Tissue engineering of human cartilage has proved problematic, although researchers at Columbia Engineering have made a breakthrough.
Cartilage has long been considered to be an ideal candidate for tissue engineering. Cartilage only has one cell type, there are no nerves and no blood vessels. Engineering the tissue in vitro should therefore be a much simpler process than generating other types of human tissues but biomedical researchers have discovered the process is far from simple.
However, a team of researchers from Columbia Engineering have made a remarkable breakthrough and have successfully generated fully functional human cartilage in vitro for the first time.
Progress had previously been made using young animal cells. Researchers were able to develop piece of cartilage, but attempts to generate cartilage from adult human stem cells taken from fat or bone marrow failed to produce strong cartilage.
Previous attempts to generate cartilage cells have involved culturing cells in hydrogel with various nutrients and growth factors. Since cartilage is a load bearing tissue, researchers have also tried using growing cartilage with mechanical loading.
Tissue engineering of human cartilage from adult stem cells using the above techniques have been tried in the past, but the cartilage that has been generated was found to be structurally weak.
It was clear that in order to produce cartilage with physiologic architecture and strength a different approach was required. Gordana Vunjak-Novakovic, lead researcher and Mikati Foundation Professor of Biomedical Engineering at Columbia Engineering, chose a radically different method.
Sarindr Bhumiratana, a postdoctoral fellow in the Laboratory for Stem Cells and Tissue Engineering at Columbia Engineering came up with the new methodology which mimics the natural process of generating cartilage in the body. Mesenchymal stem cells were induced to undergo a condensation stage as they do in vivo and the results were impressive. Using the new technique it was possible to generate fully functional human cartilage from mesenchymal stem cells for the very first time.
Vunjak-Novakovic said “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.”
Vunjak-Novakovic and her team now plan to test their engineered cartilage in situ and will be using the engineered tissue to repair defective cartilage and assess whether it maintains its structure over the medium to long term.
The study was recently published in Proceedings of the National Academy of Sciences (PNAS) this April.