It’s a story that we’ve heard all too often. On House, Scrubs, ER, Grey’s Anatomy, and even sometimes in real life, a patient needs a liver but there’s no compatible donor on the list. The problem stems from the fact that even if every eligible body donated their organs, there will still always be a greater demand than there is a supply. We simply don’t have enough livers in this country to go around. This might not be a problem for long. Recent medical breakthroughs are showing great hope for organ “farming”, literally growing any necessary organ on demand.
Sometimes people don’t realize just how fast science is progressing, but look back twenty years ago when cloning was just a promise, when everyone imagined a future full of identical twins and Dolly was the most amazing symbol of scientific power since we put a man on the moon. Now it’s common enough that the FDA had to officially give their approval for the production of cloned beef. For the past decade scientists have regularly been not just been growing full test tube creatures but even tweaking their DNA to fit our needs. Goats are making spider silk, rabbits and pigs are glowing like fireflies, and now Professor Esmail Zanjani at the University of Nevada's School of Medicine has created what might be the most useful and the most eerie modified animal in the history of cloning: sheep that have human organs.
No, this isn’t some sort of half man, half sheep monster, what Dr.Zanjani has done is breed what is known among geneticists as a chimera. Chimerism is a genetic disorder that causes an organism to have two sets of genetically distinct organs. This condition has been known to cause hermaphrodites when the gonads are split between male and female, as well as causing many interesting custody trials. An interesting feature of chimerism, however, is that the two cell types don’t have to be from the same species. As long as the species lives, any combination is possible, which is what led Dr.Zanjani to consider growing human organs inside of a sheep. He makes these chimerae by injecting stem cells from bone marrow in specific places in a sheep fetus. You’ve probably heard about stem cells from the news, but if you haven’t stem cells are hailed as the current hot topic in biology. This is because they are incredibly versatile and can be coaxed to form basically any organ. Put them in the right places, and apparently, they can even grow human organs in sheep.
Now, this technology is still in its infancy. Currently the best organ in Dr.Zanjani’s sheep is only 15% human, and he hopes to make one soon that is 50%, but ideally we’d like to have one that is 100% Homo Sapien. Why not make it even better and have this organ be genetically identical to the one you had before?
Doctors at Wake forest have actually done just that. They have discovered a method that use the patient’s own cells to grow a custom organ that is a perfect, functioning duplicate of the his/her original. It was first performed a few years ago when medical scientists were able to grow new bladders for seven patients with myelomeningocele, a disorder that can lead to osteoporosis, kidney stones, and even cancer. Doctors at Wake Forest extracted small samples from the patients bladders and surround muscles and cultured them in a bladder-shaped mold. Eight weeks later, the patients had perfect bladders with no risk of blood mismatch that functioned flawlessly.
Theoretically, these methods could work with any organ, save the brain, and if it works as well as these researchers claim it might this could be one the most important scientific breakthroughs of all time. If we had the power to grow organs on demand, then their use wouldn’t be limited to just those who needed them, but those who wanted them. Wealthy men and women with weak bones or hearts could simply buy new organs to replace their aged ones. A new breed of plastic surgeons would develop who could actually cure aging, not with chemicals our nips and tucks but genuine youthful organs. Currently we don't know exactly how long the human brain can last, but if scientists find a way to keep it from degenerating into senility then the possibilities arelimitless. Immortality could be in our future.
http://www.payvand.com/news/07/apr/1009.html
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