Space Mighty Mice Could Protect Muscles & Bones Of Astronauts
Genetically enhanced “mighty mice” that were a part of a heath experiment on the International space Station (ISS) have shown that blocking a molecular signaling pathway can protect against muscle & bone density loss in absence of gravity.
The new study also revealed this treatment promoted the recovery of muscle & bone mass once the mice returned to Earth.
The results are promising to researchers because they might be wont to develop therapies which may help astronauts mitigate the muscle & bone loss they experience during long-term spaceflight.
Targeting this pathway could even be wont to help people on Earth who experience muscle & bone loss thanks to various conditions like dystrophy , osteoporosis & diseases that cause muscle wasting like cancer, heart condition , sepsis & AIDS.
The study published Monday in journal Proceedings of the National Academy of Sciences. NASA astronauts Drew Morgan, Christina Koch & Jessica Meir, who participated within the experiment while it had been on the space station , are included as authors and investigators on the study.
Mice in space
The 40 female mice, provided by the nonprofit Jackson Laboratory in Maine, were genetically manipulated for muscle growth in an experiment to understand how zero gravity affects the physical body .
They launched & received at space platform in December and splashed down in SpaceX Dragon Capsule on Jan 7 within the Pacific .
The larger mouse during this picture has been genetically modified to lack myostatin and, as a result, has larger muscles.
The SpaceX Cargo Vehicles are unique therein they will bring new materials & experiments to the space station and return to Earth 30 days later. This suggests that samples are often returned to the ground in timely manner, which enabled the live mice to be returned to Earth, said Morgan, who also serve as emergency physician with the United States Army.
These mice are only one of the many groups of rodents that have flown on the space station over the years in name of research.
The experiment was called Rodent Research-19, and it had been wont to study both myostation & activin, which are the molecular signaling pathways which will influence & regulate bone density and striated muscle mass, acc. to NASA. These pathways, researchers believe, might be targets to stop muscle and bone loss during missions and help with recovery efforts once astronauts return to Earth.
While on the space station , a number of the mice were treated with an agent, the ACVR2B receptor, that really blocked the pathways to ascertain how it impacted their bone & muscle loss. Blocking these pathways has also been known to induce muscle & bone growth.
Because a number of these mice were genetically engineered to lack myostatin, that they had twice the typical avg. muscle mass — hence, the nickname “mighty mice.”
A size comparison shows the genetically modified mouse compared with a daily wild mouse. The mice who flew on the space station were compared with an control group of 40 female mice who remained on Earth.
The mice in space and on Earth that received the receptor treatment largely maintained and even increased their muscle & bone mass as compared with the untreated mice. Meanwhile, the untreated mice experienced significant muscle & bone mass loss.
After returning to Earth, mice receiving the receptor treatment also showed an enhanced recovery of muscle mass. This was compared with the control mice that weren’t given the treatment upon returning to Earth.
“Mice that were hypermuscular as a results of having a mutation in myostatin gene were ready to retain most, if not all, of that extra muscle during spaceflight,” said study authors Se-Jin Lee & Emily L. Germain-Lee in an email.
“These findings show that blocking the activities of those hormones does work to reinforce both muscle & bone even when mice are unable in touch weight.”
Dr. Lee may be a professor at The Jackson Laboratory & presidential distinguished professor at the University of Connecticut’s School of Medicine. Dr. Germain-Lee may be a pediatric endocrinologist at Connecticut Children’s center and a professor of pediatrics at the University of Connecticut’s School of Medicine .
This chart compares microCT images of femurs & vertebrae of treated and untreated mice exposed to lack of gravity in space.
“One thing that we found somewhat surprising is how resilient mice are even when subjected to all or any of the stresses related to space-travel ,” they said. “We knew that mice had been sent to space in past, but we still found it remarkable that after spending a month at the ISS, they appeared to resume normal activity very quickly after returning to Earth.”
Helping humans adapt
Astronauts on the space station exercise a day to mitigate muscle & bone loss, but experiments like this will help scientists understand how the loss occurs and establish better ways to manage it.
The exercise countermeasures astronauts use, which include 2 hours of resistance training & cardiovascular workouts, might not always be possible during long-term spaceflight.
“The potential for a drug treatment that would prevent (bone & muscle loss) shows tons of promise in long-duration spaceflight,” Morgan said.
But there are potential side effects that require to be considered and understood, the researchers said.
“Although myostatin’s major role is to manage muscle growth, a drug that targets other hormones besides just myostatin can affect other tissues besides muscle,” the researchers said.
The doctors cited an Ex. including Acceleron, a biotechnology company, which used its version of this receptor in clinical trials to treat patients with Duchenne muscular dystrophy . A number of the patients experienced nosebleeds, but the rationale for that’s not entirely understood. But it sheds light on the very fact that these receptors can block other things beyond myostatin.
“The challenge moving forward are going to be to know the explanations for this and other effects with the goal of deciding the way to modify these drugs to avoid such problems,” the researchers said.
The study has revealed new questions for the researchers. Going forward, they need to better understand the changes caused by microgravity in blood, muscle & bone. They also want to think about the way to conduct further investigation on a future space mission.
“Our hope is that this might be used both for astronauts during extended space travel and for people on Earth affected from muscle & bone loss,” the doctors said. “There still tons of work that might got to be wiped out on this regard, but we believe that this sort of strategy holds promise.
“We would really like to figure out deciding ways to engineer better drug candidates which may avoid a number of the potential side effects. Only by understanding the underlying science will we be ready to attempt to translate this work into new medical treatments.”
Astronauts themselves also are the basis for understanding how the space environment can affect humans.
Koch & Morgan both participated in extended stays on the station, with Koch spending 11 months aboard & Morgan staying for 9 months. Currently, astronauts typically spend about 6 months on the space platform , but some like Scott Kelly have stayed for nearly a year to check how the physical body reacts to long-term spaceflght.
These health studies might be applied to future long-term spaceflight as NASA looks ahead with the Artemis program, which aims to return humans to the moon in 2024 and will eventually land them on Mars.