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Efeitos isolados e associados da terapia de reposição oral estrogênica e do exercício físico aeróbico nas respostas hemodinâmicas e neurais em mulheres no período pós-menopausa / Effects of estrogen replacement therapy in hemodinamic and neural responses to acute aerobic exercise in post-menopausal womenOneda, Bruna 22 February 2010 (has links)
A pós-menopausa é marcada por alterações fisiológicas hemodinâmicas e metabólicas. A terapia de reposição estrogênica é uma forma de amenizar as conseqüências da deficiência hormonal e o exercício físico contribui significativamente para a redução do risco cardiovascular. O objetivo desse estudo foi avaliar em mulheres pós-menopausadas os efeitos isolados e associados da terapia oral estrogênica (TRH) e do treinamento físico aeróbio (TF) nas respostas hemodinâmicas e neurais basais e durante os exercícios com handgrip. Quarenta e cinco mulheres (51±3 anos), histerectomizadas, com e sem ovários, saudáveis, realizaram uma sessão experimental e, posteriormente foram divididas em 4 grupos SED-PLA (n=11), SED-TRH (n=14), TF-PLA (n=12) e TF-TRH (n=8). Os grupos TRH e receberam valerato de estradiol 1mg/dia; PLA receberam placebo; TF, realizaram exercício aeróbio em cicloergômetro por 50 minutos, 3 vezes por semana e SED permaneceram sedentárias. Todas as voluntárias participaram de uma segunda sessão experimental após 6 meses de acompanhamento. Nas sessões experimentais foram avaliadas a atividade nervosa simpática periférica (ANSP - microneurografia), pressão arterial, freqüência cardíaca (FC - método oscilométrico Dixtal no membro inferior), fluxo sangüíneo do antebraço (FSA - pletismografia) em um período basal e durante exercícios estático e dinâmico com handgrip a 30% da força de contração máxima. Para análise estatística foi utilizada ANOVA. O TF isoladamente diminuiu ANSP de 40±7 a 34±4 impulsos/min, (P=0,01) e aumentou FSA de 1,92±0,96 a 2,65±1,34 ml(min.100ml), P=0,03 no período basal. TRH e TF associados reduziram a FC no período basal de 65±8 para 62±7 bpm (P=0,01) e durante o exercício estático e dinâmico com handgrip. A TRH de maneira isolada ou associada ao TF diminuiu as respostas de FC durante os exercícios estático e dinâmico com handgrip. Em conclusão, as intervenções de maneira isolada ou associada promovem alterações hemodinâmicas e neurais que podem contribuir para redução do risco cardiovascular de mulheres pós-menopausadas saudáveis. / The post-menopause is marked by physiological hemodynamic and metabolic changes. The estrogen replacement therapy is a way to reduce the consequences of hormone deficiency and physical exercise contributes significantly to the reduction of cardiovascular risk. The aim of this study was to evaluate in post-menopausal women the isolated and associated effects of oral estrogen therapy (TRH) and physical training (TF) in the neural and hemodynamic responses during baseline and \"handgrip\" exercises. Forty-five women (51 ± 3 years), hysterectomized, with or without ovaries, healthy, participated of an initial session and then they were divided into 4 groups SEDPLA (n = 11), SED-TRH (n = 14), TF-PLA (n = 12) and TF-TRH (n = 8). The TRH groups received estradiol valerate 1 mg / day; PLA placebo; TF, performed aerobic exercise on a cycle ergometer for 50 minutes, 3 times a week and SED remained sedentary. All subjects participated in a second experimental session after 6 months of follow-up. In the experimental sessions peripheral sympathetic nerve activity (ANSP - microneurography), blood pressure, heart rate (FC - oscillometry - Dixtal lower limb), forearm blood flow (FSA - plethysmography) were evaluated at the baseline period and during static and dynamic \"handgrip\" exercises at 30% of the maximum force. ANOVA was used for the statistica analysis. The TF alone decreased ANSP from 40 ± 7 to 34 ± 4 bursts/min, P = 0.01 and increased FSA 1.92 ± 0.96 to 2.65 ± 1.34 ml (min.100ml), P = 0.03 at the baseline. The association of TRH and TF reduced HR at the baseline from 65 ± 8 to 62 ± 7 bpm (P=0.01) and during exercise with static and dynamic \"handgrip\". HRT alone or associated with TF decreased the HR responses during static and dynamic \"handgrip exercises. In conclusion, the interventions alone or in an associated way promote neural and hemodynamic changes that may contribute to cardiovascular risk reduction in healthy postmenopausal women.
