Can we grow a heart?

I had a friend in high school, who everyday lived in fear that the immunosuppressive medication stopping her body from attacking her heart would stop working, and her heart would fail. She had a heart transplant at the age of eight after suffering from heart failure, a condition that was common in her family. She was lucky. There are currently 116,581 people in need of a lifesaving organ transplant (1), and out of the 4,000 Americans waiting for a heart transplant, only 2,500 will be transplanted each year (2).

Even if they receive a transplant, these patients will be on medication and experience multiple corrective surgeries, perhaps even multiple transplants over the course of their lifetime (3). Recently however, there is hope for another method to improve these patient’s quality of life;

What if we could grow them a new organ, a new heart, from their own cells?

This idea has been around for years and is promising, if we can accomplish it. Growing an organ with a patient’s own cells will reduce or exclude the need for immunosuppressive medication and hopefully, drastically reduce the side effects and possible need for further intervention. This is a great theory, but growing an organ is not a simple process.

A team of scientists from Massachusetts General Hospital and Harvard Medical School have gotten one step closer to this goal, using adult skin cells to regenerate functional human heart tissue. Human heart tissue has been manufactured in labs previously, however this study is unique in their methods and thus, their results.

 In this study, published in Circulation Research, experimenters took donated human hearts deemed unfit for transplant and removed the cells from the previous owner using a detergent solution. What then remained was the extracellular matrix or the “architecture” of the heart. This matrix was checked for strength, before being introduced to new cells, essentially providing the “scaffolding” the cells needed to develop. Over the course of fourteen days, nutrient solution was infused into the heart and allowed the cells to grow as if they were inside a human body. After this period, the experimental hearts showed the basic structural tissue that together resembled immature human hearts. The researchers then maintained such cardiac tissue constructs in culture for 120 days to demonstrate definitive sarcomeric structure, cell and matrix deformation, contractile force, and electrical conduction (2).  After electrical stimulation, the hearts even began to beat. While this is a large step forward in the process to create individualized hearts, researchers admit they have a long way to go (4). The next step in advancing this research is to create a more human-like environment for the cells to grow and mature, in order to create a heart suitable for a patient.

While it may take several more years before we see artificially grown hearts placed into patients, this research provides hope for all 116,581 people on the UNOS list. If science can create artificially grown hearts with the patient’s own tissue, this research could possibly translate to the artificial tissue development of other needed organs as well.

Here’s a TedTalk about tissue regeneration (it’s from 2009 but it’s good)

https://www.ted.com/talks/anthony_atala_growing_organs_engineering_tissue

(1)   https://www.unos.org/data/

(2)   http://circres.ahajournals.org/content/118/1/56

(3)   http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/CareTreatmentforCongenitalHeartDefects/Heart-Transplant_UCM_307731_Article.jsp#.WeQ8BGiPJPY

(4)   https://www.eurekalert.org/pub_releases/2016-03/mgh-fhm031116.php