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  • 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.
131

Efeito de hipolipemiantes sobre a expressão de genes envolvidos no transporte reverso do colesterol / Statin effects on expression of genes involved in reverse cholesterol transport

Genvigir, Fabiana Dalla Vecchia 08 September 2011 (has links)
A eficácia das estatinas em reduzir o risco de eventos coronarianos não é completamente explicada por seus efeitos em diminuir colesterol de lipoproteína de baixa densidade (LDL-C). Um dos seus efeitos adicionais pode ser decorrente da modificação na concentração de lipoproteína de alta densidade (HDL), reconhecida como ateroprotetora, principalmente por seu papel no transporte reverso do colesterol (TRC). Os transportadores de membrana do tipo ATP-binding cassette, ABCA1 e ABCG1, e o scavenger receptor BI (SRBI) são proteínas importantes envolvidas no TRC e seus genes são regulados por vários fatores de transcrição, entre eles os liver-x-receptors (LXRs). Com a finalidade de avaliarmos os efeitos dos hipolipemiantes sobre expressão dos transportadores ABC e do receptor SRBI, a expressão de RNAm do ABCA1, ABCG1, SCARB1, NR1H3 (LXR&#945;) e NR1H2 (LRX&#946;) foi avaliada por PCR em tempo real em células das linhagens HepG2 (origem hepática) e Caco-2 (origem intestinal) tratadas com atorvastatina ou sinvastatina (10 µM) e/ou ezetimiba (até 5 µM) por até 24 horas. Além disso, a expressão desses genes também foi avaliada em células mononucleares do sangue periférico (CMSP) de 50 pacientes normolipidêmicos (NL) e 71 hipercolesterolêmicos (HC) tratados com atorvastatina (10mg/dia/4semanas, n=48) ou sinvastatina e/ou ezetimiba (10mg/dia/4 ou 8 semanas, n=23). A possível associação entre os polimorfismos ABCA1 C-14T e R219K e a expressão de RNAm em CMSP também foi avaliada por PCR-RFLP. O SCARB1 foi o gene mais expresso nas células HepG2 e Caco-2, seguido por NR1H2, NR1H3, ABCG1 e ABCA1 em HepG2 ou por ABCA1 e ABCG1 em Caco-2. O tratamento com estatinas (1 ou 10 µM) ou ezetimiba (5 µM), por 12 ou 24 horas, aumentou a expressão de RNAm do ABCG1, mas não de ABCA1 e SCARB1, em células HepG2. Ainda nesta linhagem, o aumento na transcrição dos genes NR1H2 e NR1H3 foi observado somente com a maior concentração de atorvastatina (10 µM) e, ao contrário, o tratamento com ezetimiba causou redução na transcrição de NR1H2, sem alteração de NR1H3. Em células Caco-2, o tratamento com atorvastatina ou sinvastatina por 12 ou 24 horas reduziu a quantidade do transcrito ABCA1 e não alterou a expressão do SCARB1 e do ABCG1, embora, para este último, tenha havido uma tendência à diminuição da expressão após tratamento com sinvastatina (p=0,07). Após tratamento com ezetimiba isolada (até 5 µM) nenhuma alteração de expressão de RNAm foi observada em células Caco-2; no entanto, após 24 horas de tratamento com sinvastatina e ezetimiba, foi reduzida a taxa de transcrição de ABCA1 e ABCG1, mas não de SCARB1. Ao contrário das linhagens celulares, em CMSP os genes NR1H2 e ABCG1 foram os mais expressos, seguidos pelos genes SCARB1 e ABCA1 e, finalmente, pelo NR1H3. Indivíduos HC tiveram maior expressão basal de NR1H2 e NR1H3, mas não de outros genes, quando comparados aos NL (p<0,05). Além disso, nos indivíduos HC, a expressão basal de ABCA1 foi maior em portadores do alelo -14T do polimorfismo ABCA1 -14C>T quando comparados aos portadores do genótipo -14CC (p=0,034). O tratamento com estatinas, com ezetimiba ou com a terapia combinada diminuiu a transcrição de ABCA1 e ABCG1. Para o SCARB1, NR1H2 e NR1H3, nenhuma alteração de expressão de RNAm em CMSP foi detectada após os tratamentos in vivo. Após todas as fases de tratamento, ABCA1 e ABCG1 e também NR1H2 e NR1H3 foram significativamente correlacionados entre si, mas nenhuma correlação com perfil lipídico sérico foi relevante. Coletivamente, esses resultados dão indícios de que os hipolipemiantes analisados (estatinas e ezetimiba) têm um importante papel na regulação da expressão de genes envolvidos no transporte reverso do colesterol e sugerem a existência de regulação tecido-específica para os dois transportadores ABC. Além disso, o efeito das estatinas ou da ezetimiba sobre a expressão do ABCA1, do ABCG1 ou do SCARB1 não sofreu influencia de alterações diretas da transcrição dos LXRs. / The efficacy of statins in reducing the risk of coronary events is not completely explained by their effects in decreasing cholesterol low-density lipoprotein (LDL-C). One of their additional effects may result from the change in concentration of high-density lipoprotein (HDL), recognized as atheroprotective, mainly for the role in reverse cholesterol transport (RCT). The membrane transporters, as ATP-binding cassette, ABCA1 and ABCG1, and scavenger receptor BI (SRBI) are important proteins involved in the RCT and their genes are regulated by various transcription factors, including the liver-X-receptors (LXRs) . In order to evaluate the effects of lipid lowering on expression of ABC transporters and SRBI receptor, the mRNA expression of ABCA1, ABCG1, SCARB1, NR1H3 (LXR&#945;) and NR1H2 (LRX&#946;) was assessed by real time PCR in HepG2 (hepatic origin) and Caco-2 (intestinal origin) cells treated with atorvastatin or simvastatin (10 µM) and/or ezetimibe (up to 5 µM) for 24 hours. Furthermore, the expression of these genes was evaluated in peripheral blood mononuclear cells (PBMC) of 50 normolipidemic (NL) and 71 hypercholesterolemic (HC) patients treated with atorvastatin (10mg/d/4 weeks, n = 48) or simvastatin and/or ezetimibe (10mg/d/4 or 8 weeks, n = 23). The possible association between ABCA1 C-14T and R219K polymorphisms and mRNA expression in PBMC was also evaluated by PCR-RFLP. SCARB1 was the most expressed in HepG2 and Caco-2 cells, followed by NR1H2, NR1H3, ABCG1 and ABCA1 in HepG2 or by ABCG1 and ABCA1 in Caco-2. The treatment with statins (1 or 10 µM) or ezetimibe (5 µM) for 12 or 24 hours, increased mRNA expression of ABCG1 but not ABCA1 and SCARB1 in HepG2 cells. Moreover, in HepG2 cells, atorvastatin also upregulated NR1H2 and NR1H3 only at 10.0 &#181;M, meanwhile ezetimibe downregulated NR1H2 but did not change NR1H3 expression. In Caco-2 cells, atorvastatin or simvastatin treatment for 12 or 24 hours reduced the amount of ABCA1 transcript and did not alter the ABCG1 and SCARB1 expressions, despite the tendency to decrease ABCG1 mRNA expression after simvastatin treatment (p = 0.07). After treatment with ezetimibe alone (up to 5 &#181;M) no change in mRNA expression was observed in Caco-2 cells; however, after 24 hours- simvastatin and ezetimibe treatments decreased the transcription of ABCA1 and ABCG1, but not of SCARB1. Unlike cell lines, in PBMC, NR1H2 and ABCG1 were the most expressed, followed by SCARB1 and ABCA1 and finally by the NR1H3. HC patients showed higher NR1H2 and NR1H3 basal expressions, but not of other genes, compared to NL (p <0.05). Moreover, in HC individuals, the ABCA1 basal expression was higher in individuals carrying -14T allele of -14C> T polymorphism when compared with -14CC carriers (p = 0.034). Treatment with statins, ezetimibe, or combined therapy downregulated ABCA1 and ABCG1 expression. For SCARB1, NR1H2 and NR1H3, no change in mRNA expression in PBMC was detected after treatments. After all phases of treatment, ABCA1 and ABCG1 as well as NR1H2 and NR1H3 were significantly correlated, but no correlation with serum lipid profile was relevant. Collectively, these results provide evidences that the lipid lowering (statins and ezetimibe) have an important role in mRNA expression regulation of genes involved in reverse cholesterol transport and suggest the existence of tissue-specific regulation for the ABC transporters. Furthermore, the effect of statins or ezetimibe on ABCA1, ABCG1 or SCARB1 expression was not directly influenced by changes of LXR transcription.
132

