Researchers have shown that artificial tissue can effectively restore erectile function in pigs with penile injuries. In between ages of 40 and 70, around half of all men with penises will suffer from erectile dysfunction. Scar tissue from previous traumas causes discomfort and dysfunction in some people with Peyronie’s disease.
The penis is often repaired by transplanting healthy tissue from another section of the patient’s body. However, human immune systems are quite adept at rejecting foreign biological components, and even effective transplants may result in complications like penis shrinking due to variations between tissue types.
Muyuan Chai and his colleagues at the South China University of Technology have resorted to synthetic tissues as a possible alternative.
Mammalian erectile tissues are supported by a network of wavy collagen fibers (with a little amount of elastin) that are stacked parallel to each other, forming a scaffold termed tunica albuginea (TA). These threads straighten out to make more space as the sponge-like tissues expand with blood, but yet keep everything together.
When the TA fibers grow to their maximum length, they stretch and provide stiffness, functioning like a hydrostatic skeleton to regulate and restrict shape change and to resist external deformation.
Scientists created a synthetic analogue to these fibers and tested out various compositions using a balloon model. Researchers discovered that the same pattern of expansion and stretch as TA was achieved by expanding isotropic polyvinyl alcohol gel and introducing crosslinks to maintain the resultant fibers in parallel alignment. This mimics the soft-to-firm transition observed in erectile tissue.
Synthetic Tunica Albuginea was what Chai and his colleagues dubbed their bionic invention (ATA). It can stretch and relax in short, rapid bursts without becoming tired or losing its toughness, and it can endure needle punctures while suturing. They used pigs with TA damages to test the synthetic tissue.
Though ATA was unable to entirely reconstruct the complicated organization of natural tissue since it could not substitute the functionality of the other tissues also engaged, such as blood vessels, it was nonetheless able to reestablish proper erectile function in the bulls following a saline injection.