Protein could heal erectile dysfunction after cancer surgery

After men have surgery to remove a cancerous prostate gland, up to 80 percent of them will lose the ability to have an erection because of damage to a critical nerve that runs along the prostate. New research from Northwestern University Feinberg School of Medicine shows the damaged nerve can be regenerated more quickly with a protein called sonic hedgehog delivered via a nanofiber gel.
The study, done with rats, showed the protein regenerated the damaged nerve twice as fast as it would have regenerated on its own. Speeding up the nerve healing is essential in order to prevent cell death in the penis and to preserve erectile function.
"This discovery about sonic hedgehog could be applicable not only to erectile dysfunction after prostate surgery but also when the cavernous nerve is damaged by diabetes, which also causes erectile dysfunction," said principal investigator Carol Podlasek, assistant professor of urology at Feinberg and a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
The whimsically named sonic hedgehog, with a wink to the popular video game character, is a vital building block in the body that promotes nerve regeneration and directs the activity of many other proteins in the body.
"There is a tremendous need for a therapy to treat erectile dysfunction caused by cavernous nerve damage," Podlasek said. Men's quality of life after prostate cancer surgery is of greater concern, she noted, because men are being diagnosed at a younger age and live longer due to improved cancer therapies.
"The biggest concern for many men before they undergo surgery for prostate cancer is quality of life after surgery" Podlasek said. "It not only affects the men undergoing surgery but also their partners."
A recent survey of patients undergoing prostate cancer treatment showed that 45 percent of patients were most concerned with quality of life after surgery, 29 percent with extending their life and 13 percent with delaying disease progression.
"So for patients with prostate cancer, being able to have an erection and lead a normal life after treatment is very important," she noted.
Nonsurgical treatments for erectile dysfunction are only effective in a minority of patients with cavernous nerve damage, she noted.
The new study findings may also apply to any damaged peripheral nerve, such as the sciatic nerve or facial nerve, that needs this protein to maintain its structure, Podlasek said.
Podlasek presented her study findings at the recent American Urological Association 2010 Annual Meeting.
When a man's cancerous prostate gland is removed, the fragile cavernous nerve is often damaged when it is crushed or pulled during surgery. Once the nerve is damaged, smooth muscle cells quickly begin to die in the penis. The consequent scarring prevents the smooth muscle from relaxing and allowing blood to flow into its tissue to become erect.
"Once the smooth muscle starts to die off, you don't get an erection or you get less of an erection," Podlasek said. "The muscle damage is irreversible, so it's essential to heal the damaged nerve as quickly as possible."
Her goal is to regenerate the nerve more quickly to reduce the damage downstream in the penis. "When the nerve is functional, you get normal erectile function," she said. "It's two pieces to a puzzle."
For the current study, Podlasek combined sonic hedgehog with a nanofiber gel designed by study coauthor Samuel I. Stupp, the Board of Trustees Professor of Chemistry, Materials Science and Engineering, and Medicine at Northwestern. The gel traps the protein as it self-assembles into linear nanofibers, which resemble slender threads made out of gel. Podlasek applied the nanofibers to crushed cavernous nerves in rats. When she examined the nerves six weeks later, they had regenerated twice as fast as they would have on their own.
In previous research, Podlasek saw a 63 percent decrease in smooth muscle cell death in the penis when sonic hedgehog was restored to injured cavernous nerves. Also in previous research, she found that decreasing sonic hedgehog in the penis caused smooth muscle cells to die.

Dont’s Use Sexual Dysfunction Products With Undeclared Ingredients

The Department of Health strongly urged members of the public not to consume products for managing male impotence from unknown sources following notification from the Hospital Authority of two patients seriously affected by this kind of products found to have contained undeclared ingredients.
A DH spokesman said the affected men, aged 76 and 87 respectively, were found collapsed in late May. Both patients once required intensive care in Mainland China and Hong Kong respectively. They are now under treatment in public hospitals. One of them was still in serious condition and the other in stable condition. Their urine specimen found the presence of undeclared drug ingredients glibenclamide and sildenafil.
Investigation showed that both of them had taken a kind of brick red rhomboid tablets. Laboratory tests on the tablets found at their homes were confirmed to have contained glibenclamide and sildenafil.
Further enquiries revealed that the 76-year-old man had also taken an unnamed blue/white capsule while the 87-year-old had taken an unlabelled blue rhomboid drug. Both of these drugs were found to have contained sildenafil.
In the past two weeks, DH received notification of two other similar cases involving patients taking brown rhomboid tablets. They claimed that the drug that they had taken named "Jiu Bian Wang"(???).
The spokesman said that "Jiu Bian Wang"was not a registered pharmaceutical product in Hong Kong. DH’s earlier laboratory tests on "Jiu Bian Wang"revealed the presence of sildenafil and a high dosage of glibenclamide. DH’s further investigation into these cases is on-going.
Today’s notification brings the number of cases related to unregistered virility products to a total of 58, affecting 56 men aged between 39 and 87. Among them, two patients passed away.
The spokesman said that glibenclamide is a diabetic drug. It could cause nausea and gastro-intestinal upset. Improper use may cause a significant fall in blood sugar level with serious health consequence and even death
The side effects of sildenafil include low blood pressure, headache, vomiting, dizziness, and transient vision disturbances. It may interact with nitrates found in some prescription drugs (such as nitroglycerin) and may lower blood pressure of patients to dangerous levels. Improper use of sildenafil may pose serious health risks, especially for patients with heart problems.
Under the Pharmacy and Poisons Ordinance of Hong Kong, products containing sildenafil or glibenclamide must be registered before sale and can only be sold on a doctor’s prescription and under supervision of a pharmacist.
The spokesman urged the public not to consume virility products of unknown or unclear sources, because the efficacy, safety and quality of such could not be assured, the spokesman said.
"Members of the public and the trade who have in their possession similar products are urged to stop consuming or trading them immediately," he said.
They should destroy and dispose of the products or submit them to the Department’s Pharmaceutical Service at 3/F, Public Health Laboratory Centre, 382 Nam Cheong Street, Kowloon during office hours.
"People who have problems of sexual dysfunction should consult medical professionals for appropriate advice or medication," the spokesman said.