Efeitos da adição de sinvastatina ao enalapril em indivíduos hipertensos com níveis de colesterol limítrofe e disfunção diastólica: um estudo aleatorizado, controlado, duplo-cego, com ecocardiograma e Doppler tecidual de repouso e estresse / Effect of the addition of simvastatin to enalapril in hypertensive individuals with average cholesterol levels and diastolic dysfunction: a randomized, placebo-controlled, double-blind trial, with ecochardiography and tissue Doppler of rest and stres

Beck, Adenalva Lima de Souza 07 May 2010 (has links)
Introdução: Disfunção diastólica (DD) e diminuição da reserva contrátil do ventrículo esquerdo aumentam o risco cardiovascular de pacientes com hipertensão arterial sistêmica. As estatinas, pelos seus benefícios sobre a fibrose miocárdica, podem melhorar a função diastólica ou reserva contrátil de forma mais eficaz que inibidores da enzima de conversão da angiotensina (I-ECA) nesses pacientes. Objetivos: Investigar o efeito aditivo da estatina ao I-ECA na função diastólica e reserva contrátil de hipertensos com níveis de colesterol limítrofe. Métodos: Pacientes hipertensos com DD e LDL-colesterol < 160mg/dl submeteram-se a uma fase experimental para atingir pressão arterial sistólica (PAS) < 135mmHg e pressão arterial diastólica (PAD) < 85mmHg com enalapril ou enalapril e hidroclorotiazida. Quatro semanas após atingir o objetivo terapêutico, 55 pacientes foram aleatorizados para receber 80mg de sinvastatina (n = 27) ou placebo (n = 28) por um período de 20 semanas. Ecocardiograma de repouso e de estresse com dobutamina foram realizados antes e após o tratamento. O volume máximo do átrio esquerdo (VAE) foi medido pelo método biplanar de Simpson. Foram obtidas as velocidades de Doppler convencional e tecidual (DT) na diástole precoce (E, e) e diástole tardia (A, a) em repouso e durante estresse. As velocidades de DT foram a média dos 4 anéis mitrais basais. A reserva contrátil e a reserva diastólica do VE foram calculadas. A PA foi aferida mensalmente em consultório e o perfil lipídico foi dosado a cada 2 meses. Resultados: Após 20 semanas, a sinvastatina reduziu significativamente a PAS (-4±2mmHg; p=0,02), os níveis de colesterol total (-47±6 para estatina versus 6,2±5mg/dl para placebo; p<0,0001), LDL-colesterol (-41±5 para estatina versus 9,6±4mg/dl para placebo; p<0,0001) e triglicérides (-22,8±11,1 para estatina versus 15,3±8,3mg/dl para placebo; p<0,01). A razão E/A aumentou significativamente no grupo estatina (1,00±0,05 para 1,18±0,06 para estatina versus 1,06±0,05 para 1,06±0,04 para placebo; p=0,03), ao mesmo tempo em que o VAE reduziu significativamente neste grupo quando comparado ao placebo (24,5±0,9 para 21,1±0,8ml/m² para estatina versus 23,5±1,0 para 23,2±1,1ml/m² para placebo; p=0,048). A velocidade de e aumentou marginalmente no grupo estatina (9,6±0,6 para 10,2±0,5cm/s; p=0,05), mas sem diferença entre os grupos. A reserva contrátil aumentou significativamente em ambos os grupos (0,53±0,03 para 0,66± 0,05, p=0,009 para placebo versus 0,58±0,05 para 0,70±0,05, p=0,02 para estatina). Não houve correlação entre razão E/A, VAE e mudanças na pressão arterial ou níveis de colesterol. Houve uma moderada correlação positiva entre pressão arterial e LDL-colesterol (r=0,54; p=0,004). Conclusões: 1) A adição da sinvastatina ao enalapril melhora parâmetros de função diastólica em pacientes hipertensos com níveis de colesterol limítrofe, sendo este efeito independente da redução da pressão arterial ou do colesterol. 2) A PAS reduz com a sinvastatina, sendo esta redução correlacionada à redução do LDL-colesterol. 3) A reserva contrátil melhora com o tratamento com enalapril independente do uso da sinvastatina / Background: Diastolic dysfunction (DD) and decreased contractile reserve associated with hypertension are a surrogate for increased cardiovascular risk. Statins have experimental benefits on myocardial fibrosis, and could improve diastolic function or contractile reserve to a greater extend than ACE-inhibitors in hypertension. Objectives: Test in a double-blinded, placebo-controlled randomized study the effects of simvastatin added to enalapril treatment on DD and contractile reserve in hypertensive patients with average cholesterol levels. Methods: Hypertensive patients with DD and LDL-cholesterol < 160mg/dl underwent a run-in phase to achieve a systolic blood pressure (SBP) < 135mmHg and diastolic blood pressure (DBP) < 85mmHg with enalapril. Hydrochlorothiazide was added when need to achieve SBP or DBP control. Four weeks after reaching the optimum anti-hypertensive regimen, 55 patients were randomized to receive 80mg simvastatin (n = 27) or placebo (n = 28) for a period of 20 weeks. Transthoracic echocardiograms at rest and with dobutamine stress were performed before and after treatment. Left atrial volume (LAV) was measured by biplane modified Simpsons rule. Conventional mitral Doppler velocities were obtained at early diastole (E), late diastole (A) and E/A ratio was calculated, also Tissue Doppler velocities from mitral annulus (average from 4 basal walls) were measured at early diastole (e), late diastole (a) and systole (s); both at rest and during stress. The contractile and diastolic reserves were calculated at low dose of dobutamine stress. Blood pressure was measured monthly and lipid profile was analyzed every two months. Results: After 20 weeks, statin group showed a significant decrease in SBP (-4±2mmHg; p=0.02), total cholesterol (-47±6 for statin and 6.2±5mg/dl for placebo; p<0,0001), LDL-cholesterol (-41±5 for statin and 9.6±4mg/dl for placebo; p<0,0001) and tryglicerides levels (-22.8±11 for statin and 15.3±8mg/dl for placebo; p<0,01). E/A ratio increased significantly in statin group (1±0.05 to 1.18±0.06 for statin and 1,06±0,05 to 1,06±0,04 for placebo; p=0.03) at the same time that left atrial volume decreased (24.5±0.9 to 21.1±0.8ml/m² for statin and 23.5±1.0 to 23.2±1.1ml/m² for placebo; p=0.048). Moreover, e velocity had a trend to increase in statin (9.6±0.6 to 10.2±0.5cm/s; p=0.05) but there was no difference from placebo. Contractile reserve increased equally in both groups at lower dose of dobutamine (0.53±0.03 to 0.66±0.05, p=0.009 for placebo; 0.58±0.05 to 0.70±0.05, p=0.02 for statin). There was no correlation between E/A ratio, LAV and changes in blood pressure or cholesterol levels. There was a positive moderate correlation of blood pressure and LDL-cholesterol changes (r=0.54; p=0.004). Conclusions: 1) Simvastatin added to enalapril treatment in hypertensive patients with average cholesterol levels improves parameters of diastolic function independent of blood pressure or cholesterol changes. 2) Simvastatin decrease in SBP is correlated with LDL-cholesterol decrease. 3) Contractile reserve improves with hypertensive treatment irrespective to treatment with simvastatin
133

