It’s a possible alternative to using embryos for stem cells
By MARK JOHNSON MCCLATCHY NEWSPAPERS
MILWAUKEE ? In work that extends science?s power to alter the basic unit of a human being, researchers at the University of Wisconsin-Madison have taken skin cells that were reprogrammed back to their embryonic origin and grown them into functional, pulsing heart cells.
Moreover, the human heart cells grown using this technique were very similar to those grown from embryonic stem cells, the scientists reported Thursday in the journal Circulation Research.
Tim Kamp, cardiologist and associate professor within the School of Medicine and Public Health at the University of Wisconsin-Madison.
Timothy Kamp, co-director of UW?s Stem Cell & Regenerative Medicine Center and one of the authors of the new paper, said the reprogrammed heart cells made in the laboratory performed some key functions of the heart cells inside our bodies. They generated electrical pulses, and in response to these pulses, they contracted. It is the collective contraction of all these cells that enables the heart to beat.
?This is a proof-of-principle experiment, but it?s not ready for prime time,? Kamp said, cautioning that such manufactured heart cells are not yet safe for human use.
The cells, called cardiomyocytes, had once been skin cells. To turn cells from skin to heart, scientists first sent them back to the embryonic state by infecting them with viruses carrying genes, a method that could cause cancer.
Still, the reprogrammed cardiomyocytes offer researchers an immediate tool for studying heart diseases in a lab dish and testing drugs against them.
The new paper adds to a growing body of evidence suggesting that scientists can now obtain cells that perform just like embryonic stem cells without destroying a human embryo. Since teams led by James Thomson at UW and Shinya Yamanaka at Kyoto University showed in 2007 that human skin cells could be returned to the embryonic state, researchers have sought to determine whether the new technique can be used to make all of the more than 200 cell types in the body.
This versatility is one of the crucial powers of an embryonic stem cell, offering modern medicine a potential repair kit for illnesses such as Alzheimer?s, diabetes and heart disease. In the last year, scientists have used reprogramming to make blood cells and motor neurons, the cells that transmit nerve impulses and make muscles contract
