An experimental drug for nerve growth could revolutionize the sex lives of prostate cancer patients, scientists say.
Thousands of men diagnosed with the disease require drastic treatment to remove the organ, which is located in the pelvis and is the size of a ping pong ball. But it can damage the nerves that control the blood supply to the penis, leaving patients completely unable to get an erection – even using Viagra.
Now, researchers believe that hope could finally be on the horizon in the form of a drug that allows helpless patients to get erections again.
A study in rats with similar nerve damage found that an overactive gene slows the body’s ability to heal damaged nerves.
But a spray drug that blocked the gene helped speed it up in rodents and restored their ability to get erections, according to the New York team of experts.
The study in rats now suggests that the drugs could drastically improve recovery and even restore men’s sexual function to normal. However, it has not yet been tested on humans.
Many men who need drastic treatment to remove their prostate, which is in the pelvis and is the size of a ping pong ball (highlighted in yellow), have problems throughout their lives (stock image)
These microscopic images show how damaged nerves grow back more successfully when treated with gene therapy (right) compared to those that are allowed to regress naturally (left).
The researchers behind the discovery say that 60 percent of men who have a prostate removal operation still have erectile dysfunction 18 months later.
And less than one in three can get erections good enough for sex at five years old.
Nerve graft surgery can improve this, but it is a procedure to hit and miss, and letting the nerves grow naturally can take years or not happen at all.
Prostate cancer is the most common form of the disease among British men, accounting for about one in four cancers – about 50,000 a year and about 250,000 a year in the United States.
“Despite so-called nerve-saving procedures, surgery can damage the cavernous nerves, which control erectile function by regulating blood flow to the penis,” said Dr. Kelvin Davies of the Albert Einstein College of Medicine in New York.
The prostate is a small organ surrounded by other tissues, so surgery to remove it inevitably involves pushing and disrupting other parts of the body.
Nerves are fragile and pressing on them, pulling or damaging them with tools such as scalpels can affect how well they work. This can lead to numbness or muscle weakness.
The body can heal the nerves itself, but researchers Albert Einstein found that a certain gene, called FL2, slowed this down.
FL2 stopped skin cells trying to reach damaged nerves to help rebuild them.
Dr. Davies and colleagues have developed a drug that could block FL2 from working and have found that it speeds up the healing process of nerves.
It was administered using siRNA – “small interfering RNA molecules” that deliver genetic material that disrupts the body’s ability to produce FL2.
Prostate cancer is the most common form of the disease among British men, accounting for about one in four cases of cancer – about 50,000 a year.
Three weeks after administration of the anti-FL2 drug, siRNA therapy in a gel that was sprayed on the nerves, the rats had “significantly better erectile function” compared to untreated rats.
And after a month of treatment, the researchers found that the treated rats had normal blood pressure levels in their penises.
Even rats whose nerves were completely cut off were able to partially regenerate in seven out of eight cases.
In humans, severed nerves are much less likely to recover and, when they do, can last for years.
Dr. David Sharp, co-leader of the research, said: “Erectile dysfunction after radical prostatectomy has a major impact on the lives of many patients and their partners.
Because rats are reliable animal models in urological research, our drug offers real hope of normal sexual function for the tens of thousands of men who undergo this surgery each year.
The researchers also found that using the drug could make taking pills like Viagra more likely to work because it increases the level of the chemical, which is vital to getting an erection.
Nitric oxide, which relaxes the muscles of the penis and allows blood to flow, has been found in greater amounts in siRNA-treated rats.
“This is important because drugs like Viagra don’t work if there is no nitric oxide to start things off,” said Dr. Sharp.
“But if we can restore even some of the nitric oxide in these nerves, Viagra and other erectile dysfunction drugs could have their effects.”
The study was published in the journal JCI Insight.