the literature regarding the relationship between testosterone and cardiovascular disease in men, to evaluate the existing relationships among total testosterone, bioavailable testosterone, free testosterone, free androgen index (FAI), sex hormone binding globulin, estradiol, free estrogen index (FEI), estradiol/testosterone ratio and FEI/FAI ratio and coronary artery disease in men; to understand the role of the sex hormone binding globulin as a new component of the metabolic syndrome. Material and Methods: The review of the literature regarding the relationship between testosterone and cardiovascular disease was performed using the PubMed database and the keywords testosterone and cardiovascular disease. The relationship between sex steroids and CAD was evaluated by a case-control study performed on men submitted to coronary angiography at the Instituto Dante Pazzanese de Cardiologia. The role of the sex hormone binding globulin (SHBG) as a new component of the metabolic syndrome was evaluated using the data obtained by the study “Estradiol but not Testosterone is Related to Coronary Artery Disease”. Results: The results were presented in three articles, namely: ARTICLE 1 - “Serum Testosterone and Cardiovascular Disease in Men”; ARTICLE 2 - “Estradiol but not Testosterone is Related to Coronary Artery Disease in Men”; ARTICLE 3 - (being prepared for submission) - “Sex hormone binding globulin, the novel component of metabolic syndrome?”. Conclusions: The studies retrieved from the literature which evaluated the relationship between testosterone and cardiovascular disease presented small numbers of participants and selected samples, which indicated the need for further studies to evaluate the role of testosterone in CVD in men. The findings presented suggest a positive correlation between estradiol and FEI levels with CAD. A neutral effect of total testosterone, bioavailable testosterone, free testosterone, free androgen index, SHBG, estradiol/testosterone ratio and FEI/FAI ratio on the incidence of this pathology was observed. Low levels of SHBG seem to correlate positively with the components of the metabolic syndrome, but further studies are necessary to evaluate this parameter as a new component of this syndrome. / TEDE / BV UNIFESP: Teses e dissertações
15

Caracteriza??o comportamental end?crina das fases ontogen?ticas de sag?i comum (Callithrix jacchus) / Caracteriza??o comportamental end?crina das fases ontogen?ticas de sag?i comum (Callithrix jacchus)

