Magic Seeds

Biology 103
2002 Second Paper
On Serendip

Magic Seeds

Erin Myers

INTRODUCTION

Just before its end, the Clinton Administration implemented rules for federally funded human stem cell research allowing embryonic cell research of otherwise discarded sources. Upon inauguration, the Bush Administration immediately put a hold on federally funded human stem cell research until a compromise was reached in August 2001. The controversy over human stem cell research springs the origin of embryonic stem cells.

Within one day after fertilization an embryo, which until this point is simply a fertilized egg, begins to cleave, or divide from one cell to two, from two cells to four, etc. When the embryo reaches 34-64 cells it is considered a blastocyst. It is four or five day old embryos, blastocysts of about 150 cells, which are implanted into a uterus during in vitro inplantation.4 Many embryos are made and kept frozen as back ups in case implantation is unsuccessful. When a family decides they no longer need the embryos they can opt to dispose of them, put them up for adoption, or donated them for research.

Embryonic stem cells come from blastocysts made in a laboratory for in vitro fertilization that are donated for research with the informed consent of the donor. Blastocysts have three components: the trophectoderm, an outer layer of cells that form a sphere; the blastocoel, a fluid filled cavity; and the inner cell mass, a cluster of cells on the interior that may ultimately grow into a fetus.1 It is from the inner cell mass that stem cells are harvested. The inner cell mass is extracted from the blastocyst and cultured on a Petri dish. Here the controversy arises. The embryo is no longer viable without the inner cell mass. For those who consider a blastocyst to be a living human being, this extraction is tantamount to the death of a human. This issue has given rise to a new platform for the anti-abortion vehicle.

The controversy and its resulting restrictions are hindering the exploration of what may be the future of medicine. There is evidence to suspect that stem cells may be used to treat -- even cure -- AIDS, Parkinson's disease, Multiple Sclerosis, heart disease, cancers, diabetes, Alzheimer's, genetic diseases, and a host of other diseases.

MAGIC SEEDS

All stem cells have three promising characteristics: they are capable of proliferation, they are unspecialized, and can be differentiated. Proliferation is the ability of certain cells to replicate themselves repeatedly, indefinitely in some cases. Within six months, thirty stem cells can divide into millions cells.1 Stem cells are unspecialized; they are not committed to becoming a certain type of cell. They can be differentiated under certain protocols, tissue recipes scientists have identified,1 to become any of the 220 kinds of cells in the human body. Herein lay the great possibilities. Scientists may be able to produce cells that can replace damaged or sick cells in a patient with an injury or degenerative disease.6

A large portion of the political debate is devoted to alternatives to embryonic stem cells. Somatic stem cells, also referred to as "adult stem cells," are morally acceptable to the embryonic stem cell research opposition. Somatic stem cells come from select sources in fetal or human bodies. They exist in very small quantities in the umbilical cord of a fetus, bone marrow, the brain, peripheral blood, blood vessels, skeletal muscle, skin, and the liver. The number of somatic stem cells decreases with maturity. They exist to help repair their source, should injury occur. The majority of somatic stem cells are less transdifferentiable than embryonic stem cells. For the most part, they can only be coaxed into cells that are associated with their source. For instance, hematopoietic stem cells, harvested from blood vessels and peripheral blood, give rise to all the types of blood cells; and bone marrow stromal cells give rise to bone cells, cartilage cells, fat cells, and other kinds of connective tissue cells.1 Another disadvantage of somatic stem cell research is the difficulty to produce large quantities of somatic stem cells. Scientists also fear that somatic stem cells may lose their potency over time.12

A new study identifies a somatic stem cell that can "differentiate into pretty much everything that an embryonic stem cell can differentiate into." Catherine Verfaillie of the University of Minnesota found these cells in the bone marrow of adults and dubbed them multipotent adult progenitor cells (MAPCs). The study claims that MAPCs have the same potential as embryonic stem cells. These cells seem to grow indefinitely in a culture, as do embryonic stem cells. Encouragingly, unlike embryonic stem cells, MAPCs do not seem to form cancerous masses if you inject them into adults. Skeptics think the scientists stem cell selection process creates MAPCs and do not think these cells that exists on their own, they think the scientist have simply found a way to produce cells that can behave this way.8

Stem cell therapy testing in rodents is yielding exciting results. Mouse adult stem cells injected into the muscle of a damaged mouse heart have help regenerate the heart muscle. In another experiment, human adult bone marrow stem cells injected into the blood stream of a rat similarly induced new blood vessel formation in the damaged heart muscle and proliferation of existing cells. Petri dish experiments also have promising applications. Parkinson's disease, a neurodegenerative disorder that affects more than 2% of the population over 65 years of age, is caused by a progressive degeneration and loss of dopamine-producing neurons. Scientists in several laboratories have been successful in inducing embryonic stem cells to differentiate into cells with many of the functions of the dopamine neurons needed to relieve the symptoms of Parkinson's disease.1

There are many more implications for stem cell research. In addition to cell therapy, human stem cells may also be used to test drugs. Animal cancer cell lines are already used to screen potential anti-tumor drugs.1 The possibilities are endless.

CONCLUSION

There are over 200,000 embryos left over from in vitro fertilization3 attempts but only about 6 existing embryo stem cell lines2 available for federally funded research under Bush Administration regulations. United State's scientists pioneered this field of research. Federal funding could speed the development of therapies and keep the United States at the forefront of science.2 Alta Charo, a law and medical ethics professor at the University of Wisconsin and member of the National Bioethics Advisory Committee, is against any potential limitations placed on the numbers of cells available.11 Great numbers of blastocysts are needed to harvest a diverse selection of stem cells. Diversity is needed to expand the range and reliability of research and for immunological "matching reasons."9 While opposition is mainly coming from the conservative side of the political spectrum with anti-abortion sentiments, some people, including Senators Orrin Hatch and Tent Lott, who are unremittingly anti-abortion are pro stem cell research.9

The anti-abortion opposition believes that life begins at fertilization and that life should not be compromised even if it is to save the lives of many. The conservative Family Research Council goes so far as to say that every frozen embryo deserves "an opportunity to be born."12 About 15% of pregnancies end in miscarriage, most of them in the embryo stage before the woman even knows she is pregnant.7 If every frozen embryo was given the opportunity to be born, and the 85% that statistically survive to become fetuses were born, there would be 170,000 more babies in the world. This is dramatically more than 15 times the number of babies born in the United States each day.

The potential for stem cell therapy is too great to deny federal funding to new embryonic stem cell research. The current strict regulation slows progress and inhibits vital research, restricting federally funded research to six embryonic stem cell sources. There should be supervision to ensure research does not lead to utilitarian purposes, but the number of embryos used should not be limited. Scientists would not need to harvest stem cells indefinitely. At some point, they would have a wide enough variety and would be able to stop.9 Extracting "magic seeds" from a cluster of cells could end disease, but we will never know if we are not allowed to try.

WWW Sources

2) Research avenue adds fuel to stem cell controversy 

3) Adoption of Frozen Embryos

4) Click on "Flash: Embryonic stem cell explainer

5) Cancer, AIDS hope from stem cell study

6) The Great Debate Over Stem Cell Research

7) If You Believe Embryos Are Humans...then curbing stem cell research is an odd place to start protecting them

8) Ultimate stem cell discovered

9) Elizabeth Cohen: Ethics of stem cell research

10) Bush's Stem Cell Decision Displeases Scientists

11) Awaiting Bush's Stem Cell Choice

12) Click on "Common Questions" Andrew Goldstein explains the key issues

For more information visit

Great illustration of stem cell harvesting

Stem Cell Research News.Com