Growing penis tissue in the lab

Researchers have grown replacement penis tissue for rabbits from the animals' own cells. The erectile tissue was then implanted and the rabbits apparently went on to screw like rabbits, successfully reproducing. According to the scientists at Wake Forest University Baptist Medical Center, this was the "most complete replacement of functional penile erectile tissue reported to date." Someday, the technique could help human patients who require penile reconstruction due to abnormalities, cancer, or injury. It might even be used to treat extreme cases of erectile dysfunction. The research was led by tissue engineering pioneer Dr. Anthony Atala, who I posted about in 2006 for his success engineering an artificial bladder that has since helped more than two dozen patients. From the Medical Center:

The scientists first harvested smooth muscle cells and endothelial cells, the same type of cells that line blood vessels, from the animals' erectile tissue. These cells were multiplied in the laboratory. Using a two-step process, the cells were injected into a three-dimensional scaffold that provided support while the cells developed. As early as one month after implanting the scaffold in the animal's penis, organized tissue with vessel structures began to form.

The cells were injected into scaffolds on two separate days, enabling them to hold almost six times as many smooth muscle cells as in the previous studies – which the scientists believe was a key to success. During an erection, it is the relaxation of smooth muscle tissue that allows an influx of blood into the penis. The relaxation is triggered by the release of nitric oxide from endothelial cells…

Functional testing of the implanted tissue showed that vessel pressure within the erectile tissue was normal, that blood flowed smoothly through it, that the response to nitric oxide-induced relaxation was normal as early as one month after implantation, and that veins drained normally after erection.

"Laboratory-Grown Replacement of Penile Erectile Tissue"