O efeito das estatinas na prevenção de complicações pós-operatórias em pacientes adultos submetidos a cirurgias cardíaca e não-cardíaca: revisão sistemática e metanálise com análise sequencial de estudos randomizados / Perioperative statin therapy in cardiac and non-cardiac surgery: a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials

Carvalho e Silva, Carolina Maria Pinto Domingues de 03 July 2018 (has links)
Introdução: Estudos anteriores sugerem possível benefício do uso perioperatório das estatinas para redução de eventos cardiovasculares pósoperatórios. Metanálise previamente publicada demonstra que as estatinas reduzem mortalidade e infarto perioperatório em pacientes submetidos a cirurgia não-cardíaca. Entretanto, novas evidências em cirurgia cardíaca sugerem efeitos neutros ou mesmo deletérios das estatinas, sendo que metanálise recente demonstrou aumento da incidência de insuficiência renal aguda e tendência a maior mortalidade pós-operatória. Devido aos resultados conflitantes e escassez de evidências definitivas, foi realizada uma revisão sistemática e metanálise de estudos randomizados para avaliar os efeitos do uso perioperatório das estatinas em cirurgia cardíaca e nãocardíaca. Objetivo: Avaliar em pacientes adultos submetidos à cirurgia cardíaca e não-cardíaca a associação entre o uso perioperatório de estatinas e a incidência pós-operatória de infarto agudo do miocárdio, acidente vascular cerebral, insuficiência renal aguda e mortalidade. Metodologia: As bases de dados Pubmed, EMBASE e Cochrane foram avaliadas por 2 pesquisadores independentes até 1º de maio de 2018 para busca de artigos apropriados. Foram incluídos estudos randomizados que avaliaram o uso perioperatório de estatinas comparadas a placebo ou a nenhum tratamento em pacientes submetidos a cirurgia cardíaca e nãocardíaca. Foram calculados o risco relativo (RR) ou razão de chances (odds ratio, OR) e intervalo de confiança 95% (IC 95%) por meio de metanálise de efeitos fixos. Foi realizada a análise sequencial dos estudos (trial sequential analysis, TSA) para quantificar a confiabilidade estatística dos dados. A metodologia Cochrane foi utilizada. Os desfechos primários foram definidos como infarto agudo do miocárdio, acidente vascular cerebral, insuficiência renal aguda e mortalidade no período pós-operatório. Resultados: Foram incluídos 35 estudos randomizados totalizando 8200 pacientes. O uso de estatina comparado ao controle foi associado a menor incidência de infarto em pacientes submetidos a cirurgia não-cardíaca (OR=0,44 [IC 95%, 0,30 a 0,64], p < 0,0001), mas não em pacientes submetidos a cirurgia cardíaca (OR=0,93 [IC 95%, 0,70 a 1,24], p=0,61). O uso da estatina foi associado a maior incidência de insuficiência renal aguda em cirurgia cardíaca (RR=1,15 [IC 95%, 1,00 a 1,31], p=0,05), mas não em cirurgia não-cardíaca (RR=1,52 [IC 95%, 0,71 a 3,26], p=0,28). Não foi observado impacto do uso das estatinas na ocorrência de acidente vascular cerebral e mortalidade em ambos os grupos cirúrgicos. No entanto, a análise dos estudos com baixo risco de viés em cirurgia cardíaca demonstrou maior mortalidade com o uso de estatinas comparadas a placebo (OR=3,71 [IC 95%, 1,03 a 13,34], p=0,04). A análise sequencial dos estudos (TSA) não sugeriu conclusões definitivas sobre o assunto. Conclusão: As estatinas parecem ter efeito protetor contra infarto pós-operatório em cirurgia não-cardíaca, mas estão associadas a maior risco de insuficiência renal aguda em cirurgia cardíaca. Possíveis efeitos positivos ou negativos sobre a mortalidade não podem ser excluídos. Os dados dos estudos randomizados disponíveis até o momento ainda são insuficientes para conclusões definitivas sobre o uso perioperatório das estatinas. Estudos randomizados adicionais são necessários para avaliar o perfil de segurança e possíveis efeitos benéficos destas medicações nos desfechos pós-operatórios / Introduction: Previous studies supported potential beneficial effects of perioperative statin therapy to reduce postoperative complications. Accordingly, previous meta-analysis concluded that statin treatment decreases the perioperative incidence of mortality and myocardial infarction in non-cardiac surgery. In contrast, growing evidences on perioperative statins administration in cardiac surgery setting suggested neutral or even detrimental results. A recent systematic review and meta-analysis found that perioperative statin therapy in this population was associated with an increased incidence of postoperative acute kidney injury and a trend toward increased mortality. Due to the contrasting results and lack of definitive evidence, we performed a systematic review and meta-analysis of randomized controlled trials to examine the effects of perioperative statin therapy on postoperative outcomes in adult cardiac and non-cardiac surgery patients. Objective: To assess the association between perioperative statin therapy and postoperative myocardial infarction, stroke, acute kidney injury and mortality in patients submitted to cardiac and non-cardiac surgery. Methods: Pubmed, EMBASE, and Cochrane databases were searched through May 1st, 2018 for appropriate articles. Articles were independently assessed by 2 reviewers. Randomized controlled trials evaluating adult cardiac and non-cardiac surgery patients comparing perioperative statin therapy versus placebo or no treatment were included. Risk ratio (RR) or odds ratio (OR) and 95% confidence interval (CI) were obtained using fixedeffects meta-analyses. Trial sequential analysis (TSA) was performed to quantify the statistical reliability of data. The Cochrane methodology was used. Main outcomes were postoperative myocardial infarction, stroke, acute kidney injury, and mortality. Results: Data from 35 randomized controlled trials involving 8200 patients were included. Perioperative statin therapy was associated with lower incidence of postoperative myocardial infarction in noncardiac surgery compared to control (OR=0.44 [95% CI, 0.30 a 0.64], p < 0.0001), but not in cardiac surgery OR=0.93 [95% CI, 0.70 a 1.24], p=0.61). Higher incidence of acute kidney injury was evident in cardiac surgery patients receiving perioperative statins (RR=1.15 [95% CI, 1.00 a 1.31], p=0.05), but not in the non-cardiac surgery population (RR=1.52 [95% CI, 0.71 a 3.26], p=0.28). No difference in postoperative stroke and mortality was present in patients undergoing either cardiac or non-cardiac surgery. However, low risk of bias trials performed in cardiac surgery showed a higher mortality with statins versus placebo (OR=3.71 [95% CI, 1.03 a 13.34], p=0.04). Trial sequential analysis suggested no firm conclusions on the topic. Conclusions: Statins appear to be protective against postoperative myocardial infarction in non-cardiac surgery and associated with an increased risk of acute kidney injury in cardiac surgery. Possible positive or even negative effects on mortality could not be excluded. There is still insufficient randomized data for firm conclusions on perioperative statin therapy. Further randomized controlled trials should evaluate both the safety profile and possible effects on patients\' outcomes
134

 Avaliação da atividade de inibidor da Enzima 3- Metil - Glutaril Coenzimaa Redutase na viabilidade, ciclo celular e síntese de fatores de crescimento em células de meloma múltiplo.

