Often times organ transplants are the only way to save someone’s life that has a failing organ. But living organs are hard to come by and waiting lists are long. Then there are the challenges with having the body accept the an external transplant.
Scientist are working on a new way to source replacement organs, bioengineering then in a lab. They have already made progress to creating bioengineered human hearts, creating functional human heart tissue. Currently it still requires using a donated heart but one that is infused with cells of the recipient.
The technique involves re-populating a decellularised organ – stripped of the original donor’s living cells – with new cardiac tissue grown from the potential recipient’s induced pluripotent stem cells (iPSCs). In effect, the donor heart is stripped of the components that would trigger an immune response from the recipient, and is replaced with the recipient’s’ own cardiac muscle cells.
“Regenerating a whole heart is most certainly a long-term goal that is several years away, so we are currently working on engineering a functional myocardial patch that could replace cardiac tissue damaged due [to] a heart attack or heart failure,” said researcher Jacques Guyette from the Massachusetts General Hospital Centre for Regenerative Medicine (CRM).
Harald Ott was the lead surgeon and documented the study in Circulation Research. Ott previously developed a decellularisation procedure to strip living cells from rat organs with a detergent solution, then repopulated with organ-appropriate grown cells. In his this new study, the multi-stage process was conducted on human hearts for the first time.
“Generating functional cardiac tissue involves meeting several challenges,” said Guyette. “These include providing a structural scaffold that is able to support cardiac function, a supply of specialised cardiac cells, and a supportive environment in which cells can repopulate the scaffold to form mature tissue capable of handling complex cardiac functions.”
The study used 73 human hearts authorised for scientific research. The researchers induced pluripotent cells to differentiate into 500 million cardiac muscle cells. They then seeded those cells into the tissue of the decellurised hearts.
The cardiac muscle cells started spontaneously contracting. The researchers say this represents the first regeneration of human heart tissue from pluripotent stem cells. The beating organs were then mounted in a automator bioreactor system that provides the muscle with a nutrient solution and simulates other conditions of a living heart.
“Among the next steps that we are pursuing are improving methods to generate even more cardiac cells – recellularising a whole heart would take tens of billions – optimising bioreactor-based culture techniques to improve the maturation and function of engineered cardiac tissue, and electronically integrating regenerated tissue to function within the recipient’s heart,” said Guyette.
