stem cells – Denialism

Adult stem cell lies – everything old is new again

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”

Lifting the stem cell ban – was there any point?

President Obama has lifted the ban on embryonic stem cell research enacted by Bush, but I’m left feeling that this intervention came many years too late.

Pledging that his administration will “make scientific decisions based on facts, not ideology,” President Obama on Monday lifted the Bush administration’s strict limits on human embryonic stem cell research.

…

But Mr. Obama went on to say that the majority of Americans “have come to a consensus that we should pursue this research; that the potential it offers is great, and with proper guidelines and strict oversight the perils can be avoided.”

In making his announcement, Mr. Obama drew a strict line against human cloning, an issue that over the years has become entangled with the debate over human embryonic stem cell research.

As someone who works with stem cells I find this largely an empty, symbolic act, but one that needed to be done anyway. The reality is the damage was done by Bush already, and we’re fortunate that it was only a temporary delay in some of the most important research humans have developed to date.

What a lot of people don’t realize is that in 2006 a revolutionary result was discovered by Japanese scientists led by Shinya Yamanaka at Kyoto University. What they found was the reset button for mammalian cells, the genes that need to be expressed for a cell to revert to a pluripotent state. We wrote extensively about what results in these cells – induced Pluripotent Stem Cells or iPSC – mean for stem cell research and regenerative medicine overall. Basically, the ability to reprogram the cells of any individual to a totipotent state – one in which the cells may make any cell-type or tissue in the human body. Before some fool suggests this was due to Bush remember it was a Japanese group, the research started long before Bush, and it never would have been possible without ES cells from which they culled the critical genes for the transformation.

So why does it matter that Obama has reversed this policy? Not only are ES cells inferior compared to iPSC for human therapies, but wouldn’t it be easier not to upset the fundamentalists that would equate the value of our lives to that of a ball of undifferentiated cells?

Continue reading “Lifting the stem cell ban – was there any point?”

Tumors in a (quack) human stem cell therapy

It’s almost like a bad Yakov Smirnoff joke, “In America you test therapies in animals before giving them to humans, in Russia…” All I can do is wonder, what were they thinking? Injecting stem cells into a kid’s spinal fluid to correct a genetic disorder? Are they insane?

Stem cells, in particular embryonic and fetal stem cells, are useful because they represent cells that are less differentiated than the cells that are working at specific functions throughout your body. Another result of being stem cells is that they are able to divide and proliferate without differentiating or undergoing apoptosis and as cells differentiate towards their final fate they tend to divide less and ultimately commit cellular suicide if they are signaled to begin dividing again – a protection against cancerous growth. The downside of this is that stem cells act, in their normal state, a bit like cancerous cells. In fact one of the assays to demonstrate the pluripotency of a cell (the ability of a stem cell to make many kinds of other tissues) is to inject them into an animal where they will make tumors called teratomas which are (usually) benign growths of cells that represent endoderm, mesoderm, and ectoderm – the three germ layers than give rise to all tissues in the body during development.

As a scientist who works with stem cells, both in culture and in vivo I could have told you this therapy was a bad idea. A year ago Jake explained why this was a bad idea. If you had described this therapy to us, we would have told you exactly what would happen based on scientific knowledge of how these cells act in vivo. The therapies offered to stem cell tourists are frank quackery. They are unproven, untested, unstudied, and unmonitored. And to you anti-FDA libertarians out there, this is what you get when you don’t have regulatory oversight of human therapies. You get stupid quackery. The fact that this kid’s cancer was detected is probably just luck – there are likely many more people who have tried these therapies of desperation who suffered side effects, and possibly even death, but we just haven’t heard about it yet.

Ethical human trials require many things. At the very least, the therapy should have been tested extensively for safety in animals and ideally for efficacy in animal models of the disease. The patients should be selected carefully, should have a reasonable expectation of therapeutic benefit, and after the treatment follow-up should be extensive. Further, in the case of such a novel therapy, the bar should have been set higher before attempts in humans were made. In this case we have a child with a rare genetic neurodegenerative disorder that was experimented on without proper oversight, or a reasonable expectation that this therapy should do anything. Ataxia Telangiectasia is an autosomal recessive disorder in which every cell in the child’s body lacks the appropriate gene which is involved in cell cycle regulation and DNA repair. By what mechanism did they think neural stem cells would have an effect on such a disorder? Would the cells replace the child’s entire central nervous system? Would they miraculously repair the genetic defect? Or manage to insert themselves in just the right places to fix symptoms caused by a universal defect in the the hosts genome? This is magical thinking, not scientific thinking, and further I believe it is grossly unethical and stupid.

It is of no surprise that the careless injection of fetal stem cells into a child would result in tumors. This was a mind-bogglingly stupid act. What’s worse, as we hear more about the damaging quackery being offered in countries without proper regulation and oversight of human therapy we will likely hear more stories like this one.

In the rush to find some dramatic cure for a disease using stem cells it is likely efforts like these will damage the success of legitimate and careful studies in regenerative medicine and stem cell therapies. Injury and deaths from careless stupid quacks using these cells will create and association in people’s minds between stem cell therapies and cancer. We know the obstacles to using these cells in humans. The major one – immune compatibility – may have been solved already. The major remaining obstacles towards implementation of some fairly crude stem cell therapies are going to be (1) differentiating the cells into the appropriate tissues, (2) purifying the cells so that undifferentiated cells aren’t accidentally transplanted into humans, (3) preventing tumorous growth in the transplanted cells (possibly including a lethal gene to reverse the therapy if necessary), and (4) proper anatomic delivery of the cells so they perform a useful function and survive in the host. We know what the problems are. Careful study must include addressing each of these issues and ensuring they are resolved before shoving them into someone’s spinal fluid.

This quackery is not only going to prove harmful to individual human patients, but will likely harm the burgeoning field of regenerative medicine as a whole. For the sake of the patients, and for all future patients that might benefit from well-studied therapies, this quackery must be stopped.