STEM CELL RESEARCH
Stem cell research is a complicated scientific and moral issue. It offers great promise for curing diseases and injuries, but also poses the threat of turning sacred human components into factory farm parts (remember the scene in the Matrix movie when Neo 'woke up'). In 1998 scientists discovered how to isolate stem cells from human embryos and grow the cells in the laboratory. Scientists have created human embryos in test tubes solely to experiment on them.
The embryos used in these studies were created for infertility purposes through in vitro fertilization procedures and when they were no longer needed for that purpose, they were donated for research with the informed consent of the donor. They are not derived from eggs fertilized in a woman's body. The embryos from which human embryonic stem cells are derived are typically four or five days old. In vitro fertilization is an assisted reproduction technique in which fertilization is accomplished outside the body.
The basic human fear behind stem cell research is misanthropy, which is a hatred or distrust of mankind. The basic question, just as in the case of nuclear research and other complex technologies, is whether man or womankind will do something evil with this knowledge.
All stem cells have three general properties:
- They are capable of dividing and renewing themselves for long periods;
- They are unspecialized; and
- They can give rise to specialized cell types with special functions such as the beating cells of the heart muscle or the insulin-producing cells of the pancreas.
Stem cells serving as a sort of repair system for the body, they can theoretically divide without limit to replenish other cells. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell such as a muscle cell, a red blood cell, or a brain cell. Research on stem cells is advancing knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. Cell-based therapies to treat disease, known as regenerative or reparative medicine, are treatment methods whereby stem cells are induced to differentiate into the specific cell types required to repair damaged or depleted adult cell populations or tissues.
|California voted 59% to 41% in the
2004 election to approve Proposition 71, the California
Stem Cell Research and Cures Initiative, to create a $3
billion fund to finance research on adult and embryonic
stem cells for 10 years. The proposition gives the state
the aurhority to borrow $3 billion to underwrite
experiments on embryonic stem cells. The $350 miillion
dollars per year in grants will be financed through state
bonds. The interest on the bonds, estimated to be about
$3 billion, will be paid back through tax revenues
The initiative was designed to by-pass the Bush administration, which enacted a policy in 2001 barring NIH grants for stem cell work involving the destruction of human embryos. The California effort will emphasize the type of research that the federal government does not fund -- new embryonic stem cell lines and embryonic stem cells derived through human cloning. Researchers can get their embryonic stem cells from leftover embryos at in vitro fertilization clinics, or from using the human cloning process.
Scientists primarily work with two kinds of stem cells from animals and humans, which have different functions and characteristics:
If scientists can reliably direct the differentiation of embryonic stem cells into specific cell types, they may be able to use the resulting, differentiated cells to treat certain diseases at some point in the future. In order to develop treatments for diseases sush as Parkinson's disease, diabetes, and heart disease, scientists are intensively studying the fundamental properties of stem cells, which include:
Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, stem cells give rise to the multiple specialized cell types that make up the heart, lung, skin, and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.
Scientists are trying to understand two fundamental properties of stem cells that relate to their long-term self renewal:
Discovering the answers to these questions may make it possible to understand how cell proliferation is regulated during normal embryonic development or during the abnormal cell division that leads to cancer.
Stem cells can give rise to specialized cells. When unspecialized stem cells give rise to specialized cells, the process is called differentiation. Scientists are just beginning to understand the signals inside and outside cells that trigger stem cell differentiation. The internal signals are controlled by a cell's genes, which are interspersed across long strands of DNA, and carry coded instructions for all the structures and functions of a cell. The external signals for cell differentiation include chemicals secreted by other cells, physical contact with neighboring cells, and certain molecules in the microenvironment
Growing cells in the laboratory is known as cell culture involves isolating human embryonic stem cells by transferring the inner cell mass into a plastic laboratory culture dish that contains a nutrient broth known as culture medium. The cells divide and spread over the surface of the dish. The inner surface of the culture dish is typically coated with embryonic skin cells that have been treated so they will not divide. This coating layer of cells is called a feeder layer. The reason for having the treated cells in the bottom of the culture dish is to give the inner cell mass cells a sticky surface to which they can attach. Also, the feeder cells release nutrients into the culture medium.
Adult and embryonic stem cells differ in the number and type of differentiated cells types they can become. Embryonic stem cells can become all cell types of the body. Adult stem cells are generally limited to differentiating into different cell types of their tissue of origin. Large numbers of embryonic stem cells can be relatively easily grown in culture, while adult stem cells are rare in mature tissues and methods for expanding their numbers in cell culture have not yet been worked out. This is an important distinction, as large numbers of cells are needed for stem cell replacement therapies.
A potential advantage of using stem cells from an adult is that the patient's own cells could be expanded in culture and then reintroduced into the patient. The use of the patient's own adult stem cells would mean that the cells would not be rejected by the immune system. This represents a significant advantage as immune rejection is a difficult problem that can only be circumvented with immunosuppressive drugs. Embryonic stem cells from a donor introduced into a patient could cause transplant rejection. However, whether the recipient would reject donor embryonic stem cells has not been determined in human experiments.
AAEA disagrees with President Obama's position of supporting federal funds for stem cell research. Embryos must be destroyed to obtain the stem cells.
AAEA agrees with President Bush's position regarding the use of federal funds for stem cell research.
Source: National Institutes of Health