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Alterações fisiológicas e (epi)genéticas no corpo humano e a administração de fármacos numa missão espacial
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O ser humano, há vários séculos, tem tido um interesse profundo pelo universo que o cerca, especialmente pelo Espaço que se estende acima de nós. Essa curiosidade impulsionou o desenvolvimento de novas tecnologias, tornando possível a exploração espacial e as viagens a destinos cada vez mais distantes.
Assim, desde 1961, ano em que o primeiro homem viajou para o espaço, os cientistas têm-se dedicado continuamente a investigar as alterações que ocorrem no organismo humano durante a permanência no espaço, por meio de inúmeras experiências.
No espaço, a microgravidade (ou ausência de gravidade), assim como outros fatores, provoca modificações tanto na fisiologia quanto na genética dos astronautas.
São exemplos de alterações fisiológicas, entre outras, a perda muscular e óssea, o deslocamento de fluidos, a desregulação do sistema imunológico, mudanças no sistema cardiovascular e no trato gastrointestinal, as quais constituem aspetos a ter em conta na administração de medicamentos.
Por outro lado, ao nível da genética também podem ocorrer mudanças, já que as radiações cósmicas, microgravidade e o estresse têm um impacto significativo no DNA e, consequentemente, nas reações bioquímicas no corpo humano, nomeadamente devido a alterações em enzimas metabólicas ou até em recetores de fármacos.
Adicionalmente, na investigação, em astronautas, a área da epigenética permite obter conhecimento sobre as modificações na expressão génica, que embora não resultem de alterações da sequência do DNA, podem ser influenciadas por fatores ambientais. Esses estudos têm revelado mudanças epigenéticas significativas nas células dos astronautas, impactando processos como a metilação do DNA e modificações nas histonas. Tais alterações podem afetar a resposta imunológica, acelerar o envelhecimento celular e aumentar o risco de doenças, tanto durante a permanência no espaço quanto após o retorno à Terra.
Assim, é fundamental compreender as alterações fisiológicas e (epi)genéticas induzidas pelo ambiente espacial e incorporá-las no planeamento farmacoterapêutico. Nesse planeamento devem ser considerados tanto fatores relacionados ao próprio medicamento, como a sua estabilidade e via de administração, quanto aspetos específicos do astronauta, que podem exigir, por exemplo, ajustes individualizados nas doses. Dessa forma, será possível garantir tratamentos eficazes, prevenir reações adversas e preservar a saúde dos astronautas em missões cada vez mais longas e distantes da Terra.
Human beings, for several centuries, have had a deep interest in the universe that surrounds them, especially the Space that extends above us. This curiosity has fueled the development of new technologies, making space exploration and travel to increasingly distant destinations possible. Thus, since 1961, the year the first man traveled to space, scientists have continuously dedicated themselves to investigating the changes that occur in the human body during a stay in space, through countless experiments. In space, microgravity (or absence of gravity), as well as other factors, causes modifications in both the physiology and the genetics of astronauts. Examples of physiological changes include, among others, muscle and bone loss, fluid shifts, immune system dysregulation, changes in the cardiovascular system and the gastrointestinal tract, all of which constitute aspects to be considered in drug administration. On the other hand, changes can also occur at the genetic level, as cosmic radiation, microgravity, and stress have a significant impact on DNA and, consequently, on biochemical reactions in the human body, particularly due to alterations in metabolic enzymes or even drug receptors. Additionally, in research on astronauts, the area of epigenetics allows for obtaining knowledge about modifications in gene expression which, although they do not result from changes in the DNA sequence, can be influenced by environmental factors. These studies have revealed significant epigenetic changes in astronauts' cells, impacting processes such as DNA methylation and histone modifications. Such alterations can affect the immune response, accelerate cellular aging, and increase the risk of diseases, both during the stay in space and after returning to Earth. Thus, it is fundamental to understand the physiological and (epi)genetic changes induced by the space environment and incorporate them into pharmacotherapeutic planning. This planning must consider factors related to the medication itself, such as its stability and route of administration, as well as specific aspects of the astronaut, which may require, for example, individualized dose adjustments. In this way, it will be possible to guarantee effective treatments, prevent adverse reactions, and preserve the health of astronauts on missions that are increasingly longer and farther from Earth.
Human beings, for several centuries, have had a deep interest in the universe that surrounds them, especially the Space that extends above us. This curiosity has fueled the development of new technologies, making space exploration and travel to increasingly distant destinations possible. Thus, since 1961, the year the first man traveled to space, scientists have continuously dedicated themselves to investigating the changes that occur in the human body during a stay in space, through countless experiments. In space, microgravity (or absence of gravity), as well as other factors, causes modifications in both the physiology and the genetics of astronauts. Examples of physiological changes include, among others, muscle and bone loss, fluid shifts, immune system dysregulation, changes in the cardiovascular system and the gastrointestinal tract, all of which constitute aspects to be considered in drug administration. On the other hand, changes can also occur at the genetic level, as cosmic radiation, microgravity, and stress have a significant impact on DNA and, consequently, on biochemical reactions in the human body, particularly due to alterations in metabolic enzymes or even drug receptors. Additionally, in research on astronauts, the area of epigenetics allows for obtaining knowledge about modifications in gene expression which, although they do not result from changes in the DNA sequence, can be influenced by environmental factors. These studies have revealed significant epigenetic changes in astronauts' cells, impacting processes such as DNA methylation and histone modifications. Such alterations can affect the immune response, accelerate cellular aging, and increase the risk of diseases, both during the stay in space and after returning to Earth. Thus, it is fundamental to understand the physiological and (epi)genetic changes induced by the space environment and incorporate them into pharmacotherapeutic planning. This planning must consider factors related to the medication itself, such as its stability and route of administration, as well as specific aspects of the astronaut, which may require, for example, individualized dose adjustments. In this way, it will be possible to guarantee effective treatments, prevent adverse reactions, and preserve the health of astronauts on missions that are increasingly longer and farther from Earth.
Descrição
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Palavras-chave
Espaço Microgravidade Alterações fisiológicas Alterações genéticas Alterações epigenéticas Administração de medicamentos