Growing Heart Cells Just for You

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http://www.technologyreview.com/biomedicine/38348/?mod=ExpMan_feature


Pieces of heart: Petri dishes hold cardiomyocytes grown from induced pluripotent stem cells that were created by reprogramming the author’s blood cells. The two middle dishes contain only water. Credit: Greg Ruffing

Peering through a microscope in Madison, Wisconsin, I watched my heart cells beat in a petri dish. Looking like glowing red shrimp without tails, they pulsated and moved very slowly toward one another. Left for several hours, I was told, these cardiomyocytes would coalesce into blobs trying to form a heart. Flanking me were scientists who had conducted experiments that they hoped would reveal whether my heart cells are healthy, whether they're unusually sensitive to drugs, and whether they get overly stressed when I'm bounding up a flight of stairs.

It was snowing outside the office-park windows of Cellular Dynamics International (CDI), where I was observing an intimate demonstration of how stem-cell technologies may one day combine with personal genomics and personal medicine. I was the first journalist to undergo experiments designed to see if the four-year-old process that creates induced pluripotent stem (iPS) cells can yield insight into the functioning and fate of a healthy individual's heart cells. Similar tests could be run on lab-grown brain and liver cells, or eventually on any of the more than 200 cell types found in humans. "This is the next step in personalized medicine: being able to test drugs and other factors on different cell types," said Chris Parker, CDI's chief commercial officer, looking over my shoulder.

CDI scientists created the little piece of my heart by taking cells from my blood and reprogramming them so that they reverted to a pluripotent state, which means they are able to grow into any cell type in the body. The science that makes this possible comes from the lab of CDI cofounder and stem-cell pioneer James ­Thomson of the University of Wisconsin, the leader of one of two teams that discovered the iPS-cell process in 2007. (The other effort was led by Shinya Yamanaka of Kyoto University.) The results are similar to the special cells that appear in embryos a few days after fertilization.

Since late 2008, the company has been manufacturing cardiomyocytes and mailing the frozen cells on dry ice to academic scientists to study how these cells work, and to researchers in the pharmaceutical industry to use in early tests of drug candidates. One important reason to use the cells is that they could reveal whether drugs are toxic to the heart, information that other types of testing can miss. "Several drugs have made it to the market that have cardiotoxic profiles, and that's unacceptable," Parker says. He says that the cardiomyocytes derived from iPS cells are a huge improvement over the cadaver cells sometimes used to test potential drug compounds. Unlike the cadaver cells, IPS-­generated cells beat realistically and can be supplied in large quantities on demand. What's more, iPS-generated cells can have the same genetic makeup as the patients they came from, which is a huge advantage in tailoring drugs and treatments to individuals. These made-to-order cells are not cheap, however. Cellular Dynamics' CEO, Robert Palay, says they cost about $1,500 for a standard vial of 1.5 million cells.