For the first time, researchers have successfully transplanted heart muscles into people and only into the damaged parts of the heart. If the rest of the procedure goes according to plan, this practice may make complete heart transplantation unnecessary in some patients.
Japanese researchers from Osaka University successfully performed the first laboratory-grown heart muscle transplantation, the Japan Times reported on January 28th. Instead of replacing the patient’s entire heart, they placed biodegradable sheets of myocardial cells over the impaired areas of the heart. If the procedure goes smoothly, this practice may become widespread and ultimately make complete heart transplantation unnecessary in many patients.
To cultivate the myocardial cells in the laboratory, the Japanese scientists used induced pluripotent stem cells (iPS) from the patient’s own body. By reprogramming them, they convert them into myocardial cells and place them in thin, biodegradable plates. By secreting a protein, the cells should help regenerate the blood vessels and improve the patient’s heart function. If all goes well, this should lead to enough regeneration of the damaged heart to prevent total heart transplantation.
The Japanese scientists now plan to monitor the patient for a year and hope to eventually perform the same procedure on another nine people in the next three years. If the clinical trials go well, the scientists are expected to get the approval of the Ministry of Health for the procedure as soon as possible. The procedure may become a common alternative to heart transplants.
“I’ve met a lot of patients I couldn’t save.”
It’s much easier to get iPS cells than to find a compatible donor heart. In addition, a patient’s immune system tolerates more stem cells than a new organ, researchers explain. “I hope [stem cell transplantation] becomes a medical technology that saves as many people as possible, because I’ve met a lot of patients that I couldn’t save,” Professor Yoshiki Sawa, who led the study, told the Japanese press.
The patient who benefited from this medical discovery suffered from ischemic cardiomyopathy. This heart disease, which affects about 5% of the population in the US and especially men, is characterized by insufficient oxygen supply of the heart due to the narrowing of the coronary arteries by atheromatic plaques (fat deposits on the vascular walls).
If a person has heart failure, he or she can be offered heart transplantation. However, not everyone can be transplanted, such as people over the age of 65, patients with active or recent cancers, and patients with certain kidney and liver problems.
2500 heart transplants per year in the US
If the patient is eligible for a transplant, he or she will be placed on the transplant waiting list. He or she must then remain available 24 hours a day and be able to reach the hospital within two hours of the call when an organ becomes available. The waiting time varies greatly: the match between donor and recipient is made on the basis of the recipient’s severity, blood group compatibility, morphology, and age. This matching is carried out by the U.S. Department of Health and Human Services (DHHS).
The operation lasts 4 to 8 hours, after which the transplanted person remains in intensive care for between 10 and 15 days, isolated to prevent any infectious complications.
Once discharged from the hospital, the patient can return to a normal life with a healthy, functional heart. However, he or she will need to take anti-rejection medications for the rest of his or her life to reduce the risks of rejection. In the US, around 2500 people receive heart transplants every year.