Stem Cells, or “A Rose, By Any Other Name…”

Over the past several years the media has been full of stories about stem cells.

The topic of stem cells is one that everyone, from President Bush on down, has a strong opinion about.

But what are stem cells? Are there different types of stem cells? And what kinds of things are researchers hoping to learn about by doing “stem cell research”?

I’ll try to answer some of those questions here.

First of all, what is a stem cell?

To answer that, I’ll start with one of the main principles of modern biology: in every organ in your body, there are cells that are fully developed (differentiated is the term scientists use), and cells that sit in reserve to replace the differentiated cells as they age. Those cells that sit in reserve are unique in their ability to both create copies of themselves (called self-renewal) and to create “daughter cells” that are more differentiated. These “daughter cells” are stem cells.

Stem cells come in two varieties: the ones that are found in mature organs (like bone marrow) and the ones that are found in a developing embryo and give rise to the entire body.

So what are the controversies that surround stem cells? Well, the major controversy is over the source of stem cells that scientists use for their experiments. For example, most people are not concerned about stem cells that are harvested from bone marrow, but they do object to embryonic stem cells that require the destruction of an embryo. I guess it’s obvious why some people find that objectionable but others do not.

What good are stem cells, anyway? What kinds of things do scientists think they can do with stem cells? I study stem cells. I know many other people who study stem cells. No one I know wants to do what the loudest anti-stem-cell-research voices are shouting about – clone a human. What we do want to do is exploit the potential of these cells to replace broken cells and cure human disease.

How might this happen? Well, let’s use spinal cord injury as an example. At the moment, there’s no way to reverse a serious spinal cord injury because the nerve cells that make up the spinal cord don’t regrow once they are damaged. But imagine if we could take stem cells and grow new nerve cells and we could put those cells into an injured spinal cord and fix it. We could reverse paralysis. That would be amazing.

Or… what if we could replace the cells in the pancreas that are destroyed in patients who have diabetes? If we could reliably turn stem cells into insulin-producing cells, diabetes would change from a disease that can be “managed” with multiple daily injections of insulin to a curable disorder. What a difference that would make!

What about cancer research? Why do I study stem cells? Well, many oncologists believe that tumors, like normal organs, are composed of differentiated cells and stem cells. It is the stem cells that are resistant to chemotherapy and radiation therapy. It is the stem cells that are responsible for relapse. It is the chemotherapy-resistant stem cells that spread throughout the body and ultimately kill patients. So, unlike my colleagues who want to harness stem cells for good, I want to learn what makes them tick, learn their vulnerabilities, and exploit those vulnerabilities to develop treatments that will cure patients without making them as sick as our current chemotherapies do.

Several states, including California and my own home state of Maryland, have recognized the enormous importance of stem cell research and have designated significant sums to support stem cell research. In contrast, the federal government placed significant restrictions on stem cell research back in 2001. Hopefully soon they will realize the mistake they made, listen to Nancy Reagan, and give this vital area of research the support it deserves.