Most body cells have one particular function. An epithelial cell makes up the skin, and an endocardial cell makes up the heart. However, one type of master cell can differentiate itself into all these organs and more during embryonic development. Scientist call them pluripotent stem cells.
These stem cells are triggered by cell signaling that decides which particular type of cell they differentiate into. A process that researchers were able to use to produce mini hearts.
Recently, researchers from the Austrian Academy of Sciences in Vienna grew minuscule heart models from pluripotent stem cells. These models, called cardioids, are the size of a sesame seed.
While researchers have previously been able to manually construct such organs through tissue engineering, these cardioids did not need anyone’s help. They are self-organizing. They group together in response to embryonic cell signaling to form a hollow, heart like organ that can contract rhythmically to eject liquid out of its cavity – just like a real heart. And the entire grouping process only took a week.
“Self-organization is how nature makes snowflake crystals or birds behave in a flock. This is difficult to engineer because there seems to be no plan, but still something very ordered and robust comes out,” said Sasha Mendjan, biologist and part of the research team. “The self-organization of organs is much more dynamic, and a lot is going on that we do not understand. We think that this ‘hidden magic’ of development, the stuff we do not yet know about, is the reason why currently diseases are not modeled very well.”
Why do we need a mini heart?
The researchers predict that these cardioid models will help scientist understand congenital heart diseases more thoroughly to save new-borns lives.
“We want to come up with human heart models that develop more naturally and are therefore predictive of disease,” said Mendjan . “This way, companies will be more open to bringing more drugs into the clinical trials because they are much more certain of the outcome of the trial.”
They also tested the model’s ability to regenerate tissue like living tissue. They froze parts of cardioids with cold steel rods to discover that some tissue indeed died. Finally, fibroblastic cells appeared at the wound to start the healing process.