backtop


Print 65 comment(s) - last by molgenit.. on Nov 18 at 3:08 PM


Scientists have engineered fully functional rabbit penises, replacing damaged penis spongy tissue for the first time. The penises stay erect, and ejaculate, and the rabbit proved much more sexually active than normal male rabbits.  (Source: PNAS/Wake Forest University)

Anthony Atala, M.D.  (Source: Winston-Salem Journal)
Rabbit recipients of artificially grown penises are eager to copulate with female partners

We've seen all sorts of tissue engineering examples -- from bone, to brain tissue, to nerves, to vascular tissue, and even muscles -- but a new study from the Wake Forest University’s Institute of Regenerative Medicine has surpassed all of these in pure strangeness.  The study used advanced tissue regrowth techniques to create and endow lab rabbits with fully functional replacement penises.

The research was led by the institute's director, Anthony Atala, M.D., who is most famous for devising a cell seeding technique that involves spraying cells harvested from an applicable tissue onto a collagen matrix, led the research.  Under Dr. Atala's scheme the developing tissue is bathed in a nourishing serum than keeps the tissue in a chemical environment similar to the human body, and at a similar temperature to that of the human body.  Growth factors and other beneficial compounds are seeded into the tissue beforehand, to encourage the cells to divide and populate the new tissue.

Most cells contain a wealth of information about how to grow and form their local tissue.  Once in a receptive scaffold (like the collagen), they're sometimes able to grow and form new tissues, if they're exposed to the proper chemicals and physical conditions.  By combining one or more tissue types and encouraging the growth of blood vessels, organs can be formed.

Dr. Atala's team had already regrown and implanted seven human male bladders, a significant success.  Ten years later, the patients are still showing good function.  However, the penis proved a much more elusive and complex tissue to grow.  Growing the outer skin in theory wouldn't be overly challenging, but the inner spongy tissue, called corpus cavernosa, proved to be a much stiffer challenge due to the complex mix of cell types needed.

Past artificial penises grown at Wake Forest were taken off the drawing board after failing to stay erect when implanted into rabbits with a piece of their spongy tissue removed.  After close to 18 years of failed attempts, the researchers tried a different angle, removing the entire spongy tissue (not just a segment) and using different growth factors on a complex mix of cells, including smooth muscle cells and endothelial cells -- the cells needed to form the arteries needed to bring blood to the penis's spongy tissues, allowing it to become erect.

The result was a resounding success.  Writes the research team in their paper on the accomplishment, "This technology has considerable potential for patients requiring penile construction."

The resulting penises were identical to their natural kin in response to electrical and chemical stimuli.  And the recipient rabbits proved eager to copulate, with eight of the 12 rabbits with implants achieving ejaculation and four becoming fathers.  While rabbits normally like to procreate over the long term, the recipients proved unusually randy, attempting to procreate much faster than normal male rabbits.

Describes the team, "Most control rabbits did not attempt copulation after introduction to their female partners.  All rabbits with bioengineered neocorpora attempted copulation within one minute of introduction."

The study was reportedly published in the journal Proceedings of the National Academy of Sciences (PNAS) on Monday, though a quick glance at the November 9 early edition did not show the study. 

The research proves eerily similar to the frequently on-point animated show South Park's episode "Eek a Penis", which aired last year and involved the character Mr./Mrs. Garrison having his/her penis regrown on a lab rat.  Despite the success, though, such more advanced sex change operations remain out of reach, as scientists have yet to engineer functional testicles from body tissues.  Still, for some with damaged penis tissue, this study may provide new hope.

The research team next plans to start trying to implant regrown human penis tissue.  States Dr. Atala, "We're going to be doing that experimentally at our center."



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

Donor material?
By tmouse on 11/10/2009 7:50:24 AM , Rating: 1
I guess this will bring new meaning to the term "organ donor". You will be hard pressed to find a living donor for this. "Just a little off the top doc". Some recipients of organ transplants have claimed to have phantom memories connected to the organ donor, On a genetic level the number of genes expressed in the brain that overlap with testis has been a long running joke in high throughput genetic analysis circles. Why on earth there would be work on testis regeneration is beyond me, unless you can populate them with the recipients primary germ cells you might as well just keep putting plastic balls in, unless the idea of spreading someone else's genes get you going.




RE: Donor material?
By Brandon Hill (blog) on 11/10/2009 7:51:25 AM , Rating: 2
I guess they could use the "leftovers" from circumcision after birth?


RE: Donor material?
By tmouse on 11/10/2009 8:46:21 AM , Rating: 5
Unless you are using "shakey the moyle" from Seinfeld, circumcision is the surgical removal of part or all of the prepuce (the skin sourrounding the outside)if he is cutting into the corpus cavernosa you have trouble.


RE: Donor material?
By GotDiesel on 11/10/2009 1:03:35 PM , Rating: 1
after birth ??? who does that and why ?.. i was under the impression that it was a religious practice by Jewish people ?


RE: Donor material?
By armulyman on 11/10/2009 2:27:47 PM , Rating: 3
do you not watch porn?!


RE: Donor material?
By tmouse on 11/10/2009 2:47:35 PM , Rating: 2
It's widely practiced in most US hospitals. Most thoughts were it was better from a hygiene point of view and while it's certainly not necessarily better a bit more care must be taken with uncircumcised babies to avoid bacterial growth. Some state sex is "better" if uncircumcised, there is no real evidence one way or the other, VERY few males reach sexual maturity and then get circumcised and there has not been any surveys I'm aware of. The other point is you do not miss what you never had so the sex point is moot. It's not rare today but there is no right or wrong answer either. What I have observed is on the other end of the spectrum: very elderly men often have infection problems if uncircumcised and the added embarrassment of urinating on themselves.


