What is meant by stem cell research?

Human Quest, Jan/Feb 2002 by Swomley, John M

Stem cell research and therapies have come under attack, so it is important to know that such research does not involve zygotes, embryos or fetuses in the womb. It has involved animals, fetal tissue from terminated pregnancies, and embryos from in vitro fertilization clinics when embryos are in excess of the number used in the implantation process. In each case, informed consent must be given from the human donor.

Stem cells are cells that have the ability to divide for indefinite periods in culture and to develop into specialized cells. For example, when a sperm fertilizes an egg and creates a single cell, that cell has the potential to form an entire organism. In the first hours after fertilization, this cell divides into identical cells that are equal in their potential.

If either of these cells is placed into a woman's uterus it has the potential to develop into a fetus. About four days after fertilization and

after several cycles of cell division, these cells begin to specialize, forming a hollow sphere of cells called a blastocyst. The blastocyst has an outer layer of cells and inside the hollow sphere is a cluster of cells called the inner cell mass.

The outer layer of cells will form the placenta and supporting tissues needed for fetal development. The inner cell mass can form virtually all the tissues in the body, but cannot form the placenta and related tissues necessary for fetal development. If an inner cell mass alone were placed in the uterus it would not develop into a fetus.

A "stem cell line" is established when the cells become a self-replenishing colony, creating generation after generation of identical cells. Embryonic stem cells are the basic building blocks for the 260 or so cell types in the body. During development, stem cells transform into heart, muscle, brain, skin or other tissues.

Cloning is the making of embryos for reproduction Therapeutic cloning would create embryos whose cells might be useful to provide tissues which would provide treatments for patients who need an exact tissue match.

One problem for legislation now banning all cloning or banning other procedures is that it interferes with as-yet-unknown or incomplete research. Embryonic cell research differs from cloning; instead of beings inserted into a womb to become a fetus, the fertilized ovum would be kept in lab dishes and used to generate stem cells.

Still another problem is religious suspicion of science. Some people believe that a soul enters a body at an, unknown stage and that therefore scientific and hence medical research; should be forbidden or restricted.

Adult stem cells are available, but are not so prolific or versatile as embryonic stem cells and have not proven to possess the same range of capabilities. Also, adult stem cells seem to be tissue-specific. For example, blood stem cells make only new blood cells.

Much more research is needed, both for embryonic and adult cell possibilities, as such research is only in its initial stages.

John M. Swomley is Emeritus Professor of Social Ethics, St. Paul School of Theology, Kansas City, MO and chairperson of The Churchman Co.