Trojan, Paula Josiane Janowski 13 March 2012 (has links)
Made available in DSpace on 2017-07-21T19:59:56Z (GMT). No. of bitstreams: 1 Paula Josiane Janowski.pdf: 1415528 bytes, checksum: b8cff156f647bfc75021877c6b016d7b (MD5) Previous issue date: 2012-03-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The multiple myeloma (MM) reaches plasma cells that are completely different from each other, that produce high amounts of immunoglobulins. The genetic changes are multiple and complexes, affecting the disease course and the sensibility of the tumorous cells to the treatment. The bone marrow constitutes the ideal microenvironment for the disease development, secreting growth factors that are indispensable for the proliferation, survival and migration of tumourous cells. This project is evaluating the pravastatin effect, drug that inhibits the hydroxymethylglutaryl coenzime reductase (HMG-CoA reductase), in MM cells, from RPMI 8226 line. The cells were kept in RPMI culture media, added by 10% of fetal bovine serum in a temperature of 37ºC in atmosphere of 5% of CO2. After the addiction of pravastatin to the cells cultivation, in three different concentrations, cells proliferation, cells cycle and the growth factors were evaluated in 24, 48 and 72 hours. The factors evaluated were interleukin 6, the growth factor of the vascular endothelium, the proliferation factor of fibroblasts and the transformation β factor. They influence in the angiogenesis, cell proliferation, metastasis formation and in the tumorous cells answers to the chemotherapy agents. There was a reduction of the cell availability and cells accumulation in the phase G0/G1 of the cell cycle, and that these effects are more accentuated in higher pravastatin concentration and contact period. A reduction of factors FGF and VEGF has occurred. The results show that the effects provided by pravastatin could be beneficial to patients with MM and there can be perspectives for additional studies to be performed, proving the benefits and safety. / O mieloma múltiplo (MM) atinge células plasmáticas completamente diferenciadas, que produzem elevadas quantidades de imunoglobulinas. As alterações genéticas são múltiplas e complexas, afetando a sensibilidade das células tumorais às drogas empregadas e o decurso da doença. A medula óssea constitui o microambiente ideal para progressão da doença, secretando fatores de crescimento imprescindíveis para a proliferação, sobrevivência e migração das células tumorais. Neste trabalho buscou-se avaliar os efeitos da pravastatina, droga inibidora da enzima HMG-CoA reductase, em células de MM, linhagem RPMI 8226. As células foram mantidas em cultura, em meio RPMI, acrescido de 10% de soro fetal bovino, à temperatura de 37°C com atmosfera de 5% de CO2. Após adição da pravastatina ao cultivo celular, em três diferentes concentrações, avaliou-se a proliferação celular, ciclo celular e níveis dos fatores de crescimento em 24, 48 e 72 horas. Os fatores avaliados foram interleucina, Fator de crescimento endotelial, fator de proliferação dos fibroblastos e Fator de transformação β, que influenciam na angiogênese, proliferação celular,metastização e na resposta das células tumorais aos agentes quimioterápicos. Houve uma redução da proliferação celular e acúmulo de células na fase G0/G1 do ciclo celular, sendo que estes efeitos são mais acentuados em concentrações mais elevadas de pravastatina e tempo de contato maior. Ocorreu uma redução dos fatores FGF e VEGF. Os resultados mostram que os efeitos por pravastatina poderia ser benéfico para os pacientes com MM e abrem perspectivas para realização de novos estudos, comprovando seus benefícios e segurança.
135

Wound healing signals mediated by Rho/ROCK activation in response to radiotherapy and consequences fot treatmeny of late damage within normal tissues / Signaux de cicatrisation médiées par l'activation de la voie Rho/ROCK en réponse à la radiothérapie et conséquences pour le traitement de dommages choroniques des tissus normaux

