The initial blood test for early-stage osteoarthritis could shortly be developed, say scientists who recommend the biomarker they have recognized can identify the painful joint problem prior to bone damage occurs.
The study, lead by the University of Warwick in the UK, is presented in the journal Scientific Reports.
The authors identified that examining for citrullinated proteins (CPs) in the blood could guide to osteoarthritis (OA) being diagnosed years prior to physical symptoms appear.
They also identified that CPs may provide as a reliable way to identify early-stage rheumatoid arthritis (RA).
Lead investigator Dr. Naila Rabbani, reader of experimental systems biology at Warwick, states that:
“This is an amazing and surprising finding. It could assist bring early-stage and suitable therapy for arthritis, which provides the best possibility of effective treatment.”
Dr. Rabbani and colleagues note that while there are well-known biomarker tests for early-stage RA, there are not one for OA and recommend their results could result in a test for both that also differentiates between the two.
CPs elevated in sufferers with early-stage OA, RA
Osteoarthritis is a joint disease connected with aging. It develops when the protective cartilage layer within joints wears away because of constantly being stressed over a person’s lifetime. This kind of arthritis generally affects the knees, hips, fingers and lower spine and infrequently strikes prior to the age of 60.
The World Health Organization (WHO) calculate that around 9.6% of men and 18.0% of women above 60 have symptomatic osteoarthritis.
RA is a chronic systemic condition that impacts not only the joints but also muscle, connective tissue and fibrous tissue. It is a disabling situation that usually leads to pain and deformity and is likely to strike between the ages of 20 and 40.
With respect to WHO, RA impacts up to 3% of the international population. The condition is more common in women and in developed nations, where about half of individuals who develop it are not capable to have a full-time job within 10 years of onset.
For their research, the investigators developed a technique based on mass spectrometry to determine CPs in body fluids. They identified that CPs were raised in sufferers with early-stage OA and early-stage RA.Earlier research had already established that individuals with RA had antibodies to CPs, but these have not been identified in early-stage OA.
Single blood test to identify and differentiate the two main types of arthritis in early stages
In the next level of their work, the team designed an algorithm that combined three biomarkers – CPs, anti-CP antibodies and hydroxyproline, a bone-derived substance – into one test.
Using the algorithm, they identified that with a single blood test they could possibly identify and differentiate between the two kinds of arthritis prior to bone damage took place.
Dr. Rabbani describes that the algorithm uses the existence of autoimmunity to CPs in early-stage RA (antibodies are present) and the lack of such autoimmunity in early-stage OA (no antibodies) to differentiate between the two.
She describes that the team would have been pleased with discovering the foundation of a test for OA – but also discovering they could differentiate between early-stage RA and other joint diseases was an additional bonus:
“This discovery increases the possible of a blood test that can help identify both RA and OA several years prior to the onset of physical indications.”