04 June 2015

The world's first rat's foot from a bioreactor

Scientists have grown the first artificial rat leg

RIA NewsBiotechnologists from Harvard University have successfully created the world's first artificial rat limb by growing its muscles, vessels and other components from stem cells, according to an article published in the journal Biomaterials (Jank et al., Engineered composite tissue as a bioartificial limb graft – VM).

"Our limbs contain muscles, bones, cartilage, blood vessels, ligaments, nerves and other things, each of which has its own "framework" that supports their shape. We have shown that we can keep them in the form and position in which they are in the hands and feet, maintain them in this state indefinitely and use them for re–growing, at least, vessels and muscles," said Harald Ott from Harvard University (in a press releaseThe Massachusetts General Hospital MGH team develops a transplantable bioengineered forelimb in an animal model – VM).

Ott and his colleagues have been working for several years to create artificial versions of damaged organs. Two years ago, they created an ingenious technique that allows you to grow healthy copies of kidneys, using a diseased organ as a "framework" for the growth of stem cells.

According to the Ott method, the damaged organ is first treated with a combination of chemicals that destroy the cells and leave the connective proteins framing them.

Then this "template" is filled through the former arteries and urinary tract with "blanks" of kidney cells and vessels extracted from the rat embryo. Artificial lungs, heart, liver and a number of other organs were grown in a similar way.

Using this technique, the Ott group prepared the skeleton of a rat's leg, and tried to use it as a template for a bionic limb. Scientists did not set themselves the initial task of growing the whole leg, and therefore focused their attention on the two heaviest parts of the limb – muscles and blood vessels.

By placing the "frame" and a set of stem cells of muscles, blood vessels and connective tissue in a special bioreactor, scientists received a full-fledged limb in a few weeks, except for the nerves missing in it.

To test the leg's performance, scientists connected electrodes to its muscles, which caused the limb to contract when current was applied. The fingers, joints and individual muscles of the artificial leg moved successfully, and, according to the calculations of the authors of the article, they had comparable strength compared to the limbs of a newborn rodent.

Now scientists are trying to grow an artificial primate arm in the same way, using an amputated baboon limb as a "frame", and also thinking about how to solve the problem with the germination of nerve endings in the limb.

According to Ott, this problem can be solved by itself. "When transplanting limbs in clinics, nerves often grow from the stump into the implanted leg or arm, which allows the patient to feel and move them, and we found out that this recovery process also depends on the "frame". We hope that in the future we will be able to use this feature of the body when creating full–fledged artificial limbs," the scientist concludes.

Portal "Eternal youth" http://vechnayamolodost.ru04.06.2015

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