Pasinetti, Nadia 15 June 2012 (has links)
La Radiothérapie occupe la deuxième place dans la liste de traitement du cancer le plus important après chirurgie. Le progrès technique récent, comme la radiothérapie avec modulation d'intensité (IMRT) ou la radiothérapie guidée par l'image (IGRT), en combinaison avec de nouveaux médicaments à action spécifique tels que les anticorps monoclonaux, sont une garantie d'augmentation de l'index thérapeutique. Cependant, la radiothérapie peut provoquer un’ altération du processus normal de réparation et d'induire le développement d'un cadre de fibrose dans un sous-ensemble de patients sensibles et dans les survivants à long terme au cancer. La principale caractéristique de la fibrose radio-induit est l'accumulation excessive et anormale de collagène composé principalement des éléments fibrillaire et immatures de la matrice extracellulaire (ECM).Les organes qui peuvent être touchés par ce phénomène sont le foie, la peau, les intestins, les reins et les poumons. D'un point de vue clinique, la fibrose peut être considérée comme une condition irréversible, sans solution. Nous et d'autres ont récemment montré que, outre l'activation de la TGF-β/Smad canonique, d'autres voies sont activées dans les tissus fibreux tels que la cascade de signalisation intracellulaire Rho/ROCK. Fait intéressant, la façon dont Rho/ROCK semble spécifiquement activé dans la fibrose intestinale radio-induite, fournis une justification pour un stratégie anti-fibrotique ciblé. L’ inhibition pharmacologique de Rho avec les statines, en fait, est en mesure de prévenir et même inverser les phénomènes de fibrose post-actinique intestinale.Avec ces prémisses, dans nos études, nous avons montré le rôle des statines (Simvastatine et Pravastatine) et d'un inhibiteur spécifique de ROCK (Y-27632) dans un modèle murin de fibrose pulmonaire obtenue avec une approche pharmacologique (Bléomycine - BLM) . Par la suite, nous avons développé un modèle de fibrose pulmonaire induite par l'irradiation complet du thorax et évalué la réponse à l'administration de la Pravastatine. La confirmation de la participation de la voie Rho/ROCK/CTGF dans la fibrose pulmonaire a été montré par immunohistochimie: le traitement à la Pravastatine normalise l'expression de trois marqueurs: RhoB, TGFβ-RII et CTGF.Après, dans deux modèles de fibrose radio-induite (intestinal et pulmonaire), nous avons analysé, grâce à l’immunohistochimie, les mécanismes sous-jacents l'action antifibrotique de la Pravastatine via l’axe MMP2-TIMP2. Très intéressant, quand la pravastatine a été administré à titre préventif ou curatif, nous avons trouvé un impact différent sur la fibrolyse.Enfin, in vitro, nous avons étudié par zymographie l'expression des gélatinases (MMP2 et MMP9) dans des cultures primaires des fibroblastes pulmonaire murins exposées à différentes doses de rayonnement et de Pravastatine. Le métalloprotéases semble être à son tour impliquée dans les mécanismes pro-fibrolytiques induits par les statines.Dans notre modèle animal de fibrose pulmonaire, la Pravastatine est capable d'inverser le processus fibrotique et les métalloprotéases semblent être impliqués à leur tour, in vivo et in vitro, dans les mécanismes pro-fibrolyse induits par le médicament.La multiplicité des acteurs impliqués dans la physiopathologie de lésions fibrotiques explique pourquoi la mise en place d'une stratégie thérapeutique efficace est si complexe. La recherche dans les processus mécaniques de dommages aux tissus normaux ont ouvert la voie à de nouvelles approches thérapeutiques. Ces nouvelles cibles comprennent la réduction de l’inflammation, de l'activation vasculaire et de la thrombose, ainsi que la découverte de nouvelles cibles moléculaires. Il existe une variété de modèles précliniques et des stratégies efficaces, mais de nombreux efforts doivent être déployés pour atteindre l'objectif difficile de protéger les tissus normaux des effets secondaires de la radiothérapie. / Radiotherapy is the second most important treatment modality after surgery in the treatment of cancer. Recent technical advancements, such as intensity-modulated radiation therapy (IMRT) or image-guided radiation therapy (IGRT), combined with new targeted drugs have significant promise for therapeutic outcome. However radiation treatment could result in disabling normal tissue injury and in the development of progressive fibrosis in a subset of sensitive patients and in long-term cancer survivors. The main feature of tissue fibrosis is excessive accumulation of abnormal and cross-linked collagen mainly composed of fibrillar and immature extracellular matrix (ECM) components.The organs that can be affected by this phenomenon are liver, skin, intestine, kidneys and lungs. From a clinical point of view, fibrosis can be seen as an irreversible condition, without solution. We and others recently showed that beside the activation of the canonical TGF-β/Smad pathway, other intracellular signaling cascades including the Rho/ROCK pathway are switched on in fibrotic tissues. Interestingly, the Rho/ROCK pathway seems differentially activated in radiation-induced intestinal fibrosis, thereby providing a rationale for a specific, targeted anti-fibrotic strategy. Pharmacological inhibition of Rho using statins indeed prevent and even reverse intestinal radiation fibrosis.In our studies, we showed the role of Statin (Pravastatin e Simvastatin) and a specific inhibitor ROCK inhibitors (Y-27632) in a mice model of pulmonary induced-fibrosis obtained by a pharmacological approach (Bleomycin – BLM). Indeed, we developed a model of lung fibrosis by complete irradiation of chest and tested Pravastatin action. Confirmation of the involvement of Rho/ROCK/CTGF pathway in lung fibrosis are shown by immunohistochemistry: Pravastatin-treament normalized the expression of three markers: RhoB, TGF-RII and CTGF.Then, in models of radiation induced gut and lung fibrosis, we analysed, from a immunohistological point of view, the underlying mechanisms of the antifibrotic action of Pravastatin via MMP2-TIMP2 axis. Interestingly we found a different impact on fibrolysis when Pravastatin was administered preventively or curatively.Finally, in vitro, we investigate by zymography the expression of Gelatinases (MMP2 and MMP9) in primary lung fibroblasts cultures exposure at the different radiation and Pravastatin doses. Metalloproteases would appear to be in turn involved in pro-fibrolytic mechanisms induced by statin.The multiplicity of actors involved in the pathogenesis of fibrotic lesions explains why the definition of an effective therapeutic strategy is so complex.Researches in mechanistic processes of normal tissue damage paved the way for new therapeutic approaches. These new targets include reduction of vascular activation, inflammation and thrombosis and new molecular targets definition. Effective strategies are multiple on preclinical models, but numerous efforts have to be made to achieve the complicated goal of protection of normal tissues from the side effects of radiation therapy. / La radioterapia è la seconda modalità di trattamento più importante dopo chirurgia neltrattamento delle neoplasie. I recenti progressi tecnici, come la terapia ad intensità modulata(IMRT) o l’image-guided radioterapia (IGRT), in combinazione con nuovi farmaci ad azionemirata come gli anticorpi monoclonali, costituiscono ulteriore garanzia di incrementodell’indice terapeutico. Tuttavia il trattamento radiante può causare un’alterazione delnormale processo di riparazione e indurre lo sviluppo di un quadro di fibrosi in unsottogruppo di pazienti sensibili e nei lungo-sopravviventi al cancro. La caratteristicacardinale della fibrosi radioindotta è l’eccessivo ed anomalo accumulo di collagene compostoprincipalmente di componenti fibrillari e immature della matrice extracellulare (ECM).Gli organi che possono essere interessati da questo fenomeno sono fegato, pelle,intestino, reni e polmoni. Da un punto di vista clinico, la fibrosi può essere vista come unacondizione irreversibile, senza soluzione. Noi ed altri recentemente abbiamo mostrato cheaccanto alla attivazione della via canonica TGF-β/Smad, altre vie vengono attivate nei tessutifibrotici come la cascata di segnalazione intracellulare della via Rho/ROCK. Interessantenotare che la via Rho/ROCK sembra specificatamente attivata nella radiazione indotta fibrosiintestinale, fornendo così una spiegazione razionale per una specifica, mirata strategia antifibrotica.L'inibizione farmacologica di Rho con le statine infatti è in grado di prevenire eaddirittura invertire i fenomeni di fibrosi intestinale post-attinica.Grazie a queste premesse, nei nostri studi, abbiamo mostrato il ruolo delle statine(Pravastatina e Simvastatina) e di uno specifico inibitore di ROCK (Y-27632) in un modellomurino di fibrosi polmonare indotta ottenuto con un approccio farmacologico (bleomicina -BLM). In seguito, abbiamo sviluppato un modello di fibrosi polmonare indottadall’irradiazione completa del torace e valutata la risposta alla somministrazione dellaPravastatina. In questo modello ed in un modello di fibrosi intestinale indotto da radiazioni,abbiamo analizzato, da un punto di vista immunoistologico, i meccanismi sottostanti l'azione9antifibrotica della pravastatina e il ruolo delle metalloproteasi (MMP2 e TIMP2). Infine, invitro, abbiamo indagato, mediante zimografia, l'espressione delle gelatinasi (MMP2 e MMP9)in culture primarie di fibroblasti polmonari murini esposti a differenti dosi di radiazione epravastatina.Nel nostro modello animale di fibrosi polmonare, la Pravastatina è in grado di renderereversibile il processo fibrotico e le metalloproteasi parrebbero essere a loro volta coinvolte,in vivo and in vitro, nei meccanismi pro-fibrolitici indotti dal farmaco.La molteplicità di attori coinvolti nella patogenesi delle lesioni fibrotiche spiegaperché la definizione di una strategia terapeutica efficace è così complessa. Ricerche neiprocessi meccanicistici di danno ai tessuti normali hanno aperto la strada a nuovi approcciterapeutici. Questi nuovi obiettivi comprendono la riduzione dell’ attivazione vascolare,dell'infiammazione e della trombosi, oltre alla definizione di nuovi target molecolari. Esistonomolteplici ed efficaci strategie su modelli preclinici, ma numerosi sforzi devono essere fattiper raggiungere il complicato obiettivo di proteggere i tessuti normali dagli effetti collateralidella radioterapia.
136

Persistence in the use of statins and the associated outcomes among Chinese patients with high risk for coronary heart disease.

