Scientists Succeed In Growing A Beating Human Heart From Stem Cells

Thousands of Americans need heart transplants each year.

Scientists from Massachusetts General Hospital and Harvard Medical school have successfully grown a human heart from adult skin cells, according to a study published in Circulation Research.  

The breakthrough could be huge news for the 4,000 Americans currently awaiting heart transplants, and the more than 25 million people who suffer heart failure each year. In the United States, approximately 2,500 of the 4,000 people in line for heart transplants actually receive them, indicating a shortage that research like this might be able to address.


According to the journal, the scientists took 73 donor hearts deemed unfit for transplantation, stripped away cells on those hearts and replaced them with skin cells that — using messenger RNA — had been turned into pluripotent stem cells, the kinds of cells that can be specialized to any part of the human body. After causing the stem cells to develop into two types of cardiac cells, the researchers then mimicked the environment a human heart would typically grow within and infused the cardiac cells with a nutrient solution that facilitated growth.

After two weeks, they shocked the hearts with electricity, and lo and behold, the hearts began beating. The tissue inside appeared to be well-structured and functional. Popular Science compared the growth of the heart as "building a house with the frame already constructed." 

Ultimately, the researchers aim to grow an entire human heart that is capable of being transplanted. 

"To show that functional myocardial tissue of human scale can be built on this platform, we then partially recellularized human whole-heart scaffolds with human induced pluripotent stem cell–derived cardiomyocytes," the team of scientists wrote in their journal. "Under biomimetic culture, the seeded constructs developed force-generating human myocardial tissue and showed electrical conductivity, left ventricular pressure development, and metabolic function."

The technological development was celebrated on social media. As one user wrote: "Living in the future is awesome."

Cover photo: Shutterstock / Africa Studio.


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