Stem cell research is making a comeback as more and more people fall under the snake oil pitch about massive cures coming from innocent emrbyos. The Corner at NRO has an item that demonstrates how bad this is becoming.

Senator George Allen just basically came out for the legislation easing embryonic-stem-cell restricitions on This Week. Use “surplus” embryos from IVF clinics if you need to, don’t create new embryos.

Embryonic Stem cells have a long way to go to prove their potential before we go on a rampage of finding embryos to ‘harvest’. Contrary to popular myth, science has not come close to controlling the genetic code in a manner that will allow doctors to control the transformation of a stem cell into a replacement cell for illness and damaged tissues. Until they CAN demonstrate this control there is no need to go out killing.

What people do NOT understand about stem cells is WHY they have potential. Unless you understand the mechanism scientists are relying on for treatments you cannot understand the daunting tasks ahead of them to realize these treatments.

The attraction of embryonic stem cells is they are the precursors for all types of cells in the human body. During the growth of the embryo into a fetus the embryonic stem cells differentiate into specific cell types to make up tissue, structures, organs etc.

Adult stem cells are cells that retain this ability to differentiate to a smaller spectrum of cell types.

The problem is no one knows how to control the differentiation. And differentiation is a VERY complex process of triggers (environmental, biochemical, precursor elements and other conditions) to start generating the elements key to the new cell types, monitors (same as before) to time the creation of these elements in their proper quantity and location, and stop events (same as before to start the next sequence. The only way to really control this is to do the decades of work to learn how to control each step for creating each element (in the proper order) in order to direct a stem cell to differentiate into a target cell type. And this initial research can be done on the stem cells of ANY mammal for the most part. It is a mechanical process that should be the same or nearly the same for something common like hair or skin.

Because this will take decades, the scientific community has been trying the shotgun-pray approach. This entails trying to ‘prepare’ the stem cells with a specific mix of starting conditions (again: environmental, biochemical, precursor elements, etc) and then applying the stem cells in vivo (into a living organism) to see if they can jump start the differentiation (creation) of the missing or damaged replacement cells. The combinatorials of factors makes this gamble (which is all it is, using up embryos in the hope of accidentally hitting the right combination) less likely to achieve anything than the detailed approach of working it out. But that is why there is a need for massive numbers of embryo’s – they are nothing more than more lottery tickets.

To give the layman some idea of the odds, there are 30,000-40,000 genes in the human genome (which took decades just to identify). Who would play a lottery where you needed to select from 40,000 numbers looking for a combination, in order, of 30 numbers? But that is not the whole picture. Add in all the preconditions and timing and the number balloons. If each step in the differentiation required 5 preconditions plus one timing precondition that is 6 combinations on top of the 40,000 required to pick. Each differentiation may need 1-100 steps…

The odds are ridiculous. So what we need is to define a minimum level of competency before we go raiding embryos. Scientists should be able to demonstrate they can control the transformation in lower level mammals first (which they must do in ANY OTHER treatment). Whether they get there through hard luck or winning the lottery doesn’t matter. They have decades to go to prove the efficacy of their approach before we need to harvest human beings.

UPDATE: I should have also mentioned the problem embryonic stem cells have relative to adult stem cells – tissue rejection. If you could coerce the patient’s own adult stem cells (or any cells) to differentiate into the needed target cells you eliminate the problem of rejection. You also eliminate the problem of mixing genes. If cells from one person (embryo) are used to create replacement cells you have now combined two sets of genes. These new genetic combinations may cause all sorts of problems as the patient’s genes fight with the donor’s gene’s to control the physiology of the patient. You want to see serious genetic problems the like we have never seen? Try mixing gene’s in this manner.