• Posted February 9, 2024

Use It or Lose It? Mouse Study Reveals Key to Healthy Erections

Is 'practice makes perfect' true for the male erection, too?

That's the suggestion from a Swedish study involving amorous male mice. It found that getting erections regularly was important to the rodents' overall erectile function.

The key seemed to lie in connective tissue cells called fibroblasts.

These cells have long been known to populate penile tissue, but their role has remained unclear, explained researchers from the Karolinska Institute in Stockholm.

“Fibroblasts are the most abundant cells in the penis of both mice and humans, but they have been neglected in research,” said study lead author Eduardo Guimaraes, a researcher at the department of cell and molecular biology at Karolinska.

“Now we can show, using a very precise method called optogenetics, that they have a very important role in regulating blood flow in the penis, which is what makes the penis erect," he said in an institute news release.

The findings were published Feb. 8 in the journal Science.

Of course, many studies conducted in mice don't translate to humans. But the Swedish team said that -- size aside -- the penises of mice and men aren't dissimilar.

“The basic mechanisms of erection are very similar in all mammals regarding anatomy, cell structure and so on,” principal investigator Christian Göritz explained.

“However, there is one difference between humans and most mammals -- they have a bone in their penis," added Göritz, who is a senior researcher at Karolinska's department of cell and molecular biology. "This means that effective blood flow regulation is probably even more important for human reproduction.”

In their investigation, Göritz and Guimaraes discovered that fibroblasts help spur erections as they take up the neurotransmitter noradrenaline, which in turn opens up penile blood vessels.

And the more often a mouse got erect, the more erection-inducing fibroblasts were found within his penile tissue.

“It's not so strange really. If you exert yourself a lot, your body adapts. If you run regularly, it will eventually become easier to breathe while running,” Göritz explained.

So, "an increased frequency of erections leads to more fibroblasts that enable erection," he said.

The opposite also appeared to be true: "A decreased frequency results in fewer of these cells," Göritz said.

There was a bit of bad news for aging males, however: Older mice tended to have fewer fibroblasts in their penises, and less robust blood flow.

Could the same be true for older human males, who are often confronted with erection issues?

The Swedish team believe it's possible, and that regular erection "training" might help prevent it, much like gym workouts help maintain muscle strength.

That's yet to be proven, however.

"This is not something we have shown in our study, so it is a bit speculative, but a reasonable interpretation is that it gets easier if you have regular erections,” Göritz said.

The researchers also hope their findings might encourage research into better treatments for erectile dysfunction, which is estimated to affect between between 5% and 20% of all men.

More information

There's more on erectile dysfunction at the National Institute of Diabetes and Digestive and Kidney Diseases.

SOURCE: Karolinska Institute, news release, Feb. 8, 2024