“Now that we have fascinating new results, we want to understand more. »
In the forests around the laboratory of the University of Greifswald, scientists captured thirty-five common noctules (Nyctalus noctula) wild, species which hibernates in large colonies. They collected the blood of these animals in the laboratory before releasing them into the forest. The team did the same with Egyptian flying foxes from the nearby Friedrich-Loeffler Institute, a German federal research agency for animal health and welfare. Then, finally, she obtained human blood from a blood bank.
In total, the study authors collected more than half a million red blood cells from the three species.
They compared human and bat cells using specialized software that analyzes cells as they are stretched and compressed by an external force.
“To my knowledge, there has never been such a detailed comparison between human and bat red blood cells,” says Gerald Kerth.
Common noctules, widespread in Europe, Asia and North Africa, hibernate during the winter, allowing them to survive temperatures as low as -7 degrees Celsius.
The team looked at how the three species’ red blood cells responded to three different temperatures: 37°C, roughly the core body temperature of humans and the two bat species; a little less than 23°C, that is to say the ambient temperature inside buildings; and 10°C, the temperature at which wild common noctules begin to hibernate.
As the cold intensified, the red blood cells of humans and bats became larger and stiffer, but only those of the latter grew more than they became stiff. The more the cold bit, the greater the ratio between the size and stiffness of the red blood cells belonging to the bats. On the other hand, as far as those of human beings are concerned, this has remained the same.
The study authors hypothesize that these tougher bat cells would have a considerable advantage: by staying longer in lung capillaries and muscles at low temperatures, the modified cells could allow for better consumption and distribution. oxygen throughout the body.
Gerald Kerth adds that the Egyptian fruit bats would have inherited from an ancestor this cellular adaptation that they retain today even if they no longer use it to hibernate.
If scientists could modify the membrane of human red blood cells to mimic those of bats, it could bring us closer to human hibernation.
This new “study is one of many small pieces of the puzzle on the pathway to torpor in humans,” says Marcus Krüger, a molecular biologist who researches space medicine at the Otto von Guericke University of Magdeburg. , in Germany, and who did not participate in the study.
“But many important questions remain unanswered, particularly about how to induce hibernation in humans. Is this something that could be achieved through fat accumulation, food deprivation, pharmacological support? »
It is also unclear whether some type of drug could instruct human cells to become much larger in proportion to their stiffness before entering the torpor state.
Of course, there are many other problems before a person can even get to Mars. Traveling in space means exposing yourself to radiation, suffering physical and muscular losses, as well as remaining confined. That’s not to mention supplies: it would take nearly seventy shuttles to transport the food and fuel needed to keep the people on board alive during the round trip to Mars.
Still, the study is an interesting development, Mikkael A. Sekeres, a hematologist at the University of Miami in Florida, wrote in an email.
