NPR Science Friday—June 17, 2011
Scott Rodeo, MD, is an orthopedic surgeon and co-chief of sports medicine and shoulder service at Hospital for Special Surgery. He's also associate team physician for the New York Football Giants.
IRA FLATOW, host: You're listening to SCIENCE FRIDAY. I'm Ira Flatow. A year ago, Yankee pitcher Bartolo Colon was no longer pitching for a major league team. Closing in on 40 and plagued with injuries, it seems like the former Cy Young winner's career was just about over.
But after signing with the Yankees this year, Colon's career seems to be in full swing again. He's won five games. He has an ERA, an earned run average of 3.1, and although he's currently sidelined by an injured hamstring, he's on pace for a better season than he's had in years.
What happened? Well, we're not quite sure because his amazing comeback is being attributed, at least in part, to a controversial medical treatment, a treatment involving injecting cells taken from his own body back into spots where he has injuries. The cells then repair the damage.
Colon reportedly had the procedure in April of last year in the Dominican Republic, and while the procedure is not itself illegal, Major League Baseball is looking into it to make sure no banned substances like human growth hormone were used.
FLATOW: Scott Rodeo, M.D., is an orthopedic surgeon and co-chief of sports medicine and shoulder service at Hospital for Special Surgery here in New York. He's also associate team physician for New York Football Giants. Thanks for talking with us today, Dr. Rodeo.
Dr. SCOTT RODEO: Thanks for having me.
FLATOW: Dr. Rodeo, I know there are some experts who take issue with calling these actually stem cells. What is your view on this?
RODEO: Right, there's a lot of variability when you talk about these kinds of cells and cell-based therapies. Cells can be - a true stem cell, kind of by definition, to be a stem cell means the cell can self-renew, it can kind of renew itself, and it can differentiate into a number of specialized cells in the body.
And there's wide variability in the ability of different types of cells to do that. So, truly cells that are embryonic, or so-called pluripotent cells, can form most, but not all tissues on the body. Most of these cells are taken from adults, such as in this case - I don't know any details about Colon, so I can only comment generally - but cells taken from fat or bone marrow, as Dr. Lehman mentioned, those are typically multipotent cells.
That means they can generate a limited number of cells, you know, cell types in the body. So tremendous variability. When you talk about stem cells, we need to really define what are we talking about, and part of the difficulty in studying in this area, is there's such tremendous variability in the types of cells that are used.
FLATOW: Dr. Rodeo?
RODEO: I'll start by saying I think it's compelling - - you know, the underlying biologic rationale makes sense. It has tremendous potential. It is safe. It's cells, or blood in the case of PRP, from the individual. There's just a lot we need to know more about the exact cell types we're putting in.
My cells are different than your cells. So how do an individual's cells really function? What do we really put into the body in different sites, and then how do we stimulate those cells? PRP, exactly, might ultimately combine PRP, which brings in the different growth factors and things, with cells.
So cells by themselves may not be enough. The PRP by itself may not be enough. The two together may have some real potential. We just need better data as to how to best use this for different anatomic sites. Different tissues are different as well.
FLATOW: Why is there no good data? Why are there no good studies about that?
RODEO: We have a good amount of animal data. Human data, though, is much more limited. It's hard to do high-level studies. Frankly, it's a newer technique as far as some of the contemporary techniques have only been around for a couple years. Studies are costly, and I think we've identified now what the important variables are, and now we need to do those studies.
We simply need to collect careful data on our patients. As Dr. Lehman mentioned, they're being used a fair amount, and that's probably fine, they're safe, but I would just advocate that we carefully study those patients in whom we use this and really look at what we're putting into the patients so that we can truly understand what is effective, what is not, what parts are effective, to really start to have a more refined understanding of this whole area.
FLATOW: Dr. Rodeo, do you agree that the stem cells, the PRP stuff, does give positive results?
RODEO: I've seen some positive results. I think there's a fair amount of variability out there, but I think there can very much be positive results, and I would be optimistic about it. I think, you know, we need, we just need more information as to really the best cell type, and that may vary for different anatomic areas.
You know, if you're injecting a shoulder versus an elbow or different tissue types within a given joint, so it's a lot of variables to understand still.
FLATOW: Baseball is investigating and interested in it not because it might be an illegal procedure, but possibly there was the use of human growth hormone, which is a banned substance in baseball. Why would that be mixed into this cocktail of what's happening? What would be the advantage of that if it was at all used?
RODEO: I think growth hormone in general, people have used for years, athletes have used for years. And clearly people feel that that's going to enhance your rehab and enhance your ability to strengthen.
I think the other issue, though, is you've got a pitcher and a part-owner of an NHL team, and your athlete goes to the Dominican Republic. You have a contract, et cetera, et cetera, and then your athlete is kind of out of your care and treatment. So I think there are some other issues.
RODEO: And so, you know, and it makes hard to interpret the effect of any cell therapy if you also have another factor that may have contributed or lead to the positive result.
FLATOW: … We talked here on the show about using pluripotent stem cells to treat diseases, and one of the concerns that came up is tumors. You get cells that can divide uncontrollably. How do you know that this wouldn't cause a tumor in these kinds of cells that are being used?
FLATOW: Dr. Rodeo?
RODEO: Yeah. I could say that the issue comes up with very, very undifferentiated, very primitive cells, that that risk is there. That risk could only be that the most primitive cells are cells that come from a fertilized, you know, fertilized egg. Those are truly - those cells can make any cell type in the body. Then your next level is embryonic stem cells, where there may be some risk. What we're talking about here, these are adult-derived cells. The risk is essentially minimal or no risk, because these are so-called multipotent cells. These are - they're much more limited in their ability to form different types of tissue, and as such, the tumorigenicity is minimal, and really not been a big concern.
FLATOW: And could - why not just use this in athletes if it does pan out? And this is also - is being tried and you can, you know, convince people to do really good testing about it, could you not use this for different parts of the body than just the, you know, the shoulders or the knees and things?
RODEO: You surely could. The biologic rationale is very compelling. It has great potential. In our area, we look at it for healing meniscus and cartilage and tendon and ligament and certainly bone, as was mentioned. So, again, great potential. We just need to learn more about, particular cell types for different tissues, how to stimulate them. It could have probably different - different requirements for different tissue types.
FLATOW: And who would do the research? Drug companies usually do drug research because they can sell a drug. I mean, is that one of the problems here? There is really no big money to be made on doing something like this?
RODEO: Good question. There are some commercial systems that are available to help one do this, so there is some commercial part of this. I think good research should be done in your academic medical centers, where it's frankly done independently - independent from research. But at the same time, research is expensive. So we need funding from our, typically, federal dollars from the NIH or private foundations, so you bring up a good point. We need research.
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