Biomarkers discovery offers hope of new osteoarthritis test
27 April 2010
The new test, developed by scientists at King's College London, looks at 163 chemical signals at the same time from a single blood sample. The 26 000 ratios at which these molecules appear represent the rates of chemical reactions in the human body.
The team studied 123 Caucasian women with osteoarthritis of the knee, and 299 healthy women from the Twins UK register. They looked for differences in the signals and the ratios between the two groups.
Their analysis revealed 14 metabolite ratios that were significantly associated with osteoarthritis. The team then tested these signals to see if they were replicated in an independent sample of 76 women with knee arthritis and 100 healthy women. Two ratios - valine to histidine and xleucine to histidine - were confirmed successfully.
"The search for biomarkers, or traits, which can be used to measure or indicate the effects or progress of a condition is a hugely exciting area of clinical research," said Dr Guangju Zhai from the Department of Twin Research and Genetic Epidemiology at King's College, who led the study.
"One of the main characteristics of osteoarthritis is damage to cartilage…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."
"We hope that further research will lead to these two metabolite ratios being adopted into clinical practice, enabling doctors to diagnose the condition, or identify that osteoarthritis is developing at an earlier stage," said Professor Tim Spector, a senior author on the paper.
He added that the team's approach, known as metabolomics, could also be used to monitor the effectiveness of treatments for the condition. "At the moment we rely on X-rays and scans. Our dependence on these methods is a major obstacle to the development of new drugs for osteoarthritis."
Osteoarthritis affects an estimated 8.5 million people in the UK.
The study was funded by the European Community Framework 7 large collaborative project grant Treat-OA, Arthritis Research UK and the Wellcome Trust.
Image: Artwork illustrating osteoarthritis changes in articular cartilage. Credit: Medical Art Service, Munich/Wellcome Images
Reference
Zhai G et al. Serum branched-chain amino acid to histidine ratio: a novel metabolomic biomarker of knee osteoarthritis. Ann Rheum Dis 2010 [Epub ahead of print].
