"Customized" Primordial Stem Cells

Few researchers seeking to generate primordial stem cells are yet pairing this research with the Dolly-type somatic cell nuclear transfer. Both primordial stem cell research and somatic cell nuclear transfer are new. Each type of research must proceed before we can see how they relate to each other and might be combined. But there is the possibility of pairing them to produce a "customized" stem cell based on the DNA of the patient.

Few suspected prior to the experiment which led to the birth of "Dolly," the sheep, that adult somatic cells could be reprogrammed to an undifferentiated, totipotent status. We do not know what is possible with primordial stem cells. It is not yet possible to say how important it will be to combine primordial stem cell research with somatic cell nuclear transfer, but it would be unwise in the extreme to preclude the possibility.

The current research priority is to develop primordial stem cells which are "universal donors," that is cells which could be transplanted into any individual with a minimum of immune rejection response. I believe that this might be possible.

It might prove desirable in some or many cases, however, to develop primordial stem cells which are "customized" to an individual. A researcher or doctor might want to generate a primordial stem cells which contains DNA identical to that of the patient who needs the therapy. By starting with the DNA from the patient, the primordial stem cell therapy would be compatible with, and not be rejected by, the person for whom the therapy is created. By starting with the patient’s own nuclear DNA, the therapy is, in effect, custom made for that person. If you will, the therapy has the patient’s monogram on it. Taking this DNA as the starting point the researchers or doctors would have to use the "Dolly" technology to reprogram somatic cell nuclei and to generate more undifferentiated primordial stem cells for that patient. This may include the use of the cytoplasm of an unfertilized oocyte, or only specific molecules of the cytoplasm that are capable of de-differentiating a somatic cell.

This process of using the patient’s own cells is similar to current technologies that utilize a patient’s own bone marrow, cleansing it of cancer, irradiating all the remaining bone marrow in the patient (bringing them to the verge of lethality), and then giving them a bone marrow transplant of their own bone marrow. This is obviously a very complex and harrowing process and it is taken to avoid the immune system rejection of bone marrow from another source. Others are fortunate to have siblings who have compatible bone marrow and a very few are lucky enough to have a twin.

Stem cells might be "customized" for a group, not just one individual, but they might start with the DNA of one individual who is representative of that group. That person would be one who exemplifies a genetic or immune system profile with other individuals in a group.

We might want to pursue "customized" stem cells if we find that there are some limitations on the use of a "universal donor" primordial stem cell. It may be the case that the "Dolly" technology will be perfected sooner and that we might be able to develop a "customized" primordial stem cell before we can develop a "universal donor" primordial stem cell. We might find it beneficial to pursue both approaches. Some companies might pursue one strategy and other companies might pursue another one and patients will be the beneficiaries of the competition and creativity.