Space

Leaky gut added to list of health problems faced by astronauts

Leaky gut added to list of hea...
A new study has found that microgravity can affect the cells lining the walls of the intestines
A new study has found that microgravity can affect the cells lining the walls of the intestines
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A new study has found that microgravity can affect the cells lining the walls of the intestines
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A new study has found that microgravity can affect the cells lining the walls of the intestines

Humans evolved to thrive here on Earth, so as soon as you take us away from that environment, all sorts of health problems arise. Now, researchers from the University of California Riverside and San Diego have found evidence of a new problem. Microgravity simulations show that our guts can become “leaky” after a stint in space, increasing the chances of certain infections and diseases for weeks afterwards.

The human digestive system is a pretty extreme place. Not only is it full of stomach acid that would dissolve other organs, but it contains a vast ecosystem of microorganisms that can cause dangerous infections if they escape into other parts of the body.

To keep us safe, our intestines are lined with epithelial cells that form an impermeable barrier against bacteria and other nasties. At least, it’s supposed to be impermeable – sometimes it’s weakened by illness or poor diet, allowing things to get through that really shouldn’t. This in turn can cause chronic conditions like type 1 diabetes, inflammatory bowel disease, and liver disease.

For the new study, the team wanted to investigate whether the microgravity of space affects this barrier in the human gut. Already, studies have shown that thanks to low gravity and high radiation, space travel can potentially weaken astronauts’ bones and muscles, induce symptoms of dementia, increase chances of cardiovascular disease, and even change gene expression.

To study the effects on the gut, the researchers cultured intestinal epithelial cells in a bioreactor that spins quickly, to simulate the effects of microgravity. After 18 days in this environment, the team stopped the spinning and examined the cells.

It was found that these epithelial cells had delayed formation of “tight junctions,” which connect individual cells together. With these connections weakened, the wall becomes permeable, or “leaky,” which was demonstrated by exposing them to acetaldehyde. This alcohol metabolite is known to normally weaken the barrier, and the microgravity cells had a harder time shrugging off those effects.

“Our study shows for the first time that a microgravity environment makes epithelial cells less able to resist the effects of an agent that weakens the barrier properties of these cells,” says Declan McCole, lead researcher on the study. “Importantly, we observed that this defect was retained up to 14 days after removal from the microgravity environment.”

The team says these findings could have implications for the health of astronauts in space and even after they return to Earth. Unfortunately the gut seems particularly problem-prone – another recent study on mice found that cosmic radiation can affect the ability of intestinal cells to absorb nutrients, and increase cancer risk.

All up, it seems that space travel is pretty taxing on the human body. For now, it seems safer for the majority of us to stay here on Earth – so we had better start looking after it.

The research was published in the journal Scientific Reports.

Source: University of California Riverside

6 comments
martinwinlow
Surely it's time we built a new ISS - *with artificial gravity* even if it isn't full Earth gravity... How much extra would such a design cost? And, whilst I'm at it, why can't we keep 2nd stage rockets in orbit and strap them together to re-use as building blocks for orbiting space platforms?
NeilBarton
As a passionate lover and admirer of all things in SPACE TRAVEL and the fact that everything is speeding up ever faster etc.the one thing that is beginning to stand-out larger than ever before is the need for astronauts to have and survive for any length of time and period in space is internal GRAVITY wherever they operate. Surely some one/company is working on all this?
Bruce Anderson
I wonder if the same effects would exist for low gravity environments (like on Mars) as with microgravity environments. It may take longer for symptoms to manifest, but unless there is a way to get back to normal gravity, or create it artificially, it would be a death sentence.
Douglas Rogers
When the railroad was invented some experts wondered if people could survive speeds of 60 miles per hour.
christopher
"spins quickly" would increase relative "gravity", not decrease it. I'd expect it's impossible to make gravity-based assumptions from earth-run experiments, because the number of other causes that come with attempting to simulate micro-gravity are so many, that you're never going to know if the "gravity" part was the trigger or not. Have astronauts suffered this? Have examinations of them revealed it?
ReservoirPup
@Douglas Rogers - thanks for the piece of unbeatable logic! What if someone is dragged on tarmac at 60 miles per hour? You say it has nothing in common with the space travel, but the recent studies indicate that poor someone is almost naked. Will you take your chances?