Can somebody explain the stem cell therapy to a complete laic like myself? I don't mean links to science articles, I mean a description you would attempt projecting at me if we were having a beer.
For me the stem cells are some sort of a magical Wolverine regeneration sauce. Never understood why they even work.
They are some sort of magical wolverine regeneration source. When you have a fertilized egg the first thing it does is start multiplying. But once you have a little cluster of cells they start making decisions (using bits of DNA to communicate) about what they should turn into - a skin cell, a bone cell, a brain cell or whatever. The trick with stem cells is to harvest them and keep them on ice just before they start making decisions. Then you transplant them into an injured body and they're all like 'hey ho, looks like I'm surrounded by nerve cells here so I'm gonna be a nerve cell too' (if you injected them into a spinal column) or 'woot, looks like I'm in a community of liver cells, I'm gonna turn myself into a liver cell' etc. etc.
The biggest problem is that you'd like a whole tank of stem cells that you could dip some injured person into and have them come out fully repaired, but getting stem cells to multiply without turning into anything in particular is a challenge so we have to cultivate them in very small quantities and it's relatively slow and expensive to do that.
There is also research in progress to regress a more-differentiated cell back into a state similar to less-differentiated cells.
Essentially, rather than stopping the cells from making "what I want to be when I grow up" decisions, you're taking a grown-up cell and forcing it to forget all the decisions that its predecessors ever made. It's a bit more difficult.
In general, those decisions are recorded on the nuclear DNA by "tagging" it with methyl groups, like customizing a dictionary by using paper clips to bond together the pages that are least frequently accessed. You can look up the words you frequently need much faster, but you lose the ability to look up anything else in the clipped-together pages.
If you take one of those dictionaries, and remove all the paper clips, it's back to being a completely generalist reference, almost just like a new dictionary, that had never been customized in the first place. The most notable difference is that the old dictionary might have accumulated some damage over the years.
Furthermore, there is a differentiation hierarchy. Some cells only make a few decisions. So even if you can't suck fresh stem cells out of embyros or umbilical cords, there is the possibility that you could liposuction some adipose tissue, separate out the least-differentiated cells, and inject them into other tissues. Those cells could possibly repair bone, cartilage, and ligaments. Or you could crack open baby teeth, or suck out bone marrow, and produce different types of cells. With nerve cells, though, you're out of luck, because there's really no reservoir of cells that can be harvested.
So you take some of those liposuctioned fat cells, chemically treat them to remove all the clips from their respective dictionaries, and try to make them switch to nerve cells by attaching new clips to different pages. Those cells will be cells with your own DNA, but it might just be old, damaged DNA that can't make certain proteins correctly any more.
So the stem cells grow into new nerve cells, and somehow grow all the way through the body to replace the damaged cell? Or perhaps they grow a short nerve cell that connects the two halves of a damaged cell? It sounds like some funky hit-and-miss wiring.
Our adult cells communicate with their immediate neighbors through some pretty complex chemical signalling, and stem cells are receptive to that. It's one of the reasons stem cells are able to cooperatively develop from one single cell into a complex multi-cellular organism. Each stem cell carries the complete blueprints for a human being, it just needs to access and activate them based on the signals from it's neighbors.
In fact, pregnant mothers have been found to have fetal stem cells in their blood stream, which target areas of injury and are thought to be repairing them, even within the brain.
As an aside, it should be noted that all cells carry the complete blueprint for a human being. The open question for a long time was whether it would be possible to push adult cells 'back' in time to a state where they could become another type of cell. Thanks to the work of tenacious scientists, we know that the answer is yes! It can be done. Methods have been discovered to coax already differentiated cells to become pluripotent. That is, adult cells that are already of a specific 'type' have been reprogrammed to become stem cells.
I in no way intend this to be an argument against embryonic stem cells. I just find it to be extraordinarily interesting and an intriguing avenue for further development.
The trick is also making sure they don't get too excited and build a tumor, which would make things really bad.
But yeah, they're almost magic, except we understand it. Which is probably why large sectors of the religious public finds them so abhorrent: they take away yet another arrow from the inscrutable Fate they worship, they lift another bit of veil from the mystery of our existence. And it's a shame, because the objective need for strict regulation will be hampered by constant calls for pointless bans.
> But yeah, they're almost magic, except we understand it. Which is probably why large sectors of the religious public finds them so abhorrent: they take away yet another arrow from the inscrutable Fate they worship, they lift another bit of veil from the mystery of our existence.
No, that's completely and totally not it. Folks oppose embryonic stem cell research because they believe both that embryos are human beings and that innocent human beings should not be killed. That's it.
Note that Mr. Bush continued to fund adult stem cell research, and continued to fund research on existing stem cell lines; what he didn't do was continue to fund the destruction of more embryos.
You may disagree with the idea that an embryo is a human being, and you may disagree that innocent human beings should not be killed, but you mayn't be uncharitable to your opponents.
Really? Religious people, under it all, just don't like unveiling mysteries with science? It couldn't be that they don't like treating human embryos as commodities?
As a computer scientist, I have no expertise in it. But my understanding is that a stem cell is an 'undifferentiated' cell. It hasn't been 'programmed' yet, to tell it what it should grow into. And as such, can grow into any type of cell in our body. I just don't know how we actually tell it what to grow into.
For instance, as an embryo, you start as a single cell, it divides, eventually some of those cells need to start specializing, but until then they all have the potential to be any type.
From my understanding, stem cells are like cells that have not picked a specialty yet. So they can become the cells necessary to repair a damaged area once they are introduced.
For me the stem cells are some sort of a magical Wolverine regeneration sauce. Never understood why they even work.