Much Ado about Stem Cells

For the past three months, a major story in the American media was about a missing political intern called Chandra Levy. The Levy story ran on incessantly as if this was a first time an adult had vanished into thin air. In reality, thousands of adults vanish each year in the US, many of them are recovered, and most are dead. However hundreds are not found, ever. Some of these cases are reported in local media, but missing people news reaching the national media is non-existent. Of course Ms. Levy’s connection to a congress-critter makes the story even more salivating.

While Ms. Levy was at the top of the news, the US president, Mr. George W. Bush was battling congress over his policies. After obtaining a tax cut, the president has been working hard on the rest of his short-term agenda. He wants significant changes to the “patients bill of rights”. He is promoting a somewhat radical energy policy that includes fresh oil drilling in some pristine parts of Alaska. More recently, he has been gallivanting around the world spreading his agenda on scrapping the anti-missile treaty and the Kyoto Accord. After accumulating enough frequent flier mileage on Air Force One, Mr. Bush returned home (July 25^th), wrestled with Congress some more and then went on vacation (Aug 7^th). While most of these issues are of significant importance (good or bad) on the US and the world economy, the Levy non-drama seemed to receive more attention.

While on vacation, Mr. Bush’s mind turned to the subject of stem cells. He agonized over it. He slept over it. He stopped sleeping and spent sleepless nights over it. He talked to experts, religious leaders, scientists and advisors. Eventually he came to a compromise decision. On August 9^th Bush went on nationwide TV, for the first “prime time” nationwide address of his presidency, to announce to the world that the US Government would provide funding for stem cell research, with certain limitations. This announcement, swept Ms. Levy off of the media focus. The announcement was hailed as the “defining moment of the Bush Presidency” by the misguided media. And a brand new issue was born—stem cell policy according to Mr. Bush.

What is this entire hullabaloo about? Why are stem cells more important than energy policy, healthcare reform, missile defense and the environmental policy? Why should one person’s view of stem cell research have that much impact on the future and well being of mankind? Is the Bush policy really so important? Is this what defines the US presidency? The answers are actually quite surprising.

Cells are the basic building blocks of life on Earth (and possibly beyond). We consist of cells, trillions and trillions of them. There are of course, many kinds of cells. Hair cells make up our hair. Similarly, there are brain cells, bone cells, skin cells, muscle cells, fat cells, blood cells, heart cells and so on. There are about 10 trillion cells in a human body and there are about 200 different types of human cells. A cell belonging to a specific type of cell (brain, bone, hair and so on) is called a “specialized” cell.

Cells are quite complicated things. While bacteria are single cell organisms, the bacteria cell is significantly simpler than a human cell. Cells are made of quite complex substances such as protein, DNA, enzymes, and various other substances. Cells can reproduce—cell reproduction happens when one cell splits into two, and there are at least two mechanisms of cell reproduction, called mitosis and meiosis.

Most human cells that multiply produce cells of the same kind. This is particularly apparent in growing humans. As a child grows, his or her muscle cells produce more muscle cells, bone cells produce more bone cells and so on, making a 7 pound baby grow into a 150 pound adult. In general specialized cells produce more specialized cells.

Of course, the reproduction of specialized cells begs the question, where did the specialized cells come from? When a human is conceived, there is only one embryonic cell. From this single cell how did we get over 200 different kinds of cells forming the adult human? The missing link between the embryo and the adult is the “stem cell”.

The single cell in the human embryo is an embryonic stem cell. Stem cells can multiply and produce more stem cells as well as more specialized cells. In the case of human formation, at first the embryonic cells multiply to form more embryonic cells. Then things start getting more specialized and some of the embryonic cells become skin cells, some turn into muscle cells some turn into specific organs and thus a human is formed. Stem cells are hence, significantly more powerful than specialized cells.

Not all stem cells are created equal. Human embryonic cells are obviously capable of producing every type of human cell. Hence this kind of cell had the potential of totality and is called “totipotent” cells. Some stem cells are not that powerful and can create most any specialized cells, but not all of them. These are pluripotent cells. Lower down the status ladder of stem cells are cells that can only reproduce a small number of other cells, and these are called multipotent cells.

The embryonic mass that forms the nucleus of a human being consists of mainly totipotent cells and pluripotent cells. Stem cells are however not only contained in embryos and children but also in adults. The adult stem cells are the multipotent kind. For example, blood stem cells are cells that reside in our marrow and these can produce red blood cells as well as white blood cells. 

 The battleground of stem cell research is to harvest the hard to get totipotent and pluripotent cells. The imagination runs wild on what can be done with them. Maybe, we can grow humans in the lab. Well, if that is not too exciting, we can grow body parts in the lab. By managing the reproduction of the stem cells, we can make them transform into a heart, or a liver, or a stomach, or maybe a brain. Then we can use these replacement parts for transplanting failing parts. Need a new heart? What brand would you like? How about a cheap generic one, or a fancy feature-laden one?

Less dramatic and more plausible possibilities are methods of coupling stem cell technology with genetic engineering giving rise to cures for a host of haunting incurable diseases. Parkinson’s, Diabetes, Alzheimer's, Multiple Sclerosis and so on may be easily cured. The possibilities are wonderful. So why don’t we go full steam ahead with stem cell research and wipe many terrible tragedies off of the planet?

Firstly, research is not a sure shot. Yes, stem cells have a lot of “potential” but potential does not translate to reality. The list of things with wonderful potential that dialed to deliver the goods will fill volumes. For example, in 1980 we thought bubble memory technology would fill out computers with limitless storage power. Did not happen. In 1990 everyone thought optical computing would sweep the digital computer off the face of the earth. Did not happen. Many inventions did happen, but most did not happen as expected. Stem cell research currently seems to have substantial potential. The current scientific thinking is that stem cell research will deliver some miracles, but what they actually may be is not at all clear.

Secondly, there is no current law or restriction or ban against stem cell research. Given the Bush policy, does that not seem surprising? Scientists are free to study stem cells and their potential. Even after what Bush thinks or says, the government does not limit stem cell research. The action by President Bush, limits the ability of the US Government to provide money for stem cell research, when the stem cells have been obtained by abortion, purposeful creation of embryos for research and some other stipulations. That does not mean abortions cannot be used to obtain stem cells, but that such a procedure cannot be billed to the US government.

The reasoning behind such restrictions is due to many deeply religious convictions about the sanctity of human life. Not only Mr. Bush but also by a large number of US taxpayers holds this belief. Human embryos not only have the potential to cure dreadful diseases, but have the potential for creating humans. Destroying embryos (for any purpose, scientific of not) offends the sensibilities of many humans. They pay taxes and do not want to promote embryonic research out of their contributions.

Private industry is still free to harvest aborted tissue. Stem cells are also easily available from placenta blood. Stem cell research can continue unhampered the world over. In the US, the US government cannot provide funding for research for any procedure that involves destruction of the human embryo (the actual stipulations are a little more specific and complex). Is this policy an earth shattering event and the key defining history moment in the legacy of George W. Bush? It may just be a tad more interesting than the story of Ms. Levy.

Partha Dasgupta is on the faculty of the Computer Science and Engineering Department at Arizona State University in Tempe. His specializations are in the areas of Operating Systems, Cryptography and Networking. His homepage is at http://cactus.eas.asu.edu/partha.