Is embryonic stem cell research necessary?

If--according to the last entry I posted--adult stem cells can treat 65 different diseases/conditions and embryonic stem cells 0, why is research being conducted with embryonic stem cells and why is there a debate about federal funding of same? A number of possible reasons have been proposed:

  • Media hype, hope, and promises
  • Terminology is confusing, so few know what is going on
  • The limitations of adult stem cells
  • The National Academies of Science (and NIH) said so

Media hype, hope, and promises

The first embryonic stem cell was created in 1998. Seven years is plenty of time for media hype, but not enough to cure the many diseases/conditions promised daily in newspapers and television. Over the Labor Day weekend, Robert Winston, a leading fertility expert in the UK where embryonic stem cell research is legal and funded stated that he believes that the benefits of stem cells have been overhyped. His announcement has received almost as many Google alerts as Senator Frist's change of mind, indicating that sensational news whether good or bad tends to get transmitted around the world very quickly.

Testimony by famous people such as Christopher Reeves and Nancy Reagan help keep the widest possible options active.

Terminology is confusing, so few know what is going on

Perhaps embryonic stem cell research is still in the news because people are so confused about the language used that the most controversial keeps hogging the spotlight. The phrase stem cell alerts readers to interesting and perhaps controversial news, as does the word cloning. Even embryonic is not specific enough. Reiterating some of the confusion may show how complex the terminology problem is.

An adult cell is one that has fully differentiated into its functional state in the body for example, the rods and cones of the eye are adult cells even if they are found in a child or a fetus. An adult stem cell is, presumably, a cell in a cell in a human body that produce a copy of itself under some conditions and a more differentiated cell in other conditions these are the hematopoietic (blood-forming) and mesenchymal (connective-tissue forming) cells of the bone marrow and other clusters of cells elsewhere in the body.

Stem cells taken from the umbilical cord of a newborn human infant or from the fluid around a developing fetus or from other amniotic tissues (including a portion of the placenta) are also called adult stem cells. These are sometimes called stem cells with embryonic potential or embryonic-like stem cells, since they are believed to be capable of developing into more tissue types than adult stem cells from a particular adult tissue.

Generally, the name embryonic stem cell is reserved for cells derived from the inner cell mass of the blastocyst stage of early embryonic development. By the way, the outer layer of the blastocyst is necessary for implantation and for development of the placenta and umbilical cord.

A stem cell derived by transfer of adult DNA into an unfertilized egg (the Korean stem cell lines) or into an embryonic stem cell (the Harvard stem cell) is also an embryonic stem cell even though it may not have been taken from an embryo and certainly could not have developed into a human being.

The earlier blog entry, Interpreting stem cell research, provides a clear way to analyze reports in the media and--perhaps--to deal with confusing terminology

The limitations of adult stem cells

Some argue about it, but there is strong support of the conclusion that adult stem cells are not as versatile as embryonic stem cells. One limitation is that most of the diseases/conditions treated with adult stem cells (bone marrow source) are related to rescuing the body's ability to make blood cells and fight infections. Many of those who argue against embryonic stem cell research include umbilical cord blood cells in the category of adult stem cells. We are learning, as expected, that the manipulation of stem cells into tissues in the laboratory differs from the same differentiation in the body and that the milieu in which the cells live matters greatly. Perhaps adult stem cells are not as limited as they seem and we only need to figure out what's needed to make them more versatile.

At the same time, adult stem cell transplants have been around for 40 years and have yet to cure Parkinsons, Alzheimers, muscular dystrophy, spinal cord paralysis.

The National Academies of Science (and NIH) said so

In 2002 the National Academies report Stem Cells and the Future of Regenerative Medicine called for human stem cell and human embryonic stem cell research to move forward. The report argued for federal funding of research deriving and using embryonic stem cells from a variety of sources, including those from nuclear transfer. The reasons for federal funding were that progress in the field is less likely to be hindered and there's greater opportunity for regulatory oversight and scrutiny of the research. Bush's later Presidential Directive limited the stem cell lines to those in existence in August, 2001. The National Research Council and the Institute of Medicine recently released their Guidelines for Human Embryonic Stem Cell Research, which are intended to provide some consistency in how embryonic stem cell research is conducted.

Marie Godfrey, PhD
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