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IGF polymorphisms, lifestyle factors, and colorectal cancer risk /Morimoto, Libby Mitsue. January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Includes bibliographical references (leaves 101-113).
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Efeitos do treinamento resistido e da ovariectomia sobre marcadores de biogênese mitocondrial e capacidade oxidativa do músculo esquelético de ratas / Effects of resistance training and ovariectomy on mitochondrial biogenesis and oxidative capacity markers of skeletal muscle of ratsBarbosa, Marina Rodrigues 10 April 2015 (has links)
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Previous issue date: 2015-04-10 / Financiadora de Estudos e Projetos / The decrease of regulate the estrogen production that occurs at menopause is typically followed by increase of several deleterious changes in the skeletal muscle system. Menopause is mimicked experimentally by a technique called ovariectomy. The ovariectomy produces increased total body mass, changes in body composition and lipid profile, reduction in skeletal muscle (sarcopenia) and bone mineral mass (osteopenia). Mitochondria play a crucial role in a myriad of cellular processes including oxidative phosphorylation, biosynthetic pathways and programming of cell death. Alteration of mitochondrial biogenesis markers in ovariectomized rats and the effects of resistance training (RT) and estrogen replacement (RE) are unclear. Purpose: This study aimed to investigate the effects of Ovariectomy (Ovx), RT and ER on markers of mitochondrial biogenesis and protein expression related to oxidative capacity in the rat gastrocnemius pool. Methods: ER was performed using Silastic® capsules. During the 12-week RT, the animals climbed a ladder with weights attached to their tails. RT began simultaneously for all experimental groups. Gene expression was analysed by RT-PCR, and protein content was determined by western blotting. Results: The estrogen deficiency associated with Ovx decreased the gene expression of the mitochondrial biogenesis markers PGC-1α (~73%), NRF-1 (~44%), and TFAM (~53%) (p<0.05) and decreased the protein expression of phosphorylated AMPK, CREB and AKT, which are related to oxidative capacity, compared to the Sham-Sed group. RT increased PGC- 1α (~59%) and TFAM (~48%) expression compared to the Ovx-Sed group. The combination of RT and ER was superior to the Ovx-Sed and Ovx-RT treatments regarding the gastrocnemius muscle. Conclusions: This study showed that ovaries removal affects transcription factors that regulate mitochondrial biogenesis in skeletal muscle. According to our results and evidence from the literature, and estradiol levels of exercise appear to play an important role in the protection of mitochondrial dysfunction in skeletal muscle of rats. / Introdução: A diminuição da produção regular do estrógeno que ocorre na menopausa é tipicamente seguida pelo aumento de várias alterações deletérias no sistema musculoesquelético. A menopausa é mimetizada experimentalmente por uma técnica chamada ovariectomia. A ovariectomia produz aumento da massa corporal total, alterações na composição corporal e no perfil lipídico, redução da musculatura esquelética (sarcopenia) e da massa mineral óssea (osteopenia). As mitocôndrias desempenham papel crucial em uma miríade de processos celulares que incluem fosforilação oxidativa, vias de biossíntese e programação da morte celular. Alteração dos marcadores de biogênese mitocondrial em ratas ovariectomizadas, bem como os efeitos do treinamento resistido e reposição de estrógeno não são totalmente conhecidas. Objetivos: Investigar os efeitos da ovariectomia, do treinamento resistido e da reposição de estrógeno sobre a biogênese mitocondrial e capacidade oxidativa do músculo esquelético de ratas. Materiais e Métodos: A reposição de estrógeno foi realizada com cápsula Silastic. O treinamento resistido consistiu de 12 semanas em que os animais subiram uma escada com pesos atados às suas caudas. A expressão gênica foi analisada por RT-PCR e o conteúdo de proteína por Western Blotting. Resultados: A deficiência de estrogénio, associada à ovariectomia, reduziu a expressão gênica de marcadores de biogênese mitocondriais, tais como PGC-1α (~ 73%), NRF-1 (~ 44%), TFAM (~ 53%) (p <0,05) e o conteúdo de proteína relacionada à capacidade oxidativa, como AMPK, CREB e AKT quando comparado com grupo Sham-Sed. O treinamento resistido aumentou esses marcadores, tais como PGC-1α (~ 59%) e TFAM (~ 48%) em relação ao grupo Ovx-Sed. Conclusões: O presente estudo mostrou que a remoção dos ovários afeta fatores de transcrição que regulam a biogênese mitocondrial no músculo esquelético. De acordo com os nossos resultados e evidências da literatura, os níveis de estradiol e de exercício parecem desempenhar um papel importante na proteção da disfunção mitocondrial no músculo esquelético de ratas.
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Efeitos isolados e associados da terapia de reposição oral estrogênica e do exercício físico aeróbico nas respostas hemodinâmicas e neurais em mulheres no período pós-menopausa / Effects of estrogen replacement therapy in hemodinamic and neural responses to acute aerobic exercise in post-menopausal womenBruna Oneda 22 February 2010 (has links)
A pós-menopausa é marcada por alterações fisiológicas hemodinâmicas e metabólicas. A terapia de reposição estrogênica é uma forma de amenizar as conseqüências da deficiência hormonal e o exercício físico contribui significativamente para a redução do risco cardiovascular. O objetivo desse estudo foi avaliar em mulheres pós-menopausadas os efeitos isolados e associados da terapia oral estrogênica (TRH) e do treinamento físico aeróbio (TF) nas respostas hemodinâmicas e neurais basais e durante os exercícios com handgrip. Quarenta e cinco mulheres (51±3 anos), histerectomizadas, com e sem ovários, saudáveis, realizaram uma sessão experimental e, posteriormente foram divididas em 4 grupos SED-PLA (n=11), SED-TRH (n=14), TF-PLA (n=12) e TF-TRH (n=8). Os grupos TRH e receberam valerato de estradiol 1mg/dia; PLA receberam placebo; TF, realizaram exercício aeróbio em cicloergômetro por 50 minutos, 3 vezes por semana e SED permaneceram sedentárias. Todas as voluntárias participaram de uma segunda sessão experimental após 6 meses de acompanhamento. Nas sessões experimentais foram avaliadas a atividade nervosa simpática periférica (ANSP - microneurografia), pressão arterial, freqüência cardíaca (FC - método oscilométrico Dixtal no membro inferior), fluxo sangüíneo do antebraço (FSA - pletismografia) em um período basal e durante exercícios estático e dinâmico com handgrip a 30% da força de contração máxima. Para análise estatística foi utilizada ANOVA. O TF isoladamente diminuiu ANSP de 40±7 a 34±4 impulsos/min, (P=0,01) e aumentou FSA de 1,92±0,96 a 2,65±1,34 ml(min.100ml), P=0,03 no período basal. TRH e TF associados reduziram a FC no período basal de 65±8 para 62±7 bpm (P=0,01) e durante o exercício estático e dinâmico com handgrip. A TRH de maneira isolada ou associada ao TF diminuiu as respostas de FC durante os exercícios estático e dinâmico com handgrip. Em conclusão, as intervenções de maneira isolada ou associada promovem alterações hemodinâmicas e neurais que podem contribuir para redução do risco cardiovascular de mulheres pós-menopausadas saudáveis. / The post-menopause is marked by physiological hemodynamic and metabolic changes. The estrogen replacement therapy is a way to reduce the consequences of hormone deficiency and physical exercise contributes significantly to the reduction of cardiovascular risk. The aim of this study was to evaluate in post-menopausal women the isolated and associated effects of oral estrogen therapy (TRH) and physical training (TF) in the neural and hemodynamic responses during baseline and \"handgrip\" exercises. Forty-five women (51 ± 3 years), hysterectomized, with or without ovaries, healthy, participated of an initial session and then they were divided into 4 groups SEDPLA (n = 11), SED-TRH (n = 14), TF-PLA (n = 12) and TF-TRH (n = 8). The TRH groups received estradiol valerate 1 mg / day; PLA placebo; TF, performed aerobic exercise on a cycle ergometer for 50 minutes, 3 times a week and SED remained sedentary. All subjects participated in a second experimental session after 6 months of follow-up. In the experimental sessions peripheral sympathetic nerve activity (ANSP - microneurography), blood pressure, heart rate (FC - oscillometry - Dixtal lower limb), forearm blood flow (FSA - plethysmography) were evaluated at the baseline period and during static and dynamic \"handgrip\" exercises at 30% of the maximum force. ANOVA was used for the statistica analysis. The TF alone decreased ANSP from 40 ± 7 to 34 ± 4 bursts/min, P = 0.01 and increased FSA 1.92 ± 0.96 to 2.65 ± 1.34 ml (min.100ml), P = 0.03 at the baseline. The association of TRH and TF reduced HR at the baseline from 65 ± 8 to 62 ± 7 bpm (P=0.01) and during exercise with static and dynamic \"handgrip\". HRT alone or associated with TF decreased the HR responses during static and dynamic \"handgrip exercises. In conclusion, the interventions alone or in an associated way promote neural and hemodynamic changes that may contribute to cardiovascular risk reduction in healthy postmenopausal women.
