Stem cell pioneer does a reality check

Thomson: If you think about the kind of transplantation that people talk about — say, Parkinson’s — it’s a very complex disease. The brain is a complicated organ. It may be possible someday to transplant cells and treat that disease. But it’s clearly going to be challenging. When you think about it, that’s a pretty crude thing to do anyway. What you want to do is understand how the disease happens in the first place, and you need to prevent or slow its progression to the point where it’s not going to be relevant anymore.

Up until now we’ve never had dopaminergic [dopamine-producing] neurons from humans that we could study in the laboratory. They simply didn’t exist. So human embryonic stem cells already give rise to these dopaminergic neurons with very high frequency. I hope that they might be useful for transplantation. They may not be. I mean, you have to be realistic about it. But in terms of a basic model to understand what’s happening in the disease, it’s unparalleled. I think what will happen is that people will understand the basic biology of the disease using this model system, and they’ll come up with therapies, and you won’t even know stem cells were involved in creating those therapies. …

I think that’s the theme for most diseases. There are some that really should work, like diabetes. There’s already a transplantation therapy for that. There’s just this mismatch between the availability of tissue and the need: There’s a couple of thousand appropriate pancreases donated in the United States every year for this procedure. You need two for each patient, and there’s over a million people with diabetes. It’s a complete mismatch.

So you’d think if you could just come up with a better cell, then that would go directly into transplantation. And it probably can. The problem is the safety issue. If you take cadaver tissue and take the islet cells out, you’re not forcing them to divide a lot in culture. They’re going directly into a patient. So the chances of introducing a cancer are pretty small. It’s a negligible risk.

But with stem cells, if you manipulate them in culture for a long time, they will accumulate mutations. It’s a fact of life. It’s just a question of differences in the rates. If you accumulate enough of those mutations, you could actually create a cancer.

This has nothing to do specifically with embryonic stem cells. It’s just any cell you put in a tissue culture. But if you’re going to take those cells and put them into somebody’s body, you want to make really, really sure you have some way of dealing with that – because if you’re diagnosed with diabetes and you’re 6 years old, you’re going to live a very long, productive life. It’s a pretty normal life until the end. … But you don’t die from cancer in a couple of months.

So that one is like, “It really should work, and there’s no reason why it can’t work” – but the safety issues are high enough that I suspect it will take a long time to get to the clinics, because you don’t want to create a disease that’s far worse than what you’re trying to cure.

MSNBC: Does it concern you that there are people who say, “We’re this close to solving this sort of disease with stem cells, so let’s pass this legislation”?

Thomson: Yeah, it’s unfortunate. There are clearly exceptions on both sides, but most of the people who oppose this research, and most of the people who support this research, do it with a profound amount of misinformation. It’d be very nice to clear up that information as much as possible. You can still make an informed choice and be for it or against it, but at least it’d be based on the real facts.

When President Bush was elected, there were about eight months when stem cells were on the cover of every major newspaper in the United States, because it was prior to 9/11 and it was a slow news period, basically. Nonetheless, when people did polls right at the end of that period, the average American really didn’t understand embryonic stem cells, despite that tremendous amount of press coverage, because it just became this political question.

I guess the news media aren’t really the media to educate. The news media failed in that role. … I don’t know how to change it, because every time I have an interview with some guy and try to go through what the science is, they talk about curing Alzheimer’s.

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