Lab-Grown 'Tiny Hearts' Offer New Hope for Heart Disease Patients

Scientists at QIMR Berghofer's Cardiac Bioengineering Laboratory have pioneered the development of lab-grown, three-dimensional heart tissues called cardiac organoids. These organoids are designed to mimic the structure and function of adult human heart muscle, providing a groundbreaking tool for studying heart diseases.

The process involves using human pluripotent stem cells, which have the potential to become any cell type in the body. Normally, when these stem cells differentiate into heart cells, they resemble those found in a developing fetus, which limits their effectiveness for modeling adult heart conditions. However, the researchers activated specific biological pathways that simulate the effects of exercise, significantly advancing the maturity of these cells and making them behave more like genuine adult heart tissue.

This breakthrough allows scientists to utilize these lab-grown hearts to test new drugs aimed at treating heart diseases. The organoids, which can be as small as a chia seed, facilitate rapid screening of multiple compounds, accelerating drug development processes.

Furthermore, the team successfully modeled genetic heart disorders caused by mutations in genes like ryanodine, calsequestrin, and desmoplakin. Notably, they recreated key features of desmoplakin cardiomyopathy, a condition that has been challenging to study previously.

Professor James Hudson highlighted the significance of this innovation, stating that these tiny hearts could revolutionize how heart diseases are researched and treated. In experiments with these organoids, scientists observed disease characteristics such as scarring and reduced pumping efficiency, similar to patient symptoms. They also tested a new drug class called bromodomain and extra-terminal protein inhibitors, which improved the function of the cardiac tissue.

Collaboration with Murdoch Children's Research Institute and The Royal Children's Hospital contributed to the advanced analysis of gene and protein patterns and modeling of childhood heart conditions using samples from the Melbourne Children's Heart Tissue Bank. Associate Professor Richard Mills emphasized that this approach offers a more precise way to understand and develop treatments for pediatric heart diseases, potentially benefiting some of the most vulnerable patients.

This research, published in Nature Cardiovascular Research, exemplifies how innovative tissue engineering and genetic modeling can pave the way for rapid, effective development of therapies for heart disease, ultimately improving outcomes for both children and adults.

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