Meet the Team: Prof Julie McMullen

The broad theme of my research came about because of my interest in understanding why an enlarged heart is good in some people and bad in others. The heart enlarges in elite athletes or people who exercise a lot, and this heart growth is beneficial. Conversely, the heart also enlarges in people with heart disease or heart failure, but this heart growth is bad.

My research has focused on understanding those differences at the genetic level, and we identified a gene that is critical for the beneficial heart growth that occurs with exercise – the PI3K gene.

One of the things we are trying to do is improve the heart function of people with a failing heart so they don’t get breathless and can undertake normal everyday tasks. Our goal is to mimic the beneficial effects of exercise in the failing heart by developing new drugs. This will improve heart function and reduce the risk of heart disease or heart failure, which is increasing in Australia and globally.

Showing that PI3K is critical for exercise-induced heart growth is my most recognised discovery to date. It has also led me into the other research areas. For example, we realised that when this same gene was decreased in the heart, it made it more susceptible to AF, which is now another big focus of my research.

Understanding AF is really important because once people have AF, it's incredibly hard to reverse. So my team and I are working hard to develop a simple blood test to predict when people are more susceptible.

One thing I have learnt in my career is you have to be very open to the unexpected and the serendipitous findings because some of those findings have resulted in the most key discoveries. To identify an unanswered question or knowledge gap, and undertake experiments to make a discovery that will hopefully one day make a difference, is an absolute privilege.

I remember visiting her as a young girl and helping her dispense the multiple tablets she had to take every morning, which she used to hate. She was a passionate gardener and cook, and those tasks were so much more difficult when she was breathless (a common symptom of heart failure). It’s terrible that people with heart failure, who are so mentally well, can’t do simple everyday tasks we take for granted.

Another event that impacted me early in my career was when a father contacted me because his son had died unexpectedly in his sleep. Only after the event, it was discovered their son had a heart condition they had no prior knowledge of. The boy’s parents were understandably upset and distraught. My hope is that one day we’ll find a reliable biomarker so we can identify people at risk with a routine blood test so that we can prevent these tragic events from happening. It is just so devastating for the families who experience this loss unexpectedly.

It's also alarming how many people with end stage heart failure don’t make it onto the heart transplant list or die while on the waiting list. That’s why we desperately need new therapies. Gene therapy is just one promising new approach, and with more research, treatment could be a single injection in a day clinic that lasts for months or even years.

Research provides an opportunity to give individuals a better quality of life for longer, and to prevent unexpected cardiac events or death.