It’s come time to lie about science again – this time about the reality of embryonic stem cell pluripotency – and some of the old lies are coming back out of the storage shed. For instance, Andrew Breitbart on Real Time last night, and in a video from (liar for Jesus) Tony Perkins of the Family Research Council, I’ve heard about how adult stem cells have cured or treated 72 diseases. Oh and embryonic stem cells, they’ve cured none. It’s been a while since we’ve seen this adult stem cell nonsense.
I had to jog my memory for a minute, I knew this was a lie, but it had been so long since I heard it, that I really had to think about where I had heard it from. Oh yeah, this nonsense list that was famously cribbed by Ann Coulter from a right-to-life group.
To understand the problem with this list and why these citations don’t say what they think they say, we have to learn a little bit about adult stem cells and a big scary word – transdifferentiation. Adult stem cells, which exist in many tissues throughout your body, have specific jobs to perform for the human body to continue to function. Hematopoietic (blood) stem cells make all the red blood cells, white blood cells, and platelets you need to as they are continuously lost or degenerating as part of their natural life span. Stem cells in your gut continuously replace the lining of your intestines as it wears down from the harsh process of breaking down food. There are stem cells that have been isolated from most tissues that function as a repair and maintenance pool of cells to keep our organs functional. Not all organs have a ready pool of stem cells, and most stem cell populations, with the notable exception of blood stem cells, are hard to harvest without risking injury to the host.
However, while these cells are great at doing their job, the issue with adult stem cell research is, can they do another stem cell’s job? That is, instead of making just blood, could a hematopoietic stem cell make, say, an insulin secreting pancreatic cell? The answer, despite some initial promising results around 2001, is no. While hematopoietic stem cells may be able to make some other mesenchyme or connective tissue cells from the mesodermal germ layer, it doesn’t appear that we can make such adult stem cells transdifferentiate – or make a type of cell from another embryonic germ layer. This ability is what is meant by totipotency. The ability to differentiate not just into one of the three major tissue types (mesoderm, ectoderm and endoderm), but all three of them.
So, what is up with this list then? They have 72 treatments using adult stem cells!
No they don’t. This is a lie. They really only are describing one treatment in most of these list items. That is, hematopoietic stem cell replacement of marrow being used in the course of treatment of many diseases. The hematopoietic stem cells are not treating these illnesses, they’re letting us use chemo, or irradiation, and then replenishing the patient’s blood supply. In other words, they’re doing what a good blood stem cell does, replace blood. They’re not treating the disease at all.
Let’s take a look at some of these references.
Continue reading “Adult stem cell lies – everything old is new again”