For the first time ever, scientists have produced an entire limb complete with veins and muscle, in the lab.
The artificial rat limb is an exciting development for regenerative medicine as it brings us one step closer to generating fully functioning human limbs created from a patient's own cells, which would in theory make transplants more successful.
So how do you grow an entire limb in the lab?
In study published in the journal Biomaterials, researchers from the Massachusetts General Hospital outlined a recipe, of sorts.
They took a dead rat's limb and stripped it of all its cells leaving a matrix of veins and nervous tissue, which acts as a support system for the new cells.
They then placed the matrix in a device known as a bioreactor while scientists injected new cells into the matrix.
In order to ensure that the new limb developed normally, researchers injected vascular cells into the main artery and muscle progenitor cells (cells that are slightly more advanced than stem cells) into the areas of the matrix that are marked as muscle positions.
After following the development of the bioengineered limb for two weeks, scientists found that it was able to contract at 80 percent of the strength of muscle found in new born animals.
The limb's vascular system also functioned normally after being transplanted into a recipient animal. Bonus.
Harald Ott, a senior author of the paper explained the significance of the newly generated limb saying:
“Limbs contain muscles, bone, cartilage, blood vessels, tendons, ligaments and nerves – each of which has to be rebuilt and requires a specific supporting structure called the matrix. We have shown that we can maintain the matrix of all of these tissues in their natural relationships to each other, that we can culture the entire construct over prolonged periods of time, and that we can repopulate the vascular system and musculature.”
While Ott's result is a bioengineering feat, they are hoping that the same will one day be achieved with human cells.
He adds : "Additional next steps will be replicating our success in muscle regeneration with human cells and expanding that to other tissue types, such as bone, cartilage and connective tissue.”
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