Stem Cell Breakthrough

In late November Dr. Shimya Yamanaka reported in Cell that he had produced human stem cells from adult human cells taken from the cheek of a middle-aged woman. On the same day, Dr. James Thomson reported in the online version of Science that he had achieved similar success with foreskin cells from newborns.

Scientists are hailing these two reports as a technical breakthrough in stem cell research. The key is that these two researchers derived their stem cells from older cells, NOT from embryonic cells. Stem cell research has always been highly controversial because most of the stem cells used in research come from human embryos (see the Current Issue in Human Biology 5th ed., pp. 72-73). But if human stem cells can be created from older cells without sacrificing human embryos, then the whole “sanctity-of-life” issue is off the table. An added benefit is that if a simple cheek cell can be used, then stem cells could be grown specifically for any patient, using cells taken from that patient.

It’s way too early to think of growing a new heart for a patient in heart failure from his/her own cells, though. Although these new findings show that we have reached a basic level of understanding of how to create stem cells, we don’t yet understand how to direct them into becoming the specific human organs or tissues we might need to treat disease. Many scientists, including Dr. Yamanaka and his colleagues, argue that it would be “a serious mistake” to move too quickly to end all embryonic stem cell research, based on these very first successes at creating stem cells from adult cells. They believe that embryonic stem cells are still likely to be necessary for decades to come.

Still, it’s encouraging to think that in our lifetimes, the controversy over stem cell research may just slowly disappear.