A method doubles the number of hearts viable for transplantation

A discovery by researchers at the Mayo Clinic and the University of Michigan could revolutionize the process of preserving hearts for transplants, significantly increasing the availability of viable organs and offering new hope to thousands of patients on the waiting list.

In a study published in Nature Cardiovascular Research , the team led by Mayo Clinic cardiac surgeon Paul Tang identified a molecular process that contributes to the deterioration of donor hearts during cold storage, an essential technique for their transport. This damage, which reduces the effectiveness of the transplanted organ, could be prevented with an existing drug: canrenone.

Currently, less than half of donated hearts are used in transplants because the safe window for their use is very limited. Cold storage, although useful for reducing tissue metabolism, can induce cellular changes that impair the heart's ability to pump blood efficiently after transplantation. One of the main resulting problems is primary graft dysfunction , present in up to 20% of cases, which can seriously compromise patient survival.

The researchers focused on the mineralocorticoid receptor (MR), a protein that responds to cellular stress. During cold storage, these receptors clump together within the cell nucleus in a process known as liquid-liquid phase separation, triggering inflammation and cell death. This phenomenon impairs the heart's pumping capacity, reducing its viability for transplantation.

To counteract this effect, the team treated donated hearts with canrenone, a drug used for hypertension and chronic heart failure. The results were remarkable: the treated hearts tripled their pumping capacity, improved blood flow, and showed less cellular damage compared to untreated hearts, even after exceeding the traditional preservation limit.

"As a cardiovascular surgeon, I've seen how each additional hour of preservation can affect the functional recovery of the transplanted heart. This finding could radically change that picture," Tang says.

In addition to the heart, the researchers observed a similar molecular pattern in other organs such as the liver, lungs, and kidneys, suggesting that this strategy could be applied to improve the preservation of multiple solid organs.

"This is a breakthrough that not only improves patient outcomes but could also extend the distance and time it takes to transport organs, making them easier to access in more remote regions," explains Eugene Chen, co-author of the study.

With these results, the team hopes to accelerate the development of new biotechnologies that allow for real-time determination of the condition and viability of organs during storage, marking a turning point in the field of transplant medicine.