Some thoughts on stem cell research

Dear Friends,

Every month I pay a large sum of money towards my student loans. I often wonder why, as a dentist, I was required to go through "mini"-medical school. I took embryology, biochemistry, microbiology, anatomy, physiology, pathology, and cell biology...oh yeah and some classes on teeth too! Maybe the reason a dentist needs to know so much medicine is to be able to speak authoritatively on some of the moral issues of our day. (After all, people can't talk back while we are working on the mouth!)

If you have a minute, I will make the case that stem cell research is not all it's promised to be.

Stem Cell research uses human embryos. Many feel that these are human beings in their most fundelmental form...so I believe that stem cell research ought to have clear uses before making a human sacrafice (if at all).

I have taken much text from the National Institutes of Health (Bold and Italics)

http://stemcells.nih.gov/info/basics/basics6.asp

STEM CELLS ...WHAT THEY ARE:

From the NIH:
Stem cells have the remarkable potential to develop into many different cell types in the body. Serving as a sort of repair system for the body, they can theoretically divide without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

So, we can think of stem cells as building blocks. They can become a more specialized type of cell. When our bodies were embryos we didn't have a liver, or a brain, or a pancreas...we only had cells that would later divide and become that liver, brain, or pancreas.

THE PROMISE

Again from the NIH:
Stem cells, directed to differentiate into specific cell types, offer the possibility of a renewable source of replacement cells and tissues to treat diseases including Parkinson's and Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.

For example, it may become possible to generate healthy heart muscle cells in the laboratory and then transplant those cells into patients with chronic heart disease.

In people who suffer from type I diabetes, the cells of the pancreas that normally produce insulin are destroyed by the patient's own immune system. New studies indicate that it may be possible to direct the differentiation of human embryonic stem cells in cell culture to form insulin-producing cells that eventually could be used in transplantation therapy for diabetics.

Replacement cells. All of the fuss over making replacement cells! The problem is that we are dealing with people that have disease! Throwing cells at the site of disease isn't necessarily going to fix the problem.

As you know, I am a dentist. I deal mainly with one type of disease: tooth decay. Now, a person is born with healthy enamel, healthy dentin, etc. Then, a bacterium is introduced into the mouth: usually strep mutans. The bacteria combined with sugar produces an acid which destroys the tooth. Now imagine through a ridiculously expensive procedure I take a living embryo, harvest some stem cells, create new ameloblasts and odontoblasts (the cells that produce dentin and enamel) in a test-tube...and then through an even more expensive procedure (cha-ching) I inject those cells into the area of tooth decay. What's going to happen? The same bacteria that destroyed the mature tooth structure are going to gobble up the fresh "baby enamel" for breakfast.

Ok, so we won't try stem cell therapy in dentistry (although I must say I like the cha-ching factor). Tooth decay is a very simple and well known ailment...and I have already demonstrated that it wouldn't be useful in dentistry. For you science fiction folks, YES I have considered the prospect of growing a new tooth in some freaky petrie dish somewhere...but then there's the challenge of implantation and can you say CHA-CHING CHA-CHING CHA-CHING?!!!

Alright...so the pro-stem people don't emphasize the benefit to dentistry. Instead they have talked about much "simpler" diseases like Parkinson's, Alzheimer's and MS.

And this gets me to our biggest problem: WE DON"T KNOW THE CAUSES OF THESE DISEASES!!!

As many of you know, Michael J. Fox has Parkinson's disease. Parkinson's is caused by the cells of the substantia nigra (part of the brain) becoming destroyed (unknown cause) and as a result dopamine (an important neurotransmitter) levels drop.

So the hope is that stem cells could grow into Substantia Nigra cells and then we squirt them into MJFs brain and voila: no more Parkinson's! But Mr. Fox was born with plenty of his own cells...that were somehow destroyed...and chances are they will be destroyed again. You see, there was a reason his cells were destroyed. It could have been a blood flow problem. It could have been a virus. It could be his immune system. But it is likely that the same process that killed his original cells will kill the new ones.

We have to get at what is causing the disease first! Besides, we already have replacement cells. They can be harvested from cadavers. Go ahead and squirt some substantia nigra cells into a brain and see what happens. My guess is that they have already tried and failed.

The hope is that while doing the research on the stem cells they will be able to unlock the mysteries of the universe and become so knowledgeable that they will uncover the mysteries of all of the aforementioned diseases. But going back to my dentistry example: by studying how enamel is formed will not tell me how it decays. You have to see the bacteria in action...and the sugar...then the light turns on!

Stem cell research will focus on how things are formed...not why they go wrong. It is the wrong approach. If you have a tire that is wearing on one side...you'd be better off checking your alignment not going to the Goodyear manufacturer.

It is irresponsible to promise to find a cure to so many diseases...when most of them have an unknown cause.

Only when we discover the causes of those diseases will we be any closer to finding a cure.


Thanks for reading.



David Alvord DDS