Oct. 2, 2000 -- Never mind urine and blood tests to detect performance-enhancing drugs -- with what's coming down the pike, the future of drug testing in sports could call for much higher-tech intervention. The International Olympic Committee's World Anti-Doping Agency (WADA) predicts that gene therapy will be the next big thing among those athletes willing to do anything for the gold.
"It certainly is possible," says Inder Verma, PhD, president of the American Society of Gene Therapy and a professor at The Salk Institute in La Jolla, Calif. "You could take growth hormone or erythropoietin (EPO) from [a person's] cells and deliver it to the same person. Whether this is going on now, I don't know, but it is perfectly possible."
As medical research untangles our genetic code in a noble attempt to understand and cure disease, healthy but unscrupulous opportunists may stand poised to exploit the findings. It's certainly not a new concept. Athletes have been manipulating medical knowledge to their advantage since long before steroids came into vogue. The current trend among would-be Olympians involves injecting strength-enhancing human growth hormone (hGH) to pump up muscles or endurance-boosting EPO to super-oxygenate the blood.
There has been controversy surrounding drug testing at the Sydney Olympics. Who should be tested? Who should pay for it? Does it really work? "Growth hormone is very hard to detect already," says Verma. But for the most part, blood and urine tests (albeit highly sensitive, expensive ones) can and do weed out those who've ingested or injected illegal substances.
"The reason they can check for EPO now," Verma tells WebMD, "is that the version synthesized and sold [is slightly different] than EPO [naturally produced in the body]. This causes an antibody reaction and makes it distinguishable." But when a person's own genes are delivered, and the athlete's body then produces more of the performance-enhancing factor, it's a very different story.
"If someone is absolutely bent upon doing it," says Verma, "I've racked my brain and posed the question to colleagues, and I can't come up with a way to detect it. If you take a gene for producing EPO and put it into the athlete ... the protein produced would be no different than the [person's own] protein. It would be exactly the same." Exactly the same -- and thus completely undetectable.
Even high-tech molecular tests like PCR would be worthless unless you knew the gene delivery site, says Verma. Essentially, you'd need a full-body PCR, Verma says. "You could inject the gene in any number of places -- the muscle, the big toe, the liver, the lung, anyplace. And you could only detect it if you know where [it had been injected]. The genetic 'message' is not in the blood. The only thing we could detect in serum is that the person has more EPO [than normal]."
That might be suspicious, he says, but it isn't entirely unusual. Even in a couch potato, infections can dramatically increase red blood cells, as can traveling from low to high altitude. If somebody wanted to cheat using EPO, says Verma, there are any number of seemingly legitimate excuses to explain an usually high level. And officials would be hard-pressed to disprove them.
Right now, hGH and EPO are the most likely candidates for gene therapy abuse, Verma tells WebMD, but he doesn't rule out a host of as-yet-undiscovered agents. Researchers "could [identify] an enzyme that would give a greater degree of stamina by reducing the heart rate and allowing you to breathe more oxygen in, for example," he says. As the Human Genome Project unfolds, the list of potential performance-enhancing genes is bound to grow.
For that knowledge to become a doping tool will, of course, require collusion on the part of the medical community. Unfortunately, concedes Verma, "this happens all the time. In East Germany, when they started doing doping with steroids, it was clearly done by doctors." That might be ascribable to a totalitarian government, he says, "but in a capitalistic society, doctors might do it for the money. We're no different than [anyone else]."