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Efeitos da terapia de reposição estrogênica nas respostas hemodinâmicas e neurais ao exercício físico agudo em mulheres no período pós-menopausa / Effects of estrogen replacement therapy in hemodinamic and neural responses to acute aerobic exercise in post-menopausal womenBruna Oneda 17 April 2006 (has links)
A pós-menopausa é marcada por alterações fisiológicas hemodinâmicas e metabólicas. A terapia de reposição estrogênica é uma forma de amenizar as conseqüências da deficiência hormonal e o exercício físico contribui significativamente para a redução do risco cardiovascular. O objetivo desse estudo foi avaliar em mulheres pós-menopausadas os efeitos isolados e associados da terapia oral estrogênica (TRH) e do treinamento físico aeróbio (TF) nas respostas hemodinâmicas e neurais basais e durante os exercícios com handgrip. Quarenta e cinco mulheres (51±3 anos), histerectomizadas, com e sem ovários, saudáveis, realizaram uma sessão experimental e, posteriormente foram divididas em 4 grupos SED-PLA (n=11), SED-TRH (n=14), TF-PLA (n=12) e TF-TRH (n=8). Os grupos TRH e receberam valerato de estradiol 1mg/dia; PLA receberam placebo; TF, realizaram exercício aeróbio em cicloergômetro por 50 minutos, 3 vezes por semana e SED permaneceram sedentárias. Todas as voluntárias participaram de uma segunda sessão experimental após 6 meses de acompanhamento. Nas sessões experimentais foram avaliadas a atividade nervosa simpática periférica (ANSP - microneurografia), pressão arterial, freqüência cardíaca (FC - método oscilométrico Dixtal no membro inferior), fluxo sangüíneo do antebraço (FSA - pletismografia) em um período basal e durante exercícios estático e dinâmico com handgrip a 30% da força de contração máxima. Para análise estatística foi utilizada ANOVA. O TF isoladamente diminuiu ANSP de 40±7 a 34±4 impulsos/min, (P=0,01) e aumentou FSA de 1,92±0,96 a 2,65±1,34 ml(min.100ml), P=0,03 no período basal. TRH e TF associados reduziram a FC no período basal de 65±8 para 62±7 bpm (P=0,01) e durante o exercício estático e dinâmico com handgrip. A TRH de maneira isolada ou associada ao TF diminuiu as respostas de FC durante os exercícios estático e dinâmico com handgrip. Em conclusão, as intervenções de maneira isolada ou associada promovem alterações hemodinâmicas e neurais que podem contribuir para redução do risco cardiovascular de mulheres pós-menopausadas saudáveis. / The post-menopause is marked by physiological hemodynamic and metabolic changes. The estrogen replacement therapy is a way to reduce the consequences of hormone deficiency and physical exercise contributes significantly to the reduction of cardiovascular risk. The aim of this study was to evaluate in post-menopausal women the isolated and associated effects of oral estrogen therapy (TRH) and physical training (TF) in the neural and hemodynamic responses during baseline and \"handgrip\" exercises. Forty-five women (51 ± 3 years), hysterectomized, with or without ovaries, healthy, participated of an initial session and then they were divided into 4 groups SEDPLA (n = 11), SED-TRH (n = 14), TF-PLA (n = 12) and TF-TRH (n = 8). The TRH groups received estradiol valerate 1 mg / day; PLA placebo; TF, performed aerobic exercise on a cycle ergometer for 50 minutes, 3 times a week and SED remained sedentary. All subjects participated in a second experimental session after 6 months of follow-up. In the experimental sessions peripheral sympathetic nerve activity (ANSP - microneurography), blood pressure, heart rate (FC - oscillometry - Dixtal lower limb), forearm blood flow (FSA - plethysmography) were evaluated at the baseline period and during static and dynamic \"handgrip\" exercises at 30% of the maximum force. ANOVA was used for the statistica analysis. The TF alone decreased ANSP from 40 ± 7 to 34 ± 4 bursts/min, P = 0.01 and increased FSA 1.92 ± 0.96 to 2.65 ± 1.34 ml (min.100ml), P = 0.03 at the baseline. The association of TRH and TF reduced HR at the baseline from 65 ± 8 to 62 ± 7 bpm (P=0.01) and during exercise with static and dynamic \"handgrip\". HRT alone or associated with TF decreased the HR responses during static and dynamic \"handgrip exercises. In conclusion, the interventions alone or in an associated way promote neural and hemodynamic changes that may contribute to cardiovascular risk reduction in healthy postmenopausal women.
