BLIND FAITH vs. SCIENCE
By Ayesha Khanna

Stem cells have become a magical term these days, eliciting the kind of reaction that the Muslim world had to Salman Rushdie's Satanic Verses. It was an open secret that the majority of the Muslims ranting and raving against the book had never even held a copy of it in their hands, let alone read a page. Lest ignorance shove stem cell research into a basement for years, I thought it would be beneficial to go over the science and politics of stem cells.

THE SCIENCE

What are Stem Cells?
Stem cells are cells that have the potential to develop into any kind of specialized cells, such as blood cells or liver cells or neurons.

There are two main types of stem cells:
(i) embryonic stem cells
(ii) adult stem cells

Embryonic stem cells are cells extracted from an embryo which is a few days old [at a stage known as blastocyst]. Embryonic stem cells have the potential to become any kind of specialized cell in the body. Adult stem cells are cells that are peculiar to a region in the body, such as the liver, and can give rise to a number of different specialized cells within that region.

Stem cells become specialized cells through a process known as differentiation. There are two catalysts for differentiation - genes and the microenvironment surrounding the cell. This means that the cell will receive internal signals from its genes on when and how to develop into a heart muscle cell, for example, and will also react to external signals, such as those triggered by physical contact with other molecules in the region. In the lab, scientists massage the stem cells using a number of gene and chemical manipulations to create the specialized cells they are interested in investigating.

How are Stem Cells Generated in the Lab?
An embryo can be created by fusing an egg with a sperm in-vitro [in the lab]. The resulting embryo can be placed in the womb of a woman resulting in a pregnancy, or it can be kept in the lab for research purposes. The embryonic cell divides itself into two cells, and then into four and so forth as it grows. After five or six days, the embryo becomes a blastocyst. At this point, the researchers break down the outer wall of the embryo and extract the inner cells [usually about 30 cells], known as stem cells. These inner cells are then kept in a culture dish for several months and they continue to divide without differentiating, i.e. they maintain their ability to become specialized cells. After about six months or so, when millions of these embryonic cells have been cultured, they are referred to as an embryonic stem cell line. At this point, the cell lines can be frozen and shipped to other labs for experimentation and research.

And Then There is Cloning ...
Cloning is probably the only other word that generates more controversy and buzz than stem cell research in popular press and debate. One way to generate a regular supply of stem cells would be obtained by copying or cloning embryos specifically for their stem cells. This is not equivalent to cloning human beings; the cloning is specifically for the generation of the inner cells of the blastocysts. It is obviously a much more efficient method than fertilizing and creating an embryo from scratch every time one needed to create a stem cell line. However, the process of therapeutic cloning of stem cells has raised unbelievable uproar amongst conservatives in the US and everywhere in the world, leading even some countries that allow stem cell research to ban 'human' cloning methods used for generating stem cells.

TIP: Check out this excellent short video on stem cell research by NOVA, which includes an explanation of how stem cells are created in the lab.
Or How Embryonic Stem Cell Lines Are Made An online animation from the Dolan DNA Learning Center, Cold Spring Harbor Laboratory.

The Promise and The Evidence
The most potent promise of stem cells is that they can be used to repair and replace degenerative cells in any part of the body. Many scientists believe that stem cell research has the potential to radically change the topography of medical treatment. Specifically, the ability of stem cells to replace cancerous cells, and nerve cells injured in spinal cord accidents are two examples of treatments that have received popular press recently. This is achieved by injecting stem cells in the damaged area and stimulating them to produce new specialized cells needed to replace the damaged cells.

One example of a promising use of stem cells is in the creation of new neuron cells for patients suffering from Parkinson's disease. Sufferers of Parkinson's disease experience difficulty with movement because specialized brain cells, known as dopamine neurons, die or become damaged in the brain. Dopamine is a chemical produced in the body that regulates, among other functions, smooth muscular movement. There is currently no cure for Parkinson's disease; one potential cure is to replace the dead brain cells with new healthy dopamine producing neuron cells using stem cells.

