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The construction and implantation of functional penile corpora cavernosa in a rabbit model, resulting in successful copulation and impregnation, has been reported by Anthony Atala and colleagues from the Wake Forest Institute for Regenerative Medicine. “Currently there is no substitute for penile erectile tissue and few options for patients,” notes Atala.

The researchers isolated rabbit smooth muscle and endothelial cells from corporal biopsies and seeded them onto structural matrices made from decellularized donor corpora cavernosa using a multistep procedure to optimize cell density. These seeded matrices were used to replace the entire length of both pendular penile corpora in 12 healthy male rabbits.

Graft structure and function and rabbit behavior were evaluated at 1, 3 and 6 months after surgery. All the experimental rabbits developed and maintained normal intracorporal pressures, allowing them to attain erection. When placed with female rabbits, all 12 males attempted copulation. In 8 of the 12 cases, vaginal swabs taken from the females contained sperm, and 4 females were impregnated.

The researchers state that this is the most complete functional replacement of penile tissue reported to date. Anatomical reconstruction of the penis is often limited by a shortage of native penile tissue, and reconstruction of functional erectile tissue has been particularly challenging. This research demonstrates that functional penile tissue can be successfully engineered. “There is nothing more devastating for a surgeon than to be in the operating room and to have no tissue to give to a patient who needs it,” says Atala. “Our hope is that this technique can one day be used to help patients with congenital abnormalities, penile cancer, traumatic injury and some types of erectile dysfunction.”