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Scientists have managed to grow bone from stem cells for the first time

Gordana Vunjak-Novakovic, a professor of biological medicine at Columbia University, was the first to grow a whole bone from adult human stem cells. The prototype was the temporomandibular joint (TMJ), which was grown from stem cells obtained from bone marrow. Professor Vunjak-Novakovic shares the results of his achievement in the April issue of the Proceedings of the National Academy of Sciences.

The temporomandibular joint, which connects the lower jaw to the base of the skull, was not chosen as a sample for the experiment by chance. It has a very complex shape, and it is extremely difficult, if not impossible, to reproduce it qualitatively using currently existing methods of transplanting other bones. Currently, the most common treatment for TMJ injuries is to graft bones from patients' legs or hips.

“If we managed to grow the TMJ,” explains Gordana Vunjak-Novakovic, “then we can get bones of any shape and form.”

As complex as the temporomandibular joint is, it is so important - every fourth American, for example, has some form of TMJ disease. They can be caused by cancer, birth defects, trauma, arthritis, etc. So the ability to grow this important joint from the patient’s own stem cells opens up great opportunities for doctors.

Vunjak-Novakovic helped develop the technique of growing TMJ from stem cells through the body's natural process of creating bone. The Columbia University professor began her work with a thorough analysis of digital images of the jaws of patients. At the first stage, it was necessary to create a frame for further placement of stem cells on it, which would exactly match the shape of the temporomandibular joint. Such a frame was eventually made from human bone, from which all living cells had been removed.

Having made a frame, scientists “seeded” it with stem cells taken from the patient’s bone marrow and placed the frame in a bioreactor built specifically for this purpose. The reactor was filled with growth medium, a substance used to grow organisms in the laboratory that nourishes and physically stimulates cells to turn into bone.

Metabolic processes in bone tissue are very active. It is known that it grows best when in a liquid medium. Gordana Vunjak-Novakovic and her colleagues determined the optimal fluid flow at which the fastest growth occurs. It took five weeks to grow a 4cm TMJ that is exactly the same size and shape as the temporomandibular joint.

This technique, of course, can be applied to growing other bones, including the skull and cheekbones, which are as difficult to reconstruct as the TMJ.

Now Gordana Vunjak-Novakovic is working on how to connect the new joint to the human blood system so that it grows with its owner.

Zakhar RADOV