Unlike any specific adult cell, embryonic stem cells are undifferentiated cells that have the ability to form any adult cell, and can proliferate indefinitely in culture (Embryonic pp). Using fourteen blastocysts obtained from donated, surplus embryos produced by in vitro fertilization, James Thomson and a group of University of Wisconsin biologists established five independent stem cell lines in November 1998, the first time human embryonic stem cells had been successfully isolated and cultured (Embryonic pp). The embryos used in the work were originally produced to treat infertility and were specifically donated to the project with the informed consent of donor couples (Embryonic pp).

Embryonic stem cells are of greatest interest due to their ability to develop into virtually any other cell produced by the human body, thus in theory, "if stem cells can be grown and their development directed in culture, it would be possible to grow cells of medical importance such as bone marrow, neural tissue or muscle (Embryonic pp).

It is likely that the first potential applications of human embryonic stem cell technology will be in the area of drug discovery because the ability to grow pure populations of specific cell types offers a "proving ground" for chemical compounds that could have medical importance (Embryonic pp). This ability to treat certain cell types with chemicals and measure their response offers a short-cut to sorting out chemicals that can be used to treat certain diseases that involve those specific cell types (Embryonic pp). In other words, stem cell technology would allow for the rapid screening of hundreds of thousands of chemicals that today are tested through much more time-consuming processes (Embryonic pp).

Because the earliest stages of human development are difficult or impossible to study, human embryonic stem cells offer insights into developmental events that cannot be studied directly in humans in utero or fully understood through animal models (Embryonic pp). Knowledge of the events that occur during the first stages of development has potential clinical significance for preventing or treating birth defects, infertility...

Moreover, knowledge of normal development could allow the prevention or treatment of abnormal human development, such as screening drugs by testing them on cultured human embryonic stem cells might help reduce the risk of drug-related birth defects (Embryonic pp).
This ability to grow all types of human tissue opens the door to treating a range of cell-based diseases and to growing medically important tissues that can be used for transplantation purposes (Embryonic pp). Diseases such as juvenile onset diabetes mellitus and Parkinson's disease, for example, occur due to defects in one of just a few cells types, and the ability to replace faulty cells with healthy ones offers hope of lifelong treatment (Embryonic pp). The same holds trues for failing hearts and other organs, which in theory, could be shored up by injecting healthy cells to replace damaged or diseased cells (Embryonic pp).

In Portugal, Dr. Carlos Lima is experimenting in stem cell treatment by taking adult stem cells from inside a patient's nasal passages, which are the only nerve cells in the body that regenerate, and transplanting them onto damaged nerve cells in the spine, where they will continue to grow (Schieffer pp).

In April 1005, a government advisory group proposed national ethical guidelines for human embryonic stem cell research and recommended research institutions establish oversight committees to enforce them (Group pp). Although President Bush has banned federal funding for stem cell research except for existing cell lines, private funding is continuing some new research (Group pp).

Works Cited

Group Calls for Stem Cell Research Rules.

AP Online; 4/26/2005

Schieffer, Bob; Kaledin, Elizabeth. "Stem Cells May Create Miracles."

CBS Evening News; 5/10/2005

Embryonic Stem Cells. University of Wisconsin-Madison. http://www.news.wisc.edu/packages/stemcells/facts.html#4

Genetic Engineering. http://en.wikipedia.org/wiki/Genetic_engineering

Stem Cell Basics. Stem Cell Information. National Institutes of Health. http://stemcells.nih.gov/info/basics