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Cardiac Stem Cells
Cardiac Stem Cells
There’s a sad fact about survivors of childhood cancer that doesn’t sit well with stem cell researcher David Elliott.
While survival rates for children with cancer following treatment are now almost 90 per cent, drug regimes like chemotherapy can be toxic to the body’s organs. Chemotherapy patients are nine times more likely than the general population to die of heart failure.
It’s a frightening statistic for someone of any age. But for a child, it’s inconceivable. “It’s not okay if you are five,” says David, himself a father of three young children. “There’s a lot of life to go.”
This can come as a shocking revelation to parents after the family has endured a painful journey to rid their child of cancer.
“It’s another stress on the family,” says David. “We’ve been able to treat the cancer, but they’ve still got this ongoing issue.”
Damage to the heart from chemotherapy is known as cardiotoxicity and it’s an unwelcome hurdle after recovery from cancer. This is why chemotherapy patients need to get their heart checked annually after treatment stops.
About 30 per cent of people who undergo chemotherapy are at risk of cardiotoxicity. The problem is there is no way of predicting who is susceptible, or who may be resistant. That’s where David Elliott and his team come in.
David and his colleagues, Professor Andrew Elefanty and Professor Ed Stanley moved their lab from Monash University to Murdoch Children's in 2012 to continue their stem cell research alongside clinical patients and medical practitioners.
In one particular study led by David and clinician scientist, Dr Rachel Conyers, the records of 400 children who have undergone chemotherapy in the past five years are being analysed. Of those, 17 developed severe cardiac problems in the first year after the treatment. Another 64 experienced some degree of compromised function while the rest were unaffected.
In 2016, as part of the study, patients will undergo genetic screening. Stem cells from the 17 most severely affected children will be compared to stem cells of unaffected patients, to understand what it is genetically that makes patients either resistant or susceptible to heart problems after chemotherapy.
“We hope to identify some genetic changes that we can quickly screen for before people start chemotherapy,” David says.
It’s a sign of the rapid pace at which stem cell research is moving, in the direction of personalised medicine.
David and his team are also undertaking broader research to understand heart development and heart disease, to underpin the cardiotoxicity study.
“We’ve got to understand what it takes to make a heart that sits comfortably in your chest and beats two to three billion times in your life. How do you make that robust sort of beast? And the other thing is, what happens when something goes wrong?” says David.
In the lab, where pop music provides a cheerful soundtrack for scientists peering down microscopes, stem cells derived from samples of blood or skin are the starting point.
The induced pluripotent stem cells can be used to make any cell in the body. In this lab, they are turned into cardiomyocytes – a heart muscle cell that generates the cardiac force to make the organ pump blood around the body. Amazingly, under the microscope, these cardiomyocytes visibly pulsate.
While the cardiotoxicity research is among the most important of David’s career, he is lesser known for a more obscure finding – that hearts evolved only once from a common ancestor six hundred million years ago – in a study examining the heart development genes in gastropods including octopus, squids and cuttlefish. The finding made the cover of the prestigious scientific journal, Development.
Joining the Murdoch Children's is a recent career turning point. “We touch wood every day. We love it,” says David. “This is a brilliant place, absolutely brilliant.
“There is a lot of enthusiasm and a lot of support here. You can go and talk to the oncologist or the cardiologist so you get a feeling for their patient load and the problems they want addressed. It makes it much more rewarding to work in this setting.”