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Abstract(s)
As doenças hipertensivas da gravidez (DHG) englobam um conjunto de condições
que afetam cerca de 10% de todas as gestantes no mundo inteiro. Este grupo complexo de
patologias para além da hipertensão gestacional também abrange a hipertensão
crónica/pré-existente e a pré-eclâmpsia (PE)/eclâmpsia. Ainda não é bem conhecida a exata
etiologia destas patologias, no entanto, ao longo dos anos, diversos estudos destacaram o
possível papel da testosterona (T) na fisiopatologia da PE. A T é uma hormona sexual cujo
efeito vasorelaxante foi anteriormente comprovado na artéria umbilical humana (AUH) de
mulheres não portadoras de DHG. No entanto, estudos prévios evidenciaram elevados
níveis de T no plasma materno de mulheres portadoras de PE, e, por conseguinte, uma
correlação positiva entre os níveis elevados desta hormona sexual e a presença e gravidade
da doença. Apesar da maior parte dos estudos se focar nos efeitos da T na PE, é igualmente
importante examinar esses efeitos na hipertensão gestacional, uma vez que é um precursor
para a PE. Compreender de que forma a T pode estar conectada a esta patologia pode ajudar
no diagnóstico precoce e na gestão de possíveis riscos.
Neste sentido, o presente trabalho teve dois principais objetivos: 1) avaliar como a
exposição à T afeta a contratilidade celular em cordões umbilicais de mulheres com
hipertensão gestacional; e 2) avaliar o papel de duas vias de sinalização endoteliais no efeito
a longo prazo da T. Para atingir o primeiro objetivo recorreu-se ao isolamento de AUH de
mulheres portadoras desta patologia para a obtenção de culturas de células do músculo liso.
Através da técnica de Planar Cell Surface Area (PCSA) foi possível analisar a resposta das
células ao agente contrátil serotonina (5-HT) e à T diretamente. Para avaliar o efeito a longo
prazo dos androgénios na contratilidade celular, as células foram incubadas com
dihidrotestosterona (DHT). As amostras de gestantes com hipertensão gestacional, após a
adição da T, passaram a expressar uma resposta vasoconstritora, comportamento contrário
ao observado no controlo (sem patologia). De seguida, de modo a atingir o segundo objetivo,
foram realizados estudos de reatividade vascular e simulações computacionais de Docking
Molecular. Os resultados indicam que 1) a inibição das vias endoteliais diminui a capacidade
vasorelaxante da T; 2) a incubação com DHT interfere com a vasorelaxação induzida pela
T; 3) a incubação com DHT potencializa a capacidade vasorelaxante do nitroprussiato de
sódio (SNP), dependendo do agente contrátil utilizado. E por último, os resultados
computacionais indicam que a T compete com o ligando natural por uma ligação ao centro
ativo da sGC, mas não se liga ao NPR-C porque o recetor selecionado possui uma cauda
citoplasmática curta sem o domínio catalítico GC. Em suma, a T em amostras celulares de gestantes com hipertensão gestacional tem
um efeito contrátil ao contrário do que é observado no controlo. O efeito da T é parcialmente
dependente das vias endoteliais COX e eNOS, tendo sido a última também comprovada em
estudos computacionais e o efeito a longo prazo da DHT interfere com a vasorelaxação
induzida pela T. Tendo em conta os resultados obtidos no PCSA, o uso de amostras de
hipertensão gestacional da AUH para estudos de reatividade vascular oferecem uma
oportunidade para perceber de que forma a T afeta a contratilidade vascular e possíveis
efeitos negativos que pode causar no desenvolvimento do feto.
