Interview With Father Thomas Berg of Westchester Institute

NEW YORK, JUNE 14, 2005 (Zenit) - There might be an ethically acceptable alternative for obtaining embryonic stem cells, says a bioethicist.

Legionary of Christ Father Thomas Berg, executive director of the Westchester Institute, a Catholic ethics think tank located in suburban New York, sees hope for a process known as altered nuclear transfer. He gave an overview of the status of stem cell research in this interview with us.

Q: What is the ethical problem with embryonic stem cell research?

Father Berg: The problem is that the methods currently used to obtain these cells -- pluripotent stem cells -- require researchers to kill living human embryos in the process.

In the case of so-called therapeutic cloning, which has been accomplished twice and recently streamlined by a group of South Korean researchers, it requires the intentional creation of human embryos precisely for their destruction in the course of harvesting stem cells from them.

Q: Are not human adult stem cells sufficient for all the therapeutic purposes we could want?

Father Berg: We really can't say enough in praising and promoting the inroads that have been made in developing therapies from adult stem cells.

Decades of research have yielded some 70 diverse therapies and clinical applications in treating diseases and disorders, including heart damage, spinal injury and several kinds of blood diseases.

By contrast, the research on deriving therapies from human embryonic stem cells is more nascent; it has only been going on in earnest for the last four or five years. Will it yield therapies? Quite possibly -- that's what scientists on both sides of the life issue tell me. It's too early to tell.

So, we should be guarded in our optimism with regard to the potential of adult stem cells.

Q: Can you explain again the difference between kinds of stem cells?

Father Berg: In the case of embryos, we distinguish between pluripotent and totipotent.

Pluripotent cells can give you -- to use an analogy with painting -- all the colors on the palette, but not the whole picture. That is to say, they give you all the human tissues.

Totipotent cells, on the other hand, can give you the whole picture -- a whole human being. It's the pluripotent cells that are of interest to the researchers.

Human adult stem cells are normally referred to as multipotent. There is ongoing debate as to whether certain kinds of adult stem cells -- for example, MAP-Cs, or multipotent adult progenitor cells -- can be coaxed to give rise to all tissue types. There are some reports that scientists are perhaps on the right trail, but no conclusive studies yet.

Q: How does cloning relate to stem cell research?

Father Berg: Cloning is the creation of a unique human individual through a process called somatic cell nuclear transfer.

A donor donates a body cell from which the nucleus is taken and then transferred into an enucleated human egg. Factors in the cytoplasm of the egg are responsible for literally reprogramming the inserted nucleus to a pristine state, that of a one-cell human organism or zygote.

When coaxed with electrical stimulation, this clone begins to undergo the normal process of cell division which leads to the various stages of otherwise normal embryonic development. So the link with stem cell research is the following.

Cloning has been proposed as the ideal means of creating tailor-made embryonic stem cell lines. The DNA of the clone is an exact match of the donor's. The clone is developed to the blastocyst stage, about 6 days, at which point, its inner cell mass is extracted -- killing the human clone in the process.

From the inner cell mass of the clone are then derived in culture a new line of pluripotent stem cells which are a perfect genetic match to the donor. These lines of stem cells could be used to develop tissue replacement therapies for the donor -- should he or she eventually need them -- with no risk of immune rejection because the tissue is perfectly matched.

Q: Has anyone yet cloned a human being?

Father Berg: Yes. The South Korean team led by Woo Suk Hwang reported, in February 2004, the first successful creation of cloned human beings.

In 2004 they created some 30 embryos and allowed them to develop to the blastocyst stage. They were then destroyed in order to create lines of embryonic stem cells. On May 19 of this year, they reported that they have now honed their technique and claim to have created 11 new lines of human embryonic stem cells.

Q: Do you defend the Bush policy on funding of embryonic stem cell research?

Father Berg: While I am open to ...