Bay Area Scientists Develop Mini Human Heart Chamber in a Dish

Bay Area scientists have developed a new method to test drugs that are likely to be dangerous for pregnant women and cause heart defects in the fetus.

Researchers from UC Berkeley and the Gladstone Institutes, an affiliate of the University of California, San Francisco, grew beating heart tissue from stem cells -- essentially a mini human heart chamber in a dish. Stem cells have the potential to become any type of cell in the human body.

The researchers intend to use the system to screen medications intended for pregnant women to detect whether they will likely do any harm to the fetus. Among the most commonly-reported birth defects involve the heart.

Birth defects affect three percent of babies born in the United States every year, according to the Centers for Disease Control and Prevention. Birth defects are one of the most common causes of infant deaths.

[Watch the video below for a demo.]

In 2014, scientists in the UK developed a similar model to convert skin cells into beating heart cells in a petri dish. Previously, doctors would have needed to surgically remove heart tissue from patients to test new treatments, which is invasive and not practical.

It's still early days for the technology, but the Gladstone Institutes' Dr. Bruce Conklin said the researchers have already tested whether the system could detect any problems with the drug Thalidomide. Thalidomide was prescribed widely in the 1960s for morning sickness but was later withdrawn for causing thousands of birth defects.

The system proved effective in this early experiment. Normal doses of the drug led to myriad problems, such as lower heart beat rate, compared with heart tissue that had not been exposed to the drug.

"Thalidomide was tested in animals," said Dr. Conklin, whose research specializes in human genetics that lead to cardiovascular diseases. "If they had a human model system in the 1960s, they could have caught it."

Since the Thalidomide disaster, Dr. Conklin said it has been very difficult for pharmaceutical companies to get drugs approved for pregnant women. "They are so cautious," he said. But artificially grown, in vitro, miniature organs -- known as "organoids" -- could prove effective as a means to test drugs for potential birth defects.

The researchers say that this technology may replace animal models. Today, researchers will dissect animals at different stages of development to study how organs form. But one of the many drawbacks to testing on animals is that a mouse or pig may respond differently to a drug than a human subject.

In the future, the researchers say the technology can be adapted to other human organs. Dr. Conklin said he expects that a similar model will benefit cancer patients, who experience cardiac issues as a side effect of medication.

The results of their research were published this week in the science journal Nature Communications.