Castro, Dijenaide Chaves de 11 November 2011 (has links)
Made available in DSpace on 2014-12-17T15:36:38Z (GMT). No. of bitstreams: 1 DijenaideCC_TESE.pdf: 3067760 bytes, checksum: 8bdbafb50f4741aa87b6e7ea5023d6a3 (MD5) Previous issue date: 2011-11-11 / The use of animal models in biomedical research is ever increasing. Models that use primates might also have advantages in terms of low maintenance costs and availability of biological knowledge, thereby favoring their use in different experimental protocols. Many current stress studies use animal models at different developmental stages since biological response differs during ontogeny. The aims of this study were to perform a detailed characterization of the developmental stages of common marmosets (Callithrix jacchus), a very important animal model used in biomedical research. Ten subjects, 6 females and 4 males, were followed from birth to initial adult age (16 months). Behavioral and fecal collection for measurement of adrenal (cortisol) and sex (progesterone, estradiol and androgens) hormones took place twice a week during the first month of life and once a week for the remainder of the study. Behavior was observed for 30 minutes in the morning (0700-09:00h) and afternoon (12:00-14:00h). Behavioral profile showed changes during ontogeny, characterizing the 4 developmental stages and the respective phases proposed by Le?o et al (2009).. Differentiation of developmental stages was considered using the onset, end, change and stabilization of the behavioral profile parental care (weaning and carrying), ingestion (solid food), affiliation (social grooming) and autogrooming, agonism (scent marking and piloerection) and play behavior and endocrine profile. Infant weaning and carrying terminated within the infantile stage and the peak of solid food ingestion was recorded in the infantile III phase. Receiving grooming was recorded earlier than grooming performed by the infant and autogrooming. The first episode of scent marking was recorded in the 4th week and it was the least variable behavior, in terms of its onset, which, in almost all animals, was between the 5th and 7th week of life. Solitary play and play with the twin started around the 7th week and play with other members of the group started 8 weeks later. Sex hormone secretion started to differ from basal levels between the 21st and 23rd week of life, in males and females, suggesting that puberty occurs simultaneously in both sexes. Basal cortisol, even at an early age, was higher in females than in males. However, cortisol was not correlated with the juvenile stage, as expected, since this stage corresponds to the transition between infancy and adult age and most behaviors are intensified by this time. The behavioral and endocrine profile of subadult animals did not differ from that of the adults. These results provide more detailed parameters for the developmental process of C. jacchus and open new perspectives for the use of experimental approaches focused on the intermediate ontogenetic phases of this species / O uso de modelos animais em pesquisa biom?dica ? cada vez mais crescente e os modelos utilizando primatas devem apresentar vantagens em termos de custos de manuten??o e caracter?sticas relacionadas ao maior conhecimento da sua biologia para uso em diferentes protocolos experimentais. Diferentes modelos atuais de pesquisa em estresse utilizam animais em diferentes est?gios do desenvolvimento e in?meros estudos demonstram a diferen?a na resposta biol?gica diante de agentes estressores ao longo da ontog?nese. Com o objetivo de caracterizar de maneira mais detalhada as fases do desenvolvimento do sagui comum, Callithrix jacchus, importante modelo utilizado em pesquisa biom?dica, utilizou-se 10 animais, 6 f?meas e 4 machos, que foram acompanhados desde o nascimento at? o in?cio da idade adulta (16 meses). A coleta de dados comportamentais e de fezes para a mensura??o dos horm?nios esteroides de origem adrenal (cortisol) e gonadais (progesterona, estradiol e andr?genos) foram realizadas duas vezes por semana no primeiro m?s de vida dos filhotes e semanalmente no restante do estudo. As observa??es comportamentais tiveram dura??o de 30 minutos e foram realizadas nos turnos matutino (07:00-09:00h) e vespertino (12:00-14:00h).O perfil comportamental de C. jacchus apresentou modifica??es ao longo da ontog?nese caracterizando cada um dos 4 est?gios ontogen?ticos e suas respectivas fases propostas na classifica??o de Le?o (2009). A diferencia??o das etapas do desenvolvimento foi feita a partir do surgimento, t?rmino, varia??o e estabiliza??o no perfil comportamental - cuidado parental (amamenta??o, transporte) ingest?o de alimentos (alimenta??o s?lida), afilia??o (cata??o social recebida e feita e autocata??o) agonismo (marca??o de cheiro e piloere??o) e brincadeira - e no perfil end?crino. O comportamento de amamenta??o e transporte terminou na fase infantil II e a ingest?o alimentar apresentou seu pico na fase infantil III. A cata??o social recebida antecedeu a cata??o feita e a autocata??o, e o comportamento de marca??o de cheiro foi o que apresentou menor variabilidade em rela??o ao seu in?cio, que se concentrou, em quase todos os animais, entre a 5? e 7? semanas de vida. A brincadeira solit?ria e com o g?meo principiaram ao redor da 7? semana e a brincadeira com outros membros do grupo se iniciou 8 semanas depois. A secre??o dos horm?nios sexuais passou a se diferenciar dos valores basais entre a 21? e 23? semanas em machos e f?meas, sugerindo que a puberdade acontece simultaneamente para os dois sexos. O cortisol basal de f?meas mesmo em idade imatura foi mais elevado do que nos machos. Contudo, as varia??es do cortisol n?o se correlacionaram com o est?gio juvenil como esperado uma vez que esse est?gio corresponde ? transi??o entre a idade infantil e a idade adulta, e que se expressou com a intensifica??o da maioria dos comportamentos. Os padr?es comportamentais e end?crinos dos adultos n?o diferiram entre as idades subadulta e adulta. Estes resultados disponibilizam par?metros de desenvolvimento mais detalhados para C. jacchus e abrem perspectivas para a utiliza??o de abordagens experimentais focadas em determinadas etapas da ontog?nese dessa esp?cie
16

Binding of radiographic contrast media to serum proteins : a clinical and experimental investigation of their adverse effects through influence on active steroid hormone levels

Wirell, Staffan January 1982 (has links)
<p>S. 1-40: sammanfattning, s. 41-96: 5 uppsatser</p> / digitalisering@umu.se
17

Structural and functional characterization of a novel endogenous steroid, estradienolone (ED), in human pregnancy

Hébert-Losier, Andréa, 1983- January 2008 (has links)
No description available.
18

Prenatal Exposure to Perfluoroalkyl Acids and Serum Testosterone Concentrations at 15 Years of Age in Female ALSPAC Study Participants

