Ordinary Skin Cells are Reprogrammed to Beat as Heart Cells

Circulation Research, February 12, 2009

Their rhythmic beating clearly visible, just in time for Valentine's Day, the iPS (induced pluripotent stem) cells exhibit all the characteristics of cardiac cells, even from within their laboratory dish. These cardiac cells were not differentiated from embryonic stem cells, however, nor from any type of stem cell, but instead they were obtained by the reprogramming of ordinary, fully mature and differentiated adult skin cells. Since cardiac cells are among the most specialized of all cell types within the human body, such a dramatic demonstration is visible proof, at least in principle, of the ability of iPS cells to differentiate into virtually any type of bodily tissue.

According to Dr. Tim Kamp, a cell biologist who holds titles of associate professor in both medicine and physiology at the University of Wisconsin at Madison, and who led the study, "This is the first demonstration that human induced cells can form different types of heart cells in a dish. We didn't know whether they could form heart cells efficiently. But they successfully formed heart cells with all the electrical and organizational properties we'd expect."

Contrary to popular misconception, however, iPS cells won't be available any time soon at your local neighborhood doctor's office. The genetic reprogramming that is involved in reverting an ordinary mature skin cell into a more primitive cell, that merely resembles a stem cell, is still too dangerous to be used as a clinical therapy in real people. Among other problems, there is still a high risk of tumor formation from the genetic mutations that are required for reprogramming of the cells, not to mention also biological contamination and other unresolved difficulties, so scientists still have a long road ahead of them before such "technicalities" can be overcome.

Nevertheless, this demonstration adds yet one more example to the growing list of cell types that have been obtained without the use of embryonic stem cells, and which therefore circumvent at least the contentious ethical controversies, if not also the unsolved scientific problems and medical risks, associated with embryonic stem cells.