A groundbreaking collaboration between QIMR Berghofer, Murdoch Children’s Research Institute (MCRI), and The Royal Children’s Hospital is bringing us closer to understanding and treating devastating heart disease - especially those affecting children.
Scientists from QIMR Berghofer’s Cardiac Bioengineering Lab have developed lab-grown, three-dimensional heart tissues known as cardiac organoids that mimic the structure and function of real adult human heart muscle. To create these tissues the researchers use special cells called human pluripotent stem cells (which can turn into any cell in the body). However, when these stem cells become heart cells, they usually stay immature and more like the heart tissue found in a developing baby. This immaturity can limit their usefulness to model diseases that present in childhood or as an adult.
In the study, researchers activated two key biological pathways to mimic the effects of exercise and mature these cells, making them behave more like genuine adult heart tissue. This breakthrough means scientists can now use these lab-grown heart tissues to test new drugs that could help people with heart conditions. The findings have been published in the journal Nature Cardiovascular Research.
QIMR Berghofer’s Professor James Hudson says the tiny hearts may be the size of a chia seed, but offer a platform to discover new treatments. “There’s huge benefit to studying heart diseases in this way. Using human cardiac organoids allows us to screen many more compounds, speeding up the process of drug development.”
The researchers also modelled types of heart disease caused by certain genetic changes (mutations) in genes called ryanodine, calsequestrin, and desmoplakin. In particular, Desmoplakin cardiomyopathy has traditionally been hard to study, however the team was able to recreate key features of the disease using the new lab-grown heart tissues.
Professor Hudson says the results are promising on several levels. “In the cardiac organoids, the disease caused scarring (fibrosis) and made the tissue pump less effectively—similar to what happens in patients heart disease. We then tested a new type of drug called a ‘bromodomain and extra-terminal protein inhibitor’, and found this medication improved the heart tissue’s function.”
Murdoch Children’s Research Institute and The Royal Children’s Hospital played a key part in the research by using advanced gene and protein analysis, and modelling heart disease by using samples from the Melbourne Children’s Heart Tissue Bank.
MCRI’s Associate Professor Richard Mills says the findings will speed up the process of identifying treatments to improve heart function. “Our approach allows us to more accurately model childhood heart conditions, to ultimately find better treatments for some of the sickest people in our community. The collaboration with QIMR Berghofer and The Royal Children’s Hospital is accelerating progress towards these goals, and this approach has the potential to be used across a whole spectrum of childhood heart disease.”
The researchers would like to acknowledge the support of the Snow Medical Research Foundation and the Novo Nordisk Foundation Center for Stem Cell Medicine.