Not long ago, medical scientists were struggling to figure out the best way to creating intelligent prostheses, a feat that has been successful with the help of bioengineers. The next mark to be conquered is now the “bioartificial” lab-grown limb that is viable for transplants on amputees.
A bioengineers team from the Massachusetts General Hospital (MGH) Department of Surgery and the Center for Regenerative Medicine has already made some progress in this direction. In a controlled lab environment, the team has created a rat forelimb with functioning muscle and vascular tissue.
Lead researcher of the project Harald Ott, MD, who is also the senior author of the paper, explained the great task they have to achieve. For a limb to be viable, it needs bone, muscles, cartilage, tendons, ligaments, blood vessels, and nerves.
The team had to make sure each one of these elements was rebuilt, along with its specific supporting structure called a “matrix.”
Donor hand transplants are the only alternative amputees currently have, and having such a transplant performed comes with a lifelong of immunosuppressive therapy. Despite making the amputee’s life a lot better, this kind of permanent medication is both risky and impractical.
The recipient of the limb can contribute to its creation with progenitor cells, the ones that stir the regeneration process. However, until now, the matrix helping cells grow and connect with each other was missing from the equation.
In their experiment, Dr. Ott’s team was able to maintain the matrix of all the tissues growing in natural relationships to each other, creating a construct cultured over long periods of time. Moreover, they also managed to repopulate the musculature and the vascular system.
Using animal progenitor cells, the bioengineers team successfully rebuilt hearts, livers, kidneys and lungs. However, the rat’s bioartificial limb is the first ever to achieve completion in all of its complex tissues.
Over a week’s time, the team used a detergent that helped eliminate the limb from cellular material. After this process was complete, the preliminary structure – the remaining matrix – proved to be cell-free and ready to receive muscle and vascular cells previously cultivated in lab conditions.
After veins and arteries were rebuilt and injected into the limb, researchers added muscle progenitors, resulting in an 80 percent of the strength a rat limb has at birth.
Just in the United States there are more than 1.5 million people who have lost a limb, so improving the functions and appearances of prosthetics is a top priority for many bioengineers teams.
Image Source: Digital Afro