"The heart needs to generate force and shorten at the same time to squeeze blood out; this is not usually something you see in in vitro heart models," Terracciano said.
Using tiny pieces of heart tissue with preserved structure and function, they were able to recapitulate the sequence of mechanical events as found in the body. This was done by creating a custom bioreactor that allows the tissue to shorten in sync with electrical stimulation. To see whether the heart tissue in their system behaved like it would inside the body, they added noradrenaline and changed the workload on the tissue to simulate normal conditions and disease. The team observed changes in force similar to those observed in hearts in vivo.
The new aspects of this system are that contraction parameters can be promptly adjusted using computer algorithms to mimic normal or disease conditions, for example, to recreate the stiffer conditions of high blood pressure.
"If you have high blood pressure, you affect how the heart cells work. We can recreate this condition to understand what happens at the level of the tissue," Terracciano said. Pitoulis added, "We now have a unique tool to study the mechanical and electrical properties of heart tissue, as well as long-term changes that happen at the molecular level within the context of healthy heart or disease."