Thanks to earlier diagnosis and more effective treatments, joint deformities in people with rheumatoid arthritis (RA) are becoming less frequent and severe.
What Causes Joint Deformities in RA?
In a joint affected by RA, inflammatory cells of the immune system gather in the lining of the joint (called synovium), forming a fibrous layer of abnormal tissue (called pannus). The pannus releases substances that quicken bone erosion, cartilage destruction and damage to the surrounding ligaments. The involved joints lose their shape and alignment, resulting in deformities. Severe deformities lead to loss of joint function and the need for joint replacement surgery.
For decades, X-ray images have been used to help detect rheumatoid arthritis (RA) and to monitor for the progression of bone damage. In early RA, however, X-rays may appear normal although the disease is active – making the films useful as a baseline but not much help in getting a timely diagnosis and treatment.
Enter modern imaging techniques, including ultrasound and magnetic resonance imaging (MRI), which can reveal early, non-bony signs of RA that are invisible on X-ray.
“Both MRI and ultrasound are more sensitive at detecting bone erosion than X-ray. In addition, they also reveal inflammation, which we could not see directly before and had to rely on blood tests and using our fingers to feel the joints,” says rheumatologist Philip Conaghan, MD, PhD, professor of musculoskeletal medicine at the University of Leeds and president of the International Society for Musculoskeletal Imaging in Rheumatology.
Neurosurgeon Kevin J. Tracey, MD, president and CEO of the Feinstein Institute for Medical Research in Manhasset, N.Y., discovered that stimulating the vagus nerve, which extends from the brain stem to the stomach, could control the inflammation that is central to RA.
In healthy people, the nervous system, including the vagus nerve, maintains key bodily functions within a safe zone. One of the vagus nerve’s jobs is to control the production of tumor necrosis factor (TNF), a molecule that triggers inflammation. But in people with RA, the vagus nerve doesn’t keep TNF levels within the safe zone.
An emerging class of medications called janus kinase inhibitors (JAK inhibitors, or jakinibs) is offering new hope to patients with rheumatoid arthritis (RA) who don’t find relief with other treatments.
What are Jakinibs?
Jakinibs are a new class of medication, sometimes called oral biologics. The word “biologic” is misleading, however, because jakinibs work in an entirely different way than the biologics that have been used to date. Jakinibs are small molecules that work inside cells. Traditional biologics such as etanercept (Enbrel), adalimumab (Humira), abatacept (Orencia) and Infliximab (Remicade) block pro-inflammatory cytokines from outside.
Jakinibs are taken by mouth. Traditional biologics are given through infusions or injections.