An experimental nerve-growing drug could revolutionize the sex lives of prostate cancer patients, scientists say.
Thousands of men diagnosed with the disease need drastic treatment to remove the organ, which is located in the pelvis and is about the size of a ping-pong ball. But it can damage nerves that control blood flow to the penis, preventing patients from getting an erection at all – even when using Viagra.
Now researchers think hope may finally be on the horizon in the form of a drug that will enable impotent patients to regain erections.
A study in rats that received similar nerve damage found that an overactive gene slowed the body’s ability to heal damaged nerves.
But a spray-on drug that blocked the gene helped speed it back up in the rodents and restore their ability to have erections, according to the team of experts in New York.
The study in rats now suggests that the drugs can dramatically improve recovery and even return men’s sexual function to normal. However, it has not yet been tested in humans.
Many men who need drastic treatment to remove their prostate, which is located in the pelvis and is about the size of a ping-pong ball (highlighted in yellow), have lifelong problems (stock image)
These microscope images show how damaged nerves regrow more successfully when treated with gene therapy (right) compared to nerves that regrow naturally (left).
Researchers behind the discovery say 60 percent of men who undergo prostate removal surgery still have erectile dysfunction 18 months later.
And less than one in three can have erections good enough for sex five years later.
Nerve graft surgery can improve this, but it is a hit and miss procedure, and it can take years for nerves to regrow naturally or not at all.
Prostate cancer is the most common form of the disease in British men, accounting for about one in four cancers – about 50,000 per year and 250,000 per year in the US.
“Despite the so-called nerve-sparing procedures, the surgery can damage the cavernous nerves that 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 around and disrupting other parts of the body.
Nerves are fragile and pressing, 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 nerves on its own, but Albert Einstein’s researchers found that a particular gene called FL2 slowed this down.
FL2 stopped skin cells trying to reach the damaged nerves to rebuild them.
Dr. Davies and colleagues developed a drug that could block the action of FL2 and found that it accelerated the nerve healing process.
It was administered with siRNA – ‘small interfering RNA molecules’ that release genetic material that interferes with the body’s ability to make FL2.
Prostate cancer is the most common form of the disease in British men, accounting for about one in four cancers – about 50,000 per year
Three weeks after receiving the anti-FL2 drug and siRNA therapy in a gel sprayed on the nerves, 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 in their penises again.
Even rats whose nerves were completely severed managed to partially regrow them in seven out of eight cases.
In humans, severed nerves recover much less, and if they do, it can take years.
Dr. David Sharp, the co-leader of the study, said: “Erectile dysfunction after radical prostatectomy has a profound 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 every year.”
The researchers also found that taking the drug would make it more likely that taking pills like Viagra would work, as it increased levels of a chemical essential for getting an erection.
Nitric oxide, which causes the muscles of the penis to relax and allow blood to flow in, was found in greater amounts in rats treated with siRNA.
“This is important because drugs like Viagra don’t work if there isn’t nitric oxide to get things going,” said Dr. Sharp.
“But if we can restore even some of the nitric oxide in these nerves, Viagra and other erectile dysfunction drugs can exert their effects.”
The study is published in the journal JCI Insight.