Researchers from the University of Liverpool’s Institute of Ageing and Chronic Disease have received over £1.1 million in funding from the UK Space Agency to send muscle tissue to the International Space Station as early as 2021. The project, titled ‘MicroAge,’ is headed by Professor Malcolm Jackson of the Centre for Integrated Research into Musculoskeletal Ageing (CIMA), and looks to elucidate why muscular degeneration occurs in old people, astronauts and even in animals. Amongst 14 different projects pitched to the UK Space Agency, only 3 received funding, so here is why this university’s bid was successful and what they are planning to do.

 

When we exercise, we build up dangerous chemicals – known as free radicals – in our muscles. In younger people, muscles can produce proteins that nullify the effects of free radicals, but as we get older we lose the ability to get rid of them. The build-up of free radicals plays a role in the weakening and breaking down of skeletal muscle, which is known as muscular atrophy, and is often seen in older populations. This break down can then lead to a condition called sarcopenia, affecting more people than we realise, as adults aged over 50 lose between 0.5-1% of their muscle mass per year.

Muscular atrophy is a side effect of ageing, but also of prolonged periods of immobilization. All of our evolution has taken place on Earth, which has led to humans having antigravity muscles, which include calf muscles, quadriceps, and the muscles on the back of our necks.  In space, however, skeletal muscle is not required to maintain posture. In response to weightlessness from lack of gravity, astronauts can lose up to 20% of their muscle mass in less than 2 weeks; to combat this, astronauts are required to exercise 2 ½ hours a day when they are on the International Space Station (ISS).

The University of Liverpool researchers, partnered with Kayser Space Ltd (a company that designs systems for space), plan to grow muscle tissue on 3D constructs inside experimental containers which are roughly the size of  an iPhone.

The 3D anchor where the muscle will grow, designed and 3D printed by PhD student Adam Janvier from the Institute of Ageing and Chronic Disease at the University of Liverpool.

A Kubik Interface Container (KIC). Containers like this will hold the 3D anchor and muscle, along with growth media.

These containers have everything necessary for the experiment to happen, including growth media for the muscle and the ability to electrically stimulate the muscle tissue. The containers will be stored within a KUBIK, an incubator on the International Space Station, which also contains a centrifuge.

Muscle constructs, within the centrifuge, will act as controls for the experiment. As the centrifuge spins at 1G, it creates a microgravity environment generating a gravitation force similar to that on Earth. The tissue samples in KUBIK will be electrically stimulated, causing the muscle tissue to contract, resembling the reaction during exercise.

An example by Vox of how muscles contract when electrically stimulated.

The researchers are looking to answer the following questions:

  1. Is the cause behind the loss of muscle mass in old people the same as in astronauts?

The researchers will be able to measure the proteins being produced by the contracting muscle in space. By comparing the proteins being produced by the muscle in KUBIK to the proteins being produced in old people, the researchers will know if the same proteins are to blame for muscular atrophy in astronauts and old people. This may also reveal drug targets to stop muscular degeneration in both groups.

  1. Does spinning the control muscle in the centrifuge stop the muscle mass from deteriorating?

By comparing the proteins being produced by the muscle tissue in KUBIK to the muscle tissue that is being spun in the KUBIK centrifuge, researchers will know if spinning the tissue is enough to stop muscular degeneration. The expectation is that the spinning tissue will act like a young person’s muscle and produce proteins that can remove free radicals, while the stationary tissue will act like an old person’s muscle and atrophy.

  1. Does the overexpression of HSP10 stop muscular degeneration of the tissue in space?

Previous studies found that a mitochondrial protein called Heat Shock Protein 10 (HSP10) could stop muscles from deteriorating in old mice. The experiment found that by making old mice produce more HSP10, the mice had less free radicals and their muscles did not degenerate. HSP10 is found in many organisms, including humans, and there is even an equivalent protein in bacteria like E. coli. The researchers will be sending both normal muscle tissue, and muscle tissue that is producing more HSP10, to the ISS. By comparing the two muscle samples, they will know if HSP10 can remove free radicals in humans and stop muscular atrophy like it does in mice. Based on the results, this could be one potential treatment for stopping muscular atrophy in both astronauts and old people.

 

The full press release by the UK Space Agency can be found here.

Special thanks to Dr. Fiona Mutter, PhD student Adam Janvier, and Professor Malcolm Jackson for their cooperation and collaboration in this article.

 

Featured image can be found here.