Rat Limb Was Grown in the Lab
A team of researchers from the Ott Laboratory at Massachusetts General Hospital MGH grew the world’s first bioengineered rat limb. Bioartificial limbs might someday be suitable for transplantation.
Bioengineering techniques have been used previously to grow individual organs like hearts and lungs. But the researchers have been able to grow a whole animal limb.
The stem cells needed to grow tissue can be provided by a donor. What researchers hadn’t been able to work out until now, however, is how to construct a supporting structure known as the “matrix” or “scaffold”, which holds together all the things like bone, blood, cartilage, nerves, and muscle which make up limbs.
To make the new limb, the researchers used a technique called “decellularization” to strip the cellular materials from the forelimb of a dead rat, while leaving the nerve matrix and the primary blood vessels intact. Next up, the researchers injected muscle stem cells into the decellularized rat limb, which provides the structure onto which the new cells can grow. This is then cultured in a bioreactor. A suspension of muscle progenitor cells is injected into the cell-free matrix of a decellularized rat limb. “The composite nature of limbs makes building a functional biological replacement particularly challenging,” explained Harald Ott.
Both prosthetic technology and donor hand transplants are an option for patients. But they still have to face the lifelong risks of immunosuppressive therapy after transplant procedures, and prosthetics can have limitations in design and function. If limbs could be bioengineered in the future for those that need them, such setbacks could be reduced.