Researchers have for the first time successfully grown a human heart muscle that shows typical signs of human heart function in less than four weeks using stem cells.

In a first, biomedical engineers grew human heart muscle from stem cells that showed critical hallmarks of adult human heart function, an advance that would help make drug development significantly faster, safer and cheaper. The adult-like human heart muscle was developed in just four weeks time in the lab from blood-derived human induced pluripotent stem cells (iPSCs), over only four weeks. The researchers from the Columbia University, essentially compressed the timeframe for development, which normally takes nine months, into a faster and more complete transition to cardiac maturity.

"Human cardiac tissues grown in the lab that displays the behaviour of native heart muscle would be transformative for biomedical research," said Gordana Vunjak-Novakovic, Biomedical Engineering Professor at the varsity. "To reach this goal, we forced the cultured heart muscle to go through the foetal-to-postnatal transition by an accelerated development. This was done by using early-stage iPS-CMs and increasing the frequency of electrically induced contractions, little by little, every day. "The tissues responded, and displayed adult-like gene expression, remarkably organised ultrastructure, and a number of functional features seen in the mature heart muscle, after only four weeks of culture," Vunjak-Novakovic explained.

In the study, published in the journal Nature, the team found that the longer they waited to introduce physical stimuli such as electric current and mechanical stimulation to the iPSCs, the less responsive the cells were. The team reasoned that the earlier they introduced electromechanical stimuli, the greater the effect would be. "The resulting engineered tissue is truly unprecedented in its similarity to functioning human tissue," said Seila Selimovic, Director of the National Institute of Biomedical Imaging and Bioengineering (NIBIB) Tissue Chips program. "The ability to develop mature cardiac tissue in such a short time is an important step in moving us closer to having reliable human tissue models for drug testing," Selimovic noted.