Joints are designed for hard work. We stand for hours; we lift and bend and open jars with tight lids. We can stay active because healthy cartilage is smooth and squishy enough to withstand daily wear and tear. Unfortunately, cartilage doesn’t stay healthy in everyone.

Tiny defects in cartilage from injury, wear and tear or excessive weight gain, worsen over time. Pain changes how we walk, which in turn, puts too much pressure on the frayed edges of worn cartilage. And when cartilage becomes damaged, it can’t heal on its own, which can lead to osteoarthritis. However, researchers are finding ways to help cartilage heal by mimicking biology in the laboratory.

One group at Case Western Reserve University’s Department of Biomedical Engineering in Cleveland, Ohio, led by Eben Alsberg PhD, associate professor in biomedical engineering and orthopedic surgery, has found a new way to grow sheets of cartilage in a petri dish. The laboratory-grown cartilage (or neocartilage) can potentially be used to fill the “potholes” in damaged cartilage and perhaps prevent osteoarthritis.

Their research was recently published in the Journal of Controlled Release.

Turning cells into cartilage

Growing cartilage or any other tissue in the laboratory is tricky. Cells are accustomed to a particular environment. Researchers trying to raise cells in a petri dish when they’re used to the human body need to figure out the right mix of nutrients and growth conditions that will mimic the cell’s natural environment, a  process that can take weeks of specialized conditions and equipment.

For Alsberg and his team, their goal is to “try to shorten in vitro culture time and simplify the process, to apply this technique to the clinical setting more rapidly,” he says.

The team starts the cartilage making process with mesenchymal stem cells, immature cells from bone marrow that can change into a variety of cell types depending on which nutrients are added. Under the right conditions the mesenchymal stem cells can morph into cartilage cells (chondrocytes), which work like tiny factories to produce matrix, the glue that helps hold cartilage together.