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Ghrelin and atherosclerosis:human, experimental animal and cell culture studiesKellokoski, E. (Eija) 20 October 2009 (has links)
Abstract
Atherosclerosis is the major cause of cardiovascular diseases and the leading cause of death globally. Atherosclerosis is a complex, chronic disease characterized by lipid accumulation and inflammation within the intima layer of vessel wall. Novel biomarkers and therapeutics are still being sought to provide both better diagnosis and treatment. Ghrelin represents an attractive target for studies into atherosclerosis. Ghrelin is a gastric peptide hormone, which has multiple functions, including regulation of appetite and energy metabolism. Emerging evidence suggests that it may also have a role in the cardiovascular and immune systems.
The aim of the present study was to explore the role of ghrelin in atherosclerosis. The specific aims were 1) to investigate the association between the plasma ghrelin level and early atherosclerosis as determined by carotid artery intima media thickness (IMT) in a large (n = 1024) cross-sectional population-based study of middle-aged subjects, 2) to measure the associations between plasma ghrelin levels and already established risk factors of atherosclerosis in human subjects, 3) to assess the effects of ghrelin on atherogenesis in vitro by analyzing monocyte adhesion to endothelial cells, oxidized low density lipoprotein (LDL) binding and acetylated LDL uptake using macrophages, and 4) to study the influence of ghrelin on atherosclerosis using ghrelin vaccination in a mouse model of atherosclerosis.
Plasma total ghrelin levels were positively associated with carotid IMT in male subjects. Association studies demonstrated plasma ghrelin levels to be negatively associated with total and LDL cholesterol, and triglyceride concentrations as well as with body mass index (BMI), and positively assocated with high density lipoprotein (HDL) cholesterol concentration in postmenopausal women and in a population-based study. In addition, estrogen increased plasma acylated ghrelin levels in postmenopausal women. Cell culture studies demonstrated that ghrelin could increase the binding of oxidized LDL and monocytes to endothelial cells. Interestingly, when endothelial cells were stimulated with tumor necrosis factor α (TNFα), then ghrelin prevented monocyte adhesion. The study with LDL receptor knockout mice, revealed that ghrelin vaccination could increase plasma ghrelin levels but had no effects on the development of atherosclerosis. However, the plasma MCP-1 level decreased in mice immunized with ghrelin vaccine. In conclusion, these studies suggest that ghrelin has modulatory functions in the vascular system and atherogenesis though the effect may not be as dominant as that of the known traditional risk factors. Whether this effect of ghrelin is positive or negative in atherogenesis will be clarified in further studies. / Tiivistelmä
Sydän- ja verisuonitaudit ovat suurin kuolinsyy niin Suomessa kuin useimmissa länsimaissakin. Näiden sairauksien taustalla on yleensä valtimonkovettumatauti eli ateroskleroosi, joka voi kliinisesti ilmentyä mm. sepelvaltimotautina, aivoveritulppana ja laskimotautina. Ateroskleroosissa tulehdussoluja ja kolesterolia kertyy verisuonen seinämään muodostaen ahtauman eli ateroomaplakin valtimoon. Valtimonkovettumataudin riskitekijäitä tunnetaan jo hyvin, mutta uusia tautia ennustavia merkkiaineita sekä hoitomuotoja tarvitaan yhä. Greliini on mahalaukusta eritettävä peptidihormoni, joka osallistuu elimistössä mm. ruokahalun, energiametabolian, tulehdustekijöiden sekä sydän- ja verenkiertoelimistön toiminnan säätelyyn.