January 2004 (has links)
Cheng Wai Ring Caroline. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 74-84). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Table of contents --- p.vi / Publications --- p.x / List of figures --- p.xi / List of tables --- p.xii / Abbreviations --- p.xiii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Coronary Heart Disease --- p.2 / Chapter 1.1.1 --- Epidemiology --- p.2 / Chapter 1.2 --- Hypercholesterolemia and CHD --- p.3 / Chapter 1.2.1 --- Atherosclerotic plaque and lipoprotein --- p.4 / Chapter 1.2.2 --- NCEP ATP III guidelines --- p.5 / Chapter 1.2.2.1 --- CHD risk assessment --- p.5 / Chapter 1.2.2.2 --- Target lipid control --- p.8 / Chapter 1.2.2.3 --- Therapeutic lifestyle changes --- p.9 / Chapter 1.2.2.4 --- Pharmacological interventions --- p.10 / Chapter 1.2.2.5 --- Adherence to lipid-lowering therapy --- p.13 / Chapter 1.3 --- Adherence to drug therapy --- p.14 / Chapter 1.3.1 --- Definition of adherence --- p.14 / Chapter 1.3.2 --- Methods to assess adherence --- p.16 / Chapter 1.3.2.1 --- Expressions of adherence measurements --- p.20 / Chapter 1.3.3 --- Time effect on adherence --- p.21 / Chapter 1.3.4 --- Predictors of adherence --- p.22 / Chapter 1.3.5 --- Impact of poor adherence to statins --- p.23 / Chapter 1.4 --- Objectives and hypotheses --- p.25 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- Study site --- p.27 / Chapter 2.2 --- Patient selection criteria --- p.28 / Chapter 2.2.1 --- Inclusion criteria --- p.28 / Chapter 2.2.2 --- Exclusion criteria --- p.29 / Chapter 2.3 --- Patient recruitment --- p.30 / Chapter 2.4 --- Assessments --- p.32 / Chapter 2.4.1 --- Adherence assessment --- p.32 / Chapter 2.4.1.1 --- Electronic monitoring --- p.32 / Chapter 2.4.1.2 --- Patient report --- p.33 / Chapter 2.4.1.3 --- Pill count --- p.34 / Chapter 2.4.1.4 --- Predictors of adherence --- p.34 / Chapter 2.4.2 --- Clinical outcome assessment --- p.35 / Chapter 2.4.2.1 --- Lipid control --- p.35 / Chapter 2.4.3 --- Economic outcome assessment --- p.35 / Chapter 2.4.3.1 --- Total direct medical cost --- p.35 / Chapter 2.4.3.2 --- Healthcare cost per member per month --- p.36 / Chapter 2.5 --- Sample size --- p.36 / Chapter 2.6 --- Statistical analysis --- p.37 / Chapter Chapter 3 --- Results / Chapter 3.1 --- Study sample --- p.40 / Chapter 3.1.1 --- Demographic characteristics --- p.41 / Chapter 3.1.2 --- Co-morbidity factors --- p.42 / Chapter 3.2 --- Adherence measurement --- p.44 / Chapter 3.2.1 --- Electronic monitoring --- p.44 / Chapter 3.2.2 --- Patient report --- p.45 / Chapter 3.2.3 --- Pill Count --- p.46 / Chapter 3.2.4 --- Correlation among methods for measuring adherence --- p.47 / Chapter 3.2.5 --- Trend of adherence and persistence over time --- p.48 / Chapter 3.2.6 --- Independent predictors of adherence --- p.49 / Chapter 3.3 --- Outcome assessment --- p.52 / Chapter 3.3.1 --- Clinical outcomes --- p.52 / Chapter 3.3.2 --- Economic outcomes --- p.52 / Chapter 3.4 --- Association between adherence and clinical outcomes --- p.53 / Chapter 3.4.1 --- Adherence and LDL-C reduction --- p.53 / Chapter 3.4.2 --- Adherence and NCEP ATP III target --- p.55 / Chapter 3.5 --- Association between adherence and economic outcomes --- p.55 / Chapter 3.5.1 --- Adherence and healthcare utilization --- p.55 / Chapter Chapter 4 --- Discussion and Conclusion / Chapter 4.1 --- Discussion --- p.59 / Chapter 4.1.1 --- Accuracy of patient report and pill count --- p.59 / Chapter 4.1.2 --- Persistence to statin therapy over time --- p.62 / Chapter 4.1.3 --- Predictors for patient adherence --- p.63 / Chapter 4.1.4 --- Clinical impacts of patient adherence --- p.66 / Chapter 4.1.5 --- Economic impacts of patient adherence --- p.68 / Chapter 4.1.6 --- Limitations --- p.70 / Chapter 4.2 --- Conclusion --- p.71 / References --- p.74 / Appendices / Appendix A-1. Framingham risk scoring system for male --- p.86 / Appendix A-2. Framingham risk scoring system for female --- p.87 / Appendix B-1. Information sheet provided to nurses of the Cardiology clinic --- p.88 / Appendix B-2. Information sheet provided to nurses of the Diabetes clinic --- p.89 / Appendix B-3. Information sheet provided to nurses of the Lipid clinic --- p.90 / Appendix C. Data collection form --- p.91 / Appendix D. Instruction sheet provided to the study patient --- p.94 / Appendix E. Unit cost of items from electronic dispensing record and Hong Kong Gazette 2003 for estimating total direct medical cost --- p.95
137

Modulation of porcine coronary artery BKCa and IKATP channels gatings by 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor. / Modulation of porcine coronary artery on calcium-activated and ATP-sensitive potassium channels gatings by 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor / CUHK electronic theses & dissertations collection

January 2008 (has links)
3-Hydroxy-3-Methylglutaryl Coenzyme A (HMG CoA) reductase is a 97 kDa glycoprotein located in the endoplasmic reticulum responsible for cholesterol biosynthesis in mammalian liver and intestine. HMG CoA reductase inhibitors (statins) (e.g. simvastatin, mevastatin and parvastatin) are used clinically to treat and prevent coronary artery diseases by reducing plasma LDL-cholesterol level. Recent studies have demonstrated that statins can provide beneficial effects (pleiotropic effects) beyond its lipid-lowering activity. However, the modulatory effects of statins on ion channels activities have not been fully explored. Hence, this study is designed to demonstrate the existence of the HMG CoA reductase in various human isolate cardiovascular preparations and the modulatory effect(s) of simvastatin on both large-conductance calcium-activated (BKCa) and ATP-sensitive (IKATP) potassium channels of porcine isolated coronary vascular smooth muscle cells. / In conclusion, our results demonstrated the biochemical existence of HMG CoA reductase in various human isolated cardiovascular preparations and porcine isolated coronary artery. Simvastatin modulates the BKCa and IKATP channels of the porcine isolated coronary artery via different and multiple cellular mechanisms. / In this study, we demonstrated the biochemical existence of the HMG CoA reductase in various human isolated cardiovascular preparations and porcine isolated coronary artery. In addition, we demonstrated that simvastatin modulates both the BKCa channels and IKATP channels of porcine isolated coronary artery via different mechanisms. Acute application of simvastatin (100 nM) slightly enhanced whereas simvastatin (&ge; 1 muM) inhibited the BKCa amplitude of porcine coronary artery smooth muscle cells. The classical HMG CoA reductase-mevalonate cascade is important in mediating the inhibitory effect of simvastatin observed at low concentrations (1 and 3 muM), whereas an increased PKC-delta protein expression and activation is important in simvastatin (10 muM)-mediated inhibition of BKCa channels. In contrast, the basal activity of the IKATP channels was not affected by simvastatin (1, 3 and 10 muM). However, acute application of simvastatin (1, 3 and 10 muM) inhibited the opening of the IKATP channels by cromakalim and pinacidil in a PP2A-dependent manner (sensitive to okadaic acid, a PP2A inhibitor). The okadaic acid-sensitive, simvastatin-mediated inhibitory effect on IKATP channel is mediated by an activation of AMPK in a Ca2+-dependent manner. Activation of AMPK probably increased the activity of the Na+/K+ ATPase and subsequently caused an influx of glucose via the SGLT1 down the Na + concentration gradient for the ouabain-sensitive, glucose-dependent activation of PP2A. / Seto, Sai Wang. / Adviser: Yiu-Wa Kwan. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3456. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 221-254). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
138

