Cosmic Cure

Space travel is hard on the human body. After a few weeks in microgravity, astronauts may begin to experience a range of symptoms including headaches, visual impairment, bone loss and muscle atrophy. Many of space flight’s biggest health risks come from spending time outside of Earth’s gravitational pull – but not all of them. “Actually, there’s an even bigger risk called space radiation,” says James Won suk Jahng (PhD ’20), a York University biology graduate who is now an instructor and researcher at Stanford University.

Overcoming space radiation will be critical for humans to be able to explore our solar system beyond Earth and the moon. Jahng’s research aims to minimize the harmful effects of cosmic rays – and it could have important applications closer to home.

On Earth, we are mostly shielded from space radiation by the magnetosphere, which blocks dangerous rays from reaching the planet’s surface. Beyond our atmosphere, astronauts are constantly bombarded by high-energy space radiation, which can damage major organ systems – notably, the cardiovascular system and nervous system – or cause cancer. The longer someone is exposed to space radiation, the greater the likelihood they will experience these negative effects.

Jahng’s lab is currently working to develop drugs that hinder space radiation damage. To do so, the researchers are giving experimental drugs to mice and then exposing them to high doses of radiation. While the types of radiation that someone might be exposed to planet-side differ from what astronauts encounter in space, “we hypothesize that there’s some common pathway that causes damage to our human body,” Jahng says.

One of the main ways radiation harms living beings is by breaking strands of DNA. These breaks can interfere with the way DNA replicates; enough breaks can even kill cells outright. In blood vessels, this leads to stiffening that mimics the effects of plaque buildup and causes heart disease. The researchers are currently investigating drugs that might help stave off DNA breakage or damage.

Future crewed missions to Mars (or beyond) will likely hinge on our ability to protect astronauts against such health impacts. And in the near future, it will be important for space exploration closer to home. Agencies including NASA are already planning to build permanent bases on the moon. Protective drugs will be crucial for anyone living on these stations for an extended period of time.

Yet, “there are many applications beyond, you know, space,” says Jahng. For example, radiation-protective drugs could be beneficial for nuclear power plant workers. They could also reduce the chances of adverse outcomes for people undergoing radiation therapy for cancer or other health conditions.

In the future, Jahng hopes to move on to drug trials with larger animal models, such as pigs, and eventually humans. And while he plans to stay in the U.S. for the time being, he hopes to have a chance to work with Canadian institutions again one day. “I’m very open to collaboration,” he says. “Especially for any collaborative project that’s relevant to Canadians.”  ■