Synthetic Tissue Can Repair Penis Injury in Pigs, Study Shows

An artificial, hydrogel-based tissue has been developed to repair penile tissue damage and restore erectile function in pigs. Early results suggest the synthetic tissue may provide hope for men struggling with similar penis injuries, though that would be years down the line.

Researchers at South China University of Technology in Guangzhou created an artificial synthetic tissue to successfully repair penile fractures, specifically, injuries to the tunica albuginea. They used the synthetic tissue in a study of Bama miniature pigs with penile injuries and found the tissue could repair damage to the tunica albuginea and actually restore erectile function.

Their findings were published in the journal Matter.

Penis injury

In order to understand the study, a brief lesson in erections might be helpful. Erections have nothing to do with skeletal bones of any kind—the human penis doesn't have bones—but much to do with blood flow.

During an erection, blood flows to the penis and fills two columns of spongy tissue called the corpora cavernosa, which run along the shaft of the penis. If an erect penis is forcibly bent during sexual intercourse, or any other scenario, the resulting trauma can rupture the tunica albuginea, the layer that surrounds the outside of the corpora cavernosa.

This trauma can cause microtears that lead to damage over time or a more serious complication called a penis fracture.

While rare, penile fractures typically occur during intercourse or aggressive masturbation, according to Barbara Chubak, M.D., an assistant professor of urology at the Icahn School of Medicine at Mount Sinai in New York City.

"You can't fracture your penis unless it is erect," Chubak said. "So this is an injury that typically occurs in the context of sexual activity."

The risk of injury increases as the penis becomes erect, she said.

"A flaccid penis can be safely manipulated and moved in any number of directions," she said. "But once it gets hard, that's when an injury can happen, by moving the wrong way."

Pig penile problems

What's interesting about the artificial substance the scientists in China developed is that it is capable of mimicking the natural function of the tunica albuginea. The researchers sutured the synthetic tissue into parts of the tunica albuginea that had been injured to repair the area.

They found the repairs resulted in a return of erectile function in the miniature pigs with penile fractures.

"The mammalian tunica albuginea [TA] is characterized by a double-layer orthogonal structure composed of stacked parallel wavy collagen fibers," the study authors wrote. "During an erection, these fibers undergo sequential straightening and stretching to mediate the soft-to-firm transition. Inspired by the delicate strain-adaptive structure of natural TA, we propose an artificial TA (ATA) composed of a strain-stiffening hydrogel consisting of aligned yet crimped fibers. This delicate structure is produced via the stretching of an isotropic polyvinyl alcohol gel followed by covalent cross-linking."

The artificial tunica albuginea mimics key properties seen in a natural tunica albuginea including "rapid strain stiffening over small intervals of deformation, excellent fatigue resistance to sustain cyclic bursts, and high toughness to withstand pointwise acupuncture during suturing," according to the study.

In other words, the study highlights the artificial tissue's ability to repair injuries and restore normal erectile function in pigs with damaged tunica albuginea, according to the authors.

Don't ignore a penis fracture

Signs of a penis fracture, according to Mayo Clinic, include:

• Immediate penile pain
• Rapid loss of an erection
• Swelling in the penile shaft
• Discoloration of the penile shaft due to bleeding underneath the skin

Without immediate medical attention, the injury can cause penis disfiguration and permanent erectile dysfunction (ED).

"The most important thing is to get it checked out quickly," Chubak said. "Urology doesn't have a lot of surgical emergencies, but this is considered one of them."

She said patients who seek treatment immediately following a penile fracture are more likely to have less significant ED due to the injury, if any at all, than those who seek treatment too late or not at all.

"If you let the embarrassment or inconvenience of going prevent you from getting checked out by the doctor promptly, there's a higher probability of lasting erectile dysfunction," she added.

"Having it assessed rapidly is important," said Cara Cimmino, M.D., assistant professor of urology at the Emory University School of Medicine in Atlanta. "When penile fractures happen, you want to take them back as soon as possible to the operating room when you identify it. If you identify it two, three days later, studies have shown there's not really a benefit to going back to the operating room; it's more of an immediate thing."

Conclusions

"Our study demonstrates that [artificial tunica albuginea] has great promise for penile injury repair," the study authors stated.

Again, it will be years before the use of this synthetic tissue is potentially applicable to human subjects.

Future research may look at the ability to repair other vital organs, such as the heart or bladder, using similar artificial tissues, said one of the study's authors, Xuetao Shi, of South China University of Technology, in a press release.