Astronauts not only risk getting blown-up on exiting Earth's atmosphere; risk getting blown-out into the unforgiving vacuum of space, and risk dying in a fiery inferno burning up on re-entry, they also age faster thanks to the lack of gravity. Now researchers have found the enzyme responsible for killing-off their cells including their immune system, which could also be inhibited here on Earth to help slow the aging process.
We age because all our cells have a finite lifespan. They divide to create new cells, but each division removes a little bit off a safety block at the end of your chromosomes called the telomere. Once that block has been warn down your DNA can fall apart and you can no longer create new cells. At the end of a cell's life it will commit suicide (apoptosis). Basically the cells stop functioning, their membranes break-up and the cell dies. Astronauts suffer from increased apoptosis, especially within their immune cells, thanks to the microgravity of space. That leads to the weakened resistance to disease that’s characteristic of aging.
Apparently it’s down to an enzyme called 5-lipoxygenase, which is hyperactive in the lack of gravity of space causing increased cell death. By sending some healthy white blood cells up to the ISS for tests, scientists were able to compare cells in microgravity with those in simulated Earth gravity (using a centrifuge) and discovered the pesky culprit.
The theory is that by inhibiting 5-lipoxygenase, you’ll be able to reduce the rate of apoptosis of an astronaut's immune cells, reducing the dangers of space travel for us all (you do want to go into space someday, right?). There’s also the possibility that that same enzyme can be inhibited in gravity-loving humans too, and help reduce the aging process back here on Earth. It’s unlikely that we’ll be able to stop aging entirely without serious side effects though, but there’s no reason we can’t prolong our lives like this by many hundreds of years.
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