Maisonet, Mildred, Calafat, Antonia M., Marcus, Michele, Jaakkola, Jouni J.K., Lashen, Hany 01 December 2015 (has links)
Background: Exposure to perfluorooctane sulfonic acid (PFOS) or to perfluorooctanoic acid (PFOA) increases mouse and human peroxisome proliferator–activated receptor alpha (PPARα) subtype activity, which influences lipid metabolism. Because cholesterol is the substrate from which testosterone is synthesized, exposure to these substances has the potential to alter testosterone concentrations. Objectives: We explored associations of total testosterone and sex hormone–binding globulin (SHBG) concentrations at age 15 years with prenatal exposures to PFOS, PFOA, perfluorohexane sulfonic acid (PFHxS), and perfluoronanoic acid (PFNA) in females. Methods: Prenatal concentrations of the perfluoroalkyl acids (PFAAs) were measured in serum collected from pregnant mothers at enrollment (1991–1992) in the Avon Longitudinal Study of Parents and Children (ALSPAC). The median gestational age when the maternal blood sample was obtained was 16 weeks (interquartile range, 11–28 weeks). Total testosterone and SHBG concentrations were measured in serum obtained from their daughters at 15 years of age. Associations between prenatal PFAAs concentrations and reproductive outcomes were estimated using linear regression models (n = 72). Results: Adjusted total testosterone concentrations were on average 0.18-nmol/L (95% CI: 0.01, 0.35) higher in daughters with prenatal PFOS in the upper concentration tertile compared with daughters with prenatal PFOS in the lower tertile. Adjusted total testosterone concentrations were also higher in daughters with prenatal concentrations of PFOA (β = 0.24; 95% CI: 0.05, 0.43) and PFHxS (β = 0.18; 95% CI: 0.00, 0.35) in the upper tertile compared with daughters with concentrations in the lower tertile. We did not find evidence of associations between PFNA and total testosterone or between any of the PFAAs and SHBG. Conclusions: Our findings were based on a small study sample and should be interpreted with caution. However, they suggest that prenatal exposure to some PFAAs may alter testosterone concentrations in females.
19

Endogenous hormones in the etiology of ovarian and endometrial cancers

Lukanova, Annekatrin January 2004 (has links)
The main purpose of this thesis was to examine the relationship of pre-diagnostic circulating levels of sex-steroids (androgens and estrogens), sex hormone binding globuline (SHBG), insulin-like growth factor-I (IGF-I), IGF binding proteins (BP) and C-peptide (as a marker of pancreatic insulin secretion) with risk of ovarian and endometrial cancer. Additionally, the interrelationships of body mass index (BMI), sex-steroids, IGF-I and IGFBP-3 were examined. Two case-control studies were nested within 3 prospective cohort studies centered in New York (USA), Umeå (Sweden) and Milan (Italy). The ovarian study included 132 cancer cases. The endometrial study included 166 cancer cases in the IGF-I and C-peptide component and 124 postmenopausal cases in the sex-steroids component. For each case, two controls matching the case for cohort, age, menopausal status and date at recruitment were selected. In total 286 and 315 controls were included in the ovarian and endometrial cancer studies, respectively. Odds ratios (OR) and their 95% confidence intervals (CI) for cancer risk associated with increasing hormone concentrations were estimated by conditional logistic regression. The cross-sectional analysis was based on anthropometric and hormonal data from 620 controls selected for the two nested case-control studies. There was no association of prediagnostic androstenedione, testosterone, DHEAS, SHBG or estrone with ovarian cancer risk in the whole study population or in women who were pre- or postmenopausal at blood donation. In the premenopausal group, risk appeared to increase with increasing androstenedione (OR (95% CI) for the highest tertile: 2.35 (0.81-6.82), p=0.12). There was no association of IGF-I, IGFBP-1, 2, 3 or C-peptide concentrations with risk of ovarian cancer risk in the study group as a whole. In analyses restricted to subjects who had developed ovarian cancer at an early age (&lt;55), circulating IGF-I was directly and strongly associated with risk (OR (95% CI): 4.74 (1.20-18.7), p&lt;0.05 for the highest IGF-I tertile). In the endometrial study, previous observations were confimed that elevated circulating estrogens and androgens and decreased SHBG increase risk of developing endometrial malignancy after menopause. Multivariate ORs (95% CI) for endometrial cancer for quartiles with the highest hormone levels were: 4.13 (1.76-9.72), p&lt;0.001 for estradiol; 3.67 (1.71-7.88), p=0.001 for estrone; 2.15 (1.05-4.40), p&lt;0.04 for androstenedione; 1.74 (0.88-3.46), p=0.06 for testosterone; 2.90 (1.42-5.90), p&lt;0.01 for DHEAS and 0.46 (0.20-1.05), p&lt;0.01 for SHBG. Prediagnostic IGF-I, IGFBP-1, -2 and –3 were not related to risk of endometrial cancer in the whole study population. In postmenopausal women, levels of IGFBP-1 were inversely related to risk with an OR for the highest quartile of 0.36 (0.13-0.95), p&lt;0.05. Endometrial cancer risk increased with increasing levels of C-peptide (p&lt;0.01), up to an OR of 4.40 (1.65-11.7) for the highest quintile after adjustment for BMI and other confounders. The cross-sectional analyses showed that in both pre- and postmenopausal women SHBG decreased with increasing BMI. In the postmenopausal group, estrogens, testosterone and androstenedione increased with BMI, while the association with IGF-I was non-linear, the highest mean IGF-I concentration being observed in women with BMI between 24 and 25. In postmenopausal women, IGF-I was positively related to androgens, inversely correlated with SHBG, and was not correlated with estrogens. In conclusion, elevated pre-diagnostic sex-steroids, IGF-I or C-peptide increase risk of developing ovarian and endometrial cancer. BMI influences the circulating levels of these hormones, especially after menopause.
20