Pharmacogenetic and environmental determinants of response to HMG-CoA reductase inhibitors. / CUHK electronic theses & dissertations collection

January 2007 (has links)
A total of 146 Chinese patients with various degrees of hyperlipidaemia and high cardiovascular risk, suitable for treatment with rosuvastatin 10 mg daily and in whom it was possible to obtain baseline lipid profiles measured on no lipid lowering drug, were enrolled in to the study. The drug compliance was assessed by personal interview and 9 patients were excluded from the efficacy analysis because they stated their compliance was less than 80%. From the remaining 137 subjects, 62 had a clinical diagnosis of familial hypercholesterolaemia. Data for dietary intake were available in 121 of the 137 subjects. The average reduction in LDL-cholesterol in these subjects was 48.8 +/- 12.8% and as anticipated there was a wide range between individuals. The percentage reductions in LDL-cholesterol were significantly greater in the female than in the male subjects (-51.35 +/-10.89% vs. -46.38 +/-13.96%; p = 0.025), but this was no longer significant after adjustment for body weight. In patients with familial hypercholesterolaemia the absolute reductions in total cholesterol and LDL-cholesterol were significantly greater (p&lt;0.001) than in those without familial hypercholesterolaemia, but the percentage reductions were not significantly different in the two groups. The increases in HDL-cholesterol and the decreases in triglycerides were significantly greater in the subjects with familial hypercholesterolaemia than in those without familial hypercholesterolaemia, both for the absolute changes and for the percentage changes. There were no significant effects on the percentage changes in lipids with rosuvastatin treatment due to age, measurements of body fatness, smoking or alcohol drinking status, or having hypertension or diabetes. / Polymorphisms in the CYP2D6 gene were analyzed and the subjects were divided into 4 groups as wild-type or extensive metabolisers, heterozygotes for CYP2D6*10 and wild-type, homozygotes for CYP2D6*10, and subjects with one allele for poor metaboliser status. The groups in this order would be expected to have decreasing activity of the CYP2D6 enzyme. There was a tendency for greater reduction in LDL-cholesterol in groups with lower CYP2D6 activity, most obvious in male subjects and this was significant in the patients with familial hypercholesterolaemia comparing the first 3 groups. The fourth group had a low number of subjects, which may have biased that result. In the subjects without familial hypercholesterolaemia, the % change in LDL-cholesterol was similar in all genotype groups, but the % reduction in triglycerides was numerically higher in the wild-type group than in groups with CYP2D6*10 alleles and the group with poor metaboliser status showed a lower % reduction. These differences were not significant and may be influenced by the baseline levels of triglycerides, which were not corrected for in this analysis. / The daily calorie intake and percentage of different macronutrient intake was obtained by using seven days food recall records. Dietary intake of most nutrients with higher in male than in female patients and was higher in the patients compared to gender-matched population data. Higher intake of most nutrients was associated with higher baseline triglyceride levels, but not LDL-cholesterol levels in all patients, and in lower HDL-cholesterol levels in the patients without familial hypercholesterolaemia. Higher intake of total calories was associated with less percentage reduction in LDL-cholesterol with rosuvastatin in the patients without familial hypercholesterolaemia and a similar non-significant tendency was seen with higher intake of total fat, saturated fat and cholesterol. / The study described in this thesis examined the role of the CYP2D6*10 polymorphism on the lipid response to rosuvastatin in addition to a number of phenotypic factors such as diet, gender, measures of obesity and other medical conditions. / These findings suggest that the CYP2D6 genotype may have some influence on the lipid response to rosuvastatin, but it appears to interact with other factors including, gender, diet and the presence of familial hypercholesterolaemia. (Abstract shortened by UMI.) / Lui, Siu Hung. / "February 2007." / Adviser: Brian Tomlinson. / Source: Dissertation Abstracts International, Volume: 69-01, Section: B, page: 0248. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 165-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
139

Pharmacogenetics of rosuvastatin therapy and genetic determinants of some cardiovascular risk factors in Chinese patients. / CUHK electronic theses & dissertations collection

January 2010 (has links)
Although the clinical efficacy of statins has been well established, there is a wide inter-individual variation in the lipid responses to statins. Pharmacogenetic studies have identified some genetic differences that contribute to the variation, but overall the results have been disappointing. The studies described in this thesis were performed to examine whether certain genetic variants predicted the lipid responses to rosuvastatin in Chinese patients. Over 400 Chinese patients with increased risk of cardiovascular disease (CVD) who were treated with rosuvastatin 10 mg daily for at least 4 weeks (more than 97% of patients had at least 6 weeks treatment) were studied, including 166 having familial hypercholesterolaemia (FH) and 36 having rheumatoid arthritis (RA). They were genotyped for 135 polymorphisms in 62 candidate genes/loci potentially related to pharmacokinetics or pharmacodynamics of statins and lipid metabolism. Associations between genetic polymorphisms and the lipid responses to rosuvastatin were analyzed in 386 patients with good compliance. The associations between genetic polymorphisms and some risk factors for CVD including baseline lipid levels, high-sensitivity C-reactive protein (hsCRP), uric acid and bilirubin levels were also analyzed. / Some novel genetic determinants of the LDL-C response to rosuvastatin treatment have been identified in this study. The responses in HDL-C and triglycerides were related more closely to the baseline levels of these lipids than to any of the polymorphisms examined. Genetic associations with baseline lipid parameters, hsCRP, uric acid and bilirubin were identified and generally correspond with some of the previous reports of studies in Chinese and other ethnic groups. / The key findings of the study are as follows: 1. The polymorphisms most highly associated with the low-density lipoprotein cholesterol (LDL-C) response were 421C>A in the ATP-binding cassette G2 (ABCG2) gene (P=9.2x10 -7), followed by 18281G>A (V257M) in the flavin-containing monooxygenase 3 (FMO3) gene (P=0.0002), 1421C>G in the lipoprotein lipase (LPL) gene (P=0.002), and rs4420638 in the apolipoprotein E/C-I/C-IV/C-II (APOE/C1/C4/C2) gene cluster (P=0.004). These genetic polymorphisms and having FH totally explained 13.6% of the variance in percentage change in LDL-C in response to rosuvastatin. The greater percentage reduction in LDL-C in patients with the ABCG2 421AA genotype compared to those with the ABCG2 421CC genotype was equivalent to at least doubling the dose of rosuvastatin. 2. Three SNPs (glucokinase regulator [ GCKR] rs1260326, apolipoprotein AS [APOA5] -1131T>C and the solute carrier organic anion transporter 1B1 [SLCO1B1] 521T>C) tended to be associated with percentage changes in high-density lipoprotein cholesterol (HDL-C) (P&lt;0.05), but none of these reached the overall significance level. In multivariate stepwise regression analysis, baseline HDL-C (P=1.6x10 -6), having diabetes (P=0.0004) or RA (P=0.002) and the SLCO1B1 521T>C polymorphism (P=0.03) were determinants of HDL-C responses, contributing 9.9% of the variance in percentage change in HDL-C, but the genetic factors only contributed to 0.8% of the variance. 3. The triglyceride response to rosuvastatin was highly variable and was strongly related to baseline levels. The diacylglycerol acyltransferase-2 (DGAT2) rs10899113 C>T polymorphism tended to be associated with reduced triglyceride response in a gene-dose dependent manner. However, in multivariate stepwise regression analysis, baseline triglyceride level was the only factor that strongly related to the triglyceride response, explaining 14.4% of the variance. 4. This study has also analyzed relationships between on-treatment plasma hsCRP concentrations and cardiovascular risk factors and 14 single nucleotide polymorphisms in CRP and other candidate genes, which showed that central obesity, low HDL-C and CRP polymorphisms are major determinants of higher hsCRP levels in Chinese patients on treatment with rosuvastatin. 5. The association between genetic polymorphisms and lipid traits were analyzed in FH and non-FH patients separately due to their different lipid profiles. The analysis has shown that there were different genetic predictors of lipid levels in patients with and without FH and that more genetic factors appeared to affect the baseline lipid levels in patients with FH compared to non-FH patients, suggesting complex interactions between genetic and environmental factors and plasma cholesterol levels in patients with and without FH. 6. The SLC2A9 (solute carrier family 2, member 9) rs1014290 T>C was significantly associated with plasma uric acid levels in a gene-dose dependent manner (P=1.0x10-5) and the relationship was more pronounced in women or in patients without hypertension than in men or patients with hypertension. The ABCG2 421 C>A did not show a significant effect on uric acid levels. 7. The UGT1A1 (uridine diphosphate glucuronosyltransferases family, polypeptide A1) variants *28 (P=1.5x10 -9) and *6 (P=2.2x10-7) were independently associated with increased baseline bilirubin levels. Polymorphisms in SLCO1B1 did not appear to affect bilirubin levels in this study. / Hu, Miao. / Adviser: Brian Tomlinson. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 230-264). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
140

