Scientists Successfully Grow a Rat Limb In A Laboratory. Sights Set For Bigger Limb Next
Massachusetts – It seems like just yesterday scientists were able to grow the first human ear on the back of a lab mouse. Today they are able to grow entire limbs in a petri dish using living cells. Scientists at the Massachusetts General Hospital announced that they were able to successfully achieve this using a technique called “decel/recel” or decellularization and recellularization to grow things like hearts and lungs.
The process of growing a limb is fairly straight forward: scientists take the limb of a dead rat get rid of all of its cells. The decellularization leaves just some basics materials like collagen proteins. The reason for doing this you improve the chances of the host accepting the new part because there are no living cells remaining from the original donor.
Harald Ott’s lab at Massachusetts General Hospital explains the process a little more in-depth here:
A forearm is much more difficult to create in this way than a windpipe, say, as a number of different cell types need to be grown. Ott began by suspending the decellularised forelimb in a bioreactor, plumbing the collagen artery into an artificial circulatory system to provide nutrients, oxygen and electrical stimulation to the limb. He then injected human endothelial cells into the collagen structures of blood vessels to recolonise the surfaces of blood vessels. This was important, he says, because it made the vessels more robust and prevented them from rupturing as fluids circulated.
Next, he injected a mixture of cells from mice that included myoblasts, the cells that grow into muscle, in the cavities of the scaffold normally occupied by muscle. In two to three weeks, the blood vessels and muscles had been rebuilt. Ott finished off the limb by coating the forelimbs with skin grafts
Next on the grow list, a primate limb
Scientists have their sights set on the obvious next step in the regrowing process, which is the primate limb. The difficulty of growing a primate arm will be more of a challenge to recellularize the larger and more complex limb. The hopeful outcome of this will be to understand the process which should then lead to understanding how to regrow human limbs and organs.