Epidemiological applications of quantitative serum NMR metabolomics:causal inference from observational studies

Wang, Q. (Qin) 10 March 2017 (has links)
Abstract Cardiovascular diseases are the leading cause of death worldwide and type 2 diabetes is reaching a global epidemic. Epidemiological studies have identified numerous risk factors and pharmacotherapies in relation to these cardiometabolic diseases. However, the detailed molecular mechanisms of these risk factors and drug therapies generally remain incompletely understood. Elucidating the underlying molecular effects would be essential for better understanding of the disease pathogenesis and also for discovering new therapeutic targets. Quantitative serum metabolomics, which allows for simultaneous quantification of multiple circulating metabolic measures, provides a hypothesis-free approach to systematically inspect the metabolic changes in response to endogenous and exogenous stimuli. Metabolomics thus presents a valuable tool to study the detailed molecular effects of disease risk factors and drug therapies. However, current metabolomics studies are mostly conducted in small cross-sectional studies and the causal relations of the risk factors on the metabolic measures are generally unclear, providing limited public health impact. The present thesis serves as a proof-of-concept to illustrate that well-designed observational studies can be used to infer causality. With the exemplars of assessing molecular effects of two risk factors (body mass index and sex hormone-binding globulin) and two drug therapies (statins and oral contraceptives), the thesis demonstrates that an improved causal inference can be achieved in observational studies via the combination of multiple study designs, including cross-sectional, longitudinal and Mendelian randomization analysis. This robust study design approach together with metabolomics data can be also extended to study the molecular effects of other risk factors and drug therapies. With an improved molecular understanding of a wide range of risk factors and therapies, better understanding of disease pathogenesis is ensured. / Tiivistelmä Sydän- ja verisuonitaudit ovat johtava kuolinsyy maailmassa ja tyypin 2 diabetes on saavuttamassa globaalin epidemian mittasuhteet. Epidemiologiset tutkimukset ovat löytäneet useita riskitekijöitä ja lääkehoitoja edellä mainituille yleisille taudeille. Tyypin 2 diabetekseen ja sydän- ja verisuonitauteihin liittyvät yksityiskohtaiset molekylaariset mekanismit ymmärretään kuitenkin puutteellisesti. Molekylaaristen yksityiskohtien tarkempi ymmärtäminen olisi siten erittäin merkittävää sekä tautiprosessien ymmärtämiseksi että lääkehoitojen kehittämiseksi. Seerumin kvantitatiivinen metabolomiikka mahdollistaa useiden metabolisten suureiden samanaikaisen määrittämisen verenkierrosta ja tarjoaa siten hypoteesittoman lähestymistavan sekä sisäisten että ulkoisten ärsykkeiden aiheuttamien metabolisten muutosten systemaattiseen tutkimukseen. Metabolomiikka on siten arvokas työkalu yksityiskohtaisten molekylaaristen mekanismien tutkimuksessa, olipa kyseessä taudin riskitekijät tai lääkehoito. Metabolomiikkatutkimuksia on kuitenkin pääasiassa tehty pienissä poikittaistutkimuksissa ja riskitekijöihin liittyvien metabolisten suureiden syy- ja seuraussuhteet ovat yleisesti epäselviä, josta johtuen metabolisten suureiden kansanterveydellinen sovellettavuus on ollut heikkoa. Tämä väitöskirja esittelee tutkimuskonseptin hyvin suunniteltujen havaintotutkimuksien soveltamiseksi syy- ja seuraussuhteiden arvioinnissa. Työ sisältää esimerkit kahden riskitekijän (painoindeksi ja sukupuolihormoneja sitova globuliini) ja kahden lääkehoidon (statiinit ja ehkäisypillerit) molekylaaristen vaikutusten kausaalisista tutkimuksista. Tulokset havainnollistavat, että kausaalisten johtopäätösten luotettavuutta voidaan parantaa yhdistämällä useita tutkimusasetelmia, kuten poikittais- ja pitkittäistutkimuksia sekä Mendelististä satunnaistamista. Esitettyjä luotettavia tutkimusasetelmia, yhdessä metabolomiikkadatan kanssa, voidaan laajentaa muiden riskitekijöiden ja lääkehoitojen molekylaaristen vaikutusten tutkimuksiin. Parantunut molekyylitason ymmärrys useista riskitekijöistä ja lääkehoidoista johtaa myös parempaan tautiprosessien ymmärtämiseen.

Page generated in 0.1987 seconds