Stem Cell Primer

Stem cells are a hot topic among biotech businesses and on Capital Hill ? where the new Congress is again considering a bill to lift restrictions on federal funding for embryonic stem cell research.

But there?s still a lot of confusion among the public about what the cells are, what they can do and from where they come.


?I don?t think most people understand the science ? there?s an awful lot we don?t understand yet,? said Dale Carlson, spokesman for the California Institute for Regenerative Medicine, which was created to help administer $3 billion in stem cell funding for the state?s businesses and researchers.

While science still has a lot to learn about their workings, stem cells, simply put, are basically blank-slate cells that can renew themselves and also turn into other particular cells. They?re prized because they may be able to regrow tissue or even entire organs used to treat myriad diseases.


They?re also typically divided into two categories: embryonic and adult.

Human embryonic cells, first isolated in 1998, draw a lot of fire because of ethical concerns over creating and destroying embryos, though they?re thought to have the ability to become any type of cell in the body.

Most other stem cells are labeled ?adult,? though they come from a variety of sources ? including fetal tissue (some scientists are pushing for this as a third classification).

Generally, adult stem cells are thought to be more specialized in their development with fewer possibilities. But they?re also closer to producing commercialized therapies than other stem cell types. Baltimore?s Osiris Therapeutics, for example, has a drug made from bone marrow stem cells in late stage testing for two diseases.

Here?s a look at some of the various stem cells and what abilities they?re thought to have: