What causes space kidney disease?

As space agencies around the world set their sights on deep space missions, it is becoming increasingly important for scientists to understand how long-duration spaceflights affect our health. Masu. Researchers have shown that without Earth's protection, astronauts face health challenges, including an increased risk of cancer from radiation and reduced bone strength and muscle mass in zero gravity. . But what about the less visible health effects?

Researchers at University College London recently discovered how low gravity and high radiation affect the kidneys, an important organ that regulates fluid levels and filters blood in the body. We investigated this issue. Scientists first began to suspect that spaceflight might harm the kidneys when they noticed that kidney stone formation rates in astronauts were up to seven times higher than pre-flight estimates. Scientists suggested that this abnormality meant that even short spaceflights could affect the kidneys, and set out to understand the extent and causes of this effect.

The researchers used existing data from four human and 12 rodent spaceflight missions and four rodent space simulations exposed to low gravity and/or high radiation. I used it. Spaceflight mission data includes 86 astronauts and 101 mice who spent between 3 and 199 days in space. The space simulation tested 90 mice in gravity and radiation levels equivalent to up to 1.5 years in space. The data they collected included the molecular composition of mouse and human urine, blood, and feces before and after space exposure. They also performed their own targeted molecular and genetic analyzes on some frozen blood and kidney samples obtained from these experiments and simulations.

By analyzing blood and urine samples from 66 astronauts and kidney tissue from 57 mice after spaceflight simulations, researchers found out why astronauts frequently develop kidney stones after flights. We investigated whether Kidney stones on Earth are usually caused by high salt concentrations, but these small molecules were not observed in astronauts or mice after the flight. Instead, they lacked expression of key proteins that protect against kidney stones, such as alpha-tubulin. They also found overproduction of small molecules involved in protein production called aminoacyl-tRNAs, suggesting that the body was responding to physical stress. To pinpoint the cause, they focused on kidney-specific stress indicators.

The scientists then examined whether the stress associated with spaceflight changed the structure of the astronauts' kidneys. They explained that the kidney has the unique ability to change the internal structure of its tiny tubes and filters in just a few weeks depending on blood pressure and diet. To look for evidence of this rearrangement, the researchers looked at the same blood samples from humans and mice, but this time they looked at a subset of the genes they targeted.

They discovered that within a month of spaceflight, both starsThe aviators and mice had more active genes commonly associated with kidney remodeling than normal. The researchers independently confirmed these results using 3D scans and microscopic images of mouse kidneys after simulating space gravity and radiation, and found that kidney size increased by an average of 25% and abnormally Reconstruction with a large internal canal was demonstrated.

Finally, the scientists identified all the unique small molecules, genes, and proteins present in the blood of astronauts and mice after flights and simulations, and in patients with certain kidney-related diseases, such as kidney disease and amyloid disease. Compared to the typical one. They found many symptoms and similar configurations caused by: Kidney damage and inflammation, but there is no exact match. The research team therefore named these unique collective kidney dysfunctions “cosmic kidney disease.''

Researchers concluded that changes in the structure of the kidneys may cause kidney problems experienced by astronauts after space travel. They explained that when gravity decreases, the distribution and normal flow of fluids in the body is disrupted, just as water floats in spherical droplets instead of falling to the ground. They proposed that the kidneys adapt by changing their internal structure to require adequate flow. These changes can cause dysfunction such as inflammation, stress, protein synthesis, fluid levels, and kidney stone formation.

Scientists acknowledge that the study has limitations in that samples can only be collected after spaceflight and after normal Earth conditions have returned. But their study was the most extensive analysis of kidney health in space to date.

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