US researchers have successfully engineered fully functional penises for rabbits. The technique may someday be useful for people, it is hoped.
In a study published in the Proceedings of the National Academy of Sciences, the team said, "Various reconstructive procedures have been attempted to restore a cosmetically acceptable phallus that would allow normal reproductive, sexual, and urinary function in patients requiring penile reconstruction. However, these procedures are limited by a shortage of native penile tissue. We previously demonstrated that a short segment of the penile corporal body can be replaced using naturally derived collagen matrices with autologous cells. In the current study, we examined the feasibility of engineering the entire pendular penile corporal bodies in a rabbit model. Neocorpora were engineered from cavernosal collagen matrices seeded with autologous cells using a multistep static/dynamic procedure, and these were implanted to replace the excised corpora. The bioengineered corpora demonstrated structural and functional parameters similar to native tissue and male rabbits receiving the bilateral implants were able to successfully impregnate females. This study demonstrates that neocorpora can be engineered for total pendular penile corporal body replacement. This technology has considerable potential for patients requiring penile reconstruction."
The new penises responded normally to electrical and chemical stimuli, and — more importantly — to biological imperative. When given the chance to have sex, eight were able to ejaculate, and four became fathers.
Indeed, they became more aroused than the rest. "Most control rabbits did not attempt copulation after introduction to their female partners," said the researchers. "All rabbits with bioengineered neocorpora attempted copulation within one minute of introduction."
Anthony Atala, director of Wake Forest University's Institute of Regenerative Medicine, who led the team, is best known for developing a technique in which cells are taken from an organ and sprayed onto a frame made of collagen, the primary structural protein in animal tissue. The structure is then bathed with growth-stimulating compounds and kept in an oven that duplicates the body's temperature and chemical composition, Brandon Keim wrote on the Wired.
Atala's group has already implanted lab-grown bladders, grown from the patients' own tissue, in seven men.