Tissue engineers grow penis in the lab

Tissue engineers grow penis in the lab
19:00 11 September 2002
Exclusive from New Scientist Print Edition.
Sylvia Pagán Westphal, Boston

In a remarkable feat of tissue engineering, major parts of the penises of several rabbits have been replaced with segments grown in a lab from their own cells. The animals were able to use the reconstructed organs to mate.

The next step is to try to recreate the entire organ from scratch. The technique could make it possible to reconstruct the penises of men who have suffered injuries or those of children born with genital abnormalities.

"If you have a child born with ambiguous genitalia, it’s a life-changing event," says Anthony Atala of Harvard Medical School, whose team carried out the work.

It could also provide an alternative to the crude methods currently used to enlarge the organ, such as injecting fat cells or cutting the penis’s suspensory ligament and "pulling out" more of the internal part. Instead, a patient would have penile cells removed by a doctor and, a few weeks later, the organ or parts of it grown using the cells could be surgically implanted.
More complex

While the particular nature of the research is likely to attract much attention, it is also one of the most impressive attempts at tissue and organ engineering to date. "The penis is more complex than any of the organs we have engineered so far," says Atala, whose team has already created fully functional bladders that may soon be implanted in people.

The penis is more difficult to recreate because it has more functions and, unlike the bladder, is also a solid organ.

It consists of three main cylinders, encased in an outer layer of connective tissue, skin, blood vessels and nerves. The two biggest cylinders, made of spongy material that swells during an erection, are the corpora cavernosa. The third tube encases the urethra.

Of those structures, the corpus cavernosum is the most challenging to replace or reconstruct. It contains specialised muscle and endothelial cells - the cells that line blood vessels - and its structure is hard to mimic. Yet this is the part that Atala has been able to grow.
Half pressure

His team first extracted three-dimensional scaffolds of collagen from the erectile tissue of rabbits. They also took samples of the specialised muscle and endothelial cells from penises of each of the rabbits destined to receive the implants.

These cells were grown separately at first, and then added to the collagen matrix in the appropriate proportions. After a few days more growth, the result resembled real erectile tissue.

Next, Atala removed the corpora cavernosa from almost the entire length of the exterior part of the penises of 18 rabbits, leaving the nerves and urethra intact. He then replaced them with the engineered erectile tissues. Because the tissues were grown from the rabbits’ own cells, there was no problem with immune rejection.

Once they had recovered from the surgery, the rabbits attempted to have sex within 30 seconds of being put in a cage with a female. "They were able to copulate, penetrate and produce sperm," Atala told New Scientist.

More detailed studies revealed that the penises generated about half of the normal pressure of an erect penis. "It’s analogous to the penis of a 60-year-old man, versus that of a 30-year-old," says Atala. Details of the work will be published in the October issue of The Journal of Urology.

http://www.news cientist.com/ar … le.ns?id=dn2781

Hmmm, I wasn’t born with 6.5 in girth. Once they perfect it and can get them fully hard…I wonder if they can help me? A shortcut perhaps?

For now, I’ll stick with the tried and true methods of taking it slow and easy, doing what I’ve learned here.

This is a update to the article posted above.

Click to PrintTissue engineers grow penis - with feeling
17:00 29 April 2003
NewScientist.com news service
Celeste Biever

Tissue engineers who recently demonstrated penis replacement in animals have now added a vital missing component - nerve cells.

"The nerve cells are very important - they are responsible for all the sensory function," says Anthony Atala, at Boston Children’s Hospital. "In order to do complete [penile] replacements we need to make sure all of the parts are there, including the nerves."

In September 2002, Atala and his colleagues replaced missing chunks of penis in live rabbits with tissues grown in the lab. But the replacement penile tissues consisted only of muscle and endothelial cells, which were inserted alongside intact nerve cells. Their new work is the first time that penile nerve tissue has been regenerated.

"This is exciting and extends their work logically in several directions," says reconstructive surgeon Hunter Wessells of the University of Washington School of Medicine in Seattle.

The regeneration of nerves is an important step towards one day creating engineered replacement penile tissue for men who have lost parts of the penis following prostate cancer surgery or an accident, or to enhance the genitals of children born with abnormalities.

Mimicking nature
The secret to regrowing the nerve cells is mimicking nature, explains Atala. His team began by building millimetre-wide collagen channels. These replicate the sheaths that, like the insulation around a bundle of electrical wires, surround nerves in the body.

The team then cut away the nerve cells in the penises of live rats and sewed the collagen channels to the severed nerve stumps. After three months, functional nerve cells one centimetre long had grown inside the channels.

The physical support from the collagen appeared to be all that was needed to coax the nerve cells into growing. The collagen-supported cells grew just as well as nerves that were grafted on in experiments conducted for comparison.

The next challenge will be encouraging them to grow to even greater lengths without losing their functionality, says Atala.

Splice and connect
In the next few years, Wessels envisions using the technique to solve the "challenging problem" of returning feeling, or just the ability to have an erection, to men with intact penises who have lost nerve function.

Growing nerves in situ could replace the technique of nerve grafts, which requires the removal of valuable tissue from another part of the body. Nerve grafts were first used in penises in 2000.

But he says it will be closer to 10 years before a fully-functional tissue engineered penis is grown in the lab and attached to a man or child. That will require overcoming the challenge of splicing and connecting nerves in the lab-grown penis to the central nervous system, he warns.

The new research was presented by Atala at the annual meeting of the American Urological Association in Chicago on Tuesday.

http://www.news cientist.com/ar … le.ns?id=dn3672

I wish this technology was not ten years away. This article was dated 2003, so it’s only six years away:)

Hmmm :-k We are growing our tissue cells right here at Thunders except that:

No cells need to be removed except the ones that shed naturally.
It does not require trips to a lab and possibly letting some dude handle your penis.
Without the risk of surgery and/or post surgery complications.
Without having to explain yourself to family and friends.
Without making you 35-40 G’s (who knows what?) or more poorer.

I just wish my cells would grow faster.:)

You would do the same thing if a doctor had “removed the corpora cavernosa from almost the entire length” of you penis, then replaced it with “engineered erectile tissues”.

I really can’t imagine that the rabbits volunteered for this experiment…

GM