what would happen if a human traveled to mars
Equally humans ready to venture deeper into outer infinite, including potential trips to Mars, researchers are hard at work trying to understand and mitigate the effects of depression gravity and radiation on space travelers' bodies.
"People call back of technology every bit the limiting gene in space flight, but it'south not," said Thomas Lang, PhD, a professor of radiology and biomedical imaging at UC San Francisco. "Human physiology is the limiting factor."
Spaceflight seems to have a specially notable effect on the musculoskeletal, cardiovascular and immune systems. Many of the changes researchers are seeing as a result of spaceflight are similar to those seen in aging, though they happen much faster in space.
"Nosotros're attuned to living in gravity," Lang said.
As private aerospace companies and NASA are competing to exist the first to land on Mars, UCSF researchers, and many others nationwide, are studying the effects of space travel – and trying to find ways to offset those impacts.
Os Loss, Back Pain and Stale Plums
Since the first Apollo space flights in the 1960s and '70s, the effects of space on muscles and basic has been apparent. Later just eight days in orbit, the Apollo astronauts were so weak that they had to be pulled from their landing capsules.
In the following decades, astronauts, such every bit those on the International Space Station (ISS), began to practise to go along their bones and muscles conditioned during their six-calendar month stays. Still, many astronauts suffer back pain for years later on returning to World.
To figure out why the back pain occurs later on the exposure to low gravity, Jeffrey Lotz, PhD, the David Bradford Endowed Chair of Orthopedic Surgery at UCSF, recently studied the spines of astronauts after their time in space.
What he found surprised him.
He'd imagined that the back hurting arose from disks swollen with h2o that would ordinarily get squeezed out by keeping an upright posture in gravity. Instead, he discovered the source of the back pain was deconditioning of the multifidus muscles, small muscles that connect and support the vertebrae.
Lotz is working with NASA to devise a program of multifidus exercises that astronauts can do inside the constraints of a spaceship in zero gravity.
Exercise is fundamental not just for muscle strength, simply for bone health also, and Lang has been studying the effect of space travel on bones for decades. "Bones aren't just a difficult framework," he said. "They grow and repair themselves in response to supporting loads against gravity."
A lack of gravity interrupts the natural cycle of bone role, which goes something like this: Os cells called osteocytes find regions of decreased strain or damage to bone tissue, triggering other cells, called osteoclasts, to resorb bone that no longer is needed to see the strain or has been damaged by repetitive strain. The work of osteoclasts triggers however another cell, the osteoblast, to move in and rebuild the bone where it is needed.
In the absence of gravity the rebuilding doesn't seem to happen as a result of the reduced strain on bone. This may put astronauts in danger of bone loss and fractures during their missions. Daniel Bikle, Md, PhD, professor of medicine and dermatology, using mouse studies, determined that microgravity affects communication between os cells necessary for the os growth and repair procedure.
"It's a bidirectional signaling pathway," says Bikle. "The bone cells regulate each other's role." Lack of gravity produces an interruption in that signaling, and the osteoclasts continue to resorb bone, just the osteoblasts don't furnish it. Bikle believes this same pathway might exist involved in osteoporosis. If so, unraveling the details should provide insight that benefits a population far larger than space travelers.
Lang assessed bone density of astronauts returning from the ISS and found that after half-dozen months, they had lost between 6 percent and 9 per centum of the full os density from their hips – losing virtually as much in a month as a postmenopausal woman loses in a year. In a report focused on bone loss in the hip, Lang and colleagues constitute that one year afterwards flight, the total os mass was almost fully recovered but recovered bone was redistributed, resulting in a bone architecture resembling that of an older person.
Radiation exposure, in add-on to microgravity, during spaceflight causes bone loss for astronauts, though one study points to a surprising prescription for this.
Bernard Halloran, PhD, a professor in the Department of Medicine, found that mice subjected to radiations and fed a diet containing plum powder lost significantly less bone.
His adjacent steps are to discern what compounds in the prunes are responsible for the effect. "This approach shows a lot of hope, simply it'south not equally simple as sending people into infinite with a truckload of prunes," he said. "Nosotros need to isolate the chemical compound and put it in a pill."
Heart of the Matter: The Cardiovascular Organization
The radiation and low gravity of space also has an touch on on the body's vascular system, causing circulatory problems for astronauts when they return to Earth and an increased risk of heart assault later in life.
Marlene Grenon, MD, associate professor of vascular surgery, has had a longtime interest in the effects of space flying on the vascular system. "Astronauts are in good shape, and practice protocols are part of their lives," said Grenon. "So we desire to know what'south going on here. Is it radiations? Gravity? Other physiological factors?"