Metformin, statins and the risk and prognosis of endometrial cancer in women with type 2 diabetes

Arima, R. (Reetta) 01 October 2019 (has links)
Abstract Endometrial cancer (EC) is the fifth most common female cancer worldwide and its incidence is increasing. The prognosis of EC is fairly good. Histologically, ECs are categorized into endometrioid and non-endometrioid subtypes. Lately, the idea of repurposing existing medications for the prevention and co-treatment of EC has evoked interest in the scientific community. The results of preclinical studies involving various forms of antidiabetic medication (ADM) such as metformin, or cholesterol-lowering statins have been promising. In the previous epidemiological studies, the results of metformin and/or statin use and the risk and prognosis of EC have indicated either neutral or beneficial effects. At least some of these studies have several limitations, including a potential for several types of bias, and missing information on the dose and timing of medication, cancer-specific mortality or the histology of EC. The aim of this study was to find reliable further evidence on whether the use of metformin or statins could have beneficial effects on the risk and prognosis of EC in women with type 2 diabetes (T2D). Endometrioid and non-endometrioid EC were analyzed separately based on data from the Finnish Cancer Registry (FCR). In our study cohort of 92 366 women obtained from a nationwide diabetes database (FinDM) (1996 to 2011), the incidence rates of endometrioid (n = 590 cases) and non-endometrioid (n = 57 cases) EC were not found to differ between metformin users and users of other forms of oral ADM when adjusted for age, duration of T2D and use at any time of other forms of medication under study. We found insufficient evidence that metformin affects the prognosis of patients diagnosed with endometrioid (n = 1215) or non-endometrioid (n = 105) EC (1998 to 2011) after adjusting for year, age and stage at diagnosis of EC, and duration of T2D. However, in patients with endometrioid EC, mortality from other (predominantly cardiovascular) causes of death was decreased in metformin users compared with users of other types of oral ADM. Despite promising preclinical data, we were not able to confirm a beneficial effect of metformin use on the risk or prognosis of EC in women with T2D. In statin users, a lower risk of both EC subtypes and reduced cancer-specific mortality from non-endometrioid EC were observed. / Tiivistelmä Kohdun runko-osan syöpä on naisten viidenneksi yleisin syöpä, ja todettujen tapauksien määrä kasvaa. Syövän paranemisennuste on melko hyvä. Histologisesti syöpä jaetaan endometrioidi-muotoon ja ei-endometrioidi -muotoon. Alun perin muihin tarkoituksiin kehitettyjen lääkkeiden käyttö kohdun runko-osan syövän ehkäisyssä ja hoitoyhdistelmissä on ollut viime aikoina tieteellisen mielenkiinnon kohteena. Prekliinisten tutkimusten tulokset diabeteslääke metformiinin ja hyperkolesterolemian hoitoon käytettyjen statiinien osalta ovat olleet lupaavia. Aiemmissa epidemiologisissa tutkimuksissa metformiinin tai statiinien käytön vaikutukset kohdun runko-osan syövän riskiin ja ennusteeseen ovat olleet vaihtelevia. Osassa tutkimuksista on ollut ongelmia liittyen tilastollisten harhojen riskiin, puutteellisiin tietoihin lääkityksen kestosta ja kumulatiivisista annoksista sekä spesifisestä syöpäkuolleisuudesta ja syövän histologiasta. Kansalliseen diabetestietokantaan (FinDM) perustuvan tutkimuksemme tavoitteena oli selvittää, onko metformiinin tai statiinien käytöllä (Kelan lääkekorvaustilastot) kohdun runko-osan syövän riskiä vähentävää tai ennustetta parantavaa vaikutusta tyypin 2 diabetesta sairastavilla naisilla. Endometrioidit-syövät ja ei-endometrioidit -syövät analysoitiin erikseen Suomen Syöpärekisterin tietoihin perustuen. Kohortissamme (n = 92 366) ei todettu eroa endometrioidin (n = 590) tai ei-endometrioidin (n = 57) kohdun runko-osan syövän ilmaantuvuudessa metformiinia tai muita oraalisia diabeteslääkkeitä käyttävien naisten välillä (1996-2011), kun ikä, diabeteksen kesto ja muiden lääkitysten käyttö vakioitiin. Emme löytäneet näyttöä metformiinin käytön yhteydestä syöpäkuolleisuuteen endometrioidissa (n = 1 215) tai ei-endometrioidissa (n = 105) alatyypeissä verrattuna muihin diabeteslääkityksiin (1998-2011), kun ikä, syövän diagnoosivuosi ja levinneisyys sekä diabeteksen kesto vakioitiin. Endometrioidiin syöpään sairastuneilla metformiinia käyttävillä naisilla muu, valtaosalla sydän- ja verisuonitautiperäinen, kuolleisuus oli vähentynyt verrattuna muiden oraalisten diabeteslääkkeiden käyttäjiin. Aiemmista lupaavista tutkimustuloksista huolimatta emme todenneet metformiinilla olevan edullisia vaikutuksia kohdun runko-osan syövän kannalta. Statiinien käyttöön liittyi vähentynyt tämän syövän riski sekä vähentynyt syöpäkuolleisuus ei-endometrioidissa alatyypissä.

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