Not Just Sparing the Nerves, But Giving Them Extra Protection
Surgeons who perform the “nerve-sparing” radical prostatectomy (developed at Hopkins by Patrick C. Walsh, M.D.) take great pains to preserve the tiny nerves that are responsible
for erection. But these nerves are notoriously fragile, easily injured, and — although they recover their function in the vast majority of men who undergo this operation from a skilled, experienced surgeon — sometimes slow to heal. It can take months or even more than a year for some men to recover erectile function after surgery; some men, for reasons no one understands, do not recover this ability on their own (although there are many good treatments, including Viagra and similar drugs, to help with erectile dysfunction).
Surgeon-scientist Arthur L. Burnett, M.D., has spent much of his career working to understand how these nerves are injured. Is it possible to protect them — to give them extra armor before, during, and immediately after surgery? It’s the same basic idea as taking antibiotics before dental work — warding off infection before it starts — except in this case, the goal is to cushion and strengthen the nerves for the ordeal they’re about to endure, and the inflammation that inevitably happens afterward.
It’s the same basic idea as taking antibiotics before dental work — except in this case, the goal is to cushion and strengthen the nerves for the ordeal they’re about to endure, and the inflammation that inevitably happens afterward.
“Our goal is twofold,” says Burnett: “To improve surgical techniques, for maximal nerve preservation, and also to develop new neuroprotective treatments, to be given at the same time, for the very best chance of erectile function recovery.” What Burnett does falls into the area of neuro-urology, and he is at the forefront of this very small group of scientists and specialists worldwide. Burnett spent years studying at Hopkins in the lab of the great neuroscientist
Sol Snyder, whose pioneering work, with Burnett, led to the discovery that nitric oxide is a major chemical responsible for erection. Burnett became convinced years ago that with the right nerve-protecting agent, it might be possible to speed up the nerves’ recovery time after radical prostatectomy — or, ideally, to minimize injury altogether.
He has found a drug that looks highly promising — erythropoietin, also known as EPO. EPO is a natural product, made by the kidneys. “Its ability to improve the blood cell count in people with anemia is well known,” notes Burnett. Recently, scientists have discovered that EPO has other valuable qualities: “It can protect nerves, and facilitate their functional recovery after injury.” In laboratory experiments, Burnett and Mohamad Allaf, assistant professor of urology, found that mice given EPO showed better recovery of erectile function than those who recovered from nerve injuries (similar to those that happen in radical prostatectomy) on their own.
Based on this progress, in a recent small study, Burnett and colleagues gave erythropoietin to men who underwent radical prostatectomy. Monitoring their progress for at least a year, they found that men who received one dose of EPO before surgery recovered erections better than men who were not given the drug. Although this was a retrospective study, and cannot be considered definitive, Burnett says, “it does give us a strong basis to consider moving forward with a prospective, controlled clinical trial. Such a clinical trial is now awaiting approval.”