It could have been part of a Jay Leno monologue. Perhaps it was. The latest miracle in biotechnology is a fully functional penis grown from an animals own cells. But this isnt just good news for Lorena Bobbitts next husband. No matter how you slice it, its a breakthrough for anyone who will ever need any type of solid organ replaced. As chief researcher Anthony Atala explained to New Scientist magazine, "The penis is more complex than any of the organs we have engineered so far."
Construction of organs from a persons own tissue is one of the hottest — and most vital areas of biotechnology. Sadly, its precisely because transplant techniques have improved that waiting lists for vital organs have tremendously lengthened. It stands now at 80,000 Americans. Last year alone, over 6,000 died on that list. That included a friend of mine who couldnt get a liver. He was 44.
You cant buy one on eBay, but there may be a biological artificial heart in your future.
As it happens, the first organ to roll off the assembly line is also the bodys largest. Europeans can already buy a novel skin graft called EpiDex™ from Swiss-based Modex Therapeutics to treat chronic skin ulcers suffered by over 13 million patients worldwide. With the standard autograft, the top of a sheet of skin is removed from a patient leaving both the donor and recipient sites with permanently thin skin and scars. EpiDex™ grafts, however, are grown from hair follicle stem cells. (So much for those who bizarrely continue to claim that adult stem cells will never work.)
Doctors pluck a few hairs; send them off, and voila! a few weeks later they receive back a set of skin disks. Clinical trials have shown EpiDex™ to be far superior in almost every way to the autografts in terms of area healed, cost, and discomfort to the patient. Further testing will be required before they get FDA approval.
The more complex organs, however, are made with scaffolding. Consider those penises. This organ comprises three main cylinders wrapped in an outer layer of connective tissue, skin, nerves, and blood vessels. The two biggest cylinders made of the spongy material that swells and hardens during an erection, are called the corpora cavernosa. The third tube holds the urethra. The cavernosa are the most complicated part of the penis, so that was the target of Dr. Atala.
As he reports in the October issue of The Journal of Urology, Atala and his colleagues first made collagen scaffolds from the erectile tissue of 18 rabbits. Then they extracted endothelial and muscle cells from the penis of each animal. They grew the cells separately at first then seeded them onto the scaffolding. Within just days they had something resembling the real thing.
Then the researchers cut away the corpora cavernosa from virtually the whole length of the 18 penises and inserted the erectile tissue. After recovery, the rabbits were put into cages with females. Knowing they have a reputation to maintain, the bunnies got right to business. "They were able to copulate, penetrate and produce sperm," Atala told New Scientist. This brings tremendous hope to many men who have been accidentally disfigured or were born with non-functional genitalia.
Multifaceted organs like hearts are further down the road, but work proceeds apace. Dr. Joseph Vacanti at Massachusetts General Hospital in Boston is one of the foremost researchers. He and his colleagues have taken a sheep heart, pumped its vessels full of liquid plastic, and then bathed the whole thing in flesh-eating enzymes. What looked like a Styrofoam ball turned out under a microscope to be filled with capillaries. MIT engineers have used specifications from the cast to design a full heart scaffold and eventually, like the bunnies bits, it will be seeded and made into a real organ.
Other scientists are building livers from the ground up, using nothing more than a small tissue sample. One such would etch networks of capillary-like grooves onto palm-sized silicon plates. Two casts lifted from molds of these plates would be sandwiched together, creating a three-dimensional template for interconnected vessels. These would then be filled with thousands of stacked layers of capillaries, liver cells, and bile-collecting vessels.
Another method of building organs, believe it or not, might make use of an inkjet printer thats rather more advanced than the one sitting next to your computer.
Biotech bladders in beagles work as well or better than the originals.
Therics, Inc. of Princeton, New Jersey starts with designs displayed on a computer screen as three-dimensional models, with the ability to include data from laser, X-ray, CAT or other scans. The final design is translated into compiled, computerized instructions. Then the TheriForm* device goes to work, laying down the construction material in a 3-D manner, instead of the 2-D pictures you get out of an ink jet printer. (For a "virtual tour," go to: http://www.therics.com/tour_n0.htm.)
TheriForm™ "can fabricate products composed of virtually any type of material and can combine a variety of different materials in ways that cannot be replicated with alternative technologies," the company claims. The current device employs multiple nozzles, each printing 800 micro drops per second, which then deposit binding material into a powder bed of biocompatible or resorbable materials.
For now, Therics is concentrating on relatively simple structures such as joint replacements that will fit recipients perfectly, replacing the primitive joint and screw combinations currently used. But just as ink-jet printers have progressed from producing nothing more than black type to spraying beautiful color photographs, so will Therics technology progress. The only question is how many organs youll get from a single cartridge before you have to go to the office supply store for a new one.
Eventually, people will be able to have "banks" of their own vital organs available for emergencies. Or they could use a cheaper alternative of having an organ constructed when the first signs of failure become apparent.
Regulatory policies alone essentially ensure that you wont be able to trade in a heart or a liver for a new or rebuilt one for at least five years. But the day is coming when no more 44-year-olds will helplessly perish while waiting for somebody else to die.
Read Michael Fumentos additional work on biotechnology.