A new stem cell institute being set up at Stanford University will study a wide variety of human diseases through two advanced but controversial techniques of cell manipulation. One is nuclear transfer, also used in cloning animals, and the other will involve generating new lines of human embryonic stem cells.
The institute will be headed by Dr. Irving Weissman, a Stanford expert on the stem cells in the bone marrow that daily renew the red and white blood cells. An anonymous donor has provided $12 million to start the institute.
Dr. Weissman said he intended to explore two promising new lines of inquiry made possible by embryonic stem cells. The first is to find out if stem cells and cancer cells may use the same genetic machinery to replicate themselves. Stem cells multiply freely to generate all the mature cells of the body, and though mature cells lose this ability cancer cells somehow regain it.
A later goal will be to use stem cells to develop models of human disease, meaning cultures of cells that can be studied in the laboratory. Dr. Weissman gave as an example the creation of a model for Lou Gehrig's disease, which is caused by the mysterious death of the motor neurons that control the muscles. From a patient's body cell, the nucleus -- which contains all the DNA including the faulty genes that cause the disease -- would be extracted and inserted into an unfertilized human egg whose own nucleus had been removed. Still in a laboratory dish, the egg would develop after a few days into the early, pre-implantation embryo known as a blastocyst.
The blastocyst's inner cell mass, from which all the different cell types of the body are formed, would then be removed and the cells, now known as embryonic stem cells, would be exposed to signals that make them develop first into nerve cells and then into the specialized motor neurons. If these start to die, just as they do in patients with Lou Gehrig's disease, researchers should have an excellent opportunity to pinpoint the errant genes that are responsible and to devise drugs to counter their subversive action.Continue reading the main story
The same technique, Dr. Weissman said, could be used to create models of any other human disease, with the embryonic stem cells being converted into whatever type of tissue the disease affects, whether the pancreas in the case of diabetes or basal cell ganglia in the case of Parkinson's disease.
''This is so important that we finally have the chance to get a handle on every one of these human multigenic diseases -- it would be wrong not to try it,'' Dr. Weissman said. Multigenic diseases, which are caused by several errant genes acting in concert, are particularly hard to analyze because they follow no obvious pattern of inheritance.
A flurry of news reports yesterday portrayed the Stanford institute as planning to do a form of human cloning, and Dr. Weissman said he was distressed to see his research plan presented in that light. The nuclear transfer technique is used by animal cloners to make blastocysts that are then inserted into an animal's womb. In Dr. Weissman's proposal the blastocysts would stay in the Petri dish and be destroyed to make human embryonic stem cells.
The creation of human embryonic stem cells has been controversial because some critics, including the Roman Catholic Church, object to destroying human blastocysts, even the surplus ones created in fertility clinics. Under the compromise announced by President Bush on Aug. 9, 2001, researchers using federal money may work with stem cell lines established before that date but not generate new ones of their own. This restriction does not apply to biologists who do not use federal money for this part of their research.
Dr. Weissman noted that Gov. Gray Davis of California recently signed legislation outlawing the cloning of a person but encouraging nuclear transfer technology and other methods to make human embryonic stem cells.
He emphasized that the new institute's initial focus would be on cancer cells and exploring whether they proliferate because they have learned to switch back on the genes that were used by their stem cell predecessors. ''That opens up some wonderful possibilities because we would have a whole new set of genes to look at,'' Dr. Weissman said.Continue reading the main story