World's first transplant of lab-grown heart muscles

A team of scientists at Osaka University in Japan have carried out the first transplant using lab-grown heart muscle cells.

The first-of-its kind surgery was carried out as the first stage of a clinical trial at the end of January. If successful, it is hoped that this type of transplant could be used in place of full heart transplants in the future.

'I hope that (the transplant) will become a medical technology that will save as many people as possible, as I've seen many lives that I couldn't save' said project leader Yoshiki Sawa, a professor of cardiovascular surgery at Osaka University Hospital.

The pilot operation was performed on a patient suffering from ischemic cardiomyopathy, a condition caused by damage to the heart resulting from a heart attack or coronary artery disease. As a consequence, not enough blood can reach the heart due to narrowed arteries.

In severe cases, the condition might require a full heart transplant to prevent heart failure. Instead, the team transplanted a man-made sheet of heart muscle tissues onto the damaged areas of the heart. It is hoped the heart cells on the degradable sheet will grow and secrete a protein that promotes blood vessel regeneration, ultimately improving cardiac function.

In order to grow heart muscle in the lab, the researchers began with induced pluripotent stem (iPS) cells. These are made from an adult's cells, normally from skin or blood, which are reprogrammed back to their embryonic pluripotent state, which means they have the potential to become many different types of cells.

The researchers encouraged the iPS cells to become the heart muscle cells that they needed. These differentiated heart muscle cells were then placed on small sheets, just over 0.1mm thick, ready for transplantation.

The surgery is the first in a series of ten operations that will be given to patients suffering from the condition over the next three years as an initial clinical trial.

Between 4000-4500 heart transplants are made each year in the US and can cost up to $1.4 million per transplant. The requirement of a close match between donor and recipient also means that the waiting list to receive a life-saving transplant can be very long. It is estimated by the British Heart Foundation that up to 1 in 6 of individuals in the UK never receive the heart transplant they need.

If it is shown to be successful and safe, the researchers hope this approach could be used to ultimately eliminate the need for some heart transplants. Lab-grown muscle would negate the need for a suitable donor, and the likelihood of the recipient's immune system rejecting cells is much reduced compared to a whole organ.