The Tartan

Yet heart attacks are only one of the three most common causes of heart failure. The other two causes are coronary artery disease and high blood pressure. About 800,000 Americans suffer from a heart attack each year, and the number of individuals suffering from coronary artery disease is even higher with over 18 million cases in adults in the U.S. alone.

Patients experiencing heart failure are placed on the national transplant waiting list if they qualify. However, the amount of time they have to wait until they receive a new heart varies. The severity of illness, compatibility with the donor, and the number of donors in the area can affect how long a patient waits before receiving a transplant. An increased amount of time spent on the waiting list can contribute to an increase in transplant failure, according to the National Institutes of Health (NIH).

But new research may provide hope to those waiting for a new heart. Scientists have figured out how to engineer heart muscle grafts. In experiments performed on rhesus macaques (rhesus monkeys), researchers have been able to take somatic cells (any cell other than reproductive cells such as skin or blood cells), reprogram them into induced pluripotent stem cells (iPSCs), differentiate them into cardiomyocytes (heart muscle) and stromal (connective tissue) cells to create an engineered heart muscle (EHM) graft. This EHM graft is then implanted into the failing heart of a rhesus macaque.

The experiment demonstrated the successful remuscularization of the heart in both EHM allografts and autografts in rhesus macaques. Allografts are tissues transplanted from one individual to another within the same species. An autograft is the transplant of tissue from one part of the body to another but within the same individual. What’s more, these EHM grafts didn’t cause arrhythmias (abnormal heart rhythms), tumors, or serious complications.

The key to success lay behind the vascularization (formation of blood vessels) of the implanted EHM grafts. The heart muscle grafts won’t immediately develop blood vessels upon being implanted into the heart. It is possible that the heart muscle grafts were able to survive due to their hypoxia resistance (ability to survive with low oxygen) and anaerobic glycolysis (ability to produce energy without oxygen).

Prior research indicated that the injection of heart muscle cells into the heart could lead to electrical issues. However, such issues did not present themselves throughout the research. It was found that the EHM grafts moved in sync with the heart over time, contributing to the well-being of the heart.

With so much potential, researchers decided to begin clinical trials in humans. A 46 year-old woman who suffered a heart attack in 2016 recently became the first patient to undergo this process.

The woman underwent an operation in which 10 EHM patches made of 400 million cells were placed on the surface of her failing heart. These patches helped stabilize her long enough for her to receive a heart transplant. After the transplant, researchers found that the heart patches implanted in her heart had vascularized.

Although EHM grafts are not meant to substitute the need for a heart transplant, they can help stabilize the more than 3,000 Americans as of Sept. 2024 who are in need of one.

Of course, there is much that can be done to prevent the need for a heart transplant in the first place. There are obvious strategies like  drinking alcohol in moderation and avoiding smoking, being physically active, and getting at least 7 to 9 hours of sleep every night that can go a long way.