NOTE: It is important to keep in mind that stem cells can be rejected by the recipient's immune system as a foreign body, so extensive tests need to be done to match the correct stem cells with the recipient, ensuring that they are similar enough not to be rejected. Good matches are determined by doing a tissue typing test using blood samples from both donor and receiver. The test compares HLA antigens, which are proteins that reside on the surface of certain immune cells, of the donor and the recipient. If the HLA antigens are identical, then this is a good stem cell transplant match.

One place where stem cells are already used extensively is in bone marrow transplants to treat leukemia. Leukemia is the uncontrolled proliferation of white blood cells or leucocytes in the body. These damaged white blood cells, usually crucial parts of the body's immune system, become useless in fighting diseases and begin to interfere with the functions of other organs. They are created by adult stem cells in the bone marrow; a successful treatment of leukemia involves a transplant where all the patient's damaged white blood cells and bone marrow are destroyed by chemotherapy and radiation, and then replaced by the bone marrow stem cells of the donor. New healthy white blood cells are then created by the donated stem cells.

THE POLITICS
In July 2006, President Bush vetoed a bill approved by Congress that would lift the ban on federal funding for new embryonic stem cell research [note that adult stem cell research is not a contentious issue]. The reasoning of the President, along with all those who oppose embryonic stem cell research, is simple: we will not destroy life to create life. In case there is any confusion, the blastocyst which is about the size of the dot on this ' i ' is the life that is being discussed here.

To Fund or Not To Fund
It is important to remember that a ban on federal funding is not a ban on embryonic stem cell research. In fact, researchers are free to perform this research as long as the federal government does not pay for it. However, if you are a scientist getting funded by the government, as so many researchers are, you are liable for up to several years in jail and a hefty fine if you use that money for conducting embryonic stem cell research. Also, there are a few existing stem cell lines that are eligible for use by federally funded researchers; the ban is just on creating new stem cell lines.

California Gov. Arnold Schwarzenegger of California reacted to Pres. Bush's veto by allocating $150 million from his state's general fund to stem cell research scientists. So there are other sources of funding, both private and state level, for research in this field.

Harvard University, the world's richest university, recently announced that it will use private funding to harvest stem cells to try to fight blood diseases like leukaemia and diabetes using cloning as a technique to create fertilized embryos.

For scientists, there is always the option of going to other countries which have flexible policies on this kind of research. India, with two genome sequencing centers is one such example.

TIP: Check out this world map showing countries with flexible policies on stem cell research.

Pro-Life
Meanwhile, the EU Parliament went through a heated debated itself in June 2006 on whether to continue its funding of stem cell research. A number of its fervent Catholic members, like Poland, Slovakia and Italy, called for the exclusion of stem cell research from European spending. However, by a narrow majority, the Parliament voted in favor of spending its allocated research money on projects that included stem cell research.

The Church's distaste for such research was highlighted when Vatican-based Cardinal Alfonso Lopez Trujillo was quoted as saying that stem cell research was "the same as abortion".

Thus, it seems that for those against stem cell research, it pretty much comes down to blind faith: "Is a tiny cluster of cells life i.e. does it have a soul?" is similar to the question "Is there heaven and hell after death?" Because logically, it makes no sense to equate the potential to save a person's life to the death of a group of cells or a soul [a highly overrated notion best left to philosophy and literature anyway].

To provide you a framework for thinking about the question, if you are still confused about the ethics of stem cell research, I'll use the example given by a Harvard professor in a NOVA documentary on the subject:

Imagine you are sitting in a lab with a young child. The lab contains a small fridge containing one hundred frozen embryos. Suddenly, there is a fire in the lab and you can either grab the child and run out or grab the small fridge containing the embryos and run out. What would you do? Your answer should answer the question whether you consider a child's life equal to the life of an embryo.

Links:
National Institute of Health website on stem cells
NOVA video on stem cell research
Harvard Stem Cell Institute
Stem cell tutorial, Genetic Science Learning Center, University of Utah
World map showing countries with flexible policies on stem cell research
World map of stem cell research centers

Image Courtesy Corbis