Stem Cell Research

Stem cells are undifferentiated cells that have the ability to become any type of body tissue or specialized cell. Scientists believe that cures for many diseases could be found from research using stem cells. There are four basic kinds of human stem cells: embryonic stem cells (hES cells), which are obtained from 5-7 day old blastocysts; fetal stem cells, which are obtained from 4-6 week old fetuses that have been aborted either spontaneously or through procured abortions; placental/cord blood stem cells, which are obtained from the umbilical cord or placenta immediately after birth; and adult stem cells, which are obtained through a biopsy of mature tissues or from bone marrow of a post-natal human being (not necessarily the tissue or bone marrow of an adult). These stem cells can also be classified according to whether they are totipotent or pluripotent. Embryonic stem cells are virtually totipotent, meaning they can become any type of human cell, including at their earliest stage before any differentiation has occurred those cells that make-up the trophoblast (the outer-layer of the blastocyst, which eventually becomes the placenta). Fetal stem cells, placental/cord stem cells, and adult stem cells are all pluripotent, meaning they are not totipotent, but they can become some or many types of cells found in the human body. Currently it is thought that fetal stem cells are more pluripotent, i.e., they can become more types of cells, than placental/cord stem cells, while placental/cord stem cells are more pluripotent than adult stem cells. The current thinking in the scientific community is that embryonic stem cells may be more useful than adult stem cells in creating treatments and possible cures for diseases such as Parkinson's, Alzheimer's and spinal cord injuries. From a scientific perspective, however, the downside of totipotent embryonic stem cells is that they are more difficult to control and manipulate in the lab than pluripotent stem cells. Some researchers are exploring ways to increase the pluripotency of non-embryonic stem cells. Some studies are beginning to support the theory that adult stem cells are much more pluripotent than originally thought, and are able to turn into many more types of cells and tissues than previously suspected. [See, Martin Körbling, Ruth L. Katz, Abha Khanna, et. al. Hepatocytes and Epithelial Cells of Donor Origin in Recipients of Peripheral-Blood Stem Cells. New England Journal of Medicine 346, 10 (2002): 738-746.] At present, there is much speculation regarding how long it will take to develop useful therapies using any type of stem cell. Estimates range from 5-10 years up to 15-20 years.

While there is much debate within the medical and scientific communities as to which type of stem cells will be most useful for developing actual therapies, there is also much moral debate as to whether or not some types of stem cell research should actually be conducted in the first place. For example, in order to obtain hES cells, scientists must destroy or remove the trophoblast of the blastocyst, which results in the death of the embryo. Research on fetal stem cells may also be morally problematic if they are obtained through procured abortions (as opposed to spontaneous abortions, i.e., miscarriages). These types of research create a dilemma for anyone who believes that human life at all stages of its development is deserving of great respect, as the Catholic Church teaches. While it acknowledges that there are potentially great benefits that might result from hES cell research, the Catholic Church teaches that the destruction of innocent human life is intrinsically immoral, i.e., the destruction of innocent human life is unjustified no matter how good the intention or consequence of that action may be. However, those in favor of hES cell research argue that, because the majority of embryos from which stem cells are obtained are "excess embryos" in fertility clinics that are scheduled to be destroyed, we should at least obtain some good from them first by harvesting their stem cells for research. This debate concerning the moral status of hES cell research has received significant attention in the public arena.

The first scientific developments using human embryonic stem cells occurred in 1998 when researchers at the University of Wisconsin and John Hopkins University simultaneously isolated and grew the first hES cell lines in the lab (see, James Thomson, et. al., "Embryonic Stem Cell Lines Derived from Human Blastocysts," Science 282 (5391): 1145-47, 1998). This development prompted the NIH to consider whether or not research on hES cells violated the Reagan Era ban on federal funding of research that involved harm to or the destruction of human embryos. In 1999, the NIH published guidelines allowing the federal funding of research on hES cells, but not federal funding for the destruction of the embryos from which the stem cells are derived (see http://stemcells.nih.gov/index.asp). President Clinton then approved and adopted these guidelines in Sept. of 2000. However, no funds were actually dispensed by the NIH to research projects involving hES cells before president George W. Bush took office in early 2001. In the summer of 2001, President Bush reconsidered the validity of the NIH guidelines. In August of 2001, he decided that while funding could be provided for research on hES cells, this funding had to be limited to research on those embryonic stem cell lines that already exist so as not to encourage further embryo destruction. President Bush's decision also specified that 250 million federal dollars would go to fund adult stem cell research.

Reaction to President Bush's decision was mixed. Medical researchers and the biotech industry found the Bush statement difficult to swallow, because it means only a small fraction of the funding for embryonic stem cell research that would have been available under the pre-existing NIH guidelines will now be available. Furthermore, there is concern within the medical and scientific community that the existing lines for which federal funding may be provided will have only limited research potential. The nation's Roman Catholic bishops supported the move away from the Clinton policy, but generally thought that Bush's decision did not go far enough in protecting innocent human life. (For various reactions by the bishops, see Origins: CNS Documentary Service, August 30, 2001, Vol. 31: NO. 12, pp. 205-215). Regardless, the President's decision does appear to open the door for increased research with stem cells, both embryonic and adult. Some individual's predict that once the ability to manipulate stem cells has been achieved, therapies utilizing stem cells will become pervasive throughout the continuum of care and revolutionize the way health care is delivered.

[Further Sources: George Annas, et. Al., "Stem Cell Politics, Ethics, & Medical Progress," Nature Medicine 5: 1339-1341. Lisa Sowle-Cahill, "Stem Cells: A Bioethical Balancing Act," America March 26, 2001. Richard Doerflinger, "Destructive Stem Cell Research on Human Embryos," Origins 28: 771-773, 1999. Richard Doerflinger, "The Ethics of Funding Embryonic Stem Cell Research: A Catholic Viewpoint," Kennedy Institute of Ethics Journal 9: 137-150, 1999. John A. Robertson, "Ethics & Policy in Embryonic Stem Cell Research," Kennedy Institute of Ethics Journal 9: 109-136, 1999. National Institute of Health, Stem Cells: Scientific Progress and Future Research Directions: Opportunities and Challenges: A Focus on Future Stem Cell Applications, http://stemcells.nih.gov/stemcell/scireport.asp.]

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