Grenon, who has a diploma in Space Sciences from the International Space University and has developed UCSF'south kickoff course on the effect of spaceflight on the body, has studied the effects of simulated microgravity on the function of vascular endothelial cells which line the inside of blood vessels.
Grenon cultured these cells and placed them in an environment that false very depression gravity. She institute that the lack of gravity causes a decrease in the expression of sure genes in the cells that bear on adhesion of plaque to the vessel wall. While the implications of these changes aren't however clear, it's evident that a lack of gravity affects jail cell role.
In addition, previous work by Grenon showed that microgravity creates changes in the cells that carry electricity in the heart, which may put astronauts at take chances of cardiac arrhythmias.
Grenon'south colleagues Sonja Schrepfer, MD, PhD, and Tobias Deuse, MD, also professors of surgery, are helping put pieces of that puzzle together by determining what changes to the function of vascular cells are axiomatic later on infinite flight.
Schrepfer in 2016 studied the vascular systems of mice that had spent time on the ISS, equally well as vascular cells cultured in a microgravity environment on World. Her team is still analyzing their data, but so far it appears that the walls of the carotid arteries became thinner in mice in space, maybe considering the lower gravity demanded less blood pressure for circulation.
The team also found that the cultured cells showed changes in cistron expression and control that resemble changes seen in patients with cardiovascular disease on World.
While these changes might not be detrimental in the microgravity of the Space Station, on Earth they result in poor blood circulation.
"When astronauts return to Earth's gravity, muscle weakness is only role of the reason they can't stand upwards," Schrepfer said. "They also don't get enough blood to their brain, because their vessel function is impaired."
There is hope: Schrepfer and her team accept identified a small molecule that prevents vascular walls from thinning in mice. She and her team are planning to do rubber trials of that molecule on humans in the near future.
Immune System and Cell Repair
Schrepfer has also received an accolade to study effects of microgravity on the allowed system as a model of aging, both in space and after returning to World. She has a kindred spirit in Millie Hughes-Fulford, PhD, adjunct professor of medicine and the first female scientist to work in space. Hughes-Fulford tended experiments aboard the Columbia infinite shuttle in 1991, and has been investigating the changes in gene expression in T-cells in space since virtually 2003.
"Over half of the Apollo astronauts had some sort of immune trouble," she said. "And so, we knew back then that the allowed system wasn't working well in infinite."
Her current piece of work involves not only looking at cistron expression simply too at the role of microRNA (miRNA) – tiny molecules that can switch genes on or off. Her inquiry revealed five of these miRNAs, each of which controlled genes that activate T-cells, weren't working properly.
"Before this, we could say that the genes weren't existence turned on, but we didn't know why," said Hughes-Fulford. "At present we know the regulators of the genes."
These changes are the same ones seen in aging, leaving the elderly with less robust immune systems. In space, though, the changes begin to occur after 30 minutes, while in a human they may take 30 years. The research past Schrepfer and Hughes-Fulford could help people who travel in space, but besides is an opportunity to study changes that can be challenging to follow throughout decades on Earth.
On the flip side, some research is confirming that other physiological functions may endure space flight.
Fathi Karouia, PhD, a professional researcher in the UCSF School of Chemist's and scientist at NASA Ames Inquiry Middle, was involved in a report showing that the process of DNA repair – vital for an organism's long-term health – seems to be relatively unaffected by the spaceflight surround.
Karouia, who over the by three years has been office of many experiments looking at cell office in spaceflight, collaborated with Honglu Wu, PhD, of the NASA Johnson Space Center, to study fibroblast cells cultured onboard the ISS. Their investigation looked at how spaceflight, and microgravity in particular, affects the cells' response to DNA harm.
Assessing the fibroblast cells when they returned, Karouia and his colleagues saw that the infinite-exposed cells repaired their Dna as effectively as similar cells that remained on Earth.
"The story isn't clear, though," Karouia said. "Deoxyribonucleic acid repair as well depends on the cell type and growth conditions. This kind of work could help u.s.a. empathise Deoxyribonucleic acid repair processes in all cells, how some cancer cells manage to repair themselves despite dissentious radiations treatment." Ultimately, Karouia said, studies like these will help address risks of radiation during extended space flying, including the mission to Mars.
While the research into space travel's effect on the human body continues, the researchers agree that before we're able to send humans to Mars, nosotros need to know more than about what'southward required for their living surroundings to keep them live and healthy.
"The all-time manner to kill a plan is to kill the people involved in it," said Hughes-Fulford. "If nosotros're going to send spaceships to Mars, we demand to understand how to sustain the people living inside them."
Source: https://www.ucsf.edu/news/2017/07/407806/traveling-mars-will-wreak-havoc-our-bodies-can-we-prevent-it
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