Tämän työn tavoitteena oli tutkia greliinin yhteyttä ihmisen valtimonkovettumatautiin. Tutkimus toteutettiin käyttämällä kahta eri potilasaineistoa, soluviljelykokeita sekä valtimonkovettumataudin hiirimallia. Laajassa väestöpohjaisessa potilasaineistossa tutkittiin veren greliinipitoisuuden yhteyttä kaulavaltimon seinämän paksuuteen, jota pidetään valtimonkovettumista kuvaavana tekijänä. Veren greliinipitoisuuden yhteyttä valtimonkovettumataudin tunnettuihin riskitekijöihin tutkittiin myös laajassa potilasaineistossa sekä vaihdevuosi-ikäisillä naisilla, joille annettiin estrogeenikorvaushoitoa. Solukokeilla selvitettiin greliinin vaikutusta tärkeisiin valtimonkovettumataudin syntyvaiheisiin käyttäen monosyytti-, endoteelisolu- sekä makrofaagi-soluviljelmiä. Greliinin vaikutusta ateroskleroosiin in vivo selvitettiin rokottamalla LDL-reseptoripuutteiset hiiret greliini-rokotteella.
Tutkimuksessa havaittiin yhteys veren korkean greliinipitoisuuden ja kaulavaltimon seinämän paksuuden välillä miehillä laajassa potilasaineistossa (n = 1024). Tulosta tukivat soluilla tehdyt kokeet, joissa greliini lisäsi hapettuneen LDL:n sitoutumista makrofaageihin sekä monosyyttien tarttumista endoteelisolujen pinnalle. Greliinin vaikutukset monosyyttien tarttumiseen endoteelisolujen pinnalle olivat päinvastaiset silloin, kun endoteelisolut käsiteltiin tulehdusta stimuloivalla tekijällä. Matalat veren greliinipitoisuudet olivat myös yhteydessä korkeisiin LDL-kolesteroli- ja triglyseriditasoihin sekä painoindeksiin ja matalaan HDL-kolesterolitasoon potilasaineistoissa. Estrogeeni nosti veren greliinipitoisuutta vaihdevuosi-ikäisillä naisilla. Greliinirokote ei vaikuttanut ateroskleroosin kehittymiseen hiirimallissa. Tutkimustulosten perusteella greliinillä näyttäisi osallistuvan valtimonkovettumataudin kehitykseen, vaikkakin sen vaikutus on pienempi kuin aiemmin tunnetuilla taudin riskitekijöillä.
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Genetic and epidemiological studies on the role of adiponectin and PTP1B in the metabolic syndromeSantaniemi, M. (Merja) 21 May 2010 (has links)
Abstract
The metabolic syndrome is a cluster of components predisposing to type 2 diabetes and cardiovascular disease. Abdominal obesity and insulin resistance seem to be central in the metabolic syndrome, although no unifying pathophysiological mechanism is available. The aim of this thesis was to determine out how the variation in PTP1B and adiponectin gene as well as variations in the plasma adiponectin concentration contribute to the risk of obesity related diseases.
PTP1B is a negative regulator of insulin signalling and therefore considered a candidate gene for type 2 diabetes. In the first study, it was found that three PTP1B polymorphisms studied have not strong impact on type 2 diabetes. However, one SNP may be slightly protective against type 2 diabetes, since it was more frequent in the healthy group compared to group of patients with type 2 diabetes. Another SNP was associated with body mass index (BMI). The combination of certain alleles of PTP1B and LEPR (leptin receptor) genes was also associated to BMI.
Adiponectin is an adipocytokine expressed in adipose tissue. It has insulin sensitizing effects in liver and muscle and it has also beneficial effects on cardiovascular health. In the second study, the contribution of adiponectin genotypes with obesity-related phenotypes was studied. In Caucasians, the carriers of rare allele of Tyr111His polymorphism were more insulin resistant and at a higher risk of developing type 2 diabetes. In African-Americans, other polymorphisms were associated with BMI and lipids. Thus, the effects of polymorphisms on obesity related phenotypes seemed to be different between ethnic groups.
