SAN FRANCISCO, May 11 – Researchers from the University of Pittsburgh will present results of three studies that show that gene therapy and injections of muscle-derived cells may be effective treatments for post-prostatectomy erectile dysfunction (ED). Almost 80 percent of men who undergo radical prostatectomies experience ED due to damage to the nerves essential to achieving and maintaining an erection. Results of the studies were presented today at the annual meeting of the American Urological Association (AUA) in San Francisco.
"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 – one of those being the high likelihood of experiencing erectile dysfunction," said Michael Chancellor, M.D., senior author of all three studies and professor of urology at the University of Pittsburgh School of Medicine. "In our lab, we are seeing that by two treatments – one involving the injection of muscle-derived cells, the other involving the delivery of neurotrophic factors via gene therapy – we can minimize nerve damage and facilitate nerve recovery, preserving the patient's ability to have an erection. As a result, the patient may be less reluctant to have the potentially life-saving procedure."
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.
Glial Cell-Derived Neurotrophic Factor (GDNF) Improves Erectile Dysfunction in a Model of Post-Radical Prostatecomy Erectile Dysfunction – Abstract 1421
In this study, presented by Jang Hwan Kim, Ph.D., researchers injected herpes simplex virus vectors that deliver glial cell derived neurotrophic factors (GDNF) – 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 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 GDNF to the nerve. On electrical nerve stimulation, nerve-injured rats that expressed the viral vector experienced an increase in intracavernous pressure.
Injection of Skeletal Muscle-Derived Cells Into the Penis Improves Erectile Dysfunction – Abstract 1414
Muscle-derived cells (MDC) are cells which can be obtained through muscle biopsy, cloned and reinjected into the body. MDC possess a high level of plasticity in response to environmental cues and are able to differentiate into different types of tissue. In this study, the University of Pittsburgh researchers injected MDC into the penis of rats with injury to the cavernous nerve. MDC-injected models showed an increase in intracavernous pressure indicating the regeneration of the injured nerve. Results will be presented by Yong-Tae Kim, Ph.D.
Muscle-Derived Cells Improve Erectile Dysfunction in a Model of Post-Radical Prostatectomy Erectile Dysfunction – Abstract 1422
Brandon Minnery, Ph.D., will present results of a similar study. In this study, researchers injected MDC into animal models with cavernous nerve injury. In addition to measuring intracavernous pressure, they measured the electric responses of the nerve or the compound action potential (CAP). Injured models treated with MDC had a higher CAP and intracavernous pressure than injured models not treated with MDC, indicating that MDC may be able to accelerate the restoration of erectile function following radical prostatectomy.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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