Nearly one in three American adults suffers from some form of arthritis. For a variety of reasons, from aging to injury, cartilage erodes, causing painful, swollen joints. To relieve the pain, each year some 800,000 joint replacement surgeries are performed. An artificial mechanical joint is grafted into bone, most commonly replacing the hip, knee or shoulder joint.
The problem is the surgical solution doesn’t last. Younger patients often have to have it done over when the initial replacement wears out.
If Diane Wagner has her way, however, one day your own fat may help repair those aching joints for good. The Notre Dame assistant professor of aerospace and mechanical engineering is attempting to make integrated bone and cartilage from adult stem cells derived from fat.
The adult stem cells Wagner employs have the ability to develop into cartilage, bone, muscle, fat or tendons. Embryonic stem cells can develop into any cell in the body.
Adult stem cells from fat have several advantages over others, Wagner explains. Unlike embryonic stem cells, their use is universally regarded as moral. Also, acquiring them is less painful and invasive than those from bone marrow.
“They’re easier to get because they’re just below the skin, and, for better or worse, there’s usually more volume available,” Wagner says with a smile.
Using a single growth medium, chemicals that “tell” the stem cells how to develop, the ND mechanical engineer has successfully grown both bone and cartilage. Her approach is unique because traditionally different media have been used to develop different tissues.
“We’re using the same chemicals for both, just in different ways,” Wagner says. For bone, the stem cells are cultured in one layer on the bottom of a petri dish. For cartilage, the cells and medium are placed in a centrifuge and whipped around until they become a pellet. In the process, the cells attach to one another and develop into cartilage.
Wagner hypothesizes that different types of attachment trigger different responses in the stem cells. In turn, the varied responses initiate differing chemical chain reactions that lead to different development. “We think that’s at least part of what’s going on,” she says.
John Monczunski is an associate editor of Notre Dame Magazine.