With stem cells once again in the news and White House spokesman Tony Snow saying Bush's veto will be "
pretty swift," it might useful to talk about the science and promise of stem cell research, so that we can understand just what might be at stake.
Anytime you are injured, Adult Stem Cells (ASCs) create new tissue, as best they can, as part of the healing process. You have ACSs in your bone marrow, in your skin, in your liver, and so on. Each of those specialized ASCs can become new tissue, but only within the confines of the tissue they exist within. Liver Stem Cells can become new liver tissues, skin stem cells can become skin, etc. ASCs have limited plasticity.
Embryonic Stem Cells (ECS) can and do become any tissue. That's how you were crafted at the cellular level in your mothers womb, piece by microscopic piece, and throughout your childhood. Embryonic Stem Cells created your heart, your eyes, your brain, and everything else. Because ESCs can become any tissue, we would say they have much greater plasticity than ASCs (Stem Cell Primer here).
Case in point: Spinal cord injury. It is estimated that a quarter of a million Americans suffer from some degree of spinal cord injury with close to 10,000 new SCIs reported each year. The estimated total lifetime medical expenses incurred for these individuals routinely tops one-million dollars1. When the nerve tissue that makes up the spinal cord is damaged, there is very little, if any, regeneration. Neurotopia has more and with pretty pictures:
Stem cells represent a viable treatment option following spinal cord injury. Undifferentiated stem cells excrete a variety of neurotrophic factors that encourage axon growth, promote the replacement of damaged non-neural structures such as blood vessels, promote the breakdown of the glial scar, and temper inflammatory responses. Embryonic stem cells in particular have a penchant for adopting the glial phenotype, that is they will readily transform into the support cells required by neurons (e.g. astrocytes, oligodendrocytes) once they are transfused into the site of injury.
Stem Cell research offers the promise of regrowing damaged spinal cords and for that matter, almost any other diseased tissue. Maybe even entire organs, specifically tailored for the patient, could be produced with applications that flow from stem cell research. The long term possibilities are dazzling; new limbs for amputees; new hearts or livers to replace those destroyed by disease; new retinas or even whole new eyes for the blind; brand new skin, scar-free, for burn victims. The potential breakthroughs dwarf any advance in medicine since the development of general surgery or antibiotics.
We do not know if these dream treatments will become a reality. What's critical to understand is that to develop any of them, we need government funded research into both ASC and ESC. Scientific discovery and innovation is serendipitous. We need to learn how to develop and program stem cells and to do that, a whole array of physiological questions must be answered about how to turn them on and off to become specific tissues and avoid rejection. ASC and ESC research provides that insight, the two work hand in hand. And the end product in many cases will almost certainly rely on research done on both types.
ESC lines come from material stored at fertility clinics which is already slated for destruction. Preventing these blastocysts from being used for research won't 'save' them. It simply means they'll be disposed of in a medical waste facility instead of being used to find cures for disease. The only reason to restrict federal approval of new lines is to appeal to a minority of extremist social conservatives and it comes at the cost of possibly delaying or denying treatment--and in some cases life itself--to millions of people.
One more time for those in the back row: On the left is a blastocyst from which embryonic stem cell lines are made. It's ten times smaller than the dot at the end of this sentence and contains roughly 100 cells. On the right is a human baby, one of many who's life might someday be saved or greatly enhanced by treatments developed from ESC research. Any questions?
Our present federally approved embryonic stem cell lines are aging and contaminated. They're rapidly losing what little scientific value they had in the first place. Much research has been slowed to a crawl or stopped completely because of the peculiar ideological beliefs of a single man: George Bush. This despite the fact that the new, bipartisan legislation proposed in the House and Senate is supported by an overwhelming majority of Americans from both parties. If and when the day comes that a cute kid stands up and walks away from his wheelchair for good, the President and the right-wing culture of death are going to appear about as appealing as the theocrats who imprisoned Galileo.