Hypertensive disorders of pregnancy (HDP), including gestational hypertension, pre-existing/chronic hypertension, and preeclampsia (PE), encompass a range of conditions that affect about 10% of pregnancies worldwide. The etiology of these conditions is not fully understood however, throughout the years multiple studies have highlighted the potential role of testosterone (T) in pathogenesis of PE. T is a sexual hormone which vasorelaxant effect has been previously demonstrated in the human umbilical artery (HUA) of normotensive women, but previous studies have found increased T levels in maternal plasma of women with PE and, therefore, a correlation between high T levels and the disease has been made. Although much focus has been on PE it’s equally important to investigate T effects on gestational hypertension since the latter is a precursor of PE. Understanding its association with T may provide insights into early diagnosis and in the management of possible risks. Moreover, the present work aimed to 1) evaluate how T affects cells contractility in cell samples from the umbilical cord of women with gestational hypertension and 2) evaluate T effect in endothelial signaling pathways in T long-term effect. To achieve the first goal, we used HUA isolated from women with the disease to obtain smooth muscle cell cultures. Through the Planar Cell Surface Area (PCSA) technique, it was possible to analyze the response of the cells to the contractile agent serotonin (5-HT) and to T directly. To assess the long-term effect of androgens on cell contractility, cells were incubated with dihydrotestosterone (DHT). The samples of pregnant women with gestational hypertension, after the addition of T, began to express a vasoconstrictor response, the opposite behavior observed in the control (without pathology). Then, to achieve the second goal, vascular reactivity studies and computational simulations of Molecular Docking were performed. The results show that 1) the inhibition of endothelial pathways decreases the vasorelaxant capacity of T; 2) and that DHT incubation interferes with T-induced vasorelaxation; 3) incubation with DHT potentiates the vasorelaxant capacity of sodium nitroprusside (SNP) depending on the contractile agent used. And finally, the computational results indicated that T competes with the natural ligand for a binding to the active center and that it does not bind to NPR-C because the selected receptor has a short cytoplasmatic tail without a GC catalytic domain. In summary, T in cell samples from pregnant women with gestational hypertension has a contractile effect contrary to what is observed in the control. T effect is partially dependent on COX and eNOS endothelial pathways, the latter having also been proven in computational studies and the long-term effect of DHT interferes with T-induced vasorelaxation. Taking into the account the results obtained in the PCSA, the use of gestational hypertension samples from the HUA for vascular reactivity studies offers an opportunity to understand how T affects vascular contractility and possible negative outcomes it may have on the development of the fetus.
Hypertensive disorders of pregnancy (HDP), including gestational hypertension, pre-existing/chronic hypertension, and preeclampsia (PE), encompass a range of conditions that affect about 10% of pregnancies worldwide. The etiology of these conditions is not fully understood however, throughout the years multiple studies have highlighted the potential role of testosterone (T) in pathogenesis of PE. T is a sexual hormone which vasorelaxant effect has been previously demonstrated in the human umbilical artery (HUA) of normotensive women, but previous studies have found increased T levels in maternal plasma of women with PE and, therefore, a correlation between high T levels and the disease has been made. Although much focus has been on PE it’s equally important to investigate T effects on gestational hypertension since the latter is a precursor of PE. Understanding its association with T may provide insights into early diagnosis and in the management of possible risks. Moreover, the present work aimed to 1) evaluate how T affects cells contractility in cell samples from the umbilical cord of women with gestational hypertension and 2) evaluate T effect in endothelial signaling pathways in T long-term effect. To achieve the first goal, we used HUA isolated from women with the disease to obtain smooth muscle cell cultures. Through the Planar Cell Surface Area (PCSA) technique, it was possible to analyze the response of the cells to the contractile agent serotonin (5-HT) and to T directly. To assess the long-term effect of androgens on cell contractility, cells were incubated with dihydrotestosterone (DHT). The samples of pregnant women with gestational hypertension, after the addition of T, began to express a vasoconstrictor response, the opposite behavior observed in the control (without pathology). Then, to achieve the second goal, vascular reactivity studies and computational simulations of Molecular Docking were performed. The results show that 1) the inhibition of endothelial pathways decreases the vasorelaxant capacity of T; 2) and that DHT incubation interferes with T-induced vasorelaxation; 3) incubation with DHT potentiates the vasorelaxant capacity of sodium nitroprusside (SNP) depending on the contractile agent used. And finally, the computational results indicated that T competes with the natural ligand for a binding to the active center and that it does not bind to NPR-C because the selected receptor has a short cytoplasmatic tail without a GC catalytic domain. In summary, T in cell samples from pregnant women with gestational hypertension has a contractile effect contrary to what is observed in the control. T effect is partially dependent on COX and eNOS endothelial pathways, the latter having also been proven in computational studies and the long-term effect of DHT interferes with T-induced vasorelaxation. Taking into the account the results obtained in the PCSA, the use of gestational hypertension samples from the HUA for vascular reactivity studies offers an opportunity to understand how T affects vascular contractility and possible negative outcomes it may have on the development of the fetus.
Description
Keywords
Androgénios Artéria Umbilical Humana Células do Músculo Liso Hipertensão Gestacional