Neuropathic ED results from damage to the nerves essential to achieving and maintaining an erection and is experienced by 79.6 percent of men who undergo radical prostatectomies. Results of the study were presented today at the annual meeting of the American Urological Association (AUA) and are published in abstract 1179 of the AUA proceedings.
"While radical prostatectomy can be a cure for early stage prostate cancer in a large percentage of patients, there are a number of risks and side effects that patients must consider when deciding on whether to have the surgery or not - one of those being the high likelihood of experiencing erectile dysfunction." said Michael Chancellor, M.D., director of neurourology at UPMC and professor of urology at the University of Pittsburgh School of Medicine. "If by using gene therapy prior to surgery, we can minimize nerve damage and preserve the patient's ability to have an erection, the patient may be less reluctant to have the potentially life-saving procedure."
In the study, researchers injected herpes simplex virus vectors that deliver neurotrophic factors, factors that facilitate the recovery of injured nerves, into the corpus cavernosum or cavernous nerve of rats at the time of cryo-injury to the cavernous nerve. The cavernous nerve is the nerve that stimulates erection; cryo-injury has similar effects on the nerve as radical prostatectomy. After injection, they found that the viral vectors transported the neurotrophic factors to the nerve. On electrical nerve stimulation, nerve-injured rats that expressed the viral vector experienced an increase in intracavernous pressure.
The researchers hope that this concept can be translated into humans, enabling gene therapy to be used as a prophylactic treatment for men undergoing radical prostatectomy.
Radical prostatectomy is used to treat the early stages of prostate cancer by surgically removing the prostate gland and surrounding tissue. The procedure has a success rate of 70 to 85 percent. A high percentage of patients experience ED after the procedure due to injury to the peripheral nerves, including the cavernous nerve, located close to the prostate gland.
In addition to studying the use of gene therapy to treat post-radical prostatectomy ED, the team from the University of Pittsburgh also is investigating the potential of using muscle derived stem cells to regenerate the peripheral nerves often damaged by radical prostatectomy.
This study is published in abstract 1256 of the AUA proceedings.