RE: Donor material?
By AlmostExAMD on 11/11/09, Rating: -1
RE: Donor material?
By inperfectdarkness on 11/12/09, Rating: 0
RE: Donor material?
By tmouse on 11/10/2009 8:55:06 AM , Rating: 3
I should also point out that humans, unlike rabbits and most other mammals do not have a baculum. Rabbits could mate with a somewhat defective corpus cavernosa, humans could not.


RE: Donor material?
By drmo on 11/10/2009 12:18:32 PM , Rating: 3
Rabbits do not have a baculum.


RE: Donor material?
By tmouse on 11/10/2009 2:33:18 PM , Rating: 2
I stand corrected, I've gotten antibodies from them but all of those rabbits were females. Lagomorpha is a strange order, who puts their scrotum in front of their penis?


RE: Donor material?
By MrPoletski on 11/16/2009 9:20:52 AM , Rating: 2
A professional rochambeau trader?


RE: Donor material?
By molgenit on 11/18/2009 3:08:31 PM , Rating: 2
Not being a big south park fan I had to look that up. I was aware the Japanese had a fetish involving that but having a game is a bit too weird for me. I do not think moving the jewels up a few inches would help much.


RE: Donor material?
By MrBlastman on 11/10/2009 12:36:47 PM , Rating: 3
What I'm curious is, what man in their right man is going to read the bulletin board on campus one day and see:

"Male subject needed for penile vivisection and artificial implantation study to test the viability of a re-grown proboscis and its procreative efficacy. Hot chicks will be provided!"

... and say, "Gee, that sounds swell. I get my **** operated on by hot chicks!" Hmm, in retrospect, it might just work.

Any sane person though I imagine wouldn't want their rod chopped off and a new one put on in its place. That area is a "no sharp objects allowed" zone.


RE: Donor material?
By Drag0nFire on 11/10/2009 6:58:03 PM , Rating: 2
Jokes aside, they will never test this on a healthy subject - to do so would be unethical. However, the prevalence of congenitally malformed genitals is higher than one might expect. If severe enough, these individuals have little recourse. This treatment would probably be tried in this population.

Curious about what age group they will work with though.


RE: Donor material?
By rudy on 11/10/2009 8:43:16 PM , Rating: 2
Also sex chance candidates will be interested.


RE: Donor material?
By ViroMan on 11/11/2009 12:25:46 AM , Rating: 2
And anyone who wants a 2 foot long probe. :)


RE: Donor material?
By drmo on 11/10/2009 9:40:05 AM , Rating: 2
"Why on earth there would be work on testis regeneration is beyond me, unless you can populate them with the recipients primary germ cells you might as well just keep putting plastic balls in, unless the idea of spreading someone else's genes get you going. "

First, the testes also contain hormonal cells, so those who have lost their testes (or those undergoing female-male sex changes) would not have to take constant hormonal treatments. Second, it may be possible to use adult stem cells (or cloned embryonic stem cells) to produce sperm, so one could use one's own cells to grow the seminiferous tubules/sperm. I think the first reason is probably more significant.


RE: Donor material?
By tmouse on 11/10/2009 3:00:28 PM , Rating: 2
I'll agree to your first point although artificial testis is not necessary for that, Leydig cells could be grown any ware even within the body (it's the sensitivity of the primary spermatogonia that requires a lower temperature). As for the second point about germ cells you couldn't be farther off base. You cannot make primary germ cells from adult stem cells, germ line segregation happens very early in development , add to that the complications of reestablishing the environmental conditions to reestablish genomic imprinting and I highly doubt it would ever be possible. You may be ok with a muscle that is only 75-100% similar to a real muscle cell a primary germ cell that has to undergo meiosis had better be 100% or you will get a 100% failure in the resulting sperm.


RE: Donor material?
By drmo on 11/10/2009 5:26:56 PM , Rating: 2
Whereas it is difficult to make germ cells from adult cells, it appears it is not impossible. http://www.nature.com/labinvest/journal/v86/n7/ful...

I agree that you could possibly put Leydig cells many places in the body, and they could work fine.


RE: Donor material?
By tmouse on 11/11/2009 7:35:44 AM , Rating: 2
I'm aware of the article, believe me most of those markers are NOT germ cell specific. I personally have seen many ovarian and spermatogenic "specific" markers appear in tissue culture induced cells in the hundreds of high throughput genomic screenings I have done. It's such an artificial system it is really stretching to make those conclusions. As I said before you do not want a 90% derived germ cell and they have less than a 10% if that. I'll concede my point when anyone can produce a germ cell that can even began to undergo meiosis, even if it results in a malformed gamete. I personally know most of the individuals who uncovered genomic imprinting and the complexities of this epigenetic modification system have not even been begun to be unraveled. We are now just starting to look into epigenetic methylation regulation and its interactions to coregulate cell state/function, mostly still ignoring imprinting.


RE: Donor material?
By drmo on 11/12/2009 9:39:17 AM , Rating: 2
I realize there is a lot of controversy in that study, which is why I said it may be possible, not that we are there. Also, cloning plus extraction of embryonic stem cells may allow one to create sperm much easier (some undergo meiosis, but those studies have been controversial as well and at least one was retracted). It seems to be a lot of trouble just to get one's own sperm produced, so it does seem a bit pointless. That's why I figured the point was more to have the Leydig (and Sertoli) cells present in the testes more than the sperm; but the correct feel may be even more important to those who have lost them. Apparently someone is funding the research, though; probably taxpayers.


"Well, we didn't have anyone in line that got shot waiting for our system." -- Nintendo of America Vice President Perrin Kaplan














botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki