Cartilage tissue engineering

by Allison Van Winkle

In the body, cartilage has minimal potential to heal itself once damaged, as the tissue is not naturally exposed to a blood supply, and is then prevented from benefiting from the body’s immune response and wound healing capabilities. By using a tissue engineering approach, researchers hope to develop replacement cartilage that can be transplanted into a patient to stimulate the regeneration of the native tissue. 

In particular, patients suffering from osteoarthritis, where the joint cartilage has worn down over time, may particularly benefit from cartilage regeneration, as opposed to current treatment methods which range from pain medication to artificial joint replacements.

A tissue engineering approach will generally combine a cell source, biological growth or differentiation factors, and a biocompatible scaffold to grow the cells on. One proposed scaffold for cartilage tissue engineering involves using natural materials derived from healthy cartilage tissue, known as extracellular matrix. 

A recent study published in Biomaterials reports that the extracellular matrix scaffold strongly supports cartilage cell development. The researchers used rabbit mesenchymal stem cells in combination with an extracellular matrix scaffold, developed from healthy porcine cartilage, and found that cartilage-cell development from the mesechymal stem cells occurred earlier in the extracellular matrix scaffold, and produced more cartilage-like tissue compared to a synthetic scaffold.

One complication of this method is that it is difficult to reproduce the exact conditions; as the matrix was derived from a variable animal cell source, the exact composition of the scaffold, as well as mechanical properties and porosity are likely to vary in some degree in each experimental run. The effects of this variation, however, may not impact cartilage cell formation, as the animal-derived matrix outperformed the more defined synthetic scaffold. 

Future related research will hopefully further examine this potential variability, and apply these findings to human tissue.

Comments

[Chris Kamel]

There have been a couple of recent papers in high profile journals dealing with scaffold-based regenerative medicine.

The first is a Nature Medicine paper using adult hepatocytes to repopulated a decellularized liver matrix for liver transplants: http://www.nature.com/nm/journal/vaop/ncurrent/abs/nm.2170.html

The second is from Science, and successfully grew and transplanted scaffold-grown lungs in a rat, where they were functional and participated in gas exchange: http://www.sciencemag.org/cgi/content/abstract/science.1189345v2

Very cool stuff!