In a pioneering work, researchers at Columbia Engineering have successfully grown fully functional human cartilage from human stem cells derived from bone marrow tissue.
"We have been able to generate fully functional human cartilage from mesenchymal stem cells by mimicking in vitro the developmental process of mesenchymal condensation," explained Gordana Vunjak-Novakovic, the Mikati Foundation professor of biomedical engineering at Columbia Engineering.
This could have clinical impact, as this cartilage can be used to repair a cartilage defect, or in combination with bone in a composite graft grown in lab for more complex tissue reconstruction, he informed.
The general approach to cartilage tissue engineering has been to place cells into a hydrogel and culture them in the presence of nutrients and growth factors and sometimes also mechanical loading.
But using this technique with adult human stem cells has invariably produced mechanically weak cartilage.
So Vunjak-Novakovic and her team wondered if a method resembling the normal development of the skeleton could lead to a higher quality of cartilage.
They came up with a new approach - by inducing the mesenchymal stem cells to undergo a condensation stage as they do in the body before starting to make cartilage.
"Our whole approach to tissue engineering is biomimetic in nature, which means that our engineering designs are defined by biological principles," Vunjak-Novakovic noted.
This approach has been effective in improving the quality of many engineered tissues - from bone to heart.
"Still, we were really surprised to see that our cartilage, grown by mimicking some aspects of biological development, was as strong as 'normal' human cartilage," she emphasised.
The team now plans to test whether the engineered cartilage tissue maintains its structure and long-term function when implanted into a defect.
The study has been published online in the journal Proceedings of the National Academy of Sciences (PNAS).
