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A search that touches the stars

Queen’s multidisciplinary research projects explore the impact of space travel on health, including bone loss and aging.

Experiencing spaceflight and being among the stars is an out-of-this-world dream for many, but for astronauts there can be serious health consequences that come with space travel.

The Canadian Space Agency (CSA) has identified three risks related to human spaceflight as high priorities: bone fragility, mission risks associated with altered metabolism, and the effect of the nutritional composition of the diet on health during space missions. With CSA support, Queen’s research teams are exploring how to make space travel safer by better understanding how astronauts’ diets affect bone loss and how spaceflight can impact astronauts’ DNA and the aging process.

Prevent bone loss in space

Rachel Holden (Medicine)

Research shows that astronauts lose substantial amounts of bone during space missions. It’s a mystery that inspired Queen’s researchers to take a closer look at a mineral commonly found in many foods: phosphate. Phosphate is important for bone health, but abnormalities in the way the body processes phosphate have been linked to bone loss on Earth. Since astronauts on the International Space Station consume high levels of phosphate, this led the multidisciplinary research team of Heidi Ploeg (mechanical and materials engineering) and Rachel Holden (medicine), experts in orthopedic biomechanics and calcification vascular in chronic kidney disease, to wonder if there is an association.

Normally, the phosphate a person consumes would go into their bloodstream and any excess would be eliminated by the kidneys. However, if a person’s kidneys aren’t working properly, they can develop high levels of phosphate in their blood, which can stimulate the loss of calcium from their bones. Researchers are now finding that this outcome of weaker bones in people without kidney problems is influenced by diets high in phosphate due to its addition by food manufacturers. Since food in space is fortified with inorganic phosphate for preservation, this could also contribute to bone loss in astronauts.

“Over the past five years, it has become clear that dietary phosphate intake can promote cardiovascular disease and bone loss in people with adequate kidney function. Dietary phosphate intake has increased dramatically over the past 10 years as inorganic phosphate is increasingly added to foods for preservation by the food manufacturing industry,” says Dr. Holden.

Heidi Ploeg
Heidi Ploeg (mechanical and materials engineering)

For Dr. Ploeg, Chair for Women in Engineering at Queen’s, the project provides exciting insights into how bone can adapt to its environment.

“Bone is an amazing structure. It is beautifully complex and most importantly, it adapts in response to its surroundings. Engineers can learn more about optimal, self-healing structures by studying biological structures like bone,” says Dr. Ploeg. “If we can better understand this process, we can better assess the risk of fragility fractures and reduce these fracture rates through treatments such as diet, physiotherapy and pharmaceuticals.”

Understanding how dietary phosphate promotes bone loss could reduce the burden of chronic disease in our aging society on Earth through regulations, and could contribute to the overall health of astronauts and the success of long-duration space missions in the future.

How does DNA replicate in microgravity?

Another Queen’s research team studying human health during space travel is Virginia Walker’s biology lab. The team’s research has shown that DNA replication in microgravity – a small amount of gravity like that found in space, causing astronauts to “float” – is less precise than under Earth’s gravity. . This could pose health risks for astronauts, including cancer and age-related problems for long periods in space, such as during missions to a future lunar station or to Mars. To do this, graduate student Aaron Rosenstein flew two missions aboard the CSA/National Research Council Falcon 20 aircraft, better known as the “vomit comet,” which simulates spaceflight.

Dr. Walker’s interest in space began when she was a child and the first lunar mission, Apollo 11, was launched in 1969. This interest was furthered by the show Star Trek, while Rosenstein grew is rightly inspired by Star Trek, Next Generation.

Aaron Rosenstein prepares for a flight on the
Aaron Rosenstein, a graduate student at Queen’s at the time, flew two missions aboard the CSA/National Research Council Falcon 20 jet, better known as the ‘vomit comet’, which simulates a space flight. (Photo provided)

Dr. Walker’s research in the area of ​​molecular genetic responses to stress has led her to search for extreme habitats, including those that are models for Mars. His lectures on astrobiology caught the imagination of Rosenstein, who at the time was an undergraduate student in life sciences. He and others started a student club and invited Dr. Walker to be the academic advisor. The work of this club led to a recently completed CSA research grant.

Their study found that DNA polymerases – the enzymes essential for DNA replication – make more errors in microgravity. This means there could be a health risk for astronauts on extended missions in space, as a decrease in the accuracy of DNA replication could lead to premature aging and cancer. Dr. Walker says this demonstrates the importance of designing spacecraft that mitigate these negative effects.

“Our research, showing that more errors can be made during DNA replication in microgravity, will surely bolster the efforts of the international community to create artificial gravity by rotating space stations, for example,” says the Dr Walker.

As humans continue to push the boundaries of space travel, the CSA has identified significant health implications. The work of Dr. Walker, Dr. Ploeg and Dr. Holden will contribute to research aimed at making spaceflight safer for those who venture off Earth.

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