Plasma adiponectin levels were measured from different study groups. In the third study, it was found out that low plasma adiponectin levels associated with different components of the metabolic syndrome and there was a trend towards reductions in adiponectin with an increasing number of components. Fourth study indicated that baseline low adiponectin level associated with a more than 2-fold risk for developing impaired glucose tolerance or type 2 diabetes in the follow-up study of normoglycemic middle-aged Finnish subjects. In the fifth study, plasma adiponectin levels were measured from postmenopausal women receiving estrogen replacement therapy. We observed a reduction in adiponectin levels in women having peroral estradiol which could be part of the "early harm" profile on cardiovascular risk factors of the peroral estrogen replacement therapy detected in clinical trials.
These studies further strengthen the role of plasma adiponectin in the obesity related diseases and bring new information of polymorphisms in the adiponectin and PTP1B genes in different populations. / Tiivistelmä
Metabolinen oireyhtymä on kertymä tekijöitä, jotka altistavat tyypin 2 diabetekselle ja sydän- ja verisuonitaudeille. Keskivartalolihavuus ja insuliiniresistenssi, eli insuliinin heikentynyt teho, vaikuttavat olevan keskeisiä metabolisessa oireyhtymässä. Kuitenkaan taustalla olevaa syntymekanismia ei täysin tunneta. Väitöskirjatyön tavoitteena oli tutkia PTP1B- ja adiponektiinigeenin muuntelun sekä plasman adiponektiinitason yhteyttä metaboliseen oireyhtymään, sen osatekijöihin ja seurauksiin.
PTP1B on insuliinin toimintaa soluissa estävä molekyyli. Ensimmäisessä tutkimuksessa havaittiin että kolme tutkittua PTP1B-geenin nukleotidimuutosta eivät ole vahvasti yhteydessä tyypin 2 diabetekseen. Eräs nukleotidimuutos saattaisi olla lievästi suojaava tyypin 2 diabetesta vastaan, sillä se oli yleisempi terveillä kuin tyypin 2 diabetesta sairastavilla. PTP1B:n ja leptiinireseptorigeenin eräiden alleelien yhdistelmä oli yhteydessä painoindeksiin.
Adiponektiini on rasvakudoksen erittämä hormoni, jolla on suotuisia, insuliinin vaikutusta edesauttavia vaikutuksia elimistössä sekä edullisia vaikutuksia verenkiertoelimistössä. Toisessa työssä havaittiin että Amerikan valkoihoisilla, joilla oli eräs harvinainen adiponektiinigeenin alleeli (Tyr111His), oli heikompi insuliinin teho kuin henkilöillä joilla ei ollut kyseistä muutosta. Tämä alleeli oli yleisempi suomalaisilla tyypin 2 diabetesta sairastavilla kuin terveillä, mikä saattaa tarkoittaa että se liittyy suurentuneeseen riskiin tyypin 2 diabetekselle. Afroamerikkalaisilla taas toiset nukleotidimuutokset olivat yhteydessä lihavuuteen ja plasman rasva-arvoihin.
Adiponektiinin pitoisuutta plasmassa mitattiin erilaisissa aineistoissa. Kolmannessa tutkimuksessa havaittiin, että matala pitoisuus oli yhteydessä metabolisen oireyhtymän eri osatekijöihin ja pitoisuus oli sitä matalampi, mitä enemmän osatekijöitä henkilöllä on. Neljännessä tutkimuksessa havaittiin että matala plasman adiponektiinipitoisuus oli yhteydessä suurentuneeseen riskiin saada huonontunut glukoosin sietokyky tai tyypin 2 diabetes tulevaisuudessa. Viidennessä tutkimuksessa adiponektiinitaso määritettiin naisilta jotka olivat ohittaneet vaihdevuodet ja saivat estrogeenikorvaushoitoa. Havaittiin että plasman adiponektiinitaso laski niillä naisilla, jotka saivat korvaushoitoa suun kautta. Tämä saattaisi osittain selittää suun kautta annettavan estrogeenikorvaushoidon epäedullista vaikutusta sydän ja -verisuonitautien riskitekijöihin.
Tutkimus vahvistaa edelleen adiponektiinin merkitystä lihavuuteen liittyvissä sairauksissa ja tuo uutta tietoa adiponektiini- ja PTP1B-geenien muuntelun merkityksestä eri väestöissä.
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