Rheumatoid arthritis implants release drugs when they sense inflammation

Researchers at Washington University School of Medicine have tested an experimental new treatment for rheumatoid arthritis in mice. The team implanted stem cells that have been reprogrammed to secrete anti-inflammatory drugs only when they sense inflammation.

Rheumatoid arthritis is an autoimmune disorder where the immune system mistakenly begins attacking tissue at the joints. Inflammation makes movement of the joints painful and restrictive, causing damage to cartilage and eventually bone. The condition occurs in flare-ups of inflammation, and can be debilitating and hard to treat.

“Doctors often treat patients who have rheumatoid arthritis with injections or infusions of anti-inflammatory biologic drugs, but those drugs can cause significant side effects when delivered long enough and at high enough doses to have beneficial effects,” says Farshid Guilak, senior investigator on the new study.

One of the main problems for these types of drugs is that they don’t stick around in the right spot for long enough to have much of an effect. So for the new study, the Washington University team investigated a way to keep drugs focused on the right spot for longer, by combining two previous technologies.

The researchers started with what they call Stem cells Modified for Autonomous Regenerative Therapy (SMART) cartilage cells. Essentially, these are cartilage cells that contain induced pluripotent stem cells (iPSCs) that have been engineered so that they can sense inflammation around them and respond by releasing an anti-inflammatory drug. These SMART cartilage cells are then embedded into a scaffolding material that can be implanted into joints.

“The cells sit under the skin or in a joint for months, and when they sense an inflammatory environment, they are programmed to release a biologic drug,” says Guilak.