Could that ache in your knee or back be osteoarthritis? Are you having trouble opening jars? A new biochemical test called metabolomics could allow clinicians to diagnose osteoarthritis early and let patients get a jump on treating and managing the disease.
Osteoarthritis is the most common type of arthritis, far surpassing rheumatoid arthritis and gout in prevalence. In the United States, approximately 27 million adults have osteoarthritis, according to the Arthritis Foundation, and in the United Kingdom, where the new study was conducted, the disease affects approximately 8.5 million people.
Researchers at King’s College London’s Department of Twin Research and Genetic Epidemiology have discovered a new biochemical test that allows scientists to test for 163 chemical signals from a single blood sample. Called metabolomics, the test measures chemical signals that are products of cell metabolism and their 26,000 metabolite ratios, which represent the rate of the chemical reactions in the body.
The researchers compared the metabolites and the 26,000 metabolite ratios in the blood samples from 123 white women who had osteoarthritis of the knee and 299 healthy women. They discovered that 14 metabolite ratios were significantly linked with osteoarthritis. When the scientists tested these signals in 76 women with knee osteoarthritis and 100 healthy women, they found that two ratios—valine to histidine and xleucine to histidine—were confirmed.
The study’s lead author, Dr. Guangju Zhai, explained that “the two novel metabolic biomarkers found through our study could indicate increased cartilage breakdown and we now want to study these mechanisms in more detail.” Osteoarthritis is known as “wear and tear” arthritis, as one of its main characteristics is damage to the cartilage that lines the bones and allows the joints to move without friction.
Although it is easy to diagnose advanced osteoarthritis, early detection has been a challenge and relies on x-rays and scans, which are not reliable. With early detection, clinicians could prescribe medication, dietary supplements, or other ways to help prevent further cartilage damage.
In 2008, researchers from Tel Aviv University and New York University reported they had developed a new application of magnetic resonance imaging (MRI) technology that allows a non-invasive early diagnosis of osteoarthritis. The technique allows clinicians to follow the amount of proteoglycans in the joints. Proteoglycans are a main constituent of cartilage. During the first stage of osteoarthritis, proteoglycans begin to disappear from cartilage.
Senior author of the King’s College study, Professor Tim Spector, noted that he hopes further research will result in the two discovered metabolite ratios being adopted by physicians and enable them to diagnose osteoarthritis early or identify that the disease is developing, earlier.
King’s College London
Ling W et al. Proceedings of the National Academy of Sciences of the USA 2008 Feb 19; 105(7): 2266-70