Scientists say an experimental nerve-growing drug could revolutionize the sex lives of prostate cancer sufferers.
Thousands of men diagnosed with the disease need drastic treatment to remove the organ, which sits in the pelvis, about the size of a table tennis ball. But it can damage nerves that control the blood supply to the penis, so patients can not get an erection at all – not even with Viagra.
Now, researchers believe the hope may finally be on the horizon in the form of a remedy that enables impotent patients to get erections again.
In a study on rats that suffered similar nerve damage, an overactive gene was found to slow down the body’s ability to heal damaged nerves.
But a spray that blocked the gene helped speed it up in the rodents and bring back their ability to get erections, according to the team of experts in New York.
The rat study now suggests that the drugs could drastically improve recovery and even return 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 sits in the pelvis and is about the size of a table tennis ball (highlighted in yellow), have lifelong problems (stock image)
These microscopic images show how damaged nerves grow more successfully when treated with gene therapy (right) compared to those that grow naturally again (left)
Researchers behind the discovery say 60 percent of men with prostate removal surgery still have erectile dysfunction 18 months later.
And less than one in three can get erections good enough for sex five years later.
Nerve transplantation can improve it, but it is a hit-and-miss process, and getting nerves to grow can take years or never happen.
Prostate cancer is the most common form of the disease among British men, accounting for about one in four cancer cases – about 50,000 a year and 250,000 a year in the US.
“Despite so-called nerve-sparing procedures, the operation can damage the cavity nerves, which control erectile function by regulating the blood supply to the penis,” said Dr. Kelvin Davies, of the Albert Einstein College of Medicine in New York, said.
The prostate is a small organ that is surrounded by other tissues, so surgery to remove it must necessarily push around and disrupt other pieces of the body.
Nerves are fragile and pushing them up, pulling them or damaging them with tools such as scalps 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 one specific gene, called FL2, slows it down.
FL2 was stopping skin cells from trying to help rebuild the damaged nerves.
Dr Davies and colleagues developed a drug that could interfere with the action of FL2 and found that it speeds up the nerve healing process.
It was administered using siRNA – ‘small interfering RNA molecules’ that deliver genetic material that disrupts the body’s ability to make FL2.
Prostate cancer is the most common form of the disease among British men, accounting for about one in four cancer cases – about 50,000 a year
Three weeks after the siRNA therapy was administered in a gel sprayed on the nerves to the anti-FL2 agent, 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.
Even rats that cut off their nerves completely were able to partially regrow it in seven out of eight cases.
Cut-off nerves are much less likely to recover in humans, and it can take years if they do.
Dr David Sharp, co-leader of the research, said: ‘Erectile dysfunction after radical prostatectomy has a huge impact on the lives of many patients and their partners.
“Because rats are reliable animal models in urological research, our drug offers real hope for normal sexual function for the tens of thousands of men who undergo this surgery each year.”
The researchers also found that using the drug is more likely that the intake of pills like Viagra will work because it increases the levels of a chemical that is essential for erection.
Nitric oxide, which relaxes the penis muscles and causes blood to flow in, has been found in larger quantities in rats treated with siRNA.
“This is important because drugs like Viagra do not work when there is no nitric oxide to kick things off,” said Dr. Sharp said.
“But if we can even recover some of the nitric oxide in these nerves, Viagra and other erectile dysfunction drugs can exert its effects.”
The study was published in the journal JCI Insight.