Stanford will shine another spotlight on the curative potential of stem-cell technology this year with an innovative approach to treating damaged cartilage and osteoarthritis. Already enthused by results from the lead-up work, Jason Dragoo, associate professor of orthopaedic surgery, is preparing to launch a human trial for restoring articular cartilage at the knee joint.
The trial, involving 40 patients, uses cells taken from the fat pad under the knee and concentrates them in the lab to produce therapeutically friendly progenitor cells—also called adipose-derived stem cells. For 20 of the patients, these cells will be used to surgically target distinctly identified defects in the articular cartilage, the movement-aiding tissue at the end of joints. This approach, says Dragoo, is like trying to fix holes in a tire, as opposed to methods for resurfacing "treadwear" all along the cartilage.
The other 20 patients will undergo a standard procedure that releases cells by surgically creating microfractures in the knee bone, with the goal of generating new cartilage as well as easing pain from worn tissue. Each group of 20 will be randomly selected; participants and analysts will not know who is receiving one treatment versus the other. The results will be monitored and studied over two years.
Damage to articular cartilage, either from specific injury or deterioration over time, leads to osteoarthritis, which causes inflammation, pain and stiffness in various joints for tens of millions of people worldwide. It is a progressive condition without a cure, interfering with routine activities and often necessitating knee or other joint replacements using artificial material.
Dragoo's excitement about the trial—which is structured according to federal rules for conducting stem cell research—has been heightened by the lab work that derives the progenitor cells from the extracted fat. "Out of the centrifuge," Dragoo reports, progenitor cells have constituted 90 percent or more of the separated cells. "I was floored," he says, noting by comparison that only a tiny percentage is collected when they're culled from bone marrow. "At first I thought we'd made a mistake."
The stem cells are joined with what's known as a matrix, or scaffold, of biologic material that supports tissue growth. Then comes surgical implantation. Ideally, Dragoo explains, the results for the patients will be "more regenerative—not only to feel better, but to document that there's regrowth." Big "ifs" accompany most of the efforts in this field of medicine. But the hope, says Dragoo, is that the procedure "may improve results from the current gold-standard microfracture in many ways. . . . This technique does not breach the bone below the cartilage, so may avoid the bone complications associated with microfracture."
Dragoo, who is also the head physician for the Stanford football team, says other potential advancements include the 3-D printing of replacement cartilage. But that's even farther away. And all those potholes can't wait.
