How to grow a hip replacement with your own stem cells

St. Louis Public Radio | By Durrie Bouscaren,

Durrie Bouscaren

Published July 18, 2016 at 2:59 PM CDT

Washington University biomedical engineering PhD student Ali Ross and Farshid Guilak, PhD, a professor of orthopedic surgery, show a container with a prototype of a living hip replacement.

A St. Louis orthopedic researcher has developed a way to grow a hip replacement out of stem cells found in a patient’s fat reserves, and is now testing it in animals.

The discovery that made it possible happened by accident, said Farshid Guilak, who directs regenerative medicine research for St. Louis Shriner’s Hospital and Washington University.

Fifteen years ago, a friend of Guilak's who worked for a company that supplied fat cells to researchers told him about an office mishap.

“He told me he accidentally left some cells in the back of his incubator for a couple of weeks, forgot about them, and they made some mineral, like bone,” Guilak recalled. “He thought it was nothing, and they were going to throw out the cells.”

But Guilak thought exposing those cells to certain proteins could help them grow into cartilage. He was right.

A 3-D, biodegradable, synthetic scaffold has been molded into the precise shape of a hip joint. The scaffold is covered with cartilage made from stem cells taken from fat beneath the skin.

“A lot of science, for better or worse, happens by accident," he said. "And sometimes you’re lucky enough to be there.”

Over several years, Guilak and his colleagues created woven polymer models for the cells to grow on, shaping them into joints made of living cartilage instead of plastic or metal.

About 332,000 total hip replacements are made in the United States every year, according to the Centers for Disease Control and Prevention. High rates of obesity and arthritis mean that people in their 40s and 50s are needing hip replacements more often, Guilak said. A hip made of living tissue could last longer than one made of metal or plastic, because they can wear out.

“What we wanted to develop was a living replacement that could — if nothing else — delay a metal and plastic replacement for 10 or 15 years,”Guilaksaid. “But even, potentially, a permanent replacement that could even grow with a patient if it’s a child, and adapt to changes in their joint over time.”

Guilak’s models are now being tested in hound dogs, which also develop hip issues. If all goes well, he and his colleagues hope to conduct human safety studies in three to five years.

Follow Durrie on Twitter: @durrieB.