(ORDO NEWS) — Experiments with astronauts on the ISS have shown that the rate of destruction of red blood cells in space increases by more than one and a half times.
Humans are not very well adapted to being in outer space, even aboard pressurized ships. Excess radiation and lack of gravity, lack of mobility and isolation – all this has a bad effect on the state of the cells and the whole organism.
In particular, anemia, a deficiency of hemoglobin in the blood, also develops. This happens due to the accelerated destruction of red blood cells: this is the conclusion of the authors of a new article published in the journal Nature Medicine .
Erythrocytes (red blood cells) are the smallest and most numerous, and one of the shortest living cells in the human body.
Every second, about two million red blood cells are removed from circulation, being destroyed during hemolysis , but new ones are constantly replacing them. However, it has long been noticed that this process is disturbed in space. Already in the first days of the flight, the content of erythrocytes in the blood drops by 10-12 percent.
Subsequently, it begins to grow, but it never returns to normal. The phenomenon of such “space anemia” has been known for a long time, although its exact cause remains unclear. It is assumed that it occurs due to the body’s attempts to adapt to microgravity conditions and is associated with a general decrease in blood volume.
This becomes especially noticeable upon returning to Earth, when additional fluid enters the blood, and the number of red blood cells is in no hurry to return to normal.
A team of Canadian doctors led by Guy Trudel studied the condition of 14 astronauts who spent six months on board the ISS. During the flight, they saved samples of their own exhalation: one – five days after arriving at the space station, the second – after 12 days, then after three months and six, just before returning to Earth.
After receiving the samples, the scientists analyzed them using gas chromatography, determining the content of carbon monoxide (CO) with great accuracy.
The main source of these molecules is hemolysis – the process of direct destruction of red blood cells in the blood. Therefore, the measurements made it possible to estimate the intensity of hemolysis during the space flight.
Judging by these data, it grows by 54 percent compared to the norm – relatively speaking, about three million red blood cells die every second instead of two. Blood samples taken by the astronauts immediately after their return showed that five of the 13 astronauts had their red blood cell count drop to pathological levels.
Further blood tests showed that in the following months, the level of red blood cells gradually returned to normal. However, even a year after returning to Earth, the astronauts’ hemolysis proceeded noticeably faster than usual, and anemia persisted.
The reason for these processes is still unknown. “Hemolysis causes anemia, but knowing what causes hemolysis is the next step,” says Guy Trudel. It is also unclear how long the human body is able to withstand an increase in hemolysis by more than one and a half times.
Future missions to Mars will require perhaps more than a year and a half in space, and far from Earth orbit, where the ISS operates. It is possible that before you go there, you will have to deal with “space anemia.”
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