Scientists Grow a Heart

From Minnesota Public Radio, here’s a startling story. University of Minnesota scientists have, for the first time, grown a beating heart in a laboratory.

The scientists didn’t start completely from scratch. Instead, they used a process called whole organ decellularization to strip cadaver rat and pig hearts of everything but the extracellular matrix, the framework between the cells. What remained was a snow white shell, which lead researcher Doris Taylor compared to the gristle on a steak. They then seeded that framework with progenitor cells harvested from newborn rats and pigs, and then placed the combination in a sterile setting to see what would happen.

Four days later, when pacemakers used to stimulate the heart tissue, it began contracting, and within eight days, the hearts were pumping.

"Take a section of this 'new heart' and slice it, and cells are back in there," Science Daily quoted Taylor as saying. "The cells have many of the markers we associate with the heart and seem to know how to behave like heart tissue."

"We just took nature's own building blocks to build a new organ," co-investigator Dr. Harald C. Ott explained. "When we saw the first contractions, we were speechless."

While the heart-building business is still in its earliest stages, the researchers are optimistic that eventually it will be possible to grow a fully functioning human heart for transplantation from the recipient’s own cells. Such a breakthrough might save the lives of the 50,000 people who die each year as they await a suitable donor heart.

"Going forward, our goal is to use a patient’s stem cells to build a new heart," Taylor said.

Recipients of hearts grown from their own cells would stand a better chance of survival than heart transplant patients do today, because they would not have to rely upon immunosuppressive drugs to keep their bodies from rejecting the new organ. The drugs have the drawback of making the patients more vulnerable to infections, liver and kidney problems, and hypertension.