A recent study led by researchers at Karolinska Institutet in Sweden has examined how T cells of the immune system are affected by weightlessness. The outcomes, that are published within the journal Science Advances, could explain why astronauts’ T cells grow to be less energetic and fewer effective at fighting infection.
The subsequent steps within the exploration of space are human missions to the moon and to Mars. Space is an especially hostile environment that poses threats to human health. One such threat is changes to the immune system that occur in astronauts while in space and that persist after their return to Earth. This immune deficiency can leave them more vulnerable to infection and result in the reactivation of latent viruses within the body.
If astronauts are to find a way to undergo protected space missions, we want to know how their immune systems are affected and check out to search out ways to counter harmful changes to it. We have now been able to research what happens to T cells, that are a key component of the immune system, when exposed to weightless conditions.”
Lisa Westerberg, study leader, principal researcher, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
Within the study, the researchers have tried to simulate weightlessness in space using a technique called dry immersion. This involves a custom-made waterbed that tricks the body into considering it’s in a weightless state. The researchers examined T cells within the blood of eight healthy individuals for 3 weeks of exposure to simulated weightlessness. Blood analyses were performed before the experiment began, at 7, 14 and 21 days after the beginning, and at 7 days after the experiment ended.
They found that the T cells significantly modified their gene expression – that’s to say, which genes were energetic and which weren’t – after 7 and 14 days of weightlessness and that the cells became more immature of their genetic programme. The best effect was seen after 14 days.
“The T cells began to resemble more so-called naïve T cells, which haven’t yet encountered any intruders. This might mean that they take longer to be activated and thus grow to be less effective at fighting tumour cells and infections. Our results can pave the best way for brand spanking new treatments that reverse these changes to the immune cells’ genetic programme,” says Carlos Gallardo Dodd, PhD student on the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet and shared first writer with researchers Christian Oertlin and Julien Record at the identical department.
After 21 days, the T cells had “adapted” their gene expression to weightlessness in order that it had almost returned to normal, but analyses carried out seven days after the experiment ended showed that the cells had regained among the changes.
The researchers now plan to make use of Esrange Space Centre’s sounding rocket platform in Kiruna, Sweden, to check how T cells behave in weightless conditions and the way their function is affected.
The study was financed by the Swedish National Space Agency, the Swedish Research Council and Karolinska Institutet and was conducted in close collaboration with Claudia Kutter’s research group at Karolinska Institutet/SciLifeLab and collaboration partners at IBMP Moscow and Latest York University Abu Dhabi.
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Journal reference:
Gallardo-Dodd, C. J., et al. (2023) Exposure of volunteers to microgravity by dry immersion bed over 21 days leads to gene expression changes and adaptation of T cells. Science Advances. doi.org/10.1126/sciadv.adg1610.