Note: Where available, the PDF/Word icon below is provided to view the complete and fully formatted document
Disclaimer: The Parliamentary Library does not warrant or accept liability for the accuracy or usefulness of the transcripts. These are copied directly from the broadcaster's website.
How the body reacts to prolonged reduced grav -

View in ParlViewView other Segments

Theodore Orfanos: Hi, my name is Theodore Orfanos and I'm currently doing my PhD at the University of New South Wales on how microgravity affects the development of cancer. Microgravity is a significantly lower gravitational pull experienced by astronauts in space.

Space is a harsh environment which produces a number of effects on human physiology. All life on Earth has developed under a constant gravitational pull. So as you can imagine, by entering an environment which is lacking in this gravity, our bodies are affected. So what happens to human physiology when someone enters an environment with microgravity?

Astronauts in space experience loss of blood plasma, decreased number and response of T-lymphocytes, muscle degeneration due to unloading of weight-bearing muscles, and shrunken legs. They develop puffy face as a result of fluid redistribution around the body, reduced bone density, and kidney stones due to bone demineralisation, impaired wound healing, and disorientation as a result of alterations in sensory input.

As you can see, microgravity affects the musculoskeletal system, the cardiovascular system, the sensory and motor system, and the immune system. Surprisingly, cells examined after exposure to microgravity show a range of effects, including a reorganised cytoskeleton, disorganised microtubules, reduced locomotion and change in cell shape. The very structure of the cell is altered during exposure to microgravity.

With this in mind, you can see that space travel can be highly risky. If our physiology is altered so significantly after the short space missions that have taken place so far, then what will happen during an extended space mission, such as a three-year mission to Mars?

When we take into account astronauts' exposure to radiation, we have another problem on our hands; cancer. It has been determined that on a mission to Mars, astronauts would be exposed to enough radiation to generate a cancer risk. Because of this, a thorough understanding of the role of microgravity in cancer development is needed.

So far, studies looking at the overall expression of genes after exposure to microgravity have shown an increase in the expression of genes involved in cancer development, and a decrease in the expression of genes involved in the suppression of cancer. It has also been shown that the amount of a molecule involved in the inhibition of cancer, that kills off cancerous cells, is highly reduced after exposure to microgravity, and that's why I'm studying it.

You might ask how I study microgravity without access to a fully funded space program. As you can imagine, sending samples into space would be difficult, it is time-consuming and, above all, expensive. Also the G-forces experienced by the sample on re-entry may have an effect on the results. To get around this we simulate microgravity on Earth. There are few methods for doing this, but for my experiments I culture cancer cells in a NASA designed device known as a rotating wall vessel bioreactor.

The bioreactor is designed to send culture samples into a constant state of freefall, thus simulating microgravity. Microgravity can never be truly reached on Earth, but we can at least simulate the effects of it through this process. The aims of my experiments are to culture cancerous cell lines grown under conditions of both simulated microgravity and standard Earth gravity to compare their responses.

I hope that through my research we can assess any potential risk of space flight in the development of cancer and, if required, that potential treatments may be discovered.

Robyn Williams: Theodore Orfanos at the University of New South Wales.