Penile fibroblasts are more important for erectile function than previously thought

Regular erections may be important for maintaining erectile function, according to a new mouse study published in Science by researchers from Karolinska Institutet. “We found that an increased frequency of erections leads to an increase in the number of fibroblasts that enable erection and vice versa, that a reduced frequency leads to a decrease in the number of these cells,” explains lead researcher Christian Göritz.

In this new study, researchers from Karolinska Institutet and Uppsala University in Sweden show that connective tissue cells called fibroblasts have a previously unknown and very important function in mediating erection.

“Fibroblasts are the most abundant cells in the penis of mice and humans, but they have been neglected in research,” explains Eduardo Guimaraes, researcher at the Department of Cellular and Molecular Biology at Karolinska Institutet and first author of the article .

“We can now show, through a very precise method called optogenetics, that they play a very important role in regulating blood flow in the penis, which makes the penis erect.”

The study shows that fibroblasts ensure erection by capturing the neurotransmitter norepinephrine, which causes blood vessels in the penis to widen. The effectiveness of this process depends on the number of fibroblasts.

The body adapts

The researchers were also able to show that the number of fibroblasts in the penis is affected by the frequency of erections. The more frequent they are, the more fibroblasts there are and vice versa; a lower frequency of erections reduced the number of fibroblasts.

“It’s really not that strange. If you exert a lot of effort, your body adapts. If you run regularly, it will eventually become easier to breathe while running,” explains Christian Göritz, senior researcher at the Department of Biology cellular and molecular of Karolinska. Institutet, who led the study.

As for the conclusions that can be drawn from mouse studies for humans, Christian Göritz believes that there are significant similarities here.

“The basic mechanisms of erection are very similar in all mammals with respect to anatomy, cellular structure, etc.,” he says. “However, there is one difference between humans and most mammals: They have a bone in their penis. This means that effective regulation of blood flow is probably even more important for human reproduction.”

Fewer fibroblasts with age

Older mice had fewer fibroblasts in the penis, which also resulted in decreased blood flow. The ability to have an erection also declines with age in men, which may be due in part to the decrease in the number of fibroblasts in the penis. So researchers think it might be possible to train the ability to get an erection to combat impotence in the same way that you train your strength or fitness at the gym.

“That’s not something we showed in our study, so it’s a bit speculative, but a reasonable interpretation is that it becomes easier if you have regular erections,” says Christian Göritz.

He hopes that new knowledge about the role of fibroblasts in erections may also lead to new treatments for erectile dysfunction.

Erectile dysfunction, or impotence, affects between 5 and 20% of all men, and its incidence increases with age. Erectile dysfunction often negatively affects the quality of life and physical and psychosocial health of both the patient and their family.

Common risk factors, in addition to age, are similar to those for cardiovascular disease: inactivity, obesity, hypertension, smoking, high cholesterol and metabolic syndrome.