For Angela Bohannon, a 38-year-old real estate agent from Middle Tennessee, a diagnosis of osteoarthritis (OA) from her general practitioner wasn’t a complete surprise. The former high school basketball standout had suffered pain in her right knee off and on since injuring her anterior cruciate ligament (ACL) during an especially competitive game in her senior year of high school. The injury dashed her hopes of playing basketball in college and caused her to live with chronic pain, despite treatment and physical therapy.
Over the course of the last five years or so – roughly 15 years since her initial injury – Bohannon, who spends much
of her day driving to and walking through the homes she shows, began to notice increasing levels of pain, stiffness
and an increase in downtime caused by the pain. “If I was planning to show several homes in one day or knew I’d be
showing homes with a lot of stairs, I would just load up on ibuprofen,” she says.
When she began having to cancel appointments due to her pain, Bohannon saw her doctor, and was ultimately diagnosed with a type of OA known as post-traumatic arthritis, or PTA. With that diagnosis, Bohannon’s doctor was able to craft a treatment regimen including anti-inflammatories, pain medicine and physical therapy, allowing her to enjoy more pain-free days.
Thanks to a team of researchers at Duke University, whose research was funded jointly by the Arthritis Foundation and the National Institutes of Health, future athletes may never have to endure the pain and debilitation caused by PTA that Bohannon
and countless other athletes suffer.
On August 10, the journal Cell Transplantation published a study by Farshid Guilak, PhD, director of orthopaedic research at Duke
and senior author of the study*, which indicated that researchers at Duke University Health System had found a very promising
therapeutic approach to PTA using a type of stem cell, called mesenchymal stem cells (MSCs). The study involved mice with fractures that would typically lead to development of arthritis. The researchers’ findings could lead to a therapy for after-joint-injury, but before signs of significant OA.
The researchers also thought that a type of mice bred for their super-healing properties would probably fare better than typical mice, but they were wrong.
“We decided to investigate two therapies for the study,” says lead author Brian Diekman, PhD, a postdoctoral researcher in the Guilak lab. “We thought that stem cells from so-called ‘superhealer’ mice would be superior at providing protection. Instead, we found that they were no better than stem cells from typical mice. We thought that maybe it would take stem cells from superhealers to gain an effect as strong as preventing arthritis after a fracture. But we were surprised – and excited – to learn that regular stem cells work just as well.”
According to Guilak, professor of orthopaedic surgery and biomedical engineering, certain people also appear to
have “superhealer” properties, bouncing back and healing more quickly following a fracture, while others are slower to heal and develop arthritis at the fractured joint.
“The ability of the superhealer mice to have superior healing after a fracture may go
beyond the properties of their stem cells and be some beneficial factor — like a growth factor that we don't know about
yet," Guilak says.
The delivery of 10,000 typical or superhealer stem cells to the joint prevented the mice from developing PTA, unlike a control group that received only saline.
Diekman says the team looked at markers of inflammation and saw that the stem cells affected the inflammatory
environment of the joint after fracture.
“The stem cells changed the levels of certain immune factors, called cytokines, and altered the bone healing response,” explains Diekman, who is also with the Duke Department of Biomedical Engineering.
Guilak says that very few studies have purified stem cells to the degree they were purified for this study. They used mesenchymal stem cells, which are bone marrow cells not destined to become part of blood.
Diekman points out that one of the challenges in the field is isolating and developing a system for sorting the specific
cells they wanted, the mesenchymal stem cells, which form a very rare cell type in the bone marrow.
“We found that by placing the stem cells into low-oxygen conditions, they would grow more rapidly in culture so
that we could deliver enough of them to make a difference therapeutically,” Diekman concludes.
While it may come too late for Bohannon and other athletes of her generation, this exciting new therapy holds great potential for future athletes, those in the military, and anyone else with the potential for developing OA as the result of an injury.
*Other study authors include Craig R. Louer, Bridgette D. Furman and Steven A. Olson of the Duke Department of Orthopedic Surgery; Chia-Lung Wu of Orthopedic Surgery and the Department of Biomedical Engineering; and Janet L. Huebner and Virginia B. Kraus of the Duke Department of Medicine