About 300 million people worldwide suffer from osteoarthritis, a common but as-yet-incurable disease of the joints. A new blood test developed following a scientific study by Hebrew University of Jerusalem researchers, however, could stop the disease from progressing, without forcing patients to be exposed to radiation in MRI imaging.
The arthritic disease, caused by an injury or degenerative processes that form throughout life, is accompanied by the wearing down of joints to varying degrees of severity. Although it is categorized as a disorder of old age due to its high prevalence among the elderly population (30 percent of sufferers are over 60), it is also common among young adults due to their bearing heavy loads or sports injuries – even in teens. It can even result from constant use of a particular joint.
Articular cartilage is a natural shock absorber and shielding material to protect the joint and skeleton. When it wears out, it exposes the bone beneath it, causing it to thicken and even to form an inter-articular connection that will restrict movement later. The process of cartilage erosion is accompanied by intense pain, local swelling, deformity of the joint and significant restriction of movement.
The disease cannot be diagnosed in its early stages, but only through advanced imaging tests such as MRI (magnetic resonance imaging), which can provide an accurate picture of the condition of the cartilage. The stages of diagnosis and imaging take a long time due to a limitation in the availability of MRI scanners, which also makes it difficult to develop a cure for the disease due to the limited time window for investigating the early stages of the disease.
Most patients today find some relief only from painkillers, which is not recommended for a long period because that they can become addictive or serious side effects including damage to the stomach and kidneys and hypertension. A significant proportion of patients will eventually need surgery to replace the joint with a titanium-based artificial prosthesis, with its major disadvantage being its durability for over 15 to 20 years.
In the Laboratory for Cartilage Research at the Hebrew University’s School of Dental Medicine, doctoral students George Batshon and Jinan Elayyan under the tutelage of lab director Prof. Mona Dvir-Ginzberg and Dr. Eli Reich have been working in recent years to develop a diagnostic tool for degenerative joint disease.
They have just published in the prestigious journal Annals of the Rheumatic Diseases that they found that a unique blood test for detecting the parts of the SIRT1 protein that change in the blood, and constitute a biomarker revealing the severity of the patient’s osteoarthritis. The ability to treat joint disease is difficult, and as time passes, the articular cartilage is destroyed, which will eventually lead to the surgical option, said Dvir-Ginzberg.
“The blood test we have developed may detect the stage the patients are in – even its early stages – in a time window when experimental drugs could benefit the patient,” she said. “We have information on endoscopic observations that characterize the severity of damage to a person’s joints and link the level of severity to the biomarker levels in the blood. We aim for the biomarker levels in the blood to be used as a substitute for an MRI scan.”
With the development of the disease, cells that have undergone a process known as “senescence” accumulate, preventing the cartilage tissue from regenerating and dividing. These cells are a kind of “zombie” cells that cause the death of their healthy neighboring cells. An experimental drug is currently in phase II trials effectively reduce the number of zombie cells in the damaged cartilage and prevent the death of the healthy cells and the development of the disease. This, said Dvir-Ginzberg, “can be seen by the decrease in the levels of the biomarker in the blood. In my opinion, the biomarker and drug treatment can change the lives of osteoarthritis patients.”
The Hebrew University research has gained financial support from the European Union, various companies have expressed their interest in the development.