Wednesday, January 04, 2023

Bionic penis: Synthetic tissue restores erections in pigs

Agence France-Presse
January 04, 2023

Pigs in sty leaning on wall (Shutterstock)

Researchers in China have used artificial tissue to restore erectile function in pigs, a promising development for repairing penile damage in humans.

"This is an area that has received little attention, yet the related need is huge," said Xuetao Shi, an author of the study published on Wednesday in the science journal Matter.

An estimated 50 percent of men between the ages of 40 and 70 experience some form of erectile dysfunction, the researchers said, and about five percent suffer from Peyronie's disease.

Peyronie's disease, commonly caused by injury during sex, involves damage to the fibrous sheath of penile tissue known as the tunica albuginea that allows for the maintaining of an erection.

Scar tissue called plaque can cause curved or painful erections or penis shortening and may require surgical treatment.

The Chinese researchers said other tissues from the body have been used to make patches to replace a damaged tunica albuginea but those are sometimes rejected by the immune system.

Instead, the research group created an artificial tunica albuginea (ATA) that mimics the elasticity of the natural tissue with a substance called hydrogel.

Hydrogels can be natural or synthetic and are being used for a growing number of biomedical applications, including contact lenses and tissue engineering.

For the study, the researchers tested the artificial tissue on Bama miniature pigs with injuries to the tunica albuginea.

The ATA patches and a saline injection restored erectile function "similar to that of normal penile tissue," they said.

"The erection of the penis returned to normal after suturing the ATA at the injured part, and the long-term prognosis was satisfactory," they said.

Shi, a researcher at the South China University of Technology in Guangzhou, said "the results one month after the procedure showed that the ATA group achieved good, though not perfect, repair results."

The researchers said the findings "show promise for repairing penile injuries in humans" and can potentially be "extended to many other load-bearing tissues."


"Our work at this stage focuses on the repair of a single tissue in the penis," Shi said.

"The next stage will be to consider the repair of the overall penile defect or the construction of an artificial penis from a holistic perspective."

The researchers will also explore techniques to repair other tissues, including the heart and bladder, Shi said.


© 2023 AFP

An artificial tissue restores erectile function in pigs


Peer-Reviewed Publication

CELL PRESS

Bionic artificial penile Tunica albuginea 

IMAGE: BIONIC ARTIFICIAL PENILE TUNICA ALBUGINEA view more 

CREDIT: MATTER/CHAI ET AL.

Scientists have developed a synthetic tissue that repairs injuries and restores normal erectile function in a pig model, in a study publishing January 4 in the journal Matter. The findings suggest that the artificial tunica albuginea (ATA), which mimics a fibrous sheath of tissue necessary to maintain erections, shows promise for repairing penile injuries in humans.

“We largely foresaw the problems and results of the ATA construction process, but we were still surprised by the results in the animal experiments, where the penis regained normal erection immediately after the use of ATA,” said Xuetao Shi, a researcher at the South China University of Technology in Guangzhou, China, and an author of the study.

“The greatest advantage of the ATA we report is that it achieves tissue-like functions by mimicking the microstructure of natural tissues,” he added. “This design approach is not limited to the biomimetic design of tunica albuginea tissues but can be extended to many other load-bearing tissues.”

Shi said that his team’s research focus has recently turned to producing biomaterials to address issues in male reproductive health, including erectile dysfunction, infertility, and Peyronie’s disease, a connective tissue disorder thought to occur as a result of injury from sex. About half of men between the ages of 40 and 70 reportedly experience some form of erectile dysfunction, while an estimated 5% suffer from Peyronie’s disease, in which scar tissue forms in the tunica albuginea, causing pain and a range of other effects.

“We noticed that this is an area that has received little attention, yet the related need is huge,” said Shi.

While many previous studies have focused on repairing the urethra, Shi said that less research has focused on restoring erectile function. And although clinicians can treat patients with damaged tunica albuginea tissue by making patches from other tissues in the patient’s body combined with extracellular matrix, these patches come with disadvantages. Sometimes the immune system rejects them or complications occur at the donor site, and since their microstructures are different from that of natural tunica albuginea, it is difficult for these patches to replace the natural tissue perfectly.

To address this issue, Shi and colleagues developed ATA based on polyvinyl alcohol, which has a curled fiber structure similar to that of the natural tissue. As a result, the synthetic material has biomechanical properties that mimic those of tunica albuginea. The researchers performed laboratory experiments to investigate the artificial tissue’s toxicity and blood compatibility, since it is designed to remain in the body for a long time, and determined that it should not be harmful to other tissues.

Next, they tested the ATA in Bama miniature pigs with injuries to the tunica albuginea. The researchers found that patches made from the artificial tissue restored erectile function such that it was similar to that of normal penile tissue, suggesting the patch successfully replaced the natural tissues’ function. The researchers analyzed the effect of the ATA patches after one month, finding that while the artificial tissue did not restore the microstructure of surrounding natural tissue, it developed fibrosis comparable to that in normal tissue and achieved a normal erection after the penis was injected with saline.

“The results one month after the procedure showed that the ATA group achieved good, though not perfect, repair results,” said Shi.

Shi noted that in penile injuries the tunica albuginea is usually not the only tissue damaged. Surrounding nerves and the corpus cavernosum, the spongy tissue that runs through the penis’ shaft, are often damaged as well, making repairs even more difficult.

“Our work at this stage focuses on the repair of a single tissue in the penis, and the next stage will be to consider the repair of the overall penile defect or the construction of an artificial penis from a holistic perspective,” said Shi.

He added that the researchers also plan to investigate techniques to repair other tissues, including the heart and bladder.

Artificial tissue demonstrated in pig corpus spongiosum (VIDEO)

Pig corpus spongiosum is injected with normal saline to erect the penis, and the shape of the penis after erection is observed.

This work was supported by the National Key Research and Development Program of China, National Natural Science Foundation of China, Key Research and Development Program of Guangzhou, Open Funding of Guangdong Provincial Key Laboratory of Biomedical Engineering, NERC, Science and Technology Program of Guangdong Province, Guangdong Basic and Applied Basic Research Foundation Outstanding Youth Project, Science and Technology Program of Guangzhou, Hong Kong ITC, and Hong Kong Research Grant Council.

Matter, Chai et al.: “Bionic artificial penile Tunica albuginea” https://cell.com/matter/fulltext/S2590-2385(22)00663-4

Matter (@Matter_CP), published by Cell Press, is a new journal for multi-disciplinary, transformative materials sciences research. Papers explore scientific advancements across the spectrum of materials development—from fundamentals to application, from nano to macro. Visit https://www.cell.com/matterTo receive Cell Press media alerts, please contact press@cell.com.


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