Tag: bone loss

Centrifuge research on ISS suggests some artificial gravity can mitigate negative effects of weightlessness

1:30 pm

Two of the three centrifuges on ISS

When I appeared on the Space Show last month I stated something about centrifuge research that was wrong. I had been under the false impression that no such research had yet been done on ISS, and our only data came from one experiment performed by the Soviets on one of their early space stations decades ago.

Charles Lurio, who writes the very respected Lurio Report newsletter on space matters, called me afterward to correct me, and then followed up by sending me a link to a paper describing research on ISS in the past few years using rats inside three different small centrifuges (two of which are shown in the picture to the right). For this information I thank him.

You can download the paper here [pdf]. The research is significant because it suggests that the medical problems of weightlessness can be solved by creating an artificial gravity far less the Earth’s 1g environment. From the paper’s abstract:
» Read more

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New research confirms long term bone loss during long missions in weightlessness

9:46 am

According to new research done on ISS, scientists have confirmed what Soviet-era scientists had learned back in the 20th century, that long term bone loss during long missions in weightlessness can take many months to recover once back on Earth.

The bone density lost by astronauts was equivalent to how much they would shed in several decades if they were back on Earth, said study co-author Dr Steven Boyd, of Canada’s University of Calgary and director of the McCaig Institute for Bone and Joint Health.

The researchers found that the shinbone density of nine of the astronauts had not fully recovered after a year on Earth – and they were still lacking about a decade’s worth of bone mass. The astronauts who went on the longest missions, which ranged from four to seven months on the ISS, were the slowest to recover. “The longer you spend in space, the more bone you lose,” Boyd said.

The study also confirmed that some exercises in space helped to mitigate the bone loss, which ranged from 1% to 2% per month. No exercises prevented it however.

For missions to Mars, the bone loss appears less of an issue than the loss of muscle strength. Even with extensive bone loss after six months to a year in space astronauts do not notice this loss when returning to Earth gravity. They will certainly not notice it on Mars, with a gravity field 39% that of Earth’s.

More concerning is the loss of muscle strength during long missions in weightlessness. After six months to a year in weightlessness astronauts struggle on Earth to walk after first landing. This is why they are helped immediately placed to chairs upon return. On Mars no such help will be available.

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Injected stem cells cure osteoporosis in mice

9:22 am

Scientists have discovered that an injection of stem cells into mice with osteoporosis was able to completely cure them of the bone disease.

Researchers at the University of Toronto and The Ottawa Hospital had previously found a causal effect between mice developing age-related osteoporosis and a deficiency in mesenchymal stem cells (MSCs). One of the promising attributes of MSCs is that, while they can grow into different cells in the body just like other stem cells, they can be transplanted without the need for a match. “We reasoned that if defective MSCs are responsible for osteoporosis, transplantation of healthy MSCs should be able to prevent or treat osteoporosis,” says William Stanford, senior scientist at The Ottawa Hospital and Professor at the University of Ottawa.

To put this reasoning to the test, the scientists injected MSCs into mice with the condition. Six months later, which is one quarter of the life span of the animal, they observed a healthy functional bone in place of the damaged one. “We had hoped for a general increase in bone health,” says John E. Davies, co-author of the study. “But the huge surprise was to find that the exquisite inner ‘coral-like’ architecture of the bone structure of the injected animals – which is severely compromised in osteoporosis – was restored to normal.”

The importance of this discovery for space travel is that it might eventually allow scientists to use it to somehow prevent the loss of bone density during weightlessness.

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Using fish to study bone loss in weightlessness

9:04 pm

A Japanese experiment on ISS, comparing the development of fish in weightlessness with those on the ground, has provided` scientists more information about bone density loss in weightlessness.

Akira Kudo at Tokyo Institute of Technology, together with scientists across Japan, have shown that medaka fish reared on the International Space Station for 56 days experienced increased osteoclast activity – bone cells involved in the re-absorption of bone tissue – likely leading to a subsequent reduction of bone density. They also found several genes that were upregulated in the fish during the space mission. The team generated fish with osteoclasts that emit a fluorescent signal. They sent 24 fish into space as juveniles, and monitored their development for 56 days under microgravity. The results were compared with a fish control group kept on Earth.

Kudo and his team found that bone mineral density in the pharyngeal bone (the jaw bone at the back of the throat) and the teeth of the fish reduced significantly, with decreased calcification by day 56 compared with the control group. This thinning of bone was accompanied by an increase in the volume and activity of osteoclasts. The team conducted whole transcriptome analysis of the fish jaws, and uncovered two strongly upregulated genes (fkbp5 and ddit4), together with 15 other mitochondria-related genes whose expression was also enhanced. Reduced movement under microgravity also has an influence. The fish began to exhibit unusual behavior towards the latter stages of their stay in space, showing motionless at day 47.

What the data mostly confirms is that long-term weightlessness is a bad thing for the development of bones, and not just in humans. Whether scientists can use these results to counter these harmful effects is not clear, however.

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Data from an experiment on Lunar Reconnaissance Orbiter has confirmed that light plastics can provide sufficient protection for humans against radiation.

11:45 am

Data from an experiment on Lunar Reconnaissance Orbiter has confirmed that light plastics can provide sufficient protection for humans against radiation.

This is very good news indeed. Combined with the data from Curiosity, which indicated that the radiation levels in interplanetary space were less intense that expected, it appears that radiation will not be a serious obstacle to interplanetary travel.

Now we just have to get the bone loss and vision problems solved.

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NASA today announced that recent research on ISS into bone loss due to weightlessness has found that proper exercise and diet can stabilize bone loss.

11:42 am

Good news! NASA today announced that recent research on ISS into bone loss due to weightlessness has found that proper exercise and diet can stabilize bone loss.

Past Russian research on Mir had found that exercise and diet could limit the bone loss, but not stop it entirely. The key difference in this recent work seems to be the use of more sophisticated exercise equipment.

If this research holds up, it eliminates one of the most serious obstacles to interplanetary travel.

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Over-the-counter osteoporosis drug appears to keep astronauts from losing bone density on long space flights

10:14 am

Big news: New research on ISS now shows that the standard over-the-counter osteoporosis drugs used by millions on Earth appears to keep astronauts from losing bone density during long space flights.

Beginning in 2009, the group administered the drug to five long-stay astronauts on the International Space Station (ISS), including Koichi Wakata, 48, and Soichi Noguchi, 46. The five took the drug — an over-the-counter bisphosphonate used to treat osteoporosis — once a week starting three weeks before they lifted off until they returned to Earth. The researchers then monitored the astronauts’ bone mass over time and compared the results to those for 14 astronauts that had never taken the drug.

The results showed that the 14 who had never taken the drug had average bone density loss of 7 percent in the femur, and 5 percent in the hip bone. The five astronauts on bisphosphonate, however, only had average bone density loss in the femur of 1 percent, and even a 3 percent increase in the hip bone. Calcium levels in their urine, which rise the more bone mass is lost, were also very low.

If these results hold up, they might very well solve one of the biggest challenges faced by any interplanetary traveler. Up until now, bone loss during long weightless missions never seemed to average less than 0.5 percent per month. After spending three years going to and from Mars, an astronaut could thus lose about almost 20 percent of their bone mass in their weight-bearing bones, and would probably be unable to return to Earth.

Thus, a mission to Mars seemed impossible, unless we could build a ship with some form of artificial gravity, an engineering challenge we don’t yet have the capability to achieve.

If these already tested drugs can eliminate this problem, then the solar system is finally open to us all. All that has to happen now is to do some one to two year manned missions on ISS to test the drugs effectiveness for these long periods of weightlessness.

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